Proceedings:

Eighteenth Annual Gulf of Mexico

Information Transfer Meeting

December 1998

U.S. Deoartment of the Interior

$JJJ Minerals V1anagement Service Gulf of Mexico OCS Region

00

OCS Study

MMS 2000-030

L:JL:JL:j POWER
Proceedings:

Eighteenth Annual Gulf of Mexico

Information Transfer Meeting

December 1998

Editors

Melanie McKay

Copy Editor

Judith Nides

Production Editor

Prepared under MMS Contract

1435-0001-30665

by

University of New Orleans

Office of Conference Services

New Orleans, Louisiana 70814

Published by

U.S. Department of the Interior Minerals Management Service Gulf of Mexico OCS Region

OCS Study

MMS 2OO003O

New Orleans

June 2000
DISCLAIMER

This report was prepared under contract between the Minerals Management Service (MMS) and the,

University of New Orleans, Office of Conference Services. This report has been technically reviewed

by the MMS and approved for publication. Approval does not signifi that contents necessarily reflect

the views and policies of the Service, nor does mention of trade names or commercial products

constitute endorsement or recommendation for use. It is, however, exempt from review and

compliance with MMS editorial standards.

REPORT AVAILABILITY

Extra copies of this report may be obtained from the Public Information Office (Mail Stop 5034) at

the following address:

U.S. Department of the Interior

Minerals Management Service

Gulf of Mexico OCS Region

Public Information Office (MS 5034)

1201 Elmwood Park Boulevard

New Orleans, Louisiana 70123-2394

Telephone Numbers: (504) 736-2519

1-800-200-GULF

CITATION

This study should be cited as:

McKay, M. and J. Nides. 2000. Proceedings: eighteenth annual Gulf of Mexico information transfer

meeting, December 1998. U.S. Dept. of the Interior, Minerals Management Service, Gulf of

Mexico OCS Region, New Orleans, La. OCS Study MMS 2000-03 0. 538 pp.

111
TABLE OF CONTENTS

Eg

LIST OF FIGURES vii

LIST OF TABLES xvii

ACKNOWLEDGMENTS xxi

iNTRODUCTION xxiii

SESSION 1A: OIL SPILL RESPONSE, RESEARCH, REGULATIONS, AND DRILLS

Co-Chairs: Mr. Joe Mullin and Mr. Michael Tolbert

SESSION 18: FISHERIES ASSOCIATIONS WITH PLATFORMS

Chair: Mr. Gregory Boland, Co-Chair: Dr. Ann Scarborough Bull 27

SESSION 1C: ATMOSPHERIC SCIENCES SESSION

Co-Chairs: Dr. Alexis Lugo-Fernández and Ms. Terry Scholten 81

SESSION 2A: SEA FLOOR MONITORING

Co-Chairs: Dr. Jack B. Irion and Dr. Richard J. Anuskiewicz 125

SESSION 2B: FISHERIES MANAGEMENT AND BIOLOGY

Chair: Mr. Gregory Boland, Co-Chair: Dr. Ann Scarborough Bull 161

SESSION 2C: NITROGEN OXIDES (NO) IMPACTS AND CONTROLS IN CENTRAL

PLANNING AREA

Co-Chairs: Ms. Terry Scholten and Mr. Jedd Sondergard 213

SESSION 1D: DEEPWATER OPERATIONS

Chair: Mr. Jim Regg, Co-Chair: Ms. Deborah Cranswick 239

SESSION 1E: STUDIES REPORTS AND RESEARCH INITIATIVES

Co-Chairs: Dr. Pasquale Roscigno and Ms. Debra Vigil 253

SESSION iF: COASTAL STUDIES AND CHARACTERIZATION

Co-Chairs: Dr. Robert Rogers and Mr. Sam Holder 267

SESSION 2E: GULFCET IIMMS/BRD OFFSHORE INVESTIGATIONS OF MARINE

MAMMALS, SEA TURTLES, AND SEABIRDS IN THE GULF OF MEXICO

Co-Chairs: Dr. Robert M. Avent and Dr. Gary Brewer 281
vi

TABLE OF CONTENTS

(continued)

Page

SESSION 2F: NORTHEASTERN GULF OF MEXICO ECOSYSTEM PROGRAM:

MISSISSIPPI-ALABAMA MARINE ECOSYSTEM MONITORING PROGRAM

Co-Chairs: Dr. Robert Rogers and Dr. Gary Brewer 311

SESSION 1G: ACOUSTIC/PRESSURE WAVE EFFECTS ON MARINE MAMMALS

AND SEA TURTLES, PART I

Co-Chairs: Dr. William Lang and Ms. Colleen Bemier 353

SESSION 1H: PHYSICAL OCEANOGRAPHY SESSION

Co-Chairs: Dr. Alexis Lugo-Fernández and Dr. Mary Boatman 403

SESSION 1J: ISSUES FOR THE MILLENN]ITJM: DEFINING SOCIAL AND

ECONOMIC IS SUES FOR THE YEAR 2000 AND BEYOND

Co-Chairs: Dr. Claudia Rogers and Dr. Harry Luton 455

SESSION 20: ACOUSTIC/PRESSURE WAVE EFFECTS ON MARINE MAMMALS

AND SEA TURTLES, PART II

Co-Chairs: Dr. William Lang and Ms. Colleen Benner 485

SESSION 2H: GIS ACTIVITIES

Co-Chairs: Dr. Norman Froomer and Ms. Michelle Morin 493

SESSION 23: PROPOSED REVISIONS TO THE MMS OIL AND GAS LEASE FORM:

A WORKSHOP FOR INDUSTRY COMMENTS

Co-Chairs: Mr. Chuck Hopson and Mr. Steve Waddell 505

INDEX TO AUTHORS 509

ATTENDEES 513
LIST OF FIGURES

Page

1B.1. Catch per unit effort (CPUE) by gear type and rig along a cross-shelf transect

in the Gulf of Mexico off Louisiana. CP: coastal pelagic fishes; OP: ocean

pelagic fishes; R: reef-associated taxa; and D/MP: demersal/pelagic fishes. 31

1B.2. Mean gut fullness ± standard error of blue runner collected at G194B during

June and July 36

1 B.3. Numerical (upper row) and volumetric contributions (lower row) of prey items

in the diet of blue runner from four sampling trips to G194B during 1996. 37

1B.4. Catch per unit effort (CPUE) ± standard error of hyperiid amphipods, decapod!

stomatopod crustaceans and copepods in surface samples directly beneath G194B

and off-rig samples located downstream from the platform. 38

1B.5. Time series of hyperiid aruphipod catch per unit effort (CPUE) beneath G194B

from 23:20 to 02:14 in surface and off-rig samples. 39

lB .6. Estimated fish density (number of fish / m3) by platform side at petroleum platforms

Grand Isle 94 (G194), South Timbalier 54 (5T54) and Green Canyon 18 (GC18). . . . 46

1B.7. Estimated fish density (number of fish! m3) by depth at petroleum platforms

Grand Isle 94 (G194) and South Timbalier. 47

1B.8. Estimated fish density (number of fish! m3) by depth at petroleum platform

Green Canyon 18 (GC18). 48

1B.9. 1B.9. Final sampling design.. 54

1 B.10. Percent coverage of pre- and post-cut fouling constituents. 64

1 B. 11. Comparison of rugosity measurements from 33.5-45.7 meters at each site 65

1B.12. Location of study site in relation to Padre Island National Seashore, Port

Mansfield, and the Rio Grand 68

18.13. Vertical stratification (total numbers at each depth) of pelagic fish species

(*preCut: with lookdowns/without lookdowns). 74

1B.14. Vertical stratification (total numbers at each depth) of reef fish species. 75

vii
LIST OF FIGURES

(continued)

Page

1C.1. Texas, 11 SeptemberOCS Contribution. 87

1C.2. 1-Hour Average Ozone, 11 September 1993Grid Cell 52,27. 90

1C.3. 8-Hour Average Ozone, 11 September 1993Grid Cell 52,27. 90

1C.4. Flow of information during development of the current-year inventory. 99

1 C.5. Frequency of occurrence of stability classes for three NOAA stations and

Breton Island during the period of May 1997 through July 1998. 106

1C.6. Stable mixed layer height nomogram for air temperature of 19°C. Lines indicate

temperature difference (Tar - Tsea) 106

1C.7. Observed turbulence intensities at Breton Island compared to relationships found

for the North Sea and North Atlantic. 107

1C.8. A demonstration of LCL (mixed) height from cloud-top temperature using

data obtained over Breton Island on 4 August 1998 at approximately 1500 GMT

(1000LT). 107

1C.9. Cloud-top temperature at approximately 16 degrees C 108

1C.10. Project schedule for Boundary Layer Study in the Western and Central

Gulf of Mexico. 123

2A.1. Drawing of the steamship New York. Courtesy Mariners' Museum,

Newport News, Virginia. 138

2A.2. Example of a crosshead steam engine, ca. 1828. 140

2A.3. Magnetic contour map of the wreck site of the New York. 142

2A.4. The sinking of the USS Hatteras by the CSS Alabama. Courtesy U.S. Navy

Photographic Center. 143

2A.5. Side-scan sonar image of the Horn Island shipwreck (22HR843). 144

2A.6. The SS Cities Service Toledo. 146
ix

LIST OF FIGURES

(continued)

2A.7. The SS Heredia. 146

2A.8. A Class IXC German U-boat, the same type as the U-166. 148

2A.9. The SS Robert E. Lee, superimposed over the side-scan sonar record of the

shipwreck. Courtesy John E. Chance & Associates, Inc 149

2B.1. The number of species in each Coefficient of Variation (CV) range. EFG is

represented by the light colored bars, WFG by the dark bars, and SB by the

medium bars. CV was calculated for all species over the six census times,

using SDT abundance. 178

2B.2. U.S. Geological Survey, BRD station sites occupied during RV Suncoaster

Cruise FCSC 97-01, Pinnacles reef tract, Mississippi-Alabama Outer Continental

Shelf. 195

2B.3. Sampling intensity for one large flat-topped pinnacle study site targeted during

BRD RV Suncoaster Cruise FCSC 97-0 1 196

2B.4. Simplistic first-order scheme of community structure among dominant fishes on

three characteristic Pinnacles biotypes. 199

2B.5. Preliminary food web model for the deep reef fish community, based on methods

proposed by Winemiller (1990), indicating primary trophic pathways identified

from samples taken during our August 1997 cruise. 204

2C. 1. 1989 Composite modeling results in micrograms per cubic meter 216

2C.2. 1990 Composite modeling results in micrograms per cubic meter 216

2C.3. 1991 Composite modeling results in micrograms per cubic meter 217

2C.4. DeNOx Silencer specifications. 233

1 D. 1. Gulf of Mexico deepwater exploratory wells in more than 1000 feet of water. 242

1 B. 1 Northern Gulf of Mexico showing study site locations for submersible operations

(triangles) and mega-site areas for geophysical survey (shaded rectangles). Depth

contours are in meters. 263
x LIST OF FIGURES

(continued)

Nc Page

iF. 1. Areas of 1996 Wetland Habitat Mapping Update 274

2E. 1. Location of hydro graphic stations made by ft/V Gyre and IfV Oregon-Il during

four GulfCet II cruises that surveyed the NE Gulf of Mexico in early and late

summer 1996 and early and mid summer 1997. 293

2E.2. Dynamic topography (cm, 0 m to 800 m) of the deepwater focal area, as determined

from 152 hydrographic stations made on R/V Gyre cruise 96G-06. 294

2E.3. Dynamic topography (cm, 0 m to 800 m) of the deepwater focal area, as determined

from 107 hydrographic stations made on ft/V Gyre cruise 97G-08. 295

2E.4. Property-property plot of bottle data from RAT Gyre cruise 96G-06, illustrating how

depth of the 190 C isotherm can be used as a proxy for 10 uM nitrate concentration. . 296

2F.1. Locations of final monitoring sites. 314

2F.2. Location map showing the study areas on the Mississippi-Alabama outer continental

shelf. Boxes show prior studies in the area. Small, dark boxes show the five megasites

surveyed with a side-scan sonar and subbottom profiler for this project. Hachured

areas show deltas described in Kindinger (1988) and Sager etal. (submitted). 319

2F.3. TAI[U2 side-scan sonar mosaic of Megasite 1. Vertical (north-south) image strips

175 m in width have been combined to make a sonar mosaic several kilometers on

a side. Dark areas (sonar-bright) show places on the seafloor where sound is strongly

reflected back to the sonar whereas light areas (sonar-dim) show places where sound

is not strongly reflected or there is an acoustic shadow. In general, rough seafloor and

coarse textured sediments yield sonar-bright returns (Johnson and Helferty 1990).

The boxes labeled Site 1 to Site 3 show the locations of monitoring sites within the

megasite. Coordinates are UTM x and y (in meters). 320

2F.4. TAMU2 sonar bathymetry map of Megasite 1. Contours at 1-m intervals with every

multiple of 5-rn shown with a heavy line. Coordinates are UTM x and y (in meters). . 322

2F.5. Seafloor characterization from ROV photo stations for monitoring Site 1. Symbols

show station locations; gray lines are 1 -m bathymetric contours for reference. Each

panel describes a different characteristic from Table 2F. 1. The sides of each box are

300 mm length. 325
LIST OF FIGURES

(continued)

Page

2F.6. Ternary diagrams showing the composition of Cruise 1 C grab samples. At top, all

samples are plotted on a sand-clay-silt diagram with values normalized after removal

of the gravel fraction. At bottom, silt and clay are grouped (mud) and the gravel-size

fraction is considered. 326

2F.7. Mass fluxes recorded in sediment traps during the four sampling periods of the

first year of sampling (May 1997 to May 1998). Note the logarithmic flux scale. . . . 328

2F.8. Map showing the locations of the four sites at which instrument moorings are

located. Site 1 is in Megasite 1; Site 4 is in Megasite 2; Site 5 is in Megasite 3;

and Site 9 is in Megasite 5. 332

2F.9. Summary of current meter observations at Site 1A at 16 meters above the bottom

(mab) for the period 23 May 1997 through 24 April 1998: Basic statistics (top),

scatter plot (middle), and percent joint occurrence of speed and direction (bottom). . 334

2F. 10. Temperature-salinity relationships for the five cruises in the first year of the

program. A composite T-S plot is given for each cruise (3a-e), and for all casts

of all cruises (3f). 335

2F. 11. September 1998 stick vector plot of currents recorded at 16 meters above the

bottom (mab) at Sites 1, 4, 5, and 9. North is vertically upward, and a scale for

the magnitude is in the left side of each panel. 337

2F.12. September 1998 current speeds recorded at 4 meters above the bottom (mab) at

Sites 1, 4, 5, and 9 338

2F.13. Turbidity (NTU) recorded at Sites 5A and SB at 2.3 meters above the bottom

during 20 July through 14 October 1998. 339

2F.14. Locations of final monitoring sites within the Mississippi/Alabama pinnacle trend

in water depths of 60 to 100 m. 342

1G.1. Turtleshot#1. 359

10.2. An example of a Langrangian computational mesh. 360

1G.3. An example of a Eulerian computational grid. 361

xi
xii

LIST OF FIGURES

(continued)

Page

1 G.4. The seismic industry will continue to increase the amount of in-sea equipment

for the acquisition of 3D seismic surveys with spreads of up to 1,200 meters or

greater and streamer lengths of up to 12 km 364

1G.5. The industry can conthe equipment to accomplish two objectives at once. 365

1G.6. The marine vibrator 366

1G.7. The vibrator output signal is very stable and repeatable.. 366

1G.8. The idea of water pushing out oil, or water flowing in behind oil is shown here.

Oil is medium gray, water is black. 367

1 G.9. The basic concept of 3D seismic time-lapse monitoring is illustrated here through

the use of synthetic data. 367

1G. 10. A North Sea field example of seismic aftributes used to map the fluid distribution

in a reservoir under production. 368

1G. 11. A depiction of an array of vertical cables and the trenching of a cable into the

seafloor. 370

1G.12. A data comparison indicating the improved resolution and greater continuity in

events delivered by the seabed cable systems. 371

1G.13. An example of imaging beneath gas using S-wave energy 372

1G.14. P-wave and S-wave velocity imaging beneath salt bodies. 373

1G. 15. An illustration of how a 4-component seismic operation might be laid out 374

10.16. A summary representation of the present cost of seabed cable surveys. 375

1G.17. Examples of impulse and tonal sounds 385

1G.18. Sample results of hearing sensitivity testing on marine mammals. 388
LIST OF FIGIJRES

(continued)

Page

1G.19. Diagram of the TTS testing enclosure. At listening station 1, the dolphin got an

Si signal from projector A, then proceeded to listening station 2 for hearing

threshold testing. Projector B delivered the S2 tones, and projector C emitted the

white noise that served as level background. Monitoring hydrophone D was used

to record louder Si signals for precise determination of acoustic amplitude at the

dolphin's lower jaw. Monitoring hydrohpone E recorded the dolphin whistles

emitted by the animal when it heard an S2 tone. 389

1 G.20. A schematic illustration of the sequence of experimental procedures. 391

1 G.2 1. A predictive model of damage created from the energetic correlates of damage

merged with measured dimension, mass and resilience of auditory structures. 392

1 H. 1. Location of MMS Northeast Gulf of Mexico meteorological data sites 407

1H.2. MMSMet mean annual winds 1995-1996 410

1H.3. Representative examples of eight synoptic weather types for New Orleans,

Louisiana (from Muller and Wax 1977). 411

IH.4. Monthly mean Sea Surface Temperature images (Left: March 1996; Right: August

1996). SST is shaded according to the color bar insert. Contours represent altimeterderived sea surface topography rendered for the 1 5th day of each corresponding month.

Contour labels are shown in [cm]. White contours represent high elevations and black

contours represent depressions. Vectors represent monthly-mean velocities derived

from drifter positions within 25x25 km boxes in the NEGOM. Vectors are colored

black if they have a northward component and white if they have a southward

component 416

1H.5. Station numbers for CTD!bottle stations on cruise N2 conducted during 5-16

May 1998; locations of four SAIC moorings on 100-rn isobath along northwestern

wall of DeSoto Canyon; and locations of two nearshore meteorological stations.....420

1H.6. Sea surface height anomaly from satellite altimeter data showing study area

averaged for 21 April-4 May 1998 (courtesy of Robert Leben, University

of Colorado). 421

xl"

1H.7. Gridded shipboard ADCP vectors at 50 m plotted on contours of geopotential

anomaly of 3-rn surface relative to 800 m. 422
xiv

LIST OF FIGURES

(continued)

Page

1H.8. Potential temperature (°C) near the bottom on cruise N2, 5-16 May 1998. 423

1H.9. (Upper) potential temperature (°C) and (lower) salinity on line 5 of cruise N2,

5-16 May 1998. 424

1H.l0. Salinity at 3.5 m derived from CTD data collected on cruise N2, 5-16 May 1998. . . 425

111.11. Density anomaly in kgm3) on lines 3 and 9 on cruise N2, 5-16 May 1998. 426

1H.12. Dissolved oxygen (mLL') near the bottom on cruise N2, 5-16 May 1998. 427

1H.13. Nitrate (.imoFL') at 3.5 m (upper) and near the bottom (lower) on cruise N2,

5-l6May 1998. 429

1H.14. Map of mooring positions (solid dots), standard grid hydrographic (CTD) stations

(open squares), and meteorological buoys and CMAN stations (solid diamonds). .. . 432

1H.15. Geostrophic velocities relative to 1,000 dbar calculated from CTD data for the

March (PE-9830) and August (PE-9908) hydrographic cruises. 433

1H.16. 40-hour low-passed filtered temperature time series from the near-bottom

instruments at the shelf-break moorings (Al through El). Top plot is from

the 180 m level of the D9 mooring in the canyon. Plots without ordinate axes

have the same temperature scale as the Al time series 435

1H.17. Correlation coefficient between velocities derived from position fixes of surface

drifters tracked during February 1996 and April 1997 and model velocities at

5 m as a function of horizontal coordinates for Northeastern Gulf of Mexico.

The upper panel is for the east-west velocity component and the lower panel

is for the south-north velocity. 438

lH. 18. Time series of correlation coefficient as in Fig. 1 but area-averaged daily during

February 1996 - April 1997 for the east-west velocity component (upper panel)

and south-north velocity component (middle panel). The time series of south-north

wind stress component at Pensacola is shown in the lower panel. 439
LIST OF FIGURES

(continued)

111.19. Vector plots, in the DeSoto Canyon area, for 20 March 1996 (left column) and

6 October 1996 (right column) of wind stress (upper panel), model velocity at

5 m (middle panel), and velocity derived from satellite-tracked surface drifters

(lower panel). 440

xv
LIST OF TABLES

& Page

18.1. Randomized block design ANOVA (block on platform side) of log fish density

data (log (number fish * m3 )) from South Timbalier 54 with platform side, depth

and the interaction of depth and side. 44

18.2. Randomized block design ANOVA (block on platform side) of log fish density

data (log (number fish * m3 )) from Grand Isle 94 with platform side, depth and

the interaction of depth and side. 44

1B.3. Randomized block design ANOVA (block on platform side) of log fish density

data (log (number fish * m3 )) from Green Canyon 18 with platform side, depth

and the interaction of depth and side. 45

1B.4. Estimated fish mortality. 56

18.5. Red snapper tag-recovery study. 57

1B.6. Red snapper population and mortality estimates. 57

1B.7. Fouling species identified from photographic transects on NPI 72 A, NPI 59 A,

EB 165 A, and HI 389A 62

1B.8. Vertical zones delineated during analysis of NPI 72 A, NPI 59 A, EB 165 A,

andHI389A. 63

18.9. Numbers of fish observed during surveys for the pre and post-cut of NPI A72A,

and NPI A59A (control). 70

1B.10. Numbers of fish at each depth found o the pre- and post-cut survey of North

Padre Island A72A and North Padre Island A59A (control). 73

1 C. 1. Maximum Predicted OCS Contributions to the Daily Maximum 1-Hour Average

Ozone Concentration, 1993 Emissions. 84

1C.2. Maximum Predicted OCS Contributions to the Daily Maximum 8-Hour Average

Ozone Concentration, 1993 Emissions. 86

1C.3. Comparison of 8-Hour and 1-Hour OCS Contributions to Daily Maximum Ozone

Concentrations. 89
LIST OF TABLES

(continued)

1 C.4. OCS emission inventory source categories 98

1C.5. BAMP preferred option. 113

1C.6. Breton NTL alternative. 115

2B.1. Survey effort. Number of stationary (SDT) and roving (RDT) visual fish surveys

conducted during each cruise to the EFG, WFG and SB. 170

2B.2. Cumulative species list. Compiled from three years of semi-annual surveys at

the Flower Garden Banks National Marine Sanctuary. Species seen during Roving

(RDT) and Stationary (SDT), as well as those sighted during other dives are listed.

Surveys were conducted in depths of 22-32 m. Species seen at the surface (sfc) and

those seen at night (ngt) are indicated. New documented records for the FGB or SB

are indicated with an asterisk (*) in the right-most column. 171

211.3. Similarity analyses. Values in the top of the matrix are Jaccard coefficient values

(3), comparing the species present at the EFG, WFG and SB, based on RDT data.

Values in the bottom of the matrix are proportional similarity values (Cij), comparing

the species abundance of the EFG, WFG and SB. The Cij values were calculated

using SDT abundance data for the top 53 species excluding the schooling planktivores.

The similarity values are based on all surveys conducted during the study. 177

2B.4. Elasmobranchs reported at mid-shelf (MSB) and the Flower Garden Banks (FGB)

in the scientific literature. Stetson Bank is classified as a mid-shelf bank, whereas

FGB are classified as outer-shelf banks. National Marine Fisheries Service considers

species denoted with an asterisk (*) as being overfished, in their annual report to

Congress (1998). 185

2B.5. Seasonal occurrence ofjuvenile (J) and adult (A) elasmobranch species reported in

this study are shown in the upper section of the table. The presence of both juveniles

and adults are denoted by JA. Seasonal distributions of elasmobranchs at Stetson (ST)

and the Flower Garden Banks (FOB) are portrayed in the lower section of the table.

Black blocks represent confirmed reports of the species, while grey blocks represent

unconfirmed reports. 188
LIST 01? TABLES

(continued)

Page

2B.6. Relative abundance (%) of fishes at reefs of varying topographic profile from

BRD Cruise FCSC 97-01, August 1997. Data derive from ROV videotape analyses.

Parameter total number of individuals per species divided by total number of

fishes of all species x 100 for a single target reef site representing each category.....198

2B.7. Prey items identified in stomach contents of specimens collected from the

Mississippi-Alabama outer continental shelf. The number of specimens examined

that contained prey is indicated. "X" indicates presence of prey groups in stomach

contents, while "L" indicates presence of planktonic larval forms for each prey

group, such as gastropod veligers and shrimp zoeae. 205

2B.8. Feeding guilds of deep reef fishes along the Mississippi-Alabama outer continental

shelf. Determination of feeding guild is based on stomach contents identified in this

study, or from food habits given by Randall (1967). 206

2C. 1. Some options for handling the issue. 218

2C.2. Reduction options, effectiveness and costs 222

2C.3. Reduction options, advantages disadvantages. 228

2C.4. Summary cost, Mobile 916 NOx control. 232

1 E. 1. Summary of principal community-level sampling sites and pertinent characteristics.

(For locations, see Figure 1E. 1.) 264

1E.2. Program team and roles 265

1. Group-size, density and abundance estimates of cetacean species from aerial surveys

in the continental shelf and slope study areas in the northeastern Gulf of Mexico

during summer and winter 1996-98 (n - number of groups, S - mean group size, D -

animals/100 km2, N - abundance estimate, CV - coefficient of variation, LCI and

UCI - lower and upper limits of log-normal 95% confidence interval). 301

1. Geologic descriptors of the seafloor at ROV photo stations 323

xix

2F.2. Mean coverage by taxa for all treatments after 6 months. 350

2F.3 Standing stock coverage by treatments after 6 months. 350
xx

LIST OF TABLES

(continued)

2F.4. Coverage changes due to ecological processes 350

1G. 1. The relationship between the material properties in front of and behind the shock. 358

1G.2. Scientific panel members at the MMS Pacific OCS Region High-Energy Seismic

Workshop, Pepperdine University, Malibu, California, 12-13 June 1997. 396

1 H. 1. Data inventory in MMS database. 406

1 H.2. Evaluation of the skill of the model to reproduce observed events. 442

1 H.3. Fishes and invertebrate groups reported by various observers to be either dead (D)

or obviously distressed (S). No systematic collections were made, and the list is

conservative. Common names are used when identification of the species was

not verified. 445

1J.1. Study areas and related counties/parishes and communities 459

1J.2. Predicted and Actual Employment Levels, Bull Arm Construction Site, 1990-1995. . 478

2G.1. How oil and gas exploration activities may impact sea turtles. 491
ACKNOWLEDGMENTS

The Minerals Management Service thanks all ITM participants. Recognition goes to the speakers

whose timely individual and panel presentations stimulated discussions and exchange of information.

Authors are listed by name with their articles and again in an index at the back of this publication.

We are grateful to the chairs and co-chairs for the many hours spent in organizing and chairing the

sessions and for spending time gathering presentation summaries. They are listed by name in the

table of contents as well as at the beginning of each session.

Special recognition is given to staff who contributed immensely to the overall success of the

meeting: Rose Hampton and Vita Jones, administrative support; Donna Bourg, Internet and

administrative support; Joe Perryman, computer technical support.

The University of New Orleans, Office of Conference Services, was the contractor responsible for

the meeting. The dedicated staff and subcontractors play an integral role in the execution of this

meeting and the completion of the proceedings. Their tireless efforts are greatly appreciated.

The staff of the Airport Hilton were personable and accommodating to our countless requests.

xxi
INTRODUCTION

Ms. Debra L. Vigil

Environmental Sciences Section

Minerals Management Service

Gulf of Mexico OCS Region

The primary purposes of the ITM are (1) to provide a forum for interchange on topics of current

interest relative to environmental assessments in support of offshore oil and gas activities in the Gulf

of Mexico OCS Region; (2) to present the accomplishments of the MMS Environmental Studies

Program for the Gulf of Mexico and of other research programs or study projects; and (3) to foster

an exchange of information of regional interest among scientists, staff members, and decisionmakers from MMS, other Federal or State governmental agencies, regionally important industries,

and academia and to encourage opportunities for these attendees to meet and nurture professional

acquaintances and peer contacts.

The ITM agenda is planned and coordinated by the MMS staff of the Gulf of Mexico OCS Regional

Office around the three themes mentioned aboveissues of current interest to the Regionor MMS

oil and gas program; accomplishments of the agency; and regional information exchange.

Presentations are by invitation through personal contacts between session chairpersons and speakers

who have demonstrated knowledge or expertise on the subject.

The ITM is considered a meeting of regional importance and is one of the Region's primary outreach

efforts. Attendance in recent years has been 300-400 people, including scientists, managers, and

laypersons from government, academia, industry, environmental groups, and the general public.

Support funding is provided through the MMS Environmental Studies Program. Logistical support

for the ITM is provided by a contractor and subcontractors selected through the Federal procurement

process. A proceedings volume is prepared for each ITM based on summaries of brief technical

papers submitted by each speaker and on each session chair's added comments.
Regional Oil Spill Response Plans and

30 CFR Part 254

Unannounced Oil Spill Drill Program

The Minerals Management Service Cutting

Edge Oil Spill Response Research

Availability and Capabilities of 'Ohmsett":

the National Oil Spill Response Test Facility

SESSION IA

OIL SPILL RESPONSE, RESEARCH, REGULATIONS, AND DRILLS

Co-Chairs: Mr. Joe Mullin and Mr. Michael Tolbert

Date: December 8, 1998

Presentation Author/Affiliation

Mr. David M. Moore

Minerals Management Service

Gulf of Mexico OCS Region

Ms. Angie D. Gobert

Minerals Management Service

Gulf of Mexico OCS Region

Mr. Joseph V. Mullin

Minerals Management Service

Engineering and Research Branch

Mr. Michael E. Whitehead

Mr. William T. Schmidt

MAR, Incorporated

Diamondhead, Mississippi

1
REGIONAL OIL SPILL RESPONSE PLANS AND 30 CFR PART 254

Mr. David M. Moore

Minerals Management Service

Gulf of Mexico OCS Region

One facet of the Oil Pollution Act of 1990 (OPA), passed in August of that year, was the amendment

of section 31 1(j) of the Federal Water Pollution Control Act (FWPCA) which strengthened

provisions concerning oil-spill prevention efforts and spill response capability. Under Executive

Order 12777, the Minerals Management Service (MMS) is responsible under FWPCA for issuing

regulations requiring owners or operators of offshore facilities to prepare and submit oil spill plans.

The FWPCA requires that owners or operators of offshore facilities, including associated pipelines,

prepare and submit response plans. They must also ensure the availability of private personnel and

equipment to contain discharges of oil and hazardous substances. The new authorities apply to all

offshore areas including state submerged lands but not to deep-water ports subject to the Deep Water

Port Act.

On 12 August 1992, MMS published an advance notice of proposed rulemaking (ANPR) in the

Federal Register. That notice informed the public that MMS was developing regulations governing

1) the establishment of procedures, methods, and equipment to prevent and contain discharges of oil

and hazardous substances; 2) the preparation and submission of response plans; and 3) the periodic

inspection of containment booms and response equipment. The notice solicited information

concerning the development of these requirements.

MMS reviewed and analyzed the comments received from the ANPR and published a notice of

proposed rulemaking covering these requirements on 13 January 1995. To allow owners and

operators of facilities to continue to operate beyond 18 February 1993, the established date for

submittal of spill response plans, MMS developed an interim final rule. The interim final rule

ensured that spill response pians were in place at the earliest possible date and that the beneficial

environmental effects of spill response plans were realized while more extensive regulations to

implement OPA were being developed. The interim final rule, which was set to expire on 18

February 1995, was subsequently extended to the effective date of the final rule.

On 25 March 1997, MMS published its final rule governing Oil Spill Response Plans (OSRPs) and

related requirements for facilities located seaward of the coastline, including those facilities located

in both state and federal offshore waters (30 CFR Part 254). These regulations became effective on

23 June 1997. Interim guidance on the preparation of regional oil spill response plans based upon

the new regulations was provided through a Notice to Lessees and Operators (NTL) No. 97-15, dated

27 June 1997.

MMS has prepared the final guidance regarding the preparation of regional oil spillresponse plans,

with publication tentatively scheduled for January 1999. The subject NTL was prepared by engineers

and biologist from Field Operations and Leasing and Environment directly responsible for Oil Spill

3
4

Contingency Plan (OSCP) review and approval. During the development process, the draft NIL was

forwarded for review and comment to staff at agencies in Alabama, Mississippi, Louisiana, and

Texas responsible for spill response and management. Further, the draft NTL was forwarded to and

reviewed by members of the American Petroleum Institute, the Offshore Operators Committee, the

National Ocean Industries Association, and the Independent Petroleum Association of America.

Recommendations for NTL revisions were presented both in written form and during an informal

presentation by OOC representatives to MMS. Suggestions that clearly represented an improvement

in the NTL were incorporated as appropriate.

One of the many features of the regional oil spill response plans that will be a product of the new

NTL will be documents of similar formats that contain discreet plan components. Such an approach

was chosen to help simplify plan development and long-term plan maintenance without

compromising plan integrity and effectiveness in ensuring a prompt, efficient response to an oil spill.

Additionally, this approach, in conjunction with MMS initiatives to standardize plan reviews, will

reduce the amount of time required by MMS staff to review response plans for regulatory

consistency and will thus result in quicker plan approvals. For owners and operators, the new

approach should equate to a much clearer understanding of plan requirements and the elimination

of numerous revisions brought about by MMS review to bring plans into compliance with the

regulations. For both owners and operators and MMS alike, the new approach should mean

improved staff productivity and reduced costs.

The Table of Contents for a typical OSRP to be prepared following publication of the forthcoming

NTL is given below. As the NTL is undergoing final review in the NTL approval process, sections

are subject to change.

Section 1. OSRP Quick Guide (Optional)

Section 2. Preface

Table of Contents

Record of Revisions

Cross Reference Table

Section 3. Introduction

Companies Covered

Purpose arid Use

Types of Leases and ROW Pipelines

Facility Information Statement

Contract Certification Statement

Section 4. Organization

Qualified Individual

Spill Management Team

Spill Response Operating Team

Oil Spill Removal Organizations
Section 5. Spill Response Operations Center and Communications

Spill Response Operations Center

Communications

Section 6. Spill Detection and Source Identification and Control

Spill Detection

Pipeline Spill Detection and Location

Source Control

Section 7. QI, SMT, SROT, and OSRO Notifications

Reporting Procedures

Company Contact Information

SROT Contact Information

OSRO Contact Information

Internal Spill Reporting Forms

Section 8. External Notifications

Reporting Procedures

External Contact Information

External Spill Reporting Forms

Section 9. Available Technical Expertise

Section 10. Spill Assessment

Locating a Spill

Determining the Size and Volume of a Spill

Predicting Spill Movement

Monitoring and Tracking the Spill Movement

Section 11. Resource Identification

Section 12. Strategic Response Planning

Section 13. Resource Protection Methods

Section 14. Mobilization and Deployment Methods

Section 15. Oil and Debris Removal Procedures

Offshore Procedures

Shallow Water Procedures

Section 16. Oil and Debris Disposal Procedures

Section 17. Wildlife Rehabilitation Procedures

5
6

Section 18. Dispersant Use Plan

Dispersant Inventory

Toxicity Data

Application Equipment

Application Methods

Conditions for Use

Approval Procedures and Forms

Section 19. In Situ Burning Plan

In Situ Burning Equipment

Procedures

Environmental Effects

Safety Provisions

Conditions for Use

Decision Processes

Approval Procedures and Forms

Section 20. Alternative Chemical and Biological Response Strategies (Optional)

Product Inventory

Toxicity Data

Application Equipment

Application Methods

Conditions for Use

Approval Procedures and Forms

Section 21. Documentation

Appendix A. Facility Information

Table 1

Table 2

Table 3

Table 4

Appendix B. Training Information

OSRC/IC, SMT, and QI

Other SMT Members

SROT

Location of Records

Appendix C. Drill Information

Appendix D. Contractual Agreements
Appendix E. Response Equipment

Equipment Inventory

Inspection and Maintenance Programs

Appendix F. Support Services and Supplies

Appendix G. Notification and Reporting Forms

Internal Spill Reporting Forms

External Spill Reporting Forms

Appendix H. Worst Case Discharge Scenarios

Facility Information

Volume

Land Segment Identification

Resource Identification

Response

Appendix I. Bibliography

Items of significance noted in the NTL associated with MMS efforts to improve the plan while

reducing requirements are the provision for a company-defined "OSRP Quick Guide," which is

intended to serve as an abbreviated set of instructions for owners and operators on key actions,

contacts, and requirements during the early phases of a spill response; the reduction of copies of

initial response plans and subsequent modifications required by MMS from two copies, toone copy;

the reduction of the plan update frequency from once a year, to every two years; the elimination of

response time sheets and trajectory land impact probabilities, sensitive resource identification and

protection strategies; and the option to certifi that contracts are in effect with oil spill removal

organization(s) instead of providing a fully executed contract.

With the effective date of the NTL to be sixty days following its publication, owners and operators

will have a number of options on when they must submit a new OSRP. Owners and operators who

have not filed a regional OSRP under existing interim requirements must submit a plan in

compliance with the new NIL. Those owners and operators with approved oil spill contingency

plans may either 1) amend the plan in compliance with the new NTL at the time of the next annual

update, or 2) amend the plan using existing interim requirements at the time of the next annual

update but then amend the plan in compliance with the new NTL at the time of the following annual

update. Response plans submitted in various phases of revision or those that have never been

approved will be reviewed on a case by case basis, with the status of the owner's or operator's worst

case certification being a key factor in determining if the response plan must be submitted under

guidance provided in the new NIL.

Following publication of the NTL, it will be forwarded by direct mail to those on the S

NTL mailing list. Additionally, copies may be obtained from the MMS Web Site at

7
8

http://www. gomr. mms. gov/topicl/html, or by contacting the MMS GOMR Public Information office

at 504-736-2519 or 1-800-200-GULF.

David Moore works with MMS in the Gulf of Mexico region as a Petroleum Engineer in the Pipeline

Section. His current responsibilities include review of pipeline applications and pipeline repair

procedures. Additionally, he reviews oil spill response plans and conducts unannounced spill drills

for companies with facilities limited to right-of-way pipelines.

UNANNOUNCED OIL SPILL DRILL PROGRAM

Ms. Angie D. Gobert

Minerals Management Service

Gulf of Mexico OCS Region

This paper discusses the history and evolution of the Minerals Management Service (MMS) Gulf

of Mexico Outer Continental Shelf Region's (GOMR) Unannounced Oil Spill Drill Program. This

paper also contains a few statistics regarding the GOMR Unannounced Oil Spill Drill Program.

The MMS is a regulatory agency within the United States Department of the Interior (DOI) charged

with responsibility for administering the Outer Continental Shelf (OCS) oil, gas, sulphur, and

minerals program. Its responsibilities include the regulation of operations to ensure safety,

conservation of natural resources, and protection of the environment.

Of particular concern to the MMS and the general public is the prevention of and response to oil

spills. The MMS has extensive regulations designed to minimize spill occurrences and to ensure that

operators respond effectively to spills when they happen. To ensure an effective response, the MMS

requires oil spill response plans, training of those persons responsible for the response, and periodic

drills and other exercises. The MMS can also conduct unannounced oil spill drills as part of its

regulatory approach.

The Unannounced Oil Spill Drill Program was launched by the GOMR in May 1989 via a Letter to

Lessees and Operators (LTL). This program was instituted to test oil spill response preparedness of

operators in the Gulf of Mexico. On 26 June 1989, the GOMR issued a second LTL to all oil and gas

operators in the Gulf of Mexico. This LTL implemented the program and explained the procedures

concerning the various types of oil spill containment and cleanup drills the GOMR would be

conducting. In 1992, the MMS published Notice to Lessees and Operators (NTL) No. 92-04. One

of the results was that holders of OCS right-of-way (ROW) pipelines in the Gulf of Mexico would

be subject to unannounced drills.
9

On 3 February 1994, a Memorandum of Understanding (MOU) among the Department of

Transportation, the DOT, and the Environmental Protection Agency became effective. This MOU

established Federal jurisdictional boundaries for offshore facilities including pipelines. Under this

MOU, the MMS is responsible for offshore facilities located seaward of the coastline, including

those in state offshore waters.

The MMS has entered into MOU' s with both the Louisiana Oil Spill Coordinator's Office (LOSCO)

and the Texas General Land Office (TGLO). The MOU' s are for the purpose of coordinating and

implementing consistent requirements for oil spill prevention and response. Among the provisions

of these MOU's is the conducting ofjoint drills with LOSCO and TGLO. These MOU's became

effective in late 1994.

On 23 June 1997, the MMS published its final rule implementing the provisions of the Oil Pollution

Act of 1990 (OPA 90). These regulations contain a provision in paragraph (g) of 30 CFR 254.42,

Exercises for Your Response Personnel and Equipment, for the MMS to conduct unannounced oil

spill drills. The GOMR Unannounced Spill Drill Program continues under this new authority.

As a result of OPA 90, the U. S. Coast Guard developed the National Preparedness for Response

Exercise Program (PREP) to meet the intent of Section 4202(a) of OPA 90 as a workable exercise

program. It was developed to provide a mechanism for compliance with the exercise requirements

while being economically feasible for the government and oil industry to adopt and sustain.

The PREP is a unified Federal effort and satisfies the exercise requirements of Department of

Transportation agencies (the U.S. Coast Guard and the Office of Pipeline Safety), the Environmental

Protection Agency, and the DOT's MMS. These exercises, which we call drills, also may include the

participation of State and local government agencies. Completion of the PREP exercises will satisfy

all OPA 90 mandated oil spill response exercise requirements. Guidelines for the various types of

PREP drills have in place since 1 January 1994.

The 1989 LTL outlined four types of unannounced drills and exercises. They are:

Unannounced Drill with Equipment Mobilization Only

Unannounced Drill with Equipment Mobilization and Deployment

Spot "Table-Top" Drill

Announced "Table-Top" Simulation of a Large Oil Spill (to date no drill of this type has

been held)

The remainder of this paper describes how an unannounced oil spill drill is planned, conducted, and

evaluated.

When the GOMR schedules an unannounced oil spill drill, the first step is to select an operator or

pipeline ROW holder to drill. The selection is made by the Regional Supervisor for Field Operations,

the Plans Section Chief, or the Oil Spill Program Administrator. The selection is made using criteria

that includes: new operators, operators with new oil spill response organizations, operators who have
10

exhibited past poor performance, operators with facilities storing or transporting large volumes of

oil, and operators with facilities near highly sensitive areas.

The GOMR Oil Spill Program Administrator usually takes the lead in conducting the drill. The lead

position is titled "Monitoring Team Leader." The Monitoring Team Leader develops a plausible

scenario for the drill. He utilizes information gathered from various sources such as computer data

and MMS files and records. After an oil spill trajectory analysis is performed, the Monitoring Team

Leader arranges the logistics for the drill. This includes selecting a Monitoring Team from personnel

in the GOMR Office of Field Operations, the GOMR Office of Leasing and Environment, and

appropriate Federal or State agencies. This also includes arranging for the delivery of the scenario

to the offshore facility (if possible) and briefing the Monitoring Team on the scenario and the

expectations for the drill.

On the day of the drill, the Monitoring Team arrives at the operator's Command Center to monitor

the response efforts of the Oil Spill Response Coordinator and the Spill Management Team. Upon

arrival, the Monitoring Team Leader asks to speak with the Response Coordinator. The Monitoring

Team Leader informs the Response Coordinator that the Monitoring Team is there to conduct an

unannounced oil spill drill. After notification from the field, which is planned to happen

simultaneously with the arrival of the Monitoring Team at the Command Center, the scenario is

reviewed and the Ground Rules are established. The scenario sets up the situation for the drill, and

the Ground Rules tell the operator what the GOMR expects of him.

During the course of the drill, the operator is expected to respond as if the scenario were real. The

Ground Rules contain instructions on what can and cannot be simulated. The unannounced oil spill

drills usually take place in realtime, even for simulated actions. In other words, even if an action is

simulated, the operator must behave as though the action were actually taking place and allow the

necessary time to complete the action.

While the operator responds to the scenario, the Monitoring Team observes the actions of the

Response Coordinator and his Spill Management Team. During these observations, the Monitoring

Team may use prepared evaluation forms or just make notes. The Monitoring Team Leader usually

concludes the drill after the operator has explored all of his response options, determined an

appropriate and adequate response, initiated simulated response efforts, and calculated the times for

response equipment and personnel to arrive at the site of the simulated spill.

The initial evaluation of the unannounced oil spill drill occurs at the onsite debriefing. At the

conclusion of the drill, the Monitoring Team Leader asks the Response Coordinator to discuss his

response actions. The discussion may include acknowledgments of what was done well and

recommendations for improvement of what was not done so well. This discussion is open to the

GOMR Monitoring Team as well as the other Spill Management Team members.

The second phase of the evaluation is the operator's written report. This report should include, but

not be limited to, a chronology of all events, copies of each participant's log, a summary of the status

of all response efforts at the time the drill is concluded, and any comments that will assist the GOMR
11

in improving future unannounced oil spill drills. The operator must submit this report to the GOMR

within 15 days of the date of the drill.

The GOMR will respond to the operator with a critique which includes the comments, observations,

and recommendations of the Monitoring Team. It is the goal of the GOMR to transmit this critique

to the operator approximately 30 days after it receives operator's evaluation.

The GOMR evaluates each unannounced oil spill drill based on the three major categories of the

Response Plan Core Components outlined in the PREP guidelines. Only those Response Plan Core

Components that are demonstrated during the unannounced oil spill drill will be considered for

MMS drill component credit. The three major categories of PREP Response Plan Core Components

are Organizational Design, Operational Response, and Response Support.

Organizational Design consists of three components:

Notifications

Staff Mobilization

Ability to Operate Within the Response Management System Described in the Response

Plan.

The MMS expects operators to make all the necessary notifications, such as the National Response

Center, the local U. S. Coast Guard Marine Safety Office, and other appropriate federal and state

agencies. Staff mobilization encompasses the assembly of the Spill Management Team and other

necessary field personnel to carry out response efforts. The ability to operate within the response

management system described in the response plan pertains to the effectiveness of the organizational

structure to accomplish an adequate response.

Operational Response consists of six components:

Discharge Control

Assessment

Containment

Recovery

Protection

Disposal

Operational Response relates to spill source abatement, spill assessment, identified cleanup strategies

for the spill, protection of sensitive resources and involved personnel, and accommodations for

disposal.

Response Support consists of five applicable components pertaining to the ability to

establish an effective communication system

provide effective transportation to facilitate the cleanup and support activities,
12

provide all personnel associated with the response necessary support, such as administrative

management, overnight accommodations, and suitable feeding arrangements for a sustained

response,

procure sufficient personnel, equipment, and support equipment to mount and sustain an

organized response, and

document decisions and actions.

The GOMR recently instituted the Pass/Fail rating system. The system is designed to categorize an

operator's performance in each of the three ma] or PREP Response Plan Core Components categories

(Organizational Design, Operational Support, Response Support). The rating received will then

determine, based upon policy, the subsequent actions taken by the GOMR.

When an operator receives a Pass rating for any of the three categories, the GOMR evaluation letter

contains commendations and recommendations for improvement. Following are examples of commendations: "The assembly of the Spill Management Team was quick," and "The Command Center

was equipped with essential charts, maps, and other visual aids," and "Disposal was addressed early

in planning the response." Examples of recommendations: "Your Spill Management Team should

consider further training in the area of Dispersant Use"; "You should better utilize the services of

oil spill experts"; "Consider all available forms of transportation in your response efforts."

When an operator receives a Conditional Pass rating for any of the three categories, the GOMR

evaluation letter contains directives that are to be carried out by the operator within a specified time

frame. These directives could include specific changes in his oil spill response plan, remedial

training for response personnel in specific areas, or conferences with the Oil Spill Program

Administrator and other appropriate officials. After these directives are accomplished, the GOMR

may re-drill the operator to determine if the condition(s) can be removed.

An operator will receive a Fail rating if he or she is unsuccessful in carrying out an adequate

response within an appropriate time in accordance with his oil spill response plan. The evaluation

letter will contain directives that are to be carried out by the operator within a specified time frame.

As with the Conditional Pass rating, these directives could include specific changes in the oil spill

response plan, remedial training for response personnel in specific areas, or conferences with the Oil

Spill Program Administrator and other appropriate officials. After these directives are accomplished,

the GOMR will re-drill the operator to determine if he can now carry out an adequate response. Any

operator receiving a Fail rating may be subject to receiving Incidents of Non-Compliance (INC' s)

and civil penalties.

A few statistics regarding the GOMR Unannounced Oil Spill Drill Program:

Of the approximately 155 oil spill response plans currently on file with the GOMR,

approximately 130 candidates for the drills under the Unannounced Oil Spill Drill Program

are OCS oil and gas operators and 25 candidates are pipeline ROW holders.

There have been 55 unannounced drills since 1989.

a. Three of those were joint drills with the TGLO
13

One was a joint drill with the LOSCO

Thirty-nine have been table-top drills.

Sixteen drills involved mobilization of equipment.

3. There has been only one Fail rating given. (The operator who received this rating has since

been re-drilled, and the GOMR has determined that he is now capable of carrying out an

adequate oil spill response. The operator received a Pass rating in all three categories.)

Prior to the establishment of the GOMR Oil Spill Program Administrator position in November

1997, the GOMR averaged approximately six unannounced oil spill drills per year in keeping with

the May 1989 LTL announcing the Unannounced Oil Spill Drill Program. However, in 1998 the

GOMR has conducted 15 drills and has plans to average about 20 drillsper year in the future.

Please contact Mr. Rusty Wright, the MMS GOMR Oil Spill Program Administrator, for any further

information regarding the GOMR Unannounced Oil Spill Drill Program. He can be reached at

Minerals Management Service, Gulf of Mexico OCS Region, Plans Section, MS 5231, 1201

Elmwood Park Blvd., New Orleans, Louisiana 70 123-2394, office telephone: (504) 736-2529, fax:

(504) 736-2960, E-mail address: Harold. Wright mms,gov.

Angie D. Gobert is a Staff Petroleum Engineer in the MMS's Gulf of Mexico OCS Region, Office

of Field Operations - Plans Section. She has worked in the Plans Section for 141/2 years. She is

primarily responsible for the approval of Plans of Exploration, Development Operations

Coordination Documents, granting Rights of Use and Easements; and coordinating waiver requests.

For the past nine years, she has been responsible for and involved with mafters related to oil spill

response. She has experience in reviewing and approving oil spill contingency plans and has assisted

in the inspection of oil spill cleanup and containment equipment. She has served on the MMS

Monitoring Team for approximately 30 of the 55 unannounced oil spill drills in the Gulf of Mexico

and has acted as the MMS Monitoring Team Leader for approximately 12 of them.
14

THE MINERALS MANAGEMENT SERVICE CUTTING

EDGE OIL SPILL RESPONSE RESEARCH

Mr. Joseph V. Mullin

Minerals Management Service

Engineering and Research Branch

ABSTRACT

The Minerals Management Service (MMS), is the principal U.S. Government agency funding

offshore oil spill response research. The MMS, a bureau of the Department of the Interior, maintains

a comprehensive Oil Spill Response Research program in support of oil spill prevention and

response. Through funding provided by MMS, scientists and engineers from the public and private

sectors worldwide are working to address outstanding gaps in information and technology

concerning the cleanup of oil spills. Joint research projects with Environment Canada (EC) continue

to focus on determining the physical and chemical properties of crude oil, the fate and behavior of

spilled oil, remote sensing and mapping of oil slicks, chemical treating agents including dispersants,

and innovative shoreline cleanup strategies. Injoint projects with the National Institute of Standards

and Technology (NIST), MMS continues to assess the capabilities of in situ burning as an oil spill

response tool. Also discussed is Ohmsett The National Oil Spill Response Test Facility Ohmsett

is the only facility in the world where government agencies, universities, and private companies can

conduct full-scale oil spill response equipment testing, research, and training with oil under

controlled conditions.

DISCUSSION

As the stewards of more than 1.4 billion offshore acres, the MMS is responsible for the

environmentally sound management of the nation's undersea mineral resources. These include

energy and other mineral resources on the Outer Continental Shelf (OCS). Through leases granted

by the federal government to private industry for exploration, development and production, the OCS

accounts for one-ninth of America's oil production and one-fourth of its natural gas production

(Labelle 1997).

For more than 20 years, MMS has maintained a comprehensive international research program to

improve oil spill response technologies and procedures. The MMS manages the Oil Spill Response

Research Program (OSRRP) as part of its Technology Assessment and Research Program (TARP).

Funds for the OSRRP are appropriated from the Oil Spill Liability Trust Fund (OSLTF). By making

payments into the fund, as required by OPA-90, companies that produce and transport oil are

supporting research to improve oil spill response capabilities. This paper has been prepared in an

ongoing effort to keep responders and decision makers informed on our recent findings.
PROPERTIES AND BEHAVIOR OF SPILLED OIL

The MMS has jointly ftmded the Catalogue of Crude Oil and Oil Product Properties with EC since

1989. The catalogue contains physical and chemical information on more than 380 different types

of crude oils and oil product properties. The current version online through EC's Internet web site

(http.'//www. etcentre. org/spills/). The catalogue contains many new data points including adhesion

measurements, evaporation equations, new form of distillation data, BTEX and C3 analysis, etc. It

is now possible to generate more than 800 data points for each oil.

The BOSSBehavior of Oil Spilled at Seaproject is designed to provide a comprehensive

collection and review of data arid ideas related to oil spill behavior. More than 6,500 scientific papers

have been collected and reviewed. Topics include behavior of oil spilled at sea but will also include

the lesser-documented topics of oil on land, on freshwater and oil in ground. A draft oil-in-ice

volume is complete and under peer review.

REMOTE SENSING AND SURVEILLANCE

Laser Fluoro sensors are active sensors, meaning they provide their own source of illumination arid

can therefore be used during the day or at night. Laser Fluorosensors detect a primary characteristic

of oil, namely their characteristic fluorescence spectral signature and intensity. The Laser

Environmental Airborne Fluorosensor (LEAF) was tested in two well-documented field trials and

several test flights along inland waterways including Chesapeake Bay. In the summer of 1996, the

LEAF participated in the recovery of the "Irving Whale" oil barge off the east coast of Canada

(Brown 1997). Knowledge and experience gained from operation of the LEAF system have been

applied to the design of the next generation laser fluorosensor. The new system, designated the

Scanning Laser Environmental Airborne Fluorosensor (SLEAF), will be a fully operational system

incorporating state-of-the-art laser and solid-state detector technologies. The SLEAF will provide

spill response personnel with real-time oil contamination location information as hard copymaps.

In 1998-99, work will consist of

Mounting of the SLEAF in an aircraft

Ground and flight tests of the prototype

Demonstration and ground-truthing of the fluoro sensor concept over known targets

OIL SPILL CHEMICAL TREATING AGENTS

Dispersants

The "swirling flask" test method for dispersant effectiveness was developed in this project. This test

method has been modified to move away from visible measurement techniques to a GC technique

(Fingas 1997). In the case of light and waxy oils, this technique improves accuracy by several orders

of magnitude. The "swirling flask" method has been adopted by the US Environmental Protection

Agency for use in testing products for inclusion in the revised National Contingency Plan. Testing

of new commercial and experimental dispersants will continue to be conducted.

15
16

Surface Washing Agents and Solidifiers

Tests for the effectiveness of Surface Washing Agents and Solidifiers have been completed. Surface

washing agents are those surfactant-containing agents used to clean beaches or man-made shore

structures. A test for these agents has been developed and used to test more than 100 commercial

products. Additional standardization of the test method will be conducted. New agents will be tested

by EC as they arrive. A test for the effectiveness of solidifiers has been developed and used to test

more than 28 commercial products.

Emulsion Breaking and Inhibition Agents

Work on developing a test for effectiveness will continue, but five tests are currently in hand. It was

found that the test was very complex to develop (work has gone on for the past six years) because

of the complexities of emulsions. Work is continuing on a test for emulsion stability. The new

methods test separately for effectiveness in both closed and open systems and for inhibition or

breaking.

Biodegradation Agents

Tests for these agents are being developed. In addition, several commercial products have been

developed with an interim test, and their results are consistent. A test for freshwater has been

published. This year's work will focus on salt water systems and starting development of a new soil

test.

SHORELINE CLEANUP

Svalbard Shoreline Project

The Svalbard Shoreline Field Trials are part of a series of studies in a long-term program to better

understand the behavior of oil on shorelines and apply appropriate response options. The Svalbard

Shoreline Field Trials, in combination with its partner, the Oil and Fines Interaction (OFI) Basin

Trials, are investigating both the effectiveness of mainstream in situ shoreline cleanup techniques

arid the natural processes for oil removal from shorelines, in particular by oil and fine particle

interaction. The 1997 Svalbard Shoreline Field Trials were highly successftilly. Oiling of the

shoreline, treatment of oiled plots, and four sampling periods went as planned. Three shorelines were

oiled and experimental plots were established within the continuous stretch of oiled shoreline at each

site. A total of 5500 L of oil were used and applied to a 3m wide swath in the upper intertidal zone.

Treatments were conducted a week after oiling and after wave and tidal washing and working of the

oiled zone. Treatments included in-situ tilling (mixing), sediment relocation to the lower intertidal

zone (surf washing) and application of fertilizers to enhance biodegradation. Early results look

excellent for the surf washing treatment. Oil removal effectiveness was visually obvious. Initial

results suggest that the addition of fertilizers (soluble and slow release) was successful in delivering

nutrients to the intertidal waters on the oiled beaches, and that these nutrients stimulated microbial
17

activity in the beaches. A 1998 summer sampling program is underway to determine changes in the

oil content of the sediments due to natural or enhanced methods.

IN SITU BURN RESEARCH

In situ burning is a response technique that has been rarely used at sea but has been used for many

years to cleanup oil spills on land. Results from the mesoscale burns in Mobile, Alabama (1991-94),

the Newfoundland Offshore Burn Experiment, and the Alaska Clean Seas, Emulsion Burn

Experiments, continue to indicate that burning is a rapid, effective and environmentally safe means

for removing large quantities of oil from the surface of the water. In public and government forums,

burning has become accepted as a first response method. However, questions remain about the

effects of in situ burning on both water and air quality.

Fire Resistant Boon Technology

Most plans for burns at sea call for a fire resistant boom to contain and thicken the oil during

burning. For the past two years MMS and the U.S. Coast Guard (USCG) have participated in ajoint

project to evaluate the performance of commercially available and prototype firebooms. Phase I

evaluated the oil containment and towing ability at OhmsettThe National Oil Spill Response Test

Facility in Leonardo, New Jersey. Phase II evaluated the firebooms for thermal stress and mechanical

performance when exposed to a liquid fuel fire in waves. These burn tests were conducted in a

specially designed tank at the USCG Fire and Safety Test Detachment, Mobile, Alabama.

Smoke Plume Dispersion Modeling

The MMS funded the NIST to develop the ALOFT (A Large Outdoor Fire plume Trajectory model)

model to compute and display smoke plume trajectories from in situ burning. The ALOFT smoke

transport model can predict time-averaged downwind concentrations of particulate matter from a

large fire. Two model versions now exist: the ALOFT-FT for flat terrain and ALOFT-CT for

complex terrain. Both the flat terrain and three-dimensional complex terrain versions are operational

on personal computers and both versions can accommodate multiple fire sources. Based on input

from users, several significant new features have been added, including a fuel property's database

that can be modified by the user, an optional user specified emission factors and the ability to specify

different wind fluctuations over water and land. This version has been distributed to the response

community and is available from the Internet.

LABORATORY TESTING TO DETERMINE OPERATIONAL PARAMETERS FOR IN SITU

BURNING OF UNITED STATES OUTER CONTINENTAL SHELF CRUDE OIL SPILLS

Six U.S. Outer Continental Shelf (OCS) crude oils were selected by the MMS regional offices and

subjected to a laboratory test program. Three oils were produced in the Gulf of Mexico (Amoco High

Island, Green Canyon, and West Delta), and three were produced offshore California (Carpenteria,

Santa Clara, and Santa Ynez). The objective was to determine the following:
18

The effects of evaporation and emulsification on the ignition of spilled oil;

The ability of commercially available emulsion breakers and alternative gelled fuel igniters

to extend the window of opportunity for ignition of emulsions;

The effects of wave action on the combustion of emulsion slicks and,

The likelihood of the residues sinking after efficient burns of thick slicks of crude oils.

A final report has been completed. This study has shown that in situ burning is not a suitable

response option for all crude oils. The stability of a water-in-oil emulsion and its response to

emulsion breakers is highly dependent on the properties of the oil. Only three of the more widely

available emulsion breakers were tested on the oils in this study. It is vital that other crude oils be

tested to establish a catalog of in situ burning properties.

OHMSETTTHE NATIONAL OIL SPILL RESPONSE TEST FACILITY

Ohmsett is The National Oil Spill Response Test Facility, in Leonardo, New Jersey, on the grounds

of Naval Weapons Station Earle Ohmsett is the only facility in the world where clients can conduct

full-scale oil spill response equipment tests with a variety of crude oils and refined petroleum

products. Equipment tests are conducted under controlled, reproducible conditions and include the

capability for variable, artificial wavemaking Ohmsett provides a unique facility to conduct tests

and develop new devices and techniques that detect, map, contain and clean up oil spills. Ohmsett

is available on a reimbursable basis for use by Government agencies, private industry and academia.

The primary feature of the facility is a pile-supported, concrete tank with a water surface 203 meters

(667 feet) long by 20 meters (65 feet) wide and with a water depth of 2.4 meters (8 feet). The tank

is filled with 9.84 million liters of crystal clear water. The tank can tow floating test equipment at

graduated speeds up to 3.3 meters/second (6.5 knots) for at least 40 seconds. The towing bridge is

equipped to lay oil on the surface of the water several meters ahead of the equipment being tested,

so that reproducible thicknesses and widths of test oils are achievable with minimum wind

interference.

In FY-96, eight tests totaling 114 days were completed. In FY-97, 15 tests totaling 91 days were

completed. Final reports are available on all test series conducted to date. During FY- 1997, Ohmsett

underwent a major repair and refurbishments program that upgraded the condition of the facility and

increased testing capabilities. Historically Ohmsett was used to test and evaluate mechanical oil spill

response equipment (booms and skimmers). Based on clients requests, MMS has expanded the

operations at Ohmsett to accommodate a broad spectrum of oil spill response technologies such as

temporary storage devices, remote sensors, and sorbents. The U.S. Navy and USCG routinely use

Ohmsett to train their response personnel using their own equipment, with oil, in calm and wave

conditions. In FY-98 an extensive testing schedule has been completed that included evaluation of

several boom and skimmer systems, tow force tests, decanting studies of temporary storage devices,

evaluation of different sorbent materials, high speed boom tests, and oil containment and tow tests

of five different firebooms.
REFERENCES

Brown, Carl B., Nelson, Robert D., Fingas, Mery F. 1997. Recovery of the Irving Whale Oil Barge:

overflights with the Laser Environmental Airborne Fluorosensor, Proceedings of the Twentieth

Arctic andMarine Oil SpiliProgram (AMOP) Technical Seminar, Environment Canada, Ottawa,

Ontario, PP1O15-1022.

Fingas, Mery F., Huang, Eleanore, Fieldhouse, Ben, Mullin, Joseph, 1997. The effect of energy,

settling time and shaking time on the Swirling Flask Dispersant Apparatus, Proceedings of the

Twentieth Arciic and Marine Oil Spill Program (AMOP) Technical Seminar, Environment

Canada, Ottawa, Ontario, PP54 1-550.

Labelle, Robert P., Mullin, Joseph V., and White, Amy. 1997. Oil spill research program - Minerals

Management Service, Proceedings of the Twentieth Arctic and Marine Oil Spill Program

(AMOP) Technical Seminar, Environment Canada, Ottawa, Ontario, PP 1305-1313.

19

Joseph W. Mullin is Program Manager for Oil Spill Response Research with the U.S Department

of the Interior, Minerals Management Service, Engineering and Research Branch. He is responsible

for analyzing Outer Continental Shelf oil spill response operations, advising on appropriate spill

response techniques and equipment, and for procuring and managing oil spill response contractual

research. Mr. Mullin represents MMS on several national and international committees that deal with

oil spill research. Mr. Mullin received both an A.S. and a B.S. in Oceanographic Technology from

Florida Institute of Technology.

AVAILABILITY AND CAPABILITIES OF "OHMSETT": THE NATIONAL

OIL SPILL RESPONSE TEST FACILITY

Mr. Michael B. Whitehead

Mr. William T. Schmidt

MAR, Incorporated

Diarnondhead, Mississippi

OHMSETT REFURBISHMENT ENHANCES FACILITY'S CAPABILITIES

Newly refurbished and filled with 2 6 million gallons of sparkling, clear water, the tank at Ohmsett,

the National Oil Spill Response Test Facility, is ready for the testing season. Ohmsett is the only

place in the world where full-scale oil spill response equipment testing, research, and training with

oil can be conducted in a marine environment under controlled conditions.
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The Ohrnsett facility is located on Sandy Hook Bay in Leonardo, New Jersey. Ohmsett has been

operated and maintained by MAR Incorporated under contract to the U.S. Minerals Management

Service (MMS), Department of the Interior since 1992.

Ohmsett is available to both the public and private sector for evaluation of oil response equipment

such as booms, skimmers, temporary storage devices, dispersants and for research in remote sensing,

oil characteristics, and controlled oil burns.

"The unique testing facilities at Ohmsett are essential if we hope to develop the technology and

procedures required to effectively respond to future oil spills," says Joseph Mullin, MMS Program

Manager for Oil Spill Response Research. "In the event of an oil spill, do we really want to rely on

equipment and techniques that have not been properly tested?"

Ohmsett's concrete tank measures 667 feet long and 65 feet wide, with a water depth of eight feet.

Conditions simulating actual spill situations can be created with the wave generating system and a

wave dampening artificial beach. Moveable bridges can tow equipment at speeds up to 6.5 knots.

Customers and technicians can view a test from the bridges or from the control tower above the tank,

while state-of-the-art data collection and video systems record test results.

Use of the Ohmsett facility is available on a reimbursable basis to both the private and public sectors

as a research center to test oil spill containment/clean-up equipment or techniques, remote sensing

devices or to conduct training in oil spill response. Current testing at Ohmsett is being funded by

MMS, U.S. Coast Guard, U.S. Environmental Protection Agency, Environment Canada, and the

Marine Spill Response Corporation.

Funding and imagination are the only limits to the oil spill response research opportunities at

Ohmsett. MMS stands ready to assist all public and private sector organizations in meeting their

goals of developing superior oil spill response capability. For more information contact:

Bill Schmidt, Ohmsett Site Manager

Box 473 Atlantic

Highlands, New Jersey 07716

Tel: 732-8667183, Fax: 732-866-7189

e-mail: ohrnsettprn@monmouth. corn

Joe Mullin, MMS Ohmsett Project Officer

Tel: 703-787-1556, Fax: 703-787-1555

FACILITY FEATURES AND CAPABILITIES

Ohmsett' s main feature is an aboveground concrete tank measuring 203 meters long by 20 meters

wide by 3.4 meters deep. The tank is filled with 9.84 million liters of brackish water from nearby

Sandy Hook Bay.

Michael Whitehead, Ohmsett Marketing

4313 Leisure Time Drive

Diamondhead, Mississippi 39525

Tel: 228-255-1461, Fax: 228-255-9320

email: wxwizz@aol.com
The main facility features and capabilities are as follows:

A main towing bridge capable of towing test equipment at speeds up to 6.5 knots;

An auxiliary bridge oil recovery system to quantify skimmer recovery rates;

A wave generator capable of simulating regular waves upto one meter in height, as well as

a simulated harbor chop;

A movable, wave-damping artificial beach;

An oil distribution and recovery system that can handle heavy, viscous oils and emulsions;

A control tower with a fully computerized 32-channel data collection system as well as

above-and below-water video;

A centrifuge system to recover and recycle test oil;

Blending tanks with a water and oil distribution system to produce custom oil/water

emulsions for testing;

A filtration and oil/water separator system;

An electrolytic chlorinator to control biological activity;

Permanent and mobile storage tanks that can hold over 227,000 liters of test fluids;

A vacuum bridge to clean the bottom of the tank; and staging and shop area for special

fabrication.

Through a variety of mechanical, electrical, and chemical systems at Ohmsett, the following test

parameters can be controlled or measured:

Sea state (wave height, length, and period);

Tow speed;

Meteorological data;

Water temperature and salinity;

Volume of oil encountered and recovered by test equipment or protocol;

Oil-water ratios;

Physical characteristics of experimental oil; and Behavior of treated oils.

SPILL SCHOOL NOW IN SESSION

A recently forged relationship with the National Spill School at Texas A&M University helps make

Ohmsett a premier training site for oil spill response personnel. The National Spill School is

recognized as the leading specialist in hazardous material spill training In 1997, instructors with the

National Spill School teamed up with Ohmsett to conduct training sessions at the facility.

Ohmsett has scheduled two training sessions with Texas A&M for the summer of 1998, and can

book more for public and private sector personnel. Another notable developmentpart of Ohmsett' s

recent refurbishment effortis the addition of a 30-seat classroom with an array of audiovisual

equipment. Students can receive classroom training and review and critique their videotaped

performance on equipment in the tank.

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Companies and agencies can also configure a training session to their own specific needs, using their

own equipment. Strictly hands-on training sessions are also available without the classroom portions

taught by Texas A&M.

The Coast Guard was first to take advantage of the opportunity to train with Texas A&M in July of

1997. Crew from buoy tenders WILLOW, JUNIPER, and KUKUI, and members of the Atlantic

Strike Team trained to operate the USCG Vessel of Opportunity Skimming System (VOSS).

The training included an eight-hour OSHA refresher course. Upon completion of the five-day course,

students received a certificate from the Texas A&M University National Spill Control School.

A valuable feature at Ohmsett is a half-hull that can be placed in the tank. The VOSS was placed

alongside the hull as it would be in actual use, and the crew practiced recovering oil under conditions

close to the real thing.

The Coast Guard returned in September 1997, when members of the Coast Guard Spill Response

Strike Team came for practice training The aim this time was to increase proficiency in use of a

fence boom and weir skimmer The recovered oil was collected and measured at each test and, by

the end of the week, students had a clear picture of how their performance had improved.

"They know how to use their equipment already," says Phil Coyne, Ohmsett Test Engineer. "But

they wanted to become more proficient at recovering oil. They wanted to practice. You can't rehearse

with oil in the ocean. You can use popcorn and other biodegradable substitutes, but oil is a fluid and

popcorn is a solid body and it behaves differently from oil. We plan to make spill training at Ohmsett

part of our schedule."

Also in September 1997, the Navy put a belt skimmer in Ohmsett's tank to train the Navy crew

charged with responding to oil spills in Sandy Hook Bay, New Jersey. After a half day of classroom

training, the crew practiced rigging their equipment in the tank and the next day began practice runs

recovering oil.

LT Chris Chadwick, NWS Earle Port Officer says, "Ohmsett is the only place I know of where you

can train with oil. You can train all you want using substitutes, but there is no substitute for real spill

experience."

LT Chadwick plans to send another group of Navy spill personnel to Ohmsett for two weeksand

maybe morein 1998. "The Navy has such a high turnover in personnel, you need to train

constantly," he says. "We plan to make spill training at Ohmsett part of our schedule."

For information on booking a training session date at Ohmsett, call Bill Schmidt at (732) 866-7183,

e-mail: ohmsettprn@rnonrnouth.com, or Michael Whitehead at (228) 255-1461, e-mail:

wxwizz@aol. corn.
TESTING VARIABLES AND MEASURED RESULTS

Ohmsett's size allows various oil spill recovery components (booms, skimmers, and temporary

storage devices) to be combined into systems that can be realistically evaluated and compared with

each other.

Testing Variables

Oil Viscosity Skimmer Testing Variables

Wave Conditions TSD Testing Variables

Boom Testing Variables Mechanical Geometry

Measured Results

First Loss Speed Oil Recovery Rate

Gross Loss Speed Tow Tension

Critical Speed Deployment/Retrieval Procedures

Ohmsett's size can also accommodate large full-scale skimmer systems that can be evaluated in a

real-life environment.

Testing Variables

Oil Viscosity Wave Conditions

Velocity through the Water Mechanical Geometry

Oil Encounter Rate & Volume Debris

Skimmer Speed

Measured Results

Oil/Water Volume Recovered Recovered Oil Characteristics

Oil Volume Recovered First Loss Speed

Water in Oil Gross Loss Speed

Oil Recovery Rate

Ohmsett's 203 m long x 20 m wide x 3.4 m deep tow basin allows full-scale evaluation of oil

containment booms using a wide range of oil viscosities. MMS has developed standard testing

protocols for comparative performance evaluations.

Testing Variables

Oil Viscosity Wave Conditions

Oil Volume Precharge Tow Carriage Speed

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Measured Results

Towspeed for First Loss

Towspeed for Gross Loss

Critical Speed and Failure

Wave Conditions

Ohmsett is an ideal facility to test and evaluate the practical effectiveness of Temporary Storage

Devices (TSDs).

Testing Variables

Oil Viscosity Percent Capacity Load

Oil Water Mixture Pump Configurations and Methods

Ratios Wave Conditions

Measured Results

Offloaded Volume

Pumping Rates

Effectiveness of Cleaning Methods

Ohmsett can realistically evaluate the relative response characteristics of oil spill detection devices

to a wide variety of controlled oil spills with known characteristics.

Testing Variables

Oil Viscosity

Emulsions

Surface Area and Thickness

Measured Results

Detector Response Profile

Meteorological Conditions

Tow Tensions

Above and Underwater Video

Water Temperature and Salinity

Meteorological Data

Wave Conditions

Detection Device Height over Water

Detector Velocity

Michael Whitehead is the Mississippi Group Manager and Principal Scientist for MAR,

Incorporated's Meteorology and Oceanography (METOC) Center in Diamondhead and the Major

Shared Resource Center located at Stennis Space Center, which supports the CRAY supercomputer

operations. He is MAR's Senior Operational Meteorologist, directing environmental and mapping

support of U.S. Navy missions, by providing detailed research studies and forecast products and

services in support of World-Wide Fleet Operations. He has spearheaded the effort to convert
25

traditional training materials into multimedia presentations and has expanded MAR' s capabilities

in the Geographic Information Services and the commercial weather arena. Before joining MAR,

Commander Whitehead completed a 23-year Navy career in Operational METOC Support,

concluding with ai assignment as the Director of Training for approximately 4,000 government

personnel. Commander Whitehead's academic background includes an M.S. in operations management from the University of Arkansas in Fayetteville and a B.S. in geography and meteorology from

the University of the State of New York in Albany. Michael is also an experienced Total Quality

Leadership Facilitator and is an American Red Cross-certified Community Disaster Education

Instructor. In 1998 MAR and the Mineral Management Service called on Michael to represent

Ohmsett as the facility's Marketing Coordinator.

William Schmidt is Program Manager at Ohmsett, The National Oil Spill Response Test Facility.

MAR, Inc., the contractor to the U.S. Department of the Interior, is responsible for running the

facility. Mr. Schmidt is responsible for the overall management and administrative responsibility for

ensuring Ohmsett is operated and maintained as an environmentally and physically safe and secure

facility. In addition, he is responsible for supporting and actively participating in marketing efforts

to attract and retain clients by developing a marketing plan and attending technical committee

meetings and conferences. 1-le also presides over the Health and Safety meetings. Mr. Schmidt

received a B.S. in engineering from the New Jersey Institute of Technology (1979).
SESSION lB

FISHERIES ASSOCIATIONS WITH PLATFORMS

Chair: Mr. Gregory Boland

Co-Chair: Dr. Ann Scarborough Bull

Date: December 8, 1998

Presentation Author/Affiliation

Cross-shelf Gradient of Larval Fish: Mr. James Ditty

Importance to Platform Productivity Dr. Richard F. Shaw

Ms. Talat Farooqi

Coastal Fisheries Institute

Louisiana State University

Importance of Zooplankton to Platform Mr. S.F. Keenan

Productivity Department of Biological Sciences

Louisiana State University

Dr. M.C. Benfield

Dr. R.F. Shaw

Coastal Fisheries Institute

Louisiana State University

Ms. H.L. Haas

Department of Oceanography and Coastal Sciences

Louisiana State University

Effect of Depth on the Density of Dr. David R. Stanley

Fishes at Three Petroleum Platforms Dr. Charles A. Wilson

Coastal Fisheries Institute

Center for Coastal, Energy and Environmental

Resources

Louisiana State University

Fisheries Impacts of Underwater Mr. Gregg Gitschlag

Explosives Used in Platform Salvage Galveston Laboratory

in the Gulf of Mexico 1993-1998 National Marine Fisheries Service

27
28

Presentation Author/Affiliation

Preliminary Surveys of Sessile

Invertebrate Community on a Partially

Removed Platform Reef off South

Padre Island, Texas

Preliminary Observations of Fish

Assemblages Associated with a

Partially Removed Platform off the

Texas Coast

Mr. Terry E. Riggs

Dr. Quenton R. Dokken

Mr. Carl R. Beaver

Center for Coastal Studies

Texas A&M UniversityCorpus Christi

Ms. Lisa D. Vitale

Dr. Quenton R. Dokken

Center for Coastal Studies

Texas A&M University-Corpus Christi
CROSS-SHELF GRADIENT OF LARVAL FISH: IMPORTANCE

TO PLATFORM PRODUCTIVITY

Mr. James Ditty

Dr. Richard F. Shaw

Ms. Talat Farooqi

Coastal Fisheries Institute

Louisiana State University

INTRODUCTION

The proliferation of offshore oil and gas structures (defacto artificial reefs) in the northern Gulf of

Mexico since the 1940's has undoubtedly affected the marine ecosystem. With relatively little natural

hard bottom, the introduction and structural complexity of nearly 5,000 petroleum platforms in the

northern Gulf of Mexico has substantially increased hard-bottom habitat, thereby attracting a variety

of reef and pelagic fishes to their reef-like structure. Since wetlands are nursery areas for a large

number of commercially and recreationally important fish, continual loss of estuarine and wetland

areas make knowledge of the potential nursery function of other habitats, such as artificial hardbottom, critical. As nursery areas, offshore oil and gas platforms may be similar to shallow, softbottom estuarmne wetlands in several important ways: 1) increased food availability; 2) potentially

lower predation pressure; and, 3) spatial or structural complexity of habitat (i.e. many ecological

niches, cnooks and crannies", and refugia). Thus, oil and gas platforms may serve as essential fish

habitat" for the early life history stages of a variety of reef and reef-associated fishes. Further-more,

since reef fish assemblages are among the most diverse and taxonomically rich in the aquatic

biosphere (Sale 1991), platform-associated communities may significantly enhance the biodiversity

of the northern Gulf and serve as a migratory route for exotic species. Our objectives were to

provide information on the nursery ground/refugia role of platforms for postlarval/juvenile fish;

respond to specific fisheries management requests for basic biological information on reef fish

seasonality and cross shelf distribution; and 3) begin cross-shelf characterization of the early life

stages of fish utilizing offshore petroleum platforms off central Louisiana.

METHODS

We conducted sampling over a three-year period (1995-1997) along a N-S cross-shelf transect of oil

and gas platforms off Louisiana to document the use of platform structure as nursery habitat by early

life stages of reef- and other structure-associated fishes. Sites differed in depth, cross-shelf location

(with differing exposures to nutrient-rich waters of the Mississippi River plume), and faunal

assemblage. During Year One (1995-1996), we sampled at Green Canyon 1 8A (GC 1 8A), a Mobile

oil and gas platform located in oligotrophic, shelf break waters 225-rn deep, located about 220-km

south of Morgan City. During Year Two (1996), we sampled at Grand Isle 94B (G194B), a Mobile

platform located in mesotrophic, mid-shelf waters 60-rn deep. During Year Three (1997), we

sampled at South Timbalier 54G (ST54G), an Exxon platform located off Grande Isle in turbid,

highly productive waters about 20-rn deep. We sampled monthly at GC1 8A around the new moon.

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G194B was sampled twice monthly (both new and fill moons) for three consecutive nights within

a five-day period between April and August, times coinciding with either peak spawning or

recruitment of most reef fish in the area. During May, however, we also sampled during both thefirst

and third quarter moon phases for two consecutive nights. The sampling design at ST54G was

similar to that at G194B except there was no extra May sampling during quartermoon phases. Each

set contained, when possible, a vertical plankton net tow (30-cm net, 0.063-mm mesh), surface and

at depth (about 20-rn) light trap samples within rig structure, a surface off-rig light trap sample, and

a horizontal plankton net tow (60-cm, 0.333-mm mesh, 15 mm duration) fished passively at the

surface and at depth (20-rn). Logistic constraints, weather, and gear failure resulted in restricted

sampling during some months. Light traps fished for 10 minutes. Off-rig light traps floated at least

15-20 m downstream before turning on the light. We collected hydrographic data (current speed and

direction, temperature, salinity, and turbidity) at each site, when possible. GC 1 8A has a primarily

tropical reef fish assemblage, G194B a brown shrimp faunal assemblage, and STS4G a white shrimp

faunal assemblage (Gallaway 1981).

RESULTS

The early life stages of fish collected at the various cross shelf sites closely approximate the adult

faunal assemblages of Gallaway (1981). Larval and juvenile stages of coastal pelagic (e. g.,

engraulids, clupeids, and planktivorous carangids) and demersal/estuarine species (e. g., sciaenids

and flatfishes) dominate catches at inner shelf ST54G. Catch per unit effort (CPUE) of reefassociated taxa (e. g., blennies, gobies, and snappers), predatory ocean pelagics (e. g., jacks, blue

runner, most tunas and mackerels) and demersal/pelagic fishes (e. g., lizardfish) are greater at G194B

than either ST54G or GC 1 8A, with CPUE generally low in all ecological-categories at GC 1 8A

(Figure 1B.1). Relatively abundant reef-associated species at G194B include: vermilion snapper

(Rhomboplites aurorubens) and snappers of the genus Lutjanus spp., several members of the family

Blennidae, and various sea basses and groupers.

CPUE differed among sites and gear. Overall, catches were higher in surface light traps fished within

rig structure than in traps floated away from the rig, while light traps fished at 20-rn had the lowest

CPUE. Occasionally, standardized catches in surface plankton nets were up to 5-10 times higher

than in light traps. These high plankton net catches may be due to differences in gear selectivity

and/or the differential mortality experienced by the larger specimens selectively captured by light

traps. Differences in length frequencies of taxa caught with each gear support this observation.

Plankton nets generally collect larvae <6 mm standard length (SL) whereas light traps generally

collect fish >5 mm SL.

Preliminary analyses suggest that CPUE at ST54G was greater on the full than new moon. At G194B,

however, both density estimates from surface plankton nets and CPUE from light traps suggest

higher catches during the first quarter moon. However, differences between sites and betweenmoon

phases may be taxa-dependent. Data also suggest that CPUE are generally higher when currents are

toward the west and north than towards the south and east. Furthermore, CPUE is generally higher

before than after midnight.
Figure 1B.1. Catch per unit effort (CPUE) by gear type and rig along a cross-shelf transect in the Gulf of Mexi

CP: coastal pelagic fishes; UP: ocean pelagic fishes; R: reef-associated taxa; and D/MP: demersal/
32

In summary, the early life stages of fish collected at the various cross shelf sites closely approximate

the adult faunal assemblages of Gallaway (1981). We collected larvae/juveniles of most reef and

reef-associated taxa known to frequent rigs arid suggest that some reef fishes use oil and gas

platforms as nursery areas. Because ocean pelagic and demersal/pelagic predators are abundant at

all three rigs, predation pressure is probably high. Finally, light traps appear to effectively

characterize most coastal pelagic, ocean pelagic, and some reef fishes that use petroleum platforms

off Louisiana.

REFERENCES

Gallaway, B. J. 1981. An ecosystem analysis of oil and gas development on the Texas-Louisiana

continental shelf. U. S. Fish and Wildi. Serv., Office Biol. Serv., Washington, D. C., FWS/OBS8 1/27, 89 pp.

Jim Ditty has conducted fisheries research in the Gulf of Mexico for 20 years, the past 12 at LSU's

Coastal Fisheries Institute, and has authored over 20 articles on the taxonomy and ecology of larval

and juvenile fishes. He now manages the Taxonomy and Ecology Lab for the Fish Ecology Section

at NMFS's Galveston Lab, Texas. He received his B. S. in zoology from Marshall University, his

M. S. in marine fisheries from LSU, and is currently a Ph.D. candidate in Biological Oceanography

atLSU.

Richard Shaw is the Director of the Coastal Fisheries Institute and a Professor in the Department of

Oceanography and Coastal Sciences at LSU. He has worked with ichthyoplankton since 1973 and

received his Ph.D. in biological oceanography from the University of Maine at Orono in 1981.

Talat Farooqi is a Research Associate at the Coastal Fisheries Institute. She has worked with

ichthyoplankton from the Gulf of Mexico since 1985. She received her M. S. in marine biology from

the Institute of Marine Biology, Karachi, Pakistan.
IMPORTANCE OF ZOOPLANKTON TO PLATFORM PRODUCTIVITY

Mr. S.F. Keenan

Department of Biological Sciences

Louisiana State University

Dr. M.C. J3enfield

Mr. R.F. Shaw

Coastal Fisheries Institute

Louisiana State University

Ms. H.L. Haas

Department of Oceanography and Coastal Sciences

Louisiana State University

ABSTRACT

The source of productivity that sustains the high numbers of fishes associated with petroleum

platforms remains a poorly understood question. Recent studies on the feeding ecology of blue

runner Caranx crysos suggest that zooplankton form a substantial portion of the diet during earlymid summer. The dominant zooplarikton in the diets of these highly abundant fishes are

predominantly pelagic marine taxa. We suggest that the combination of artificial illumination and

modification of the hydro dynamic flow field by the platform structure favor the accumulation of

large numbers of oceanic zooplankton. The artificial illumination also allows nocturnal feeding by

visual predators such as blue runner. This subsidy of zooplankton may provide an important link in

the food web at offshore platforms.

INTRODUCTION

Approximately 5,000 offshore petroleum platforms exist in the Gulf of Mexico (Reggio 1996). In

the northwest Gulf of Mexico, these structures provide the vast majority of hard substrata available

to sessile organisms. Fouling genera established on the platform substructure thrive in nutrient-rich

waters of the northern Gulf and form reef-like communities. This unique existence of hard substrata

found in open ocean environments has been termed vertical benthos.

Increased concentrations of pelagic and demersal fish species are found in proximity to platforms.

Flow these populations are sustained remains an important question in developing strategies for

deconmiissioning platforms. Successful rigs-to-reefs programs in Louisiana and throughout the Gulf

of Mexico rely on converting these decommissioned structures into productive artificial reef

communities. A critical component of a sound rigs-to-reefmanagement strategy is an understanding

of the trophic ecology of rig communities.

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Our study coincided with research conducted by theLSU Coastal Fisheries Institute on recruitment

periodicity, growth and mortality ofpre- and post-settlement juvenile fishes at offshore petroleum

platforms. Fortnightly sampling trips were made for this MMS-ftmded project which utilized surface

and subsurface (20m) plankton net tows, and light traps deployed beneath and downstream from the

platforms.

In May 1996, a single blue runner Caranx crysos (Cararigidae) was collected by hook and line at

(G194B) a mid-shelf platform. The stomach of this fish was full of hyperiid amphipods, small

crustaceans that were highly concentrated in the plankton samples from that evening. The

phenomenon of a medium sized (25 cm. SL) schooling, pelagic fish consuming relatively small (2-5

mm.) zooplankton suggested a trophic linkage between the platform and the surrounding fish

community. This led to a LSU Sea-Grant Undergraduate Research Opportunities Program

investigation of the relationship between secondary zooplaakton productivity and the C. crysos

populations at G194B.

Little is known about the behavioral changes that pelagic zooplanktonundergo when they encounter

a platform or other structure. We set forth two hypotheses to explain mechanisms for zooplankton

association with these structures: (1) hydrodynamic entrainment; and (2) phototaxis. Large amounts of flotsam were observed beneath the platform, suggesting the formation of eddies due to

interactions between the platform and the currents. These eddies could also lead to hydrodynamic

entrainment of plankton. Additionally, many of the zooplankton collected, including hyperiid

amphipods, decapod/stomatopod larvae, and copepods, are attracted to light fields. At night, the

platforms illuminate the surrounding waters, which may attract positively phototaxic zooplankton.

The objectives of our study were to: (1) determine ifhyperiid amphipods and other zooplankton were

important in the diet of C. crysos; (2) compare species composition of prey items in fish guts with

concentrations in the environment; and (3) determine if platforms serve to increase concentrations

of prey items beneath the structure relative to downstreamwaters.

METHODS

Mobil's Grand Isle 94B platform (28.5267°N, 90.0983°W) served as the location of our study. Blue

runner feeding data was collected during three sampling trips on 28-30 June, 28 July -1 August, and

12-15 August 1996. Hook and line collections using artificial lures were made opportunistically. Mass, length, sex and time of capture were recorded for each fish. The stomach contents were

preserved in ethanol for subsequent examination and identification of contents. Nocturnal light traps

and 60 cm. diameter plankton nets (335 tm) alternated in deployment as part of the MMS-funded

ichthyoplankton research. We attempted to assess the potential for entrainment and phototaxis in

evening zooplankton concentrations by comparing the catch per unit effort (CPUE) of animals in

light traps beneath arid downstream from the platform. The attractive qualities of the lighted

platforms are tested by viewing the amphipod concentrations in light traps over time.

In the laboratory, stomach contents and plankton samples were divided into the following taxonomic

groups: hyperiid amphipods, decapod/stomatopod larvae, copepods, chaetognaths, fish, fish eggs, other invertebrates, and other material. Displacement volumes for prey items were measured to
35

compute gut fullness for each animal Plankton densities, computed from plankton net tows, along

with stomach content results were used to form electivity indicies. To determine whether blue runner

were actively selecting for specific prey items, we employed Ivlev's electivity index:

E = -

r + p

where r1 represents the numerical proportion of prey item i found in the gut and p. the relative

abundance of the same prey item in the environment (Ivlev 1961).

RESULTS

A total of 40 blue runner (including the fish captured on 19 May) were collected from near surface

waters. The fish ranged in size from 24.5 - 42.5 cm. SL, indicating all were at or approaching sexual

maturity. Peak catches occurred at 1 ,200h, 2,000-2,1 OOh, and 0,1 OOh. Gut fullness data suggest blue

runner feed during the night and around mid-day (Figure 1 B.2)

Zooplankton comprised a large numerical fraction (80-100%) of stomach contents of blue runner in

May (initial fish), June and July with a shift in diet towards fish during August (Figure 1B.3). See

Benfield, et al. (1996) for a further description ofgut content data.

Electivity results were estimated for fish taken during the 28-30 June trip, because that was when

the majority of fish (63%) were collected. Electivity indicies require both gut and environmental

abundance data. Plankton sampling was only conducted at night. Thus, only nocturnal electivities

could be estimated. Selection for amphipods and decapods was positive while copepods display

negative selection.

Hyperiid aniphipod concentrations are significantly greater (p<0.006) beneath the platform compared

to downcurreni (Figure 1 B.4). Similar trends, although not significant, were suggested for decapodjstomatopod larvae, and copepods. Increases in the CPUE of amphipods over a three-hour period beneath the platform with concurrent decreases in the CPUE from off-platform traps were

observed (Figure 1B.5).

DISCUSSION

Zooplankton comprised a large proportion of the diet of blue runner at G194B during summer; however, they appear to be a seasonal forage supply. That hyperiid amphipods do not continue as

a dominant category in the diet may be due to a general decline in the abundance of these

zooplankton in the water column. Amphipod abundance from plankton sampling appeared to be at a maximum during May samples and decreased during the rest of the study (Benfield). The seasonal

shift in dietary preference may also have contributed to the change in prey. The early-midsummer

utilization of zooplarikton may also have been due to the paucity of suitable sized fish prey until the

summer.
6 F 'B' 10' 12' 14' '16 118 Sampling Intervals (h) Figure 1B.2. Mean gut fullness ± standard error of blue runner collected at G194B during June and July.
Numerical Propofflons (Volume/nc Fropornons Mayl9(n=1) June2B-30(n24) Ju1y29-31 (n=3) Aug 13-15(n=

Figure 1 B.3. Numerical (upper row) and volumetric contributions (lower row) of prey items in the diet of blue 

sampling trips to G194B during 1996. AMPHIPODS DECAPODS& STOMATOPODS FISH CHAErOGNATI-IA OTHER INVERTS UNIDENTIFIED MATERIA

EGGS COPEPODS
500 400 300 200 Q. 100 0 0 p=0.006 p=0.18 p=0.10Surface Off-Rig Figure 1B.4. Catch per unit effort (CPUE) ± standard error of hyperiid amphipods, decapod/stomatopod crustace

in surface samples directly beneath G194B and off-rig samples located downstream from the platf

Hyperiid Decapod5 Copepods Amphipod5 610 matopods
Figure 1 B.5. Time series ofhyperiid amphipod catchper unit effort (CPUE) beneath G194B from 23:20 to 02:14 i

rig samples.
40

The unidentifiable material found in the stomachs of the fish may have been fish remains. Digestion

rates increase in the warm waters of the Gulf, which could have made the material difficult to

identify. The absence of scale or bone remnants suggests that the material was not of fish origin.

Even if the material is from fish, on a volumetric basis, zooplankton comprised approximately half

the gut contents. Zooplanktivory by blue runner has been reported by Randall (1967), who noted that

the gut contents of two medium-sized fish (22 and 23 cm FL) consisted of 40 % planktonic

organisms."

A trophic linkage between the platform and pelagic species cannot be confirmed solely by the

presence of zooplankton in the diet of blue runner. Most of the zooplankton in the diet were from

holoplanktonic or meroplanktonic groups. Our primary taxonomic group of interest, hyperiid

amphipods, however, is known for its association with structure, in the form of gelatinous

zooplankton commonly used as hosts. The manner at which amphipods and other zooplankton may

react to structure in the pelagic environment is unknown.

One explanation for these dense aggregations beneath the platform is the interaction of the structure

with the prevailing currents. The complexity of the platform casing decreases current velocity

and creates eddies, which accumulate flotsam. This hydrodynamic effect may contribute similar

influences to plankton species. Our results indicate that hyperiid amphipods, and potentially

other zooplankton, are found in greater numbers beneath the platform than are found in downstream

sites.

Another testable hypothesis may explain increased concentrations of zooplankton around platforms.

Manned platforms produce light that is bright enough to cast a clearly visible field into the

surrounding water. The attraction of zooplankton and fish to light is well cited and is the principal

reason behind our use of light traps. Zooplankton may actively swim to maintain position in the light

field. As currents bring more plankton through the structure, concentrations should increase. Support

for this theory comes from our time series analysis of light trap CPUE.

Regardless of the process by which planktonic taxa accumulate beneath the platform, the elevated

concentrations of prey beneath G194B at night provide blue runner with an enhanced prey density

while the artificial light permits an extended foraging period.

While the attraction-production issue remains under investigation, our study identified a potential

linkage between structure and enhanced secondary production. Through physical or attractive means

the platforms appear to aggregate prey items that enhance productivity. Further investigations into

this interaction should include quantitative sampling of zooplankton, during day and night, both

beneath and upstream of the platforms. The influence of light on attraction could be tested by

comparing plankton samples from both manned (lighted) and unmanned platforms. Finally,

documenting the food habits of pelagic species will require year-round sampling with larger numbers

of replicate specimens.
REFERENCES

Benfield, M.C., Shaw, R.F. and Keenan, S.F. 1996. Importance ofzooplankton secondary production

to fishes at offshore petroleum platforms. In: Proceedings: Sixteenth Annual Gulf of Mexico

Information Transfer Meeting. Dec. 1996. New Orleans, LA. pp.220-227.

Ivlev, V.S. 1961. Experimental Ecology of the Feeding of Fishes. New Haven, Yale University

Press.

Randall, J.E. 1967. Food habits of reef fishes of the West Indies. Studies in Tropical Oceanography.

Miami no. 5: 745-746.

Reggio, V.C., Jr. 1989. Petroleum structures as artificial reefs: a compendium. Fourth International

Conference on Artificial Habitats for Fisheries, Rigs-to-Reefs Special Session, 4 November

1987. Miami, FL. OCS study/MMS 89-0021. l76pp.

Reggio, V.C. 1996. Decommissioning and artificial reef development. In: Proceedings: Sixteenth

Annual Gulf of Mexico Information Transfer Meeting. Dec. 1996. New Orleans, LA. pp. 3-4.

EFFECT OF DEPTH ON THE DENSITY OF FISHES

AT THREE PETROLEUM PLATFORMS

Dr. David R. Stanley

Dr. Charles A. Wilson

Coastal Fisheries Institute

Center for Coastal, Energy and Environmental Resources

Louisiana State University

INTRODUCTION

The largest artificial reef complex in the world, although unplanned, is composed of the 4000

petroleum platforms scattered across the outer continental shelf (OCS) of the northern Gulf of

Mexico (GOM). Scientists have hypothesized that artificial reefs and platforms improve andlor

diversify habitat, increase resources, modify the assemblages of organisms in the region or

concentrate existing resources. The placement of these defacto reefs has undoubtedly impacted the

regional marine community although little information is available. Only recently have assessment

methods been developed to test these arid other hypotheses concerning artificial reefs.

Since the first petroleum platform was placed off the Louisiana coast in 1948, they have been the

preferred destination of commercial and recreational anglers. Past research has found that platforms

were the destination of 70% of all recreational angling trips in the Exclusive Economic Zone (Reggio

1987). The high documented catch rates and the popularity with user groups in the region make

41
42

platforms an important component in the regions fisheries. Despite the number of sites, the longevity

of the structures and their importance to the regions fisheries little information exists on the

assemblage of fishes associated with petroleum platforms. Research projects at petroleum platforms

did not start until the late 1970's. They consisted of visual surveys conducted by SCUBA divers,

remotely operated underwater vehicles (ROY) and stationary cameras; the majority of these projects

were short term, often only "snapshots" of the fishes at each site (Sonnier et al. 1976; Gallaway et

al. 1981; Continental Shelf Associates 1982; Gallaway and Lewbel 1982; Putt 1982). The results of

this early research provided insights into the structures associated assemblages as abundance and

species composition varied with platform, water depth and time of the year and results have been

difficult to compare due to problems with limited visibility, gear bias, diver avoidance anda lack of

standardized survey methodology.

In response to the difficulty in assessing the fisheries resources associated with petroleum platforms

and the bias's inherent with visual surveys. Gerlotto et al. (1989) demonstrated that towed

hydroacoustics could be used to measure fish density near petroleum platforms off Cameroon. We

later utilized complimentary sampling methods of visual surveys and quantitative dual beam

hydroacoustic surveys to document the assemblage of fishes associated with petroleum platforms

in the northern Gulf of Mexico (Wilson and Stanley 1991; Stanley and Wilson 1995; 1996; 1997,

in press). Despite the range of methodologies, investigators found that fish abundance and species

composition change dramatically with proximity to platform, location, and time of year (Sonnier

1976; Continental Shelf Associates 1982; Gallaway and Lewbel 1982; Putt 1982; Stanley and

Wilson 1996; 1997; in press).

The objectives of this research were to use dual beam hydroacoustics to measure the density of fishes

associated with three petroleum platforms off the Louisiana coast. The goals of this research were

to determine the effect of water depth on fish density at platforms in 22, 60 and 219 m of water and

ultimately measure the fisheries value of platforms of different depths in the same geographical

region.

METHODS

This research project was designed to sample platforms in three water depths (shallow-shelf (South

Timbalier 54, ST54, water depth 22m), mid-shelf (Grand Isle 94. G194, water depth 60m) and

continental slope (Green Canyon 18, GC1 8, water depth 219m) across the Louisiana shelf. The

platforms were selected to approximate a transect extending offshore from Fourchon LA, 5T54 was

24 km southwest, G194 was 54 km south and GC 18 was 179 km southwest from the port.

Two arrays of stationary dual beam hydroacoustic equipment developed through our past research

were used to determine the density of fishes associated with the study sites (Wilson and Stanley

1991; Stanley and Wilson 1995; 1996; 1997; in press). Arrays 1 and 2 were designed to measure in

situ target strength distribution and density of fishes immediately adjacent to each side of the

platform. Array 1 consisted of four upward oriented transducers (120 kHz) suspended approximately

25 m below the surface (at ST 54 they were placed on the bottom), one on each side of the platform.

The upward facing transducers provided acoustic coverage from the surface to a depth of 10-15 m.
43

Array 2 consisted of four downward oriented transducers (120 kHz) placed approximately 3 m below

the surface, one on each side of the platform. The downward facing transducers provided acoustic

coverage from a depth of 10 m to 1 - 5 m from the substrate depending on the site. The use of four

transducers (both upward and downward orientations) enables the calculation of density throughout

the water colunm on all sides of the platform.

Acoustic sampling was conducted over consecutive 24 hour intervals for each sampling trip; two

hours of hydroacoustic data were collected encompassing four periods (dawn, noon, dusk and

midnight) over each 24 hour interval. Hydroacoustic data were collected sequentially from each

of the transducers in five minute intervals for each trip. Acoustic data were collected using a

Biosonics model ES2000 scientific echosounder/multiplexer-equalizer and see Stanley and Wilson

(1995; 1996; 1997; in press) for details on acoustic parameters and a more detailed desrciption of

methods.

Fish density data (number of fishm3) from echo integration analysis contained a large number of

zero values, similar to catch data from traditional fisheries sampling techniques (Pennington 1983;

1985; Shaw etal. 1985; Stanley and Wilson 1995; 1996; 1997; in press). Therefore, hydroacoustic

density data were transformed by log(density + 1) to approximate the normal distribution. Separate

randomized block ANOVAs using SAS (1986) GLM procedures were performed with vertical

log(density + 1) density data for each site on depth, side and the interaction of side* depth. Tukeyts

studentized range tests (Ott 1982) were used to compare the means of significant variables for

vertical and horizontal analyses. Tests were reported as significant at the alpha 0.01 level.

RESULTS

Fish density varied with platform side, depth and the interactions of depth* side at ST54 (Table

1B.1). Significantly higher densities were found on the north side of the platform than all others

(Figure 1B.6). With respect to depth, densities were significantly higher in the upper 10 m of the

water column than all other depth strata, although an increase in density from 20-22 m was also

observed but it was not significant (Figure 1 B .7). While the interaction of depth* side was significant

At G194 fish density varied with platform side and depth (Table 1B.2). Significantly higher densities

were found on the north and west sides of the platform than all others while lowest densities were

found on the east side of the platform (Figure 1B.6). With respect to depth, densities varied

significantly with depth and were significantly highest near the bottom, than immediately adjacent

to the surface and mid depth (Figure 1 B .7). The interaction of depth* side was significant the trend

of highest abundances near the surface and the bottom was consistent on all sides of the platform but

differences in densities between sides were observed (Table 1B.2).

Densities of fishes at the GC 18 production platform were highly variable over the study period

ranging from 0 to over 1.44 fishlm3. Spatially fish density varied with platform side, depth and the

interaction of depth'platform side (Table 18.3). Significantly higher densities were found on the

west side of the platform than all others, while densities were not significantly different on the north

and south sides (Figure 1B.6). Densities on the east side were five to eight times less than those on
44

Table 18.1. Randomized block design ANOVA (block on platform side) of log fish density data

(log (number fish * m3)) from South Timbalier 54 with platform side, depth and the

interaction of depth and side.

Table 1B.2. Randomized block design ANOVA (block on platform side) of log fish density data

(log (number fish * m3 )) from Grand Isle 94 with platform side, depth and the

interaction of depth and side.

Source DF SS MS F Prob> F

Model 19 23.81616337 1.25348228 13.16 0.0001

Error 2365 225.25333370 0.09524454

Corrected Total 2384 249.06949707

R-Square C.V. Root MSE LDENSITY Mean

0.095621 145.0434 0.3086171 0.2127757

Variables DF Type I SS Mean Square F Value Pr> F

Side 3 13.09084337 4.36361446 45.81 0.0001

Depth 4 6.40854576 1.60213644 16.82 0.0001

Side * Depth 12 4.31677424 0.35973119 3.78 0.0001

Variables DF Type III SS Mean Square F Value Pr> F

Side 3 12.08934034 4.02978011 42.31 0.0001

Depth 4 5.82590975 1.45647744 15.29 0.0001

Side * Depth 12 4.31677424 0.35973119 3.78 0.0001

Source DF SS MS F Prob> F

Model 47 157.11677757 3.34291016 22.42 0.0001

Error 8890 1325.7941409 0.14913320

Corrected Total 8937 1482.9109184

R-Square C.V. Root MSE LDENSITY Mean

0.105952 127.0847 0.3861777 0.3038743

Variables DF Type I SS Mean Square F Value Pr> F

Side 3 57.41183015 19.13727672 128.32 0.0001

Depth 11 81.51039732 7.41003612 49.69 0.0001

Side * Depth 33 18.19455010 0.55135000 3.70 0.0001

Variables DF Type III SS Mean Square F Value Pr> F

Side 3 58.41688848 19.47229616 130.57 0.0001

Depth 11 81.30836301 7.39166936 49.56 0.0001

Side *Depth 33 18.19455010 0.55135000 3.70 0.0001
45

Table 1B.3. Randomized block design ANOVA (block on platform side) of log fish density data

(log (number fish * m3 )) from Green Canyon 18 with platform side, depth and the

interaction of depth and side.

other sides of the platform (Table 18.3, Figure 1B.6). The most dramatic results of the research was

the relationship between fish density and depth. A significant and spectacular drop in density with

depth was observed at GC18 below lOOm (Table 1B.3, Figure 1B.8). Fish densities from 0 - 15 m

were significantly higher than all other depth strata and were 4 to 68 times higher than all other

depths (Figure 1 B. 8). Densities from 15 to 95 m were not significantly different but were 3 to 12

times higher than depths from 115 to 210 m (Figure 1B.8). From 115 to 210 m fish density was less

than 0.002 fishlm3, essentially zero, and lower than densities measured on the continental shelf of

the open waters of the Gulf of Mexico (Figure 1B.8). The interaction of depth*side was significant

the trend of highest abundances near the surface and decreasing with depth was consistent on all

sides of the platform but differences in densities between sides were observed (Table 1B.3).

DISCUSSION

This study again demonstrates the utility of merging hydroacoustics and visual survey techniques

to study the assemblage of fishes associated with petroleum platforms. The combination of these

techniques allows for the measurement of the area of influence of these defacto artificial reefs,

estimates of abundance, size distribution and species composition throughout the water column and

over long time periods.

Our results emphasize the variability in the density of fishes associated with petroleum platforms

especially with respect to depth and side. Similar results from this project and our earlier research

Source DF SS MS F Prob > F

Model 43 2.19861886 0.05fl3067 51.10 0.0001

Error 7738 7.74271777 0.00100061

Corrected Total 7781 9.94133663

R-Square C.V. Root MSE LDENSITY

Mean

0.221159 296.1676 0.0316324 0.0106806

Variables DF Type I 55 Mean Square F Value Pr> F

Side 3 0.24722057 0.08240686 82.36 0.0001

Depth 10 1.51026045 0.15102604 150.93 0.0001

Side * Depth 30 0.44113784 0.01470459 14.70 0.0001

Variables DF Type III SS Mean Square F Value Pr> F

Side 3 0.22377102 0.07459034 74.54 0.0001

Depth 10 1.51920801 0.15192080 151.83 0.0001

Side * Depth 30 0.44113784 0.01470459 14.70 0.0001
46

Figure 1B.6. Estimated fish density (number of fish / m3) by platform side at petroleum platforms

Grand Isle 94 (G194), South Timbalier 54 (ST54) and Green Canyon 18 (GC18).
al1dSober

3)

!Pt Pefr01 PLit0

47
48

Figure 1 B .8. Estimated fish density (number of fish / m3) by depth at petroleum platform Green

Canyon 18 (GC18).

35

115

155

GC18

195

0 0.05 0.1 015 0.2 0.25 0.3 0.35 0.4

Fish Density (# I m3)
49

were found with respect to the variability of fishes with respect to side of the platform and depth at

the shallow site (Stanley and Wilson 1996, 1997). Before this research no project has examined the

relationship between depth and density at deeper platforms. The observation of consistently higher

densities on one or two sides of the platform is similar to our past research (Stanley and Wilson

1996, 1997). The highest densities typically found on the north side may be due to the increased

structural complexity from the well bay found at the north end of these structures. Since fish

abundance has been positively correlated with structural complexity at other artificial reefs this may

explain the increased densities on the north side of the structures (Shulman 1984, Hixon and Beets

1989).

The primary questions to be addressed by the research was the effect of depth on the fish density.

Similar results with respect to density and water depth were found for sites on the continental shelf:,

ST54 and G194, as highest densities were found adjacent to the surface and the bottom. These results

were similar to those of our earlier research (Stanley and Wilson 1995, 1996, 1997) and those of

Chang (1985), Shinn and Wicklund (1989) and Rooker et al. (1997). The most dramatic results of

the project was the change in density with depth at the site on the continental slope, GC 18. A

significant and striking decrease in fish density with depth was found and below 100 m as very low

fish densities fish densities were detected. Previous research supports these findings as species

richness in the Pacific was negatively correlated with depth, especially in tropical latitudes (Stevens

1996) and bottom trawl data from the shelf break in the Gulf of Mexico (water depth> 110 m)

documented the presence of69 species however, low abundances were found and few reef dependent

species were captured (Chittenden and Moore 1977). The concentration of fishes at GC18 near the

surface is reflected in the fact that 88% of the fishes were found in the upper 60m of the water

column. While near surface fish densities at GC 18 were significantly higher than those below 60 m

the densities were only one half to two thirds compared to sites on the continental shelf. The decrease

is likely due to the location of GC1 8 and its distance from the highly productive waters of the

Mississippi River. Both STS4 and G194 were regularly influenced by the highly productive waters

from the Mississippi River as reflected in the lower surface salinities observed at these sites. The

high salinities observed at GC 18 with varied little from surface to the bottom, indicative of low

productivity oceanic waters and the oligoltrophic conditions appear to be reflected in lower fish

densities even near the surface.

Comparison of results from this research with other petroleum platform studies from the northern

Gulf of Mexico revealed similarities and significant differences in density and abundance.

Comparison of acoustically derived estimates of density from our past research showed similar

density values with those from this project especially at ST54 and G194. Mean densities fromour

earlier work (Stanley and Wilson 1995, 1996, 1997) at a site in 24 m of water were 0.244 (+1- 0.062,

95% confidence interval) fishm3, while mean densities found during this project were 0.333 (+7-

0.034) fishm3 at ST54, 0.496 (+1- 0.0 17) fishm3 at G194 and 0.029 (+7- 0.003) fislrni3 at GC18.

With the exception of GC 18 these values are consistent with those from Putt (1982) for a platform

in approximately 22 m of water off the Texas coast and an order of magnitude higher than the results

of Continental Shelf Associates (1982) from four platforms in June 1980. Both Putt (1982) and

Continental Shelf Associates (1982) used visual surveys with Putt employing stationary cameras and
50

Continental Shelf Associates using a ROV for visual surveys. While the densities from previous

studies are comparable to those estimated from our earlier and current research using hydroacoustics;

the visual techniques utilized are of limited value in low visibility by the authors' admission their

conclusions are limited to characterizations of fish populations under high visibility conditions. The

densities found at platforms also are much higher than those from the open waters of the Gulf of

Mexico. Morgan (1996) acoustically measured fish densities in the open waters of the northern Gulf

of Mexico in 20 to 35 m of water on the continental shelf and found mean fish densities were

approximately 0.00 1 fishm3. Based on all the results to date it is apparent that large concentrations

of fishes are found around these structures in the northern Gulf of Mexico but the debate continues

as to the exact function of these structures on whether they increase productivity or attract existing

organisms.

The 4000 petroleum platforms in the northern Gulf of Mexico, provide an estimated 12 km2 of

additional hard substrate (Stanley 1997) to a ecosystem that is dominated by a mud/sand substrate

(Parker et al. 1983). The expansion of hard substrate habitat especially habitat in the upper water

column has undoubtedly changed the dynamics of energy flow and influenced the utilization of

marine resources in the region but has proved difficult to quantify the impact of these structures. In

response to the use of platforms by fishers in the region Louisiana and Texas created artificial reef

programs and the materials of choice are retired platfonnjackets (Wilson et al. 1986, Stephan et al.

1990). The standard deployment of these structures as reefs involves placing the jacket on its side.

However, this deployment minimizes vertical relief and if a platform such as GC 18 was deployed

in this maimer it would extend approximately 80 m off the bottom. Based on our results at the site

very few fishes would utilize the structure in this orientation and its value as an artificial reef would

be questionable. This project is the first demonstrating the importance of vertical relief in

maximizing the effectiveness of platforms as artificial reefs especially with respect to deep water

environments.

This research confirms the variability of fish assemblages associated with petroleum platforms and

reinforces the need to sample on each site and throughout the water column to obtain an accurate

estimate of fish abundance. This study continues to demonstrate the utility of merging hydroacoustics

to study the assemblage of fishes associated with petroleum platforms.

ACKNOWLEDGMENTS

The authors would like to thank Mobil USA Inc., Exxon Company USA, the Minerals Management

Service, and the Louisiana Department of Wildlife and Fisheries for supporting this research

program. We would especially like to thank the staff of the petroleum platforms South Timbalier 54,

Grand Isle 94, and Green Canyon 18 for their help and tolerance throughout the research project.

REFERENCES

Chang, K. 1985. Review of artificial reefs in Taiwan: emphasizing site selection and effectiveness.

Bull. Mar. Sci. 37:143-150.
51

Chiftenden, M.E. Jr. and D. Moore. 1977. Composition of the ichthyofauna inhabiting the 110 m

bathymetric contour of the Gulf of Mexico, Mississippi River to the Rio Grande. N.E. Gulf Sci.

1:106-114

Continental Shelf Associates. 1982. Study of the effect of oil and gas activities on reef fish

populations in Gulf of Mexico OCS area. OCS Report MMS 82-10. New Orleans, Louisiana.

US DOT, MMS, Gulf of Mexico OCS Region.

Gallaway, BJ., and G. S. Lewbel. 1982. The ecology of petroleum platforms in the northwestern Gulf

of Mexico: A community profile. USFWS Office of Biology Services, Washington, D.C. FWS

1OBS-82/27. Openfile report 82-03.

Gallaway, B.J., LR. Martin, R.L. Howard, G.S. Boland, and G.D. Dennis. 1981. Effects on artificial

reef and demersal fish and macrocrustacean communities. Pages 23 7-299 in B.S. Middleditch,

editor. Environmental effects of offshore oil production: The Buccaneer gas and oil field study.

Marine Science Volume 14. Plenum Press. New York, New York.

Gerlotto, F., C. Bercy, and B. Bordeau. 1989. Echo integration survey around offshore oil extraction

platforms off Cameroon: Observations of the repulsive effect on fish of some artificially emitted

sounds. Proceedings of the Institute of Acoustics (19):79-88.

Hixon, M.A. and J.P. Beets. 1989. Shelter characteristics and Caribbean fish assemblages:

Experiments with artificial reefs. Bull. Amr. Sci. 44:666-680.

Morgan, T.C. 1996. Hydroacoustic survey of fish distribution and abundance around an artificial reef

and a standing platform in the northern Gulf of Mexico. M.Sc. Thesis. Louisiana State

University. 26p.

Ott, L. 1982. An introduction to statistical methods and data analysis. 2nd edition. Duxbury Press.

Boston, MA. 774 p.

Parker, Jr., R.O, D.R. Colby and T.P. Willis. 1983. Estimated amount of reef habitat on a portion

of the U.S. South Atlantic and Gulf of Mexico continental shelf. Bulletin of Marine Science

33 :935-940.

Pennington, M. 1983. Efficient estimators of abundance for fish and plankton. Biometrics 39:281-

286.

Pennington, M. 1985. Estimating the relative abundance of fish from a series of trawl surveys.

Biometrics 41:197-202.

Putt, Jr., R.E. 1982. A quantitative study of fish populations associated with a platform within

Buccaneer oil field, northwestern Gulf of Mexico. M.Sc. Thesis. Texas A&M University.

College Station, Texas.
52

Reggio, V.C. Jr. 1987. Rigs-to-reefs: the use of obsolete petroleum structures as artificial reefs. OCS

Report/MMS87-0015. New Orleans, LA. U.S. Department of Interior. Minerals Management

Service. l'7p.

Rooker, J.R., Q.R. Dokken, C.V. Pattengill and G.J. Holt. 1997. Fish assemblages on artificial and

natural reefs in the Flower Garden Banks National Marine Sanctuary. Coral Reefs. 16:83-92.

SAS Institute Incorporated. 1986. SAS user's guide: Statistics. Version 6. SAS Institute. Cary, NC.

l290p.

Shaw, R.F., J.H. Cowan, Jr., and T.L. Tiliman. 1985. Distribution and density of Brevoortia

patronus (Gulf menhaden) eggs and larvae in the continental shelf waters off western Louisiana.

Bull. Mar. Sci. 36:96-103.

Shinn, E.A., and R.I. Wicklund. 1989. Artificial reef observations from a manned submersible off

southeast Florida. Bull. Mar. Sci. 44:1051-1057.

Shulman, M.J. 1984. Resource limitation and recruitment patterns in coral reef assemblage. J. Expt.

Mar. Biol. Ecol. 74:85-109.

Sonnier, F., J. Teerling, and H.D. Hoese. 1976. Observation on the offshore reef and platform fish

fauna of Louisiana. Copiea 1976: 105-111.

Stanley, D.R., and C.A. Wilson. 1997. Seasonal and spatial variation in abundance and size

distribution of fishes associated with a petroleum platform in the northern Gulf of Mexico.

Canadian Journal of Fisheries and Aquatic Sciences. 54:1166-1177.

Stanley, D.R., and C.A. Wilson. 1996. The use of hydroacoustics to determine abundance and size

distribution of fishes associated with a petroleum platform. International Council on the

Exploration of the Sea, Journal of Marine Science 202: 473-475.

Stanley, D.R., and C.A. Wilson. 1995. Detection of the effect of scuba divers on fish density and

target strength utilizing dual-beam hydroacoustics. Transactions of the American Fisheries

Society 124: 946-949.

Stanley, D.R., and C.A. Wilson. 1991. Factors affecting the abundance of selected fishesnear oil and

gas platforms in the northern Gulf of Mexico. Fishery Bulletin 89: 149-159.

Stephan, C.D., B.G. Dansby, H.R. Osburn, G.C. Matlock, R.K. Riechers and R. Rayburn. 1990.

Texas Artificial Reef Fishery Management Plan. Fisheries Management Plan Series Number 3.

Texas Parks and Wildlife Department, Coastal Fisheries Branch, 4200 Smith School Road,

Austin, Texas.

Stevens, G.C. 1996. Extending Rapoport's rule to Pacific marine fishes. J. Biogeogr. 23:149154.
53

Thorne, R.E., J.B. Hedgepeth and J.A. Campos. 1989. The use of stationary hydroacoustic

transducers to study die! and tidal influences of fish behavior. Bulletin of Marine Science

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Wilson, C.A., V.R. Van Sickle and D.L. Pope. 1987. Louisiana Artificial Reef Plan. Lousiana

Department of Wildlife and Fisheries. Bulletin 41. 13 Op.

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and gas structures. Pages 115-119 in M. Nakamura, R.S. Grove and C.J. Sonu, editors. Recent

advances in aquatic habitat technology. Southern California Edison Company. Environmental

Research Report Series 91-RD-19.

FISHERIES IMPACTS OF UNDERWATER EXPLOSIVES USED IN PLATFORM

SALVAGE IN THE GULF OF MEXICO 1993-1 998

Mr. Gregg Gitschlag

Galveston Laboratory

National Marine Fisheries Service

INTRODUCTION

There are approximately 4,000 oil and gas structures in the Gulf of Mexico. Federal regulations

require removal of platforms within one year of lease termination. About 100 removals occur each

year. Plastic explosives, primarily Comp-b and C-4, are used to sever structural members and well

conductors in about two-thirds of these removals while mechanical techniques are used on the

remaining third. Explosives are typically placed inside the hollow pilings and generally do not

exceed 50 lb in weight (Gitschlag & Herczeg 1994). Offshore platforms serve as excellent artificial

reef habitat that attract a vast array of marine life (Dugas & Fischer 1979; Hastings et al. 1976;

Lewbel et al. 1987; Scarborough-Bull 1989; Sonnier et al. 1976; Stanley & Wilson 1990). The use

of underwater explosives can severely impact fish and other marine life in close proximity to the

structure during the removal process. This report discusses preliminary results of assessments of

fishery impacts conducted at nine platform removals between August 1993 and July 1998.

METHODS

Prior to detonation of explosives, fish were captured, tagged and released alive at the study site. After

detonation, fish killed by explosives either floated to the sea surface or sank to the sea floor. To

estimate the number and species of fish fatally impacted by explosives we attempted to collect all

the moribund fish which floated up to the sea surface. Field personnel operating from inflatable boats

used dip nets to perform this task. Recovering dead fish from the sea floor was much more difficult

arid required SCUBA divers. Due to the large impact zone it was not feasible to attemptrecovery of
54

Under

platform

Transect

Circular survey

lOOm

50m

25m

Figure 1B.9. Final sampling design.

all moribund "sinkers." A sample of these "sinkers" was collected using three techniques: line

transect surveys, circular surveys, and sampling frames placed beneath the platform. To increase

efficiency, procedural modifications were made early in the study and only final sampling protocols

are described here (Figure 1B.9). Twenty-four circular surveys measuring 6.7 m (22 fi) in diameter

and four 100 m (328 ft) transect lines were sampled. At one platform (WC172), 200 m (656 ft)

transect lines were surveyed. Divers collected discrete samples of moribund fish in 25 m (82 ft)

increments along the transect line. Sampling width was either 1 or 2 m (3 or 6 ft) on either side of

the line depending on visibility. Sampling frames constructed of PVC pipe were placed beneath the

platform. Although frame dimensions varied due to obstructions encountered on the sea floor, the

total area sampled generally covered 20-30% of the footprint area beneath the platform. Extremely

small fish such as blenniies which live inside dead barnacles encrusting the structural members of

the platform were not targeted for collection. Generally, fish smaller than 8 mm total length were not

sampled. Due to time constraints and safety considerations all targeted samples were not always

collected.

Fish mortality was estimated by multiplying fish density (number of fish in sample divided by area

sampled) by total area for each region of interest (e.g. 0-25 m radius around the platform, 25-50 m,
55

50-75 m, etc. for transect line analysis). Similar procedures were applied to data collected from

circular surveys and sampling frames. The total estimated mortality at a study site was calculated by

adding the estimated fish mortalities at the surface, beneath the platform and in open water around

the platform to a maximum distance of 100 m. The transect and circular survey techniques served

as duplicate estimators for mortality in the open water area.

Population size was estimated for various species when pre-detonation fish tag and release efforts

were successful and sufficient numbers of tagged fish were recovered dead after blasting. Estimates

were calculated for individual species using direct proportions of tagged to untagged fish.

RESULTS

From 1993-1998 an assessment of fisheries impacts due to underwater explosives was conducted

at 9 platform removals which occurred during the months of May, June, July, August and September.

Study sites spanned the Louisiana coast from the western border to the Mississippi delta. Water

depths ranged from 14-36 m (45-118 ft). All platforms had 4 pilings except for one 24 pile structure.

The weight of explosives used per site was 160-640 lb. Structures varied in age from 12-39 years.

Total mortality estimates were calculated for 8 of the 9 platform removals studied. At the deepest

platform sea floor sampling by divers did not begin until 50 hours after the first of two detonation

sequences because the platform owner would not allow sampling until the structure had been toppled

in place and the salvage barge departed the site. Due to a combination of this and other factors

including zero visibility on the sea floor, strong currents, rough seas, and extremely large amount

of debris around the platform which resulted in entanglement of divers, insufficient data were

collected from the sea floor to provide estimates of fish mortality although surface mortalities were

collected using standard protocols.

Total estimated mortality ranged from less than 2,000 to 6,000 fish at individual platforms (Table

1 B.4). These figures appear small when compared with estimates from other sources of fish mortality

such as trawl bycatch. Very small fish less than about 8 cm are not routinely collected by divers.

Blennies account for most of these mortalities. However, during removal of the platform in West

Cameron Area Block 181, an abundance of small, dead fish other than blennies were encountered.

These carcasses were collected from one of the sampling frames placed beneath the platform. A

mortality estimate was calculated assuming uniform density of these fish in the footprint area of the

structure. Results indicated an estimated 6,400 mortalities of small fish, primarily vermilion snapper

(6100 mortalities), measuring less than 8 cm. Note that this figure does not include any estimate for

the area outside of the platform footprint.

Fish species with the highest estimated mortality included Atlantic spadefish, red snapper, blue

runner, and sheepshead. Estimated mortality at seven study sites ranged from 500-2,500 for

spadefish, 0-1,300 for red snapper, 0-1,500 for blue runner, and 100-1,100 for sheepshead.

Combining the results from these eight platforms yielded a total estimated kill of 10,170 spadefish,

4,387 red snapper, 4,200 blue runner, and 3,514 sheepshead. These four species accounted for

approximately 89% of the combined estimated fish mortality at these eight study sites.
56

Table 1B.4. Estimated fish mortality.

* Under platform

Prior to the detonation of explosives, a fish tag and release study was conducted. Although all

captured species were tagged and released, red snapper was by far the most numerous. Typical

recovery rates for tag-release studies of fish are about 5%. The percentage of tagged red snapper that

were recovered after detonations was 19%, 20%, 41%, 48%, 60%, and 64% at our successful study

sites (Table 1B.5). Too few red snapper were tagged at the other three sites to estimate population

size. High recovery rates indicated a large impact of underwater explosives on red snapper at

platform removals.

Data from the red snapper tag-release study conducted at WC 181 during summer 1997 were

especially interesting. Field work was interrupted for a week due to bad weather. Three estimates of

the pre-detonation population size of red snapper were calculated using data for fish tagged during

the first cruise, the second cruise, and both cruises combined. Results were similar(1,142; 936; and

1,048, respectively) indicating consistency between the two cruises. It is interesting to note that postdetonation recovery rate of tags was about 5% higher for the second cruise than for the first cruise.A

summary of all red snapper population and mortality, estimates to date is shown in Table 1 B .6.

Population estimates ranged from about 500-1,900 for those platforms where sufficient numbers of

fish were tagged. The percent of the population which was killed by blasting activity was calculated

by dividing estimated red snapper mortality by estimated population size. Results ranged from

57-90%. Actual mortality is probably higher due to artifacts inherent in tag-recapture studies.

Many factors affect fish mortality which occurs during the explosive removal of offshore structures.

The list may include but is not limited to such things as water depth, water temperature, salinity,

oxygen concentration, season, structure size and age, number of nearby structures, amount of

explosives used, placement and configuration of explosives, and sediment characteristics.

Depth

ft Size Age LBS Expi Depth (ft) BML

Es t.

F is h Kill

45 24pile 39 640 20-30 1500-1900+

48 4 pile 23 300 20 2000-2300

48 4 pile 19 210 16-20 2600-2900

55 4 pile 12 350 15 2200-4700

58 4 pile 33 160 20 4700-6000+ (6400 <8cm)* 82 4 pile 16 380 20 4300-5000

92 4 pile 17 350 13-25 3000

105 4 pile 37 250 20 1600-1900
57

Table lB .6. Red snapper population and mortality estimates.

