OCS Study

MMS 2001-039

Gulf of Mexico

Marine Protected Species Workshop

June 1999

U.S. Department of the Interior

Minerals Management Service

Gulf of Mexico OCS Region
U.S. Department of the Interior

Minerals Management Service

Gulf of Mexico OCS Region

OCS Study

MMS 2001-039

Gulf of Mexico

Marine Protected Species Workshop

June 1999

Editors

Melanie McKay

Judith Nides

William Lang

Debra Vigil

Prepared under MMS Contract

14-35-0001-30665

by

University of New Orleans

Office of Conference Services

New Orleans, Louisiana 70814

Published by

New Orleans

May 2001
iii

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 signify 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., J. Nides, W. Lang, and D. Vigil. 2001. Gulf of Mexico Marine Protected Species

Workshop, June 1999. U.S. Dept of the Interior, Minerals Management Service, Gulf of Mexico

OCS Region, New Orleans, La. OCS Study MMS 2001-039. 171 pp.
v

TABLE OF CONTENTS

LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii

ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

BACKGROUND

INTRODUCTION

Dr. William Lang and Ms. Dagmar Fertl ......................................1

ELEMENTS OF STUDIES OF PROTECTED SPECIES IN THE GULF OF MEXICO:

HISTORY, PHILOSOPHY, AND RESEARCH

Dr. William E. Evans .....................................................8

THE MARINE MAMMAL PROTECTION ACT

Dr. Robert Hofman . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

THE ENDANGERED SPECIES ACT AND GULF OF MEXICO MARINE SPECIES

Mr. David Bernhart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

BIOLOGY

GULFCET I AND II – CETACEANS, SEA TURTLES AND HABITAT

CONSIDERATIONS

Dr. Keith D. Mullin and Dr. Randall W. Davis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

MANATEES IN THE GULF OF MEXICO

Dr. Robert K. Bonde and Dr. Lynn W. Lefebvre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

SEA TURTLES OF THE GULF OF MEXICO

Dr. Maurice L. Renaud . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

INDUSTRY: MAN-MADE AND NATURAL ACTIVITY IMPACTS ON MARINE

MAMMALS AND SEA TURTLES

MMS AND DEEPWATER ACTIVITIES

Mr. Jim Regg and Mr. B.J. Kruse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
vi

OFFSHORE PRODUCTION OPERATIONS: AN OVERVIEW OF GULF

OF MEXICO OCS OIL AND GAS OPERATIONS

Ms. Sandra M. Fury . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

ACOUSTIC ACTIVITIES OF THE SEISMIC INDUSTRY

Dr. Jack Caldwell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

BIOLOGICAL IMPACTS OF UNDERWATER EXPLOSIVES USED IN

PLATFORM SALVAGE IN THE GULF OF MEXICO

Mr. Gregg Gitschlag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

NAVY EXPLOSIVES TESTING

Mr. William Sloger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

HUMAN ACTIVITIES AND NATURAL EVENTS: IMPACTS ON

GULF OF MEXICO MARINE MAMMALS, PART 1

Dr. Bernd Würsig . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

HUMAN ACTIVITIES AND NATURAL EVENTS: IMPACTS ON

GULF OF MEXICO MARINE MAMMALS, PART 2

Dr. Jeffery Norris . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

HUMAN ACTIVITIES AND NATURAL EVENTS: IMPACTS ON

GULF OF MEXICO SEA TURTLES

Dr. David Owens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

REVIEW OF RELATED RESEARCH AND MONITORING PROGRAMS

ROLE OF A NON-GOVERNMENTAL IN GULF PROTECTED SPECIES CONCERNS

Ms. Sharon Young . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

MARINE MAMMAL STRANDING NETWORKS AND ENVIRONMENTAL

CONTAMINANTS

Dr. Teri Rowles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

NATIONAL OCEAN SERVICE AND SEA TURTLES: HABITAT SUITABILITY

MODELING

Mr. Michael S. Coyne . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

SEA TURTLES AND THE NATIONAL MARINE FISHERIES SERVICE

Ms. Sheryan Epperly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
vii

U.S. GEOLOGICAL SURVEY/NATIONAL PARK SERVICE KEMP’S RIDLEY SEA

TURTLE RESEARCH AND MONITORING PROGRAMS IN TEXAS

Ms. Donna J. Shaver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

PROTECTING SEA TURTLES DURING DREDGING BY THE U.S. ARMY

CORPS OF ENGINEERS

Dr. David A. Nelson . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

THE NAVY AND MARINE MAMMAL CONCERNS THAT CAN APPLY TO

THE GULF OF MEXICO

Dr. Robert C. Gisiner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

SUMMARY

RECOMMENDATIONS AND PROPOSED ACTION ITEMS . . . . . . . . . . . . . . . . . . . . . 151

APPENDIX A: MARINE PROTECTED SPECIES WORKSHOP . . . . . . . . . . . . . . . . . . 155

APPENDIX B: EXPERT PANEL MEMBERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

APPENDIX C: ATTENDEES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

INDEX TO AUTHORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
ix

LIST OF FIGURES

Figure 1. Current status of the Florida manatee. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 2. Maximum winter aerial survey counts at Crystal and Homosassa

Rivers 1984-99. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 3. Causes of Florida Manatee Mortality: 1974-1997. . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Figure 4. Sea turtle distributions in the Gulf of Mexico. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Figure 5. Major sea turtle nesting sites (>100 nests/year). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Figure 6. The seismic industry will continue to increase the amount of in-sea

equipment for the acquisition of 3D seismic surveys. . . . . . . . . . . . . . . . . . . . . . . . . 55

Figure 7. A streamer cable rolled up on a drum. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Figure 8. An illustration of how a seismic survey is shot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Figure 9. A portion of an airgun array. Note the man kneeling for scale . . . . . . . . . . . . . . . . . 58

Figure 10. A schematic diagram of a specific airgun array, one that is 3,959 cubic inches

in total volume, has 3 subarrays (each line of ovals), uses 17 airguns

(each individual oval represents an airgun, and the nearest number represents

the volume of that gun in cubic inches), and measures 18 meters by 18.5

meters in size. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Figure 11. Data recorded by hydro phones for dual 3,397-cubic-inch arrays. Each of the

two arrays consists of 24 guns, eight in each of three subarrays. Each array is

20 meters wide by 15 meters long. These data are from a survey acquired in

May 1999. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Figure 12. The amplitude level for a typical seismic trace as a function of recording time

(the heavy line). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Figure 13. The cartoon shows schematically how marine 4- component seismic data are

acquired using a cable system, which is laid on the seafloor. Generally, two

vessels are used, one a source vessel and the other a cable deployment and

recording vessel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Figure 14. An example of imaging beneath gas using S-wave energy. . . . . . . . . . . . . . . . . . . . . 64
x

Figure 15. The basic concept of seismic time-lapse monitoring. . . . . . . . . . . . . . . . . . . . . . . . . 65

Figure 16. A real- world, North Sea field example where seismic attributes were used

to map the fluid distribution in a reservoir under production. . . . . . . . . . . . . . . . . . . 66

Figure 17. A depiction of an array of vertical cables, and the trenching of a cable into

the seafloor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Figure 18. Flight IIA guided missile destroyer (DDG), Winston S. Churchill. . . . . . . . . . . . . . 72

Figure 19. Explosive shock trail components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Figure 20. Potential test areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Figure 21. Exclusionary map of the Mayport test area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Figure 22. Exclusionary map of the Norfolk test area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Figure 23. Exclusionary map of the Pascagoula test area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Figure 24. Generalized dolphin hearing threshold, with the spectra of their

echolocation pulses and whistles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Figure 25. Hypothesized sperm whale hearing threshold, with spectra of their pulses

and seismic exploration pulses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Figure 26. The influence of scale on rate of dolphin encounters relative to seismic

signals. The rate should vary according to the scale of investigation, with

decreased sighting rate at low and high scales, but increased rate at

intermediary scales. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Figure 27. Spectrogram (top) and waveform (bottom) illustrating sperm whale pulses

and two forms of seismic signals. The spectrogram displays frequency

(y-axis) as a function of time (x-axis) with increased darkness indicating

increased amplitude. The waveform displays amplitude over time. Eight

sperm whale pulses are indicated, with center frequency at approximately

2.5 kHz. The first seismic pulse is also centered at 2.5 kHz, with little

energy below 1 kHz. The second pulse is centered at 900 Hz. The final

pulse, centered at less than 100 Hz, is an echo. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Figure 28. Determining impacts on protected species. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

Figure 29. Four approaches to coupling species distribution and habitat. . . . . . . . . . . . . . . . . 110
xi

Figure 30. Hypothetical habitat suitability model for Kemp’s ridley sea turtles. Predicts

potential winter distribution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
xiii

LIST OF TABLES

Table 1. Marine Mammals and Sea Turtles of the Gulf of Mexico. . . . . . . . . . . . . . . . . . . . . . 2

Table 2. Possible effects of offshore oil and gas development on marine mammals

(compiled by Robert J. Hofman). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Table 3. Questions for workshop advisory panel. ...................................5

Table 4. Minor/Historical Nesting Sites of Sea Turtles in the Gulf of Mexico

(<100 nests/ year). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Table 5. Summary of Incidental Take Statement for Sea Turtles. . . . . . . . . . . . . . . . . . . . . . . 69

Table 6. Calculated Critical TTS Distances (Nautical Miles). . . . . . . . . . . . . . . . . . . . . . . . . . 75
xv

ACKNOWLEDGMENTS

The Minerals Management Service thanks all participants of the Marine Protected Species

Workshop. Recognition must be given to the speakers whose individual presentations stimulated

discussions and exchange of information. Authors are listed by name with their articles.

We are grateful to the following individuals who served as expert panel members:

Robert Bonde, U.S. Geological Survey

Michael Coyne, NOAA, National Ocean Service

Roger Gentry, NOAA, National Marine Fisheries Service

Robert Gisiner, Office of Naval Research

Robert Hofman, Marine Mammal Commission

Thomas Jefferson, Ocean Park Conservation Foundation

Barbara Schroeder, NOAA, National Marine Fisheries Service

Peter Tyack, Woods Hole Oceanographic Institute

William Lang and Dagmar Fertl were the technical experts from MMS managing the issues of the

meeting, and Debra Vigil was the Contracting Officer’s Technical Representative managing the

contract for the meeting.

Appreciation is extended to the University of New Orleans, Office of Conference Services, the

contractor who handled the logistics. Their professional services were a contributing factor to the

success of this workshop.

The staff of the New Orleans Airport Hilton were responsive and professional in managing our

continually changing requests.
1

BACKGROUND

INTRODUCTION

Dr. William Lang

Ms. Dagmar Fertl

Minerals Management Service

The Minerals Management Service (MMS) is a bureau within the U.S. Department of the Interior.

It is responsible for ensuring that exploration and production of oil and gas reserves in Federal

offshore waters, the Outer Continental Shelf (OCS), are conducted in a manner that balances orderly

energy resource development with protection of the human, marine and coastal environments as

mandated under the Outer Continental Shelf Lands Act (OCSLA). To help meet these OCSLA

requirements and also comply with the National Environmental Policy Act (NEPA), the MMS

conducts various environmental analyses. Part of this process includes sponsoring new research

programs or studies to obtain needed data. A national OCS Environmental Studies Program was

initiated in 1973 to provide environmental information and analyses of marine and coastal

ecosystems within OCS planning areas (MMS 1990a).

The MMS often holds topic-specific workshops to review existing information and determine future

study needs. This workshop represents the third protected species meeting for the Gulf of Mexico

(GOM) (MMS 1983; 1990b). For this workshop, “Protected species” refers to those marine animals

afforded protection under the Endangered Species Act (ESA) and Marine Mammal Protection Act

(MMPA). The MMPA protects all marine mammals occurring in the GOM (twenty-eight cetacean

species and the West Indian manatee). The ESA lists six large whale species and the manatee as

endangered and five sea turtle species as threatened or endangered. The animals of concern are

GOM marine mammal and sea turtle species listed in Table 1.

Since the MMS does not maintain research facilities, nearly all MMS studies represent contracts to

external research groups or cooperative funding with state or federal agencies and industry. Though

the MMS strives to support studies that provide quality data useful to the broader community,

studies are not conducted for basic research purposes but to support programmatic needs. 

Although the MMS “Studies Program” was created in 1973 (then under the Bureau of Land

Management) to address information needs for the OCSLA and NEPA, in 1975, protected species

studies were initiated to support MMPA and ESA information needs and have remained an

important component of the studies program (MMS 1990a). Historically, protected species studies

funded by MMS began with surveys of the distribution and abundance of animals that may be at risk

in OCS planning areas as well as literature analyses, modeling and limited experimentation on

effects of oil spills and acoustic disturbance on marine mammals (Geraci and St. Aubin 1990;

Richardson et al. 1995). Early survey studies have evolved into multi-discipline analyses correlating

physical and biological parameters to marine mammals distributions, such as SCOPEX in the

Atlantic (Kenney & Wishner 1995) and Gulfcet II in the GOM (Davis et al. 2000). 
2

Table 1. Marine Mammals and Sea Turtles of the Gulf of Mexico.

Marine Mammals

Order Cetacea

Suborder Mysticeti (baleen whales)

Family Balaenidae 

Eubalaena glacialis, northern right whale *

Family Balaenopteridae

Balaenoptera musculus, blue whale *

Balaenoptera physalus, fin whale *

Balaenoptera borealis, sei whale *

Balaenoptera edeni, Bryde's whale

Balaenoptera acutorostrata, minke whale

Megaptera novaeangliae, humpback whale *

Suborder Odontoceti (toothed whales)

Family Physeteridae 

Physeter macrocephalus, sperm whale *

Family Kogiidae

Kogia breviceps, pygmy sperm whale

Kogia simus, dwarf sperm whale

Family Ziphiidae

Mesoplodon bidens, Sowerby's beaked whale

Mesoplodon densirostris, Blainville's beaked whale

Mesoplodon europaeus, Gervais' beaked whale

Ziphius cavirostris, Cuvier's beaked whale

Order Cetacea (continued)

Family Delphinidae

Orcinus orca, killer whale

Pseudorca crassidens, false killer whale

Feresa attenuata, pygmy killer whale

Globicephala macrorhynchus, short-finned pilot

whale

Grampus griseus, Risso's dolphin

Peponocephala electra, melon-headed whale

Tursiops truncatus, Atlantic bottlenose dolphin

Steno bredanensis, rough-toothed dolphin

Stenella coeruleoalba, striped dolphin

Stenella attenuata, pantropical spotted dolphin

Stenella clymene, Clymene dolphin

Stenella frontalis, Atlantic spotted dolphin

Stenella longirostris, spinner dolphin

Lagenodelphis hosei, Fraser's dolphin

Order Carnivora

Suborder Pinnipedia (seals, sea lions)

Family Otariidae

Zalophus californianus, California sea lion I

Family Phocidae

Monachus tropicalis, Caribbean monk seal Ex

Order Sirenia

Family Trichechidae

Trichechus manatus West Indian manatee *

Sea Turtles

Caretta caretta, loggerhead *

Lepidochelys kempi, Kemp’s ridley *

Dermochelys coriacea, leatherback *

Chelonia mydas, green *

Eretmochelys imbricata, hawksbill *

I = introduced; Ex = extinct; * = endangered
3

In addition to environmental studies and the workshop forum to evaluate issues and obtain new

information, MMS also funds research through the Technology, Assessment and Research Program

(TAR). TAR works with engineering and technology issues, often in close cooperation with

industry. For many effects issues, engineering analyses and technology assessment are essential

components to fully understand environmental effects. For example, recent efforts to better evaluate

effects of explosive removal of offshore structures on sea turtles and cetaceans has involved

cooperative planning with TAR, the Environmental Studies Program, and industry through the

Offshore Operators Committee.

As we begin this workshop, the types of possible effects of offshore petroleum activities on

protected species have been identified with few, if any, changes in the list since the 1980s (Geraci

and St. Aubin 1985). Dr. Robert Hofman of the Marine Mammal Commission listed these effects

during the 1989 workshop (Table 2). While this list of topics remains valid for 1999, the amount of

information for each topic has increased and perhaps, of most interest for this meeting, the

perception of relative risks has evolved. For example, information on effects of oil exposure on

marine mammals and means to clean and rehabilitate captured animals has substantially increased,

in no small part, due to extensive studies and experience resulting from the 1989 Exxon Valdez spill

(Loughlin 1994). Not that the concern or potential for impact has subsided, but the demand for

additional oil effects studies is considerably less in 1999 relative to the 1983 or 1989 workshops.

Conversely, although MMS has studied acoustic disturbance issues for Alaska protected species

from the onset of the studies program, the perception that potentially significant acoustic effects

from a variety of human activities exist in the world oceans is a recent trend (Jasny 1999). Acoustic

effects from offshore petroleum exploration was a recognized issue in the North Atlantic lease sale

NEPA documents in the 1980s, but remained a relatively secondary concern. In contrast, seismic

exploration is highlighted as a major concern during recent environmental assessments for proposed

petroleum exploration on the Canadian Georges Bank (NRC/NSPD 1999).

Participants at the 1989 workshop reviewed the existing state of knowledge for GOM protected

species and possible sources of impacts on them. The workshop was divided into invited

presentations, discussion groups, summation session, and culminated in the development of study

priorities. Marine mammal and sea turtle sessions were held separately. Recommendations from the

workshop directly contributed to MMS planning and funding of the GulfCet I study and

collaboration with the Biological Resources Division of the U.S. Geological Survey for award of

GulfCet II. A synopsis of Kemp’s ridley biological data from Dr. Rene Marquez (Marquez 1994)

was also supported by MMS and funding for marine mammal observers aboard NMFS research

vessels is an ongoing cooperative agreement.

This workshop was conducted differently from our two previous meetings. Since the 1989 workshop

effectively defined basic issues and research needs, the emphasis at this meeting was to review

accomplishments since 1989, what new factors should be considered, and what should MMS do

next? The number of presentations was increased relative to past workshops and they address the

range of topics integral to MMS programmatic planning. In addition to “biology” of protected

species, offshore industry activities, new technology and exploration trends were presented as well

as recent developments concerning the MMPA and ESA.
4

Table 2. Possible effects of offshore oil and gas development on marine mammals (compiled by

Robert J. Hofman).

I. Disturbance/noise from ship and aircraft operations, seismic profiling, platform construction,

drilling, etc., may

a. interfere with or disrupt vocal communications, feeding, breeding or other vital functions;

b. cause animals to avoid or abandon important feeding areas, breeding areas, resting areas, or

migratory routes;

c. cause animals to use marginal habitat or to concentrate in undisturbed areas, which in turn

may result in crowding, overexploited food resources, increased mortality, and decreased

reproduction;

d. stress animals and make them more vulnerable to parasites, disease, and/or predation;

e. attract animals, making them more vulnerable to oil spills, hunting, harassment; and

f. alter the distribution, density, movements, or behavior of important prey species.

II. Dumping, dredging, drilling, and platform, pipeline, support facility, and storage facility

construction may

a. damage or destroy haul-out sites, feeding areas, or other areas of similar importance; and

b. adversely affect the distribution, abundance, behavior, or productivity of important prey

species.

III. Oil from well blowouts, pipeline breaks, tanker accidents, and chronic discharges associated with

routine operations may

a. kill or debilitate marine mammals by matting and reducing the insulating quality of fur; cause

acute or chronic poisoning due to inhalation or ingestion of toxic hydrocarbon components

or ingestion of contaminated food; cause irritation of skin, eyes, or mucous membrane, or

fouling of baleen;

b. kill, debilitate, or otherwise reduce the abundance or productivity of important prey species

and/or species lower in the marine food web, resulting in acute or chronic nutritional

deficiencies, including starvation;

c. stress animals, making them more vulnerable to disease, parasitism, and/or predation;

d. interfere with the formation of mother-pup bonds and cause mothers (particularly colonial

breeding pinnipeds) to abandon pups;

e. cause animals to abandon or avoid contaminated breeding areas, feeding areas, etc., and/or to

concentrate in unaffected areas; and

f. attract animals to debilitated prey, making them more vulnerable to contact with oil and the

ingestion of contaminated prey.

IV. Contaminants in drilling muds, waste discharge, etc. may

a. kill or debilitate animals that are exposed to the contaminants; and

b. contaminate, accumulate in, and kill or debilitate important prey species or species lower in

the marine food web.

V. Increased ship traffic may increase the probability of collisions between ships and marine

mammals.
5

Rather than breakout groups, nine protected species experts were invited to participate in a

workshop advisory panel. As detailed in the summary chapter, the panel received four questions

(Table 3) from the MMS as topics to stimulate discussions. Following a panel discussion, there was

an open floor discussion to allow for additional questions, feedback and perspectives from all

workshop participants. After the workshop, MMS staff and other federal representative met with the

expert panel for a post-workshop evaluation and an additional opportunity to discuss study planning.

Table 3. Questions for workshop advisory panel.

Suggested Questions for Discussion by Expert Panel

The purpose of the workshop is to identify the significant uncertainties and propose research and

monitoring programs needed to resolve them. 

In view of the sponsor of the workshop, the first priority is to address information needs most

pertinent to MMS-regulated activities. The discussion will then be open for the panel to discuss

other important items of concern.

1. Will a move into deeper water for exploration and production bring special considerations

and concerns that have not yet been addressed by prior studies?

2. What special concerns will MMS need to address in the Eastern Planning Area and other

shallow water areas in the Gulf?

3. The following are environmental assessment specific questions that the MMS has

received. Can these concerns be addressed and what is the approach?

A. MMS lease sale environmental impact statements were noted to have little

information on the distribution patterns or abundance of the individual marine

mammal species and populations that inhabit the northern Gulf or how they would

likely be affected. 

B. Difficulties exist relative to indicating specific areas where seismic surveys, drilling,

helicopter and vessel support activities, etc., might overlap with important feeding,

breeding, calving, nursing, or migratory areas.

C. What type of research or monitoring programs are needed to address points A and B?

4. What should MMS’s role in understanding, and conservation, of protected species be in

relation to other government/funding agencies and research groups?
6

Although there are multiple purposes for sponsoring this type of workshop, the key factor for MMS

is to plan protected species aspects of a deep-water studies program. As industry moves into deeper,

less studied areas along the continental slope, additional information is needed on the protected

species occurring there. A number of human activities, the oil and gas industry being one source,

have the potential to affect GOM protected species. From the standpoint of planning studies, the

MMS would like to better define the most significant environmental issues for Gulf protected

species, including putting petroleum industry activities in perspective with other issues. The years

of effort and millions of dollars in funding for Gulfcet II and I have resulted in significant new

findings which will be highlighted at this meeting. While GulfCet studies have proven to be a

milestone effort in the history of GOM (as well as global) marine mammal research, how much has

been accomplished in terms of addressing the identified issues listed in 1989? We think the answer

to that question will emphasize the need for cooperative efforts and sharing resources and that this

workshop will provide MMS and others with valuable information for planning future research.

REFERENCES

Davis, R.W., W.E. Evans, and B. Wursig, eds. 2000. Cetaceans, Sea Turtles and Seabirds in the

Northern Gulf of Mexico: Distribution, Abundance and Habitat Associations. Volume I:

Executive Summary. Prepared by Texas A&M University at Galveston and the National Marine

Fisheries Service. U.S. Department of the Interior, Geological Survey, Biological Resources

Division, USGS/BRD/CR-1999-0006 and Minerals Management Service, Gulf of Mexico OCS

Region, New Orleans, LA. OCS Study MMS 2000-002, 27 pp.