Site % tag

recov.

Pop. est. Mortality Water

est. m 0 rtality depth (ft)

WD 30 45

WC 172 64 700 500 73 48

WC 173 19 1100 700 66 48

SS 158 0 300 55

WC 181 20 1000 900 90 58

SM123 41 1900 1200 61 82

ST 146 48 500 300 57 92

SS 209 60 600 400 71 105

Table 1B.5. Red snapper tag-recovery study.

Site

# # dead

tagged with tags Water

recovery depth (ft)

WD 30 0 0 0 45

WC 172 132 84 64 48

WC 173 172 32 19 48

SS 158 4 0 0 55

WC 181 298 60 20 58

SMI 23 44 18 41 82

ST 146 117 56 48 92

SS 209 58 35 60 105
58

Recent attention to the biological impacts of explosive platform salvage has resulted in discussion

of potential methods for mitigation. None has received overwhelming support. Topics include

attracting or repelling fish out of the impact zone, using bubble curtains or mats to dampen the effect

of the blast, and developing special shaped charges that can dramatically reduce charge weight and

subsequent blast over-pressure. Although additional research is required, recent developments in

configured explosives may prove very beneficial to the fish populations and other marine life which

occur at offshore oil and gas structures.

In conclusion, impacts of underwater explosives on fish appears small in terms of total numbers

when compared to other sources of mortality such as trawl bycatch. Standard deviation of mortality

estimates is a bit high probably due to small sample size as well as natural variability between fish

populations present at platforms Platforms in deeper water are generally believed to have larger red

snapper populations than shallow water structures.

REFERENCES

Dugas, R., V. Guillory and M. Fischer. 1979. Oil rigs and offshore sport fishing in Louisiana,

Fisheries 4(6):2-10.

Gitschlag, G.R. and B.A. Herczeg. 1994. Sea turtle observations at explosive removals of energy

structures. Marine Fisheries Review 56(2): 1-8.

Hastings, R.W., L.H. Ogren, and M.T. Mabry. 1976. Observations on the fish fauna associated with

offshore platforms in the Northeastern Gulf of Mexico. Fisheries Bulletin 74(2):387-402.

Lewbel, G.S., R.L. Howard and B.J. Gallaway. 1987. Zonation of dominant fouling organisms on

Northern Gulf of Mexico petroleum platforms. Marine Environmental Research. 21:199-224.

National Research Council. 1996. An Assessment of techniques for removing offshore structures.

National Academy Press, Washington D.C. 76 pp.

Scarborough-Bull, A. 1989. Some comparisons between communitiesbeneath petroleum platforms

off California and in the Gulf of Mexico. Fourth International Conference on Artificial Habitats

for Fisheries, Rigs-to-Reefs Special Session, pp. 47-50.

Sonnier, F., J. Teerling and H.D. Hoese. 1976. Observations on the offshore reef and platform

fish fauna of Louisiana. Copeia 1:105-111.

Stanley, D.R. and C.A. Wilson, 1990. A fishery-dependent based study of fish species composition

and associated catch rates around oil and gas structures off Louisiana. Fisheries Bulletin

88:719-730.
59

Gregg Gitschlag has worked for NOAA's Southeast Fisheries Center, Galveston Laboratory for the

past 20 years as an oceanographer and fishery biologist. His research interests include sea turtle

behavior and migration as well as recreational and commercial impacts on red snapper. Mr.

Gitschlag completed his B.S. in zoology at the University of Michigan and his M.S. in biological

oceanography at Florida State University.

PRELIMINARY SURVEYS OF SESSILE INVERTEBRATE COMMUNITY

ON A PARTIALLY REMOVED PLATFORM REEF OFF

SOUTH PADRE ISLAND, TEXAS

Mr. Terry B. Riggs

Dr. Quenton R. Dokken

Mr. Carl R. Beaver

Center for Coastal Studies

Texas A&M University-Corpus Christi

ABSTRACT

In 1997, Seagull Energy, Inc. petroleum production platform NPI 72 A was donated to the Texas

Parks and Wildlife Artificial Reef Program. In June 1997 a preliminary survey was conducted by

TAMU-CC-CCS personnel to obtain baseline data of the fouling community associated with the

platform prior to being partially removed. A post-cut survey (i.e. partial removal) was conducted during August 1998. Photographic analysis was used to determine vertical biologicalzonation, diversity,

dominance, evenness and area coverage. Rugosity measurements were taken to indicate of fouling

density. Data was compared to NPI 59 A, a standing petroleum platform, approximately 17 km north

which is still in production and two bluewater production platforms EB 165 A and HI 389 A.

INTRODUCTION

Researchers have long discussed the importance of artificial hard substratesto attract targeted sport

and commercial finfish species; hence the development of artificial reefs became an important aspect

for the recruitment and sustainability of finfish populations. Fish species such as the gray triggerfish,

Balistes capriscus, rock hind, Epinephelus adscensionis, and creole fish, Paranthiasfurcfer utilize

ciyptic macroinvertebrates as a food source (Beaver et al. 1997; Nelson and Bortone 1996).

Common herbivores such as sergeant major, Abudefdufsaxitilis, and several species of the genus

Pomatricentrus also utilize cryptic species as incidental food sources (Edwards 1992), making

cryptic invertebrate species an important nutrient resource.

Artificial reefs provide a 'reef of opportunity" for organisms that settle on hard bottom substrates

which are limited in the deeper waters of the northwestern Gulf of Mexico. Cyclic abiotic factors,

such as seasonality, light intensity, temperature and water depth influence the settling process of
60

larval and algal species. Many species settle within specific biological and photic zones within the

water column, while others have adapted to survive in all zones. Most marine organisms disperse

during a planktonic larval stage (Gallaway and Lewbel 1982; Beaver et al. 1997).

The development of a productive artificial reef is affected by the degree at which these organisms

can settle and survive, and the fish community is affected by the fouling community (Rooker et al.

1997; Beaver et a!, 1997). The purpose of this study was to provide information regarding the sessile

invertebrates (i.e. fouling community) of a South Texas nearshore platform reef.

STUDY SITES

This study was performed on the coastal petroleum production platform, Seagull Energy Inc. North

Padre Island (NPI) 72 A (26 52' 20.9" N x 096 46' 19.3" W), South Padre Island, Texas, which had

recently been donated to Texas Parks and Wildlife Department Artificial Reef Pro gram (TPWDARP)

for partial removal. During June 1997 a pre-cut survey was conducted to gather baseline data and

to characterize the fouling community and fish populations. North Padre Island 72 A was

mechanically severed at a depth of 33.5 m (110 ft). Data collected during June 1997 (pre-cut) and

August 1998 (post-cut) was compared to a standing platform, NPI 59A, located 18.5 km northeast

of NPI 72 A. The data was also compared to existing and previous studies performed on standing

platforms; High Island 389 A (27 54 30"N x 093 35t 06"W) and East Breaks 165 A (27 49"N x 094

19' W) located in blue water biological zones of the continental shelf in the northwestern Gulf of

Mexico.

North Padre Island 59 A is a petroleum production platform that is still in production. NPI 72 A and

NPI 59 A platforms are three pile (i.e. leg) platforms situated in 72 m of water, located in the North

Padre Island mineral lease block approximately 103.9 km and 89.2 km (respectively) east of Port

Mansfield, Willacy County, Texas. Mobile Exploration and Production United States (MEPUS)

High Island (HI) 389 A is located approximately 3.07 km east of the Flower GardenBanks National

Marine Sanctuary (FGBNMS) east bank. British Petroleum Exploration (BPX), East Breaks (EB)

165 A is located 157.4 km southeast of Galveston Island.

METHOD AND MATERIALS

Fouling community sampling was conducted using a modified photographic transect technique

(Ohlhorst etal. 1992). This technique produces a 35 mm color transparency of 0.50 m2 of substrate

using a Nikonos V camera, 28 mm lens, two SB 102 strobes and a photo framer with a Aqua Lung

D-Timer attached to record depth (Dokken etal. 1994). All photographs and samples were collected

utilizing SCUBA technology.

Vertical transects extended from a depth of 33.52 m to a depth of 53.34 m. Photographs were taken

at 1.52 m (5 fi) intervals on each of three piles and each transect contained 14 transparencies.

Transparencies were projected at a 1:1 ratio onto a screen with 100 randomly located points and

quantified using the planar point intercept method as per Ohlhorst et al. (1992). Organisms were

identified to lowest possible taxon and quantified.
61

When necessary, the images were magnified to facilitate species identification. A total of 144

transparencies were analyzed, producing a total of 14,400 data points. A checklistwas compiled, and

relative frequency was determined by dividing the total number of points from a given species by

the total number of points in the transect. Shannon Diversity Index (H') was utilized to assess species

diversity for each zone and values were calculated from the formula:

H' Piiog Pj

where p1 equals the decimal fraction of total individuals of the th species. Simpsons Dominance (Dii)

was calculated with the formula:

Dn 1-Epi2

Where pi2 equals the proportion of individuals found in the ith species and n equals the number of

individuals of a species.

Evenness (J') indices was calculated as:

J'H'/lnS

where S equals the total number of species.

A one-way analysis of variance (ANOVA) was used to determine significant differences in fouling

community diversity within population zones of the transects (CL= 0.05). Tukey's HSD was employed

to identify significantly different means.

Rugosity measurements were recorded for each 3.04 m (10 ft.) depth from 45.72 m (150 ft.) to the

top of the remaining section of piles (35 m). Rugosity (amount of surface relief formed by the fouling

community) is defined with the formula:

3 (X+1)- 1

RESULTS

Thirty-seven fouling species were identified and enumerated on NPI 72A during the pre-cut survey

(Riggs et al. 1998). A total of 36 species were identified and enumerated from NPI 72 A during the

post-cut survey. Analysis of NPI 59 A identified a total of 36 species. Forty-eight species were

identified from all platform reefs analyzed (Table 1 B .7). Two deep zones were delineated during the

pre-cut analysis at depths of 24.6 m and 42.8m (Table 1B.8). During the post-cut analysis, only a

single zone was present beginning at the cut area (30 m) and ending with the deepest depth used for

the analysis of53 .3 m (p = .326). Hydroids and sponges constituted the majority of organisms during

the pre-cut survey, covering 25% and 40%, respectively (Figure 1B.10). Post-cut analysis has determined an unidentified Chiorophytic algal species, perhaps of the genera Enteromorpha,dominatuug

the structure (44.4%), followed by sponge (21%). North Padre Island 59 A also displayed a high

percent algal coverage (35%) and reduced sponge coverage (23%) (Figure 1 B. 10).
62

Table 1B.7. Fouling species identified from photographic transects on NPI 72 A, NPI 59 A, EB

165 A, and HI 389 A.

Chiorophyta

Ulvaceae

Enteromorpha sp.

Cladophoraceae

Cladophora sp.

Chaetomorpha sp.

Hydroida

Sertularidae

Sertularia dalasi

Sertularia inflata

Sertularia turbinate

Plumularidae

Aglaophenia

cristfrons

Aglaophenia rigida

Campanularidae

Obelia dichotomy

Obelia hyalina

Thoracica

Balanidae

Balanus eburneus

Balanus sp.

Megabalanus

antillensis

Echinoidea

Arbaciidae

Arbacia punctulat

Diadematidae

Diadema antillarum

Octocoralia

Alcyonacia

Carjoa riisei

Telesto antillensis

Rhodophyta

Bangiaceae

Bangia sp

Ascidiacea

Unidentified sp.

Bryozoa

Membraniporidae

Membranipora sp.

Bicellariellidae

Bugula turrita

Bugula neritina

Schizoporelidae

Schizoporella sp.

Bivalvia

Isognomonidae

Iso gnomon bicolor

Arcidae

Arca zebra

Barbatia candida

Spondylidae

Spondylus americanus

Pteriidae

Pteria colymbus

Decapoda

Majidae

Stenorhynchus

Seticornis

Annelida

Amphinomidae

Hermodice

carunculata

Serpulidae

Spiro branchus

giganteus

Porifera

Dysideidae

Aplysilla sp.

Clathrinidae

Clathrina coriacea

Stellettidae

Stelletta sp.

Geodiidae

Geodia gibberosa

Suberitidae

Suberites sp.

Halichondridae

Halichondria sp.

Desmacellidae

Neofibularia

nolitangere

Myxillidae

Tedania ignis

Phorbasidae

Phorbas amaranthus

Clathriidae

Clathria schinata

Rhaphidoiphus

schoenus

Haliclonidae

Haliclona molitba

Callyspongiidae

Callyspongia sp.

Thorectidae

Irciniafelix

Scieractinia

Rhizangiidae

Astrangia solitaria

Oculindae

Oculina dffuse

Dendrophylliidae

Tubastrea coccinea
63

Shannon Diversity Index for the pre-cut study calculated mean values of 1.6 at 35 m to 1.4 at 53.3

m. Post-cut analysis displayed a Shannon Diversity Index mean of 1.68 at 35 m and 1.65 at 53.3 m.

Mean values for Simpsons Dominance Index from the pre-cut survey ranged from 0.26 at 35m to

0.27 at 53.3 m. The post-cut survey analysis demonstrated a Simpson Dominance Index of 0.48 at

35 m to 0.19 at 53.3 m. Analysis of the pre-cut survey concluded a mean Sheldon Eveness value of

0.72 at 35 m and 0.67 at 53.3 m. While the post-cutmean ranged from 0.63 at 35 m to 0.69 at 53.3

m. Pre-cut rugosity measurements recorded from NPI 72 A ranged between 0.25 (33.5 m) to 0.09

(45.7 m), while post-cut measurements for the same depths ranged between 0.03 and 0.13,

respectively (Figure 1B.1 1).

DISCUSSION

Post-cut analysis has demonstrated the loss of one deep water biological zone from the reef and a

reduction of invertebrate fouling community area coverage within the top of the remaining platform

piles. An algal species not observed during the initial pre-cut survey dominated the platfonn to a

depth of 53 m in the post-cut survey. Species diversity and dominance slightly increased from the

pre-cut values for the shallower depths, but the eveness values dropped considerably. Diversity and

eveness values for the deeper area increased, although the dominance values decreased.

Previous(1994 and 1996) diversity data reported from EB 165 A for comparable depths reported a

diversity value of 0.879 (Dokken et al. 1996), lower than diversity values for NPI 72 A pre-cut and

post-cut values (1.95 and 1.68, respectively) and NPI 59 A (1.56). However the data is consistent

with current data acquired from EB 165 A for this analysis (0.85).

Table 1B.8. Vertical zones delineated during analysis of NPI 72 A, NPI 59 A, EB 165 A, and HI

389 A.

Platform Reef Zone 1

Vertical Zone (m)

Zone 2 Zone 3 Zone 4

NPJ 72 A pre-cut 1.03 -3.04 3.3 -24.3 24.6 -42.5 42.8 -53.2

NPI 72 A post-cut Cut off Cut off 30 - 53.2

NPI59A 1.0-2.8 3.0-21.5 21.5-41.6 41.8-53.2

EB 165 A 1.0-4.6 4.8-22.3 22.5 -35.8 36.1 -53.2

HI 389 A LU -4.8 5.0 -27.6 27.8-53.2
64

451

4o,

35

AEaQ

(%)

I

Taa-iomc Qu

Figure 1B.1O. Percent coverage of pre- and post-cut fouling constituents.

Adams (1995) identified 27 sponge species on HI 389 A with Tedania ignis and NeojIbularia nolitangere being dominant species. During pre-cut analysis on NPI 72 A, 1'. ignis was the dominant sponge found and composed 40% of the area coverage for this group of invertebrates, and reduced to 35 % area coverage during the post-cut analysis. High Island 389 A also displayed lower dominance values than NPI 72 A and NPI 59 A.

Precut rugosity analysis displayed relief patterns similar to those found on EB165 A reported by Dokken et al. (1996) and Dokken et al. (1994); as depth increased, rugosity decreased. Recent data obtained from EB 165 A did not exhibit any decrease or increase as depth increased and remained a constant 0.07 m for these depth ranges (Figure 1B.11). Rugosity of HI 389 A was considerably higher, ranging from 0.46 at 33 m to 0.33 at 47 m (Figure 1B.1 1). Rugosity analysis on NPI 59 A also displayed a slight decrease with depth (Figure 1B.11).

During the pre-cut survey of NPI 72 A, a nephloid layer was observed beginning at approximately 50.6 m, but was not observed at 60 m during the post-cut survey. The nephloid layer likely affected

colonization patterns and biomass within the deepest zone observed during the pre-cut analysis.

Funded by the Texas Parks and Wildlife Department Artificial Reef Program (TPWDARP) in cooperation with Texas A&M University-Corpus Christi - Center for Coastal Studies (TAMUCC- CCS), this study will continue and be expanded to include otherartificial reefs along the Texas coast.

72Ape.cit

Ia

o-.

72Apost-ai

LiSA

Ic C W D 0 C -- . I- o

- 0 NW

0

1165A

D389A
0.5

0.4-

0.3-

Rugosity (m)

0.2-

0.1 - 0

33.5 36.5 39.2 426 45.7

Depth (m)

Figure 1B.11. Comparison of rugosity measurements from 33.5-45.7 meters at each site.

REFERENCES

Adams, C.L. 1995. Species composition, abundance and depth zonation of sponges (Phylum

Porifera) on an outer continental shelf gas production platfonn, northwestern Gulf of Mexico.

Masters Thesis. Center for Coastal Studies, Texas A&M Univ.-Corpus Christi, Corpus Christi,

TX. 128 pp.

Beaver, C.R., Q.R. Dokken and T. Riggs. 1998. Utilization of fouling community elements by reef

fishes at a platform artificial reef in the northwestern Gulf of Mexico. Proceedings: Seventeenth

Annual Gulf of Mexico Information Transfer Meeting. Minerals Mgmt. Service. New Orleans,

LA.

Dokken, Q. R., C.R. Beaver, S.Cox, C.Adams, J. Rooker and J. Childs. 1996. Characterization of

biofouling communities on oil and gas production platforms: Impact of finfish assemblages.

Proceedings: Fifteenth Annual Gulf of Mexico Information Transfer Meeting. Minerals Mgmt.

Service. New Orleans, LA.

Dokken, Q.R., C.R. Beaver and S. Cox. 1994. Investigations of oil and gas platform jackets as

artificial reefs: Interim report, East Breaks 165. Center for Coastal Studies, Texas A&M-Corpus

Christi. Corpus Christi, TX.

65

E165A

72APost-cut

72APre-cut

059A

389A
66

Gallaway, B.J. and G.S. Lewbel. 1982. The ecology ofpetroleum platforms in the northwestern Gulf

of Mexico: a community profile. U.S. Fish Widi. Serv., Off.Bio. Serv., FWS/OBS-82/27. J3ur.

Land Mariag., Gulf of Mexico OCS Reg.Off., Open File Rep. 82-03. 92 pp.

Olhorst, S.L., W.D. Liddell, R.J. Taylor and J.M. Taylor. 1992. An evaluation of reef census

strategies: implications for monitoring programs. Pac. Sci. 46 (3) :380.

Riggs, T.E., C.R. Beaver, L.D. Vitale and Q.R. Dokken. 1998. Preliminary ecological survey,

Seagull Energy, Inc. platform NPI 72 A off southTexas coast. Center for Coastal Studies, Texas

A&M University-Corpus Christi. TAMU-CC-9803-CC5. 34 pp.

Rooker, J.R., Q.R.Dokken, C.V. Pattengill and G.J.Holt. 1997. Fish assemblages on natyral and

artificial reefs in the Flower Garden Banks National Marine Sanctuary, USA. Coral Reefs. 16: 83-92.

Terry Riggs is a graduate research assistant with the Center for Coastal Studies. Mr. Riggs is

interested in invertebrate community ecology and dynamics associated with artificial and natural reefs. He earned his B.S. from Texas A&M University, Corpus Christi.

Dr. Queriton Dokken is the Associate Director of the Center for Coastal Studies at Texas A&M

University, Corpus Christi. Dr. Dokken's interests are in artificial reef ecology and dynamics,

fisheries management, and ecosystem sustainability. He earned B.S. arid M.S. degrees in biology

from Corpus Christi State University and a Ph.D. in wildlife & fisheries sciences from Texas A&M

University.

Carl Beaver is a research assistant with the Center for Coastal Studies at Texas A&M University- Corpus Christi. Mr. Beaver's interests are in natural and artificial reefs. Mr. Beaver received his B. S.

degree from Corpus Christi State University and M.S. from Texas A&M University-Corpus Christi. Mr. Beaver is currently pursuing a doctorate in wildlife and fisheries science at Texas A&M

University Corpus Christi.
PRELIMINARY OBSERVATIONS OF FISH ASSEMBLAGES

ASSOCIATED WITH A PARTIALLY REMOVED

PLATFORM OFF THE TEXAS COAST

Ms. Lisa D. Vitale

Dr. Quenton R. Dokken

Center for Coastal Studies

Texas A&M University - Corpus Christi

INTRODUCTION

Oil platforms are unique reef ecosystems extending throughout the water column providing a large volume and surface area, dynamic water flow characteristics and a strong profile (Dillon and Falk

1981; Dokken 1997; Stanley and Wilson 1990). Often, in the northern Gulf of Mexico, areas where

oil platforms are located consist of a featureless seabed, and a reduced reef fish population (Meier

1989). Fish are attracted to oil platforms because these structures provide food, shelter from

predators and ocean currents, and a visual reference which aids in navigation for migrating fishes

(Bolmsack 1989; Duedall and Champ 1991; Meier 1989). Community characteristics of pelagic,

demersal and benthic fishes are affected by the size and shape of the structure (Stanley and Wilson

1990).

According to Scarborough-Bull and Kendall (1992) there are over 5,000 oil platforms in the Gulf

of Mexico and it has been estimated that they have increased the hard substrate in this area by as

much as 28%. In recent years, 110 obsolete oil platforms in the Gulf ofMexico have been converted

for use as artificial reefs (Reggio 1996).

Some scientists feel that a limiting factor to abundance formany fish species is the amount of hardbottom habitat available, and that the presence of oil platform structures allows for the fish pop- ulations to grow, therefore increasing the fishery potential (Scarborough-Bull and Kendall 1992). It is likely that offshore oil platforms influence fish populations, however, due to inadequate information, there is some question as to the efficacy of artificialreefs and whether they simply aggregate

fish populations or actually support increases ofbiomass (Polovina 1991; Scarborough-Bull and

Kendall 1994; and Bortone et al. 1997). The purpose of this study is to advance understanding of the

influence of platform reefs on finfish communities in the northwestern Gulf of Mexico.

STUDY SITE

The study was conducted on North Padre Island A72A (26° 52" 20.9'N x 96° 46" 1 9.2'W), a Seagull Energy Inc. petroleum production platform, located approximately 56.3 km northeast of Port Mansfield, Texas, in the Gulf of Mexico (Figure 18.12). Water depth at the artificial reef site is 73

meters. The total volume of the reef site is 10,337 m3 and the surface area is 16,576 m2. North

67
68

I

Rio Grande

Mexico

One inch Equels Approximately 52 Kilometers

U 5 10 20 O 40 E2 '

Port

Mansfield

Figure 1B.12. Location of study site in relation to Padre Island National Seashore, Port Mansfield, and the Rio Grand.
69

Padre Island A59A (26° 61" 27.9'N x 96° 45" 17.6'W) was the platform used as a point of comparison. This platform is located 1 72 km north-northeast from North Padre Island A72A.

METHODS AND MATERIALS

The pre-cut survey ofNPI A72A occurred on 10-11 June 1997 and the post-cut surveys ofNPI A72A

and NPI A59A (control) on 10-11 August 1998. NPI A72A was mechanically removed at 3 Om depth

on 1 August 1998 and the top portion of the structure was laid horizontally on the ocean floor.

Pelagic fish populations were surveyed using a modified version of the stationary visual census

method (Bohnsack and Barinerot 1986; Dokken et al. 1993). Two divers were positioned vertically

in the water column on each side of the structure, with enough separation so the field ofsurvey was

non-overlapping. Surveying began with divers facing the platform. Each diver rotated slowly, 3 60°,

identifying and counting all fish species observed within an imaginary cylinder with a 7m radius and depth. Each rotation was about one minute in duration. Only fish species observed within that time

period were recorded. Three rotations were made at each position before moving to another location

at that same depth or another depth. If schooling fish were present during a survey, they were

counted first to avoid counting the same individual more than once. Surveys began at a depth of 3 6m

and were taken at 6m intervals ending at a depth of 6m. At least 3 replicate surveys were performed

at each depth.

For surveying cryptic reef fish species (those closely associated with the platform structure), a onemeter line with weights attached at each end marked the area of the structure to be surveyed. The placement of the line was random. Divers were positioned on opposite sides of the leg. All cryptic

fish species within this one-meter transect around the circumference of the leg were identified and

counted. Three surveys were performed at 6m intervals at each depth between 3 6m and the surface.

RESULTS

NPI A72A Pre-Cut Assemblages

A total of 24 pelagic and reef fish species representing 2 orders, 12 families, and 18 genera were observed (Table 1B.9). The dominant families (i.e.numbers of individuals) were Carangidae (jacks), 8,318 (98.9%), Lutjanidae (snappers), 452 (4.9%), l3lenniidae (blennies), 151 (1.6%), and Pomacentrjdae (damselfishes), 91(0.9%).

Of the pelagic species, the most abundant (i.e. number of individuals) species was the lookdown,

Selene vomer, with 7,100 out of 8,323 individuals counted (=85.0%). Following the lookdown, the

relative abundance of other pelagic species were the horse-eye jack, Caranx latus, 741 (8.9%), the blue runner, Caranx crysos, 395 (4.7%), and the greater amberjack, Seriola dumerili, 67 (0.7%).

The most abundant of the reef fish were the gray snapper, Lutfanus griseus, 435 (50.0%), tesselated

blenny, Hypsoblennius invemar, 122(14.0%), sergeant major,Abudefdufsaxatiljs 91(10.5%), and

the spotfin hogfish, Bodianus puichellus, 48(5.6%).
70

Table 1B.9. Numbers of fish observed during surveys for the pre and post-cut of NPI A72A and NPI A59A (control).

Species NH A72A

Pre-Cut

NH A72A

Post-Cut

NPIA59A

Control

Family Carangidae

Alectis ciliaris 0 52 50

Caranxcrysos 395 235 960

Caranx hippos 14 16 13

Caranxlatus 741 3005 64

Elagatis bipinnulata 0 74 0

Serbia dumerili 64 52 29

Seriola rivoliana 4 2 0

Selenevomer 7100 0 1356

Family Kyphosidae

Kyphosus sectatrix 35 0 373

Family Rachycentridae

Rachycentron canadum 5 1 1 Family Lutjanidae

Lujanus campechanus 17 0 0

Lutjanusgriseus 435 234 367

Family Pomacentridae

Abudefdufsaxatjijs 91 9 2

Chromis mutilineata 0 0 25

Stegastesfuscus 0 0 1 Ste gastes partitus 0 0 7

Stegastespianfrons 0 0 2

Stegastes variabilis 0 0 6

Family Pomacanthidae

Holacanthus bermudensjs 0 0 1 Holacanthus ciliaris 0 0 1 Family Serranidae

Epinephelus adscensionis 9 1 14

Epinephelus nigritus 1 0 0

Paranthiasfurqfer 43 94 56

Family Cirrhitidae

Ainbiycirrhituspinos 1 0 0

Family Chaetondontidae

Chaetodon oceliatus 0 1 2

Family Scombridae

Sardasarda 0 800 221
71

NPI A72A Post-Cut Assemblages

A total of 21 pelagic and reef species representing 2 orders, 12 families, and 17 genera were

observed (Table 1 B.9). The dominant families (i.e. numbers ofindividuals) were Carangidae (jacks),

3,436 (71.5%), Scombridae (mackerel), 800 (17.0%), Lutjanidae (snappers), 243 (5.0%), and Ephippidae (spadefish), 117 (2.4%),

Of the pelagic species, the most abundant (i.e. number of individuals) species was the the horse-eye

jacks, Caranx latus, 3,005 (79.6%), the Atlantic bonito, Sardasarda, 800 (19.0%), the blue runner,

Carnax crysos, 235 (6.0%), and the rainbow runner, Elagatis bipinnulata, 74 (1.7%). Of the reef

fish, the gray snapper, Lutjanus griseus, 234(43.0%), theAtlantic spadefish, Chaetodipterusfaber, 117 (2 1.0%), the creole fish, Faranthiasfurcfer, 94 (17.0%), and the spotfin hogfish, Bodianus

puichellus, 83 (15.0%) were most abundant.

NPI A59A Control Assemblages

A total of 32 pelagic and reef species representing 2 orders, 14 families, and 25 genera were

observed (Table 1 B .9). The dominant families (i.e. numbers of individuals) were Carangidae (jacks),

Table 18.9. (continued)

Species NPI A72A

Pre-Cut

NP! A72A

Post-Cut

NPJA59A

Control

Family Labridae

Bodianuspuichellus 48 83 9

Bodianus rufus 1 3 5

Clepticusparrae 27 0 4

Family Blenniidae

Hypsoblennius invemar 122 0 151

Ophioblennius atlanticus 2 1 2

Farablennius marmoreus 27 1 67

Scartella cristata 0 0 6

Family Ephippidae

Chaetodipterusfaber 3 117 373

Family Sphyraenidae

Sphyraena barracuda 1 10 230

Family Balistidae

Balistes capriscus 6 3 3

Family Tetraodontidae

Canthigaster rostrata 0 0 2
72

2,472(59.0%), Kyphosidae (chub), 373 (8.9%), Lutjanidae (snapper), 367(8.7%), and Sphyraenidae

(barracuda), 230 (54%).

Of the pelagic species, the most abundant (i.e. number of individuals) species was the lookdown, Selene vomer, 1,356 (50.0%), the blue runner, Caranx crysos, 690 (36.0%), the Atlantic bonito,

Sarda sarda, 221 (8.2%), and the horse-eye jack, Caranx latus, 64 (2.4%). Of the reef fish species, the bermuda chub, Kyphosus sectatrix, 373 (25.0%), the gray snapper, Lutjanus griseus, 367

(24.5%), the great barracuda, Sphyraena barracuda, 230 (15.4%), and the tesselated blenny, Hypsoblennius invemar, 151(10.0%).

DISCUSSION

North Padre Island A72A supported a diverse fish assemblage composed of both pelagic and reef

species. Fish assemblages encountered on the pre- and post-cut survey of NPI A72A were similar

to what has been found on other offshore oil platforms in the Gulf of Mexico (Hastings etal. 1976; Sonnier et al. 1976; Gallaway and Lewbel 1982; Scarborough-Bull 1987; Dokken et al. 1993; Bortone et aL 1997; and Rooker et aL 1997). Of the 28 fish species observed on the pre and post-cut surveys, ten species were seasonal transients, the carangids, rachycentrids, scombrids, and

sphyraenids, while the others constituted residentspecies which consisted primarily of the lutjanids, ephippids, blenniids, and labrids.

Pre-Cut vs. Control

A total of seven pelagic species was found on the pre-cut survey representing 8,323 individuals, and eight pelagic species on the control with 2,694 individuals. Carangidae dominated pelagic surveys, 99.8% of the pre-cut survey with the lookdowns (S. vomer) and 99.5% without the lookdowns, and 91.8% of the control platform. The lookdowns on the pre-cut survey were present in high numbers, 7,100 out of 8,323 individuals counted. Substantial numbers of lookdowns were encountered on the control site survey (=50.0%) although not as extreme as on the pre-cut survey. As for the reef species, Lutj anidae dominated on the pre-cut survey (=5 1.9%) and Kyphosidae on the control survey

(=z25.0%).

Vertical stratification of pelagic fish on the pre-cut survey showed that at 12m depth the greatest species diversity, with six, occurred. The highest density occurred at 1 8m with 2,295 individuals

(Table 1 B. 10 ; Figure 1 B. 13). At the control site, the greatest diversity of pelagic species was seen

at 30m with the highest density at 36m with 1,220 individuals. On the control platform, 6m and 12m

accounted for one species each, however, on the pre-cut survey these depths had a diverse number

of species with five at 6m and six at 1 2m. As for the reef fish species, the vertical stratification on

the pre-cut survey showed that 1 2m exhibited the greatest diversity with 10 species (also the same depth for the plagic species), with

the highest density at 36m with 253 individuals (Table 1B.10; Figure 18.14). Reef fish species on the control platform exhibited the greatest diversity at 1 8m with 15 species and the highest density
73

Table 1B.10. Numbers of fish at each depth found on the pre- and post-cut survey of North Padre

Island A72A and North Padre Island A59A (control).

Total Numbers/Depth

6m 12m 18m 24m 30m 36m

PRE-CUT Pelagic:

Caranxcrysos 195 129 29 0 17 25

Caranxhzpos 2 4 0 0 2 6

Caranxlatiis 150 440 0 150 0 1 Rachycentron canadum 0 3 1 1 0 0

Selenevomer 394 474 2235 1572 1157 1268

Seriola dumerili 3 4 28 12 11 6

Seriola rivoliana 0 0 2 2 0 0

Reef:

Abudefdufsaxatiiis 14 9 2 66 0 0

Arnblycirrhituspinos 0 0 0 0 0 1 Balistes capriscus 0 0 3 3 0 0

Bodianus puicheilus 1 6 10 13 5 13

Bodianus rufus 0 1 0 0 0 0

Chaetodipterusfaber 1 0 0 1 0 1 Clepticus parrae 0 20 0 0 0 0

Epinephelus adscensionis 0 0 1 8 0 0

Epinephelus nigritus 0 0 0 0 0 1 Hypsoblennius invemar 77 38 0 0 4 3

Kyphosussectatrix 17 12 4 0 2 0

Lutjanuscampechanus 0 1 12 1 0 3

Luljanusgriseus 0 24 3 12 94 224

Ophioblennius atlanticus 0 0 1 0 0 1 Parablennius marmoreus 7 11 2 1 2 0

Paranthiasfurcifer 0 0 0 25 12 6

Sphyraena barracuda 0 1 0 0 0 0

POST-CUT Pelagic:

Alectis ciliaris 0 0 10 15 8 19

Caranxcrysos 32 0 53 104 25 21

Caranxhippos 0 4 0 12 0 0

Caranxlatus 90 258 1263 379 756 259

Elagatis bipinnulata 7 0 43 0 16 8

Rachycentron canadurn 0 0 0 1 0 0

Sardasarda 90 0 394 314 0 2

Seriolci dumerili 0 0 8 26 1 17

Seriola rivoliana 0 0 0 2 0 0

Reef:

Abudefdufsaxatilis 0 0 0 0 0 9

Balistes capriscus 0 0 0 1 0 2

Bodianus puichellus 0 0 0 2 2 79

Bodianus rufus 0 0 0 0 0 75
74

Table 18.10. (continued)

Total Numbers/Depth

6m 12m 18m 24m 30m 36m

Chaetodzpterusfaber 0 27 63 26 0 1 Chaetodon ocellatus 0 0 0 0 0 1 Epinephelus adseensionis 0 0 0 0 0 1 Lutjanusgriseus 0 0 11 112 2 118

Ophioblennius atlanticus 0 0 0 0 0 1 Parablennius marmoreus 0 0 0 0 0

Paranthiasfurcfer 0 0 0 73 0 21

Sphyraena barracuda 3 5 0 2 0 0

CONTROL Pelagic:

Alectis ciliaris 0 0 41 0 4 5

Caranx crysos 0 8 214 141 357 240

Caranx hippos 0 0 0 J 3 0 0

Caranx latus 0 0 62 0 2 0

Rachycentron canadum 0 0 0 0 1 0

Sarda sarda 76 0 0 0 145 0

Selenevomer 0 0 100 0 308 948

Seriola dumerili 0 0 1 1 0 27

Reef:

Abudefdufsaxatilis 14 2 5 0 0 0

Balistes capriscus 1 0 0 0 2 0

Bodianus puichellus 0 0 2 0 5 1 Bodianus rufus 2 0 3 0 0 0

Canthigasterrostrata 0 1 1 0 0 0

Chaetodipterusfaber 0 22 115 0 1 0

Chaetodon ocellatus 0 0 2 0 0 0

Chromis multilineata 12 13 0 0 0 0

Clepticusparrae 0 1 0 0 l 3

Epinephelus adscensionis 1 6 2 0 2 2

Holacanihus bermudensis 0 0 0 0 0 1 Holacanthus ciliaris 0 0 0 0 1 0

Hypsoblennius invemar 69 57 22 2 0 1 Kyphosussectatrix 79 230 13 0 51 0 Lutjanusgriseus 101 26 51 24 149 16

Ophioblennius atlanticus 1 0 0 1 0 0

Parablennius marmoreus 16 13 28 7 1 2

Paranthiasfurcfer 7 14 27 0 7 3

Scartella cristata 0 0 0 6 0 0

Sphyraena barracuda 172 35 15 7 0 1 Stegastesfuscus 0 1 0 0 0 0

Stegastes part it us 0 0 3 0 2 2

Stegastes plan frons 0 2 0 0 0 0

Stegastes variabilis 3 3 1 0 0 0
75

Figure 1 B.13. Vertical stratification (total numbers at each depth) of pelagic fish species (*PreCut:

with lookdowns/without lookdowns).

at 6m with 479 individuals. The control platform had the greatest numbers of species and individuals

above 1 8m. The control platform had greater diversity with 24 species, whereas, the pre-cut platform

had 17 species.

Post-Cut vs. Control

A total of nine pelagic species were observed on the post-cut survey representing 4,237 individuals,

and eight pelagic species on the control with 2,694 individuals. Cararigidae dominated pelagic

surveys, 79.6% of the post-cut survey and 91.8% of the control platform. As for the reef species, a

total of 12 species and 564 individuals was found on the post-cut platform with Lutjanidae

representing the dominant family (43.O%), and 24 species representing 1,491 individuals with

Kyphosidae dominating on the control survey (25.0%).

Vertical stratification of pelagic fish on the post-cut survey showed that 24m exhibited the greatest

diversity with eight species and the highest density at 18m with 1,771 individuals (Table 1B.10;

Figure 1 B. 12). As for the control platform, the greatest diversity was at 3 Om with the highest density

Control Post-Cut

76 219

8 262

418 1771

155 853

817 806

1220 326

PreCut*

6m 744/350

12m 1054/580

18m 2295/60

24m 1737/165

30m 1187/30

36m 1300/32
76

Figure 1B.14. Vertical stratification (total numbers at each depth) of reef fish species.

at 36m with 1,220 individuals. The highest numbers of pelagic fish were observed swimming above

the structure between 1 8m-24m.

As for the reef fish species, the vertical stratification on the post-cut survey showed that 36m

exhibited the greatest diversity with 11 species and the highest density at 3 6m with 237 individuals

(Table 18.10; Figure 1B.13). Reef fish species on the control platform exhibited the greatest

diversity at 1 8m with 15 species and the highest density at 6m with 479 individuals. The control

platform had a more diverse reef fish community with 24 species, whereas, the post-cut platform had

12 species. The reduction of reef fish species seen on the post-cut survey can be attributed to the lack

of structure above 3 Om. There appears to have been a downward shift in reef fish with the removal

of the structure. The majority of reef species were seen at 24m with 216 individuals and 3 6m with

237 individuals with 30m (4 individuals) appearing to be a transition zone.

Pre-Cut vs. Post-Cut

The number of pelagic species remained similar, although there were no lookdowns (S. vomer)

encountered on the post-cut structure. Being that pelagic fishes are transient species, their diversities
77

and densities will likely change throughout the year. Horse-eye jacks (C. latus) were found in high

numbers on both the pre-cut survey (=8.9%) and post-cut survey (=70.9%).

With the removal of the structure above 30m, changes occurred in the reef fish community between

the pre-cut survey and post-cut survey (Figure 1 B.13). Densities and diversities were reduced on the

post-cut survey. Very few reef species were seen above 18m, the majority of these were the great

barracuda (S. barracuda) and the Atlantic spadefish (C. faber). A downward shift in depth was

observed, the majority occuring at 24m with six species and 216 individuals and at 36m with 11

species and 237 individuals. The greatest difference could be seen with the spotfin hogfish

(B. puichellus) with only 13 individuals enumerated on the pre-cut survey and 79 on the post-cut

survey. Gray snapper (L. griseus) was found at the greatest densities at 3Gm on the pre-cut survey;

however, no gray snapper were found at 3Gm on the post-cut, although 112 individuals were counted

at 24m. Reef fish were observed swimming above the structure at 24mjust as the pelagic fishes were

observed.

CONCLUSION

The NPI A72A platform, before and after partial mechanical removal, supported a diverse population

of both pelagic and reef fish species. Changes in zonation occurred. Results from this study may

provide a useful basis from which to evaluate other oil platform and artificial reef research. Longterm monitoring of the NPJ A72A artificial reef and NPI A59A (control) over a range of variables

is necessary in order to conclusively describe the dynamics of this reef ecosystem. This is a work in

progress and more surveys are planned for NPI A72A and NPI A59A (control).

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79

Stanley, D. R. and C. A. Wilson. 1990. A fishery-dependent based study of fish species composition

and associated catch rates around oil and gas structures off Louisiana. Fisheries Bulletin, U. S.

88: 7 19-730.
Comparison of 1-Hour and 8-Hour Ozone

Impact Calculations for Gulf of Mexico OCS

Activities

Intercomparison of Air Pollutant Dispersion

Models

Dispersion Meteorology Over The Breton

National Wildlife Area (BNWA)

The Breton Air Quality Study/Breton

Aerometric Monitoring Program

Boundary Layer Study in the Western and

Central Gulf of Mexico

SESSION IC

ATMOSPHERIC SCIENCES SESSION

Co-Chairs: Dr. Alexis Lugo-Fernndez and Ms. Terry Scholten

Date: December 8, 1998

Presentation Author/Affiliation

Project Status Report: Emissions Inventories Mr.

of OCS Production and Development

Activities in the Gulf of Mexico

Mr. Dirk C. Herk.hof

Mr. Charles F. Marshall

U.S. Department of the Interior

Minerals Management Service

Herndon, VA

Dr. Mark E. Fernau

Mr. Joseph C. Chang

Mr. Joseph S. Scire

Mr. David G. Strimaitis

Earth Tech, Inc.

Concord, MA

Lyle R. Chinkin

Sonoma Technology, Inc.

Dr. S.A. Hsu

Louisiana State University

Dr. Stephen D Ziman

Chevron Research and Technology Company

Richmond, California

Dr. Paul T. Roberts

Mr. Timothy S. Dye

Sonoma Technology, Inc.

Dr. Steven R. Hanna

Consulting Meteorologist

81
COMPARISON OF 1-HOUR AND 8-HOUR OZONE IMPACT CALCULATIONS

FOR GULF OF MEXICO OCS ACTIVITIES

Mr. Dirk C. Herkhof

Mr. Charles F. Marshall

U.S. Department of the Interior

Minerals Management Service

Herndon, VA

EXECUTIVE SUMMARY

Modeling output from the Gulf of Mexico Air Quality Study (GMAQS) was used to evaluate OCS

impacts relative to the new 8-hour average ozone standard. Model results were available for the 17-

20 August and the 6-11 September 1993 ozone episodes using year 1993 emissions data. In the

Southeast Texas model domain, the highest OCS contribution to the daily maximum 8-hour average

ozone value at those locations on shore where the predicted values exceeded 85 ppb was less than

1% of the total concentration in the August episode, and about 6% of the total concentration in the

September episode. Impacts over the offshore waters in the Gulf of Mexico were slightly larger. In

the Louisiana model domain, the highest OCS contribution to the daily maximum 8-hour average

ozone value at those locations on shore where the predicted values exceeded 85 ppb was about 5%

of the total concentration in both the August and September episodes.

This study showed that the effects of OCS emissions relative to the new 8-hour standard are larger

than those relative to the former 1-hour standard. The area of impact on any particular day tended

to be rather limited. An analysis of the wind field indicated that recirculation and offshore pooling

of ozone tended to play a major role in generating OCS impacts onshore. It was concluded that there

is clearly a need to conduct additional work to evaluate OCS impacts relative to the new 8-hour

standard.

INTRODUCTION

On 18 July 1997 the Environmental Protection Agency (EPA) promulgated anew ambient air quality

standard for ozone (Federal Register 1997). The existing ambient standard was 0.12 parts per

million (ppm) for the maximum 1-hour average. The standard allows less than one day per year,

based on three years of continuous data, when the maximum 1-hour ozone concentrationmay exceed

0.12 ppm. The revised primary standard is based on an 8-hour average ozone value of 0.08 ppm. The

annual fourth-highest daily 8-hour average ozone concentration averaged over three years cannot

exceed 0.08 ppm. In the year 2000, the States are required to determine which areas do not meet the

new 8-hour standard based on three years of data (1997-1999). Current monitoring data indicate that

a number of areas that presently meet the 1-hour standard will not meet the new 8-hour standard.

83

The Minerals Management Service (MMS) conducted a study, the Gulf of Mexico Air Quality

StudyGMAQS), to determine the impacts of OCS emissions in the Gulf of Mexico on adjacent
84

onshore areas in Texas and Louisiana relative to the 1 -hour ozone standard (MMS 1995). It was

determined from this study that the effect ofOCS emissions on ozone was small. With the upcoming

implementation of the 8-hour ozone standard, it will be important to know what the OCS impacts

are likely to be, relative to this new standard. The objective of this paper is not to present with any

certainty the expected magnitude of these impacts. Rather, it is to provide a qualitative measure of

how the OCS impacts may be affected by the longer averaging time and lower threshold associated

with the new standard. It also describes the atmospheric processes that may be important in

characterizing the 8-hour average impacts.

SUMMARY OF OCS CONTRIBUTIONS TO 1-HOUR

AVERAGE OZONE CONCENTRATIONS

The GMAQS applied the UAM-V model for two multi-day ozone episodes, 17-20 August and 6-11

September 1993. OCS impacts were determined by running two emission scenarios, one that included all onshore emissions and another that had OCS-petroleum-related emissions subtracted out.

The overall model domain extended from South Texas to the Florida Panhandle and utilized 72 by

62 grid cells with 16 kin grid spacing. A more refined sub-domain was used for Southeast Texas that

consisted of 62 by 55 grid points with 4km grid spacing. The maximum daily 1-hour average ozone

concentration was determined for each grid cell. The OCS contributions were determined for each

grid point by subtracting one model run from the other. Table 1 C. 1 presents the GMAQS for two

subareas, Southeast Texas and Louisiana (with the latter also including the Mississippi coastal area).

Southeast Texas

In the 17-20 August episode, the highest simulated 1-hour average ozone concentrations occurred

over the Houston metropolitan area to the northwest of Galveston Bay. The highest calculated daily

maximum ozone values were well above 125 ppb on all episode days and reached 223 ppb on 19

August. The highest OCS contribution to the daily maximum value was 7.5 ppb at a location about

Table 1 C. 1. Maximum Predicted OCS Contributions to the Daily Maximum 1-Hour Average

Ozone Concentration, 1993 Emissions.

'NA indicated not applicable. No value exceeds 125 ppb.

Southeast Texas

Highest OCS Contribution, ppb, at Locations

Where 0. Concentrations Exceed 125 ppb

Over Water Over Land

August Episode NA' 0.4 (<1%)

September Episode 6.6 (4%) 3.2 (2%)

Louisiana

August Episode NA' 0.5 (<1%)

September Episode 2.9 (2%) 2.1 (1.5%)
85

100 km from shore and where the total ozone concentration was about 50 ppb. At those grid points

where the daily maximum 1 -hour ozone value exceeded 125 ppb, the highest OCS contribution was

only 0.4 ppb, which is less than 0.5% of the total concentration at that point. This occurred over land;

there were no points over water where the ozone concentration exceeded 125 ppb.

In the 6-11 September episode, the highest 1-hour average ozone concentrations occurred over

Galveston Bay and adjacent coastal areas. High ozone concentrations were found near the coast and

extending some distance offshore. The highest simulated daily maximum 1-hour ozone values

exceeded 125 ppb on all episode day, except one, and reached 234 ppb on 9 September. The highest

OCS contribution to the daily maximum value was 15 ppb at a location well offshore and where the

total concentration was about 80 ppb. At those grid points where the daily maximum value exceeded

125 ppb, the highest OCS contribution was 6.6 ppb, which is about 4% of the total concentration.

If one considers grid points on land only, the highest OCS contribution was 3.2 ppb, or about 2% of

the total concentration.

Louisiana

In the 17-20 August episode, the highest simulated 1 -hour average ozone concentrations occurred

over the Baton Rouge area. The highest daily maximum 1-hour ozone values exceeded 125 ppb on

the last 2 days of the episode and reached 140 ppb on 20 August. The highest OCS contribution to

the daily maximum 1-hour ozone concentration was 30 ppb at a location about 80 km offshore

central Louisiana. The total ozone concentration at that point was about 70 ppb. At those points

where the total concentration exceeded 125 ppb, the highest OCS contribution was 0.5 ppb, which

was less than 0.5% of the total concentration. This occurred in the Baton Rouge area.

In the 6-11 September episode, the highest simulated ozone concentrations generally occurred over

southwestern Louisiana area. The highest daily maximum 1-hour ozone values exceeded 125 ppb

on only 1 day, 10 September, with a highest value of 181 ppb. The highest OCS contribution to the

daily maximum 1-hour ozone concentration was 22 ppb at a location well offshore southwestern

Louisiana. At those grid points where the daily maximum value exceeded 125 ppb, the highest OCS

contribution was 2.9 ppb, which is about 2% of the total concentration. This value also occurred just

offshore southwestern Louisiana. If one considers grid points on land only, the highest OCS

contribution was 2.1 ppb, or about 1.5% of the total concentration.

SUMMARY OF OCS CONTRIBUTIONS TO THE 8-HOUR

AVERAGE OZONE CONCENTRATIONS

Running 8-hour average ozone concentrations were calculated from the model output for the two

episodes for each grid point in the Southeast Texas and Louisiana model subdomains. The daily

maximum 8-hour average ozone concentration was determined for each grid point. The OCS

contributions to the daily maximum value were calculated by subtracting the model output without

OCS petroleum-related emissions from the model output with the OCS petroleum-related emissions.

Highest OCS contributions were determined for each day for those grid points where the daily

maximum ozone concentration exceeded 85 ppb. This provides a measure of the relative importance
86

Table 1C.2. Maximum Predicted OCS Contributions to the Daily Maximum 8-Hour Average

Ozone Concentration, 1993 Emissions.

1 NA indicated not applicable. No value exceeds 85 ppb.

of OCS emissions in any potential exceedances of the 8-hour ozone standard. Table 1C.2

summarizes the highest OCS contributions for the two episodes.

Southeast Texas

In the 17-20 August 1993 episode, the highest 8-hour average ozone concentrations occurred over

the Houston metropolitan area to the northwest of Galveston Bay. The highest simulated daily

maximum ozone values exceeded 85 ppb on all four episode days and reached a highest value of

111 ppb on 19 August. The highest OCS contribution to the daily maximum value was 7.3 ppb

at a location about 50 km from shore and where the total ozone concentration was less than

50 ppb. At those grid points where the daily maximum ozone value exceeded 85 ppb, the

highest OCS contribution was only 0.6 ppb, which is less than 1% of the total concentration. This

occurrence was over land; there were no points over water where the ozone concentration exceeded

85 ppb.

In the 6-11 September 1993, episode, the highest 8-hour average ozone concentrations occurred

over Galveston Bay and adjacent coastal areas. High ozone concentrations were found near the coast

and extending some distance offshore. The highest daily maximum ozone values were well over

85 ppb on all episode days and reached 203 ppb on 9 September. The highest OCS contribution to

the daily maximum value on 11 September was 16 ppb at a location about 50 km from shore and

where the total concentration was a little less than 80 ppb. At those grid points where the daily

maximum value exceeded 85 ppb, the highest OCS contribution was 11 ppb, which is about

12 percent of the total concentration. If one considers grid points on land only, the highest OCS

contribution was 5.5 ppb. The total concentration at that location was 86 ppb, so the OCS

contribution is about 6 percent of the total concentration. Figure 1 C. 1 illustrates the location and

magnitude of the OCS contributions along with the geographic extent of the area where the total

concentrations exceeded 85 ppb.

Southeast Texas

Highest OCS Contribution, ppb, at Locations

Where O Concentrations Exceed 85 ppb

Over Water Over Land

August Episode NA' 0.6 (<1%)

September Episode 11(12%) 5.5 (6%)

Louisiana

August Episode 15 (18%) 4.4 (5%)

September Episode 18 (20%) 4.7 (5%)
Figure 1C.1. Texas, 11 SeptemberOCS Contribution.

Louisiana

In the 17-20 August episode, the highest ozone concentrations occurred over the Baton Rouge area.

The highest daily maximum 8-hour ozone values exceeded 85 ppb on all episode days and reached

119 ppb on 19 August. The highest OCS contribution to the daily maximum 8-hour ozone concentration was 28 ppb at a location about 70 km offshore central Louisiana. The total ozone concentration

at that point was about 70 ppb. At those grid points where the daily maximum value exceeded 85

ppb, the highest OCS contribution was 15 ppb, which was about 18 percent of the total

87
88

concentration. This value occurred offshore east of the tip of the Mississippi Delta. If one considers

grid points on land only, the highest OCS contribution was 4.4 ppb. The total concentration at that

location was 85.4 ppb, so the OCS contribution was about 5% of the total concentration. This

contribution occurred on 19 August in the Mississippi Delta.

In the 6-11 September episode, the highest ozone concentrations generally occurred over southwestern Louisiana area. The highest daily maximum 8-hour ozone values exceeded 85 ppb on all

except the first two days of the episode; the highest value was 155 ppb on 10 September. The highest

005 contribution to the daily maximum 8-hour ozone concentration was 22 ppb at a location well

offshore southwestern Louisiana. The total ozone concentration at that point was about 80 ppb. At

those grid points where the daily maximum value exceeded 85 ppb, the highest OCS contribution

was 18 ppb, which was about 20% of the total concentration. This value also occurred well offshore

southern Louisiana. If one considers grid points on land only, the highest OCS contribution was 4.7

ppb. The total concentration at that location was 92 ppb, so the OCS contribution was about 5% of

the total concentration. This contribution occurred on 11 September, just inland of the south-central

Louisiana coastline.

COMPARISON BETWEEN 1-HOUR AND 8-HOUR IMPACTS

Table 1 C.3 compares the impacts based on the old 1 -hour standard with those relative to the new 8-

hour standard. It shows that for the Augustepisode in Southeast Texas, there were negligible impacts

relative to both the 1-hour and the 8-hour ozone standard. In the September episode, however, the

highest OCS contribution relative to the 8-hour standard was 5.5 ppb, while it was 3.2 ppb relative

to the 1-hour standard. For Louisiana, discernable differences are seen for both episodes. In the

August episode, the highest OCS contribution relative to the 8-hour standard was 4.4 ppb, while it

was only 0.5 ppb relative to the 1-hour standard. In the September episode, thehighest 8-hour OCS

contribution was 4.7 ppb, compared with a maximum 1-hour OCS contribution of 2.1 ppb.

SPATLA.L AND TEMPORAL CHARACTERISTICS OF OCS CONTRIBUTIONS

The new 8-hour ozone standard is more stringent than the old 1-hour standard. It is, therefore, not

surprising that the modeling simulations show that the size of the area where the 8-hour, 85-ppb

threshold is exceeded is significantly larger than that ofthe area where the 1-hour, 1 25-ppb threshold

is exceeded. This is true especially for Louisiana. Furthermore, there are more areas near the

shoreline where the model simulates ozone concentrations that are greater than 85 ppb, as compared

to the case where we consider 125 ppb asthe threshold. Nevertheless, there is little overlap between

areas that have high 0CS contributions and areas where the total concentration from all sources

exceed the 85-ppb threshold (See Fig. 1). Total concentrations are small in areas offshore, where

OCS contributions are greatest. In areas where total concentrations are largest, the OCS contributions

are small. There are relatively small areas where total concentrations exceed 85 ppb and where, at

the same time, there is some OCS contribution. As shown above, the highest calculated OCS

contribution for any onshore location where the 8-hour ozone level exceeds 85 ppb is 5.5 ppb, or 6

percent of the total concentration. This occurred inthe Southeast Texas subdomain on 11 September.
'NA indicated not applicable. No value exceeds the applicable threshold level.

89

Table 1 C.3. Comparison of 8-Hour and 1-Hour OCS Contributions to Daily Maximum Ozone

Concentrations.

To illustrate temporal characteristics, Figure 1 C.2 shows a time series plot of the 1 -hour average

ozone concentrations for same the grid cell. It shows that the peak 1-hour average concentration is

only about 90 ppb, well below the 1-hour standard of 125 ppb.

The OCS contribution to the peak value is only 2.0 ppb. After the peak is reached for the day, the

concentrations without OCS contribution drop off at a faster rate than those with OCS sources

included. The OCS contribution continues to rise through the afternoon hours and reaches a peak of

13.5 ppb at 1800 local time (LT).

Figure 1 C.3 shows the time series of the 8-hour running average concentration for 11 September at

the grid cell 54, 27 in the Texas subdomain (near Sabine Pass). The time shown in the figure is the

starting time of the running average. For example, the concentration for 1200 LT is the average of

the hours from 1200 through 1900 LT. The plot shows that, for the model run with the OCS

emissions, the peak 8-hour ozone concentration is just slightly above 85 ppb, while for the

simulation without OCS emissions, the peak is only about 80 ppb. When the OCS emissions are

included, there is about a 2-hour delay in the time that the peak is reached. The OCS contributions

keep increasing slowly with time, even as total concentrations decline and reach a peak of 11.4 ppb

at 1500 LI.

Highest OCS Contribution

to Daily Maximum Ozone

Over Water Over Land

Southeast Texas

August Episode

8-Hr 03>85 ppb NA' 0.6(<1%)

1-Hr 03> 125 ppb NA' 0.4 (<1%)

September Episode

8-Hr 03> 85 ppb 11(12%) 5.5 (6%)

1-Hr 03> 125 ppb 6.6 (4%) 3.2 (2%)

Louisiana

August Episode

8-Hr 03 > 85 ppb 15 (18%) 4.4 (5%)

1-Hr03>l2Sppb NA' 0.5(<1%)

September Episode

8-Hr 03> 85 ppb 18 (20%) 4.7 (5%)

1-Hr03>l25ppb 2.9(2%) 2.1 (1.5%)
90

100

90

. 80

70

60

50

:40

30

ç20

0 2 4 6 8 10 12 14 16 18 20 22 0

Local Time

- w/ OCS - - wlo OCS ...-.. OCS Contribution

Figure 1 C.2. 1 -Hour Average Ozone, 11 September 1993Grid Cell 52,27.

100

90

80

'70

--60

50

40

30

c-) 20

10 00

Figure 1C.3. 8-Hour Average Ozone, 11 September 1993Grid Cell 52,27.

I ..... I I I ] I I

--------- - -

.'--1'-'-- I ....I... 0 2 4 6 8 10 12 14 16

Local Time

wi OCS w/o OCS OCS Contribution
MECHANISMS AFFECTING OCS CONTRIBUTIONS

The dominating influence in onshore OCS contributions to ozone levels in the study region is that

of recirculation and offshore pooling of ozone and ozone precursors. During ozone episodes in the

Gulf coast region, prevailing winds are very light, and the atmosphere is stable. Local wind

circulations induced by differential heating over land and water are dominant. These features are

most pronounced over coastal Texas, and a little less so over Louisiana. The land breeze establishes

itself after midnight. It starts weakening after sunrise, and winds become light and variable by late

morning or noon. The sea breeze starts shortly after noon and gains strength throughout the

afternoon; it normally lasts through the evening.

Ozone precursors from onshore sources are carried offshore in the morning land breeze. These emissions start to interact as solar radiation increases through the day and generate ozone. Additional

ozone may be formed by interaction with OCS sources. The ozone is then recirculated onshore with

the afternoon land breeze. However, when the sea breeze is strong, as in the August episode for

Southeast Texas, the pollutant mass is centered some distance inland, and OCS contribution is

minimal

The September episode for Southeast Texas was different. A series of weak cold fronts from the

north kept the daily sea breeze from penetratingvery far inland. Ozone levels built up near shore and

some distance offshore, allowing an opportunity for already polluted air masses to spend time over

the Gulf entraining OCS emissions. When the air mass was finally circulated back to shore on the

last days of the episode, the model simulated OCS contributions whenozone levels exceeded 85 ppb.

Examining again the peak OCS contribution at grid point 54, 27 on 11 September, the observed

surface wind data at a nearby monitoring station revealed that winds were offshore from about

midnight till about 1100 LT, at which time the winds shifted to southeasterly and then southerly

directions, which then lasted through midnight. A trajectory analysis (not shown) indicated that

precursor emissions from the OCS bad been picked up off Southwestern Louisiana on thatsame day

as well as on the previous day. This particular OCS area has a fairly high density of emissions.

Time series plots (not shown) for points some distance from shore off Southeast Texas showed a

steady buildup of ozone from the background concentrations of 40 ppb to a level of about 85 ppb

over several days. Most of this buildup was from onshore ozone precursors. OCS contributions were

about 10 to 15 ppb. It should be noted that OCS contributions by themselves are never enough to

cause the concentration to exceed the 85 ppb threshold. It takes a combination of onshore and OCS

emissions to have concentrations exceed the new standard. When the pollution mass that had been

pooling offshore eventually reached shore with the sea breeze, it caused the 85-ppb threshold to be

exceeded, with part of the concentration being attributed to OCS emissions.

The same mechanism of recirculation and pooling was evident in Louisiana. However, the flow

had more of an east-west component, and trajectories followed a less direct path. Onshore impacts

from OCS emissions were attributed to OCS emissions pickedup the day before rather than the same

day.

91
92

DISCUSSION OF CAVEATS

A number of different factors make it possible for us to interpret the results only qualitatively. First,

the emissions used in the UAM-V modeling are for the year 1993. Emissions for the year 2000

baseline will be different. Furthermore, one would need to consider projected emissions beyond the

year 2000 if the modeling results are to be applied to any future control strategies to be developed

in the year 2003. Second, the episodes that were used in the analysis were selected based on the old

1-hour ozone standards. If one were to base ozone modeling on the 8-hour standard, the suite of

episodes available for analysis would likely be different.

Third, there are uncertainties in the calculated OCS impacts. These impacts were determined by

taking the difference between two sets of model runs, both of which are subject to errors. These

errors may be magnified by subtracting one data set from another. Since the calculated OCS impacts

are small relative to the total contribution from all sources, the magnitude of these impacts is subject

to uncertainties. Finally, one must not place too much confidence in the location of predicted

impacts. Variations in the wind field used can significantly influence the location of predicted

maxima.

CONCLUSION

This study showed that the effects of OCS emissions relative to the new 8-hour standard are larger

than those relative to the former 1-hour standard. The largest OCS contributions tended to be at those

locations where the predicted concentrations were just above 85 ppb. The area of impact on any

particular day tends to be rather small. An analysis of the wind field indicated that recirculation and

offshore pooling tended to play a major role in generating any OCS impacts onshore.

There is clearly a need to conduct additional work to evaluate OCS impacts on the new 8-hour

standard. This would involve (1) updating the emission inventory for the OCS in the Gulf of Mexico,

(2) determining appropriate episodes for modeling ozone relative to the 8-hour standard, (3)

conducting modeling analyses to quantifi OCS impacts, and (4) developing criteria for determining

significance of OCS impacts (perhaps the most challenging task).

REFERENCES

Federal Register, 1997. Environmental Protection Agency, National Ambient Air Quality Standards

for Ozone; Final Rule, Federal Register, Vol. 62, No. 38, 18 July 1997.

Minerals Management Service, 1995. Gulf of Mexico Air Quality Study, Final Report, UCS Study

MMS 95-0038, 3 Volumes, August 1995.
INTERCOMPARISON OF AIR POLLUTANT DISPERSION MODELS

Dr. Mark E. Fernau

Mr. Joseph C. Chang

Mr. Joseph S. Scire

Mr. David G. Strimaitis

Earth Tech, Inc.

Concord, MA

The Minerals Management Service (MMS) uses different types of air dispersion models to perform

tasks such as environmental impact studies and regulatory analyses to regulate the activities of

offshore operators. The MMS would like to expand the current suite of air quality models used to

ensure that MMS' model selections are scientifically credible and can withstand possible critiques,

a critical review of the following four types of air quality models is necessary:

Regional-scale dispersion models for applications where phenomena such as advection,

deposition, and potential chemical transformations of pollutants are important on a spatial

scale up to 1,000 km. Eulerian photochemical grid models might be best for this purpose.

Lagrangian trajectory (puff) models for instantaneous and short-duration emissions, or for

releases when spatially-varying meteorological fields are important.

Toxic release models for analysis of consequences of accidental releases of hazardous

pollutants.

Steady-state Gaussian models for general review of offshore operator's plan when the

source-receptor distance is less than 50 km or so.

Based on MMS' needs, we considered the following six major model evaluation categories, where

some of the categories were further divided into a number of subcategories or attributes:

Science arid Credibility

Al .Technical and general descriptions

A2.Grid options for Eulerian and trajectory models

A3.Quality of physical processes simulated

A4. Sparse data treatment

A5 .Overwater dispersion

A6.Model evaluation history

Ease of Use (From User's Perspective)

B1.User's guide

Model Options

Data preparation time

93
94

B4. Ease of data acquisition

B5.Model interfaces to preprocessors / GUI

Run-time diagnostics

Post-run diagnostics

Computational Requirements

Cl. Multiple sources

C2.TINIX / PC portability

C3.Run time

C4. Code flexibility and readability

Cost

Availability / Restrictions / Terms

Language for Model and GUI

Only Categories A, B, and C were used to rank the models, where a score from 1 to 3 was assigned

to each attribute. 3good, very flexible or state-of-the-art; 2=fair, less flexible, or somewhat out of

date; and 1 =poor or not flexible. Categories D, E, and F are for information only. To account for

varying degree of importance, we further assigned a weight to the score for each attribute. The attributes for Categories A and B have a weight of 2; the attributes for Category C have a weight of 1.

We then designed a normalized model score (0 to 100%) based on the summation of weighted scores

over all applicable attributes divided by the summation of weighted highest possible scores over all

applicable attributes. This normalized score was then used to produce the final model ranking

The current review is not intended to be comprehensive. Instead, four to seven representative"

models in each model category (except for steady-state Gaussian models, see below) were chosen

for review, and the top two to three in each category are then recommended. The omission of a

model does not mean in any way that the model is inferior or less desirable. For steady-state

Gaussian models, we limited our review to the technical components in the Offshore and Coastal

Dispersion (OCD) model, which has been a regulatory model used by the MMS.

The evaluation mainly consisted of reviews of the user's guide, technical documentation, peerreviewed journal articles, conference proceedings, web pages, and the source code for each model.

Model developers and users were interviewed if necessary. This study is not a formal performance

evaluation, where the model results are compared against field data.

The following list gives the models that were chosen for evaluation along with the scores that they

received in the review:

Regional-scale dispersion models:

CALGRTD 74.4% -

CAMx 74.4% -
SAQM 60.0%

UAM-IV 57.8%

UAM-V 83.3%

Lagrangian trajectory models:

CALPUFF 93.3%

HYSPLIT4 88.3% -

INPUFF 63.5%

MESOPUFF II 77.8%

SLAM 77.6%

Toxic release models:

- BREEZE I-IAZ SUITE (GUI only)

SLAB View (GUI only)

SLAB for Windows (GUI only)

93.3% -

84.6%

74.4%

95

The models marked by arrows are our recommendations based on the above evaluation criteria and

methodology. These models were recommended mainly because of their high technical qualities,

relevance to MMS' special needs (e.g., overwater dispersion, multiple sources, and environmental

impact studies), and proven track records. The two graphical user interface (GUI) programs,

BREEZE HAZ SUITE and SLAB View, were recommended because of their state-of-the-art design,

ease of use, and value-added features such as source term calculations and graphical functions.

In the report, we made various recommendations for the Offshore and Coastal Dispersion (OCD)

model in technical areas such as the overwater mixing height, parameterizations of the marine

boundary layer, the use of overland meteorological data, the vertical dispersion coefficient, the

thermal internal boundary layer, multiple land and water transitions, and impacts on offshore areas

due to coastal sources. Recommendations were also given in operational areas such as the shoreline

database and the documentation. We caution that while it is relatively easy to upgrade the OCD code

to incorporate new theories and algorithms because of OCD's modular design, any changes must be

subject to careful evaluation. Some of the important issues to consider include (1) whether the new

algorithms are physically meaningful; (2) how the new algorithms affect predicted concentrations;

(3) potential cancellation of errors; (4) whether the new algorithms are robust enough so that they

will always succeed when running with, for example, one year of data; and (5) whether the new

algorithms require data that are always readily available.

AFTOX 66.7%

ARCHIE 79.4%

CANARY 84.1%

DEGADIS 81.8%

HGSYSTEM 87.9%

SLAB 86.7%

TSCREEN 68.9%
96

Dr. Mark E. Fernau (J)resenter) has worked in the Atmospheric Sciences Group at Earth Tech for five

years as a Senior Scientist; before that, he worked in the Environmental Policy Group at Argonne

National Laboratory. He has over 15 years of experience in the application of grid-based

photochemical models and trajectory-based long range pollutant transport models to address

scientific and policy issues. He has exercised the CALGRID, UAM-IV, UAM-V, SAQM, CAMx,

ROM and RADM models on various regional, Northeast, California, Canadian and Midwestern

domains, and has extensive experience in all aspects of running these models. Dr. Fernau received

his B.S. from Cornell University and M.S. and Ph.D. degrees from the University of Michigan, all

in atmospheric science.

Mr. Joseph Chang has over 10 years' of experience in the development of numerical models, data

analysis, model evaluation and the atmospheric boundary layer. He is the Manager for Model

Development and Analysis at Earth Tech, Inc. He is a specialist in toxic release modeling. He

received his B.S. at the National Taiwan University and his M.S. degree at the Massachusetts

Institute of Technology and is a Certified Consulting Meteorologist.

Mr. Joseph Scire is a Vice President and the Manager of Earth Tech's Atmospheric Sciences Group.

He has played a major role in the development of several widely used models including BLP,

MESOPUFF II, and CALPUFF, and parts of the ISC model. He has B.S. and M.S. degrees from the

Massachusetts Institute of Technology.

Mr. David Strimaitis is a Principal Scientist at Earth Tech, Inc. with over 18 years' experience in

developing and evaluating air quality models. He has participated in the development and evaluation

of many of EPA's regulatory models, as well as CALPUFF. He received his B.S. from Trinity

College and his M.S. from the Massachusetts Institute of Technology.

PROJECT STATUS REPORT: EMISSIONS INVENTORIES OF OCS PRODUCTION

AND DEVELOPMENT ACTIVITIES IN THE GULF OF MEXICO

Mr. Lyle R Chinkin

Sonoma Teclmology, Inc.

INTRODUCTION

The purpose of this work effort, "Emission Inventories of Outer Continental Shelf (OCS) Production

and Development Activities in the Gulf of Mexico" (MMS Contract No. J-30856) is to provide

technical support for the development and maintenance of MMS's current and past-year (1977 and

1988) emission inventories for the OCS. The project team is developing and revising the

softwaretools that will be used to collect and manage the emission inventories, including a PC-based

database management system (DBMS), and the survey software originally developed by the MMS

(AEIS) to query offshore operators regarding platfonn activity. Begimiing in 1999, the project team
97

will work cooperatively with the MMS to survey the offshore platform operators and compile

emissions activity data. These data will then be used to prepare spatially distributed OCS emission

inventories of primary air pollutants (carbon monoxide, NON, SOS, total suspended particulates,

PM10, PM25, total hydrocarbons, and volatile organic hydrocarbons). Area and mobile sources will

be spatially resolved to the grid cell level, and point sources will be assigned specific coordinates.

A portion of the slide show that accompanied this presentation appears at the end of the article.

PROJECT BACKGROUND

The determination of the BNWA's PSD status depends upon regional air quality modeling. In turn,

modeling results depend upon the qualities of the model algorithms, meteorological input data, and

emissions input data. To improve the quality of the inputs, the MMS issued a Notice to Lessees

(NTL No. 96-04, dated 15 August 1996) that required Outer Continental Shelf(OCS) leaseholders

within 100 km of BNWA to collect and submit meteorological, air quality, and emissions data. In

response, the Offshore Operators Committee (OOC) recently initiated the Breton Aerometric

Monitoring Program (BAMP) to collect air quality, meteorological, and emissions information. The

current project will provide the MMS with a new OCS gridded emission inventory for the BAMP

monitoring period, backcast inventories for the PSD baseline years (1977 and 1988), and software

tools that will facilitate maintenance of these inventories.

WORK PLAN

The critical tasks for this project fall under two related categories, software development and

inventory development. Software development tasks include work on the AEIS software and DBMS.

Inventory development includes data gathering, QAJQC checks, and emissions modeling for current

and past years.

Software Development Tasks

Recently approved as a project add-on, the initial software development task is a revision to MMS's

AETS software program. AEIS is a PC-based, interactive software program designed to query

offshore platform operators and record their responses as emissions activity data. Operators will

submit these data to the MMS for later use during Inventory Development. The purpose of revisions

to AEIS is to minimize the likelihood of user-input errors. Revisions will include automated quality

assurance and quality control (QAJQC) features that will assist users to enter correct and complete

data. Initially, the project team will work together with MMS ' s Information Technology (IT) staff

and, if possible, with software users to finalize the scope of the software revisions. Following

implementation of the revisions, the project team will turn the AETS product back to MMS IT staff

and software users to aid with product testing. The projectteam intends to conduct a pre-test of AEIS

with four to six operators, and a full test for one to two months prior to the start of BAMP.
98

Under this contract, the project team is also developing a database management system (DBMS), a

tool that will facilitate maintenance, review, and updates to the repository of OCS emissions data.

Functions of the DBMS will include:

Automated QAJQC functions

Emissions calculations

Updateable default parameters and emission factors

Summary statistic calculations

Selection queries

Geographic data display (via an ArcView interface)

Report generation

The DBMS will be the primary tool used to accomplish inventory development tasks, such

as QAJQC, emissions calculations, and data archival.

Inventory Development Tasks

Inventory development efforts for historical years 1977 and 1988, will address thesource categories

listed in Table 1 C.4. The historical inventories will be prepared for the entire Gulf of Mexico. An

Table 1 C.4. OCS emission inventory source categories.

Source Category Source Description

Platform Sources Plafform Equipment

-engines and turbines

-storage tanks

-flares

-glycol regenerators

-vents

amine units

-fugitive emissions

-petroleum loading/unloading

Platform-Associated

Sources

Crew/Supply Boats

Oil Barges

Shuttle Tankers

Tugboats

Research Vessels

Crew Helicopters

Construction Barges

Pipeline Sources Pipeline Construction Equipment

-pipeline barges

-tugboats

Exploration & Drilling Drilling Equipment

-Engines and Turbines

-Mud Degassing
Figure 1C.4. Flow of information during development of the current-year inventory.

99

t.. 1_li,

Distribute QA reports '4

Operators Request corrections

Individual

Data bases

MMS

Merge Data

Activity

Database

Data

Archive

DBMS

_Generate QA report

QA activity data

Calculate emissions

QA Report

QA emissions

Archive all data
100

analysis of the current-year inventory will serve as a starting point for the backeasting process. The

project team will adjust the current-year inventory according to historical events, such as

commissioning or decommissioning dates, growth or decline in production rates, the addition of

emissions controls, and the introduction of new technologies. When past-year data are unavailable

for historically active emissions sources, the current-year inventory may be extrapolated to estimate

past-year emissions for these sources. Data uncovered to date include records of platform

installations! decommissions, platform equipment lists, pipeline installations, and drilling activities.

The current-year inventory will be concurrent with the BAMP study period. The inventory will be

based on MMS's AEIS survey of those facilities within 100 kilometers of BNWA (per NTL 96-04).

Thus, it will include those sources listed as "Platform Sources" in Table 1C.4. If irreducible errors

are discovered during QA/QC, the project team will bring the suspected errors to the attention of the

MMS. The MMS will verify the suspected errors and forward corrections to the project team.

Figure 1 C.4 illustrates the anticipated flow of information between offshore operators, MMS, and

the project team during the compilation of the current-year inventory. The project team anticipates

receipt of AEIS survey data at monthly intervals over the course of 14 months, beginning in the

spring of 1999. Upon a successful QA!QC evaluation, the project team will estimate emissions and

archive the activity and emissions data for each source.

PROJECT STATUS

This project is somewhat delayed due to changes in schedule and scope precipitated by delays in the

BAMP study schedule. The project team is cautiously moving forward with most tasks, including

scoping the design of the DBMS and AEIS revisions, technical research into QA!QC protocols, and

historical data collection. It is anticipated that current-year data collection will begin in the spring

of 1999. The key deliverables (final electronic inventory files and software products, including

source codes) will be handed over to MMS 18 months after the start of the BAMP study.

Minerals Management Service

tonttIn Oftly.r. WnII.y. MOO/i Contrecilno Ofliyei'n Teyhns.I Rop,.00ntotiin. vi.so LUOo.Fnendoo Cc-Principal Investigator Lilt Chy,kin

(CT)) Ca-Principal InvestIgator Murk Yocko Unv,rrr Technical Review Scard Emisnions Presenting & Emissions SoTtwore Design Database Matagtninflt 0.1k/SO/i. (ENVIRON> Projen Manager LyI.RCflhOd/i (91-)) Mt/S CSp'o ENS/i/il Loin U UhIr(dr IS/il Lyin SI. Cl/inS/in Emissions Estimation end Dackcanflng Emission, Data Collection OA Officer Lye II 5,15/in (SrI) 5 Ovo/in low In ON) MISSY/ink. is/ill/tin Erecmoi (iolhI.k. ErSIrmIe) AE1S Upgrades & Ocociop User's Guide

lyle/S O,I,,ki, 1ST)) ocr Ctpitro (ENSOUl

50/99 Ce-Principal Investigator Lii. 0. ShIeld,, (Sn) Ceerinnipal investigator &

Quality Central Officer DeS Vt/ike

(anwon) STI V7199 57

Key Participants Key Participants (conttd)
101

Project Overview

Objective: Provide technical support for

development of current and past-year

gridded OCS emission inventories.

Generate spatially resolved emission

inventories.

Develop software that facilitates ongoing

management and updates to the emission

inventories.

917/99 577

Work Plan

Software development

Revise the AEIS data collection software.

Develop database management system

(DBMS).

Emission inventory development

Generate a current-year OCS inventory

IJseAEIS and DBMS to:

-Gather, ingest, and QA survey data

-Estimate and QA emissions.

-Archive all data.

-Return QA reports to MM5 and platform operators.

'Sill

reton National Wilderness

Class I air quality designation

SO2 & NO2 increments consumed?

Many stakeholders

Air quality models questionable

325 OCS facilities within 100 km

Initiated RAMP /

This project: Emissions data for BAMP

and baseline periods

817/79 Sn

Work Plan

Emission inventory development (cont'd)

Historical inventories (1977, 1988)

- Acquire historical activity data.

Combine current inventory and historical data

in order to backcast past-year inventoriea

Archive data

9/7199 Sri

Software Development

AEIS Revision

Objective: Reduce the likelihood of userinput errors during the AEIS survey.

- Introduce preliminary QA checks

- Improve the user interface

DBMS Development

Objectives: Facilitate updates, reviews,

and maintenance of OCS inventories.

Editable tables of emission Ictors

- Data review & display functionalities

Software Development

Steps

Thoroughly scope out the functionalities

and graphical user interface (GUI)

Perform supporting engineering &

technical research

Software implementation

4 Software testing

917199 sri '9
102

OCS Emissions Estimates

Emissions Estimation

Direct Measurement

E.F.xA

Spatial & Temporal Distribution

Source Categories

Transportation & Shipping

Fugitives

Storage Tanks & Loading

OCS Facility Processes & etc.

577 /4

OCS Emissions: Unique Issues

Daily variation in production quantities

Temporary activities (e.g., drill rigs, etc.)

Difficult to access direct emissions

measurements

High labor costs

Electricity demand

Cnnstruttion

Database Management Issues lof2

Relational database standards

Graphical User Interface (GUI)

On-the-fly QA/QC checks

Data entry

Easy access & display of data

Automated reporting

Queries

Sf190 577

Database Management Issues 29(2

Updatable automated estimation methods

Statistical tools to aid QNQC

Updatable default values

Future modifications

Data security

User's Guides

917199 12

Inventory QAIQC Procedures

Human-eye checks

Data formatting & units

Graphical data displays (automated)

Statistical analyses (automated)

Site visits

QAIQC provides a realistic perspective on

the inventory.

577 IS

OCS Inventory Uncertainties

Currently unquantified

Uncertainty analysis tools

Database management utilities

AEIS error checks & utilities

Statistical uncertainty analysis

Examine unusual facilities (eg, site visits)

517/99 Sn IS
103

Mr. Lyle R. Chinkin, Vice President of Emissions Assessment with Sonoma Technology, Inc., is

responsible for the strategic planning of emissions studies and preparation of emission inventories.

During his 20-year career in the air pollution field, he has focused on issues related to emission

inventories and air quality. Mr. Chinkin's contributions to the field include recommended guidance

to improve the California Air Resources Board's (ARB) emission inventory methods and an EPA

guidance document regarding the preparation of gridded emission inventories for air quality

modeling. Mr. Chiukin possess B.S. and M.S. degrees in atmospheric sciences from the University

of California - Davis.

Historical Data & Backcasting

Examine each category for historical data

Regulatory changes

Technological changes

Update with surrogate activity data

Production volumes

Employment figures

t7/09 Sn l0

Project Status

Tasks Underway

AEIS Revision

Historical Data Collection

QA Supporting Research

Note, some tasks are slowed or delayed

due to changes in the BAMP schedule

and related changes to project scope.

Sri 20

Where do we go from here?

Complete software development by

Spring 1999.

Collect current-year inventory data from

Spring 1999 until Spring 2000.

Allow 6 months to complete data

processing, QA, and backcasting.

Deliver draft inventory files and software

(md. source code) by Dec. 31, 2000.

IST/
104

DISPERSION METEOROLOGY OVER THE BRETON

NATIONAL WILDLIFE AREA (BNWA)

Dr. S.A. Hsu

Louisiana State University

INTRODUCTION

In June 1997, surface meteorological measurements at our Breton Island air quality station were

enhanced by the addition of water temperature and a pier-mounted UVW wind system. Wind

turbulence data was collected at 30-minute intervals through July 1998; approximately 5 weeks of

data was lost following passage of Hurricane Danny in July 1997. This brief report will summarize

several preliminary findings related to stability and dispersion characteristics over the Breton area

(including nearby NOAA buoys and C-MAN stations) and present a method for estimating mixed

height from remotely-sensed (satellite) data.

METHODS AND RESULTS

Atmospheric stability may be characterized by Z/L formulation such that

KCC;2R (1)

where lc = 0.4, CT 1.1 x 1 O, Rb is the bulk Richardson number (Hsu 1992), and Cd is based on the

wind-wave interaction method (see, e.g., Hsu 1995) for the buoy data. However, since no wave

measurements were made at Breton or C-MAN station GDIL1, a second Cd formulation provided

by Hsu (1995), which is dependent only on wind speed, was employed for the land-based stations.

Hourly values of Z/L were calculated for NOAA buoys 42007 and 42040 and C-MAN GDIL1 as

well as at Breton. Stability was classified as unstable for Z/L < -0.03, neutral for IZ/LI 0.03, and

stable for Z/L> 0.03. Figure 1C.5 shows the frequency of occurrence for each category. Breton

Island stability characteristics most closely resemble those at buoy 42007, particularly for unstable;

therefore this station's long-term record may be used to simulate conditions over the BNWA. Note

that the larger percentage of stable conditions at Breton may be due to chilling of the shallow waters

in the Sound.

High concentrations of pollutants may be anticipated if a release occurred during very stable

conditions offshore. Stable mixed height may be approximated by (Panofsky and Dutton 1984)

hibi = 0.4\ u L

f

(2)
where f 2 sin p. From Hsu (1998), when Tair> Tsea (stable),

L U*CpPTir

i g I!

where H5 (sensible heat flux) = PCpCT(Tsca - Tair)Uio. Substituting back into Eq. (2) and reducing

0.4 C U

T

fKgC(T,r - (4)

Employing the WAMDI (1988) formulation for Cd, Figure 1C.6 shows that an estimated mixed

height of only 104 m was found under an episode of stable conditions at buoy 42007.

Turbulence intensity data observed under near-neutral conditions (IZ/Lj <0.4) at Breton Island was

compared to relationships found for the North Sea (Geernaert et al. 1987) and North Atlantic (Smith

1980). Data observed under light wind conditions (U10 < 5 mIs) were excluded to better represent

stability class D (neutral) conditions (see, e.g., Zannetti 1990). In Figure 1C.7, good agreement is

found for downwind (ou) and vertical (nw) intensities; however larger crosswind (v) intensities are

seen in this data set. Further defining these relationships is essential for proper ciy and z calculations

in dispersion modeling efforts over the BNWA.

New satellite systems scheduled to come online will provide accurate measurements of surface and

cloud-top temperatures as well as heights of cloud tops. Figure 1C.8 demonstrates a method for

determining the mixed height from this remotely-sensed data. The computed LCL, or mixed height,

from a radiosonde profile recorded at Breton Island on 4 August 1998 (Figure 1 C.9), is shown to be

in excellent agreement with that obtained from the satellite data.

CONCLUSIONS

Unstable conditions were observed at Breton Island during over 60% of the period from May 1997

through July 1998. Stability and disperison characteristics at Breton and NOAA buoy 42007 appear

well-related; hence the long-term buoy record may be used to represent conditions in the BNWAas

a first approximation. When stable conditions exist, mixed heights can drop to 100 m or less. Good

correlation of downwind and vertical turbulence intensities is found between Breton Island data and

that from the literature; however, larger crosswind intensities were observed. A method for

estimating the mixed height from remotely-sensed data is demonstrated with excellent results.

105

(3)
106

Unstable

Neutral

Stable

0

I

May 1997 Through July 1998

Breton Island (75% Complete)

GDIL1 (955°4 Complete)

Buoy 42007 (779% Complete)

Buoy 42040 (9311⁄4 Complete)

Stability Cherfieteristics

200

Figure 1C.5. Frequency of occurrence of stability classes for three NOAA stations and Breton

Island during the period of May 1997 through July 1998.

1000

900 Stable Mixed Height Colculatlon Cd Based On WAIVEDI Formulation I F - Tlr19.0°C SU0 - F

LocatIon: Buoy 42007, Chandeleur Sound F

700 January1998 T,.-T=S.0°C

B U1061m/S 600

SM:HApprou1O4m

=

500 -

F

/ 400 -

F

F

300 F

200

100

r;( F

F

6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

U0, rn/s

Figure 1C.6. Stable mixed layer height nomogram for air temperature of 19°C. Lines indicate

temperature difference (Tair - Tsea).

I I I I I 10 20 30 40 50

Vo Occurrence

60 70 80 90
107

Bruton L,h.nd

June 1997 July 1998

IZILI . 0.4

00723 -f 0.0024 t o, R 0.35 I_rio +

Figure 1 C.7. Observed turbulence intensities at Breton Island compared to relationships found for

the North Sea and North Atlantic.

RAOB BJ18.'LI DAT ..' flIH Ci fldIir

iI / . IC

I

I

I

I

ir1 /III I 'L1l' Iv1v1

. \ \ I

I

i

l

iv

I

v 4 . ':&. N/ / )/ / J / v' ;/ v - t

1/ / /

,.v /l/ ' v/!vt vN I

_ t / /

*_ )

/

/ / v /

i

v

Iv1I11I1 /

v /

/ l v9 _/_/_?v.*t/./._ v v 1' /7 J I

I

I 11v - - -v_j ( -_

1v L

'/'A J -v -

/ ;vv/ '/ /; - v Stratogti,,tt1 tts Ctt.tt1 lAS Conwes ttt CttI.,ttl fl Ii*j:tts

Figure 1 C.8. A demonstration of LCL (mixed) height from cloud-top temperature using data obtained over Breton Island on 4 August 1998 at approximately 1500 GMT

(1000 LT).
108

iPj - - - II_II __________

- I,

Figure 1C.9. Cloud-top temperature at approximately 16 degrees C.

REFERENCES

Geernaert, G. L., S. E. Larsen, and F. Hansen. 1988. Measurements of the wind stress, heat flux, and

turbulence intensity during storm conditions over the North Sea. J. Geophys. Res., 92(C 12):

13127- 13139.

Hsu, S. A. 1992. An overwater stability criterion for the offshore and coastal dispersion model.

Bound.-Layer Meteor., 60(4):397 - 402.

Hsu, S. A. 1995. A proper wind-stress drag coefficient formulation for computer modelling ofseas

and coastal regions, pp. 413 -420. In C. A. Brebbia, L. Traversoni, and L. C. Wrobel (Eds.).

Computer Modelling of Seas and Coastal Regions IL Boston: Computational Mechanics Publications.

Usu, S. A. 1998. A relationship between the Bowen ratio and sea-air temperature difference under

unstable conditions at sea. J. Phys. Oceariogr. 28 :2222 - 2226.

Panofsky, H. A. and J. A. Dutton. 1984. Atmospheric Turbulence. John Wiley. 397 pp.

Smith, S. D. 1980. Wind stress and heat flux over the ocean in gale force winds. J. Phys. Oceanogr.

10:709 - 726.

a.

a : a

A

A I
Dr. S. A. Hsu received his Ph.D. in meteorology from the University of Texas at Austin. He has been

a professor at Louisiana State University since 1969. His research interests are coastal and marine

meteorology, air-sea interaction, and pollution transport physics. Dr. Hsu has published extensively,

including a textbook entitled Coastal Meteorology.

THE BRETON AIR QUALITY STUDY/BRETON

AEROMETRIC MONITORING PROGRAM

Dr. Stephen D. Ziman

Chevron Research and Technology Company

Richmond, California

INTRODUCTION

This paper describes both the history and process by which aprogram has been developed to collect

a meteorological and air quality data base within 100 kilometers of the Breton National Wildlife

Area offshore of Louisiana and Mississippi. The proposed network and rationale are described. Uses

for the data include: a) limited evaluation of different air quality model formulations; b) assessment

of impacts on the Breton National Wildlife Area for Prevention of. Significant Deterioration Class

I increment consumption for the short-term 502 increments; c) data analysis leading to a better

understanding of the high SO2 impacts at the BNWA and, d) anduse in Environmental Assessments

and Environmental Impact Statements.

BACKGROUND

In early 1994, U.S. Fish and Wildlife Service (FWS) determined that there was significant possibility

of an exceedance of the Prevention of Significant Deterioration Class I SO2 three-hour and 24-hour

increments at the Breton National Wildlife ReftTge (BNWA) due to large short term releases of SO2

from a facility near Breton Island in 1993. FWS, the Federal Land Manager for the area, expressed

this concern to the Minerals Management Service (MMS), which has responsibility for regulating

air quality in the Outer Continental Shelf.' To address this issue, FWS concluded that a study was

'Meeting between MMS and Offshore Operators Committee, 12 December 1993.

109

The WAMDI Group. 1988. The WAM model - a third generation ocean wave prediction model. J.

Phys. Oceanogr. 18:1775 - 1810.

Zannetti, Paolo. 1990. Air Pollution Modeling. Van Nostrand Reinhold. 444 pp.
110

needed to carry out a cumulative air quality assessment of impacts from surrounding offshore and

onshore sources within a 100 kilometer radius of the BNWA. MMS undertook the study, and a

Technical Review Group under MMS leadership was established.2 The group included

representatives from National Park Service/Fish and Wildlife Service, EPA and the Offshore

Operators Committee. That group drafted a statement of work for the Breton Air QualityStudy. The

intent of the study was to design an air quality/meteorology/emissions inventory data collection

program suitable to evaluate a set of air quality models for their predictive ability; and to use one or

more of the models to determine increment consumption at the BNWA.

In 1996, the program was split into two parts, with concurrence of all parties. The data collection

effort would be funded by the Offshore Operators Committee and was renamed the Breton

Aerometric Monitoring Program (BAMP). The modeling would still be done by MMS. The

Technical Review Group for the BAMP was expanded to include representatives from the state

environmental agencies for Louisiana, Mississippi and Alabama, as well as representatives from

onshore industries in those states. In early 1997, MMS issued a Notice to Lessees (NTL)3 that

formalized the mandate for data collection offshore under the requirements of the OCS Lands Act.

BRETON AEROMETRIC MONITOR1NG PROGRAM

In early 1997 the revised and expanded Technical Review Group issued a Request for Proposals for

the BAMP,4 and awarded a contract to develop a phased approach to do the work. The first phase

had three components, which are described below. The second phase would be implementation of

the actual data collection program over a one-year time frame. Phase 1 has been completed.

Decisions on the scope of phase 2 have not been finalized. However, due to questions of funding,

an alternative scope for a network limited to the OCS has also been developed.

PHASE I EFFORTS

This phase had three components. The first component of this effort had three major tasks. The first

task was review of the pertinent air quality and meteorological models that might be considered for

assessment of increment consumption. The second task was the development ofa conceptual model

of the meteorological and air quality processes that are associated with high SO concentrations at

the BNWA. This task was dependent on climatological analysis of the periods associated with the

high SO2 concentrations. One of the problems confronting the analysts was the lack of sufficient

aerometric data in the offshore area. Only a single year of surface meteorology and ambient air

2Letter of 18 November 1994 from Acting Regional Director, MMS, Gulf of Mexico OCS Region to prospective

members of the Technical Review Group.

3Notice to Lessees and Operators of Federal Oil, Gas and Sulphur Leases in the Outer Continental Shelf, Gulf of

Mexico OCS Region 97-02, Meteorological Data Collection (Breton National Wildlife Refuge/Wilderness Area, 23

January 1997.

4Request for Proposal for Breton Air Monitoring Program, Offshore Operators Committee, 26 March 1997.
111

quality measurements were available at Breton Island. The final taskwas a set of recommendations

for monitoring that would meet the needs for both modeling and analysis. One major outcome of this

last task was the realization that a rigorous evaluation of the air qualitymodeling system was practically unattainable because of cost considerations. Evaluation of plume dynamics would require a

very dense network of surface monitors, as well as monitoring aloft. Much of this network would

have to be over water. Therefore, a decision was made to emphasize a network that, from a

meteorology perspective, would improve the modeling system's handling oftransport. Most of the

recommendations support acquisition of continuous surface and aloft meteorological data.5

The second component was the assessment of the emissions inventory that would be needed to

provide input into any air quality modeling simulations. This task identified various portions of the

inventory, significant gaps in the inventory, especially with respect to mobile sources onshore and

offshore, and area sources. Based on the initial assessment and in conjunction with the initial driving

force for the study, emphasis was placed on improvements in the 502 inventory.6

The third component synthesized the information in the first two tasks, incorporated additional data

analysis, and provided a set of options for the proposed BAMP network.7 The second option, which

will be described below, met most of the overall goals of the Technical Review Group. However,

the Technical Review Group also sought an independent review of this option. That review

concurred with and enhanced the conceptual model upon which the option was developed.8 This

option emphasizes a program that is intended to improve our understanding of the flow dynamics

and air quality associated with high SO2 concentrations at Breton Island. The bases for the proposed

network are derived from the above components:

Surface wind speeds are relatively high and are from northwest to northeast

Higher-than-normal temperature variations occur and lower-than-normal mixing heights and

neutral to stable dispersion conditions occur.

These conditions are associated with two meteorological regimes, a Continental High and

Frontal Overrunning, that are dominant in winter, when most of the high SO2 concentrations

occurred.

Those meteorological regimes may result in a regional plume capable of reaching the BNWA

over an extended period of time.

5Tesche, T.W. and McNally, Dennis Recommendations for Air Quality Dispersion Models and RelatedAerometric

Data Sets in Support of the Breton Air Monitoring Program. Task I Final Report, Alpine Geophysics, AG-9OITS 107, 28 February 1998.

6Lee, Edward, Final Draft Report. Task 2-Emissions Inventory Identification and Assessment for Offshore

Operators Committee, Walk-Haydel, WH 37598-001-2001, 6 March 1998.

7Preliminary Draft Report, Task 3: Design of the Breton Aerometric Monitoring Program, Walk-Haydel, Dames

and Moore Project No. 35610-007-140, 14 April 1998.

8Lehrman, Don and Blanchard, Charles. Memorandum: Independent BAMP Review and Assessment, T&B

Systems, 7 October 1998.
112

Greater than 90% of the total SO2 emissions for the 100 km region are located onshore in the

northeast to northwest quadrant.

BAMP PREFERRED OPTION

Table 1 C.5 describes the second option and the rational for the location, the equipment, and data to

be collected, along with a justification for the data collected.

The preferred option contains four sites for collection of continuous aloft meteorological data,

including temperature, wind speed and wind direction at different heights. This information is

necessary to describe the flow from onshore areas towards the BNWA and also to provide

information on how transported emissions can be mixed down to the surface under the high S02

regimes which occur during the winter. Three of the sites, those at Breton Island, southwest of

Pascagoula in the OCS, and northwest of Breton Island would capture the dominant winter time

flow, which is of most interest, as well as flow for other seasons. The latter site would also give

information the land-water interface. The last site, at South West Pass, is important in that cold water

from the Mississippi forms a cold water pool at the mouth of the Mississippi surrounded by the

warmer Gulf water. Air above this cold water pool cools and sinks with resultant mixing. This

mixing provides one way for emissions over the warmer Gulf waters to be brought to the surface and

potentially impact the BNWA under certain flow regimes, and needs to be documented. This

phenomenon occurs during high S02 concentrations.9 All this information would be used either for

input or evaluation of whatever meteorological model is used in subsequent modeling.

The surface sites would provide, for the most part, surface wind speed, direction, temperature,

relative humidity an and ambient 502 measurements. Those surface sitesmainly buoyslocated

in water would also provide sea surface temperature. These too, are necessary for whatever

meteorological model would be used in subsequent modeling, either for input or for model

evaluation. Similarly, the ambient measurements would be used for model evaluation.

All of the data would also be available for a more refined set of analyses that should lead to

significant improvement in the conceptual model for describing the high SO2 episodes.

A more complete description of the network design is Task 3 report, Design of the Breton

Aerometric Monitoring Program.

BRETON NTL ALTERNATIVE NETWORK

As noted above, it appears that there are insufficient funds to implement the BAMP Preferred

Option. Because the Breton NTL required development of a meteorological network to assess the

impacts of OCS sources on the BNWA, an alternative network design was devised with input from

9Roberts, Nash C, Jr., Memorandum: Local Influences of the Winter Cold Water Pool at the Mouth of the

Mississippi River, 15 April 1998.
Table 1C.5. BAMP preferred option.

113

LOCATION

LOCATION

JUSTIFICATION EQUIPMENT

MONITORED

PARAMETERS

EQUIPMENT

JUSTIFICATION

Breton Island Within BNWA; Critical

for dispersion modeling

input

- 30- meter tower

- Radar profiler

- RASS

- Air Quality

analyzers

- WS, WD, temp,

turbulence data at 2

levels

- Multi-level wind data

- Multi-level

temperature data

- SO2, NO2

- Lower level met data

to provide complete

profile in the BNWA

- Wind data for model

input

- Upper air

temperature and

mixing layer data

- Air quality impact

assessment within

theBNWA

NW of Breton

Island

Change from land to

water-based influence

- 10-meter met

station

- Radar profiler

- RASS

- WS, WD, Temp at

10-meters

- Multi-level wind data

- Multi-level

temperature data

- Lower level met data

- Wind data for model

input

- Upper air

temperature and

mixing layer data

East of Main

Pass in OCS

Surface met data gap

over water

- Buoy - WS; WD; water,

ambient air, and dewpt temps; pressure;

visibility; and wave

ht. data

- Over water surface

met data for model

input

SW Pass in

OCS

Key area for

Mississippi River and

Gulf water mixing

- Existing C-Man

station

- Radar profiler

- WS; WD; water,

ambient air, and

dew-pt temps;

pressure; visibility;

and wave ht. data

- Multi-level wind data

- Existing over water

data

- Wind data for model

input

Boothville, LA Assess impacts from

offshore emission

sources to the S and

SW

- Air quality

analyzer

- 10-meter met

station

- SO2

- WS, WD, Temp at

10-meters

- SO2 impact

assessment

- Real-time con-csponding met data

for air quality

measure- ments

Cat Island, MS

(or closer to the

northern end of

the BNWA)

Assess impacts from

onshore emission

sources to the N and

offshore sources to the

SE and S

- Air quality

analyzer

- 10-meter met

station

- SO2

- WS, WD, Temp at

I 0-meters

- SO2 impact

assessment - Real-time corresponding met data

for air quality

measurements
114

Table 1 C .5. (continued)

MMS regional meteorologists. This network is limited in scope and does not emphasize the transport

from the onshore areas that represent the majority of SO2 emissions within the 100-kilometer radius

of the BNWA. The network builds upon the information that was gained in the BAMP Phase I effort,

and is shown in Table 1C.6.

The equipment and equipment justification are not given on this table, but are the same as in Table

1 C.5 for the corresponding equipment/justification. The locations for sites are similar or the same

in most cases, but there is increased emphasis on delineating flow patterns associated with OCS

sources (sites at the mouth of the Mississippi and the eastern portion of the Central Planning Area),

rather than onshore sources. In addition, the air quality monitoring network would collect both

hourly SO2 and NOx ambient concentration data. This additional air quality information would be

useful for preparation of Environmental Impact Statement for new lease sales in the Central Planning

Area, as well as for the air quality portions of Environmental Assessments for OCS sources. While

the data collected under this alternative can be used for modeling, it is not sufficient for a rigorous

evaluation of any of the modeling systems identified in the BAMP Phase I work.

SUMMARY

The BAMP study was undertaken to provide information upon which to design an aerometric data

collection network for the Breton National Wildlife Area (BNWA). The objective was to secure data

to enhance the understanding of the causes of high 502 concentrations at the BNWA, and toprovide

data for air quality model evaluation. The resultant proposed network is intended to better define

Dauphin Island,

AL

Assess impacts from

onshore emission

sources to the N and

offshore sources to the

S and SW

Air quality

analyzer

- Existing C-Man

Station

- SO2

- WS; WD; water,

ambient air, and

dew-pt temps;

pressure; visibility;

and wave ht. data

- SO2 impact

assessment - Real-time corresponding met data

for air quality

measure- ments

East of

Chandeleur

Islands in the

OCS

Surface met and water

data supplement

- Buoy - WS; WD; water,

ambient air, and

dew-pt temps;

pressure; visibility;

and wave ht. data

- Data for model input

South of Mobile

and East of

Breton Island in

the OCS

Surface met and water

data supplement

- Buoy - WS; WD; water,

ambient air, and

dew-pt temps;

pressure; visibility;

and wave ht. data

- Data for model input

South of

Pascagoula, MS

in the OCS

Northern end of the

study area in an over

water environment

- Radar profiler - Multi-level wind data - Over water wind

profile data for

model input
Table 1 C.6. Breton NTL alternative.

115

transport of emissions from onshore sources to the BNWA, as the highest S02 concentrations occur

during the winter time when flow is from the northwest to northeast. While the proposed network

can be used for modeling, it will not be sufficient for a rigorous evaluation of different models.

A second network, more limited in scope, is also described. This alternative network would satisfy

the data collection requirements in the Breton Notice to Lessees, and focus on offshore sources.

LOCATION MONITORED PARAMETERS JUSTIFICATION

Breton Island, LA - Surface met

- Doppler SODAR

- RASS-NQISO

- Characterize conditions over the

islands

Mouth of Mississippi River - Surface met - Doppler SODAR

RASS- NOX/SOX

Most likely to experience stable

atmosphere. Wind shift across

Delta.

Dauphin Island, AL - Existing surface meteorologyNON/SQ,

Eastern portion of Central Planning

Area

- Surface met - Strong sea surface temp.

gradients in winter, Wind shift

across Delta

Eastern portion of Central Planning

Area

- Surface met- Radar profilerRASS

- Upwind location thru which

pollutants have transported.

Strong sea surface temp gradient

in winter

Southeast of mouth of Mississippi

River

- C-Man Buoy including surface

met and sea surface temperature

- Strong sea surface temp. gradient

in winter. Wind shift across

Delta
116

BOUNDARY LAYER STUDY IN THE WESTERN AND

CENTRAL GULF OF MEXICO

Dr. Paul T. Roberts

Mr. Timothy S. Dye

Sonoma Technology, Inc.

Dr. Steven R. Hanna

Consulting Meteorologist

This four-year project is just beginning. This paper summarizes the plan for the project; updates on

the project will occur at future ITM meetings.

PROJECT OBJECT IVES

The purpose of this study is to provide the MMS with a description and analysis of the atmospheric

boundary layer and how its structure influences the dispersion and transport of pollutants in the

western and central Gulf of Mexico. MMS will use the results of this study to support techniques for

evaluating the effects of oil and gas exploration, development, and production activities in the Outer

Continental Shelf (OCS) on air quality over coastal areas. Specific activities will include the

following:

Initiate the study and perform detailed planning for the study.

Collect data into a common database.

Perform characterization and analysis of the atmospheric boundary-layer structure.

Prepare synthesis reports and a database.

To complete this study we will conduct a number of technical tasks including:

Produce a data inventory for synthesizing the characteristics of the Atmospheric Boundary

Layer (ABL) and its dispersion properties in the western and central Gulf of Mexico, based

on 1998 to 2001 observations and modeling results.

Evaluate annual, seasonal, and diurnal variations in the ABL's structure.

Describe the processes governing variations in the ABL's structure.

Evaluate transport and mixing characteristics that govern pollutant dispersion over diurnal

and multi-day scales.

Provide conceptual model summary of processes that influence the ABL's structure and

variability and pollutant transport and dispersion.
KEY TECHNICAL IS SUES

A complete and quality-assured data set. If the data set is incomplete, or if individual values

are in error, then the analysis results obtained using the data set might be in error, or more

uncertain than otherwise.

Data that is quality assured at Level 1 (consistent with physical constraints and other

measurements at the same site by the same monitor).

Data that is quality assured at Level 2 (consistent with measurements collected at other sites,

and with other methods).

Data representativeness (of the ABL, of the region where the data were collected, of the

important ABL processes).

Control of data management activities.

Database accessibility (ease of access to quality-controlled data, to statistical summaries of

the data, and to derived ABL parameters).

How to use data to characterize ABL.

Understanding of ABL processes, especially over water and coastal areas.

Understanding of transport and dispersion processes, including the uses and limitations of

models

There has always been great uncertainty concerning the vertical and horizontal variability of the

atmospheric boundary layer in the Gulf of Mexico. For example, the depth of the boundary layer and

its vertical stability and wind and turbulence structure can vary greatly in OCS zones due to

horizontal variations in sea surface temperature and the overlying air mass. We are fortunate that the

MMS now has available the following new boundary layer observations in the Gulf of Mexico - two

meteorological stations collecting observations of the atmospheric boundary layer for three years

(1998-2001) by using 915 MHz radar profilers, 2 KHz Radio Acoustic Sounding Systems (RAS 5),

and surface meteorology units. The profilers will measure winds and virtual temperatures between

the surface and heights of a few kilometers, and the surface stations will measure sea surface

temperature as well as wind speed, wind direction, air temperature, and mixing ratio.

The two most important meteorological parameters for use in transport and dispersion models are

wind velocity and vertical stability. These parameters are needed over the full depth of the overwater

boundary layer (i.e., up to heights of 1 or 2 kilometers), to better account for variations in transport

speed, transport direction, turbulent dispersion, and stability over the depth of the pollutant plume.

Over travel times of several hours to a few days, or travel distances of several kilometers to a few

hundred kilometers, such pollutant plumes can disperse upwards to the top of the boundary layer,

can shear off in several directions, and can be subjected to layering during the transition and

nighttime hours. The previous practice of using estimates of stability based on the difference between

sea surface and air temperature, and single wind speed observations was often unsatisfactory.

The new data will be analyzed to investigate the following technical issues:

The overwater surface energy balance will be studied using the near-surface observations for

both steady-state horizontally-homogeneous conditions and for conditions variable in time

117
118

and space. A climatology of latent heat versus sensible heat fluxes will be developed for both

situations, and parameterizations should be developed for use in situations when only

degraded data are available.

Given the surface energy balance components, the vertical profiles of wind and temperature

will be studied to develop climatologies and parameterizations. In particular, it is desirable

to be able to estimate the full vertical profiles of wind and temperature based only on nearsurface measurements of air-water temperature differences and wind speeds.

The extensive vertical temperature profiles could be studied to estimate the mixing depths

and prepare empirical formulas to parameterize these observations.

The frequency of occurrence of very stable conditions near the surface and in layers aloft

could be investigated due to the importance of these layers for defining worst-case conditions

for the dispersion of air pollutants.

The horizontal spatial variability of wind speed and direction could be studied to identify the

fraction of time that wind directions and speeds persist over several hours in the Gulf of

Mexico, thus causing direct straight-line transport of pollutants toward receptors on the

shoreline.

Vertical profiles of wind and temperature in the near-surface layer (i.e., heights below about

50 m) could be plotted and analyzed to derive surface roughness length relations and to

estimate the scaling velocity (u*) and scaling temperature (T*). These scaling parameters are

directly related to surface momentum and heat fluxes. Since turbulent velocities (important

to dispersion) are directly proportional to u, it should be possible to derive improved

parameterizations for the dispersion coefficients and o. Perhaps the single most important

technical issue for understanding over-water air quality dispersion is the ability to properly

assess the mixing depth.

Using the data collected by the radar wind profilers, hourly mixing depth estimates can be estimated

from a combination of the refractive index structure parameter (C2), RASS virtual temperature

profiles, and surface measurements. Radar profiler mixing depth estimates have been demonstrated

to relate well to other fundamental mixing depth estimation techniques using rawinsonde

temperature profiles and aircraft data.

Estimating hourly mixing depths from profiler/RASS data is relatively straightforward. Using a

technique developed by STI, we will estimate mixing depths from the profiler's reflectivity

measurements and RAS S's virtual temperature profiles. The refractive index structure parameter

(C2) is computed from the profiler's reflectivity measurements. Maximum values of C2 have been

theoretically and observationally linked to the top of the mixed layer. RASS virtual temperature

profiles coupled with surface virtual temperature measurements can estimate the height of the mixed

layer by using stability analysis.

Conceptual Model Development

We will develop a conceptual model of ABL characteristics and variability (as part of Task 3) and

of pollutant transport and dispersion (as part of Task 4) in the offshore and coastal environment of

the western and central Gulf of Mexico. The conceptual model will describe and illustrate the major

meteorological phenomena which control the ABL structure and variability (Task 3) and which
119

control pollutant transport and dispersion (Task 4). The purpose of developing a conceptual model

is to summarize the current state of knowledge, to provide a basis for testing and evaluating specific

hypotheses, to focus continuing analysis efforts on the most important issues, and to identify those

processes which must be represented in models.

Note the following regarding conceptual models:

The controlling processes may differ spatially, and by month, season, and weather pattern.

The scale of controlling processes vary from synoptic to local.

The type of controlling processes include synoptic, geographic (e.g., coastline), and thermal.

Example processes to be considered for inclusion in a conceptual model include the following:

Synoptic weather patterns, including fronts and highllow pressure systems.

High-pressure induced subsidence (warming).

Air mass advection.

Thermal oceanlatmospheric interactions.

Land/sea breeze processes (especially for distinct shorelines).

Diffuse shoreline in central Louisiana.

The following sections provide summary information on the technical tasks.

TASK 1 STUDY INITIATION

Establish a Scientific Review Board (SRB). The SRB members will inspect the progress and

the scientific validity of the study and its deliverables, including reviewing the study plan,

interim synthesis report, and final synthesis report.

Prepare and distribute a draft study plan summarizing how we will perform the study tasks

and meet the study objectives, review the study plan, and revise the study plan based on

comments received.

TASK 2 DATA COLLECTION AND INVENTORY

Database

A Microsoft Access database will be used to archive the data for this project.

The database will allow output of data into several different types of formats, including

ASCII, comma-separated-value (CSV), and space-delimited, which are capable of being

imported into other programs (e.g., ARC/INFO, Excel).

The database will store:

Metadata: to describe the content, quality, condition, and other characteristics

of data that help users locate and understand the data. - Observations and calculated fields: measurements from surface and upper-air

sensors, as well as calculated fields generated as part of Task 3.
120

Three-dimensional fields: contain a reference to the model analysis fields.

Storing the actual model output in an Access database is inefficient due to the

large amount of data; however, the database will manage the inventory for the

model output fields.

To efficiently monitor and track the contents of the database, automated reporting will be

used to generate data availability and data validation levels reports.

Graphical user interface (GUI) will allow for quick and efficient display and analysis of the

database. Several display types are available: - Time-series

- Spatial plots

- Statistical surnrnaiy

- Trajectory plots

- Cross section plot - Output options will allow the users to save displays as files, graphics, or

animations.

Creation of the database will be done on a routine basis (e.g., every quarter). Prior to entry

into the database, data will undergo format conversion; standardization of the units, time

zones, and time conventions; and Level 1 and Level 2 data validation.

TASK 3 ANALYSIS OF THE ABL STRUCTURE

Objectives

Characterize the ABL

Evaluate annual, seasonal, and diurnal variations in ABL structure

Describe processes that influence ABL structure and variations

Approach

Describe ABL using measurements

Describe ABL using vertically averaged variables and bulk theory

Perform statistical and time-series analyses

Perform correlations and propose simple relationships using only surface observations

* Describe processes

Issues

Similarities Between Overland and Overwater Boundary Layers

The basic boundary layer theories and equations apply over any surface, as long as

you are careful about the definitions (i.e., the heat flux used in calculating L must

include the effects of the latent heat flux).

Mesoscale eddies, with time scales from a minute to an hour, are present over both

land and water, and are not observed to diminish even over the open ocean.
It is possible to parameterize the entire boundary layer based on simple observations

of wind speed near the surface, air-water temperature differences, and relative

humidity.

There is no substitute for observations through the entire depth of the boundary layer,

because elevated inversion layers or shear layers can unexpectedly occur.

Differences Between Overwater and Overland Boundary Layers

Roughness length, z0, is a strong function of wind speed over water.

Because of the high thermal conductivity of water and the mixing in the boundary

layer of the water, the water surface temperature only slowly reacts to changes in air

temperature. As a result, the stability over water does not follow the typical diurnal

cycle characteristic of land. In fact, it can be stable in the day and unstable at night,

or it can be stable or unstable for weeks at a time.

The only time strong stability (positive or negative) can occur over water is if there

is advection of a warm air mass over cold water or a cold air mass over warm water.

Most of the time, the latent heat flux over water is larger than the sensible heat flux.

It is essential that the vertical gradient of water vapor be included along with the

vertical gradient of temperature in the calculation of any stability parameter such as

the Monin-Obukhov length. It is possible to have a temperature inversion and still

have unstable conditions, due to a decrease of specific humidity with height.

Plusses and Minuses of Available Data

Plusses: 1. Continuous records over three years from two MMS profiler stations, with

wind and temperature data (at about 1 OOrn resolution) extending from 150 m

to about 4 km.

Near-surface data from platforms and buoys over the three-year

period.

Archived ETA NWP mode outputs available for the same time

period.

Many on-shore data also available.

Minuses: 1. No fast response flux data (e.g., <w'T'>)

Wind and temperature measurement at only one height in the lowest

100 m.

Insufficient coverage to resolve sealland breezes, TIBLs, and other

local phenomena.

We identified 10 different synoptic weather patterns that influence large-scale flows in the

northeastern Gulf (STI work for the NE Gulf Meteorological Study, ongoing, report due out later in

1998). Once several of these patterns are slightly modified to focus on the western and central Gulf,

these patterns can be used to classify days during the study period (June 1998 through May 2001).

The frequency of these patterns will vary by season. Several of these synoptic classifications show

features which dominate winds and transport patterns in the area of interest. Other patterns show

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122

more neutral gradients in the offshore and coastal areas of interest, and thus local characteristics

would likely dominate flows and transport. The synoptic features also likely influence stability in

the regions, and thus strongly influence mixing heights and dispersion characteristics. As part of this

task, we will modify the classifications for the western and central Gulf of Mexico, and will classify

every day in the three year period; these classifications will be used in other analyses in both Tasks

3 and 4.

TASK 4 DISPERSION ANALYSIS

Objectives

Characterize the dispersion properties of the ABL.

Evaluate transport and mixing characteristics of ABL that govern pollutant dispersion.

Include diurnal and multi-day scales.

Describe processes that influence ABL transport and dispersion.

Overall Technical Approach

Describe transport and mixing fields using statistical analyses.

Describe processes that influence transport and mixing (conceptual model).

Identify limitations of using homogeneous and equilibrium conditions.

Recommend improvements to models & observations.

Technical Details of Approach

Compare observed transport winds with Eta winds. This will occur at location and times

when both the observed and Eta winds exist. If differences occur, then we will look into the

potential causes.

Select periods of interest, ensuring representation from various seasons and met

classifications (about 1 monthlseason).

Generate wind and mixing height fields with diagnostic model (we will likely use CALMET,

but we will evaluate various alternatives before proceeding).

Perform statistical analysis (e.g. averages, perturbations, and cycles) of transport wind,

mixing height, and vertical diffusivity fields.

Separate the results into several regions, such as offshore, near shore, coastal, &and onshore.

Summarize statistical results and perform a few case studies to investigate similarities and

differences among seasons and classifications.

ID controlling processes by weather classification and season.

Perform detailed analysis for selected cases.

Illustrate controlling processes with examples.

One of the goals of this project is to develop a conceptual model of pollutant transport and dispersion

in the offshore and coastal environment of the western and central Gulf of Mexico. The conceptual

model will describe and illustrate the major meteorological phenomena which control pollutant

transport and dispersion. The purpose of developing a conceptual model is to summarize the current
igure 1C.lO. Project schedule for Boundary Layer Study in the Western and Central Gulf of Mexico. TavkNume 1999 2000 2001 

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124

state of knowledge, to provide a basis for testing and evaluating specific hypotheses, to focus

continuing analysis efforts on the most important issues, and to identify those processes which must

be represented in models.

A schedule for the project is shown in Figure 1C.1O.

Dr. Paul T. Roberts, STI Vice President, designs and manages air quality field, data management,

and data analysis projects. Most of these projects have involved the use of field data and analysis

methods to understand important meteorological and air quality phenomena, and to develop, apply,

and evaluate meteorological and photochemical model. Specific projects during which boundarylayer processes over water and shoreline environments were important components include the

MMS-sponsored Gulf of Mexico Air Quality Study (southeast Texas and Louisiana and offshore),

the Southern California Air Quality Study (SCAQS) and several subsequent data analysis efforts in

and around the South Coast Air Basin (SoCAB), the Lake Michigan Ozone Study, and the

NARSTO-Northeast Air Quality Study (covering Virginia to Maine, including offshore).

Mr. Timothy S. Dye, STI' s Manager of Meteorological Programs, has operated, quality controlled,

and analyzed radar wind profiler wind and temperature data for over 11 years. Mr. Dye has

extensively used these upper-air data to conduct analyses of pollutant formation, transport, and

dispersion. He developed algorithms to estimate mixing height from radar profiler reflectivity and

temperature data and has used this technique to understand marine and overland boundary layer

structure and evolution in such programs as the Lake Michigan Ozone Study, the Gulf of Mexico

Air Quality Study, and the NARSTO-Northeast Air Quality Study. Mr. Dye is co-author of the new

EPA guidelines for collecting, quality controlling, and managing the upper-air data from radar

proffler/RASS, sodar, and rawinsonde systems and has designed several methods for conducting

Level 2 data validation of upper-air data.

Dr. Steven R. Hanna is a specialist in atmospheric turbulence and dispersion, in the analysis of

meteorological and aerometric data, and in the development, evaluation, and application of air

quality models. He is an AMS Certified Consulting Meteorologist with over 30 years of experience.

He has led several research and development projects involving, for example, the statistical

evaluations of hazardous gas dispersion models and regional ozone models; the development of

models for the dispersion of emissions from tall power plant stacks and from offshore oil platforms;

and the analysis of data from large regional field experiments in the Santa Barbara area, in the Lake

Michigan region, in the Gulf of Mexico, and in the northeastern United States. He led the

development of the OCD Model. From 1988-1997, Dr. Hanna was Chief Editor of the Journal of

Applied Meteorology, and has published over 100 articles in peer-reviewed journals, six chapters in

books, and four books in which he is the primary author.
Introduction

Investigations of Live/Hard-Bottom Areas

Offshore Florida and Louisiana

Monitoring Archaeological Sites

Biological Characterization and Monitoring

of Sonniej- Bank

The Monitoring and Analysis of Operations

Sites Forregulatory Compliance

SESSION 2A

SEA FLOOR MONITORING

Co-Chairs: Dr. Jack B. Irion and Dr. Richard J. Anuskiewicz

Date: December 8, 1998

Presentation Author/Affiliation

Dr. Jack Irion

Minerals Management Service

Gulf of Mexico OCS Region

Dr. Richard J. Anuskjewjcz

Minerals Management Service

Gulf of Mexico OCS Region

Dr. Jack B. Irion

Minerals Management Service

Gulf of Mexico OCS Region

Gregory S. Boland

Minerals Management Service

Gulf of Mexico OCS Region

Mr. Les Dauterive

Minerals Management Service

Gulf of Mexico OCS Region

125
INTRODUCTION

Dr. Jack B. Irion

Minerals Management Service

Gulf of Mexico OCS Region

The MMS Seafloor Monitoring Program initially began in 1996 as a means to determine if the oil and gas industry was doing all they should to avoid impact to a protected group of biological features off the coast of Mississippi and Alabama. These features consist of carbonate pinnacles clustered along the shelf break that formed as coral reefs during the last Ice Age. Today, these pinnacles are under 300 feet of water and are an important habitat for red snapper and other game fish. This area of 70 lease blocks is collectively known as the Pinnacle Trend and is protected by MMS stipulation. Industry is required to locate these features using remote sensing surveys and to avoid then during pipeline construction, drilling operations, and platform installation. However, since the pinnacles lay out of sight beneath the sea, we, as an agency, had no real way of knowing if industry was carrying out their responsibility to avoid harming them.. It became necessary, then, to develop a means to monitor industry performance and the effectiveness ofMMS mitigations applied to permit applications.

Regulations for implementing the procedural provisions of the National Environmental PolicyAct (40 CFR 1505.2) state that a monitoring and enforcement program shall be adopted and summarized where applicable for any mitigation." The MMS, in order to ensure safety and environmental protection, also has the authority under 30 CFR 250.33 (o) for Exploration Plans and 30 CFR 250.34 (s) for Development Plans to require Operators to conduct various monitoring programs. More specific guidance to operators has been and can be provided through Notice to Lessees (NTLs), Lettersto Lessees (LTLs), and Lease Sale Environmental Impact Statements (EISs). Presently, monitoring programs can be initiated through NTL 98-11 for chemosynthetic communities, NTL 9 8-26 for site clearance, the Live-Bottoms (Low Relief) stipulation, and the Live- Bottom (Pinnacle Trend) stipulation.

Several schemes were initially suggested to accomplish the initial goal of monitoring the seafloor in the pinnacle trend. These included using ROV cameras and hiring Contractors to survey a single block. Our Regional Supervisor for Leasing and Environment, however, supported an alternative, hands-on approach, that involved purchasing a side-scan sonar and positioning equipment and sending MMS scientists into the field. We believed that an in-house MMS monitoring team would give us more flexibility and control, allow us to respond rapidly to emergency issues, and keep costs down. Using the same budget originally allocated for a single survey in the Pinnacle Trend, monitoring team completed five the

separate projects in its first season in 1997 and looked at a variety of environmental and operations issues. When combined with the scientific dive team already in existence, MMS was given eyes to see what kind of job we were doing to protect the submarine environment.

127
128

As this project was being realized, added weight was given to the need for developing a monitoring

program by the Government Performance and Results Act of 1993, as amended in 1997. This act requires federal agencies to report on their performance in terms of measuring "outcomes" that result

from their activities, rather than outputs. More specifically, MMS is required to ask of itself how

effective the agency is in ensuring environmentally sound OCS operations. The seafloor monitoring

program became an important tool for managing for results and has been expanded beyond its original mandate to assess the Pinnacle Trendto include a sample of virtually all types ofmitigations affecting the seafloor.

The second field season of the seafloor monitoring program concluded in November of this year and was notable for achieving a number of successes despite an unusually active hurricane season. In

fact, only one proposed project was totally canceled, and this after suffering not one, but three

cancellations for weather. The background on this project, which continues monitoring efforts at

biologically diverse Sonnier Bank, and is now scheduled for next June.

By combining the technologies of side-scan sonar survey and SCUBA diving, MMS scientists are

able to directly study significant seafloorfeatures that come to light as a result of oil and gas industry

surveys. In this way, we are able to better apply appropriate mitigative requirements for their protection without being overly restrictive to industry. A good example of this is our assessment of

a newly discovered coral habitat off Louisiana. Dr. Rik Anuskiewicz summarizes this project as well of the results of an experiment conducted to compare the effectiveness of high resolution side-scan

over photo-documentation surveys in the eastern Gulf.

The seafloor monitoring program hasproven to be useful in assessing archaeological features as well

as biological ones. By surveying sunken vessels discovered during lease block or pipeline surveys with our high resolution equipment, we are frequently able to distinguish modern wrecks from

possibly historic ones. Six wrecks have been assessed in this way; five proved be modern and of no

particular significance. One wreck, discovered in 1998, may be historic and will be investigated by the dive team next year. In addition, the monitoring program has assessed several historic wrecks

as part of our responsibility for the management of historic wrecks on the outer continental shelf. By locating and identifying historic wrecks, we can reduce the number of blocks where industry is

required to search for them using remote sensing survey at 50-meter survey intervals. In this way, we have already eliminated more than 20 blocks from this requirement at an estimated savings to industry of more than a million dollars.

Having this equipment and expertise in-house, we are sometimes able to respond to requests for assistance from other organizations with shared interests. This past summer we were afforded the

opportunity to provide assistance to the University of West Florida's exploration for historic shipwrecks in Pensacola Bay. Using our high resolution side-scan we were able to provide UWF with acoustic images of an 18th century Spanish wreck off Santa Rosa Island, and the late 19th century sailing ship Catharine. Using our equipment, we were able to relocate and buoy the 439- year-old Emanuel Point wreck in time for a wreath-laying ceremony with the president of Spain to

conlnlernorate the establishment of Pensacola bi Tristan de Luna. This wreck is one of the original vessels that first brought colonists to Pensacola.
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Discovering shipwrecks and exploring coral reefs may seem like a glamorous job, but the seafloor

monitoring program also tackles critical operations issues as well. This year alone we have inspected

anchor damage from a break away derrick barge, found evidence of an abandoned drill site not

properly restored, and examined the site of an oil leak in the vicinity of an artificial reef

Dr. Jack B. Irion joined the Minerals Management Service in August 1995 with the title of marine

archaeologist. Prior to MMS, Dr. Irion served asvice president for Nautical Archaeological Services

with the consulting firm of R. Christopher Goodwin & Associates, Inc., in New Orleans, Louisiana.

For over 15 years, Dr. Irion provided archaeological consulting services to the Baltimore, Charleston,

Mobile, New Orleans, Pittsburgh, Philadelphia, Savannah, Vicksburg, and Wilmington Districts of

the Corps of Engineers, as well as to the Maryland Port Administration, and the State of Tennessee.

Dr. Irion received his B.A. (1974) and M.A. (1977) in Archaeological Studies from The University

of Texas at Austin. He was awarded his Ph.D. from the Institute of Latin American Studies of the

University of Texas in 1991. During his career, Dr. Irion has specialized in conducting remote

sensing surveys for shipwrecks, which succeeded in locating such historically significant vessels as

the C.S.S. Louisiana, the sailing barque Maxwell, and the steamboats Princess, and Kentucky. In

addition, he has directed numerous diving investigations on historic shipwrecks, including the

steamship Columbus and the Civil War gunboats Tawah and Key West. Most recently, he has

participated in MMS investigations of the Civil War vessel U.S.S. Hatteras and the steam packet

New York.

INVESTIGATIONS OF LIVE/HARD-BOTTOM AREAS

OFFSHORE FLORIDA AND LOUISIANA

Dr. Richard J. Anuskiewicz

Minerals Management Service

Gulf of Mexico OCS Region

INTRODUCTION

The following three field investigations are a part of the Gulf ofMexico Region (GOMR) Sea Floor

Monitoring Program. These investigations used high resolution side-scan sonar imagery and diver

hands-on verification of data to make recommendations about future projects with similar

informational needs. These three field projects represent and support new imagery methods to access

the presence, absence, and potential impact to hard/live-bottom biological communities living on the

sea floor of oil and gas development. Hard/live-bottom communities can be defined as "sea grass

communities or those areas which contain biological assemblages consisting of such sessile

invertebrates as sea fans, sea whips, hydroids, anemones, ascidians, sponges, bryozoans, or corals

living upon and attached to naturally occurring hard or rocky formations with rough, broken, or
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smooth topography; or areas whose lithotope favors the accumulation of turtles, fishes, and other

fauna (Bull 1998 )."

DESTN DOME 56 UNIT EXPORT PIPELINE ROUTE SURVEY

Background

The first field project utilized a dual efforts of high resolution side-scan imagery and MMS diver

evaluation to investigate the presence, absence, and potential impact to biological habitat of a

proposed Chevron export pipeline. Chevron's initial photo-documentation biological survey of the

proposed pipeline route identified one area of hardllive bottom communities. Chevron then

resurveyed a segment around the live-bottom area to find a new route that would not impact the

biological habitat. The focus of the MMS high resolution side-scan survey was to determine if

Chevron's new route would bypass and avoid patches of live-bottoms identified in the initial

Chevron survey (Dauterive 1998).

Field Methods

A sonar image of a patch of live bottom that was identified by the initial Chevron photodocumentation survey of the proposed pipeline linear route was captured as a reference image for

the side-scan survey of the pipeline reroute. The MIMS side-scan surveywas conducted using a highresolution, 300-kHz Marine Sonic Sonar set at a scanning range of 150 meters per scanning channel.

Next the MMS side-scan plotted positioning over the proposed reroute by using the Trimble

NT200D Differential Global Positioning System (DGPS) with real time position accuracy of± 5

meters. The sonar DGPS was interfaced with a laptop PC running the GPSNAV navigation program,

which provided steering guidance to the helmsman. An anomalous sea floor image was recorded

during the survey of the pipeline reroute. A marker buoy was deployed at this spot and the MMS

Scientific Dive Team conducted circle and linear search of the area.

Findings

Two teams of divers searched the area around the marker buoy and no identified live-bottom

features. The divers reported and described the sea floor as primarily a fine, white, sandy bottom

intertwined with large patches a darker brown sand. Initial MMS analysis of the color difference in

the sand suggests that the brown patches were like algae attached to larger grains of sand.

SEA FLOOR TOPOGRAPHIC HIGH IN WEST CAMERON AREA, REEF OR NO REEF

Background

An unusual topographic high was identified as a part of routine lease block shallow

hazard/archaeological report. This underwater feature trends almost northlsouth, is approximately

2,000 feet long, 100 foot wide near the center, and rises about 10 to 17 feet off the surroundingsea
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floor. The purpose of the MMS field investigation was to characterize the features's geologic

composition and evaluate the potential hard-bottom biological habitat. This characterization was

accomplished by examining seismic, sonar, and fathometeric remote-sensing survey data and

integrating these data with divers observations for the following geological reconstruction of this

feature.

Features Geology

Based on examination of seismic data, side-scan sonar, direct diver observation, and collected rock

samples, this geologic feature appears to be the "up thrown" side of a fault related to the dominant

salt diapir. The consolidated fine grain sandstone, siltstone, and mudstone is in well defined bedding

planes that define the base of the feature suggest sediment burial at depth and later uplift. The hard

calcareous material over this rock is due to subsequent reef building on the sea floor high. Seismic

evidence for this fault is obscured due to the attenuation of seismic wavelets by gas permeated

shallow sediments in the area (Dempre 1998).

The following biological information and discussion were taken from a trip report prepared by

biological oceanographer Greg Boland (J3oland 1998) for GOMR in August 1998.

Rock samples collected from the upper portion of the feature were examined by an MMS geologist,

and the feature was characterized geologically as a calcareous-like material that appeared to be

honeycombed with many open spaces and cavities. The texture was extremely rough and appeared

to be biogenic in origin. Diver visual observations of horizontal bedding planes arid fine grained

sediment under the carbonate cap suggest that the underlying formation is composed of sedimentary

rock (claystone or siltstone) that has been broken and uplifted, presumably by the nearby underlying

salt diapir. Divers' observations began away from the feature on soft bottom. Small outcrops of hard

substrate were first encountered at a depth of about 23.8 m as divers approached the feature.

Continuous and solid hard bottom was observed beyond the smaller outcrops at a depth of 22.9 m.

The rise in the bottom was abrupt but smooth and not a sharp edge or escarpment.

Near the center of the feature, or essentially the top of the ridge, numerous grooves or small fissures

in the substrate ran parallel the orientation of the feature, almost north-south. These grooves ran

continuously as far as the divers explored and probably represent expressions of sedimentary strata,

uplifted, tilted and exposed. The entire feature was below a distinct nepheloid layer, and underwater

visibility was estimated to be 10 m above the nepheloid layer and only 2 m at best on the feature

itself (i.e. the bottom).

Feature's Biology

Basic biological overview indicates that the dominant biological characteristic is a near 100% cover

of leafr algae. The algae was partially encrusted but also had a substantial branching component

forming bushy expressions over 60-70% of the substrate. Manyareas were 100% covered in algae,

and large patches were easily dislodged from their attachment to the bottom. A number of encrusting

invertebrates were also observed including sponges (bryozones and a few hard corals).
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Attached fauna was most prominently representated by numerous remnant parts of sea-whips, genus

Leptogorgia and Lophogorgia. The dead stalks were completely encrusted in sediment-laden algae

similar to the substrate in general. Approximately 95% of the sea-whips did not show any exposed

live tissue. A few hard scieractinian corals were observed including some occasional healthy

colonies of ivory bush coral, Oculina d[fusa. Some of the ivory bush corals were completely white

without symbiotic algae, and some were dark brown representing heavy colonization by symbiotic

algae. These corals ranged from a few cm to 6 cm. Two colonies of the reef-building coral

Siderastrea sp. were also seen and measured about 6 cm in diameter.

Other invertebrates observed included an olive shell and several small Murex (at least one was

alive). Several fire worms, Hermodice carunculata were seen, both on the substrate and on the stalks

of dead sea-whips. Inside depressions and small crevasses an occasional short-spined urchins

Echinometra sp. was observed.

Fisheriesby far, the dominant fish species observed (by biomass) was the red snapper. Many

hundreds of red snapper swam circles around the divers at all times, presumably in search for food.

Their length ranged from 20-30 cm.

Other fish species observed included:

One large jewfish, sound only

Several grey triggerfish

Numerous juvenile tomtate

Equal numbers of unidentified juvenile fish, possible vermillion snapper

Several Beaugregory damselfish

Several belted sand bass

Several slippery dick wrasses

One white spotted soapfish

One sheephead

One sandperch

One juvenile cubbyu

Also seen breathing above the reef structure was one large loggerhead turtle whose carapace length

was estimated to be about 75 cm.

Findings

Boland (1998) comments that it appears the ridge feature once supported a relatively diverse hardbottom community of invertebrates. However, due to unknown changes in the marine environment,

the common algae observed on this feature gained a substantial advantage over the other invertebrate

components. This dominant algae continued overgrowing and killing around 90% of the sea-whips,

as evidenced by their remaining skeletal stalks. Boland also suggests that a large percentage of other

encrusting forms such as bryozoans and sponges were also struggling to survive being overgrown

by the dominant algae.
133

At this time, it is difficult to predict whether the present condition at this reefwill continue and the

algae overgrowth will persist. However, this habitat represents a hard-bottom\live bottom system

characterized by a dominant single species of leafy algae. What also must be noted is at least one

species of hermatypic or reef-building coral is present; the reef can technically be represented or

called a "coral habitat." Boland further indicates that even the existence of oniy one coral colony

represents a narrowly defined set of environmental conditions rare for the surrounding area.

Therefore, the reef recently designated "RiknJack Reef' warrants environmental protection

equivalent to Sebree Bank off south Texas or similar hard-bottom areas of the Florida panhandle.

PHOTO-DOCUMENTATION SURVEYS VERSUS HIGH RESOLUTION SIDE-SCAN

Background

The GOMR presently requires operators and lessees, subject to the "Live-Bottom" stipulation in the

eastern Gulf of Mexico (EGOM), to conduct photo-documentation surveys as a part of a LiveBottom Report to be submitted to the MMS. GOMR prepared revised guidelines describing the

methodology to be employed on these surveys that became effective on 15 February 1989. Under

these guidelines, operators are given the option to either "clear" site specific areas or, alternatively,

their entire lease block. Site-specific surveys can be conducted in one of two ways. The most

commonly used method by the oil and gas industry is a radial pattern consisting of"12 transacts at

approximately 30 degrees to each other radiating from the drill site(s) out to at least 1,000 m."

Alternatively, surveys can be conducted along a grid pattern of 200 m spacing designed to "coincide

with the shape/configuration of each known or suspected hard or live-bottom area within 1,000 m

of the proposed drill site(s)." Lease-block surveys are to be conducted along parallel transacts spaced

200 m apart (Irion 1998).

Photo-Documentation Field Methods

Photo-documentation surveys are to consist of both "television" (videography) and color-still

photography. Typically, photo-documentation surveys use cameras (mounted in a large sled) that are

towed a few feet above the bottom from a vessel traveling about 3 knots. These surveys are complex

and costly. The towed equipment, including the mounting sled, weighs about 700 pounds and must

be deployed from a vessel at least 100 feet long equipped with a powerful lifting A-frame. None of

the photo-documentation contractors in the Gulf performing this service owns their own vessel, so

the equipment has to be installed in a contracted vessel generally an oil field supply-type boat. At

least a day is required to install the equipment and mobilize the vessel. This includes welding a large

hydraulic winch onto the deck, installing the complex electronic array into the boat, and testing and

troubleshooting equipment before departure.

Problems in Data Collection and Interpretation Using Photo-documentation

Despite the of effort required to conduct an optical survey of this nature, these surveys are limited

in their ability to locate and document hard-bottom features by two variables; 1.) the clarity of the

water and 2.) survey line spacing interval. In both the Destin Dome and Pensacola areas there is
134

normally present at the sea floor a nepheloid layer, which is a turbid zone of suspended sediment

particulates that can extend 3 to 6 m into the water column. The suspended particulates restrict

underwater visibility to about 3 m or less. As a result, the only part of the sea floor that is imaged

during a typical lease block survey is 25 survey line swaths about 3 m wide spaced 200 m apart. A

quick calculation of block area coverage indicates that only about 0.5% of the total surface area of

the block is photo-documented. Any hard-bottom areas that are less than 200 m wide and fall in

between the survey lines would go undetected.

Better Technology Produces Better Survey Data

Because of the insignificant sample size and apparently limited effectiveness of the photodocumentation survey, MMS and Chevron U.S.A., Inc. entered into a cooperative agreement to

explore the use of high resolution acoustic imaging (e.g. high resolution side-scan sonar) equipment

in lieu of standard optical imaging systems for live-bottom surveys in the eastern Gulf.

In August 1998 MMS marine scientists took part in a simultaneous photo-documentation and high

resolution sonar survey in Destin Dome Area, Block 1. On behalf of Chevron U.S.A., Inc.,

Continental Shelf Associates (CSA) was contracted to conduct a standard photo-documented survey.

The following is a short description on how a side-scan system works. Side-scan sonar transmits

sound waves to both sides of a towed sensor and measures the rate at which these waves reflect as

echoes off targets on the bottom. Unlike optical cameras, imaging systems that rely on the

propagation of sound under water are unaffected by water turbidity. The rate of reflection offobjects

of varying density is measured and processed by the instrument to producean image of the seafloor.1

The typical side-scan sonar used for lease block surveys in the Gulf of Mexico is a 100 kilohertz

(kHz) instrument. The system employed by MMS for this investigation utilizes a Marine Sonics 300

kHz tow-fish transducer. The higher frequency sonar produces a clearer image of the seafloor, which

makes it possible to distinguish details and sea floor textural changes not visible to the lower

resolution instrument. There is, however, a trade-off inrange, which is related to the physics of how

sound travels through water. A medium frequency 100 kHz system can image a survey swath of the

sea floor 600 m to either side of the towed sensor. The effective range of the 300 kHz system is

about 150 m to each side. If we were to use the standard photo-documentation line-spacinginterval

of 200 m, the 300 kHz side-scan can image 100% of the sea floor with 50% overlap. This would be

accomplished in the same amount of survey time required to sample only 0.5% of the sea floor using

the standard photo-documentation methodology (Irion 1998).

A question to ask when comparing these two sea floor scanning system is: "Can the side-scan really

'see' things the camera misses?" Based on our field work and observations the answer to that

question is "yes." As previously described, the towed camera array only "sees" what is directly

beneath it. The side-scan, on the other hand, can image objects up to a 150 m to either side of the

tow-fish. As a result, small, discreet hard-bottom areas that would be missed by the camera are easily

The faster the sound pulses (frequency), the greater are the number of waves that pass a point. Frequency is

measured in cycles (Or waves) per second. One cycle per second is called a Hertz (Hz).
135

distinguished in the side-scan record. Sonar images taken by MMS illustrate hard-bottom areas

detected by our side-scan survey in Destin Dome Block 1 that were not detected by GSA's photodocumentation survey. One image was a small, rocky outcrop measuring about 7.5 m by 4 m.

Although it is relatively small, the fact that it serves as a biological habitat is clear from the school

of fish that are seen clustered about it. High frequency sonar often shows marine fauna in the water

column. Another MMS sonar image was a larger patch of exposed, low-relief hard bottom rising less

than a meter off the sea floor and measuring approximately 1,500 m2 in area. Again, neither the small

outcrop nor the large, nearly football field-size patch of hard bottom were detected in the photodocumentation survey, or in an earlier hazards survey conducted by CSA using medium frequency

100 kHz sonar.

Since adverse weather conditions cut short MMS 's participation in the CSA survey, we re-scheduled

an independent investigation in September 1998 to collect additional images of hard-bottom features

off Florida. The first feature to be imaged was a significantly large ridge bisecting nearly the entire

block in Destin Dome Block 56. This feature, which rises some 5 m off the sea floor, was clearly

detected by the side-scan, which also provides an instant appreciation for its size and shape that the

camera would not. The second hard bottom imaged during this survey is a popular local dive spot,

known as Green's Hole," located just a few miles from Pensacola Bay. This feature consists of two

rocky outcrops occupying an area of approximately 780 m2 that support a rich diversity of marine

organisms. Because of its relatively small area, a feature such as Green's Hole likely would not have

been detected by photo-documentation survey alone.

Findings

Based on our observations, we believe that high-frequency side-scan sonar (300 kHz or greater)

offers a means of locating and documenting the extent of hard-bottom areas in the eastern Gulf of

Mexico that is superior to those photo-documentation surveys presently required by MMS. Side-scan

will likely not, however, detect such live-bottom areas as algal mats. However, these features are

transitory and non-permanent, and according to our marine biologists, impacts to them would likely

be short-term and reversible. What we believe to be one minor shortcoming is more than mitigated

by many major advantages. For example, using the presently required survey-line spacing of 200 m,

100 percent of sea floor can be imaged acoustically as opposed to only about 0.5 percent using

optical systems only. In addition, high-resolution sonar can distinguish subtle textural changes in the

sea floor and low-relief features that 100 kHz systems set on the maximum range scale will not.

Furthermore, most geophysical survey companies operating in the Gulf presently employ either Klein

or EdgeTech (EG&G) sonars with dual-frequency 100/500 kHz transducers. By a simple flip of a

switch, the same units that are presently used in the 100 kHz mode for hazards surveys can be

operated in a high-resolution 500 kHz mode. Finally, by requiring a slightly tighter line spacing (e.g.

200 m as opposed to 300 m) for the hazards surveys in the EGOM, hard-bottom areas could be

accurately mapped during this stage of data gathering rather than requiring a second, costly survey.
136

REFERENCES

Boland, Greg. 1998. Biological features RiknJac Ridge" reconnaissance from R'V Marie Hall. Trip

report prepared for Minerals Management Service, Gulf of Mexico Region internal Document.

New Orleans.

Bull, Ann. 1998. Personal communication.

Dauterive, Lester. 1998. Dive plan and trip report for Chevron's Dentin Dome 56 Unit export

pipeline. Minerals Management Service, Gulf of Mexico Internal Document. New Orleans.

Dempre, Terry. 1998. Personal communication.

Irion, Jack B. 1998. Trip report for an evaluation of the use of high resolution side-scan sonar to

replace photo-documentation surveys in the Eastern Gulf of Mexico. Minerals Management

Service, Gulf of Mexico Region Internal Document. New Orleans.

Rik Anuskiewicz was awarded his B.A. in 1972 and his M.A. in 1974 in anthropology, with

specialization is archaeology from California State University at Hayward. Rik was employed with

the U.S. Anny Corps of Engineer Districts of San Francisco, Savannah, and New England Division

from 1974 to 1984, as a terrestrial and underwater archaeologist. In 1980 he began work on his

doctorate. In 1984 he accepted his present position with Department of the Interior, Minerals

Management Service, Gulf of Mexico Region as a marine archaeologist. P1k received his Ph.D. in

1989 in anthropology, with specialization in marine remote-sensing and archaeology from the

University of Tennessee at Knoxville. P1k' s current research interest is focused on using remotesensing instrumentation as a tool for middle-range theory building through the correlation of

instrumental signatures to specific observable archaeological indices.

MONITORING ARCHAEOLOGICAL SITES

Dr. Jack B. Irion

Minerals Management Service

Gulf of Mexico OCS Region

Archaeological sites are among the resources on the Outer Continental Shelf (OCS) that are managed

by MMS. These seafloor features generally are reported to MMS as potentia1" sites by the oil and

gas industry after they conduct remote-sensing surveys within their lease blocks. Potential sites may

relate to either possible historic shipwrecks or prehistoric sites dating to the last Ice Age when sea

level was lower than it is today. Possible shipwreck sites include areas either where anomalous
137

readings of ferrous metals were detected or where the side-scan sonar image shows some unusual

bottom feature that resembles a vessel hull or shipwreck debris. Possible prehistoric sites are

identified in the subbottom record as relict landfomis where early man was likely to have camped,

such as channel margins, river terraces, levees, and point bars. Itis generally impossible to establish

from the remote-sensing records alone if any of these "potential" sites are, in fact, historic or

prehistoric sites.

Lacking this vital information, MMS establishes zones of protection around the potential sites

identified in the remote-sensing record and directs industry to avoid these features during its

operations. By performing monitoring surveys to verify that industry complied with these permit

requirements, MMS also has been able to determine whether many of these "potential" shipwreck

sites are actual historic sites worthy of federal protection. In most instances, these sites have been

found to be modem and can be dismissed as mere hazards. However, anumber of significant historic

sites have been located and documented on the federal OCS in the Gulf of Mexico as a result of

cooperation between industry, the MMS, and private citizens. This paper discusses some of the

significant sites that have been discovered on the OCS and their importance to the history of the Gulf

of Mexico. These sites include a steamship that was one of the first links of trade with a fledgling

Republic of Texas, the Civil War wreck of the USS Hatteras, a vessel we believe may have been

built as a Civil War blockade Runner, and numerous casualties of the German submarineWolf Packs

during World War II.

THE STEAMSHIP NEW YORK

History of the Vessel

The New York was constructed in New York City in 1837 for the Southern Steam Packet Company,

a partnership formed between J. P. Allaire, Charles Morgan, and John Haggerty. Vessel Registration

No. 340 (National Archives), dated 13 October 1843, identifies the vessel as a steamboat 165 feet

long, with a beam of 22 feet, and a depth of 10 feet. It was described as having one deck and two

masts. A drawing of the ship on file in the Mariner's Museum in Newport News, Virginia, shows

a cross-head type steam engine (Figure 2A.1).

During 1837 and 1838, the New York made regular trips between New York and Charleston, South

Carolina (Heyl 1969,225). After the Southern Steam Packet Company was dissolved, the vessel was

taken over by Morgan and transferred to New Orleans, where it was engaged in trade between that

city and Galveston, in the newly independent Republic of Texas. Her first voyage under Morgan was

undertaken November 1838, under consignment to McKixmey & Williams, agents (Hayes 1971,

323). Fierce competition soon broke up Morgan's monopoly on the Galveston-New Orleans trade,

and he responded by extending the New York's route to include New York City. In May 1839, the

New York undertook the first regular steamship service between Galveston and the Port of New

York, with stops at Key West and Charleston. The ship was advertised to make the voyage in eight

days and had accommodations for 200 passengers. The cabin rate between Galveston and New York

was $110.00 (Hayes 1971, 326).
138

Figure 2A. 1. Drawing of the steamship New York. Courtesy Mariners' Museum, Newport News,

Virginia.

The New York departed Galveston for what was to become her final voyage on 5 September 1846.

By 10 p.m. that evening, she came to anchor in heavy seas some 50 miles eastward of Galveston,

having unknowingly sailed into the path of a hurricane. After a fearsome pounding by seas and wind,

which lifted the promenade deck, stove in the starboard guard and wheel house, carried away the

smoke stack, and sprang the hull, the New York foundered in 10 fathoms of water at 6 a.m. on the

morning of September 7 (Daily Picayune, 10 September 1846). Seventeen passengers and crewmen,

including five children, were lost when the ship went down. The remaining survivors clung to rafts

fashioned from a portion of the promenade deck and other wreckage for more than 12 hours until

they were rescued by another steamer, the Galveston (New Orleans Gazette, 10 September 1846).

Discovery of the Wreck

A group of amateur divers from New Iberia, Louisiana, began searching for the wreck of the New

York in 1985. Working only from the sparse clues contained within the survivors' accounts published

in the New Orleans newspapers in 1846, the divers deduced the general location of the wreck site.

They subsequently interviewed shrimpers who worked in the area to obtain information on the
139

location of net hangs.1 Over the course of the next five years, the team systematically tested each

hang site in a ten-mile square area using a fish finder to locate targets above the seafloor. After a

supreme amount of effort and patience, utilizing equipment that is primitive by hydrographic

surveying standards, the divers discovered in 1990 a wreck they believed to be that of the New York.

Materials recovered from the site, including coins and amortising machine patented in 1836, were

consistent with the 1846 sinking of the steamer. Subsequent examination of the site by MMS

confirmed the presence of a low pressure steam engine at the site, which also is consistent with the

cross-head engine mounted in the New York (Figure 2A.2).

MMS Involvement with the New York

The High Island Area lease block in which the New York lies was surveyed by an oil and gas

company for shallow hazards in 1988 at a line spacing of 150 meters, the survey interval required

by MMS at the time for all blocks in the archaeological high probability area. The surveyrecorded

a magnetic anomaly with a perturbation of 100 gammas over the wreck site, but the consulting

archaeologist at the time did not associate it with the location of a significant historic shipwreck.

Subsequently, a study conducted for the MMS with the purpose of determining high probability areas

for the location of historic wrecks in order to reduce the survey interval for those blocks from 150

meters to 50 meters placed the wreck of the New York in Vermilion area, more than 160 kilometers

away from its actual location. As a result, survey requirements for the block containing the wreck

site were reduced to 300 meters, further reducing the chances that MMS would have ever identified

the site. Fortunately, the leader of the team that discovered the wreck shared the location of the site

with MMS in the interest of preserving it from inadvertent destruction by oil and gas development

in the block.

MMS first visited the site of the wreck in July 1997, for the purpose of identifying the wreckage and

conducting an intensive remote sensing survey in order to assess the site's size and extent. There was

a particular concern to investigate the possible relationship between other magnetic anomalies

discovered during the 1988 survey and the shipwreck.

Survey was conducted along northlsouth tracklines spaced 30 meters apart over an area 1,500 feet

wide (east-west) by 4,000 feet long (north-south). Survey instrumentation included a Geometries G866 proton precession magnetometer and a Marine Sonics Seascan 600 kHz side-scan sonar.

Positioning control was maintained with a Trimble NT200D differential GPS receiving the U.S.

Coast Guard differential beacons with an accuracy of ±10 meters. The side-scan sonar receives

positioning input from the DGPS and links the image files with the positioning files. The

magnetometer was time synchronized to the DGPS and magnetic data were output to a computer for

storage. The time-synchronized magnetic and positioning files were later merged in post-processing

to produce a single X, Y, Z coordinate file. The resulting file was contoured using Surfer software.

Magnetic contouring revealed that wreck debris was scattered over the seafloor for a distance of

Many shrimpers maintain personal logs of obstructions within the areas in which they operate. These hangs often

go unreported since this knowledge provides them a distinct economic advantage over competitors.
140

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141

about 450 meters. The principal areas of magnetic perturbation centered over the hull (containing

the steam engine) and a paddle wheel to the east (Figure 2A.3). Several small, concentrated

anomalies were observed curving to the south east from the main wreck site. At present, none of

these anomalies have been tested archaeologically.

Conclusions

The wreck of the New York serves as an important lesson for the MMS/GOMR archaeological

program. The fact that the wreck site lies outside the currently designated high probability area for

historic shipwrecks suggests that the model on which this designation is based needs to be

reevaluated. Secondly, it highlights the importance of developing better public outreach to the sport

diving community and other maritime interests to enlist their trust and cooperation in helping to

locate historic wrecks in the Gulf of Mexico. It is unlikely that MMS would have discovered this

nationally significant site without their assistance and cooperation. Finally, the analysis of the wreck

by MMS demonstrates that the potential site size for a shipwreck on the OCS can exceed 24 ha (61

acres) of bottom land and be characterized by multiple, individual magnetic anomalies scattered over

a wide distance. Since the majority of vessels that wrecked on the OCS did so as a result of

foundering and being literally torn apart during a violent storm, this pattern may be expected to be

repeated at other sites and should be considered as a general rule to guide decisions relating to

activity avoidance zones.

THE WRECK OF THE HATTERAS

A number of important Civil War vessels have been located in state waters, such as the Confederate

ironclads CSS Louisiana in Plaquemines Parish, Louisiana, and the Huntsville and Tuscaloosa in

the Mobile River. The remains of the Union ironclad Tecumseh, whose sinking by a Confederate

mine prompted Farragut's famous order "Danm the torpedoes, full speed ahead!" are well known

off Fort Morgan, Alabama. Only one U.S. warship, however, was sunk at sea in the Gulf This

important shipwreck, the US S Hatteras, has been the subject of repeated investigations by the MMS,

the Texas Historical Commission, and Texas A&M University at Galveston.

The USS Hatteras was a side-wheel steamer acquired by the Navy in 1861 and armed with four 32-

pounder cannon (a 20-pounder rifled cannon was added later). After distinguished service in the

South Atlantic Blockading Squadron, the vessel was transferred to the Gulf Blockading Squadron

on 26 January 1862. In less than a year, the Hatteras captured seven Confederate blockade runners

off Vermilion Bay, Louisiana. Early in 1863, she was ordered to join the squadron under Rear

Admiral David Farragut, who was attempting to retake the key Texas port of Galveston, Texas. The

Civil War in the Gulf is defined by the Northern strategy of the blockade of Southern ports and the

daring attempts by Confederate vessels to run this blockade.

As the blockading squadron lay off the coast on the afternoonof 11 January 1863, a set of sails was

sighted just over the horizon and the Hatteras was ordered to give pursuit. She chased the intruder

for four hours, closer and closer into shore, and farther and farther from her supporting fleet. Finally,

as dusk was falling, the Hatteras came withing hailing distance of the square-rigged, black-hulled
142

Figure 2A.3. Magnetic contour map of the wreck site of the New York.
143

--

Figure 2A.4. The sinking of the USS Hatteras by the CSS Alabama. Courtesy U.S. Navy

Photographic Center.

vessel. Commander Homer C. Blake demanded to know the identity ofthe ship. "Her Britannic

Majesty's Ship Vixen," came the reply. Blake ordered one of Hatteras' boats launched to inspectthe

"Britisher." Almost as soon as the boat was piped away, a new reply came from the mystery ship,

"We are the CSS Alabama!" A broadside from the Alabama's guns punctuated the reply. Within 13

minutes, the Hatteras, sinking rapidly, surrendered (Figure 2A.4).

The Hatteras today rests in 58 feet of water about 20 miles off Galveston. Her 210-foot long iron

hull is completely buried under about three feet of sand. Only the remains of her 500-horsepower

walking beam steam engine and her two iron paddle wheels remain exposed above the sea floor.

Since the site's discovery in the 1970s, MMS has engaged in periodic monitoring of the wreck to

ensure that it is not damaged by surrounding oil and gas lease development. Although the wreck

remains the property of the U.S. Navy, MMS has joined forces with the THC and Texas A&M at

Galveston to preserve this important archaeological treasure for posterity.

The wreck of the US Hatteras is an integral part of the story of the Civil War on the Texas coast, the

defense of which is regarded as one of the greatest military feats of the Confederacy. The ship's

dramatic history, along with the fact that the remains of the vessel are virtually intact, make it one

of the most important underwater archaeological sites in the United States.

HORN ISLAND SHIPWRECK

Another wreck possibly associated with the Civil War in the Gulf was recently documented by

MMS. Loran C coordinates of an historic side-wheel steamship off Horn Island, Mississippi, were
144

Figure 2A.5. Side-scan sonar image of the Horn Island shipwieck (22HR843).

provided to MMS by an informant. Because of the inherent inaccuracy of Loran C, there was a

possibility that this site could lie in federal waters. Side-scan survey and DGPS positioning

confirmed that the vessel lies in Mississippi waters. Information about the site was relayed to the

Mississippi State Historic Preservation office, who had no information about the vessel in their

archaeological site records. The site has been assigned a trinomial designation of 22HR843.

The Horn Island shipwreck is a side-wheel steamship with an apparently intact walking beam engine

and two large boilers visible above the seafloor. From the side-scan image, the vessel measures 53.6

meters long by 10 meters wide (Figure 2A.5). Local informants report that it has an iron hull,

although this has not been confirmed. Research presently is being conducted to identify the wreck,

which most likely dates to the last half of the nineteenth century. Preliminary research suggests that

0

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145

the vessel may be the Heroine, which was built in Glascow in 1862 as a blockade runner (Way 1983,

213). After the Civil War, the vessel was used as a towboat in New Orleans and after 1880 was

converted into a passenger boat on the New Orleans-Bay St. Louis-Biloxi run. The Heroine

disappears from the historical record after 1906, which coincides with a major hurricane that made

landfall on the Mississippi coast. Could the Heroine have been lost in this storm? Is the Horn Island

Wreck the last remains of this vessel? Field work to be conducted as part of the seafloor monitoring

program next summer may answer these questions. Because of its apparently intact condition, the

vessel should be considered to be potentially eligible to theNational Register of 1-listoric Places.

WORLD WAR II SHIPWRECKS

Federal law defines an historic site as at least fifty years old. As a result, wrecks associated with

World War II now meet that criterion. Nearly all the shipwrecks in the Gulf from that period relate

to one causeattack by the German submarines known as "U-boats." U-boat comes from the

German word "Unterseeboot."

During the years 1942 and 1943, a fleet of more than 20 German U-boats cruised the Gulf seeking

to disrupt the vital flow of oil carried by tankers from ports in Texas and Louisiana. They succeeded

in sending 56 vessels to the bottom; 39 of these are now believed to be in state or federal waters off

Texas, Louisiana, and Florida. After their initial, devastating success, U-boat attacks in the Gulf

became rare by the end of 1943 after merchant vessels began cruising in armed convoys. The

opening of the "Big Inch" pipeline from Texas to New Jersey also contributed to freeing the war

effort from relying on ships to transport crude oil.

At least 13 of the U-boat casualties have been discovered, largely through the efforts ofthe oil and

gas surveys. These include the Cities Service Toledo, the She herezade, the K W Gallagher, the R.M

Parker, the DavidMcKelvey, the Hamlet, the Heredia, the Halo, the Bayard, the Benjamin Brewster,

the Gulf Penn, the Alcoa Puritan, and the Robert E. Lee. All of these wrecks have substantial

physical remains on the seafloor and principally were located using side-scan sonar. The depths of

the wrecks range from as little as 36 feet (Benjamin Brewster) to more than 4,000 feet of water

(Robert E. Lee and Alcoa Puritan).

The Cities Service Toledo, lost in the South Marsh Island Area, is fairly typical of the losses to

American shipping during the U-boat war in the Gulf (Figure 2A.6). The Toledo was an 8,192-ton

steamship built in 1918 (Browning 1996, 140). On 10 June 1942, it left Corpus Christi, Texas,

carrying 84,000 barrels of crude oil bound for Portland, Maine. The vessel sailed alone and plied a

nonevasive course, making it a sitting duck for the U-158 under the command of Kapitänleutant

Erich Rostin. Just two days before, Rostin had sunk the freighter Hermis and the tanker

Scheherezade.

Twenty miles east of the Trinity Shoals Gas Buoy, the U-158 fired two torpedoes that struck two

seconds apart on the starboard side amidships in the #6 and #7 tanks at 1:50 a.m. on 12 June (TimesPicayune, 17 June 1942). The vessel immediately listed to starboard and soon was struck by two

more torpedoes in the #4 and #5 tanks. The last torpedo was an incendiary that caused the ship to
146

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Figure 2A.6. The SS Cities Service Toledo.

burst into flames. The Navy gun crew manned their single 5" bow gun as long as possible and fired

3 rounds at a light they believed to be the submarine. Ceasing after the gun's recoil began to tear the

plates from the deck of the badly listing ship, the nine men of the gun crew abandoned the vessel

with the rest of the crew of eight officers and 28 men. The explosion and fire had destroyed the life

rafts and two of the ship's boats. A third boat was launched but the crew could not clear it from the

flaming water surrounding the stricken ship and were forced to abandon it. Seventeen men

abandoned the ship in the remaining lifeboat and were rescued by the Norwegian tanker, S S Belinda,

several hours later. Eight hours after the attack, the tankers SS Gulf King and SS San Antonio

rescued the surviving 13 men in the water. Fifteen men were lost in the attack, including one officer,

ten crewmen, and four armed guards. One of the survivors, who had abandoned a law career for life

as a naval gunner, commented from his bed in a Marine hospital: "Law is easier any day" (Times

Picayune, 17 June 1942).

One of the worse casualties in human terms of the U-boat war in the Gulf was the Heredia, a 4,700

ton freighter owned by the United Fruit Company (Figure 2A.7). The Heredia was bound for New

Orleans from Puerto Barrios, Guatemala, with a cargo of 40,000 stems of bananas and 5,000 bags

of coffee when she was attacked by the U-506 on 19 May 1942 (Navy Dept. 1 942a; Browning 1996,

111). Three torpedoes struck the vessel, causing her to plunge beneath the sea stern first within three

minutes. Thirty-six men lost their lives in the attack. Among the 23 survivors were two children, a
p

147

Figure 2A.7. The SS Heredia.

9-year-old boy and an 11-year-old girl, who later recounted that sharks approached her close enough

to tickle her feet as she clung to a hatch cover for 15 hours awaiting rescue (Times-Picayune, 25 May

1942). In only ten days between 10 May and 20 May 1942, the same U-boat also sank the tankers

Aurora, Gulfpenn, David McKelvey, William C. McTarnahan, Sun, Gulfoil, and Halo (Wiggins

1995, 234f). The captain of U-506, Erich Wilrdemann, was subsequently awarded the Iron Cross

(First Class) and, later, the coveted Knights Cross. WUrdemann was responsible for sinking 16

vessels during his career, costing the Allies nearly 87,000 tons of shipping, before the U-506 was

itself sunk by anUS B-24 Liberator aircraft off Vigo, Spain on 12 July 1943.

Between May 1942 and December 1943, German U-boats harassed American shipping in the Gulf

with near impunity. Only one Nazi submarine, the U-i 66, is believed sunk in the Gulf; it has yet to

be discovered (Figure 2A.8). The U-166 was commissioned on 23 March 1942. It departed

Kristianstad, Norway, on its first patrol to the North Atlantic under the conimand of Oberleutnant

Hans-GUnther Kuhlmaxm on 1 June. Returning to base at Lorient, France, on 10 June withoutscoring

any successes, the U-166 departed for the Gulf seven days later. Kuhlmann's first victim in the Gulf

was the Carmen, a small freighter registered in the Dominican Republic. Two days later on 13 July

the U-166 claimed as its second kill the Oneida, an unarmed 2300-ton freighter owned by the Ford

Motor Company that was steaming in ballast for Punta Gorda, Cuba. The American trawler Gertrude

was Kuhlmann' s third victim. Probably stung by the failure of his first cruise, and the frustrating lack

of important targets as his second cruise neared its end, Kublmann was no doubt elated when the

5,184-ton passenger steamer Robert E. Lee unwittingly sailed into his path. The Robert E. Lee was

sailing from Port-of-Spain, Trinidad, to New Orleans under escort of the PC-566. Aboard the vessel

were 268 passengers who, ironically, were mostly survivors of other sinkings. Lookouts on the

Robert E. Lee spotted a torpedo 200 yards before it struck just aft of the engine room (Browning

1996, 194). The explosion destroyed the #3 hold and vented through the B and C decks, wrecking

the engines, the radio equipment, and the steering gear. The ship sank stern first within 15 minutes

as the PC-566 began dropping depth charges (Figure 2A.9). One of the Robert E. Lee's officers, nine

of her merchant crew, and 15 passengers died in the attack. Survivors were picked up by the PC-566,

the SC-519, and the tug Underwriter and transported to Venice, Louisiana.
148

Figure 2A.8. A Class IXC GenTnan U-boat, the same type as the U-166.

What became of the U-166 after the attack on the Robert E. Lee remains a mystery. This much is

known for certain: the submarine never returned and was presumed lost. The crew of the PC-566

reported that a small oil slick followed their depth charges (Navy Dept. 1 942b), but this was a

common tactic employed by submariners to trick their attackers into believing that the boat was

damaged. Two days after the attack on the Robert E. Lee, the crew of a J4F-1 Grumman torpedo

plane spotted an U-boat on the surface in shallow water 20 miles south of Isles Demieres, Louisiana,

in what is now South Timbalier Area. As the plane turned to attack the submarine, it was spotted by

the Germans and the sub crash-dived. After launching their 325-pound depth charge from an altitude

of 250 feet, the aviators saw a sheen of oil come to the surface and believed that they had damaged

the sub. However, it is hard to imagine that the sub would have remained undiscovered in only about

60 feet of water after 56 years. In fact, it is not even certain that the sub spotted by the flyers was the

U-i 66. Declassified German documents reveal that there were five U-boats patrolling the Gulf in

August 1942. It seems more likely that the U-166 was damaged by the depth charges from the PC566 and sank somewhere in the deep abyss of Mississippi Canyon. Our best hope for finding the lost

sub now is the deep water exploration currently being undertaken by the oil and gas industry.

The discovery of and continued research on World War II shipwrecks in the Gulf gives us a new

appreciation for the strategic importance of this region to the war effort. At great personal risk, the

U.S. Merchant Marine kept up the flow of oil to fuel the Allied war machine. The evidence of their

sacrifice lies beneath the waves on the Outer Continental Shelf These wrecks deserve our protection

not only as war graves, but as silent monuments to the courage of the Merchant Marine and the role

of the Texas and Louisiana oil industry in the defeat of the Axis powers.
149

SS ROBERT E. LEE

Figure 2A.9. The SS Robert E. Lee, superimposed over the side-scan sonar record of the

shipwreck. Courtesy John E. Chance & Associates, Inc.
150

CONCLUSIONS

The Seafloor Monitoring Program is having a significant effect on our ability to interpret and

understand underwater archaeological remains in the Gulf of Mexico.Not only can we pro actively

insure that MMS avoidance mitigations actually are applied, but we can, for the first time, take the

opportunity to examine remote sensing targets in the field to determine if they are, in fact, historic

shipwrecks or merely modern debris. By developing a better understanding of what shipwrecks in

the Gulf actually look like, we are able to make better, and we hope, less restrictive management

decisions to insure their preservation for future generations of Americans.

AUTHOR'S NOTE

The Horn Island shipwreck (22HR843) discussed here was posited at the time of the ITM to be the

wreck of the Heroine. Since that time (1998) the MMS has sponsored additional fieldwork and

historical research at the site to identify the vessel. Subsequently, the shipwreck has been identified

positively as the Josephine. The Josephine was constructed by Harland & Hollingsworth in

Wilmington, Delaware, in 1867 and sank during a winter storm on 8 February 1881. The vessel was

operated by the Charles Morgan Line, the principal steamship line serving the Gulf Coast throughout

most of the nineteenth century.

REFERENCES

Browning, Robert M., Jr. 1996. U.S. Merchant Vessel War Casualties of World War II. Naval

Institute Press, Annapolis.

Daily Picayune. 1846. Wreck of the New York. 10 September, morning edition.

Hayes, Charles W. 1971. Galveston, History of the Island and City. Jenkins Garrett Press, Austin,

Texas. (Originally written in 1879)

Heyl, Erik. 1969. Early American Steamers. Buffalo.

Navy Department. 1942a. Summary of statements by survivors of the SS "HEREDIA," American

passenger-cargo vessel, 4,732 G.T., United Fruit Company, owners. Memo For File, Office of

the Chief of Naval Operations, 5 June 1942.1942b Summary of statements by survivors of the

SS "ROBERT E. LEE," U.S. passenger-cargo vessel, 51 84G.T., owner: Eastern Steamship Co.,

operated by Alcoa Steamship, Inc., as agents for War Shipping Administration. Memo ForFile,

Office of the Chief of Naval Operations, 13 August 1942.

National Archives and Records Administration. 1843. Vessel Registration No. 340, Port ofNew

York.

New Orleans Gazette. 1846. Loss of the Steamship New York. 10 September.
Dr. Jack B. Irion joined the Minerals Management Service in August 1995 with the title of marine

archaeologist. Prior to MMS, Dr. Irion served as vice president for Nautical Archaeological Services

with the consulting firm of R. Christopher Goodwin & Associates, Inc., in New Orleans, Louisiana.

For over 15 years, Dr. Irion provided archaeological consulting services to the Baltimore, Charleston,

Mobile, New Orleans, Pittsburgh, Philadelphia, Savannah, Vicksburg, and Wilmington Districts of

the Corps of Engineers, as well as to the Maryland Port Administration, and the State of Tennessee.

Dr. Irion received his B.A. (1974) and M.A. (1977) in Archaeological Studies from The University

of Texas at Austin. He was awarded his Ph.D. from the Institute of Latin American Studies of the

University of Texas in 1991. During his career, Dr. Irion has specialized in conducting remote

sensing surveys for shipwrecks, which succeeded in locating such historically significant vessels as

the C.S.S. Louisiana, the sailing barque Maxwell, and the steamboats Princess, and Kentucicy. In

addition, he has directed numerous diving investigations on historic shipwrecks, including the

steamship Columbus and the Civil War gunboats Tawah and Key West. Most recently, he has

participated in MMS investigations of the Civil War vessel U.S.S. Hatteras and the steam packet

New York.

BIOLOGICAL CHARACTERIZATION AND MONITORING OF SONNIER BANK

Mr. Gregory S. Boland

Minerals Management Service

Gulf of Mexico OCS Region

ABSTRACT

Sonnier Bank is a siltstone mid-shelf bank resulting from salt diapirism similar to most other

topographic features along the northern Gulf of Mexico continental shelf. Though not a true coral

reef, a remarkable biota of more than 100 species of fish and a nearly 100% cover of attached

invertebrates including eight species of coral are represented. Sonnier Bank is very similar to, and

in many respects better developed than Stetson Bank, which is now part of the Flower Garden Banks

National Marine Sanctuary.

The Minerals Management Service (MMS) has initiated a program to farther characterize the biota

and community stability at Sonnier Bank. This program is part of a multiyear monitoring effort.

Repetitive photographic stations installed by a previous project of the nonprofit organization Gulf

151

Way, Frederick. 1983. Way's Packet Directory. Athens, Ohio.

Wiggins, Melanie. 1995 Torpedoes in the Gulf. Texas A&M University Press, College Station,

Texas.
152

Reef Environmental Action Team (G.R.E.A.T.) are being utilized similar to the ongoing Flower

Garden Banks long-term monitoring project. Initial components of the program include continuing

repetitive photographic samples, habitat mapping and characterization, quantitative quadrat counts,

an in situ thermistor, and diver-performed fish census.

The initial results from a limited number of repeated quantitative photo stations indicate a very

dynamic benthic community with the dominant sessile invertebrate fauna exhibiting substantial

changes in percent cover on an annual basis. Reef fish and invertebrate census data will be

addressed.

IINTRODUCTION

Sonnier Bank, located 128 km south of Vermilion Bay, Louisiana (28° 22.2' N, 92° 27.08' W), is

a siltstone mid-shelf bank resulting from salt diapirism similar to most other topographic features

along the northern Gulf of Mexico (GOM) continental shelf. Sonnier Bank was formerly named

Three Hickey Rocks by Texas fishermen and sport divers prior to the mid 1 970s. It was named after

Farley Sonnier around 1977 in honor of his extensive work with Gulf of Mexico fish fauna

(Mr. Sonnier passed away in 1987). Sonnier is the fourth and probably only other offshore bank

located in clear continental shelf waters that can be easily visited by recreational scuba divers. The

East and West Flower Garden and Stetson Banks being the other three, are now all part of the Flower

Garden Banks National Marine Sanctuary. Claypile Bank is the next shallowest GOM topographic

feature with its peak coming to within only 42 m of the surface, a very deep dive for most scuba

divers.

The first scientific investigation of Sonnier Bank was performed in 1977 as part of a BLM (now

MMS) funded study by Texas A&M University using the research submersible Diaphus as part of

the Northwestern Gulf of Mexico Topographic Features Study (Bright and Rezak 1978). Until the

efforts of the Gulf Reef Environmental Action team (G.R.E.A.T.) and MMS in 1996, there had been

no attempts to revisit this diverse topographic feature for research purposes.

Environmental concerns for topographic features in the Gulf of Mexico relating to the long-term

effects of oil and gas production activities are the responsibility of MMS. An oil and gas lease

stipulation has established no-activity zones around topographic features including Sonnier Bank

since 1973. In addition to this stipulation, MMS has also funded monitoring efforts at a number of

features, primarily the Flower Garden Banks. Recently, MMS has become actively involved in a field

monitoring program using in-house resources and personnel. As a part of this initiative, Sonnier

Bank will be visited on an annual basis to further characterize the biota and community stability as

part of a multiyear monitoring effort.

General Description

The most prominent characteristic of Somiier Bank is the physical nature of this topographic feature.

Pinnacle formations rise steeply from a surrounding bottom depth of approximately 61 m coming

to within 18 m of the surface in one location. The similarity of surficial geology between Sonnier
153

and Stetson Banks was noted as early as 1976 by Bright et al. (1976) prior to Texas A&M having

visited what was then called Three Hickey Rocks (using underwater photographs). The numerous

individual peaks are believed to be the result of the collapse of the crest of the underlying salt diapir

(Rezak et al. 1983). Two of approximately eight peaks occurring within the total area ofSonnier

Bank have been investigated; both of these rise to a depth of less than 22 m. It is believed that at least

one other peak is shallower than 40 m (where reasonable duration research dives could be

performed) and will be investigated during the next effort scheduled for 1999.

The initial study site chosen and worked on exclusively during 1996 is the only one depicted on

existing bathymetric charts shallower than 42 m. The total area of the bank rising above the

surrounding bottom of 60 m is approximately 600 hectares, but this site encompasses an area only

0.3 hectare above the 30-m contour. During year two, a second small site not appearing on charts

was investigated and found to rise to within 18 m of the surface. Located only about 150 m to the

north of Peak 1, it was designated Peak 2. This peak is even smaller with an area above the 30 m

contour encompassing only about 0.1 hectare.

METHODS AND RESULTS

Fish Census

Fish community census data was obtained by the "Roving Diver Technique" during two separate

years to date. The technique utilizes teams of trained divers who record species and relative

abundance (four ranks) of all reef fish species seen around the reef throughout their dive. This is the

same technique used to perform fish census reported in these proceedings forthe Flower Gardens

and Stetson Banks by Pattengill (1998). After returning to the surface, observations are transferred

to optically read data forms developed by the Reef Environmental Education Foundation (REEF).

Surveys were only conducted in the immediate vicinity of each peak. During 1996, only the 22-m

peak was investigated on 1-2 July; and on 30 September-i October 1997, both the 22-rn and the 18-

m peaks were surveyed.

During the 1996 census, a total of 109 species of fish were identified by census teams. In 1997 a total

of 104 species of fish was reported by Childs (1997), 89 species at the shallower 1 8-m peak and 80

species at the 22-rn peak. Although five fewer species overall were observed in 1997, a total of 16

new species was reported raising the two-year total to 125 taxa. The most abundant taxa was the

creolefish (Paranthias furcfer). Similar to Stetson Bank, this plankton-feeding serranid was

observed in large groups at the edges of the peak features. Cocoa damselfish (Ste gastes variabilis)

were also very numerous but a distant second in terms of relative numbers. One other notable species

observed in moderate numbers was red snapper (Lutf anus campechanus). This species is rarely seen

above 30 m at the Flower Gardens or Stetson Banks but was common at the edges of the peaks.

Habitat associations of observed species was dominated by those closely associated with reef

structures while 17% of the species were epipelagic in nature, those species that do not have a close

affinity to reef structures such as mackerals and cobia.
154

Invertebrates and Algae

General characterizations of the Sonnier Bank benthic communities were made by this author in

1996 and reported to MMS by Gittings and Harper in 1997. Cover of living organisms on pinnacle

substrate is extremely high, close to 100% in many areas and generally exceeding 70% dominated

by a variety of species of sponges, algae, and also the fire coral, Millepora alcicornis. Sponge cover

was dominated by the stinging sponge NeojIbularia nolitangere. Large ball sponges of the genera

Ircinia were also commonly observed. Dozens of other sponge species, which are not reliably

identified in situ, have been noted during both sampling years. Gittings and Harper (1997) reported

the dominant algae species as the brown alga Lobophora variegata. Other algal species were also

common including the brown alga, Diclyota. On the crest of some of the pinnacles, sabellid womis

were very abundant. Night observations noted unusual concentrations of the fireworm Hermodice

caruncualta covering the bottom, at least several per square meter over most areas.

Mollusks were abundant on both peaks dominated by small ceriths (Cerithium spp.) very similar to

Stetson Bank. A number of other mollusk taxa, including cowries, arc shells, pen shells and a

number of thorny oysters, were also noted during both years . Thorny oysters are a prized catch for

collectors, and their abundance may indicate the degree of isolatioll Sonnier Bank derives as a result

of its distance from shore and major ports.

Scleractinian corals reported during 1996 included small colonies of Oculina df[usa,

Stephanocoenia intersepta, Phylangia americana, Madracis decatus, and M. mirabilis. Two

additional scleractinian coral species were reported by Gittings and Harper in 1997. These included

M. pharensis and Siderastrea radians.

Other large motile invertebrates were recorded, although 110 systematic surveys have been performed

to date. Other observations will not be detailed here; however, several very large spiny lobsters

(Panulirus argus) are of particular note. In addition to the repetitive photographic station,

quantitative surveys of large motile invertebrates (e.g., lobsters and urchins) will be incorporated into

the monitoring efforts beginning in 1999.

Repetitive Station Photography

Repetitive photographic stations installed by a previous project of the nonprofit organization Gulf

Reef Environmental Action Team (G.R.E.A.T.) are being utilized similar to the ongoing

MMS/NOAA-funded Flower Garden Banks long-term monitoring project. A total of 20 permanent

station marking pins were installed in 1996. Each station is photographed from a height of 1.05 m

using a fixed camera framer, a 15-mm wide angle Nikonos lens, and two 225 watt-second strobes.

The base of the 1.05-rn post is placed at the pin anchored in the bottom. The framer has a compass

and bubble level located next to the camera to accurately align the camera. The bubble level is

centered and the compass oriented to the north prior to each station photograph. The resulting image

includes an area of 2 m2.
155

During the two-day effort in 1997, only a few stations were relocated and photographed. It is

believed that most all of the station pins and tags were heavily overgrown by sponge and algae.

Initial interpretation of repeated images indicates that the growth and percent cover of benthic biota

is highly variable with substantial changes in sponge and algal cover over a one-year time span. With

the use of underwater maps and landmarks, it is believed that most all the installed stations can be

relocated in the future.

Recording Thermistor

An in situ electronic thermistor programmed to record water temperature every 4 hours was installed

at the site of the anchor mooring on 1 July 1996. It was not relocated during the 1997 field effort due

to probable overgrowth of sponge and algae. However, it does have the capability of obtaining data

for one additional year until MMS is able to return to the bank and perform a more intensive search

for the small instrument. Three new thermistors will replace the one on site during the upcoming

1999 effort. One unit will be located on the crest of the 1 8-m Peak 2, and the other two will be

installed at a new deep site (40 m and at the previously used shallow site (25 m) on the 22-m

Peak 1. Temperature data recovered from these instruments will be a valuable tool forinterpretation

of relationships between potential climate change and change in community composition.

SUMMARY

Initial components of the program have included quantitative repetitive photographic samples,

habitat mapping and characterization, a recording in situ thermistor and diver-performed fish census.

Continuing future monitoring efforts will include the following components:

continued sampling of 2 m2 repetitive photographic stations;installation of permanent station

markers for repetitive photography on the shallow Peak 2;

benchmark installation for four 100 m video transects located on two peaks;

installation of additional recording thermistors;

macroinvertebrate surveys;

continued fish census; and

ROY surveys of communities below 40 m on at least two pinnacles.

Bright and Rezak (1978) described Sonnier Bank as very healthy with "no evidence of past mass

mortalities or large scale deleterious environmental effects attributable any cause." There had been

at least nine exploratory wells drilled within 9 km of the bank during the 1 960s prior to their report.

The observations of Bright and Rezak are very similar to what has been found at Sonnier Bank 20

years later. At least six active oil and gas platforms are currently operating within 15 km of the bank,

and Vermilion Block 305 is currently an active lease, although no planned exploration drilling

activities are known. The MMS topographic feature stipulation, including a no-activity zone and

shunting of discharges within a 4-mile zone, may play a significant role in future protection of

Sormier Bank. Continued monitoring efforts at this unique topographic feature will provide resource

managers and scientists with insight into natural changes, as well as the potential impacts from the

long-term energy development in the surrounding area.
156

ACKNOWLEDGMENTS

A large portion of the information obtained during these studies was collected by many different

individuals. Fish census data was coordinated by Dr. Ann Bull in 1996 and Jeff Childs in 1997.

Biological characterization data was also obtained by Drs. Steve Gittings and Don Harper in 1997.

Mr. Les Dauterive coordinated MMS participation during both field efforts. The Gulf Reef

Environmental Action Team (G.R.E.A.T., Houston, Texas) coordinated the initial project in 1996

and provided the funding for materials and a portion of ship time. The MMS funded one day of ship

time in 1996 and the entire cruise in 1997. The initial long-term themiistor was donated to the

project by the author.

REFERENCES

Bright, T.J. and R. Rezak. 1978. South Texas Topographic Features Study. Final Report to Bureau

of Land Management, DOT. Contract #AA550-CT6-1 8. 772 p. NTTS Order No. PB-294-768/AS

Childs, J. 1997. Summary report for Minerals Management Service on the icthyofaunal surveys

conducted at Sonnier Bank in the northwestern Gulf of Mexico, September 1997. Project Report

to Minerals Management Service, DOT. 7 p.

Gittings, S. and D. Harper. 1997. Sonnier Bank biological characterization, September/October,

1997. Cruise report to Minerals Management Service, DOT. 6 p.

Pattengill, C. 1999. Reef fish census results at Stetson and the Flower Garden Banks. Proceedings:

Eighteenth Annual Gulf of Mexico Information Transfer Meeting (this volume). Minerals

Management Service, DOT.

Rezak, R, T.J. Bright and D.W. McGrail 1983. Reefs and Banks of the northwestern Gulf of Mexico:

Their geological, biological, and physical dynamics. Final Report to Minerals Management

Service, DOT. Contract #AA851-CT1-55.

Rezak, R., T.J. Bright, and D.W. McGrail. 1985. Reefs and Banks of the Northwestern Gulf of

Mexico: Their Geological, Biological and Physical Dynamics. New York: Joim Wiley and Sons.

259 pp.

Greg Boland is a biological oceanographer with Minerals Management Service's Gulf of Mexico

OCS Region, New Orleans. He started at MMS in April of 1998 after 10 years as a Senior Research

Associate with the Department of oceanography at Texas A&M University (where he previously

received his Master's in Oceanography) arid a previous 10 years with the consulting firm of LGL

Ecological Research Associates in Bryan, Texas. His current professional interests include coral reef

and chemosynthetic community ecology and energy platform communities. At MMS, Mr. Boland
157

is currently an analyst for fisheries and deepwater benthic community issues and is also a member

of the MMS scientific dive team.

THE MONITORING AND ANALYSIS OF OPERATIONS

SITES FOR REGULATORY COMPLIANCE

Mr. Les Dauterive

Minerals Management Service

Gulf of Mexico OCS Region

In response to the Government Performance and Results Act and reports of anchor scars and

associated seafloor impacts on nearby Biological Pinnacles offshore Alabama, the Minerals

Management Service (MMS) last year started a program to monitor the seafloor for impacts that

could be associated with oil and gas development. Dr. Jack Irion and Dr. Rik Anuskiewicz, marine

archaeologists, were designated principal investigators and managers of the program. The Region

purchased a Marine Sonic Technology SeaScan sonar system and Digital Global Positioning System

for program implementation and systematic survey and search of seafloor impacts. In addition to Drs.

Rik and Jack, the Region's dive team has provided the necessary field support and visual groundtruthing for verification of the side-scan sonar images.

An important part of the MMS Seafloor Monitoring Program has been the application of the sidescan sonar technology for surveying the seafloor and underwater operations activity sites for possible

industry violation of MMS operations compliance regulations. This is not to say that the industry is

willfully violating their underwater operations responsibility, but non-compliance of regulatory

requirements do occur, be they willful or not. The MMS has had a long standing inspection program

for monitoring the drilling and production operations aspects of the offshore program and incidences

of non-compliance (INCS) with regard to this activity are occasionally issued. The survey of

underwater operations sites is the first effort by MMS to police the industry's underwater operations activities.

The success of the MMS Seafloor Monitoring Program is a function of the scientific expertise

available to operate the program, available time on the part of the MMS staff to do the work, and

offshore conditions in which a monitoring project can be safely and successfully accomplished.

Over the past two summers the Region's Seafloor MonitoringProgram team has used the SeaScan

sonar system technology to survey a variety of field operations sites and locations. The team's

objective is to provide Field Operations with empirical data of seafloor anomalies and obstructions

for evaluation of possible violations of compliance with MMS operations regulation.
158

In close working coordination with the office of Field Operations, the seafloor monitoring team

conducted field projects applicable for survey by the SeaScan sonar system. Side-scan sonar surveys

were conducted at:

Seafloor well stubs and subsea well completions

Site-Clearance locations

A debris field near a well site location

An oil leak near an artificial reef site

SEAFLOOR WELL STUBS AND SUBSEA WELL COMPLETIONS

The seafloor monitoring team's efforts to side-scan the seafloor to determine well stub exposure at

or above the seafloor, presence of protective dome covers over the well stub, or evidence of trawl

hangs and shrimp trawl damage, have so far produced minimal results. This we believe was due

partly to incorrect location coordinates in the well stub data base, and the difficulty in surveying for

and locating these sites. The survey for a sub-sea well completion did produce an image of the subsea completion tree, surface buoy, and anchor chain marking the sub-sea completion site. An attempt

by the MMS divers to follow the surface buoy anchor chain to the subsea tree for visual verification

was abandoned. The anchor chain was immediately lost in the very fine, unconsolidated bottom

sediment, reducing the visibility at the seafloor to zero.

SITE CLEARANCE LOCATIONS

The seafloor monitoring team's efforts to scan the seafloor at site clearance locations for verification

that the seafloor is free of operations debris produced some results. Two site clearance locations were

examined by the side-scan sonar survey. At one location a large depression, believed to be the

abandoned well site location was observed and some small hard returns in the acoustic record may

indicate small debris on the seafloor. At the other location a shell mat or drill cuttings pile

surrounding a seafloor depression showed clearly as a bright spot in the acoustic record because of

the difference in the hardness between the mat or and/or pile and the surrounding sediment. An

approaching squall precluded the MMS dive team from conducting a visual ground-truthing survey

at these site clearance location.

A DEBRIS FIELD NEAR A WELL SITE LOCATION

Review of a routine site-specific hazard block survey revealed a debris field on the seafloor near a

proposed drill site. Since the debris field appeared to be oil field related and a potential hazard to

navigation, the site was surveyed and investigated by the seafloor monitoring team. The side-scan

survey revealed 2 parallel rows of seafloor protrusions with 3 protrusions in each row. The rows are

60ft apart and the protrusions are 50fl apart in each row. A central cluster of debris was observed on

the acoustic record between the rows of protrusions. MMS divers were dispatched to visually

investigate the composition and vertical height of the protrusions. The divers found the protrusions

to be heavy concreted steel piles protruding 5-6 ft above the bottom of the seafloor. Upon our return

to the office, search of the lease block file for past operations revealed that the location of the debris
159

field corresponded to a well which was drilled, plugged and abandoned in 1980. The piles were

found to be pin piles placed as skirts around a drilling barge that was commonly use to drill wells

in shallow water in this area. The central cluster of debris was probably the location of the well.

Because the site presents a potential hazard to navigation and conflict with commercial shrimp

trawling the location's precise Digital Global Positioning System (DGPS) coordinates were provide

to the U.S. Coast Guard's automated Wreck and Obstruction Information Service for publication as

a Notice to Mariners. Our Field Operations office is investigating for the identification of the

responsible operator for removal of the seafloor obstruction.

OIL LEAK NEAR AN ARTIFICIAL REEF SITE

The Texas Parks and Wildlife Artificial Reef Program office requested MMS assistance in

pinpointing an oil leak near their Matagorda liberty ship artificial reef site offshore Texas. The liberty

ships, an oil and gas well, or a pipeline were suspected sources of the leak. In response to the request,

the seafloor monitoring team conducted a side-scan sonar survey and captured images of the three

liberty ship reefs. Review of the MMS lease file records shows no oil and gas well was ever drilled

on this lease and no pipelines exist in the lease. A positioning fix over the point where the oil was

observed to come to the surface indicated that the leak is likely coming from the bow of the southern

most ship. The surface expression of the leak was some 140 ft from the DGPS center coordinates

of this ship. The side-scan sonar acoustic record indicate that there are no other possible sources for

the leak visible on the seafloor.

Weather this past summer has disrupted the team's effort to accomplish projects scheduled this year.

However, the MMS Seafloor Monitoring Program has been funded for fiscal year 1999 and the

seafloor monitoring team will continue its work and improve its capabilities to survey for impacts

to the seafloor associated with oil and gas development in the Gulf of Mexico.

Les Dauterive is a Senior Staff Environmental Scientist with the Minerals Management Service

(MMS), Gulf of Mexico OCS Region, Office of Leasing and Environment (LE). Les has been with

the MMS for 24 years. Prior to his present position Les was a supervisor for 15 years in the

Environmental Operations Section of LE, which is responsible for the supervision of MMS ' s review

and environmental assessment of industry's operations activity. Presently, Les is the MMS Diving

Safety Officer responsible for the management of the MMS Scientific Diving Team and Program,

and is the Region's Artificial Reef coordinator responsible for the liaison and coordination of the

Gulf's Rigs-to-Reefs program. Les is an avid SCUBA diver and certified Dive Master with over 20

years of diving experience. He is a member of the American Academy of Underwater Scientists and

has managed MMS scientific diving operations throughout the Gulf for the protection of biological

natural reefs and banks, and for the assessment of oil and gas production and retired platforms as

artificial reefs. Les is a graduate of the University of Southwestern Louisiana with a B.S. degree in

biology and is also a graduate of McNeese State University with a M.S. degree in environmental

science. Les has received the U.S. Department of the Interior's (USD01) Point of Light award for

his leadership of the MMS dive team's participation as volunteers in the Aquarium of Americas
160

(AOA) diver naturalist program, and is a member of the AOA Dive Safety Board. Les also received

the USD01 Safety Management Award in recognition of his outstanding achievement in the MMS

diving safety program.
Fish Community Structure:

Mississippi/Alabama Pinnacle Trend

SESSION 2B

FISHERIES MANAGEMENT AND BIOLOGY

Chair: Mr. Gregory Boland

Co-Chair: Dr Ann Scarborough Bull

Date: December 8, 1998

Presentation Author/Affiliation

Essential Fish Habitat (EFH) Mr. William Jackson

National Marine Fisheries Service

A Reef Fish Monitoring Program at the Dr. Christy V. Pattengill-Semmens

Flower Garden Banks National Marine Texas A&M University

Sanctuary, Northwest Gulf of Department of Biology

MexicoBaseline Results

Sharks and Rays of Stetson and the Flower Mr. Jeff Childs

Garden Banks Department of Wildlife & Fisheries Sciences

Texas A&M University

Dr. Kenneth J. Sulak

Mr. Douglas C. Weaver

Florida Caribbean Science Center

U.S. Geological Survey -

Biological Resources Division

Dr. Steve W. Ross

North Carolina National Estuarine

Research Reserve

Center for Marine Research

161

Trophic Subsidies in the Twilight Zone: Mr Douglas C. Weaver

Food Web Structure of Deep Reef Fishes Dr. Kenneth J. Sulak

along the Mississippi- Alabama Outer Florida Caribbean Science Center

Continental Shelf U.S. Geological Survey -

Biological Resources Division

Status of the Gulf of Mexico Red Snapper Dr. Benny J. Gallaway

Stock: Another Perspective LGL Ecological Research Associates, Inc.
ESSENTIAL FISH HABITAT (EFH)

Mr. William Jackson

National Marine Fisheries Service

"One of the greatest long-term threats to the viability of commercial and recreational fisheries is

the continuing loss of marine, estuarine, and other aquatic habitats. Habitat considerations should

receive increased attention for the conservation and management offishery resources of the United

States."

Magnuson-Stevens Act, 1996

MANAGEMENT OF MARINE FISHERY RESOURCES

Living marine resources constitute valuable and renewable resources that contribute to the food

supply, economy, welfare, health, and recreational opportunities of the nation. In 1976, the

Magnuson Fishery Conservation and Management Act (Magnuson Act) established a management

system to more effectively utilize the marine fishery resources of the United States. It established

eight Regional Fishery Management Councils (Councils), consisting of representatives with

expertise in marine or anadromous fisheries from the constituent states. In order to develop fishery

management plans (FMPs) for the conservation and management of fishery resources, Councils use

input from the Secretary of Commerce (Secretary), the public, and panels of experts. After approval

by the Secretary, the National Marine Fisheries Service (NMFS) implements and enforces the

management measures in the FMP.

As amended in 1986, the Magnuson Act required Councils to evaluate the effects of habitat loss or

degradation on their fishery stocks and take actions to mitigate such damage. In 1996, this

responsibility was expanded to ensure additional habitat protection.

On 11 October 1996, the Sustainable Fisheries Act (Public Law 104-297) became law which, among

other things, amended the habitat provisions of the Magnuson Act. The re-named Magnuson-Stevens

Act (Act) calls for direct action to stop or reverse the continued loss of fish habitats. Toward this

end, Congress mandated the identification of habitats essential to managed species and measures to

conserve and enhance this habitat. The Act requires cooperation among NMFS, the Councils, fishing

participants, Federal and state agencies, and others in achieving the essential fish habitat (EFH) goals

of habitat protection, conservation, and enhancement.

Identification of EFH and Threats to EFH

The Secretary, acting through NMFS:

must develop regulatory guidelines that assist Councils to incorporate EFH provisions into

all FMPs, i.e., the description and identification of EFH, identification of adverse impacts

163
164

to EFH from both fishing and non-fishing sources, and identification ofmeasures to further

the conservation and enhancement of EFH.

in consultation with participants in the fishery, must provide Councils with recommendations

and information for the preparation of EFH amendments.

will coordinate with Federal and state agencies, industry and conservation groups to reduce

threats to EFH.

must review relevant Department of Commerce programs to ensure they further the

conservation and enhancement of FF14.

The Councils, in accordance with NMFS ' s guidelines:

must amend their 36 current FMPs with EFH provisions by the statutory deadline of 11

October 1998. Any new FMPs developed after the deadline must also meet these standards.

NMFS must also amend its 3 Secretarial FMPs in the same manner.

must identify EFH in narratives and on maps using the best information available. They

should develop partnerships with Federal and state resource agencies, researchers, and other

interested parties to foster the exchange of informationon distributions of managed species,

distributions of habitats and threats to these habitat, to assist in the description and

identification of EFH.

must act to minimize adverse impacts on EFH from fishing activities, to the extent

practicable.

must identify potential non-fishing sources of adverse impacts on EFH, and should work

within watershed planning structures to further the goals of EFH.

should develop proactive measures and partnerships to enhance and restore lost or degraded

EFH.

Coordination, Consultation, andRecommendations on EFH: The Magnuson- Stevens Act and NMFS

regulations require interagency coordination and consultation to further the conservation and

enhancement of EFH:

a After EFH amendments have been approved, NMFS will distribute to agencies and other

parties information and maps detailing the locations and potential threats to EFH.

Federal agencies must consult with NMFS regarding any action or proposed action that may

adversely affect EFH. The regulations strongly encourage using existing procedures for

environmental reviews in order to streamline this process. In the absence of an existing

process, the regulations establish procedures to accomplish the mandated consultations.

Any Council(s) may comment and make recommendations to NMFS and any Federal agency

undertaking actions that may adversely affect the habitat, including EFH, of any fishery

resource under its authority; and must comment if the action may adversely impact the

habitat of an anadromous fishery resource under its authority.

After receiving infonnation from a Council or Federal or state agency concerning an action

or proposed action that would adversely affect any EFH, NMFS must recommend measures

to the Federal or state agency to conserve such habitat.
165

Within 30 days of receiving aNMFS EFH recommendation, a Federal agency must respond

in writing to NMFS and any Council(s), if appropriate. The response should detail the

measures that will be taken to avoid, mitigate, or offset the adverse effects to EFH and

explain the reasons for any actions inconsistent with the NMFS EFH recommendations.

Streamlining the consultation process:

NMFS currently participates in interagency enviromnental coordination or consultation

processes under the Fish and Wildlife Coordination Act, the National Environmental

Protection Act, the Endangered Species Act, the Federal Power Act, and the Clean Water Act

for many of the actions that will be covered under the EFH mandate. Where these existing

processes can satisfy the requirements of EFH consultations, such procedures will be used

to meet the consultation requirements of the Magnuson-Stevens Act.

The regulations outline a flexible system of consultation procedures ifno existing processes

are available. It ensures that the level of consultation is commensurate with the action's

potential impact on EFH:

Programmatic Consultation for specific agency programs consisting of similar actions

that may adversely affect EFH. - General Concurrence for categories of actions with minimal adverse effect on EFH.

Abbreviated Consultation for individual actions with minor adverse effects on EFH.

Expanded Consultations for review ofprojects with the potential for substantial adverse

impacts on EFI-I.

NMFS is committed to working with the Councils, affected Federal and state agencies, fishing and

non-fishing industries, conservation groups, academia, land owners, and the general public to ensure

that EFH provisions are understood and well coordinated, thereby providing effective protection for

essential fish habitats as Congress envisioned. NMFS will seek working agreements with

organizations and provide many avenues for public input to the EFH process. Partnerships with other

Federal agencies, state resource agencies, and non-governmental organizations will enhance the

process.

For further information contact: Office of Habitat Conservation, NOAA/NMFS, 1315 East West

Highway, Silver Spring, MD 20910. (301) 713-2325; FAX (301) 713-1043.

August 1998
166

A REEF FISH MONITORING AT THE FLOWER GARDEN

BANKS NATIONAL MARINE SANCTUARY, NORTHWEST

GULF OF MEXICOBASELINE RESULTS

Dr. Christy V. Pattengill-Semmens

Texas A&M University

Department of Biology

ABSTRACT

The reef fish populations of the Flower Garden Banks (FGB) and Stetson Bank (SB) above 30 m

were assessed to establish a database of information for long-term use in the Flower Garden Banks

National Marine Sanctuary (FGBNMS). Data generated from two different visual census methods

collected semi-annually for three years were used to evaluate diurnal fish assemblage structure and

persistence. The suitability of data collected by divers participating in a volunteer fish monitoring

program and the role these data can play in the management of the FGBNMS were also evaluated.

Through the course of this study, 789 visual fish surveys were completed and 177 species were

documented. Forty-five species were new records for the FGBNMS, including a unique color phase

of one species. Similarity in the fish assemblages of the FGB and SB indicated a common species

pooi. Differential recruitment success, settlement success and seasonal attrition occurred between

the banks and most likely were driven by food and habitat availability and the physical environment.

Analyses revealed relatively high levels of stability in species abundance. This dataset provides a

benchmark for future assessments of disturbance and recovery and provides insight into the stability

of an assemblage measured at a large spatial scale. Non-expert volunteers were able to produce

survey results comparable to those of experts. The larger sample size of non-experts increased the

statistical power for many species' estimates of abundance. Volunteer monitoring can provide a

valuable source of data, and also invokes a sense of ownership in the resource.

INTRODUCTION

Detecting changes in a natural community is essential to effective conservation (Spellerberg 1991),

and monitoring data are vital to this effort. Effective policy depends upon objective data, as both a

basis for management decisions and to evaluate the effectiveness of existing regulations (Gittings

et al. 1997). As resource managers and scientists attempt to address the increasing pressures placed

on natural areas, such as coral reefs, monitoring data will be required to assess community health.

In addition, long-term monitoring facilitates the understanding of ecosystem processes and

establishes a baseline that can be used to assess natural and anthropogenic impacts (Spellerberg

1991).

Coral reef ecosystems are complex, as are the inter-relationships between habitat, biotic and abiotic

components. Because of this complexity, components of the system are often used as indicators of
167

changes. Fish abundance and diversity can reflect reef conditions because reef fish are mobile and

many species depend on specific types of food and substrate (Sale 1991; Reese 1993).

Most reef fishes have a life cycle that includes sedentary,reef-associated juveniles and adults, and

a planktonic larval stage that will spend 2-10+ weeks in ocean currents. Therefore, local recruitment

success is affected by reproductive success at other reefs and hydrographic conditions. The level of

local retention varies among sites and usually is minimal. This bipartite life cycle introduces a large amount of natural variation into fish assemblages. Because of this inherent natural variability,

baseline information is necessary to establish the level of natural variation in fish presence and

abundance before one is able to detect significant departures from a previous state, and is necessary

to make reasonable and accurate assessments of community health in the face of natural and

anthropogenic impacts. The level of variation, or persistence, of a system varies among sites, and

has been documented ranging from high (Sale et al. 1994) to minimal (Smith 1978; Gladfelter et al.

1980; Ogden and Ebersole 1981; Grossman et al. 1982). It is especially useful to characterize the

temporal dynamics or variability in undisturbed systems to be able to assess future change.

Traditionally, monitoring natural resources has been done primarily by scientists. As time, financial

resources, and personnel become more limited, the use of trained and experienced volunteers in

monitoring is increasing. In addition, community-based monitoring programs such as the Reef Environmental Education Foundation, Reef Check, Reef Keepers, and Center for Marine Conservation's Underwater Cleanup are gaining momentum. These volunteer programs provide a

large amount of information on a greater geographic and temporal scale that would otherwise be

unavailable, while increasing public awareness about resources and involving the public in science. In addition, participants gain a sense of ownership that is vital to the success of resource

management and protection. Despite these advantages, valid concerns regarding the quality and

application of the data exist.

The fish assemblages of the Flower Garden Banks and Stetson Bank, northwest Gulf of Mexico, were visually censused semi-annually for threeyears in order to evaluate the diurnal fish assemblage

structure and persistence and to establish a baseline of information against which future change can

be measured (Pattengill 1998). In addition, field survey time for this project was often shared with

a volunteer-based fish monitoring program. This summary presents the results from this reef fish monitoring project and discusses the use of fish monitoring as a management tool.

METHODS

Study Area

High-relief banks occur throughout the northwestern Gulf of Mexico (Bright 1977). Three of these banks, the East Flower Garden Bank (EFG), the West Flower Garden Bank (WFG) and Stetson Bank

(SB), make up the Flower Garden Banks National Marine Sanctuary (FGBNMS) and are the focus of this study. The Flower Garden Banks (FGB) are located on the outer continental shelf,

approximately 175 km SSE of Galveston, Texas and are 21 km apart (EFG- 27°54.5N, 93 03oT\T

WFG- 270 52.5!N, 93 °49.O'W). SB is located approximately 112 km SSE of Galveston, Texas(28'09.
168

8'N, 94'17. 9'W). The banks are topographic expressions of seafloor uplift caused by underlying salt

domes and occur as submerged islands of hard substratum surrounded by vast expanses of

terrigenous continental shelf sediments (Bright 1977). All three banks support tropical fauna, but

only the two FGB support coral reefs. Historical fish research at these areas include Boland et al.

(1983), Bright and Pequegnat (1974), Bright et cii. (1974), and Dennis and Bright (1988). A more

complete description of the study area is given in Pattengill (1998).

Data Collection

The fish assemblages of the EFG, WFG and SB were visually censused during six cruises:

September/October 1994, May/June 1995, September/October 1995, May/June 1996, August'

September 1996, and May/June 1997. Two non-destructive visual survey methods were used, the

Stationary Diver Technique (SDT) (Bohnsack and Baimerot 1986) and the Roving Diver Technique

(RDT) (Schmitt and Sullivan 1996). A survey team of six divers experienced in reef fish

identification and assumed to provide equitable results conducted each method. Field identifications

were based on Stokes (1980), Robins et cii. (1986), and Humann and DeLoach (1994).

The SDT method used in this study was modified from Bohnsack and Bannerot (1986). The method

required a diver to remain in the middle of a randomly placed imaginary cylinder with a radius of

6.5 m and a height of approximately 4m. A 6.5m rope, laid on the bottom, was used to help the diver

visualize the cylinder radius. During an initial five-minute period, the diver recorded all fish species

seen in the cylinder. After the initial five-minute period, the stationary diver counted the individual

fishes within the cylinder, working from the bottom to the top of the species list, making one

complete rotation for each species. The only species enumerated during the initial period were those

unlikely to remain in the cylinder (Bohnsack et cii. 1987). The cylinder sites were randomly chosen

using random compass headings and random numbers of kicks, and were assumed to be similar to

the areas of the bank not sampled.

The RDT (Schmitt et cii. 1993; Schmitt and Sullivan 1996) was a roving survey that did not restrict

the diver to a transect or particular area of the reef The roving diver had free swimming range

throughout a dive site and recorded every observed species. Therefore, the number of habitats and

species that could be censused was higher, and information on the large suite of reef-associated

fishes, including some rare and cryptic species was obtained. Dive times varied (though generally

were between 30 and 45 minutes), depending upon the depth and corresponding dive safety limits

At the conclusion of the dive, the diver assigned each species to one of four log scale relative

abundance categories according to the number of individuals seen during the dive (Single [1], Few

[2-10], Many [11-1001, and Abundant [>100]). Both the SDT and RDT methods surveyed visually

identifiable, diurnally active, non-cryptic species that were located on, within, or above the reef

structure.

These banks are relatively deep, and survey time was limited. Analyses on preliminary FOB and SB

survey data were done to determine adequate sample size. These analyses included a plot of

cumulative species recorded versus sample size, sample size optimization analysis (Bros and Cowell
169

1987), and statistical power analysis (Eckblad 1991; Peterman 1990). The results were considered

in light of field-time logistics to detennine a realistic but useable survey design. To acquire an

adequate number of samples, the field survey design required a minimum of two days at each bank,

one day for each method. The research team consisted of six divers, who conducted four SCUBA

dives each day during daylight hours. This reduced biases due to diurnal temporal variation. The

resulting surveys for each method were treated as replicates. The actual number of surveys for each

sample varied due to weather and other factors.

Field survey time was often shared with a volunteer monitoring program the Reef Environmental

Education Foundation (REEF). REEF is a non-profit organization that educates and trains volunteer

sport divers to collect fish census data. Participating volunteers use the RDT to generate surveys that

are scanned into a publicly-accessible database.

Data Analysis

The fish assemblages were described using species composition and species abundance, calculated

based on the data from all six census times pooled. Species abundance was estimated using the

proportional abundance of each species using the SDT data. Species composition and abundance

were also used to compare the fish assemblages of the three banks. Two measures of comparison,

Jaccard's Coefficient (J) and Czekanowski's proportional similarity index (C1 ), were calculated for

the assemblages ofthe three banks. Jaccard's Coefficient (J) (Ludwig and Reynolds 1988), a measure

of percent overlap in the species recorded during SDT surveys at two areas, was calculated as:

J=C/A+B

where A and B were the number of species seen at bank i and bank j, respectively, and C was the

number of species seen in common at both banks. Czekanowski's proportional similarity index (C1)

(Schoener 1968) is ameasure of similarity inthe proportional species composition. It was calculated

as:

1 - 0.5 (IP5 - P351)

where C is the proportional similarity between bank i and j and P and P are the proportion of

species s at bank i andj, respectively. C was calculated from a sub-set of the SDT data. In order to

minimize the effect of including rare species in the calculation of C (Grossman et al. 1982; Rahel

et al, 1984), oniy species that were recorded in 20% or more of surveys from at least one bank were

included in this sub-set. In addition, the sub-set excluded six schooling plauktivores: blue chromis

(Chromis cyanea), brown chromis (Chromis multilineata), creole wrasse (Clepticus parrae),

creolefish (Paranthias furcifer), bonnetmouth (Emmelichthyops atlanlicus) and boga (Inermia

vittata). These species were present in high numbers above the banks, but their presence in SDT

cylinders was inconsistent. When present, their large numbers under-emphasized the proportional

abundance of other species.
170

The persistence in species presence and species abundance was calculated for each bank, and was

calculated as variability over the six census times. Variability in species presence was estimated

using Jaccard's Coefficient, where J was calculated for all pairs ofcensus times (1 vs. 2, 1 vs. 3, 2

vs. 3, etc.). The variability in species abundance was estimated using the Coefficient of Variation

(CV). CV was calculated for each species as:

CV = standard deviation / mean abundance

where a standardized abundance, average number of individuals per SDT survey, was used and CV

was calculated over the six census times.

RESULTS

A total of 789 visual fish surveys were completed during this study (Table 2B.1). A cumulative

species list generated from this study is given in Table 2B.2. The species richness at SB and the FGB

(EFG and WFG combined) were similar but the species composition was not the same (143- SB;

145- FUB; and 177-total, with 1 11 sighted at all three banks). Of the species seen at each bank, only

about half were documented during all six survey trips (61- EFU, 56- WFG and 52- SB), indicating

a pattern of many rare species and a few common ones. Some of the most abundantspecies at all three banks were reef butterflyfish (Chaetodon sedentarius), Spanish hogfish (Bodianus rufus),

bluehead wrasse (Thalassoma bfasciatum), brown chromis (Chromis multilineata), bicolor

damselfish (Ste gastes partitus), creolefish (Paranthi as furcfer), and sharpnose puffer (Canthigaster

rostrata). Species that were in high abundance at the FOB but present in relatively low numbers at

SB were the Creole wrasse (Clepticusparrae), blue chromis (Chromiscyanea), threespot damselfish

(Stegastes planfrons) and queen parrotfish (Scarus vetula). Those that were abundant at SB but

recorded in low numbers at the FGB were the seaweed blenny (Parablennius marmoreus), juvenile

cocoa damselfish (Ste gastes variabilis) and rock hind (Epinephelus adscensionis).

Table 2B. 1. Survey effort. Number of stationary (SDT) and roving (RDT) visual fish surveys

conducted during each cruise to the EFG, WFG and SB.

Cruise

EFG

Stationary Roving

WFG

Stationary Roving

SB

Stationary Roving

Late summer 1994 24 12 21 18 21 20

Earlysummer 1995 14 23 18 23 15 20

Late summer 1995 31 26 26 24 25 29

Earlysummer 1996 17 20 16 22 20 21

Latesummer 1996 26 30 24 28 22 16

Early summer 1997 26 21 26 21 22 21

Total survey effort 138 132 131 136 125 127
171

Table 2B.2. Cumulative species list. Compiled from three years of semi-annual surveys at the

Flower Garden Banks National Marine Sanctuary. Species seen during Roving

(RDT) and Stationary (SDT), as well as those sighted during other dives are listed.

Surveys were conducted in depths of 22-32 m. Species seen at the surface (sfc) and

those seen at night (ngt) are indicated. New documented records for the FGB or SB

are indicated with an asterisk (*) in the right-most column.

SPECIES

Acanthuridae

Acanthurus bahianus

Acanthurus chirurgus

Acanthurus coeruleus

Antennariidae

Histrio histrio

Apogonidae

Apogon affinis

Apogon maculatus

Apogon pseudotnaculatus

Apogon quadrisquarncztus

Aulostomidae

Aulostomus maculatus

Balistidae

Balistes capriscus

Balistes vetula

Canthiderm is sufflamen

Canthidemis maculata

Melichihys niger

Blenrnidae

Hypleurochilus bermudensis

Ophioblennius atlanticus

Parablennius marmoreus

Bothidae

Bothus lunatus

Bothus ocellatus

Congridae

Coner ocean icus

Lobotidae

Lobotes surinamensis

Carangidae

Alectis ciliaris

Caranx bartholomaei

Caranx crysos

COMMON NAME

Surgonfishes

Ocean Surgeonfish

Doctorfish

Blue Tang

Frogfishes

Sargassumfish

Cardinaif'shes

Bigtooth Cardinalfish

Flamefish

Two-Spot Cardinalfish

Sawcheek Cardinalfish

Trumpetfishes

Trumpetfish

Triggerfishes

Gray Triggerfish

Queen Tiggerfish

Ocean Triggerfish

Rough Triggerfish

Black Durgon

Combtooth Blennies

Barred Blenny

Redlip Blenny

Seaweed Blenny

Lefteye Flounders

Peacock Flounder

Eyed Flounder

Conger

Conger Eel

Tripletail

Tripletail

Jacks

African Pompano

Yellow Jack

Blue Runner

x

xx

xx

xngt

sfc

xx

x

x

x

x

xx

x

x

0

*

x x

x x x

x x x

EFG WFG SB FGB FGBNMS

x x x x x

x x x x x

x x x x x

sfc

0

x x x x

0

0 x x
172

Table 2B.2 (continued)

SPECIES COMMON NAME EFG WFG SB FGB FGBNMS

Caranx hippos Cravalle Jack x x x x x

Caranx latus Horse-Eye Jack x x x x x

Caranx lugubris Black Jack x x x x x

Caranx ruber Bar Jack x x x x x

Elagatis bipinnulata Rainbow Runner x x x x x

Selene vomer Lookdown x x Serbia dumerili Greater Amberjack x x x x x Serbia rivoliana Almaco Jack x x x x x Decapterus macarellus Mackerel Scad x x

* Decapterus punctatus Round Scad x x x

* Selar crumenophthalmus Bigeye Send x x

* Trachurus lathami Rough Scad x x x x Carcharhinidae Requeim Sharks

Carcharhinus brevipinna Spinner Shark x x

* Carcharhinusfalciformis Silky Shark x x x

Carcharhinus plumbeus Sandbar Shark x x

Chactondontidae Butterflyfishes

Chaetodon aculeatus Longsnout Butterfly x x x x x

Chaetodon ocellatus Spotfm Butterfly x x x x x

Chaetodon sedentarius Reef Butterfly x x x x x

Chaetodon striatus Banded Butterfly x x x x

Cirrhitidae Hawkfishes

Amblyeirrhituspinos Redspotted Hawkfish x x x x x Clinidac Clinids

Emblemariapandionis Sailfin Blenny x x x x x

Dasyatidae Stingrays

Dasyatis americana Southern Stingray x x x x x Diadontidae Spiny Puffers

Chilomycterus antillaru,n Web Burrfish x 0

Chilomycterus schoepfi Striped Burrfish x 0

Diodori holocanthus Balloonfish x x x x

Diodon hystrix Porcupinefish x x x x x

Echenejdjdae Remoras

Hemiramphus balao Balao sfc sfc x Echeneis naucrates Sharksucker x x x x x Remora remora Remora x x x x

* Ephippidae Spadefisbes

Chaetodipterusfaber Atlantic Spadefish x 0

Exocoetidae Flyingfish

Cypselurus melanurus Atlantic Flyingfish sfc x x
Table 2B.2 (continued)

173

SPECIES COMMON NAME E1G WFG SB FGB FGBNMS

Gobiidae Gobies

Coryphopterus eidolon Pallid Goby x x

* Coryphopterus glaucofraenum Bridled Goby x x x Coryphopterus

punctzectophorus Spotted Goby x 0

Gobioso,na oceanops Neon Goby x x x x x

Gnatholepis rho mpsoni Goldspot Goby x x x x x

loglossus calliuris Blue Goby x x

Priolepis hipoliti Rusty Goby x x Risor ruber Ttisked Goby x x x x

Haemulidae Grunts

Anisotremus surinamensis Black Margate x x Haemulon macrostomzjm Spanish Grunt x 0

Haemulon nelanurum Cottonwick x x x x x Holocentridae Squirrelfishes

Holocentrus adscensionis Squirrelfish x x x x x

Holocentrus bullisi Deepwater Squirrelfish x 0

Holocentrus coruscum Reef Squirrelfish ngt x* Holocentrus marianus Longjaw Squirrelfish x x

[-lolocentrus rufus Longspine Squirrelfish x x x x x

Holocentrus vexillarius Dusky Squirrelfish x x x Myripristisfacobus Blackbar Soldierfish x x x x x

Inermiidae Bonnetmouths

Eminelichthyops atlanticus Bonnetmouth x x x

*

Inermia vittata Boga x x

* Kyphosidae Chubs

Kyphosus sectcztrix/incisor Bermuda/yellow Chub x x x x x Labridae Wrassess

J3odianus puichellus Spotfrn Hogfish x x x x x Bodianus rufus Spanish Hogfish x x x x x Clepticus parrae Creole Wrasse x x x x x

Halichoeres bathyphilus Greenband Wrasse x x

* Halichoeres biviltatus Slippery Dick x x x x x Hcelichoeres cyanocephalus Yellowcheek Wrasse x x

* Halichoeres garnoti Yellowhead Wrasse x x x x x

Halichoeres inacuhpinna Clown Wrasse x x x x x

Halichoeres radiatus Puddingwife x x x x x

Hem ipteronotus splendens Green Razorfish x x x

* Thalassoma bfasciatum Bluehead Wrasse x x x x x
174

Table 2B.2 (continued)

SPECIES COMMON NAME EFG WFG SB FGB FGBNMS

Lutjanidae Snappers

Luijanus buccanella Blackfin Snapper x x Lutjanus cyanopterus Cubera Snapper x x

* Lu/janus griseus Grey Snapper x x x x x

Lutjanusjocu Dog Snapper x x x x x

Ocyurus chrysurus Yellowtail Snapper x x x x x

Rhomboplites aurorubens Vermillion Snapper x x

Matacanthidae Tilefishes

Ma/acanthus plum/en Sand Tilefish x x x x x Mobuhdac Mantas

Manta birostnis Atlantic Manta x x x x x Mo hula hypostoina Lesser Devil Ray x x x x

* Mobula teripicanna Sickle-fin Devil Ray x x

* Monacanthidae Filefishes

A/uterus monocerus Unicorn Filefish x 0

A/uterus scriptus Scrawled Filefish x x x x x Cantherhines macrocerus Whitespotted Filefish x x x x x

Cantherhinespullus Orangespotted Filefish x x x x x

Mullidae Goatfishes

lVlulloidichthys martinicus Yellow Goatfish x x x x x

Pseudupeneus maculatus Spotted Goatfish x x x x x Muranidae Morays

Echelycore nigricans Viper Moray x x Gymnothorax rn/liar/s Goldentail Moray x x x x

* Gymnothorcix moninga Spotted Moray x x x x x Gymnothorax vicinus Purplemouth Moray x x x x

* Myliobatidae Eagle Rays

Aetobatus narinari Spotted Eagle Ray x x x x x Opistognathidne Jawfishes

Opistognathus aurfrons Yellowheaded Jawfish x x x x x Orectolobidae Nurse Sharks

Ginglyrnostoma cirnatuin Nurse Shark x x x x x Ostraciontidae Boxfishes

Lactophnys bicaudauis Spotted Trunkfish x x x x

* Lactophrys polygonia Honeycomb Cowfish x x x x

* Lactophrys quadricornis Scrawled Cowfish x x x x x Lactophiys triqueter Smooth Trurikfish x x x x x Lactophrys triqueter Golden Smooth Trunk x x x x

* Pomacanthidae Angelfishes

Centropyge argi Cherubfish x x x x x
Table 2B.2 (continued)

175

SPECIES COMMON NAME EFG WFG SB FGB FGBNMS

Ho/acanthus bermudensis Blue Angelfish x x x x x

Ho/acanthus ciliaris Queen Angelfish x x x x x

Ho/acanthus tricolor Rock Beauty x x x x x

Pomacanthus paru French Angelfish x x x x x

Pomacentridae Damselfishes

Abudefdufsaxatilis Sergeant Major x x x x x

Chromis cyanea Blue Chromis x x x x x Chromis enchrysura Yellowtail Reefish x x x x x

Chromis insolata Sunshinefish x x x x x

Chromis multilineata Brown Chromis x x x x x Chromis scotti Purple Reefish x x x x x Microspathodon chrysurus Yellowtail Damselfish x x x x x Stegastesfuscus Dusky Damselfish x x x x

* Stegastes part it us Bicolor Damsel x x x x x

Slegasles plan (frons Threespot damselfish x x x x x Stegastes variabilis Cocoa Damselfish x x x x x

Priacanthidae Bigeyes

Priacanthus cruentatus Glasseye Snapper x x x x Rachycentridae Cobia

Rachycentron canadum Cobia x 0

Rhincondontidae Whale Shark

Rhincodon typus Whale Shark x x x x Scaridae Parrotfishes

Scarus coelestinus Midnight Parrotfish x x

* Scarus croicensis Striped Parrotfish x x x x Scarus taeniopterus Princess Parrotfish x x x x x Scarus vetula Queen Parrotfish x x x x x

Sparisoma atomarium Greenbiotch Parrotfish x x x x

* Sparisoma aurofrenatuin Redband Parrotfish x x x x x

Sparisoma viride Stoplight Parrotfish x x x x x

Sciaenidae Drums

Equetus acuininatus Highhat x x x x Equetus lanceolatus Jacknife fish x x x x Equetus punctatus Spotted Drum x x x x x Equetus umbrosus Cubbyu x x Scombridae Mackerels

Acanthocybium solandri Wahoo x 0

Euthynnus alletteratus Little Tuny x x x x x Scomberomorus cavalla King Mackerel x x
176

Table 2B.2 (continued)

SPECIES COMMON NAME EFG WFG SB FGB FGBNMS

Scorpionidae Scorpionfishes

Scorpaenodes caribbaeus Reef Scorpionfish x x Scorpaena plum ieri Spotted Scorpionfish x x x x

Serranidae Sea Basses

Epinephelus cruentatus Graysbe x x x x x Epinephelusfulvus Coney x x x x x

Epinephelus adscensionis Rock Hind x x x x x

Epinephelus guttatus Red 1-lind x x x x x Epinephelus inermis Marbled Grouper x x x x Epinephelus mono Red Grouper x 0

Liopropoma euknines Wrasse Bass x x x x Liopropoma rubre Peppermint Bass x x x x Mycteroperca bonaci Black Grouper x x x x x Serranus phoebe Tattler Bass x x Mycteroperca interstitialis Yellowniouth Grouper x x x x x

Mycteroperca phenax Scamp x x x x

Mycteroperca venenosa Yellowfm Grouper x x x x x Mycteroperca rubra Comb Grouper x x

Mycteroperca tigris Tiger Grouper x x x x Paranthiasfurcfer Creole Fish x x x x x Serranus annulanis Orangeback Bass x x

Serranus tigrinus Harlequin Bass x 0

Sparidae Porgies

Calamus nodosus Knobbed Porgy x x x x x

Sphyraenidae Barracudas

Sphyraena barracuda Great Barracuda x x x x x

Sphyrnidae Hammerheads

Sphyrna lewini Scalloped Hammerhead x x x x x Syngnathidae Pipefishes

Sygnathus pelagicus Sargassum Pipefish sfc x

Synodotidae Lizzardfishes

Synodus intermedius Sand Diver x x x

Synodus saurus Bluestriped Lizzardfish x x x x

* Synodus synodus Red Lizzardfish x x x x x

Tetradontidae Puffers

Canthigaster rostrata Sharpnose Puffer x x x x x

Sphoeroides spengleri Bandtail Puffer x x x x x TOTALS 141 130 148 150 182
Table 2B.3.

177

During the course of this study, 45 species were documented for the first time at the FGB and/or SB

(Table 2B.2). It was assumed that most of these species were not new residents to the banks but

rather were not previously documented due to survey methodology and effort (pers. comm. S.

Gittings, G. Dennis). A few species, however, including the honeycomb cowfish (Lactophrys

polygonia), sergeant major (Abudefdufsaxatilis) and yellowtail snapper (Ocyurus chrysurus) have

established populations since the work of Dennis and Bright in the early 1980s or may currently be

establishing populations. In addition, chance recruitment events at the FGB and SB have led to the

existence of one to a few individuals of species not usually seen at the banks, including midnight

parrotfish (Scarus coelestinus), harlequin bass (Serranus tigrinis) and black margate (Anisotremus

surinamensis). A unique gold color phase of the smooth trunkfish (Lactophrys triqueter) was also

documented during the course of this study (Pattengill, submitted).

Jaccard values indicated highest similarity in species composition between the EFG and WFG, and

that the WFG was slightly more similar to SB than was the EFG (Table 2B.3). A similar trend was

seen when species abundance was used in the comparison (Table 2B.3).

The CV results indicated low temporal variability in the abundance of many species over the six time

periods (Figure 2B.l). Approximately half of the species at each bank had a CV value of less than

1.0. Based on the results of all 155 species, an average (SD) CV of 1.31(0.79), 1.30 (0.81), and 1.41

(0.73) was calculated for the EFG, WFG, and SB, respectively.

During the course of this study 1,222 RDT surveys were completed by REEF participants,

representing approximately 800 survey hours. These data, along with the research team's SDT data

were entered into a database available on the Internet at http://www. reef org. The utility of the nonexpert data were compared with SDT data collected by the research team, and those results are

presented in Pattengill and Semmens (in press).

Similarity analyses. Values in the top of the matrix are Jaccard coefficient values (J),

comparing the species present at the EFG, WFG and SB, based on RDT data. Values

in the bottom of the matrix are proportional similarity values (Cij), comparing the

species abundance of the EFG, WFG and SB. The Cij values were calculated using

SDT abundance data for the top 53 species excluding the schooling planktivores. The

similarity values are based on all surveys conducted during the study.

Bank EFG WFG SB

EFG x 0.85 0.63

WFG 0.86 x 0.64

SB 0.39 0.41 x
178

Figure 2B.1.

DISCUSSION

<0.10-0.39 0,40-0.69 0.70-0.99 1.00-1.29 1.30-1.59 1.60-1.89 1.90-2.19 2.20-2.49

Range of CV

The number of species in each Coefficient of Variation (CV) range. EFG is

represented by the light colored bars, WFG by the dark bars, and SB by the medium

bars. CV was calculated for all species over the six census times, using SDT

abundance.

This study provides the most comprehensive set of information to date on the diurnal fish

assemblages in the high diversity upper zone (18m - 32m) of the FGBNMS. The fish assemblages

of the FGI3 and SB consisted of many rare species and few abundant ones, as is the case in most

tropical systems. As expected, species richness at the three banks was limited compared with other

areas in the tropical western Atlantic. Dennis and Bright (1998) cite three major factors that limit the

number of reef fishes occurring in the northwestern Gulf ofMexico: limited habitat diversity, limited habitat area, and distance from source populations. Recruitment success to the FOB and SB
179

apparently varies among species. The ability of fish larvae to recruit to the banks depends upon

recruitment variability and post-recruitment factors. Recruitment variability is influenced by the

amount of time fishes spend as planktonic larvae, the amount of local larval retention, hydrographic

patterns of the Gulf, and reproductive activities at the FGB, SB and, probablymore importantly, at

distant source areas. Water transport from reef tracts on the Yucatan shelf and off Tampico, Mexico,

into the vicinity of the northwest Gulf of Mexico requires approximately 4 to 9 weeks and rarely

takes less than three weeks (Kirwan et al. 1984; Kelly, pets. comm. as cited in Bright et al. 1991).

Therefore, unless local retention is occurring, species that cannot survive as larvae longer than three

weeks should be unable to recruit to the northwest Gulf. However, the 4,000+ oil and gas platforms

in the Gulf of Mexico may act as "stepping stones" for dispersal. In fact, the recent appearance of

yellowtail snapper (Ocyurus chrysurus) at the FGB in 1997 most likely is a result of this species

"hopping" along the platforms in the eastern side of the Gulf, as reported by recreational fishermen.

This persistence study is one of few conducted on a larger, continuous reef system and in the tropical

western Atlantic region. During the three years of this study, the abundance of many species

exhibited relatively high persistence. While it is clear that the bipartite life cycle of fishes and the

associated recruitment variability affects the fish assemblages at these isolated areas, as evident by

the chance recruits, post-recruitment factors including available food and habitat influence the

resulting FGB and SB systems. Pre and post-recruitment factors interact to maintain relatively stable

assemblages. The low inter-annual variability in physical conditions (S. Gittings, pets. com.) most

likely enhances the stability. The size of the area studied and the minimal anthropo genie pressure

impacting the fish assemblages are likely major contributing factors to the documented stability.

Finally, the species pool available to the FGB and SB is a sub-set of the relatively small tropical

western Atlantic set of species (compared with the Indo-West Pacific), and this undoubtedly leads

to lower levels of natural variability.

In all analyses, the fish assemblages of the EFG and WFG were more similar to each other than

either was to the SB assemblage. This result was expected due to the similarity in habitat between

the two FGB. Several characteristics distinguish SB from the EFG or WFG. The benthic cover and

habitat structure of SB is very different from that found at the FGB. In addition, SB has the greatest

annual temperature range and the lowest winter temperatures among the three banks. Though the

EFG and WFG were more similar to each other than to SB, in all analyses the WFG was consistently

more similar to SB than was the EFG. An obvious similarity between theWFG and SB is the smaller

size of shallow habitat area when compared with the EFG. Considering that these banks are

essentially islands surrounded by much deeper water, the size element of the island biogeography

theory (MacArthur and Wilson 1967) could be an important factor shaping the fish assemblages of

these isolated features (Pattengill et al. 1997). A comparison among the average number of species

and the average number of individual fishes documented per SDT survey supports this idea, with the

smallest being at SB and the largest at the EFG.

The accuracy and reliability of non-expert data needs to be considered before adoption into a

monitoring program. Data presented in Pattengill and Semmens (in press) demonstrate that, given

similar sample size, experts had higher accuracy, but the increased sample effort of non-experts
180

provided data with comparable power. As the REEF program continues to grow, care must be taken

in evaluating the utility of these data. The economy of effort and the large volume of data collected

are this program's greatest advantages. The standardized census method, applied over a wide

geographic range, will provide a consistency in the data collection effort not often available. The

collection of fish sighting information by volunteer sport divers enables the Flower Garden Banks

National Marine Sanctuary to more effectively monitor and protect its resources.

Visual survey methods are routinely used for gathering data on reef fish communities and, because

they are non-extractive, such methods are ideal for marine parks or long-term, repetitive sampling.

Selection of a census method for a long-term monitoring program requires repeatability, effective

use of time, and the provision of valid data that are comparable to studies in other areas. The two

methods employed in this study provide complementary information. The RDT allows a more

complete search than other methods, yielding a more comprehensive species list, while the SDT

provides more quantitative information on a sub-set of species. Results of Spearman correlation

analysis between RDT and SDT abundance ranks were high (0.86, Pattengill 1998), indicating the

RDT abundance estimates for many species are not as crude as one might assume. For the very rare

species and those that are transient or patchy, frequency of sighting might be a more appropriate

measure in monitoring change.

This fish database provides the FGBNMS management with knowledge of the existing conditions.

Without this basic information, evaluating impact, whether natural or anthropogenic, and

documenting change is difficult. An understanding of the level of natural variation in the system,

especially in its current, relatively undisturbed, state, will enhance the ability to evaluate change when detected.

ACKNOWLEDGMENTS

Thanks to my research team G. Bunch, T. Sebastian, C. Sims, B. Semmens, L. Walsh and L. Waylen

for their dedication to this project, and Gary Rinn and Rinn Boats, Inc. for making the field time in

this project possible. The advice and support ofmy advisory committee, D. Owens, S. Gittings, K.

Winemiller, M. Sweet, and J. Eltinge, was greatly appreciated. Funding and support were provided

by the FGBNMS, REEF, Gulf Reef Environmental Action Team (G.R.E.A.T.), National Fish and

Wildlife Foundation (Project #94-201), Texaco Exploration and Production, Inc., Seaspace, Inc.,

Texas A&M Women's Faculty Network, The Gulf of Mexico Foundation, The Flower Gardens

Fund, The International Women's Fishing Association, Gulf Reef Environmental Education

Foundation, Texas Gulf Coast Council of Dive Clubs and Oceanographic Expeditions.

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pp.

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Press, Princeton, New Jersey. 203 pp.

Ogden, J. C. and J. P. Ebersole. 1981. Scale and community structure of coral reef fishes: a longterm study of a large artificial reef. Mar. Ecol. Prog. Ser. 4: 97-103.

Pattengill, C. V. 1998. The structure and persistence of reef fish assemblages of the Flower Garden

Banks National Marine Sanctuary. Dissertation, Texas A&M University, College Station, TX.

Pattengill, C. V. Submitied. Occurrence of a unique color morph in the smooth trunkfish (Lactophrys

triqueter) at the Flower Garden Banks and Stetson Bank, northwest Gulf of Mexico. Bull. Mar.

Sci.

Pattengill, C. V. and B. X. Semmens. In press. Analysis of volunteer-generated data at the Flower

Garden Banks National Marine Sanctuary: How Powerful is it? J Gulf Mex. Sci.

Pattengill, C. V., B. X. Semmens, and S. R. Gittings. 1997. Reef fish trophic structure at the Flower

Garden Banks and Stetson Bank, NW Gulf of Mexico. 8t Tnt. Coral Reef Symp. 1:1023-1028.

Peterman, R. M. 1990. Statistical power analysis can improve fisheries research and management.

Can. J. Fish. Aquat. Sci. 47: 2-15.

Rahel, F. J., J. D. Lyons, and P. A. Cochran. 1984. Stochastic or deterministic regulation of

assemblage structure? It may depend on how the assemblage is defined. Am. Nat. 124: 5 83-589.

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Colloquium on Global Aspects of Coral Reefs: Health, 1-lazards, and History. 5 9-65.

Robins, C. R., G. C. Ray, and 3. Douglass. 1986. Peterson Field Guides-Atlantic Coast Fishes.

Houghton Mifflin, New York, NY. 354 pp.

Sale, P. F. 1991. The Ecology of Fishes on Coral Reefs. Academic Press, Inc., San Diego. 754 pp.

Sale, P. F., J. A. Guy, and W. 3. Steel. 1994. Ecological structure of assemblages of coral reef fishes

on isolated patch reefs. Oecologia. 98: 83-99.
183

Schmitt, E. F., B. X. Semmens, and K. M. Sullivan. 1993. Research applications of volunteer

generated coral reef fish surveys. The Nature Conservancy. Miami, Fl. 15 pp.

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Ecology. 49: 704-726.

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Dr. Christy Paftengill-Semmens received her Bachelor of Science degree in Biology from the

University of Southern California and earned her doctorate from the Department of Biology at Texas

A&M University. Her research interests include reef fish ecology and the use of monitoring in

management. She currently serves as the Scientific Coordinator for the REEF program and NOAA's

National Marine Sanctuary Program.

SHARKS AND RAYS OF STETSON AND THE FLOWER GARDEN BANKS

Mr. Jeff Childs

Department of Wildlife & Fisheries Sciences

Texas A&M University

iNTRODUCTION

Stetson and the Flower Garden Banks are part of a large array of topographic highs rising up from

the continental shelf of the northwestern Gulf of Mexico (Rezak et al, 1985). Topographic highs are

defined as natural or artificial features rising up from the sea floor that provide significant vertical

and structural relief in an otherwise level and homogeneous landscape. These features function as
184

important habitat for a plethora of marine organisms by serving as suitable substrate within the

photic zone for sessile organisms, which in turn support higher trophic assemblages. These

communities consist largely of resident species; however, many wide-ranging species occur

periodically, interacting with resident species. What wide-ranging species utilize topographic highs,

and more importantly, how topographic highs function as habitat to wide-ranging species is virtually

unexplored, particularly elasmobranchs (sharks, skates and rays).

Biological surveys conducted at Stetson and the Flower Garden Banks report 16 elasmobranch

species (Table 2B.4). However, most records are anecdotal or incomplete, and in some cases,

suspicious. Few specimens or photographs are available to confirm identifications of the reported

species, and in most cases, no effort was made to characterize their abundance, size, sex, or habitat

use.

As a result of coastal habitat loss and heavy fishing pressure, many shark populations in the western

Atlantic and Gulf of Mexico are considered by scientists and resource managers to be overexploited

(NMFS 1998). Of the shark species found in Table 2B.4, six are listed as overfished in a report to

Congress (NMFS 1998). Rays and skates are currently not monitored by the National Marine

Fisheries Service, so their population status is unknown, yet both groups are exploited in the western

North Atlantic Ocean.

Recent declines in the abundance of certain wide-ranging elasrnobranchs have stimulated research

on habitat associations and life history strategies of some species. Fisheries biologists have focused

on the utilization of nearshore waters as nursery areas by sharks (e.g. Gruber et al. 1988, Morrissey

& Gruber 1993a, 1993b, Holland et al. 1993); however, similar investigations around topographic

highs on the mid- and outer-continental shelf have not been conducted. Further, little is known

regarding seasonal habitat areas, such as adult winter and summer feeding areas of many wideranging elasmobranchs.

Stetson and the Flower Garden Banks, together with their immediate waters, comprise the Flower

Garden Banks National Marine Sanctuary (FGBNMS). A primary objective ofresource managers

is to conserve natural living resources (e.g., populations, species, communities) that are

anthropogenically exploited or affected by managing human activities. Because the FGBNMS is

used by thousands of recreational divers each year and fished by commercial and recreational

fishermen, sanctuary personnel are challenged to manage activities for multiple use with an

ecosystem perspective. Meanwhile, fisheries biologists and managers are responsible for conserving

fish populations that include sharks, skates, and rays, particularly those populations exploited by

humans. Information regarding elasmobranch habitat use of the FGBNMS is, therefore, useful to

divers, fishers, biologists, and resource managers.

The objectives of this paper are (a) to summarize the taxonomic diversity of elasmobranchs

associated with Stetson and the Flower Garden Banks, and (b) to assess the habitat use of these sites

by select elasmobranch species.
185

Table 2B.4. Elasmobranchs reported at mid-shelf (MSB) and the Flower Garden Banks (FGB) in

the scientific literature. Stetson Bank is classified as a mid-shelf bank, whereas FOB

are classified as outer-shelf banks. National Marine Fisheries Service considers

species denoted with an asterisk (*) as being overfished, in their annual report to

Congress (1998).

Species FGB MSB Platform References Cited

Gin glymostoma

cirratum * 2, 3, 4, 5 2, 4, 5

Rhincodon typus* 4 5

Isurus oxyrinchus 3

Mustelus canis 3

Carcharhinus

falciformis* 1,3,4 4,5 3

1. Bright& Cashman, 1974

Carcharhinus

Ieucas* ' 4 2. Sonnier, Teerling &

Hoese, 1976 Galeocerdo cuvieri* 3 4 5

Rhizoprionodon 3. Boland, Gallaway, Baker

terraenovae 1,5 45 &Lewbel, 1983

Sphyrna Iewini* 3, 4, 5 4 4. Dennis & Bright, 1988

Squatina dumeril 4, 5 5. Rezak, Bright & McGrail,

1985 Pristis sp. 4, 5

Raja olseni 3

Dasyatis americana 2, 3, 4, 5 2, 4, 5 2

Aetobatis narinari 3, 4, 5

Rhinoptera bonasus 3

Manta birostris 1, 3, 4, 5
186

STUDY SITES

Stetson Bank is a mid-shelf bedrock bank (Rezak 1983) composed primarily of soft claystone

(Neumann 1958). The bank is located 174 km south-southwest of Sabine Pass at 28°l0.O'N and

0940 '17. 'W. The bank occupies approximately 4 ha, witha base depth of 48 m and crests at roughly

20 m (Bright & DuBois 1974). Bank margins are defined by areas of high relief with outcropping

structures standing 4.5 m above the surrounding bottom. These structures are sometimes separated

by small "canyon-like" passages. Total relief for Stetson Bank is calculated at 29 m.

The Flower Garden Banks consist of two bedrock banks with carbonate caps occurring near the

continental shelf edge, approximately 198 km due south of Sabine Pass on the Texas - Louisiana

border. Each bank is the product of upward migrating salt diapirs that in turn supports the

northernmost coral reef communities on the North American continental plate. These banks are

similar in origin, general structure, and sediment distribution, but differ in details of structure,

physiography and sedimentology (Rezak 1983).

The East Flower Garden Bank is at 27054 '32 "N latitude and 93036 'W longitude. The bank is pearshaped and covers an area of about 67 km2. Slopes are steep on the east and south sides, but gentle

to the west and north. The shallowest depths of the bank are about 20 m, whereas surrounding water

depths are about 100 m to the west and north and about 120 m on the east and south sides. Total

relief on the bank is about 116 m (Rezak 1983).

The West Flower Garden Bank is 12 km west of the East Flower Garden Bank at latitude

27°52'27"N, longitude 93°48'47"W, and covers about 137 km2. The bank is oval-shaped and

oriented in a northeast-southwest direction. The crest of the bank lies at a depth of approximately

20 m. Surrounding water depths vary from 100 m to the north, to 150 m to the south. Total relief on

the bank is approximately 130 m (Rezak 1983).

SAMPLING & ANALYSIS

Random in situ surveys of elasmobranchs using SCUBA were conducted opportunistically at the

study sites. Surveys were typically limited to depths of 37 m; however, some surveys were conducted

to depths of 62 m. Observations made from surface platforms (boats or offshore platforms) of

elasmobranchs near the sea surface were also documented. These were compiled with records of

underwater observations into a comprehensive catalogue and classified as one of three observation

types: underwater, surface, or aerial.

Biological and ecological data gathered for each record included the animals' identification to the

lowest taxonomic group possible, estimated size and sex, relative abundance, habitatarea, date, time

of day, location, and notes regarding behavior observed. Sizes were reported in 3-ft increments and

later converted to their approximate metric group (i.e., 1-2 m, 2-3 m, etc.). Shark size was reported

as the estimated total length (TL), while batoid size was reported as the estimated "wing-span" or

disc width (DW) of the animal. Sex was determined by the presence or absence of claspers, and
187

reported as male, female, both sexes present, or undetermined. Relative abundance was reported as

the number of conspecifics observed for each record reported.

Species identifications were confirmed from photographic, videographic documentation or

specimens provided by Texas Parks & Wildlife Department biologists, commercial fishermen, and

recreational divers. Records of elasmobranchs were pooled by site and month. Months were grouped

into the following seasons: Winter 1 (December - January), Winter 2 (February - March), Spring

(April-May), Summer 1 (June - July), Summer 2 (August - September), and Autumn ( October -

November).

Many scientists and lay people participated in elasmobranch surveys on various undocumented

cruises to the study sites; therefore, the overall sampling effort was unmeasurable. However, to gain

some perspective regarding the scope of sampling entails examining the principal effort I made to

survey elasmobranchs. I made personal excursions to study sites with the intention of visiting each

study site at least once during each pooled season. From July 1992 through April 1998, I spent 21

days at Stetson Bank and 172 days at the Flower Garden Banks. While it was possible to visit the

Flower Garden Banks at least once during each season, I was unable to visit Stetson Bank during the

Winter 1 season.

TAXONOMIC DIVERSITY

Fourteen species of elasmobranchs were positively identified from surveys conducted in this study.

These species represent three orders (2 shark & 1 batoid), seven families (4 shark & 3 batoid), and

nine genera (5 shark & 4 batoid) (Table 2B.5). One species (Mobula tarapacana) is a new record

for the Gulf of Mexico (Childs 1997), and three species (Carcharhinusperezi, Dasyatis centroura,

and Mobula hypostoma) are rare records for the northwestern Gulf of Mexico. These species are

predicted to occur in the region (Walls 1975, Robins et al. 1986, Hoese & Moore 1977, McEachran

& Fechhelm 1998); however, these are among the first records confirming their presence. Six species

(Carcharhinus obscurus, C. perezi, Carcharhinus plumbeus, D. centroura, M hypostoma and M

tarapacana) are new records to the banks and reefs of the northwestern Gulf of Mexico. Five

unconfirmed species (Carcharhinus brevipinna, Carcharhinus limbatis, Negaprion brevirostris,

Sphyrna mokarran, arid Sphyrna tiburo) are reported from surveys at these sites that are suspect, and

not discussed further herein.

SEASONAL HABITAT USE AND SELECT SPECIES ACCOUNTS

Table 2B.5 summarizes the seasonal occurrence of juvenile and adult elasmobranch species at

Stetson and the Flower Garden Banks from records gathered during this study . Many sharks are

known to segregate spatially and temporally by size and sex, utilizing different bathymetric or

geographic areas (Springer 1940, 1967). Habitat areas are characterized as adult winter and summer

feeding areas, mating areas, and nursery areas (Castro 1987, 1993). Nursery areas may be further

differentiated as primary and secondary nursery areas (Bass 1978, Simpfendorfer & Milward 1993).
Table 2B.5. Seasonal occurrence of juvenile (J) and adult (A) elasmobranch species reported in this studyare s

section of the table. The presence of both juveniles and adults are denoted by JA. Seasonaelasmobranchs at Stetson (ST) and the Flower Garden Banks (FGB) are portrayed in the lower seBlack blocks represent confirmed reports of the species, while grey blocks represent unconfirmed 

Species Gin glyrnostoma cirratum Rhincodon typus Galeocerdo cuvieri Carcharhinus falciformis Carcharhinus obscums Carcharhinus perezi Carcharhinus plumbeus Sphyma lewini Dasyatis americana Dasyatis centroura Aetobatis narinari Mobula hypostoma Mobula tarapacana Manta birostrisElasmobranch Elasmobranch Habitat Use by Life History Stage Common name nurse shark whale shark tiger shark silky shark dusky shark Caribbean reef shark sandbar shark scalloped hammerhead southern stingray roughtair stingray spotted eagle ray lesser devil ray sicklefin devil ray manta ray Habitat Use by Shelf Position Species Gin glymostoma cirratum Rhincodon typus Galeocenio cuvieri Carcharhinus falciformis Carcharhinus obscurus Carcharhinus perezi Carcharhinus plumbeus Sphyma lewini Dasyatis americana Dasyatis centroura etobatis narinari Mobula hypostoma Mobula tarapacana Manta birostris Common Name nurse shark whale shark tiger shark silky shark dusky shark Caiibbean reef shark sandbar shark scalloped hammerhead southern stingray roughtail stingray spotted eagle ray lesser devil ray sickte1n devil ray manta ra Winter I Winter 2 Sprinq Summer I Sum

Dec-Jan Feb-Mar Apr-May Jun-Jul Au

BOTH FOB 

FGB B

Winter I Winter 2 Spring Summer I Sum

Dec-Jan Feb-Mar Apr-May Jun-Jul Au

A 

JA 

J J J J J J 

A A A A 

A A A 

JA 

FOB FOB FOB 

ST 

FOB 

BOTH 

FGB FGB FOB ST FGB BOTH FOB FGB ST FGB FOB ST FOB FGB BOTH BOTH BOTH 

BOTH 

FGB FGB FOB FOB FGB
189

Primary nursery areas are areas where adult female sharks deposit their offspring, whereas secondary

nursery areas are areas wherejuveniles are found before becoming reproductively active andjoining

the adult groups. Juveniles are thought to move seasonally; thus, secondary nursery areas may be

grouped as winter or summer.

Ginglymostoma cirratum: Adult nurse sharks were observed in all seasons except the Winter 1

period when trips to the study sites were rare. Observations of nurse sharkswere rare during the

winter and spring months, while common during the summer months. Whereas this species is not

known to be wide-ranging, it is likely these sites function as year-round habitat for nurse sharks.

Based upon infrequent observations during the winter, nurse sharks presumably inhabit deeper

regions of the banks during the winter months, yet are residents of these features.

Rhincodon typus: Whale sharks were reported in the summer and autumn periods at Stetson and the

Flower Garden Banks when both juvenile and adult sharks were observed. These pelagic

planktivores are wide-ranging, and observations at the study sites are primarily of solitary animals.

However, in two different years, observations were made of aggregations of up to 50 animals in the

waters near the Flower Garden Banks after the annual mass coral spawning event in late summer.

Based upon the data available, it appears that whale sharks utilize a broad area which includes the

study sites as summer feeding habitat.

Galeocerdo cuvieri: Tiger sharks were observed at the Flower Garden Banks during winter months,

and all sightings were adult animals. During this period, it is common to observe more than one

animal in a single dive along the escarpment of a bank. An anecdotal account was reported in July

of an adult tiger shark caught with hook and line at the Flower Garden Banks by recreational

fishermen. It is likely this species occurs in the area throughout the year, although not in the

abundance observed in the winter months. Based upon records gathered in this study, the Flower

Garden Banks function as winter feeding habitat to adult tiger sharks.

C. obscurus and C. perezi: The Flower Garden Banks function as secondary nursery habitat to two

carcharhinid species, the dusky and Caribbean reef sharks. Juveniles of these two species have been

observed primarily on dives conducted during the summer and autumn periods, and specimens of

each species were collected from the Flower Garden Banks. Additional juvenile carcharhinid sharks

were observed during the winter periods at these banks and are best identified as either of these

species.

C. plumbeus: Adult sandbar sharks were observed at the Flower Garden Banks during the Winter

2 period, however not during warnier months of the year. This species was, however, observed at

Stetson Bank during summer months. Due to difficulties in sampling Stetson Bank during the winter

periods, data should not be interpreted to indicate movement between mid-shelf banks such as

Stetson, and outer shelf banks such as the Flower Garden Banks, although this is a reasonable

hypothesis. At present, it is fair to state that sandbar sharks associate with topographic highs, and that

the Flower Garden Banks function as adult winter feeding habitat while Stetson serves as adult

summer feeding habitat.
190

Sphyrna lewini: Scalloped haminerheads were abundant in surveys conducted at the Flower Garden

Banks during the Winter 2 period. Eight robust adult males of this species were documented at the

East Flower Garden Bank in early December, the earliest record of the winter. Observations of this

species basking at the surface during the Winter 2 period are estimated at over 200 adults at each

Flower Garden Bank. Scalloped hammerheads depart the Flower Garden Banks in late March to

early April as water temperatures rise. This species was observed at Stetson Bank during the Winter

2 season; however, few individuals were observed, indicating that this site is not visited by the same

abundance of hammerheads as the Flower Garden Banks. Scalloped hanimerheads were observed

rarely at all sites during the spring, summer and autumn seasons. Data clearly indicates that the

Flower Garden Banks function as adult winter feeding habitat for male scalloped hammerheads.

D. centroura: Small aggregations of three adult roughtail stingrays were infrequently observed at

Stetson Bank and another mid-shelf bank (Sonnier Bank) during the summer season. Little is known

regarding this species, and it is rarely reported in the northwestern Gulf of Mexico. It is possible that

this species visits mid-shelf banks such as Stetson and Sonnier during the summer months as it

migrates over the continental shelf. The migratory pattern of this species in the Gulf of Mexico is

poorly known.

Aetobatis narinari: Spotted eagle rays occur in large aggregations during the winter seasons and

appear to coincide with the scalloped hammerhead migrations. Spotted eagle rays were observed in

early December when adult hammerheads were also observed. All reported spotted eagle rays are

approximately 2 m in width, indicating adults. They have been observed swimming in polarized

schools estimated at 200 individuals per school. These aggregations occur at the Flower Garden

Banks during the Winter 1 & 2 seasons and depart approximately the same time as the scalloped

hammerhead sharks. Solitary individuals are periodically observed at all study sites during spring,

summer, and autumn seasons; however, they are rare based on records collected during these

seasons. The Flower Garden Banks function as adult winter feeding habitat for spotted eagle rays.

Manta birostris: Manta rays are common to these banks and are typically juveniles, although adults

are sometimes observed during the summer months. From data collected, it is accurate to state that

the Flower Garden Banks function as nursery habitat for manta rays in the region; however, their

nursery area may include more than the topographic highs surveyed.

M hypostoma: Adult lesser devil rays were regularly observed at the Flower Garden Banks during

the Spring and Summer 1 seasons in aggregations of up to 22 individuals. Members of both sexes

were documented, often swimming in pairs. The animals appear to migrate from the Flower Garden

Banks in July, and a few individuals have been documented at Stetson Bank in the Summer 2 season.

It appears that this species visits the Flower Garden Banks as part of its annual migratory pattern;

however at this time, I am not certain how these banks function as habitat to the species. It is

possible that these animals mate at these banks, based upon the aggregations and pairing observed;

however, mating behavior has yet to be observed.
191

M tarapacana: Several rare observations of sicklefm devil rays have been made at the Flower

Garden Banks during the Summer 2 period, although not reported in the same year. These records

occur in close timing with the annual mass spawning of corals at the Flower Garden Banks. All devil

rays are pelagic planktivores and thought to be wide-ranging. Previously, this species was reported

to occur off the coast of Venezuela in the western North Atlantic, although thought to occur further

north (Notarbartolo-di-Sciara & Hillyer 1989). Little is known of this species distribution in the

western Atlantic, and how this species uses the Flower Garden Banks can be surmised at best as

opportunistic summer feeding habitat as corals spawn en masse.

CONCLUSIONS

Topographic highs in the northwestern Gulf of Mexico, such as Stetson and the Flower Garden

Banks, are utilized as habitat by a number of wide-ranging elasmobranchs. For some sharks and rays

(tiger, sandbar, and scalloped hammerhead sharks, and spotted eagle rays), the topographic highs

function as adult winter feeding habitat. During the summer, these features serve as adult feeding

habitat to whale sharks and three species of devil rays. The Flower Garden Banks function as nursery

habitat for dusky sharks, Caribbean reef sharks, and manta rays. These sites also support several

resident species that include nurse sharks, Caribbean reef sharks, and manta rays. The Flower Garden

Banks may also function as a mating area for lesser devil rays, although data supporting this

hypothesis is weak.