Geraci, J.R. and D.J. St. Aubin. 1985. Effects of Offshore Oil and Gas Development on Marine

Mammals and Turtles. In D.F. Boesch and N. N. Rabelais, eds. Long-Term Environmental

Effects of Offshore Oil and Gas Development. Elsevier Applied Sciences, NY, pp. 587-612.

Geraci, J.R. and D. J. St. Aubin. eds. 1990. Sea Mammals and Oil: Confronting the Risks. Academic

Press, Inc., San Diego, California.

Jansy, M. 1999. Sounding the Depths: Supertankers, Sonar, and the Rise of Undersea Noise. Natural

Resources Defense Council, March 1999.

Kenney, R. D. and K. F. Wishner, eds. 1995. The South Channel Ocean Productivity Experiment:

SCOPEX. Continental Shelf Research, Vol. 15:373-611.

Loughlin, T. R., ed. 1994. Marine Mammals and the Exxon Valdez. Academic Press, Inc., San

Diego, California.

MMS. 1983. Proceedings of a Workshop on Cetaceans and Sea Turtles in the Gulf of Mexico. April

1982. Minerals Mgmt. Service/Fish and Wildlife Service FWS/OBS-83/03.

MMS. 1990a. The Offshore Environmental Studies Program (1973-1989). A Summary of Minerals

Mgmt. Service Research Conducted on the U.S. Outer Continental Shelf. Minerals Mgmt.

Service OCS Report MMS 90-0095.
7

Marquez-M., R. 1994. Synopsis of biological data on the Kemp’s ridley turtle, Lepidochelys kempi,

(Garman, 1880). NOAA Technical Memorandum NMFS-SEFSC-343, 91 pp., or OCS Study

MMS 94-0023.

NRC/NSPD. 1999. Georges Bank Review Panel Report. June 1999. Natural Resources Canada/Nova

Scotia Petroleum Directorate.

Richardson, W.J., C.R. Greene, Jr., C.I. Malme, and D.H. Thomson. 1995. Marine Mammals and

Noise. Academic Press, San Diego, California.

Tucker & Associates, Inc. 1990. Sea turtles and marine mammals of the Gulf of Mexico,

proceedings of a Workshop Held in New Orleans, August 1-3,1989. Minerals Mgmt. Service OCS

Study MMS 90-0009. U.S. Dept. of the Interior, Minerals Management Service, Gulf of Mexico

OCS Regional Office, New Orleans, LA. 211 pp.

Dr. William Lang is a senior oceanographer at the MMS Gulf of Mexico OCS Region Office. After

several years work with the Environmental Protection Agency on marine toxicology and water

quality issues, he joined the MMS Studies Program, working for the Atlantic OCS Region Office

in New York City. He worked on MMS’s initial cetacean and sea turtle surveys conducted in the

northeast and then coordinated all MMS protected species studies from headquarters in Washington,

DC. After positions in environmental assessments and operations dealing with information

management and environmental policy/regulations, Dr. Lang has most recently focused on protected

species issues in the Gulf of Mexico. He received his B.S. from Lafayette College, his M.S. from

Rutgers University, and his Ph.D. from the University of South Carolina.

Ms. Dagmar Fertl is currently a senior environmental scientist with Geo-Marine, Inc. She worked

with the MMS-Gulf of Mexico Region for over five years. Ms. Fertl has over 12 years of research

experience work with cetaceans in the Gulf of Mexico. While at MMS, she specialized in

preparation of protected species information for NEPA documents and assisted in monitoring both

of the GulfCet studies. Projects for public outreach, including a teacher’s packet, cetacean poster,

and web pages for the MMS site, are some of her other accomplishments while with the MMS.

These efforts were recognized in the form of a Department of Interior national award in 1999. Ms.

Fertl received her bachelor’s degree from Trinity University and her master’s degree from Texas

A&M University for a study of dolphin interactions with the shrimp fishery in Texas. She has also

published over 20 peer-reviewed articles on marine mammals.
8

ELEMENTS OF STUDIES OF PROTECTED SPECIES IN THE GULF OF MEXICO:

HISTORY, PHILOSOPHY, AND RESEARCH

Dr. William E. Evans

Texas A&M University (Retired)

SURVEYS OF PROTECTED SPECIES IN THE NORTHERN

GULF OF MEXICO PRIOR TO 1991

Marine ecosystems contain one-third to one-half of all species. This is not altogether surprising

considering that the marine realm forms 71% of the area and 95% of the volume of the biosphere

(Angel 1993). Some marine habitats, particularly coastal habitats in and around harbors, are more

heavily impacted than their terrestrial counterparts (Carlton and Geller 1995). Although marine

species may compose as many as half of all species, few are included in estimates of species

extinction rates. Failure to secure information about loss of species and decreases in populations in

a timely manner places entire ecosystems at risk (Naeen et al. 1994), as well as human economies

dependent on these resources (Hamre 1994). 

We were aware from Townsend’s analysis of the 19th and early 20th century sperm whaling records

that groups of sperm whales aggregated on the continental slope off of the mouth of the Mississippi

(Townsend 1935). Other than that, our knowledge of cetaceans in the Gulf of Mexico was limited

to data from the live capture fishery for bottlenose dolphins for the increasing number of oceanaria

being developed after World War II. With the exception of data on manatees and museum records

of strandings, our knowledge of protected species in the Gulf of Mexico prior to 1970 has been

sketchy at best.

Until recently, relatively little was known about cetaceans, sea turtles and sea birds inhabiting deeper

waters of the Gulf of Mexico. From July 1989 through June 1990, NMFS conducted aerial surveys

of cetaceans and turtles along the continental slope of the north-central Gulf of Mexico in water

ranging from 180-1,800 m deep (Mullin et al. 1991, Mullin 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. The most commonly sighted groups, were: (1) Risso's dolphins, sperm whales,

bottlenose dolphins, Atlantic spotted dolphins, dwarf/pygmy sperm whales, striped/spinner/clymene

dolphins, pantropical spotted dolphins, beaked whales, and short-finned pilot whales. 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 short-finned 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.
9

THE GULFCET I PROGRAM: HOW MANY AND WHERE ARE THEY?

The most intensive and extensive survey of cetaceans in the offshore waters (100 to 2,000 m deep)

of the north-central and western Gulf of Mexico was conducted jointly by Texas A&M University

and the NMFS, Southeast Fisheries Science Center beginning in (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. 

RESULTS

A total of 21,350 km of transect was visually surveyed from ships during GulfCet I. The cumulative

survey effort for 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 as in Texas and probably Louisiana, 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-effort sightings 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

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 in the GulfCet I study area was 19,198 animals. This was not inconsistent

with estimates from studies prior to 1992.

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 commonly recorded 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 Jefferson and

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. Within
10

the 154,621 km2 study area, the total estimated population of sperm whales is 316 individuals (265-

377). On the 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 the 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/1000 km2. The total

estimated dolphin population within the study area was 36,760 animals (30,835-43,821). 

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 varied seasonally from

11,756-12,942 km. In total, 351 cetacean groups were sighted on-effort. The number of sightings

during 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 and sperm whales. 

Overall, there were an estimated 16,986 cetaceans in the GulfCet I aerial survey study area. There

were an estimated 12,690 cetaceans the first year and 20,669 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) and spring (19,215), a little less in summer (14,959) but two to

three times lower in the fall (6,051).

Pantropical spotted dolphins were the most abundant species in the aerial survey study area (5,251)

followed by melon-headed whales (2,980) bottlenose dolphins (2,890) and Risso's dolphins (1,214).

The sperm whale population was estimated to be 87 and pygmy/dwarf sperm whales, 176 All the

other delphinid 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 but showed the strongest

correlation of species distribution with ocean depth. This study, however, 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.
11

GULFCET II: OCEANOGRAPHIC AND BIOLOGICAL CORRELATES TO DISTRIBUTION

As early as the mid-19th century it was suspected that the location of sperm whale populations were

affected by oceanographic conditions such as ocean currents (Townsend 1935).

The recent decade’s developments in satellite technology and rising interest in and deployment of

ocean buoy-platforms from which to monitor both surface and subsurface ocean processes are

providing a growing basis for a better understanding of climate driven ocean variability and its

influence on the variability of biological systems.

The objectives of the GulfCet II program were to: 1) estimate the minimum abundances of cetaceans

and sea turtles and 2) characterize the distribution and habitat-associations of cetaceans and seabirds

in the eastern Gulf and oceanic northern Gulf, with an emphasis on the continental slope (waters

100-2,000 m deep) (Figures 1.4 and 1.5). This study was a continuation of surveys in the oceanic

north-central and western Gulf that began during the GulfCet I program and extended into the

northeastern Gulf.

To accomplish these objectives, we used an integrated approach that included visual (aerial and

shipboard) and acoustic (shipboard) surveys of the distribution of cetaceans, sea turtles and seabirds

and simultaneous hydrographic measurements. We also used near real-time sea surface altimetry

from the TOPEX/POSEIDON and ERS satellites to determine the location of hydrographic features

(e.g., cyclones, anticyclones and confluence zones) during shipboard surveys. The sea surface

altimetry maps enabled us to adjust the ship’s course so that we could survey and sample

hydrographic features that could influence the distribution of cetaceans and seabirds. Archival

satellite sea surface altimetry data also allowed us to retrospectively determine the location of

hydrographic features for analysis with GulfCet I cetacean sightings collected from 1992-94. In

addition to characterizing hydrographic features during GulfCet II, we measured zooplankton and

micronekton biomass derived from both net and acoustic sampling to indicate the amount of

potential food available for higher trophic level foraging by cetaceans and seabirds. We

hypothesized that hydrographic regimes in the study area had different levels of potential prey that

influence cetacean and seabird distribution. We further hypothesized that these food stocks would

be locally concentrated in nutrient-rich areas offshore from the Mississippi River, within cyclonic

eddies, and along the high-shear edges of cyclonic eddies.

RESULTS

The physical forcing functions for ocean circulation in the north-central and eastern Gulf of Mexico

are river discharge, wind stress, and the Loop Current (LC). The major river system influencing this

region is the Mississippi-Atchafalaya River, with most of the outflow transported west along the

coast (Cochrane and Kelly 1986). Flow on the continental shelf is largely wind-driven, with

buoyancy forcing effects from low-density river water. Beyond the shelf-break, the LC largely

determines mesoscale circulation. Once or twice annually, the LC sheds anticyclonic, warm-core

eddies that migrate westward and spawn cyclonic, cold-core eddies. The upward flux of nutrients

in cold-core eddies stimulates biological productivity in the near-surface mixed layer (Biggs et al.

1988, Biggs 1992). 
12

In contrast, the LC and warm-core eddies are depleted of nutrients in the photic zone and have lower

productivity. In addition, frontal zones at the periphery of eddies can entrain low salinity, highchlorophyll shelf water and transport it off the shelf (Biggs and Muller-Karger 1994). Frontal zones

may also be created during periods of northern extension of the LC. 

Recent studies have used acoustic techniques to assess zooplankton and micronekton biomass as a

direct or indirect index of food resources for cetaceans (Croll et al. 1998; Macaulay et al. 1995;

Beardsley et al. 1996; Fiedler et al. 1998). Although there was a pronounced diel fluctuation in the

vertical migration of sound-scattering organisms during this study, integrated PMB was always

greater in cold-core eddies than in warm-core eddies. These former areas have a shallower MLD and

lower dynamic SSH or SSH anomaly due to doming of cold, deep water. Our results show that coldcore eddies are areas of locally concentrated zooplankton and micronekton, including cephalopod

paralarvae and myctophids, due to increased nutrient-rich water and primary production in the mixed

layer (Biggs et al. 1988). The presence of cetacean species or groups is correlated with the locations

of these mesoscale features. Since cold-core eddies in the northern Gulf are dynamic and usually

associated with westward moving warm-core eddies, cetacean distribution is dynamic. However,

with near real-time satellite remote sensing of SSH anomaly, these features can be tracked and used

to predict where cetaceans may be concentrated. 

In addition to cold-core eddies, ocean depth influences cetacean distribution in the northern Gulf.

In earlier studies (Davis and Fargion 1996; Baumgartner 1997; Davis et al. 1998; Mullin et al.

1998), the distribution of cetaceans in the north-central and western Gulf of Mexico in waters deeper

than 100 m (i.e., the GulfCet I study area) was differentiated most clearly with ocean depth. Atlantic

spotted dolphins were consistently found in the shallowest water on the continental shelf and along

the shelf break. In addition, the seafloor slope was less for Atlantic spotted dolphins than for any

other species. Bottlenose dolphins were found most commonly along the upper slope in water

significantly deeper than that for Atlantic spotted dolphins. All the other species and species

categories were found over deeper ocean depths; these were Risso's dolphins, short-finned pilot

whales, pygmy/dwarf sperm whales, rough-toothed dolphins, spinner dolphins, sperm whales,

striped dolphins, Mesoplodon spp., pantropical spotted dolphins, Clymene dolphins and unidentified

beaked whales (Ziphiidae). Risso's dolphins and short-finned pilot whales occurred along the upper

slope and, as a subgroup, were significantly different from striped dolphins, Mesoplodon spp.,

pantropical spotted dolphins, Clymene dolphins, and unidentified beaked whales, which occurred

in the deepest water. Pygmy/dwarf sperm whales, rough-toothed dolphins, spinner dolphins, and

sperm whales occurred at intermediate depths between these two subgroups and overlapped them.

Our results for the northern oceanic Gulf are consistent with these earlier results.

In the current study, cetaceans were concentrated along the continental slope and were less likely

to occur in water greater than 2,000 m deep. The explanation for this is uncertain although collision

of mesoscale eddies with the continental margin may further enhance primary and secondary

productivity, especially along the upper slope (Griffin 1999). Skipjack, blackfin tuna, swordfish, and

blue marlin have been reported by fisherman to be locally abundant in these areas (Roffer’s Ocean

Fishing Forecasting Service). The presence of large, apex-predators such as tuna, billfish and

cetaceans indicates reliable food resources along the continental slope.
13

In the north-central Gulf, an additional factor may be the narrow continental shelf near the mouth

of the Mississippi River. Low salinity, nutrient-rich water is entrained by eddy circulation and

transported over the continental slope. This creates a deep-water environment with enhanced

primary and secondary productivity, which may explain the presence of a resident population of

endangered sperm whales within 25 km of the Mississippi River delta. Although the diet of sperm

whales in the northern Gulf is unknown, squid are typically the most important component followed

by fish (Berzin 1971). Sperm whales in the north-central Gulf occur along the mid-to-lower slope

(Collum and Fritts 1985; Davis et al. 1998) in areas with lower dynamic SSH, higher PMB and

shallower MLD. The occurrence of sperm whales in similar ocean depths (200 to 1,500 m;

Whitehead et al. 1992) and in areas of increased productivity along frontal systems (Waring et al.

1993; Griffin 1999) has been observed off the continental shelf of Nova Scotia and the northeastern

United States. In the South Pacific, sperm whales occur in areas with high secondary productivity

and steep underwater topography (Jaquet and Whitehead 1996; Jaquet, Whitehead and Lewis 1996).

However, the results of a Chi-square test that combined GulfCet I and GulfCet II sightings for the

entire oceanic northern Gulf showed a random distribution with respect to oceanographic features.

This indicates that factors other than food distribution may influence the sperm whale distribution

(Jaquet and Whitehead 1996; Jaquet, Whitehead and Lewis 1996). As with sperm whales, similar

correlations with lower dynamic SSH, higher PMB and shallower MLD were obtained for the squideaters and oceanic stenellids, although squid-eaters occurred along the upper slope and stenellids

along the lower slope and in water greater than 2,000 m deep (Jennings 1982).

Unlike the other cetacean species or groups, the distribution of bottlenose dolphins and Atlantic

spotted dolphins was not correlated with the cold-core eddies that occur in deeper waters beyond

the shelf break. The preference of these two species for the shallow waters of the continental shelf

and upper slope generally precludes them from feeding around cold-core eddies. The same appears

to be true of Bryde’s whale, which have been sighted in the northeastern Gulf in water 100 m deep

(Davis et al. 1998; see also Chapter 4) and along the shelf break (Mullin et al. 1998). We have little

information on the environmental variables that influence the distribution of these species or their

prey because hydrographic surveys have concentrated on deeper waters beyond the continental shelf.

CONCLUSIONS

Cetaceans in the northeastern and oceanic northern Gulf of Mexico are concentrated along the

continental slope in or near cold-core eddies. These eddies are mesoscale features with locally

concentrated zooplankton and micronekton due to increased nutrient-rich water and primary

production in the mixed layer. The exceptions were bottlenose dolphins, Atlantic spotted dolphins

and possibly Bryde’s whale that typically occur on the continental shelf or along the shelf break

outside of major influences of eddies. Low salinity, nutrient-rich water from the Mississippi River

also contributes to enhanced primary and secondary productivity in the north-central Gulf and may

explain the presence of a resident population of endangered sperm whales south of the delta. Since

cold-core eddies in the northern Gulf are dynamic, cetacean distribution may change in response to

the movement of prey associated with these hydrographic features.

Sounds associated with offshore oil exploration in the Gulf of Mexico are becoming increasingly

common. The peak intensity of seismic exploration pulses recorded during GulfCet II was found to
14

be typically below 250 Hz, with an average peak intensity at 82 Hz. The average intensity of pulses

was found to be 8.4 dB above ambient, more than double ambient levels. However, there was no

significant difference in the sighting frequency between the different acoustic levels examined for

GulfCet I and II, contrary to previous findings (Mate et al. 1994). In addition, the observed

distribution of cetaceans did not differ significantly with seismic sound intensity for different

hydrographic regions. However, this study did not examine smaller-scale behavioral impacts. While

the GulfCet I and II Programs offered an opportunity to examine the potential effects of human

acoustic perturbation on the large-scale distribution of local cetacean populations, they lacked the

ability to control for both the acoustic level and the hydrographic region. To better understand the

potential impact of man-made noise on local cetacean populations, a systematic study is needed that

can control acoustic variation in different hydrographic features. Ideally, such a study would

examine small-scale behavioral changes in addition to distribution. 

Loggerhead, Kemp’s ridley, and leatherback sea turtles inhabited shelf waters but loggerheads were

by far the most abundant. (Kemp’s ridley sea turtles are very difficult to see due to their small size,

and these results probably do not accurately represent their abundance relative to loggerheads.)

Loggerhead sea turtles were widely distributed in shelf water with similar abundance during both

summer and winter.

The three cruises provided more information on seasonal distribution and abundance of seabirds in

the Gulf of Mexico. The relationship between hydrographic environment and species diversity was

examined. We found the highest species diversity in the cyclone and lowest on the continental shelf.

Several species exhibited affinities to specific hydrographic environments. Pomarine jaegers and

black terns preferred the MOM area. Audubon’s shearwaters were more likely to be present in the

cyclone, and band-rumped storm-petrels in “other margin” areas. Species’ presence was analyzed

with models incorporating bottom depth, sea-surface properties, and plankton standing stocks using

generalized additive models. Results suggest that the presence of laughing gull, Audubon’s

shearwater, band-rumped storm-petrel and bridled tern presence was best predicted by indicators

of plankton-standing stock, using sea surface chlorophyll concentrations and PMB as predictor

variables. For laughing gull, black tern and sooty tern, sea surface temperature and salinity best

predicted presence. Models incorporating sea surface height and bathymetry predicted pomarine

jaeger and Audubon’s shearwater presence.

DISCUSSION: WHAT IS THE NEXT STEP?

The answers to this question vary with every vested interest group, but I believe that the first step

is for someone to take full responsibility for the Gulf of Mexico as publicly owned, not necessarily

renewable common properties. The major tasks ahead are to develop the necessary multidisciplinary

capabilities of the scientific community to use these new tools to conduct appropriately scaled

research on causal processes and sequences of physical and ecological responses. Then the most

effective, cost-efficient mechanism for monitoring and managing the entire array of resources,

mineral and biological should be designed with the future in mind. This then needs to be

implemented as efficiently and effectively as possible in the face of the inertia of the present system.

This will not be an easy task, but it is now under way. Don’t we have the necessary system already?

Clearly the answer is no.
15

Progress in our understanding of protected species in the Gulf of Mexico from 1970s to the present

has grown. We have gone from just knowledge of presence of certain protected species, to a good

understanding of numbers, distribution and now an understanding of habitat, not only for cetacea,

and sea turtles but sea birds. What is the next step? Basically our purpose here is to concentrate on

determining the potential impact of oil and gas activities on these protected species. Are we at the

point where we know enough that we can now enter into a monitoring phase? How much monitoring

is enough? Can satellite oceanographic data and aerial surveys define the dynamic features of the

Gulf well enough to detect significant changes in species numbers and distribution?

A workshop on the Protected Species of the Gulf of Mexico was convened under contract with the

United States Environmental Protection Agency, Gulf of Mexico Program. This workshop was held

on 24 and 25 April 1996. Some of the recommendations from that workshop are worthy of

consideration here with modification:

• Enhance existing research and monitoring programs that assist in the identification of critical

ecosystem components and in the preservation of the full range of distinct ecosystems. Areas

identified must have sufficient contiguity to insure adequate gene flow and population

numbers. These will include identifying, censusing, and complex mapping (both geographic

and ecological) targeted marine species and associated physical data, necessary to delineate

ecosystem types. Simple compilations of statistics on a handful of popular species will be

wholly inadequate. It will must include identifying habitats common to the wide range of

protected species that require special attention and preservation, as well as establishing

protocols to determine the most cost-effective solutions. 

• Develop both theory and data necessary to implement both large and small scale

computational models designed to make specific predictions of loss or changes in

biodiversity within the Gulf of Mexico. These models should commence with current data

from recent assessments and other ongoing monitoring activity. Models should then grow

with refinement to include all other species. 

• Improve quantitative methods of analyzing existing information on biodiversity to enhance

its predictive capabilities, particularly those evaluating spatial data and frequency

distributions in the presence of sparse sampling. 

• Increase interagency efforts to identify and disseminate in electronic form currently existing

data, "gray literature", and other information pertinent to the study of biodiversity,

particularly that relevant to the documentation of historical trends essential to the

determination of rates of species and population loss and gain both Gulf-wide and locally.

• Enhance research training opportunities for new scientists, students, and the general public

that are critical to increased programmatic and scientific capabilities in the future. This is

of special concern because human-induced stresses on Gulf ecosystems are greatly

increasing at a time when taxonomic expertise is rapidly declining. Should this trend

continue un-addressed, it will soon be impossible for scientifically sound studies to be
16

conducted or rational management policies to be implemented. Lack of such studies and

policies would place both public health and the economy at risk. 

• Improve facilities used to study biodiversity, particularly research collections that serve as

the principal sites for the creation and dissemination of new primary data of importance to

both applied and basic science, as well as to general economic development of biodiversity

resources.

• Improve ties between research collections and personnel within the academic community

that utilize such collections and federal and state management, preservation, and monitoring

activities of federal and state agencies so that the archival value of research collections can

be better utilized in ongoing management efforts to study and conserve biodiversity. 

• Improve research collections to facilitate state-of-the-art training sites for a wide range of

students and professionals, who must become far more knowledgeable of existing

biodiversity, if they are to collectively ensure a sustainable future. Such training should not

only include biologists, but should be designed to applicable to computer scientists,

construction engineers, architects, city and industrial planners, lawyers, law enforcement

personnel, real estate and housing developers, and others actively involved in land use and

management. 

• Insure that routinely funded ecological and oceanographic monitoring of all kinds. This

should include environmental assessments associated with environmental impact statements,

particularly those that involve environmentally sensitive areas. Most such impact statements

are notoriously poor in establishing the identity of potentially impacted species. 