Because these features serve as important habitat to some wide-ranging elasmobranch species and

some of these species are considered overfished byNMFS (e.g., dusky and sandbar sharks), natural

resource biologists and managers should integrate this information into management plans designed

to conserve elasmobranch populations and ecological assemblages associated with topographic high

ecosystems.

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FISH COMMUNITY STRUCTURE:

MISSISSIPPI/ALABAMA PINNACLE TREND

Dr. Kermeth J. Sulak

Mr. Douglas C. Weaver

Florida Caribbean Science Center

U.S. Geological Survey Biological Resources Division

Dr. Steve W. Ross

North Carolina National Estuarine Research Reserve

Center for Marine Research

[NTRODUCTION

An extensive, high profile, deep reef tract is located on the Mississippi-Alabama outer continental

shelf. This tract, referred to as "The Pinnacles," is one of a number of drowned fossil reef complexes

arising at wide intervals along the shelf edge of the northern Gulf of Mexico along the "40-fathom"

contour. Although shallow reef fish faunas in the Gulf of Mexico have been reasonably well studied,

deep reef faunas have not. Thus, community stmcture and trophic biology for demersal fishes of The

Pinnacles remains poorly known, as do the physical parameters controlling fauna! composition and

species dominance. Currently, it is difficult to draw inferences about the potential vulnerability of

The Pinnacles fauna to human activities on the outer shelf.

The Pinnacles reefs are not actively accreting since rapid light attenuation below 65 m, together with

mid-winter temperatures dipping below 18° c, restricts reef-building corals and algae to sporadic

small colonies. However, these fossil reefs do support a lush fauna of sessile soft corals, black corals,

crinoids and spongestogether forming living habitat for a well-developed fish fauna. These deep

reefs are important as reef fish havens and replenishment zones; i.e., a source of re-population of

more heavily impacted inshore reefs. The Pinnacles probably also serve as important spawning

andlor feeding grounds for key species targeted by sport and commercial fisheries. This area is

potentially vulnerable to the effects of offshore oil development in addition to continuous fishing

pressure.

Our overall research goal is to define demersal fish faunal composition, quantitative community

structure, relative abundance, species dominance, habitat affinities, and trophic structure.

Simultaneously, we will collect physical data about the benthic habitat and water column to define

mechanisms underlying community structure on The Pinnacles. Our study focuses specifically on

numerically dominant resident fishes to define those components dominating food web interactions.
Figure 2B.2. U.S. Geological Survey, BRD station sites occupied during RV Suncoaster Cruise

FCSC 97-0 1, Pinnacles reef tract, Mississippi-Alabama Outer Continental Shelf.

Objectives of this investigation are: (1) to determine taxonomic composition, diversity, and origins

of The Pinnacles fish fauna; (2) to define quantitative community structure; (3) To define

characteristic reef biotopes; and (4) to define species food habits, trophic guilds, and the overall food

web. This report addresses the first three objectives. A companion report by one ofus (Weaver)

addresses the fourth objective.

METHODS

Study Sites. The Pinnacles complex, including out study sites (Figure 2B.2), comprises two linear

series of topographic features that parallel the coastline, 60-80 n. mi. off Mobile Bay. Base depths

of the two tracts are 85 and 110 m, respectively. Reefs are steep-sided and either flat-topped, spiretopped, or ragged topped. They fall into three basic categories of relief: low (< 1 m), medium (1 -5m),

and high (> Sm); and vary from a few meters to a few hundred meters across. We targeted large reefs

in each of the relief categories, since large reefs tend to provide maximum habitat heterogeneity and

fish diversity.

In August 1997, we engaged in an initial BRD OCS-Program that sponsored 12-day ROV

reconnaissance and sampling cruise on RV Suncoaster. A 4-day BRD fish sampling cruise followed

in October 1998 aboard RV Tommy Munro. Additional study specimens were collected incidentally

during MMS-sponsored cruises undertaken by Continental Shelf Associates (CSA). To quantitatively

define community structure during the 1997 cruise, we employed an ROV equipped with a high

195

88° 00'

40

Study

Si

60

80

87° 30'

29°

ii 5mlles 29°

27'

21'

100

Depth in Meters20'

El Angling/Trapping- ROV

Trawling
196

resolution video camera to accomplish timed transects. Videotape analysis was used to identify and

enumerate species and to resolve characteristic biotopes. Trapping, angling, and off-reef trawling

were used during BRD cruises to obtain specimens for ID validation and for stomach content

analysis. Sampling during CSA cruises was accomplished via angling. Sampling methods, including

micro-hook angling were effective for planktivores, microvores, and macrovores.

RESULTS

During the 1997 and 1998 BRD cruises, 118 separate sampling stations were occupied, spanning the

East-West extent of the Mississippi-Alabama pinnacles complex (Figure 2B.2). Individual reefs were

sampled at high intensity for one flat-top pinnacle Figure 2B.3. The fauna and biotopes were

documented via nearly 50 hours of videotape, enabling a rough first-order analysis of faunal

composition, sources of contribution to the fauna, comparative community structure within and

among pinnacles reefs and an empirical classification of dominant reef-fish biotopes. Over 2,400 fish

specimens were collected, representing 150 species, 74 of which are characteristic reef-fish or reefassociated species. Of these, Ca. 700 reef fish specimens have been analyzed for stomach contents.

Resident Caribbean reef fishes are the major component of The Pinnacles fauna. Prominent taxa

include 15 species of serranids, 3 wrasses, 3 pomacanthids, 3 chaetodontids, 3 sparids, 3 scorpaenids,

3 holocentrids, 2 priacanthids, one apogonid, one pomacentrid, and 4 muraenids. A definitive species

list will await verified identifications for preserved specimens and validation of ROV records.

Figure 2B.3. Sampling intensity for one large flat-topped pinnacle study site targeted during BR])

RV Suncoaster Cruise FCSC 97-01.
'97

Fundamentally, however, The Pinnacles support a diverse and abundant tropical reef-fish fauna that

is surprisingly rich, given the latitude and depth, episodic turbidity events from the Mississippi

plume, and the sediment resuspension effects of major storms. Planktivores comprise the dominant

faunal component. Coralivores and herbivores such as scarids and acanthurids are understandably

absent, given the absence of hermatypic corals and their algal symbionts as a food base. Other taxa,

such as balistids and haemulids are very poorly represented on these ahermatypic reefs. Thus, the

fauna might aptly be termed a winnowed Caribbean reef fish fauna, dependent upon a planktonic

food base (versus benthic algal food base as on shallow coral reefs).

A second potentially very important component includes a small number of abundant mobile, schooling, herni-pelagic, predators including the scombrid Euthynnus alletteratus, three species of the

genus Seriola, and the small scad Trachurus lathami. These mobile predators/foragers may play a

major role in structuring fish communities on The Pinnacles reefs. A third component includes shelf

species, associated with reef-top flats, and/or the circum-reef talus apron, including ogcocephalids,

malacanthids, and serranids of the genera Centropristis and Serranus. Such species may use the reef

primarily as a shelter base from which feeding forays can be launched onto adjacent soft substrate.

A fourth faunal component includes fishes from the adjacent upper continental slope, which impinge

on deep reefs, foraging heavily on the reef-top biotope. Included are the codlet Bregmaceros, an

abundant planktivore, along with the boarfishAntigonia, and unidentified myctophids.

Rounding out The Pinnacles fauna, quite surprisingly, are a small group of demersal speciesmore

typically considered residents of soft substrate habitats on the inner shelf and estuary. Included here

are the sciaenids Cynoscion arenarius, Let ostomus xanthurus, and Micropogonias undulatus. These

species were observed by ROy, feeding in large numbers right on the reef surface at night, and were

captured both by angling and baited trap.

Videotape quantification plus food habits data indicate that key trophic guilds on The Pinnacles reefs

include the dominant reef-top planktivore guild, a reef-base micro-benthivore guild, an epifaunal

cropper guild, a demersal macrovore guild, and a pelagic macrovore guild. The food web appears

to be dominated by interaction between the planktivore guild (primarily anthiine species) and two

macrovore guilds (a demersal snapper-grouper-moray guild, and a pelagic amberjack-little tuna

guild). Characteristic members of the planktivore guild include the damselfish Chromis enchrysurus,

and two small streamer-basses, Hemanthias vivanus and Pronotogrammus martinicensis. The diet

of the last species is typical for the guild, predominantly copepods and larval fonns of other taxa.

DISCUSSION

Our deep reef community structure results parallel those of Thresher and Cohn (1986)1, who reported

that planktivorous anthiines dominated the fauna at 80-100 meters at Enewetak Atoll, and that

1 Thresher, R. E. and P. L. Cohn. 1986. Trophic structure, diversity, and abundance of fishes of the deep reef (30-

300 m) at Enewetak, Marshall Islands. Bulletin of Marine Science 38(l):253-272.
198

Table 2B.6. Relative abundance (%) of fishes at reefs of varying topographic profile from BR])

Cruise FCSC 97-01, August 1997. Data derive from ROV videotape analyses.

Parameter = total number of individuals per species divided by total number of fishes

of all species x 100 for a single target reef site representing each category.

piscivores ranked second in importance. However, community structure on deep offshore reefs in

the Gulf of Mexico is much more complicated than this simplistic analogy suggests. Preliminary data

applied to a between-reef comparison reveals that high and medium profile pinnacles are dominated

by the plaiiktivore guild, whereas the micro-benthivore guild predominates on low profile reefs

(Table 2B.6).

Indeed, the area, steepness, rugosity, current complexity, and extent of live cover of individual

pinnacles are all important modifiers of species composition and faunal dominance We propose

seven empirically-defined key reef biotopes for The Pinnacles: reef top (flat), reef crest (rim), reef

slope (wall), reef base, fore-reef patches, circum-reef talus flat, circum-reef sand flat. Thus, withinreef faunal differentiation takes place on a finer spatial scale. For example, on the reef crest biotope,

P. martinicensis predominates among a suite of three key planktivores (Figure 2B.4, upper left). In

contrast, the immediately adjacent reef top biotope is characterized by a suite of two planktivorous

anthjines + one micro-benthivore, with H. vivanus dominating (Figure 2B.4, upper right). On the

circum-reef talus apron biotopes, gobiids, labrids, and priacanthids together dominant the fauna

(Figure 2B.4, lower right).

Species Common Name Percent by Reef Profile Type

Low Medium High

(<im) (1-Sm) (>5m)

Pronotogrammus martinicensis Roughtongue bass 0 86 45

Hemanthius vivivanus Red barbier 0 36

Chromis enchrysurus Yellowtail reeffish 0 10

Pristigenys alta Short bigeye 13 1

Labridae spp. Wrasses 40 1

Serranus phoebe Tattler 40 3 3

Othertaxa 7 11 4

TOTAL 100% 100% 100%
199

Figure 2B.4. Simplistic first-order scheme of community structure among dominant fishes on three

characteristic Pinnacles biotopes.
200

The emerging knowledge of the deep reef fish community structure and diversity provides the

baseline with which to index the health, productivity, and stability of The Pinnacles ecosystem.

Many short-term phenomena are elusive, and difficult to detect and measure; many major events are

equally difficult to assess. Demersal fish communities integrate both, and respond on a time scale

relevant to human interests.

In striking contrast to resilient sessile invertebrates, fishes respond to deteriorating conditions by

moving away. In contrast to the poorly described benthic invertebrate fauna, the fish fauna is

completely known taxonomically and readily assessed in terms of taxonomic diversity and species

dominance. Thus, changes in species richness, abundance, dominance rank order, modal size, size

frequency distribution, and biomass can be precisely determined to assess the health and stability of

the deep reef ecosystem. Analysis of food habits of fishes will further reveal the major energy

pathways controlling community structure and identify areas of vulnerability to human activities on

the outer shelf.

We would urge that important corollary studies be undertaken to define the static physical and

dynamic watermass processes that drive community structure on Pinnacles reefs. It can readily be

hypothesized that pinnacles of some critical minimum relief interrupt laminar currents creating local

turbulence. Such local turbulence is of critical importance to planktivorous fishes. Coupling highresolution 3-D topographic mapping of individual study pinnacles with 3-D acoustic Doppler current

profiling, together with simultaneously coordinated, biotope specific, ROV video-transecting of fish

communities, would provide the physical-hydrological context with which to resolve the local

distribution and abundance of the plankton!planktivore food base that determines community

structure on deep reefs.

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Bass, A.J. 1978. Problems in the studies of sharks in the southwest Indian Ocean. Pp.545-594. In

Sensory Biology of Sharks, Skates and Rays. Office of Naval Research, Dept. of the Navy,

Arlington.

Boland, G.S., B.J. Gallaway, J.S. Baker, & G.S. Lewbel. 1983. Ecological effects on energy

development on reef fish of the Flower Garden Banks. National Marine Fisheries, Galveston,

Texas. Contract No. NA8O-GA-C-00057.

Bright, T. J.& C. Cashman. 1974. Fishes. Pp.339-409. In T. J. Bright & L. H. Pequegnat, eds. Biota

of the West Flower Garden Bank. Gulf Publishing Co., Houston.

Bright, T.J. & R. Dubois. 1974. Stetson Bank Epifauna and groundfishes. Pp.4-3 8. In Bright, T.J.,

W. Pequegnat, R. DuBois, & D. Gettleson. Baseline Survey of Stetson Bank in the Gulf of

Mexico. Oceanography Dept. Texas A&M University, College Station. Report for Signal Oil &

Gas Company.
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Castro, J.I. 1993. The shark nursery of Bulls Bay, South Carolina, with a review of the shark

nurseries of the southeastern coast of the United States. Env. Biol. Fishes 38:37-48.

Castro, J.I. 1987. The position of sharks in marine biological communities. Pp.11-17. In S. Cook,

ed. Sharks, An Inquiry Into Biology, Behavior, Fisheries, and Use. Oregon State University

Extension Service, Corvallis.

Childs, 3. 1997. Range extension of Mobula tarapacana in the northwestern Gulf of Mexico. Gulf

of Mexico Sci. 15:39-40.

Dennis, G.D. & Ti. Bright. 1988. Reef fish assemblages on hard banks in the northwestern Gulf of

Mexico. Bull. Mar. Sd. 43 :280-3 07.

Gruber, S.H., DR. Nelson & J.F. Morrissey. 1988. Pafterns of activity and space utilization of lemon

sharks, Negaprion brevirostris, in a shallow Bahamian lagoon. Bull. Mar. Sci. 43:61-76.

Hoese, HD. & RH. Moore. 1998. Fishes of the Gulf of Mexico, Texas, Louisiana, and Adjacent

Waters. Texas A&M Press, College Station.

Holland, K.N., B.M. Wetherbee, J.D. Peterson, & C.G. Lowe. 1993. Movements and distribution

of hammerhead shark pups on their natal grounds. Copeia 1993: 495-502.

McEachran, J.D. & J.D. Fechhelm. 1998. Fishes of the GulfofMexico. Vol.1. University of Texas

Press, Austin.

Morrissey, J.F. & S.H. Gruber. 1 993a. Home range ofjuvenile lemon sharks, Negaprion brevirostris.

Copeia 1993: 425-434.

Morrissey, J.F. & S.H. Gruber. 1 993b. Habitat selection by juvenile lemon sharks, Negaprion

brevirostris. Env. Biol. Fishes 38:311-319.

Neumann, A.C. 1958. The configuration and sediments of Stetson Bank, Northwestern Gulf of

Mexico. Texas A&M Research Foundation Technical Report, No.58. 58-ST

NMFS. 1998. National Marine Fisheries Service Report to congress on the Status of Fisheries of the

United States.

Notarbartolo-di-Sciara, G. & E.V. Hillyer. 1989. Mobulid rays off Eastern Venezuela

(Chondrichthyes, Mobulidae). Copeia 1989:607-614.

Rezak, R. 1983. Geology of the Flower Garden Banks. Pp.111-140. In Rezak, R., T.J. Bright &

D.W. McGrail, eds. Reefs and banks of the northwestern Gulf of Mexico: their geological,
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biological, and physical dynamics. Final Report. Tech. Rept. No. 83-1-1. U.S. Dept. of the

Interior, Minerals Mgmt. Service, Gulf of Mexico OCS Region, New Orleans, Louisiana.

Rezak, R., T.J. Bright & D.W. McGrail. 1985. Reefs and Banks of the Northwestern Gulf of Mexico,

Their Geological, Biological, and Physical Dynamics. John Wiley & Sons, New York.

Robins, C.R., G.C. Ray & J. Douglass. 1986. A Field Guide to Atlantic Coast Fishes of North

America. Houghton Mifflin Co., Boston.

Simpfendorfer, C.A. & N.E. Milward. 1993. Utilization of a tropical bay as a nursery area by sharks

of the families Carcharhinidae and Sphyrriidae. Env. Biol. Fishes 37:337-345.

Sonnier, F., J. Teerling, & H.D. Hoese. 1976. Observations on the offshore reef and platform fish

fauna of Louisiana. Copeia 1:105-111.

Springer, S. 1940. The sex ratio and seasonal distribution of some Florida sharks. Copeia 1940:188-

194.

Springer S. 1967. Social organization of shark populations. Pp.149-174. In P.W. Gilbert, R.E.

Mathewson & D.P. Rall, eds. Sharks, Rays, and Skates. Johns Hopkins Press, Baltimore.

Walls, J. G. 1975. Fishes of the northern Gulf of Mexico. T.F.H. Publications Inc. Neptune City, NJ.

Dr. Kenneth J. Sulak is a research fish biologist and Chief Scientist in the Anadromous, Estuarine

& Marine studies section at the USGS Florida Caribbean Science Center, Gainesville, FL. He has

a Ph.D. and M.S. from the University of Miami, and a B.A. from Harvard University. Sulak is an

expert in the taxonomy of deep-water fishes, and has over 20 years of experience in sea-going studies

of the life history, conimunity structure, ecology, and zoogeography and taxonomy of demersal

marine fishes. He has participated innumerous oceanographic cruises from the Arctic to the tropics

in the Atlantic and Indian oceans, including four submersible missions on ALViN, JOHNSON-SEALINK, and NR-l. Sulak was formerly Director and Senior Fish Biologist at the Atlantic Reference

Center, Huntsman Marine Science Center, Canada.

Dr. Steve W. Ross is Research Director of the North Carolina National Estuarmne Research Reserve,

Wilmington, NC. He has a Ph.D. from the University of North Carolina. Ross is an expert in the

taxonomy, life history, and ecology of hard-bottom reef fishes of the Carolinian Fauna! Province and

Gulf of Mexico. He has extensive experience with SCUBA, submersible and ROV census methods

for quantification of demersal reef-dwelling and slope-dwelling fishes. Ross is a veteran of numerous

coastal and oceanographic cruises, including missions on the NEKTON GAMMA and JOHNSONSEA-LINK. He is currently co-authoring a monograph on the marine fish fauna of the Carolinas.
203

Douglas Weaver is a fish biologist at the USGS Florida Caribbean Science Center, Gainesville, FL.

His areas of research interest are the feeding ecology and population dynamics of reef fishes and

landscape ecology of the Gulf of Mexico. He received his M.S. in zoology from the University of

Florida, and is a Ph.D. candidate in the Department of Fisheries and Aquatic Sciences at the

University of Florida. Weaver is a staff intern in the Coastal and Marine Ecology Branch of the

FCSC.

TROPHIC SUBSIDIES IN THE TWILIGHT ZONE: FOOD WEB STRUCTURE

OF DEEP REEF FISHES ALONG THE MISSISSIPPI- ALABAMA

OUTER CONTINENTAL SHELF

Mr. Douglas C. Weaver

Dr. Kenneth J. Sulak

Florida Caribbean Science Center

U.S. Geological Survey - Biological Resources Division

ABSTRACT

Food web structure of fishes was examined in the deep reef community along the MississippiAlabama outer continental shelf Fish communities on high-profile topographic features are

numerically dominated by roughtongue bass, Pronotogrammus martinicensis, and red barbier,

Hemanthias vivanus. Stomach content analysis reveals that calanoid copepods, mollusk/crustacean

larvae and pelagic tunicates dominate the diet of both species, and that these fishes in turn serve as

prey for large reef predators. Seasonal shifts in the diet of planktivores were also evident. Fish eggs

and fish larvae constitute a greater portion of stomach contents in Feb/March samples, and indicate

trophic links to pelagic, soft-bottom, and possibly nearshore primary production (via spawning

aggregations of large, migrating species). Dietary shifts in predatory fishes reveal that pelagic

plankton (including colonial saips) and planktivorous reef fishes form the primary trophic pathways

throughout the year for common fishes in the deep reef community

INTRODUCTION

Feeding habits and food web structure of reef fishes occurring along the Mississippi-Alabama outer

continental shelf were surveyed. Trophic pathways are important to develop an understanding of the

ecological framework in the reef fish community Analysis of food web structure will identifi the

relative importance of resident reef fishes in the diet of large predatory fishes, predator-prey

relationships among fishes and invertebrates, and the role of fishes in supplying nutrients to the

benthic invertebrate community.
204

Detailed studies of the food habits of deep reef fishes have not been reported in the literature, and

few reports of diets of shallow reef fishes in the Gulf of Mexico are available (e.g. Nelson and

Bortone 1996, Weaver 1996). The reef fish, invertebrate, and plant assemblage varies dramatically

with depth, limiting comparisons among shallow and deep reef communities. To identify food habits

of deep reef fishes, developing food web models from the literature would therefore yield an

inaccurate, simplistic view. Diets of marine fishes are known to vary dramatically with body size,

environment, and season, and collection of fishes provides the only method to develop a detailed

description of trophic pathways in the deep reef environment.

MATERIALS AND METHODS

Fishes were collected by hook-and-line angling during four research cruises from August 1997 to

October 1998. A variety of artificial and natural baits were used to sample fishes over a wide range

of body sizes. Specimens were placed on ice and frozen or immediately preserved in 10% buffered

formalin. Fishes were dissected in the laboratory and stomach contents were removed, sorted, and

prey items were identified to the lowest possible taxon. Numerical abundance of each prey taxon

was calculated to estimate relative importance in the diet of each species. Diets of the common reef

fishes were incorporated into a working food web model following the methods of Winemiller

(1990) to identify the dominant trophic pathways among the reef fish community (Figure 2B.5).

Shor

Bite

Pelagic C rustaceans

and Larvae

Vermilion

Snapper

Copepods

Roughtongue Bass &

Red Barbier

polychaetes amphipods

Red

Snapper

Tattler

crabs bivalves &

gastropods

Red

Porgy

W rasses

20 .27 .22

U rc Ii ins Gelatinous

Zoo plank ton

Plankonic Reef Soft Bottom

Position based on relative proportion of prey from each habitat

Figure 2B.5. Preliminary food web model for the deep reef fish community, based on methods

proposed by Winemiller (1990), indicating primary trophic pathways identified from

samples taken during our August 1997 cruise.
205

Table 2B.7. Prey items identified in stomach contents of specimens collected from the

Mississippi-Alabama outer continental shelf. The number of specimens examined

that contained prey is indicated. "X" indicates presence of prey groups in stomach

contents, while "L" indicates presence ofplanktonic larval forms for each prey group,

such as gastropod veligers and shrimp zoeae.

Taxa

Cfl CC0m0

CC0

.<

(0

C)

.Q

Cl) D

0

a. e

cC

'-

Cl) C) >

.

Cl) 0

a.

.2

2

a.

0

Cl)

.'

Cl) a. .ECl) 0

a.

:

.

Cl) 0

a.

a

°0

U) E-. a

Ui

Cl)

'

C) '

D)

u.i

UU)

Batrachoididae-toadfishes

Opsnusprdus(5) X X X X

Carangidae-jacks

Serbia dumerili (4

Serbia fasciata (1)

Serbia rivoliana (1)

X

X

X

X

Holocentridae-squirrelfishes

HQlocentrus adscensionis (3)

Neaniphon marianus (2) X

L

L

X

L X

X

X

Serranidae-sea basses

Centropristis ocyurus (6)

Hemanthias vivants(50)

Pronotogrammus martinicensis (131)

Serranus phoebe (44)

X

X

X

L

L

L

L X

X

X

L

L

X

L

L

L

X

X

X

X

X

X

X

X

X X

X

X

X

Priacanthidaebigeyes

Priacanthu arenatus (15)

Pristigenys alta (8) X L

X

X

X/L

L

X/L

XIL

X

X

X

Apogonidae-carthnalflshes

Apogon pseudomaculatus (4) XIL L

Malacanthidae-tilefishes

Caulo/ati/us ch,ysops (2)

Malacanthus plumieri (7)

X

X

X

X

X

X

X

X X

Lutjanidae-snappers

Lutjanus campechanus (26)

Rhomboplites aumrubens (74) X L

X

X

X

L

X

XIL X X X X

X

X

Sparidae-porgies

Pagrus pagrus (30) X X X X X X

Sciaenidae-drums

Pare ques umbrosus (3)

Pare ques iwamotoi (1)

X X

X

X

X

XIL x Chaetodontidae-buttertlyfishes

Chaetodon aya (1)

C. sedentarius (3) X

L

L

X

PomacentridaeangeIfishes

Holacanthus bermudensis (2) X X X

Labridae-wrasses

Bodianuspuichellus (3)

Decodon pueliaris (2)

Halichoeres bathyphi/us (10)

X

X

X

X

X

X

X

X X

X

X

XIL L xX

x

X

Pomacentrjdae-damselfishes

Chromis enchrysurus (4) X L X/L X
206

Table 2B.8. Feeding guilds of deep reef fishes along the Mississippi-Alabama outer continental

shelf. Determination of feeding guild is based on stomach contents identified in this

study, or from food habits given by Randall (1967).

Feeding Guild: Characteristic Prey Type

Microzooplanktivorecopepods, ostracods, larvaceans, gastropod veligers,

crustacean larvae.

Macrozooplanktivorehyperiid amphipods, shrimp zoeae, stomatopod zoeae, crab

megalopae, fish larvae, saips, squids.

Piscivoresfishes and squids.

Benthic Generalized Carnivoresa variety of mobile prey that may include fishes,

crabs, shrimps, and gastropods.

Benthic Carnivoresprimarily infaunalepifauna including crabs, bivalves,

gastropods, brittle stars, sea urchins, polychaetes.

Epibenthic Browsers/Grazershydrozoans, bryozoans, soft corals, sponges.

Feeding Guild: Reef Fish Taxa

MicrozooplanktivoresChromis enchrysura, Hemanthias vivanus, Paranthias

furcfer, Pronotogrammus martinicensis, Selar crumenophthalmus, Trachurus

lathami.

MacrozooplanktivoresApogon psuedomaculatus, Chaetodon aya, Priacanthus

arenatus, Pristigenys alta, Rhomboplites aurorubens.

PiscjvoresAulostomus maculatus, Fistularia petimba, Lutfanus campechanus,

Mycteroperca microlepis, M phenax, Serbia dumerili, S. fasciata, S. rivoliana.

Benthic Generalized CarnivoresBodianus puichellus, Centropristis ocyurus,

Corniger spinosus, Epinephelusfiavolimbatus, Epinephelus nigritus, Epinephelus

niveatus, Gymnothorax spp., Holocentrus adscensionus, Liopropoma eukrines,

Ophichthus puncticeps, Muraena spp., Opsanus pardus, Malacanthus plumieri,

Neoniphon marianus, Pontinus rathbuni, Rypticus maculatus, Scorpaena dispar,

Serranus phoebe.

Benthic CarnivoresBalistes capriscus, Calamus leucosteus, C. nodosus,

Caulolatilus chrysops, Decodon puellaris, Halichoeres bathyphilus, Pagrus

pagrus, Pare ques iwamotoi, P. umbrosus.

Epibenthic Browsers/GrazersChaetodon sedentarius, Holacanthus bermudensis,

Parablennius marmoreus.
RESULTS

Over 950 individuals of were examined for food habits, with 500 containing prey items. Dietary

patterns of the most common reef fish taxa are presented in this report (Table 2B.7). Feedingguilds

were then identified based on stomach contents (Table 2B.8). The numerically dominant specieson

high profile reefs, P. martinicens!s and H. vivanus, have diets dominated by calanoid copepods,

gastropod larvae and a variety of other pelagic plankton. Benthic feeders include the tattler,

Serrranus phoebe and the greenband wrasse, Halichoeres bathyphilus, Epibenthic browsers include

the bank butterflyfish, Chaetodon sedentarius, and the blue angelfish, Holacanthus bermudensis.

Seasonal shifts in the diet of the dominant reef fish taxa were evident. The diets of H. martinicensis

include a higher proportion of fish eggs and pelagic tunicates during the early spring. Stomach

contents of S. phoebe in the spring collection were 100% small anthiine fishes. Diets ofvermilion

and red snapper in spring samples were dominated by pelagic tunicates, including colonial

pyrosomes.

CONCLUSIONS

Planktivorous anthiine fishes (P. martinicensis and H vivanus) numerically dominate the deep reef

fish community, although resident fishes in this community occupy a variety of feeding guilds. P.

martinicensis and H vivanus in turn become prey for a variety of reef predators, and newly settled

juveniles and young of the year anthiines appear to be an important seasonal component of the diet

for a number of larger reef fishes. A seasonal shift in the diet is evident for planktivores and larger

predatory species. Fish eggs, fish larvae, and pelagic tunicates increase in importance in the diet of

planktivores, and L. campechanus exhibited a diet dominated by colonial pelagic tunicates in winter

months. Trophic pathways among the deep reef community indicate primary links to the pelagic

community, and eggs and larvae of soft-bottom fishes, a variety of invertebrates, and spawning

aggregations of migratory species (such as M microlepis). Ongoing analysis of food web structure

for the deep reef community will further identifr pathways ofenergy flow and trophic links between

hard-bottom reef, soft-bottom and pelagic ecosystems.

REFERENCES

Nelson, B .D. and S .A. Bortone. 1996. Feeding guilds among artificial reef fishes in the northern Gulf

of Mexico. Gulf Mex. Sci. 1996(2): 66-80.

Randall, J.E. 1967. Food habits of reef fishes of the West Indies. Stud. Trop. Oceanogr. 5: 665-847.

Weaver, D.C. 1996. Feeding ecology and ecomorphology of three sea basses (Pisces: Serranidae)

in the northeastern Gulf of Mexico. Unpublished Master's Thesis. University of Florida, Gainesville, FL.

207
208

Winemiller, K.O. 1990. Spatial and temporal variation in tropical fish trophic networks. Ecol.

Monogr. 60(3):331-367.

Douglas Weaver is a fish biologist at the USGS Florida Caribbean Science Center, Gainesville, FL.

His areas of research interest are the trophic ecology and population dynamics of reef fish

communities and landscape ecology in the Gulf of Mexico and Atlantic Ocean. He received his M. S.

in zoology from the University of Florida, and is a Ph.D. candidate in the Department ofFisheries

and Aquatic Sciences at the University of Florida. Weaver is a staff intern in the Coastal and Marine

Ecology Branch of the FCSC.

Dr. Kenneth 3. Sulak is a research fish biologist and Chief Scientist in the Anadromous, Estuarmne

& Marine studies section at the USGS Florida Caribbean Science Center, Gainesville, FL. He has

a Ph.D. and M.S. from the University of Miami, and a B.A. from Harvard University. Sulak is an

expert in the taxonomy of deep-water fishes, and has over 20 years of experience in sea-going studies

of the life history, community structure, ecology, and zoogeography and taxonomy of demersal

marine fishes. He has participated in numerous oceanographic cruises from the Arctic to the tropics

in the Atlantic and Indian oceans, including four submersible missions on ALVIN, JOHNSON-SEALINK, and NR-1. Sulak was formerly Director and Senior Fish Biologist at the Atlantic Reference

Center, Huntsman Marine Science Center, Canada.

STATUS OF THE GULF OF MEXICO RED SNAPPER STOCK:

ANOTHER PERSPECTIVE

Dr. Benny J. Gallaway

LGL Ecological Research Associates, Inc.

INTRODUCTION

The red snapper Lutjanus campechanus stock in the western Gulf of Mexico was recognized by the

Gulf of Mexico Fisheries Management Council (GMFMC) as being severely overfished more than

a decade ago. The GMFMC implemented management measures beginning in the mid 1980s

(Goodyear 1995). The initial action set a 12-in size limit for the recreational fishery while still

allowing the retention of five undersized fish per fisher. The GMFMC took more restrictive actions

in 1990: the size limit was increased to 13 in; a recreational bag limit of seven fish was imposed;

quotas were established for the commercial fisheries; and, an emerging nearshore longline fishery,

which was taking significant numbers of large red snapper, was prohibited. Also in 1990, the

offshore shrimp fishery began widespread compliance with the Turtle Excluder Device (TED)

regulations that had been implemented to protect sea turtles. These devices may have caused an
209

associated reduction in shrimp catch (Renaud et al. 1993) and fish catch, including red snapper (LGL

Ecological Research Associates, Inc. 1997).

These and continued management actions appear to benefit the affected fish stocks. For example,

the recruit index (CPUE of age 1 red snapper in summer, Goodyear 1995, Schrippa and Legault

1997) has steadily increased since the mid I 980s. As of 1996 (the 1995 year class), recruitment

approached a level last seen in the 1970s and early 1980s (Schrippa and Legault 1997). One

exception occurred in 1990, and reflected exceptional abundance of the 1989 year class (Goodyear

1995, Schrippa and Legault 1997). When the annual commercial quotas were first set in the range

of 2- to 3-million lbs in the mid-1980s, they were not filled. In recent years, Total Allowable Catch

(TAC) has been set at 9.12 million lbs. The commercial allocation (4.65 million ibs) has been

reached within a mafter of weeks, and the fishery subsequently closed. Frequently the recreational

allocation (4.47 million ibs) has been exceeded in these same years, but closures have not occurred

because of the time required to estimate recreational landings. In 1997, the National Marine Fisheries

Service (NMFS), for the first time ever, closed the recreational fishery before the end of the year. In

1998, the fishery was closed at the end of September. Estimates of stock level by year and age

(Schrippa and Legault 1997) has shown substantial increases in recent years, especially the portion

of the stock 14 years of age. Age 14, assuming an instantaneous natural mortality rate of 0.10, is

the age when red snapper reach maximum reproductive potential (Goodyear 1995).

Despite the apparent positive effects of management actions, the unweightedtransitional Spawning

Potential Ratio (SPR, Goodyear 1993, 1995) used to index the status of the stock has remained lower

(1-10%, depending on the assumptions used in the estimate) than the 20% overfishing threshold

adopted by the GMFMC. Further, the GMFMC has recently raised the target SPRvalue to 26 to 27%

which supposedly reflects Maximum Sustained Yield (MSY).

The low levels of SPR has caused NMFS and the GMFMC to continue to take draconian

management measures in order to raise SPR to 26% by the year 2032. We believe that this

management target is not appropriate for red snapper for reasons outlinedbelow.

METHODS AND RESULTS

Stock status at present and in the future is based upon projections from an assessment model. There

are three basic steps in the assessment:

Estimates of fishing mortalities for the directed fisheries (on age-2+ fish) and the numberof

fish by age are made using sequential population analysis (SPA) with an extension of the

ADAPT methodology under three assumed natural mortality rates.

A simple cohort analysis, which accepted the number of age-2 fish from step (1), assumed

natural mortality rates forjuveniles and shrimp bycatch estimates, produces fishing mortality

estimates for the age-0 and age-i fish as well as estimates of the number of age-0 fish

(recruits).
210

A stock assessment simulation model (LSIM, described by Goodyear 1989) uses estimates

from steps (1) and (2) to provide transitional spawning potential ratio (SPR) estimates for

the 1984-94 historical record. Assessment of management alternatives for the future (1999

onward) uses the same model but projected recruits are estimated with an assumed Beverton

and Holt stock-recruitment (S-R) function.

The assessment procedure implies a simple life history. A recruit is defined to be an age-0 fish that

can be captured by shrimp trawls. The sole population control (i.e., density dependence) occurs in

the egg to recruit life-stage. All age classes are assumed to exhibit density independent mortalities

and fecundity. As outlined below we have reservations regarding the populationestimates of age-2+

fish, the natural mortality and bycatch estimates ofjuveniles and the stock-recruit relationship being

used to make future projections of SPR. We take particular exception to the underlying assumption

that red snapper has average resilience to fishing pressure as compared to other stocks of finfish. It

is clearly among the most resilient of firifishes.

Results of Habitat Suitability Index (HSI) modeling in combination with estimates of red snapper

residing at platforms and natural habitats yields an estimate of 8 million age-2 red snapper at the

beginning of 1992. This compares to the stock assessment model estimate of 4 million. Our

estimates of bycatch and the age composition of the bycatch suggests bycatch and the age 1 fraction

of that catch has been grossly overestimated by NMFS. Bycatch estimates similar to ours have been

obtained by independent researchers. Conditional survival from the shrimp fishery is indicated from

these results to be more than doubled.

The available stock recruitment data confirm that red snapper is among the most resistant of all

finfishes to fishing pressure. The SPR associated with the extinction level of fishing for the

"average" finfish is 20%. In comparison the same value for red snapper is about 0.5%. Based on a

Beverton-Holt stock-recruit function, red snapper stock size at an SPR of 26% would be on the order

of 2 billion pounds. This is acknowledged by the managers to be in the ridiculous range. It is likely

that density-dependent population controls occur at life stages other than for the eggs to recruit stage

and that a Ricker stock-recruit function would therefore be more reasonable. Using a Ricker function

with the available S-R data suggests that SPRMSY would be 2.8% and that stock size at this level

would be on the order of 310 million pounds. These levels would be obtained in the near future with

no bycatch reduction and a total allowable catch of 9.12 million pounds.

REFERENCES

Goodyear, C. P. 1993. Spawning stock biomass per recruit in fisheries management: foundation and

current use. In: S. J. Smith, J. J. Hunt, and D. Rivard, editors. Risk evaluation and biological

reference points for fisheries management. Canadian Special Publication of Fisheries and

Aquatic Sciences 120: 67-81.
211

Goodyear, C. P. 1995. Red snapper in U.S. waters of the Gulf of Mexico. Southeast Fisheries

Science Center, Miami Laboratory, Coastal Resources Division, Miami, Florida.

Contribution:M]IA-95/96-05.

LGL Ecological Research Associates, Inc. 1997. Summary updatesregarding bycatch issues in the

Gulf of Mexico. Report to Texas Shrimp Association, Inc., Aransas Pass, Texas.

Renaud, M., G. Gitschlag, E. Klima, A. Shah, D. Koi, and J. Nance. 1993. Loss of shrimp by turtle

excluder devices (TEDs) in coastal waters of the United States, North Carolina to Texas: March

1988-August 1990. Fishery Bulletin U.S. 91:129-137.

Schirripa, M. J., and C. M. Legault. 1997. Status of the red snapper in U.S. waters of the Gulf of

Mexico. National Marine Fisheries Service, Southeast Fisheries Science Center, Miami

Laboratory. Contribution MIA-97/98-05.

Dr. Benny J. Gallaway has worked at LGL Ecological Research Associates, Inc. for the past 23 years

and serves as President and Senior Marine Ecologist for the firm. Dr. Gallaway received his Ph.D.

from Texas A&M University and has in excess of 40 publications in the peer-reviewed literature.

He also serves as a Visiting Professor with the graduate faculty of the Department of Wildlife and

Fisheries Sciences, Texas A&M University.
The Need for NOx Controls in the Central

Planning Area

Strategies for Evaluating NOx Control

Options for Future Outer Continental Shelf

Development Projects

Study: The Operation and Maintenance of

Catalytic Converters on Natural Gas Fired

Compressor Engines

The Operation and Maintenance of

Catalytic Converters at Mobile 916-A

Platform

Industry Perspective on the Need for NOx

Controls

SESSION 2C

NITROGEN OXIDES (NO) IMPACTS AND CONTROLS

IN CENTRAL PLANNING AREA

Co-Chairs: Ms. Terry Scholten and Mr. Jedd Sondergard

Date: December 8, 1998

Presentation Author/Affiliation

Ms. Terry Scholten

Minerals Management Service

Gulf of Mexico OCS Region

Ms. Terry Rooney

BP Exploration & Oil, Inc.

Houston, Texas

Mr. Joim Alford

Santa Fe International Corporation

Dallas, Texas

Mr. Christopher Arms

Hunt Engine, Inc.

Harvey, Louisiana

Mr. Ken DeJohn

Mr. Ronnie Kamper

BP Exploration

Mr. Frank Piccolo

Spirit Energy

Mr. Brian E. Shannon

Principal Environmental Scientist

ARCO Technology & Operational Support

213
THE NEED FOR NOx CONTROLS IN THE CENTRAL PLANNING AREA

Ms. Terry Scholten

Minerals Management Service

Gulf of Mexico OCS Region

ABSTRACT

The Offshore and Coastal Dispersion (OCD) model was used to estimate the cumulative onshore

impact from Outer Continental Shelf (OCS) sources located in the Central Planning Area (CPA) of

the Gulf of Mexico. The results indicate that the significance level for nitrogen dioxide (NO2)

established by the Minerals Management Service (MMS) is exceeded along a portion of the

Louisiana coastline. By MMS regulations, if a significance level is exceeded, then best available

control technology (BACT) is required. Several options are available for resolving this issue.

INTRODUCTION

The significance level forNO2 is defined in 30 CFR2SO.303(e) and 30 CFR25O.304©as an onshore

Concentration from OCS sources that equals or exceeds 1 microgram per cubic meter (jig/rn3). In 30

CFR 250.303(j) and 30 CFR 250.304(f) the significance levels are applied to facilities "either

individually or in combination with other facilities in the area."

The OCD model was used to develop estimates of the cumulative projected impacts from future

lease sales. The results of that modeling (MMS 1997) showed a maximum impact of approximately

six times the significance level. This raised the question of whether the actual emissions from OCS

sources were affecting Louisiana's coastline in concentrations above 1 tg/m3.

METHOD

To determine if current actual OCS emissions affecting the Louisiana coastline were above 1 tg/m3,

several modeling runs were made. Because no current emission inventory was available,

extrapolations were made using the 1993 inventory collected for the Gulf of Mexico Air Quality

Study (Systems Applications International et al, 1995). This inventory is typically called the MOAD

or MMS OCS Activity Database (Steiner et al. 1994).

The OCD model was used for this work because the results will be used for a regulatory application,

and OCD is the only dispersion model approved by MMS for this regulatory purpose.

The modeling domain was separated into seven areas to keep the transport distances typically down

to less than 50 km. The seven individual runs for each year were then combined to generate

composite figures (Figures 2C. 1-2C. 3). All three years of meteorological data, 1989, 1990 and 1991,

produced similar results.

215
216

- -g3 -92 -91 -90 - -88

Figure 2C. 1. 1989 Composite modeling results in micrograms per cubic meter

'-4.0

pb

29 --

28

2&

- -93 -92 -91 -90 -89 -88

Figure 2C2. 1990 Composite modeling results in micrograms per cubic meter.
1.0 ! 29 H28

- -94 -93 -92 -91 -90 -89 -88

Figure 2C.3. 1991 Composite modeling results in micrograms per cubic meter.

The MOAD equipment inventory used included only platform equipment and did not include any

drilling, construction, or transportation emissions. Additionally, OCS activities increased, in the

CPA, between 1993 and 1997, when this work was started. Because of these two factors, the MOAD

equipment inventory is expected to under-represent the emissions for the 1997 to 1998 time frame.

It should be noted however, that modeling with just the MOAD equipment inventory still results in

onshore impacts in excess of 1 Lg/m3. The composites (fig 1-3) were generated from modeling runs

using 1.4 times the MOAD equipment inventory. It is assumed that increasing the inventory by 40

percent is a better approximation of the actual emissions than just using the inventory with no

compensation.

CONCLUSION AND DISCUSSION

All modeling scenarios performed for the cumulative analyses resulted in onshore concentrations

above 1 .xg/m3 along portions of the Louisiana coastline. The onshore impacts ranged from below

0.1 .ig/m3, in portions of Cameron parish, Louisiana and Baldwin county, Alabama, to greater than

4 ig/m3, in portions of Lafourche, Jefferson and Plaquemines parishes of Louisiana.

Since the significance level is apparently exceeded, the regulations require installation of BACT to

reduce the onshore impact. Emission controls are costly. In this case, there is a regulatory

requirement for the controls, but there doesn't appear to be a corresponding environmental need for

the controls. The National Ambient Air Quality Standard for NO2 is 100 tg/m3. All of the areas

affected by the OCS emissions are well within (LDEQ 1998 & EPA 1998) that standard.

217
218

Table 2C. 1. Some options for handling the issue.

Rcgutatory

Rcquircinents

Ct

to

Industry

Cost

to

MMS Cemwents

FM1O1IEACT

faei1ine

YES MOD-HIGH LOW YES Operators allowed to

provide mformation to

demonstrate that they are

not significantly affecting

onshore areas.

in all w

facflites

...

PARTIALLY

S

MOD LOW YES Operators allowed to

provide information to

demonstrate that they are

not significantly affecting

onshore areas. <.::. -:-.-.--.-.--.-.. :1. EURTftIR STUDY

.:-.:.. ....-.-- -:-:-:-:-:-:-:---.-.....-..>..;...:.::.::.:.......-.-:---.-.-.-.-:-:.:<... .... d1fftit

mode'

NO

NO

LOW.MOD

MOD

LOWMOD

MOD

MAYBE!

FUTURE

MAYBE!

FUTURE

May eliminate the need for

controls. Requires MMS tc

approve additional

dispersion model.

Unlikely to eliminate the

need for BACT /needed

for accuracy. Currently a

l9992000 inventory is

planned.

new

invtoy

cby MM NO NONE MOD MAYBE!

FUTURE

No funding is currently

planned for this analysis.

A NOx and 03 study is

planned for 2 000-2002.

iy I*dutry

...........

YES

.:::-:-:-:-:-t-.-.-.--....:...>;...:..:.:.:.

MOD-HIGH

....

NONE MAYBE!

FUTURE

Operators allowed to

provide information to

demonstrate that they are

not significantly affecting

onshore areas.

NO NONE LOW NO

3b) sgfkn NO NONE LOW NO

4) ) AION

NO NONE NONE NO
219

This leads to the question of whether the cost for the controls is justified. The MMS is preparing an

environmental assessment to help in evaluating the different alternatives available for handling this

issue. A matrix of the alternatives is shown in Table 2C.1.

REFERENCES

DiCristofaro, D.C., and S.R. Hanna. 1989. OCD: the offshore and coastal dispersion model, volume

I & II, user's guide. Prepared by Sigma Research Corporation for the U.S. Department of the

Interior, Minerals Management Service, Herndon, VA. Report #A085-l.

LDEQ. 1998. Annual Report: 1994-1997 annual data summaries for the six criteria pollutants for

all Louisiana monitoring sites. http://www. deq. state. la. us/oarp/laarmain. htm

Steiner, C. K., M .C. Causley, and M. A. Yocke. 1994. "User's guide: Minerals Management Service

outer continental shelf activity database (MOAD)." OCS Study MMS 94-0000. U.S. Department

of the Interior, Minerals Management Service, Gulf of Mexico OCS Regional Office, New

Orleans, LA. 14 pp.

Systems Applications International, Sonoma Technology, Inc., Earth Tech, Alpine Geophysics, and

A.T. Kearney. 1995. Gulf of Mexico air quality study, final report, volumes I-Ill. OCS Study

MMS 95-0039, 95-0040, and 95-0041. U.S. Department of the Interior, Minerals Management

Service, Gulf of Mexico OCS Region, New Orleans, LA.

U.S. Dept. of the Interior. Minerals Management service. 1997. Gulf of Mexico OCS oil and gas

lease sales 169, 172, 175, 178, and 182: Central Planning Area--final environmental impact

statement. U.S. Dept. of the Interior, Minerals Management Service, Gulf of Mexico OCS

Region, New Orleans, LA. OCS EIS/EA MMS 97-0033.

U.S. Environmental Protection Agency. 1998. Green book, NOx nonattainment State/area/county

report. http://www.epa.gov/oar/oaqps/greenbk/nncs.html. Downloaded 11/16/98. 1 pp.
220

STRATEGIES FOR EVALUATING NOx CONTROL OPTIONS FOR FUTURE

OUTER CONTINENTAL SHELF DEVELOPMENT PROJECTS

Ms. Terry Rooney

BP Exploration & Oil, Inc.

Houston, Texas

Mr. John Alford

Santa Fe International Corporation

Dallas, Texas

Mr. Christopher Arms

Hunt Engine, Inc.

Harvey, Louisiana

OVERVIEW

Clean Air Act Amendments in 1990 mandated a comprehensive review of the impacts on onshore

air quality from Outer Continental Shelf (OCS) operations under the jurisdiction of Minerals

Management Service (MMS). As a result, a number of changes are occurring in the way emissions

are quantified and new facilities permitted. Based on a facility's distance from shore, length of

operation and development plans, MMS has the authority to require control technology be employed

to reduce significant impact from new offshore operations on onshore air quality.

Offshore oil and gas drilling and producing facilities include space, weight and safety concerns not

associated with land based operations. Temporary peaks in emissions rates can occur in the initial

few years of a project while drilling operations are in progress. It is these peaks that are the most

common cause of any potential short term significant impact. In instances where controls may be

required, the operator and contract partners must select control options that achieve worthwhile

emissions reductions within the technological, logistical and economic constraints of the project.

This analysis identifies a range ofNOx reduction strategies for OCS drilling and production facilities

located in the Gulf of Mexico, the most active OCS region. This paper represents an operator's

perspective on achieving a balance among the many important factors to be considered when

selecting a control strategy. Some of these factors are actual emissions reductions, relative costs,

operating ease and dependability.

The heightened awareness of the necessity to regulate and operate "cleaner, cheaper, better" requires

both operators and agencies to work together constructively. The control option selected should be

the one that achieves the greatest reduction that are truly "significant" for the lowest cost.
OFFSHORE EXPLORATION AND PRODUCTION OPERATIONS

Oil and gas exploration and development from the Outer Continental Shelf (OCS) account for 24%

of the natural gas and 14% of oil production in the United States. This translates into significant

resources for the country and revenues for the Federal Government and coastal states. In 1994, the

United States imported more than half of its petroleum needs. OCS leasing and production are one

of the largest sources of funds for the federal government. In 1993 alone, production from over 3,800

offshore platforms provided $2.5 billion to the federal government and coastal states.'

In 1993, about 800 wells were drilled in the Gulf of Mexico OCS. Drilling is either exploratory or

developmental. Exploration drilling is temporary, ranging from a few weeks for shallow depth wells

to up to half a year for deep wells. If exploratory drilling discovers oil and gas reserves that can be

economically developed, a platform will be built and installed within a few years. Development

wells are drilled from the platform. Drilling from the platform can extend over a number of years

depending on the number of wells needed to produce the field.

Production platforms range in size and complexity from single well structures to large, manned oil

platforms with up to 60 wells. For the first few years following installation, a typical large platform

houses both drilling and production equipment. When all wells are drilled and completed, the rig is

removed and onboard production equipment is all that remains. Large platforms can be in place for

15-20 years.

BP Exploration installed its newest platform in 1,300 feet of water 25 miles off the Mississippi

Delta. This platform will process oil and natural gas from 44 wells. For about 18 months, two

drilling rigs will operate simultaneously, one on the platform and one floating rig, located over 4

miles away, above a subsea template. Oil and natural gas from these wells will be produced through

the existing facility installed in 1994. It is this type of operation - a large new development with the

potential for short term emissions peaks from drilling operations - that may require emissions

reductions strategies not normally necessary.

OFFSHORE DEVELOPMENT EMISSION SOURCES

Drilling

The major emission sources from drilling operations are diesel-powered generators that provide

power for the drilling equipment and ship's services. There are commonly three to four engines, each

capable of generating 1,500 - 2,000 horsepower. Only one-half to two-thirds of that power is

normally required, but specific operations like drilling the large volume surface hole and backup

engine support make it essential that this amount of capacity be available.

221

'Minerals Management Service. 1993. Federal Offshore Statistics: 1993, U. S. Department ofthe Interior, Minerals

Management Service, Operations and Safely Management, Office of Statistics and Information, OCS Report MMS 94-

0060.
222

Table 2C.2. Reduction options, effectiveness and costs.

Reduction Method

Conversion to Turbocharging

Convert roots to centrifugal

blowers

Increase compression ratio 18:1

with general engine overhaul

Timing Retardation

Selective Catalytic Conversion - ammonia injection

Low emissions liquid fuel

Power Management with engine

conditioning

% Reduction*

30-60%

20-30%

Slight increase possible.

Offset by reduced fuel

consumption

50 65%

1 5%

engines operating for 2 years;

consumption; NOx emissions

Costs

$1,500,000

>$800,000

$260,000

$10,000

$1,000,000

$1,800,000

$260,000

includes engine overhaul

does not factor in savings from

without controls - 506 tons per * basedon4-22OOHpJvp

possible reductions in fuel

year - 4000 gpd fuel use

Most rigs operating in the Gulf were built over 10 years ago and do not have the latest control

technologies. Most control options will require retrofitting the existing engine design. A retrofit conversion to an existing engine will be very expensive (see Table 2C.2) and less efficient in terms of NOx prevention than a new, low emissions engine The rig will have to be taken out of service to perform the modification, losing those days, and associated revenues, to down time. Since offshore rigs are engineered to maximize the amount of work to be done in tie least amount ofspace, add-on equipment space and location demands will need to be closely evaluated for design feasibility.

Production

Production equipment usually uses natural gas produced onsite to power engines, generators, turbines, and other combustion equipment. Only emergency pumps and generators are fueled by diesel. Gas compressors, which transport natural gas through the pipeline to onshore, are the major source of long term platform NOx emissions. Turbines generate electricityto power the boilers and heaters on most larger platforms. While they produce large amounts of horsepower, the associated NOx levels will tend to be significantly lower than the compressor engines.

New production facilities incorporate emissions reduction technologies such as Waste heat recovery and vapor recovery units. Waste heat cogeneration reduces fuel consumption and associated emissions while it eliminates the cost of another fuel source. Vapor recovery captures lighter hydrocarbons that would otherwise be lost to the atmosphere from low pressure sources. While only cost-effective on new structures, these examples represent improvements being seen on the newer and larger facilities making them more energy efficient than the olderstructures. Control technology

15 - 40%

80%
223

can be more easily and economically incorporated into new installations than added on to those

already in place.

Production facilities are moving into deeper and deeper waters to support new discoveries with the

greatest potential for finding large hydrocarbon reserves. Current technology will allow facilities to

be installed in water depths of 4,000' and more. The maj or challenge to installing deep water

facilities is one of economics rather than technology. The same rigorous space, weight, and safety

concerns which apply to conventional platforms are even more critical to deeper water projects as

the costs are magnified.

CURRENT REGULATORY OVERSIGHT

Responsibility for managing oil and natural gas exploration and production from the OCS rests with

the Minerals Management Service (MMS), an agency within the Department of Interior. The 1990

Clean Air Act Amendments directed the MMS to determine what, if any, significant impact OCS

operations in the central and western Gulf of Mexico had on onshore ozone non-aftainment areas.

Preliminary photochemical modeling results from an August 1993 episode in Houston Texas

documented that virtually no impact from OCS emissions was seen in onshore areas with high ozone

concentrations.2 From the results of this scientific study, MMS will determine if further action is

needed to control OCS sources to reduce onshore ozone.

The study requirement was an opportunity for MMS to evaluate their regulatory process for

managing air emissions in the Gulf. Those regulations are found in 3OCFR 250 Subpart

CPollution Prevention and Control. As a result, MMS is implementing a series of regulatory

reforms to standardize emissions factors, compile air emissions source data and recommend costeffective emissions reductions from the OCS.

Emissions levels for offshore exploration and development operations are outlined in an Air Quality

Review (AQR), a long-standing requirement for both exploration and development plans. The AOR

is the format for calculating project specific emissions. Project details such as length of operations,

horsepower, vessel support and anticipated well test volumes are input to a standardized spreadsheet.

The AQR spreadsheet is designed to use AP-42 and other standard state and industry factors, along

with project parameters, to calculate the operation's potential to emit.

Similar to onshore Prevention of Significant Deterioration (PSD) criteria, MMS is reviewing

development projects with AQR emissions levels greater than 250 tons per year (in any year of

operation) to determine if additional control technology is required. This threshold review is without

regard to whether the facility is within existing allowable exemption levels. It includes even the

temporary operations that will occur as part of the project, such as drilling operations. MMS

2Yocke, Mark A., Steorts, William L., et cii, Minerals Management Service, Photochemical, meteorological, and

emissions modeling results of the Gulf of Mexico air quality study. Paper presented at 14th Information Transfer

Meeting, Minerals Management Service, 15-17 November 1994, New Orleans, LA.
224

regulations define a source as temporary if it occurs for less than three years. Development projects

that are close to shore, within 100 km, that have long term drilling operations, are the instances most

likely to trigger the evaluation of NOx reduction strategies.

NOx REDUCTION OPTIONS

The first application ofaNOx reduction strategy is at the time of the AQR spreadsheet calculations.

Standard spreadsheet factors will calculate emissions based on continuous operations at maximum

horsepower for all equipment. As mentioned earlier, drilling normally uses less than the maximum

horsepower available onsite. Historic fuel consumption rates for rig engines, certified by the drilling

contractor, should be the basis for the AQR emissions calculations, particularly for large, long-term

projects. Neither drilling nor vessel support operations operate at maximum horsepower on a daily

basis. Consequently, the project's potential to emit can be significantly over-estimated by including

emissions that will never occur.

NOx is the pollutant with the greatest potential to exceed the 250 tons per year (tpy) limit. In

combustion, available nitrogen combines with oxygen to form nitrogen oxides, primarily NO and

NO2. These two compounds are commonly referred to as NOx. NOx is a precursor to ozone and is

a criteria pollutant within the Clean Air Act. Methods to reduce NOx emissions therefore must 1)

prevent NOx from being formed or 2) remove the NOx from engine exhaust before its released to

the atmosphere. Tables 2C.2 and 2C.3 summarize NOx control options for diesel engines. These

tables list the range of predicted reductions, costs and other factors which can be advantages and

disadvantages depending on the specifics of a particular project and rig.

Drilling - Diesel Engines

NOx reduction options for diesel engines are broken into four categories for this discussion: major

engine combustion modifications, ignition timing retardation, new technology and power

management.

Major engine combustion modfIcations include turbocharging and blower conversions and

increasing the compression ratio. Each has its own set of factors to be evaluated for the specific

project. Advantages include emissions reductions up to 60%, reduced fuel consumption and

increased horsepower. Disadvantages are the high equipment costs and significant time required to

convert. The time to retrofit can also be considered lost revenues since the rig may not be able to

operate while the conversion is underway.

Timing retardation involves an engine adjustment up to 60. Peak combustion temperature and

thermal NOx formation are reduced. This adjustment is the least cost -and perhaps the most cost

effective option - with NOx reduction of 15 to 40% possible. Down time is avoided and it is

applicable to all types of diesel engines. The range of reduction is very engine-specific. Fuel

consumption will increase 2 to 4% because of decreased engine efficiency.
225

New technology development can also be found for small niche market of diesel-powered engines.

The options discussed here, exhaust after treatment and low emissions liquid fuel may not be

considered new technologies for some applications. Within the unique space, safety and logistical

needs of the offshore operating environment, further evaluation of these options is required.

Exhaust after treatment, commonly referred to as catalytic converters, offer the greatest reductions,

in the range of 80%. In the oxygen rich exhaust of a diesel, only selective catalytic reduction (5CR)

will decrease NOx. 5CR adds not only the bulk and costs of the catalytic converter and reaction

vessel, but also several significant operational concerns.

The rig layout will need to be evaluated to determine if it can satisfy the equipment space

requirements for the reaction vessel and ammonia bulk tanks. The reaction vessel must be close

enough to the engine exhaust to maintain temperatures between 7200 to 8750 for the reaction to

occur.

Rig engines operate at variable loads so provisions must be made to allow ammonia injection rates

to respond to these load changes. If ammonia injection and load rates are out of synchronization, the

exhaust will be either over-treated, with an associated ammonia slip and potential odor, or undertreated with excess NOx resulting. The amount of aqueous ammonia will vary based on the predicted

emissions of the engines. At a minimum, hundreds of gallons of aqueous ammonia must be onboard

at all times. Provisions must be made to provide a continual supply of the liquid ammonia to the

offshore location and to accommodate the vessel and rig space to store the bulk tanks. Safety

concerns associated with lifting these extra loads onto boats and decks are important issues, in

addition to cost considerations. Additional NOx emissions will result from the vessel support

necessary to supply the large volume of aqueous ammonia to the offshore operation.

Low emissions liquid fuel was developed as a standby fuel for interruptible natural gas supplies in

California. It is a virtual drop-in replacement for #2 diesel, the fuel used in all offshore platform and

semisubmersible rigs. When burning this specialty fuel, diesel engine NOx emissions can be similar

to those of natural gas combustion, according to the manufacturer. Actual emission reduction

benefits from burning this fuel may vary considerably based on the type of engine and combustion

temperature. Costs are a major disadvantage, running three times higher than #2 diesel. This is a

significant cost burden when using thousands of gallons of fuel each day.

Power management is an effort to establish a closer relationship between the amount of power

needed to perform the job versus the amount of power available under normal practice. It must be

stressed that safety concerns take precedent and in no way should the concept of power management

be interpreted as compromising the need for available standby power during critical operations.

The key to power management is to reduce all unnecessary loads allowing one engine instead of two,

or two engines instead of three, to do the job. Unnecessary lighting, excess mud pump pressure, too

many mud pumps and excessive tripping rates are the kinds of routine activities that offer the

greatest potential to reduce horsepower. The demand for greater horsepower results in excess engines

being on-line. Two engines each carrying 40% load waste 17% more fuel and emit 35% more NOx
226

than a single engine canying 80% load. Effective power management requires that each engine be

operated in its optimum range. This will reduce overall NOx emissions and fuel consumption.

A feasibility review, involving key onsite rig personnel from both the operator and drilling

contractor, in addition to engine specialists, will be the first step. Current rig operating standards and

specific needs of the upcoming project will determine feasibility and set the criteria for critical

operations that will require 100% spinning reserve. Once critical operations are defined, possible

reduction opportunities will be defined based on current engine condition, associated fuel

consumption and overall power needs.

Production

Production equipment is generally powered by natural gas. A range of control options exist to reduce

NOx from turbines, reciprocating engines, flares and vents. In house research has provideda range

of capital costs for retrofitting production equipment in the 2,000 HP range.

For natural gas fired turbines, selective catalytic reduction and water injection will provide 80%

reductions for capital costs in the order of $1 - 2 million. Turbines emit much lower concentrations

ofNOx than other production equipment, so it is unlikely that controlling these sources will give the

greatest reduction for the least cost. Natural gas engines can be retrofitted with non-selective

catalytic converters and achieve 80% reductions with capital expenditures of up to $100,000 per

engine. There will be annual costs for operation and maintenance, in addition to catalyst replacement

every seven years. Routine, scheduled maintenance of the catalyst bed and a precise air-fuel ratio

are necessary to achieve the desired reduction and extend the life of the catalyst. Engine

modifications will produce similar reductions of 80%, for higher costs, about $150,000 to $750,000

per engine.

Short term peaks in NOx emissions tend to result from drilling operations, the focus of this report.

Eliminating NOx impacts associated with these drilling peaks could involve installing controls on

the permanent production equipment as the most cost effective approach.

Evaluating control options for production equipment involve the same issues as drilling engines

dodetermining the largest emissions and potential reductions. In the cases reviewed for this

discussion, the largest NOx emissions resulted from operation of natural gas compressor engines.

As with the previous discussion of diesel engine controls, a variety of site-specific factors control

the feasibility and actual costs of retrofitting production equipment. Those factors include proximity

to shore, platform space constraints, age and type of equipment and operating and maintenance

schedules. A few other factors, such as economies of scale and variability in natural gas quality could

affect the feasibility and costs of future retrofits.

Offsets

A final reduction strategy to be evaluated is the offset concept. Are there other facilities where NOx

reductions can be achieved more easily and cheaply that will offset the amount of NOx that is
227

considered to be significant from the newoperations? This approach must be pursued cautiously but

should be an available option for those times when reductions are required. Current MMS

regulations address the use of emissions offsets to reduce impacts on onshore. A regulatory program

must be developed to implement this approach.

FACTORS ThFLUENCING CONTROL SELECTION

As listed in Table 2C.3 there are a host of advantages and disadvantages for each control option

mentioned so far. There is no one method that can be prescribed across the board. Each operation

must be evaluated based on its design parameters and limiting factors. A project's feasibility can be

linked to rig availability, date of anticipatedfirst production and a host of other scheduling concerns.

As a result, the best control technology may not be readily apparent. To optimize the solution, set

project objectives and develop a strategy that gives preference to the least-cost control that

accomplishes the objectives.

Selection of the preferred alternative, or combination of a few, requires careful analysis. It's

important to involve the drilling contractor and other equipment manufacturers in a review of

emissions calculations and alternate control options. As with any new technology or equipment, the

best solution to a problem is reached by understanding all the advantages and disadvantages of

various options that may not be readily apparent.

After a careful review of predicted emissions levels is completed and the most accurate potential to

emit has been determined, it is time to prioritize the controi options based on project details and the

factors listed in Table 2C.3. Each of these considerations will be of varying importance depending

on the project's design parameters and its limiting factors. These advantages and disadvantages will

aid in ranking the control options. As the list of options is reviewed the following questions must

be asked:

what percent reduction is possible?

what is the track record for reliability in achieving reduction target?

will the control be easy to operate and maintain?

are there significant space/weight constraints?

are there safety concerns with the equipment or process? how much down time is required

to retrofit?

are there long-term logistical support needs and costs?

what are capital and O&M costs and is it a significant amount compared to the overall

project costs?

are there innovative ways to get the same reductions elsewhere?

what are measuring and monitoring frequency and costs?

is there an option that reduces long term emissions that may not have been considered

because of regulations?

will other solid or liquid wastes be generated when reducing the air emissions?
228

Table 2C.3. Reduction options, advantages disadvantages.

Reduction Method

Conversion to

Turbocharging

Convert roots blowers to

centrifugal blowers

Increase compression

ratio 18:1 with general

engine overhaul

Timing Retardation

Selective Catalytic

Conversion -ammonia

injection

Low emissions liquid fuel

Power Management with

engine conditioning

Advantages

6 12% decrease in fuel consumption

40% increase in horsepower

4 - 8% decrease in fuel consumption

only engines modified

3-5% decrease in fuel consumption

low costs

no down time

significant reductions

significant reductions

drop in replacement for #2 diesel

no down time for modifications

cost savings from reduced fuel usage

Disadvantages

high costs

40 days downtime to convert

should be done in shipyard

* modification to peripheral

equipment

high costs

30 days downtime to convert

should be done along with blower

conversion

may require special bearings

increase fuel consumption by 2 4%

increase engine wear rates

high costs

10 -12 weeks delivery

size of reaction vessel

transport/handling of ammonia

ammonia slip from load changes

unproven technology offshore

high costs

market availability unknown

use to-date as standby fuel only

behavioral changes required

.

Once this exercise is worked through, the choices will become clearer. The hierarchy of options that

develops can be ranked based on project needs. The rationale for a particular choice will be easy to

communicate and support once this simplified cost-benefit analysis is performed.

An over-arching element for making this strategy successful is involvement with MMS as soon as

possible. Their approval of the project is the litmustest that the controls selected do in fact achieve

the balance between environmental protection and project feasibility. There is no substitute for

formal and informal regulatory feedback throughout this evaluation period. Knowing the agency's minimum requirements and areas where flexibility exists provides the framework for designing a

control plan that will meet the needs of the MMS and operator.

CONCLUSIONS

Evaluating NOx emissions in the OCS is becoming more commonplace. Before major changes are

made in the way the offshore industry is regulated, MMS' current strategy should be allowed

sufficient time to determine its effectiveness. That will result in actual impacts being defined by

sound science, and the associated risks being understood, before additional regulatory burdens are
229

unilaterally imposed. Ifthe science concludes that significant risks exists, government and industry

must form a partnership to identify the mostcost-effective ways of obtaining the greatest reductions.

The stakes are high for both government and industry to work together to get it right. "Cleaner,

cheaper, better" means a/I stakeholders charting a course for the best control option that is fit for

purpose. The objectives are clear - continued exploration and development with cost-effective

approaches to managing environmental risks.

Recent legislative initiatives are directing government agencies to assess all costs and benefits of

available regulatory alternatives when deciding whether and how to regulate. Government should

adopt the policy of using incentives, instead of disincentives, to direct the effort. Agencies must

select those approaches that maximize net benefits.

Industry also has a responsibility to incorporate "cleaner, cheaper, better" into project designs. The

need to evaluate NOx controls could happen at any time during a project, whether it be a new

development or a platform that's been in place for years. For all future facilities, operators need to

carefully weigh environmental impacts and controls during facility design to identify emissions and

reduction technologies that are low cost and reliable. Controls designed into a new facility will be

more economical than future retrofits. Production platforms are intended to be in place for decades.

Regulatory changes should be anticipated. Are the emissions high enough that future regulatory

changes could require a retrofit? If so, would it be cheaper to install the cleaner technology now? An

effective pre-project assessment should preclude or minimize the to retrofit because reasonable

control technologies are incorporated into the original design.

The reductions chosen should allow the operator to work within facility and project limitations. To

reach that balance between maximum emission reduction and least cost control technology many

variables must be identified, measured and prioritized.

Operators should pursue innovative approaches that involve the agencies as partners in the decisionmaking, to facilitate a full understanding of the operational factors that may limit or preclude

choices.

An industry reputation for good performance will provide the cornerstone for the new. initiative to

reform current command and control regulations. A clean environment and oil and gas development

are not mutually exclusive. Voluntary application of commercially viable control technology

demonstrates that environmental protection is an important factor in new facility design.

Government's part must be to replace command and control regulationswith regulations that focus

on reducing significant risks.
230

STUDY: THE OPERATION AND MAINTENANCE OF CATALYTIC CONVERTERS

ON NATURAL GAS FIRED COMPRESSOR ENGINES

Mr. Ken DeJohn

Mr. Ronnie Kamper

BP Exploration

VK-989 PLATFORM: BACKGROUND

Production: - Platform rated for 69,000 BPD of oil and 80 MMSCFD of gas

- Currently producing around 58,000 BPD of oil and 75 MMSCFD of gas

Structure: fixed platform in 1,290 feet of water with 10 well subsea template 5 mile tie-back

from 1,900 feet of water

Wells: 27 wells on platform; 7 subsea wells

Platform started up in October 1994

* Platform control system: pneumatic

COMPRESSORS

Original compressors:

Two compressors rated for 15 MMSCFD of gas each

- Started up in 4th quarter of 1994

- Ariel recip compressors equipped with natural gas engines. Waukesha 9390 GSI rated

for 1970 lIP at 1200 RPM.

- Added cat converters in quarter of 1996

New compressor

- Turbine driven centrifugal rated for 35 MMSCFD added in 3' quarter of 1998

- Taurus 60 turbine equipped with Solonox

CATALYTIC CONVERTER RETROFIT

BPX agreed to add catalytic converters to compressor engines when the DODC for Phase 2

subsea template was approved by MMS

Catalytic converters added to 9390 engines in l quarter of 1996

Catalytic converters should achieve NOX reduction to 2 0 gms/bhp/hr

Weekly testing and monthly reporting to the MMS has been done since installation

System included: (well over $100,000 installed)

- Converters with platinum elements replaced silencers

Air/Fuel controller

- Fuel control valve in fuel gas line

- 02 sensors in exhaust lines
- High temp switches upstream and downstream of converters

- Measurement equipment for weekly readings/troubleshooting

PROBLEMS ENCOUNTERED WITH CATALYTIC CONVERTERS

Process stability

- Process gas fluctuations handled by adjusting engine speed and opening compressor

recycle

- Air/fuel control is always in conflict with engine speed controls

Engine not set up for lean burn

- To work properly, air/fuel ratio mustbe below that recommended by Waukesha for a USI

engine. GL engines are set up to run lean. Concerned with damage to GSI engine at lean

ratio.

Ignition controls

- Existing Fairbanks 9000 Magneto Ignition system was changed out with a full electronic

system (Altronic CPU95) ti bettercontrol and troubleshoot system. Tight ignition control

is required to make systems work and prevent backfires. Change-out of ignition system

was around $30,000 and was done in early 1997.

Catalyst durability & design

- Catalyst bed susceptible to high temperature

- Catalyst bed susceptible to backfires

Backfire relief valve could possibly handle

- Catalyst bed susceptible to settlement of bed material - Expensive to change out; cost of rebuild & platform shut-in

LESSONS LEARNED

Catalytic converters cannot be easily retrofitted onto engines not set up for lean burn

Control systems for catalytic converters are not well suited for applications with process

fluctuations

Reliability arid durability of catalyst beds in question

Tight engine control required

Engines must be heavily loaded to achieve reduction

Operations and maintenance of catalytic converters is labor intensive

231
232

THE OPERATION AND MAINTENANCE OF CATALYTIC CONVERTERS AT

MOBILE 916-A PLATFORM

Mr. Frank Piccolo

Spirit Energy

SUMMARY

NOx control by use of catalytic converters works

- 95% reduction

- 365 tons/yr. reduced NOx output

Lessons learned

- Do not run catalytic converter elements in series

- Install delta psi gauge for monitoring elements

Suggestions for improvement

- Reduce testing and reporting to annually

Table 2C.4. Summary cost, Mobile 916 NOx control.

Up Front Costs

Cost & installation of 3 catalytic converters $115,000

Lessons learned 50,000

Emissions tester 15,000

Total $180,0000

Annual Operating Costs

Cleaning $ 8,000

Calibration gas 2,000

Maintenance 3.000

Total $13,000
I

0

FLOW -0 - j

- 0-

L

True onentation ol

easy access catalyst

portal is 45° near

side or any position

3600 around centerline

Dimensions subject to change without nOtiCe

DeNOX Silencer Identilic.atiori is generally by horsepower rating. The lust digits in the model designation

indicate HP. The lollowing one or two digits is nozzle size. Design flexibility allows change in nozzle size

to best fit piping design.

TANDARO:

Gas Sampling Coupling

Temperature Sensor Coupling

Drain Coupling

Support Brackets

OPTIONS;

Stack or elbow outlet

Side inlet I side outlet

Stack for compliance test

wI 2-2° couplings

Stainless steel Construction

DeNOX Silencer can be

applied for oxidation

service and selective

catalytic reduction.

4

Figure 2C.4. DeNOx Silencer specifications.

233

PAJ7NT NO.

STANDARD SPECIFICATIONS

4.OtJ61

Mnr)FL A B C D WEIGHT

DNIS- 503 8 36 3 20 130

DN/S- 1003. 12 48 3 25 145

DN/S- 1754 14 59 4 35 175

OW/S- 2505 18 61 5 35 200

DN/S-3006CP 20 69 6 41 220

ON/S - 3506 20 68 6 41 230

OWlS- 4008 22 79 8 46 420

ON/S - 4508 22 80 8 48 425

DM15- 5008 22 tiu o 30- 425

OW/S- 57510 22 80 8 48 425

DNIS- 60010 24 5 8 48 525

OWlS- 65010 25 91 8 61 540

OW/S- 70010 26 96 10 61 600

OWlS- 75010 27 96 10 61 625

OW/S- 80010 27 96 10 61 625

DM16- 85012 27

28

96

1OZ

12 61 625

780

DM15.- 90012

DN/S-100012 30 103 12 68 850

DN,S-110012 30 iii 12 74 865

DN/S-115012_ 30 112 12 74 865

ON/S-120014 32 113 14 76 875

ONIS-125014 32 114 14 76 1025

DN/s-135014. 116 14 76 1025

34 1025 _DN/S-145014

DWlS-155016 36 119 16 76 1075

DNlS160016 36 120 16 76 1075

DN/S-1750l6 38 127 16 87 1125

ONIS-185018 38 127 18 87 1125

DN/S-195020 40 147 20 101 1250

DN/S-200020 40 148 20 101 1250

DN,S-220020 42 150 20 101 1275
234

Frank Piccolo is a registered professional engineer working as Operations Engineering Advisor - Mobile Area, in Spirit Energy - 76 Lafayette office. Before coming to Spirit Energy 76, Frank worked 14 years with OXY USA Inc. invarious positions as a production engineer, drilling engineer, reservoir engineer, and operations manager. His geographical responsibilities have included GOM

offshore and onshore, West Texas, NewMexico, and California.

INDUSTRY PERSPECTIVE ON THE NEED FOR NOx CONTROLS

Mr. Brian B. Shannon

Principal Enviromnental Scientist

ARCO Technology & Operational Support

INTRODUCTION

These are the comments and perspectives of the Offshore Operators Committee (OOC) regarding

the Minerals Management Service's(MMS - Gulf of Mexico Region) Notice of Intent to Prepare an

Environmental Assessment (EA) for a Notice to Lessees (NTL) to reduce nitrogen oxides emissions in the Central Planning Area (CPA) of the Gulf of Mexico (63 Federal Register 43191 - 43192, 12 August 1998). These comments will also address the subject draft NTL entitled Best Available Control Technology (Nitrogen Oxides).

The OOC is an industry organization of some 100 member and associate member companieswhich collectively account for approximately 95% of Gulf of Mexico oil and gas production. These

comments are made without prejudicing any individual member's right to have or express different views.

DISCUSSION

As stated in the Federal Register notice, "the proposed action to be analyzed in the EA is a NTL to require best available control technology (BACT) for NOx emissions on all facilities in the CPA"

and further "the MMS requests interested parties to submit conmients regarding any information or

issues that should be addressed in the BA... ." The need for the proposed BA and the draft NTL is based upon MMS modeling runs using the Offshore Coastal Dispersion (OCD) Model to determine

potential cumulative NO2 and 502 impacts on onshore areas in the Final Environmental Impact Statement (FEIS) for Gulf of Mexico OCS Oil and Gas Lease Sales 169, 172, 175, 178, and 182 (OCS EIS/EA, MMS 97-0033). The Table on page IV-214, of the subject FEIS, shows only an exceedance (OCS program modeled without onshore contributions and no treatment of Prevention

of Significant Deterioration (PSD) "baseline") of the Class I maximum allowable increase for NO, (annual average of 2.5 micrograms per cubic meter (ug/m3) versus highest predicted contribution of
235

3.61 g/m3). All other averaging periods for NO2 (Class II) and 502 (Class I and II) maximum

allowable increases are significantly greater than the highest modeled contributions.

This is somewhat misleading since MMS regulations, 30 CFR Part 250.3 03(e) - new facilities and

30 CFR Part 250.304(c) - existing facilities, require the installation of BACT if the annual modeling

significance value (1 jig/m3) is exceeded (on a per facility analysis). The annual modeling

significance level for NO2, on a volume per volume concentration basis, is 0.5 32 parts per billion

pb) and the SO2 annual modeling significance level is equivalent to 0.3 82 ppb. These

concentrations are extremely small and are below the lower detection limit of most air quality

analyzers. It is also interesting to note that the Breton Aerometric Monitoring Program (BAMP)

Technical Review Group (TRG), composed of air pollution professionals from both industry and

government, does not believe that the annual NO2 PSD increment has been consumed in the Class

I Breton National Wilderness Area and have focused their research on the 3-hour and 24-hour

increment for SO2.

The OOC is concerned that MMS has used the annual modeling significance level of 1 g/rn3 in an

inappropriate manner. In the Environmental Protection Agency's (EPA's) PSD program, the

modeling significance level is used to determine if a "single" facility's emissions, when modeled

with a screening air dispersion model such as SCREEN3, need to be analyzed with a more refined

model. Exceeding the modeling significance level does not require the application of BACT; it only

requires the permit applicant to conduct an air dispersion analysis with a more refined model, i.e.,

ISCST3, ISCLT3, CALPUFF, etc..., with the inclusion of nearby (50 miles) emitting sources. The

MMS has conducted the subject modeling on a "cumulative" basis, over a domain of 150 kilometers

(km) or 93.2 miles, with the straight-line steady-state, hourly Gaussian OCD plume model. OCD is

limited to dispersion conditions of inert pollutants that occur within 50 km (31.1 miles) of the source

and are well approximated by steady-state meteorological conditions. At best, the use of OCD, over

such a large domain with minimal surface meteorological data from one C-MAN buoy (42007) most

likely an inappropriate surface site to use in the analysis as it is not representative of the entire CPA,

and upper air data from the onshore National Weather Service's Slidell, Louisiana rawinsonde

station, should be considered a screening analysis and should not result in the imposition of BACT.

We have asked MMS to provide us with a copy of the air dispersion modeling so that we could have

a third party peer review conducted on the work; however, we were told that the work is considered

"draft" and cannot be released outside of the MMS. We will only be allowed to comment on the

modeling work performed for the proposed EA. In addition, when we discussedthis modeling with

appropriate MMS personnel to understand if any simulations had been done to better understand the

cause of the impacts, we were told no analyses of any type, other than the cumulative assessment had

been done. Consequently, imposition of any controls may well be a case ofcost-ineffectiveness, as

sources that have no impact onshore might be forced to implement controls under the proposal.

Again, this assumes that the outcome of a significant impact should even be the trigger for BACT,

with which we disagree.

The proposed BACT (NOx) NTL and BA are based on a "cumulative" projection of development

for future OCS lease sales in the CPA. These projected air emissions may be significantly different
236

from what will actually be installed as emission sources. Industry does not want to install NOx

control equipment on existing facilities because of possible future emissions.

Because air dispersion modeling is key to understanding the impact of offshore exploration and

production sources on onshore receptors, we recommend that MMS perform the EA modeling with

the OCD Model and the non steady-state Lagrangian puff model, CALPUFF/CALMET. However,

as part of the recommendation, we note the need to have a much more robust air quality and

meteorological data base than the very minimal one that was used for the OCD modeling. We make

this recommendation from the results of the Breton Aerometric Monitoring Program (BAMP) Phase

I - Task 1 Final Report (Recommendations For Air Quality Dispersion Models and Related

Aerometric Data Sets in Support of the Breton Aerometric Monitoring Program (BAMP)) prepared

by T. W. Tesche and Dennis E McNally, Alpine Geophysics, LLC, 30 April 1998. Meteorological

conditions are not steady-state in the vicinity of the Breton National Wilderness Area; therefore, the

state-of-the-art CALPUFF/CALMET modeling system is more appropriate than OCD. The modeling

work should make use of the aerometric data required by NTL No. 98 - 08, Meteorological Data

Collection (Breton National Wildlife Refuge/Wilderness Area), 10 August 1998.

Operators within 100 km of the BNWA have been funding the BAMP to provide MMS with

"scientifically peer reviewed" data and recommendations to later perform a PSD cumulative

increment consumption analysis for the Federal Land Manager of the BNWA (if this is ultimately

deemed necessary). This approach is far more rational than running a screening model, with suspect

input variables, and then requiring BACT for NOx to be installed on all existing and proposed

sources in the CPA because an extremely small modeling significance level has been exceeded.

Operators need to know that the amount of capital and maintenance expense they will entail for

BACT NOx controls will actually result in the improvement of onshore air quality. There are no NO2

National Ambient Air Quality Standard (NAAQS, annual NO2 100 g/m3 or 53.2 ppb) nonattainment areas along the Gulf coast. Nor does it appear that there are any problems with the

increment being consumed for the Class II areas along the coast. The State agencies (LDEQ, MDEQ,

and ADEM) have not expressed any concern with offshore petroleum production source impacts

onshore. Further, available data from the state of Louisiana has shown that no coastal parishes in the

CPA are non-attainment for the present 1-hour ozone standard, nor likely to become non-attainment

for the new federal 8-hour ozone standard. One option for the BA is to find that, even with the

questionable OCD modeling, that there are no real onshore air quality problems associated with

offshore facilities. Thus, BACT should not be an option until there is a need.

From the preceding comments it should be clear that the OOC believes that the proposed BACT

(NOx) NTL is premature until it can be demonstrated, with refined modeling, that there is a need to

control NOx. Given that, the following comments will address the proposed NTL.

While it is understood that BACT as used by the MMS is not necessarily BACT as defined by the

EPA, the flexible, case-by-case approach is very troublesome to the offshore exploration and

production industry. While some of our member companies have in-house air pollution experts, the

majority do not. These companies will have to rely on contractors to produce an analysis of the

processes, systems, and techniques considered and proposed to achieve the required BACT (NOx)
237

emissions reduction. Industry has historically requested a so-called "level playing field" in regulatory

programs. The case-by-case approach has too much uncertainty in what theRegional Supervisor will

approve as BACT (NOx). Should the need arise for the MMS to participate in the development of

an onshore State Implementation Plan (SIP) for ozone non-attainment, how would the MMS be able

to forecast the amount of offshore NOx reduction with such a flexible approach?

If an operator wishes to perform modeling to demonstrate that the contribution to the onshore

ambient air concentration of NO2 from a proposed or existing OCS facility, in combination with the

contributions from existing facilities in the area, will not exceed the MMS modeling significance

level, where will he get the needed emissions inventory and what radius of sources need to be

included in the modeling? The operator should be able to use the CALPUFF/CALMET modeling

system, rather than relying on OCD.

Because of the flexible approach, the time necessary for existing sources to develop their BACT

analysis, get it approved on an individual basis, and installed by 1 January 2000 is not feasible. There

are only a limited number of contractors, with the necessary expertise, available to perfonn the

BACT analysis or develop an exception request by 1 July 1999.

The proposed NTL verifies the use of engine injection timing retardation of at least 3 degrees

represents BACT for the control of the emission of NOx when using diesel engines. Engine

retardation may not be appropriate in all cases due to decreased power, poorer fuel economy and

throttle response, and increased emissions of volatile organic compounds (VOCs), particulate matter

(PM1Q and PM25), and carbon monoxide (CU).

Although not expressly stated, we assume that the proposed NIL does not apply to mobile sources

such as work boats, crew boats, MODU's, and drill ships under passage, etc...

We assume that the proposed NTL does not apply to emitting sources installed prior to 1980 and

would request similar clarification.

CONCLUSION

The OOC believes that the provisions for determining whether the significance levels have been

exceeded require that MMS separately determine if each new or existing "non-exempt" facility

individually contributes to onshore ambient air concentrations above the significance level. In

accordance with 30 CFR Part 250.303(j) and 30 CFR Part 250.304(f) if projected emissions from

an "exempt" facility will, either individually or in combination with other facilities in the area,

significantly affect the air quality on an onshore area, then the Regional Supervisor shall require the

lessee to submit additional information to determine whether emission control measures are

necessary. The MMS has conducted cumulative UCD modeling on "all" (notjust with other facilities

in the area) "exempt" facilities, in the CPA, and has concluded that NOx BACT needs to be applied

to all existing and future facilities. OOC recommends that MMS perform the EA modeling with the

OCD Model and the non steady-state Lagrangian puff model, CALPUFF/CALMET. This modeling

should be conducted with more robust air emissions and meteorological data. We also suggest that
238

numerous simulations should be done to better understand the cause of the modeled impacts before

requiring all facilities in the CPA to apply NOx J3ACT.

Brian E Shannon is presently employed by ARCO, in Piano, Texas, as a Principal Environmental

Scientist. He has worked for ARCO for the past 19 years and serves as the first Chaimian of the

OOC's Gulf of Mexico Air Quality Subcommittee (OOC GMAQS). He is also presently the Project

Manager of the OOC funded Breton Aerometric Monitoring Program (BAMP) and a former

Technical Review Group member of the MMS's 1995 Gulf of Mexico Air Quality Study (GMAQS).

Brian received his B.S. in physics in 1972 from the University of Minnesota and his M.S. in

environmental science in 1980 from the Florida Institute of Technology.
Geological Controls and Variability in Pore

Pressure in the Deepwater Gulf of Mexico

DeepStar Project: Phase IV Overview

Marine Board Lightering Study

Document Not Submitted

Deepwater Well Control: IADC/OOC

Guidelines

Document Not Submitted

Deepwater Oil Spill Response Challenges

Document Not Submitted

SESSION ID

DEEPWATER OPERATIONS

Chair: Mr. Jim Regg

Co-Chair: Ms. Deborah Cranswick

Date: December 9, 1998

Presentation Author/Affiliation

Dr. Michael A. Smith

Minerals Management Service

Gulf of Mexico OCS Region

Dr. Paul R. Hays

Texaco Inc.

Dr. E. G. (Skip) Ward

Offshore Technology Research Center

Texas A&M University

Mr. Moe Plaisance

Diamond Offshore Drilling

Mr. Dan Allen

Chevron U.S.A.

239
GEOLOGICAL CONTROLS AND VARIABILITY IN PORE PRESSURE

IN THE DEEPWATER GULF OF MEXICO

Dr. Michael A. Smith

Minerals Management Service

Gulf of Mexico OCS Region

INTRODUCTION

In all areas of the world, pressure-related drilling problems are the leading cause for abandoning a

deepwater well before its targeted reservoir depths are reached or for expensive remedial changes

to be required in the drilling and casing programs. This paper discusses geological controls and

trends in the Onset of geopressure in the deepwater Gulf of Mexico, shallow waterfiow from

overpressured sands in the tophole section, and other pressure-related problems unique to deep

water. These topics are the subject of intense current interest with a number ofjoint industry projects

and predictive models now available for MMS and company participation.

As exploration moves into deeper water in the Gulf of Mexico, pore-pressure prediction and the

correct anticipation of overpressured sands becomes more and more critical to the effective

evaluation of federal OCS lease blocks. The number of exploratory wells in more than 1,000 feet of

water has increased by nearly a factor of three in the past five years (Figure 1 D.l). Although 1999

may see a modest decline in deepwater activity, the number of wells in ultradeep water (more than

5,000 feet) will reach an all-time high.

In this study, we look at the occurrence of geopressure in about 80 wells in deep water from Viosca

Knoll to Alaminos Canyon; most of them fairlyrecent wells drilled in more than 2,000 feet of water.

We also analyze shallow waterfiow encounters and trends in these areas. Finally, we discuss the

MMS regulatory approach to geohazard mitigation and how we are working with offshore operators

to contain the significant pressure-related hazards in deep water.

PORE-PRES SURE GRADIENTS

MMS geological reviews of exploration and development plans and applications for permit to drill on Gulf of Mexico OCS leases contain a discussion of possible abnormal pressure zones. Geopressure is the depth at which fluid pressure exceeds normal hydrostatic pressure (Fertl 1976;

Dutta 1987). This onset of abnormal subsurface pressure is defined as the depth in the weilbore

where pore pressures are equivalent to 12.5 pound per gallon (ppg) mud weights. Burial rates,

geothermal gradients, compaction, and diagenetic reactions are the primary factors affecting the

occurrence of geopressure (Law et al. 1998). In deepwater wells, the large seawater colunm causes

greater depths to abnormal pressure, so depths below the mudline (bml) or seafloor were used in this

study in place of vertical subsea depths. Geological factors controlling the deposition of turbidite

systems, sequence stratigraphy, major faults, unconformities, and salt tectonics also affect pore

241
242

Figure 1D.1. Gulf of Mexico deepwater exploratory wells in more than 1000 feet of water.

pressure. In complexly faulted structures, formation pressures maybe compartmentalized and vary

between different sands.

We have analyzed predicted and actual pore pressures, sedimentation rates, and formation

temperatures in the deepwater Gulf of Mexico and prepared trend maps of the occurrence of

geopressures for this province. The wells in this study are located in four deepwater sections that

include from east to west Viosca Knoll, Mississippi Canyon, and Atwater Valley; Green Canyon;

Garden Banks; and East Breaks and Alaminos Canyon. The upper slope (less than 1,000 meters of

water) in Mississippi Canyon has a thicker Pliocene section with a shallower top of geopressure, an

average of 6,522 feet bml, than the deeper water parts of this area. In deeper water, the average top

of geopressure occurs in the Miocene at 9,996 feet bml. In the younger Plio-Pleistocene section to

the west in Green Canyon, Garden Banks, and East Breaks, the average top of geopressure occurs

at 9,137 feet bml. However, in the deeper section in Green Canyon, Garden Banks, and Alaminos

Canyon to the south and southeast, the top of geopressure occurs in the Miocene at an average depth

of 12,389 feet bml. Throughout the deepwater Gulf of Mexico, it appears that older and more

compacted strata have a deeper top of geopressure than occurs in younger strata.
243

The thermal gradient in Mississippi Canyon and Viosca Knoll is higher than that of deepwater areas

to the west, generally more than 1.5 degree F/i 00 feet. In Garden Banks wells the thermal gradient

averages about 1.0 degree F/i 00 feet and in Green Canyon the temperature gradient appears to

increase from 0.8 to 1.3 degree F/i00 feet to the southeast with greater water depths. These

observations suggest that higher thermal gradients may correspond with a deeper top to geopressure.

Below salt, formations can be overpressured due to an effective seal, and the top of subsalt

geopressure generally occurs at greater depths and deeper in the stratigraphic section.

SHALLOW WATERFLOW SANDS

If shallow waterfiow from an overpressured aquifer occurs above the first pressure-containing string,

it can result in a shallow subsurface geohazard that will impact drilling and cementing practices as

well as the setting depth and number of shallow casing points. This shallow hazard may even cause

a change in surface location or the loss of a well. Shallow waterfiow sands were deposited as

continental slope/fan sequences during Upper Pleistocene progradation, the building out ofprodelta

sandy zones. Since 1984, shallow waterfiow occurrences have been reported in about 60 Gulf of

Mexico lease blocks covering 45 oil and gas fields or prospects. With a few exceptions, waterfiow

incidents occur at water depths exceeding 1,700 feet with an average occurrence in 2,830 feet of

water. Waterfiow problem sands typically occur from 950 to 2,000 feet but have been reported as

deep as 3,500 feet below the seafloor. Individual channel-sand units display slumping zones or debris

flows with a chaotic seismic character and, in some cases, tilted and rotated slump blocks. In the

Mississippi Canyon and southern Viosca Knoll Areas, some of the shallowest channel sands can be

identified as part of a particular distributary system such as the old Timbalier Channel, Southwest

Pass Canyon, or Einstein levee/channel system. High sedimentation rates and an impermeable mud

or clay seal from a condensed section are the main factors contributing to overpressures in shallow

waterfiow sands. These sands occur in a number of depositional subbasins that are generally bounded

by salt ridges or walls. However, none of the occurrences are found over tabular salt sills that are

5,000 to 10,000 feet below the sea floor in some areas. This fact may suggest that communication

with the deeper stratigraphic section contributes to abnormal pressures in shallow sands.

The integration of high-resolution multichannel and reprocessed conventional 2-D and 3-D seismic

data for the tophole section, further refined by seismic facies analysis, can identify sand bodies with

moderate or high shallow waterfiow potential. In assessing shallow waterfiow risk, information from

surrounding wells and shallow borehole tests also provides important data for drilling program

design. The MMS Notice to Lessees and Operators (NTL) on shallow geohazards in the Gulf of

Mexico OCS, NTL 83-3, is currently undergoing extensive revisions (Stauffer et al. 1999). The

updated NTL will accommodate the shifting focus of drilling into deeper water and the improved

technology and data now available to mitigate deepwater geohazards such as shallow waterfiow.

Mitigating approaches that have been used in the drilling of shallow water flowareas include drilling

the shallow section as a pilot hole with MWD logging, dowiihole Pressure While Drilling logging,

and monitoring and confirming shallow water flow occurrences with a ROy. Additional casing

strings and quick-setting foam cements, borehole test to 3,000 to 5,000 feet bml before development

drilling, and other geophysical and engineering techniques that are currently under development have
244

also been employed. The loss of integrity, buckling, or collapse of shallow casing strings in

development wells has caused serious economic loss in several cases. Establishing a database or

catalog of known shallow water flow occurrences and the most effective methods for controlling

them will greatly advance the partnership between the MMS and offshore operators in containing

this critical deepwater hazard (Smith 1999).

OVERPRESSURED SANDS IN ULTRADEEP WATER

In the centroid concept, pore pressure in a reservoir sand at the crest of a high-relief overpressured

structure can exceed pore pressure in the bounding shale. The top of a large structure near the

seafloor may contain fluid pressures that are similar to the fracture gradient in adjacent shale

(Traugott 1997). In water depths greater than 5,000 feet, the weight of a mile or more of a drilling

mud colunm is added to hydrostatic pressure at the seafloor and extra casing strings may be required

in shallow formations as pore pressures approach the fracture gradient. These unplanned additional

casing strings may cause the target sands to be unreachable, or the limited welibore size may be

uneconomic. The marine riserless drilling joint industry project, where the riser carrying mud and

cuttings back to the drilling rig is offset from the drilipipe, may overcome this problem and allow

successful drilling of large, shallow structures by the next generation of drillships in water depths

exceeding 10,000 feet. Other innovative casing and diverter systems are under development that may

also contribute the new technologies required for successful exploration in the deepest Gulf of

Mexico leases.

CONCLUSIONS

Many of the serious and costly drilling problems in deep water are related to the pore

pressure/fracture gradient relationship. Other pressure-related hazards, such as shallow waterfiow,

require better predrill identification and quantification of overpressured problem sands. In many Gulf

of Mexico frontier deepwater areas, a lack of offset wells requires better pressure models that

incorporate all available geological data. Operations geologists andgeophysicists in the MMS are

working with deepwater operators to establish databases and methodologies that will improve

industry's success in dealing with deepwater geohazards in the next millenium.

REFERENCES

Dutta, N.C., ed., 1987, Geopressure: Society of Exploration Geophysicists Reprint Series 7.

Fertl, H.W., 1976, Abnormal formation pressures Amsterdam, Elsevier, 382 p.

Law, B .E., G.F. Ulmishek, and V.1. Slavin, 1998, Abnormal pressures in hydrocarbon environments:

American Association of Petroleum Geologists Memoir 70, 264 p.

Smith, M.A., 1999, MMS regulatory approach to shallow water flow mitigation: Proceedings, 1999

International Forum on Shallow Water Flows, League City, Texas.
245

Stauffer, K.E., A. Ahmed, R.C. Kuzela, and M.A. Smith, 1999, Revised MMS regulations on

shallow geohazards in the Gulf of Mexico: Offshore Technology Conference Proceedings Paper

OTC 10728, v. 1, p. 79-81.

Traugott, M., 1997, Pore/fracture pressure determinations in deep water: World Oil, v. 218, no. 8,

p. 68-70.

DEEPSTAR PROJECT: PHASE IV OVERVIEW

Dr. Paul R. Hays

Texaco Inc.

INTRODUCTION

This summary reviews some highlights ofDeep Star Phase IV work ongoing. Presently Deep Star has

22 participants with Unocal most recently joining us in August of 1998. Amerada I-less, among

others, continues to show a strong interest. The participant roster give a good sense that although the

project has a Gulf of Mexico (GOM) focus, much of the technology is generically applicable

worldwide.

AGIP, British Gas, BHP, BP, Petrobras & Elf all have primary interest outside the GOM. However,

in Phase IV of DeepStar, a significant part of our budget is focused on flow assurance issues that

extend well beyond the Gulf of Mexico.

VENDOR PARTICIPATION

We continue to involve the vendor community in the program with about forty presently contributing

and five to ten more likely to join before the end of Phase IV. These members of the vendor and

contracting community seek to evolve their technology and expertise in closer contact with the oil

industry. For a $5,000 fee per phase, these Contributors can attend most meetings and through inkind or contributed studies advance their own technology and benefit the offshore oil community.

MISSION STATEMENT

DeepStar's Mission: "An Industry-Wide Cooperative Effort Focused on Identification and

Development of Economically Viable, Low-Risk Methods to Produce

Hydrocarbons from Deepwater Tracts in the Gulf of Mexico."

Although the project has a Gulf of Mexico focus whenever environmental criteria are involved, a

large number of the project work products are applicable throughout the world. Exceptions are
246

projects such as the Gulf of Mexico GUM focused Environmental Impact Statement for FPSO's and

the GUM current monitoring program through the Yucatan Straight.

HISTORICAL BACKGROUND

The initial DeepStar studies concerned the feasibility of using extended reach sub-sea development

tied back to a shallow water platform. Texaco thought the topics would be of interest to the industry

as a whole, and the company also sought to recoup some of its costs by selling shares in a $550,000

project. Eleven companies, including the Minerals Management Service (MMS), participated in

DeepStar Phase I.

Although DeepStar did start out focusing on a particular production scenario, extended reach sub-sea

tie back to a shallow water platform, the program has diversified and broadened in scope. The

technology being progressed is modular and many of the topics studied such as pipelines or flow

assurance issues are directly applicable to any area in the world.

INCREASED EMPHASIS ON TESTING

In addition to expanding in scope, the DeepStar program has incorporated additional field scale

testing.

We have brought a composite riser from conceptual study to near term field deployment of a 25-ft.

composite riser pup joint. Currently negotiations are underway between ABB Vetco and an oil

company that has expressed a strong interest in deploying this technology in a deepwater (4,000

ft.) drilling application.

Underway since August 1996, the polyester mooring test has been a two-year test of a vertical

mooring line composed of four manufacturers' ropes, deployed in 3,000 ft. water depth and

instrumented for data retrieval. This system was removed November 1998, and plans are underway

to perform extensive post-deployment analysis and testing to increase industry confidence in

polyester mooring.

Field tests on a gas line owned by Kerr-Mcgee in Wyoming allowed us to verify a technique of

removing hydrate plugs by depressurizing only one size of the plug.

In addition to these accomplishments, several projects in Phase IV involve either field scale

deployments or laboratory testing of prototype scale equipment. As an example, we have initiated

testing of an electrically heated pipeline configuration in a fjord offshore Norway. Large gate and

ball valves for subsea manifolds will be tested in a laboratory setting to verify their efficacy. Also,

we are conducting test engineering to develop procedures to drive conductor casing to 1,000 ft depth

to help alleviate problems that arise when trying to set casing strings within a shallow water flow

zone.
PHASE [V PROGRAM

We kicked off Phase IV in January 1998. Phase IV (actually the 5th phase of the program) is a 24-

month program costing $500,000 per participant. Including money not expended in Phase III (which

has been rolled over), the Phase IV budget for DeepStar is about $13,000,000, a record level.

Because participating fees are cumulative, each oil company participating will have spent about

$1,000,000 on this program, for total cash expenditure on the order of $22 million since the

program's inception. Yet our money has brought us far more than $22 million in R&D because we

have leveraged our dollars by working with the vendor community and the federal government. In

addition to the cash expenditure each company makes, it must be recognized that each oil company

sending representatives to the meetings can readily expend man-hour costs equivalent to, or

exceeding the participation fee. These in-kind costs, which result in the education of our personnel,

provide one of the greatest values of participating in DeepStar.

The eight (8) major technological areas covered in Phase IV include

Regulatory

Flow Assurance 3.85 MM

Subsea - controls / pipelines / hardware

Vessels / Mooring / Riser

Drilling & Completion

Project Administration

Reservoir Engineering

MetOcean

As the program has evolved, we have recognized that the development of sub sea equipment although

necessary, does not have the same show-stopping character as our inability to provide flow assurance

over a long offset distance. The importance of this area is evidenced by the fact that -3.85 MM, the

largest chunk of the DeepStar budget, is devoted to this area of research. About 40 work programs

have received funding approval from the senior advisors with an average value of $325,000.

REGULATORY COMMITTEE

The Regulatory committee's primary purpose is information exchange. This effort is one of the most

important ongoing activities carried out by DeepStar. This forum gives DeepStar participants arid

the MMS a chance to discuss issues related to new development concepts that are departures from

existing regulations. By holding discussions, we can better understand the issues that need to be

addressed to ensure that new concepts are safe and fit for purpose. In addition, to being a forum to

feed technical questions arising out of committee work, key Phase IV efforts include

Targeting continuing discussion between regulatory authorities (Coast Guard/MMS) to sort

out overlap of regulatory domain and point out where gaps still exist.

247
248

Continuing to work with MMS to capture data from worldwide usage of FPS & FPSO's

database and help the MMS become comfortable with use of FPSO's in GUM.

Providing a forum for open industry discussion on these issues: for example the April 1997

forum jointly hosted by the MMS and DeepStar

FLOW ASSURANCE COMMITTEE

Goal: to gather the most extensive industry FA data set, to allow validation and improvement of FA

predictive software packages, and to field qualify new FA monitoring, management and remediation

technologies.

DeepStar had planned to conduct a series of four or five field tests, designed (1) to retrieve solids

deposition and multiphase flow data, and (2) to field test new monitoring, management and remediation technologies.

FLOW ASSURANCE PROGRAM

The Flow Assurance Committee, working with its contractors, vendors and other Industry programs

matured new hydrate and paraffin management technology to the point of performing full-scale field

trials and demonstrations (the last step prior to commercial deployment). The primary Phase IV - 4,200 activities are focused on this field demonstration objective. Hydrate management trials are

planned for both a multiphase black oil and for a condensate system (in a mist annular flow regime).

Wax deposition trials are in a single-phase black oil system.

These trials and demonstrations were originally planned for existing producing fields. Unfortunately,

suitable fields could not be found, either within Texaco or the DeepStar Participants, so the decision

was made to demonstrate the technologies in a full-scale simulator. DeepStar partnered with the

Department of Energy's Rocky Mountain Oilfield Test Center (in Casper, WY) to cost-share

construction of this test facility. Construction of the facility was begun on a fast-track program in

August 1998, but was halted in November 1998 when the actual facility costs exceeded budgeted

funds. A recovery program is being developed to resume construction early summer 1999.

The core of the Phase IV Flow Assurance program was a series of field tests. The objective of the

program was to retrieve sufficient multiphase flow and solids deposition data, to validate and

improve current FA predictive tools. In addition, available management and remediation

technologies were to be field qualified.

When the facility is finally constructed, instrumentation will be a key aspect of theprogram. We will

utilize both novel and established instrumentation systems, including fiber optics and solids

deposition monitors. As noted previously, the extensive and unique data recorded from thisprogram

will be used to validate and improve current FA predictive software.

We plan to field qualify available management and remediation technologies. These will include the

latest chemical developments for wax and hydrate inhibition, and possibly other novel approaches.
249

We will field qualify optimum depressurizing techniques for hydrate re-mediation and test the

suitability aggressive and multi-diameter pigs.

KEY FOCUS AREAS OF THE SUBSEA COMMITTEE

The stretch goal of the subsea committee is to provide subsea tieback technology in water depths to

10,000 ft.

In addition to chemical and mechanical strategies investigated by the Flow Assurance Committee,

we plan to field qualify an electrically heated pipe system. If this system proves to be a practical

solution, it would be able to keep the pipeline out of wax and hydrate formation conditions, and may

also be an excellent remediation tool. This final section of the program will be conducted under the

guidance of our subsea committee.

Other Areas to be studied include

testing subsea manifold large gate and ball valves for 10,000 ft. operation in higher pressure

ranges

DeepStar Pipeline Pigging Systems - haven't designed systems for wax removal on a

continuous basis

GOM Pipeline Repair Alliance

ELECTRIC IMPEDANCE PIPELINE HEATING

This appears to be the most viable commercial alternative to date. A voltage drop is applied directly

to a pipeline with an outer coating of insulation. This technology holds the promise of reaching

beyond 15 20 miles

VALVE CONCERNS

Problems with large bore high-pressure valves found on manifolds include

a long lead time

not off-the-shelf

reliability not fully established

PIPELINE REPAIR ALLIANCE

Recognizing that having equipment on hand for repair is unnecessarily expensive if each company

does so separately, a CTR was organized to explore the possibility of warehousing a communal

supply of emergency repair equipment.
250

VESSEL, MOORING, AND RISER COMMITTEE

The greatest effort has been focused on offshore testing of vertically loaded drag embedment anchors and components of a polyester mooring system.

TAUT LEG MOORING SYSTEM

As water depth increases, the spread ofa conventional mooring system could traverse several blocks. Taut leg systems, consisting of vertically loaded anchor systems, with flotation buoys could help reduce the areal extent and cost of a deep water mooring system. Further substitution of polyester instead of conventional chain and wire rope mooring could reduce system component costs as well as reduce deck loads.

Several DeepStar members were able to participate in the deployment of the system offshore. The basic system involved in deployment consisted of the polyester line on a spool, with a helper tug and the buoy, which tethers the system inside the A-frame, used for deploying the buoy.

POLYESTER MOORING SYSTEM TEST

The test seeks to

place steel taut leg mooring lines with lighter synthetic fibers

install system in 3,000 ft. water depth in Gulf of Mexico and gather data for two years

system instrumented to provide mooring line loads and buoy motions after 2 3 year deployment, polyester line will undergo wear and chemical degradation testing

This test should improve the acceptability of polyester mooring components with their potential cost savings. As the system was removed in November 1998, the post-test analysis which includes both destructive and non-destructive testing is underway.

Other Phase IV programs carried out by the Vessel, Mooring and Riser committee include

- Deepwater Mooring and Riser Analytic Capabilities Mooring and Risers Beyond 6,000 ft. Water Depth

Reliability Based Mooring Design Code

API RP 2FPX "Planning, Designing and Constructing Floating Production Systems"

DEEPSTAR DRILLING COMMITTEE

The number one GOM deepwater drilling issue has been management and control of shallow water flows (SWF). There are often large artesian aquifers within the firstfew thousand feet below the mud line over the target reservoirs. The geological mechanism, which deposited the target hydrocarbon reservoir, is often the same mechanism, which in recent geological times created these aquifers. Therefore, many of the GOM deepwater areas have this potential problem.
251

When well conductorj etting-in operations encounter these aquifers, excessive artesian water flows may wash away the soils surrounding the conductor resulting in well loss and formation of a large sea floor crater. Other times, the aquifer is deeper where it may cause problems during 20" conductor string cementing operations. These are Serious problems and DeepStar's drilling committee has worked extensively with the service industry in Phases hA and III to develop techniques and

products to manage these shallowwater flow problems. In Phase IV we have put continued effort

into engineering a test for driving conductor casing to a sufficient depth to obviate the need to set casing in the shallow water flow zone.

We are now wrapping up our effort to develop composite marine drilling riser with the National

Institute of Standards and Technology Program led by Northrup Grumman. The riser has been tested

at Vetco Gray in Houston. Some of the axial load cycles run to date include: 1) startup fixture test to 500 kips, 2) tension up through 1,500 kips design load, and 3) maximum tension of 1,850 kips. As testing has been successfully completed, the next step is to have an operator to agree to deploy this pup joint during drilling operations. Negotiations are underway. Separately, a second pup joint is being designed and tested to accommodate water depths to 10,000 ft

Other CTR's pursued by the drilling committee include

Bottom Driven Casing Test Installation Guidelines

Ultra-Deepwater Wellhead and Riser Standards

Well Control Software Refinements

Validation of SSSV Practices

Multi-Lateral Completion Reliability Forecasting

RESERVOIR ENGINEERING COMMITTEE

The entire production system is built to safely produce the reservoir. In the deepwater Gulf of Mexico, we are entering a new frontier with significantly different production characteristics from the experience of the Continental Shelf. The reservoir committee has studied available information

and identified many of the variables impacting production system design. These include high rate wells, one to four producing zones, and an estimated 50% of these reservoirs that will require water injection.

Further work planned for DeepStar Phase 4 will investigate water injection aspects and the effectiveness of multi-lateral and horizontal wells. These are all techniques to increase the production rates and the total reserves recovered from each welibore.

MET OCEAN COMMITTEE

This program is being conducted to make the first comprehensive measurements of current inflow into the Gulf of Mexico through the Yucatan Straight. This data gathering effort will be used to improve our Gulf of Mexico global current model with the ultimate goal of avoiding downtime during deepwater drilling operations. Field work will be done by a Mexican research institute
252

(CICESE). A budget of $850,000 has been awarded to Dynalysis of Princeton as the primary

contractor. We hope to kick off the deployment effort in April 1999.

CONCLUSION

Prototype testing now forms a greater part of the DeepStar program. This trend is foreseen to

continue as the Gulf of Mexico operators pick up the pace of deepwater development. For subsea

technology, flow assurance is our first concern and a major effort to develop a major test facility at

the DOE's RMOTC facility in Casper, Wyoming. Althoughwith DeepStar's breadth and emphasis

on technologies, the question the MMS needs to ask itself is "Why are we not actively participating

in DeepStar?"

Paul Hays received an erector set at age 6, and his dad suggested he could become an "engineer."

He received Ph.D. in theoretical and applied mechanics from the University of Illinois at Urbana,

Illinois in May 1980. After a brief stint in the aerospace industry, he joined the oil industry in 1981.

Early involvement with Deepwater focused on field development technology for 1,000 feet water

depth offshore Norway with initialtechnical focus on deep-water production and drilling technology.

He was involved with acquisition and development of technology to enable development with

floating production systems. Technology development efforts evolved to Gulf of Mexico (GOM)

focus with water depths to 2,200 feet.

In 1992, the DeepStar project began a program to develop technology to enable extended-reach

subsea tie-back field development in GOM water depths ranging between 3,000 - 6,000 feet. Dr.

Hays began work with DeepStar focusing on pipelines. As the program expanded in Phase II. He

took on greater responsibility for production risers. In Phase hA, Hays assumed additional

responsibility for drilling and completions commiftee, and he took over responsibility for leading

the overall DeepStar program at the kickoff of Phase Ill in February 1996. He proposed a $9 million

Phase IV program that has grown to approximately $13 million with the addition of four new

participants.
Long-Term Monitoring at the East Dr. Quenton R. Dokken, Co-Principal Investigator

and West Flower Garden Banks, Dr. Joim W. Tunnel!, Jr., Co-Principal Investigator 1996-1997 Center for Coastal Studies

Texas A&M University-Corpus Christi

Dr. Ian R. MacDonald, Co-Principal Investigator

Mr. Carl R. Beaver

Mr. Gregory S. Boland

Mr. Derek K. Hagman

Mr. Noe C. Barrera

Geochemical Environmental Research Group

Texas A&M University

The Interactions Between Neotropical

Bird Migrants and OCS Platforms

Stability and Change in Gulf of Mexico

Chemosynthetic Communities

(CHEMO II)

Shell Marine Habitat Program

Document Not Submitted

SESSION IE

STUDIES REPORTS AND RESEARCH INITIATIVES

Co-Chairs: Dr. Pasquale Roscigno and Ms. Debra Vigil

Date: December 9, 1998

Presentation Author/Affiliation

Dr. Robert W. Russell

Louisiana State University

Dr. Ian R. MacDonald

Program Manager

Geochemical and Environmental Research Group

Texas A&M University

Dr. Jerry Clark

National Fish and Wildlife Foundation

253
LONG-TERM MONITORING AT THE EAST AND WEST

FLOWER GARDEN BANKS, 1996-1 997

Dr. Quenton R. Dokken, Co-Principal Investigator

Dr. John W. Tunnel!, Jr., Co-Principal Investigator

Center for Coastal Studies

Texas A&M University-Corpus Christi

Dr. Ian R. MacDonald, Co-Principal Investigator

Mr. Carl R. Beaver

Mr. Gregory S. Boland

Mr. Derek K. Hagman

Mr. Noe C. Barrera

Geochemical Environmental Research Group

Texas A&M University

This report (Dokken et al. 1999) was produced by the Texas A&M University-Corpus Christi Center

for Coastal Studies and the Texas A&M University-College Station Geochemical and Environmental

Research Group through contract to the Minerals Management Service and the National Oceanic

Atmospheric Administration. This study represents an ongoing effort to understand the reef

dynamics of the Flower Garden Banks coral reefs, and to protect this unique and valuable natural

resource. Increased human activity (i.e. shipping, oil/gas exploration/production, recreational diving,

fishing) in the vicinity of the Flower Garden Banks National Marine Sanctuary, makes

research'monitoring efforts critical to preserving the long-term health and sustainability of the

Flower Gardens Banks ecosystem.

The Flower Garden Banks comprise a unique coral reef ecosystem located approximately 200-km

(110 nmi) southeast of Galveston, Texas, on the outer continental shelf of the northwestern Gulf of

Mexico. Designated as a National Marine Sanctuary in 1992, the Flower Garden Banks represents

the northernmost coral reef on the continental shelf of North America. The banks are topographic

highs of bedrock displaced upward by the intrusion of two salt diapirs. The bedrock is capped with

the calcium carbonate deposition of reef-building corals and calcareous algae. The living coral reef

is comprised of 20 species of corals, and supports 120 species of fishes and more than 250 species

of invertebrates.

This ecological monitoring effort is the continuation of monitoring efforts begun in 1989 and first

reported in 1992. Study purposes are:

to provide relevant and timely environmental data to those charged with developing policies

concerning oil and gas exploration and production in the vicinity of sensitive ecosystems,

to document long-term changes in reef-building coral and associated communities at the

Flower Garden Banks caused by either impacts of petroleum explorationand production or

other human impacts,

255
256

to document long-term natural variation in reef growth and associated communities on the

Flower Garden Banks and,

to stimulate ancillary research efforts and coordinate monitoring activities with agencies and

institutions conducting water quality assessments and other studies in the vicinity of the

Flower Gardens in order to better evaluate causes of environmental change.

Photographic techniques (i.e., random transects, encrusting growth, repetitive quadrats, and video

transects) were used to measure/assess the growth, diversity, percent cover, and incidence of

bleaching and disease of scleractinian bennatypic corals at the Flower Garden Banks. Accretionary

growth of corals was assessed using both direct measurement arid sclerochronology methodology.

Visual assessments of the population density of large-bodied fishes and sea urchins were made.

Long-term temperature and insolation (light attenuation) were measured on the reef. The water

column was sampled for contaminants using semi-permeable membrane devices (SPMD).

Additionally, surveys of sea urchin populations, micromolluscan fauna, and habitats were conducted

below the coral cap.

As in past studies, the Montastraea annularis complex (M annularis, M franki, M faveolata) was

the dominant coral, providing 29.2% and 28.3% cover on the East and West Bank, respectively.

Diploria strigosa was the second most common species of hermatypic coral with 13.1% and 10.0%

cover on the East and West Bank, respectively. Total percent coral cover did not vary significantly

between the East (54.4%) and West (49.8%) bank or between years. Analysis of species diversity

and evenness showed no significant difference among studies, banks, or 1996 -1997.

In 1997, 45% of East Bank colonies and 67% of the West Bank colonies of Montastraea cavernosa

showed substantial bleaching. Bleached colonies ofM annularis and Millepora alcicornis were also

observed in 1997. This was believed to be a response to unusual water temperature fluctuations in

1997. Water temperatures ranged from 20.1 to 30.1 °C at the East Bank and 20.2 to 30.0 °C at the

West Bank. Temperatures at the East Bank were lower than the seven year average for the period

from mid-April through mid-June 1977. Another apparent deviation from the seven year average

occurred from late July until mid-August 97 at the East Bank when daily temperatures were higher

than average. Daily water temperatures at the West Bank were higher than average from early March

thorough the first week of April and again from mid-June through early September 1997.

Mean accretionary growth at the East Bank was 5.7 nmilyear and 7.3 mm/year at the West Bank. The

encrusting growth rate was 3.7 and 4.0 rnmlyear at the East and West Bank, respectively. Average

net encrusting growth rates were 0.06 and 0.14 cm/year at the East and West Bank, respectively.

Coral disease was minimal, occurring in 0.006% of the 3,700 coral colonies examined. Dzploria

strigosa and Montastraea spp. were the most commonly afflicted corals. The overall loss of coral

cover due to disease was less than 0.03%.

Analysis of fish counts did not indicate any trends, but some significant differences did occur. Creole

fish (Paranthiasfurcfer) were significantly more abundant in 1996 than 1997. Compared to 1991,

density of all large bodied fish combined on the West Bank was significantly greater in 1996/1997,
257

as was the density of the creole fish and creole wrasse (Clepticusparrai). 1996/1997 density of the

queen parrotfish (Scarus vetula) was significantly greater on the East Bank than in 1991.

Water chemistry indicated the presence ofpolycyclic-aromatichydrocarbons (PAH) at the West (273 ng/l) and East Banks (290 ng/l) from February to September 1997. From September 1996 to

February 1997, 1,023 ng/l of PAH was recorded at the East Bank. The source of PAH was likely

natural hydrocarbon seepage, condensate oil seepage, or combusted ship fuels. The reader is

cautioned that: 1) the concentrations measured (ng/liter = parts per trillion) are infinitesimal, and 2)

the application of the semi-permeable membrane devices to record these contaminants was done

under less than ideal conditions. We advise against drawing conclusions from this information.

Further study is warranted.

Pesticides and PCBs were also recorded. The amount of 4,4-DDE (West Bank = 49.5 ng/l; East

Bank = 43.5 ng/1) and 4,4'-DDT (West Bank 23.6 ng/l; East Bank = 21.6 ug/l) were similar from

the two sites collected from February to September 1997. The 4,4-DDE (93.2 ng/l) and 4,4'-DDT

(39.4 ng/l) were almost twice as high September 1996 to February 1997. The concentration of DDT

relative to its derivative DDE suggests recently used DDT. The source and impact of these pesticides

is not known. As with the application of semi-permeable devices to record PAH data, further study

is warranted before drawing conclusions.

Other contaminants were detected, including:

chlordane and its metabolites

dieldrin

hexachlorobenzene and its metabolites

lindane

PCB congeners

Analysis of attenuation coefficients (k) indicate that the water column at the Flower Garden Banks

falls between the published values for the clearest coastal water (k=0. 15) and the clearest oceanic

waters (k=0.033). Analysis of trends in kvalues suggests that at least two attenuation regimes related

to plankton blooms that reduce water column transmissivity. It appeared that blooms were periodically flushed by the infiltration of oceanic water.

Surveys and habitat characterizations of deep (30 to 50 m) reef zones further substantiate the

biogenic zonation correlated to depths previously described. More investigation is required to

describe the interactive dynamics of the coral cap with the deeper adjacent habitats.

Transect surveys of sea urchins, a primary herbivore, were conducted at each bank during both

sampling periods. Based on the data, it was concluded that the sea urchin population continues to

be depressed, and that it did not vary significantly between sampling years or banks. During the 1996

transect surveys one sea urchin was counted, and during the 1997 survey, three urchins were counted.
258

Micromolluscs from sand samples are currently being identified and counted. To date, 114 species

representing 50 families have been identified, increasing by one-third the previously known

invertebrate fauna of these reefs.

CONCLUSIONS

The dominant corals of the Flower Garden coral reef ecosystem continue to grow at rates consistent with past measurements.

The incidence of coral diseases is minimal and inconsequential at this time.

The corals responded to elevated temperatures by exhibiting mild bleaching in 1997.

Fish numbers showed limited variation, but no trends were apparent.

Polycyclic-aromatic hydrocarbons and pesticides were present in the water column, but at

minute levels (i.e. parts per trillion). Impact is not known.

The sea urchin population continues to be depressed.

The molluscan fauna has only been partially described in past studies, and it is likely that

more intensive sampling of other groups of organisms would substantially increase the

recorded biodiversity at the Flower Garden Banks.

The strength of the monitoring strategy as has been applied since 1989 is that is provides a

long-term database of repeatablemeasures of growth and condition of the scleractinian corals

forming the habitats of the Flower Garden coral reefs.

The weakness of the monitoring strategy as has been applied since 1989 is that it does not

adequately assess the interactive dynamics of the Flower Garden coral reef ecosystem to

describe the ecosystem dynamics. More measures need to be taken assess cause and effect

relationships.

RECOMMENDATIONS

Eliminate growth spikes as a method for measuring accretionary growth. Use

sclerochronology measurements to measure accretionary growth exclusively.

Continue and expand water chemistry analysis using SPMD technology. Record data no less

than quarterly.

Expand water chemistry analysis to include nutrients (nitrogen and phosphorous) on a

schedule no less than quarterly.

The protocol and technology applied to the measurement of light characteristics should be

enhanced to allow diurnal collections, particularly during the late summer months before and

after the annual spawning event.

Use random photographic transects outside the boundaries of the lOOm2 study sites to test

the representativeness of the designated study sites.

Continue analysis of sea urchin population densities on a quarterly basis.

Add qualitative and quantitative analysis of macroalgae.

Add fish census (stationary visual and!or roving diver census) to suite ofmeasurements.

Add seasonal photographic transects to assess temporal occurrences, such as disease and

bleaching.
259

Continue and expand monitoring and studies of the biogenic zones below the coral cap.

Trophic structure analysis should be undertaken to describe biological energy linkages

between the biogenic zones.

Measure seasonal and annual current patterns around and above the Flower Garden Banks.

Develop and apply dynamic ecosystem models to research and management decision making

REFERENCES

Dokken, Q.R., I. R. MacDonald, J.W. Tunnell, Jr., C. R. Beaver, G. S. Boland, and D. K. Hagman.

1999. Long-term monitoring at the East and West Flower Garden Banks, 1996-1997. OCS Study

MMS 99-0005, U.S. Department of the Interior, Minerals Mgmt. Service, Gulf of Mexico OCS

Region, New Orleans, LA. 101 pp.

THE INTERACTIONS BETWEEN NEOTROPICAL

BIRD MIGRANTS AND OCS PLATFORMS

Dr. Robert W. Russell

Louisiana State University

Each spring, approximately a billion Iandbirds migrate northward across the Gulf of Mexico, en

route to breeding habitats from their wintering quarters in the tropics. Following a short breeding

season in the north, most of these birds return southward across the Gulf, their numbers then

augmented by offspring produced over the summer From the standpoint of sheer numbers, these

annual trans-Gulf migrations constitute one of the great wildlife events of the world. Nevertheless,

basic aspects of the migrations remain poorly understood; indeed, until the 1950s, some scientists

treated the very idea that birds routinely and ThintentionallylT migrate across the Gulf with skepticism.

Radar studies have indicated that the flight pathway of the majority of trans-Gulfmigrants in spring

is directed toward the coasts of east Texas and Louisianaand thus over Gulf waters in which are

located the majority of OCS platforms. Indeed, the 4000 platforms located on the continental shelf

of the northern Gulf of Mexico make up the largest artificial island system in the world. One of the

most important components of birds' migration strategies is their use of local habitats for resting and

refueling while en route. In light of the absence of natural islands or other terrestrial habitats during

crossings of the Gulf of Mexico, it seems inevitable that the installation of 4,000 artificial islands

in the northern Gulf must affect migrants in some fashion. Indeed, it may not be too fanciful to

speculate that this recent availability of potential offshore stopover sites might even be affecting the

evolution of bird migration strategies. However, to date, no systematic studies have examined the

interaction between platforms and migrating birds.

To fill this informational void, an MMS-sponsored study of migrant-platform interactions began in

spring 1998. The study is being carried out by personnel based at the LSU Museum of Natural
260

Science, and funded by MMS through a cooperative agreement with the LSU Coastal Marine

Institute. Five major petroleum companies (Mobil, Exxon, BP, Phillips, and Texaco) are making

platforms available to the study and are providing in-kind support. The goal of this research is to

answer questions such as the following:

How many individual migrating birds, and of which species, use platforms? How and when

do they use platforms? How are the numbers of migrants using platforms related to migration

traffic aloft?

What proportion of migrating birds that stop on platforms depart successfully versus die

there? Why do some birds die?

What is the relationship between weather and trans-Gulf migration? In particular, how do

local and synoptic conditions jointly determine the use of and survival on platforms by

migrants?

To answer these questions, a team of five expert observers has been deployed to OCS platforms off

the Louisiana coast during spring (15 March-15 May 1998) and fall (15 August-31 October 1998).

Field methods are simple but powerful. The basic protocol consists of a time-designated census

conducted by an observer while walking around the platform on a prescribed route, designed to

provide a synoptic and comprehensive assessment of platform use by migrants. The platform census

is repeated identically seven times throughout the day from pre-dawn to post-sunset, allowing us to

determine when birds arrive and when they leave. When we detect a bird, we identify it to species

and when possible age and sex; we record its location on the platform; we assess its likely body

condition on a four-point scale based on behavioral cues such as alertness, vigor, and apparent

thermal stress; and we note whether it is looking for food and whether or not it finds any.