• Develop quantitative research and sampling methods that will permit marine organisms to

be studied with the minimum of perturbation, while maximizing the accuracy of observation.

These should include on-line acquisition and monitoring of certain key data, including those

involving measurement of the extent and quality of existing habitat and population numbers

of carefully chosen species. In the case of the MMS Eastern Planning Area, sperm whales

are a good candidate.

• Information is needed on the movements, diving behavior and site fidelity of endangered

sperm whales along the continental slope southeast of the Mississippi River delta. Satellite

telemeters should be attached to sperm whales to examine seasonal movements and preferred

foraging depths. Skin biopsy samples should be collected to determine how closely related

Gulf sperm whales are to those from the adjacent Atlantic Ocean and Caribbean Sea. A

photo-identification study in this region should be conducted to assess the site fidelity of

individual whales.

• Fund studies of the economic impacts of changes and loss of biodiversity in the Gulf of

Mexico.
17

REFERENCES

Baumgartner, M.F. 1997. Distribution of Risso’s dolphin (Grampus griseus) with respect to the

physiography of the northern Gulf of Mexico. Mar Mamm. Sci. 13:614-638.

Beardsley, R.C., A.W. Epstein, C. Chen, K.F. Wishner, M.C. Macauly, R.D. Kenny. 1996. Spatial

variability in zooplankton abundance near feeding right whales in the Great South Channel.

Deep-Sea Res.II 43: 1601-1625.

Berzin, A.A. 1971. Kashalot. Izdatel’stvo Pishchevaya Promyshlennost, Moskuva (The Sperm

Whale). Israel Program for Scientific Translations, Jerusalem. (English Translation, 394pp).

Biggs, D.C. 1992. Nutrients, plankton and productivity in a warm-core ring in the western Gulf of

Mexico. J. Geophys. Res. 97: 2143-2154.

Biggs, D.C. and F.E. Muller-Karger. 1994. Ship and Satellite observations of chlorophyll stocks in

interacting cyclone-anticyclone eddy pairs in the western Gulf of Mexico. J. Geophys. Res.

7371-7384.

Biggs, D.C., A.C. Vastano, R.A. Ossinger, Gil-Zurita and A. Perez-Franco. 1988. Multidisciplinary

study of warm and cold-core rings in the jGulf of Mexico. Mem. soc. Cienc. Nat. la Salle 48:11-

31.

Cochrane, J.D. and F.J. Kelly. 1986. Low frequency circulation on the Texas-Louisiana shelf. J.

Geophys. Res. 91: 10645-10659.

Croll, D.A., B.R. Tershy, R.P. Hewitt, D.A. Demer, P.C. Fiedler, S.E. Smith, W. Armstrong, J.M.

popp, T. Kiekhefer, V.R. Lopez, J. Urban, and d. Gendron. 1998. An integfrated approach to the

foraging ecology of marine birds and mammals. Deep-Sea Res. II 45: 1353-1371.

Davis, R.W. and G.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 Management Service, Gulf of Mexico

OCS Region, New Orleans, LA. 357 pp.

Fiedler, P.C., J. Barlow, and T. Gerrodette. 1998. Dolphin prey abundance determined from acoustic

backscatter data in eastern Pacific surveys. Fish. Bull. 96: 237-247.

Fritts, T.H., Irvine, AB, Jennings, R.D., Collum, L.A., Hoffman, 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.

Griffin, R.B. 1999. Sperm whale distributions and community ecology associated with a warm core

ring off Georges Bank. Mar. Mamm. Sci. 15:33-51.
18

Jaquet, N. and H. Whitehead. 1996. Scale-dependent correlation of sperm whale distribution with

environmental features and productivity in the South Pacific. Mar. Ecol. Prog. Ser. 135:1-9.

Jaquet, N., H. Whitehead, and M. Lewis. 1996. Coherence between 19th century sperm whale

distributions and satellite-derived pigments in the tropical Pacific. Mar. jEcol. Prog. Ser. 145:

1-10.

Jaquet, Nathalie, 1996. How spatial and temporal scales influence understanding of Sperm Whale

distribution: a review. Mammal Rev. Vol. 26, No. 1 51-65

Jefferson, T.A and Shiro, A.J. 1997. Distribution of cetaceans in the offshore Gulf of Mexico.

Mammal. Rev. 27:27-50.

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 (Lagenodelphis Hosei) in the Gulf of Mexico.

Texas J. Sci. 45:349-354.

Macaulay, M.C., K.F. Wishner, and k. Daly. 1995. Acoustic scattering from zooplankton and

micronekton in relation to a whale feeding site near Georges Bank and Cape Cod. Cont. Shelf

Res. 14: 509-537.

Mullin, K., Hoggard, W., Roden, C., Logoefener, R., Rogers, C., and Taggart, B. 1991. Cetaceans

on the upper continental slope in the north-central Gulf of Mexico. OCS Study/MMS 91-0027.

U.S. Dept. of the Interior, Minerals Management 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., and L.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. 70pp.
19

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.

Townsend, C.H., 1935. The Distribution of Certain Whales as Shown by Logbook Records of

American Whaleships. Zoologica, 19:1-2, 2-50.

Waring, G.T., C.P. Fairfield, C.M. Ruhsam, and M. Sano. 1993. Sperm whales associated with Gulf

Stream features off the north-eastern USA shelf. Fish. Oceanogr. 2: 101-105.

Waring, G.T., D.L. Palka, K.D. Millin, J.H.W. Hain, L.J. Hansen, and k.D. Bisack. 1997. U.S.

Atlantic and Gulf of Mexico Marine Mammal Stock Assessment-1996. NOAA Technical

Memorandum NMFS-NE-114, 250 pp.

Whitehead, H., S. Brennan, and D. Grover. 1992. Distribution and behavior of male sperm whales

on the jScotian Shelf, Canada. Can J. Zool. 70: 912-918.

Dr. William Eugene Evans is a Retired Professor of Marine Biology and Marine Science at Texas

A&M University. His career has also included the following positions: President of the Texas

Institute of Oceanography; Dean of the Texas Maritime College at Texas A&M; Superintendent of

the Texas State Maritime Program; Under Secretary of Commerce for Oceans and Atmosphere and

Administrator of NOAA; U.S. Commissioner to the International Whaling Commission; Assistant

Administrator of NOAA for Fisheries; Chairman of the Marine Mammal Commission; Senior

Lecturer at Scripps Institution of Oceanography (University of California, San Diego); and

President, Executive Director and Senior Scientist of Hubbs-Sea Work Research Institute. Dr.

Evans’ personal research has concentrated on the use of remote sensing technology in meso-scale

studies of oceanic marine living resource dynamics and acoustics. He received his B.S. from

Bowling Green State University, his M.S. from Ohio State University, and his Ph.D. from the

University of California at Los Angeles.
20

THE MARINE MAMMAL PROTECTION ACT

Dr. Robert Hofman (Retired)

Marine Mammal Commission

This paper summarizes the provisions of the Marine Mammal Protection Act (MMPA) of particular

relevance to oil and gas exploration and development in the northern Gulf of Mexico. Enacted in

October 1972, the MMPA established a general moratorium on the taking of marine mammals in

areas under U.S. jurisdiction. It defines the term “take” to mean “to harass, hunt, capture, or kill, or

attempt to harass, hunt, capture, or kill any marine mammal.” Amendments to the MMPA in 1994

define the term “harassment” to mean “any act of pursuit, torment, or annoyance which (i) has the

potential to injure a marine mammal or a marine mammal stock in the wild; or (ii) has the potential

to disturb a marine mammal or a marine mammal stock in the wild by causing disruption of

behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding,

or sheltering.”

The Act provides that the moratorium on taking can be waived if certain conditions are met—e.g.,

if available data are sufficient to reasonably conclude that the affected species or population is

within its optimum sustainable population (OSP) range and will not be “disadvantaged” by the

proposed taking. The Act also provides that permits may be issued to allow taking of marine

mammals for purposes of scientific research and public display when certain conditions are met. The

moratorium on taking does not apply to taking of marine mammals by Alaska Natives for

subsistence and handicraft purposes, when the taking is not wasteful.

The conditions for obtaining a waiver of the taking moratorium are procedurally burdensome and,

as a consequence, few waivers have been sought or granted. The Act was amended in 1981 and

again in 1986 to make it easier to obtain taking authorization when only small numbers of animals

will be taken, the taking is unintentional, and the effects on population size and productivity will be

negligible.

Section 101 (a)(5)(A) of the Act, as amended in 1986, directs the Secretaries of Commerce and the

Interior (the National Marine Fisheries Service and the U.S. Fish and Wildlife Service) to allow the

taking of small numbers of marine mammals incidental to activities (other than commercial fishing

covered by other provisions of the Act) for periods of up to five years if, after notice and opportunity

for public comment, the Secretary

(i) finds that the total of such taking during each five-year (or less) period concerned will have

a negligible impact on such species or stock...; and

(ii) prescribes regulations setting forth

(I) permissible methods of taking pursuant to such activity, and other means of effecting

the least practicable adverse impact on such species or stock and its habitat, paying
21

particular attention to rookeries, mating grounds, and areas of similar significance, and

on the availability of such species or stock for subsistence uses [by Alaska Natives]; and

(II) requirements pertaining to the monitoring and reporting of such taking

The House of Representatives Report that explained the 1981 amendments referenced the dictionary

definition of “negligible” and indicated that the term “negligible impact” was intended to mean an

impact “so small or unimportant or of so little consequence as to warrant little or no attention.” The

explanation suggests that the negligible impact standard is intended to be more restrictive than the

“no significant impact” standard in the National Environmental Policy Act (NEPA). Thus, a finding

of no significant impact under the NEPA would not necessarily mean that the activity in question

would have a negligible impact on marine mammals and that taking authorization under the MMPA

is not required.

All forms of incidental taking, including lethal taking, may be authorized under section 101

(a)(5)(A) of the MMPA. A new provision, section 101 (a)(5)(D), was added to the Act in 1994 to

provide a streamlined mechanism for authorizing small takes of marine mammals when the taking

is by incidental harassment (unintentional disturbance) only.

Authorizations under section 101 (a)(5)(A) involve a two-step process: (1) promulgation of a finding

that the incidental taking will have negligible effects and regulations setting forth permissible

methods of taking and requirements for monitoring and reporting the taking; and (2) issuance of

letters of authorization (LOAs) for particular activities in accordance with the regulations.

Promulgation of regulations can take more than six months.

Authorization of incidental harassment under section 101 (a)(5)(D) does not require promulgation

of regulations. Rather, the responsible regulatory agency is required to determine, within 45 days

of receiving an application, whether the application makes the required showings, and, if it does, to

publish a proposed authorization and notice of availability of the application for public comment

in the Federal Register and in newspapers and appropriate electronic media in communities in the

area where the taking would occur. Then, after a 30-day comment period, the agency has 45 days

to make a final determination on the application.

Authorizations under section 101 (a)(5)(A) may be issued for periods up to five years. Authorization

under Section 101 (a)(5)(D) may be issued for no more than one year. In both cases, authorizations

may be renewed according to the specified procedures. Swartz and Hofman (1991) provide an

assessment of the intent and provisions of section 101 (a)(5)(A) as they relate to offshore oil and gas

development and other activities.

Given the aforementioned provisions of the Marine Mammal Protection Act, it follows that the

participants in this workshop should keep three basic questions in mind. They are

1. given the results of research and monitoring programs in the Gulf of Mexico or elsewhere,

is there reason to believe or to suspect that oil and gas exploration and development

activities in the northern Gulf of Mexico may be resulting in the taking of any species of
22

marine mammal (i.e., be causing the death, injury, or disruption of biologically important

behavior of any marine mammal species)?

2. if taking may be occurring, are the effects on the distribution, abundance, or productivity of

the affected species or populations negligible or non-negligible? and

3. if there are uncertainties concerning the nature or significance of the possible effects, what

research or monitoring is needed to resolve the uncertainties?

REFERENCES

House of Representatives. 1981. Marine Mammal Protection Act amendment. 1st session, 97th

Congress. Report NO. 97-228.

Swartz, S.L. and R.J. Hofman. 1991. Marine mammal and habitat monitoring requirements:

principles; needs; and approaches. NTIS PB91-215046. 18 pp.
23

THE ENDANGERED SPECIES ACT AND GULF OF MEXICO MARINE SPECIES

Mr. David Bernhart

Fishery Biologist

Protected Resources Division

National Marine Fisheries Service

St. Petersburg, Florida

This paper provides a framework understanding of the Endangered Species Act (ESA) and of how

the statute shapes the responsibilities of all the players who may be affecting endangered and

threatened marine species in the Gulf. It is hoped that this understanding will be useful to developing

recommendations for future scientific activities relating to MMS’s management of oil and gas

development.

PLAYERS

The ESA’s requirements for managing listed species include a wide-range of players. The National

Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (FWS) are the federal

agencies charged with primary management responsibility for listed species. In the Gulf of Mexico,

six species of great whales, five species of sea turtles, and the Gulf sturgeon are listed as endangered

or threatened and under NMFS jurisdiction. All other federal agencies with activities in the Gulf also

have duties within their own range of authorities to conserve listed species and to minimize the

impacts of their actions on listed species. The MMS, U.S. Army Corps of Engineers, the Air Force,

and the Navy are some of the major federal actors in the Gulf, in terms of the breadth and scope of

their activities. Other federal agencies, such as the U.S. Coast Guard, the Environmental Protection

Agency, the U.S. Geological Survey, the National Park Service, and the Federal Energy Regulatory

Commission, also have roles in studying or protecting listed marine species, or conducting or

permitting activities that may affect them. Section 6 of the ESA allows states to form cooperative

agreements with NMFS to protect and manage endangered and threatened marine species, although

none of the coastal Gulf states have yet done so. Industry, of course, is also heavily involved with

protected species activities, both through their regulatory requirements and through their own

initiatives. We also depend on academia to conduct much of the critical scientific research to

understand these species’ threats and needs. Lastly, the ESA has special provisions which allow

“any person” to become involved in endangered species issues.

IMPORTANT PARTS OF THE ESA

Section 4 - Determination of Endangered and Threatened Species

Section 4 is the starting point for the protection and recovery of a species. It specifies the procedures

and requirements for listing a species as threatened or endangered. It also lays out how to designate

critical habitat for a species. Critical habitat, as used in the ESA, has a particular meaning, and then

only has meaning in relation to one other section of the ESA. No critical habitat has been designated

for listed marine species in the Gulf. Once species are listed, section 4 requires that recovery plans
24

be created for most species. The recovery plans set out goals to be achieved to bring about a species’

recovery and de-listing. They also recommend the tasks needed and specify who is to accomplish

them. (Recovery plans have been completed for the five species of Gulf sea turtles, the Gulf

sturgeon, and the blue whale.) Lastly, when species are listed as threatened (but not endangered),

special regulations can be enacted under section 4(d) – “a 4(d) rule” – that lay out what protections

these threatened species require. These 4(d) rules are commonly used to extend most of the ESA’s

full protections for endangered species to threatened species, while carving out a few exceptions.

One well-known application of a 4(d) rule in the Gulf of Mexico is the exception that allows

shrimpers incidentally to capture threatened sea turtles, as long as they use turtle excluder devices.

Section 9 - Prohibited Acts

Virtually every law has its list of prohibitions, and the ESA is no exception. The one of primary

concern is the blanket prohibition of any kind of “take” of an endangered species. The definition of

take in the ESA includes “to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect”

or to attempt to do any of those. Importantly, the take prohibition includes non-intentional, or

incidental, takes as well. Section 9 also prohibits any violations of the special protective regulations

for threatened species (4(d) rules).

Section 7 - Interagency Cooperation

The ESA includes special duties and responsibilities for all federal agencies to help carry out the

purposes of the ESA. These are spelled out in section 7. Section 7 applies only to federal agencies,

but it is probably the most relevant part with respect to our meeting. Therefore, I will focus briefly

on two of section 7's most important parts.

All federal agencies have a duty to take positive actions to conserve endangered and threatened

species. Section 7(a)(1) of the ESA provides that "...federal agencies shall, in consultation with and

with the assistance of [NMFS or FWS], utilize their authorities in...carrying out programs for the

conservation of threatened and endangered species... ." This language has long been considered to

represent simply a generalized policy, rather than a concrete obligation. A recent court ruling,

however, has emphasized that federal agencies do have an affirmative responsibility to take action

to conserve listed species (see Sierra Club vs. Glickman, U.S. 5th Circuit Court of Appeals, Sept.

1998).

Federal agencies have a further duty to examine the effects of their actions on listed species; this

process is called section 7 consultation. Section 7(a)(2) of the ESA requires every federal agency,

in consultation with NMFS and/or FWS, to ensure that any action it authorizes, funds, or carries out

is not likely to jeopardize the continued existence of any listed species. As part of the consultation

process, NMFS would review the agency action and issue a “biological opinion” about whether

jeopardy to any listed species is likely. If a “no-jeopardy” finding is reached, then the biological

opinion would also include an incidental take statement (ITS) that would authorize a small level of

incidental take of listed species, while requiring the federal agency or their permit applicant to take

specified measures to reduce the impact of the take. For listed species of marine mammals,

incidental take can only be authorized if the more stringent requirements of section 101(a)(5) of the
25

Marine Mammal Protection Act (MMPA) have been met as well. An ITS provides an important

exception to the prohibition on takes in section 9, as long as the terms and conditions of the ITS are

implemented. If an agency action is determined likely to jeopardize any listed species, then the

activity may not proceed and no incidental take would be authorized, unless a no-jeopardy

alternative is specified. Very few agency actions result in jeopardy biological opinions, however.

The section 7 consultation process actually provides for a great deal of flexibility and cooperation

between the action agency and NMFS or FWS, so impacts may be identified and minimized in

advance, to prevent jeopardy to listed species and adverse changes to the project. Section 7

consultation can also be a fairly dynamic process; many consultations are re-opened and modified,

as the projects change or new information on the impacts of the projects or the needs of the species

becomes available.

NMFS and MMS have completed two important consultations relating to Gulf of Mexico marine

species. In a July 1988 biological opinion, NMFS concluded that oil rig abandonment and explosive

rig removals in the OCS were not likely to jeopardize any listed species under NMFS jurisdiction.

That opinion considered the effects of a “generic” explosive rig removal, in which the manner of

the explosive removal was constrained to what was then considered typical and relatively safe for

marine animals. The requirements of the ITS focus on monitoring and minimizing the impacts of

individual removals. The opinion is over 10 years old and is still in effect, but NMFS and MMS

have been discussing reinitiating the consultation to also consider the effects of other, non-generic

blasting configurations. The 1988 opinion also doesn’t apply to rig removals in the territorial sea,

where removal permits are issued by the states or the Corps of Engineers. More recently, in January

1998, NMFS issued a no-jeopardy biological opinion on MMS’ 5-year lease sale plans for the

Western and Central Gulf Planning Areas. Biological opinions have to consider all the direct and

indirect effects of an action, so this opinion considered all OCS oil and gas exploration and

development activities (except rig removals). Since the scope of the opinion was so wide, the

requirements of the ITS focus more on monitoring the Gulf-wide status of affected species

(specifically their overall numbers and health) and on addressing data needs.

Section 10 - Exceptions

Section 7 consultation can provide for an important exception to the prohibition on incidental take

of listed species, but section 7 does not apply to non-federal activities, nor to cases of directed take

of listed species. Section 10 of the ESA provides for permits that can authorize those types of takes.

Permits can be granted for the directed take of a listed species for scientific research purposes and

for activities to enhance the species’ survival (“10(a)(1)(a) permits”). Permits can be granted to nonfederal applicants, who do not have access to section 7, to incidentally take listed species during the

course of an otherwise lawful activity (“10(a)(1)(b) permits”). The applicants are required to

minimize and mitigate their impacts, often by setting aside habitat, and these permits are commonly

called Habitat Conservation Plans (HCPs). HCPs are not widely used in the marine environment,

because many activities are federally authorized and section 7 would apply.
26

The Endangered Species Act

and Gulf of Mexico

Marine Species

David Bernhart

Protected Resources Division

Southeast Regional Office

National Marine Fisheries Service

ESA Players in the Gulf

• Federal

– Actors / Managers

• U.S. Fish and Wildlife Service (the Secretary of the Interior

• National Marine Fisheries Service (the Secretary of Commerce

– Actors

• All Other Federal Agencies

– Primarily MMS, COE, and DOD

– Others USGS, NPS, EPA, FERC, USCG

• States

– through Cooperative Agreements with FWS or NMFS

• Industry

• Academia

• “Any Person”

• Gulf of Mexico

Section 11 - Penalties and Enforcement

The ESA allows violators to be fined through civil proceedings or to be criminally prosecuted, with

maximum penalties of $25,000 or $50,000, respectively. In addition to penalties that can be sought

by the government, the ESA includes a citizen suit provision in section 11(g). Any person may sue

any other person, including the U.S. government, for violating any section of the ESA. These suits

may seek an injunction to stop an activity that violates the ESA. A common use of these suits is to

compel federal agencies to conduct section 7 consultation. The citizen suit provision has been

heavily used in the courts, primarily by environmental NGOs.

Section 17 - Construction with the MMPA

Probably the most obscure section of the ESA is section 17, but it is relevant to our meeting because

one of the more important marine mammals in the Gulf—the sperm whale—is protected by both the

MMPA and the ESA. Section 17 states that the ESA does not take precedence over the MMPA,

where the MMPA’s provisions are more restrictive. In other words, for listed species of marine

mammals, both acts must be complied with, including the most restrictive requirements.

PRESENT GOALS

For MMS, the most immediate needs are to implement the requirements of the existing biological

opinions and incidental take statements. Looking to the future, information will be needed to support

consultations on changes to existing activities, such as different methods for oil rig removals, or for

consultations on new activities, such as expansion of oil and gas development into the eastern Gulf.

SLIDE SHOW
27

Endangered and Threatened

Species Under National Marine

Fisheries Service Jurisdiction

blue whale Balaenoptera Musculus Endangered

fin whale Balaenoptera physalus Endangered

humpback whale Megaptera novaeangliae Endangered

right whale Eubalaena glacialis Endangered

sei whale Balaenoptera borealis Endangered

sperm whale Physeter macrocephauls Endangered

green sea turtle* Chelonia mydas Endangered/ Threatened

hawksbill sea turtle* Eretmochelys imbricata Endangered

Kemps ridley turtle* Lepidochelys kempii Endangered

leatherback turtle* Dermochelys coriacea Endangered

loggerhead sea turtle* Caretta caretta Threatened

gulf sturgeon* Acipenser oxrinchus desotoi Threatened

* Joint jurisdiction with U.S. Fish and Wildlife Service

Important Parts of the ESA

• Section 4 - Determination of

Endangered and Threatened Species

• Section 7 - Interagency Cooperation

• Section 9 - Prohibited Acts

• Section 10 - Exceptions

• Section 11 - Penalties and Enforcement

Section 4 of the ESA

• How to list species as endangered or

threatened

• How to list critical habitat

• Recovery Plans required

• Protective regulations for threatened

species can be issued

Section 9 of the ESA

• “Take” of endangered species is

prohibited

– Includes to harass, harm, pursue, hunt,

shoot, wound, kill, trap, capture, or collect,

or attempt

– Includes incidental take as well

• Violation of protective regulations for

threatened species is prohibited

Section 7 of the ESA

• Applies to federal agencies

• 7(a)(1) - Conservation Requirement

– “. . .Federal agencies shall, in consultation

with and with the assistance of the

Secretary, utilize their authorities in . . .

carrying out programs for the conservation

of threatened and endangered species . . .