The platform censuses are intended to provide information on platform use by migrants. Because not

all incoming migrants land on platforms, it is important to obtain independent information on

incoming migration traffic. Thus, in addition to the platform censuses, we conduct several surveys

from a fixed point of the airspace over and around the platform. When we detect a bird in flight, we

record its flight altitude, whether or not it approaches the platform, and its vanishing bearing (the

direction toward which it departs). Throughout the day and between the other censuses, we conduct

routine searches for dead birds. Any carcasses that are discovered are salvaged, labeled, frozen, and

transported to the Museum for necropsy.

An important adjunct to the fieldwork on the platforms is the remote observation of migration over

the Gulf using land-based radars. The National Weather Service recently completed the installation

of a national network of modern Doppler radars, which replaced technology dating from the 195 Os.

The new radars (called NEXRAD) can ideally provide both large-scale distributional information

as well as quantitative measures of the local abundance of bird migrants in the airspace. Currently

there are 10 NEXRAD radars in operation at sites around the Gulf Coast, providing an observational

network stretching from Brownsville to Key West.

Based on our first two field seasons, our preliminary conclusion is that the aggregate impact of

platforms on migrating birds is neutral to moderately positive. In both spring and fall, platforms are
261

exploited by large numbers of migrants for resting and refueling opportunities. During the spring,

most of the mortality we observed was not caused by the platforms either directly or indirectly, and

we documented unambiguous benefits to migrants in the form of successfulfeeding on the abundant insects that are transported offshore by wind. Many migrants that otherwise would likely have

perished in the Gulf during severe spring weather were observed to take refuge on platforms, survive

the severe weather, and then continue their migrations.

The situation is more complicated in the fall because the costs and benefits of platforms accrue

differentially to different classes of migrants. Fortrue trans-Gulf migrants, a minor adverse impact

was evident in the form of small levels of mortality resulting from collisions with platforms, particularly during tropical storms. In addition to the true trans-Gulf migrants, we were surprised to discover an abundance of species that are shorter-distance migrants and do not winter to the south

of the U.S. A variety of evidence indicates that these migrants "overshot" the coastline during the previous night's migration and inadvertently ended up over the Gulf. These birds reorient to the north at first light, and while attempting to make it back to shore, they often stop on platforms and

feed heavily on the abundant moths that also ended up offshore inadvertently. Thus, for the

"overshoot" migrants, which are ill equipped to deal with the rigors of overwater migration,

platforms provide "steppingstones" back to the coast and probably enable many individualsto return

to land successfully.

Although OCS platforms may be beneficial to some migrants, their most important impact may prove to be their tremendous value as research platforms for learning more about the ecology of

trans-Gulf migration. Our understanding of trans-Gulfmigration has already taken a quantum leap

forward, but the first year of fieldwork has also raised a number of important questions. For example,

the portion of the northern Gulf Coast on which migrants make landfall changes dramatically from

day to day, often reflecting patterns of upper-level winds. This variation raises the question of whether different species use different trans-Gulf flight routes or whether migrants of all species opportunistically use whichever flight route is most efficient given current wind conditions. Another

surprising discovery was the observation of large numbers of radar targets of unknown identity over

the western part of the Gulf. Because of the relatively limited geographical configuration of our

current platform layout, we are seeking to expandto ten platforms to provide a more comprehensive

circum-Gulf perspective. If successful, this expansion of the platform network will allow us to

"ground-truth" the radar observations across the northern Gulf and examine the possible existence

and consequences of specie s-specific migration corridors.
262

STABILITY AND CHANGE IN GULF OF MEXICO CHEMOSYNTHETIC

COMMUNITIES (CHEMO II)

Dr. Ian R. MacDonald

Program Manager

Geochemical and Environmental Research Group

Texas A&M University

INTRODUCTION

On the northern continental slope of the Gulf of Mexico, chemosynthetic communities are known

to occur between longitudes 94° W and 88° W, at depthsbetween the 400 and 2,200 m (MacDonald

et al. 1996). These communities comprise dense and productive aggregations of benthic organisms

that are dominated by chemosynthetic tube worms and mussels, but also include many benthic

invertebrates and fish that are common throughout the Gulf slope (MacDonald ci' al. 1989). The

chemosynthetic fauna is dependent upon methane and hydrogen sulfide dissolved in pore-fluid and

very-near-bottom sea water. Methane supports mussels and hydrogen sulfide supports tube worms

(Fisher 1990). The presence of these gases in the Gulf slope sediments is directly linked to migration

of hydrocarbons from deep sub-surface reservoirsto the seafloor and the water column (Kennicutt et al. 1988). The greatest management concern is directed at communities with aggregations that

extend over a large area and where the local high productivity supports a diverse assemblage of heterotrophic fauna.

Considerable progress was made in the understanding of chemosynthetic communities in the Gulf of Mexico during the early 1 990s, particularly as a result of the MMS Program entitled "The

Chemosynthetic Ecosystem Study" (CHEMO I). However, there remained many unanswered

questions and many areas where qualified scientists and managers disagreed. The continuation of CHEMO was a new, 42-month program entitled "Stability and Change in Gulf of Mexico

Chemosynthetjc Communities" (CHEMO II). It was inaugurated at the beginning of the 1997 fiscal

year and was designed to aid MMS in the scientifically sound management of seep communities. CHEMO II has now completed all of the scheduled field collections. The program principal

investigators are close to completion of sample analysis and are preparing for a yearlong effort that will produce the program's final report.

This summary gives a brief overview of the CHEMO II program goals, study design, and

participants. It describes progress during the past year, and it highlights the accomplishments of each program element.

PROGRAM OVERVIEW

The CHEMO II program includes community ecological, regional geological, microbial, and sitespecific chemical and oceanographic studies. At the regional level, the program has been concerned with developing reliable methods for remote detection of significant chemosynthetic communities.
263

During the 1997 field season, side-scan sonar surveys of suspected chemo synthetic communities

were carried out in two regional mega-sites (Figure 1E.1). During FY 1998, US Navy Submarine

NR-1 was fitted with a laser line scan system and an X-Star Subbottom Profiler and was used to

survey known and suspected communities to confirm interpretation of the sonar data.

The size and location of mega-sites were designed to optimize survey operations and provide

significant regional coverage. Both areas encompass several types of geological formations. Both

contain more than ten perennial sea surface slicks detected by remote sensing techniques. Additional

survey data were collected at the Garden Banks (GB) 425 sampling site in support of the communitylevel studies. Characteristic of the mega-sites are summarized below:

1) Megasite 1 ("Shallow") - area 1214 km2

Boundaries - 91°35'W-91°10'W; 27°36TN-27050'N

Contains Green Canyon (GC) blocks 185, 233, and 234 sampling sites.

d) Water depths range from 400-900 m

2) Megasite 2 ("Deep") - area 1214 km2

Figure 1 E. 1 Northern Gulf of Mexico showing study site locations for submersible operations

(triangles) and mega-site areas for geophysical survey (shaded rectangles). Depth

contours are in meters.

94W 93GW 92GW 91 W 90'W 89W

A -

3ON

4 1

28N

27N

pGBO

,Gc185Gc234

..,;

Q1k1 ,
264

Boundaries - 9103 5'W-9 1°l OW; 2701 O'N-27°26'N

Contains northern Pygmy Basin; eastern Longhorn Basin; and most of Tiger Basin

(intrasalt basins)

d) Water depths range from 950 to 1250 m

At the community level, efforts focus on the abiotic factors that control the distribution, abundance,

and health of the major chemosynthetic and associated fauna. Investigations of the life history of

these organisms are also included. Field work during 1998 has required the use of the manned

submersible Johnson Sea-Link I. These submersibles wereused to collect samples from a series of

stations within each of four detailed study sites (Figure 1E.1). Characteristics of the sampling sites

are summarized in Table 1E. 1

Table 1 E. 1. Summary of principal conmnmity-level sampling sites and pertinent characteristics.

(For locations, see Figure 1E.1.)

Sampling Site

abbreviation

Latitude,

Lon itude

GB425 27033.2T N

[Garden Banks (GB)] 92°32.4' W

600 mussels brine

heterotrophs (?) free and dissolved methane gas

tube worms high molecular weight hydrocarbons

PROGRAM TEAM

Program objectives are being carried out by a multidisciplinary team of investigators. The principal

investigators, their area of expertise, and the members of the Scientific Review Board are listed in

Table 1E.2.

PROGRAM MILESTONES ACCOMPLISHED DURING FY 1998

The CHEMO II program moves into its third year, having successfully completed all of the

scheduled fieldwork. Milestone accomplished during this period were as follows:

The Interim Report has been accepted by the government and submitted in final form.

tube worms high molecular weight hydrocarbons

heterotrophs free methane to pentane gases

mussels

tube worms high molecular weight hydrocarbons

heterotrophs free methane to pentane gases

mussels

mussels brine

heterotrophs free and dissolved methane gas

tube worms

Fauna present

Death m b dominance See a a e ro a erties

GC185 27°46.9' N 550-580

[Bush Hill (BH)] 91°30.4' W

GC234 27°44.ltN 525-560

[Green Canyon (GC)] 91015.3 W

GC23 3 27°43.4' N 640

[Brine Pool (BP)} 91°l6.8 W
Table 1E.2. Program team and roles.

Dr. Norman L. Guinasso, Jr.

Physical Oceanography

Dr. Mahiori C. Kennicutt II

Deputy Program Manager

Environmental Chemistry

Dr. Samantha Joye

University of Georgia

Electrochemistry

Dr. Robert Carney

Louisiana State University

Trophic Relationships

Dr. Charles F. Fisher

Pennsylvania State University

Physiological Ecology

Dr. James Barry

Monterey Bay Aquarium

Research Institute

Texas A&M University Investigators

Geochemical and Environmental Research Group

Dr. Ian MacDonald

Program Manager

imaging & GIS

Dr. Roger Sassen

Hydrocarbon Chemistry

Department of Oceanography

Dr. John W. Morse Dr. William Sager

Inorganic Chemistry Geophysics

Principal Investigators Not at Texas A&M University

Dr. Gary A. Wolff

Data Management

Dr. Steven Macko

University of Virginia

Trophic Relationships

Dr. Paul Montagna

The University of Texas at Austin

Statistical Design

Dr. Kimberlyn Nelson

Pennsylvania State University

Molecular Ecology and Genetics

Scientific Review Board

Dr. Cindy Lee Van Dover

Dr. Douglas C. Nelson

University of California, Davis

Microbial Ecology

Dr. Eric Powell

Rutgers University

Histopathology and Community

Health

Dr. Steve Schaeffer

Pennsylvania State University

Molecular Ecology and

Genetics

Dr. William W. Schroeder

University of Alaska The University of Alabama

265

The Annual Program Review arid Cruise Planning Meeting was held in College Station

during 13-15 March 1998.

Submarine survey cruise 18-22 May 1998 (NR1 -98). This opportunistic cruise aboard Navy

Submarine NR1 deployed laser line-scan and high-resolution subbottom instruments for

survey of the primary sites and suspected chemosynthetie communities identified during
266

TAMU2-97 cruise. Mechanical failure by the NR1 curtailed the cruise after five days of

operation, but much valuable data was collected during this time.

Submersible sampling cruise 1-15 July 1998 (JSL-98). This cruise aboard RJV EDWIN

LINK utilized the submersible Johnson Sea-Link Ito collect samples from the four primary

study sites. Sampling activities for the program expanded due to cooperative funding from

the Naval Research Laboratory.

Progress descriptions by individual investigators detailed in the oral presentation indicate timely

completion of contract obligations with few shortfalls and no problems wbichjeopardize the overall

objectives of the program. If progress continues at the present rate, analysis of samples will be

largely completed by the end of the first quarter of 1999.

REFERENCES

Fisher, C.R. 1990. Chemoautotrophic and methanotrophic symbioses in marine invertebrates.

Reviews in Aquatic Sciences. 2 (3/4). 399-436.

Kennicutt, M.C., J.M. Brooks, and G.J. Denoux. 1988. Leakage of deep, reservoired petroleum to

the near surface on the Gulf of Mexico continental slope. Marine Chemistry. 24. 3 9-59.

MacDonald, I.R., G.S. Boland, J.S. Baker, J.M. Brooks, M.C. Kennicuttil, andR.R. Bidigare. 1989.

Gulf of Mexico chemosynthetic communities II: spatial distribution of seep organisms and

hydrocarbons at Bush Hill. Marine Biology. 101. 235-247.

MacDonald, I.R., J.F. Reilly Jr., S.E. Best, R. Venkataramaiah, R. Sassen, J. Amos, and N.L.

Guinasso Jr. 1996. A remote-sensing inventory of active oil seeps and chemosynthetic

communities in the northern Gulf of Mexico in Hydrocarbon migration and its near-surface

expression, ed. D. Schumacher, and M.A. Abrams. pp. 27-37. Amer. Assoc. Petrol. Geol.

Ian R. MacDonald is an Associate Research Scientist at the Geochemical and Environmental

Research Group of Texas A&M University. His primary research interest is the application of

imaging and GIS techniques for marine ecology. He is the program manager for the Stability and

Change in Gulf of Mexico Chemosynthetic Communities Program. MacDonald received a Ph.D. in

oceanography in 1990 from Texas A&M University.
Northeastern Gulf of Mexico Coastal and

Marine Ecosystem Program: Coastal

Characterization: An Overview and Update

Evaluation of Mitigation Activities Related

to OCS Pipelines, Pipeline Canals, and

Navigation Channels

OCS Pipeline and Navigation Canal Habitat

Change StudyLouisiana

Document Not Submitted

Northeastern Gulf of Mexico Wetland and

Seagrass Study Summary

Document Not Submitted

Northeast Gulf of Mexico Habitat Mapping

Development and Jrnplementation of the

Northeastern Gulf of Mexico Coastal

Characterization and Data Information

Management System and Data Transfer

Computer Demonstration

SESSION IF

COASTAL STUDIES AND CHARACTERIZATION

Co-Chairs: Dr. Robert Rogers and Mr. Sam Holder

Date: December 9, 1998

Presentation Author/Affiliation

267

Dr. James B. Johnston

Mr. Lawrence R. Handley

Mr. William R. Jones

Mr. Steve Robb

USGS, National Wetlands Research Center

Dr. Donald R. Cahoon

USGS, National Wetlands Research Center

Mr. John A. Bourgeois

JCWS, National Wetlands Research Center

Dr. James Johnston

USGS, National Wetlands Research Center

Dr. James Johnston

USGS, National Wetlands Research Center

Mr. Lawrence R. Handley

USGS, National Wetlands Research Center

Mr. William R. Jones

Ms. Helena Schaefer

USGS, National Wetlands Research Center
NORTHEASTERN GULF OF MEXICO COASTAL AND MARINE ECOSYSTEM

PROGRAM: COASTAL CHARACTERIZATION: AN OVERVIEW AND UPDATE

Dr. James B. Johnston

Mr. Lawrence R. Handley

Mr. William R. Jones

Mr. Steve Robb

USGS, National Wetlands Research Center

tNTRODUCTION

The U.S. Geological Surveys Biological Resources Division (BRD) mission is to provide leadership

in gathering, analyzing, and disseminating biological information as support for sound management

of the Nation's natural resources. Since becoming operational in October of 1996 through the

transfer of programs from various bureaus within the Department of the Interior, the BRD, in

cooperation with other Federal, State, and local partners, has begun research, inventory and

monitoring, information sharing, and technology transfer. Through these activities, the BRD is

fostering an understanding of biological systems and their benefits to society, and providing the

essential scientific support and technical assistance required for management and policy decisions.

The role of BRD' s National Wetlands Research Center (NWRC) in Lafayette, Louisiana, with

project offices in Baton Rouge, LA and Gulf Breeze, FL, is to provide leadership in research and

development related to the Nation's natural resources for the Southeast. The research focuses on

wetlands ecology, animal ecology, and the development and application of spatial analysis

techniques for natural resource related studies.

Current geographic information system (GIS) technologies in use at NWRC are designed to provide

natural resource managers with the on-line data and computerized techniques necessary to make

informed decisions. Major GIS activities at NWRC include: compilation and analysis of digital

databases for monitoring of natural resources; integration and transfer of databases with existing

digital databases from various sources into a comprehensive GIS; and development of

multifunctional decision support systems for natural resource managers using these data. NWRC is

also an active participant in the National Information Infrastructure (NIT), in particular the National

Spatial Data Infrastructure (NSDI) and the National Biological Information Infrastructure (NBTI),

which will facilitate the dissemination of research results and other knowledge and information

gained from these efforts. This summary and the three summaries that follow provides an overview

and update of a four year study entitled, Northeastern Gulf of Mexico Coastal and Marine Ecosystem

Program: Coastal Characterization.

OVERVIEW

The offshore oil and gas industry is developing oil and gas resources in the eastern Gulf of Mexico,

a frontier area. The coastal area adjacent to the proposed development contains natural resources and

socioeconomic infrastructures that may be affected by the proposed activities. During the mid 1 970s

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to 1 980s, available environmental and socioeconomic information pertaining to the Gulf of Mexico

coastal habitats was synthesized for the Minerals Management Service in a series of Coastal

Ecosystem Characterizations. The data bases for these characterizations are now 10 to 20 years old

and are in need of being updated. For the proposed offshore oil and gas development to proceed in

a timely manner, Federal, State, and local agency and private decision-makers need current

information on coastal natural resource and processes and socioeconomic infrastructure upon which

to base their decisions.

The Minerals Management Service (MMS), in response to the need for an integrated overview of

coastal ecosystems, entered into a cooperative agreement with the, U.S. Geological Surveys National

Wetlands Research Center (formally apart of the U.S. Fish and Wildlife Service) to prepare a series

of Coastal Ecosystem Characterizations in areas of the Gulf of Mexico that might be effected by

offshore oil and gas development. These characterizations compiled existing information and data

by utilizing a holistic approach to identify functional relationships among natural processes and

components of coastal ecosystems. The characterization approach is designed primarily to integrate

environmental and socioeconomic data in a form useful for planning, impact assessment, and

analysis, and to identify research needs. It is a tool that enables decision-makers to address problems

including planning for urban and industrial developments, determining corridors for pipelines, siting

of onshore and offshore facilities for OCS oil and gas activities and determining priorities for future

research.

This Northeastern Gulf of Mexico (study) Coastal Characterization update includes the coastal areas

of southeast Louisiana, Mississippi, Alabama, and the Florida panhandle and focuses on updating

the data related to the previous characterizations of area. The existing characterizations (2), the

Mississippi Delta Plain Region (southeastern Louisiana and Mississippi) and the Northeastern Gulf

of Mexico Coast (Alabama and the Florida panhandle) are based on data that is now over 15 years

old.

UPDATE

This update centers on the status of data collected for biological resources, socioeconomic features,

and the data management aspects of efforts. Other papers in this session address wetlands,

seagrasses, and live bottoms. Data searches in Mississippi, Alabama, and Florida are completed. The

greatest number of datasets were in Florida. Over fifty were identified that have applicability to the

Outer Continental Shelf oil and gas program. The Florida Game and Fresh Water Fish Commission

and Florida Department of Environmental Protection were the leading contributors of data. For

Mississippi, the Mississippi Automated Resource Information Service and Mississippi Department

of Marine Resources supplied majority of data sets (20) with South Alabama Regional Planning

Commission and the U.S. Fish and Wildlife Service for Alabama (12 datasets). NWRC is also

completing Thematic Mapper (TM) satellite image backdrop for study area. For coastal erosion rates,

there were no digital data so the updated (1989-1995) wetland maps and the 1979 and 1956 maps

will be used to produce shoreline erosion data. Shellfish data was supplied by the National Oceanic

and Atmospheric Administration Shellfish Program. By mid-1998, data set will be in a data

dictionary housed on NWRCs Spatial Data and Metadata Server (http://www.nwrc.gov/sdms). The
Dr. James B. Johnston serves as the Chief of Spatial (Habitat) Analysis at NWRC in Lafayette,

Louisiana. Larry 1-landley serves as a Supervisory Geographer at NWRC. William Jones and Steve

Robb are GIS Project Leaders at NWRCs Lafayette, Louisiana, and Gulf Breeze, Florida offices,

respectively.

EVALUATION OF MITIGATION ACTIVITIES RELATED TO OCS PIPELINES,

PIPELINE CANALS, AND NAVIGATION CHANNELS

Dr. Donald R. Cahoon

USGS, National Wetlands Research Center

Mr. John A. Bourgeois

JCWS, National Wetlands Research Center

The Minerals Management Service funded project Coastal Wetland Impacts - OCS Canal Widening

Rates and Effectiveness ofOCS Pipeline Canal Mitigation" is entering its second year. This project's

goal is to provide insights into improving the effectiveness of workable mitigation techniques and developing new mitigation techniques that can be used in regions where existing mitigation

tecimiques have not been successful. This goal will be achieved from an assessment of(1) the types

and severity of adverse impacts caused by OCS-related pipeline and canal projects and (2) the

effectiveness of mitigation efforts to minimize or restore adverse impacts. Separate assessments will

be conducted for the Western and Central Planning Areas ofthe Gulf of Mexico and for coastal

barrier/beach dune and wetland habitats within each planning area, in order to compare habitat

impacts/mitigation effectiveness in the different geomorphic settings typical of the northern Gulf of Mexico.

The primary tool for assessing impacts/mitigation effectiveness will be GIS analysis of historical

aerial photography of select pipelines and navigation channels coupled with a literature review,

interviews with agency and industry personnel, and ground-truthing. The project is coordinated

through the Spatial Analysis and Wetlands Ecology Branches of the National Wetlands Research

Center. The Gulf of Mexico study area has been divided into five (5) sampling subareas:

A. Western Planning Area Sampling Subareas

Texas Barrier Islands

Texas Chenier Plain

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data will either be on the server or hot linked to agency who has data. Lastly, the wetlands and

seagrass data will also be on server, as well as, live bottom report. Project is scheduled for

completion in December 1998.
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B. Central Planning Area Sampling Subareas

Louisiana Chenier Plain

Louisiana Deltaic Plain

Mississippi/Alabama Coastal Plain

From each of these subareas, five (5) OCS pipelines and two (2) OCS navigation channels will be

identified for detailed GIS analysis. For the selection of thesepipelines and channels, several criteria

must be taken into account. The first priority in the selection process is that the pipelines and

navigation channels must be OCS related. Secondly, we are looking for pipelines that represent a

variety of mitigation types and/or construction methods and that cross a variety of habitat types.

Given this criteria, we can evaluate the effectiveness of the different mitigation types in relation to

the typical geomorphic settings in the Gulf of Mexico.

METHODS AD RESULTS

Analysis of the typical rates of secondary impacts as well as the effectiveness of mitigation along

OCS pipelines and navigation channels has occurred primarily through literature review, interviews,

and permit acquisition. The information gathered to date has been in an attempt to make the best

decision possible with regards to final selection of pipelines for GIS analysis. Impacts associated

with OCS pipelines have come from review of literature and through interviews with agency

personnel, private land owners and members of industry. The impacts of primary concern are the

following:

Direct Impacts

conversion of wetland habitat to open water and upland

Indirect Impacts

* changes in surface hydrology

changes in groundwater hydrology

changes in sedimentation patterns

compacted marsh surface/flank subsidence

erosion

* poor revegetation

soil oxidation

habitat degradation (esp. fisheries)

acute disturbances during construction

We have acquired over 160 permits (section 10, section 404, CUP, ROW) representing over 75

pipelines in Louisiana alone. These permits provide most of the information on construction method

as well as on the type of mitigation performed. The mitigation types most commonly found

throughout the Gulf of Mexico are the following:
backfihling

bulkheads/plugs/etc.

push-pull method

directional drilling

revegetation

imported material

double-ditching

water control structures/marsh management

The analysis of the Mississippi/Alabama Coastal Plain will be completed easily, as these states have

managed to avoid the majority of adverse impacts by consolidating pipeline landfalls into a very few

corridors and by directionally drilling under the coastal wetlands. We have recently made the

appropriate contacts with state officials in Texas and have initiated permit searches for that state. The

majority of our effort has been spent in Louisiana, where we are ready to make final selection of

pipelines pending some preliminary information from Texas so that we can be sure our analysis is

representative of the habitats and mitigation types occi.n-ring throughout all subareas.

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Dr. Donald R. Cahoon has worked for the past seven years as a Senior Research Ecologist at the U.S.

Geological Survey, National Wetlands Research Center, in Lafayette, Louisiana. Over the past 16

years, he has worked in the wetland regulatory field and conducted research on wetland mitigation

and restoration, and wetland sedimentation processes in coastal Louisiana as an employee of the

Louisiana Department of Natural Resources, Louisiana State University, and USGS. Dr. Cahoon

received his B. A. in botany from Drew University and his M.S. and Ph.D. in wetland plant ecology

from the University of Maryland.

Mr. John A. Bourgeois has worked at the National Wetlands Research Center since September 1997

as a General Biologist II for Johnson Controls World Services. Prior to this, Mr. Bourgeois worked

for the Louisiana Department of Natural Resources and the U.S. Forest Service. His primary interest

lies in wetland restoration. He received a B.S. in biology from Tulane University and an M.S. in

biology from the University of Southwestern Louisiana.
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Mississippi

Louisiana

NORTHEAST GULF OF MEXICO HABITAT MAPPING

Mr. Larry Handley

USGS, National Wetlands Research Center

As part of the Northeast Gulf of Mexico Ecological Characterization Update, the National Wetlands

Research Center (NWRC) was tasked with providing updated wetland and upland habitat maps at

1:24,000 scale for northeastern Gulf of Mexico to aid in the assessment of environmental impacts

ofpennitting, construction ofprojects, and potential oil spills (Figure 1 F. 1). The National Wetlands

Research Center and the National Wetlands Inventory had previously mapped coastal Mississippi

for 1956 and 1978, coastal Alabama for 1956, 1978, and coastal Florida for 1956 and 1978 as parts

of three ecological characterization projects of the early 1980's funded by the Minerals Management

Service's forerunner, the Bureau of Land Management's Offshore Division. Coastal Alabama was

mapped again using 1988 aerial photography as part of a project funded by the U.S. Fish and

Wildlife Service, the Alabama Department of Economic and Community Affairs, and the EPA's

Gulf of Mexico Program.

The Ecological Characterization Update targeted coastal areas along the northern Gulf of Mexico

from the Chandeleur Islands of Louisiana to Cape San Blas, Florida. Color infrared aerial photography was acquired by NASA Ames Research Center at a scale of 1:65,000 for the area in February

1996. The NWRC has duplicated over 1,400 copies of these frames of photography, and, working

with the University of Southwestern Louisiana' NASA Regional Application Center, has scanned

the 189 frames of aerial photography for coastal Mississippi, 100 frames of the photography for

Chandeleur Islands

Alabama

Figure 1 F. 1. Areas of 1996 Wetland Habitat Mapping Update.

Mobile

Cape San Bias

Georgia

Pensacola Florida
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coastal Alabama, and 160 frames for the Panhandle of Florida at 300 dots per inch and produced CDROMS for the Mississippi Department of Marine Resources and the U.S. Fish and Wildlife Service.

The original intent of the project was to map wetlands and uplands. However, the Minerals Management Service program was limited by the funding available and the cost of mapping. As a result, the

30 quads of coastal Alabama are not being mapped in this project; only wetlands are being mapped

for the whole project area.

The wetland habitat database will eventually consist of 84 quads mapped at a scale of 1:24,000

covering the coastal habitats from Chandeleur Islands, Louisiana to Cape San Bias, Florida. The

mapping protocol consists of data acquisition, stereoscopic photointerpretation, cartographictransfer,

and digitization in accordance with nationally accepted mapping standards and conventions. Other

important aspects of the project include the classification system, quality control, and peer review.

Photointerpretation by NWRC and NWI has been completed for the project area, and draft maps

have been produced. Groundtruthing for draft map review has been conducted for coastal Mississippi

and Florida by NWRC and NWI personnel. Corrections have been made to the Florida Panhandle

maps and they are being digitized with an expected completion by 1 January 1999. The Mississippi

coastal draft maps are still being reviewed and corrected by NWI quality control and regional staff.

Expected completion of the digital products for coastal Mississippi is 30 January 1999.

The mapping process follows standard operating procedures developed by the NWRC andthe NWI.

The photography is checked for quality, indexed, cut and prepped, and compiled by area (or estuary)

into photo-packs. The photointerpretation phase consists of applying the classification systemand

the delineation of the habitats as they are viewed through a stereoscope. The informationdelineated

on the photos is cartographically transferred to basemaps using a Zoom Transfer Scope. The base

maps for the project are standard USGS 1:24,000 scale quadrangles. Work is checked throughout

the process as part of quality control measures and cartographic integrity in accordance with

nationally accepted map standards and conventions. The completed quads are tablet digitized. The

digital data is maintained by quad (1:24,000) and available from NWRC in ArcJnfoTM format.

The NWI classification system, ClassjIcation of Wetlands and Deepwater Habitats of the

United States, Cowardin et aL, is being used to delineate the wetlands on the aerial photography.

Review of the draft maps was performed with the assistance of the NWRC, NWI and staff from

National Park Service-Gulf Islands National Seashore, U.S. Fish and Wildlife Service, Florida

Department of Environmental Protection, and other state and federal field offices. Draft maps were

distributed to staff of many public agencies, academia, and private individuals for peer review and

comment.

The National Wetlands Research Center was originally tasked with mapping the distribution of

seagrass habitat in the northern Gulf of Mexico as a result of a joint agreement with the

Environmental Protection Agency (EPA). As part of the Environmental Monitoring and Assessment

Program (EMAP), the mapping effort became an important baseline information component for a

comprehensive estuarine resource assessment.
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The original study targeted coastal areas along the Gulf of Mexico from Brownsville, Texas to

Anclote Key, Florida. Following the initial aerial photographic data acquisition mission from

Chandeleur Islands, Louisiana and points eastward along the gulf; EPA budget cuts and changes in

project goals restricted the coverage to areas between Louisiana and Anclote Key, Florida. As a

result, the available funding was not enough to include coastal Texas and Louisiana. Interests in

seagrass maps and data the project would generate led to the Minerals Management Service and

Florida Department of Environmental Protection to continue funding the mapping and digitizing.

In addition, the project could not have been accomplished without the active participation of staff from a host of federal, state, and public entities, including the U.S. Fish and Wildlife Service,

National Park Service, Dauphin Island Sea Lab, the National Marine Fisheries Service, and the Gulf

Coast Research Lab.

Seagrass habitat communities are considered to be of significant ecological, environmental, and

socioeconomical value. Urban development and natural impacts along the coast have produced

changes in these habitats, underscoring the importance of comprehensive assessments and research.

The seagrasses are distributed throughout a range of areas under a variety of ecological conditions.

The habitats can be described as either continuous or patchy beds of varying species and densities.

They are typically found in protected or low wave energy of relatively shallow waters, behind barrier

islands, or estuaries with low turbidity. Seagrass beds are nursery habitat for a host of fish,

microorganisms, and invertebrates. Seagrass is also an important food source for waterfowl. The

Chandeleur Islands, located along a major migratory corridor for wintering duck populations, are

characterized as having some of the most dense and productive seagrass beds remaining along the

Gulf Coast. Seagrasses function as a water quality indicator since they show responses to pollutants,

algal blooms, arid other hydrologic events. Additionally, seagrasses reduce the erosion of valuable

sediment by helping to stabilize substrates subject to tidal and/or wave energy. The most commonly

found species of seagrasses present in the Northern Gulf of Mexico are Halodule wrightil

(shoalgrass), Thalassia testudinum (turtiegrass), Ruppia maritima (widgeongrass), Cymodocea

filformis (manatee grass), and various macroalgae. The extent and distribution of seagrass habitats

are critical for monitoring such a vital natural resource. Producing maps for different periods helps

to understand trends and changes in estuarine ecosystems.

The seagrass habitat database consists of 149 quads mapped at a scale of 1:24,000 covering the

coastal habitats from Chandeleur Islands, Louisiana to Anclote Key, Florida. The mapping protocol

consists of data acquisition, stereoscopic photointerpretation, cartographic transfer, and digitization

in accordance with nationally accepted mapping standards and conventions. Other important aspects of the protocol include the development ofa classification system, quality control, and peer review.

To date, final maps have been completed for Chandeleur Islands to St. Joseph Bay, Florida (Cape San Bias). Photointerpretation, map drafting, and groundtruthing are currently in progress for Apalachicola Bay through Anclote Keys, Florida. Digital data - ArclnfoTM format - is available for

Chandeieur Islands through St. Andrew Bay, Florida.

The process begins with the acquisition of large scale aerial photography from which the seagrass habitats can be determined. Natural color emulsion, 1:24,000 scale, flown by NASA-Stennis in 1992

(June and November) is the primary data source. The photography is checked for quality, indexed,
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cut and prepped, and compiled by area (or estuary) into photo-packs. In most cases, only quads for

areas where seagrass is detectable on the aerial photography have been mapped. The

photointerpretation phase consists of development of a classification system and the delineation of

the habitats as they are viewed through a stereoscope. The information delineated on the photos is

cartographically transferred to basemaps using a Zoom Transfer Scope. Work is checked throughout

the process as part of quality control measures and cartographic integrity in accordance with

nationally accepted map standards and conventions. The completed quads are tablet digitized. The

digital data is maintained by quad (1:24k) and available from NWRC in ArclnfoTM format.

The classification system was designed to indicate the presence of either continuous or patchy

seagrass. In addition, the shoreline is delineated distinguishing land from either water or seagrass.

Land can be defined as any upland, irregularly flooded habitat, or the extent of vegetated (nonseagrass) cover. There are two classes of open water: RIV (riverine, fresh water) and EST (estuarine

or marine open water), and five classes of seagrass habitats. In the seagrass category, there are four

classes of patchy habitat based on percent ground cover (grass patch versus bare ground), ranging

from very sparse to dense: PSG1 (up to l0%very sparse), PSG2 (l5-40%sparse), PSG3 (45-

70%moderate), and PSG4 (75-95% dense); and one class of continuous seagrass habitat, CSG

(95 to 100% cover). No seagrass density distinction was made in the continuous class. Macroalgae

(ALG) was delineated only in those cases where field verification ofseagrass habitat resulted in the

identification of algae.

Groundtruthing was performed throughout the mappingprocess. It included the participation of field

staff from National Park Service-Gulf Islands National Seashore, U.S. Fish and Wildlife Service,

Dauphin Island Sea Lab consortium, Florida Department of Environmental Protection, and other

state and federal field offices. Draft maps were distributed to project sponsors and to staff of many

public agencies, academia, and private individuals for review. Any comments were evaluated and

corrections made to the maps. Final maps were produced in August and September 1998. Digitizing

was completed in October 1998. The digital data has been delivered to the Florida Department of

Environmental Protection's Marine Research Institute for inclusion in the MMS sponsored Gulfwide Information System, and is available through the data server at the National Wetlands Research

Center.
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DEVELOPMENT AND IMPLEMENTATION OF THE NORTHEASTERN GULF OF

MEXICO COASTAL CHARACTERIZATION AND DATA INFORMATION

MANAGEMENT SYSTEM AND DATA TRANSFER COMPUTER DEMONSTRATION

Mr. William R. Jones

Ms. Helena Schaefer

USGS, National Wetlands Research Center

In the 1 98Os, as oil and gas leasing was increasing, two characterization studies were conducted

along the northeastern Gulf of Mexico and the Mississippi Deltaic Plainto identify natural resources

and socioeconomic infrastructures that may be affected by proposed oil and gas activities. The

studies involved the collection, creation, and organization of data sets that identify sensitive areas

that could be threatened in the event of a catastrophic occurrence. The National Wetlands Research

Center is updating these two studies with the Northeastern Gulf of Mexico Coastal and Marine

Ecosystem Program: Coastal Characterization study. The area is defined as the region from the

Chandeleur Islands of Louisiana to Apalachicola Bay, Florida, which includes all coastal

counties/parishes and extends offshore to the federal leasing boundary. The project involved the

collection, organization, and analysis of existing databases, the creation ofnew data, and updating

of old data sets. The primary focus of the current characterization is on updating the two previous

characterization studies for this particular area, the Mississippi Deltaic Plain Region and the

Northeastern Gulf of Mexico Coast. This collection of data sets will facilitate the understanding of

this ecosystem's functioning role, especially those areas sensitive to environmental impacts from the

outer continental shelf oil and gas development.

The study had two primary objectives: developing an electronically accessible database, and creating

a live bottom "Community Profile." The first objective has resulted in the creation of Northeastern

Gulf of Mexico Coastal Characterization and Data Information Management System. The primary

focus of this system is to organize and disseminate the aforementioned data sets. This would allow

users from federal, private, state, local, and other sources to access, manipulate, and use the data and

information. The data sets have been and will be collected and incorporated into a digital database

that can be integrated into a functional GIS in the future. The second objective was to create a live

bottom community profile for the region. The report was contracted to Continental Shelf Associates,

mc, and will be available online through the data transfer system.

To meet the data transfer objective, the existing data sets first had to be located. The National

Wetlands Research Center contracted two U.S. Fish and Wildlife Service Ecological Service field

offices (Daphne, Alabama, and Panama City, Florida) to assist in the gathering of information on

known data sets; personnel from these two field offices searched for existing databases via the

Internet, or had familiarity ofnondigital databases for the region. Habitat databases housed at NWRC

were assessed and updated, and a submerged aquatic vegetation database was developed. Metadata

for these existing and new data sets are being developed, following the standards set forth by the

Federal Geographic Data Committee. Existing data sets were analyzed to ensure adherence to

procedures set forth by Executive Order 12906, "Coordinating Geographic Data Acquisition and
279

Access: The National Spatial Data Infrastructure." As data sets were located, the process of

developing a data dictionary was initialized. The data dictionary is a brief synopsis of a data set; the

dictionary includes the name of the data set, a brief description, geographic reference (name of or

coordinates), date of, format type, size of file, source of data, and a link to the data set (via the

Internet). Within the brief description, a link to the metadata may have been created, allowing access

to more information about the data set. This data dictionary was then formatted onto a website,

which is broken into three categories: habitat and submerged aquatic vegetation, natural resources

and socioeconomic features, and the live bottom community profile. The development of the website

will make the databases accessible to users who have an interest and concern for the gulf coast

region.

As of December 1998, NWRC has produced a user-friendly website that includes a data dictionary,

containing relative information for over 250 data sets. The beta version webpages are not yet

available on-line and are in the stages of quality control and refinement. Information about other data

sets will be added in the future as those data sets are developed, located, or converted into a digital

format. Additions to the data dictionary can be made simply by modifying the existing web pages.

Links to the actual data sets will be maintained to assure consistent accessibility.

In conclusion, the goals of data transfer system's objectives for the Northeastern Gulf of Mexico

Coastal and Marine Ecosystem Program are being achieved. An electronically accessible database

was created, consisting of a basic data dictionary about the known data sets. The approximate

number of data sets found for the region was 250 Links to digital databases for the region were

created, making data sharing and dissemination easier. Maintaining the links and searching for

unknown data sets remain priorities for the completion of the study.

William Jones has worked at the National Wetlands Research Center (NWRC) for eight years,

serving as a Geographer/GIS Specialist. Ivir. Jones received his B.A. in geography from the

University of Southern Mississippi. He has extensive experience with GIS software and coordinates

and manages GIS activities. Current projects include habitat mapping for the Coastal Wetlands

Planning, Protection, and Restoration Act Program and the submerged aquatic vegetation mapping

of the Northeastern Gulf of Mexico.

Helena Schaefer has worked at the NWRC for over four years, as a Geographer. Ms. Schaefer

received her B.A. in geography from the University of Texas at San Antonio. Current projects

involve serving as spatial data manager, metadata coordinator, and web designer of the NWRC' s

Spatial Data and Metadata server.
Introduction to the GulfCet Program: Study

Background, Philosophy, Research Elements,

and Design

Cetacean Habitat Associations in the

Northern Gulf of Mexico: An Overview

Environmental Patterns and Oceanographic

Processes during GulfCet II

Biological Oceanography and Trophic

Investigations in the Eastern Gulf of Mexico

Document Not Submitted

Abundance and Distribution of Cetaceans and

Sea Turtles in the Northern Gulf of Mexico

from GulfCet II Surveys

GulfCet II Acoustic Survey

Seabird Distribution and Habitat in the

Northern Gulf of Mexico

SESSION 2E

GULFCET IIMMS/BRD OFFSHORE INVESTIGATIONS OF MARINE

MAMMALS, SEA TURTLES, AND SEABIRDS IN THE GULF OF MEXICO

Co-Chairs: Dr. Robert M. Avent and Dr. Gary Brewer

Date: December 9, 1998

Presentation Author/Affiliation

Dr. William E Evans

Dr. Randall W. Davis

Texas A&M University at Galveston

Dr. William E Evans

Dr. Bernd Wfirsig

Mr. Joel Ortega-Ortiz

Dr. Randall W. Davis.

Texas A&M University at Galveston

Dr. D. C. Biggs

Texas A&M University

Dr. R. R. Leben

University of Colorado

Dr. John Wormuth

Texas A & M University

Dr. Keith D. Mullin

Mr. Wayne Hoggard

Southeast Fisheries Science Center

National Marine Fisheries Service, NOAA

Dr. Jeffrey C. Norris

Dr. William E Evans

Ms. Shannon Rankin

Marine Acoustics Lab

Texas A&M University at Galveston

Ms. Nancy Hess

Dr. Christine Ribic

University of Wisconsin, Madison

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INTRODUCTION TO THE GULFCET PROGRAM: STUDY BACKGROUND,

PHILOSOPHY, RESEARCH ELEMENTS, AND DESIGN

Dr. William E. Evans

Dr. Randall W. Davis

Texas A&M University at Galveston

BACKGROUND

The U.S. Department of the Interior's Minerals Management Service (MMS) is a client agency of

the BRD. The MMS has the responsibility for leasing, minerals exploration, and development of

submerged federal lands on the U.S. Outer Continental Shelf (OCS) under the provisions of the OCS

Lands Act Amendments of 1978 (92 Stat. 629). The National Environmental Policy Act of 1969

requires that all Federal Agencies use a systematic interdisciplinary approach that will ensure the

integrated use of the natural and social sciences in any planning and decision making that may have

an effect on the human environment.

As the Department of the Interior's bureau tasked with providing the scientific understanding and

technologies needed to support sound management and conservation of the Nation's biological

resources, the BRD administers this study.

The Endangered Species Act (ESA) of 1973, as amended, provides for the conservation of

endangered or threatened animal and plant species. The act requires that major federal actions do not

jeopardize the continued existence of listed species or result in the destruction or modification of

habitats determined to be critical. It also requires interagency consultation regarding the potential

effects of proposed activities on protected species in the northern Gulf of Mexico.

The Marine Mammal Protection Act (MMPA) of 1972, as amended, recognizes that certain species

and populations of marine mammals are, or may be, in danger of extinction or depletion as a result

of human activities, and establishes a national policy that marine mammal populations should be

protected and encouraged to develop to the greatest extent feasible, commensurate with sound

policies of resource management. The Secretaries of the Departments of the Interior and Commerce

are charged with all responsibility, authority, funding, and duties under the ESA and MMPA.

CETACEAN SURVEYS OF THE NORTHERN GULF PRIOR TO 1991

There are several sources of information on the distribution, abundance, and diversity of cetaceans

in the Gulf of Mexico (for a review see Jefferson and Shiro 1997). Cetacean stranding information

has been systematically collected since the late l97Os. A considerable amount of research has been

conducted on localized populations of bottlenose dolphins (Shane et al. 1986; Scott and Hansen

1989; Leatherwood and Reeves 1990). In U.S. Gulf of Mexico waters less than 200 m deep,

bottlenose dolphins and Atlantic spotted dolphins appear to be the most abundant cetacean species.

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284

Other directed studies, historic whaling records, animal strandings, and opportunistic sightings have

expanded the list of cetacean species known to occur in the Gulf (Jefferson and Shiro 1997).

Until recently, relatively little was known about cetaceans inhabiting deeper waters of the Gulf of

Mexico. From July 1989 through June 1990, NMFS conducted aerial surveys of cetaceans along the

continental slope of the north-central Gulf of Mexico in water ranging from 180-1,800 m deep

(Mullin et al. 1991; Muflin et al. 1994). The objectives were to: (1) examine cetacean species

diversity in the region, (2) determine the temporal and spatial distribution of cetaceans, and (3)

estimate relative abundance. Over 7,000 dolphins and whales were counted during 320 sightings.

Ranked from most to least commonly sighted groups, with percentage of total sightings, these were

(1)Risso's dolphins, 22%; sperm whales, 16%; bottlenose dolphins, 14%; Atlantic spotted dolphins,

13%; dwarf/pygmy sperm whales, 12%; striped/spinner/clymene dolphins, 9%; pantropical spotted

dolphins, 8%; beaked whales, 3%; and short-finned pilot whales, 2%. The remaining 2% of group

sightings were comprised of melon-headed/pygmy killer whales, false-killer whales, killer whales,

rough-toothed dolphins, a fin whale and a Bryde's/sei whale. Average sighting rate for the entire

study was 1.6 sightings per 100 transect km. Cetacean species had a wide spatial and temporal

distribution on the upper continental slope. Six species were sighted in every season (summer, fall,

winter, and spring) and two additional species were sighted in each season but winter. Twelve

species were sighted in summer, 10 in spring and fall, and only six in winter. Except for the shortfinned pilot whale, all species sighted more than once were sighted throughout the length (east-west)

of the study area. Sperm whales were found throughout the study area, but were concentrated in the

region near the Mississippi River delta.

THE GULFCET I PROGRAM: HOW MANY AND WHERE ARE THEY?

The most extensive survey of cetaceans in the offshore waters (100 to 2,000 m deep) of the northcentral and western Gulf of Mexico was conductedjointly by Texas A&M University and the NMFS,

Southeast Fisheries Science Center beginning in 1992 and called the GulfCet I Program (Davis and

Fargion 1996). This three year study provided synoptic information on the distribution and

abundance of cetaceans using both visual and acoustic survey techniques. It also provided limited

information on habitat preference.

During shipboard visual Surveys a total of 21,350 km of transect was visually surveyed during the

GulfCet I shipboard surveys. The cumulative survey effortfor each season was: spring = 13,507 km;

summer = 2,085 km; fall = 1,275 km; and winter 4,483 km It should be noted that

oceanographically there are only two seasons in the Gulf of Mexico, summer and winter. The spring,

summer and fall cruises are actually early, mid and late summer. The number of on-effortsightings

each season ranged from 14 during late summer to 509 during early summer. Nineteen cetacean

species were identified during 683 sightings made on-effort. Most of the survey effort occurred

during the early summer, with the least effort during the late summer

The bottlenose dolphin, pantropical spotted dolphin, and sperm whale were the most commonly

sighted species; each was sighted more than 70 times. Risso' s dolphin, clymene dolphin, dwarf

sperm whale, striped dolphin, and unidentified ziphiids were each sighted 21- 44 times, with the
285

other species sighted fewer than 20 times. Average group sizes ranged from 1.2 for pygmy sperm

whales and Cuvier's beaked whale to 141 for melon-headed whales. The estimated minimum

abundance of cetaceans inthe GulfCetI study areawas 19,198 (coefficient of variation {CV ]= 0.12)

animals.

Shipboard acoustic surveys were conducted concurrently with the visual surveys. A total of 12,219

km and 1,055 hours of acoustic effort was completed. On-effort acoustic sampling occurred 95% of

the time. A total of 487 acoustic contacts were recorded. Of that number, 124 contacts were from

12 identified species. Sperm whales were the most commonlyrecorded species, accounting for 56%

of identified contacts. The most commonly recorded small cetacean was the pantropical spotted

dolphin, with 22 contacts. A single recording of an unidentified baleen whale was made, probably

a sei or Bryde' s whale, based on its spectral characteristics. An additional 331 contacts were made

of unidentified dolphins at times when there was no visual effort, such as during poor weather and

at night. There were 30 contacts with unidentified cetaceans.These were typically pulsed signals that

did not sound like sperm whales or dolphins and were possibly either dwarf/pygmy sperm whales

or beaked whales. Also recorded were 19 unidentified biological contacts, probably shrimp

Approximately half of the species expected to occur in the Gulf as determined by Jeffersonand Shiro

(1997) were recorded, including the rarely recorded clymene and rough-toothed dolphins as well as

the first recording ever of Fraser's dolphin (Leatherwood et al. 1993).

A total of 67 sperm whale on-effort, acoustic contacts were recorded along 85 transect lines.

Assuming 7 3 individuals per group, the overall corrected mean sperm whale density was 2.041

individuals/1,000 km2 (SD = 2.38, n = 85).. Within the 154,621 km2 study area, the totalestimated

population of sperm whales is 316 individuals (265-377). On average, one sperm whale group was

detected every 161 km.

A total of 369 dolphin on-effort, acoustic contacts were made along the same 85 transect lines used

to estimate sperm whale abundance. On average, one dolphin group was detected every 31 km. The

mean dolphin contact density was 1,298 groups in the study area. Using a weighted mean of 28.3

animals/group, the overall mean dolphin density was 229 dolphins/l,000 km2. The total estimated

dolphin population within the study area was 36,760 animals (3 0,835-43,821).

A total of 49,960 km of aerial survey transect was visually sampled during eight aerial surveys. The

transect kilometers sampled by survey ranged from 5,330-6,592 km, and by season from 11,756-

12,942 km. In total, 351 cetacean groups were sighted on-effort. The number of sightings each

survey ranged from 24 to 61 for fall 1992 and winter 1994, respectively. By season the number of

sightings ranged from 49 to 109 for late summer and winter, respectively.

At least 17 cetacean species were identified during aerial surveys (each of these species was also

sighted during ship surveys). Seasonally, the number of species sighted ranged from 11 in the fall

to 15 in winter. Eight species were identified in all four seasons, two in three seasons, four in two

seasons and four in only one season. Five species, which were each sighted 20 or more times,

accounted for 71% of the identified sightings: bottlenose dolphins, pantropical spotted dolphins,

Risso' s dolphins, pygmy/dwarf sperm whales, arid sperm whales.
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Overall, there were an estimated 16,986 (CV = 0.14) cetaceans in the GulfCet I aerial survey study

area. There were an estimated 12,690 (CV = 0.23) cetaceans the first year and 20,669 (CV = 0.18)

the second. Most of the difference between years resulted from two winter and the two spring

estimates. In both cases, the point estimates were about twice as large the second year compared to

the first. Cetacean abundance was about the same in winter (21,894; CV = 0.27) and spring (19,215;

CV 0.25), a little less in summer (14,959; CV = 0.24), but two to three times lower in the fall

(6,051; CV = 0.32).

Pantropical spotted dolphins were the most abundant species in the aerial survey study area (5,251;

CV 0.22) followed by melon-headed whales (2,980; CV = 0.60), bottlenose dolphins (2,890; CV

= 0.20) and Risso's dolphins (1,214; CV 0.24). The sperm whale population was estimated to be

87 (CV 0.27) and pygmy/dwarf sperm whales, 176 (CV = 0.31). All the other deiphinid species

were represented by less than 1,000 individuals each, and balaenopterids and ziphiids, by less than

100 individuals each. Mean group sizes ranged from 315 for melon-headed whales to less than four

for pygmy/dwarf sperm whales, sperm whales and ziphiids.

The GulfCet I Program provided limited information on habitat preference, which showed the

strongest correlation of species distribution with ocean depth. However, this study failed to establish

strong correlation with other oceanographic variables such as sea surface temperature, salinity, water

column structure and distinctive features such as warm-core and cold-core eddies. This may have

resulted from the fact that: (1) the oceanography of the Gulf of Mexico is very dynamic with the

periodic intrusion of the Loop Current from the southeast and the formation of warm-core eddies that

move across the northern Gulf and (2) cetaceans are large, warm-blooded mammals whose wideranging movements are not physiologically constrained by water temperature or other hydrographic

features.

GULFCET II: OCEANOGRAPHIC AND BIOLOGICAL CORRELATES TO DISTRIBUTION

In the GulfCet II program, we continued our studies of cetaceans in the northern Gulf of Mexico to

determine their seasonal and geographic distribution in areas potentially affected by oil and gas

activities now or in the future. This program included systematic aerial surveys and shipboard visual

and acoustic surveys to document cetacean, sea bird and sea turtle populations. This work was

accompanied by data acquisition designed to further characterize habitat and reveal cetacean-habitat

associations. This study was intended as an areal and temporal extension of the GulfCet I Program.

The study area included the entire continental slope of the northern Gulf of Mexico (i.e., the

continental slope north of 26° N latitude) between the 100 and 2,000 m isobaths and was extended

into the MIMS Eastern Planning area. The specific objectives of the study were to

1. Obtain data on temporal and spatial patterns of distribution and minimum abundance of

cetaceans and sea birds using visual line-transect and cetaceans using acoustic survey

techniques directly comparable to those used in previous surveys. This included incidental

sightings of sea turtles.
287

2. Identify possible associations between cetacean and sea bird high-use habitats and the ocean

environment, and attempt to explain any relationships which appear to be important to their

distributions.

Objective 1 was a continuation of surveys in the north-central and western Gulf that began during

the GulfCet I program and extended into MMS's Eastern Planning Area. To accomplish this

objective, we conducted aerial surveys and simultaneous shipboard visual and acoustic surveys using

line-transect methods. We hypothesized that cetaceans and possibly birds and sea turtles were nonuniformly distributed (which we confirmed during GulfCet I) and that their distributions were related

to variability in prey availability and physical oceanographic features in the marine environment.

To characterize habitat (Objective 2), we used a multidisciplinary approach and included physical

features (i.e., sea surface temperature, ocean depth, oceanographic features such as warm-core and

cold-core eddies, bottom topography) as well as biological features such as prey availability. We

hypothesized that the distribution and abundance of marine mammals in the northern Gulf of Mexico

were positively correlated with spatial arid temporal variations in regional food stocks of

zooplankton and micronekton. These food stocks are concentrated in nutrient-rich areas offshore

from the Mississippi River, within cold-core eddies, or along the edge of warm-core eddies. To test

this hypothesis we conducted focal cruises designed to transect the main oceanographic feature off

of the mouth of the Mississippi River. These features were detected near real time using

TOPEX/Poseidon radar altimetry images to detect cold core eddies or cyclones and warm core eddies

(anticyclones). In addition to the standard visual and acoustic survey techniques used in GulfCet I,

we collected synoptic data on several oceanographic features measuring salinity and temperature as

a function of depth, measures of biomass using acoustic backscatter from the Acoustic Doppler

Current Profiler and standard net tows using a Isaacs-Kidd midwater trawl (IKMT) with a mouth

area of 6 m2 and two multiple opening and closing nekton environmental sampling system

(MOCNESS), one with mouth area of 4m2 and one with 1m2.

REFERENCES

Davis, R.W. and U.S. Fargion, eds. 1996. Distribution and abundance of marine mammals in the

north-central and western Gulf of Mexico: Final Report. Volume II: Technical Report. OCS

Study MMS 96-0027. U.S. Dept. of the Interior, Minerals Mgmt. Service, Gulf of Mexico OCS

Region, New Orleans, LA. 357 pp.

Fritts, T.H., Irvine, AB, Jennings, R.D., Collum, L.A., Hoffthan, W. and M.A. McGehee. 1983.

Turtles, Birds, and Mammals in the Northern Gulf of Mexico and Nearby Atlantic Waters.

FWS/OBS-82/65. Division of Biological Services, U.S. Fish and Wildlife Service, U.S. Dept.

of Interior, Washington, D.C. 347 pp.

Jefferson, T.A and Shiro, A.J. 1997. Distribution of cetaceans in the offshore Gulf of Mexico.

Mammal. Rev. 27:27-50.
288

Leatherwood, S. and R.R. Reeves, eds. 1990. The bottlenose dolphin. Academic Press, San Diego,

653 pp.

Leatherwood, S., Jefferson, T.A., Norris, J.C., Stevens, W.E., Hansen, L.J. and Mullin, K.D. 1993.

Occurrence and sounds of Fraser's Dolphins (Lagenodeiphis Hosei) in the Gulf of Mexico.

Texas J. Sci. 45:349-354.

Mullin, K., Hoggard, W., Roden, C., Logoefener, R., Rogers, C., and Taggart, B. 199 1.Cetaceans

on the upper continental slope in the north-central Gulf of Mexico. OCS Study/MMS 9 1-0027.

U.S. Dept. of the Interior, Minerals Mgrnt. Service, Gulf of Mexico RCS Regional Office, New

Orleans, LA. 108 pp.

Mullin, K.D., Hoggard, W., Roden, C.L., Logoefener, R.R., Rogers, C.M, and Taggart, B. 1994.

Cetaceans on the upper continental slope in the north-central Gulf of Mexico. Fish. Bull. 92:773-

786.

Schmidly, D. J. 1981. Marine mammals of the southeastern United States coast and the Gulf of

Mexico. U.S. Fish and Wildlife Service, Office of Biological Service, Washington, DC,

FWS/OBS-80/41. 163 pp.

Scott, G.P. andL.J. Hansen. 1989. Report of the Southeast Fisheries Science Center marine mammal

program review, 2-3 May, 1989. NOAA Technical Memorandum NMFS-SEFC-235. National

Marine Fisheries Service, 75 Virginia Beach Drive, Miami, FL. 81 pp.

Scott, G.P., D.M. Burn, L.J. Hansen, and R.E. Owen. 1989. Estimates of bottlenose dolphin

abundance in the Gulf of Mexico from regional aerial surveys. Unpubl. Report. 7Opp.

Shane, S.H., R.S. Wells, B. Wursig. 1986. Ecology, behavior and social organization of the

bottlenose dolphin: A review. Marine Mammal Science 2:34-63.

Dr. William Evans is a retired professor in the Departments of Marine Biology and Marine Science

at Texas A & M University at Galveston. He served as Under Secretary of Commerce for Oceans

and Atmosphere and Administrator of NOAA from 1988-1989, President Texas Institute of

Oceanography in 1991, and Deputy Manager for the MIVIS-TAMU GulfCet II program from 1996-

1997. He received his Ph.D. in 1975 from the University of California at Los Angeles.

Dr. Randall Davis is a Professor in the Departments of Wildlife and Fisheries Sciences and Marine

Biology at Texas A & M University. He has served as GulfCet II Program Manager and co-PI for

the GulfCet II program. He received his Ph.D. in physiology from the University of California, San

Diego in 1980.
CETACEAN HABITAT ASSOCIATIONS IN THE NORTHERN

GULF OF MEXICO: AN OVERVIEW

Dr. William E. Evans

Dr. Bernd Wursig

Mr. Joel Ortega-Ortiz

Dr. Randall W. Davis

Texas A&M University at Galveston

Objectives of the GulfCet program were to identifr possible associations between cetacean high-use

habitats and the ocean environment, and thereby explain relationships that appear to be important

in cetacean distribution. To accomplish this objective, cetacean distribution data gathered on 14

surveys in the northern Gulf of Mexico were compared with oceanographic features as identified

from shipboard and remote sensing data.

During GulfCet I, from 1992-1994, 11 cruises were conducted in the northwestern and northcentral

Gulf of Mexico. GulfCet II, from 1996-1997, included four cruises in the northeast Gulf of Mexico.

The cruises were conducted by Texas A & M University (TAMU) and the National Marine Fisheries

Service-Southeast Fisheries Sciences Center (NMFS-SEFSC).

During these cruises, line transect data were collected by observers using 25 X 150 "Big Eye"

binoculars mounted on the ship's flying bridge. Effort was conducted during daylight hours, weather

permitting (i.e., no rain, Beaufort Sea State < 5), using standard vessel survey data collection

methods for cetaceans (Buckland et al. 1993). Vessel speed was usually 15 kin/hr but varied with

sea conditions.

The surveyed area was divided into six categories depending on oceanographic features: anticyclone,

anticyclone edge, cyclone, cyclone edge, confluence, and other. The method used to delimit the

oceanographic features varied by cruise. For GuifCet I TAMU cruises, the features were identified

using sea surface height anomaly (SSH anomaly) computed from satellite data by the Center for

Astrophysics Research University of Colorado. SSH anomaly> 10 cm was considered as an

anticyclone, SSH anomaly < -10 cm was considered as a cyclone. No confluence areas were

identified for these cruises, and any area not labeled as anticyclone or cyclone was considered as

"other." The features for the GulfCet I NMFS cruises were determined using the same criteria

described above, as well as depth of the 15°C isotherm obtained from Conductivity-TemperatureDepth (CTD) casts and expendable bathythermograph (XBT) data registered from the ship. The S SH

anomaly estimated from satellite data is not as accurate for the northeastern as it is for the north

central and northwestern Gulf of Mexico. It reflects the spatially variable position of the Loop

Current, as well as the variable position of the cyclone-anticyclone modon pairs frequently found in

association. The temporal and spatial variability in the geographic locations of both make it

problematic to assign a single SSH model mean to the northeastern Gulf. As a consequence, the use

of the 15°C isotherm was necessary during cruises where surveys were conducted in the northeast

Gulf of Mexico.

289
290

The features for GulfCet II cruises were determined using dynamic height relative to 800 m depth

estimated from shipboard-collected CTD and XBT data. For the Gyre 96G06 (October 1996) cruise,

any area with dynamic height < 100 dynamic centimeters (dyn cm) was considered as acyclone. The

areas with dynamic height> 125 dyn cm were considered as anticyclone. An area of confluence was

observed between the cyclone-anticyclone pair (26.2-26.6° N Lat. by 86.587.50 W Long.).

For the Gyre 97G08 (August 1997) cruise, the cyclone was defined as < 105 dyn cm and the

anticyclone as> 130 dyn cm. A confluence area was observed from 26.9-27.9° N Lat. by 86.3-87.8°

WLong.

A more detailed explanation of the oceanographic processes and features present in the area during

the GulfCet II cruises is included in the abstract by Biggs and Leben for these proceedings.

The edges of both anticyclone and cyclone were determined using the magnitude and direction of

geostrophic velocity. Any area located within the anticyclone or cyclone dynamic height boundaries,

with a geostrophic velocity> 45 cnilsec was considered as an edge. The areas between features with

geostrophic velocities> 45 cmlsec were considered as confluence. Any area that could not be placed

in any of the previous features was considered as "other."

To compare the presence/absence of cetaceans in the different oceanographic features of the study

area, transect effort was divided into 18.52 km-long (10 nautical mile) units named effort-bins. If,

during the division of the transect effort, the last bin of a transect line was less than 9.25 km. it was

added to the previous bin. If it was greater than 9.25 km, it was considered as a separate bin. A total

of 3,779 effort-bins were obtained from the transect effort of 14 cruises. The mean effort-bin length

was 16.6 km and the standard deviation was 5.61. Each bin was assigned to a particular

oceanographic feature.

Sightings registered during transect effort were assigned to their corresponding effort-bin, and binary

variables were created to register the presence or absence of sightings within each bin for the

following species or groups of species:

CETACEAN - any species

SPERM WHALE - Physeter macrocephalus

STENELLAS - Oceanic dolphins of the genus Stenella: S. attenuata, S. clymene, S.

coeruleoalba, and S. ion girostris

Most species of cetaceans of the Gulf of Mexico occur in water deeper than 200 m, with the

exception of Atlantic spotted dolphins and bottlenose dolphins, which inhabit the continental shelf

(Mullin et al. 1994, Davis et al. 1998). For this reason, only the offshore effort-bins (n 1985) were

used for habitat association analyses.

Chi-squared analyses were used to test the hypothesis that the presence or absence of cetaceans was

independent from depth regions or oceanographic features in the study area. Friedman-Tukey

deviates were calculated to determine cells contributing significantly to the chi-squared values. The

results of the significant tests (p<O.O5) are discussed below.
291

Sightings of cetaceans were not independent from depth regions. Presence of cetaceans was higher

than expected over the upper shelf and lower than expected over the abyssal region.

Presence of cetaceans was not independent from the six oceanographic features.

Cetaceans were sighted more frequently than expected in the cyclone, and less frequently than

expected in the anticyclone.

Oceanic Stenella presence was higher than expected in the cyclone and cyclone edge, and less than

expected in the anticyclone and "other."

The presence of sperm whales was also not independent from the six oceanographic features. Sperm

whales were seen more often than expected in the edge of the anticyclone and less often than

expected in the anticyclone and edge of the cyclone.

Our MMSINBS sponsored study has given us the opportunity to compare cetacean occurrence and

highly detailed oceanographic information from a large database of 14 ship-based surveys. We

conclude that cetaceans are not randomly distributed in the northern Gulf of Mexico; they are

influenced both by bottom depth and by the presence ofmesoscale hydrographic features. Cetaceans

tend to be associated with cyclonic features and the areas of confluence between cyclone-anticyclone

pairs.

An important step for the future is to link knowledge of cetacean occurrence and movement patterns

with detailed oceanographic studies. This can be accomplished by photoidentification and satellite

telemetry, for example; and will provide infonnation on habitat partitioning by species and species

groups.

ACKNOWLEDGMENTS

We are grateful to the many volunteer observers who participated in the TAMIJ surveys. We thank

Dr. Keith Mullin for providing the data from NMFS cruises, Dr. Douglas Biggs and Mr. Patrick

Ressler for providing the shipboard oceanographic data for GulfCet II cruises, Dr. Robert Leben and

Joshua Rigler for providing the satellite SSH data, and Dr. Christine Ribic and Ms. Nancy Hess for

their advice on the statistical analyses. This ongoing research is supported by the USGS Biological

Resources Division and by the US Minerals Management Service under USGS BRD contract 1445-

C 109-96-004 to Texas A & M.

REFERENCES

Buckland, S.T., D.R. Anderson, K.P. Burnham, andJ.L. Laake. 1993. Distance sampling: estimating

abundance of biological populations. Chapman and Hall, London. 446 pp.

Davis, R.W., G.S. Fargion, N. May, T.D. Leming, M. Baumgartner, W.R. Evans, L.J. Hansen,

K. Mullin. 1998. Physical habitat of cetaceans along the continental slope in the north-central

and western Gulf of Mexico. Marine Mammal Science 14: 490-507.
292

Mullin, K.D., W. Hoggard, C.L. Roden, R.R. Lohoefener, C.M. Rogers, and B. Taggart. 1994.

Cetaceans on the upper continental slope in the north central Gulf of Mexico. Fishery Bulletin

92:773-786.

Dr. William Evans is a retired professor in the Departments of Marine Biology and Marine Science

at Texas A & M University at Galveston. He served as Under Secretary of Commerce for Oceans

and Atmosphere and Administrator of NOAA from 1988-1989, President Texas Institute of

Oceanography in 1991, and Deputy Manager for the MMS-TAMU GulfCet II program from 1996-

1997. He received his Ph.D. in 1975 from the University of California at Los Angeles.

Dr. Bemd Würsig is a professor in the Departments of Wildlife and Fisheries Sciences and Marine

Biology at Texas A & M University. He served as Deputy-Principal Investigator for GulfCet I and

as co-Principal Investigator for ship board surveys and behavior for GulfCet II. He received his Ph.D.

in ecology and evolution in 1978 from the State University of New York at Stony Brook.

Joel Ortega-Ortiz is a research assistant at Texas A & M University where he is currently pursuing

a Ph.D. in wildlife and fisheries sciences. He received his M.Sc. in biological oceanography in 1996

from the Universidad Nacional Autónoma de Mexico.

Dr. Randall Davis is a professor in the Departments of Wildlife and Fisheries Sciences and Marine

Biology at Texas A & M University. He has served as GulfCet TI Program Manager and co-PT for

the GulfCet II program. He received his Ph.D. in physiology from the University of California, San

Diego in 1980.

ENVIRONMENTAL PATTERNS AND OCEANOGRAPHIC

PROCESSES DURING GULFCET II

Dr. flC. Biggs

Texas A&M University

Dr. R.R. Leben

University of Colorado

Four cruises of R1V Oregon-Il and RTV Gyre were combined with tandem remote sensing of sea

surface height using the Topex/Poseidon and ERS-2 altimeters to characterize the hydrographic

regime of the northeast Gulf ofMexico for the GulfCet II program. In May-June 1996, October 1996,

May-June 1997, and August 1997, the two ships dropped 560 expendable bathythermographs

(XBTs) which profiled the temperature structure of the upper 760 m. These XBT stations were

supplemented with conductivity-temperature-depth (CTD) and bottle stations, at 32 additional
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locations. The spatial distribution of the stations is summarized cruise-by-cruise in Figure 2E. 1. The

early summer cruises focused their survey work between 890 W and 850 W, from water depths of

100 m to 1,000 m, because this region of the continental slope is the region which MIMS has

designated its "Eastern Planning Area." The cruises later in the summer also surveyed this region

of the slope, but in addition they surveyed farther seaward, within a deepwater "focal area" where

altimetry data that were processed in near real-time at the University of Colorado Center for

Astrodynamics Research (CCAR) indicated there was a "modon" circulation pair consisting of a

mesoseale cold-core eddy (cyclone) and a warm-core eddy (anticyclone).

Figure 2E. 1. Location ofhydrographic stations made by RIV Gyre and R'V Oregon-Ilduring four

GulfCet II cruises that surveyed the NE Gulf of Mexico in early and late summer

1996 and early and mid summer 1997.
294

The altimetry data show that a broad area of cyclonic circulation was located in the NE Gulf

throughout calendar year 1996. This showed up in weekly and monthly altimetry maps as a region

of consistently negative sea surface height anomaly (S SH), depressed 20 cm or more relative to the

climatological mean surface. This cold-core feature was seen January through September in the

region 27-29° N, 88-84° W, even though for much of the year, the northern edge of the Loop

Current extended north of 25° N and even though the Loop Current shed two large anticyclonic

eddies during 1996. By October, the cyclone was centered 27-28° N, 87-89° W, roughly halfway

between the Mississippi River delta and the NW edge of Loop Current Eddy C. The late summer

dynamic topography of this cyclone- anticyclone eddy pair, as determined from ship survey lines,

is shown in Figure 2E.2. The 62 dynamic cm difference in height between the interior of the cyclone

Figure 2E.2. Dynamic topography (cm, 0 m to 800 m) of the deepwater focal area, as deterniined

from 152 hydrographic stations made on R'V Gyre cruise 96G-06.
295

(88 dyn cm) and anticyclone (150 dyn cm) was manifest as a flow confluence between the two

features in which upper layer geostrophic volume transport was 24 x 106 m3 s_I (24 Sverdrups).

In mid-summer 1997, R/V Gyre cruise 97G-08 surveyed another deepwater cyclone-anticyclone pair.

This time, the cyclone was centered over the DeSoto Canyon and to the NE of Loop Current Eddy

E. The dynamic topography, as determined from ship survey lines, is shown in Figure 2E.3. The 84

dynamic cm difference in height between the interior of the cyclone (92 dyn cm) and anticyclone

(176 dyn cm) was manifest as a flow confluence between the two features in which upper layer

geostrophic volume transport was 31 x 106 m3 s_i (31 Sverdrups). Underway sampling of surface

temperature, salinity, and chlorophyll concentrations while the vessel criss-crossed the confluence

Figure 2E.3. Dynamic topography (cm, 0 m to 800 m) of the deepwater focal area, as determined

from 107 hydrographic stations made on RJV Gyre cruise 970-08.
296

region showed that low salinity, high chlorophyll river water was entrained from off shelf and then

transported anticlockwise around the periphery of the cyclone.

From subsurface sampling at CTD and bottle stations, we learned that there was a highly predictable

negative first order relationship between temperature <220 C and nitrate concentration (Figure

2E.4). Temperature could thus be used as a proxy for nitrate concentration, and in particular the

depth of the 19°C isotherm was a good estimation of the depth of the 10 uM nitrate concentration.

Within the cyclone, the nitracline was domed 40-60 m shallower than in Loop Current Eddy C or

Figure 2E.4. Property-property plot of bottle data from RJV Gyre cruise 96G-06, illustrating how

depth of the 190 C isotherm can be used as a proxy for 10 uM nitrate concentration.
297

Eddy B. Because this doming facilitated a higher flux of new nitrogen into surface waters in cyclone

than in anticyclone, the cyclone had locally higher chlorophyll concentrations and also locally higher

standing stocks of plankton and nekton (see summary by Wormuth et al., this session). The higher

biological productivity of the cyclone apparently also supported local aggregations of squid, which

prey on the rich midwater fish fauna of the cyclones and which in turn are eaten as food by dolphins

and sperm whales.

The four shipboard surveys also found that 19°C depth was locally shallow at the shelf-slope break,

particularly in the early summer. Unfortunately, we do not have surface chlorophyll data for either

of the two early summer cruises, so we do not know whether this shelf edge upwelling was expressed

at the surface as locally high primary production and/or surface chlorophyll concentration. In mid

summer the shelf-edge doming of the 19°C depth was not as strong, and the shelf-slope break was

not marked by locally high surface chlorophyll. On the late summer cruise, we found no evidence

for shelf edge upwelling from either surface or subsurface data.

Oceanographic habitat for all GulfCet I &II aerial and GulfCet I shipboard surveys have also been

characterized using coincident altimetry from the TOPEX/POSEIDON and ERS-1 & 2 satellites.

Daily fields of sea surface height topography on a 1/4 degree grid were estimated by adding the

height anomaly fields, interpolated from the available along-track altimeter data, to a model mean

surface. To quantify the relationship between sightings and the remotely sensed physical

environment, the sea surface height, geostrophic velocity magnitude, relative vorticity and horizontal

radius of curvature were computed at each sighting location from the gridded height fields.

Randomization tests are in progress to test the null hypothesis that the marine mammals are sightings

are purely by chance and unrelated to the ocean environment. These tests are very effective in

identifying significant statistical relationships for small, sparse or nonrandom sample sets and take

full advantage of the over six years of satellite altimetry.

ACKNOWLEDGMENT

This ongoing research is supported by the USGS Biological Resources Division and by the US

Minerals Management Service under USGS BRD contract 1445-C 109-96-004.

Dr. Douglas Biggs is a Professor in the Department of Oceanography at Texas A&M University. He

served as Principal Investigator for the MMS-TAMTJ Ship-Of-Opportunity Hydrographic Program

1989-1995, and as co-Principal Investigator for hydrographic fieldwork for the MMS-TAIV[EJ

GulfCet II program, 1996-1997. He received the Ph.D. in oceanography in 1976 from the MITWHOI Joint Program.

Dr. Robert Leben is an Associate Research Professor in the Department of Aerospace Engineering

Sciences at the University of Colorado, Boulder, where he received his Ph.D. in 1986. His areas of
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research interest are satellite oceanography and computational fluid dynamics, and he served co-PI

in the MMS-TAMTJ GulfCet II program.

ABUNDANCE AND DISTRIBUTION OF CETACEANS AND SEA TURTLES IN THE

NORTHERN GULF OF MEXICO FROM GULFCET II SURVEYS

Dr. Keith D. Mullin

Mr. Wayne Hoggard

Southeast Fisheries Science Center

National Marine Fisheries Service, NOAA

Pascagoula, Mississippi

NTRODUCTION

GulfCet II surveys were designed to study cetacean and sea turtle diversity, abundances, and spatiotemporal distributions in the northeastern Gulf of Mexico and were a continuation of the GulfCet

I surveys of the north-central and northwestern Gulf (Hansen et al. 1996). The surveys focused on

continental slope waters (100-2,000 m) between Mobile Bay and Tampa Bay and a portion ofthe

continental shelf adjacent to the western Florida Panhandle. The continental shelf area overlapped

the Minerals Management Service Destin Dome leasing area.

Shipboard surveys were conducted in the northeastern Gulf during the spring, summer, and late

summer. Spring ship surveys included oceanic waters of the entireU.S. Gulf (waters >100 m deep)

and overlapped the GulfCet I study area. Aerial surveys were designed seasonally to complement the

ship surveys and were conducted during both the warm (sunmier) and cold (winter) oceanographic

seasons over two years. The primary objectives of both the aerial and ship surveys were to

(1) estimate the minimum numbers of cetaceans and sea turtles (aerial surveys only) of each species

in the study area, (2) determine when each species is present in the study area, (3) establish

repeatable baseline estimates of cetacean and sea turtle abundances to compare with future estimates,

and (4) determine how species are distributed in the study area.

METHODS

Ship SurveysLine-transect data were collected using standard ship survey methods similar to those

used during GulfCet I (Buckland et al. 1993, Hansen et al. 1996). Two observers searched for

cetaceans during daylight hours using 25X "bigeye" binoculars mounted on the ship's flying bridge.

The third observer searched near the ship using unaided eye and recorded data which included

position, species, group-size, bearing and radial distance of a sighting, and environmental conditions.

Spring ship surveys were conducted from NOAA Ship Oregon II in 1996 and 1997 from mid-April

to early June. Each year, Legs 1 and 2 were conducted along a predetermined trackline throughout
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the oceanic U.S. Gulf whereas Leg 3 focused on the northeastern Gulf. During late summer 1996

(10-29 October) and summer 1997 (4-22 August), the FUV Gyre was used to conduct line-transect

surveys in the north-central and northeastern Gulf. Two areas were surveyed, the northeastern Gulf

and a focal area in the north-central Gulf that was chosen based on oceanographic considerations.

The focal area was sampled by five tracklines oriented NW-SE, south of Louisiana and Mississippi.

In the late summer and summer, tracklines were transited 24-hours per day to accommodate acoustic

sampling.

Aerial SurveysAerial surveys of the northeastern Gulf were conducted during summer 1996 and

1997, and winter 1997 and 1998. Seasonal sampling intensity during aerial surveys of the

northeastern Gulf was similar to that expended during GulfCet I. Systematic transects with a random

start that generally crossed isobaths orthogonally were uniformly spaced throughout the aerial survey

area. Each season the goal was to survey 58 transect lines totaling 6,133 km of on-transect effort,

including 42 transect lines (total of 5,220 km) on the continental slope (waters 100-2,000 m deep)

and 16 transect lines on the continental shelf (waters <100 m deep).

A DeHavilland DHC-6 Twin-Otter with large concave windows on each side of the fuselage was

used to survey transects. A window of 45-days and about 100 flight hours were allocated for each

seasonal survey. Surveys were conducted from an altitude of 229 m (750 feet) and at a speed of 204

km!hour (110 knots). A pilot, co-pilot, and four observers participated in each flight. Data were

entered on a computer. A suite of data characterizing survey conditions (e.g., sea state), effort status,

and observer positions were updated throughout the day. When a cetacean group was sighted, the

sighting angle was noted, a dye-marker was usually dropped to mark the position, and the aircraft

was diverted to circle the group. Before continuing the transect, the species was identifiedand groupsize was estimated.

Density and abundance estimates for cetacean and sea turtle species were made for each study area

using line-transect methods (Buckland et al. 1993, Laake et al. 1993). GulfCet II study areas include

the northeastern Gulf continental shelf, the northeastern Gulf continental slope, the oceanic northern

Gulf, and the GulfCet I study area.

RESULTS

Ship SurveysDuring spring surveys, 11,631 transect km were surveyed, 455 cetacean groups were

sighted on-effort, and at least 20 species were sighted. The most commonly sighted species in waters

>100 m deep were pantropical spotted dolphins (106 sightings), bottlenose dolphins (45), Risso's

dolphins (47), sperm whales (36), and dwarf/pygmy sperm whales (29). In waters >100 m deep,

these five species comprised about 65% of the identified sightings. Two sightings were of groups

that were larger than any previously sighted in the Gulf of Mexico. One sighting had an estimated

750 spinner dolphins and the other, 650 pantropical spotted dolphins. Group-sizes of other species

were more typical of previous years. Cetaceans were encountered in all areas of the Gulf surveyed.

Sightings were more common in some areas than others (e.g., near the Mississippi River delta).

Bottlenose dolphins and Atlantic spotted dolphins were the only species sighted in continental shelf

waters.
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During late summer and summer, 1,613 and 1,670 transect kin, respectively, were surveyed visually

in the northeastern Gulf. At least eight species were seen in 82 on-effort sightings in the northeastern

Gulf. Pantropical spotted dolphins and bottlenose dolphins were the most common species sighted

in waters >100 m deep. Bottlenose dolphins and Atlantic spotted dolphins were the only species

sighted in continental shelf waters.

Aerial Surveys - During both summer surveys, the 58 proposed transect lines were completed (6,133

km). Due to poor weather, only 80% of the proposed effort was completed during the winter surveys.

Previous studies of cetaceans in the northern Gulf indicate that only bottlenose dolphins and Atlantic

spotted dolphins are commonly found on the continental shelf, whereas other species occur in

oceanic waters. Results of the GulfCet II aerial surveys agreed with this (Table 2E. 1). On the

continental slope, at least 16 species of cetaceans were identified. Overall, pantropical spotted

dolphins were the most abundant species on the continental slope, followed by spinner dolphins,

bottlenose dolphins, clymene dolphins, and striped dolphins The abundance of some species

appeared to be different for summer and winter. For summer and winter, respectively, the

abundances of dwarf/pygmy sperm whales were 331(0.33) and 36 (0.68), pantropical spotted

dolphin abundances were 18,020(0.29) and 8,226 (0.36), and Risso's dolphin abundances were 761

(0.51) and 2,007 (0.39). Aerial survey sighting rates of cetacean groups on the continental slope of

the northeastern Gulf were about two times greater than the overall group sighting rate found during

GulfCet I aerial surveys of the northwestern Gulf slope (Hansen et al. 1996). In general, cetacean

groups were sighted throughout the entire study area. Certain species tended to be found over waters

of different depths. Group-sizes varied among species.

Sea turtles were sighted 163 times. Continental shelf sightings were as follows: loggerheads - 85

turtles, Kemp's ridley - 3, unidentified chelonids - 10, and leatberbacks - 4. Continental slope

sightings consisted of 28 leatherbacks, 27 loggerheads (25 during winter), and two chelonids.

Leatherbacks were generally sighted in the northern half of the study area during summer, but during

winter were concentrated in an area west of Tampa in the southern half of the study area.

SUMMARY

Twenty cetacean species were sighted during all ship and aerial surveys. By season, 19 species were

sighted in spring, 14 in summer, 9 in late summer, and 14 in winter. Nine species were sighted in

all four seasons (sperm whale, Cuvier's beaked whale, dwarf/pygmy sperm whale, striped dolphin,

spinner dolphin, pantropical spotted dolphin, Atlantic spotted dolphin, bottlenose dolphin and

clymene dolphin) Bryde's whale, Mesoplodon spp. and Risso's dolphin were sighted during three

seasons. Cetaceans were sighted in all waters searched. With one exception, boftlenose dolphins and

Atlantic spotted dolphins were the only species sighted in the continental shelf study area.

Loggerhead and leatherback sea turtles were sighted during both summer and winter aerial surveys.

(Sea turtles are very difficult to see from a ship.) Leatherbacks were generally found in oceanic

waters during both seasons. Loggerheads were found in shelf waters during both summer and winter

and in oceanic waters primarily during winter only.
Table 2E.1.

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Group-size, density and abundance estimates of cetacean species from aerial surveys

in the continental shelf and slope study areas in the northeastern Gulf of Mexico

during summer and winter 1996-98 (n - number of groups, S - mean group size, D -

animals/i 00 km2, N - abundance estimate, CV - coefficient of variation, LCI and

UCI - lower and upper limits of log-normal 95% confidence interval).

STUDY AR1A

Species n S CV

(S)

N CV

(N)

LCI UCI

CONTINENTAL SHELF

Dwarf/pygmy sperm whale 1 1.0 - 0,081 10 0.84 2 44

flottlenose dolphin 58 7.3 0.19 14.798 1,824 0.25 1,123 2,961

Atlantic spotted dolphin 8 31.8 0.25 8.890 1,096 0.50 426 2,821

T. truncarus/S.frontalis 5 3,3 0.30 0.665 82 0.54 29 231

CONTINENTAL SLOPE

Bryde's whale 2 4.0 0.75 0.035 25 1.06 2 273

Sperm whale 8 1.5 0.18 0.052 37 0.42 17 81

Dwarf/pygmyspermwhale 19 1.8 0.19 0.267 188 0.31 104 343

Cuvier's beaked whale 2 2.0 0.50 0.031 22 0.83 4 116

Mesoplodonspp. 5 2.2 0.22 0.084 59 0.51 23 155

Pygmykillerwhale 3 15.0 0.50 0.309 218 0.75 49 964

False killer whale 1 31.0 - 0.213 150 1.06 27 830

Short-finned pilot whale 1 33.0 - 0.227 160 1.01 31 832

Rough-tootheddolphin 1 34.0 0.234 165 1.02 31 865

Bottlenose dolphin 83 9.9 0.16 5.6 17 3,959 0.22 2,579 6,076

Risso's dolphin 31 8.8 0.23 1.869 1,317 0.32 710 2,444

Atlantic spotted dolphin 15 24.8 0.43 2.555 1,800 0.43 772 4,199

Pantropical spotted dolphin 43 67.4 0.13 19.369 13,649 0.26 8,289 22,475

Stripeddolphin 7 66.7 0.26 3.119 2,198 0.50 860 5,616

Spurner dolphin 7 263.1 0.28 12.302 8,670 0.48 3,462 21,707

Clymene dolphin 5 97,4 0.22 3.253 2,292 0.52 872 6,026

T. truncatus/S.frontalis 5 8.2 0.67 0.282 199 0.81 40 996

Unidentified small whale 1 3.0 - 0.023 16 1.03 3 86

Unidentified odontocete 6 1.3 0.25 0.061 43 0.51 16 113

Unidentified dolphin 1 1.0 - 0.008 5 0.98 1 27
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REFERENCES

Buckland, S.T., DR. Anderson, K.P. Bumham, and J.L. Laake. 1993. Distance sampling: Estimating

abundance of biological populations. Chapman and Hall, London. 446 pp.

Hansen, L.J., K.D. Mullin, T.A. Jefferson and G.P. Scott. 1996. Visual surveys aboard ships and

aircraft. Pages 55-132 in R.W. Davis and G.S. Fargion, eds. Distribution and abundance of

marine mammals in the north-central and western Gulf of Mexico: Final Report. Volume II:

Technical Report. OCS Study MMS 96-0027. U.S. Dept. of the Interior, Minerals Mgmt.

Service, Gulf of Mexico OCS Region, New Orleans, LA. 357pp.

Laake, J.L., S.T. Buckland, D.R. Anderson, and K.P. Burnham. 1993. DISTANCETM users guide,

version 2.0. Colorado Cooperative Fish and Wildlife Unit, Colorado State University, Fort

Collins 72 pp.

Dr. Keith D. Mullin has studied the distribution and abundance of cetaceans in the Gulf of Mexico

since 1985 and is employed by the National Marine Fisheries Service in Pascagoula, Mississippi. He

also teaches marine mammal biology at the Gulf Coast Research Laboratory in Ocean Springs,

Mississippi. He received his Ph.D. in zoology from Mississippi State University.

Mr. Wayne Hoggard has conducted aerial and ship surveys of marine mammals and sea turtles in the

Western Atlantic since 1980. He is employed by the National Marine Fisheries Service in

Pascagoula, Mississippi. He received his B.S. in wildlife biology from the University of Tennessee.

GULFCET II ACOUSTIC SURVEY

Dr. Jeffrey C. Norris

Dr. William E. Evans

Ms. Shannon Rankin

Marine Acoustics Lab

Center for Bioacoustics

Texas A&M University at Galveston

Two acoustic surveys were conducted as part of the GulfCet II program. From 10-29 October 1996

and 4-22 August 1997, we surveyed, from the RTV Gyre, the pelagic waters of the central Gulf south

of the Mississippi River mouth and the northeastern continental shelf and slope waters. These cruises

permitted us to re-sample certain areas of the central Gulf previously examined during GulfCet I

(Norris et al. 1996), while it was the first opportunity acoustically to survey the waters off peninsular

Florida and the shallow shelf areas along the FloridalAlabama border. The area south of the mouth
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of the Mississippi River continues to be an area of intensive oil and gas exploration and production;

therefore, the acoustic surveys permitted further examination of the potential effects these activities

may have on the cetaceans of the area.

A new hydrophone array was used in GulfCet IL It was similar in basic design to the array used in

GulfCet I, having multiple hydrophones variably spaced along a cable. The array is spectrally flat

from 6 Hz to 18 kHz, with approximately 183 dB re. 1V/microPascal sensitivity at 7.2 kHz. Signals

were split such that low frequency sounds were recorded on one system while higher frequency

signals were recorded on a wideband recording system. Dolphin signals were analyzed using Canary

software. Sperm whale signals were analyzed for bearing and range using RainBow Click software

written by Dr. Douglas Gillespie. Bearing to the vocalizing whales are calculated by determiningthe

difference in time of arrival for a signal arriving at two hydrophones within the array. Thispermits

estimation of range to initial contacts and number of animals vocalizing over the duration of the

contact.

There was a total of 5,228 km of acoustic effort, with 2,784 km on cruise Gyre 96G06 and 2,444 km

during cruise Gyre 97G08. The average effort length during Gyre 96G06 was 60 km (n46, 48,

range: 3-199), while for Gyre 97G08 the average length of effort was 31 km (n=78, ci =35, range:

0-138). During Gyre 96G06, effort was fairly uniform throughout the main study areas north of 27°,

with several lines of effort as far south as 25 0 along -88° longitude. Acoustic effort was in waters

as shallow as 5 Om off of the Florida panhandle and Alabama. To the south and east, waters deeper

than 3 ,000m were sampled. In contrast, during Gyre 97G08 there was no effort south of 26°, but with

increased effort to the east along the Florida escarpment.

We had a total of 66 dolphin and 20 sperm whale contacts during the two GulfCet II cruises. There

were twice as many dolphin contacts in cruise Gyre 97G08 during the earlier cruise Gyre 96G06.

There were 11 sperm whale contacts during Gyre 96G06, while there were nine during Gyre 97G08.

We had 13 and 17 unidentified dolphin contacts, respectively, in the two cruises. Sperm whales were

the most commonly encountered identified cetacean during Gyre 96G06, while pantropical spotted

dolphins were the most commonly encountered species during Gyre 97G08.

Cetacean distributions appeared to be affected by the presence during both cruises of paired cyclonic

cold core eddies, to the north, and anticyclonic warm core eddies to the south. While the feature ages

and size were similar in both years, their relative location and orientation were significantly different.

In 1996, the cold core ring was south of the mouth of the Mississippi River, to the northwest of the

warm core ring. In 1997, the cold core ring was northeast of the warm core ring, over the DeSoto

canyon. In no case were cetaceans found in the center of the warm core ring, further emphasizing

the perspective that this is a marine desert. These spatial differences appeared to have produced

different amounts and densities of food, for the cetacean distributions were markedly different for

the two years. In 1996, contacts were more dispersed, and in the case of the sperm whales, the

contacts were significantly longer. In 1997, both sperm whales and pantropical spotted dolphins

distributions were more compact, found either inside or on the periphery of the cold core ring.

During all cruises, sperm whales were located again off the mouth of the Mississippi River, as was

the case during GulfCet I. This area now contains a number of deep water oil platforms, which were
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not present at the beginning of GulfCet I. Sperm whales were found approximately 20 miles further

out to sea than previously, though it is unclear whether this was in response to the increased human

activities in the area.

An area covering over 6,800 kilometers of survey tracklines was monitored acoustically for the

presence of seismic exploration pulses and visually for cetaceans. Seismic exploration signals were

found on 21% of the recordings, for a total of 108.9 hours. For the seven GulfCet I cruises, where

effort concentrated in the central and western Gulf of Mexico, seismic exploration pulses were

present roughly 10% of the time. During GulfCet IJ, where effort concentrated in the central and

eastern Gulf, seismic exploration pulses were present 34.1% of the time. There was no significant

difference in the cetacean sighting frequency for the different acoustic zones (0 dB, 0-12 dB, and>

12 dB above ambient). This finding was consistent for GulfCet I, GulfCet II, and the combined data

set. Hydrographic data was analyzed for the three GulfCet II cruises to understand the potential

interaction of cetaceans within the different hydro graphic regions. There was a significant difference

in the cetacean sighting frequency for the combined hydrographic regions and acoustic levels.

However, within each hydrographic region, there was no significant difference in cetacean sighting

frequency based on acoustic level. It appears that the sighting frequency difference is due to the

hydrographic region, not the acoustic level.

SEABIRD DISTRIBUTION AND HABITAT IN

THE NORTHERN GULF OF MEXICO

Ms. Nancy Hess

Dr. Christine Ribic

University of Wisconsin, Madison

INTRODUCTION

As part of the GulfCet II program, two shipboard seabird surveys occurred from the RJV (}yre during

October 1996 and August 1997. The October and August cruises surveyed an eddy pair in the northcentral Gulf which contained a cyclonic eddy, an anticyclonic Loop Current eddy, and a confluence

region between the eddies, and the northeastern region over the continental shelf and slope in the

Minerals Management Service's Eastern Planning Area (EPA).

METHODS

Seabird observations occurred during daylight hours by two observers using hand-held 8X or lox

binoculars on the flying bridge of the R/V Gyre. The seabird surveys consisted of continuous strip

transects, using the method of Tasker et al. (1984). The survey area was measured off one side of

the ship, sweeping from the bow to 900 from the direction of the ship.
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Total species numbers were tallied to assess overall abuxidance. Species abundance in the 300 m strip

transect by bydrographic environment was tallied to initially assess species distributions, as well as

species diversity, richness and evenness for both the October and August cruises. To conduct species

specific habitat analyses, we split the continuous strip transects into approximately equal length strip

segments with a target lengths of 15 kilometers. For the October 1996 survey a 300 m transect band

width was used. For the August 1997 survey, a 600 m transect band width was used. For each

transect, the presence or absence of seabirds was tallied for the most abundant species seen during

the cruise. Analyses were conducted only for species seen in at least 10% of the transects.

To decrease the amount of correlation between the predictor variables, and to testcompeting hypotheses, we developed five models ofseabird presence incorporating bathymetry, sea surface physical

properties (salinity and temperature), sea surface height, predicted mean zooplanktonbiomass (from

acoustic backscatter), and surface chlorophyll concentrations. We used generalizedadditive models,

a nonparametric smoothing technique which allows for nonmonotonic nonlinear relationships that

are difficult to model with standard regression techniques. We compared the fits of the different

models based on the proportion of variance explained and Akaike Information Criterion.

RESULTS FOR OCTOBER 1996 SURVEY

Two-hundred and seventy-eight (278) seabirds were counted and 14 species were seen during the

October cruise. Together terns, gulls,jaegers, and shearwaters comprised over 90% of the total birds

enumerated. Frigatebirds, tropicbirds, boobies and storm-petrels were also seen. Many terns were

not identified to species (55 out of 128 terns). Over a quarter of the total terns seen were royal tems

(36 birds). Black terns (nine birds) and common terns (eight birds) were the next most abundant

terns; sooty terns, bridled terns, bridledlsooty terns, and commonlarctic terns accounted for the

remaining twenty terns counted. The majority of gulls seen were laughing gulls (55 out of 65 gulls

seen); seven herring gulls were seen, and three gulls were not identified to species level. Out of the

38 jaegers seen, 25 were identified as pomarine j aegers; the rest were not identified. Audubon's

shearwaters comprised almost half of the shearwaters seen (11 out of 24 birds); seven Cory's

shearwaters were spotted and the remaining six shearwaters were not identified to the species level.

All 12 frigatebirds were magnificent frigatebirds. Four tropicbirds were seen, two were red-billed

tropicbirds. The other two were not identified to species. Four masked boobies were seen. Three

storm-petrels were seen, two of which were identified as band-rumped storm-petrels, and one was

not identified to the species level.

Out of the birds seen within the 300 m continuous strip transect, some species were seen in many

of the marine environments surveyed (see Evans et al., these proceedings) and some species were

seen only in one or two environments. Laughing gulls were present in every region except for the

confluence; however, laughing gulls were present in the greatest numbers on the continental shelf.

Audubon's shearwaters and pomarine jaegers were seen in five out of the seven environments.

Audubon's shearwaters were not seen in either the Loop Current eddy or other regions in depth

greater than 200 m but not contained within the eddy pair (other margin) and pomarinejaegers were

not seen in the Loop Current eddy or the continental shelf. Royal terns were seen in the mouth of the

Mississippi River and other margin regions. Cory's shearwater and masked boobies were seen only
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in the cyclone and in other margin regions. Herring gulls and magnificent frigatebirds were seen in

other margin and continental shelf; however, a herring gull was also present in the cyclone. Bandrurnped storm-petrels and the red-billed tropicbird were seen inside the cyclone. The sooty tern and

common tern were seen in other margin

Species richness (i.e. the number of seabird species seen) in the 300 m continuous strip transects

varied with marine environment. The most species (nine) were seen in other margin (regions with

bottom depth greater than 200 m not directly associated with the Loop Current eddy system); this

area outside of the Loop Current system contained almost one-third the survey effort. The cyclone

contained eight species, the next highest number in any environment. The mouth of theMississippi

River and continental shelf contained four species. The edge of the cyclone, the confluence, and

Loop Current eddy contained three or less species. We note that these environments were covered

with less effort than the others.

RESULTS FOR AUGUST 1997 SURVEY

During the August 1997 cruise, over 2,100 seabirds were counted, representing twenty-three species.

Two-thirds of the seabirds seen were terns. Storm-petrels were the next most abundant group (323

birds). Shearwaters (194 birds), frigatebirds (178 birds), gulls (40 birds),jaegers (18 birds), boobies

(four birds) and tropicbirds (two birds) were also seen. The majority of terns seen were black terns,

which accounted for half of all seabirds seen. Sooty terns (111 birds) were the second most abundant

tern species. Bridled terns (70 birds) and either bridled or sooty terns (73 birds) were the next most

represented tern. Twenty-four sandwich terns were seen, and nineteen royal terns were seen. Two

arctic terns, four common terns, three common or arctic terns, and one least tern were also

encountered. One hundred and three terns were not identified to species. The majority of stormpetrels seen were band-rumped storm-petrels (250 out of 323 birds). Ten Wilson's storm-petrels, and

one Leach's storm-petrel were counted. Sixty-two storm-petrels were not identified to species. Five

different species of shearwaters were encountered during the August cruise. The majority of

shearwaters seen were Audubon's shearwater (154 out of 194 birds). Ten Cory' s shearwaters, five

Manx shearwaters, three greater shearwaters, and one sooty shearwater were seen. Twenty-one

shearwaters were not identified to species. One hundred and seventy-eight frigatebirds were counted.

Most likely, these were all magnificent frigatebirds; no other frigatebird is known to be present in

the Gulf. All of the gulls identified to species were laughing gulls (38 birds) and two gulls were

unidentified. Three-fourths ofthej aegers seen were pomarinej aegers (14 out of 18 birds). Two longtailed jaegers, one parasitic jaeger and one unidentified jaeger were enumerated. All four boobies

seen were masked boobies. The two tropicbirds seen were red-billed tropicbirds.

The distribution of species seen within the 300 m continuous strip transect across the different

marine environments was not uniform; many species were only seen in certain locations. Frigatebirds

were only seen on the continental shelf, as was the long-tailed jaeger. Royal terns, sandwich terns,

and black terns were seen predominantly on the continental shelf. The two masked boobies seen

within the 300 m strip transect were seen in the cyclone, and four out of the five Manx shearwaters

were also seen in the cyclone. I3and-rumped storm-petrels were seen in all of the environments

except for the mouth of the Mississippi River. A large number of band-rumped storm-petrels were
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seen in the pelagic regions not directly influenced by the eddy pair in addition to the confluence and

cyclone. Laughing gulls were found mainly on the continental shelf and confluence but also were

present in the Loop Current eddy, cyclone and the edge of the cyclone. Black terns, while

predominantly found on the continental shelf, were also found in the confluence, mouth of the

Mississippi River, cyclone, and Loop Current eddy. Audubon's shearwaters were found in the

confluence, cyclone, Loop Current eddy and the edge of the cyclone. Bridled ten's were seen

predominantly in the cyclone, confluence and Loop Current eddy. Sooty terns were also seen in the

cyclone, confluence and Loop Current eddy, but were seen in larger numbers in other margin.

The pelagic regions outside of the eddy pair and cyclone contained the greatest number of species.

Fewer species were found on the continental shelf, confluence and Loop Current eddy. Only four or

five species were encountered in the mouth of the Mississippi River and edge of cyclone; however,

these environments were covered with the least survey effort. Diversity was the greatest in the

cyclone followed by the Loop Current eddy and confluence. The continental shelfhad the lowest

species diversity, resulting from the large numbers of black terns.

The results of both cruises indicate that the cyclone had the greatest species diversity out of all

environments. Additionally, the confluence and Loop Current eddy during August 1997had a greater

species diversity than the continental shelf. On the scale of analysis for this report (15 kilometers),

we found species-specific habitat relationships with the different marine environments. Audubon's

shearwaters during the August survey were more likely to be encountered inside the cyclone. Black

terns were encountered more frequently in the mouth of the Mississippi River during the August

1997 survey.

RESULTS FOR SEABIRD-ENVIRONMENT MODELS

On the scale used in this analysis, we found that a generalized additive model using indicators of

plankton standing stock (measured by surface chlorophyll and predicted mean zooplankton biomass

(from acoustic backscatter) integrated from 10-102 m depth) best predicted seabird presence for

laughing gull, pomarinejaeger, Audubon's shearwater and band-rumped storm-petrel.

Laughing gull presence during October was predicted in transects of increased predicted mean

zooplankton biomass (from acoustic backscatter) integrated from 10-102 m depths and increased

concentrations of chlorophyll. Ribic etai. (1997) found laughing gulls to be found in areas of low

salinity and steep thermoclines. These findings are consistent; during the October 1996 survey, there

was an inverse relationship with salinity and chlorophyll concentration. Pomarmne jaegers during

October were predicted to be encountered in transects with low surface chlorophyll and higher

predicted mean zooplankton biomass (from acoustic backscatter) integrated from 10-102 m depth.

For the October survey, chlorophyll values were lower in more saline water. The relationship of the

j aegers with chlorophyll may signify that they are present in more saline water (i.e. farther offshore).

Ribic et al. (1997) found similar results of pomarine jaeger presence in water with lower primary

productivity (as measured by the integrated values of chlorophyll in the top 100 m of the water

column). We found pomarmne jaegers in areas of lower surface chlorophyll, but in higher levels of

predicted mean zooplankton biomass (from acoustic backscatter) integrated from 10-102 m depth.
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Audubon's shearwater and band-rwnped storm-petrel presence during August were best predicted

by the model including surface chlorophyll and predicted mean zooplankton biomass (from acoustic

backseatter) integrated from 10-102 m depth. Both species were predicted to be present at generally

lower surface chlorophyll concentrations. This cutoff may signify that neither species is present in

fresher water. Transects with higher chlorophyll concentrations were also in less saline water.

Black and sooty tern species' presence in transects was best predicted by the surface properties

model of sea surface salinity arid temperature. This was expected for black ten's, which have been

noted to follow the fresh water plume of the Mississippi River and coastal waters (Ribic et al. 1997;

Davis and Fargion 1996). Although sooty tern presence in transects was best explained by the same

surface physical properties model, the relationship was not the same as with black ten's. Sooty terns

were predicted to be present in salinity of about 32 psu which is more saline water than where the

black terns were found. However, the percent of total variance explained by the model was low;

there are probably other factors not considered that contribute to the distribution of sooty ten's in the

Gulf of Mexico.

CONCLUSION

The two cruises provided more information regarding the seasonal patterns of seabirds in the Gulf

of Mexico. The role of hydrographic environments and species diversity was examined, and we

found an increase in species diversity in the cyclone and lower species diversity on the continental

shelf. On a species-specific level, black ten's and Audubon's shearwaters tended to be present in

specific environments. However, each of these species preferred a different region; black ten's

favored the mouth of the Mississippi River, and Audubon's shearwaters preferred the cyclone.

Species' presence in a transect was analyzed with models incorporating bottom depth, sea surface

properties, and indicators of plankton standing stock in the water column using generalized additive

models. Our results suggest laughing gull, pomarinej aeger, Audubon's shearwater, and band-rumped

storm-petrel presence was best predicted by indicators of plankton standing stock (using sea surface

chlorophyll concentrations and predicted mean zooplankton biomass (from acoustic backscatter)

integrated from 10-102 m depth). In contrast, the two tern species (black tern and sooty tern)

presence was best predicted by sea surface temperature and salinity.

ACKNOWLEDGMENTS

We would like to thank Dr. Ned Brinkley, Melissa Davis, Brad Dawe, and Dr. Dwight Peake for

their volunteer efforts in bird observations. This research is supported by the USGS Biological

Resources Division and by the US Minerals Management Service under a research work order to the

Wisconsin Cooperative Wildlife Unit, UW-Madison.

REFERENCES

Davis, R.W., and G.S. Fargion, eds. 1996. Distribution and abundance of cetaceans in the northcentral and western Gulf of Mexico: Final Report. Volume II: Technical Report. OCS Study

MMS 96-0027. Prepared by the Texas Institute of Oceanography and the National Marine
309

Fisheries Service. U.S. Dept. of the Interior, Minerals Mgmt. Service, Gulf of Mexico OCS

Region, New Orleans, LA. 357 pp.

Ribic, C.A., R. Davis, N. Hess, and D. Peake. 1997. Distribution of seabirds in the northern Gulf of

Mexico in relation to mesoscale features: initial observations. ICES J. Mar. Sci. 54:545-551.

Tasker, M.L., P.H. Jones, T. Dixon, and B.F. Blake. 1984. Counting seabirds at sea: A review of

methods employed and a suggestion for a standardized approach. Auk 101:567-577.

Ms. Nancy Hess is a Research Assistant in the Department of Wildlife Ecology at the University of

Wisconsin, Madison where she is currently pursuing masters degrees in wildlife ecology and statistics. She received her B.S. in biology and B.A. in history from the University of Richmond, Virginia.

Dr. Christine Ribic is an Associate Professor in the Department ofWildlife Ecology at the University

of Wisconsin, Madison. She is also Assistant Unit Leader of the USGS BRD Wisconsin Cooperative

Wildlife Research Unit. Her areas of research interest are the importance of scale to seabird-habitat

relationships and the influence of physical oceanographic features on seabird habitat selection. Dr.

Ribic received her B.S. in wildlife biology from Colorado State University and her M.S. in ecology,

M.S. in statistics, and Ph.D. in ecology from University of Minnesota.
Northeastern Gulf of Mexico Coastal

and Marine Ecosystem Program:

Ecosystem Monitoring, Mississippi!

Alabama Shelf; Introduction and

Overview

Mississippi-Alabama Marine Ecosystems

Study Geological Characterization:

High-Resolution Geological and

Geophysical Study of Outer Shelf

Carbonate Mounds and Their Environs

Northeastern Gulf of Mexico Coastal

and Marine Ecosystem Program:

Ecosystem MonitoringPhysical

Oceanography and Hydrography in the

MississippilAlabama Pinnacle Trend

Area during May 1997 through April

1998 and during September 1998

SESSION 2F

NORTHEASTERN GULF OF MEXICO ECOSYSTEM PROGRAM:

MISSISSIPPI-ALABAMA MARINE ECOSYSTEM MONITORING PROGRAM

Co-Chairs: Dr. Robert Rogers and Dr. Gary Brewer

Date: December 9, 1998

Presentation Author!Affiliation

Dr. David A. Gettleson

Continental Shelf Associates, Inc.

Jupiter, Florida

311

Dr. William W. Sager

Department of Oceanography

Texas A&M University

Dr. William W. Schroeder

Marine Science Program

University of Alabama

Dr. Ian R. MacDonald

Geochemical & Environmental Research Group

Texas A&M University

Dr. Ian D. Walsh

Department of Oceanography

Oregon State University

Mr. F.J. Kelly

Dr. Norman L. Guinasso, Jr.

Mr. Linwood L. Lee, III

Geochemical and Environmental Research Group

College of Geo sciences

Texas A&M University
312

Presentation Author/Affiliation

Northeastern Gulf of Mexico Coastal

and Marine Ecosystem Program:

Ecosystem Monitoring, Mississippi/

Alabama Shelf; Hard Bottom

Communities

Epibiont Recruitment

Mr. David B. Snyder

Mr. Keith D. Spring

Mr. Bruce D. Graham

Mr. Steven T. Viada

Continental Shelf Associates, Inc.

Jupiter, Florida

Mr. Dane D. Hardin

Applied Marine Sciences

Santa Cruz, California

Dr. Paul Montagna

Ms. Tara Holmberg

University of Texas Marine Science Institute

Port Aransas, Texas
NORTHEASTERN GULF OF MEXICO COASTAL AND MARINE ECOSYSTEM

PROGRAM: ECOSYSTEM MONITORING, MISSISSIPPI/ALABAMA SHELF;

INTRODUCTION AND OVERVIEW

Dr. David A. Gettleson

Continental Shelf Associates, Inc.

Jupiter, Florida

INTRODUCTION

Continental Shelf Associates, Inc. (CSA) was awarded a contract by the U.S. Geological Survey,

Biological Resources Division to conduct an ecological study of aii area offshore Mississippi!

Alabama. The project team consists of CSA, the Geochemical & Environmental Research Group of

Texas A&M University, University of Texas, Applied Marine Sciences, Inc., and independent

consultants.

GEOGRAPHIC AREA OF STUDY

The geographic area of study is the Mississippi-Alabama pinnacle trend area in approximately 50

to 150 m water depths (Figure 2F.1). Several studies have been conducted in the area, which was

first described by Ludwick and Walton (1957). There have been four Minerals Management

Service-funded studies (Woodward-Clyde Consultants 1979; Brooks 1991; Continental Shelf

Associates, Inc. 1992; Shinn et al. 1993) and an oil and gas lease block clearance survey (Continental

Shelf Associates, Inc. 1985) conducted in the area.

STUDY OBJECTIVE

The objective of this study is to describe and monitor biological communities and environmental

conditions at hard-bottom features located within the geographic area of study. A number of oil and

gas lease blocks are encompassed by the study areawith at least one oil and gas production platform

present. Information gained from this study will be used to review existing lease stipulations to

determine their adequacy in protecting the biological communities present on the hard-bottom

features. This study also meets several objectives of the National ResearchCouncil (1992) regarding

the assessment of environmental impacts from oil and gas operations. These objectives include (1)

identifying representative species; (2) describing seasonal patterns; (3) acquiring basic ecological

information for key or representative species; and (4) obtaining information on factors that determine

sensitivity of biota to outer continental shelf activities and their recovery potential.

STUDY COMPONENTS

313

The four-year study is divided into four phases of one year duration each with annual reports planned

at the end of each phase. The phases are as follows:
0 WESTERN Leg end Megailte I' -SiteCENTRAL0p.p.p.p. II!PlVlAEASTE

LOCATiON 

Gulf of Mexic

AL1

A

SH

Figure 2F. 1. Locations of final monitoring sites.
Phase 1 - Reconnaissance, Baseline, and Monitoring;

Phase 2 - Monitoring;

Phase 3 - Monitoring; and

Phase 4 - Data Interpretation and Information Synthesis.

Nine of the 11 cruises planned for the study have been completed. These encompassed

reconnaissance (one cruise), baseline (one cruise), monitoring (three cruises), and mooring servicing

(four cruises). During the reconnaissance portion of Phase 1, five "megasites" (Figure 2F.1)

(approximately 25 to 35 km2 areas) were selected for detailed study. These sites were selected as

being representative of the hard-bottom features previously identified in the area (Brooks 1991;

Continental Shelf Associates, Inc. 1992). The megasites were surveyed in November 1996 using

swath bathymetry, high resolution side-scan sonar (11 and 72 kHz), and a subbottom profiler (2 to

8 kllz). Nine areas of approximately 0.2 to 1.5 km2 size were selected during the cruise and surveyed

in more detail. Previously collected video and still photographic data from these nine sites were

reviewed and additional visual data collected using a remotely operated vehicle to aid in the selection

of nine study sites. The study sites were selected to provide representative hard-bottom features of

high, medium, and low relief in the eastern, central, and western portions of the study area (Figure

2F.1).

The focus of the baseline and monitoring portions of the study is to understand the geological and

oceanographic processes as factors in controlling/influencing the hard-bottom communities at the

nine study sites. Data were gathered during the reconnaissance survey on substrate characteristics;

hard-bottom orientation, size, and morphology; and depth of surrounding soft sediments. Three of

four baseline and monitoring cruises have been completed (April 1997, October 1997, and August

1998). The remaining monitoring cruise will be conducted May 1999. Data on microtopography are

being obtained from the collection and analysis of rock samples and video and photographic data

during these cruises. Grab samples collected during the monitoring cruises are being analyzed for

grain size (four cruises) and concentrations of hydrocarbons and metals (first cruise only). Six

instrument arrays composed of current meters; sediment traps; and temperature, salinity, dissolved

oxygen, and turbidity (optical backscattering) sensors were deployed during the first cruise in the

vicinity of the hard-bottom features. The arrays are being recovered and redeployed at three-month

intervals and recovered on the fourth monitoring cruise. Sediment trap contents are being analyzed

for grain size, total inorganic and organic carbon, and metals. During each of the four cruises, water

column profiles are being made for conductivity, temperature, dissolved oxygen, transmissivity, and

optical backscatter, and samples are being collected for analysis of particle sizes, dissolved oxygen,

and salinity.

Biological data include quantitative still photographs from fixed quadrats and random stations and

quantitative video from random transects during the four cruises. Voucher specimens are also being

collected to aid in taxonomic identifications of biota observed in the visual data. Fish assemblages

associated with the study sites are being described from the available visual data collected during

the monitoring surveys. There are two additional biological "companion" studies. The first involves

a more in-depth analysis of the biological, geological, and physical data on a micro-habitat basis. The

second involves the deployment of settling plates on fixed arrays to study epibiota recruitment,

315
316

growth, and community development. Settling plate arrays include enclosed and non-enclosed plates

plus controls to study predationldisturbance effects. Plates were placed near bottom and above any

identified nepheloid layer. Eight arrays were placed at one site and one array was to be recovered

each quarter. Due to hardware failure, the arrays sank to the bottom. They were arid will be recovered

by a remotely operated vehicle (one array in October 1998; three in August 1998; and four in May

1999). One array also was placed at each of three additional sites to be recovered after one year. The

arrays at two of the three sites were recovered in August 1998. Turbidity prevented the recovery of

the third array, which will be recovered in May 1999. An additional array was deployed at each of

the three sites plus the multi-array site in January 1998 and will be recovered in May 1999.

The data interpretation and synthesis efforts will involve understanding the relationship of the

measured geological and physical factors to the hard-bottom communities through statistical

analyses. A series of questions determined by the study objective with clearly stated null hypotheses

also will be identified and statistically tested.

REFERENCES

Brooks, J.M. (ed.). 1991. Mississippi-Alabama Continental Shelf Ecosystem Study Data Summary

and Synthesis. OCS Study MMS 91-0063. U.S. Department of the Interior, Minerals

Management Service, Gulf of Mexico OCS Regional Office, New Orleans, La.

Continental Shelf Associates, Inc. 1985. Live-bottom survey of drillsite locations in Destin Dome

Area Block 617. Report to Chevron U.S.A., Inc. 40 pp. + app.

Continental Shelf Associates, Inc. 1992. Mississippi-Alabama Shelf Pinnacle Trend Habitat

Mapping Study. OCS Study MMS 92-0026. U.S. Department of the Interior, Minerals

Management Service, Gulf of Mexico OCS Regional Office, New Orleans, La. 75 pp. + app.

Ludwick, J.C. and W.R. Walton. 1957. Shelf-edge, calcareous prominences in the northeastern Gulf

of Mexico. Amer. Assoc. Petrol. Geol. Bull. 41(9):2,054-2,101.

National Research Council. 1992. Assessment of the U.S. Outer Continental Shelf Environmental

Studies Program. Volume H: Ecology. National Academy Press, Washington, DC. 152 pp.

Shinn, E.A., B.H. Lidz, and C.D. Reich. 1993. Habitat impacts of offshore drilling: Eastern Gulf of

Mexico. OCS Study MMS 93-002 1. U.S. Department of the Interior, Minerals Management

Service, New Orleans, La. 73 pp.

Woodward-Clyde Consultants. 1979. Eastern Gulf of Mexico marine habitat mapping study. Report

to U.S. Department of the Interior, Bureau of Land Management, OCS Office, New Orleans, La.

Contract No. AA551-CT8-22.
317

Dr. David A. Gettleson is President and Scientific Director of Continental Shelf Associates, Inc.

(CSA), located in Jupiter, Florida. He has 19 years ofscientific management experience with maj or

research programs for federal, state, and industrial clients. He has been involved in the preparation

of numerous environmental assessment documents covering a wide range of human activities in the

marine environment, including oil and gas operations, dredging and dredged material disposal, beach

restoration, artificial reef siting, power plant effluents, sewage outfalls, and waste incineration. Dr.

Gettleson received a B.A. degree in Biology from Rollins College in 1971 and earned his Ph.D.

degree in biological oceanography from Texas A&M University in 1976.

MISSISSIPPI-ALABAMA MARINE ECOSYSTEMS STUDY GEOLOGICAL

CHARACTERIZATION: HIGH-RESOLUTION GEOLOGICAL AND GEOPHYSICAL

STUDY OF OUTER SHELF CARBONATE MOUNDS AND THEIR ENVIRONS

Dr. William W. Sager

Department of Oceanography

Texas A&M University

Dr. William W. Schroeder

Marine Science Program

University of Alabama

Dr. Ian R. MacDonald

Geochemical & Environmental Research Group

Texas A&M University

Dr. Ian D. Walsh

Department of Oceanography

Oregon State University

INTRODUCTION

Sedimentation on the outer continental shelves in the northern Gulf of Mexico is an interplay

between sediment supply and sea level fluctuations. Most sediments aredeposited as deltaic wedges

during sea level lowstands and are separated by condensed layers representing transgressive periods

(e.g., Coleman et al. 1991). Such shelf-edge deltaic wedges are observed on the Mississippi-Alabama

outer shelf in bathymetric contours and reflection seismic data (Kindinger 1988; 1989; McBride and

Byrnes 1995). Sedimentation is low ill this region today, and indeed much of the outer shelf is

covered by relict transgressional sands (Ludwick 1964; Doyle and Sparks 1980). Shelf-edge delta

sediments indicate sedimentation was higher during the last ice age and previous glacial intervals

(e.g., Sydow and Roberts 1995). Siliciclastic delta sediments are not the oniy contributor to

deposition on the outer shelf. Early studies of the Mississippi-Alabama outer continental shelf found
31S

calcareous topographic features (named "pinnacles") near the shelf edge that appeared to have

formed near sea level. Although these pinnacles (henceforth we use the more generic term

"mounds") probably formed during or shortly after the last ice age when sea level was lower, they

are now senescent because they are too deep for active growth (Ludwick and Walton 1957). These

mounds are apparently the source of calcareous sediments found in their vicinity (Ludwick 1964).

Much of our current geological knowledge of the Mississippi-Alabama carbonate mounds and their

surroundings come from two prior MMS-thnded studies: Mississippi-Alabama Marine Ecosystems

Study (MAMES; Brooks et al. 1991) and Mississippi-Alabama Shelf Pinnacle Trend Habitat

Mapping Study (MASPTHMS; Continental Shelf Associates 1992) both of which mapped the

occurrence of carbonate mounds and the distribution of surficial sediments. Thousands of carbonate

mounds ranging from less than a few meters in diameter to nearly a kilometer were found arrayed

mostly in two isobath-parallel bands (Sager etal. 1992). Isobath-parallel ridges were also mapped

in the shallower of these two depth zones. Both features are thought related to sea level stillstands

during the last deglaciation. Surficial sediments are largely related to three late Pleistocene deltas,

the Lagniappe Delta (Kindinger 1988; 1989) in the western part of the present study area (Figure

2F.2) and the "eastern" and "western" deltas in the original MAMES study area (Sager et al.

submitted). These delta sediments were deposited during sea level lowstands or in the case of the

"eastern delta," during the early part of the last deglaciation (Sager et al. submitted). Atop these

sediments is a thin, variable layer, consisting mostly of sand, that is thought to have been deposited

by reworking of shelf sediments near sea level as it rose across the shelf during the last deglacial

transgression (Sager et al. submitted).

The current project picks up where MAMES and MASPTHMS left off. Those projects were

reconnaissance efforts to broadly characterize the Mississippi-Alabama outer continental shelf,

whereas this study seeks more detail. The current project has two main goals: (1) detailed geologic

and geophysical characterization of mound morphology, roughness, and locations and (2) an

examination of sedimentation in the vicinity of the mounds. The first set of goals was addressed by

collection of side-scan sonar data, seismic reflection profiles, grab samples, and ROV photos of the

seafloor. Sedimentation is being examined in conjunction with the physical oceanography and

hydrography portion of the program by the deployment of sediment traps and optical backscatter

instruments.

METHODS

During November 1996, five sites (called "megasites" to distinguish them from smaller monitoring

sites), typically several kilometers on a side and totaling 144.5 km2 in area, were surveyedusing the

TAMU2 digital side-scan sonar system to make acoustic images of the seafloor and bathymetric

soundings (Figure 2F.2). In addition, a 2-12 kHz X-Star chirp sonar was used to acquire subbottom

profiles. These acoustic data were collected along tracks spaced 175 m apart with image swaths that

produced 100% overlap (so all spots on the seafloor were imaged twice from adjacent tracks).

Positions were established to an accuracy of less than about 10 musing differential UPS and a shortbaseline trackpoint system to determine the sonar towfish location. Sonar swaths were mosaicked

into whole-megasite images (Figure 2F.3), with a resolution of about 1 m, for subsequent geologic
319

Figure 2F.2. Location map showing the study areas on the Mississippi-Alabama outer continental

shelf. Boxes show prior studies in the area. Small, dark boxes show the five

megasites surveyed with a side-scan sonar and subbottom profiler for this project.

Hachured areas show deltas described in Kindinger (1988) and Sager et al.

(submitted).
Figure 2F.3. TA MU2 side-scan sonar mosaic of Megasite 1. Vertical (north-south) image strips 175 m in width 

combined to make a sonar mosaic several kilometers on a side. Dark areas (sonar-bright) show pla

seafloor where sound is strongly reflected back to the sonar whereas light areas (sonar-dim) show sound is not strongly reflected or there is an acoustic shadow. In general, rough seafloor and coarssediments yield sonar-bright returns (Johnson and Helferty 1990). The boxes labeled Site 1 to Site locations of monitoring sites within the megasite. Coordinates are UTM x and y (in meters).
321

interpretation. Sonar images such as these show variations in acoustic returns, which are caused by

topography and seafloor roughness (Johnson and Helferty 1990).

TA MU2 bathymetry data were processed into depth grids with a 15-rn spacing for the megasites and

a 1-rn spacing for small areas around the monitoring sites. These data have been plotted at a 1-rn

contour interval for interpretation (Figure 2F.4).

Subbottom profiler data are being studied to examine the thickness and character of shallow

sediments in the study areas. The profiles have been analyzed using standard seismic stratigraphic

techniques (e.g., Mitchuni et al. 1977), which involves recognition and correlation of acoustic

reflectors by their characteristics and mapping and interpretation of seismic facies.

During Cruise 1C in April 1997, 94 grab samples and 13 box cores were collected to provide surficial sediment samples for grain-size measurements. On each of two subsequent cruises, 45 grab

samples were collected by re-occupying previous grab stations from the first cruise. These repeat

samples reflect sediment variability. Standard grain-size analyses are performed on these samples.

Digital underwater photographs and videos were taken at 100 random stations at each of the nine

monitoring sites on three monitoring cruises. Although these photographs were taken to characterize

benthic organisms, they are also useftil for examining geologic substrate character. We have

examined these photographs for various geologic characteristics (Table 2F. 1). The photographs show

an area less than one meter on a side, so most of the characteristics are relevant to small-scale

features (i.e., centimeter size); however, by using video camera records during the approach and

departure from each station, other larger scale characteristics can be determined. By plotting the

various characteristic descriptors at station locations and comparing, it is possible to examine

relationships among characteristics.

Three sediment traps and one optical backscatter (OBS) instrument were deployed on each of six

current moorings. The sediment traps were used to measure sedimentation rates and resuspension

flux and the OBS devices were used to monitor the occurrence of nepheloid layers. The sediment

traps were mounted on the moorings at 2, 7, and 15 m above the seafloor, the idea being that the

lower sediment traps yield resuspended sediments near the seafloor. The OBS was mounted at 2.3

m. Four of the moorings were deployed at one location for the entire study, at monitoring sites 1, 4,

5, and 9. The other two moorings were periodically moved; they were deployed at Site 1 for the first

year and Site 5 for the second year. Vertical profiles of conductivity, temperature, and optical backscatter were taken at each station on each mooring service cruise (approximately every 6 months).

RESULTS AND DISCUSSION

Geophysical Data

Three sites were similar in their bathymetric and side-scan image characteristics and two were

dissimilar. Megasites 1, 3, and 5 all show mostly subcircular mounds of varying diameters typically

arrayed in tight to loose clusters (Figure 2F.3). The mounds have relief ranging from less than a
Figure 2F.4. TAMU2 sonar bathymetry map of Megasite 1. Contours at 1-rn intervals with every multiple of 5-

heavy line. Coordinates are UTM x and y (in meters).
Table 2F.1. Geologic descriptors of the seafloor at ROV photo stations.

323

meter to greater than 10 m and have diameters ranging from several to hundreds of meters. Megasite

4 was found to be devoid of large mounds and mound clusters, whereas Megasite 2 contains many

tall, irregular mounds often occurring atop broad, low, carbonate hard grounds. Megasite 3 also

contained two somewhat similar low hard grounds. The mosaics show that most mounds are

subcircular in shape (i.e., having aspect ratios near 1). Often larger mounds consist of smaller,

subcircular elements, as if the bigger mounds formed by the coalescing of many smaller mounds. In

several places, notably megasites 3 and 5, a few large linear mounds were observed and typically

these are aligned along the isobath contours.

Flat seafloor in the survey areas typically shows up as light gray, which indicates weakly-reflective

fine grained sediments. Grab samples indicate these are sands containing few larger grains. Mounds

within the megasite mosaics are typically "sonar bright" (i.e., they give high-amplitude reflections)

owing to their roughness. In addition, they are also typically surrounded by sonar-bright sediments.

Grab samples indicate this high acoustic return from the sediments around the mounds is due to

coarser texture caused by greater concentrations of carbonate and shell fragments. In megasites 1,

3, and 5, the sonar-bright sediments are preferentially located on the southwest sides of the larger

mounds and mound clusters, suggesting currents have preferentially concentrated coarse sediments

in these locations. In addition, many medium-sized mounds have long, sonar-bright "tails" that trend

to the southwest. These tails are correlated with shallow erosional channels on subbottom profiles,

implying the tails are an indicator of current direction. Interestingly, the trends of these tails are

relatively constant within each megasite, although they vary slightly from one megasite to another.

The similarity in feature orientations suggests that regional currents caused the sonar-bright sediment

patches on the southwest sides of the larger mounds. Subbottom profiles often show some indication

of erosion in these locations as well, suggesting a relationship of sonar backscatter to erosion.

Perhaps the bright patches result from winnowing of finer sediments and the resulting development

of coarse lag deposits. Interestingly, the two deepest megasites, 2 and 4, show no preferred

orientation of the sonar-bright patches around mounds. Indeed, at Megasite 2, these patches are

General Morphology RLM Relief Roughness Sediment Sediment

(large scale) type (scale m) (scale cm) texture Cover

No rock visible NA NA Flat NA Fine NA

Depression Coarse

Mound Shell hash

Rubble

Rock outcrop Boulder Base Low Low Fine None

Ridge Face Medium Medium Coarse Partial

RLM Top High High Shell Hash Complete

Flat Rubble

Overhang

NAnot applicable
324

symmetric around most mounds. It is not yet clear whether the bottom currents that caused these

features are normal currents or whether the features were caused by one or more transient events,

such as storms.

Bathymetry data show the mounds in megasites 1, 3, and 5 occur in water depths of-90 to 72 m.