• Positive obligation, recently verified by

the courts

Section 7 of the ESA

• 7(a)(2) - Consultation Requirement

– Requires every Federal agency, in consultation with NMFS and/or

FWS, to ensure that any action it authorizes, funds, or carries out is

not likely to jeopardize the continued existence of any listed species

• NMFS/FWS reviews the “agency action” and

issues a Biological Opinion whether jeopardy is

likely

• No-Jeopardy Biological Opinions include an

Incidental Take Statement

– Authorizes a small level of incidental take of listed species

– Requires measures to minimize the impacts of the take

– For Marine Mammals, take must be authorized through MMPA, too

• Jeopardy actions may not go forward unless a nojeopardy alternative is found
28

Section 7 of the ESA

• Oil Rig Abandonment / Explosive Rig Removal

– July 1988 No-Jeopardy Biological Opinion

– Considered effects of a “generic” rig removal process in the OCS

– ITS requirements focus on monitoring removals

– Doesn’t apply to territorial sea or non-generic removals

– Informal consultation has been ongoing to consider non-generic

removals

• Lease Sales

– January 1998 No-Jeopardy Biological Opinion

– Considered 5-year lease sales in Western and Central Gulf

• Includes resulting OCS activities (except explosive rig removals)

– ITS requirements focus on species monitoring (numbers and

health) and data needs

Section 10 of the ESA

• 10(a) - Take Permits

• 10(a)(1)(a) - Authorizes scientific research or

enhancement activities

• 10(a)(1)(b) - Authorizes incidental take of

listed species

– Available to non-Federal applicants

– Requires applicant to minimize and mitigate impacts

– Often called Habitat Conservation Plans (HCPs)

– Not widely used in the marine environment, because Section

7 affects most activities

Section 11 of the ESA

• Sets penalties for violations

– Civil $25K

– Criminal $50K

• Authorizes Citizen Suits

– Any person may sue any person (including

the U.S. Government) for violating the ESA

– Can include violation of any section

Section 17 of the ESA

• The ESA does NOT take precedence

over more restrictive provisions of the

MMPA
29

BIOLOGY

GULFCET I AND II – CETACEANS, SEA TURTLES

AND HABITAT CONSIDERATIONS

Dr. Keith D. Mullin

National Marine Fisheries Service

Pascagoula, Mississippi

Dr. Randall W. Davis

Department of Marine Biology

Texas A&M University

The GulfCet I and GulfCet II programs resulted from cooperative research between the MMS Gulf

of Mexico Region, the NMFS Southeast Fisheries Science Center and Texas A&M University.

GulfCet I, 1991-95, was a seasonal study of cetacean and sea turtle distribution in U.S. continental

slope waters (100-2,000 m) of the north-central and northwestern Gulf (Davis and Fargion 1996).

GulfCet II, 1996-98, was a continuation of this seasonal research and focused on slope waters of the

northeastern Gulf and selected continental shelf waters (<100 m) south of the western Florida

Panhandle. An additional aspect of GulfCet II was a replication of spring abundance surveys of the

oceanic northern Gulf conducted by the SEFSC from 1991-1994 (Hansen et al. 1995). In addition

to GulfCet surveys, the SEFSC has conducted fall aerial surveys of the entire continental shelf in

the northern Gulf (Blaylock and Hoggard 1994) and a summer ship survey of the western Florida

continental shelf. Distribution and abundance data were collected during both aerial and ship surveys

using line-transect methods (Buckland et al. 1993).

To characterize cetacean habitats during GulfCet I and II, hydrographic data were collected during

ship surveys. Two ship surveys were conducted during GulfCet II to simultaneously collect cetacean

location data and data on the marine environment and zooplankton biomass (acoustic and net

sampling) in an area containing a cyclone-anticyclone. Satellite remote sensing data for sea surface

height (SSH) anomaly and GulfCet I and II cetacean sighting locations were combined to examine

the relationship between cetacean distribution and hydrographic features. Relationships to ocean

depth and ocean depth gradient were also examined.

CETACEAN DIVERSITY, ABUNDANCE AND DISTRIBUTION

In the northern Gulf, the continental shelf and shelf-edge is inhabited almost exclusively by

bottlenose and Atlantic spotted dolphins. Bottlenose dolphins are widely distributed in all shelf

waters but genetic studies indicate species level differences between nearshore and offshore animals

(LeDuc and Curry 1998). Atlantic spotted dolphins usually are not found in waters less than about

10 m deep, and while widely distributed, appear to be more common off Florida. 
30

The primary findings from GulfCet I and II indicate that the oceanic cetacean community is

composed primarily of tropical species that usually inhabit deep waters (Jefferson et al. 1993). The

oceanic studies generally indicate the following: 

1. Cetaceans are diverse. There are at least 20 species that range from being uncommon to very

abundant. Other species with records from the Gulf are probably very rare (e.g., humpback,

minke, blue, sei, right whales) or extralimital (Sowerby’s beaked whale). There are no valid

records of common dolphins from the Gulf (Jefferson 1995). 

2. The pantropical spotted dolphin is the most abundant species with an estimated minimum

of 30,000-40,000 dolphins. The abundances of both spinner dolphins and Clymene dolphins

ranged from 6,000-12,000. The abundances of bottlenose dolphins, Risso’s dolphins, striped

dolphins, and melon-headed whales ranged from 1,500-5,500, and those of other species,

<1,000.

3. The sperm whale (400-550 animals) and Bryde’s whale (<50 animals) are the only large

whales routinely sighted in the Gulf. While less abundant than the delphinids, the sperm

whale may be at least as ecologically significant because of its size and was estimated to

comprise about 44% of the cetacean biomass in the oceanic northern Gulf.

4. Most species are present throughout the year and, at least in spring, are widely distributed

in the oceanic northern Gulf.

5. The abundance of some species (e.g., dwarf/pygmy sperm whale, Risso's dolphin, bottlenose

dolphin, pantropical spotted dolphin) may vary seasonally in continental slope waters.

6. The abundance of some species appears to vary east to west. Bryde’s whales, false killer

whales, pantropical spotted dolphins and spinner dolphins have been sighted more frequently

to the east of the Mississippi River delta. Conversely, short-finned pilot whales, melonheaded whales, and Clymene dolphins are typically sighted to the west of the river. 

OCEANIC CETACEAN HABITATS

Of six hydrographic and physiographic features used to define species habitat during GulfCet I, only

bottom depth provided the clearest differentiation. Atlantic spotted dolphins were consistently found

in the shelf break region. Bottlenose dolphins generally inhabited waters of the shelf break to upper

slope. Risso’s dolphins and short-finned pilot whale occurred along the mid- to upper slope. On

average, pygmy/dwarf sperm whales, spinner dolphins and sperm whales occurred at intermediate

depths. Striped dolphins, beaked whales, pantropical spotted dolphins and Clymene dolphin

inhabited the deepest waters (Davis et al. 1998). With a few exceptions, Bryde's whales have been

found along a narrow corridor near the 100 m isobath in the northeastern Gulf. Killer whales range

throughout the northern Gulf, but most sightings occurred in a broad region just southwest of the

Mississippi River Delta. Results from the combined GulfCet I and II data were similar to GulfCet

I. While distributed throughout the oceanic northern Gulf, Baumgartner (1997), demonstrated that
31

Risso's dolphins have a core habitat along the upper continental slope defined by depth and depth

gradient. This core habitat makes up about 2% of the entire Gulf.

Cetaceans in the northeastern and oceanic northern Gulf were concentrated along the continental

slope in or near cyclones. These eddies are mesoscale features with locally concentrated zooplankton

and micronekton stocks that appear to develop in response to increased nutrient-rich water and

primary production in the mixed layer. The exceptions were bottlenose dolphins, Atlantic spotted

dolphins and possibly Bryde's whales. These species typically occur on the continental shelf or along

the shelf break outside of the major influences of eddies. While endangered sperm whales are widely

distributed in the northern Gulf, there appears to be a resident population south of the Mississippi

River delta. This may be explained by low salinity, nutrient-rich water from the Mississippi River,

which may also contribute to enhanced primary and secondary productivity in the north-central Gulf.

However, since cyclones in the northern Gulf are dynamic, cetacean distribution will undoubtedly

change in response to the movement of prey associated with these hydrographic features.

SEA TURTLE DIVERSITY, ABUNDANCE AND DISTRIBUTION

Five species of sea turtles occur in the Gulf: leatherback, loggerhead, Kemp’s ridley, green and

hawksbill. All five species have been sighted during SEFSC fall shelf and GulfCet aerial surveys,

but results pertain only to large, probably adult, turtles visible from aircraft at the surface of water.

In shelf waters loggerheads are widely distributed throughout the northern Gulf but the frequency

of sightings increased dramatically in the eastern Gulf. The density of loggerheads in the

northeastern Gulf was about 20 times greater in shelf waters (4.08 turtles/100 km2

) compared to

slope waters (0.20 turtles/100 km2). Summer and winter densities of loggerheads were similar in

shelf waters but were about 10 times larger during winter in slope waters. Loggerheads were about

four times more abundant in continental slope waters in the northeastern Gulf compared to the northcentral and northwestern Gulf. The majority of leatherback sightings in shelf waters were just north

of DeSoto Canyon in the northeastern Gulf. Leatherbacks were widely distributed in slope waters

throughout the northern Gulf, but there were areas of high concentrations of turtles that were

variable in distribution. The overall density of leatherbacks was 0.24 turtles/100 km2 in slope waters

of the northeastern Gulf and 0.18 turtles/km2 in the northwestern Gulf. Seasonal densities of

leatherbacks were similar in slope waters west of Mobile Bay but more variable to the east.

Sightings of hawksbill and green turtle occurred in shelf waters primarily off southern Florida.

ON-GOING CETACEAN STUDIES

In 1998, the MMS and the SEFSC initiated a three-year cetacean abundance monitoring program

of U.S. Gulf shelf and oceanic waters (the program has been extended through FY 2002). This

program provides for ship surveys of oceanic waters during spring, and shelf waters during the fall.

These surveys are “piggy-backed” on SEFSC ichthyoplankton surveys and, therefore, costs are

primarily limited to observer salaries. The fall 1998 shelf survey was heavily impacted by hurricanes

but the spring 1999 oceanic survey was extremely successful.
32

FUTURE CETACEAN RESEARCH NEEDS

Research with Existing Abundance and Distribution Data

1. The current abundance estimates of cetacean species for the oceanic northern Gulf may be

biased because the survey effort does not appear be completely random or uniform in

distribution. More accurate abundances may be obtained by making area-weighted estimates

from a grid of cells. Similarly, current distribution plots may not represent the true

distribution of animals due to the distribution of effort and variability in group-size. Density

contours could be generated from the grid for common species which would provide more

useful information concerning the area where each species would most likely be

encountered.

2. To provide more precise estimates of abundance and improve the probability of detecting

changes in abundance for a species over time, an attempt could be made to use data only

from a species’ primary habitat for estimates (e.g., Reilly and Fielder 1994). At this time,

depth ranges (and perhaps longitude) could be considered. 

3. Aerial survey results from GulfCet I and II indicated that abundances of several species may

change seasonally; however, most differences were not statistically different. A recent more

powerful statistical test could be employed to reexamine these seasonal data for significant

differences (Forney and Barlow 1998).

4. While all of the current abundance estimates are negatively biased due to perception bias

(animals missed by observers) and availability bias (animals beneath the surface), the

perception bias is probably greater for cryptic species such as beaked whales and

dwarf/pygmy sperm whales. Reanalyses of data using only excellent sighting conditions

would give a better indication of the abundance of these species relative to others. 

Suggested Future Research

1. Research the genetic stock structure, movements, diving behavior and site fidelity of

endangered sperm whales.

2. Continued monitoring of cetacean populations in the northern Gulf during the NMFS

ichthyoplankton surveys.

3. Research on the effects of seismic sounds on cetaceans.

4. Initiate a GulfCet III Program for the U.S. water south of Tampa Bay and the southern Gulf

of Mexico (south of the U.S. Economic Exclusive Zone), including the Straits of Florida. 

5. Research on cetacean habitat-associations should continue. If shifts in a species' distribution

occur, a better understanding of habitat will be needed.
33

6. Research on genetic stock structure of all cetaceans should be given added emphasis. The

MMPA mandates that stocks of cetaceans be protected. Of particular interest are Bryde's

whales which have displayed considerable local variation world-wide (Dizon et al. 1995)

and appear to have a limited distribution in the northern Gulf.

7. Research to estimate absolute abundances. That is, correct minimum abundances for

perception bias (observer bias) and availability bias (beneath the surface) with data from

independent observer experiments and dive time studies.

REFERENCES

Baumgartner, M.F. 1997. The distribution of Risso’s dolphin (Grampus griseus) with respect to the

physiography of the northern Gulf of Mexico. Marine Mammal Science 13:614-638.

Blaylock, R.A. and W. Hoggard. 1994. Preliminary estimates of bottlenose dolphin abundance in

southern U.S. Atlantic and Gulf of Mexico continental shelf waters. NOAA Technical

Memorandum NMFS-SEFSC-356, 10pp.

Buckland, S.T., D.R. Anderson, K.P. Burnham and J.L. Laake. 1993. Distance sampling: Estimating

abundance of biological populations. Chapman and Hall, London. 446 pp.

Davis, R.W. and G.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. 357pp.

Davis, R.W., G.S. Fargion, N. May, T.D. Leming, M. Baumgartner, W.E. Evans, L.J. Hansen and

K.D. 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.

Dizon, A.E., C. Lockyer, W.F. Perrin, D.P. DeMaster and J.E. Sisson. 1992. Rethinking the stock

concept: a phylogeographic approach. Conservation Biology 6:24-36.

Dizon, A., C. L. Lux, S. Costa, R. LeDuc and R. Brownell, Jr. 1995. Phylogenetic relationships of

the closely related sei and Bryde's whale: A possible third species? Abstract. Eleventh biennial

conference on the biology of marine mammals. 14-18 December 1995, Orlando, Florida USA.

Forney, K.A. and J. Barlow. 1998. Seasonal patterns in the abundance and distribution of California

cetaceans, 1991-1992. Marine Mammal Science 14:460-489.

Hansen, L.J., K.D. Mullin and C.L. Roden. 1995. Estimates of cetacean abundance in the northern

Gulf of Mexico from vessel surveys. Contribution No. MIA-94/95-25. Southeast Fisheries Science

Center, Miami Laboratory, 75 Virginia Beach Drive, Miami, Florida 33149.
34

Jefferson, T.A., S. Leatherwood and M.A. Webber. 1993. FAO species identification guide. Marine

mammals of the world. Rome, FAO. 320 pp.

Jefferson, T.A. 1995. Distribution, abundance, and some aspects of the biology of cetaceans in the

offshore Gulf of Mexico. Ph.D. dissertation. Texas A&M University. 232 pp.

LeDuc, R.G. and B.E. Curry. 1998. Mitochondrial DNA sequence analysis indicates need for

revision of the genus Tursiops. Report of the International Whaling Commission 47:393.

Reilly, S.B. and P.C. Fiedler. 1994. Interannual variability of dolphin habitats in the eastern tropical

Pacific. I: Research vessel surveys, 1986-1990.

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.

Dr. Randall Davis, has been a professor in the Department of Marine Biology at Texas A&M

University since 1989. He was formerly a research physiologist at Sea World Research Institute in

San Diego. Dr. Davis received his Ph.D. in physiology from University of California, San Diego.
35

MANATEES IN THE GULF OF MEXICO

Dr. Robert K. Bonde

Dr. Lynn W. Lefebvre

United States Geological Survey, Biological Resources Division

Florida Caribbean Science Center, Sirenia Project

Gainesville, Florida

The endangered Florida manatee (Trichechus manatus latirostris) inhabits rivers and estuaries along

both coasts of Florida and, to a lesser extent, adjacent states (Figure 1). Since 1990, documented

sightings of manatees outside of Florida have been increasing. This increase in sightings probably

represents northward shifts in manatee distribution made possible by man-made sources of warm

water (i.e., industrial effluents), as well as a decade of relatively warm winters. The most likely

source of emigrants on the Gulf coast is the population of manatees that overwinter in the

headwaters of the Crystal and Homosassa Rivers, Citrus County, FL. This group of manatees has

undergone a steady increase in numbers, (approximately 7% per year from 1977-1991; Eberhardt

and O’Shea 1995). Some emigrants may also come from the Tampa-Ft. Myers region, where human

impacts on habitat are greater. Manatees are intelligent, long-lived mammals that appear to adapt

readily to new environments and situations. However, manatees have relatively low metabolic rates,

and cold winter temperatures restrict their northern distribution.

RESEARCH 

Research on manatees has increased dramatically over the last two decades. Research is conducted

by federal, state and local governments, as well as several oceanaria and academic institutions. The

Sirenia Project is a team of U.S. Geological Survey biologists that conducts long-term, detailed

studies on the life history, population dynamics, and ecological requirements of the West Indian

manatee (Trichechus manatus). Two federal laws (the Marine Mammal Protection Act of 1972 and

the Endangered Species Act of 1973) and a state law (the Manatee Sanctuary Act of 1978) protect

the manatee. The Florida Manatee Recovery Plan, prepared by an interagency team under the

direction of the U.S. Fish and Wildlife Service, guides manatee research and management activities.

Sirenia Project personnel serve as representatives on the Manatee Recovery Team. Project personnel

also are active members in several working groups established by the Recovery Plan to coordinate

research and management objectives for assessment of manatee population status, development of

GIS applications, and evaluation of captive manatee releases. 

The Sirenia Project has pioneered several important tools for manatee research, most notably

development of a computerized photo-identification catalog, a radio tag assembly for tracking

manatees by satellite in fresh or salt water, food habits and age determination techniques, assessment

of manatee grazing impacts on seagrasses, survival estimation methods, and integration of life

history data and population modeling. Project personnel also have been involved in developing and

testing aerial survey techniques for manatees. Current research projects include (1) continued

improvement of the photo-identification system and its application to estimation of manatee survival

and reproductive parameters; (2) documentation of databases and protocols to meet metadata
36

Current Status of the

Florida Manatee

REGIONS

Northwest ( (

Upper St.

Johns River (

Atlantic Coast ;

Tampa Bay and

Southwest ?

Current Status of the

Florida Manatee

REGIONS

Northwest ( (

Upper St.

Johns River (

Atlantic Coast ;

Tampa Bay and

Southwest ?

Figure 1. Current status of the Florida manatee.

standards for biological data; (3) analysis of radio tracking data to determine patterns of movement

and habitat use; (4) evaluation of releases of captive-born and captive-reared manatees; (5) seagrass

ecology and manatee diet in selected high-use habitats; (6) radio tracking and habitat

characterization in areas important to manatees in Puerto Rico; (7) genetic analysis and manatee

population structure; (8) manatee use of thermal refugia and response to their elimination; and (9)

international information and technology transfer.

STATUS ON THE WEST COAST OF FLORIDA

Most of the information on manatees has been gathered from long-term studies conducted in Florida;

life history research in northwest Florida has been ongoing for over 30 years. Aerial survey data

collected by the U. S. Fish and Wildlife Service demonstrate a steady increase in the usage of the

thermal refugia located in the Crystal and Homosassa Rivers (Figure 2). The spring-fed winter

refugia at the headwaters of these two rivers, and other smaller springs, offer thermal protection

during cold weather. Abundant vegetation, fresh water flowing from the many rivers and creeks, and

a relatively small human population along the northeastern Gulf of Mexico provide both winter and

warm-season habitat for manatees. The probability of annual adult survival (96%) and reproduction

(36% of adult females with first-year calves) are high enough in this region to maintain a growing

population (Langtimm et al. 1998; Rathbun et al. 1995). Overall mortality and deaths caused by

collisions with watercraft are relatively low.
37

Maximum winter aerial survey counts at

Crystal and Homosassa Rivers 1984-99

140 128 134

204 201

220

286 280

260

286 270

299 303 297

367

335

100

150

200

250

300

350

400

1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999

Figure 2. Maximum winter aerial survey counts at Crystal and Homosassa Rivers 1984-99.

Carcass salvage, telemetry, life history, and aerial survey data have been collected for the Tampa

Bay-Ft. Myers region by researchers with the Florida Marine Research Institute- Department of

Environmental Protection, Mote Marine Laboratory, and Eckerd College. Although survival and

reproduction estimates are not yet available for this region, there is evidence of population growth

in this region, particularly for the group that overwinters in Tampa Bay (B.B. Ackerman, Florida

Marine Research Institute, pers. comm.). However, the number of manatee deaths is high in this

region, particularly those caused by watercraft. 

Very little is known about manatee status in the Ten Thousand Islands and Everglades National Park

region of the Gulf Coast. Some aerial survey data (Everglades National Park and Florida Marine

Research Institute) and radio tracking data (Florida Marine Research Institute and U.S. Geological

Survey) have been collected.

THREATS 

Deaths due to collisions with boats are the number one cause of human-related manatee mortality

in the southeastern United States (Figure 3). As the human population in Florida increases, so does

the number of human-related manatee deaths. The growth of the human population also has lead to
38

Causes of Florida Manatee Mortality: 

1974 - 1997

Watercraft

23%

Flood Gate / 

Lock

4%

Perinatal

21%

Other Natural

17%

Other Human

3%

U ndetermined

32%

Source: Florida Dept. of Environmental Protection

Figure 3. Causes of Florida Manatee Mortality: 1974-1997.

increased habitat degradation and perhaps has forced manatees to range beyond historic limits in

search of suitable habitat. 

Manatees are semi-tropical mammals that do not fare well in the cooler winter habitats of northern

Florida and other Gulf states. Manatees need warm water during cold weather (ambient water

temperatures < 18<C), thus the region along the Gulf of Mexico to the west of Florida does not

contain suitable winter habitat for manatees. Deregulation of the power-generating industry in

Florida may result in erratic operation of power plants and could leave manatees “out in the cold”

if they shut down during critically cold periods. This may limit the distribution of manatees into

other Gulf Coast states. 

In 1982 and 1996, toxic red tides (Gymnodinium breve blooms) caused significant manatee mortality

in southwest Florida. Hurricanes and severe storms can impact manatee habitat by increasing salinity

in inland waters, causing declines in the availability of freshwater vegetation upon which manatees

feed. Conversely, large volumes of freshwater input to marine and estuarine manatee habitats can

kill seagrasses, another important manatee food resource. Human impacts on water quality and

quantity degrade manatee habitat. For example, there is evidence of reduced flow rates at some of

the major springs used by manatees as thermal refugia. Human disturbance at major winter

aggregation sites may affect manatee survival or reproduction, although no such impacts have yet
39

been detected. Lack of genetic heterogeneity makes manatees more vulnerable to inevitable changes

in the coastal environment.

RESEARCH NEEDS

1. Continue to collect basic life history information and expand data collection sites to include

the panhandle and the Ten Thousand Islands (TTI) and Everglades National Park (ENP).

2. Analyze life history information to determine manatee population status for the entire Gulf

Coast.

3. Collate existing aerial survey and telemetry data for TTI-ENP to develop a model that will

predict manatee response to different South Florida ecosystem restoration scenarios.

4. Initiate radio tracking and other field studies in TTI-ENP that will provide data for the

restoration model and population status determination.

5. Initiate radio tracking and other field studies that will provide data on warm-season manatee

habitat use in the Big Bend and panhandle regions of Florida. 

6. Continue genetic studies to determine manatee population structure.

REFERENCES

Eberhardt, L.L. and T.J. O’Shea. 1995. Integration of manatee life-history data and population

modeling. Pp. 269-279. In T. J. O’Shea, B.B. Ackerman, and H.F. Percival, eds., Population

Biology of the Florida Manatee (Trichechus manatus latirostris). National Biological Service,

Information and Technology Report 1. 289 pp.

Langtimm, C.A., T.J. O’Shea, R. Pradel, and C.A. Beck. 1998. Estimates of annual survival

probabilities for adult Florida manatees (Trichechus manatus latirostris). Ecology 79(3):981-

997.

Rathbun, G.B., J.P. Reid, R.K. Bonde, and J.A. Powell. 1995. Reproduction in free-ranging Florida

manatees. Pp. 135-156. In T. J. O’Shea, B.B. Ackerman, and H.F. Percival, eds., Population

Biology of the Florida Manatee (Trichechus manatus latirostris). National Biological Service,

Information and Technology Report 1. 289 pp.

Bob Bonde has been a Biologist with the USGS Biological Resources Division, Sirenia Project for

the past 20 years. He has 25 years’ experience with necropsy, 13 years’ experience with radio

tracking, and 15 years’ experience with field observation and life history studies. He has flown over

38,000 miles of manatee aerial surveys in Florida and has done manatee and dolphin distribution

surveys in Puerto Rico, Panama, Mexico, and Belize. He has captured, radio tagged, and tracked
40

manatees in Florida, Puerto Rico, Mexico, and Belize using conventional VHF, satellite-monitored

UHF, and sonic techniques.

Lynn W. Lefebvre is a wildlife biologist with the U.S. Geological Survey's Biological Resources

Division at the Florida Caribbean Science Center in Gainesville, FL. She began working with

manatees in 1985 and has been the Sirenia Project Leader since 1992. Her research interests include

manatee feeding ecology, releases of long-term captive and captive-born manatees, and assessment

of anthropogenic impacts on manatee populations. Lynn received her B.A.A.S. degree in biology

at the University of Delaware, M.S. in wildlife management from the University of Massachusetts,

and Ph.D. in zoology at the University of Florida.
41

SEA TURTLES OF THE GULF OF MEXICO

Dr. Maurice L. Renaud

National Marine Fisheries Service

Information presented below, on sea turtle biology, is not intended, nor professed to be complete

or definitive. Its purpose is to serve as a cursory overview of selected aspects of sea turtle biology

in the Gulf of Mexico.

Five species of endangered or threatened sea turtles, afforded protection in U. S. waters under the

Endangered Species Act of 1973, inhabit the Gulf of Mexico. These are the Kemp's ridley

(Lepidochelys kempii), loggerhead (Caretta caretta), green (Chelonia mydas), hawksbill

(Eretmochelys imbricata) and leatherback (Dermochelys coriacea). These animals are free

swimming for almost all of their life but do occur on land as live or dead stranded animals, as

nesting females and as hatchlings scurrying to the sea from their nests. Once offshore hatchlings

become pelagic drifters. The length of the pelagic stage for Kemp’s ridleys is estimated at 1-2 years,

and 10-12 years for loggerheads. Information on early pelagic stages is not known for green,

hawksbill and leatherback sea turtles. However, since leatherbacks reach sexual maturity around the

same time as Kemp’s ridleys (10 years), they may also have a relatively short pelagic phase.

Kemp’s ridleys, loggerheads and leatherbacks are found along the entire Gulf coast (Figure 4).

Kemp’s ridleys, the shallowest of the three species, usually remain within 50-m depths, loggerheads

extend into deeper waters near reefs and platforms, and leatherbacks occur out to 2,000-m depths.

Green and hawksbill turtles occur off southwest Florida, Texas and Mexico (Figure 4).

Major nesting areas (>100 nests per season) of sea turtles in Gulf of Mexico are found at Rancho

Nuevo, Tamaulipas, Mexico for Kemp’s ridleys, along the southern and southwestern coasts of

Florida for loggerheads, and on the northern Yucatan Peninsula, Mexico for hawksbills (Figure 5).

Leatherback and green sea turtles have no major nesting sites in the Gulf of Mexico. All species of

sea turtles in the Gulf of Mexico nest to a lesser extent throughout the Gulf coast (Table 4). 

Many factors may influence sea turtle distributions in the Gulf of Mexico. Seasonal changes in water

temperature are well correlated with the presence and absence of sea turtles. Turtles are found along

the U.S. Gulf coast beginning in the spring (April and May) and remain there through the fall (SeptOctober). Depending on how soon spring waters warm up and how long they remain warm in the

fall, turtles may arrive in coastal areas as soon as February or March and remain as late as December

(Landry et al. 1993, 1994, 1995). In fact, during mild winters with minimal or no freezing events,

green turtles in south Texas have been known to overwinter (Arms 1996). Little is known

concerning the whereabouts of sea turtles after they depart nearshore areas in the fall. In the absence

of data, it was suggested that turtles leave areas in the winter to get away from cold water and seek

out warmer environments. With the advent of satellite tracking technology, data are beginning to

be compiled which support the above hypothesis. Sea turtles tracked during the winter do move

offshore or toward more southerly latitudes where water temperatures are usually >17o

C. Seasonal
Figure 4. Sea turtle distributions in the Gulf of Mexico.
Figure 5. Major sea turtle nesting sites (>100 nests/year).
44

Table 4. Minor/Historical Nesting Sites of Sea Turtles in the Gulf of Mexico (<100 nests/ year).

Kemp’s Ridley Loggerhead Green Hawksbill Leatherback

Florida (Gulf) X X X X X

Alabama X

Mississippi X

Louisiana X

Texas X X X

Tamaulipas X X X X

Veracruz X X X X X

Tabasco X X X X

Campeche X X X X

Yucatan X X X X

migrations typically begin following the passing of cold front (Renaud and Carpenter 1994; Renaud

1995; Renaud et al. 1996). The stimulus to migrate may be a combination of the reduction of air and

water temperature.

Other important factors that influence the movements and migrations of sea turtles are the urge to

nest, the need to forage, and ocean depth. Although a gross over simplification, it can be said that

sea turtles migrate to their nesting sites as a result of changes in their levels of reproductive

hormones. Turtles do not nest every year, but when hormones elicit the production of egg follicles

and egg development, turtles migrate to their nesting site while other turtles with insufficient levels

of reproductive hormones remain in foraging areas. Sea turtles are mostly bottom feeders. Thus their

distribution is limited to areas where they can dive to the sea floor to feed, as well as, to areas where

their food sources occur. A high incidence of juvenile sea turtle foraging occurs along certain coastal

regions of the Gulf coast. Prime examples of known nursery areas for sea turtles in the Gulf of

Mexico are the Texas Laguna Madre, extending from the Texas-Mexico border to Mansfield Pass,

Texas for green turtles, Sea Rim State Park, Texas to Mermentau Pass, Louisiana and Cedar Keys,

Florida for Kemp’s ridleys.

Although sea turtles in the Gulf of Mexico are sympatric to some extent, each fits into a definite

niche. Habitat and food sources of these turtles are summarized below.

a. Kemp’s ridleys – nearshore, shallow water mostly <50 m (crabs, fish, barnacles and

gastropods)

b. loggerheads – geographic overlap with ridley, but extend out to depths approaching 2,000

m; occur near reefs and fixed structures in Gulf; omnivorous (crabs, sponge, jellyfish,

barnacles, gastropods, urchins, sea pens, grasses and seaweeds)

c. leatherback – juveniles occasionally shallow, but species occurs mostly in 100-2,000 meter

depths; omnivorous (tunicates, urchins, jellyfish, squid, fish, algae)
45

d. greens – occur on shallow reefs, shoals and lagoons; mainly herbivorous (marine grass and

algae), limited carnivory in juveniles

e. hawksbills – inhabit shallow water reefs and lagoons; omnivorous (sponges urchins,

barnacles, sea grass, algae, coral)

In the northern Gulf of Mexico, tracking studies have shown that Kemp’s ridley, loggerhead and

green sea turtles spend 90-95% of their time under water. Although individual submergence

variation occurs, there do not appear to be differences by species, turtle size or season of year

(Renaud and Carpenter 1994; Renaud 1995; Renaud et al. 1996). These values are similar to those

for adult green turtles in the Pacific (96%, Balazs 1994), adult post-nesting Kemp’s ridleys off

Mexico (96%, Byles 1989), juvenile loggerheads in near Cape Canaveral, Florida (96%, Kemmerer

et al. 1983) and Olive ridleys in the Pacific (88%, Byles and Plotkin 1994). Dive duration, on the

other hand, varies by species, size of turtle and season. In general, the larger the Kemp’s ridley,

loggerhead or green sea turtle, the longer it is capable of remaining submerged. Winter

submergences are significantly longer than submergences for other seasons. Submergence data are

not available for hawksbill or leatherback turtles in the Gulf of Mexico. Mean dive times may be

less than 15 minutes in the summer to over an hour in the winter.

We are encouraged about information gathered on sea turtles during the past 10 years. However,

though our knowledge has increased tremendously, we are not near a complete understanding of sea

turtle biology and ecology. Turtles are long-lived animals and our data cover only a minute segment

of their life span. Thus, we shouldn’t let our advances cloud the facts: our sample size is small, and

work needs to continue on all species of sea turtle in the Gulf of Mexico.

CONTACT INFORMATION

For Recovery Plans, contact

U.S. Fish and Wildlife Service

5430 Grosvenor Lane

Suite 110

Bethesda, MD 20814

1-800-582-3421

For Technical Memoranda, contact

National Technical Information Service (NTIS)

5285 Port Royal Road

Springfield, VA 22161

REFERENCES

Balazs, G. 1994. Homeward bound: satellite tracking of Hawaiian green turtles from nesting beaches

to foraging pastures. pp. 205-207. In Schroeder, B. and B. (Compilers). Proceedings of the

Thirteenth Annual Symposium on Sea Turtle Conservation and Biology. NOAA Technical

Memorandum NMFS-SEFC-341, 281 pp.
46

Byles, R. A. 1989. Satellite telemetry of Kemp's ridley sea turtle, Lepidochelys kempi, in the Gulf

of Mexico, p. 25-26. In Eckert, S. A., K. L. Eckert, and T. H. Richardson (Compilers)

Proceedings of the Ninth Annual Workshop on Sea Turtle Conservation and Biology. NOAA

Technical Memorandum NMFS-SEFC-232, 306 p.

Byles, R. A. and P. T. Plotkin. 1994. Comparison of the migratory behavior of the congeneric sea

turtles Lepidochelys olivacea and L. kempii. p. 39. In Schroeder, B. and B. (Compilers).

Proceedings of the Thirteenth Annual Symposium on Sea Turtle Conservation and Biology.

NOAA Technical Memorandum NMFS-SEFC-341, 281 pp.

Carr, A, Meylan, A, Mortimer, J, Bjorndal, K, and Carr T. 1982. Survey of sea turtle populations

and habitats in the western Atlantic. NOAA Technical Memorandum NMFS-SEFC-91, 82 p,

Dodd, C. K. 1988. Synopsis of the biological data on the loggerhead sea turtle Caretta caretta

(Linnaeus 1758). U. S. Department of Interior, Fish and Wildlife Service Biological Report

88(14), 110 p.

Fuller, D. A., A. M. Tappan and M. C. Hester. 1987. Sea turtles in Louisiana's coastal waters.

Louisiana Sea Grant College Program, 39 p.

Hirth, H. F. 1997. Synopsis of biological data on the green turtle, Chelonia mydas (Linnaeus 1758).

Fish and Wildlife Service, U.S. Dept. of Interior, Washington D.C. 120 p.

Kemmerer, A. J., R. E. Timko and S. B. Burkett. 1983. Movement and surfacing behavior patterns

of loggerhead sea turtles in and near Canaveral channel, Florida (September and October 1981).

NOAA Technical Memorandum NMFS-SEFC 112, 43 p.

Marquez-M, R. 1994. Synopsis of biological data on the Kemp's ridley turtle, Lepidochelys kempi

(Garman, 1880). NOAA Technical Memorandum NMFS-SEFSC-343, 91 p.

National Marine Fisheries Service and U. S. Fish and Wildlife Service. 1991. Recovery plan for U.

S. population of Atlantic green turtle (Chelonia mydas). National Marine Fisheries Service,

Washington, D.C., 52 p.

National Marine Fisheries Service and U. S. Fish and Wildlife Service. 1991. Recovery plan for U.

S. population of loggerhead turtle (Caretta caretta). National Marine Fisheries Service,

Washington, D.C. 64 p.

Nelson, D. A. 1988. Life history and environmental requirements of loggerhead turtles. U.S. Fish

and Wildlife Service Biological Report 88(23), TR EL-86-2 (Rev.), 34 p.

Ogren, L., F. Berry, K. Bjorndal, H. Kumpf, R. Mast, G. Medina, H. Reichart, and R. Witham

(Editors). 1989. Proceedings of the Second Western Atlantic Turtle Symposium. NOAA

Technical Memorandum NMFS-SEFC-226, 401 p.
47

Renaud, Maurice L. 1995. Movements and submergence patterns of Kemp's ridley turtles

(Lepidochelys kempii). Journal of Herpetology, 29(3):302-306.

Renaud, M. and J. Carpenter. 1994. Movements and submergence patterns of loggerhead turtles

(Caretta caretta) in the Gulf of Mexico determined through satellite telemetry. Bull. Mar. Sci.

55(1):1-15.

Renaud, M. L., J. A. Carpenter, J. A. Williams and A. M. Landry, Jr. 1996. Kemp's Ridley Sea

Turtle (Lepidochelys kempii) Tracked by Satellite Telemetry from Louisiana to Nesting Beach

at Rancho Nuevo, Tamaulipas, Mexico. Journal of Chelonian Conservation and Biology,

2(1):108-109.

U. S. Fish and Wildlife Service and National Marine Fisheries Service. 1992. Recovery plan for the

Kemp's ridley sea turtle Lepidochelys kempii. National Marine Fisheries Service, St. Petersburg,

Florida. 40 p.

U.S. Fish and Wildlife Service and National Marine Fisheries Service. 1992. Recovery plan for

leatherback turtles in the U.S. Caribbean, Atlantic and Gulf of Mexico. National Marine

Fisheries Service, Washington, D.C. 65 p.

U.S. Fish and Wildlife Service and National Marine Fisheries Service. 1993. Recovery plan for

Hawksbill turtles in the U.S. Caribbean, Atlantic Ocean, and Gulf of Mexico. National Marine

Fisheries Service, St. Petersburg, Florida. 52 p.

Witzell, W. N. 1983. Synopsis of biological data on the hawksbill turtle, Eretmochelys imbricata

(Linneaus, 1766). FAO Fisheries Synopsis No 137. 78 p.

Maurice Renaud, an ecologist, began working in Galveston, TX with the National Marine Fisheries

Service in 1980. During his tenure at NMFS, his scope of work has included topics such as shrimp

migrations, hypoxia in the Gulf of Mexico, the effect of trawling efficiency devices (TEDs) on

commercial shrimp catch, and since 1986, the behavior and migration of sea turtles, and

characterization of sea turtle habitat in the Gulf of Mexico and Atlantic Ocean. Maurice received

his B.A. in Zoology (1970) and M.S. in zoology (1971) from the University of Hawaii and his Ph.D.

in zoology (1977) from Arizona State University.
49

INDUSTRY: MAN-MADE AND NATURAL ACTIVITY IMPACTS

ON MARINE MAMMALS AND SEA TURTLES

MMS AND DEEPWATER ACTIVITIES

Mr. Jim Regg

Mr. B.J. Kruse

Minerals Management Service

Deepwater drilling activity is at an all-time high, and production from deepwater reservoirs is also

increasing. Minerals Management Service (MMS) statistics indicate that the number of rigs

concurrently operating in water depths greater than 1,000 feet has averaged 16 during late 1995 and

early 1996. In several instances the deepwater rig count has increased to levels approaching 20 rigs.

The continued growth of the deepwater Gulf of Mexico (GOM), especially the ultra-deep blocks,

might be constrained by the availability of drilling vessels capable of operating in those water

depths. Numerous trade journals have published articles about the successes of GOM deepwater

projects, lists of projects under development or pending, and water depth records for deepwater

drilling, mooring, and installations. The important point is that the GOM offshore has seen a muchneeded revitalization with the excitement of deepwater drilling and production. It is in everyone’s

best interest that the successes continue.

There are probably as many answers to the question “How deep is deepwater?” as there are

responses. From an operations perspective, the MMS considers deepwater with respect to regulating

production activities as beginning where industry uses different technology to develop and produce

oil and gas from the Outer Continental Shelf. In the Gulf of Mexico, this shift occurs where industry

stops using fixed platforms and begins using other types of facilities to produce oil and gas from

deeper waters, i.e., subsea facilities, floating production facilities, tension leg platforms, etc. The

exact water depth of deepwater is not important; however, the change in production technology

generally begins in water about 1,000 to 1,300 feet. The MMS adopted 1,000 feet as the marker for

deepwater.

Existing MMS offshore operating regulations were promulgated based on an expansion of successful

bay and inland estuary production activities. These regulations reflect mostly surface operations

where daily access to the wellhead(s) is possible. In 1988, the MMS had consolidated a multiple

layer of regulations, orders, and policies into the single document containing all then-existing

regulations. This effort resulted in updating regulatory requirements with industry operating

practices and standards and incorporating performance-oriented requirements into the regulatory

structure. Those regulations continued the focus on surface-based operations; the 1988 revision did

not address in specific terms the requirement for subsea production systems and several other

particulars associated with deepwater operations. Because of this lack of specific regulations and

different functional requirements for deepwater and subsea activities, the MMS has been granting

approvals for alternative compliance measures as departures from the existing regulations when the

alternative means provide an equal or greater level of safety when compared to the existing
50

requirements. Both the MMS and industry have concerns about the use of departures for regulating

offshore operations, especially in the dynamic deepwater arena where economic and technical

concerns can have a dramatic effect on the viability of a project. A proactive approach to addressing

the MMS and industry concerns was needed.

In response to this need, MMS formed a work group to examine regulatory issues associated with

deepwater operations and development. The primary functions of the work group were to (1) review

the current offshore operating regulations for applicability to deepwater and subsea operations and

(2) recommend measures to improve the deepwater regulatory program. This internal MMS

Deepwater Production Work Group began its regulatory analysis in early 1992 by investigating

options regarding regulations for floating and subsea production systems. One goal of the work

group was to develop a report that would address the needs of the current regulatory program with

respect to deepwater. Early in the review process, the work group prepared case studies of several

deepwater projects to obtain an accurate picture of how MMS regulates deepwater activities. The

work group examined previously raised issues regarding floating production and deepwater

activities. These issues included the approval and use of floating production systems and tension leg

platforms, deepwater pipeline design, gas flaring, extended well testing, and subsea production and

safety system requirements.

A review of deepwater projects revealed that MMS had no major problems in the review and

approval of past deepwater projects. However, the case studies revealed that MMS had to grant

departures to the regulations in the approval of each project. The case studies also indicated that the

review process by MMS was not always consistent. The MMS granted some departures because the

technology used did not fall within the parameters of the current regulatory requirements. For

example, industry was not able to monitor the annulus pressures in all casing strings in sub sea wells

because of the design of subsea wellheads. The MMS granted other departures for underwater and

subsurface safety valves because the current regulations do not adequately address this equipment

when it is used in deepwater and subsea operations.

A primary example of MMS and industry proactive cooperation is the new approach for reviewing

deepwater development activities, referred to as the Deepwater Operations Plan. Through the

DeepStar Regulatory Issues Committee, MMS and industry participants were able to jointly evolve

the Deepwater Operations Plan concept for subsea development. DeepStar took the lead to develop

a working model of the plan using a known and previously approved GOM subsea development

project as a guide. Periodic meetings of the Regulatory Issues Committee provided the opportunity

for industry and MMS feedback as milestones were achieved in the working model development.

The Deepwater Operations Plan evolved, formal comments were solicited and alternative versions

of the guidelines were considered. The cooperation and open dialogue from both the industry and

MMS were key to the formulation of guidelines to be used for subsea deepwater operations plans.

The MMS has adopted these guidelines and announced the implementation of the Deepwater

Operations Plan requirement by a Letter to Lessees and Operators. Before finalizing the guidelines,

the Gulf of Mexico Offshore Operators Committee, Independent Petroleum Association of America,

and DeepStar member companies were provided a final opportunity to comment on the document

and implementing Letter to Lessees and Operators.
51

The guidelines for implementing the Deepwater Operations Plan identify specific needs concerning

the areas noted above. An important point to recognize is that the plan is not intended to duplicate

other submittals required by the MMS; anything that has received prior approval or that is pending

can simply be cross referenced in the Plan.

The MMS and industry benefit from the Deepwater Operations Plan through the early interaction

and dialogue regarding the proposed development strategy. The plan is submitted to the MMS in

three parts: conceptual, preliminary, and final. Each part reflects the operator’s state of knowledge

regarding the project and provides an early opportunity for the operator and MMS to agree on the

proposed development strategy (design basis and philosophy) prior to major expenditures. The

conceptual part addresses innovative and unusual technologies essential for the viability of the

project. The preliminary part identifies the alternative compliance measures to be used along with

the description of the overall system configuration. Updates to the previous submittals are the main

focus for the final part. This three-part submittal approach for a Deepwater Operation Plan is

intended to reduce the overall risk of the project.

The MMS and DeepStar have cooperated since 1992 to facilitate the development of deepwater

discoveries in an environmentally and safety-conscious manner. The purpose of this cooperative

effort has been to move both industry and regulators toward a common goal of mitigating all barriers

to deepwater development. The approach has been to identify issues and concerns to be fully

discussed before actions are formulated. Through the interaction and substantial contributions from

industry through DeepStar, MMS has been able to adopt a total-systems approach to reviewing

deepwater development activities. This new approach, referred to as the Deepwater Operations Plan,

provides for using alternative compliance measures where justified, rather than obtaining departures

from regulations and policies based on fixed-leg platform type operations. The approach also avoids,

at least in the near term, the development of safety regulations that would require frequent revisions

because of evolutionary deepwater technology. The Deepwater Operations Plan approach provides

an early regulatory review prior to full-scale development, a measure that should reduce some of

the risk associated with deepwater development planning.

The approach adopted by MMS and DeepStar has potential application in other areas as well. The

co-sponsoring of informational workshops and scoping initiatives, safety and technology research,

and the early involvement in regulatory initiatives will benefit both industry and the MMS.

Jim Regg is Chief of the Technical Assessment and Operations Support Section with the MMS Gulf

of Mexico Region, located in New Orleans. His office is responsible for technical, safety, research

and regulatory issues relating to drilling and production activities in the GOM Outer Continental

Shelf. Jim has offshore experience in drilling and production operations in Alaska and the Gulf of

Mexico, and also experience with the MMS offshore inspection program. He has had numerous

papers published, conducted several workshops, and serves on several joint MMS-industry

initiatives, including DeepStar. Jim received a degree in petroleum engineering from Pennsylvania

State University in 1983.
52

B.J. Kruse is a registered Professional Petroleum Engineer in Louisiana with 25 years of oil industry

and government experience. He received his B.S. in petroleum engineering from LSU in 1974 and

his M.A. in economics with a minor in finance from the University of New Orleans in 1987. He has

experience as an operations engineer, reservoir engineer and production engineer with major oil

corporations such as Union Oil Company of California, Gulf Oil Corporation and Chevron U.S.A.,

Inc. He has spent the last six years with the Minerals Management Service as a staff petroleum

engineer dealing with the MMS Supplemental Bonding Program and liability issues associated with

offshore platforms in the Outer Continental Shelf of the Gulf of Mexico.
53

OFFSHORE PRODUCTION OPERATIONS:

AN OVERVIEW OF GULF OF MEXICO OCS OIL AND GAS OPERATIONS

Ms. Sandra M. Fury

Chevron U.S.A. Production Company

Domestic U.S. offshore oil and gas industries operate with the permission of the public and under

the regulatory supervision of a number of state and/or federal agencies. In general, the U.S. Minerals

Management Service oversees leasing, royalty payments, exploration and production planning,

facilities, operations, pipelines, abandonment, environmental impact mitigation, and coordination

with other agencies. EPA regulates discharges into Gulf of Mexico waters and, in the eastern Gulf,

air emissions. The Coast Guard governs life-saving systems, emergency evacuation plans, fire

fighting systems, and oil spill responses. NOAA, NMFS, DOE’s RSPA and the Army Corps of

Engineers oversee various other OCS activities. In all, OCS oil and gas activities are among the most

tightly regulated in the world. The remainder of this paper describes what kinds of facilities and

operations those are.