Typically the mounds are subcircular in shape, but occasionally they are linear, following isobath

orientation. In Megasite 1, the mound clusters are not obviously aligned, but in Megasite 5, they are

aligned nearly parallel to isobaths along the shelf edge. In Megasite 3, a linear, isobath parallel

cluster is observed in addition to looser clusters not obviously related to depth. Megasite 2 contours

show large irregular mounds, some low and broad and others tall and steep-sided. These mounds are

also arrayed in linear clusters and near the shelf edge, but the lineations cross isobaths and so there

is no clear relation to depth. Depth contours are often more widely spaced on the north sides of the

mound clusters in megasites 1, 2, 3, and 5, indicating the damming of southward moving sediments

by these topographic features.

Subbottom profiles in the study areas have proven useful for interpreting sonar features, especially

where mound flanks are buried by sediment. Typically the profiles show a relatively uniform 1 to

2 m surface transparent layer overlying a somewhat thicker and more variable layer. In some, but not

all profiles, the erosional unconformity presumably formed during the last glacial lowstand can be

discerned. Because this unconformity is not widely imaged in this survey, the thickness of postglacial sediments cannot be mapped over large areas with the existing data. Nevertheless, the nearly

uniform transparent layer argues that recent sedimentation has been relatively constant.

ROV Seafloor Photos

ROV photos show highly variable substrate characteristics on and around the carbonate mounds.

Away from the mounds, the seafloor is typically flat and nearly completely covered with fine-grained

sediments. However, on the mounds and at their periphery, outcrops are common, roughness ranges

from low to high, sediment cover is incomplete, the texture is typically coarse, and topographic

gradients can be high (Figure 2F.5).

Sediment Grain Size

Grab sample sediments are typically clayey sands with a bimodal grain size distribution. This

distribution is typically strongly peaked in the sand size range, reflecting the fact that the sediments

are part of the MAFLA sand sheet (Ludwick 1964; Doyle and Sparks 1980), a transgressive relict

sand. The mean grain size for all samples is 2.8 p, in the fine sand range of the Wentworth scale.

However, many samples have a significant clay fraction. This is clear from the sample distribution

on a sand-silt-clay ternary diagram (Figure 2F.6) in which most samples group near the sand apex,

but the distribution is nearly linear and trends toward the clay apex. It appears the sediments are a

well-sorted sand into which a fraction of clay has been introduced. A likely source of this clay is the

sediment plume of the Mississippi River (Shepard 1956).
I :1 A A A LAL4 A Sedimect ccMw $dirncct Texture A CCn4t] Partiai 1: Shell Rsh I Figure 2F.5. Seafloor characterization from ROY photo stations for monitoring Site 1. Symbols show station 

lines are 1-rn bathymetric contours for reference. Each panel describes a different characteristic fro

The sides of each box are 300 m in length.
326

Figure 2F.6. Ternary diagrams showing the composition of Cruise 1C grab samples. At top, all

samples are plotted on a sand-clay-silt diagram with values normalized afier removal

of the gravel fraction. At bottom, silt and clay are grouped (mud) and the gravel-size

fraction is considered.
327

When the samples are plotted on a gravel-sand-mud (silt + clay) ternary diagram, the distribution

shows greater scatter (Figure 2F.6). The samples still plot closest to the sand apex, but gravel

concentrations range up to about 35%. This diagram shows that the greatest distinction in sediment

character is the gravel fraction. This component typically consists of carbonate and shell fragments

in addition to other biologic debris. It is typically greatest for samples near the larger mounds.

Sediment Dynamics

CTD casts show that particle concentrations are higher and salinity lower from east to west across

the study area. This is consistent with the input of fresh, sediment-laden water from the Mississippi

River. Nepheloid layers are present at most sites at most times. The nepheloid layers tend to be

saltier and colder than surrounding water. Although benthic nepheloid layers are almost always

observed, an intermediate layer is sometimes observed and the spatial and temporal variability is

high. This indicates that the advective transport of sediment is important in the region.

Sediment traps show a steep mass flux gradient with the greatest mass flux at the nearest trap to the

seafloor (Figure 2F.7). The logarithmic increase in mass flux to the bottom indicates significant

resuspension of sediments at these stations. Temporal variability was large, with the highest fluxes

recorded during January - May 1998 at Monitoring sites 4 (Megasite 2), 5 (Megasite 3) and 9

(Megasite 4), whereas fluxes at Monitoring Site 1 (Megasite 1) were highest during July - October

1997. The global average flux (all traps at all stations) was almost three times higher during the

January - May 1998 sampling period than during the other periods.

SUMMARY

Geologic characteristics of carbonate mounds at five locations on the Mississippi-Alabama outer

continental shelf have been assessed by the collection high-resolution geologic and geophysical data.

Digital side-scan sonar data were collected to show mound morphology and sediment textural

variations in addition to providing 100% bathymetric coverage. From these data a sonar mosaic and

bathymetry map was made for each study site. The mosaics show mounds ranging in diameter from

meters to hundreds of meters. The mounds are typically subcircular, but sometimes elongated or

irregular. Acoustically-reflective sediments are associated with many mounds and the preferential

occurrence of these sediments on the southwest sides of many mounds implies a relationship to

current action. Bathymetry data show mounds ranging in height up to more than 10 m and occurring

in tight to looser clusters. These data also indicate that many mound clusters occur along isobaths

and that some restrict or dam sediment movement southward across the shelf. Seismic reflection

profiles were also collected during along sonar track-lines to help with geologic interpretation and

to show surficial sediment layers. These data suggest recent sedimentation has been relatively

uniform throughout the region surveyed. Grab samples were collected to examine sediment grain

sizes in comparison with the sonar mosaics. The grain size results show a three component system:

a relict siliceous sand infiltrated by clay (probably from the Mississippi River) and gravel-size

calcareous debris, shell fragments, and other biogenic material from the carbonate mounds. Close-up

photographs and videos were taken of the seafloor using an ROV at each of nine monitoring sites

and have been used to classify sea bottom characteristics. They show highly variable substrate
328

Meters

Above

Bottom

1: 5

i a

May - July 97

July - Oct. 97

Oct 97 - Jan 98

1 JJ: -1 j;j

Jan - May 98

15 + +±+

E3uIk Flux (g/rn2/day)

1 1A

1-lB

4-i2 --5 I

9 - 1

o

- i:iC

i :3 -- 5

± 1-A + 1-L + 1 -

Figure 2F.7. Mass fluxes recorded in sediment traps during the four sampling periods of the first

year of sampling (May 1997 to May 1998). Note the logarithmic flux scale.

0 1-2A

0--- 1-2E3

jO--- 1 2C

fl 1-1è2

+1-±± +

a

1 00 1 000 1 c:a CJ
329

characteristics around the mounds. Conductivity and temperature profiles and optical backscatter

results collected at each of the monitoring sites show that nepheloid layers are prevalent, particularly

near the seafloor. Sediment traps show a large particulate flux close to the sea bottom, consistent

with significant resuspension. Together these results imply that advection is an important factor in

outer shelf sedimentation. The overall picture given by this study is of a geologically complex and

hydrographically-active regime.

REFERENCES

Brooks, J. M., ed. 1991. Mississippi-Alabama Continental Shelf Ecosystem Study: Data Summary

and Synthesis, Volume I; Executive Summary, Volume II: Technical Narrative, Volume III:

Appendices, Part 1 (Appendices A-D), Volume III: Part 2, (Appendix E), OCS Study MMS 91-

0062 (I), 91-0063 (II), 91-0064 (Ill). U.S. Department of the Interior. Minerals Mgmt. Service,

Gulf of Mexico OCS Regional Office, New Orleans, LA., 43 pp.(I), 862pp. (II), 1001 pp. (Ill-i),

and 1001 pp. (111-2).

Continental Shelf Associates, 1992. Mississippi-Alabama Shelf Pinnacle Trend Habitat Mapping

Study. U.S. Dept. Interior, Minerals Management Service, Gulf of Mexico OCS Region, New

Orleans, LA. 75 pp.

Coleman, J.M., H.H. Roberts, and W.R. Bryant, 1991. Late Quaternary sedimentation, pp. 325-3 52.

In A. Salvador, ed. The Gulf of Mexico Basin, Decade of North American Geology, v. J.

Boulder, CU: Geological Society of America.

Doyle, L.J. and T.N. Sparks, 1980. Sediments of the Mississippi, Alabama, and Florida (MAFLA)

continental shelf. Journal of Sedimentary Petrology 50:905-9 16.

Johnson, H.P. and M. Helferty, 1990. The Geological Interpretation of Side-Scan Sonar. Reviews

of Geophysics 28:357-3 80.

Kindinger, J.L., 1988. Seismic stratigraphy of the Mississippi-Alabama shelf and upper continental

slope. Marine Geology 83:79-94.

Kindinger, J.L., 1989. Depositional history of the Lagniappe Delta, Northern Gulf of Mexico. GeoMarine Letters 9:59-66.

Ludwick, J.C., 1964. Sediments in the northeastern Gulf of Mexico, p. 204-238. In R.L. Miller, ed.

Papers in Marine Geology. New York, NY: MacMillan.

Ludwick, J.C. and W.R. Walton, 1957. Shelf-edge, calcareous prominences in northeastern Gulf of

Mexico. American Association of Petroleum Geologists Bulletin 41:2054-2101.
330

McBride, R.A. and M.R., Byrnes, 1995. Surficial sediments and morphology of the southwestern

Alabamalwestern Florida panhandle coast and shelf. Transactions Gulf Coast Association of

Geological Societies 45:393-404.

Mitchum, R.M., P.R. Vail, and J.B. Sangree, 1977. Seismic stratigraphy and global changes of sea

level. Part 6: stratigraphic interpretation of seismic reflection patternsin depositional sequences,

pp. 117-134. In C. E. Payton, ed., Seismic stratigraphy: applications to hydrocarbon exploration,

Memoir 26. Tulsa, OK: American Association of Petroleum Geologists.

Sager, W.W., W.W. Schroeder, J.S. Laswell, K.S. Davis, R. Rezak, and S.R. Gittings, 1992.

Topographic features of the Mississippi-Alabama outer continental shelf and their implications

for sea level fluctuations during the Late Pleistocene-Holocene transgression. Geo-Marine

Letters 12:41-48.

Sager, W.W., W.W. Schroeder, K.S. Davis, and R. Rezak,submitted. A Tale of Two Deltas: Seismic

Mapping of Near Surface Sediments on the Mississippi-Alabama Outer Shelf and Implications

for Recent Sea Level Fluctuations, Marine Geology.

Shepard, F. P., 1956. Marginal sediments of the Mississippi Delta, American Association of

Petroleum Geologists Bulletin 40:2537-2623.

Sydow, 3. and H.H. Roberts, 1994. Stratigraphic Framework of a late Pleistocene shelf-edge delta,

Northeast Gulf of Mexico. American Association of Petroleum Geologists Bulletin 78:1276-

13 12.

Dr. William Sager is a professor in the departments of Oceanography and Geology & Geophysics

at Texas A&M University. He received a B.S. in physics from Duke University in 1976 and M.S.

and Ph. D. degrees in geology & geophysics from the University of Hawaii in 1979 and 1983. His

research interests include plate tectonics, paleomagnetism, marine geology and geophysics and highresolution seafloor mapping.

Dr. William Schroeder is a professor in the Marine Science Program atthe University of Alabama,

Dauphin Island, Alabama. He received his B.S. in zoology, with minors in geology and chemistry,

from San Diego State College in 1965 and his Ph.D. in oceanography at Texas A&M University in

1971. He has been involved in oceanographic investigations for over 34 years. His research interests

center on interdisciplinary studies with emphasis on relationships between the geologic, physical and

biologic regimes.

Dr. Ian R. MacDonald received a Ph.D. in oceanography in 1990 from Texas A&M University and

is presently an Associate Research Scientist at the Geochemical and EnvironmentalResearch Group

of Texas A&M University. MacDonald's primary research interest is the application of imaging and
331

GIS techniques for marine ecology. He is the program manager for the Stability and Change in Gulf

of Mexico Chemosynthetic Communities Program.

Dr. Ian Walsh is an associate professor (seniorresearch) in the College of Oceanic and Atmospheric

Sciences at Oregon State University. He received a B.S. in geology from Case Institute of

Technology, Case Western Reserve University in 1981, a M.S. in marine geology from Oregon State

University in 1986 and a Ph.D. in oceanography from Texas A&M in 1990. His research interests

include particle dynamics, biogeochemical cycling and physical forcing ofbiogeochemical processes.

NORTHEASTERN GULF OF MEXICO COASTAL AND MARINE ECOSYSTEM

PROGRAM: ECOSYSTEM MONITORINGPHYSICAL OCEANOGRAPHY AND

HYDROGRAPHY IN THE MISSISSIPPIIALABAMA PINNACLE TREND AREA

DURING MAY 1997 THROUGH APRIL 1998 AND DURING SEPTEMBER 1998

Mr. F.J. Kelly

Dr. Norman L. Guinasso, Jr.

Mr. Linwood L. Lee, III

Geochemical and Environmental Research Group

College of Geo sciences

Texas A&M University

INTRODUCTION

The "Northeastern Gulf of Mexico Coastal and Marine Ecosystem Program: Ecosystem Monitoring,

MississippilAlabama Shell" is being conducted by Continental Shelf Associates, Inc. and the

Geochemical and Environmental Research Group of Texas A&M University,for the U.S. Geological

Survey (USGS), Biological Resource Division. The purpose of the physical oceanography and

hydrography component of the program is to monitor environmental conditions at four of the

topographic features in the study area (Figure 2F.8) so that other work elements can relate observed

changes in community structure and zonation to changes in environmental conditions. The first year

of observations from the moorings, May 97 - April 98, reveals the principal features of the flow field

and the environmental parameters: temperature, salinity, turbidity, and dissolved oxygen.

Observations during September 1998 were unique to the study thus far because of the passages of

Hurricanes Earl and Georges and a 10-day period of persistent flow that suggests the intrusion of

oceanic mesoscale flow onto the shelf.

METHODS AND RESULTS

Six physical oceanographic/sediment dynamics moorings were installed on 22-24 May 1997. Three

moorings were installed at Site 1, and one each at Sites 4, 5, and 9 (Figure 2F.8). Each site will have

at least one oceanographic mooring in place throughout the study. Two of the three moorings at Site
332

I

Legend

I M egesile

=Slte

CENTRAL

EASTERN

LOCATION MAP

Gulf of Mexico

Figure 2F.8. Map showing the locations of the four sites at which instrument moorings are

located. Site 1 is in Megasite 1; Site 4 is in Megasite 2; Site 5 is in Megasite 3; and

Site 9 is in Megasite 5.

1 are "re-locatable" and were subsequently moved to Site 5 on 1 May 1998. Each mooring includes

current meters, with temperature and conductivity sensors, at 4 and 16 meters above bottom (mab),

sediment traps at 2, 7, and 15 mab, and an instrument at 2 mab that measures temperature,

conductivity, DO, and turbidity.

The currents at 16 mab represent the mesoscale flow just above the pinnacles. This height is above

the bottom Ekman layer. The larger pinnacles may slightly perturb the flow, a possibility that will

be examined during the synthesis phase of the project. Across the entire pinnacle study region
333

substantial similarity exists in the observed flow field. For example, Figure 2F.9 summarizes the

current velocity observations at Site 1 A (the northeastside of the pinnacle) over one year. The figure

displays basic statistics, a scatter plot, and a table ofjoint frequency for speed and direction, which

is the tabular version of a current rose. The most frequent direction octant and the direction of the

vector mean current is northeast. The most frequent speed range is 5-10 cm/s, reflecting the normal

tidal influence. Strong currents, i.e., greater than 35 cmls, are most frequently directed to the

southwest. The maximum currents at 16 mab approached 50 cmls during the first year. Compared

with the flow at 16 mab, the near-bottom flow at 4 mab was more site-specific. Bottom friction and

the local topography influenced flow. The most frequent direction octants were those with a

southerly component. Average scalar speeds were comparable at times to those at 16 mab, and mean

vector speeds at some sites exceeded the overlying flow because of greater directionality.

Times series of dissolved oxygen and turbidity were collected at each mooring at 2.3 mab. Dissolved

oxygen values were generally near or above 4 mg/L, except at Site 5 during the second deployment

period. In this record, values were below 3.0 mg/L much of the time and fell below 2.0 mg/L during

18 to 28 August and 5 to 13 September 1997. Turbidityvalues at all sites were generally quite low,

i.e., 0 to 2 NTU, with brief periods during which turbidity rose the 2 to 10 NTU range.

Temperature from the instrument moorings followed a small seasonal cycle with superposed

variability caused by advective changes from tidal and inertial currents and possible intrusions by

mesoscale water mass motion. Salinity ranged from about 34.9 to 36.8 but generally was in the 36.2

to 36.4 range. Values above 36.5 suggest possible intrusion of Loop Current related water.

CTD casts were taken during each of the monitoring and servicing cruises to assess the vertical

profiles of salinity, temperature, photosynthetically-active radiation (PAR), transmissivity,

backscattered light, and oxygen concentrations. During the monitoring cruises three profiles were

generally taken around each site to assess variability at each site. In general, profiles at each site

differed very little from one another. Figure 2F. 10 summarizes the temperature-salinity relationships

for the five cruises in the first year of the program. A composite T-S plot is given for each cruise

(Figure 2F.lOa-e), and for all casts of all cruises (Figure 2F.lOf).

In May 1997 (Figure 2F.lOa) salinity reached a maximum of about 36.5, which is typical of the

upper waters of much of the Gulf of Mexico. In the upper part of the water column, the profiles at

the shallower Sites 5 and 6 exhibited the coolest and freshest water, while the profiles at Sites 7, 8,.

and 9, which are closest to the Mississippi Delta, showed warmer fresh water. In July 1997 (Figure

2F. lob), all sites show little influence from fresh water. Fresher waters were again present in October

1997 (Figure 2F. 1 Oc), and all sites showed evidence of cooling. Colder waters in the upper layers

were found at Sites 7, 8, and 9 and, interestingly, at Site 4. Warnier fresher waters were found at the

other sites.

By January 1998 (Figure 2F.lOd) all water temperatures were below 21C, and maximum salinities

also decreased. Bottom salinities at many stations were below 36.0. This correlates well with the

lower salinities recorded by the current meters during the third deployment period. In April 1998

(Figure 2F. 1 Oe), the upper waters were slightly warmer and much fresher. The freshest water was
334

V (North)

40cm s (interval: 10 cm 1)

U (East)

Figure 2F.9. Summary of current meter observations at Site 1A at 16 meters above the bottom

(mab) for the period 23 May 1997 through 24 April 1998: Basic statistics (top),

scatter plot (middle), and percent joint occurrence of speed and direction (bottom).

N NE E SE S SW W NW TOTAL

c 5 1.73 3.02 4.49 2.55 2.59 3.88 4.91 2.58 25.74

5 - 2.0 1.84 4.30 5.12 2.53 2.85 4.25 4.63 2.67 28.18

10 - 15 0.93. 2.77 3.74 1.09 1.66 2.13 2.55 1.13 15.98

15 - 20 050 3.65 4.59 0.65 0.69 1.87 1.81 0.69 14.45

20 - 25 0.29 2.81. 4.29 0.30 0.16 0.89 1.30 0.24 10.28

25 - 30 0.11 0.67 1.33 0.04 0.02 0.64 0.51 0.15 3.46

30 - 35 0.02 0.22 0.64 0.01 0.02 0.31 0.3.3 0.03 1.38

> 35 0.00 0.07 0.12 0.01 0.02 0.26 0.04 0.01 0.52

TOTAL 5.41 17.50 24.31 7.17 8.01 14.23 15.88 7.50

C1A1 - L6 mab

START TIME: 05/23/1997 04:30 STOP TIME: 04/24/1998 15:00 GMT

Num ptg. Mean Std Day Minimum Maximum

SPEED: 14105 11.12 7.91 1.10 49.60

U CO: 14105 2.80 11.24 -45.07 40.02

V COMP: 14105 0.60 7.19 -36.36 29.87

MEAN CURRENT VECTOR: 2.86 cm s @ 77.9° True

*
335

Figure 2F. 10. Temperature-salinity relationships for the five cruises in the first year of the program

A composite T-S plot is given for each cruise (3a-e), and for all casts of all

cruises (3f).

35 , Cue 2 JuIy 1997) CrwsL 1 Ma ug7)

30 30-

20 20

IS' -4 L -.-.-.- 15'

2 30 Z2 34 36 38 28

_ _.30 32 34 36 38

Sanity Sairiity

35 35

CrUise 3 fOcthber 1991) (ruse 4 Jantary 19981

30 -. :c 2

ii -.- a) - E

- 25-

20-

-- i5'

29 30 32 34 36 38 29 30 '32 36 38

SaIrty

5 - 5.

Cruse 5 (ApUl. 1995) AU CrLIi

- ..,.. -'-. 25 E 2b - -- ----. -

' - I 20--,

- - 2o15 ', - - . 1 5 .,,.. -. ......I 28 '30 32 34 36 35 28 30 32 34 36 38

S 'Uri I
336

found at sites 4, 5, and 6 (lower cluster of points in Figure 2F.lOe). Sites 7, 8, and 9 forming the

middle cluster on this diagram with lower temperatures and salinities than at Sites 1, 2, and 3.

September 1998 was the most unusual month of the study thus far because of several events.

Hurricane Earl's path crossed the eastern side of the study area on September 3 and the eye of

Hurricane Georges passed directly over Site 5 on September 29. The resulting currents at 16 mab

are shown in stick vector form in Figure 2F. 11. Currents were strongest during Hurricane Georges.

At Site 1, speed reached 96.7 cmls. The direction of the hurricane driven currents was mainly

southwest at Sites 1 and 4, and shifted between southwest and northwest at Sites 5 and 9. During

Hurricane Earl, the response was about half that forced by Hurricane Georges, probably because

Hurricane Earl moved more quickly across the shelf. Betweenthe two events, an oceanic circulation

feature may have intruded onto the shelf. Currents were persistently southwestward during

September 11-21 at Sites 1 and 4, with speeds of 15-20 cmls. This signature was also observed at

Sites 5 and Site 9 for briefer periods.

The speeds recorded at 4 mab during September 1998 are shown in Figure 2F.12. The response to

Hurricane Earl at this depth was strongest at Site 1, reaching about 50 cmls, and almost nonexistent

at Site 4. During Hurricane Georges, the response was strongest at Site 4, reaching 60 cm/s. Since

the eye of Georges passed directly over Site 5, a barotropic response to sea level fluctuations is

exhibited by the near bottom current. The intrusion event between the hurricanes is most evident at

Site 4, where current speed exceeded 20 cmls for eight days. The effect of the strong bottom currents

during the hurricanes at Site 5 is shown in Figure 2F. 13. Only during these events do turbidity values

exceed normal background ranges.

SUMMARY

The statistics of currents measured at all sites measured are similar. The mostfrequent direction of

the currents in the region is aligned with the trend of the large scale topography. At 16 mab, the most

frequent current speeds are in the 5-10 cnils range, which reflects the normal tidal currents in the

region.

Hurricanes Earl and Georges forced large southwestward bottom currents, i.e., approximately 40-5 0

cmlsec for Earl and 90-100 cmlsec for Georges at 16 mab. At 4 mab the current speeds of 40-60

cmlsec were recorded.

Temperature and salinity profiles collected during five cruises in the first year of the program

delineate a seasonal cycle that shows a pattern of mixing between the lower salinityshelf waters and

higher salinity Gulf waters. Salinities rarely exceeded 36.5 and were often significantly reduced by

freshwater influx into the area. Temperatures were always in a range of 17-31 C during the CTD

casts. However, the bottom moored instruments recorded temperatures between 10.8 - 23.4C.
1 2 3 4 5 6 7 8 9 10 1112 13 14 15 16 17 18 19 20 21 22 September 1998 Figure 2F. 11. September 1998 stick vector plot of currents recorded at 16 meters above the bottom (mab) at S

North is vertically upward, and a scale for the magnitude is in the left side of each panel.
604020060402006040200604020 ilai 1AA A. Site CIA Site C4A Site C5C 4eMlh. iii4 AL. Site C9A 0 1 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 September 1998 Figure 2F.12. September 1998 current speeds recorded at 4 meters above the bottom (mab) at Sites 1, 4, 5, and 
200 150 10050 200 150 100500 20 27 July 1998 3 August Turbidity (NTU) - Site C5A 31 7 September 14 21 28 5 October 12 Figure 2F.13. Turbidity (NTU) recorded at Sites SA and 5B at 2.3 meters above the bottom during 20 July throu

1998. 10 17 24 Turbidity (NTU) - Site C5B / -
340

ACKNOWLEDGMENTS

This work was supported by the U.S. Department of the InteriorU.S. Geological Survey, Biological

Resources Division, under BRD Contract 1445-CTO9-96-0006, in cooperation with the Minerals

Management Service, Gulf of Mexico OCS Region. The cheerful cooperation and assistance of the

Captain and crew of the R/V Tommy Mumo is gratefully acknowledged.

Mr. F.J. Kelly is an Assistant Research Scientist in the Geochemical and Environmental Research

Group in the College of Geosciences at Texas A&M University. Mr. Kelly received his B.A. in

physics from the University of California, Berkeley and M.S. in oceanography from Texas A&M

University. He has been investigating the physical oceanography of the Gulf of Mexico and its

continental shelves for more than twenty years. Currently, he is the Principal Investigator for the

Texas Automated Buoy System (TABS). He has served as Principal Investigator for the physical

oceanography component of numerous projects, including the Mississippi-Alabama Marine

Ecosystem Study (MAMES) conducted for the MMS in 1987-1989.

Dr. Norman Guinasso, Jr. is Deputy Director for Ocean Sciences at the Geochemical and

Environmental Research Group, an element of the College of Geosciences at Texas A&M

University. He received his B. A. in physics in 1966 from San Jose State College and the Ph.D. in

oceanography from Texas A&M in 1984. He serves as Program Manager at Texas A&M for the

Texas Automated Buoy System and is a Principal Investigator on several MMS-sponsored programs

concerned with the oceanography of the Gulf of Mexico.

Linwood L. Lee, III is a Research Associate with the Ocean Sciences Division of the Geochemical

and Environmental Research Group at Texas A&M University. He is currently involved with the

Texas Automated Buoy System (TABS) and other physical oceanographic research projects in the

Gulf of Mexico and offshore West Africa. His research interests include coastal ocean and

continental shelf processes, real time data telemetry and oceanographic instrumentation.
NORTHEASTERN GULF OF MEXICO COASTAL AND MARINE ECOSYSTEM

PROGRAM: ECOSYSTEM MONITORING, MISSISSIPPI/ALABAMA SHELF;

HARD BOTTOM COMMUNITIES

Mr. David B. Snyder

Mr. Keith D. Spring

Mr. Bruce D. Graham

Mr. Steven T. Viada

Continental Shelf Associates, Inc.

Jupiter, Florida

Mr. Dane D. Hardin

Applied Marine Sciences

Santa Cruz, California

INTRODUCTION

A series of hard bottom features known as the Mississippi/Alabamapinnacle trend is the subject of

this ecosystem monitoring program which includes geological, biological, and physical

oceanographic study components. The primary biological component of the programis to describe

and monitor epibiotal communities associated with nine hard bottom features within the

Mississippi/Alabama pinnacle trend in water depths of 60 to 100 m (Figure 2F.14). A secondary

biological component is to monitor and describe the fishes associated with the pinnacle features. This

report describes preliminary results for epibiota and fishes from initial monitoring cruises.

OBJECTIVES

The objectives of this study component are as follows:

to describe hard bottom (epibiota and fishes) community structure and seasonal dynamics at

each site;

to identify differences in community structure among sites differing in relief (low, medium,

and high) and location (east, central, and west); and

to understand relationships between community structure and environmental variables such

as small-scale habitat variability, rock type, sediment cover, turbidity, and other geological

and oceanographic variables.

MATEPJALS AND METHODS

Hard bottom communities are being sampled at nine sites (Figure 2F.14) by remotely operated

vehicle (ROy). Sampling sites were chosen to fall within three categories of relief (low, medium,

and high) in three regions (eastern, central, and western). Site selection was based on data from

geophysical surveys and ROV reconnaissance surveys. At each site, random photographs are taken

341
1a I' 0 WESTERN t t 1 II Legend =Megaslte 'a =SIteCENTRAL II X.VPIIAPiA Gulf of Mexico EASTE

LOCATION 

ALA

.$AR

S H 

Figure 2F.14. Locations of final monitoring sites within the Mississippi/Alabama pinnacle trend in water depths 

0' I
343

and random video transects are being surveyed using ROV during each of four monitoring cruises.

Random photographs are used to estimate the abundances of sessile and motile epibiota, whereas

video images are used to quantify larger and more widely dispersed organisms, including fishes, and

to broadly characterize substrates and species composition. In addition, fixed video/photoquadrats

have been established that are resampled on subsequent cruises; the data will be used to describe

temporal changes related to growth, recruitment, competition, and mortality. Voucher specimens also

are being collected to aid in species identification. Together with geological and oceanographic data

collected during the program, these data will be analyzed and interpreted to describe hard bottom

community dynamics, variation within and among sites, and relationships between the biota and

physical variables. Frequency of occurrence of fishes is being recorded for the video transects made

while navigating to the random photograph locations. A master list of fish species for all sites is

being prepared from analysis of still and video photographic data. Four monitoring cruises have been

scheduled to complete the field tasks. To date, three of four monitoring cruises have been completed:

April 1997 (Cruise 1C), October 1997 (Cruise M2), and April 1998. At present, quantitative slide

analyses have been completed for the April 1997 cruise. Fish analyses have been completed for the

April and October 1997 cruises.

Percent cover, density, and diversity of epibiotal taxa are being estimated from quantitative

photographs using random dot overlays and direct counts of solitary taxa. These biotic variables

(particularly density) were related to physical variables using linear regressions. Associations among

dominant epibiotal taxa were investigated through pairwise product-moment correlation analysis.

For fishes, patterns of co-occurrence or association among taxa and similarity among stations were

related to pre-defined location (east, central, and west) and relief (low, medium, and high) categories

using multi variate analyses. These analyses included classification (cluster analysis) and

Correspondence Analysis (CA) ordination of the taxa-by-samples data matrix.

RESULTS AND DISCUSSION

Hard Bottom Communities

A total of 790 random photoquadrats was analyzed from Cruise 1C. Most sites had at least 98

photoquadrats for analysis, but all but six photographs at Site 9 were rejected due to turbidity.

Compiling the 10 most abundant taxa at each site yielded a list of 43 numerically dominant taxa.

Cnidaria was the most-represented phylum with 13 taxa of octocorals, 10 of ahennatypic corals, 4 of

antipatharians, and single taxa of herrnatypic corals and actinarians (anemones). Porifera was next

with five taxa, followed by Ectoprocta with four taxa. Ahermatypic corals had the highest mean

density of 327.97 organisms/rn2 over all sites, due to the numerical dominance of Rhizopsammia

manuelensis. Octocorals were second with 9.43 organisms/rn2, followed by poriferans, ectoprocts,

and antipatharians with 5.30, 3.17, and 2.75 organisms/rn2, respectively. Densities and numbers of

taxa at each site were highly variable.

Little of the biological variation among sites apparently is due to water depth, vertical re1ief, distance

from the Mississippi River, or suspended sediment flux. Only 8 of the 21 taxa recorded at six or

more sites had statistically significant regression coefficients for any of these physical variables, and
344

there was no consistent pattern to the results. However, density of the numerically dominant

R. manuelensis increased with proximity to the Mississippi River.

Significant correlations occurred between 20 pairs of taxa. Highly significant correlations among

Antipathesfurcata, Ellisella sp., and the large white solitary scieractinian are probably the result of

their common significant positive association with depth. The tan-purple solitary scleractinian, the

white solitary seleractinian, Paracyathuspuichellus, and Madracis myriaster also were significantly

correlated, but with no apparent effect of the four physical variables.

Despite the preliminary nature of the results, several findings conflict with those reported by others.

For example, Gittings et al. (1992) reported abundances of Rhizopsammia, and overall organism

abundances were positively related to distance from the Mississippi River at a range of 27 to 70 km.

The new data indicate, however, that abundances of this species and the combined densities of the

43 dominant taxa are negatively related to distance from the river at a range of 70 to 145 km. It is

not known whether this contradiction is enigmatic or whether it indicates abundance maxima at

approximately 70 km from the Mississippi River. Also, the results do not indicate increases in the

density of epibiota or number of taxa with increasing vertical relief. However, this preliminary

analysis focused on between-site variations, whereas the physical and biological variations within

sites may be nearly as large as those between sites. The more detailed statistical analyses planned

for future reports should help address these questions.

Fish Communities

Analysis of videotapes from Cruises M2 and 1C revealed 78 fish taxa in 27 families The most

speciose families were sea basses (Senanidae), squirrelfishes (Holocentridae), lizardfishes

(Synodontidae),jacks (Carangidae), wrasses (Labridae), and butterflyfishes (Chaetodontidae). The

most frequently occurring taxa in the videotapes were roughtongue bass (Pronotogrammus

martinicensis), short bigeye (Pristigenys alta), bank butterflyfish (Chaetodon aya), red barbier

(Hemanthias vivanus), and tattler (Serranus phoebe). These taxa represent the deep reef fish

assemblage reported for water depths of 50 to 100 mill the western Atlantic. Similar species have

been reported by previous investigations of the pinnacle features (e.g., Continental Shelf Associates,

Inc. 1985; Brooks 1991). These species represent deep reef assemblages similar to those described

for other portions of the Gulf of Mexico (e.g., Shipp and Hopkins 1978; Dennis and Bright 1988)

and off the southeastern U.S. coast (Parker and Ross 1986).

Taxonomic richness recorded from videotapes for each cruise differed across all sites. During Cruise

1C the number of taxa observed ranged from 5 at Site 9 to 22 at Site 7 and averaged 15.3 taxa per

site. Cruise M2 yielded an average of 20.7 taxa per site with a range of 13 taxa from Site 6 and 30

taxa from Site 1. The correlation between average depth at each site and number of taxa was (r0.55)

for Cruise 1C and (r=0.69) for Cruise M2.

Video transects from Cruise 1 C yielded 44 taxa compared to those taken during Cruise M2, which

produced 67 taxa. The similarity in taxonomic composition measured by the Phi coefficient for each

site between the two cruises ranged from 0.30 at Site 4 to 0.51 at Site 2. The most frequently
345

occurring taxa showed similar patterns across sites between cruises. Cluster analysis did not resolve

distinctive patterns with respect to location and relief. Ordination showed some weak differences

related to location, with eastern samples separating from the central and western samples. Also,

western samples showed more variability than the eastern and central samples. Qualitative data on

the scale of the study area as used here may be too coarse to resolve any differences of similarities

that may exist among the sites, with respect to depth or location. A closer examination, at the level

of transects within sites along with an analysis of substrate preference of the dominant species, will

be undertaken in the final synthesis report.

REFERENCES

Brooks, J.M., ed. 1991. Mississippi-Alabama Continental Shelf Ecosystem Study Data Summary

and Synthesis. OCS Study MMS 91-0063. U.S. Department of the Interior, Minerals

Management Service, Gulf of Mexico OCS Regional Office, New Orleans, La.

Continental Shelf Associates, Inc. 1985. Live-bottom survey of drilisite locations in Destin

Dome Area Block 617. Report to Chevron U.S.A. Inc. 40 pp. + app.

Dennis, G.D. and T.J. Bright. 1988. Reef fish assemblages on hard banks in the northwestern Gulf

of Mexico. Bull. Mar. Sci. 43(2):280-307.

Gittings, S.R., T.J. Bright, W.W. Schroeder, W.W. Sager, J.S. Laswell, and R. Rezak. 1992.

Invertebrate assemblages and ecological controls on topographic features in the northeastern Gulf

of Mexico. Bull. Mar. Sci. 50(3):435-455.

Parker, R.O. and S.W. Ross. 1986. Observing reef fishes from submersibles off North Carolina.

N.E. Gulf Sci. 8(1):31-50.

Shipp, R.L. and T.S. Hopkins. 1978. Physical and biological observations of the northern rim of the

De Soto Canyon made from a research submersible. N.E. Gulf Sci. 2(2):113-121.

Mr. David B. Snyder is a senior staff scientist with Continental Shelf Associates, Inc. He has 15

years of experience with aquatic environmental assessment and research programs for federal, state,

and industrial clients. He has participated as Research or Chief Scientist on over 50 scientific cruises

conducted in domestic and international waters. Mr. Snyder has managed several fishery-related

projects including bycatch studies, life history studies, and ichthyofaunal assessments in a variety

of marine and freshwater habitats. Mr. Snyder received his B.S. in zoology from the University of

Florida in 1978 and his M.S. in ichthyology/marine biology from Florida Atlantic University in

1984.

Mr. Dane D. Hardin, a senior scientist for Applied Marine Sciences, Inc., has pioneered the

application of quantitative biometric techniques to rocky epibenthic communities, both intertidal and
346

subtidal. These techniques have included utilization of manned submersibles and remotely operated

vehicles (ROV) for photographic sampling of deep reef communities on the outer continental shelf

(OCS). These methods are now standard on the California OCS for determining impacts on reef

communities caused by oil development operations, and are presently being used on the Minerals

Management Service (MMS) long-term monitoring study (CAMP Phase II) which was conducted

in the Santa Maria Basin. Mr. Hardin received his B .A. from the University of California, Santa Cruz

in 1967.

MT. Spring is a senior scientist with Continental Shelf Associates, Inc. He has over 18 years of

oceanographic and environmental science experience. He has served as Project Manager on

numerous complex oceanographic studies, including multidisciplinary baseline studies,

photodocumentation surveys, site clearance studies, and environmental monitoring programs for

offshore drilling and dredged material disposal. He has served as Chief Scientist on more than

80 oceanographic surveys in the Gulf of Mexico, off the east coast of Florida, and within the

Caribbean. Mr. Spring received his B.S. in biological sciences from S.U.N.Y. at Brockport and his

M.S. in biological oceanography from Florida Institute of Technology in 1981.

Mr. Graham is a senior staff scientist with Continental Shelf Associates, Inc. He has extensive

experience in field studies of marine benthic communities. He has served as Project Manager and/or

Chief Scientist on numerous oceanographic studies, including multidisciplinary baseline studies,

photodocumentation surveys, and environmentalmonitoring programs. He has been responsible for

the analyses of more than 9,000 quantitative/ qualitative photographs of hard and soft bottom

collected in areas that include the Gulf of Mexico. Mr. Graham received his M.S. in Biological

Sciences from Florida Institute of Technology in 1983 and his B.S. in Biological Sciences from the

University of New Hampshire at Durham in 1979.

Mr. Viada specializes in the ecology ofbenthic communities. He has had over 18 years of experience

utilizing techniques of photography for the qualitative and quantitative analysis of benthic

communities throughout the Gulf of Mexico, Alaska, California, the Sea of Okhotsk (offshore

Sakhalin Island, Russia), the United Arab Emirates, Australia, the Bahamas, and the Caribbean. He

also has over 18 years of experience as a specialist with the taxonomic identifications of Scleractinia

and Octocorallia (stony corals and soft corals, respectively) within these localities. Mr. Viada

received his M.S. in Biological Oceanography from Texas A&M University in 1980, and his B.S.

in Zoology from Texas A&M University in 1978.
EPIBIONT RECRUITMENT

Dr. Paul Montagna

Ms. Tara Holmberg

University of Texas Marine Science Institute

Port Aransas, Texas

OBJECTIVES

The goal of the companion study is to support the descriptive and monitoring portions of the program

with experiments (based on testablehypotheses) that define ecological mechanisms responsible for

spatial and temporal differences in hard bottom epifauna communities.

INTRODUCTION

Spatial and temporal variations of hard bottom communities are functional responses to biotic and

abiotic processes. There are primarily three biological processes: recruitment, competition, and

predation. Abiotic processes effecting spatial and temporal variability in shallow coastal zones are

known to include seasonal temperature and salinity changes, desiccation, abrasion due to waves,

turbidity due to resuspended sediments, turbulence, and stochastic disturbance events. In deep water

(e.g., the Pinnacle Habitat), temperature, salinity, and desiccation are not important determinants,

but abrasion, turbidity, turbulence, and stochastic disturbance events may play an important role in

the distribution of epibiont abundance and biomass. The ecological processes affecting standing

stocks and recruitment are jointly classified as disturbance. These processes are both physical and

biological in origin, but distinguishing between the two in field experiments is difficult. For

example, cages exclude predators, but disrupt normal water flow over settling surfaces. In the current

study, water flow disruption was isolated, but other processes (e.g., predation and competition, and

abrasion) were unseparated and are called disturbance.

EXPEPJMENTAL DESIGN

Settling plate experiments with exclusion, settlement, and control treatments were used to study the

biotic and abiotic interactions that regulate growth and settlement of epibiont communities. The

settling plates are attached to a mooring, and the entire device is called a "biomooring." There are

two maj or deployments: one for a spatial and one for a temporal study. The maj or elements of the

settling plate experiment studies are

Spatial study at four stations to last for one year

Replication of the spatial study during the second year

Two settling surface treatments: hard and soft

Three settling plate treatments: uncaged, caged, and partially-caged

347
348

Three heights, or distances, from the bottom (0 m, 2 m, 13 m)

Time series study at one station, three cruises over two years

The temporal study at Site 4 consists ofeight biomoorings and was designed to test for differences

in recruitment and growth over time. Originally, quarterly retrievals of one biomooring each over

a 2-year period were scheduled. Because of sampling difficulties and logistical problems, one cruise

per year has been allotted for retrieval of the temporal samples. The slow recruitment rates observed

from the first set of samples indicate that the longer time period improved the design. Sampling more

frequently would not have detected differences among treatments because of the slow growth rates.

The spatial experiment is designed to test for differences among habitats. One biomooring was

deployed at pinnacle Sites 1, 4, 5, and 9 at approximately the same water depth. This experiment is

proceeding as originally planned.

The first deployments of biomoorings are resting on the bottom (0 m height) because of shackle

failure. The second deployments of biomoorings were suspended at the planned heights of-2 mand

13 m from the bottom. This change enhances the project because we are now sampling three

heights from the bottom (0 m, 2 m, 13 m). Recruitment may be more likely to occur at habitat

surfaces, so the 0 m height may yield different results from those suspended ill water.

FIELD METHODS

Settling plates are arranged in three experimental treatments: an uncaged treatment, a caged

treatment, and a partially-caged control treatment. The uncaged settling plate measures net

recruitment with biotic and abiotic interactions. This includes gross larval settlement, recruitment,

growth, community development, and losses due to predation and disturbance. The caged settling

plate is the experimental treatment to exclude ecological effects due to predation and disturbance.

A common problem with enclosures is that water flow at the settling plate surface is changed.

Therefore, a cage-control treatment is added to subtract effects due to the enclosure. This control is

a partial cage that would have the same effects on water flow, but would allow predators access to

the experimental treatment. Thus, the control treatment includes net recruitment in addition to water

flow interactions. The effects on rates of recruitment by ecological processes, water flow, and net

recruitment are then calculated by subtraction of the experimental treatments.

The three experimental treatments (uncaged, caged, and partially-caged control) are attached to one

another forming a "Y"-shaped triad. Each treatment consistsof four settling plates, or replicates, that

has been attached to the triad. Three of the replicate settling plates are hard surfaces made of ceramic

tiles and the other is a soft surface made of outdoor carpet. Each biomooring consists of an anchor,

six triads, and a float. A common pitfall in these types of experiments is pseudoreplication, where

the treatment levels (uncaged, caged, and partially-caged control) are not replicated. To avoid

pseudoreplication, there are three replicate triads at two different depths on each biomooring. The

replicate treatments have been placed on the wire so that there is no vertical bias in sampling. Each

triad contains 12 settling plate replicates (3 experimental treatment replicates x 4 plate replicates).
349

Together, each depth treatment consists of 36 samples (3 treatments x 3 replicate treatments x 4 subtreatment replicates).

LABORATORY METHODS

Settling plates are scored for abundance as per cent cover by both colonial and non-colonial

organisms to the lowest taxonomic level possible. In many cases, identification is to the phylum level

as many organisms are newly settled. Many larval forms have similar morphologies or characteristics

and do not have adult characteristics that allow differentiation. For example, many species of

bryozoans and hydroids both have stoloniferous morphology. The stolons may extend for several

centimeters without any unique, identifiable characteristic to distinguish the two phyla. In addition,

there are many unknown taxa, which are mostly gelatinous organisms without structures or are

recently settled larvae without distinguishing features.

A

14-mm2 mesh grid is placed over the plate. The outer 7.5 mm edge is not scored to account for

possible inconsistencies in the actual surface area exposed. By using a mesh grid, the 3-D coverage

is scored accurately. The settlement plates are analyzed using a dissecting microscope at 250x

magnification.

It is likely that some organisms settling on the plates are new to science. There has not been much

systematic work done in this region of the Gulf of Mexico on small, epibiont, deep water organisms.

As the Pinnacle Habitat is unique, it is quite likely that there are several new endemic species.

RESULTS

The first time-series biomoorings were deployed in May 1997, and a single biomooring from site 4

was retrieved in October 1997. The biomass of organisms is small and total coverage of organic

matter is extensive. The organic matter is primarily due to stoloniferous bryozoan and hydroid

colonies that comprise an average of 72% of total coverage by stolons on the settlementplates (Table

2F.2). While the sample size was too small to calculate statistical significance, coverage by all taxa

except the uncolonized and Rhizopoda decreased in the uncaged and partial cage treatments(Table

2F.3). Most taxa appear to be limited by either water flow, disturbance, or both, but Rhizopoda

recruitment appears to be enhanced (Table 2F.4). Gross recruitment rates over time are highest for

bryozoans and hydroids and lowest for non-colonial organisms.

CONCLUSIONS

Gross recruitment rates are very slow whiletotal coverage on settlement plates was high. Coverage

was comprised almost entirely of small, stoloniferous, colonial organisms. There were also low

numbers of annelids and other larger organisms (Table 2F.2). The plates contained an early stage

succession community. Generally, early succession communities are characterized by low diversity,

opportunistic (or r-selected) species, high growth rates, and small animals (Odum 1969, Rhoads et

al. 1978). In contrast, late succession communities are characterized by high diversity, specialized
350

Table 2F.4. Coverage changes due to ecological processes.

Processes (cm2/O.5 yr)

Taxa I?low Disturbance Gross

Recruitment

Stolon -1.68 -3.27 72.01

Cnidaria 5.93 -26.13 41.21

Bryozoa -2.75 -7.65 31.41

Mollusca 0.84 -0.05 0.33

Annelida -1.49 -3.55 5.04

Rhizopoda 12.18 28.14 -6.44

Uncolonized -2.05 1.12 2.05

Unknown (8) -6.72 -0.56 40.60

Table 2F.3 Standing stock coverage by treatments after 6 months.

Taxa

% Coverage

Caged Uncaged Partial Cage

Stolon 80.37 78.56 57.49

Cnidaria 53.87 17.23 18.00

Bryozoa 32.75 27.15 18.00

Mollusca 1.33 0.32 0.96

Annelida 4.05 1.71 0.00

Rhizopoda 6.56 24.80 29.05

Uncolonized 0.00 3.63 0.96

Unknown (8) 38.72 45.76 28.57

Table 2F.2. Mean coverage by taxa for all treatments after 6 months.

Taxa Mean Coverage (%)

Stolon 72.14

Cnidaria 29.70

Bryozoa 25.97

Mollusca 0.87

Annelida 1.92

Rhizopoda 20.14

Uncolonized 1.53

Unknown (8) 37.68
351

slow-growing (or k-selected), and large species (Odum 1969, Rhoads et al. 1978). Community

succession on deep seahard bottoms will be slow compared to coastal areas (Levin and Smith 1984).

In the pinnacle habitat, settlement rates of larvae will decrease with depth and distance from shore

(DePalma 1972). It will most likely take several years before a late-stage successional community

will be observed on the current settling plates.

Several differences were noted betweentreatments. All taxa except Rhizopoda and the uncolonized

category decreased in the uncaged and partial cage treatments where predation was present (Table

2F 3) Rhizopoda was enhanced, not negatively affected, by predation. It may be that foraminifera

were able to take advantage to settle in the free space left when other organisms were grazed upon.

Because uncolonized areas were more abundant in the uncaged and partial caged treatments, it is

likely that predation enhances diversity by opening up more settlement area.

Most of the organisms appeared to be affected by small-scale turbulence produced by the caging

material and disturbance, because nearly all had negative recruitment rates due to flow and

disturbance processes (Table 2F.4). This is not surprising, because small scale turbulence is known

to affect vertical and horizontal distributions of organisms in deepwater environments (Mullineaux

1989). While gross recruitment rates over time are very low for Rhizopoda, the settlement of these

organisms is enhanced by the processes which limit other organisms. It may be that flow allows these

very small organisms to collect in eddies and gives them extra time to settle while disturbance clears

space for settlement.

At this point, all conclusions are preliminary because of low sample sizes, and difficulty in

identification of larval stages and organisms without visible identifying characteristics. Jnitial

analyses, however, have indicated interesting trends that may prove to represent generalities in the

future.

REFERENCES

Odum, E.P. 1969. The strategy of ecosystem development. Science 164:262-270.

Rhoads, D.C., P.L. McCall, and J.Y. Yingst. 1978. Disturbance and production on the estuarmne sea

floor. Am. Sci. 66:577-586.

Levin, L.A. and C.R. Smith. 1984. Response of background fauna to disturbance and enrichment in

the deep sea: a sediment tray experiment. Deep Sea Res. 31:1277-1285.

DePalma, J.R. 1972. Fearless fouling forecasting, pp. 865-879. In Proceedings of the Third

International Congress on Marine Corrosion and Biofouling. National Bureau of Standards,

Washington, D.C.

Mullineaux, L.S. 1989. Vertical distributions of the epifauna on manganese nodules: implications

for settlement and feeding. Limnol. Oceanogr. 34:1247-1262.
352

Dr. Paul Montagna is an Associate Professor in the Department of marine science and Research

Scientist at the University of Texas Marine Science Institute. He has worked at the MSI since 1986.

He has been working in the field of benthic ecology since 1973, focusing on population and

community ecology and trophic dynamics. Dr. Montagna received his B.S. in biology from SUNY

Stony Brook, a M.S. in biology from Northeastern University, and a Ph.D. in biology from the

University of South Carolina.

Ms. Tara Holmberg is a Graduate Research Assistant pursuing an M.S. degree in Marine Science at

the University of Texas at Austin. She performed undergraduate research on coral reefs and

associated organisms of Cozumel, Mexico and the effect of large scale disturbance on the coral reef

ecosystem. Ms. Holmberg received her 13.5. degree from the University of Wisconsin - Superior.
SESSION IG

ACOUSTIC/PRESSURE WAVE EFFECTS ON MARINE MAMMALS

AND SEA TURTLES, PART I

Co-Chairs: Dr. William Lang and Ms. Colleen Benner

Date: December 10, 1998

Presentation Author/Affiliation

Acoustic/Pressure Wave Effects on Marine

Mammals and Sea Turtles: Introduction

An Overview of Use of Explosives by the

G.O.M. Offshore Industry

Advances in Deepwater, High Resolution

Seismic Survey Methods

Cetaceans and Seismic Exploration in the

Gulf of Mexico

Dr. William Lang

Minerals Management Service

Gulf of Mexico OCS Region

Dr. David Leidel

Halliburton Energy Service

Dr. Jack Caldwell

Geco-Prakia, Houston

Dr. Jeffrey C. Norris

Dr. William E. Evans

Ms. Shannon Rankin

Marine Acoustics Lab

Center for Bioacoustics

Texas A&M University, Galveston

353

Marine Mammals and Seismic: The London Dr. Mark L Tasker

Workshop Joint Nature Conservation Committee

Scotland

Office of Naval Research Concerns and Dr. Robert C. Gisiner

Research Initiatives for Acoustic/Explosives Office of Naval Research

Effects Arlington, Virginia

The MMS Pacific OCS Region High-Energy Dr. Mark O.Pierson

Seismic Survey Minerals Management Service

Pacific OCS Region

NMFS Acoustic Criteria Workshop and Dr. Roger Gentry

Related Activities NMFS, Office of Protected Resources

Document Not Submitted
ACOUSTICIPRESSURE WAVE EFFECTS ON MARINE MAMMALS AND

SEA TURTLES: INTRODUCTION

Dr. William Lang

Minerals Management Service

Gulf of Mexico OCS Region

Historically "effects" of offshore oil and gas operations on the environment were mostly associated

with water quality and chemical pollutants. Oil spills, of course, represent the major concern along

with drilling discharges and other potential chemical releases and platform runoff. This session

addresses another potential source of environmental effects - those fromunderwater pressure waves.

In a sense, rather than chemical pollution, we are dealing with energy pollution.

In simplistic terms, we are dealing with a range of events from very high energy, supersonic "blast

waves" resulting from underwater explosions to anthropogenic noise barely detectable above natural

ambient noise levels in the ocean. Similarly, the range of potential effects may be physical

destruction of tissues and death to subtle behavioral responses to either loud or novel sounds. This

session will focus on two offshore industry activities that are of particular concern in regards to

pressure wave effects: 1) Offshore structure removals and 2) Seismic exploration.

In the past, both activities involved use of underwater explosives. Today, the air gun or similar

devices has replaced explosives in all but some shallow water situations for the marine seismic

industry. However, despite efforts to develop nonexplosive technologies, explosive removal

techniques remain a significant method to remove decommissioned offshore structures (Pulsipher

1997). Fish kills are an obvious effect of underwater demolitions. While certainly not desired, in

view of harvesting and by-catch mortalities already inflicted on fish populations, the legal response

to this effect has been one of tolerance or compensation. The situation is quite differentfor marine

mammals and sea turtles given protection under the Marine Mammal Protection Act and/or the

Endangered Species Act. These Acts have compelled the MMS and, in turn, offshore operators to

define acceptable limits on explosiveweights and operating procedures and to initiate a monitoring

program operated by the National Marine Fisheries Service.

Potential death or injury from a blast wave is an obvious concern, but the effects of loud and/or

disturbing sounds is rapidly elevating as perhaps a belated recognized but significant marine

environmental effect. Particularly for marine mammals, loss of hearing or masked communications

can ultimately lead to dire consequences. Sounds sources that scare fish away or disrupt feeding

behavior can lead to resource conflicts between offshore operators and fishermen. Specific for the

oil and gas industry, recent debates on renewing petroleum exploration on the Canadian Georges

Bank has resulted in a series of studies and environmental analyses. One environmental assessment

was devoted entirely to seismic exploration (Davis et al. 1998) and a preliminary report on

environmental impacts by the Canadian Department of Fisheries and Oceans (Boudreau 1998)

discusses seismic effects on a level equal to operational discharges and oil spills.

355
356

As the perception of potential harm from noise pollution intensifies and more information on

biological effects of pressure waves increase, the technology for offshore removals and seismic

exploration is also rapidly changing. Today's session has been assembled to give the audience and

Proceedings reader an overview of explosive removal and seismic technology, information

coordination, regulatory concerns, and biological effects of underwater pressure waves. The MMS

is quite pleased that speakers from industry, academics, research institutions and other agencies have

provided their time to contribute to this session. The Service both appreciates and thanks them for

their effort.

REFERENCES

Boudreau, P. R. (ed.), 1998. The Possible Environmental Impacts of Exploratory Activities on

Georges Bank Aquatic Resources. Canadian Stock Assessment Secretariat Research Docwnent

98/170, 106 pp.

Davis, R. A., Thomson, D. H. and Malme, C. I., 1998. Environmental Assessment of Seismic

Exploration on the Scotian Shelf LGL Limited for submission to CanadalNova Scotia Offshore

Petroleum Board, Halifax, NS, 181 pp. + appendices.

Pulsipher, A. (ed.), 1997. Proceedings: Anlnternational Workshop on Offshore Lease Abandonment

and Platform Disposal: Technology, Regulation, and Environmental Effects, Louisiana State

University Center for Energy Studies! MMS Contract 14-35-0001-30794, 172 pp. + appendices.

AN OVERVIEW OF USE OF EXPLOSIVES BY

THE G.O.M. OFFSHORE INDUSTRY

Dr. David Leidel

Halliburton Energy Service

SUMMARY

The use of energetic materials has been an integral part of oil/gas exploration and production for

many decades and will continue in the foreseeable future.

The use of energetic systems at or near the surface of a welihead or on a platform is driven by

safety risks to personnel; i.e., divers

reliability issues with alternate methods

lack of alternate methods

emergency operations may require expedient and rapid deployment

cost/rig time
357

The use of energetic devices in open water, near the water surface, or at shallow depths of burial

beneath the midline requires consideration of the vulnerability of

swimmers or divers

fish, bottom dwellers, marine reptiles and marine mammals

nearby active oil, gas or water pipelines

nearby vessels or other floating or fixed structures

submarine cables (power or communication)

submerged instrumentation such as hydrophones ortransponders

BACKGROUND OF UNDERWATER EXPLOSION RESEARCH

Serious study began in 1942 to enable the Allies to develop weapon systems to defeat the U-boat and

protect the fleet from submarine attack in a two-ocean war. Early theoretical work was done by John

Kirkwood, Stuart Brinkley, and Hans Bethe (Cornell University), for O.S.R.D. Reports were

published from 1942 to 1945, overseen by George Kistiakowsky. Parallel work was performed in

the United Kingdom by Geoffrey Taylor. "Underwater Explosions" by Robert Cole, the classic text

on the subject, was published by Princeton University in 1948. Cole's study was based on

Kirkwood's earlier work with thorough description of scaling laws. The study, later published by

Dover Publications, is now out of print.

PHYSICS OF THE UNDERWATER EXPLOSION

The detonation of a chemical high explosive underwaterresults in a shock wave propagating outward

from the source of the explosion as well as an initially oscillating bubble containing the products of

detonation which, at later time, rises to the surface. Other results include

seismic effects in the vicinity of or below the seabed, (acoustic energy transmitted through

the seabed)

gas flumes and surface waves at the water surface from shallow explosions

airborne shocks from energy delivered to the atmosphere

possible "aflerburning" of fuel-rich explosives for deliberate enhancement of the blast effects

The Initial Underwater Shock Wave

By definition, a shock wave is a sharp discontinuity in pressure, particle velocity, internal energy,

density, temperature, or entropy of the medium in which the shock propagates. The relationship

between the material properties in front of and behind the shock (Table 1G.l) are governed by the

shock jump relations:

Conservation of Mass p0 U p (U - u)

Conservation of Momentum (P - P0) p0 Uu

Conservation of Energy Pu = '/ p0 Uu2 + p0 U (E - E0)
358

Table 1G. 1. The relationship between the material properties in front of and behind the shock.

The previous three equations containing the five parameters U, u, P, p, and B comprise the Hugoniot

Equation. An additional equation termed the equation of state or constitutive relation is required to

calculate the other four. The equation of state characterizes the material in which the shock is

propagating. While the E.O.S. for many pure materials exist, only limited EO.S. data exist for

geologic materials.

The shape of the initial shock from an underwater explosion may be approximated as a decaying

exponential function of the following form (Figure 1G. 1):

p+ = p e-t/O ') max Definitions

Peak Pressure, (Pmax), represents the maximumpositive magnitude at the initial shock rise

Time Constant, (®), is the time for shock to decay to 1/c of peak pressure magnitude,

(e 2.71828)

Specific Impulse, (Is), represents the area under the pressure-time curve as

10 = fP(t)dt - The upper limit on integration is difficult to assess due to the extended tailoff

of a shock pulse, but 6.7 0 is used in some literature

Energy Flux Density, (Er.) means the energy flux across a unit area of an arbitrary fixed

surface normal to the direction of shock propagation.

COMPUTATIONAL /EXPERJMENTAL METHODS

Subtasks include the following:

Characterize the initial shock: peak pressure, time constant, and specific impulse

Behind Ahead

U uoo

P U P

p PG T T0

E E0
359

Figure 1G.1. Turtle shot #1.

Understand shock propagation effects: seabed burial, effect of nearby structures, effects of

charge shape and explosive type, multiple charges, near-surface effects

Understand shock loading effects on structure of organism

Computational Methods

Semi-empirical algebraic shock scaling equations for shock estimation and approximate

closed-form solution for structural response

Langrangian finite-element method

Eulerian finite-difference method

Semi-Empirical Methods

Semi-empirical algebraic models of shock wave and approximate closed form solutions for structural

response are available for very simple geometries such as elastic or elastic-plastic clamped plates,

shells, and membranes only. Very limited data and incomplete equations are available for charges

buried beneath the seabed. Non-spherical charge geometries are very limited in treatment as are

effects of nearby reflective surfaces and refractive effects. Although semi-empirical methods can

produce considerable error compared to actual measured values, these methods allow analyses to be

conducted quickly and conveniently, without expensive computer facilities or expensive and

specialized software (analyses can be performed on a programmable hand calculator).

Sunimaiy of Semi-Empirical Shock Equations for Underwater Explosions

Equations for Shock Wave Scaling: (after Cole and Faux)

I. Shock Scaling for Spherical TNT charge in open water:

TUR1 Si-D7 1 i/.+ L1 WMP S 3 35 FT RJTA7. 723-1013

#1 Fi( 201 PS

GE 3P = 031E I5.T-5

DELAY SET 7.0 HS

100 //DIV

50 5/DI\
360

W weight of explosive (ibm)

R = distance from blast to receiver (ft)

rn peak shock pressure (psi)

specific impulse (psi-s)

P (2.16E+04)(W"3/R)1'3

'0 = 1 .46Wh/3(WU'3!R)o89

II. Shock Scaling for Cylindrical charge of Comp. C-4 at a seabed burial depth of 7.5 feet:

(8.51E+03)(W"3!R)'18

'0 = 0.93 1W113 (W"3/R)111

Langrangian Finite-Element Method

This method uses the Langrangian model for material elements; i.e., each material element is

"tagged" and its displacement, strains, loads, and stresses observed as time progressesin analyzing

the dynamic response from a transient load or loads. Also used are the JWL equation of state for HE

(an equation of state for water) and a model for nearby surfaces. The structure is modeled using

quadrilateral material elements; the computational scheme uses a formulation for handling nonlinear,

elastic-plastic structural response. A fluid-structure interface model must be used to handle the decoupling of the water from the structural surface, and some form of "hourglassing" control is

required to maintain mathematical stability in the solution.

A model is also required for soils and geologic materials. The codes are expensive, and the model

requires technical staff knowledgeable in the physics of underwater explosions and the mechanics

of structural behavior from rapid dynamic loads to run problems. It also requires computational

facilities of at least IBM RISC 6000 or equivalent. Figure 1G.2 shows an example of a Langrangian

computational mesh.

4

Figure 1 G.2. An example of a Langrangian computational mesh.
361

Eulerian Finite -Difference Method

A mesh is constructed in a stationary or moving laboratory coordinate system, and a material model

is constructed overlaying the computational grid. Equations of motion require that material transport

terms be added to track material as it flows through the grid, much as a fixed observer watches fluid

flow in a wind tunnel. The method requires careful mathematical tracking and control of material

diffusion across grid boundaries. It utilizes a JWL equation of state for explosives, libraries of

equation of state models for metals, concrete, rock, water, and soils. Rock and soil are data limited.

The method also requires material failure models or models for porous materials undergoing

crushing.

The advantage of the Eulerian Finite-Difference Method is that there are no problems with an

"hourglassing" grid as in the case ofLangrangian methods. On the other hand, very stiff portions of

structures may require very small time steps to accurately model response requiring large

computational time. Moreover, it requires at least a workstation equivalent to an IBM RISC 6000

and hours of computational time to solve even 2D problems. 3D problemsrequire parallel processing

capability or supercomputers. Figure 1 G.3 shows an example of a Eulerian computational grid.

Eulerian-Langrangian Codes

Some hydrocodes perform cell calculations using the Langrangian form of governing equations,

(conservation equations, equations-of-state and material constitutive models) and then re-map the

distorted mesh onto the original mesh to avoid problems encountered with large deformations. The

mesh distorts to follow the material motion. Conservation of mass is solved trivially since no

material flows across mesh boundaries. Mesh remapping results in material motion through the

mesh; material interfaces are reconstructed. The user may elect to discard materials if not required

for further computation when the computational cycle is completed.

....UIUIUUI .....,..$'u.0 .U..III.IIuuUU

II iRUUUIUUUII

UI ISUUUIUIUUUUIII UI i.s.uiuuU.UUI I. ul ..a...auu..IIU i....u.....UUU UIUUUIUUUUUUU U.UUUUUUUIUU

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Figure 1(3.3. An example of a Eulerian computational grid.
362

ENERGETIC SYSTEMS CONFIGURATIONS USED rN SURFACE OPERATIONS

Lined-Cavity Charges

Explosive cutting systems using the lined-cavity (shaped charge) effect:

outside circular cutters

inside circular cutters

articulated or collapsible circular cutters

These systems utilize straight or circular segments of linear-shaped charge typically of 900, 1,000,

1,200, 1,400, 2,000, or 3,200 grainlft explosive load in a copper sheath contained in a water-tight

housing to sever structural members.

The water depth limitation for such systems is restricted by the hydrostatic collapse pressure rating

of the subsea housing. Designs have been tested to 18,000 feet water depth, and operations

performed to 5,200 feet. Liner-shaped charge cutters larger than 3,200 grain!ft maybe manufactured

to special order from fabricated housings and cast Composition B.

The use of lined-cavity (shaped charge) devices is the most effectivemethod of metal cutting per unit

weight of explosive since the cut is achieved not be blast effects but by the directed impact of a

hypervelocity metal jet into the material to be severed.

The limitations on applications of lined-cavity charges may be a difficulty in charge emplacement

while maintaining the correct standoff, very thick target materials, or difficulty with access to the

section to be cut. However, these charges can be divers emplaced, ROV emplaced or lowered and

remotely deployed. The cuts resemble a torch cut.

Bulk Charges

Simple bulk charges generally consist of a right circular cylindrical housing containing a cashable

solid or liquid explosive. They can be lowered into the member to be cut or diver emplaned. They

are usually initiated at one end. Simple bulk shots, unless well tamped, are relatively inefficient in

cutting capability. They use relatively large amounts of energetic materials for the size of the

member to be cut, and cuts are not clean but often flared and ragged. Bulk charges are relatively

inexpensive to fabricate by any vendor with melt-casting capability unless liquid explosives are

employed. Liquids can be mixed on location and transported as flammable liquids and not as

explosives.

Collision Charges

These consist of bulk charges with a system that initiates the charge simultaneously at opposite ends

by EBWs or by a special detonating cord initiator train. Collision charges improve the effectiveness

of a bulk charge by using a strong combined shock from opposite ends ofthe charge to focus the
363

cutting effect on a single plane. These charges are often used in liquid explosive welihead severing.

Multiple strings of surface conductors from 11-inch diameter to 30-inch diameter cemented together,

have routinely been severed with 27 pounds net explosive weight of sensitized nitromethane. The

cost is not much higher than simple bulk charges.

Ring, Focused, and Specialty Charges

These charges utilize some fomi of wave shaping, place explosives in direct contact with the

material to be cut, or are deliberately configured to produce tensile fractures in a target at a specific

location. These are specialized explosive charge configurations that do not utilize the lined-cavity

effect, but are shaped more nearly to optimize the cutting effectiveness over simple bulk energetic

systems. These charges are more effective than bulk charges in cutting effectiveness. The problem

with these charges is that their designs are generally proprietary, with their originators and their

configurations covered by patent protection, trade secret protection, or license agreements. Thus,

they are inaccessible as to design details or free use.

SUMMARY OF THE IS SUES

Shock propagation from buried charges and non-spherical charges is not well documented;

little data exist. A set of scaling laws needs to be developed.

Shock propagation near seabed or water surface requires additional study. We need to

develop guidelines for understanding the effects on shock front.

With attenuation systems, air curtains are usually effective in reducing peak pressure,

although they are not as effective on reducing specific impulse.

Explosive systems using minimal explosive weight should be encouraged without

unnecessary design or operational restrictions.

Lethal distances for marine life are difficult to assess; they are highly statistical in nature and

affected by species, orientation to the blast, body weight, and depth of submergence.

Considerable data is required for k estimates.

David Leidel graduated from Drexel University with a Bachelor of Science degree in mechanical

engineering, a Master of Science degree in applied mechanics, and a Doctor of Philosophy degree,

also in applied mechanics. He served in the U.S. Army Combat Engineers in a Special Weapons

Unit. He was employed by BET Defense Systems Company, Inc. as the chief engineer on a tn-service

weapons system prime contact. He worked for Halliburton Energy Service or its subsidiaries for a

total of thirteen years in support of their oilfield products and services, their defense and aerospace

products and their marine services projects. He as authored a number of papers inballistics, energetic

materials, and their applications. He is currently employed by Halliburton Energy Service's

Explosive Products Center as a Principal Engineer.
364

ADVANCES IN DEEPWATER, HIGH RESOLUTION SEISMIC SURVEY METHODS

Dr. Jack Caldwell

Geco-Prakia, Houston

rNTR0DUCTION

This paper provides a brief overview of some of the continued improvements and recent advances

in the acquisition and use of deepwater 3D seismic data. Length constrains the topics to be covered

in this talk to (1) the fact that more and more in-sea equipment is being towed behind purpose-built

and purpose-modified seismic vessels, (2) the development of techniques and equipment that allows

for the simultaneous acquisition of multiple purpose 3D surveys using a single vessel, (3) the rebirth

of the marine vibrator, (4) the potential to better manage oil and gas reservoirs through the use of

repeat 3D seismic surveys (popularly known as 4D seismic), and (5) the high interest in using modeconverted shear wave data in the marine setting, and the increasing variety of marine seismic

acquisition geometries. Emphasis is placed on topics 4 and 5, since they have potentially huge

economic effects with regard to optimizing production from oil and gas fields.

MORE IN-SEA EQUIPMENT

Improvements in vessel technology as well as in towing systems, recording systems, safety systems,

etc., ensure that the seismic industry will continue to increase the amount of in-sea equipment for

the acquisition of 3D seismic surveys (Figure 1G.4). Spreads of up to 1,200 meters or greater and

streamer lengths of up to 12 km will be seen in 1998, deliverable by some contractors with a single

Figure 1 G.4. The seismic industry will continue to increase the amount of in-sea equipment for the

acquisition of 3D seismic surveys with spreads of up to 1,200 meters or greater and

streamer lengths of up to 12 km.
365

Figure 1G.5. The industry can configure the equipment to accomplish two objectives at once.

vessel, and deliverable by other contractors with up to three vessels. The acquisition footprint

associated with a single traverse of a seismic vessel will increase in area over the next couple of

years, and the deep water tracts provide the open water areas where operations ofthis type are most

cost-effective.

MULTIPLE PURPOSE 3D

In addition to putting longer, wider configurations together, the industry can also configure the

equipment to accomplish two objectives at once, as the multi-3D concept has already demonstrated

in the Gulf of Mexico (Figure 1G.5). In this technique, a high resolution site survey is acquired

simultaneously with a conventional, long offset, deep imaging, explorationldevelopment 3D seismic

survey. The rectangular blocks drawn in Figure 1 G.5 indicate the different subsurface image areas

generated by the two different spread geometries, one composed of smaller bins yielding higher

resolution data, and one composed of larger bins yielding conventional 3D resolution. Operationally,

this technique requires some special expertise, as well as the novel use of some fairly standard

equipment. Note the dual source and unequal streamerseparations and streamer lengths employed.

MARINE VIBRATOR

The marine vibrator (illustrated in Figure 1 G.6) idea is not new, having been experimented with

sporadically for the last 15 - 20 years. It appears that the vibratoris ready as a viable technology and

that the industry maybe ready to support it commercially in some specific applications. The primary

attractiveness for the marine vibrator is in its potential to provide higher resolution data than airguns

currently deliver. This is accomplished because the vibrator output signal is very stable and
366

Figure 1G.6. The marine vibrator.

repeatable (Figure 10.7), and because it has a wide, programmable bandwidththe signal can be

tailored to the particular target of interest. If you look closely at Figure 10.7, you can see a variability

in the details of the peaks and troughs of the five traces associated with five firings of a single airgun.

In comparison, note the much greater similarity among the five traces associated with five sweeps

of a vibrator. This illustrates the improved stability and repeatability of the vibrator over the airgun.

While airgun arrays today have greater productivity than vibrators, an array of vibrators may be a

more environmentally friendly source than an array of airguns, due to the lower peak output power

levels of the vibrator.

Single

Airgun Vibrator

, ) r

:- . p- -r

.r r

Figure 1 G.7. The vibrator output signal is very stable and repeatable..
367

Figure 1G.8. The idea of water pushing out oil, or water flowing in behind oil is shown here. Oil

is medium gray, water is black.

SEISMIC TIME-LAPSE MONITORiNG (STLM) OR 4D SEISMIC

In cartoon fashion, the idea of water pushing out oil, or water flowing in behind oil (oil is medium

gray, water is black), is shown in Figure 1G.8, with three different times in the life of the reservoir

portrayed. If we could accurately picture the movement of fluids in a reservoir, then we could use

that information to drill additional wells to drain the bypassed areas, or otherwise better manage our

reservoirs. It has been shown in a few published studies that seismic holds much promise in actually

being able to monitor the movement offluids, when used in conjunction with all other data available

(well log, geologic, core, production, etc.). The basic concept of 3D seismic time-lapse monitoring

is illustrated through the use of synthetic data in Figure 1 G.9: in a perfect world, the difference

between seismic data acquired before a field starts production (the Base survey), and seismic data

acquired after a field has undergone some production (the Monitor survey) will be zero everywhere

Figure 1 G.9. The basic concept of3D seismic time-lapse monitoring is illustrated here through the

use of synthetic data.

Time I Time 2 Time 3
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North Sea Field Fluid Distribution Maps Derived From Seismic Attributes

1985 1995

Oil L Gas Water Non-Reservoir

Figure 1G. 10. A North Sea field example of seismic attributes used to map the fluid distribution in

a reservoir under production.

except where the production of oil andlor gas from a reservoir causes a change in the seismic

response (this "differeneing" between data sets yields the "difference" data set). in reality, it has been

determined, for at least some situations, that some attribute(s) of the seismic data will change as a

result of the movement of the fluids, and that by mapping the change(s) in that (those) seismic

attributes, we will be able to infer the movement of the fluids. In Figure 1G.9, the change is in the

amplitude of the seismic event in the middle of the section.

Figure 1G. 10 shows a real world, North Sea, field example where seismic attributes were used to

map the fluid distribution in a reservoir under production. 3D seismic surveys were shot in 1985 and

1995, although the survey shot in 1985 was not shot with time-lapse monitoring in mind. Both data

sets were reprocessed so as to maximize the consistency in the two data sets.

Fourteen (14) seismic attributes were used to achieve the fluid characterization illustrated here.

Although there are numerous places where there are differences in the depicted fluids, the circled

areas show where perhaps the largest changes in the reservoir have occurred in the intervening time

between the two surveys, indicating places where water has replaced oil. Subsequent drilling has

confirmed the correctness of this picture.

The repeatability of one seismic survey to the next is probably the ma] or question the industry has

with respect to STLM. The following list of statements sum up the situation:

Monitor Surveys Must Look Forward and Backward

Newer Surveys Must Take Advantage of Advancements

Newer Surveys Will Be Bastardized to Compare to Older Surveys

TLM Objectives May Be Quantitative and/or Qualitative

Acquisition and Processing Will Affect Repeatability
369

The fourth statement in this list may require a bit of explanation: if the information to be derived

from a STLM project is quantitative, then more than likely, the repeatability will have to be greater

than if the objectives are qualitative. So acceptable repeatability will be related to the desired

objectives of the STLM.

The maj or potential culprits that may affect repeatability, outside of the reservoir changes themselves

(which we wish to see), include the seismic source, the elements of the seismic acquisition system,

the processing system, the weather, and the structures and facilities associated with the producing

oil field:

Is the source itself repeatable? Is its coupling repeatable? Does the source occupy exactly the

same positions in a later survey as it did in an earlier survey (location)? Do we assign to the

source the proper location (positioning)?

Is the receiver itself repeatable? Is its coupling repeatable? Does the receiver occupy exactly

the same positions in a later survey as it did in an earlier survey (location)? Do we assign to

the receiver the proper location (positioning)?

Was the same recording system used in all surveys to be compared? Are the system

responses the same from survey to survey? Were the acquisition parameters (filter settings,

etc.) set in the system the same way for all surveys?

Were weather conditions the same for all surveys, and were they done at the same time of

year? Was wind/precipitation noise the same for all surveys? Was the sea state the same, or

were wave actionlcurrents much worse for one survey than for another? Was the ground wet,

frozen, ploughed, snow-covered. etc., for all surveys?

Are there facilities present now that were not there for earlier surveys and are the same

facilities running the same way as they were for earlier surveys?

To do quantitative STLM, we have to be able to address many of these questions. As we move from

quantitative STLM to qualitative STLM, the importance of repeatability diminishes, but certainly

does not completely go away.

Partly to address some of the repeatability issues, and partly to acquire higher quality andlor more

complete seismic data, the industry is beginning to use cables either temporarily or permanently

placed on the seafloor, or trenched down into it, and vertical arrays of cables containing many

sensors. The reasons for burying cables are (1) to improve repeatability from survey to survey by

ensuring that the receivers are in exactly the same position for each survey, (2) to ensure higher

quality data because the sensors are in a quieter environment on the seafloor than they are when

being towed near the sea surface, (3) to reduce sensitivity to weather, and (4) to reduce overall cost

when doing numerous repeat surveys (see Figure 1G. 16).

Figure 1G. 11 depicts an array of vertical cables and the trenching of a cable into the seafloor. Cables

laid temporarily on the seafloor, as well as vertical cables, provide true 3D seismic, equivalent to

land 3D, in which full and complete azimuth and offset distribution can be achieved, unlike marine

towed streamer 3D in which the azimuth distributions are quite limited due to the swath style of

shooting (the sources are essentially in-line with the streamer receivers).
370

Figure 1G. 11. A depiction of an array of vertical cables and the trenching of a cable into the

seafloor.

MARINE 4-COMPONENT SEISMOLOGY

Another application makes use of either sensor-filled cables or individual sensor packages which are

placed in direct contact with the seafloor is that of 4-component seismic. The four components are

a hydrophone, a vertical geophone, and two horizontal geophones oriented perpendicular to each

other. All four are included at each receiver station location.

Although they have been in use only for the last 18 months so their track record is brief, the second

generation seabed cables (the first generation of seabed cables being those commonly known as

ocean bottom cables - OBC) routinely deliver data which are higher quality than conventional towed

streamer data (see Figure 1G. 12) for several reasons: higher fold, less smear, broader bandwidth, the

absence of towing and weather-related noise, and the ability to combine the vertical geophone output

with the hydrophone output (combining these outputs results in the removal of much downgoing

multiple energy). Figure 1G. 12 is a data comparison indicating the improved resolution and greater

continuity in events delivered by the seabed cable Systems.

The fact that these cables deliver better data than towed streamers notwithstanding, the reason for

going to the hardship and expense of deploying such seabed systems is to record a type of wave not
371

Hydrophone Data from Vertical Geophone Data

0 10 20 29 39 49 59 68 78 88 98 107 117 Frequency(H

0 10 20 29 39 49 89 88 78 88 98 107 117

F req u en cy (Hz

Figure 10.12. A data comparison indicating the improved resolution and greater continuity in

events delivered by the seabed cable systems.

recordable by streamers: the shear (5-) wave. Conventional towed streamer marine systems only

record compressional (P-) waves. When a P-wave passes through a rock, its behavior is affected by

both the matrix of the rock (the solid part) and the pore spaces of the rock (that portion filled with

liquids and/or gases). To a first approximation, when an S-wave passes through a rock, its behavior

is affected by only the matrix of the rock. Two other important properties of S-waves are that they

travel at roughly half the speed of P-waves, and they can not exist in fluids (hence the necessity of

placing the recording sensors on the seafloor).

The recording of both of these wave types makes it possible to infer much more information about

the rocks in the subsurface and the fluids they contain, and it is the hope of acquiring this additional

information has caused the industry's recent strong and active interest in recording both P-waves and

S-waves. There are several applications of this technology apply equally well in both the onshore and

offshore environment:

Improved lithology (mineralogy) prediction

Improved pore fluid prediction

Better SIN in areas of low P-wave impedance contrast or high P-wave attenuation

Calibration for AVO (amplitude versus offset) studies

Towed Streamer from Seabed Cable
372

Azimuthal anisotropy (the variation of seismic properties with horizontal direction)

Another parameter for seismic reservoir monitoring (4D seismic)

There are other applications listed below that are primarily relevant to the offshore situation:

Imaging within and beneath gas-invaded zones, shale diapirs, mud volcanoes

Imaging base of salt, volcanics

Illuminating P-wave shadow zones beneath salt bodies, particularly those with tops and/or

bases that show significant topography

Deep water multiple removal

More cost-effective when compared to the cost of offshore wells.

Figure 1G. 13 is an example of imaging beneath gas using S-wave energy. It was this particular

example presented in 1994 (Berg, E., Svenning, B., and Martin, J. 1994) that kick-started the interest

in marine multicomponent seismology leading to the multicomponent campaign of about a dozen

tests in the North Sea during the Fall of 1996. This figure shows the P-wave data (the PP section,

which means P-wave downgoing energy and P-wave upgoing energy) being obliterated in the area

of the gas chimney, whereas the PS section (P-wave downgoing energy and S-wave upgoing energy)

provides a relatively clear picture beneath the gas. This particular application of 4C seismic has been

Figure 1G.13. An example of imaging beneath gas using S-wave energy.
Figure 1G.14. P-wave and S-wave velocity imaging beneath salt bodies.

successful in more than a dozen cases since 1996. The other application with about the same number

of successes is that of diagnosing the lithology and/or the fluids filling the pore spaces of a reservoir

rock. Both of these applications are very important in field development work and reservoir

management, so the interest in marine 4C seismology is quite high.

An application not seriously tested in the extensive North Sea activity in 1996 and 1997 is that of

imaging beneath salt bodies. The interest in subsalt is very high in the Gulf of Mexico, but it has

tailed off some with the relatively poor results to date of using seismic imaging to obtain a clear

picture of the structure and stratigraphy beneath salt. It is thought that 4C seismic might provide a

breakthrough, and a survey to test that application was completed in January 1998. The processing

results, not available yet, are eagerly awaited.

Because salt has much higher P-wave and S-wave velocities than the sediments above and below it,

each type of wave is strongly refracted at the salt boundaries, and significant mode-conversion occurs

(see Ogilvie, Jeff S. and Purnell, Guy W. 1996). It is believed that large amounts of S-wave energy

are obscuring the P-wave events beneath the salt. If the S-wave energy is recorded, then either it can

be removed, or it can be used to obtain an image from beneath the salt body. Additionally, as Figure

1G. 14 illustrates, the refraction of one type of wave due to the roughness of the salt surface will

create uneven illumination of reflectors beneath the salt. This uneven illumination results in zones

where a particular wave type will be focused or defocused. The shadow zones so created to one type

of wave are likely to be bright zones to the other type of energy. The use of both types of energy will

thus yield a more complete picture of the geometry of the reflectors beneath salt.

373
374

CABLE or

NODE ARRAY

2D SEISMIC LINE

SOURCE VESSEL

:RECORDING VESSEL

:D SEISMIC GRID

(Can shoot parallel or

perpendicular to

receiver lines)

Figure 1G. 15. An illustration of how a 4-component seismic operation might be laid out.

Figure 1G. 15 illustrates how a 4-component seismic operation might be laid out. A side-scan sonar

survey is run prior to placing the cable on the seafloor to ensure that there is nothing on the seafloor

which can damage the acquisition system, and that there is nothing on the seafloor which the

acquisition system can damage. Depending on the length of the cable, and the conditions on the

seafloor, the cable is either dragged into or draped in position. For 2D work, the source vessel shoots

along the line of a single seabed cable. For 3D work, generally two or more receiver cables are laid

out parallel to each other, and the source vessel shoots several lines overlying the area covered by

the seabed cables. These source lines may be shot parallel to the seabed cables or perpendicular to

them, and the orientation chosen depends on the specific requirements and economics of the

particular survey. One thing to keep in mind about these seabed cable surveys is that if a cable is

dragged on the seafloor, particularly in deeper water areas, then the permitting process will probably

take a longer lead time than commonly required for towed streamer surveys.

Finally, the issue of cost of seabed cable surveys should be mentioned. Figure 1G. 16 summarizes

the present situation in a generic way. Retrievable 4C surveys ("A") cost more than their towed

streamer counterparts ("B" & "E" endpoints), but the cost differential will diminish as the technology

matures. For seismic-time-lapse-monitoring, permanent installation approaches will be more

expensive, in a cumulative sense, for a small number of repeat surveys, but as the number of repeats

reaches a certain level (which will depend on the specific situation, but which seems to be around

10-15), then the total cost will be less than that of a series of conventional surveys.

SUMMARY

This paper has attempted to provide a brief overview of some of the continued improvements and

recent advances being made in the acquisition and use of deepwater 3D seismic data. A constant
# of 3D Surveys

A Retrieveable 4C

B = High Density Towed Marine

C = Permanent 4C

D Permanent 2C

E = Towed Marine

Figure 1G.16. A summary representation of the present cost of seabed cable surveys.

stream of new developments has been ongoing for some time, and it does not look to abate soon.

Conventional towed streamer 3D surveys will continue to be done more efficiently and to deliver

higher data quality. The marine vibrator may shortly be a source in demand for high resolution

surveys and when the environmental conditions dictate it. Time-lapse seismic monitoring, and 4-

component seismic will become important technologies delivered by the seismic contractors for

improved reservoir characterization and management.

REFERENCES

Berg, E., Svenning, B., and Martin, J. 1994. "SUMIC - a new strategic tool for exploration and

reservoir mapping." 56th Annual EAEG Meeting, Vienna.

Ogilvie, Jeff S. and Purnell, Guy W. 1996. "Effects of salt-related mode conversions on subsalt

prospecting", Geophysics 61.

375

Jack Caldwell received a bachelor's degree in mathematics from Davidson College (1971), and a

Ph.D. in geophysics (earthquake seismology and tectonophysics) from Cornell University (1978).

He immediately entered the oil industry as a Research Geophysicist at Texaco's research lab in

Houston where he worked on the overall problem of extracting lithologic information from seismic

data. From 1980 until 1987, Jack held various positions in various locations in research and

exploration in Marathon Oil Company. Hejoined Schiumberger Wireline in 1987, and moved over

to sister company Geco-Prakla in 1992, and currently is Manager, Reservoir Solutions, North and
376

South America, a position he has held since January 1998. The common thread running through most

of his assignments is that he has been involved in developing, introducing, or marketing new

technologies oriented toward extracting lithologic information from seismic data. He has been

involved in some of the discussions that took place between 1996 and 1998 in California with regard

to the HESS (High Energy Seismic Source) workshop and recommendations.

CETACEANS AND SEISMIC EXPLORATION IN THE GULF OF MEXICO

Dr. Jeffrey C. Norris

Dr. William E Evans

Ms. Shannon Rakin

Marine Acoustics Lab

Center for Bioacoustics

Texas A&M University, Galveston

The Gulf of Mexico is almost precisely the size of Alaska, not large for a marine habitat, yet it is the

site of the major oil source in the U.S. outside of Alaska. Not withstanding this, there is no body of

water on earth with a larger diversity of dolphins fourteen of them. This number does not include

other toothed whales such as the sperm whale or the little known beaked whales. Nor does it include

baleen whales such as Bryde's or humpback whales. Twenty-four cetacean species are found here.

Only two of these species are found in shallow water: the well-known bottlenose dolphin and the

Atlantic spotted dolphin. All others are pelagic.

Into this pelagic environment has recently come increased hydrocarbon exploration and production.

Noise from these activities is in addition to heavy shipping and fishing activities. As a first step in

determining the impact on cetaceans of offshore oil activities in the Gulf of Mexico, Texas A&M

University and the National Marine Fisheries Service have been conducting visual and acoustic

surveys since 1992 to describe cetacean distribution, abundance, and ecology. The first stage of these

investigations was GulfCet I, completed in 1996. Both visual and acoustic means were used for

detecting and estimating cetacean numbers. In the northwestern and central Gulf the visual survey

estimated there to be 18,584 (95%CI=l0,268-35,43l) dolphins, while the acoustic survey estimated

36,760 (30,835-43,821) dolphins The visual survey estimate for sperm whales was 313 (63-582),

while the acoustic survey estimate was 316 (265-377). GulfCet II is only now finishing, and

describes cetacean habitats in the central and eastern Gulf of Mexico.

Three aspects of the cetacean community bear on the effects of seismic exploration in the Gulf: a

large and diverse dolphin community, a large and stable sperm whale population, and very few

baleen whales. The dolphins are the largest component to the cetacean community. The animals most

likely sensitive to low frequencies, the baleen whales, appear in small numbers, though mostly in the

eastern gulf where oil exploration is greatest. There appears to be site fidelity among at least some

of the sperm whales, including an area of intense oil industry activity near the mouth of the
377

Mississippi River. This can be taken to indicate that sperm whales continue to use areas of heavy

seismic exploration. It remains, however, unclear whether this site fidelity is a product of low

sensitivity to the noise or a high motivation to remain in the area.

In the 17,000 km where we recorded signals in the Gulf of Mexico, we recorded many forms of

signals that could impact marine mammals. Signals can adversely effect animals by physically

injuring their hearing, causing them to leave important habitats, or masking their own

communication and food finding signals. The form of the signal therefore has an impact on whether

it will affect an animal. For example, a loud pulsed explosion may deafen an animal, whereas a

continuous signal, rain or shrieking bearings on poorly maintained vessels, for example, may result

in the animal's not hearing conspecifics calling or interfere with reception of their sonar signals.

Seismic signals are thought to be strictly low frequency signals, with energies below 1 kHz.

However, we have recorded loud pulsed signals associated with seismic exploration with center

frequencies at 2.5 kHz, with little energy below 1 kHz. These signals are similar in frequency to

sperm whale clicks, and assuming that the whale can hear its own vocalizations, are entirely audible

to the whale. Additionally, other signals such as array locators are also used2 at higher frequencies

(up to 60 kllz). Lastly, the U.S. Navy is considering a series of ship shock trials in the eastern Gulf,

which result in the demolition of thousands of pounds of high explosives.

Beyond simple descriptions of cetacean distribution and abundance, we have begun preliminary

investigations into the impacts on marine mammals of oil exploration. Most importantly we have

found that in the north central and eastern Gulf cetaceans are regularly exposed to seismic signals,

where seismic signals were audible during 34% of the acoustic censusing effort. In thewestern Gulf

this figure is smaller, where these signals were apparent 10% of the time. Controlling for different

hydrographic regions, there was no significant difference in the cetacean sighting frequency for five

acoustic zones which differed in signal-to-noise as a result of seismics. Further, for each

hydrographic region, the observed cetacean distribution associated with seismic sounds does not

significantly differ from that expected by chance. This study, however, does not present any

information regarding smaller scale behavioral impacts.

In explaining the possible responses to seismic signals, it is necessary to understand both how and

why cetaceans react. It is likely that the results noted to date are due to both cetacean hearing and the

seismic signal's frequency and temporal characteristics. We know the auditory thresholds of a few

dolphin species, but little about either sperm whale or baleen whale hearing. However, because of

their low frequency vocalizations and auditory morphology, it is thought that baleen whales have

good low frequency hearing. We suggest that because of their large size and use of relatively low

frequency pulsing, sperm whales also have good low frequency hearing. It is likely that dolphins can

hear the higher components of seismic pulses, though the thresholds are relatively poor at those low

frequencies. Additionally, pulse configuration may effect how seismic signals influence some

cetaceans. Both dolphins and sperm whales produce high amplitude transient pulses. Like most

animals, they have mechanisms to protect their hearing against loud signals. Speculatively, if the rise

time of a pulse is slower than their own signals, it is likely that pulsing cetaceans are particularly well

suited to protect their hearing against loud pulses. There would still be a limit beyond which their

hearing could still be damaged by sufficiently loud transients, but this levelmay be higher than for
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animals, such as baleen whales, that do not produce transients. Designing seismic signals relative

to cetacean pulses may reduce their impact on some cetaceans. Lastly, some signals used in seismic

exploration may mimic some signals used by sperm whales.

MARINE MAMMALS AND SEISMIC: THE LONDON WORKSHOP

Dr. Mark L Tasker

Joint Nature Conservation Committee

Scotland

INTRODUCTION

There has been much recent controversy in the United Kingdom on the effects of seismic exploration

on cetaceans. An increase in sperm whale strandings in the North Sea has been attributed by some

to an increase in seismic surveys in deeper water to the north and west of Scotland. The leading

cetacean conservation organization in UK issued a tape of seismic noise with the clear message that

UK's cetacean population was imperiled by this activity.

At a more official level, the United Kingdom is party to the Agreement on the Conservation of Small

Cetaceans in the Baltic and North Seas (ASCOBANS). This Agreement was concluded under the

auspices of the UN's Convention on Migratory Species and is legally binding on its parties. One of

the objectives of this Agreement is to "work towards. . .the prevention of. . .significant disturbance,

especially of an acoustic nature." As a result of this Agreement, the Joint Nature Conservation

Committee, with others, drew up a set of guidelines for the seismic industry in 1994. These

guidelines contained some practical approaches that were thought would reduce disturbance and

minimize the risk of physical damage to cetaceans. These guidelines were attached as mandatory

conditions on all new licenses issued by the UK government for hydrocarbon exploration. They were

not universally acclaimed: non-governmental organizations felt that they did not go far enough, while

industry felt they were too onerous in the absence of proven effects.

The guidelines were revised after one year in operation to clarifi them, with a commitment to keep

them under review in the light of experience and research findings. In late 1997, industry approached

the Joint Nature Conservation Committee with an offer to sponsor a workshop to examine the whole

issue of seismic and marine mammals. There was still controversy around the issue and it was felt

a fully open workshop would shed light on issues and remove some of the heat. A steering

committee was sought which would involve industry (both hydrocarbons and seismic contractors),

governmental advisors, non-governmental organizations and academics. In the end, NGO

participation on the steering committee was limited.
THE WORKSHOP

The steering committee decided to split the workshop into five inter-related topics and commission

a paper on each topic to generate discussion in a structured fashion. These topics were:

Marine seismic overview

Physics of sound in water

Biology of marine mammals

Seismic and marine mammal interaction

Mitigation of potential effects

These topics focused where necessary on the northeast Atlantic and on features relevant to the

interaction between seismic and marine mammals. The first three topics were as far as possible based

on fact, while some speculation and suggestion were encouraged also in the reviews of the last two

topics to engender discussion. Authors were selected to as far as possible be known experts in each

subject, and co-authorship was encouraged to incorporate a range of opinion. At the meeting,

sessions were organized around each topic, followed by breakout groups and conclusion sessions.

A lively poster session added much information to the proceedings.

MARINE SEISMIC OVERVIEW

The paper described how seismic surveys attempt to map sub-surface geological structures. The

move from 2D surveys to 3D surveys has required closer line spacing, but this has been offset by the

ability to tow more cables behind each vessel. The amount of sound required per unit area of sea has

nevertheless increased. The current standard air-gun array was described and other possible sound

sources discussed. Some information on the geographic changes in areas of interest in the northeast

Atlantic were presented. To understand this issue better, the workshop concluded that

more measurements of the broad band spectrum of airgun sources were required. Industry

is usually only interested in the lowest frequency sounds, whereas cetaceans can hear and

react to higher frequencies.

a critical evaluation of alternative energy sources would be useful in order to determine if any

of these were "cleaner" from the point of view of unwanted sound.

a historical database of seismic activity would be useful in indicating if any broad-scale

changes in cetacean distribution had occurred as a result of changes in seismic surveying

PHYSICS OF SOUND IN WATER

The propagation of sound through water theoretically follows a set of fundamental principles.

However, in real life, these principles interact in a complex fashion to produce results that are often

not predictable. Modeling of the propagation of seismic sounds is thus difficult without in Situ

measurements at the time that testing is to take place. This is particularly the case in relatively

variable shelf seas. The literature on this topic has also become confused by a plethora of

measurement techniques and units. The usual unit for measuring output level, the decibel, is a

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relative unit, and confusion over the reference level used also abounds. The review considered also

other sources of marine sound, pointing out that levels of sound produced at some frequencies by

shipping exceed those produced at those frequencies by seismic testing. The workshop concluded

that better understanding in this area would

help define a propagation model that would enable "safe" limits to be set on the proximity

of marine mammals to seismic sources,

better define possible impacts when making environmental assessments are made, and

help in studies of the reactions of marine mammals to sound

This could be achieved by further modeling of known situations and by makingnew measurements

with a dedicated system. These approaches could usefully be combined to examine variability in

propagation and specific situations. A further review of anthropogenic noises and studies priorto

seismic exploration would provide useful information on the range at which seismic testing would

be masked, and on the relative levels between seismic noise and background noise.

BIOLOGY OF MARINE MAMMALS

Knowledge of the biology of cetaceans and seals in the northeast Atlantic was reviewed. Relevant

biological features include the following:

the numbers and migration of species occurring in the region,

their breeding cycle (are there particularly sensitive times ofyear when any potential effects

should be particularly avoided?),

their feeding regime (surface feeders vs. deep divers),

their ability to hear or sense sound and

their reaction to disturbance

The deep waters to the north and west of Britain are known from a variety of studies, not least

sightings from seismic survey vessels, to be important (in aNE Atlantic context) for the larger whale

species and for deep diving species such as the beaked whales. A certain amount is known about

breeding cycle, both from records made during the whaling era and from sightings since then. Rather

little is known about ability to hear and sense sound, or precisely how cetaceans use and process that

sound. There have been a few observational studies of disturbance reactions (see next section).

The meeting agreed that the disparate sources of information on the distribution of marine mammals

in NW European waters should be bought together as far as possible to enable a "gap" analysis. A

library of audio grams should be compiled, using the little available information and by creating a

"rapid-reaction team" in NW Europe to collect information on stranded or trapped mammals. To

form this team, experience from the United States could usefully be acquired and a formal protocol

developed. There was discussion of the need to study and record "natural" behaviors of marine

mammals, so that any changes in behavior might be more easily identified.
SEISMIC AND MARINE MAMMAL INTERACTION

The range of potential direct impact of seismic sound on marine mammals could run from severe

injury to body tissue through permanent or temporary reductions in auditory sensitivity (threshold

shifts). In addition, disturbance could result in behavioral alteration or sound could mask

communication or other uses of sound. Indirectly, food stocks might be affected, leading to a

reduction in foraging opportunities. Over a long period, such effects may accumulate to cause other

problems. There have been few direct studies worldwide of these effects. John Richardson presented

a summary of one of the best of these studies: on bowhead whales off Alaska. On a related topic, it

was noted that disturbance might also lead to a reduction of economic opportunity in the form of

whale-watching.

The methods by which effects might be detected were discussed. Population dynamics might be

examined, but results would be available oniy in the long-term, be expensive and difficult to obtain

and likely to lack in statistical power. Studies of body condition would be difficult, especially in

ascribing cause and effect. Behavioral studies appear to offer the best way forward with visual and

acoustic observations from seismic "chase" boats and from other platforms of opportunity likely to

be useful and comparatively cheap. The definition of "significant effect" presents some difficulty.

If "critical habitat" can be defined for relevant cetacean species, perhaps by the use of population

gradients, then the evasion range could be compared with the spatial scale of the critical region to

give an indication of the likely significance of any disturbance. Studies on physical and hearing

damage presently under way in the United States would be informative.

MITIGATION OF POTENTIAL EFFECTS

Current potential mitigation measures include

seasonal and geographic limitations on surveys,

soft-start (ramp-up) procedures,

safety-zones around noise sources,

use of minimal source power compatible with imaging subsurface targets

The degree to which these are implemented varies world-wide. In the United States, legally-binding

legislation is used. The UK's guidelines have been used in several other areas worldwide. The

various mitigation measures are limited by knowledge. The application of proper limitations on

surveys relies on sufficient accurate information on marine mammal distribution. The effectiveness

of soft-start has not been critically evaluated. In the United States, safety zones have been defined

as the distance at which sound levels are above 180 dB (re 1 tPa (rms)), although even these

distances have proved controversial. Ill the UK, a blanket 500m is recommended in the guidelines.

The difficulty of seeing marine maninials within and outside the safety zone can be addressed with

the use of acoustic monitoring devices or by dedicated ship or aerial survey.

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The workshop suggested that in addition to the above, the industry should

strive to design sources that minimize the output outside the usable bandwidth,

review the effectiveness of soft-start

better define safety zones

develop a more transparent administrative procedure to re-assure third parties,

develop strategic EIA for seismic operations to help guide regional activities

CONCLUSION AND THE FUTURE

The workshop was successful in reviewing current knowledge and procedure and in identifying areas

where we are presently deficient in information. In terms of wider involvement in the issue, most

participants went away happy. It is likely that a further workshop will be convened in two or three

years.

ACKNOWLEDGMENTS

The "seismic and marine mammal" workshop was organized by Joe Karwatowski, Chris Walker,

Ingebret Gausland, Dave Thompson, Jonathan Gordon, Anne Walls, George Chisholm, Jim Gulland

and me. The workshop was sponsored by 29 hydrocarbon or geophysical companies. The authors

of the main topics were Jim Gulland, Chris Walker, Ingebret Gausland, Dave Thompson, Peter

Evans, Jonathan Gordon, Doug Gillespie, John Potter, Alexandris Frantzis, Mark Simmonds, Rene

Swift, Pat Birnie, Jay Wagner, Vance Langford and Mark Pierson. I thank them and all others who

attended for making the workshop a success.

Mark Tasker has worked on the conservation of offshore animals for the UK government since 1979.

In early years this was primarily as a researcher on the marine distribution of seabirds, but since 1987

Mark has progressively moved into information and advice provision. Such advice is targeted

primarily at offshore industry and fisheries managers. Mark was a member of the organizing

committee of a workshop on seismic and marine mammals held in London in June 1998.
OFFICE OF NAVAL RESEARCH CONCERNS AND RESEARCH INITIATIVES

FOR ACOUSTIC/EXPLOSIVES EFFECTS

Dr. Robert C. Gisiner

Office of Naval Research

Arlington, Virginia

INTRODUCTION

The U.S. Navy is deeply committed to operating in an environmentally safe manner (see Navy

website at http://206. 5. 146.1 OO/n45/branch/n454/). To foster better understanding of the potential

effects from impulse sound, and to develop the means to better assess and mitigate such effects, the

Office of Naval Research has initiated research to shed light on this issue. It is our hope that the

information thus obtained will not only facilitate the U.S. Navy's requirements to meet its

commitment to environmentally safe operation, but will be of use to other federal, state and local

agencies, as well as to relevant industry and other nongovemment parties, and to the general public.

The ONR program is one of scientific data-gathering and dissemination. While it is typically

considered desirable that legal guidelines and policy rely heavily on science-based information, it

is important to remember that the two processes are independent, and that one should not draw

premature conclusions from this presentation about implications for Navy or national policy,

guidelines or regulations. In some cases I will be describing experimental designs that have not yet

produced data. In other cases I will describe work so recently completed that there has not been

sufficient time for full peer review and incorporation into an accepted body of knowledge upon

which to base legal and policy decisions. In all the projects I will be discussing, the concept,

execution, interpretation, and dissemination of the work is considered to be the property of the

researcher. For example, the determination of temporary threshold shift effects (TTS) from impulse

sound is a scientifically feasible project, and one that is currently being undertaken by investigators

under ONR sponsorship. However, the ultimate use of such information in policy or guidelines is

still very unclear and hinges on discussions as far-reaching as the relationship between permanent

and temporary hearing loss, the legal definition of "harassment" under the Marine Mammal

Protection Act, and the ability of organisms to cope with decreased auditory function in both the

short and long term. It would be beyond the scope of this discussion (and the author's expertise) to

speculate on the significance of such information for Navy or national policy and procedures.

BACKGROUND ON THE OFFICE OF NAVAL RESEARCH AND ITS ROLE

The Office of Naval Research was created in 1946 to continue the successful interaction between

universities, government and industry that emerged during World War II. ONR was the first formal,

large-scale government program to foster basic research outside the government and was a model

for other federal research funding agencies, such as the National Science Foundation (Vest 1996).

The role of the current ONR remains much the same, over 50 years later. Success, for ONR

programs, is as much about metrics of academic achievement such as peer-reviewed publications

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and Nobel prizes as it is about delivering new science and technology products to the Navy. As you

will see, the ONR research program into the effects of impulsive sound on marine organismstakes

advantage of ONR scientific leadership in such areas as underwater acoustics and marine mammal

biology to provide cutting edge science that is not only useful to the Navy but contributes to a

generally accessible knowledge base with a wide range of potential uses. The work involves

expertise and facilities at universities, Navy research laboratories, National Marine Fisheries Service

and the Army. All work from the program is unclassified and will be published in scientificjournals

or other publicly accessible sources under academic peer review.

BACKGROUND ON IMPULSE SOUND AND ITS EFFECTS

Impulse sound is generally defined as sound with an irregular and sharp waveform (rapid pressure

oscillations), as opposed to sounds produced by regular oscillation of some mechanical device or

material which produces a sinusoidal pattern of pressure change (see Figure 1G. 17 for some

examples). Some sources of impulse sound, explosives and airguns for example, show obvious

differences from a tonal sound source like a loudspeaker or rotary machinery noise (e.g. see

Richardson et al. 1995). But many other sources of sound may not be so easy to categorize, such as

sonars which are capable of producing a loud tonal signal with very rapid onset. A recent meeting

of technical experts convened by National Marine Fisheries Service was unable to arrive at a

satisfactory "simple" definition for separating impulse or transient sounds from tonal or continuous

sounds, so no definition will be attempted in this presentation. What is important is that clearly

impulsive and clearly tonal sounds be compared to look for differences in effects on hearing,

comparable to the differences observed for airborne impulse and tonal sounds. In air, impulse sounds

tend to produce more variable effects than tonal sounds, in part because it is difficult to measure the

exact characteristics of an impulse such as peak pressure or frequency composition, and in part

because features of biological response such as structural failures, protective reflexes and effects of

orientation can result in widely varying outcomes for different individuals exposed to the same

impulsive sound (Kryter 1985).

Also, the sound energy from impulse sources comes to resemble a tonal or continuous sound at

increasing range due to frequency spreading and multi-path transmission between source and

receiver. If one were to imagine this effect visually, the waveform would appear to become smoothed

or "mushy" and spread out in time. Acoustically, an impulse would be perceived as a "pop" or

"click" near the source and would sound like a more prolonged rumble at greater distance due to the

time-delayed arrival of sound energy along several paths, and the tendency of lower frequencies to

propagate further than high frequencies (Urick 1975). Thus the same sound heard at one mile and

six miles might not only differ in loudness, but in features of frequency structure and duration as

well.

The major differences of interest between impulse and tonal sounds are

1. many impulse sound sources produce greater peak over- or under-pressures than tonal

sources. For example, a loud explosion may produce peak pressures 100 or more times
Near $OurCS At tant ins Impuise from an exploston(from Urick, 1975) From pure tones to complex sounds Impuke from a dolphin (from Au, 

iLF '.41 This is £ SPEECH IAVEFQW 

A complex tonal sound (sp

Figure 1G. 17. Examples of impulse and tonal sounds.
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greater than the loudest tonal sources (e.g. 270-280 dB re 1 .tPa for a large explosion versus

220-230 dB re 1 tPa for a sonar).

2. the rise time to peak pressure, or the time between peak over- and under-pressure may be so

short (microseconds) that physical structures cannot flex over the course of the pressure

change, and they break or are displaced. The result can be damage to hearing or other

structures at sound pressure levels that might produce little or no effect from a tonal source.

These accelerative effects are greatest where there is a difference in the medium transmitting the

sound with a resulting change in sound speed. Soft-bodied organisms likejellyfish or sea cucumbers

may be unaffected by even very loud sounds because the pressure wave passes through their bodies

as through seawater. Organisms that contain gas-filled spaces, e.g. fish with swim bladders or turtles

and mammals with lungs, will experience mechanical movement at the interface between two media

such as air and water, resulting in rapid accelerative movement and tearing of tissues or blood

leakage in lungs, middle ears, or digestive tract in proximity to gas pockets. In some cases the

acceleration of denser tissues such as middle ear bones or ribs may result in damage to those

structures or the tissues around them (Yelverton 1981; Young 1991).

These effects should not be conftised with damage from the shock wave, which is a mechanical force

generated by an explosion or by water displacement by expansion of a compressed air bubble from

an airgun. In close proximity to an impulsive source, an organism may be damaged by the shock

wave as it physically accelerates both the medium and the organism, but in a dense viscous medium

like water the shock wave does not travel very far, usually only tens or hundreds of meters for the

vast majority of impulse sources.

RATIONALE FOR THE ONR PROGRAM

Lethal and injurious effects from shock waves and sound overpressure or energy flux are well

documented and will not be discussed in detail (see Yelverton 1981; Young 1991; Ketten 1995).

Larger animals are likely to withstand greater peak pressures. Keep in mind that these are received

values, and source levels might be much higher, depending on the range from the source.

At the other end of the spectrum are noninjurious behavioral responses to impulse sounds.

Hypothetically, any sound that can be heard could elicit a behavioral reaction. In reality, the

probability of eliciting a reaction, and the type of reaction elicited, can vary greatly with species,

individual experience, alertness or the nature of the sound and the circumstances under which it

occurs. Because of the tremendous variability of behavioral response, it will undoubtedly be very

difficult to develop metrics for "harassing" sound or some other boundary between biologically

significant or consequential noninjurious sound levels and inconsequential but audible sound levels.

ONR and other Navy activities expect to generate data on behavioral reactions in the course of

monitoring and mitigation efforts, but it will probably be some time before sufficient data

accumulate to suggest any general predictive relationships between impulse events and behavioral

reactions.
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In this context ONR has focused on quantifiable physiological or percept-based effects of impulse

sound that can be experimentally induced, replicated and verified in statistically meaningful ways,

but which bridge the region between injurious effects and more variable, less predictable behavioral

responses. The two studies we have selected for finding are briefly described below.

TEMPORARY THRESHOLD SHIFT (TTS)

This study is being carried out under the leadership of Dr. Sam Ridgway at the Space and Naval

Warfare Systems Center (S SC) in San Diego, using a sound source provided by the Naval Surface

Warfare Center (NSWC) in Carderock, Maryland. The TTS protocol developed by Ridgway and his

colleagues at SSC has been used to generate data on the levels of pure tones that induce a small ( six

decibel) quickly recovered hearing loss (Ridgway et al. 1997). Using the impulse sound simulator

developed by NSWC Dr. Ridgway will employ the same protocol to determine the onset of brief

temporary threshold shift to a simulated signal replicating an impulse event at some range from the

source. The NSWC device uses multiple tonal transducers to produce a plane wave that replicates

an impulse sound through the constructive and destructive interference of the different individual

signals produced at each transducer. The simulator cannot replicate the sharp microsecond duration

waveform found at or near a source, but it can replicate the more spread out signal found at ranges

of thousands of meters from the source. At that range, the signal is still only a few tenths of a second

long at most and, therefore, still much shorter than the tonal signals which usually last a second or

longer. Ridgway' s experimental protocol also allows for testing of other impulse sources such as

airguns and sparkers and for testing the scaling relationship of TTS to multiple impulse exposures.

The onset of temporary threshold shift to short (one second) tonal signals at frequencies between 400

Hz and 70 kHz have been on the order of 190-200 dB, and we anticipate that responses to shorter

duration impulse events will be at similar signal strengths (Figure 1G. 18), but a question that is best

resolved by the empirical data. However, we still do not know if there will be greater variability in

the onset levels from test to test than we are seeing for tonal signals or if the broadband impulse

events will exhibit stronger effects on certain hearing frequencies due to the mechanical properties

of the ear or for other reasons. In terrestrial mammals, TTS to impulse sounds tends to be more

variable than to tonal sounds, probably due to irregular reactions by ear protective mechanisms and

effects of orientation. Terrestrial mammals also tend to show greater TTS effects at higher

frequencies than the stimulus, probably due to the shape of the inner ear.

Ridgway employs an operantly conditioned, food-reinforced testing procedure that tends to produce

the greatest and most consistent indication of hearing sensitivity. The effects of methodology on

results are being assessed by independent parallel efforts undertaken by Ron Schusterman of the

University of California at Santa Cruz and Paul Nachtigall and Whitlow Au at the University of

Hawaii. Three species of marine mammal are being tested at SSC; California sea lions (Zalophus

calfornianus), bottlenose dolphins (Tursiops truncatus), and beluga or white whales

(Deiphinapteras leucas). The experiment begins with a pre-test hearing check. Then, after a variable

delay, the 'inducing" sound stimulus is played and another hearing check is administered (Figure

1G.19). When hearing is checked after the inducing sound and a decrement of six decibels is

obtained (the minimum statistically significant difference in this particular design), a temporary
[: 4I+er.erl I I P 1 .d eh

3190 10/63 20/63 20/73 20/76 75/70 

Figure 1G.1 8. Sample results of hearing sensitivity testing on marine mammals.
Figure 1G.19. Diagram of the TTS testing enclosure. At listening station 1, the dolphin got an Si signal from pro

proceeded to listening station 2 for hearing threshold testing. Projector B delivered the S2 tones, aemitted the white noise that served as level background. Monitoring hydrophone D was used to r

signals for precise determination of acoustic amplitude at the dolphin's lowerjaw. Monitoring hy

recorded the dolphin whistles emitted by the animal when it heard an S2 tone.
390

threshold shift is said to have occurred, and the level and duration of the inducing signal is noted.

For the short duration signals used thus far (most are one second long), recovery to pre-test levels

generally occurs within 15-30 minutes of the TTS event Animals must return to full pre-test levels

before they are allowed to do another TTS test.

TTS is of interest for two reasons. First, it bears some relationship to Permanent Threshold Shift

(PTS). Though the causal relationship is not clear, it appears that repeated TTS events can lead to

PTS, and onset of TTS bears a fairly consistent relationship to onset of PTS (Kryter 1985; Ward

1991). Since it is undesirable to deliberately induce PTS to determine the actual onset of permanent

hearing damage, testing for TTS at least gives us a "ballpark" number for reducing the likelihood

ofPTS. Second, TTS means that an individual is temporarily deprived of a specific degree of hearing

acuity and for a specific duration. During that time, the individual has a reduced ability to receive

environmental sensing and communicative acoustic information. The quantification of TTS effects

thus enables one to make more reliable and precise risk assessments about the effects of a given

sound source that has the potential to cause TTS.

MEASUREMENT OF MACRO AND MICRO SCALE

DAMAGE FROM IMPULSE EVENTS

Since it is impossible to test for damage effects in live, free-ranging animals, this experiment makes

use of specimen materials collected by the National Marine Fisheries Service Stranding Program.

Microscopic structures such as the cilia on inner ear hair cells retain their structural mechanical

properties for a considerable period post mortem and can be used to construct predictive mechanical

models of the damage likely to be induced in live animals by a given impulse event, even if the effect

is restricted to such microscopic effects as damage to hair cells, with no other obvious injury.

Dr. Darlene Ketten of Woods Hole Oceanographic Institution and the Harvard Medical School will

use special techniques that she developed for high resolution x-ray computed tomographic scanning

(CT scan) to create 3-D images of intact ears in specimens provided by the NMFS Stranding

Program (see Ketten 1997). The specimens will be CT scanned before and after exposure to a

controlled, measured impulse event, and then standard histological techniques will be used to further

assess the nature and extent of damage induced by a given impulse event. Figure 1 G.20 provides

a schematic illustration of the sequence of experimental procedures. Sound output from explosives

scales with charge size (Kibblewhite & Denham 1970), so small charges in test pools are sufficient

to establish predictive relationships for larger at-sea impulse events without the risk of uncontrolled

inadvertent exposures of marine life during testing. Likewise, effects scale with the size and

robustness of the ear structures (Ketten 1995), so tests will be conducted on small specimens (harbor

porpoises) and tissue blocks containing the ear structures and surrounding supportive tissues for

larger species like baleen whales.

In addition to impulse waveforms from explosives, other impulse waveforms, such as those from airguns, may be tested. Eventually the energetic correlates of damage can be merged with measured

dimension, mass and resilience of auditory structures to create a predictive model of damage (Figure

10.21), such as exists for human in-air auditory damage from guns and explosions (Price & Kaib
National Marine Fisheries Service Stranding Network Specimen I' '.___. modelingtesting screening Histologica

microsco

Figure 1 G.20. A schematic illustration of the sequence of experimental procedures.
Diffracci sound fieldRcf Air Earcanal Plug Rp( Concha t---- LI L2 L3 'ength Butie [Midd'e Ear Ear&um conductive part Ldm Cdc Rdc tNt Eardnim Lever Malteo- independent and area Incudal part ratio joint In CU S Li Cmi Cis T Rmi IRs Ves

Annular Vo

ligament Stapes,,_, 

Ls Cal Ral L

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Figure 1 G.21. A predictive model of damage created from the energetic correlates of damage merged with measu

mass and resilience of auditory structures.
393

1996). The Price model is currently used to establish exposure safety standards for the U.S. Army

and NATO for in-air impulsive noise. It should be relatively easy to adapt this model for marine

mammal and human ears underwater to provide a similarly useful predictive model of damage from

underwater impulse events.

CONCLUSION

The experiments led by Ketten and Ridgway should provide a much more detailed and statistically

stronger set of metrics for risk assessment and damage prediction, even for very small damaging

effects. These data can serve as cross-checks to each other and to current predictions based on human

or terrestrial animal models, since the phenomena they measure overlap. Both Ketten and Ridgway' s

data should support predictive math models that can be used to extend their results to impulse

sources of different sizes producing sounds of different frequencies and durations, and the models

should scale in predictable ways for animals of different size.

These experiments, which should be completed within the next two years, are expected to enable us

to establish very definite criteria concerning the potential for injury and temporary performance

losses from impulse sound, ranging from lethal and serious effects to tiny recoverable effects. As

indicated earlier in this paper, the potential for purely behavioral effects is much more difficult to

assess and will probably produce much more variable outcomes that will be difficult to reconcile to

simple models for impact assessment and prediction. At some point, NMFS and the interested

community at large will probably want to make a cost-benefit analysis of the remaining risk after

immediate damaging effects have been clearly defined and mitigated. While it is possible that some

risk may exist from adverse behavioral or cumulative sub-threshold effects, it remains to be seen

whether such effects constitute a significant threat to individual or population survival and wellbeing, and if so what kinds of efforts and what level of support will be required to resolve these

remaining questions.

REFERENCES

Ketten, D. R. 1995. Estimates of blast injury and acoustic trauma zones for marine mammals from

underwater explosions. Pp. 391-407. In Kastelein, R.A., J.A. Thomas and P.E. Nachtigall, eds.,

Sensory Systems ofAquatic Mammals. DeSpil Publishers, Woerden, Netherlands.

Ketten, D.R. 1997. Structure and function in whale ears. Bioacoustics, 8: 103-137.

Kibblewhite, A.C. and R.N. Denham. 1970. Measurements of acoustic energy from underwater

explosions. J. Acoust. Soc. Am., 48: 346-35 1.

Kryter, K.D. 1985. The Effects of Noise on Man. Academic Press, Orlando, FL.

Price, G.R. and J.T. Kalb. 1996. Evaluation of hazard from intense sound with mathematicalmodel

of the human ear. J. Acoust. Soc. Am., 100:2674.
394

Richardson, W.J., C.R. Greene, Jr., C.I. Malme, and D.H. Thomson. 1995. Marine Mammals and

Noise. Academic Press. New York, NY.

Ridgway, S.H., D.A. Carder, R.R. Smith, T. Kamolnick, C.E. Schlundt, and W.R. Elsbeny. 1997.

Behavioral responses and temporary threshold shift in masked hearing threshold of bottlenose

dolphins, Tursiops truncatus, to 1-second tones of 141 to 201 dB re 1 .iPa. Technical Document,

NCCOSC RDT&E DIV D3503, 49620 Beluga Rd., San Diego, CA 92152, June 1997.

Uriek, R.J. 1975. Principles of Underwater Sound for Engineers. McGraw-Hill, New York, NY.

Vest, Charles. 1996. ONR: An academic perspective. In Fifty Years of Excellence in Support of

Naval Science: A symposium in celebration of the fiftieth anniversary of the Office of Naval

Research. National Academy of Sciences, Washington D.C. 22 May 1996.

Ward, W.D. 1991. The role of intermittence in PTS. J. Acoust. Soc. Am., 90: 164-169.

Yelverton, J.T. 1981. Underwater explosion damage risk criteria for fish, birds and mammals. 102nd

meeting of the Acoustical Society of America, Miami Beach FL. 32pp.

Young, G.A. 1991. Concise Methods for Predicting the Effects of Underwater Explosions on Marine

Life. Naval Surface Warfare Center, NAVSWC MP 9 1-220. July, 1991.

Dr. Robert Gisiner is the Marine Mammal Science program officer for the Office of Naval Research.

He manages basic and applied research programs in Effects of Anthropogenic Noise on Marine

Mammals, Biosonar, Biolocomotion, and Diving Physiology. Dr. Gisiner is also a member of the

Steller Sea Lion Recovery Team and the Coastal America Science and Technology Advisory Group.

He received his Ph.D. in Biology from the University of California at Santa Cruz. His research

interests include behavioral ecology, animal cognition, and biosonar.
THE MMS PACIFIC OCS REGION HIGH-ENERGY SEISMIC WORKSHOP

Dr. Mark 0. Pierson

Minerals Management Service

Pacific OCS Region

THE HESS PROCESS

During this decade, several sound-producing projects off the California coast have increased concern

over and public interest in the problems of underwater sound and marine mammals. These have

included the U.S. Navy's plan to ship-shock test new warships using high explosives, Scripps

Institution of Oceanography's ATOC experiment to detect evidence of global warming from changes

in water temperature, an Exxon 3-D seismic survey m the Santa Barbara Channel, and, more

recently, the Navy's low-frequency active sonar project (LFA).

The Exxon survey, conducted in the fall of 1995, was the first seismic survey in Pacific Outer

Continental Shelf (OCS) waters since the late 1 980s. Controversy over this project brought Exxon,

MMS, NMFS, several state, and local agencies, fishermen, and environmental groups to an impasse

over survey procedures and mitigation that was resolved only after several last-minute meetings. This

was a very unsatisfactory process. Consequently, after completion of the Exxon survey MMS's

Pacific OCS Region met in June 1996 with all interested stakeholders and agreed to establish the

High-Energy Seismic Survey (HESS) Team. The purpose of the Team was to develop a standardized

set of acceptable procedures for the review of seismic survey proposals off southern California. The

Team also agreed to discuss the scope of environmental review necessary to conduct future surveys

and possible mitigation measures. The drafted review process and mitigation guidelines were then

to be presented to the Pacific OCS Regional Director for approval.

PURPOSE OF THE WORKSHOP

Given the ongoing scientific controversy over the potential effects of low-frequency sound on marine

mammals, the HESS Team decided to convene a workshop. The purpose of the workshop was to

provide a forum for a scientific expert panel to discuss and provide responses to scientific and

technical questions. This information was intended to assist the Team in developing protocols for

the review of seismic surveys and, in particular, to help develop mitigation measures and to identify

needed studies.

Prior to the workshop, a series of technical questions were drafted by a subcommittee, which

included representatives of MMS, NMFS, industry, the Joint Oil/Fisheries Liaison Office, and

environmental groups. The Team as a whole provided input and reached consensus on the fmal list

of questions.

395
396

The subcommittee also developed a list of possible scientific panel members, which was presented

to the Team for review and approval. The panel convened was first-rate, consisting of distinguished

scientists with expertise in the fields of geophysics, bioacoustics, and marine mammals (Table 1 (i2).

The two-day workshop was held on 12-13 June 1997, at Pepperdine University in Malibu,

California. The workshop was videotaped, and notes were taken by the facilitators and raporteurs.

A written summary of the proceedings and the panel's recommendations was prepared with input

from the panelists. The information presented here was abstracted from the draft final workshop

report.

Table 1G.2. Scientific panel members at the MMS Pacific OCS Region High-Energy Seismic

Workshop, Pepperdine University, Malibu, California, 12-13 June 1997.

John Calambokidis

Cascadia Research Collective

Olympia, Washington

Dr. Daniel P. Costa

University of California, Santa Cruz

Santa Cruz, California

Dr. William T. Ellison

Marine Acoustics, mc,

Middletown, Rhode Island

Dr. Charles R. Greene

Greeneridge Sciences, Inc.

Santa Barbara, California

Dr. Gordon M. Greve

Orion Consultants

Durango, Colorado

Dr. Darlene R. Ketten

Harvard Medical School

Boston, Massachusetts &

Woods Hole Oceanic Research Institute

Woods Hole, Massachusetts

Dr. W. John Richardson

LGL Ltd., Environmental

Research Associates

King City, Ontario, Canada

Dr. Samuel I-I. Ridgway

U.S. Navy NCCOSC

RDTE Division

San Diego, California

Dr. Bernd Wtirsig

Texas A&M University at Galveston

Galveston, Texas
RESULTS OF THE WORKSHOP

The panel was presented with seven major questions, each of which had a number of subparts. The

panel's discussions and responses to each of the questions are summarized below.

1. What are the important factors that influence the generation and propagation of sound ft-Sm

high-energy seismic sources in water in the study area?

The panel concluded that estimating the acoustic field generated by an array of source

elements is complicated, but possible. They agreed upon a conceptual model for describing

the sound source that distinguishes four regions. The panel noted that it was easier to predict

the distance from the source and decibel range for each zone than to predict actual effects.

They felt that, given our current level of understanding of the effects of underwater sound

on marine mammals, improving our knowledge of potential effects at the closer ranges is a

better use of resources than defining the parameters of each zone more precisely.

The four regions identified were:

Very Near Field (within 30 meters). Effects within this range will be dominated by the

single most powerftil source in the array. Exposure in this region could cause tissue

damage and, possibly, acoustic trauma.

Near Field (up to 100 meters). Within this zone, the beam from the array has not yet

formed, and signal strength may have lost up to 30 dB. Exposure may disrupt important

behavioral processes (e.g., feeding, mating).

Close-in Field (100-200 meters). The beam from the array has formed at this distance.

Exposed animals will experience temporary threshold shift (TTS), although the effects

will be primarily behavioral.

Far Field (beyond 200 meters). The signal has spread considerably at this point. While

signal strength is decreasing, the sound may be audible at great distance from the source

(up to 100 km for some species). The actual distance will be a function of the source

spectrum, transmission loss, an animal's hearing sensitivity, and the ambient noise in the

spectrum of interest. At these ranges, a response is still possible.

The panel agreed that the modeling process is more complicated in the far fields, where

ambient noise plays a much greater role and a great deal of on-site data is needed. Water

temperature, bottom topography, and sediment type are also important factors in the far field.

397

2. Under what conditions can modeling be used as a reliable approach for detennining the

propagation characteristics of sound energy from a high-energy airgun array to define, for
398

example, areas for protection of marine mammals? How technically feasible, reliable, and

cost-effective is pre-survey field verification, and when should it be considered?

The panel concluded that, given the quality of currently available models, pre-survey

verification is unnecessary. They recommended that companies conducting seismic surveys

employ a good, site-specific propagation model, developed in advance and incorporating the

best available information on local bottom topography; add a safety buffer; make actual

measurements as early as possible during the survey; and adjust accordingly. They agreed

that such a model would be fairly accurate within a kilometer (but that it would be important

to look at hot spots, i.e., 8 and 16 miles away). These recommendations have been

incorporated into the interim HESS mitigation guidelines.

3. What is known about marine mammal physiology and behavior that would suggest potential

impacts to mammals from introducing high-energy seismic sound into their environment?

What might constitute an unacceptable level of impact?