The earliest OCS facilities, dating back to the 1930’s, were relatively simple structures framed of

timbers. Within a decade, however, steel structures began displacing wooden ones and allowing the

industry to work in deeper waters. Today, approximately fifty years after OCS exploration and

production began, water depths approaching 10,000 ft. are being explored. 

With this extension into deeper waters have come new technologies for drilling and producing new

discoveries. A new generation of drilling ships, for example, is under construction. Wells are being

completed on the seabed and piped back to existing infrastructure for processing. Various kinds of

floating and tension-moored structures are producing in waters so deep that they render conventional

pile-supported structures impractical. Among the most innovative of these structures is Chevron’s

Genesis spar – a huge, floating buoy-like hull supporting multiple decks of production equipment

and marine systems. Genesis is unique in its capability to simultaneously produce oil and gas while

drilling new wells (or “working over” existing wells). It operates in 2,600 ft. of water in Green

Canyon Block 205, about one hundred miles south of Grand Isle, Louisiana.

Another technological development has been the industry’s ability to complete wells at the seabed,

eliminating the need for surface structures entirely. In this kind of development, all of the controls

needed to operate the wells are placed on the seabed and operated remotely via an umbilical bundle.

Oil and gas flows through a blowout preventer atop each well to a nearby production manifold.

There, the production is combined and exported to a conventional production facility via subsea

pipeline. An example of this development is the Gemini production system in Mississippi Canyon.

Texaco operates the subsea system, located in 3,745 feet of water. Production from Gemini is tied

back to partner Chevron’s facility in Viosca Knoll Block 900 for processing and transport to shore.

Most of the “major” structures, or platforms, on the OCS house various numbers of wells and the

production equipment used to separate oil, water and gas; generate power; pump oil and gas to

shore; and provide living quarters for the crews. In older, shallower fields there are often a number
54

of smaller satellite structures which may be as simple as a caisson for a single well and a small

“flowline” to transport its production back to a processing platform. Of course there is also a

continuum of structures intermediate in size between “major” and single well structures. Typically,

these intermediate facilities house multiple wells and various combinations of processing and

separation equipment.

The central and western OCS in the Gulf of Mexico is home to thousands of oil and gas production

structures. During the operational lives of these facilities, submerged structural members become

thickly encrusted with algae, sponges, corals and other organisms. In a very real sense they become

artificial reefs. Those communities in turn attract free swimming grazers and predators, including

many species more typical of natural coraline reefs of lower latitudes than of the soft, sedimentary

basin which characterizes most of the Gulf of Mexico. 

The topsides of these facilities also serve as an archipelago of rest stops for birds and insects

migrating between North and Central America via the Gulf. Sea turtles, whales, dolphins and

porpoises are frequently found in the vicinities of platforms, though they probably do not utilize

them for feeding or shelter. 

After OCS facilities become surplus they must be removed in accordance with U.S. and international

law. In recognition of the fisheries habitat they provide, however, most of the Gulf states encourage

operators to donate surplus structures to permitted artificial reef sites. These states’ artificial reefs

programs assure continued benefits to fisheries otherwise limited by absence of naturally-occurring

“hard-bottom” reef substrate.
55

12,000+

( >7.5 miles)

 m offsets

1500+ m spreads

( ~ 1 mile)

> 120 total km of streamers

can be towed by 1 vessel

Figure 6. The seismic industry will continue to increase the amount of in-sea equipment for the

acquisition of 3D seismic surveys.

ACOUSTIC ACTIVITIES OF THE SEISMIC INDUSTRY

Dr. Jack Caldwell

Core Laboratories, Houston

INTRODUCTION

This paper provides a brief overview of some of the continued improvements and recent advances

in the acquisition and use of 3D seismic data. Length constrains the topics to be covered in this talk

to (1) a brief review of the seismic equipment used in 3D seismic surveys today, and the recognition

that more and more in-sea equipment is being towed behind purpose-built and purpose-modified

seismic vessels, (2) some technical tidbits about airgun arrays, and (3) recent developments in

seismic seabed equipment used in repeat 3D seismic surveys (popularly known as 4D seismic), and

in marine multicomponent seismology (marine 4C).

EQUIPMENT LAYOUT IN 3D SEISMIC SURVEYS TODAY

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 6). Spreads of up to 1,500 meters (the total separation
56

Figure 7. A streamer cable rolled up on a drum.

from the leftmost streamer to the rightmost streamer) and more, and streamer lengths of up to 12 km

will be seen in 1999. Some contractors can achieve these maximum geometries with a single vessel;

others will need as many as three or four vessels to attain this geometry. The sea area covered by

the length of the streamers multiplied by the spread of the full set of streamers defines the

acquisition footprint. The acquisition footprint, on average, associated with a single traverse of a

seismic vessel will increase in area over the next couple of years, and open water tracts (such as the

deepwater in the Gulf of Mexico) provide areas where operations using these maximum geometries

are most cost-effective.

Figure 7 shows a streamer cable rolled up on a drum, or reel, where the reel has a diameter of about

12 feet. The diameter of the streamer is slightly larger than 2 inches. The yellow cylinders seen

inside the streamers are spacers that maintain the streamer’s shape and keep the internal electrical

wires and sensor units in their correct positions.

Figure 8 illustrates how a seismic survey is actually shot. If the desired geometry of the ship’s tracks

is indicated on the left side of the diagram, then the vessel towing its airguns and streamers will

actually shoot the area Zamboni-style, as indicated on the right half of the diagram. It must be kept

in mind that the colored arrows in the right half of the diagram denote a total system geometry of

a vessel, its airgun array(s), and the long line(s) of streamers being towed behind it.

Towing longer streamers, more streamers, and a wider spread of streamers means that today’s

seismic vessels have to be more powerful than those of yesterday, which typically means more

powerful engines and larger and/or more powerful propellers (screws). It might be thought that these

more powerful systems would be noisier than the older ones, but R&D efforts have ensured, in fact,

that today’s systems are as quiet, if not quieter than earlier models. Therefore, the ultimate effects

of increasing the size of the acquisition footprint are to (1) reduce the number of firings of an airgun

array for a given 3D seismic survey, and (2) reduce the time it takes to shoot a given survey.
57

Figure 8. An illustration of how a seismic survey is shot.

TECHNICAL TIDBITS ABOUT AIRGUNS

Figure 9 shows a portion of an airgun array. Note the man kneeling for scale. Notice the floats that

support the airguns (the orange tubes that look like large hot dogs) and the air guns themselves

hanging beneath the floats. Typical volumes of air expelled by airguns vary from about 30 cubic

inches up to about 800 cubic inches, and when one speaks of the volume of an airgun, or about the

size of an airgun array, it is in terms of this volume (for a single gun), or the sum of the volumes of

each gun (for the whole array). Total airgun array sizes cover a wide spectrum, but most of the

industry’s arrays will be between 3,000 and 8,000 cubic inches. An airgun array generally consists

of three to six subarrays, with each subarray being a linear alignment of four to eight individual

airguns. This means that each complete airgun array will typically involve 15 to 30 individual guns.

Most of the seismic industry use airgun arrays whose operating pressure is 2,000 pounds per square

inch. 

Figure 10 shows a schematic diagram of a specific airgun array, one that is 3,959 cubic inches in

total volume, has 3 subarrays (each line of ovals), uses 17 airguns (each individual oval represents

an airgun, and the nearest number represents the volume of that gun in cubic inches), and measures

18 meters by 18.5 meters in size. The location of the airgun array is indicated in Figure 10 in the

inset aerial photo of a seismic vessel. A key concept to note here is that an airgun array is definitely

not a point source, but one that spans a small area. The specific design of an airgun array is based
58

Note M an

Kneeling

Figure 9. A portion of an airgun array. Note the man kneeling for scale.

on the desire to have a source that emits a very symmetric packet of energy in a very short amount

of time, and with a frequency content that penetrates well into the earth in the particular geographic

location in which the seismic work is being conducted. Those desires then dictate how many guns

of what size form the total array, and dictate the exact location and firing pattern of the individual

airguns. The firing times of the individual guns are staggered by milliseconds so as to make the farfield pulse emitted by the total array as coherent as possible. The choreographing of the firing times,

and the ensuring of its proper execution, is known as tuning the airgun array.

The sound pressure (amplitude) generated by an airgun array is 

(1) linearly proportional to the number of guns in the array: all else being equal, a 30-gun array

will generate twice the amplitude of a 15-gun array; 

(2) linearly proportional to the firing pressure of the array: typically the industry uses 2,000 psi,

but a 4,000-psi-array will have twice the amplitude of a 2,000-psi-array; 

(3) proportional to the cube root of the volume of the array: an 8,000-cubic-inch-array will

generate twice the amplitude of a 1,000-cubic-inch-array. 
59

18

18.5

340 195 155 125 90

660 415 280 195 145 105

500 290 195 125 90 54

Figure 10. A schematic diagram of a specific airgun array, one that is 3,959 cubic inches in total

volume, has 3 subarrays (each line of ovals), uses 17 airguns (each individual oval

represents an airgun, and the nearest number represents the volume of that gun in cubic

inches), and measures 18 meters by 18.5 meters in size. 

The sound pressure level decreases rapidly as the distance from the source increases. At distances

of about 500 meters and more (also known as the far-field), the individual airguns in airgun arrays

will look as if they are all working as one source; they constructively interfere with one another, and

the total array can then be considered a “point source.” For distances less than that, and particularly

within about four or five array dimensions, 125 meters or so (known as the near-field), the effect of

numerous guns firing asynchronously is to cause destructive interference of the output of each

individual gun. 

If an airgun array were a point source, then one could make measurements a few hundred meters

away from it, and mathematically back-calculate the level of the generated sound pressure at the

exact location of that point source. For typical industry airgun arrays, that typical back-calculated
60

0

2

4

6

8

Bars

Cubic Inches ofEach Airgun

54 

465 155 

235 

90 

30 

90 

585

195 

290 

125 

54 

54 

465 155 

235 

90 30 

54 

465 155 

235 

90 30 

90 

585

195 

290

125 

54 

54 

465 

155 

235 

90 30 

Actual Maximum Output of Airguns

(372 Firings of Each Airgun)

Array 1 Array 2

Figure 11. Data recorded by hydrophones for dual 3,397-cubic-inch arrays. Each of the two arrays

consists of 24 guns, eight in each of three subarrays. Each array is 20 meters wide by 15

meters long. These data are from a survey acquired in May 1999.

value would b e on the order of 100 bars. Numbers of that magnitude are what the seismic industry

publish to let its clients know the effective output at great distances of its array. Because the arrays

used are not point sources, the mathematical back-calculations are not accurate at all in terms of the

sound pressure actually encountered within 125 meters or so of the center of an array. Actual

measured values verify that the maximum real sound pressure experienced anywhere within the

near-field is less than 10 bars, or less than one-tenth the published values. 

In typical industry practice, a hydrophone is placed one meter away from each airgun in an array,

and it is used to measure the actual sound pressure generated at that point. (The industry uses these

hydrophone data to monitor the performance of each airgun and to help in the computer processing

of the data.) Figure 11 shows data recorded by these hydrophones for dual 3,397-cubic-inch arrays.

Each of the two arrays consists of 24 guns, eight in each of three subarrays. Each array is 20 meters

wide by 15 meters long. These data are from a survey acquired in May 1999.
61

Each bar in this graph represents the average maximum pressure (zero-to-peak) measured by each

gun hydrophone (located 1 meter from the gun) for 372 firings of each gun. The number along the

bottom of the plot indicates each gun size. Data from the first array is shown on the left half of the

graph starting with the first “465” and ending with the second “30” annotation. Data from the second

array is shown on the right half of the plot, beginning with the third “465” and continuing to the

right. The maximum average value is 7.19 bars, and is generated by the 290 cubic-inch gun in the

first array. The absolute maximum in this total data set, not discernable from this plot, but observed

in the raw data before averaging, is 8.73 bars. Several observations:

(1) the two arrays look very similar in their outputs;

(2) the most energetic guns are not the largest guns;

(3) different guns of the same size have very similar outputs;

(4) the maximum output actually measured anywhere is less than 10 bar-meters.

In the actual recording of seismic data, the sound pressure of the first energy being recorded by the

sensors in the streamers will typically be in the 40 to 60 millibar range. This is due to the relatively

long distance traveled by the energy before reaching the nearest sensors (a few hundred meters typically). In good conditions, the ambient noise level, made up of in-streamer noise such as vibrations

and bulge waves, as well as environmental noise like wind and waves, will be around 2-3 microbars.

Figure 12 shows the amplitude level for a typical seismic trace as a function of recording time (the

heavy line). The amplitude decay for cylindrical spreading of a pressure pulse is indicated on this

plot, and the decrease is proportional to one over the square root of the distance from the source. The

amplitude decay for spherical spreading of a pressure pulse is also indicated on this graph, and the

decay is proportional to one over the distance from the source. The plot indicates that most seismic

traces will decay somewhere between the spherical spreading case and the cylindrical spreading

case. (Exactly how the sound decays depends on the specifics of the survey area.) Also shown on

this plot are various reference points:

(1) the back-calculated level of airgun arrays (the 260 dB ref 1 microPascal at 1 meter),

(2) the actual maximum level of airgun array output (the 220-230 dB level) corresponding to

5-10 bar meters (zero-to-peak) and 3-7 bar meters (RMS),

(3) the current level of caution indicated by mammal experts (180 dB), and

(4) the level of the click of a solenoid that initiates the firing of an airgun (160 dB).

MARINE MULTICOMPONENT (4C) SEISMOLOGY

The four-component (4C) seismic is another application that makes use of either sensor-filled cables

or individual sensor packages placed in direct contact with the seafloor. The four components are

a hydrophone (denoted by P in Figure 13), a vertical geophone (Z), and two horizontal geophones

(X and Y) oriented perpendicular to each other. All four are included at each receiver station

location. The cartoon in Figure 13 shows schematically how marine 4C seismic data are acquired

using a cable system, which is laid on the seafloor. Generally, two vessels are used: one a source

vessel, and the other a cable deployment and recording vessel. 
62

Figure 12. The amplitude level for a typical seismic trace as a function of recording time (the

heavy line).

The seabed sensor systems routinely deliver data of higher quality than conventional towed-streamer

data. There are several reasons for this difference: 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). But fact that these cables deliver better data than towed streamers is not the only

reason for going to the hardship and expense of deploying such seabed systems. Even more

important is the ability of these systems to record a type of wave not recordable by streamers, and

this is the shear (S-) 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).

When an S-wave passes through a rock, however, 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 Pwaves, and that they can not exist in fluids (hence the necessity of placing the recording sensors on

the seafloor). 
63

ZX Y P

Figure 13. The cartoon shows schematically how marine 4- component seismic data are acquired

using a cable system, which is laid on the seafloor. Generally, two vessels are used, one

a source vessel and the other a cable deployment and recording vessel.

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. 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 that apply equally well in both the

onshore and offshore environments:

• Improved lithology (mineralogy) prediction

• Improved pore fluid prediction

• Better S/N in areas of low P-wave impedance contrast or high P-wave attenuation

• Calibration for AVO (amplitude versus offset) studies

• Azimuthal anisotropy (the variation of seismic properties with horizontal direction)

• Another parameter for seismic reservoir monitoring (4D seismic).
64

Courtesy ofStatoil

P - P

P - S

Figure 14. An example of imaging beneath gas using S-wave energy.

Other applications, listed below, 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

• Deepwater multiple removal

• Cost-effectiveness (compared to the cost of offshore wells).

Figure 14 is an example of imaging beneath gas using S-wave energy. This example, presented in

1994 (Berg, E., Svenning, B., and Martin, J., 1994, “SUMIC - A New Strategic Tool for Exploration

and Reservoir Mapping,” 56th Annual EAEG Meeting, Vienna), kick-started the interest in marine

multicomponent. 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 application of 4C seismic has been successful in more
65

Figure 15. The basic concept of seismic time-lapse monitoring.

than 20 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.

SEISMIC TIME-LAPSE MONITORING (STLM) OR 4D SEISMIC

Figure 15 depicts the basic concept of seismic time-lapse monitoring. An initial seismic survey is

shot over a field and delineates the reservoir before any production occurs. The data are analyzed,

and wells are drilled. After some period of production, another seismic survey is run, those data are

interpreted and compared to the previous seismic data. Decisions are made as to where new wells

need to be drilled. Those wells are drilled, and production continues. After some time, another

seismic survey is acquired, and the sequence of events repeats.

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 of fluids when used in conjunction with all other data available

(well log, geologic, core, production, etc.). 
66

Figure 16. A real-world, North Sea field example where seismic attributes were used to map the

fluid distribution in a reservoir under production.

Figure 16 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 major question the industry has

with respect to STLM. The following list of statements sums 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

While these statements are self-explanatory, the fourth one requires some clarification: 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 major factors that may affect

repeatability, outside of the reservoir changes themselves that 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:
67

• 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 that are 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 the surveys 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 action/currents 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 and/or more

complete seismic data, the industry is beginning to use cables 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.

Figure 17 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 inline with the streamer receivers).

SUMMARY

This paper has attempted to provide a brief overview of some of the continued improvements and

recent advances being made in the marine seismic industry, as well as to provide a short summary

of airgun array practices and technology. A constant stream of new developments has been ongoing

for some time, and it does not look to abate in the near future. Conventional towed streamer 3D

surveys will continue to be done more efficiently and to deliver higher data quality than past

methods have produced. Time-lapse seismic monitoring and 4C seismic will become important

technologies delivered by the seismic contractors for improved reservoir characterization and

management. A primary goal of this paper has been to disseminate information about how the

seismic industry conducts its data gathering. This is done in the hope that it will foster better
68

Figure 17. A depiction of an array of vertical cables, and the trenching of a cable into the seafloor.

cooperation and communication among the various groups interested in the well-being of our oceans

and its inhabitants.

Jack Caldwell is a vice-president at Core Laboratories in Houston, Texas. He has worked for

Schlumberger as a manager of Reservoir Solutions responsible for reservoir characterization and

monitoring activities using seismic techniques for the North and South American Region. He has

a B.S. degree in math and a Ph.D. in geophysics. Dr. Caldwell has over 20 years of experience—10

years with Texaco and Marathon, another 10 years with Schlumberger, and presently Core

Laboratories.
69

BIOLOGICAL IMPACTS OF UNDERWATER EXPLOSIVES USED

IN PLATFORM SALVAGE IN THE GULF OF MEXICO

Mr. Gregg Gitschlag

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Southeast Fisheries Center

Galveston, Texas

BACKGROUND

During a one-month time span in the spring of 1986, 51 dead sea turtles and 41 dead dolphins

washed ashore near Galveston, Texas. During the first two weeks of this period, a series of at least

22 explosions occurred in conjunction with oilfield structure removals a few miles offshore. This

raised serious concern over the potential impact of these activities on endangered and protected

species of sea turtles and marine mammals since there are roughly 4,000 oil and gas structures in

the Gulf of Mexico and all of them must be removed eventually. As a result, under the auspices of

the Endangered Species Act an Incidental Take Statement (Table 5) was prepared which listed

requirements aimed at protecting sea turtles. Beginning in 1987, an observer program was

established to monitor every structure removal in the U.S. Gulf of Mexico where more than 5 lb or

2.3 kilos of explosives were used. From 1987-1999 a total of 1,175 structures (average of 90 per

year) were monitored by National Marine Fisheries Service personnel. 

Table 5. Summary of Incidental Take Statement for Sea Turtles.

1. Qualified observers monitor for sea turtles beginning 48 hours prior to detonations.

2. 30 minute aerial surveys within one hour prior to and after detonation.

3. If sea turtles are observed within 914 m of the structure, detonations will be delayed until

attempts are successful in removing them at least 914 m and the aerial survey must be repeated.

4. No detonations will occur at night.

5. During salvage-related diving, divers must report sea turtle and marine mammal sightings. If

sea turtles are thought to be resident, pre- and post-detonation diver surveys must be conducted.

6. Detonation of explosive charges must be staggered to minimize cumulative effects of the

explosions.

7. Avoid use of “scare” charges to frighten away sea turtles which may actually be attracted to

feed on dead marine life and subsequently exposed to explosions.

8. Removal company must file a report summarizing the results.
70

In addition to sea turtles, observers also watched for marine mammals. In November 1995 an official

authorization for marine mammals was finalized. For companies requesting an authorized take of

marine mammals, requirements are the same as for sea turtles, plus the following:

1. No waivers can be given for aerial surveys (aerial survey’s are sometimes waived if bad

weather precludes flying).

2. In addition to the aerial survey, which must be performed within an hour after each blasting

event, either an ROV or diver survey must be conducted within 24 hours or an aerial or

vessel survey must be conducted within 2-7 days.

RESULTS

The following are some of the highlights of the Platform Removal Sea Turtle Observer Program.

Monitoring effort was partitioned by surveys conducted from vessels and platforms at the sea

surface during the day and at night and from aerial surveys that were only performed during daylight

hours. Most monitoring occurred during the day, somewhat less monitoring at night, and a very

small amount during aerial surveys. Results were standardized by dividing the number of individual

turtles observed by the number of monitoring hours for each survey method to yield the turtle

observation rate. From 1986-94 day and night sea turtle observation rates from surface surveys were

about the same, but the aerial survey rate was 10 times higher. For the 1986-98 period this value was

17 times higher, which attests to the great superiority of aerial surveys over surface surveys in

detecting the presence of sea turtles.

From 1986-1998, 576 lease blocks were monitored. Lease blocks typically measure about 2 nautical

miles or 4 km on a side. National Marine Fisheries Service personnel observed 127 individual sea

turtles at 22% of monitored blocks. Most turtles that occur at offshore removal sites are loggerheads,

although all of the five species that occur in the western Gulf of Mexico have been observed. One

turtle was reported killed in 1986 during opportunistic monitoring and prior to the official beginning

of the observer program in 1987. Since 1987 one additional loggerhead turtle was killed by

explosives and two more were injured, rehabilitated and released back into the Gulf of Mexico. Nine

turtles were captured during the program. Seven of these captures occurred prior to detonation of

explosives, indicating that these animals were saved from potentially lethal blast impacts.

From 1986-1994 nearly 19,000 sightings of marine mammals including bottlenose and spotted

dolphin were recorded. Because many of the observations may have been resightings, this value

should not be taken as a population estimate. Of the 576 lease blocks monitored, 483 or 84% had

dolphins. No killed or injured dolphins were observed and none were captured during the program.

PROTECTING “PROTECTED SPECIES” FROM DETONATIONS

Current Practices

When dolphins and sea turtles are encountered at explosive structure removal sites, there is little in

our arsenal of techniques to coax them out of the designated 1,000 m impact zone. When dolphins

are present, attempts are made to move them out of the area using a vessel in the hope that they will

ride the bow or stern waves. If this is unsuccessful then a very small explosive charge (6 ft of
71

detonation cord) is detonated in an attempt to scare the animals from the area. These procedures are

“hit or miss” and many times all that can be done is to delay the detonation of structure-severing

explosives until the animals move off of their own volition. When sea turtles are observed, then

diver surveys are made to attempt capture of the animal prior to detonations. While capture rarely

occurs, the presence of a diver in some cases may at least disturb the turtle and set it in motion from

beneath the platform.

Information Needs

A high degree of protection can be afforded protected species if explosive structure removals can

be scheduled at times and places when these species are not present. Although this may not always

be possible due to industry needs, knowing where and when protected species occur is essential

information for this process. A few “hot spots” of sea turtle activity are known. For example,

Kemp’s ridley sea turtles occur in relatively large numbers near Sabine Pass, Texas in spring and

loggerheads nest on the Chandeleur Islands in spring and summer.

Technology

A technological “fix” to protect sea turtles and marine mammals from explosive impacts has not

occurred. Recent research into the development of charge designs that release less energy into the

water column have the potential to significantly reduce the size of the impact zone. Pressure

dampening devices such as mats or bubble curtains have also been mentioned in this regard but are

not being used for several reasons. The degree to which bubble curtains and mats would reduce the

impact distance has not been researched and may or may not be theoretically effective, cost

effective, or logistically feasible. The use of acoustic signals, food, etc. to attract or repel sea turtles

and dolphins from the impact zone has not been thoroughly researched and presents complex

logistical issues. However, experimental testing of specific stimuli, such as killer whale sounds to

repel dolphins, may be cost effective and warrant research.

CONCLUSIONS

Impacts of underwater explosives on sea turtles and marine mammals appear to be small in

comparison to other sources of mortality when requirements of the Incidental Take Statement are

met. However, impact assessment is limited primarily to dead and seriously injured animals that

appear at the surface shortly after explosives are detonated. Sublethal impacts that do not result in

immediate abnormal behavior at the sea surface are not really assessed well with current monitoring

protocols. Although not a panacea, use of acoustical signals (such as testing effects of killer whale

sounds on dolphin movements) to move sea turtles and marine mammals from the impact zone

immediately before detonations may warrant research.
72

Figure 18. Flight IIA guided missile destroyer (DDG), Winston S. Churchill.

NAVY EXPLOSIVES TESTING

Mr. William Sloger

Department of the Navy

The DDG 81 Shock Trial is the latest in a series of shock trials done for each new class of Navy

ships (Figure 18). The DDG 81 represents a major upgrade to the DDG 51 Arleigh Burke class,

which will represent the major force in the surface Navy by 2010. 

The shock trial is in a number of ways very similar to the last shock trial the Navy planned, for the

SeaWolf submarine, which is scheduled for next summer but will not likely occur. These shock

trials, which are required by law (10 USC 2366), are intended to test a ship’s survivability and

combat readiness in an underwater explosion environment and to lead to improvements where

needed. The DDG 81 shock trial will consist of the detonation of three 10,000-pound charges at the

rate of one per week. Each succeeding detonation will place the charge progressively closer to the
73

Operations Vessel Wind Direction

Array

Tension

Line

2000'

Varies

Charge Float

(Charge 200' Below Surface)

DDG 81

Figure 19. Explosive shock trail components.

ship to increase the intensity of the shock wave propagated through the ship’s hull. The shock trial

is planned to occur between 1 May and 30 September 2001 (Figure 19).

Putting together the Draft EIS for this shock trial, we plan to complete the NEPA process with a

Record of Decision in the spring of 2001. The EIS is also being produced in accordance with

Executive Order 12114, which applies to Federal actions in the global commons. The requirements

of the Endangered Species Act (ESA), Marine Mammal Protection Act (MMPA), Coastal Zone

Management Act (CZMA), and Magnuson-Stevens Act will also be met. The Navy is also working

very closely with National Marine Fisheries Service (NMFS), which has agreed to act as a

cooperating agency in development of the EIS.

We went through two preliminary phases before beginning the NEPA process. The first was an

operational evaluation of the test and what locations could actually support it. We began by looking

at all Navy bases on the West, Gulf, and East coasts, a total of 16 bases. After evaluating these bases

against a fairly lengthy list of operational criteria, we narrowed the field to three areas: Norfolk,

Mayport, and Pascagoula (Figure 20). Some of the criteria included: Navy personnel tempo

requirements, proximity to a naval base with certain assets (support ships, planes, repair facilities),
74

POTENTIAL POTENTIAL

TEST

 AREAS

VA

NC

SC

MS AL GA

FL

Gulf of Mexico

Atlantic

Ocean

NAVAL STATION

NORFOLK

NAVAL STATION

MAYPORT

NAVAL STATION

PASCAGOULA

NORFOLK

MAYPORT

PASCAGOULA

Figure 20. Potential test areas.

ship traffic, and weather. All three of these areas were considered operationally equal, so the final

selection of a single area will be based on environmental factors. 

The next phase was a review of the literature for the three sites. The purpose of this phase was to

describe environmental conditions in each area and develop maps of environmental constraints. It

would also provide a basis for the affected environment section of the EIS. The review of the

literature showed that the potential for presence of marine mammals and turtles is somewhat similar

at the three areas (Table 6). At Norfolk, up to 35 marine mammal species may be present, including

7 mysticetes, 27 odontocetes, and 1 pinniped. For all of these totals, both listed and non-listed

species are included, as well as those that are unlikely to be present based on low frequency of

sightings. At Mayport, up to 29 marine mammal species may be present, including 7 mysticetes and

22 odontocetes. At Pascagoula, up to 29 marine mammal species may be present, including 7

mysticetes, 21 odontocetes, and 1 exotic pinniped (California Sea Lion). Five species of sea turtles

may occur at any of the three test areas. We do know, however, that Norfolk will likely be the first

area to drop from further consideration due to the results of past surveys which indicate higher

densities of mammals.
75

Table 6. Calculated Critical TTS Distances (Nautical Miles).

Norfolk

Depth(ft) Mysticetes Odontocetes

600 15.0 9.0

6,000 23.0 17.0

7,700 21.0 17.7

Mayport

Depth Mysticetes Odontocetes

600 13.0 8.0

1,200 13.0 11.0

2,300 15.0 13.6

Pascagoula

Depth Mysticetes Odontocetes

600 12.3 8.6

1,200 16.0 10.0

2,200 14.4 13.3

Two criteria basically define the bounds of the areas we are looking at: a minimum water depth of

600 feet and a maximum distance from shore of 100 nautical miles. Within these areas we encounter

water depths up to 8,400 feet at Norfolk, 2,800 feet at Mayport, and 2,300 feet at Pascagoula. The

total square mileage within the three candidate areas ranges from 1,600 nmi2 at Pascagoula to 2,300

nmi2 at Mayport. Other features that likely will influence the candidate test areas include the Gulf

Stream at Mayport and the Loop Current at Pascagoula.

Presence of marine mammals and turtles in the candidate areas is the Navy’s greatest concern. For

that reason, we are going through a series of very conservative steps to ensure that the final test site

within a given test area will have a very low likelihood of having mammals or turtles present. In the

Draft EIS, we will name a preferred test area, which will be chosen based on its having the lowest

estimated marine mammal and turtle densities. We will generate those estimates from data received

from several sources. For Norfolk, we will use data primarily from a series of cruises done by the

NMFS Northeast Science Center during the 1990s. These include cruises by the Chapman, the

Delaware, the Pelican, and the Abel-J. For Mayport, we will be flying aerial surveys twice this

summer. And for Pascagoula, we will use aerial survey data from GulfCet II. The next in this series

of steps will be to fly aerial surveys of the test area in the week before the first detonation. Based

on the results of these flights, a primary test site as well as two back-up sites will be chosen from

within the particular area. On the day of each detonation a very extensive monitoring and mitigation

program will be in effect. It will include aerial observers, shipboard observers, and an acoustic

monitoring system. The monitoring program is designed to ensure the test area is free of marine

mammals and turtles at the time of detonation (Figures 21, 22, 23).
76

Figure 21. Exclusionary map of the Mayport test area.
77

Figure 22. Exclusionary map of the Norfolk test area.
Figure 23. Exclusionary map of the Pascagoula test area.
79

Because this test may affect marine mammals and turtles, the Navy will submit an application to

NMFS for an incidental take permit. We will calculate the regions of influence from the detonations

much as they were calculated for the SeaWolf shock trial several years ago. Mortality is defined by

onset of extensive lung injury in a calf dolphin. This results in a range of under one mile. The injury

range is defined by 50% TM rupture. As with mortality, it is assumed that 100% of the animals

within this range would be affected. This range is a little over one mile. These are the areas of

greatest concern to us. The efforts previously mentioned regarding test day monitoring will focus

on an area that will be approximately double the injury range.

The other effect the shock trial may have on marine mammals and turtles is auditory threshold shift.

We have quantified the impact of harassment, as was previously done for the SeaWolf program,

through the use of temporary threshold shift (TTS). The TTS criteria will be used to develop

estimates of acoustic impact ranges for marine mammals and turtles, to estimate extent of

harassment. We will use two criterion to define a given position in the water column at which TTS

would not be expected to occur: (1) whether the peak pressure is less than 12 psi, and (2) whether

the energy density in all 1/3 octave bands is less than 182 dB re 1mPa2

 m sec. Different frequency

ranges will be used for odontocetes and mysticetes due to differences in low frequency hearing

sensitivity. For odontocetes we will look at frequencies > 100 Hz, and for mysticetes frequencies

> 10 Hz.

The pressure-time waveforms were calculated using the REFMS computer model for shock wave

transmission. This model includes the effects of multiple surface and bottom reflections of the shock

wave as well as refractive effects. The results vary from site to site partly due to the sound speed

profile of the water at a site and partly due to water depth.

Following the schedule we are currently on, we plan to have the Draft EIS out to the public at the

beginning of December of 1999.

William R. Sloger, P.E., is an environmental planner in the Land Management Division of Naval

Facilities Engineering Command, Southern Division, located in Charleston, South Carolina. He

works as the project manager of numerous environmental impact statements and environmental

assessments dealing with marine-related activities of the Navy.
80

HUMAN ACTIVITIES AND NATURAL EVENTS: IMPACTS ON

GULF OF MEXICO MARINE MAMMALS, PART 1

Dr. Bernd Würsig

Texas A&M University

The Gulf of Mexico ecosystem is enormously diverse and ever-changing. Up north and near shore,

cold winters can bring slush ice to its channels and bayous; down south, true tropical conditions

reign. And in deep waters, the warm Yucatan Current invades from the Caribbean Sea, buds off

gyres and eddies as it flows into the northern Gulf, loops towards the east through the Florida Straits,

and joins the Gulf Stream. Warm core anticyclonic eddies spawn cold core cyclonic siblings, and

the areas between the two, or confluences, are particularly rich in marine life. The system is largely

wind-driven, and we can expect that anomalous hurricane years, for example, can result in largescale differences in gyre formation and resultant prey for marine mammals, sea turtles, and birds

(Biggs et al. 1996; Davis et al. 1998).

Thirty years ago, researchers and the public had only a vague impression that the deeper waters of

the Gulf harbor more than the near-shore bottlenose (Tursiops truncatus) and Atlantic spotted

(Stenella frontalis) dolphins of the inner shelf. It was David Schmidly and Susan Shane of Texas

A&M University (Schmidly and Shane 1978) who most concisely pointed out the Gulf’s amazing

cetacean diversity, knowledge gleaned largely from stranding records and the whaling literature on

sperm whales (Physeter macrocephalus). Indeed, there are sperm whale concentrations in at least

three areas, north of the Florida Keys, south of the Mississippi Delta, and just east of the TexasMexico border (Würsig et al. in press). At least another twenty toothed whales “commonly” occur

in Gulf waters, as well as two species of baleen whales, the generally tropical Bryde’s

(Balaenoptera edeni) and the near-cosmopolitan humpback (Megaptera novaeangliae) whales.

Clymene dolphins (S. clymene) and short-finned pilot whales (Globicephala macrorhynchus) prefer

shelf waters west of the Mississippi; spinner (S. longirostris) and Atlantic spotted dolphins prefer

those east of it; and pantropical spotted (S. attenuata) and striped (S. coeruleoalba) dolphins occur

in deep waters throughout the northern Gulf. We know that at least sperm whales and several of the

Stenella spp. are found more frequently than expected in and near confluences between ocean eddies

or gyres, and less frequently in warm anticyclonic rings. While present for much or all of the year,

most cetaceans change their locations based in part on seasonal conditions and in part on

unpredictable vagaries of ocean systems (Davis et al. 1999).

Besides the influences of depth, area, season, and oceanographic features, we expect that

geographically large-scale and temporally long-term changes in ocean climate can have profound

effects on cetacean abundance, distribution, and overall “health” in the Gulf. Such large-scale

changes would be induced by global climate change, and it is generally agreed that at present we are

in the midst of largely (or totally) human-induced global warming (IWC 1997; Tynan and DeMaster

1997). However, predictions of potential effects are fraught with difficulty. It is probable that ocean

warming will spawn more frequent and violent weather patterns including hurricanes, and may

change eddy formations, river input to the Gulf, salinities, and primary productivities in ways that

may strongly affect marine mammals. Only long-term monitoring of climate, ocean processes, and
81

marine mammals in the Gulf can bring hope of discerning potential and realized problems due to

global climate change (IWC 1996; Würsig and Ortega-Ortiz 1999).

Human action has had strong influences on marine ecosystems, especially by pollution and other

forms of habitat degradation near shore (see, for examples, Würsig 1990a; Leatherwood and

Jefferson 1997). In the Gulf of Mexico, high levels of bio-accumulated metals, PCB’s, DDT, and

other potential toxins have been found in near-shore bottlenose dolphins (Davis 1993; Salata et al.

1995). At the same time, an unusually high incidence of abnormal internal and external body

growths and lesions, some of which are pathological, have been found during necropsies of beach

cast dolphins (e.g., Cowan 1995). Links between toxins and pathologies have only rarely been made

for cetaceans, but see Aguilar and Borrell (1994) for an example, and Aguilar and Borrell (1996)

for excellent summaries.

Since petrochemical production is a major industry in U.S. waters, including the Gulf of Mexico,

the question of potential danger to marine mammals due to oil spills has been addressed (Geraci and

St. Aubin 1990). Pinnipeds are subject to oil fouling of the pelage, and consequent reduction of

thermoregulatory ability, especially by fur seals; baleen whales may suffer at least short-term baleen

fouling; and manatees(Trichechus sp.) could suffer poisoning if ingesting water and sea grasses in

oil-polluted near shore areas. However, it had been surmised that toothed whales, the predominant

marine mammal fauna in the Gulf, might not be subject to more than brief and mild physiological

damage since toothed whales do not generally ingest near-surface prey, and thermoregulate with

blubber instead of hair (Würsig 1990b). This belief was modified when it was found during a 1990

oil spill off Galveston, Texas, that bottlenose dolphins remained in even the very volatile freshlyspilled surface sheen and slick oil, apparently unable to detect a way out of the affected area.

Although no deaths of offshore bottlenose dolphins were detected as a result of the oil spill (due to

currents at the time, carcasses would have been unlikely to float ashore), the dolphins were inhaling

volatiles of potential danger to lung and other internal tissues (Smultea and Würsig 1995). It is

therefore probable that oil spills pose a threat to even toothed cetaceans who are mobile enough to

“easily” leave the area of the oil spill, but may not know how to do this. However, the magnitude

of such potential threat is unknown, and research is urged on this point.

It is known mainly from studies outside of the Gulf of Mexico, that dolphins and whales can be

affected to variable degree by human-made sound from boating and shipping; petrochemical

exploration, development, and extraction; and ocean science studies (such as loud low-frequency

sounds that synoptically measure ocean temperature by recording of speed of sound) (summaries

are in Richardson 1995, and Richardson and Würsig 1995, 1997). The petrochemical exploration

noise of “pinging” seismic exploration is particularly loud, and can affect behavior of cetaceans to

distances of tens of kilometers (for example, Malme et al. 1984). Short-beaked common dolphins

(Delphinus delphis) adjusted their movements at least by several kilometers in response to industrial

seismic activities (Goold 1996). While it has been asserted that sperm whales changed their

distribution patterns in response to seismic sounds in the Gulf (Mate et al. 1994), such reaction has

not yet been proven and remains to be studied.

Recent evidence indicates that types of calls and calling rates of whales and dolphins may be

affected by industrial noise (Rendell and Gordon 1999, long-finned pilot whale, Globicephala
82

melas), and by sounds of vessels (Lesage et al. 1999, beluga whales, Delphinapterus leucas).

Communication may be disrupted, altered, or masked by industrial noise (Greene 1995). Physiologic

changes, such as enlarged adrenal glands and shifts in hormone levels, have been documented in

terrestrial mammals subject to long-term noise (Harlow et al. 1992). However, clear physiologic

effects of stress have not been investigated in cetaceans, and this area of research is in obvious need

of attention.

Dolphins and whales are likely to have habituated at least to some aspects of high levels of shipping

noise and industrial activities, especially of the northern Gulf of Mexico; but it is presently unknown

what types and intensities of underwater noises may change the distribution patterns, habitat use,

general behaviors, or physiology of any of the cetaceans. Since large gyres and eddies seem

particularly important to at least several cetaceans (Davis et al. 1999), it follows that such areas of

high use by marine mammals have the potential of being most vulnerable to disturbance from

industrial activities and shipping. I suggest that reactions to disturbance be studied in dolphins and

whales inhabiting waters with presently or projected high amounts of human activity. Sperm whales

are a concern as a listed endangered species, and since very little is known about any of the smaller

toothed whales, or dolphins, one or two such species might be used as “indicators” for others. A set

of well-designed experimental studies, probably including controlled sound sources, underwater

acoustic measurements of the sources and the animals, and devices that monitor movements and

dives can be part of such work. There is a critical need for information on disturbance reactions of

cetaceans in the Gulf of Mexico, and it is hoped that data gaps are filled in as soon as possible in the

face of continuing and accelerating industrial use.

REFERENCES

Aguilar, A. and A. Borrell. 1994. Abnormally high polychlorinated biphenyl levels in striped

dolphins (Stenella coeruleoalba) affected by the 1990-1992 Mediterranean epizootic. Sci. Total

Environm. 154: 237-247.

Aguilar, A. and A. Borrell. 1996. Marine Mammals and Pollutants: An Annotated Bibliography.

Fundaci— pel Desenvolupament Sostenible, P.O. Box 94141, 08080 Barcelona, Spain. 251 pp.

Biggs, D.C., G.S. Fargion, P. Hamilton, and R.R. Leben. 1996. Cleavage of a Gulf of Mexico Loop

Current eddy by a deep water cyclone. J. Geophys. Res. 101:20629-20641.

Cowan, D.F. 1995. Amyloidosis in the bottlenose dolphin, Tursiops truncatus. Vet. Pathobiol.

32:311-414.

Davis, J.W. 1993. An analysis of tissues for total PCB and planar PCB concentrations in marine

mammals stranded along the Gulf of Mexico. M.S. thesis, Texas A&M University, College

Station, TX. 134 pp.

Davis, R.W., G.S. Fargion, N. May, T.D. Leming, M. Baumgartner, W.E. Evans, L.J. Hansen, and

K.D. Mullin. 1998. Physical habitat of cetaceans along the continental slope in the north-central

and western Gulf of Mexico. Mar. Mamm. Sci. 14:490-507.
83

Davis, R.W., Evans, W. E. and Würsig, B. 1999. Distribution and abundance of cetaceans in the

northern Gulf of Mexico. Volume II: Technical Report. Minerals Management Service and U.S.

Geological Service. Available from Gulf of Mexico OCS Region, MMS, 1201 Elmwood Park

Blvd., New Orleans, LA 70123, U.S.A. 319pp.

Geraci, J.R. and D.J. St. Aubin. 1990. Sea Mammals and Oil: Confronting the Risks. Academic

Press, San Diego, CA.

Goold, J.C. 1996. Acoustic assessment of populations of common dolphin Delphinus delphis in

conjunction with seismic surveying. J. Mar. Biol. Assoc., U.K. 76:811-820.

Greene, C.R. Jr. 1995. Ambient noise. In Marine Mammals and Noise, by W.J. Richardson, C.R.

Greene, Jr., C.I. Malme, and D.H. Thomson. Academic Press, San Diego, CA.

Harlow, H.J., F.G. Lindzey, W.D. Van Sickle, and W.A. Gern. 1992. Stress response of cougars to

non-lethal pursuit by hunters. Can. J. Zool. 70:136-139.

IWC. 1997. Report of the IWC workshop on climate change and cetaceans. 47th Rep. Int. Whal.

Comm: 293-313.

Leatherwood, S. and T.A. Jefferson. 1997. Dolphins and development in Hong Kong: A case study

in conflict. IBI Reports 7:57-69.

Lesage, V., C. Barrette, M.C.S. Kingsley, and B. Sjare. 1999. The effect of vessel noise on the vocal

behavior of belugas in the St. Lawrence estuary, Canada. Mar. Mamm. Sci. 15:65-84.

Malme, C.I., P.R. Miles, C.W. Clark, P. Tyack, and J.E. Bird. 1984. Investigations of the potential

effects of underwater noise from petroleum industry activities on migrating gray whale

behavior/Phase II: January 1984 migration. Report from BBN, Inc., Cambridge, MA, to MMS,

Anchorage, AK. 

Mate, B.R., K.M. Stafford, and D.K. Ljungblad. 1994. A change in sperm whale (Physeter

macrocephalus) distribution correlated to seismic surveys in the Gulf of Mexico. J. Acoust. Soc.

Amer. 96:3268-3269.

Rendell, L.E. and J.C.D. Gordon. 1999. Vocal response of long-finned pilot whales (Globicephala

melas) to military sonar in the Ligurian Sea. Mar. Mamm. Sci. 15: 198-204

Richardson, W.J. 1995. Documented disturbance reactions. In Marine Mammals and Noise, by W.J.

Richardson, C.R. Greene, Jr., C.I. Malme, and D.H. Thomson. Academic press, San Diego, CA.

Richardson, W.J. and B. Würsig. Significance of responses and noise impacts. In Marine Mammals

and Noise, by W.J. Richardson, C.R. Greene, Jr., C.I. Malme, and D.H. Thomson. Academic

press, San Diego, CA.
84

Richardson, W.J. and B. Würsig. 1997. Influences of man-made noise and other human actions on

cetacean behavior. Mar. and Freshwater Beh. and Physiol. 29:183-209.

Salata, G.G., T.L. Wade, J.L. Sericano, J.W. Davis, and J.M. Brooks. 1995. Analysis of Gulf of

Mexico bottlenose dolphins for organochlorine pesticides and PCB’s. Environ. Poll. 88:167-175.

Schmidly, D.J. and S.H. Shane. 1978. A biological assessment of the cetacean fauna of the Texas

coast. Final Report, U.S. Marine Mammal Commission, Wash. D.C. 38 pp.

Smultea, M.A. and B. Würsig. 1995. Behavioral reactions of bottlenose dolphins to the Mega Borg

oil spill, Gulf of Mexico 1990. Aq. Mamm. 21:171-181.

Tynan, C.T. and D.P. DeMaster. 1997. Observations and predictions of Arctic climate change:

Potential effects on marine mammals. Arctic 50:308-322. 