The panel discussed the range of potential impacts to marine mammals that might result from

the introduction of sound into the marine environment. They identified the following five

categories of impacts:

Physical trauma - includes physiological damage and acoustic trauma.

Biologically relevant impacts - not acute, but disrupt important biological functions, e.g.,

causing animals to leave feeding areas, or disrupting reproductive behavior.

Harassment - it is necessary to differentiate between the legal threshold and a biologically significant threshold. In biological terms, the level at which behavior changes might

be set as the threshold for harassment, but it should be noted that behavioral changes

range across a continuum. NMIFS is continuing this discussion while redrafting their take

regulations under the Marine Mammal Protection Act (MMPA).

Chronic effects - long-term, e.g., adrenaline build-up (stress).

B Infrasound - these are non-auditory physiological effects, including such barely

perceived physiological effects as nausea and dizziness.

The panel members indicated that it is difficult to ascertain when a temporary threshold shift

(TTS) occurs. Also, an animal might not experience discomfort until long after actual

damage has occurred (the "Walkman effect"). Permanent damage can also occur from TTS

over time.

The panel also discussed the importance of motivation, the phenomenon of masking, and the

adequacy of current data on effects. These and subsequent discussions culminated in a series
399

of recommendations for future research, which were presented at the end of the workshop

(see below).

What are appropriate safety zones and zones of influence for an array in the study area,

beyond which impacts, as defined above, decrease to an acceptable level?

Asked to define appropriate safety zones to protect marine mammals, the panel began by

criticizing NMFS' interim acoustic criteria to determine whether marine mammals are being

"taken" under the MMPA. They felt that not enough was known about marine mammal

hearing processes and structures to use these criteria to evaluate marine mammal harassment.

A recent NMFS workshop focused on the problems of take criteria (Gentry, this volume).

However, the panel did conclude that, given what is known from other systems and until

additional information can be obtained, they were "apprehensive" about received levels

above 180 dB re 1 t Pa (rms) with respect to overt behavioral, physiological, and hearing

effects.

A majority of the panel concurred that the 1 80-dB statement should be applied to all marine

mammals. Several panel members suggested adopting a slightly higher level for groups that

have poor low frequency hearing (small odontocetes and pinniped), but his suggestion was

not accepted. The final consensus was to add a second sentence indicating that they were

"aware of the rationale for suspecting that the threshold of hearing or physiological damage

might be higher for some groups of marine mammals," but that "the available data did not

allow any firm conclusion."

To obtain this information, the panel strongly recommended experiments to test overt effects

on the hearing, behavior, and physiology of pinriiped and small cetaceans. They felt it was

less likely that large shales would be exposed to close-range sound, but, considering their

expected greater sensitivity to low-frequency sound and their levels of population endangerment, that there was a need for guidelines on incidental exposure of these whales.

Although discussion of these criteria is continuing, the interim HESS mitigation guidelines

do define safety zones for all marine mammals as the area around the airgun array within

which received levels of sound are at or above 180 d13 re 1 i Pa (rms).

Effects below 180 dB. The panel agreed that studies are needed to determihe the occurrence

and nature of behavioral reactions to sounds at levels below 180 dB re 1 j.i Pa (rms). They

recognized that there might be responses at or near ambient noise levels, but felt that the

most likely response range is above 140 dB re 1 p. Pa (rms). They did stress, however, that

a measurable response does not necessarily signify a biological concern.

What changes in survey operational design might result in reduced impacts?
400

Since animals are always present, the panel felt that seasonally based prohibitions should be

provided for species most sensitive to sound and/or at the highest levels of endangerment.

Because this is not always practical, they recommended that surveys be designed using

criteria based on distance to the most sensitive and/or endangered animals.

The panel prioritized marine mammal species in the southern California study area according

to the following factors: 1) sensitivity to low-frequency airgun sounds, and 2) level of species

or population endangerment. They identified the following three priority levels:

First Priority: blue, humpback, fifi, and gray whale.

Second Priority: sperm whale, elephant seal, other mysticetes.

Third Priority: other odontocetes, other pinnipeds.

Priority species have been taken into consideration in the design of monitoring protocols for

the interim HESS mitigation guidelines.

Since continuous (24-hour) operations would complete a survey as quickly as possible, the

panel agreed that they generally would be preferable to longer, intermittent surveys.

However, continuous surveys require night operations, which involve a trade-off regarding

the ability to visually detect animals vs. the advantages of continuous operation. The panel

concluded that night operations require case-by-case evaluation, considering factors such as

seasonality (hours of daylight, weather, migration patterns), priority of animals of concern,

and economics. The use of continuous operations is an issue that is still unresolved in Team

discus sions of the interim HESS mitigation guidelines format.

The panel stated that, although unproven, ramp-up is a desirable mitigation measure, pending

further research into its effectiveness. Ramp-up is in use worldwide as a mitigation measure

for seismic survey operations and has been incorporated into the interim HESS mitigation

guidelines.

6. What approaches for monitoring or mitigation efforts in the zone of influence are most

effective?

The panel responded to this question by first establishing the following objectives for a

monitoring program: 1) to implement mitigation, 2) to estimate take, and 3) to monitor

species for potential far-field effects.

Shipboard observers. The use of shipboard observers is, along with ramp-up, the mitigation

and monitoring measure most widely employed for seismic surveys. The panel felt that, at

minimum, there should be observers on the seismic vessel, and recommended having

multiple observers on dy at onetime. They felt that observers aboard the scout boat are also

useful, since they can see farther ahead of the seismic vessel.
401

The panel emphasized that, while data collection is important for future planning and

permitting, it is important to distinguish the behavioral observation roles of observers from

their mitigation roles. The interim HESS mitigation guidelines call for observers to be aboard

the seismic vessel during all surveys.

Aerial surveys. The panel considered aerial surveys to be a valuable tool for examining an

area broader than near-field and useful foridentifying concentrations of animals. Pre-survey

aerial surveys may provide infonnation necessary for the implementation of mitigation

measures, such as delaying the start of a seismic survey. Survey information could also be

used to estimate harassment during a seismic survey, although multiple replicates over the

area are necessary to clarify whether such an effect is occurring. The interim HESS

mitigation guidelines call for aerial surveys under some circumstances when high-priority

marine mammal species are known to be present in the survey area.

Passive acoustic monitoring. The panel considered this approach to be worth exploring and

evaluating as a mitigation measure. They felt that, if feasible, detection of animals in the

safety zone by this method should be a criterion for shutdown. Passive acoustic monitoring

is not called for under the interim HESS mitigation guidelines.

7. Are there other approaches for reducing impacts?

Operation at reduced levels. The panel recommended that seismic surveys be conducted at

the minimum sound level practicable.

Bubble curtains. The panel concluded that bubble-curtain physics are theoretically sound,

but that implementation is difficult with current technology.

Acoustic deterrents. The panel felt that pingers and other active acoustic deterrents added

additional noise and did not clearly provide an additional deterrent effect.

Additional mitigation measures. The panel felt that combining passive acoustic arrays with

aerial surveys would maximize knowledge of the marine mammals present in the survey

area, although such a methodology is expensive. They suggested that "enhanced" visual

techniques also be considered.

STUDY RECOMMENDATIONS

Finally, the panel made several recommendations for future research:

Studies on overt hearing, behavioral, and physiological effects relating to sounds at or above

the 1 80-dB + 10 dB level for different species (with focus on pinnipeds and small cetaceans).

Studies on potential effects in the 140-180 dB range.

Studies on the effectiveness of ramp-up procedures.
402

Research into new techniques (e.g., passive acoustic) and their effectiveness as monitoring

tools.

A baseline study to compile information (matrix) on species, animals, distribution,

population status, and sensitivity to sound in California waters.
Meteorology of the Northeastern Gulf of

Mexico

Northeastern Gulf of Mexico Physical

Oceanography Program: Eddy Monitoring

and Remote Sensing

Nearshore Bottom Properties over the

Northeastern Shelves of the Gulf of

Mexico as Observed During Early

May 1998

De Soto Canyon Physical Oceanography

Modeling Currents in Northeastern Gulf

of Mexico: An Evaluation

SESSION IH

PHYSICAL OCEANOGRAPHY SESSION

Co-Chairs: Dr. Alexis Lugo-Fernndez and Dr. Mary Boatman

Date: December 10, 1998

Presentation Author/Affiliation

403

Dr. Mark Hocke

ENVIRON International Corp.

Dr. Frank F. Muller-Karger

Department of Marine Science

University of South Florida

Dr. Fred Vukovich

Science Applications International Corporation

Dr. Robert Leben

Department of Aerospace Engineering Sciences

University of Colorado

Mr. Bisman Nababan

University of South Florida

Dr. Worth D. Nowlin, Jr.

Dr. Ann E. Jochens,

Dr. Matthew K. Howard

Dr. Steven F. DiMarco

Department of Oceanography

Texas A&M University

Dr. Peter Hamilton

Science Applications International Corporation

Raleigh, North Carolina

Dr. Y. Hsueh

Dr. Yury Golubev

Department of Oceanography

Florida State University

Preliminary Report on Coastal Upwelling Dr. Sneed B. Collard

and Mass Mortalities in the Northeastern University of West Florida

Gulf of Mexico During Spring and

Summer 1998
404

Presentation Author/Affiliation

Physical Oceanography/Biological Dr. Harriet Perry

Integration Gulf Coast Research Laboratory

Document Not Submitted Dr. Donald R. Johnson

Naval Reserach Laboratory
METEOROLOGY OF THE NORTHEASTERN GULF OF MEXICO

Dr. Mark Yocke

ENVIRON International Corp.

STUDY TEAM

Prime Contractor: ENVIRON International Corp.

Subcontractors: Sonorna Technology Inc.

Aerovironment Environmental Services

Evans Hamilton Inc.

Consultant: Dr. S.A. Hsu. Louisiana State University

Expert Advisory Group: Dr. Richard McNider, University of Alabama, Huntsville

Dr. Allan Clarke, Florida State University

STUDY OBJECTIVES

Base Effort - Identify and acquire available meteorological data in the Northeastern Gulf of Mexico

region for a two-year period, 1996 and 1997 - Design and populate a relational data base containing all collected data

- Develop an expert computersystem to allow rapid access to the data base, data analysis

products, and air trajectory analyses

Add-on Work - Archive ETA model output for 1996 and 1997

- Add ETA model output to relational data base and expert system

CURRENT STATUS

Completed: Phase 1 Collect and archive 1995-1997

(Year 1) Meteorological data

Phase 2 Analyze data

(Year 2) Develop expert system

In Progress: Phase 3 Acquire ETA model output for 1996 and 1997

(Add-on) Add ETA model output to data archive and expert system

DATA SOURCES

(Table 1H.1 and Figure 1H.1)

National Climatic Data Center (NCDC)

National Data Buoy Center (NDBC)

Breton Island

USGS Center for Coastal Geology

405
406

Table liii. Data inventory in MMS database.

Station ID Station Name Station Type Range of Data

00013858 ELGIN AFB/VALPARAIS Upper Air 95-97

00013861 WAYCROSS/WARE Co. Upper Air 1/95

00013889 Upper Air 95-97

00053813 SLIDELL MUNICIPAL Upper Air 95-97

00093805 TALLAHASSEE RGNL Upper Air 95-97

42001 MID GULF Buoy 95-97

42002 W. GULF Buoy 95-97

42003 E. GULF Buoy 95-9/96

42007 OTP Buoy 95-97

42036 W. TAMPA Buoy 95-97

42039 PENSACOLA Buoy 95-97

42040 MOBILE SOUTH Buoy 95-97

722055 OCALA MIJNI (AWOS) Land Based 95-97

722120 CROSS CITY Land Based 95-6/96

722130 WAYCROSS/CARE CO. Land Based 95-96

722135 ALMA/BACON Land Based 95-97

722140 TALLAHASSEE RGNL Land Based 95-97

722146 GAINESVILLE RGNL Land Based 95-97

722160 ALBANY MUNICIPAL Land Based 95-97

722166 VALDOSTA REGIONAL Land Based 95-97

722210 ELG[N AFB/VALPARAIS Land Based 95-97

722215 CRESTVIEW/BOB SIKES Land Based 95-97

722223 PENSACOLA REGIONAL Land Based 95-97

722225 PENSACOLA NAS Land Based 95-97

722226 WHITING FLD NAS-N Land Based 95-97

722230 MOBILE/BATAES FIELD Land Based 95-97

722235 MOBILE DOWNTOWN Land Based 95-97

722245 PANAMA CITY/BAY CO Land Based 95-97

722246 DUKE FLD/ELGIN AUX Land Based 95-97

722267 TROY MUNICIPAL Land Based 95-97

722268 DOTHAN MUNICIPAL Land Based 95-97

722269 CAIRNS AAF/OZARK Land Based 95-97

722275 ANDALUSIA/OPP ARPT Land Based 95-97

722276 SCHELL AHP Land Based 95

722307 GOLDEN TRI Land Based 95-97

722309 GRANDE ISLE Land Based 9 5-97

722210 NEW ORLEANS INTERNATIONAL AIRPORT Land Based 95-97

722316 NEW ORLEANS NAVAL AIR Land Based 95-97

722348 PINE BELT RGNL AWOS Land Based 9 5-97

747685 GULFPORT-BILOXI Land Based 95-97

747686 KEESLER AFB/BILOXI Land Based 9 5-97

747750 TYNDALL AFB Land Based 95-97

747770 HURLBURT FIELD Land Based 95-97

747810 MOODY AFB/VALDOSTA Land Based 95-97

BURLI SOUTHWEST PASS, LA C-Man 95-97

BUSL1 BULLWINKLE BLOCK 65 C-Man 8/95-10/96

CDRF1 CEDAR KEY, FL C-Man 95-97

CSBF1 CAPE SAN BLAS, FL C-Man 95-97

DPIA1 DAUPHIN ISLAND, AL C-Man 95-97

GDIL1 GRANT) ISLE, LA C-Man 95-97

KTNF I KEATON BEACH, FL C-Man 95-97
32.00 31.00- 30.00- 29.00- 27.00- , C S S S s8 s S S1J B B B S

I I 1 T I 1 1 I 1 -93.00 -92.00 -91.00 -90.00 -89.00 -08.00 -07.00 -86.00 -85.00 -84.00 -83.00 

C: C-Man Site B: Buoy Sfte N: Surface Site ti: tJpperAirSite 

Figure 1 H. 1. Location of MMS Northeast Gulf of Mexico meteorological data sites. 26,00- B B S SS U
408

DATA SEARCH (NO DATA)

Oil companies

Universities

National Weather Service

Government laboratories, agencies, and programs

Private sources

DATABASE STRUCTURE AND DATA ARCHIVING

Database hardware and software

- PC network

- Windows NT (servers)

- Windsow95 (computers) - Microsoft ACCESS

Station information tables - Station ID

- Station name - Station type - Latitude

- Longitude - Elevation - Call letters

Parameter tables

Sfc. winds

Gusts

- Temp. and press. - Precipitation - Visibility - Sky conditions

- Upper air data - Sea sfc. temp.

- Wave data

Spatial interpolation of mean and std. dev. values

Time-series analyses

Data transfer - Internet file transfer protocol (FTP) - Individual user upload and download folders

- User passwordsfor access to individual user upload and download areas - Database status folder (in FTP area)

Database security

- Database on AVES network
- Daily system backups - Off-site copies of daily system backups

DATA HANDLING

Data screening

- Run add data through screening routines to verify accuracy - Criteria for maximum values - Criteria for minimum values - Criteria for rates of change

Data validation

Verify maximum values

Verify minimum values - Verify rates of change that exceed criteria

Make comparisons with NOAA Monthly Weather Summaries

STATISTICAL ANALYSES

Mean and standard deviation of all measured parameters at all stations(Figure 1 H.2) - annual

- by season

- by met-type

Calculate derived parameters

- PBL parameters - Vertical vorticity - Stress, stress curl

- Heat flux

SYNOPTIC WEATHER TYPING

Objective: Classify days by consistent weather types; use classifications for basis to

calculate statistical summaries of data. Surface winds and pressure gradients

are critical variables.

Preliminary review and refinement of classifications

Weather classifications and examples (Figure 1H.3)

REFINEMENT OF CLASSIFICATIONS

Reviewed eight synoptic weather types for New Orleans (Muller et al.)

Performed preliminary classification of 1994 days using 1 2Z (0700 EST) daily weather maps

Refined synoptic types to address NE Gulf surface winds and pressure gradients

Applied refined classification of 1996-1997 12Z daily weather maps to evaluate process

409
10 m/s 32W) 3100 30.00 29.00 HEk!Rrg 2OO / AI t1 28.00 I .90.00 89.0O MMSMet Mean Annual Winds 1995-1996 (rriwi?k \ .'. \ N N N N \ Al ny I \ \ N N \f 4. Doih - \ N N I - - __\_ Tflthaiee - I / -88.00 -8700 Figure 1H.2. MMSMetmeanannualwinds 1995-1996.
411

Figure 1H.3. Representative examples of eight synoptic weather types for New Orleans, Louisiana

(from Muller and Wax 1977).
412

PROJECT ADD-ON--ETA MODEL OUTPUT

Offshore meteorological data sites are widely spaced and limited in number; therefore,

calculations of spatial gradients for wind stress, wind stress curl, and vertical vorticity are

difficult and suspect.

Archival of NWS ETA meteorological model results was proposed to add spatial resolution

afforded by solution of the governing primitive equations:

- NCEP routinely runs the ETA model several times each day for numerical weather

prediction - recently NCAR began archiving ETA model output

- NCAR is also creating an archive of historical ETA model output back to October 1985

The ETA model assimilates large volumes ofobservational data for initialization. Therefore, - initial and analysis fields are relatively faithful to observed conditions

- these can be viewed as interpolation between observation points based solutions of the

governing physics

ETA model output could substantially improve the information available from this NEGOM

study.

ETA MODELADD-ON TASKS

Investigate of available ETA model output products (completed)

Acquire appropriate ETA model outputs for 1996-1997 - 1997 data ordered and received - 1996 data available from NCAR in early 1999

Decompress ETA data files and parse for NEGOM region

Add ETA output to data archive

Extend to expert system to access ETA model output files

NEXT STEPS

Complete acquisition (i.e., 1996) of ETA model output

Develop software to decompress and parse ETA model output for NEGOM domain

Calculate derived parameters from ETA model output

Add NEGOM ETA model output to NEGOM data archive

Extend expert system to include access to ETA model output

Complete conceptual model of regional meteorology and circulations based on observational

data and ETA model output

Final report
413

NORTHEASTERN GULF OF MEXICO PHYSICAL OCEANOGRAPHY PROGRAM:

EDDY MONITORING AND REMOTE SENSING

Dr. Frank E. Muller-Karger

Department of Marine Science

University of South Florida

Dr. Fred Vukovich

Science Applications International Corporation

Dr. Robert Leben

Department of Aerospace Engineering Sciences

University of Colorado

Mr. Bisman Nababan

University of South Florida

INTRODUCTION

The continental shelf off Florida in the northeastern Gulf of Mexico has unique fisheries and

environmental characteristics that could be affected by oil and gas development. There is, however,

a general lack of historical information on the oceanography of the region, and particularly on the

effect that large scale ocean circulation features like the Loop Current and its associated eddies may

have on the oceanography of this shelf region. It is critical to understand the motion of waters within

a region to assess the potential consequences of possible spills derived from oceanic, shelf, and

coastal mining industries. This study is being conducted to help assess the value ofmerged satellite

data and specific oceanographic field data in determining the circulation andbiological productivity

of waters within the NE Gulf of Mexico. The primary objective of this effort centers on collecting,

processing, and merging historical and concurrent infrared, radar-altimetry, and ocean colorsatellite

data as well as selected in situ information like drifting buoy trajectories obtained incollaboration

with other Gulf of Mexico MMS programs.

METHODS

Satellite Data Compilation

We collect and process selected satellite time series data to identify and track major circulation

features in the Gulf of Mexico. Specifically, we developed a set of software tools to generate daily

AVHRR Sea Surface Temperature distribution fields, TOPEX and ERS-1 Radar Altimetiy Sea

Surface Height fields, and Coastal Zone Color Scanner and SeaWiFS ocean color-derived pigment

concentrations. We collect the AVHRR and SeaWiFS data with an antenna installed in St.

Petersburg, FL. We have operated this antenna since late 1993 and are able to cover the Gulf of

Mexico with the AVHRR up to 2-3 times per day and with SeaWiFS at least 1-2 times per day. We
414

have also processed the CZCS data for the Gulf of Mexico (1978-1986) to examine historical

circulation patterns. We are still working with NASA on the calibration and algorithms to be used

with SeaWiFS, as products still do not match field data. The TOPEX and ERS data have been

merged and interpolated at the University of Colorado to render one image per day.

We have collected approximately 3,500 AVHRR images since April 1997 and about 420 SeaWiFS

images since September 1997 (the date of first SeaWiFS data) over the Gulf of Mexico. The

historical CZCS data were processed at USF to show pigment concentration, and then averaged to

derive a series of 92 monthly concentration means. We have also computed monthly mean sea

surface temperatures for the Gulf of Mexico for 1996-1998 (present; data located at

htip://paria. marine. usf edu), and merged the corresponding average sea surface dynamic height with

each of the SST monthly means, in the form of overlayed contours. These data were remapped to

cover only the NEGOM region for purposes of overlaying drifting buoy tracks. All the software to

overlay these various data sets and to analyze the image fields in terms of geophysical values (SST,

pigment, altimetry) were developed in house using the IDL programming environment.

Field Program

We teamed up with Dr. Worth Nowlin and Dr. Douglas Biggs ofTexas A&M University (TAMU)

to participate in MMS-sponsored oceanographic cruises to the NEGOM (Chemical

Oceanography/Hydrography Program). To date we have participated in three NEGOM cruises: May,

July-August, and November 1998. Each cruise provides about 12 days shiptime. The cruises provide

an extensive, high quality hydrography and chemical oceanographic background against which we

collect detailed pbytoplankton pigment and bio-optical observations. This will serve to characterize

regional waters and validate the regional SeaWiFS products that we processed systematically.

We complement the TAMU field measurements with along-track dissolved organic matter (DOM)

fluorescence measurements and total absorption/c-beam attenuation coefficient observations in seven

spectral bands. At specific stations we also measure water-leaving radiance (Lw), downwelling

irradiance (Ed), diffuse attenuation coefficient (K), and PAR (Kpar) measurements using abovewater and in-water instrumentation. These measurements allow an estimate of Remote Sensing

Reflectance (Rrs). At these stations we also obtain water samples for laboratory analyses of the color

of particulate and dissolved material (specific absorption coefficients).

Drifting Buoys

Both Walter Johnson (MMS) and Peter Niiler (Scripps Institute of Oceanography) provided buoy

data for the Big Bend region of Florida. These data cover February 1996 through May 1997. Buoys

were deployed every two weeks for 24 deployments in the Big Bend region over the period above.

A total of about 335 drifters were used in the experiment. We also obtained the monthly mean

averaged velocity vectors derived from the buoy trajectories. We developed a set of software tools

to overlay drifting buoy tracks over the satellite-derived S ST and altimeter maps. We further mapped

and overlayed the monthly-mean velocity vectors on S ST/altimeter merged fields. Currently the
415

mean drifter tracks representing January, February, and March include data from drifters deployed

both in 1996 and 1997.

RESULTS

The AVHRR data provides substantial information on circulation patterns during the winter

(October-May), when temperature gradients are strong.However, during summer (June-September),

AVHRR data for the most part shows uniform sea surface temperature patterns over the NEGOM

(Muller-Karger et al. 1991). The AVHRR can provide some information on the position of the Loop

Current during summers after images are contrast-stretched. Also, significant upwelling events can

be seen during summer along the periphery of the NEGOM, specifically in coasts of the Big Bend

region and in the region off Pinellas and Manatee Counties (near the mouth of Tampa Bay). The

historical ocean color data obtained from the CZCS shows that the pigment concentration patterns

are an effective tool for tracing small scale as well as large scale circulation patterns in the GOM,

pasrticularly during summers. The altimeter data, while providing sampling at roughly 10-day

intervals, provides all-weather sampling. Therefore the combination of AVHRR, TOPEX/ERS, and

CZCS/SeaWiFS is very robust for outlining the position of the Loop Current, eddies, and various

instability waves visible along fronts in the region.

General Circulation in the NEGOM

Upon merging the AVHRR sea surface temperature data with the altimeter fields, we found

extremely good correlation between warm areas and elevated dynamic heights, and cool areas and

low dynamic heights. Low SST and low dynamic sea level indicate a cyclonic circulation, whereas

the high SST and high dynamic sea level indicate anticyclonic circulation. Such features are

particularly pronounced along the Loop Current.

Most individual drifter tracks were very close to the shore (<50 km) where the altimeter data are

questionable. However, farther offshore, both the individual drifter tracks and the monthly-mean

velocities derived from these drifters help in interpreting the direction of flow within specific

features observed in the images. Features in the images are stable enough so that over the period of

several weeks to a month, there is correspondence between what can be observed in the ephemeral

drifter tracks and the time-averaged satellite data.

In January-March, flow immediately to the east ofthe Mississippi delta seems to be erratic or

turbulent, with vectors in adjacent 25-km cells having either northward or southward components.

However, flow in the eastern portion of the NEGOM and over the west Florida shelf is distinctly and

strongly (> 10 m 1) southward (Figure 1H.4). Waters here are much colder (>5 C) than Loop

Current waters. The Loop Current extended about halfway north into the GOM from Yucatan

Straight, and a cyclonic eddy sat between the northern extension of the Loop Current and the

NEGOM shelf. In April 1996, drifter vectors over the shelf reversed, showing a slow (< 10 m 1)

drift to the north. However, along the shelf break of the West Florida shelf proper, current vectors

remained strongly southward. The cyclone north of the LC drifted somewhat to the West in May but
416

Figure 1H.4. Monthly mean Sea Surface Temperature images (Left: March 1996; Right: August

1996). SST is shaded according to the color bar insert. Contours represent altimeterderived sea surface topography rendered for the 1 5th day of each corresponding

month. Contour labels are shown in [cm]. White contours represent high elevations

and black contours represent depressions. Vectors represent monthly-mean velocities

derived from drifter positions within 25x25 km boxes in the NEGOM. Vectors are

colored black if they have a northward component and white if they have a southward

component.

drifted back East over the summer. By August, currents over the shelf aligned themselves to flow

northward at speeds exceeding 10 rn s - In September, currents over the shelf were to the south again

(1 0 rn s1), and an eddy was shed from the Loop Current. The southward flow over the shelf

intensified in October. In November, while southward flow was observed over the shelf, northward

flow was observed along the shelf break. In December 1996, southward flow prevailed over the West

Florida shelf. This general description of flow over the West Florida Shelf agrees very well with

conclusions derived from current meter data (R. Weisberg, USF, pers. comm.).

Anomalous Summer Coastal Upwelling

During winter months (December-April), it is quite usual to observe cold SST near the coasts of the

NEGOM and over the adjacent shelf. In May, SST in these coastal areas tends to be as warm as

waters within the interior of the GUM. In 1998, the AVHRR satellite imagery provided the first

indications of an anomalous coastal upwelling event in the NEGOM in that lasted from about May

through June 1998. In May 1998 we noticed cool SST's (23-24 C) immediately off Cape San Blas,

in a strip that extended along the coast of the Florida panhandle to Mobile Bay. This event was

notable because SST in the interior of the GUM reached extremely high values compared to other

years. We estimated temperatures in the interior of the Gulf reached 28-3 0 C in early July, but in

large portions of the Gulf and in Florida Bay SSTs soared past 30-32 C in June. The colder SST strip
417

grew offshore, and then shrank again over a period of a few days. For example, in early June this

strip reached order of 20-30 km inwidth at temperatures less than 24 C (almost 23 C near the coast).

The width decreased after that, but the strip then grew again toward the second half of June. On June

28/29, warm SST were observed along the coast, but the first week in July cold patches were seen

off Cape San Bias and to the east, and the strip was re-established. On 13 July, the cold waters

seemed to extend offshore well over 50 km south of Cape San Bias, but this cold patch seems to

have receded by 14 July. While we are still unclear as to what SeaWiFS data shows us in this area,

we can definitely see high "pigment concentration" plumes extending south of Cape San Bias and

the coast to the east.

In a 7 July 1998 SeaWiFS picture, we could see the northern boundary of the Loop Current was

located approximately at the latitude of Florida Bay. A counter-clockwise eddy, however, was

located just north of the Loop Current, and a clockwise eddy immediately to the north of this

cyclone. The existence of this cyclone/anticyclone pair was verified in altimeter data.

We propose that this northernmost anticyclonic eddy is the likely cause for the upwelling in the

northeastern Gulf of Mexico. In a SeaWiFS image for the 16 July, the discharge of the Mississippi

River can be seen wrapped around the anticyclone, and was advected away from the delta toward

the southeast, toward the DeSoto Canyon region and further offshore, partially masking the eddies.

We would propose that the major low-02 zones found in the region, however, are associated with

high discharge from the Apalachicola or Mobile Rivers in spring 1998.

By 22 July, the AVJ-IRR data showed that the upwelling bad subsided and coastal waters were as

warm as offshore waters in the NEGOM.

Hurricane Activity

Changes in sea-surface properties associated with hurricanes Earl and George were observed in the

NEGOM using NOAA and SeaWiFS satellite data. In each case, a region low SSTs was detected

which was located, for the most part, to the right of the hurricane's track. The lowest SSTs were

found near or at the shelf break. These features were most likely associated with the intense

upwelling produced by hurricane winds. For Earl, SSTs were as much as 3-4 C lower and for

George, as much as 5-6 C lower than those for the surrounding water. The fact that the lowest SSTs

were located near the shelf break suggested that the shelf slope may have acted to intensify the

upweliing produced by the hurricanes.

SeaWiFS also detected a region with higher pigment concentrations atthe surface immediately south

of the shelf break near the Mississippi Delta region after the passage of Georges. However, the

feature was principally to the left of the hurricane's path and west of the region where the most

intense SST changes were found in the AVHRR data. This feature wasprobably shelf water that was

advected southward into the deep GOM by the hurricane's cyclonic circulation.

For Georges, both the SST and the pigment features drifted to the southwest and decreased in size

over a 19 day period. Over the period of about 19 days, the average speed of the low SST feature
418

(- 18 cm/s) and the high biomass feature (-1 9 cmls) was about the same. The temperature in the cold

lens developed by hurricane George increased by 2.2 C in 3 days reaching a relative steady-state

value of about 25 'C at that time, reflecting the rapid dilution of this feature.

REFERENCES

Muller-Karger, F.E., J.J. Walsh, R.H. Evans, and MJ3. Meyers. 1991. On the seasonal phytoplankton

concentration and sea surface temperature cycles of the Gulf of Mexico as determined by

satellites. Journal of Geophysical Research. 96(C7). 12645-12665.

Frank E. Muller-Karger uses ocean color and infrared satellite imagery to assess physical and

biological variability in the Gulf of Mexico and Caribbean Sea. He is also studying the role of

oceanic waters along continental margins in the global carbon cycle. Dr. Muller-Karger served at

NASA Headquarters as Program Scientist for Ocean Biogeochemistry between 1992 and 1994, and

is a member of NASA Science Teams for various satellitemissions. He is Associate Professor at the

University of South Florida, Department of Marine Science. Dr. Muller-Karger obtained a Ph.D.

from the University of Maryland, an M.S. from the University of Alaska, and a B.S. from the Florida

Jnstitute of Technology.

Fred Vukovich is Chief Scientist for Science ApplicationsInternational Corporation. He has been

involved in oceanographic studies using satellite data forthirty years, focusing primarily on the Gulf

of Mexico (GOM). Dr. Vukovich has studied and developed statistics on the characteristics of the

Loop Current, including eddy shedding periods, the behavior of cold-core eddies on the boundary

of the Loop Current, the intrusion of Loop Current water onto the West Florida Shelf associated with

the eddies on the boundary of the Loop Current, the structure of the large cold-core eddies off the

Dry Tortugas, and the behavior of warm rings in the western GOM.

Dr. Vukovich also collaborates with the National Marine Fisheries Service, Beaufort, NC, on the

potential transport of G. breve from the GOM to the North Carolina shelf and the subsequent

initiation of a red tide boom.

Robert Leben' s primary expertise is in satellite altimetry and its application to ocean circulation

monitoring. He is also interested in computational fluid dynamics and digital signal processing

techniques and their application to problems in geophysical fluid dynamics and aerodynamics. Dr.

Leben is Research Associate Professor at the Department of Aerospace Engineering Sciences,

Colorado Center for Astrodynamics Research, University of Colorado, Boulder.

Bisman Nababan is a Ph.D. student at the University of South Florida under Frank Muller-Karger.

He has an M.S. from Nova University and is interested in remote sensing applications to address

general ecosystem issues in marine science.
419

NEARSHORE BOTTOM PROPERTIES OVER THE NORTHEASTERN SHELVES OF

THE GULF OF MEXICO AS OBSERVED DURING EARLY MAY 1998

Dr. Worth D. Nowlin, Jr.

Dr. Ann E. Jochens,

Dr. Matthew K. Howard

Dr. Steven F. DiMarco

Department of Oceanography

Texas A&M University

INTRODUCTION

Texas A&M University is carrying out the Northeastern Gulf of Mexico Physical Oceanography

Program: Chemical Oceanography andHydrography study sponsored by the Minerals Management

Service (MMS) of the U.S. Department of the Interior under MIVIS OCS contract No. 1435-01-97-

CT-3 085 1. As part of this program we are conducting seasonal sampling for physical and chemical

oceanographic properties of the northeastern Gulf shelves between 89°W and 27.5N.

The second cruise of that program, N2, took place from 5 through 16 May 1998. This report briefly

describes the results of this May 1998 NEGOM cruise, with a focus on nearshore bottom properties.

BACKGROUND

Figure 1 H. 5 shows the locations of CTD/bottle stations occupied during cruise N2. Numbers are in

sequence of occupation. Lines are referred to as 1 through 11 from west to southeast. Lines 4-11

were occupied in reverse order beginning with 11, after which, lines 1-3 were occupied in that order.

Surface meteorological observations are generally available from 16 locations including coastal and

offshore stations. We examined surface winds from ten of those locations for the period April

through August 1998. There was good spatial coherence of the wind field for this period. During the

month of May surface winds were generally toward the east with weak speeds averaging near

4 rn-s1. Such winds are favorable for near coastal upwelling, but are weak.

Figure 1H.6 shows the sea surface height anomaly (SSHA) from satellite altimeter data averaged

over the period 21 April - 4 May 1998, just prior to the beginning of cruise N2. Seen are two

anticyclonic features impinging on the shelf edge in the region of DeSoto Canyon and west of

Tampa. In the final section of this paper we present a description of the changing circulation off the

shelf for the period April through August of 1998 based on study of weekly SSHA fields.

PROPERTIES OBSERVED ON CRUISE N2

The distribution of geopotential anomaly for the sea surface (3 m) relative to 800 rn (Figure 1H.7)

shows an anticyclonic feature over the DeSoto Canyon and a second anticyclone encroaching over
420

31 N

30N

29N

28N

2TN

r1

CTD/Bottle - 99 Stations

Station I is test station

V SAICMooiings

NDBC/CMAN Stations

.70 '-.-

.9 .54

B

.14

.15

1 6

c5

.9

90.w B5W 84W 83W

Missièsip lab Flöid

86W

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Figure 1H.5. Station numbers for CTD/bottle stations on cruise N2 conducted during 5-16 May

1998; locations of four SAIC moorings on 100-m isobath along northwestern wall

of DeSoto Canyon; and locations of two nearshore meteorological stations.

the outer shelf edge west of Tampa. The circulation indicated by these features is substantiated by

shipboard ADCP measurements, also shown in Figure 1H.8. The gridded ADCP vector field at 50

m is representative of other levels as well. An anticyclonic feature is seen located over the upper

canyon (centered near 29°N, 87°W). There is evidence for along-isobath flow along the northern

edge of the canyon and cross-isobath flow, directed inshore, at the canyon axis. This results in

inshore penetration of deep water along the canyon sides. Such a flow will lead to transport in a

bottom Ekman layer that is to the left of the flowleading to even more penetration of bottom

waters upslope in the canyon. Upwelling is clearly seen in the bottom distribution of temperature

(Figure 1H.8), showing maximum inshore penetration of cool bottom water near the head ofDeSoto

Canyon (lines 5 and 6).

Vertical sections of hydrographic properties provide clear evidence that onshore, near-bottom flow,

extending in most cases to the innermost stations (10-rn isobath), had occurred prior to the cruise.

Figure 1 H.9 upper shows temperature in vertical section on line 5. This is characteristic of the

situation observed on lines 1-7 west of Cape San Bias. Apparently, upwelling had been strong prior

to the time of the cruise, as evidenced by cooler water at the bottom at the innermost stations.

Southeast of Cape San Blas (lines 8-11) this onshore upwelling generally did not extend to the

shallowest stations, as can be seen from the distribution of bottom temperature (Figure 11-1.8).

89W 88W 87W
421

88W 8TW 86W 85W 84W 83W 82W

Figure 1116. Sea surface height anomaly from satellite altimeter data showing study area averaged

for 21 April-4 May 1998 (courtesy of Robert Leben, University of Colorado).

The high vertical stability associated with the temperature distribution is enhanced west of Cape San

Bias by a layer of relatively fresh surface water. On lines 3-7 the freshest surface water was found

offshore; Figure 1H.9 (lower) shows the distribution on line 5. This could have been caused by

nearshore upweiiing moving surface water offshore or by advection from the west due to the

anticycionic circulation over DeSoto Canyon. On lines 1 and 2 the freshest surface water was

observed at the inshore stationsevidence of local river sources for this water. East of Cape San

Bias, the freshest water was also found in the surface layers at the inshore stations. The extent, core,

and possible source of the fresh water lens may be deduced from the surface (3.5 m) salinity

distribution shown in Figure 1H.1O.

The combination of cool bottom water and a lens of fresh surface water produced a very strong

pycnocline over the inner and mid shelf regions. West of Cape San Bias the pycnocline was much

stronger than to the east; compare the distribution for line 3 with that for line 9 (Figure 1H. 11). It is

likely that this stability contributed to the relatively low oxygen values found at the bottom over

much of the survey region (Figure 111.12). Many values were near 3 mLL' and values approached
ipp fla M..iIe Pasca' .LiIa Figure 1H.7. Gridded shipboard ADCP vectors at 50 m plotted on contours of geopotential anomaly of 3-rn 

800 m.
Figure 1H.8. Potential temperature (°C) near the bottom on cruise N2, 5-16 May 1998.
424

100

0

E

71 70 69 68 67 66 65 64 63

100

0

Is S S T S i I a

24

24

22

36.2

22

Figure 1H.9. (Upper) potential temperature (°C) and (lower) salinity on line 5 of cruise N2, 5-16

May 1998.

20 50 100 150

71 70 69 68 67 66 65 64 63 F .30 - rr\ 1- 5 a

30 34

36i

3

.2 )

36.2 36.2

36 2

50 100 150
Figure 1H.lO. Salinity at 3.5 m derived from CTD data collected on cruiseN2, 5-16 May 1998.
426

Figure 1H.11. Density anomaly (Oe in kgni3) on lines 3 and 9 on cruise N2, 5-16 May 1998.
31°N 30°N 29°N 28°N 3.07- 3.54 3.07 3.01 3T- .91 2.79 26 8 3.2. 2.63 3. 3.5281 2 3.2: 2.89 2.73 - 94 0 I I I F I F I I F I I F F F I I [ I- I F 1 I I I F I F I I- I 1 F I- 1 I I F F F I I I- I F F I I I I I 

27°N F F F F F F F F F 1 i I F F F I F I F F F F F I F I I I F F 88GW 87°W goow 89°W 3.74 \ 464 

3.06 \4.25 F 9 3.04 tF 

4243. 732.7421 8 311 3.85 4.09 

F F F F F F 85°W 3.7IF iii F 84°W F h

83

Figure 111.12. Dissolved oxygen (mLL') near the bottom on cruise N2, 5-16 May 1998. F F F I F II F F 86°W
428

2 mL-L1 near the Mississippi Sound. Dissolved oxygen values at the bottom were not particularly

low east of Cape San Bias. That could have been due to differences in stratification or to the fact that

the region east of the Cape was sampled earlier in the cruise.

Percent iight transmission at the 660 nm wavelength observed during cruise N2 on lines 4 through

11 was generally at least 80% to greater than 90%. These high transmission values in the cool bottom

waters nearshore give ftirther evidence that these are upwelled offshore waters. By contrast, as we

approached the Mississippi Sound, light transmission decreased inshore, toward the surface, and to

the west.

Nutrient distributions over the mid-and-inner shelf appear elevated at locations corresponding to the

cooler upwelled waters. High nitrate values at the bottom seem well correlated with low oxygen

values. The 3.5 m and bottom distributions of nitrate observed on cruise N2 are shown in Figure

1 H. 13. Effects of river discharge and primary production are clear in the surface distribution. The

bottom distribution shows the effects of onshore movement of nutrient rich bottom waters and may

be compared with bottom oxygen distributions shown in Figure 1H.12. The distributions of silicate,

phosphate, and nitrite at 3.5 m and near the bottom based on cruise N2 measurements show the

expected good agreement with nitrate.

EXAMINATION OF TEMPORAL CHANGES

In search of cool upwelling events prior to cruise N2 or during the summer of 1998, we examined

time series of temperatures from SAIC moorings in the DeSoto Canyon from early April to early

August 1998 (SAIC 1998). We focused on near-bottom temperature observations from four

moorings located along the 100-rn isobath: Al, Cl, Dl, and El (see Figure 1H.5 for locations).

Lower than average temperatures were recorded during periods in April and early May at Cl, Dl,

and El. During two periods in mid-April pulses of cool water appeared at mooring locations Cl and

Dl at approximately the same time. These cool water pulses appeared at El, at the head of DeSoto

Canyon, about ten days later. This cool water penetration over the 100-rn isobath was not seen at Al.

(We examined temperature records at the bottom at Al and B 1 for March and early April and found

no indication of such penetration.) These intrusions likely set the stage for the cool bottom water

observed during cruise N2.

Another influx of cooler water over the 100-rn isobath occurred in mid-July. Again its presence was

noted at Dl about ten days before El. The intensity of this intrusion was less than those in April.

We examined nearshore records from meteorological stations 42007 and Dauphin Island (see Figure

1 H.5 for locations) for surface temperature. At both locations there was a pronounced warming trend

during spring, as expected. A cool event lasting several weeks with a magnitude near 50 C occurred

at both locations in early June 1998.

Mean surface winds for the AprilAugust 1998 period were generally eastward (upwelling favorable)

and onshore. However, at the end of the first week in June a strong offshore wind event occurred
429

31 °N

300N

29°N

28°N

27°N

31°N

3oN

9OW

29°N

28N

III VII 'liii ii 'I 'jI'ih' 'i'iiIi

.i'iI r.--

27°N

89°W 88°W 87°W 86GW

0

85°W

'I

84GW 83W 82°W

:1 I IIf

I

I'll'''''' 11111

9OW 89°W 88GW 87°W 86°W 85°W 84°W 83°W 82°W

Figure 1H.13. Nitrate (tmo1L') at 3.5 m (upper) and near the bottom (lower) on cruise N2, 5-16

May 1998.
430

from the Mississippi Sound to Cape San Bias. This event apparently drove offshore flow and

upwelling because it corresponds with the cool event in observed surface temperatures.

Because off-shelf cyclonic and anticyclonic eddies have such profound influence on the outer shelf

circulation in the northeastern Gulf, we studied the development of these features by examining the

evolution of SSHA over the northeasternGulf of Mexico (depths greater than 200 m) using a product

prepared by Robert Leben (University of Colorado) based on a combination of altimeter data from

TOPEX/POSEIDON and ERS-2. We looked at one SSHA distribution per week beginning 1 April

1998 and continuing through August 1998. These SSHA distributions are in fact a temporally

smoothed product using data over about a ten day period centered near the day identified. The data

have been temporally and spatially smoothed using decorrelation scales of 12 days and 100 km

Therefore, features may tend to be weaker than in reality, and smaller scale features may have been

removed.

On 1 April most of the off-shelf area was under cyclonic flow except for one small anticyclone over

DeSoto Canyon. A strong extension of a large anticyclone centered at 25.5 °N, 88 °W extended

toward the shelf break west-southwest of Tampa. By 8 April the anticyclone off Tampa had extended

to the 200-m isobath and, after separation ofa weak anticyclone near the shelf edge, it subsequently

withdrew offshore. By 29 April shortly before the beginning of cruise N2, the anticyclone over

DeSoto Canyon had strengthened. Shortly thereafter the two anticyclonic features at the shelf edge

extended toward one another, coalesced and strengthened, resulting by 30 May in a peanut-shaped

feature, similar to but more intense than that seen in Figure 1H.6.

By 1 July the feature had strengthened to a height anomaly of more than 20 cm and straightened into

an east-west orientation. Then, connections began to form with a larger anticyclonic feature to the

south until by 22 July both ends of the anticyclone appeared to be connected to the larger

anticyclone. During the next three weeks, it again separated and diminished somewhat in spatial

extent. By the end of August, the feature had renewed a connection with an anticyclone to the

southwest and was oriented over the axis of the DeS oto Canyon with considerable strength.

There may be some evidence for the counterclockwise movement along the continental slope of

small anticyclones. However, the reality of weak features in the SSHA field near the shelf edge

probably should be viewed with caution.

REFERENCES

SAIC. 1998. DeSoto Canyon Eddy Intrusion Study. Data Products: Set 4 April 1998-August 1998.

SAIC, Raleigh, NC 27605.

Worth D. Nowlin, Jr. is a distinguished professor at Texas A&M University in the Department of

Oceanography. His B.A. and M.S. are in mathematics; his Ph.D. in oceanography. His principal

research interests are in meso- and large-scale oceanic distributions of properties, shelf circulation,
431

dynamics of ocean circulation, long-term and systematic ocean observations for climate studies,

research planning and management. His publications focus mostly on the American Mediterranean

(especially the Gulf of Mexico), the Antarctic Circumpolar Current, relationships between the

Southern Ocean and the global ocean, and sustained observing systems.

Ann E. Jochens is an associate research scientist at Texas A&M University in the Department of

Oceanography. She has a B.S. with Honor in mathematics and statistics, a J.D. with specialty in

ocean law, and M.S. and Ph.D. in oceanography. Her principal research interests are processes at the

boundary of coastal and open oceans, physical oceanography of the Gulf of Mexico, meso- and largescale shelf and slope circulation and property distributions, ocean law and policy, and management

of oceanography research projects. Her publications focus mostly on oceanography in the Gulf of

Mexico.

Matthew K. Howard is an assistant research scientist with the Department of Oceanography at Texas

A&M University. His B.S. and Ph.D. degrees are in oceanography. His interests are in coastal ocean

processes, analysis of observations, and air-sea interactions.

Steven F. DiMarco is an assistant research scientist in the Department of Oceanography at Texas

A&M University. His B.S., M.S., and Ph.D. degrees are in physics. His principal research interests

are the physical oceanography of continental shelves and slopes, particularly in the Gulf of Mexico,

the general circulation of the southwestern Indian Ocean, and decadal and interdecadal scale climate

variability of Texas and the southeastern U.S.

DE SOTO CANYON PHYSICAL OCEANOGRAPHY

Dr. Peter Hamilton

Science Applications International Corporation

Raleigh, North Carolina

iNTRODUCTION

The De Soto canyon study is presently investigating the circulation of the northeastern Gulf of

Mexico slope between the Mississippi delta and west Florida escarpment. Thirteen moorings all

equipped with upward-looking acoustic Doppler profilers along with a variety of current meters,

thermistors and conductivity sensors have been deployed since March 1997. Figure 1H.14 shows the

he positions of the moorings, wind stations (NDBC buoys and CMAN), and the hydrographic station

grid which is occupied every four months. The final retrieval and hydrographic cruise is scheduled

for April 1999. Data return has been excellent, and the year-long time series from the first year of

the study have had some preliminary analysis.
432

R/V/ PELICAN PE-9830 3/31/98 10 4/10/98

9O.W 89W 8W 87W 86W 85W

31N

31N

Mississippi

89W

Florida

87W

D2 034 045

CS

86W 85'W

Figure 1H.14. Map of mooring positions (solid dots), standard grid hydrographic (CTD) stations

(open squares), and meteorological buoys and CMAN stations (solid diamonds).

CIRCULATION CHARACTERISTICS

The slope circulation is dominated by relatively small scale (' 50 to 100 km diameter) warm and

cold eddies. Examples of near-surface, geostrophic velocity vectors, relative to 1,000 dbars, are

given in Figure 1H.15 for two of the hydrograhic surveys. In March 1998, the circulation pattern

showed three eddies (two cyclones and an anticyclone) on the lower slope with weaker eddy flows

over the shelf break, just east of the delta and at the head of the De Soto canyon. These lower slope

eddy circulations can advect warm, salty surface water from the Loop Current region to the south

I

30N

- 29N

.3.

30°N

29°N -

28°N

gow

.07 77

U

V EtI

EJ 7D 0

7q3 D2#

B2 --------- 074

AO.-- H3 ca

0
433

a)

b)

R/V/ PELICAN PE-9830

3/31/98 TO 4/ 8/98

9O1 59W B&W 87W g5W 85W

31'H I 31M

40 cm/s

30N -

29N -

31DM

30t1

29N

28N

I

89.w

R/V PELICAN PE-9908

9cW B9W B8W 8 rw

30M

29N

87W 85W

& - 1000 m. GeostrophC Velocity

28N

8/ 4/98 TO 8/12/98

8W E5W

31 H

I

I 88W 87W 8EW 55W

6 - 1000 m. Geostrophic Velocity

30N

ZN

28N

Figure 1 H. 15. Geostrophic velocitiesrelative to 1,000 dbar calculated from CTD data for the March

(PE-9830) and August (PE-9908) hydrographic cruises.

26N -

g°.w
434

and also export brackish shelf and/or Mississippi plume water across the slope. The August 1998

survey (Figure 1 H. 1 5b) showed the lower slope dominated by a larger scale anticyclone that was

generating strong eastward currents along the Mississippi and Alabama shelfbreak. This upper slope

eastward jet bypasses the head of the De Soto canyon generating a cyclone in this region. The

interaction between the cyclone and the jet produces a strong convergence and export of shelf water

near mooring Cl, and onshore flow on the other side of the canyon near mooring El. An eastward

jet-like flow along the upper slope is relatively common in these measurements and is usually

accompanied by a counter-current flowing westward below about 200 m depth. The eastward and

westward flows above and below about 200 m, respectively, are also apparent in the year-long mean

current statistics for the upper slope.

The subtidal current velocity, temperature and salinity time series show quite differentcharacteristics

between the summer and fall of 1997 and the winter and spring of 1998. In the summer of 1997, flow

events along the shelf break were sustained over several weeks and apparently dominated by slow

moving eddies over the slope. In the following winter, events were short-lived with periods of 10

days or less and considerably more energetic. One of the strongest current events that were not

related to passage of a hurricane, occurred at the beginning of February 1998. This event generated

westward currents at Cl that exceeded 80 cmls over a large portion of the 90 m water column and

lasted about one day. Time series of temperatures (Figure 1 H. 16), from near the bottom at the shelf

break moorings, illustrate the many short-lived cold events that occurred from December to April.

There is evidence that the events are propagating westward along the slope from El around toAl.

Deeper current and temperature fluctuations were also more energetic in winter than in summer and

showed evidence of westward propagation of wave-like signals. The reasons for the change in

character of the circulation are not clear but may not be a result of seasonal changes in forcings such

as the wind. The winter period in offshore waters to the south was dominated by the formation and

detachment of a major Loop Current anticyclone (eddy Fourchon). This could have had indirect

effects on flows over the northeastern Gulf slope.

Figure 1H.16 also shows that cold water was present at the head of the canyon (Dl and El) in June

and July of 1997 but not in the summer of 1998. Thus, the coastal upwelling along the Florida

Panhandle coast that was reported during the summer of 1998, and is discussed elsewhere in this

session, did not have exceptionally cold bottom water as a source at the shelf break. However, the

water column in July is highly stratified with top to bottom differences of 8 to 10 °C at the shelf

break. Thus, shelf-edge bottom temperatures of less than 20 °C would show up as being relatively

cold in satellite imagery if they were upwelled at the coast.

CONCLUSIONS

This ongoing physical oceanographic study of circulation in the De Soto canyon region has been

designed to resolve eddy flows and shelf-break exchanges with short horizontal length scales of

order 25 to 50 km. Preliminary results indicate that over the limited region of the study, the

measurements are resolving the important energetic small scale eddies that dominate the circulation.

The experiment has also shown some dominant patterns of upper slope flows and eddies that were

previously unknown.
0I, 25.0- 22.5 -E 20.0 - 17.5 : 1 5.0 - 1 2.5 - II 19 10 30 19 7 27 16 4 26 15 4 23 2 H A H J J A 5 0 N 0 .J F H A H J J A S 1998 JuLan ay 50 2/19/1997 Shilf Br,ok 9ottom Timp.raIur. S

Figure 1H.16. 40-hour low-passed filtered temperature time series from the near-bottom instruments at the shelf

(Al through El). Top plot is from the 180 m level of the D9 mooring in the canyon. Plots withouhave the same temperature scale as the Al time series.
436

Dr. Peter Hamilton is a Senior Oceanographer with Science ApplicationsInternational Corporation.

He has served as a Principal Investigator on many MMS programs. He received his Ph.D. from the

University of Liverpool (U. K.) in 1973.

MODELING CURRENTS IN NORTHEASTERN GULF OF MEXICO:

AN EVALUATION

Dr. Y. Hsueh

Dr. Yury Golubev

Department of Oceanography

Florida State University

INTRODUCTION

The main goals of this paper are (1) to simulate currents in the Northeastern Gulf of Mexico

(NEGOM) using an ocean circulation model, and (2) to make an evaluation of the model ability in

reproducing the observed patterns of surface velocity.

To simulate the flow, a limited-area, primitive-equation model is developed, based upon the

Bryan-Cox code (Cox 1984), originally designed for modeling the general circulation of a closed

ocean basin. The model has sufficient resolution for the simulation ofmesoscale dynamics involved

in the interaction between the Loop Current, the main circulation feature in NEGOM, and the

continental margin topography.

To assess the model's ability in reproducing observed flow features. we make use of two sources of

data. The first one is the average surface velocity calculated from the distance traveled by surface

drifters between successive position fixes. Drifters were tracked in NEGOM during February

1996May 1997 (P. P. Niiler, pers. comm. 1998). The second data source is the current meter

measurements on moorings in DeSoto Canyon during March 1997 - April 1998 (SAIC 1998).These

data sources allow us to make an objective evaluation of model results. We base our evaluation on

statistical estimation as well as on inspection.

METHODS AND RESULTS

Numerical Experiments

A relevant model for the Gulf of Mexico circulation driven both by the inflow through the Yucatan

Straits and by the wind stress must resolve dynamic processes at the shelf and over the sharply
437

changing topography in NEGOM. The eddy-resolved circulation model employed to meet this

requirement is the rigid-lid, primitive-equation model of Bryan and Cox (Bryan 1969; Cox 1984).

A uniform grid with a 1/6 degree grid spacing is used that covers the domain between 18 N and 31

N and between 80 W and 100 W. The vertical grid is stretched with 8 levels in the top 200 m, a total

of 16 levels in upper 1 ,000m, and 14 remaining levels spanning the water column the rest of the way

to a maximum depth 5,500 m. With this grid, both the continental shelf and the continental slope

topography are reasonably resolved.

Bathymetry for the modeled region is formed from selecting depth values from every second point

in the 5-minute ETOPO global relief model, which is based on Digital Bathymetric Database

5(DBDB5) created by the U.S. Naval Oceanographic Office. All values greater than 5,500m are

assigned to level 30, the deepest level of the model. The entire depth field is then smoothed with a

nine-point smoothing scheme and then truncated at 20m at the edge of land masses to produce the

model bathymetry.

Temperature and salinity at open boundaries are relaxed to climatological values. Horizontal

velocities are relaxed to values calculated from the thermal wind relation on the basis of the

climatological temperature and salinity. The relaxation is reduced in strength gradually in a buffer

zone spanning 6 grid points inward from the open boundary. No relaxation is present further inward.

No diffusive fluxes are allowed normal to the open boundaries. Finally, along the outflow boundary

through the Straits of Florida, a radiation condition is implemented (Carmelengo and O'Brien 1980).

At lateral solid boundaries, no-slip velocity and no-normal-flux tracer conditions are impossed. At

the rigid-lid surface where the vertical velocity vanishes, the heat and salt fluxes are provided

through a relaxation to climatological temperature and salinity values on a 50-day time scale. At the

ocean bottom where the flow is constrained to be parallel to the sea floor, a bottom stress quadratic

in bottom velocity is applied. There is no flux of heat or salt through the sea floor.

Two sets of numerical experiments were conducted. The first one covers the time from February

1996 to March 1997 and is for comparison with the drifter data. The second set covers the period

of March 1997 to April 1998 to allow comparisons with the mooring data. In all experiments,

6-hourly 10 m surface winds from the NCEP/NCAR 40-year reanalysis data set (Kalney et al. 1995)

were used to calculate the wind stress.

Results of Analysis

Figure 111.17 shows the horizontal distribution of correlation coefficient (CC) for both components

of velocity. In this case, CC at each point of domain was calculated for velocity components (model

and drifters) at the time when drifter velocities are available. Maximum correlation is found on the

shelf of NEGOM and CC decreases seaward. The main difference is that CC in the zonal component

has high values (more than 0.7) along the northern shelf between 86 and 88 W whereas CC in the

meridianal component has minimum values there. So, in this region the model simulates much better

east-west component than south-north component. Figure 1 H. 18 presents the time series of CC. In

this case, CC was obtained for each day from velocities at the points where drifter velocities are
438

2790 89 88 87 86 85 84 83

Longitude

Figure 1 H. 17. Correlation coefficient between velocities derived from position fixes of surface

drifters tracked during February 1996 and April 1997 and model velocities at 5 m as

a function of horizontal coordinates for Northeastern Gulf of Mexico. The upper

panel is for the east-west velocity component and the lower panel is for the

south-north velocity.
439

1

0

1

-2

50 100 150 200 250 300 350 400

/

1

Figure 111.18. Time series of correlation coefficient as in Fig. 1 but area-averaged daily during

February 1996 - April 1997 for the east-west velocity component (upper panel) and

south-north velocity component (middle panel). The time series of south-north wind

stress component at Pensacola is shown in the lower panel.

available. We note the relatively small values of CC approximately between the 70th and 200th day,

especially for the east-west component of velocity. This time (summer time of the year) is

characterized by weak winds in NEGOM (bottom of Figure 111.18). In contrast, the model seems to

simulate drifters velocity in cases of moderate to strong winds. Two examples are presented in

Figure 1H.19. The first example (left panel of Figure 1H.19) shows that strong winds from the

northwest on 20 March 1996 produces strong model flows to the southeast along the edge of the

Western Florida Shelf (WFS) with maximum velocity of 0.7 mIs. The drifter velocity (bottom panel)

shows qualitatively the same. The second example shows that winds from the east on 6 October 1996

produces model flow to the west along the coast with velocities as large as 1.1 mIs near the

0

50 100 150 200 250 300 350 400

2

50 100 150 200 250 300 350 400

Days, starting from February 7, 1996
440

30

C)

29

Cu -J

28

-90 -88 -86

Longitude

30

C)

29

Cu -J

28

Figure 1H.19. Vector plots, in the DeSoto Canyon area, for 20 March 1996 (left column) and 6

October 1996 (right coluum) of wind stress (upper panel), model velocity at 5 m

(middle panel), and velocity derived from satellite-tracked surface drifters (lower

panel).

Mississippi river mouth. The drifter velocity shows about the same. So, the model simulates well

the wind-driven currents in NEGOM.

Following Holloway and Sou, 1996 (refered hereafter as HS) we consider the skill of the model in

reproducing currents in NEGOM. For skill estimation, we use data from current meter moorings in

DeSoto Canyon. At each current meter position, time mean (ul,vl) of velocity is calculated for the

entire record length. The same is done with model velocity (u2,v2) at that position. The kinetic

energy of the difference f(u2-u1,v2-v1) is the error kinetic energy, eKE .5*f(1/V)*fwhere V is

C)

30 I S.'

a)

30

29 29

Cu (C -j -J

28 28

-go -88 -86 -84

-90 -88 -86 -84

-88 -86

Longitude

-90 -84
441

the diagonal matrix of total variance for each current meter position. We compare eKE with the

kinetic energy of data themselves dKE and consider the following quantity:

skillE(dKE - eKE)/(dKE + eKE)

With an error-free model with eKE = 0, we have skillE 1. Whereas with a model with large error,

we have skillE = -1. We consider also the skill of a completely skill-less model which gives flows

randomly unrelated with observation. Denote the weighted kinetic energy of the model at the current

meter locations by mKE. The skillE for this skill-less model is called skiliF (for floor"):

skiliF = -mKE/(2dKE + mKE)

The difference between skillE and skillF gives an energetic skill of the model, i.e., the excess of

skillE over skiliF.

A second measure of model skill is the direction skill (skiliD) which shows if the model has any skill

in reproducing the flow direction, regardless of the speed. From unit vectors of velocity

dD/IDI(data) and m=M/IMI(model) we form the weighted inner product:

skillD = d*(l/V)*m

The values of SkiliD also fall within the bounds -1 <skillD< 1.

Results of skill calculations are presented in Table 1H.2 for 12, 32, 52 and 72m. Both skillE-F and

skillD have high values, especially if we compare them with estimations made by HS for the world

ocean. The highest estimations obtained by Holloway and Sou are 0.19 1(+/-0.046) for skillE-F and

0.292(+/-0.081) for skillD. The main reason of the difference between these estimations and our

values is 1) we used horizontal resolution in the model 1/6 degree comparatively with 1.856 in HS;

2) we used NCEP wind to drive the model which is more close to reality than mean

Hellerman-Rosenstein fields used by HS.

As the table shows, all skills decrease systematically with depth. It allows us to conclude that the

model gives reliable result in the upper layer where the current is basicaly wind-driven. The last line

in the table represents estimations made with drifter data. SkillE-F now is less than in the case of

mooring data but direction skill even a bit higher. The low skill here might be due to the fact that the

time mean of drifter velocity contains large variability.

SUMMARY

Now we can make the following brief summary of the obtained results. We judge the ability of the

model to reproduce observed surface velocity as quite satisfactory. Basically the currents on the shelf

are wind-driven. That is why the model works well in the fall, winter and spring when winds in

NEGOM are relatively strong. In summer when the winds are weak, the correspondence between the

model results and the observations deteriorates.
442

Table 1H.2. Evaluation of the skill of the model to reproduce observed events.

The model results are close to observations on the NEGOM shelf. In the vicinity ofDeSoto Canyon

the model reproduces the observed east-west component of velocity heifer than the observed

south-north component of velocity. In regions seaward of the shelf, the correlation between model

results and observations deteriorates.

In terms of mean velocities, the model appears to have high skills for both the current kinetic energy

and current direction for the upper layer. Model skills declines with increasing depth.

ACKNOWLEDGMENTS

We thank Thomas Berger and Peter Hamilton of Science Applications International Corporation who

kindly supplied the current meter data.

REFERENCES

Bryan, K. 1969. A numerical method for the study of the circulation of the world ocean.

J.Comput.Phys.,4 :347-376.

Carmelengo, A.L. and J.J. O'Brien, 1980: Open-boundary condition in rotating fluid. J. Comp.

Phys., 35, 12-35.

Cox M.D. 1984. A primitive equation three-dimensional model of the ocean. GFDL Ocean Group

Technical Report,1,GFDLINOAA, Princeton University,Princeton, NJ, l44pp.

Halloway, Greg, and Tessa Sou, 1996: Measuring skill of a topographic stress parametrization in a

large-scale ocean model. J. Phys. Oceanogr., 26, 1088-1092.

Depth(m) skill E skill F skill E-F skill D

12 0.088 -0.516 0.603 0.712

32 0.067 -0.479 0.547 0.702

52 0.015 -0.417 0.431 0.529

72 0.024 -0.343 0.367 0.422

Drifters -0.230 -0.433 0.203 0.748

0.19 1 0.292

Holloway & Sou, 1996 (+7-0.046) (+7-0.08 1)
443

Kalney, E., et aL, 1996: The NCEP/NCAR 40-year reanalysis project. Bulletin of the American

Meteorological Society, 77, 437-471.

Science Applications International Corporation, 1998: DeSoto Canyon eddy intrusion study. Data

Products: Set 2 and Set 3. Science Applications International Corporation, Raleigh, North Carolina.

Dr. Y. Hsueh is Professor of Physical Oceanography at Florida State University. His research areas

are physical processes in continental shelf waters which produce variabilities in sea level, currents,

and in water properties. Dr. Hsueh received is B.S. in civil engineering from the National Taiwan

University in 1958 and his Ph.D. in geophysical fluid dynamics from Johns Hopkins University.

Dr. Yury Golubev is a research associate at Florida State University. He received his M.S. degree

in physical oceanography from Odessa Hydrometeorological Institute in 1976 and his Ph.D. in

marine sciences at the Marine Hydrophysical Institution in 1981. His research interests include ocean

modelling, circulation in closed and semi-closed basins, and large-scale ocean-atmosphere

interaction.

PRELIMINARY REPORT ON COASTAL UPWELLING AND MASS MORTALITIES IN

THE NORTHEASTERN GULF OF MEXICO DURING SPRING AND SUMMER 1998

Dr. Sneed B. Collard

University of West Florida

INTRODUCTION

A widespread, protracted period of coastal upwelling occurred in the northeastern Gulf of Mexico

(NEGOM) during spring and summer 1998. During the upwelling event, dense algal blooms and

mass mortalities of fishes and invertebrates occurred from shore to depths of about 35 m in the

central Florida Panhandle. This report briefly summarizes climate and ocean conditions during the

period, and suggests possible causes and proximate biological consequences of upwelling in the

affected area.

BIOLOGICAL OBSERVATIONS

From mid to late May, coincident and apparently associated with upwelling, commercial divers

reported mass mortalities of fishes and invertebrates on wrecks and reefs at depths of 10-35 m (the

limit of diver excursions) in a region approximately 20 km east and west of Panama City and 3-7 km

offshore (Fitzhugh pers. comm.). At about the same time, fishermen reported blue runners (Caranx

fusus or C. crysos) and vermillion snappers (Rhomboplites aurorubens) floating on the surface
444

offshore Panama City. According to commercial divers, fishermen and professional biologists, the

areal and depth distribution of dead marine animals closely approximated the distribution of cool

water which moved on and offshore on the surface, or beneath a strong themiocline reported to occur

at depths of 3-12 m.

On 8 June, following a period of offshore winds and nearshore upwelling (Nowlin et al. 1998), a

dense population of a cool water-tolerant filamentous red alga, Heterosiphonia cf. gibbesii

(Moncreiff via Shaffer pers. comm.) was reported along and offshore Panama City beaches.

Concentrations of Heterosiphonia appeared to move on- and offshore with cool water at irregular

intervals, and reports of thick mats of algae in the water column and on the bottom continued until

12 July. After 12 July concentrations of Heterosiphonia markedly decreased when the population

died off or was cleared from the area by winds and currents. Accumulations of algae in St. Andrew

Pass, on area beaches, and in coastal waters were usually associated with dead fish and invertebrates

(Shaffer pers. comm.).

On 25 June, large numbers of dead fishes and invertebrates were reported on reefs off Destin in

water depths of 18-21 m. At a depth of about 12 m "colder than normal" water was encountered, and

currents were reported to be eastward. On 1 July, National Marine Fisheries Service divers reported

a strong thermocline at 5-6 m in St. Andrew Pass, and reported that all of the organisms seen below

6 m were dead except for crabs, which were moribund. Above the thermocline, fishes generally

associated with deeper water or bottom habitats were seen (Table 1 H.3). At 14 m depth, bottom

water temperature, salinity, and dissolved oxygen concentration were, respectively, 190 C, 35.3 psu

and 0.37 mg 11.

During low tides on 1-2 July, NMFS biologists observed distressed fish in St. Andrew State

Recreation Area tidal pools; dead juvenile flounders, crabs and lethargic fishes inside the St. Andrew

Passjetties; and dead eels, burrfish, cowfish, crabs, starfish and sea cucumbers outside the pass, and

on area beaches (Table 1H.3). Water at the beaches was characterized as green and thick with algae.

Mass mortalities did not recur (or were not reported) in the Panama City-Destin area during 3-6 July,

and nearshore Gulf waters were reported to be clear and well mixed, with reduced algal densities.

While fishkills were not reported during this four-day period, large schools of lethargic fish (Spanish

mackerel, "baitfish," and stingrays) were seen in the shallows at Destin Pass.

During the period 26 June-12 July, distressed, moribund and dead fishes and invertebrates were

observed from the intertidal zone to about 30 m depth in the St. Andrew Bay-Destin region.

Deepwater animals were observed at the surface offshore, and in shallow water near shore during

this period, and algal densities were observed to be much higher than usual. From 7-14 July, water

temperatures at Panama City beaches varied between 18-20° C. Cool water arid mass mortalities

similar in magnitude and species composition to those of 1-2 July, recurred in the Destin-Panama

City area from 7-9 July, and fishermen reported that highly stratified water, with currents setting to

the east, extended 24 km offshore. On 10 July, the water column was wealdy stratified (21 °C on the

surface, and 19° C on the bottom at 12-13 m) in St. Andrew Pass, and strongly stratified 1.6 km

offshore (25° C on the surface and 190 C at 12-13 m). Fishermen reported that bottom currents were
Astroscopus y-graecum (D)

French grunts (D)

white grunts (D)

pigfish (D)

brotulas (D)

Opsanus beta (D/S)

redfish (S)

Hemipteronotus novicula (D)

Citharichthys spilopterus (D)

blue ninners (D)

wrasses (D)

parrotfish (S)

Rhomboplites aurorubens (D)

juvenile and adult flounders (DIS)

eels (D)

cowfish (D)

stingrays (5)

grouper (D)

scorpionfish (S)

skates (D/S)

Invert

snails (D)

sea slugs (D)

sponges (D)

tunicates (D)

deepwater crabs (5)

rock shrimp (5)

jellyfish (D)

crabs "many species" (D/S)

Fishes

Syacium papillosum (D)

Centropristus striata (D)

spottail pinfish (D)

soapfish (D)

sennets (D)

rays (S)

black seabass (5)

Paralichthys albigutta (D)

Etropus crossutus (D)

cigarminnows (D)

electric rays (S)

snake mackerel (S)

leatherj ackets (D)

burrfish (D)

baitfish (S)

Spanish mackerel (5)

sharks (D)

batfish (D)

gag (S)

flatfish (D)

ebrates

Hepatus (D)

sea urchins (D)

starfish (D)

polychaetes (D)

'regular shrimp'(D/S)

clams (D)

sea cucumbers (D)

nudibranchs

445

Table 1H.3. Fishes and invertebrate groups reported by various observers to be either dead (D)

or obviously distressed (5). No systematic collections were made, and the list is

conservative. Common names are used when identification of the species was not

verified.
446

from west-to-east 16-64 km offshore. On 10 July, dead crabs, jellyfish and sharks washed up on

Pensacola beaches, but correlation between the deaths of these organisms and upwelling is uncertain.

On 11-12 July a diver reported surface conditions over the wreck Elvira located 6.4 kin south of

Destin in water 26 m deep, to be relatively warm ( 24°C) with 12 m visibility. At about 9 m depth

a strong thermocline was encountered, and the water was turbid, with visibility reduced to about two

meters. At a depth of about 14 m, water temperatures evened out' near 18° C, and visibility

increased to about 8 m. Numerous fishes were seen at 24 m, but these appeared to be sluggish.

Similar conditions were encountered at the wreck, Louise in 17 m of water, but "everything was dead

crabs, snails, clams, grouper, batfish, everything...

On 12 July, fishermen reported thousands of small flounder, rock shrimp, 'regular shrimp' and crabs

swimming on the surface in the New Pass area at St. Andrew Bay, and at Destin, live, deepwater

crabs were observed to be coming ashore in large numbers. Water temperatures during this time were

reported to be about 6.5-8.5°C colder than surrounding water in a 24-40 km wide band of water

extending from the Ochiockonee River to Pensacola. Cold water extended from a depth of 6 m

beneath the surface to the bottom, and was reported to be "black and murky."

From 13-16 July, charter boat captains and divers reported cool water inshore arid warmer water

offshore, with dense algae extending 9-10 km offshore. Surface temperatures were 21.7° C at

Panama City, and 25° C at Pensacola. On a line from 8 km south of Panama City to the St. Joe sea

buoy, surface and bottom (15 m) temperatures were 29.0° C and 20.5° C, respectively (FDEP pers.

comm.). On 17 July a commercial diver reported that large milky clouds of unknown composition

were seen about 9-10 km off Destin Pass, and that similar substances were observed in the pass on

4 July.

From 20-22 July, nearshore water became clearer, and surface temperatures increased to 27° C in

the Panama City area. Satellite images indicated that cool water had moved to the west, and on 19

July, large numbers of lesser electric rays were observed in clear, cool water along a 1.6 km-long

stretch of beach at Gulf Shores, Alabama, (Vittor pers. comm.). On 23 July NMFS reported that the

cold water event was dissipating and that water clarity was improving. Coastal winds in the Panama

City-Pensacola area shifted to the southeast on 24 July, sea surface temperatures increased to 29°C,

and fishers reported good catches of sharks, Spanish and king mackerel, grouper, snapper and redfish

from Panama City to St. Joe Bay.

From information collected by National Marine Fisheries Service, biologists and marine scientists

from other state and federal agencies (Fitzhugh et al. pers. comm.), mass mortalities on reefs

appeared to be catastrophic. Offshore areas were apparently affected at different times, as cool water

moved from east to west. For example, mortalities on reefs 20 km east of Panama City occurred in

May, while reefs west of Destin, but not as far west as Pensacola, apparently experienced mortalities

in June-mid July. Reports of dead fish floating on the surface offshore were received throughout the

ten-week period, while dead organisms washed up on beaches in the Panama City area were most

frequently observed between 27 June and 12 July.
447

In addition to reports of dead animals, numerous observations were made of fishes and invertebrates

exhibiting symptoms associated with low oxygen stress. Benthic species (e.g., shrimp, crabs, some

fishes) were seen swimming on the surface; lethargic fishes were observed below the thermocline;

and shrimp and crabs were reported to be crawling out of the water" similar to "jubilees" that

occur periodically in Mobile Bay due to low dissolved oxygen concentrations.

CLIMATE

Unusual climatic conditions in the NEGOM from winter 1997 through mid-summer 1998 were

attributable to complex interactions between a strong 1997-1998 ENSO and a persistent negative

phase North Pacific Oscillation (NP) teleconnection pattern (U.S. Department of Commerce 1997).

According to the U.S. Department of Commerce (1998 a), from January to mid-March 1998, the

southeastern U.S. experienced warm, stormy weather and heavy rainfall in advance of a pronounced,

ENSO-related high pressure ridge that extended over the tropics and subtropics. Rainfall amounts

increased as the ridge moved north, and large volumes of fresh water associated with floods in

southern Alabama, Georgia and Florida entered the northeastern Gulf of Mexico from Mobile Bay

to the Big Bend region of the Florida Panhandle during the second and third weeks of March (U.S.

Department of Commerce 1998 a, b). Peak discharge volumes of the Mississippi River (30,583 m3

sec') did not reach the Gulf until the third week of May, due to the northward reach of its much

larger watershed (Miller, U.S. Army Corps of Engineers pers. comm.). In late March, as the high

pressure ridge moved northward into the south-central United States, warm, wet weather in the

southeast was replaced by record-setting hot, dry conditions that persisted through late July, when

the residual effects of the 1997-1998 El Niflo on NEGOM climatic conditions dissipated (U.S.

Department of Commerce 1998 a, b, c). Coupled with atypical temperature and precipitation

patterns, regional winds were also influenced by the ENSO-ridge system and, after its movement to

the north, by a large atmospheric high pressure cell that dominated the Gulf of Mexico through most

of July.

It is useful to compare descriptions of average (i.e., non-ENSO) winds in the NEGOM with those

observed during spring-summer 1998. According to Blaha and Sturges (1981) winds are westward

and relatively calm during spring, and without a dominant east-west component from May-July.

Wolfe et al. (1988) and Tanner (1992) characterized prevailing spring-summer winds as

northwestward or northeastward; and SAIC (1997) described late spring and summer winds as

relatively calm and onshore, in agreement with Blaha and Sturges (1981).

Unlike these patterns, upper level and surface winds in the NEGOM were predominantly eastward

and northeastward under the influence of the northern arm of a large atmospheric high pressure cell

during spring-summer 1998 (Purdue University 1998). Nowlin et al. (1998) described regional

surface winds from April-August 1998 as generally eastward and onshore, with a strong offshore

wind event at the end of the first week in June. Sturges (pers. comm.) found that U-component mean

winds were predominantly eastward from January-mid-July, except for a month-long period of weak

westward flow from mid-March through mid-April. Price (pers. comm.) analyzed NEGOM surface

winds and demonstrated that May-June 1998 winds were more northeastward and eastward than in

May-June 1997.
448

OCEANOGRAPHY

Information presented here was extracted from the results of an extensive investigation of

hydrographic conditions and their evolution in the NEGOM from early April to early August 1998

(Nowlin et al. 1998). A complete dataset and detailed analyses may be found in in the source

document.

In a search for evidence of upwelling prior to cruise N2 in May, Nowlin et al. examined a time series

of near-bottom temperature records from five moorings located along the 100 m isobath in the

NEGOM. From west to east, mooring locations A-E were located, respectively, southeast of the

Chandeleur Islands, south of Mobile Bay, south of Pensacola Bay, southwest of Choctawhatchee

Bay, and southwest of St. Andrew Bay, at the head of DeSoto Canyon (SAIC 1998). Temperature

records indicated that two pulses of cool bottom water in April at moorings C and D were followed

some ten days later by a cool water intrusion at mooring E. There was no evidence of cool water at

100 m depths at moorings A or B during March or April. Cool water at moorings C, D, and E in

April apparently "set the stage" for more extensive upwelling observed during cruise N2 in May.

The SSHA field from April-August indicated the presence of a small anticycione over DeSoto

Canyon on 1 April. By 29 April this feature had strengthened, and by 30 May had coalesced with a

second anticyclone that translated northwest from its earlier position west of Tampa (see Nowlin et

al., Figure 1H.6). By 1 July the anticyclone over DeSoto Canyon strengthed to a dynamic height>

20 cm, assumed an east-west orientation and by 22 July connected with a larger anticyclone to the

south. After 22 July (at about the time when upwelling, mortalities and algal blooms off Panama City

stopped), connections between the northern and southern anticyclones weakened and diminshed in

size.

ADCP measurements during cruiseN2 confirmed SSHA observations, and established that currents

associated with the anticyclone located over DeSoto Canyon were along-isobath along the northern

edge of the canyon, while the flow of deep water was shoreward along the sides of the canyon and

in the bottom Ekman layer. Cool water penetrated closest to shore near the head of the canyon.

While cool water was not observed over SAIC's 100 m isobath moorings A or B in April, clear

evidence was found that onshore, near-bottom flow reached the 10m isobath at most stations west

of Cape San Blas prior to the N2 cruise in May (see Nowlin et cii. Figures 1H.5, 1H.8, and 1H.9).

Bottom water did not penetrate to these shallow depths at stations southeast of Cape San Blas. It is

of interest to note that the presence of cool bottom water on the innersheif west of Cape San Bias

occurred as much as a month before the first reports of mass mortalities in the region, and prior to

the time AVHRR imagery detected cool water on the surface.

Warm temperatures in spring, enhanced by fresh water from local river sources on the surface and

cool water near the bottom resulted in a stable water column with the strongest pycnocline west of

Cape San Blas and east of Mobile Bay in the region generally corresponding to the distribution

of depressed dissolved oxygen concentrations (see Nowiin et al. Figures 1H.11 and 1H.12).
449

Nowlin et al. observed that the distribution of fresh surface water in May occurred inshore on N2

transect lines 1 and 2 west of Moble Bay (see Nowlin et aL, Figure 1H.5), and offshore on transects

3-7, in the region south southeast of Mobile Bay - southwest of Cape San Blas. Local rivers were

suggested to be the source of fresh water observed at western, inshore stations, while the presence

of fresh water on the surface offshore, "could have been caused by nearshore upwelling moving

surface water offshore or by advection from the west due to the anticyclonic circulation over DeSoto

Canyon." (Nowlin et al. 1998). In early June, a cool event lasting several weeks was observed at

meteorological stations located in Mississippi Sound and at Dauphin Island. The presence of cool

water ('-5 °C) observed at these locations by Nowlin et al. occurred soon after peak discharges from

the Mississippi River, as noted earlier. The maximum eastward extent of the Mississippi River

plume occurs during eastward winds (Walker 1994), suggesting that the source of cool water

observed in June may have also had a riverine source.

Nowlin et al. reported transmissivity at 660 nm wavelength was at least 80 to greater than 90% in

nearshore bottom water from Pensacola to Tampa evidence that offshore water low in chlorophyll

upwelled onto the shallow shelf east of Mobile Bay. West of transect line 4, off Pensacola, percent

light transmission decreased inshore and toward the surface.

According to Nowlin et aL, nutrient concentrations appeared to be elevated at inner and midshelf

locations where cooler upwelled water was observed. High nitrate concentrations were associated

with depressed oxygen concentrations at these locations (see Nowlin et al. Figure 1 H. 13), and

provide evidence of the onshore movement of nutrient-rich bottom water.

DISCUSSION AND SPECULATION

The seasonal evolution of environmental features in northern portions of the NEGOM from spring

through mid-summer are, with some variation in timing due to interannual variation in climate and

ocean conditions, predictable sequelae of the sun's poleward progression. In late spring, alr and sea

surface temperatures begin a warming trend that continues through mid- to late August. A pycnocline

develops and strengthens with increasing surface temperatures and winter-spring discharges of fresh

water from rivers and estuaries. By early summer, water below the pycnocline is isolated from the

mixed layer, and oxygen replenishment occurs largely by diffusion as turbulent mixing decreases

with the late spring-summer reduction of frontal passages and strong winds. Prevailing spring and

summer winds in coastal regions of the NEGOM are northerly, easterly, southerly or nearly calm

(Blaha and Sturges 1981; SAIC 1997), depending on the period of record and distribution of stations

selected for analysis. Prevailing westerly winds (i.e., to the east), as observed through most of the

period from January through late July 1998, are uncommon in the NEGOM.

In addition to unusual winds, precipitation patterns during the first seven months of 1998 were

atypical with respect to the 104 year period of record. Above average volumes of fresh water entered

east-central portions of the NEGOM throughout winter, and a large, days-long "pulse" of fresh water

from heavy rains in coastal watersheds reached this region of the Gulf in mid-March. It is likely that

nutrient loading in shelf waters increased during the period of high river runoff and estuarmne

flushing. Rainfall ended after mid-March, and unusually warm, dry weather dominated eastern
450

portions of the NEGOM until late July. With increasing temperatures, the cessation of storms and

greatly diminished discharges of fresh water, a strong pycnocline may have developed in NEGOM

shelf waters in late March or April, a month or more earlier than the seasonal norm.

Unusual climatic conditions were temporally correlated with, but probably causally unrelated to

anticycionic ocean features in the NEGOM described by Nowlin et al. (1998). As described by these

authors, clockwise circulation and cool water upweiling were forced by an anticycione located over

DeSoto Canyon during the period of interest from April through July 1998. Nowlin et al.

demonstrated that widespread upwe!!ing occurred prior to their 5-16 May cruise, with the penetration

of cool, near-bottom water to, or possibly inshore of the 10 m isobath on much of the shelf between

Mississippi Sound and Cape San Bias. The maximum penetration of cool bottom water during the

first half of May and in mid-July occurred near the head of the DeSoto Canyon. Reports of unusually

cool water nearshore and observations of distressed or dead marine organisms suggest that pulses

of cool water also penetrated to innershelf depths after mid-May, in June and in early July.

Nowlin et al. (1998) presented clear evidence of upwelling prior to early May; however, AVHRR

satellite images of sea surface temperatures indicate that upwelled water did not reach the surface

in nearshore shelf waters until about 11-12 May, after which it was detected (with considerable

temporal and area! variation), between Mississippi Sound and the southern Big Bend region through

18-20 July. Remote sensing supported by observations of commercial divers suggests that upwelling

was strong and persistent west of Cape San Bias and east of Pensacola Bay, generally corresponding

to the region where mass mortalities occurred and ecological impacts were most pronounced.

Ecological conditions were less affected east and west of what appears to have been the central, or

core upweliing area.

Strong innersheif upwelling occurred prior to cruise N2 in May, several weeks before mass

mortalities were first reported. Because cause and effect relationships between upwelling and mass

mortalities are uncertain and of great interest, speculative, non-mutually exclusive explanations for

the weeks-long lag between upwelling and mass mortalities are offered. Caveats are assumed to be

givens. First, it is possible that dissolved oxygen concentrations in upwelled DeSoto Canyon water

were higher in April and mid-May than during the last two weeks of May. Dense concentrations of

the tropical, cool water-tolerant alga, Heterosiphonia cf. gibbesii (see Pakker et al. 1995) were not

observed until late May-early June, within the time frame of mass mortality events on reefs off

Panama City. The source of Heterosiphonia is not known, but a propagule ofsome size may have

been transported onto the shelf by anticylonic currents described earlier. According to Nowlin et al.

(in press), chlorophyll concentrations beneath the pycnocline were low (80 to >90% transmission

at 660 nm) suggesting that the algal population occupied and increased in the mixed layer, and that

its physiological tolerance to cool water was greater than that of the normal "June grass" bloom of

Cladophora, a warm water alga. As nutrients in the mixed layer were depleted by growth of the algal

bloom which co-occurred with blooms of non-toxic dinoflagellates and other phytoplankters, the

Heterosiphonia population began to die, sank beneath the pycnoclirie, and contributed to a positive

feedback loop of increasing BOD and decreasing dissolved oxygen concentrations. Evidence

supporting very low dissolved oxygen concentrations is weak, and based on one credible

measurement. On 1 July, National Marine Fisheries Service divers reported a strong thermocline at
451

4.5-7.5 m, in water 14 m deep in St. Andrew Pass. Visibility at the bottom was reduced to a few

meters by floe and rafts of what appeared to be green algae. At the surface and at 7.5 m depth,

respectively (the length of the Hydrolab cable), temperatures were 29.0 and 2 1.4° C; salinities were

32.8 and 35.3 psu; and dissolved oxygen concentrations were 5.91 and 0.37 mg Water

temperature at the bottom was 19°C. Hypoxic oxygen concentrations (2.0 mg1') were not

encountered by Nowlin et al., although concentrations near 3 mg11 were measured during cruise N2

in early May. Mass mortalities attributed to low dissolved oxygen concentrations also occurred after

cruise N2, suggesting that hypoxic or anoxic conditions also occurred after mid May. For this view

to have merit, it must be assumed that hypoxia or anoxia developed rapidly not oniy in the benthic

boundary layer, but a sufficient distance above the bottom to account for the vertical reach of wrecks

and reefs. Under a strong pycnocline it may be possible that respiration in resident benthic

communities, coupled with the consumption of oxygen by microbial decomposers, could have been

great enough rapidly to have lowered dissolved oxygen concentrations to levels stressful or fatal to

marine organisms.

A second speculation is coupled with the first. Elevated nutrient concentrations in upwelled water

were observed at inner and midshelf depths offshore St. Andrew Bay, Cboctawhatchee Bay and

Santa Rosa Sound, where organically rich sediments and high nutrient levels have been well

documented (SAIC 1997). It is possible that Hurricanes Allison, Erin and Opal, which passed over

these estuaries in 1995, translocated large amounts of their sediments to the shelf (see Isphording

et al. 1987). With the additional flushing of nutrients and organically-rich sediments during flood

conditions in mid-March 1998, chemical oxygen demand, in addition to an increased biological

oxygen demand associated with algal decomposition, may have consumed much of the oxygen from

upwelling water as it moved shoreward.

Other, somewhat less convoluted explanations are proposed. These suggest that: (1) Mass mortalities

may have occurred in April but at depths greater than those usually explored by divers. If so, the

question of what caused mass mortalities remains wanting. (2) Hypoxic (<2 mgl') or anoxic water

believed to be responsible for mass mortalities from mid-May through early July may not have

originated in DeSoto Canyon, but advected into the region from the west; or (3) Water from DeSoto

Canyon upwelled onto the shelf (but not to the surface) in April, where it remained as a relatively

cool bottom layer beneath a strong pycnocline. During succeeding weeks (until about mid-May)

dissolved oxygen in the relic watermass was gradually depleted as a result of high BOD/COD. It is

difficult to attribute mass mortalities to causes other than oxygen stress. Toxic dinoflagellates were

not present in abundance, and results of toxic screening by the Florida Marine Research Institute

were negative (FMRI pers. comm.).

Although many marine organisms died during the upwelling event, systematic sampling was not

possible, and neither the numbers of organisms nor the species involved can be known or

approximated with confidence. Divers tend to avoid reefs known to have suffered extensive

mortalities, and follow-on observations ofbenthic, reef-associated organisms, if made, are unknown

to the author. In late July, however, pelagic fishes in the vicinity of reefs were reported to appear

normal in abundance and diversity.
452

SUMMARY AND CONCLUSIONS

Atypical climatic conditions in portions of the NEGOM, including eastward winds and early

formation of a pycnocline were related to the 1997-1998 ENSO and atmospheric dynamic conditions

(ENSO-NP). Eastward and shoreward shelf currents and the upwelling of deep water from DeSoto

Canyon were attributable to a persistent anticyclone located over the canyon. Correlations but not

causation between climate and ocean conditions were found. Mass mortalities of pelagic and benthic

organisms in the Panama City-Destin region are attributed to putative hypoxic, or perhaps anoxic

conditions caused by a large biological oxygen demand. BOD was clearly exacerbated by a dense

algal population of a tropical, but cool water-tolerant species of red alga, Heterosiphonia cf. gibbesii.

Nutrient-rich sediments deposited on the shelf by floods in 1998 and by hurricanes in 1995 may also

have increased total oxygen demand. Correlations but not causation between cool water upwelling,

hypoxia, anoxia, and mass mortalities were found. The ecological consequences of dramatic, but

relatively short-term mass mortalities in populations of adult benthic and pelagic animals, and of

meroplankters recruiting to shelf habitats could not be adduced from the information available.

Maj or long-term consequences of the upwelling event are expected to be relatively minor

REFERENCES

Blaha, J. and W. Sturges. 1981. Evidence for wind-forced circulation in the Gulf of Mexico. J. Mar.

Res. 39(4):71 1-734.

Isphording, W.C., F.D. Imsand, and G.C. Flowers. 1987. Storm-related rejuvenation of a northern

Gulf of Mexico estuary. Trans. Gulf Coast Assoc. Geol. Soc. 37:357-370.

Muller-Karger, F. 1998. Remote sensing. U.S. Dept. Interior, Mineral. Manage. Serv., 18th Inform

Transfer Mtg.

Nowlin, W.D., Jr., A.E. Jochens, M.K. Howard, and S.F. DiMarco. 1998. Nearshore, bottom

properties over the northeastern shelves of the Gulf of Mexico as observed during early May

1998. U.S. Dept. Interior, Mineral. Manage. Serv., 18th Inform. Transfer Mtg. (in press).

Pakker, H., A.M. Breeman, W.F. P. van Reine, and C.van den Hoek. 1995. A comparative study of

temperature responses of Caribbean seaweeds from different biogeographic groups. J. Phycol.

31:499-507.

Purdue University. 1998. Image and map archive: upper air charts. Online. Internet. Available

<http://wxp.eas.purdue.edu/archive/eta init/> (et seq.).

Science Applications International Corporation. 1997. Northeastern Gulf of Mexico coastal and

marine ecosystemprogram: Data search and synthesis; synthesis report. U.S. Dept. Interior, U.S.

Geol. Surv., Biol. Resour. Div, USGS/BRD/CR-1997-005 and Minerals Manage. Serv., Gulf of

Mexico OCS Region, New Orleans, LA, OCS Study MMS 96-00 14, 313 p.
453

Science Applications International Corporation. 1998. DeSoto Canyon eddy intrusion study.

Statistical data products: set 4. April 1998 - August 1998. Tech. Rep. MMS Contract 1435-01-

96-CT-30825. Unpaginated.

Tanner, W.F. 1992. Natural environment. In: Atlas of Florida(E.A. Fernald andE.D. Purdum, eds.).

Inst. Sci. Public Affairs, Florida St. Univ., Univ. FL Press, pp 12-77.

U.S. Department of Commerce. 1998 c. Teleconnection patterns. Natl. Ocean. Atmos. Admin., Natl.

Weather Serv., Nat!. Environ. Satellite, Data Inform. Serv. Online. Internet. Available

<http.i/nic.Jb4.noaa.gov:80/data/teledoc/teleintro. html>

U.S. Department of Commerce. 1998 a. January and February, 1998: Warmest

and wettest on record. Natl. Ocean. Atmos. Admin.; Natl. Environ. Satellite, Data,

Inform. Serv.; NESDIS Press Release March 9, 1998. Online Internet. Available

<http://www. ncdc. noaa. go v/ol/climate/warmest. html>

U.S. Department of Commerce. 1998 b. Special climate summary 98/1: Atmospheric conditions

affecting the United States during April - June 1998. Natl. Ocean. Atmos. Admin., Natl. Weather

Serv., Natl. Centers Environ. Predict., Climate Predict. Center. Online. Internet. Available

<http://nicjb4. noaa. gov/products/specialsummaries/98_1/>

U.S. Department of Commerce. 1998 c. Special climate summary 98/2: Atmospheric conditions

affecting the United States during July and early August 1998. Natl. Ocean. Atmos. Admin.,

Natl. Weather Serv., Nat!. Centers Environ. Predict., Climate Predict. Center. Online Internet.

Available <http.//nic.Jb4. noaa.gov/products/specialsummaries/982/>

Walker, N.D. 1994. Satellite-based assessment of the Mississippi River discharge plume's spatial

structure and temporal variability. OCS Study MMS 94-0053. U.S. Dept. Interior, Minerals

Manage. Serv., Gulf of Mexico OCS Region, New Orleans, LA., 56 p.

Wolfe, S.H., J.A. Reidenauer and D.B. Means. 1988. An ecological characterization of the Florida

Panhandle. U.S. Fish Wildi. Serv. Biol. Rep. 88(12); Minerals Manage. Serv. OCS Study, MMS

88-0063, 277 p.

The author is a professor of biology at the University of West Florida with current research interests

in the mechanisms and ecological consequences of heavy metals accumulations by ascidian

tunicates; the pelagic ecology of post-hatchling sea turtles; and ecological processes in marine

ecosystems.
Introduction

Findings of the Gulf of Mexico Baseline and

Community Study

Helicopter Transportation in the Gulf of

Mexico

Downsizing the Operation Instead of the

Company

Coping with Uncertainty and Minimizing

Regret: Shifting the Emphasis in

Environmental Assessment

Panel Discussion

Conclusion: The Issues Identified

SESSION IJ

ISSUES FOR THE MILLENNIUM: DEFINING SOCIAL AND ECONOMIC

ISSUES FOR THE YEAR 2000 AND BEYOND

Co-Chairs: Dr. Claudia Rogers and Dr. Harry Luton

Date: December 10, 1998

Presentation Author/Affiliation

Dr. Claudia Rogers

Minerals Management Service

Gulf of Mexico OCS Region

Ms. Barbara Wallace

TechLaw, Inc., Bethesda, MD

Mr. Neill Osborne

Air Logistics

Mr. J.L. Rike

Rike Service, Inc.

Dr. Keith Storey

Mr. Mark Shrimpton

Community Resource Services Ltd.

Dr. Claudia Rogers

Minerals Management Service

Gulf of Mexico OCS Region

Dr. Claudia Rogers

Dr. Harry Luton

Minerals Management Service

Gulf of Mexico OCS Region

455
INTRODUCTION

Dr. Claudia Rogers

Minerals Management Service

Gulf of Mexico OCS Region

This session addressed social and economic issues for the year 2000 and beyond. It was divided into

two segments: the first featured panel members and their individual expertise, and the second

consisted of an open discussion among the experts. The presented a cogent and well-founded

identification of some of the factors facing residents, political leaders and policy-makers as they

attempt to deal effectively with oil and gas extraction activities.

Barbara Wallace, the first panel member, summarized the preliminary results of the MMS study she

is managing on oil/gas-related activities and their effects on coastal communities along the Gulf of

Mexico. She set the stage for the morning by examining trends and focusing on a few key issues that

she and her research team identified. Ms. Wallace told of such factors as the following: (1) changes

in how individuals learn a profession (from a relative and on-the-job training to more formal, highly

technical skill certification) and changes that better their worth on the market; (2) the importance of

world oil trends varies by geography and economies (the importance is high in Louisiana and Texas,

low in Mississippi and Alabama and lowest in Florida); (3) fluctuations in oil and gas prices and

employment levels discourage workers enough to warrant relocating their families and income

searches and excluding the future possibility of returning to "the oil patch" whenjobs are plentiful;

and (4) future MMS studies should combine both county-level evaluations with community-level

ethnography to overcome the barrier of aggregated numbers.

Neill Osborne traced the history of air transport and the changes it has undergone in response to oil

and gas extraction in the Gulf. He also discussed future trends he sees as affecting us in this part of

the country. He spoke of the sheer numbers of aircraft, from 130 in the early 1 970s to 600+ in 1983,

scattered over 20 onshore service bases along the Gulf of Mexico. From 1983 to 1990, the numbers

changed from 33 operators to 3 and from 600+ aircraft to about 350. As of 1997, there were 636

helicopters operating, indicating a re-strengthening of oil and gas extraction. And during that same

year, 1997, there were only 1.27 accidents per 100,000 hours in flight. Mr. Osborne had us consider

the future in terms of increasingly sophisticated GPS (global positioning system) tracking and

communication, aircraft which would be larger, faster, more costly and more safe, and aircraft

manufacturing following the oil industry example of globalized contracts.

3. L. Rike addressed the need to look for more reservoirs of oil and gas with smaller rigs, platforms

andlor ships as opposed to downsizing the companies. He also evaluated the future of oil and gas

activities in light of new technologies, price structures and regulations. Mr. Rike outlined his

strategic approach of making the oil or gas operation smaller, more responsive and more efficient

and cost effective. This would avoid the need to fire employees, only to try to re-hire them once

favorable conditions returned. He specified a number of technological developments which made

smaller operations more attractive and feasible - 3-D seismic, slim-hole drillings, hydraulic rigs,

457
458

progressive cavity pumps. He warned, too, that governmental regulations also must change to reflect

the new downsizing trend in operations.

Mark Shrimpton and Keith Storey completed this first potion of the session by looking at the onshore

implications of offshore development, from construction to operation, and how to recognize the

uncertainties involved and their effects at the community level. Dr. Storey directed our attention

away from the traditional emphasis of social impact assessment to the potentially affected

communities. He would have us look first to the goals or objectives of those communities and their

respective capacities to deal well with external changes. He also urged that the environmental impact

assessment process include different viewpoints of what should be evaluated, from the proponent's

perspective as well as the perspectives of the government and local residents. Mr. Shrimpton

reserved his remarks for the second segment of the session.

Dr. Claudia Rogers is an anthropologist with Minerals Management Service in the Gulf of Mexico

office charged with social and economic impact assessments. She and her colleague, Dr. Harry

Luton, also an anthropologist, develop and monitor social science research.

FINDINGS OF THE GULF OF MEXICO BASELINE AND COMMUNITY STUDY

Ms. Barbara Wallace

TechLaw, Inc., Bethesda, MD

In 1996, a team of economists, anthropologists, and a social historian embarked on a three-year study

to increase the understanding of Outer Continental Shelf (OCS) development impacts on Gulf of

Mexico (GOM) communities through the use of a regional trends analysis using secondary data

sources and examination of specific issues using field work in selected communities. The context

of the impacts in terms of the social history of the region was also to be explored. The study also set

out to use different methodological approaches to examine the economic and social impacts to

identify strengths and weaknesses of the approaches in answering some of the study questions.

The first year of the study was spent selecting the geographic units of study, including the field work

communities, identifying and selecting issues on which to focus the field work, and selecting the

variables for the regional trends analysis. The second year was spent actually undertaking the

research. Now that the research has been completed, we are in the process of completing the

analytical work for the study's report and the synthesis of the project pieces.
OVERVIEW OF THE APPROACH

Issue Selection

The issues on which the study focused were selected in a three-step process in which key issues were

identified in a literature review, and screened or filtered through pre-established issue selection

criteria, and then confirmed at a team meeting with MMS and the study's Scientific Review Board

(SRB). Four issues emerged from the issue selection process as areas for further research:

Demographic and economic change along the coast

Community histories

Labor processes

Education

Community Selection

The study areas were selected in a three-step process. First, a cluster analysis was used to identify

groups of similar counties/parishes based on variables from the Socioeconomic Baseline Study ofthe

Gulf of Mexico prepared for MMS by Louisiana State University. Eventually, the cluster analysis

identified eight groupings of counties/parishes from Florida to Texas. Then, expert opinion from

MMS, the research team, and the SRB was used to select five study counties/parishes from four of

the clusters. The five counties/parishes became the focus of the regional trends analysis. The field

work was conducted in six communities within these counties/parishes. The communities were

selected following scoping trips and using expert opinion from MMS, the research team, and the

SRB. The study areas and related counties/parishes and communities are shown in Table 13.1

Table 13.1. Study areas and related counties/parishes and communities.

459

Regional trends variables. The regional trends analysis focused on 55 variables selected after a

review of socioeconomic impact studies, consideration of data accessibility and projectresources,

and consultation with MMS and the SRB. The variables are grouped as population, economic, public

finance, and social.

Mobile J3ay Study Area South Louisiana Coastal flend Texas

Study Area Study Area

Baldwin County, AL Lafourche Parish, LA San Patricio County, TX

Gulf Shores Sebriever Ingleside

Mobile County, AL Terrebonne Parish, LA Mathis

Theodore Galliano
460

EMERGThtG FINDINGS

Two recurring themes from the regional trends analysis and the field work are highlighted below as

examples of high-level emerging findings.

Impacts from offshore oil and gas vary widely among the study area states, counties, and

communities. In terms of production, Louisiana and Texas exhibit substantial levels of OCS-based

extraction activities; the other study area states (Florida, Alabama, and Mississippi) do not. Louisiana

is the largest OCS oil and gas producer in the Gulf, but Texas is a bigger overall oil and gas

producer. Examination of the selected economic, population, and social variables show a similar

pattern the variables track somewhat with offshore oil and gas activities particularly in Louisiana

and Texas, but not in Florida, Alabama, and Mississippi. Of the study area states, counties, and

communities, offshore oil and gas is only important to the economies of Louisiana and Lafourche

and Terrebonne Parishes, and to a lesser degree for Texas and San Patricio County.

In terms of histories of the communities, there is variation in the factors that shaped them. While oil

and gas has been a part of the communities, it has not always been highly visible. One study

community where oil has had an important role is south Lafourche Parish where the story is one of

oil and fish. Throughout the historical progression of oil development from land to marsh to bay to

the outer continental shelf, local Cajuns have sought ways to articulate with and buffer against, the

industry. When the industry was booming, they put their generations-long knowledge of boats,

bayous, and open water into service for the oil industry. During the downturns, they could resume

traditional pursuits in the fisheries. In contrast, the other study communities were shaped largely by

non oil-related factors - for example, the location of a munitions dump in south Mobile, Alabama;

changes in agriculture in Mathis, Texas; the demise of sugar plantations in Schriever, Louisiana; and

leisure and servicing the leisure class in Gulf Shore, Alabama. There is actually an absence of

substantial historical, social, and economic impacts from OCS development in many of the areas we

examined, which reenforces findings of earlier studies that the oil and gas impacts vary among areas.

The effects of national policies and international geopolitics can be seen at the local level. GUM

oil and gas activities operate within the world context of energy production (the big picture) and

within the regional context (the little picture). The big picture often drives the little picture. For

example, GUM OCS crude and condensate prices track world oil prices and events affecting supplies

and prices. During the industry's early good times, outsiders came to fill available jobs. When oil

prices fell in the mid 1980s and there was a downturn in the industry in the Gulf, some GOM

workers left the south Louisiana area to follow oil jobs in Mexico, the North Sea, and Nigeria, some

who had migrated to the area because ofavailablej obs left, and others returned to traditional pursuits

in fisheries or patched together whatever jobs they could. In the recovery period in the mid-l990s,

there was some resistance to returning to the oil industry by those who had lived through the good

times and the downturn.

Local effects of national policies and international geopolitics can be seen in non-oil and gas activities as well. World War II brought huge sums of federal dollars and many military bases to the Gulf

Coast states. The effects of these policies can be seen in a number of ways in this study: the fluctua-
Barbara Wallace is a Project Director at TechLaw, Inc. (Bethesda, MD) and head of TechLaw's

marine economics practice. She has undertaken studies of OCS-related social and economic impacts

since 1984 and has completed studies for MMS in all of the OCS planning areas. Ms. Wallace holds

graduate degrees in urban planning and international development and an undergraduate degree in

sociology.

HELICOPTER TRANSPORTATION IN THE GULF OF MEXICO

Mr. Neill Osborne

Air Logistics

This paper describes the nature of helicopter transportation in the Gulf of Mexico as it relates to the

changing service industry. To effectively discuss the helicopter service business in support of

offshore oil and gas exploration and production it is important to provide a brief history of our

industry.

In 1946, a young man named Peter Wright departed the New Jersey offices of Helicopter Air

Transport to sell helicopter service to Oil Companies. Helicopter Air Transport was the first

commercial helicopter operator in the United States. Mr. Wright was able to convince Standard Oil

of California to try the helicopter. Through a geophysical contractor, the Robert H. Ray company of

Houston, Helicopter Air Transport was able to demonstrate to many in the seismic survey business

the capabilities of this aircraft. Mr. Wright and crew loaded anew Bell Helicopter 47B into a moving

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ting military population, particularly in San Patricio County; the use of tax-free industrial bonds to

attract industry to a closed military base in Mobile, Alabama; use of German prisoners of war as field

hands in the sugar fields to overcome war-induced labor shortages; the building of homeports and

the designation of the Naval Station-Ingleside as the Mine Warfare Capitol of the World; and the

impacts of the Servicemen's Readjustment Act (i.e., the G.I. Bill) on education and work.

IMPLICATIONS OF EMERGING FINDINGS FOR MMS

The initial findings may have implications for MMS in terms of

Resource allocation for further study of OCS social and economic impacts

Focusing future work on the most promising variables

Using insights gathered from field work to interpret some of the county-level economic and

social impacts

Understanding the contexts in which the oil and gas industry operate and the types and

interrelationships of impacts experienced

Recognizing that there is more to the GUM than the offshore oil industry
462

van and drove it to Houma, Louisiana. Houma must have seemed to be the end of the earth to the

crew from New Jersey. The inhospitable marshes of South Louisiana proved to be indicative of the

demanding physical locations that would justify the cost of using a helicopter.

Because of its unique capabilities, the helicopter piqued the interest of seismic surveyors. Seismic

survey and oil company personnel from around the world traveled to south Louisiana to look at this

new machine. This first mission trial in the marshes south of Houma was plagued with breakdowns

but when the aircraft was operational, it did much more work than the marsh buggy could do. In

those days the marsh buggies had big wheels that played havoc with the active fur trapping business.

The helicopter was much more acceptable to the trappers than ground vehicles that demolished the

marsh that provided their livelihood.

Although the helicopter demonstration in 1946 was a technical success, it wasa professional failure

because Helicopter Air Transport soon went bankrupt. But the concept of using a helicopter to

support oil exploration had been originated and would be reintroduced when Bell Helicopter set up

its own business to provide helicopter service for the seismic efforts of South Louisiana.

The early days of helicopter support was a difficult learning period for our industry's entrepreneurs

but also a very exciting time. The Bell 47 continued to be the aircraft of choice for seismic work as

it had the right combination of payload and cost.

When asked to make the short flight from the marshland to offshore, the helicopter was up to the

task. The aircraft special equipment consisted only of a "wet compass" for navigation and rubber

float pontoon landing gear for occasional water landingseither planned or unplanned. Frequently

during periods of reduced visibility and low clouds the pilot would head for the drilling rig using the

pilotage technique of time, distance and heading to find nothing but gulf water where there should

have been a rig tender vessel or drilling structure. Even though there were many challenges, the

reciprocating engine powered helicopter, traveling at 60-70 mph provided good service for those

early offshore drillers and producers. The Bell 47 continued to be the helicopter of choice until light

turbine engines were developed and became available to aircraft manufacturers. The total helicopter

fleet supporting the Gulf of Mexico offshore drilling and production operations grew to almost 100

of these sturdy, small Bell aircraft by the early to mid 1 960s. The French company, Aerospatiale,

introduced one of the first turbine powered helicopters used in the gulfthe Alloette. This aircraft,

with its new generation engine was noisy but had the advantage of flying at 90 mpha major

improvement in speed. It also offered a significant increase in payload, providing four passenger

seats instead of the two and three passengers the 47 could transport. It was, however, expensive to

maintain and operators found support for the aircraft less than acceptable as response time for

replacement parts and technical support from Europe was excessive. Because of its expense and

these support problems, the aircraft never became popular with Gulf users.

The helicopter industry as a whole was the benefactor of technology improvements developed for

our military in support of the Vietnam war. The Bell Huey became a mainstay for troop transport and

close-in helicopter gunship support in Vietnam. Very soon after the aircraft was developed for the

military it was offered to commercial users where it found wide acceptance in the Gulf of Mexico.
463

The civilian Bell 204, as it was named, would carry seven passengers and was ideally suited to

provide the transport type service which was required to support drilling rigs and production field

personnel crew change activity as offshore exploration and production continued to increase and

gradually move farther offshore. Only a few short years after the development of the 204, Bell

upgraded this aircraft to the Bell 205 with much better payload and passenger seatingup to 13 seats

and, depending on the distance of the flight, up to 2700 pounds of payload. This product

improvement was again primarily developed for the U.S. Military with the civilian market being only

an afterthought. But the Bell 205 was introduced to the Gulf Coast market in the mid-1960s. This

was excellent timing for Bell as offshore crews were increasing in size and the need for the

additional payload and speed was paramount to offshore users.

Another maj or military requirement developed for our country's Vietnam efforts playeda significant

part in improving helicopter transportation not only for Gulf Coast users, but also for all helicopter

users throughout the world. The Army needed to improve the capabilities of the aircraft flying

observation missions. Bids were solicited from several helicopter companies. Each new design in

the competition would be powered by the recently developed small, yet powerful gas turbine engine

capable of over 300 horsepower while weighing only 150 poundsa truly remarkable improvement

of the power vs. weight ratio, which is crucial to helicopter manufacturers and users. Hughes

Helicopters won the initial military contract and built thousands of the OH-6, Cayuse helicopters for

the Army and thousands more of the civilian variant Hughes 500 line for commercial and private

use. Although Bell and filler lost the military bid, both companies elected to produce a civilian

version of its product. Hiller's 1200 Series helicopter achieved limited success. However, the Bell

206 series of helicopters have become the most popular light helicopters ever produced.

By the early 1970s the Gulf Coast helicopter fleet totaled almost 130 aircraft and consisted of Bell

47's, 204's, 205's, 206's, Hughes 500's, Aerospatiale's Allouettes and the Sikorsky S-55 whichwas

powered by a radial designed, reciprocating engine. The 55 was a sturdy aircraft which carried six

to seven personnel at approximately 100 mph. The 55 provided many years of service to Gulf Coast

users beginning in the 50s, but never experienced wide acceptance as a transport aircraft due to its

speed and lower payload.

The early 1970s continued to see rapid growth in offshore exploration and production with

corresponding growth in helicopter demand. The German aircraft manufacturing company, MBB,

developed a 5-place twin engine helicopter using two lightweight Allison gas turbine engines.

Several oil companies accepted the additional operating costs of the aircraft for their offshore flights

because of the second engine and the BO-105 is still in service today. Bell Helicopters also

developed a twin engine variant of the 205 naming it the Bell 212.

Another significant development of the mid-1970s was the introduction of IFR or instrument flight

rule flying to the Gulf of Mexico. With the advent of IFR capable aircraft such as the Bell 212 and

the infrastructure and procedures in place to allow IFR flight, helicopter operators could offer to the

oil companies near all weather flight capability. With the frequent low ceilings and reduced visibility

conditions of the Gulf Coast the ability to fly IFR greatly increased the utilization oftransport sized

aircraft.
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Growth in offshore activity continued during the 1 970s and the Gulf Coast helicopter fleet reached

500 aircraft by late 1979. This growth continued into the 1980s until by 1983 over 600 helicopters

were engaged in offshore Gulf of Mexico flight activity. Thirty-three helicopter operators conducted

business from approximately 20 offshore support hubs from Corpus Christi, Texas to Mobile,

Alabama. But then, as now, the most productive finds and the bulk of offshore development and

helicopter requirement remain in the central gulf areas.

Several new helicopter types were introduced during this growth period including the Aerospatiale

AS-350 Astar, a six-place single engine machine and the AS-355 Twinstar a twin engine variant of

the same design. Additionally, the Aerospatiale 33 OJ Puma found a niche in the Gulf market. This

machine was capable of carrying 18 passengers at 120 kts airspeed but, of course, the cost for these

capabilities was considerable. Bell Helicopters introduced the 21 4SuperTransport to compete with

the Puma and other large helicopters. The 214ST also carried 18 passengers at 125 kts and boasted

a range of over 400 miles allowing it to frequently make flights to distant offshore locations without

the need to refuel. Bell also introduced a medium-size twin, the 222 which found limited acceptance

due to its mid sized design. Bell also re-engineered its successful twin engine 212 with a new rotor

system and increased its available horsepower, naming the new machine the 41 2it could fly faster

and carry more payload than the 212. Sikorsky introduced a sleek new aircraft, the S-76A, which

could carry 12 passengers at 150 mph. The S-76A was well received by the Gulf market and also the

corporate and air-medical markets.

It seemed to all in the offshore helicopter support business that paradise had been found. There was

plenty of work for helicopter operators and new, better, bigger and faster designs were on the horizon

for our use. But then, the bottom fell out.

During the bust years starting in the mid-1980s the competition for a shrinking market forced many

of the 33-helicopter service companies to sell out to their competition or to close their doors. By

1990 only a hand full of operators remained. The big three helicopter operators in the Gulf that did

survive were PHI, ERA and Air Logistics. Oil companies that operated their own fleet of offshore

helicopters were also affected by the slowdown and were forced to compete with operators for

helicopter service work to offset the expense of their helicopter flight departments. Pricing was

predatory and frequently below cost in the mistaken belief that if the customer could be retained,

even at a loss, future pricing could offset these loses. These pricing schemes led only to disaster.

The fleet of helicopters utilized by the Gulf of Mexico Oil and Gas Exploration and Production

Companies dropped drastically during this time period from 600 machines to less that 350. By the

time of Desert Storm in 1991, the helicopter service business had neared completion of the purge

caused by the severe downturn in the GOM market. In 1992 and 1993 business remained relatively

flat but then the combination of improvements in seismic technology, tax relief, improving oil prices

and increasing demand for oil and gas created new interest and activity offshore. By the mid-90s, to

support this surge in our market, new and used helicopters were once again acquired by the larger

operators to support the renewed demand plus new operators also entered the once prohibitive

offshore market. Today, over 25 companies operate helicopters in the Gulf of Mexico.
465

Aircraft upgrades have continued over the past several years. Sikorsky has improved the S-76 by

offering more powerful engines and improving other features of that aircraft. The S-76C model

offers better payload, range and single engine performance than the original S-76A. Eurocopter has

continually upgraded the Puma series of aircraft so that the recently introduced Super Puma Mark

II can carry 20 passengers with a range of 460 NM. This aircraft could see service in the Gulf in

support of deep-water activity.

Helicopter manufacturers were encouraged by the upturn in our market as well as demand for

helicopters in other markets such as military, logging, air-medical, corporate support and search and

rescue. Manufacturers initiated the design process for some new helicopters and accelerated those

already on the drawing boards.

In 1997, offshore helicopter activity rivaled that of the early 80s. Gulf of Mexico activity supported

utilization of 380 single engine helicopters, 114 light twin engine aircraft, 131 medium twin and 11

heavy twin engine helicopters for a total of 636 helicopters in service on the Gulf Coast. A

remarkable 3,759,642 passengers were transported during 471,513 flight hours and 1,705,629 flights.

To support this level of flight activity, each operator must have heliport bases near the oil company's

shore base facility. Aircraft receive nightly, routine maintenance at these bases. The base frequently

serves as the departure and arrival heliport for the crews working offshore as well as the operational

base with quarters for the pilots & maintenance technicians during their time at work. Each of the

large three operators have heliports similar to this Patterson facility near the shore base locations

utilized by Gulf Coast oil companies. Over sixty-heliport support bases are currently in operation

on the Gulf of Mexico Coastline.

Additionally, each operator must be able to provide fuel to their helicopters offshore with

strategically located refueling stations, typically, a two-thousand gallon fuel tank plus all required

filtration and pumping equipment. There are currently over 250 refueling points in service in the

Gulf of Mexico.

To provide maximum aircraft availability to production efforts, many Gulf Coast users require

helicopters to remain offshore each night. These aircraft must have nightly maintenance inspections

and frequently be rotated back to the helicopter operators support base for more extensive

maintenance or component replacement. Over 60 aircraft remain offshore each night in support of

production efforts.

Flight following is a responsibility that the operator must address. Each aircraft must be in contact

with company flight following facility at all times. Frequent updates of the aircraft's location,

destination and other pertinent information is a must to ensure rapid response in the event of an

emergency. Currently, the most accepted method of maintaining this contact with each aircraft is for

the operator to locate offshore radio sites on platforms or drill rigs which are then remoted back to

the shore by microwave phone lines. To provide seamless radio coverage, the offshore radio sites

must be within 75 miles of other company radio sites enabling the pilot to constantly be in
466

communications with his flight following base. At the present time, over 100 remote radios keep the

600 Gulf Coast helicopters in contact with their flight followers.

Accident data for 1997 reveals a total of six aircraft accidents for the year. An accident is defined

by the National Transportation Board as any event that occurs while the aircraft is in operation that

causes substantial damage to the aircraft or serious injury or death to an occupant. Of the six

accidents, there was one crew member fatality resulting from a mid-air collision and there was one

engine-related accident. A normal industry measurement for comparison of accidents is to develop

a rate per 100,000 flight hours. The 1997 Gulf of Mexico helicopter accident rate per 100,000 hours

was 1.27. This rate compares favorably to those rates experienced by other air transportation

businesses. For example, the accident rate per 100,000 hours for all commercial helicopter

operations in the US was 3.33 per 100,000 flight hours.

Most airlines utilize accidents per 100,000 departures as a comparative measure. The U.S. scheduled

airline accident rate for 100,000 departures was 0.44 while the GOM helicopter rate per 100,000

departures was 0.35. Clearly, Gulf of Mexico helicopter operators provided a commendable level

of safety for their passengers in 1997.

To forecast what the future of helicopter utilization and service may look like for the Gulf of Mexico

I must preface my predictions with a qualifier. Assuming favorable conditions, which include an

economic structure that allows helicopter operators the income to modernize their helicopter fleet

and services, the following possible changes may become reality.

Today's flight following system may be replaced with a GPS based, satellite transmitted two way

tracking and communication system. Studies are already underway that may pave the way for this

system. Numerous aircraft are currently being tracked through use of satellite communication of data

from the aircraft to a base station. Exact GPS position reports are transmitted each 30 seconds

allowing the operator and the oil company to know at any given time the location and status of the

aircraft. Each aircraft will most probably be equipped with a TCAS or Traffic Collision Avoidance

System. This onboard warning system will detect other aircraft that could be close enough to cause

a mid-air collision and alert the pilot to the hazard.

As deep-water exploration increases in the more distant portions of the Gulf, larger aircraft capable

of higher speeds will be required to support oil and gas efforts. Flight activity will more closely

resemble helicopter activity in the North Sea where long distance flights have been the norm for

many years. Larger platforms with accompanying increased personnel on these platforms will also

drive the need for larger aircraft.

Completely new designs which are planned for completion and introduction between the present and

the year 2000 that may be found in service to Gulfusers include Sikorsky's S-92, Eurocopter's EC155 and Bell 1-lelicopter's 609 Tilt-Rotor. Both of these designs represent state of the art

manufacturing techniques arid business partnering.
467

The S-92 will carry the Sikorsky nameplate, but in actuality, this aircraft manufacturing process is

a collaborative team effort. The aircraft is to be constructed in modules by aircraft manufacturing

companies throughout the world. Companies in Taiwan, Brazil, Spain, China and Japan as well as

Sikorsky in the U.S. will build various major components of the S-92 which will then be completed

by Sikorsky for the customer's specific mission. This aircraft will seat 19 offshore workers with a

range of 410 N.M. With auxiliary fuel tanks the aircraft will have a 700-mile range with a reduction

of payload. Like the Super Puma Mark II, this aircraft could see service in support of deep- water

activity.

Under new aircraft certification rules, all aircraft must meet even more stringent design safety

requirements than in the past. Major dynamic components such as the main rotor hub and yoke must

be designed with redundant load paths. Aircraft performance for transport aircraft such as the S-92

must assure single engine flight capability in all phases of flight to include the power intensive takeoff and landing segments.

Recently designed and now in production is the Europcopter, EC-135. This aircraft features the

newer fenestron for directional control which enhances safety by replacing the conventional tailrotor.

Eurocopter is also fmalizing plans for a new medium, transport sized aircraft which should be in

production by the year 2000. This aircraft will cruise at close to 170 mph while transporting 12

passengers up to 250 miles offshore without the need for refueling stops. The aircraft will be

equipped with state of the art avionics and navigation systems as well as an onboard Health and

Usage Monitoring System which continuously reports on the status of critical aircraft dynamic

systems and support systems. The 155 will also meet the new demanding performance standard that

will allow continued flight in any phase of flight with one engine inoperative. Redundant main

gearbox lubrication systems and a fail safe main rotor hub will also enhance the safety of this new

helicopter.

Another totally new design for vertical flight is the Bell Helicopter Tiltrotor aircraft. The concept

for this aircraft has existed for many years but development efforts stalled due to the cost to prove

the concept. Once again, our industry benefited from the design of an aircraft for the U.S. military.

Through efforts of the US Armed Forces Commanders, funds were allocated several years ago for

the development of an aircraft that could carry 20 or more combat troops into confined landing zones

but cruise to the LZ at much greater than traditional helicopter airspeeds. Bell Helicopter and the

Boeing Aircraft Company created ajoint venture to develop such an aircraft. The Bell Boeing V-22

Osprey is now being produced for the US Military. This twin engine tiltrotor aircraft will take off

vertically, transition the rotors from vertical flight positioning to forward flight which will enable

the aircraft to fly at speeds approaching 300 kts and then reconfigure to the vertical landing or

helicopter mode of flight for arrival. With the production of the Osprey well under way, Bell

announced two years ago the plan to build a smaller version of the aircraft for civilianuse. The Bell

609 Tiltrotor is designed to carry nine passengers and will transport offshore workers from Gulf

Coast heliports to locations some 200 N.M. offshore in less than an hour while achieving speeds

exceeding 270 kts.
468

All of these new designs will come with much higher price tags than the existing Gulf of Mexico

fleet of aircraft. This increased cost may well motivate oil companies to partner with other oil

companies and even helicopter operators to minimize their expense. Although some sharing of

helicopter assets has occurred over the last few years, it will be even more financially attractive to

Gulf Coast users in the future to develop cost sharing partners.

It can also be expected that alternative schedules for offshore personnel will be utilized to help offset

the increased cost of transportation for these workers to and from their offshore work site. By

transitioning from the more traditional seven-days-on and seven-days-off work schedule to a

fourteen-on and fourteen-off or a similar longer stay schedule, gulf users may significantly curb the

added expense of helicopter transportation.

As in life, the one constant in our industry is change. By the year 2000 we will have witnessed

helicopters and its uses mature along with the offshore, Gulf of Mexico exploration and production

efforts, from the pioneers like Igor Sikorsky and his first operational vertical flight aircraft to

technology that will produce a 300 mile per hour, all weather capable, satellite linked, state of the

art flying conference room.

Today, business for helicopter operators in the Gulf is good. The safety record of the companies who

operate helicopters in the Gulf of Mexico continues to be outstanding. New technologies that support

our business and new innovations in design will enable us to carry more passengers, fly farther and

fly faster. As long as the demand remains as it is today and as long as those who fly helicopters in

the Gulf and the companies who support those efforts continue as they do todaythe future of

helicopter transportation in the Gulf will be stable, dependable, safe and 'Plying to a high standard."

Mr. Osborne holds an Airline Transport Pilot license and has flown and managed helicopter

operations in support of Gulf of Mexico exploration, production and product transmission for

twenty-seven years. He currently serves as Vice President of Aviation for Air Logistics. He is

immediate past Chairman of the Helicopter Association International, which he still serves as

Director. Mr. Osborne also is Vice Chairman of the International Federation of Helicopter

Associations. Mr. Osborne attended The University of Texas at El Paso and has studied business

management at Penn State University.
DOWNSIZING THE OPERATION INSTEAD OF THE COMPANY

Mr. J.L. Rike,

Rike Service, Inc.

Regulators work under competing and often mutually contradictory constraints. Their political basis

prescribes a win-win: to increase domestic production, government revenues, company profit sheets,

local participation, and safety; arid to decrease foreign imports, cheating, monopoly power, pollution,

and impairment to ancillary uses of the same environment. Given these constraints, it is a miracle

that the regulators manage at all, and even more so if they can minimize their intrusiveness and

maximize their fairness. Although no regulated industry is enraptured with its regulators, everyone

in the oil industry who has worked internationally knows horror stories of how bad it can be, and

generally gives high marks to MMS.

The most unfortunate aspect of regulations is their tendency to become a self-fulfilling prophecy.

They start from a given historical situation and tweak it and channel it to meet the political

objectives. In the process, the previously accepted norm, with the required alternatives, becomes set

in concretethe regulations make it difficult to radically change the way we operate.

Accepted practices taken from history are no longer adequate to meet current and expected

conditions, and future optimal practices must differ considerably from the past. Achieving those

optimal practices, however, will require cooperation from the regulatory community.

PRESENT PRACTICE

Offshore, drilling is dominated by big rigs, whether on platforms, drill ships, or semi-submersibles.

The platforms are big as well, to accommodate the big drilling rigs. Constraints of the past have

forced this trend: a high risk of failure to find reserves forced attention on large reservoirs, which

require large platforms, which require large up-front investments, which also require large reservoirs.

We are trapped in a vicious circle. There is nothing wrong with large reservoirs; they are quite

profitable. The problem with the vicious circle is that it usually excludes consideration of small-tomedium reservoirs.

Within this scenario, only large derrick-type rigs could do the job. Using trebles instead of singles

cuts tripping time in half, and trip time dominates the time-to-TD equation for deeper wells. Large

reservoirs require large tubulars, which means large hook loads, and only derrick-type rigs can

handle them. And a large rig requires a large platform.

Subsea drilling is one part of the solution because it gets rid of some of the structures. Submerged

production systems alleviate that when they are truly well-to-pipeline systems, but these are

extremely expensive. The risk of capsizing on the drill-ship means using singles instead of trebles,

and slowing down drilling, which raises the expense. The semi-submersible solves that problem, but

it has higher cost still. And the recent developments in the deepwater environment have run up the

469
470

per-diem prices even higher than they were in the 80s. So, at least as currently practiced, only the

largest reservoirs can justify subsea operations.

Branching into new horizons, such as deepwater or Arctic environments, helps boost domestic

production, but they require very costly new technologies and a long time to learn to make them

affordable, so only large reservoirs can justify these new areas.

Realistically, we need to ask, how many "North Slopes" are left out there? The U.S. consumes about

a North Slope every year. How much oil is readily available in smaller reservoirs left untouched by

strategies that can focus on large reservoirs alone? How many cuttings on the ocean floor are

justified to reduce long payout, since big rig-and-platform systems require tremendous up-front

investments? And how much longer can we expect a population that is getting "greener" in outlook

by the day to leave those exemptions in place?

A CHANGED PICTURE

Technology advanced, industry evolved, and public opinion changed markedly since the current

strategy became the norm.

First and foremost, 3D seismic has had tremendous impact on drilling risk: the risk that you've

missed the high point on the structure, the risk that there is no true "trap" at all, and the risk that you

will meet big, nasty surprises. The surprises are still there, and always will be, but they have to be

much smaller now to escape detection.

EPA regulations have changed the way drilling cuttings are handled on land. With the

reclassification of these wastes as hazardous, the cost of disposal increasedvastlywe can no longer

just fill a pit and cover it over at the end of the job. Two strategies have evolved to help face this

challenge.

Slim hole drilling is one response. Volume is proportional to diameter squared, so drilling smaller

holes greatly reduces the volume of cuttings. At the same time, it reduces mud inventory arid its

disposal cost, and the smaller tubulars reduce hook loads. It was the first solution attempted precisely

because it is old wine in a new bottle: almost all the ancillary technology needed for completion and

production had already been developed thirty years ago.

The other response is to view cuttings as temporary residents at the surface. The cuttings are ground

up, made into a slurry, and injected just below the previous casing seat. Discarded mud is handled

as part of that slurry, doubling the value of the idea. At present, this can only be done on land

because of regulations on cement jobs offshore. There are always some cuttings left uninjected at

the end, so some cuttings still require disposal, but the total has been reduced by a factor of three to

five.

Workover costs offshore spurred the development of non-derrick rigs. The hydraulic rig, or snubbing

unit, was originally a piece of faliback safety equipment when a drilling rig took a big kick with
471

limited casing in the hole, but then it became associated with concentric workovers. Its ability to

work under pressure made it much easier and safer to use clean workover fluids, which in turn led

to higher productivity. Currently, hydraulic rigs can handle 9 5/8" pipe and hook loads up to

million lbs., and these numbers increase yearly. Boat, barge, and jack-up mounted units are also

readily available. Some operators have used them for deepening work for years, despite the fact that

they employ singles rather than trebles.

A related development is the coiled tubing unit, originally envisioned as a "hollow wireline."

Economic constraints on the North Slope created an economic incentive to use large OD coils. The

conversion of the progressive cavity pump into a hydraulic motor coupled with the easier bending

of thin-walled pipe was the foundation for short-radius horizontal drillingno other technology

could turn a corner that sharply. One rig has been constructed with the coil immediately above the

injector, so that the entire coil can be rotated slowly, thereby maintaining dynamic friction between

coiled tubing and the hole, rather than static friction. The objective is to be able to drill longer

horizontal sections before lock-up. Cost per-foot for drilling with coiled tubing has dropped sharply

as the industry has accumulated experience.

There is no reason why the hole drilled with coiled tubing has to be horizontal. Since the pipe is

continuous, there are no connections to slow trips, so its slower drilling rate is partially compensated

by its faster trip time on deeper holes. Currently, coiled tubing is available up to 6 5/8"OD. There

are boat and barge mounted units, but that's presently the support equipment for the reel, not the

injector assembly; with no ability to create a riser, it is not used as a subsea rig. However, smaller

diameter pipe will bend readily enough to run over a subsea flowline loop, so it can be used from

the central production platform in subsea wells equipped for TFL intervention.

On the North Slope, BP already uses these two rig types together to reuse exhausted boreholes: a

modified snubbing unit runs casing strings and a coiled-tubing unit drills short-radius horizontal

drain holes.

Other properties of these rigs, or of industry itself, work to their advantage. Regulation, lawsuits, and

insurance all push for lowering risk, and the snubbing unit is inherently safer technology than the

conventional rigit was originally devised to get the conventional rig out of trouble. Coiled tubing

and snubbing rigs use much smaller crews, so manpower and support costs are much lower. And

both rigs are designed to work under pressure, so drilling can proceed while underbalanced, whether

that is planned or unplanned, leading to faster drilling rates. Here again, the regulations as presently

formulated do not allow us to capture this advantage at present offshore, but it is becoming common

in land drilling (e.g., air drilling) and on offshore workover operations where MMS has given

permission.

The soft price of oil, cheaper in constant dollars than before the first OPEC price shock, means that

cheaper development methods are necessary for sheer survival, not just profit maintenance. These

small rigs have low mobilization costs, so there is little need to hold them when they are not in use.

We pay for them only when we use them, and scheduling is very flexible. Two and sometimes three

can be in operation at one time on the same platform, and these can share their auxiliary equipment,
472

further reducing costs. If used routinely for drilling, the order of slot usage can be optimized to

exploit this, getting the platform to full production much sooner than a conventional rig could. Since

the per-diem costs are much lower, total drilling costs are lower in spite of the extra time to TD on

each well.

Finally, the structure of the industry has changed. Partnerships and alliances have converted many

companies, at the far upstream end, into project-packaging outfits and financial conduits, so those

companies are mostly property portfolio-oriented. Their technological domination of the industry

is now mostly concentrated at the downstream end, on production, refining, and marketing, and on

mega-projects such as the recent deepwater development. This pushes the upstream risks onto

contractors, but provides for higher profits. Hence, research is more and more dominated by the

service companies and contractors, so new technological developments are rapidly shared.

PRESENT OFFSHORE STRATEGY

Part of these developments have been incorporated into our offshore routine. New areas and many

old ones are explored using 3D seismic methods. Some prospects get discarded, but exploratory

wells are drilled on the medium to mega-prospects to prove fluid content and feet of pay. Since these

are throwaway wells, they are already slim-hole, because it is cheaper and faster. They are made with

derrick type rigs because coring has not yet been adapted to the other rig types, and because the wells

require larger safety factors than needed for development wells.

These new proven reservoirs come in many sizes. The large and mega-reservoirs are consistent with

present methods that produced the vicious circle, and we are at home with it. The medium-sized

reservoirs are put off until oil prices go up. The small reservoirs are dismissed as uneconomic.

Why do we still stay in the vicious circle, with its big rigs and big structures? Part of the reason is

"that's the way we've always done it." Part of the reason is that regulations favor it at present.

THE DOWNSIZING VISION

For small-to-medium development drilling anywhere, consider the following vision. The basic

equipment includes a pile driver (sometimes), a large snubbing unit, a large coiled tubing unit,

slurrification and injection equipment, small tankage and inventory, a small crew, and conimensurate

crew support facilities. All drilling is done slim-hole with cuttings reinjection.

First, where soil conditions permit, a pile driver sets drive casing. Otherwise, a large snubbing unit

spuds the hole and sets the conductor. The rig then drills and sets surface casing, and possibly the

first intermediate casing. Then the coiled tubing unit drills the lower part of the hole, where trip time

becomes a bigger part of the time-to-depth equation. The snubbing unit sets all casing strings. Indeed, with a snubbing unit already over the hole, drill collars can be added for vertical drilling,

solving certain present coiled-tubing drilling problems. The final part of the hole is drilled vertically

or horizontally, as desired. The final completion can be done by either unit as desired, since some

operators will use coiled tubing as the production tubing.
473

Nothing in this scenario is incompatible with the offshore environment. Smaller platforms become

possible, since the rig system is small. Multiple wells can be drilled simultaneously, reducing even

more the payout time needed for the smaller platform. The cuttings storage systems for slurrification

will likely be on a barge or boat, so the excess not normally injected can be moved to another well

in progress; and with multiple wells being drilled simultaneously, even this is not a strict necessity.

So there are no hazardous wastes at the end of the job requiring disposal on land or at sea, and no

special purpose disposal wells need be provided.

Nothing in this vision is incompatible with a drillship, albeit one on a much smaller scale than any

seen to date. Without a derrick, the camber (maximum survivable roll of the ship) problem

disappears, so operations can continue in a wider range of sea states, and the per-diem cost will

surely be much lower. An additional bit of technology might be required if the hydraulic rig cannot

handle the riser diameter, but a mast could be raised for this operation. Risers are already handled

in singles, not trebles, so a fifty-foot mast-type derrick (as used on truck-mounted drilling rigs)

would be sufficient, and sea state limitations would only occur during riser assembly or disassembly.

PROBABLE EVOLUTION

Land drilling in the U.S. is dominated by many small and a few medium-sized reservoirs, because

139 years of exploration have reduced the stock of mega and large reservoirs (except in Arctic

environments) and seriously depleted the stock of medium-sized reservoirs. They also face more

stringent EPA regulations with respect to cuttings disposal. Land operators had to find cheaper ways

to exploit new fields, or fold. So all the technologies mentioned above are already in use, to one

extent or another, and cost per-foot has been dropping as each has become more common. All that

is missing is to put it all together as a coherent strategy.

It has been slow in coming because the per-diem cost of conventional land rigs is not so very

different from the smaller rigs, so the savings envisioned are far smaller than what can be achieved

in water locations. Water locations also provide mobility so that the low volumes of cuttings

remaining at the end can be transformed into zero volumes, by barging the leftovers to an active

reinjection site. As water locations begin to use these methods, the lower cost of becoming a player

will change the mix of operators there, shifting the balance toward more small-scale, local

participation.

Inland water locations will be first, partly because the roster of land and inland water operators are

very similarthey will be less afraid of the new paradigmand partly because EPA regulations are

the same, so operators feel the same regulatory pressures. As development drilling shifts to smaller

rig types, fewer inland waterways will need to be straightened or widened, and the ease of directional

drilling with steerable dowrthole motors on coiled tubing means fewer will need to be cut in the first

place. The benefit to Louisiana, besides revenue, will be less saltwater intrusion from the Gulf, less

coastal erosion, and more economic productivity from other sectors, such as fishing and tourism.

The state waters in the continental shelf have the same regulators as the nearby land, so this

technology will transfer there rapidly once established in inland waters. The savings will be greater,
474

however, because new structures can be downsized as well. The lower up-front investment will

translate into a wider range of reservoir sizes exploited.

Assume for a moment that OCS regulations evolved to be consistent with this technology. The first

OCS-area operations of this type will surely be in heavily played or exhausted areas, because OCS

areas face an additional fmancial hurdle, pipeline cost, which tends to force the step-out areas to stay

in the "vicious circle." But otherwise it will follow the state waters pattern. Aswater depth increases,

the reduction in platform cost becomes more and more dramatic, however, and the widening of

reservoir sizes exploited will be even more dramatic.

Areas of the OCS more suited to subsea production face an additional delay, the development of the

mini-drillship discussed earlier. So the methods will have to become quite common in the platform

areas before the drilling companies will be willing to take the risk involved in new ship designs,

particularly if the price of oil stays soft. But the only technological hurdle is the riser-handling

system, either a "large-jaws" hydraulic rig or a small mast-type derrick. So the major risk is that the

first mini-drilisbips will be underutilized, which will result in a delay, and not a barrier to entry. The

mini-drillship will likely be three to seven times cheaper to construct than a conventional drill ship,

so the delay should not be all that long.

So the technology will move from land to inland waters to near-coastal areas to OCS platform areas

to subsea areas, the way oil technology has always moved. But only if we grant the assumption that

the regulation from MMS and other agencies evolves to embrace, perhaps even foster these methods.

As regulators, you can say, "No," and we pursue other visions. Possibly you feel safety and stability

is enhanced when only the largest players can enter the game. Possibly you feel that a few large

structures are easier to regulate than many smaller structures. Possibly you feel that enhanced

domestic production, by exploiting the small-to-medium reservoirs presently ignored, is not a

significant part of your charge. Or maybe you feel that cuttings discharge to the ocean floor is a

minor consideration, perhaps because you feel the green tide in public opinion is ebbing rather than

growing.

Or you can become excited about the dream, change the regulations overnight (hoping thereby to

push us quickly into the vision), and perhaps create as many future problems as you solve.

Or you can study it carefully, identifi your concemsfor safety, environment, government revenues,

etc.and tell the industry exactly what we need to show, and exactly what standards of proof you

will demand, before the regulations can be changed to embrace this vision. You can become part of

the dynamic process that ensures that the strategies and equipment employed provide broad benefits

to our nation, and not simply serve the god of cost control.

This vision will make it to the state watersthe industry has been groping toward it for many years.

Whether it strays one inch past the three-mile limit depends a great deal on whether MMS is proactive or reactive.
475

Movement in this direction from a regulatory standpoint is currently visible. New thinking about

well control training to focus on objectives rather than specific items to be taught is in the right

direction. Other moves by MMS to regulate by performance rather than specification will allow the

needed changes to occur faster.

Or you can study it carefully, identify your concernsfor safety, environment, government revenues,

etc.and tell the industry exactly what we need to show, and exactly what standards of proof you

will demand, before the regulations can be changed to embrace this vision. You can become part of

the dynamic process that ensures that the strategies and equipment employed provide broad benefits

to our nation, and not simply serve the god of cost control.

This vision will make it to the state watersthe industry has been groping toward it for many years.

Whether it strays one inch past the three-mile limit depends a great deal on whether MMS is

proactive or reactive.

Movement in this direction from a regulatory standpoint is currently visible. New thinking about

well control training to focus on objectives rather than specific items to be taught is in the right

direction. Other moves by MMS to regulate by performance rather than specification will allow the

needed changes to occur faster.

J.L. Rike is chairman and CEO of Rike Service, mc, and has spent 49 years in the petroleum

industry, including 22 years with Exxon (Humble) followed by 27 years as a worldwide consultant

and trainer. He has worked in drilling, production, unitization, reservoir analysis, completion and

workover design, development engineering, and training in locations all over the United States,

onshore and offshore, Canada, Central and South America, Africa, Middle East, North Sea, Far East,

Russia and Eastern Europe. J. L. Rike has played key roles in the development of new completion

concepts, directional perforators, sand control, coiled tubing rigs, well control in drilling and

workover, concentric tubing workover and completion operations, and advanced offshore completion

practices. He also has authored patents and papers on these new developments, as well as cementing,

perforating, wireline operations, workover economics, and worldwide industry practices.
476

COPING WITH UNCERTAINTY AND MINIMIZING REGRET: SHIFTING THE

EMPHASIS IN ENVIRONMENTAL ASSESSMENT

Dr. Keith Storey

Mr. Mark Shrimpton

Community Resource Services Ltd.

INTRODUCTION

Change, complexity, uncertainty and conflict play fundamental roles in resource and environmental

management. These elements create opportunities as well as problems for analysts, managers and

others, but a key challenge is to recognize their importance and determine how to function in their

presence. The focus of this paper is that of uncertainty and how it might best be addressed in the

context of planning for the social and economic consequences of offshore petroleum activity.

Our understanding of biophysical systems, of human societies, or of the interactions between natural

and social systems is at best incomplete and often imperfect. We are aware that conditions and

circumstances in the future could well change, yet decisions have to be made because it is not

realistic to wait until we develop the level of understandingwe would like to have before committing

to a given path of action. Given the realities of change, complexity and uncertainty, environmental

and resource managers are increasingly looking at approaches which allow for adaptation which

accept that we should learn from experiences, both good and bad (Mitchell, 17).

In this regard the thesis of this paper is that the utility of socio-economic impact assessment (SEIA)

can be improved by shifting the current emphasis on prediction to focus on (i) minimizing regret by

acknowledging the potential for inaccuracy of such predictions; (ii) maximizing flexibility by

designing and using appropriate impact management approaches; and (iii) maximizing learning

through appropriate monitoring and auditing procedures. This isseen as being particularly important

and valuable in respect of the offshore petroleum industry given the high levels of uncertainty that

typically characterize its activities.

THE ROLE AND IMPORTANCE OF PREDICTION

In many respects we understand very little about the ways in which social and economic systems work. As a consequence we are generally poor at predicting, with any degree of accuracy, the

impacts of major resource development activities on those systems. For this reason the current

approach to environmental assessment which emphasizes impact prediction, rather than impact

management, may not be in the best interests of those whom the assessment exercise is designed to

serve.

The design of mechanisms to manage the social and economic outcomes of projects, programs or policies are as, if not more, important than the predictions themselves. If assessment predictions are

erroneous, then actions based upon them are likely to be inappropriate or inadequate. Where
477

outcomes are uncertain, the alternative is to put in place mechanisms that encourage review and

revision of predictions and assessment conclusions, and which permit flexibility in the ability to

respond to changing conditions. A pragmatic, management-oriented approach towards socioeconomic assessment is likely to have greater utility than one which seeks to refine and improve

predictive capabilities.

If the primary role of SEIAs is to facilitate decision-making, then impact prediction is a necessary

stage in that process, but it should not be considered an end in itself. The traditional focus of

assessments on project approval and predictive technique often seems to forget that the essential

purpose of impact assessment is to help those likely to be affected to "be prepared," to minimize the

possibility of the unexpected occurring and to address the potential consequences of the expected

outcomes. Impact prediction may, in fact, play only a minor role in being prepared.

PREDICTION DIFFICULTIES AND MANAGEMENT APPROACHES:

HIBERNIA CASE STUDY

The construction of the production platform for the Hibernia offshore oil project on the Grand Banks

east of Newfoundland illustrates the difficulties of accurately predicting activity levels and welldesigned management approaches can overcome this.

Hibernia, Newfoundland's first commercial offshore oil field, was discovered in 1979. Current

estimates put recoverable reserves at 666 million barrels with a planned peak production of 150,000

barrels per day. The field is 315 km east-south-east of St. John's, the provincial capital, in the

relatively shallow (80 m) but seasonally ice-infested waters of the Grand Banks. The production

platform is a fixed, concrete, gravity-base system (GBS) design, adopted, in part, as the result of

pressure from the provincial government which wanted a project that would generate large amounts

of work in a province with very high unemployment levels. The GBS and one of the five main

topsides modules, plus a number of smaller components, were constructed at a greenfield site at Bull

Arm, Newfoundland. Other modules were built in South Korea and Italy and shipped to Bull Aim

for assembly and eventual mating of the topsides with the base. The completed platform was towed

to the field in May 1997 and first oil was produced in November 1997.

Table 1 J.2 illustrates expected and actual labor demand from project initiation to peak activity in

1995. As is often typical of such projects, actual labor requirements proved far different than

expected. The "errors" in part resulted from a project delay resulting from the 1992 pull-out of Gulf

Canada and from design problems and revisions. The significance of these predictive "errors" was

not so much in the potential implications for labor supply but rather the implications of

accommodating that labor in a rural area where there was little rental accommodation.

To avoid "swamping" local communities with a major influx of labor a work camp was established

for workers commuting beyond a 50-mile radius. This approach effectively "insulated" local

communities from excessive demands on services and infrastructure. In fact, by 1994 only 77

workers, or 2.5% of the workforce, together with 46 spouses and 56 children, had moved into the

area as a result of the project (Newfoundland 1994).
478

The use of the camp also allowed a rapid response when labor demands increased. Table 1J.3

illustrates the differences between predicted and actual numbers housed on site over the 1990-1995

period. The camp was originally designed to accommodate 1,500 workers, but this was initially

increased to 3,000 and subsequently a further 480 rooms were added. In 1995, demand for

accommodation onsite did exceed supply, causing some local rent inflation. However, this proved

to be a relatively short-term problem.

Table 1J.2.Predicted and Actual Employment Levels, Bull Arm Construction Site, 1990-1995.

Sources: Mobil Oil Canada, Ltd. 1985; HCSEMC 1990-1995.

This case study indicates that predictive accuracy of project outcomes is more likely to result from

luck than inspired modelling techniques. However, it also suggests this may not be of primary

importance. What is important is whether the impact predictions per se prove to be correct, but

whether what was wanted from the project was actually achieved. In the Hibernia case, a primary

impact management objectiveminimizing community disruptionwas achieved thanks to the

implementation of an appropriate management strategy.

REQUIREMENTS FOR A MANAGEMENT-ORIENTED APPROACH TO SEJA

The Hibernia case study also serves to illustrate a number of aspects of, and trends in, SEJA in

Canada. First, the assessment was project-based (rather than being concerned with a program or

policy) and had a strong focus on community effects with, not least, a concentration of effort on

trying to predict the consequences the project would have for a small number of geographic "impact

areas." Second, over the extended course of the assessment (while work on it started in 1981, the

SEIA was not submitted for review until 1985 and approved in 1986) there was a slow shift way

from the formal goal ofproject approval towards an assessment exercise that could contribute to the

management ofproj ect effects. This was driven by an expectation, fully-realized, that the uncertainty

that is characteristic of the offshore petroleum industry in general, and large construction projects

in particular, would rapidly make impact predictions redundant.

We believe that the experience with Hibemia and other such assessments points towards a need for

more management-oriented approaches to SEIA. In particular, we think it shows a need to use: (i)

a scoping of potential impacts which focuses on those which can usefully contribute to management;

(ii) assessment approaches which eschew prediction of the unknown (and in many cases

unknowable) in favor of capacity-based evaluations of the known; and (iii) a monitoring of socioYear 1990 1991 1992 1993 1994 1995

Predicted 250 850 1155 1465 2265 3600

Actual 116 972 898 3060 4019 5779
479

economic measures that contributes to the management effort. The rest of this section discusses

further each of these requirements.

THE SCOPING OF COMMUNITY EFFECTS

Progress has been made from early compendious assessments which sought to predict the effects of

projects on virtually all significant social or economic phenomena. It has been recognized that this

approach results in there being very limited and ineffective analysis of the effects on a very large

number of things. There has, in response to this, been a growth in the use of scoping exercises which

seek to focus the assessment effort on a subset of topics that past research, key informants and

professional knowledge indicate may be subject to "significant" effects. However, the scoping effort

usually fails to move beyond this identification of topics of concern to asking the question: "so

what?" and, in particular, an identification of the goals and objectives that the host communities

want to achieve.

CAPACITY-BASED ASSESSMENTS

Most assessments are "source-demand" driven; that is, a certain level of activity associated with a

project or "source" will generate a particular level of "demand" on local infrastructure, services, etc.

However, as discussed above, predictions of activity levels are often incorrect with obvious

implications for any proj ected consequences and responses. Where impacts are spatially concentrated

and the types of impacts known, an alternative approach is to focus on the "capacities" of those

components of the socio-economic system which are on the receiving end of the project outcomes.

An example illustrates this approach. A company proposes to build a refinery in a Newfoundland

community which has a current population of 7,000. It is expected that direct refinery employment

will be in the order of 900 workers. Skill levels required and local labor market characteristics

suggest that only some of the required workers can be provided from the local area. Non-local hires

have the option of moving to the community where the plant is located or commuting there on a

daily basis. The community is anxious to know how to respond and, in particular, whether or not

there is likely to be a significant demand for local housing.

The predictive model suggests that the population change through in-migration would likely be in

the range of 900 to 1,650, leading to a requirement for 374-593 housing units. Only low confidence

levels could be attached to these projections. However, study of the local housing market showed

that 50-60 dwellings were already available, while vacant serviced land would permit the

construction of another 300 units. While there was no guarantee that the market would respond

quickly to demands, it was concluded that there was sufficient capacity in the system to adequately

respond to the range of potential demands suggested by the predictive "source-demand" model. But,

in a contrasting example, analysis of the local water supply system indicated that it was already being

utilized beyond its design capacity, and that any new demand would exacerbate this problem. Such

analyses allow the planner or decision-maker to determine where capacity thresholds are exceeded

and system bottlenecks may arise, while reducing the dependence on "spuriously accurate"

predictions in which there is little confidence.
480

MONITORING AND AUDITING

If effective management is to be realised, then monitoring and auditing of outcomes provides an

essential feedback function. However, if this is to be useful, monitoring and auditing must focus on

the "achievement of desired objectives" rather than on "prediction verification," as is too often the

case. The limitations of the latter approach are illustrated by an example.

Examination of 143 socio-economic predictions in the Hibernia assessment (Mobil 1985) found that

only 86 were "suitable" for audit.1 However, of these 67 could not be verified as there were no

monitoring data, and for a further lithe data were inadequate. Of the remaining 8 "auditable"

predictions, 6 proved to be significantly wrong (Locke and Storey 1997). Thistype of audit fails both

to adequately demonstrate the accuracy of the assessment and to reflect the reality of the situation.

In fact, expenditure and employment levels exceeded the proponent's commitments and the

anticipated negative outcomes either did not occur or were significantly less than many intervenors

had feared when the assessment was reviewed.

Monitoring and auditing is often rarely done and when it is, it is rarely done well. This results in

what Sadler (129) describes as the "paradox of EIA" where the absence of follow-up precludes

any opportunity to learn from project experience, inhibiting both project management and the

advancement of impact assessment. By focusing monitoring and auditing on desired objectives rather

than prediction verification the utility of the EIA process could be significantly increased.

CONCLUSIONS

Since the formal adoption of EJA in the 1 970s the process has evolved significantly, albeit in a

piecemeal fashion. From an early concern with assessment methods, attention first shifted to

screening and scoping, the "front end" of the process, to help focus assessments. More recently

increasing emphasis has been given to the "back end" of EIA - impact management and follow-up

through monitoring and auditing. This reflects the greater role of EIA as a management rather than

simply a decision-making tool. However, if it is to be successful in this role then the design of

assessment procedures needs to be rethought. Monitoring and auditing should not be independent

of and subsequent to the assessment phase. Rather the desired objectives of the project, program or

policy in question should provide the basis for the follow-up program design which in turn should

influence what is assessed and how. By focusing on desired outcomes we may perhaps shift the

emphasis of assessment away from prediction and more towards management.

REFERENCES

Buckley, R. 1991. Perspectives in environmental planning New York, New York: Springer-Verlag.

Includes predictions that were sufficiently detailed and precise, still relevant and had occurred.
481

CMHC (1992-1996). Clarenville-Shoal Harbour house price survey. Canada Mortgage and Housing

Corporation Semi Annual Reports. St. John's, Nfid.: CMHC

HCSEMC 1990-1995. Hibernia project employment and work camp data. In Socio-economic review

Hibernia development project, Quarterly Reports. St. Joim' s, Nfid: Hibernia Construction Sites

Environmental Management Committee.

Locke, J. C. and K. Storey. 1997. Socio-economic assessment auditing: A Hibernia case study. In

A. J. Sinclair, ed. Canadian Environmental Assessment in Transition. Waterloo, Ont.: University

of Waterloo. 157-192.

Mitchell, B. 1997. Resource and Environmental Management. Harlow, Essex: Addison Wesley

Longman.

Mobil.1985. The Hibernia environmental impact statement. St. John's, Nfld.: Mobil Oil Canada,

Ltd.

Newfoundland. 1994. Demographic impact of the Hibernia development in the Bull Arm impact

area. St. John's, Nfid: Newfoundland Statistics Agency..

Sadler, B. 1988. The evaluation of assessment: Post-EIS research and process development. In P.

Wathem (ed.) Environmental impact assessment: Theory and practice. London: Unwin Hyman.

129-142.

Keith Storey is a principal of Community Resource Services Ltd., a socio-economic consulting

company he and Mark Shrimpton established in 1984, and a Professor of Geography at Memorial

University in St. John's, Newfoundland, Canada. His areas of interest are in socio-economic impact

assessment and management of maj or resource development projects. Dr. Storey received his B .A.

in geography from the University of Leicester in England, his M.A. from Simon Fraser University

and his Ph.. from the University of Western Ontario in Canada.

Mark Shrimpton, a principal of Community Resource Services Ltd., has over twenty years of

experience of petroleum-related research, primarily in the fields of resource development assessment,

planning, management and monitoring, for clients in the oil industry, governments and community

groups. Mark has a B.A. in geography from the University of Reading, England, and an M.A. in

geography from Memorial University of Newfoundland, where he holds the honorary position of

Adjunct Associate Professor.
482

PANEL DISCUSSION

Dr. Claudia Rogers

Minerals Management Service

Gulf of Mexico OCS Region

Mr. Shrimpton began this segment of the session with an overview of social trends in the oil and gas

industry, from technology to economics to business practices, and howthey can be understood in the

framework of impact assessment. He called our attention to the massive projects currently operating

or under construction, projects such as Hibernia in hazardous waters off Newfoundland and Mars

in deep water in the Gulf of Mexico. These are indicative of the trend toward retrenchment of larger

companies, the pooling of capital resources, and the increased globalization of manufacturing,

administration and finance of such large projects.

On the labor side of that same equation, there are only a small number of skilled, technically-trained

workers. These significant labor shortages have resulted in an international labor force comprised

of individuals from many countries brought together to work on one project or platform. The

implications of these trends for valid social impact assessments is to "de-problematize" the oil

industry, analyzing it in terms of its component parts rather than its complex, international whole.

De-problematizing also means properly addressing oil companies' increased attention to and

investment in their workers and beneficial effects on local communities.

Other panel members expanded the discussion to consider additional factors of the implications of

large-scale mergers such as Exxon and Mobil at the local level.

How are business decisions made regarding, say, the selection of support bases?

How do local business owners plan for or respond to decisions beyond their influence or control?

What community characteristics are more or less sensitive to external forces?

What part does the state political structure play on how a local area is affected by oil and gas

activities?

Given the future need for a highly skilled, university-trained workforce, where can

companies recruit such people?

This need for highly skilled workers is particularlytrue in the aviation field. When the U.S. military

was extensive and active throughout the world, companies had a ready supply of technicians and

pilots who were experienced, licensed and well-trained. That is no longer the case.

If merging companies continue to look principally to profits as motive for action, then research will

suffer and be focused on profit or market-based utility and questions of "what else is there" rather

than "what else is possible." Current extraction projects also leave companies vulnerable to terrorism

and massive projects even more so. Witness the offshore security precautions in the North Sea and
483

the fact that resource management now includes conflict management as well. Conflict must be

addressed at different levels, from local residents to environmental purists.

Dr. Claudia Rogers is an anthropologist with Minerals Management Service in the Gulf of Mexico

office charged with social and economic impact assessments. She and her colleague, Dr. Harry

Luton, also an anthropologist, develop and monitor social science research.

CONCLUSION: THE ISSUES IDENTIFIED

Dr. Claudia Rogers

Dr. Harry Luton

Minerals Management Service

Gulf of Mexico OCS Region

Those present readily agreed on a few key, overarching themes:

Oil and gas extraction is so complex that issues will change in number, scope and intensity.

The industry is not monolithic; it is global with a multiplicity of cross-cutting ties which can

also be competitive.

Given the complexity of oil and gas activities, construction, transportation and operations

become even more significant.

Technological changes in every phase of the oil and gas-related activity, suchas air, sea and

land transportation, directly effect costs of extraction.

Increased costs change the use of capital, leading to more partherships, from helicopter

companies and other supporting services, e.g., the Edison-Chouest "one-stop shopping"

center at Port Fourchon, Louisiana, to the partnerships formed whenmergers occur.

Uncertainty is also a given, due to the volatility of oil and gas, a volatility which local

communities cannot control.

The success of the oil and gas industry is due and will continue to be due in major part to its

adaptability to changing physical environments, labor forces, community demands and

economics.
484

Dr. Claudia Rogers is an anthropologist with Minerals Management Service in the Gulf of Mexico office charged with social and economic impact assessments. She and her colleague, Dr. Harry

Luton, also an anthropologist, develop and monitor social science research.

Dr. Harry Luton is an anthropologist with Minerals Management Service in the Gulf of Mexico

office. He and his colleague, Dr. Claudia Rogers, also an anthropologist, develop and monitor social science research.
Behavioral Responses of Marine Mammals

to Acoustic Disturbance

Document Not Submitted

Acoustic- Pressure Wave Effects on Sea

Turtles

Acoustic/Explosive Effects on Marine

Mammals

Document Not Submitted

SESSION 2G

ACOUSTIC/PRESSURE WAVE EFFECTS ON MARINE MAMMALS

AND SEA TURTLES, PART II

Co-Chairs: Dr. William Lang and Ms. Colleen Benner

Date: December 10, 1998

Presentation Author/Affiliation

485

Dr. W. John Richardson

LGL Ltd., Environmental Research Associates

Dr. Molly Lutcavage

New England Aquarium

Dr. Darlene Ketten

Woods Hole Oceanographic Institution
ACOUSTIC- PRESSURE WAVE EFFECTS ON SEA TURTLES

Dr. Molly Lutcavage

New England Aquarium

INTRODUCTION

In July 1998, a juvenile loggerhead sea turtle was killed during explosive platform removal of a

caisson in the Matagorda Island area. The turtle surfaced a few yards from the caisson four minutes

after denotation of two 50-lb Comp 13 charges and died during airlift to veterinary facilities. The

loggerhead's carapace was cracked along its entire dorsal margin, and its lungs contained pooled

blood and foam in the airways. Death was attributed to liver hemorrhage. In over 11 years of

monitoring surveys conducted by the NMFS-offshore industry sea turtle and porpoise observer

program (Gitschlag et al. 1997) this was the most recent of documented impacts, which included

three mortalities and two nonlethal injuries (G. Gitschlag pers. comm.). But since detonation was

officially cleared following the required pre-denotation surveys (John J. Kenny pers. comm.) it also

emphasizes the fact that the observer system may occasionally fail to detect submerged turtles. This

unsatisfactory outcome does not necessarily reflect upon the failure of monitoring efforts but

highlights the fact that sea turtle breath hold diving capabilities and behavior are wide ranging and

not easily predicted (Lutcavage and Lutz 1997).

Except for the very small number of direct observations on dead or injured animals, there is very

little known about the harmful effects of underwater explosions on sea turtles. Likewise, we have

virtually no information on the impacts of seismic operations on sea turtle physiology or behavior.

Extensive data on these subjects simply do not exist because laboratory and field studies are lacking.

In spite of this data gap, we can nonetheless review aspects of the sea turtle's functional anatomy,

physiology, and life style that may be impacted by offshore oil and gas exploration activities. With

this information and documented case studies in mind, informed decision making and planning may

proceed with some confidence that harm to sea turtles can be minimized

POSSIBLE IMPACTS OF EXPLOSIVE PLATFORM REMOVALS AND

SEISMIC ACTIVITY ON SEA TURTLES

In the publication "Guide to the Effects of Underwater Shock Waves on Arctic Marine Mammals

and Fish," S.H. Hill (1978) interpreted the effects of underwater shock waves on vertebrate animals

documented in experimental studies undertaken by the Lovelace Foundation and Dept. of Defense

(e.g. Yelverton 1973). These studies used terrestrial animals and fish as subjects. Hill's review, and

others examining the same data sets (e.g. Goertner 1982) provide a point of reference for considering

the possible physiological damage to sea turtles and other aquatic animals from underwater pressure

waves. Damage predictions from the Lovelace Foundation studies were based on actual trials and

modeling of physical parameters of explosions and how they would impact highly simplified and

idealized animal body compartments. Conclusions were that the primary sites of damage are the

lungs and hollow organs, which comprise the major tissue-gas phase interfaces in the vertebrate

487
488

body. In general, immediate damage occurs from concussive effects of the pressure impulse, and

major insults may include hemorrhage and gas emboli caused by air and gas in capillary beds which

can then lodge in the lungs, heart, and brain. These physiological trauma could then lead to fatal

cardiac arrest and stroke. Hill (1978) also reported that sensory organs, especially the eyes and ears, were damaged by pressure impulses. Trauma included hemorrhage of capillaries in the eye and

severing of the optic nerve. In general, the most severe damage occurred in the smallest animals,

suggesting that size afforded some protection against harmful consequences (Hill 1978).

The impacts of offshore oil and gas platform removals and seismic operations on sea turtles are a

necessary concern because of their overlap in time and space. There are five sea turtle species

occurring in the Gulf of Mexico: the Kemp's ridley (Lepidochelys kempi), the loggerhead (Caretta

caretta), the hawksbill (Eretmochelys imbricata), the green turtle (Chelonia mydas), and the

leatherback turtle, (Derinochelys coriacea). Under the Endangered Species Act of 1973, all are

designated as endangered or threatened species because their populations have been greatly depleted

worldwide as a result of human activities (Lutcavage et al. 1997). In the Gulf of Mexico, sea turtles

are seasonably abundant inshore, but their ranges may extend offshore and several species are highly

migratory. Some sea turtles, particularly loggerhead and green turtles, use oil and gas structures as

foraging and resting habitats (Klima et al. 1988; Gitschlag et al. 1997), and even the highly pelagic

leatherback has been sighted under platform pilings. Offshore platforms function as artificial reefs,

and like other structures such as fishing piers, maybe attractive to sea turtles because they offer food

resources and shelter.

Sea turtles are uniquely adapted for a life at sea, and primarily one of submergence. Their body plan

is streamlined, and their limbs and shell are shaped for efficient hydrodynamics and underwater

propulsion. They have orbital salt glands to eliminate excess salts and maintain fluid balance, a

reduction in bony shell material, and very compliant chest walls to cope with pressure changes associated with diving. On average, sea turtles spend 95% of their time submerged, engaged in

feeding, swimming, and resting, and are capable of some of the longest and deepest dives known

among breath hold divers (Lutcavage and Lutz 1997).

Based on biotelemetry studies of freely diving sea turtles, the range of dive patterns is quite broad, and varies in relation to species, sex, size, activity, and water temperature. Even within a species

such as the Kemp's ridley, routine voluntary dives may last only 12-18 minutes, while occasionally

they may range upwards of several hours (Byles 1989). In coastal regions juvenile loggerhead sea

turtles routinely make short, shallow dives, but offshore they may dive to over 200 m and submerge

for 40 minutes or more (Lutcavage and Lutz 1997). The common theme linking all sea turtle dive patterns is repetitive diving: i.e. sea turtles spend onlya few minutes per hour at the surface where

we can see and detect them. This remains a challenge of all monitoring programs.

Sea turtles initiate a dive by holding their breath after inspiration. The lung is the primary oxygen

store (with the exception of a deep diving leatherback turtle), but also serves as the maj or buoyancy organ (Lutcavage and Lutz 1997). Regulation of buoyancy is critical for a marine air-breather that

feeds, travels, avoids predators, and rests while submerged. The lung is a paired, wedged shaped organ attached by a thin membrane to the carapace and fused to the dorsal ribs. Turtles lack a
489

diaphragm, and ventilate their lung at the surface through movements of their pectoral and pelvic

girdle muscles. Their chest wall is very compliant, which is important for these divers since they

regularly face large pressure changes related to diving. The sea turtle lung bears a superficial

resemblance to mammalian lungs, being finely divided, and has a large respiratory gas surface area

and a delicate gas-tissue barrier only a few cell layers thick. Like the lungs ofsome marine mammal

divers, the sea turtle lung also has unique structural adaptations related to diving. Airways are

reinforced with myoelastic tissue that affords some protection against irreversible collapse at depth,

and also supports high ventilatory flow rates. Although these adaptations apparently protect the lung

against routine pressure-volume changes, compensation is limited, and underwater blast impacts

produce time-pressure impulses of a vastly different scale. Based on published impacts on other

vertebrate lungs (Hill 1978), the sea turtle lung would be vulnerable to gas emboli and disruption

of respiratory ftmnction. In experimental studies, green sea turtles undergoing rapid decompression

in hyperbaric studies died from pulmonary gas emboli (Berkson 1967).

Sea turtles routinely hold their breath only as long as their lung oxygen supply is accessible. If they

are to remain active and capable of repetitive diving, they have to surface and replenish oxygen

stores to remain within aerobic limits (Lutcavage and Lutz 1991). The fact that their breath hold

capacities are limited is reflected in enforced tow time studies conducted by the NMFS (Henwood

and Stuntz 1987). After 60 minutes of enforced tows, the rate of comatose and dead turtles rose

exponentially; sea turtles were submerged past their normal tolerance and became asphyxiated and

drowned. When sea turtles and other vertebrate divers submerge, they undergo physiological

changes, known collectively as the diving response, to conserve energy stores. This response results

from a suite of integrated events in the central and peripheral nervous system that modulate heartrate

and circulation, and meters oxygen delivery to critical organsbrain, heart, and working muscles.

For example, diving heart rates range from a few beats per minute during rest periods to high rates

associated with swimming exercise. Heart rate is also subject to conscious control, because sea

turtles often increase their heart rate and cardiac output in anticipation of surfacing. Damage

resulting from concussion, gas emboli, shock, or lung collapse could interfere not only withoxygen

delivery to vital organs, but could also insult the central nervous system controlling the protective

dive response, and which might prove fatal.

Unlike marine mammals, sea turtles are primarily heterotherms that regulate their body temperatures

through shifts in behavior (Spotila et al. 1997). But vasomotor responses allow them to cool and

warm by varying blood flow to the skin and periphery. For example, in the tropics, nesting

leatherbacks sometimes are noticeably pink from vasodilation to the skin, which may lower body

temperatures after strenuous nesting activity. Some sea turtles bask on beaches (Pacific green turtles)

or at the sea's surface (leatherbacks) to warm themselves. It is therefore conceivable that disruption

of the vasornotor response could compromise thermoregulatory functions and undermine fitness.

Beyond the cardiorespiratory and circulatory system, there is little information on the impacts of

underwater explosions on other organs, particularly the sensory systems. Unfortunately, information

on basic structure and flmction of sea turtle vision is limited, but for a visual predator like the sea

turtle, it is conceivable that damage to the eyes and optic nerve would have detrimental impacts on

behavior. Slightly more information is available from studies on the structure of sea turtle ears and
490

hearing (e.g. Ridgeway 1969; Lenhardt et al. 1983; Moein et al. 1994; Moein Bartol et al. in press).

These studies found that the sea turtle ear has unique components and responses not present in other

turtles. Like the marine mammals, the sea turtles lack an external ear, and instead have a layer of

thick subtympanal fat composed of facial tissue. Their ears are structured for sound conduction

through bone and water, and the bones of the skull, carapace and columellar are sound transducers,

but subtympanal fat may serve a yet undefined role in underwater hearing (Dr. D. Ketten, pers.

comm.). Sea turtle ears respond primarily to low frequency sound, in the 200-700 hz range

(Ridgeway 1969; Moein Bartol et al. in press).

Beyond basic studies on hearing, there have been only a few attempts to identify how sea turtles

respond to seismic activity and air guns, considered as a possible deterrent for dredging activities

(Moein Bartol et al. 1994). In experimental field trials, behavioral responses to air guns varied

among trials, suggesting that individuals habituated to discharges. However, following exposure to

air gun trials, loggerhead sea turtles exhibited short-term physiological stress, including increased

plasma cortisol, glucose, and white blood cell counts, although handling may have also contributed

to these changes. Loggerheads also suffered a temporary phase shift in auditory evoked response,

but this resolved within two weeks, suggesting that disruption of hearing physiology was of short

duration. In general, we have very little information that would allow us to evaluate the potential

impacts of underwater explosions and seismic activities on sea turtle vision and hearing.

Nonetheless, in the underwater world, these senses are certainly critical to survival.

DOCUMENTED IMPACTS ON SEA TURTLES

If we are to fully evaluate the scope of impacts of explosive platform removals and seismic activities

on the sea turtles, it is helpful to review documented case histories. Concern was first raised in 1986,

when 51 sea turtle carcasses, primarily juvenile Kemp's ridleys, stranded within a 30-day period on

Texas beaches, in proximity to 10 platform removal operations (Klima et al. 1988). That summer,

the NMFS conducted a field trial holding fourjuvenile loggerheads and four Kemp's ridleys in cages

distributed 260-915 m away from an explosive removal (using four 23 kg charges of nitromethane

placed in pilings). Although none died, five out eight sea turtles were rendered unconscious, and

damages included fractured scutes, immobility, cloacal prolapse, capillary damage in the eyes, and

persistent abnormal vasodilation (in the loggerheads). Although all of the physiological insults

resolved within two weeks, these animals were given full supportive veterinary care, and it is

possible that in the wild they may not have fared so well. In the very fewcases where sea turtles have

been harmed by monitored explosive platform removal operations, conclusive links were established

by prompt retrieval and expert examination of the carcass. Because of rapid post mortem

decomposition, by the time sea turtles strand on Gulf of Mexico beaches, it is virtually impossible

to establish cause of death, which may have resulted from any number of causes such as drowning

in fishing gear, ship strikes, underwater explosions, intentional killing, and ingestion of toxic marine

organisms.

The lessons learned from the long-term NMFS and offshore industrysea turtle and porpoise observer

program is that monitoring can reduce mortalities but is not 100% effective (G. Gitschlag, pers.

comm.). Lacking definitive studies, at this point we can only make reasonable assumptions that oil
491

and gas exploration activities may impact sea turtles Table 2G. 1) based on what we know about their

functional anatomy, physiology, and behavior Our ability to protect sea turtles from harm would also

be advanced by having a better understanding of basic functions of their sensory systems. If we are

to protect endangered sea turtles in their Gulf of Mexico habitats, common sense, caution, and an

understanding of their unique life styles should help us significantly reduce harmful interactions.

Table 2G. 1. How oil and gas exploration activities may impact sea turtles.

Vulnerable to damage

Sea turtle respiratory system

Buoyancy control and diving

Central nervous system

Heart

Vasomotor control

Sensory systems: ears and eyes

Visceral organs

Behavior: feeding, energetics

REFERENCES

Berkson, H. 1967. Physiological adjustments to deep diving in the Pacific Green turtle (Chelonia

mydas agassizii), Comp. Biochem. Physiol 21:507-520.

Byles, R. A. 1989. Satellite telemetry of Kemp's ridley sea turtle, Lepidochelys kempi, in the Gulf

of Mexico. In Proceedings of the Ninth Annual Workshop on Sea Turtle Conservation and

Biology. NOAA Tech. Memo NMFS-SEFSC-232, 306 p.

Gitschlag, G.R., Herczeg, B.A., and T. R. Barcak. 1997. Observations of sea turtles and other marine

life at the explosive removal of offshore oil and gas structures in the Gulf of Mexico. Gulf

Research Reports 9:247-262.

Goertner, J.F. 1982. Prediction of underwater explosion safe ranges for sea mammals. Naval Surface

Weapons Center NSWC TR 82-1 88. Dahlgren, VA

Henwood, T.A., and W.E. Stuntz. 1987. Analysis of sea turtle captures and mortalities during

commercial shrimp trawling. Fish. Bull 85:813-817.

Hill, S.H. 1978. A guide to the effects of underwater shock waves on arctic marine mammals and

fish. Institute of Ocean Sciences, Patricia Bay, Sidney, BC Canada. Pacific Marine Science

Report 78-26.
492

Klima, E.F., Gitscblag, G.R., and M. L. Renaud. 1988. Impacts of the explosive removal of offshore

petroleum platforms on sea turtles and dolphins. Marine Fisheries Rev. 50: 4 1-42.

Lenhardt, M.L., Beilmund, S., Byles, R. And J. Musick. 1983. Marine turtle reception of bone

conducted sound. J. Aud. Res. 23:119-125.

Lutcavage, M. And P.L. Lutz. 1997. Diving Physiology. In The Biology of Sea Turtles. Eds. P.L. Lutz and J.A. Musick. pp. 277-296.

Lutcavage, M., Plotkin, P., Witherington, B., and P.L. Lutz. 1997. Human impacts on sea turtle

survival. In The Biology of Sea Turtles. Eds. P.L. Lutz and J.A. Musick.

Lutcavage, M.E., and P.L. Lutz. 1991. Voluntary diving metabolism and ventilation in the

loggerhead sea turtle. J. Exp. Mar. Biol. Ecol. 147: 287-296.

Moein Bartol, S., Musick, J.A., and M. L Lenhardt. In press. Auditory evoked potentials of the

loggerhead sea turtle, Caretta caretta. Copeia.

Moein, S.E., Musick, J.A., Keinath, J.A., Barnard, D.E., Lenhardt, M., and R. George. 1994.

Evaluation of seismic sources for repelling sea turtles from hopper dredges. (unpubl. final report

submitted to the U.S. Army Corps of Engineers, Waterways Experiment Station). VIMS, Gloucester Pt., VA.

Ridgeway, S.H. 1969. Hearing in the giant sea turtle Chelonia mydas. Proc. Nat. Acad. Sci 64:884-

890.

Spotila, J.R., O'Connor, M.P., and F.V. Paladino. 1997. Thermal biology. In The Biology of Sea Turtles. Eds. P.L. Lutz and J.A. Musick.

Yelverton, J.T. 1973. Safe distances from underwater explosions for mammals and birds. Lovelace

Foundation for Medical Education and Research, Albuquerque, NM. 64pp.

Dr. Molly Lutcavage is a Research Scientist at the NewEngland Aquarium's Edgerton Laboratory

and directs research programs on sea turtles and bluefin tuna. Her research expertise includes sea

turtle physiology, ecology, and pollution biology. Dr. Lutcavage received her B.A. in biology and

enviromnental studies from the University of Pennsylvania, her M.Sc. in marine science from the

Virginia Institute of Marine Science, College of William and Mary, and her Ph.D. in biological

oceanography from the Rosenstiel School of Marine and AtmosphericScience, University of Miami.
GIS Activities: Introduction

The MMS Coastal and Ocean Resource

Information System (CORIS)

Document Not Submitted

Integrating Environmental Studies

Data into CURlS: The Deepwater

Data Model

Document Not Submitted

The Gulf-Wide Information System

Database: What's Completed; What's

To Be Done

Document Not Submitted

Facilitating Integrated Regional Ocean

Management Using a Web-Based

Geographic Information System

GIS and Oil Spill Contingency

Planning in Louisiana

Document Not Submitted

SESSION 2H

GIS ACTIVITIES

Co-Chairs: Dr. Norman Froomer and Ms. Michelle Morin

Date: December 10, 1998

Presentation Author/Affiliation

Dr. Norman Froomer

Ms. Michelle Morin

Minerals Management Service

Gulf of Mexico OCS Region

Dr. Norman Froomer

Ms. Michelle Morin

Minerals Management Service

Gulf of Mexico OCS Region

Mr. Peter Bottengerg

Environmental Systems Research Institute

Dr. Norman Froorner

Minerals Management Service

Gulf of Mexico OCS Region

Ms. Lynda Wayne

Louisiana State University

Mr. Nicholas Schmidt, Program Manager

Ms. Cindy Fowler, Senior Spatial Data Analyst

National Oceanic and Atmospheric Administration

Coastal Services Center

Mr. Robert M. Neely, Programmer Analyst

Mr. Eric Treml, Programmer Analyst

Technology Planning and Management Corporation

Mr. David Gisclair

Louisiana Oil Spill Coordinator's Office

493
GIS ACTIVITIES: INTRODUCTION

Dr. Norman Froomer

Ms. Michelle Morin

Minerals Management Service

Gulf of Mexico OCS Region

The GIS Activities Session focused on activities underway at MMS to develop Geographic

Information System databases and applications for use in offshore natural resource management. The

first presentation by Norman Froomer and Michelle Morin described the MMS Coastal and Offshore

Resource Information System (CORIS). CORIS is a relational database that holds the environmental

data that MMS will use for regulatory and planning analyses. CORTS stores tabular data in an

ORACLE database and use s the Spatial Database Engine for storing spatial data.

MMS intends to incorporate data deliverables from MMS Environmental Study Program data

deliverables when appropriate. The next presentation by Mr. Peter ]3ottenberg described the work

that Environmental Systems Research Institute (ESRI) is doing for MMS to assist in this objective.

ESRI is developing data formats for data deliverables from deepwater environmental studies andGIS

applications that will use these data for regulatory and planning analyses.

Much of the data currently contained in CURlS was developed through the Gulf-Wide Information

System (OWlS) project. GWJS developed a consistent and complete environmental database

extending from Corpus Christi, Texas to Tampa, Florida. These data were developed by each of the

Gulf states and several federal agencies according to database specifications that allow the diverse

data sets to be used together for regional analyses. The next presentation by Dr. Norman Froomer

and Ms. Michelle Morin described the status of the GWIS data, which is currently in the Quality

Assurance/Quality Control phase of completion.

Mr. Nicholas Schmidt of the National Oceanic and Atmospheric Administration (NOAA) described

a project that the NOAA Coastal Services Center has developed to support ocean management

through a web-based GIS. The NOAA project depicts geographically laws and regulatory statutes

with implied geographic boundaries that were not explicitly specified in original documents.

Finally, Mr. David Gisclair of the Louisiana Oil Spill Coordinator's Office described a project to develop a GIS oil spill and emergency planning database for the state of Louisiana. MMS has

worked cooperatively with LOSCO on this project in that the data that this project develops will be

incorporated into the MMS CORIS database, and the GWIS biological data for Louisiana will be

incorporated into the LOSCO database. The GIS Activities Session focused on activities underway

at MMS to develop Geographic Information System databases and applications for use in offshore

natural resource management.

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496

FACILITATING INTEGRATED REGIONAL OCEAN MANAGEMENT USING

A WEB-BASED GEOGRAPHIC INFORMATION SYSTEM

Mr. Nicholas Schmidt, Program Manager

Ms. Cindy Fowler, Senior Spatial Data Analyst

National Oceanic and Atmospheric Administration

Coastal Services Center

Mr. Robert M. Neely, Programmer Analyst

Mr. Eric Treml, Programmer Analyst

Technology Planning and Management Corporation

AB S TRACT

Because existing governance and management regimes for ocean resources in the U.S. are

fragmented, complex, and thus poorly understood, the nation is ill-equipped to address the inevitable

conflicts and problems arising offshore. A wide variety of laws, regulations, programs, and special

jurisdictions have evolved over time to protect, develop, and manage ocean resources. Ocean policies

and programs, however, have historically been developed and implemented as single-purpose

regimes, with little thought to how they would interact with other resource management

considerations (National Research Council 1997). At both the national and international levels, 1998

has been declared "Year of the Ocean," and consensus among ocean and coastal managers is building

in favor of more integrated, comprehensive ocean management supported by the best available

science and spatial information. Hence, there is a great need for the development of ocean

management information systems that integrate environmental data with spatially referenced legal,

political, and jurisdictional frameworks to help resource managers and policy makers make sense

ofoffshorejurisdictional complexities. With the National Oceanic and Atmospheric Administration

providing leadership for the U.S., staff at its Coastal Services Center (CSC) are building upon

ongoing state-level efforts to develop a regional model for a Web-based ocean governance and

management geographic information system (GIS). This prototype - the Southeast Ocean Planning

GIS (Ocean GIS) - will help facilitate the shift from fragmented management of individual ocean

resources to integrated management of ocean ecosystems. It will do so by providing resource

managers in the Carolinas, Georgia, and Florida access to regional geo-referenced regulatory and

environmental spatial data critical to timely, integrated decision making and analysis of complex and

often conflicting jurisdictional issues. In addition, the Ocean GIS will serve as a model for regional

ocean management information systems. To assess its effectiveness and potential usefulness in

obtaining these objectives, CSC staff will solicit feedback from states with a stake in ocean

management issues to evaluate the utility of the Ocean GIS and to identif5i deficiencies common to

this and other similar GIS-based ocean and coastal planning tools. The results of this evaluation will

serve as guide posts for the ongoing development of the Ocean GIS and similar tools designed to

facilitate comprehensive, integrated approaches to ocean management.
]NTRODUCTION

The ocean waters of the southeastern U.S. comprise one of the richest and most productive of

our nation's vast marine resource regions. The inhabitants of the coastal states of this region,

whether directly or indirectly, benefit in many ways from the bounty of the Atlantic Ocean and

Gulf of Mexico. The ocean and coastal areas of the Southeast support multiple activities,

including commercial and recreational fisheries, oil and gas production, coastal recreation,

commercial trade, and essential ecosystem functions. Though the warm waters, low-lying sandy

beaches, and expansive tidal marshes distinguish this region from others in our nation's immense

marine territory, it, too, is increasingly affected by humankind's changing relationship with the

seas. In the Southeast, as elsewhere in the U.S., the environmental quality of marine areas and

resources, and the economic value of ocean and coastal industries, such as trade, tourism, fishing,

and energy extraction, could be jeopardized unless decisive steps are taken to protect and

effectively manage these sensitive ocean and coastal environments (Heinz Center 1998).

A wide variety of laws, regulations, programs, and special jurisdictions - collectively constituting

the region's ocean governance and management framework - have been developed over time to

protect, develop, and manage ocean resources. Ocean policies and programs typically were

developed and implemented as single-purpose regimes, with little thought to how they interacted

with other resource management considerations. From the shoreline seaward to the 200-nautical

mile boundary of the U.S. Exclusive Economic Zone (EEZ), the federal government, coastal

states, and local jurisdictions have many overlapping interests and authorities. Balancing the

need for renewable ocean resource use and enjoyment with extraction of nonrenewable

resources, navigation, recreation, and protection of the ocean ecosystem presents one of our

nation's greatest challenges and responsibilities for the 2l' century (National Research Council

1997).

Fortunately, numerous efforts are currently underway to address the need for more

comprehensive, integrated approaches to regional ocean and coastal management. At the

international level, 1998 has been declared "Year of the Ocean" by the United Nations in an

effort to focus attention on ocean issues. To complement this international effort, the U.S. has

also declared 1998 "Year of the Ocean," with the National Oceanic and Atmospheric

Administration (NOAA) assuming a prominent leadership role. Other key components of the

U.S. effort to address ocean management concerns include possible Congressional ratification

of the United Nations Convention on the Law of the Sea, and political efforts to establish a highlevel, Stratton-type committee to evaluate and make recommendations for improving the U.S.

ocean governance and management framework. As these initiatives continue to focus attention

on important ocean issues, they also underscore the need for easily accessible geographic

information that enables resource managers to conduct critical spatial analyses. To meet these

needs, the NOAA Coastal Services Center (CSC) and its partners have developed a prototype

Web-based regional Ocean GIS that will help resource managers make sense of the complex

jurisdictional, political, and legal frameworks that constitute our national ocean governance and

management framework.

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498

THE NEED FOR REGIONAL SPATIAL ANALYSIS CAPABILITIES

The existing governance and management regimes for ocean resources in the southeastern U.S.,

as elsewhere, are fragmented, complex, and thus poorly understood. Generally, the states have

control of the sea bottom and marine resources out to the three-mile federal-state boundary (43

U.S.C. § § 1301 et seq.). Within this area, states have the authority to manage, administer, lease,

develop, and use the natural resources of the ocean; the federal government retains considerable

control over commerce, navigation, defense, fisheries, and international matters. Under section

8(g) of the Outer Continental Shelf Lands Act, states share nearshore revenues from production

within three nautical miles seaward of the federal-state boundary. States may also exert influence

over federal activities within the U. S. Territorial Sea, which extends 12 nautical miles seaward

from the shoreline (or 9 nautical miles beyond most federal-state boundaries), as well as within

the EEZ, which may extend 200 nautical miles or more seaward from the shoreline.

Federal agencies have a variety of overlapping authorities and jurisdictions. Some of the most

important players include the U.S. Coast Guard, U.S. Environmental Protection Agency, U.S.

Minerals Management Service (MMS), U.S. Arny Corps of Engineers, and NOAA. This

fragmented approach to management of ocean resources at the national level often results in

redundant efforts, inefficiency, ineffectiveness, and lack of coordination among agencies with

tangled, overlapping jurisdictions. Perhaps more problematic are the unidentified jurisdictional

gaps in the existing governance framework that potentially can hinder effective ocean

management and the appropriate use, conservation and protection of important ocean resources.

These factors emphasize the need for the development of regional spatial frameworks such as

the Ocean GIS which will help make sense of offshore jurisdictional complexities.

Because natural resources typically transcend political boundaries, and because many ocean

issues span multiple state and federal agency jurisdictions, regional cooperation is an essential

component of efforts to integrate approaches to ocean management. Furthennore, comprehensive

ocean management is dependent in large part upon the contributions and efforts of the individual

coastal states. Unfortunately, only a few coastal states - including California, Oregon, and

Florida - have attempted to compile the data necessary for integrated, coordinated approaches

to ocean planning, governance, and management. Each has met withsome success, but also with

problems, such as lack of essential data. Such data is typically dispersedamong many federal and

state agencies, which clearly suggests the need for development of a consistent, managementoriented data framework. To be effective, the content and structure of a digital spatial database

must address the important issues of ocean planning and governance and provide resource

managers with a basis for assessing alternative management strategies and tactics.

BUILDING A PROTOTYPE INTERNET-BASED REGIONAL OCEAN

GEOGRAPHIC INFORMATION SYSTEM

Within the past decade, the development and increased availability of geographic information

system (GIS) technologies have provided natural resource managers with powerful decision

making tools. Capable of storing, processing, analyzing, and displaying multiple overlapping
spatial data sets, GIS has typically been applied to terrestrial systems or relatively small-scale

marine environments. However, the applicability of GIS to large-scale marine regions is

particularly appealing given the apparent need for improved regional approaches to ocean

management.

The idea for a regional ocean GIS for the Southeast was originally conceived by NOAA's Office

of Ocean and Coastal Resource Management (OCRM) and the State of North Carolina.

Following this genesis, a partnership was forged between OCRM and NOAA CSC, which was

tasked with providing technical leadership for the development of a regional Ocean GIS. During

1996 and 1997, OCRM and CSC held a series of scoping meetings with partners from the States

of North Carolina, South Carolina, Georgia, and Florida, as well as other relevant federal and

regional agencies, to identify priority issues within the region. Concurrently, the Florida Marine

Research Institute (FMRT) developed a prototype ocean GIS for Florida's extensive marine areas.

The product of this effort - the Florida Statewide Ocean Resource Inventory (SORT) - yielded

an Internet mapping and data retrieval application for 150 geo-referenced marine and coastal data

sets (Florida Department of Environmental Protection 1998). In early 1998, CSC and FMRI

began an ongoing effort to expand upon SORT by building a prototype Ocean GIS to include the

marine region bounded by the Carolinas, Georgia, Florida, the U.S. EEZ, and maritime

boundaries.

The Ocean GIS project built an integrated issue-driven Internet interface with an interactive

Web-based GIS tool usingthe Environmental Systems Research Institute's (ESRI) MapObjects

Internet Map Server and Visual Basic®. MapObjects is a collection of mapping and GIS

components, including an ActiveX control (OCX) and ActiveX automation objects. For this

project, MapObjects was used within the Visual Basic development environment.

As with SORT, a key objective of this projectwas to develop an inventory of fully attributed data

sets documenting the spatial extent of the southeastern regional ocean governance and

management framework. In this the initial phase of regional prototype development, CSC project

staff focused on federal-level framework components. In addition, effort was also applied to

locating and incorporating many of the issue-related environmental data sets identified as

important by project partners.

The U.S. federal management framework is comprised of several important sub-components: the

legislative framework, which establishes the legal mandate for regulation and management of

ocean resources; the institutional framework responsible for implementing those mandates; and

political boundaries that determine, in large part, the geographic scope of management

jurisdictions. A functional regional Ocean GIS must include geographically and legally accurate

depictions of these components to facilitate meaningful and substantive analyses on the part of

resource managers. However, because legal and geographic definitions are sometimes

inconsistent or uncertain, and because the fundamental purpose of statutory components vary

depending on legal intent, these prerequisites present some interesting challenges to those

charged with assimilating, interpreting, and developing geo-referenced legal information.

Because it sometimes highlights deficiencies, the process of geo-referencing the management

499
500

and governance framework is, in itself, an exercise in facilitating the shift to comprehensive,

integrated ocean governance and management.

Geo-referencing the U.S. Federal Legal Framework

Numerous federal laws are relevant to the governance ofocean and coastal resources. Because

the authority and influence of many laws with respect to ocean management issues are often

obscure or uncertain, CSC had first to identify those laws that constitute the cornerstones of

ocean governance in the southeastern U.S. These laws can be characterized broadly as those that:

* Designate or authorize marine protected areas (e.g., National Marine Sanctuaries,

National Estuarine Research Reserves, National Parks and Seashores, National

Estuary Programs).

Designate or authorize site-specific uses (e.g., dredged material disposal sites,

fishery enhancement areas, military training areas, National Priority List sites).

Establish broad, geographically comprehensive regulatory authority (e.g.,

Endangered Species Act, Marine Mammal Protection Act, Coastal Zone

Management Act).

Establish geographically indiscrete or undefined regulatory authority.

To define the geographic extent of pertinent laws, CSC compiled an inventory of key federal

statutes with direct relevance to ocean and coastal resource management. To accomplish this

task, CSC project staff relied upon the expertise of numerous federal and state agency workers,

the developers of SORI, the U.S. Code, the Code ofFederal Regulations, and numerous other

legal sources. After compilation, the spatial extent of each law, ifrelevant, was determined either

through reliance upon the sources listed above, or through data developed by CSC, other

agencies, and/or Ocean GIS partners.

Geo-referencing the U.S. Federal Institutional Framework

A process parallel to that utilized to inventory and determine legislatively-determined spatial

extents was employed to identify key components of the U.S. federal institutional framework for

ocean management. Numerous federal agencies share responsibility for implementing and

enforcing federal laws drafted to manage and promote the stewardship and appropriate use of

marine resources. In fact, any one agency is typically responsible for ensuring compliance with

a number of federal laws, and the institutional structures of these agencies are often as complex

as the laws they are mandated to enforce. For example, the top-down institutional hierarchy of

the U.S. Army Corps of Engineers includes divisionsthat are organized within unique regions

into regulatory districts (typically defined by state boundaries), civil works districts (typically

defined by watersheds), and military works districts (typically defined by combinations of state

boundaries). Other federal organizations involved in themanagement of ocean resources include

the U.S. Department of Commerce (NOAA National Marine Fisheries Service, NOAA National

Ocean Service [NOS]), the U.S. Department of the Interior (National Park Service, Department

of Fish and Wildlife, MMS), the U.S. Department of Transportation (Coast Guard, Maritime
Administration), the U.S. Department of Agriculture (Forest Service, Bureau of Land

Management), the U.S. Environmental Protection Agency, and the Federal Emergency

Management Agency. Each of these agencies is generally divided into geographically and

programmatically distinct jurisdictional units responsible for regional implementation and

enforcement of federal programs. Hence, as with the legal framework, the federal institutional

framework is a complex regime of geographically overlapping jurisdictions, the mapping of

which is essential to enhanced regional ocean management.

To spatially define these multiple jurisdictions within the Ocean (JIS prototype, CSC relied

extensively upon many of the same sources mentioned with respect to the development of georeferenced legislative data layers. (At the time of this writing, spatial data for some of these

components had yet to be developed.)

Geo-referencing Political Boundaries

The final spatial policy component of the ocean governance and management framework is

composed of numerous political boundaries that define the extent of state and national

sovereignty over ocean territories and the resources therein. These boundaries include the

state/federal boundary, the U.S. Territorial Sea boundary, the U.S EEZ boundary, and

international maritime boundaries. To acquire spatial data for these boundaries, CSC relied

primarily upon MMS and NOAA NOS.

Integration with Other Data Layers

The initial Web-based prototype of the Ocean GIS also makes available a number of

environmental data layers, such as those delineating the spatial extent of physicalresources (e.g.,

bathymetry, bottom type, shoreline) and living resources (e.g., coral communities). Important

economic layers include active offshore oil and gas lease blocks and commercial ports.

Using ESRI's MapObjects Internet Map Server, these disparate spatially referenced data layers

were integrated into the prototype Web-based regional Ocean GIS.

Synthesis and Presentation of Information Via the Internet

Internet users who visit the Ocean GIS website have unrestricted access to the data, which can

be downloaded in ESRT coverage and shapefile formats for use in ArcView® and ARC/INFO®

GIS applications. In addition, users are able to view these data spatially, examine their associated

attributes, navigate to relevant on-line resources through hyperlinks embedded in the tabular

data, perform basic analyses, identify relevant legislation and agency jurisdictions at any

geographic location, and print reports and maps via the Internet. All of these functions are

available to users without the purchase of any software except a basic Web browser.

501
502

Other key features of the Ocean GIS site include links to the following:

Summary and Federal Geographic Data Committee-compliant metadata records

for all data layers

"Scenarios" that utilize available data layers to demonstrate the applicability of

a regional Ocean GIS to various management issues, or highlight deficiencies in

digital geographic data and data sources

Statutory summaries, U.S. Code, and relevant on-line programmatic and

managing agency resources

CONCLUSION

Though much has been accomplished to date, the need for continued development of the Ocean

GIS is great. (In fact, development of the Ocean GIS is an ongoing project at CSC.) The present

data inventory included in the prototype is substantial but insufficient in some cases to provide

for truly meaningful analyses and suitable resolution of ocean issues. This deficiency is the result

of numerous factors that may be overcome in the future, includingthe limited time and resources

committed to this project to date, inadequacies in available data, lack of important data, and

concern over the legal and geographic accuracy of certain "official" data sources.

In addition to data concerns, much has yet to be learned about how to develop and maintain a

fully functional regional Ocean GIS. As it has from the outset, CSC remains sensitive to the

needs of its partners and committed to the development of a useful regional management tool.

To ensure that these objectives are met, CSC has established a partnership with Oregon State

University's (OSU) Marine Resource Management program to conduct an assessment of states'

needs and perceptions with respect to the utility of a regional Ocean GIS. Funded by CSC and

the National Spatial Data Infrastructure (NSDI) Benefits Program, this effort will team CSC staff with marine policy and management experts at OSU to determine how best to ensure that the

Ocean GIS achieves the NSDI-mandated objectives of efficiency, effectiveness, and equity.

The target population for the benefits analysis will consist ofthe state coastal and ocean resource

management community. Working closely with CSC and utilizing a jointly-developed

assessment framework, researchers at OSU will compare and contrast three approaches to ocean

management - (1) regional (e.g., the Southeast), (2) single-state (e.g., Oregon, California) and

(3) no ocean management policy (e.g., Louisiana).

To measure the benefits associated with these three approaches, OSU will utilize the assessment

framework to conduct an inventory of existing state ocean management programs and the degree

to which GIS is currently being used to implement intrastate andlor regional program objectives. Case studies will subsequently be developed that highlight states' needs with respect to the

application of GIS technologies, digital spatial data, and the Internet, to achievement ofocean

management objectives. By identifying and highlighting the needs of state ocean management

programs through case studies, this assessment will provide valuable feedback and guidance for ongoing development and application ofa regional Ocean GIS. In addition, it will capitalize on
the existing momentum and agreement among many managers that a GIS can serve as a rallying

point for regional integrated ocean management.

REFERENCES

Florida Department of Environmental Protection Marine Research Institute and the National

Oceanic and Atmospheric Administration Coastal Services Center. 1997. South Atlantic

Ocean GIS (white paper). St. Petersburg, FL: Florida Marine Research Institute.

H. John Heinz III. Center for Science, Economics and the Environment (Heinz Center). 1998.

Our Ocean Future. Washington, DC: Heinz Center.

National Research Council (NRC). 1997. Striking a Balance: Strengthening Marine Area

Governance and Management. Washington, DC: National Academy Press.

Nicholas Schmidt holds a B.S. in marine science and an M.S. in geography from the University

of South Carolina. He has worked at NOAA's Coastal Services Center in Charleston, SC for

almost three years as GIS Program Manager. Prior to NOAA, he worked at NASA's Stennis

Space Center for six years in support of NASA's Commercial Remote Sensing program.

Cindy Fowler has a B.S. from the University of South Carolina in geography and an MS. in

enviromriental information systems from Ohio State University. She has over 19 years of

experience working with geographic information systems (GIS) in a variety of fields including

forestry, cadastral, natural resources, coastal and ocean GIS. Ms. Fowler is currently working

with NOAA at the Charleston Coastal Services Center.

Robert Neely obtained a B.A. in economics and English from the University of North Carolina,

Chapel Hill and an M.S. in marine resource management from Oregon State University. Mr.

Neely is knowledgeable about marine policy and coastal zone management issues. He is

currently involved in the development of an online ocean planning and governance marine GIS

at the NOAA Coastal Services Center, where he is employed as a programmer analyst by

Technology, Planning and Management Corporation.

Eric Treml has a B.S. from the University of Wisconsin-Superior in aquatic biology and ecology

and is completing his M.S. in marine biology at the University of Charleston in South Carolina.

He has over three years' experience working in geographic information science, ranging from

coastal marine field surveys and aerial photography interpretation to, most recently, maritime

boundaries. Mr. Treml is currently employed as a programmer analyst by Technology, Planning

and Management Corporation and works as a contractor at the NOAA Coastal Services Center.

503
SESSION 2J

PROPOSED REVISIONS TO THE MMS OIL AND GAS LEASE FORM:

A WORKSHOP FOR INDUSTRY COMMENTS

Co-Chairs: Mr. Chuck Hopson and Mr. Steve Waddell

Date: December 10, 1998

Presentation Author/Affiliation

505

Session Overview Mr. Steve Waddell

Minerals Management Service

Gulf of Mexico OCS Region
SESSION OVERVIEW

Mr. Steve Waddell

Minerals Management Service

Gulf of Mexico OCS Region

This session consisted of a four-part workshop to elicit comments from the industry regarding the

proposed revisions to the MMS oil and gas lease form:

Introduction and Team Charter - the introduction to the workshop was to discuss the recent

changes made to the lease fonri document by the lease document team. Our charter was to

review the lease form for present-day application to comply with recent directives on plain

English writing. In the process, we were to take out any provisions that were redundant with

existing regulations.

Comparison of Proposed Revision to Current Lease Form- we discussed with industry the

changes made to the existing form and our reasoning for the changes.

Industry Comment and Open Discussion - basically, industry was not happy with our

revisions. However, a subsequent public workshop was help at the GOMR office and we had

a warm reception. Industry maintains that there is nothing wrong with the existing form and

"if it ain't broke, don't fix it."

Summary and Where Do We Go from Here? - The lease team has reviewed all comments

by industry and has made recommendations to the quality council at headquarters. At the

present time, the lease form has been put on hold indefinitely.

507
INDEX TO AUTHORS

Alford, Mr. John 220

Allen, Mr. Dan 239

Anuskiewicz, Dr. Richard J. 129

Arms, Mr. Christopher 220

Barrera, Mr. Noe C. 255

Beaver, Mr. Carl R. 59, 255

Benfield, Dr. M.C. 33

Biggs, Dr. D.0 288

Boland, Mr. Gregory S. 151, 255

Bottengerg, Mr. Peter 489

Bourgeois, Mr. John A. 267

Cahoon, Dr. Donald R. 267

Caidwell, Dr. Jack 360

Chang, Mr. Joseph C 93

Childs, Mr. Jeff 183

Chinkin, Mr. Lyle R. 96

Clark, Dr. Jerry 253

Collard, Dr. Sneed B 399, 439

Dauterive, Mr. Les 157

Davis, Dr. Randall W. 279, 285

DeJohn, Mr. Ken 230

DiMarco, Dr. Steven F. 415

Ditty, Mr. James 29

Dokken, Dr. Quenton R. 59, 67, 255

Dye, Mr. Timothy S. 116

Evans, Dr. William E. 279, 285, 298, 372

Farooqi, Ms. Talat 29

Fernau, Dr. Mark E. 93

Fowler, Ms. Cindy 492

Froomer, Dr. Norman 491

Gallaway, Dr. Benny 3. 209

Gentry, Dr. Roger 349

Gisclair, Mr. David 489

Gisiner, Dr. Robert C. 379

Gitschlag, Mr. Gregg 53

Gobert, Ms. Angie D 8

Golubev, Dr. Yury 432

Haas, Ms. H.L. 33

Hagman, Mr. Derek K 255

Hamilton, Dr. Peter 427

Handley, Mr. Lawrence R 265. 270

509
510

Hanna, Dr. Steven R. 116

Hays, Dr. Paul R. 245

Herkhof, Mr. Dirk C. 81, 83

Hess, Ms. Nancy 300

Hoggard, Mr. Wayne 294

Howard, Dr. Matthew K. 415

Hsu, Dr. S.A. 104

Hsueh, Dr. Y. 432

Irion, Dr. Jack B. 127, 136

Jackson, Mr. William 163

Jochens,, Dr. Ann F. 415

Johnston, Dr. James B 265

Jones, Mr. William R. 265, 274

Kamper, Mr. Ronnie 230

Keenan, Mr. S.F. 33

Ketten, Dr. Darlene 481

Lang, Dr. William 351

Leben, Dr. Robert 288, 409

Lutcavage, Dr. Molly 483

Luton, Dr. Harry 479

MacDonald, Dr. Ian R 255, 262

Marshall, Mr. Charles F. 83

Moore, Mr. David M 3

Morin, Ms. Michelle 491

Muller-Karger, Dr. Frank E. 409

Mullin, Dr. Keith D 294

Mullin, Mr. Joseph V. 14

Nababan, Mr. Bisman 409

Neely, Mr. Robert M 492

Norris, Dr. Jeffrey C. 298, 372

Nowlin, Jr., Dr. Worth D. 415

Ortega-Ortiz, Mr. Joel 285

Osborne, Mr. Neill 457

Pattengill-Seinmens, Dr. Christy V 161, 166

Piccolo, Mr. Frank 232

Pierson, Dr. Mark 0. 391

Plaisance, Mr. Moe 239

Rankin, Ms. Shannon 298, 372 Ribic, Dr. Christine 300

Richardson, Dr. W. John 481

Riggs, Mr. Terry E. 59

Rike, Mr. J.L. 465

Robb, Mr. Steve 265

Roberts, Dr. Paul T. 116
511

Rogers, Dr. Claudia 453, 478, 479

Rooney, Ms. Terry 220

Ross, Dr. Steve W 194

Russell, Dr. Robert W 259

Schaefer, Ms. Helena 274

Schmidt, Mr. Nicholas 492

Schmidt, Mr. William T. 19

Scholten, Ms. Terry 215

Scire, Mr. Joseph S. 93

Shannon, Mr. Brian E. 234

Shaw, Dr. Richard F. 29, 33

Shrimpton, Mr. Mark 472

Smith, Dr. Michael A. 241

Stanley, Dr. David R 41

Storey, Dr. Keith 472

Strimaitis, Mr. David G. 93

Sulak, Dr. Kenneth J. 194, 203

Tasker, Dr. Mark L 374

Treml, Mr. Eric 492

Tunnell, Jr., Dr. John W. 255

Vigil, Ms. Debra L. xxiii

Vitale, Ms. Lisa D. 67

Vukovich, Dr. Fred 409

Waddell, Mr. Steve 503

Wallace, Ms. Barbara 454

Ward, Dr. E. G. (Skip) 239

Wayne, Ms. Lynda 489

Weaver, Mr. Douglas C. 194, 203

Whitehead, Mr. Michael E. 19

Wilson, Dr. Charles A 41

Wormuth, Dr. JoIm 277

WUrsig, Dr. Bernd 285

Yocke, Dr. Mark 401

Zirnan, Dr. Stephen D. 109
WALLY ADCOX

CONTRACTING OFFICER

MMS

381 ELDEN ST

HERNDON, VA 20170

TOM AHLFELD

OCEANOGRAPHER

MMS

381 ELDON ST

HERDON, VA 20170

RASHED AL-ZAABI

RIKE SERVICE INC

PU BOX 13786

NEW ORLEANS, LA 70185

HANK ALFORD

LAND MANAGER

EXXON

P0 BOX 4778

HOUSTON, TX 77210

JOSE ALICEA

MOSS LANDING MARINE

P0 BOX 52

MOSS LANDING, CA 95039

DAN ALLEN

CHEVRON USA

935 GRAVIER ST

NEW ORLEANS, LA 70112

ALEX ALVARADO

CHIEF PIPELINE SECTION

MMS

1201 ELMWOUD PARK BLVD

NEW ORLEANS, LA 70123

ATTENDEES

PJK ANUSKIEWICZ

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

STEPHANIE AUGUSTINO

GOV RELATIONS MGR

UNOCAL-SPIRIT ENERGY 76

14141 SW FREEWAY

SUGARLAND, TX 77478

RICHARD AUST

SR ENVIRON COORD

PENNZOIL E&P

BOX 2967

HOUSTON, TX 77252

BOB AVEDT

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

ROBERT AVENT

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

BRIAN BALCOM

SR SCIENTIST

CONT SHELF ASSOC

310 3RDAVENE

ISSAQUAH, WA 98027

CHRIS BARKER

LANDMAN

NEWFIELD EXPLORATION

363 N SAM HOUSTON

HOUSTON, TX 77060

513
514

CHARLES BARNES

DALLAS, TX

WARREN BARTON

ENVIRON SCIENTJST

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123-2394

KHALED BAS SIN

BIO OCEANOGRAPHER

IVIIMS

381 ELDEN ST

HERNDON, VA 20170

LINDA BAUCH

API

1220 L STREET

WASHINGTON, DC 20005

WILLIAM BAXLEY

ENVIRON MANAGER

NAVAL SURFACE WARFARE CTR

SOUTH FLORIDA TESTING FACILITY

DANJA, FL 33004

ELIZABETH BECKER

OGDEN ENVRION

1 EAST ANAPAMU

SANTA BARBARA, CA 93101

COLLEEN BENNER

MMS

381 ELDEN ST

HERNDON, VA 20170

THOMAS BERGER

PROGRAM MGR

SAIC

615 OBERLIN RD

RALEIGH, NC 27605

LOUISE BERNEY

ASST CHIEF OFFSHORE COMPLIANCE

USCG

EIGTH COAST GUARD DIST

NEW ORLEANS, LA 70130-3396

DAVID BERNHART

FISHERY BIOLOGIST

NMFS

9721 EXECUTIVE CTR DRIVE NORTH

ST PETERSBURG, FL 33702

DOUGLAS BIGOS

TEXAS A&M

TEXAS A&M UNIV

COLLEGE STATION, TX 77843

BRIAN BLANCHARD

COASTAL STUDIES INST.

LSU

BATON ROUGE, LA 70803

JOY BLEVNS

PETRO ENGINEER

13913 PASMAVINAS

CORPUS CHRISTI, TX 78418

MARY BOATMAN

MMS

1201 ELMWOOD PARK BLVD.

NEW ORLEANS, LA 70123

GREG BOLAND

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

WALTER BONORA

EDITOR

MMS

1849 C STREET NW

WASHINGTON, DC 20240
RICHARD BORNE

REGULATORY TECH

EXXON CO USA

P0 BOX 61707

NEW ORLEANS, LA 70161

DAVID BORNHOLDT

STAFF SPECIALIST

USGS

12201 SUNRISE VALLEY DRIVE

RESTON, VA 20192

PETER BOTTENBERG

ENVIRON SYS RESEARCH INC

380 NEW YORK ST

REDLANDS, CA 92373-8 100

MARK BOUDREAUX

EXXON CO USA

PU BOX 61707

NEW ORLEANS, LA 70161

DONNA BOURG

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

JOHN BOURGEOIS

JOHNSON CONTROLS

700 CAJUNDOME BLVD

LAFAYETTE, LA 70506

VERNESSA BRADFORD

SHELL DEEP WATER

P0 BOX 61933

NEW ORLEANS, LA 70161

BEVERLY BRADLEY

SR RESEARCH SCIENTIST

PLS INC

5044-B BEATLNE RD

LONGBEACH, MS 39560

J.D. BRADLEY

LAND MANAGER

ORYX ENERGY CO

P0 BOX 2880

DALLAS, TX 75221

DWTGHT BRADSHAW

ENVIRON SPECIALIST

LA DEQ

3501 CHATEAU BLVD

KENNER, LA 70065

DARICE BREEDiNG

STAFF PHYSICAL SCIENTIST

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

GARY BREWER

MARINE ECOLOGIST

USGS

1700 LEETOWN RD

KEARNEYSVILLE, WV 25430

RONALD BR[NKMAN

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123 -23 94

STEVE BROOKS

EXXON

P0 BOX 70161

NEW ORLEANS, LA

MURRAY BROWN

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

GREG BRYANT

TRACOR SYS TECH

2611 JEFFERSON DAVIS HWY

ARLINGTON, VA 22202

515
516

JERYNE BRYANT

MMS

381 ELDON ST

HERNDON, VA 20170

PAT BRYARS

STATS ANALYST

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

JENNIFER BUCHANA

MS DMR

1141 BELL VIEW

BILOXI, MS 39530

DAVID BUGG

SR PROJECT ENGiNEER

EXXON CO USA

1555 POYDRAS

NEW ORLEANS, LA 70112

DAVID BULL

AUDUBON INST

6513 CARMEN ST

METAIRIE, LA 70003

GREG BUNCH

AQUARIUM OF AMERICAS

NEW ORLEANS, LA 70148

ANN BURNSIDE

LEASE ANALYST

CNG

1450 POYDRAS

NEW ORLEANS, LA 70112

GEORGE BUTLER III

COUNSEL

CHEVRON

1301 MCKINNEYRM 2256

HOUSTON, TX 77010

DON CAHOON

NWRC

700 CAJUNDOME BLVD.

LAFAYETTE, LA 70506

JACK CALD WELL

GECO-PRAKLA

1325 SOUTH DAIRY ASHFORD

HOUSTON, TX 77077

ART CAL]1X

NWRC

700 CAJUNDOME BLVD.

LAFAYETTE, LA 70506

KATHY CAMP

SALES MANAGER

RACAL NCS INC

3624 WESTCHASE DR

HOUSTON, TX 77042

DON CAMPBELL

ATTORNEY

MARATHON OIL CO

5395 MAIN ST

FINDLAY, OH 45840

KERRY CAMPBELL

FUGRO-MCCLELLAND

6100 HIILLCROFT ST

HOUSTON, TX 77081

JANE CARLSON

CONTRACTING OFFICER

MMS

381 ELDEN ST

HERNDON, VA 20170

JOHN CARUSO

TULANE UNIV

7815 DOMINICAN ST

NEW ORLEANS, LA 70118-3743
SANDRA CATALANOTTO

ORDER ANALYST

CNG

1450 POYDRAS ST

NEW ORLEANS, LA 70112

RAYMOND CAVANAGH

SAIC

1710 GOODRIDGE DR

MCLEAN, VA 22102

DENNIS CHEW

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

JEFF CHILD S

TEXAS A&M

TEXAS A&M CTR COASTAL STUDIES

CORPUS CHRISTI, TX 78412

LYLE CHINKIN

SONOMA TECH [NC

1360 REDWOOD WAY

PETALUMA, CA 94954

JOE CHRISTOPHER

CHIEF ENVIRO ASSESSMENT SECT

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

ROBERT CHURCH

ARCHAEOLOGIST

C+C TECH INC

730 E KALISTE SALOOM RD

LAFAYETTE, LA 70508

JAMES CIMATO

MMS

381 ELDEN ST

HERNDON, VA 20170

JERRY CLARK

NFWF

1120 CONNECTICUT AVE NW

WASHINGTON, DC 20036

RODNEY CLUCK

SOCIOLOGIST

MMS

381 ELDEN ST

HERDON, VA 20170

CARON CODJNA

BIOLOGIST

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

GORDON COE

LAND ADVISOR

SPJRIT ENERGY

14141 SOUTHWEST FREEWAY

SUGARLAND, TX 77478

RODGER COLD WELL

MS DMR

1141 BELL VIEW

BILOXI, MS 39530

SNEED COLLARD

UNIV WEST FLORIDA

UWF - BIOLOGY DEPT

PENSACOLA, FL 32514

SUE COMBS

PROJECT MGR

LITTON

1992 LEWIS TURNER BLVD

FT WALTON BEACH, FL 32547

BARNEY CONGDON

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

517
518

DAVID COOKE

CHIEF RESOURCE STUDIES

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

CARROLL CORDES

NWRC

700 CANJUNDOME BLVD

LAFAYETTE, LA 70506

VINCENT COTTONE

ENVIRON ENGINEER

TEXACO E&P

400 POYDRAS ST

NEW ORLEANS, LA 70130

RICHARD COURTEMANCHE

COASTAL ENVIRON INC

1260 MAIN ST

BATON ROUGE, LA 70802

J. KEITH COUVILLION

LAND MGR

TEXACO E&P

P0 BOX 60252

NEW ORLEANS, LA 70160

DEBORAH CRANS WICK

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70124

BILL CROW

LW. CROW & ASSOC

PU BOX 595235

DALLAS, TX 75359

JAN CULBERTSON

ARTIFICIAL REEF COORD

TEXAS PARKS/WILDLIFE

17629 EL CAMINO REAL

HOUSTON, TX 77058

WENDY DABOVAL

ATTORNEY

TEXACO

400 POYDRAS

NEW ORLEANS, LA 70130

WILLIAM DAUGHDRILL

USCG

EIGHTH COAST GUARD DIST

NEW ORLEANS, LA 70130-3396

LES DAUTERIVE

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

DONALD DAVIS

ADMINISTRATOR

OSRADP

E302 HOWE-RUSSELL

BATON ROUGE, LA 70803

DR. RICK DEFENBAUGH

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

KEN DEJOEN

BP EXPLORATION

P0 BOX 4587

HOUSTON, TX 77210

STEVE DEMUTH

DEMEX

401 WHITNEY AVE

GRETNA, LA 70056

YP DESAI

ENVIRONMENTAL ENGINEER

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123
KEN DESLARZES

BIOLOGIST

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

3. MICHAEL DESMOND

OFFSHORE LAND MUR

COASTAL OIL/GAS CORP

COASTAL TOWER

HOUSTON, TX 77046

CYNTHIA DEWITT

BP

P0 BOX 4587

HOUSTON, TX 77210

DR. BLA[NE DINGER

DIRECTOR EH&S

KERR-MCGEE

16666 NORTHCHASE

HOUSTON, TX 77060

JIM DITTY

LSU - CFI

COASTAL FISHERIES INST

BATON ROUGE, LA 70803

QUENTON DOKKEN

PROJECT MGR

TEXAS A&M

CORPUS CHRISTI CTR COASTAL STD

CORPUS CHRISTI, TX 78412

DAVID DOUGALL

AGIP PETOLEUM

2950 N LOOP WEST

HOUSTON, TX 77092

BRAD DOWDELL

VASTAR RESOURCES INC

15375 MEMORIAL DR

HOUSTON, TX 77095

DANIELLE DOWDY

AQUARIUM OF AMERICAS

NEW ORLEANS, LA 70148

LEONARD DRURY

LAND ASSOCIATE

EXXON

P0 BOX 61707

NEW ORLEANS, LA 70161

JOHN DUFF

ASSOC DIRECTOR

UM - LAW SCHOOL

UNIV OF MISSISSIPPI LAW SCHOOL

UNIVERSITY, MS 38677

CHARLES DUFFY III

COUNSEL

W&T OFFSHORE

3900 N CAUSEWAY

METAIRIE, LA 70002

MICHAEL DUNCAN

ASSOC STAFF SCIENTIST

PLANNING SYSTEMS INC

115 CHRISTIAN LANE

SLIDELL, LA 70458

DAVID DUPLANTIER

COUNSEL

CHEVRON

935 GRAVIER

NEW ORLEANS, LA 70112

CURT EBBESMEYER

PARTNER/OCEANOGRAPHER

EVANS-HAMILTON INC

4608 UNION BAY PLACE

SEATTLE, WA 98103

DAVID EIDSON

SRS TECHNOLOGIES

P0 BOX 625

MANHATTEN BEACH, CA 90266

519
520

WILLIAM EVANS

TEXAS A&M

TEXAS A&M MARiNE ACCOUSTIC LAB

GALVESTON, TX 77551

HAMMOND EVE

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

CARYL FAGOT

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

CHRISTINA FAHY

BIOLOGIST

NMFS

501 W OCEAN BLVD

LONG BEACH, CA 90732

MARK FERNAU

EARTH TECH INC

196 BAKER AVE

CONCORD, MA 01742

DAGMAR FERTEL

BIOLOGIST

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

SCOTT FINNEY

ENVIRON SPECIALIST

ACCULAB

1732 4TH ST

HARVEY, LA 70058

TROY FONTENOT

GIS ANALYST

LA DNR

425 N4TH ST

BATON ROUGE, LA 70808

JON FRANCINE

SRS TECHNOLOGIES

7791 WRUSTYNAJLLN

TUCSON, AZ 85735

JAMES FREDERICK

ENVIRONMENTAL SPECIALIST

UNOCAL/SPIRIT ENERGY

14141 SWFWY

SUGARLAND, TX 77418

ROBERT FRITZ

ATTORNEY

MOBJL

1250 POYDRAS

NEW ORLEANS, LA 70113

NORMAN FROOMER

MMS

1201 ELMWOOD PARK BLVD.

NEW ORLEANS, LA 70123-2394

SANDI FURY

CHEVRON

935 GRAVIER ST

NEW ORLEANS, LA 70112

BENNY GALLA WAY

LGL ECO RESEARCH

1410 CAVITT ST

BRYAN, TX 77801

PAUL GALLOWAY

EMERGENCY PREP/RESP COORD

CHEVRON PROD CO

935 GRAVIER ST

NEW ORLEANS, LA 70112

STEPHANIE GAMBINU

MMS

1201 ELMWWOD PARK BLVD

NEW ORLEANS, LA 70123
JOEL GASPN

NAVAL SURFACE WARFARE CTR

28 COLUMBIA AVE

TAKOMA PARK, MD 20912

ROGER GENTRY

NMFS

NMFS OFFICE OF PROTECTED RES

SILVER SPRING, MD 20910

JOHN GEORGE

DEEP WATER REG REP

CONOCO

400 E KALISTE SALOOM RD

LAFAYETTE, LA 70508

TONY GEORGE

GEOPHYSICIST

C+C TECH INC

730 E KALISTE SALOOM RD

LAFAYETTE, LA 70508

DAVID GETTLESON

CONT SHELF ASSOC

759 PARKWAY ST

JUPITER, FL 33477

RENE GIBSON

GOV AFFMRS MGR

SHELL E&P

PU BOX 2463

HOUSTON, TX 77252

BOB GILLARD

ENVIRON SCIENTIST

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

DAVID GISCLAIR

GOVERNOR'S OFFICE

1885 WOODDALE BLVD

BATON ROUGE, LA 70806

521

ROBERT GISINER

NAVAL RESEARCH

800 NORTH QUNCY ST

ARLINGTON, VA 22217

GREG GITSCHLAG

NMFS

4700 AVENUE U

GALVESTON, TX 77551

ANDERSON GITTENS

RIKE SERVICE INC

P0 BOX 13786

NEW ORLEANS, LA 70185

ANGIE CiOBERT

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

GARY GOEKE

MMS

PENSACOLA, FL

DR. YtJRY GOLUBEV

FLORIDA STATE UNIV

FSU

TALLAHASEE, FL 32306

KEITH GOOD

PHYSICAL SCIENTIST

MMS

381 ELDEN ST

HERNDON, VA 20170

DR. GERALD GRAU

ASST CTR DIRECTOR

USGS

700 CAJ1JNDOME BLVD

LAFAYETTE, LA 70506
522

DEBORAH GREEN

PROJ MANAGER

SFSU

1600 HOLLOWAY AVE HH222

SAN FRANCISCO, CA 94114

ROBERT GRIFFIN

MOTE

1600 KEN THOMPSON PRXWY

SARASOTA, FL 34236-1096

EMMA GRIGG

FIELD COORD

SFSU

1600 HOLLOWAY HH222

SAN FRANCISCO, CA 94132

GEORGE GUILLEN

OCEANOGRAPHER

MMS

1201 ELMWOOD PARK

NEW ORLEANS, LA 70123

NORM GUINASSO

GEOCHEMIENVIRON RESEARCH

727 GRAHAM RD

COLLEGE STATION, TX 77845

LYNNE HACKED ORN

LAND MANAGER

SONAT EXPLORATION

P0 BOX 4792

HOUSTON, TX 77046

PETER HAMILTON

SCIENCE APP INTL

615 OBERLIN RD

RALEIGH, NC 27605

GEORGE HAMPTON

SR ENVIRON SCIENTIST

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

ROSE HAMPTON

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

LARRY HANDLEY

NWRC

700 CAJUNDOME BLVD

LAFAYETTE, LA 70506

JOHN HANES

LANDMAN

EXXON

P0 BOX 4778

HOUSTON, TX 77210

JIM HANIFEN

PRGM MANAGER

LA DWF

P0 BOX 98000

BATON ROUGE, LA 70898

JEFF HARRIS

COASTAL RESOURCES COORDINATOR

LDNRICMD

PU BOX 44487

BATON ROUGE, LA 70804

VIRGIL HARRIS

EXEC DIRECTOR

OOC

P0 BOX 50751

NEW ORLEANS, LA 70150

ADELE HARTRICK

LANDMAN

KERR-MCGEE

16666 NORTHCHASE

HOUSTON, TX 77060

EIGORO HASHIMOTO

USM

5044-B BEATL1NE RD

LONG BEACH, MS 39560
PAUL HAYS

TEXACO

4800 FORNACE

BELLAIRE, TX 77401

DOUG HEAT WOLE

MGR

ECO & ENVIRON iNC

316 S BAYLEN #540

PENSACOLA, FL 32501

GREG HEMPEN

COE

ST. LOUIS, MO 63103

LARRY HENRY

SR ENVIRON ADVISOR

CHEVRON

935 GRAVIER ST

NEW ORLEANS, LA 70112

DIRK F]ERKHOF

MMS

381 ELDEN ST

HERNDON, VA 20170

NANCY HESS

UW-MADISON

UW MADISON DEPT WILDLIFE ECOL

MADISON, WI 53706

EMMA HICKERSON

RESEARCH COORD

NMS

216 W 26TH ST

BRYAN, TX 77803

CHARLES HILL

MMS

1201 ELMWOOD BLVD

NEW ORLEANS, LA 70123

MAURICE HILL

ENVIRON SCIENTIST

MMS

770 PASEO CAMARILLO

CAMARILLO, CA 93010

PETER HILL

W.H. LINDER AS SOC

3330 W ESPLANADE AVE

METAIRIE, LA 70002

ROBERT HOFMAN

MARINE MAMMAL COMM

4340 EAST WEST HWY

BETHESDA, MD 20814

SAMUEL HOLDER

MMS

1201 ELMWOOD PARK BLVD.

NEW ORLEANS, LA 70123

KEN HOLLINGSHEAD

NMFS

1355 EAST-WEST HWY

SILVER SPRING, MD 02543

TERRY HOLMAN

PROGRAM MANAGEMENT OFFICER

MMS

DEPT INTERIOR MMS 1849 C ST

WASHINGTON, DC 20240

CHUCK HOPSON

MMS

1201 ELMWOOD PARK BLVD.

NEW ORLEANS, LA 70123-2394

JERALD HORST

AREA AGENT

SEA GRANT EXT PRGM

1855 AMES BLVD

MARRERO, LA 70072

523
524

S.A. HSU

PROFESSOR

LSU

308 HOWE-RUSSELL BLDG

BATON ROUGE, LA 70803

DAVID HUGHES

ASSOC PROFESSOR

LSU

101 AGR-ADMIIN BLDG

BATON ROUGE, LA 70803

NICOLETTE HEJMPHRIES

MMS

1849 C STREET NW

WASHINGTON, DC 20240

JAMES HUNT

LANDMAN

MURPHY E&P CO

BOX 61780

NEW ORLEANS, LA 70161

JACK IRION

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

KERRY IRISH

MARINE MAMMAL RES GRP

VICTORIA,

MASAKI ISHIKAWA

RIKE SERVICE INC

P0 BOX 13786

NEW ORLEANS, LA 70185

WILLIAM JACKSON

NMFS

4700 AVENUE U

GALVESTON, TX 77551

MELANIE JARRELL

ENVIRON COORD

OCEAN ENERGY

3861 AMBASSADOR CAFFERY

LAFAYETTE, LA 70503

MICHAEL JASNEY

NRDC

6310 SAN VINCENTI BLVD

LOS ANGELES, CA 90048

WEBB JAY

LAND REP

TEXACO

400 POYDRAS

NEW ORLEANS, LA 70123

CLINTON JESKE

NWRC

700 CANJTJNDOME BLVD

LAFAYETTE, LA 70506

CHERIE JOHNSON

MIIVIS

NEW ORLEANS, LA 70123

DONALD JOHNSON

NAVAL RESEARCH LAB

NAVAL RESEARCH LAB

STENNIS SPACE CTR, MS 39529

WALTER JOHNSON

OCEANOGRAPHER

MMS

381 ELDEN ST

HERNDON, VA 20170

JAMES JOHNSTON

NWRC

700 CAJUNDOME BLVD

LAFAYETTE, LA 70506
VITA JONES

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

WILLIAM JONES

NWRC

700 CAJTJNDOME BLVD

LAFAYETTE, LA 70506

LAURIE JUGAN

SR SCIENTIST

PLANNING SYS INC

MSAAT BLDG 9121

STENNIS SPACE CTR, MS 39529

RONNIE KAIVIPER

BP EXPLORATION

P0 BOX 4587

HOUSTON, TX 77210

RICK KASPRZAK

ARTIFICJAL REEF COORD

LA DWF

PU BOX 98000

BATON ROUGE, LA 70898

SEAN KEENAN

LSU

LSU BIOLOGICAL SCIENCES INST

BATON ROUGE, LA 70803

TONY KEEVIN

COE

1222 SPRUCE ST

ST LOUIS, MO 63103

EDWARD KEITH

NOVA SE UNIV

3200 S UNIVERSITY DRIVE

FT LAUDERDALE, FL 33328

KEVIN KELLEY

RIKE SERVICE INC

P0 BOX 13786

NEW ORLEANS, LA 70185

FRANK KELLY

GEOCHEM/ENVIRON RESEARCH

727 GRAHAM RD

COLLEGE STATION, TX 77845

JAMES KENDALL

CHIEF ENVIRON STUDIES SECTION

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

JOHN KENNY

MGR

DEMEX

401 WHITNEY AVE

GRETNA, LA 70056

DARLENE KETTEN

WOODS HOLE

11 SCHOOL ST

WOODS HOLE, MA 02543

TIM KILLEEN

COASTAL RESOURCES COORD

LA DNR

1600 CANAL ST

NEW ORLEANS, LA 70112

JACK KINDINGER

USGS

600 FOURTH ST SOUTH

ST PETERSBURG, FL 3370 1-4802

LAURA KLAHRE

OCEANOGRAPHER

MMS

381 ELDEN ST

HERNDON, VA 22070

525
526

GAIL KORENAGA

ENVIRON TOXICOLOGIST

CHEVRON

BOX 1627

RICHMOND, CA 94802

BONNIE LABORDE JOHNSON

ENVIRON SPECIALIST

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

JIM LAFEVERS

REGLATORY ADVISOR

UNION PACiFIC RES

FORT WORTH, TX

RON LAI

MMS

381 ELDEN ST

HERNDON, VA 22070

JOEY LANDRENEAU

QST ENVIRONMENTAL

BOX 1703

GAiNESVILLE, FL 32602-1703

CONNIE LANDRY

ENVIRON STUDIES PRM SPECIALIST

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

LAURA LANDRY

PRESIDENT

L.A. LANDRY ASSOC

105 BAYOU VISTA DRIVE

HITCHCOCK, TX 77562

WILLIAM LANG

MMS

1201 ELMWOOD PARK BLVD.

NEW ORLEANS, LA 70123

TROY LANICH

AIRLAW ENFORCEMENT PILOT

USCG

7926 GRIZZLEY

CORPUS CHRISTI, TX 78414

JAMES LARRE

LAND REP

CHEVRON

935 GRAVIER ST

NEW ORLEANS, LA 70112

STEVE LEDET

REGULATORY ADVISOR

MOBIL

1250 POYDRAS

NEW ORLEANS, LA 70113

GRIFF LEE

CONCULTANT

GRIFF C. LEE iNC

6353 CARLSON DR

NEW ORLEANS, LA 70122

ANN LEHMAN

701 POYDRAS ST

NEW ORLEANS, LA 70139

DAVID LEIDEL

HALIBURTON ENERGY

8432 SOUTH 1-35W

ALVARADO, TX 75009

ERWIN LEON

RIKE SERVICE INC

P0 BOX 13786

NEW ORLEANS, LA 70185

GIA LEPERE

OPS ASSIST

MATRIX OIL/GAS

PU BOX 2468

CUVINGTON, LA 70434
MIKE LETS ON

BIOLOGIST

ECOL & ENVIRON INC

316 S BAYLOR ST

PENSACOLA, FL 32501

SUSAN LIBIEZ

PERMIT SPECIALIST

CHEVRON

935 GRAVIER ST

NEW ORLEANS, LA 701 12

STEVE LITTLE

EXXON CO USA

1555 POYDRAS ST

NEW ORLEANS, LA 70112

TONY LITTLEJOHN

DI SUPERVISOR

EXXON

1555 POYDRAS ST

NEW ORLEANS, LA 70112

ALEXIS LUGO-FERNANDEZ

MMS

1201 ELMWOOD PARK BLVD.

NEW ORLEANS, LA 70123

MOLLY LUTCAVAGE

NEW ENGLAND AQUARIUM

1 CENTRAL WHARF

BOSTON, MA 02110

HARRY LUTON

MMS

1201 ELMWOOD PARK BLVD.

NEW ORLEANS, LA 70123

MIKE LYONS

MGR ENVIRON AFFAIRS

LA MID CONTINENT

801 NORTH BLVD #201

BATON ROUGE, LA 70802

IAN MACDONALD

GEOCHEMIENVIRON RESEARCH

833 GRAHAM RD

COLLEGE STATION, TX 77845

JOSEPH MANISCALCO

MANAGER LAND/ACQUISITIONS

TAYLOR ENERGY CO

944 ST CHARLES AVE

NEW ORLEANS, LA 70130

BRIAN MARCKS

BIOLOGIST

LDNRICMD

625 N 4TH ST

BATON ROUGE, LA 70810

ANTHONY MARINO

ATTORNEY

SCHULLYROBERTS SLATTERY

JAUBERT AND MARINO

NEW ORLEANS, LA 70163

KAREN MARTIN

ADMIN ASSIST

EXXON CO.

1555 POYDRAS

NEW ORLEANS, LA 70112

LUIS MARTINEZ

PiKE SERVICE INC

P0 BOX 13786

NEW ORLEANS, LA 70185

DREW MAYERSON

MMS

770 PASEO CAMARILLO

CAMARILLO, CA 93010

DIANE MAYO

LAND ANALYST

TEXACO

P0 BOX 60252

NEW ORLEANS, LA 70160

527
528

KATHERINE MAZE

FISHERIES BIOLOGIST

JOHNSON CONTROLS

3209 FREDERIC ST

PASCAGOULA, MS 39567

ERIC MEINDL

DIVISION CHIEF, NOAA

BLDG 1100

STENNIS SPACE CTR, MS 39529

RICHARD MEYER

SHELL OFFSHORE

BOX 61933

NEW ORLEANS, LA 70161

THOMAS MEYER

GEOLOGIST/TECH SPEC

X-CHEM

7601 WILSON ST

HARAHAN, LA 70123

BOB MIDDLETON

CHIEF OF STAFF

MMS

1849 C STNW

WASHINGTON, DC 20240

JOHN MILIO

MMS

6620 SOUTHPOINT DR SOUTH

JACKSONVILLE, FL 32216-0958

MARY ANN MILOSAVICH

INTL. PROGRAMS SPECIALIST

MMS

381 ELDEN ST

HERNDON, VA 20170-48 17

BOB MINK

DEPUTY DIRECTOR

GEO SURVEY ALABAMA

420 HACKBERRY LN

TUSCALOOSA, AL 35486

ARTHUR MITCHELL

COUNSEL

CHEVRON

935 GRAVIER ST

NEW ORLEANS, LA 70112

R. SCOTT MONROE

AEGIS SHOCK TRIAL MGR

U.S. NAVY

2531 JEFFERSON DAVIS HWY

ARLINGTON, VA 22202

PAUL MONTAGNA

UT MARINE SCI INST

P0 BOX 1267

PORT ARANSAS, TX 78373

TARA MONTGOMERY

GEOGRAPHER

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70121

DAVID MOORE

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

BOB MORAN

DIRECTOR GOV!T AFFAIRS

NOIA

1120 GSTNW

WASHINGTON, DC 20005

DAVE MORAN

ENVIRON SPECIALIST

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

MICHELLE MORIN

MMS

1201 ELMWOOD PARK BLVD.

NEW ORLEANS, LA 70123-2394
FRANK MULLER-KARGER

UNIV SOUTH FLORIDA

USF DEPT MARINE SCIENCE

ST PERTERSBURG, FL 33701

JOSEPH MULLIN

MMS

381 ELDEN ST

HERNDON, VA 20170

KEITH MULLIN

NMFS

P0 DRAWER 1207

PASCAGOULA, MS 39568

CHRISTINA MYLES-TOCHKO

JOHNS HOPKINS UNIV

APPLIED PHYSICS LAB

LAUREL, MD 20723-6099

LINDSAY NAKASMIMA

COASTAL ENVIRON INC

1260 MAIN ST

BATON ROUGE, LA 70802

JAMES NIEMANN

SHALLOW HAZARD TEAM LEADER

CHEVRON USA

935 GRAVIER ST

NEW ORLEANS, LA 70112

JEFFREY NORRJS

TEXAS A&M

TEXAS A&M DEPT MARINE BIOLOGY

GALVESTON, TX 77553

WORTH NOWLIN

TEXAS A&M

TEXAS A&M DEPT OF OCEANOGRAPHY

COLLEGE STATION, TX 77843

ARLETTE NIJNEZ

SHELL DEEP WATER

P0 BOX 61933

NEW ORLEANS, LA 70161

DAVID OGET

LA DEQ

3501 CHATEAU BLVD

KENNER, LA 70065

JOEL ORTEGA

TEXAS A&M UNIV

DEPT OF MARINE BIOLOGY

GALVESTON, TX 77553-1675

JANET OSBORNE

HOSPICE OF ACADIANA

212 LAKESIDE

LAFAYETTE, LA 70508

NEIL OSBORNE

VICE PRESIDENT

AIR LOGISTICS

4605 INDUSTRTAL DRIVE

NEW IBERIA, LA

CHRIS OYNES

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

BILL PANISZCZYN

TRACOR SYS TECH

2611 JEFFERSON DAVIS HWY

ARLINGTON, VA 22202

MICHAEL PARKER

SR STAFF ENGINEER

EXXON CO USA

P0 BOX 2180

HOUSTON, TX 77252

529
530

WANDA PARKER

MGR

P0 BOX 2880

DALLAS, TX 75221

CHRISTY PATTENGILL

520 DELAVINA

SANTA BARBARA, CA 93101

G PEGGIOW

COAM

BLDG 103

STENNIS SPACE CTR, MS 39529

HARRIET PERRY

GULF COAST RES LAB

P0 BOX 7000

OCEAN SPRINGS, MS 39566

JOE PERRYMAN

ENVIRON PROTECTION SPECIALIST

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

ELIZABETH PEULER

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70124

NEAL PHILLIPS

CONT SHELF ASSOC

64 CEDAR AVE

TOWSON, MD 21286

FRANK PICCOLO

UNOCAL OIL/GAS

402 1-4023 AMB CAFFERY PKWY

LAFAYETTE, LA 70593

MARK PIERSON

MMS

MMS

CAMARILLO, CA 93010

CLAY PIL]E'

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

MOE PLAISANCE

DIAMOND OFFSHORE

1451 KATY FREEWAY

HOUSTON, TX 77094

BILLY POE

PRESIDENT

EXPLOSIVE SVCS

BOX 45742

BATON ROUGE, LA 70895

CAROL PULLEN

REGULATORY SPECIALIST

EXXON CO USA

P0 BOX 61707

NEW ORLEANS, LA 70065

GAIL RA1NEY

OCEANOGRAPHER

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

JAMES RANDOLPH

NMFS

4700 AVENUE U

GALVESTON, TX 77551

TOM RANDOLPH

CONSULTANT

RANDOLPH CONSULTING

P0 BOX 82860

BATON ROUGE, LA 70884

J.T. RAULS

COUNSEL

EXXON

233 BENMAR

HOUSTON, TX 77060
JIM RAY

ENVIRON SCIENCE MGR

EQUILON\SHELL

SPRING, TX 77379

JIM REGG

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70124

VILLERE REGGIO

RECREATION PLANNER

MMS

1524 PEACH ST

METAIRIE, LA 70001

RONALD RENHARDT

MCMORAN OIL/GAS

1615 POYDRAS ST

NEW ORLEANS, LA 70112

CR. REWERTS

LAND REP

CHEVRON

935 GRAVIER ST

NEW ORLEANS, LA 70112

JULIE REYNOLDS

MMS

381 ELDON ST

HERNDON, VA 20170

MIKE RICH

MANAGER

PLANNING SYS INC

115 CHRISTIAN LANE

SLIDELL, LA 70458

CARVER RICHARDS

PHILIPS PETROLEUM

P0 BOX 1967

HOUSTON, TX 7725 1-1967

ED RICHARDSON

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70124

W. JOHN RICHARDSON

LGL ENVIRON RES ASSOC

P0 BOX 280

ONTARIO CANADA, L7B 1A6

TERRY RIGGS

TEXAS A&M

TEXAS A&M CTR COASTAL STUDIES

CORPUS CHRISTI, TX 78412

J.L. RIKE

RIKE SVC INC

P.O. BOX 13786

NEW ORLEANS, LA 70185

TOM RIPPETOE

MGR CASED HOLE WELLWORK

CHEVRON

CHEVRON

LAFAYETTE, LA 70596

KELLY ROBERTS

SR ENVIRON COORD

CONOCO

600 E. KALISTE SALOOM

LAFAYETTE, LA 70505

LARRY ROBERTS

MMS

381 ELDON ST

HERNDON, VA 20170

PAUL ROBERTS

SONOMA TECH INC

1360 REDWOOD WAY

PETALUMA, CA 94954-1169

531
532

TEDDY RODAS

DIVER

216 MONARCH DR

HOUMA, LA 70364

CAROL RODEN

BIOLOGIST

NMFS

3209 FREDERIC ST

PASCAGOULA, MS 39563

CLAUDIA ROGERS

MMS

1201 ELMWOOD PARK BLVD.

NEW ORLEANS, LA 70123

ROBERT ROGERS

MMS

1201 ELMWOOD PARK BLVD.

NEW ORLEANS, LA 70123

ERIK ROMERO

LAND ADVISOR

MOBIL

1250 POYDRAS

NEW ORLEANS, LA 70113

BUTCH ROMMEL

FLA DEP

MMPL FDEQ

ST PETERSBURG, FL 33711

TERRY ROONEY

BP EXPLORATION

P0 BOX 4587

HOUSTON, TX 77210

PASQUALE ROSCIGNO

MMS

1201 ELMWOOD PARK BLVD.

NEW ORLEANS, LA 70123

MARK ROUSE

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

MICHELLE ROY

UNIV OF W. FLA

11000 UNIVERSITY PKWY

PENSACOLA, FL 32514

STEVE RUBB

GEOGRAPHER

USGS

1 SABINE ISLAND DR

GULF BREEZE, FL 32561

BOB RUSSELL

LSU

LSU MIJSEUM OF ZOOLOGY

BATON ROUGE, LA 70893

JANE RUT

PROJECT MANAGER

TECH RESP PLANNING CORP

4201 F.M. 1960 WEST

HOUSTON, TX 77068

BRIAN SANDERS

VASTAR RESOURCES

15375 MEMORIAL

HOUSTON, TX 77079

SCOTT SANDORT

RESOURCE CONS V. OFFICER

NMFS

1 BLACKBURI' DR

GLOUCESTER, MA 01930

KENT SATTERLEE

ENVIRON ENGINEER

SHELL OFFSHORE

P0 BOX 61933

NEW ORLEANS, LA 70471
JOE SAWYER

EHS MGR

MOBIL

1230 POYDRAS

NEW ORLEANS, LA 70113

DAVID SCALFANO

ENGINEER

NORTHLAKE ENGINEERS

1011 N CAUSEWAY BLVD

MANDEVILLE, LA 70471

DOUGLAS SCALLY

NDBC

NDBC

STENNIS SPACE CTR, MS 39529

ANN SCARBOROUGH BULL

IVIMS

1201 ELMWWOD BLVD

NEW ORLEANS, LA 70123

HELENA SCHAEFER

NWRC

700 CAJUNDOME BLVD

LAFAYETTE, LA 70506

C.D. SCHEMPF JR.

KC OFFSHORE LLC

36499 PERKINS RD

PRAIRIEVILLE, LA 70769

ROB SCHICK

GRAD STUDENT

DUKE UNIVERSITY

7A BRANDYWINE CT

DURHAM, NC 27705

DON SCHIRO

CHEVRON

935 GRAVIER ST

NEW ORLEANS, LA 70112

BILL SCHMIDT

MAR INC

P0 BOX 473

ATLANTIC HIGHLAND, NJ 07716

KATE SCHMIDT

TRACOR SYS TECH

2611 JEFFERSON DAVIS HWY

ARLINGTON, VA 22202

MIKI SCHMIDT

NOAA

2234 SOUTH HOBSON AVE

CHARLESTON, SC 29405

TERRY SCHOLTEN

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

WILLIAM SCHROEDER

DAUPHIN ISLAND SEA LAB

PU BOX 369-3 70

DAUPHIN ISLAND, AL 36528

TONY SEBASTIAN

6889 CATINA ST

NEW ORLEANS, LA 70124

CHRISTIAN SEIFERT

CRM SPECIALIST

DNR

625 N 4TH ST

BATON ROUGE, LA 70802

JOHN SEIP

AMOCO PRODUCTION CO

1340 POYDRAS

NEW ORLEANS, LA 70112

533
534

ARVIND SHAH

ENGiNEER

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

BRIAN SHANNON

ARCO RESEARCH

2300 W PLANO PKWY

PLANO, TX 75075

RICHARD SHAW

DIRECTOR

COASTAL FISERIES INST

LSU

BATON ROUGE, LA 70803

GERALD SHEARER

GEOLOGIST

MMS

949 E 36TH AVE

ANCHORAGE, AK 99508

MARK SHRIMPTON

COMM RESOURCES SVCS

P0 BOX 5936

CANADA,

JOHN SIGURDSON

SPAWARSYSCEN

SPA WARSYSCEN

SAN DIEGO, CA 92 152-6505

ROBERT SIMMONS

SIMMONS CONSULTING

1418 LAKE VILLAGE BLVD

SLIDELL, LA 70461

RAYMOND SIMONEAUX

CHEVRON

935 GRAVIER ST

NEW ORLEANS, LA 70112

WILL SLOGER

NAVAL FACILITIES

2155 TRACKER

N. CHARLESTON, SC 29406

MICHAEL SMITH

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

DAVID SNYDER

CONT SHELF ASSOC

759 PARKWAY ST

JUPITER, FL 33477

JEDD SONDERGARD

MMS

1201 ELM WOOD PARK BLVD.

NEW ORLEANS, LA 70123

ALAN SPACKMAN

DIRECTOR OFFSHORE

IADC

P0 BOX 4287

HOUSTON, TX 77210-4287

RICK SPAULDING

OGDEN ENVIRON

1 EAST ANAPAMU

SANTA BARBARA, CA 93101

DAVID STANLEY

CCEER

LSU

BATON ROUGE, LA 70803

KENT STAUFFER

PETRO ENGINEER

MMS

1201 ELMWOOD BLVD

NEW ORLEANS, LA 70123
WILLIAM STEORTS

DIRECTOR ENVIRON PROGRAM

ENSCO [NC

445 PINEDA COURT

MELBOURNE, FL 32940

BOB STEWART

PRESIDENT

NOIA

1120 G ST NW

WASHINGTON, DC 20005

SCOTT STOERMER

USCG

800 DAVID DR

MORGAN CITY, LA 70380

KEITH STOREY

COMM RESOURCES SVCS

P0 BOX 5936

CANADA,

MICHAEL STRIKMILLER

MARKETING MANAGER

ENVIRON ENTERPRISES USA

58485 PEARL ACRES ROAD

SLIDELL, LA 70461

KENNETH SULAK

BRANCH CHIEF - EST\COASTAL ECO

FL/CARIBB SCI CTR

7920 NW 71ST ST

GAINESVILLE, FL 32653

DENNIS SUSTALA

SR REG COMP COORD

VASTAR INC

15375 MEMORIAL DR

HOUSTON, TX 77079

DAVID SZABO

FUGRO GEOS

P0 BOX 740010

HOUSTON, TX 77274

TAIR TAIROV

lUKE SERVICE [NC

P0 BOX 13786

NEW ORLEANS, LA 70185

MARK TASKER

NATURE CONSV COMM

DIJNNET HOUSE

ABERDEEN SCOTLAND, AB1O 1UZ

NICK TEW

GIS CHIEF

GEO SURVEY - ALABAMA

420 HACKBERRY LN

TUSCALOOSA, AL 35486

ELLEN THOMAS

CHEVRON

935 GRAVIER ST

NEW ORLEANS, LA 70112

SHERL-LrN THOMAS

MARKETING DIRECTOR

TRP

4201 FM 1960 W

HOUSTON, TX 77068

PHILIP THORSON

SRS TECHNOLOGIES

7973 PEACH POINT AVE

SAN DIEGO, CA 92126

WILFRED TIMES

VISUAL INFO SPEC

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

TOM TODD

LAND ADVISOR

UNOCAL

P0 BOX 4551

HOUSTON, TX 77281

535
536

MICHAEL TOLBERT

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

KAREN VANACOR

REGULATORY ADVISOR

MOBIL OIL

1250 POYDRAS BLDG

NEW ORLEANS, LA 70113

JAMIE VAZQUEZ

LAND MANAGER

W&T OFFSHORE

3900 N CAUSEWAY

METAIRIE, LA 70002

PETER VELEZ

MGR REGULATORY AFFAIRS

SHELL OFFSHORE

P0 BOX 61933

NEW ORLEANS, LA 70161

PAUL VERSOWSKI

CHEVRON

935 GRAVIER ST

NEW ORLEANS, LA 70112

GERALD VETTER

SR. ENGINEER

WALDEMAN/NELSON & CO

1200 ST CHARLES AVE

NEW ORLEANS, LA 70115

DEBRA VIGIL

MMS

1201 ELMWOOD PARK BLVD.

NEW ORLEANS, LA 70123

KATHY VIGNESS

MARINE ACOUSTIC INC

901 NORTH STUART

ARLINGTON, VA 22203

PINKY VINSON

PETROPHYSICIST

BP

200 WEST LAKE BLVD

HOUSTON, TX 77079

LISA VITALE

TEXAS A&M

TEXAS A&M CTR COASTAL STUDIES

CORPUS CHRISTI, TX 78412

PHTLLIP VONDULLEN

CHEVRON

935 GRAVIER ST

NEW ORLEANS, LA 70112

STEVE WADDELL

MMS

1201 ELMWOOD PARK BLVD.

NEW ORLEANS, LA 70123-23 94

VAN WADDELL

SAIC

615 OBERLIN ROAD

RALEIGH, NC 27605

MICHAEL WAGUESPACK

PROJECT MANAGER

WALK HAYDEL

600 CARONDELET

NEW ORLEANS, LA 70130

CHARLENE WALK

ENGINEER

EXXON

1555 POYDRAS ST

NEW ORLEANS, LA 70112

DONALD WALKER

LAND ADVISOR

MOBIL

1250 POYDRAS

NEW ORLEANS, LA 70113
BARBARA WALLACE

PROJECT MGR

TECHLAW iNC

4340 EAST WEST HWY

BETHESDA, MD 20814

MIKE WALLACE

ENVIRON PROTECTION SPEC

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

STEVE WALTON

VICE PRESIDENT- ENGINEERING

MATRIX OIL/GAS

P0 BOX 2468

COVrNGTON, LA 70065

SKIP WARD

TEXAS A&M

1200 MARINER DRIVE

COLLEGE STATION, TX 77845

BENJAMINE WARING

PRESIDENT, WARING AND ASSOC

842 ELM WOOD PARK BLVD

NEW ORLEANS, LA 70123

LINDA WAYNE

LA GIS COUNCIL

300 HOWE-RUSSELL

BATON ROUGE, LA 70803

DOUG WEAVER

FISH BIOLOGIST

FL/CARIBB SCI CTR

7920 NW 71ST ST

GAINESVILLE, FL 32653

FRANK WENDLING

WILDLIFE BIOLOGIST

MMS

949 EAST 36TH AVE

ANCHORAGE, AK 99508

NICK WETZEL

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

MICHAEL WHITEHEAD

MAR INC

3007 LEISURE TIME DR

DIAMONDHEAD, MS 39525

JIM WIGGINS

LANDMAN

AVIAVA ENERGY

P0 BOX 1350

HOUSTON, TX 77251

JON WILCOX

LANDMAN, MARATHON OIL

P0 BOX 3128

HOUSTON, TX 77253

GREGORY WILLIAMS

PROCESSING TECH

CHEVRON

935 GRAVIER ST

NEW ORLEANS, LA 70113

ANNE WILSON

LEASE ANALYST

STONE ENERGY CORP

P0 BOX 52807

LAFAYETTE, LA 70505

JUDY WILSON

MARINE BIOLOGIST

MMS

381 ELDEN ST

HERNDON, VA 20170

TONY WILTZ

LAND ADVISOR

SPIRIT ENERGY 76

BOX 39200

LAFAYETTE, LA 70503

537
538

MARK WITTEN

REGULATORY ADVISOR

CHEVRON USA

935 GRAVIER ST

NEW ORLEANS, LA 70112

JOHN WORMOUTH

TEXAS A&M

TEXAS A&M UNIV

COLLEGE STATION, TX 77843

BERND WEJRSIG

TEXAS A&M UNIV

DEPT OF MARiNE BIOLOGY

GALVESTON, TX 77553-1675

FRANK YAM

PETRO ENGINEER

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

MARK YOCKE

ENVIRON

101 ROWLAND WAY

NOVATO, CA 94945-5010

GREGORY YORK

LANDMAN

PHILLIPS PETROLEUM

P0 BOX 1967

HOUSTON, TX 77452

TOM YOURK

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

VICKI ZATARAIN

ECONOMIST

MMS

1201 ELMWOOD PARK BLVD

NEW ORLEANS, LA 70123

STEVE ZIMAN

CHEVRON

100 CHEVRON WAY

RICHMOND, CA 94804

DAVID Z[NZER

GEOPHYSICIST

MMS

381 ELDEN ST

HERNDON, VA 20170

A1'NE ZOIDIS

MARiNE BIOLOGIST

TETRA-TECH

180 HOWARD ST

SAN FRANCISCO, CA 94105
The Department of the Interior Mission 

As the Nation's principal conservation agency, the Department of the Interior has responsibility for 

most of our nationally owned public lands and natural 

resources. This includes fostering sound use of 

our 

land and water 

resources; protecting our fish, wildlife, and biological diversity; preserving the 

environmental and cultural values of our national parks and historical places; and providing for the 

enjoyment of life through outdoor recreation. The Department assesses our energy and mineral 

resources and works to ensure 

that their development is in the best interests of all our people by 

encouraging stewardship and citizen participation in their care. The Department also has a major 

responsibility for American Indian reservation communities and for people who live in island territories 

under U.S. administration. 

The Minerals Management Service Mission 

As a bureau of the Department of the Interior, the Minerals Management Service's (MMS) primary 

responsibilities are to manage the mineral 

resources 

located on the Nation's Outer Continental Shelf 

(OCS), collect revenue from the Federal OCS and onshore Federal and Indian lands, and distribute 

those 

revenues. 

Moreover, in working to meet its responsibilities, the Offshore Minerals Management Program 

administers the OCS competitive leasing program and oversees the safe and environmentally sound 

exploration and production of our Nation's offshore natural gas, oil and other mineral 

resources. The 

MMS Royalty Management Program meets its responsibilities by ensuring the efficient, timely and 

accurate collection and disbursement of 

revenue 

from mineral leasing and production due to Indian 

tribes and allottees, States and the U.S. Treasury. 

The MMS strives to fulfill its responsibilities through the general guiding principles of: (1) being 

responsive to the public's concerns and interests by maintaining a dialogue with all potentially affected 

parties and (2) carrying out its programs with an emphasis on working to enhance the quality of life for 

all Americans by lending MMS assistance and expertise to economic development and environmental 

protection.