Würsig, B. 1990a. Human impacts on cetaceans. In Sea Turtles and Marine Mammals of the Gulf

of Mexico; Proceedings of a Workshop, Aug. 1-3, 1989. MMS Gulf of Mexico OCS Region,

New Orleans, LA. 211 pp.

Würsig, B. 1990b. Cetaceans and oil: Ecological perspectives. In Sea Mammals and Oil:

Confronting the Risks, ed. by J.R. Geraci and S.J. St. Aubin. Academic Press, San Diego, CA.

Würsig, B. and J. Ortega-Ortiz. 1999. Global climate change and marine mammals. In Proceedings

of the 1999 European Cetacean Society, ed. by P.G.H. Evans, Oxford Univ., U.K.

Würsig, B., D.J. Schmidly, and T.A. Jefferson. In press. The Marine Mammals of the Gulf of

Mexico. Texas A&M University Press, College Station, TX.

Dr. Bernd Würsig is Professor of Wildlife and Fisheries Science at Texas A&M University, and

Professor of Marine Biology at the Galveston Branch of the university. He is also Co-Director of

the Institute of Marine Life Sciences. Dr. Würsig has published three books as well as over 100

peer-review and popular articles based on his research on the behavioral ecology of whales and

dolphins. He recently finished a book entitled The Marine Mammals of the Gulf of Mexico, with

David Schmidly and Thomas A. Jefferson as his co-authors; this work was published by Texas

A&M University Press in March 2000 (ISBN 0-89096-909-4).
85

HUMAN ACTIVITIES AND NATURAL EVENTS: IMPACTS ON

GULF OF MEXICO MARINE MAMMALS, PART 2

Dr. Jeffery Norris

Texas A&M University

THE EFFECTS OF NOISE ON ANIMALS

In the marine environment, there are many sources of noise, as is true in any environment. We may

think that we understand how noise affects us, particularly loud noise, such as a jet flying overhead

or an explosion of fireworks. But few of us can imagine what a 240 dB seismic pulse sounds like

and what its affects might be when it is repeated at 15 second intervals for days on end. When a

noise like this is transmitted in water, which is a more efficient conductor than air, its effects are

tremendous. To put this example in perspective: a 10-pound charge of TNT exploded at a depth of

50 feet generates a signal of approximately 223 dB. (Urick 1983).

We humans are very rarely exposed to such sound levels, and it is hard to say how we would

respond if we were exposed to such sounds. It seems logical that any animal exposed to such signals

would have obvious and immediate responses. However, many sperm whales are exposed to just

such noises as a result of heavy seismic exploration off the mouth of the Mississippi River, and they

continue to inhabit this area. What can account for this? Is it that these signals do not bother the

animals or that they are so motivated to stay that they are willing to put up with the exposure? 

THE CURRENT REGULATORY ENVIRONMENT IN THE GULF OF MEXICO

The regulatory situation in the Gulf of Mexico is unlike that of anywhere else in United States.

Based on 1976 EIS and 1984 EA, a Categorical Exclusion (CE) has been granted for all seismic

activities in Gulf of Mexico, with no mitigation (MMS 1999). Under this exclusion, those in the

seismic exploration industry are free to shoot when and where they want without consideration of

the effects on marine mammals. The Minerals Management Service (MMS) has undertaken a series

of reviews of the current regulatory environment in the Gulf. MMS conducted an internal review

and concluded that some seismic activities now listed under the CE should be evaluated under an

EA to “verify that new technology or environmental information has not altered 1984

determinations” (MMS 1999). There is a pressing need to know direct, indirect, and cumulative

effects of seismic exploration signals on marine mammals. Their significance and degree to which

these effects are controversial bear on whether another categorical exclusion is granted or an IS is

required.

When considering seismic activity in the Central and Western Planning Areas of the Gulf of Mexico

in 1997 and 1998, the MMS concluded that the available information was insufficient to be

confident that seismic activities would not collectively have significant, adverse, long-term effects

on the size or productivity of any marine mammal species or population. The explicit concern was

adverse effects that might occur from repeated disturbances of vital functions such as feeding,

breeding, and nursing. It is worth noting that a CE does not automatically mitigate a take of marine
86

mammals. Further, a take of endangered species (such as the sperm whale) is prohibited. For small

take exclusions, as granted for example in Alaska, the take must be so small or unimportant to

warrant little attention.

The Marine Mammal Commission (MMC) in its 1998 Annual Report described the magnitude of

the problems with offshore oil development in the Gulf relative to cetaceans (MMC 1999). It noted

that an average of three to four seismic surveys are conducted every day in the northern Gulf of

Mexico. It would be safe to say that seismic signals, at some level, would be continuously audible

to any sperm whales in that area. Additionally, there are 1,000 boat trips, and 2,000 helicopter flights

per day. There are also 100 exploratory and development wells drilled every year-- many now in

deeper waters. The Commission described particular research needs, including determining whether

and how the distribution, abundance or productivity of any resident species or population may have

been affected by the seismic sound field.

Categorical Exclusions and other management tools can be maintained using mitigation techniques.

At worst, seismic signals can injure animals. Therefore, the minimum goal is to prevent either

permanent or temporary hearing damage. Developing standard procedures includes descriptions of

zones of influence and soft starts (ramp-up of signals). The High Energy Seismic Survey (HESS)

team, under contract with MMS, has described two zones of influence, a 180 dB isopleth-safety zone

against hearing damage and 140 dB Isopleth-zone of potential harassment.

THE BIOACOUSTICS OF THE INTERACTION

The interplay of an animal's auditory sensitivity, behavior and motivation relative to a seismic

signal's characteristics will determine the form and magnitude of its response. The auditory

thresholds have been described for a few small odontocetes (reviewed in Au 1993). A generalized

dolphin audiogram is presented in Figure 24. The upper thresholds are between 100-150 kHz, with

little sensitivity below 100 Hz. Peak sensitivity is typically between 20-80 kHz. Superimposed on

this audiogram are the spectra of their echolocation pulses and their whistles. Less is known about

the hearing of larger cetaceans. A hypothesized sperm whale audiogram is presented in Figure 25,

along with a spectrum of their pulses. The upper threshold is surmised to be at least an octave above

the highest signals in their pulses, while the lower sensitivities are thought to be a product of the

animal's overall larger size. Finally, a spectrum of a seismic pulse is overlaid on this hypothesized

audiogram, illustrating that the entire signal is likely to be audible to the whale. 

Assuming that an animal perceives a signal, its motivation to response may be highly variable. For

example, if it is migrating through an area ensonified by seismics, on the way to mating or calving

grounds, it may be more or less tolerant than if it were feeding in the area. The importance of its own

signals may bear on this tolerance range. If, for example, it is trying to communicate with

conspecifics, then the masking effects of a seismic signal, even at relatively low amplitude levels,

may prompt a response. To complicate matters further, a lack of apparent response as measured, for

example, by the animal' s not leaving an area, may provide no evidence that noise exposure is

increasing stress, which in turn may reduce the species' overall fitness through reduced reproductive

output. Such a response would only be evident through long-term studies.
87

Figure 25. Hypothesized sperm whale hearing threshold, with spectra of their pulses and seismic

exploration pulses.

Figure 24. Generalized dolphin hearing threshold, with the spectra of their echolocation pulses and

whistles.
88

GULFCET FINDINGS

The GulfCet program has gone a long way in determining the distribution and abundance of

cetaceans in the Gulf of Mexico. The MMS reports from this program provide detailed maps

indicating the distributions of the many species found in the Gulf (Norris et al. 1996). Three aspects

of the Gulf's cetacean community bear on the effects of seismic exploration signals: there is a large

and diverse community of dolphins, with approximately 14 species and more than 50,000

individuals; a large and stable population of sperm whales in the northern Gulf, some apparently

resident off the mouth of the Mississippi River; and finally, there are very few baleen whales,

probably less than 100 in the entire northern Gulf. 

 The large community of dolphins is likely to be relatively insensitive to seismic signals, and their

exposure is probably not significant. The opposite, however, is the situation for the larger species,

the sperm whale and baleen whales. These species are likely to be highly sensitive to acoustic

signals in the frequencies of the seismic exploration signals. These are the species, all endangered,

that are most likely to be affected by seismic signals and should be the focus of future research.

Changes in sighting frequency relative to seismics have been studied by Ms. Shannon Rankin

(Rankin 1999). Relative intensity of seismic signals was estimated from the signal-to-noise ratio

(signal intensity in decibels above ambient). Signal-to-noise measurements were divided into three

categories: 0 dB (no seismic signals), 0-12 dB, and >12 dB above ambient. Additionally,

hydrographic data were analyzed for potential interdependencies between hydrographic features,

seismic exploration and presence of cetaceans. For GulfCet I, hydrographic features were defined

by sea surface height measured by satellite altimetry. For GulfCet II, major hydrographic features

were determined by shipboard CTD and XBT data which was then used to compute dynamic sea

surface height. Five hydrographic regions were defined: cyclone, anticyclone, periphery of the eddy,

confluence zone, and “other” areas outside these defined features.

Over 514 hours of “on effort” recordings covering approximately 6,819 km of survey effort were

used. A total of 108 hours, or 21% of the total time, contained sounds associated with seismic

exploration. The percent time with seismic exploration sounds was 10% for GulfCet I and 34% for

GulfCet II. The final cruise of GulfCet II had the greatest percentage of seismic exploration sounds,

with pulses present 50% of the time. These sounds were not uniformly distributed in the study area,

but were concentrated in areas on the upper and mid-continental slope.

There was no significant difference between the overall sighting rate and the sound level when

tested for each of the hydrographic regions. Distributions of two species were additionally

examined. The sperm whale sighting rate did not differ significantly between the different sound

levels for any of the hydrographic features. The sighting rate of the pantropical spotted dolphin was

found to be significantly higher for the >12 dB areas within the hydrographic feature defined as

“other” (P2 = 10.26, p = .005). The sighting frequencies for the remaining hydrographic features did

not differ significantly by sound level. 

The influence of the scale of observation is important when describing the reaction of animals to

noise. There are a number of alternative explanations for the observed distributions that lead to the
89

finding of no significant change in cetacean sighting rate relative to noise exposure, even controlling

for hydrographic features. It is possible that the observed cetacean distributions may be due to

displacement of cetaceans away from the sound source and, at least sometimes, towards our survey

vessel (Figure 26). This displacement may lead to an artificially increased sighting rate, which is

opposite of the expected distribution if the animals are negatively influenced by the seismic signals.

However, if the cetacean survey vessel was close to the seismic survey vessel, in response to the

same flight of animals away from the perturbation, sighting rates would be lower. Lastly, if the

animals had responded to the presence of the seismic signal and fled before the cetacean survey

vessel had entered into the area, there also would be a decreased sighting rate. Recommendations

for appropriate research are made below.

 Seismic exploration signals were, as described above, encountered very often during GulfCet

cruises. Most signals were of a relatively standard form, with the main energy of the pulse between

100-900 Hz, with one of two echoes, typically below 100 Hz. On a number of occasions, we

encountered other signals broadcast from seismic survey vessels. This included a loud seismic shock

centered at 2.5 kHz, with little energy below 1 kHz (Figure 27). This figure displays sperm whale

pulses as well as three seismic pulses; first the 2.5 kHz pulse, then a more typical seismic pulse

below 1 kHz, and finally an echo. This first pulse has the same frequency content of a sperm whale.

On other occasions we recorded relatively high frequency pulses, which were apparently produced

by transducers placed on the seismic arrays to determine their precise location. I'm told that the array

location system that we recorded is no longer in service, but that higher frequency systems, centered

between 25-45 kHz are now being used. These signals would be very audible to dolphins. 

RECOMMENDATIONS FOR FUTURE RESEARCH

It is appropriate, after eight years of research on these matters, to make recommendations for future

research and information needs. 

A. Disturbance Responses of Sperm Whales to Seismic Exploration Signals

1. Before, during, and after study of responses of sperm whales to seismics using seismic

vessel and marine mammal survey vessels

2. Telemeter whales to record received levels and incidence of exposure

3. Monitor noise levels using buoys

B. Behavior study of sperm whales off the mouth of the Mississippi River. Long-term study of

the resident animals, using oil platforms and sailboats. These studies could be low cost and

would determine how a known group of animals are responding to seismic exploration.

C Maintenance of centralized data base of seismic exploration activity, with spectra of signals,

cruise plot

D. Retrospective analysis of GulfCet data relative to known positions of seismic vessels.
90

Figure 26. The influence of scale on rate of dolphin encounters relative to seismic signals. The rate

should vary according to the scale of investigation, with decreased sighting rate at low

and high scales, but increased rate at intermediary scales.
91

Seismic Pulses

Sperm Whale Pulses

Sperm Whale Pulses

Seismic Pulses

6

4

2

kHz

20

10

0

-10

-20

microPa

0 1.0 2.0 3.0 4.0 Seconds

Figure 27. Spectrogram (top) and waveform (bottom) illustrating sperm whale pulses and two forms

of seismic signals. The spectrogram displays frequency (y-axis) as a function of time

(x-axis) with increased darkness indicating increased amplitude. The waveform displays

amplitude over time. Eight sperm whale pulses are indicated, with center frequency at

approximately 2.5 kHz. The first seismic pulse is also centered at 2.5 kHz, with little

energy below 1 kHz. The second pulse is centered at 900 Hz. The final pulse, centered

at less than 100 Hz, is an echo.

REFERENCES

Au, W.W.L. 1993. The Sonar of Dolphins. Springer-Verlag. New York, New York.

Marine Mammal Commission, 1999. Annual Report to Congress 1998. Marine Mammal

Commission, 4340 East-West Highway, Room 905. Bethesda, Maryland 20814

Minerals Management Service, 1999. Request for Proposal 1435-01-99-RP-30987, Preparation of

an environmental assessment on geological and geophysical exploration for minerals resources

on the Gulf of Mexico Outer Continental Shelf. Minerals Mgmt. Service, Department of the

Interior, Washington, D.C. 

Norris, J.C., W.E. Evans, R. Benson, and T.D. Sparks. 1996. Acoustic surveys. pp. 133-187 In R.W.

Davis and G.S. Fargion. Distribution and abundance of cetaceans in the north-central 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 Fisheries

Service. U.S. Dept. of the Interior, Minerals Mgmt. Service, Gulf of Mexico OCS Region, New

Orleans, LA.
92

Rankin, S. 1999. The potential effects of sounds from seismic exploration on the distribution of

cetaceans in the northern Gulf of Mexico. Masters Thesis. Texas A&M University, College

Station, Texas. 64 pp.

Urick, R.J. 1983. Principles of Underwater Sound. McGraw-Hill Book Company. New York, New

York.
93

HUMAN ACTIVITIES AND NATURAL EVENTS: IMPACTS ON

GULF OF MEXICO SEA TURTLES

Dr. David Owens

Texas A&M University

INTRODUCTION

Nearly ten years ago Michael J. Weber was asked to present a similar review of the general situation

for sea turtles in the Gulf of Mexico (Weber 1990). He did a very good and very thorough job of

outlining the diverse concerns of scientists, conservationists and policy people regarding these

endangered and threatened species. I urge you to refer back to that important paper, as well as to a

more recent review by Lutcavage and co-authors (1997) which gives up-to-date detail on human-sea

turtle interactions. Regarding sea turtles, it is actually amazing to me how little our primary concerns

have changed in the intervening decade. I do think the global concerns for the Gulf of Mexico are

changing so my goal today is to suggest how sea turtles may fit into the bigger picture. 

At the outset, I should emphasize that we appear to have made some real progress in understanding

what we need to do to recover the sea turtles and to protect them in their marine habitats. The

biggest single problem for sea turtles then and now, and in fact for the past 50 years has been their

accidental capture in trawling gear. The National Research Council report of 1990 made this case

very carefully and the biological problem has not really changed that much since then (Magnuson,

et al. 1990). While the populations are showing some signs of a recovery phase, the problem is that

there are still way too many immature and adult sea turtles floating up dead along the coast of the

Gulf of Mexico (see others, this report). In addition to the trawling problem, I would now like to list

the other impacts that I am aware of in three categories: 1) Human Impacts, 2) Impacts of Unknown

Cause and 3) Natural Impacts. Finally, I will attempt to provide some “BOLD OLD”suggestions of

how I think we can actually solve the Marine Resource use problems of the Gulf of Mexico. 

IMPACTS OF HUMAN ACTIVITIES

Complications of Recovery

The most important human impact is the chance we have to correct our mistakes and help species

and habitats to recover. The irony of the apparent recovery of sea turtles is that as the populations

do better because of extensive conservation programs, more individual turtles will “get in the way”

of shipping, boaters, fishermen, and trawlers and thus be negatively impacted by various human

activities. As turtle populations increase, more loggerheads will take up residence on offshore

platforms, more adult ridleys will forage in prime shrimping grounds and more juvenile ridleys will

attempt to raid the crab traps set in shallow waters or grab the baited fish hooks of sport fishermen.

Further confounding the recovery of these species is the fact that human rapid coastal population

growth is directly and indirectly competing for much of the same habitat that the turtles need.
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Commercial Fishing

Increased effort in trawling for shrimp and fish corresponds well with the decline of the Kemp’s

ridley (Lepidochelys kempii) in the Gulf of Mexico. While it is often stated that egg collecting at the

primary nesting beach of Rancho Nuevo in Tamaulipas, Mexico was an important cause for the

decline of the species, I do not believe this. In the 1950s fishermen out of Brownsville would

routinely catch 50+ turtles per trip, eating a few, selling a few and dumping the dead ones overboard.

The earliest records of sea turtle migrations in the Gulf of Mexico were from tag returns from

nesters tagged at Rancho Nuevo and trawled up by helpful shrimpers off Louisiana.

Other fishing methods are also of concern. In particular, the longline fishery for billfish and tuna.

Since this is usually a deep water fishery, the sea turtles most often impacted are the leatherback

(Dermochelys coriacea). Recent high levels of stranded dead leatherbacks in the Gulf of Mexico

(Shaver pers. comm.) also suggests that their love of jellyfish brings them into shallow water for

foraging on wind rows of cabbageheads. I have personally seen many leatherbacks foraging just

outside the surf along the south Texas coast in water that could not have been more that four meters

deep. I have also seen increasing numbers of butterfly nets in recent years. A concern here is that

these shallow working nets will capture the juvenile Kemp’s ridleys, which seem to prefer the

shallower waters near passes and in the estuaries. 

Petrochemical Industry

My feeling is that loggerheads (Caretta caretta) and possibly hawksbills (Eretmochelys imbricata)

in the southern Gulf are actually attracted to hard substrate and that the placement of oil and gas

exploration/production platforms and stone jetties in the Gulf of Mexico has actually created habitat

for these species. The fact that so many loggerheads use the Flower Gardens Banks supports this

natural attraction. What is frustrating is that, despite several years of studies, we still know very little

about what these turtles are doing, when they use the platforms, what they eat and what their long

term migration patterns are. Rig removals can be a problem for the turtles; however, my impression

is that several good protocols have been developed which save turtles each year. The seismic

exploration, ship traffic and potential for spills are all serious problems which are more difficult to

sort out. Granted, large numbers of animals may not be impacted at this time; however, if the

populations are now at 10% of their historical levels, what seems to be a small problem now may

be huge as the populations recover. The worst case scenario for sea turtles in the Gulf of Mexico

would be major spills near important nesting beaches for hawksbills in Campeche, Mexico; for

Kemp’s ridleys at Ranch Nuevo, Mexico and Padre Island, Texas and for loggerheads in

southwestern Florida and the Chandeleur Islands off Louisiana. The aggregating behaviors seen in

sea turtles mating offshore and beach nesting has the low probability potential for a major

population disaster such as the 1979 Ixtoc spill which reached Rancho Nuevo and Padre Island with

weathered oil. Had the spill been one month earlier, when many more turtles were in the area, it

could have been a major disaster for sea turtles, including eggs and adults. Turtles do eat tar balls

( which are sometimes naturally occurring) along with lots of plastic and latex, which can kill them.

They may also be impacted by floating oil derivatives, especially on nesting beaches and potentially

in sub-lethal disease synergisms (see below). 
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Agricultural and Urban Runoff

Sea turtles naturally live a long time and, except for the juvenile and adult green turtle, are predators.

They are known to bioaccumulate DDT and its metabolites DDE and DDD. The concern expressed

by Lutcavage et al. (1997) is that immune suppression may be occurring and that this could account

for increased levels of fibropapilloma disease (see below). 

Other Clear Impacts

Several other human related activities are now considered to be modest problems for sea turtles but

could develop into much more important concerns as both human and turtle populations increase.

In particular, capture in channel dredges, boat strikes and incidental capture by hooks in sport

fishing will probably each increase as problems for turtles over time. 

IMPACTS OF UNKNOWN CAUSE

Three phenomena have been on the increase which, while not adequately documented to be purely

human induced, are more than likely related to the huge growth of human populations in the coastal

areas. The first, and the most frightening, is the apparent increase during the 1980s in the debilitating

disease known as fibropapillomatosis (George 1997). This disease is probably viral in origin but,

despite several years of research, has not been explained. The disease is most prevalent in green sea

turtles (Chelonia mydas) where it is known as GTFP, but has been described in all species except

the leatherback. Interestingly, the disease is not now seen in the northwestern Gulf of Mexico.

However, as Bob George states (1997) “Turtles frequenting near-shore waters, areas adjacent to

large human populations, and areas with low water turnover, such as lagoons, have a higher

incidence of GTFP than individuals in deeper, more remote waters.” My concerns are that with

rising water temperatures (correlates with increased disease levels) due to global warming and with

the rebounding numbers of currently highly dispersed sea turtles, we may see contagious epidemics

of this disease developing in the future. 

The second concern I have is the extent of the hypoxia/anoxia phenomenon in the northern Gulf of

Mexico (Harper 1999). While these have long been known from places like Mobile Bay and Laguna

Madre, one can not help but be concerned about their potential impacts on food resources for sea

turtles. Indeed, the largest described hypoxic area, which is off western Louisiana, is in the midst

of what may be the single most important adult foraging grounds for Kemp’s ridleys. 

The final area of potential human derived impact is the harmful algal bloom situations where there

is evidence of “a disturbing trend of increasing frequency” (Buskey 1999). All three of these poorly

defined phenomena seem to me to be symptomatic of a marine stress syndrome, for lack of a better

descriptor, which indicates a general degradation of the Gulf of Mexico in a way which has never

before been experienced.
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NATURAL IMPACTS

Sea turtles are well known to experience cold stunning. They typically attempt to avoid cold water

when possible; however when trapped will sometimes appear to hibernate when conditions are right

(Moon et al. 1997) or sometimes die in a few hours when temperatures go below about 8°C (Spotila

1997). Trapping appears to happen on a fairly regular basis in areas like Laguna Madre and the

Indian River of Florida where there are a very limited number of openings to the ocean. Since we

have not had a severe cold stunning event in several years, we unfortunately can expect a major kill

of sea turtles in the near future. 

BOLD OLD RECOMMENDATIONS FOR THE GULF OF MEXICO

My primary concern for the Gulf of Mexico and for sea turtles, after 21 years of observing them,

is less for the human impacts that we are clearly able to document and do something about and more

for the unknown or poorly understood problems which seem to be increasing in their extent and

potential negative consequences. At a Sea Grant sponsored meeting last summer (Sharing Our Gulf:

A Challenge for Us All) several of us here and an enthusiastic group from many backgrounds

attempted to get a better understanding of what has been done, what is working and what needs to

be done. The proceedings of that meeting will be published soon (Owens, in press) and I am sharing

with you here the “Recommendations and Ideas for the Future” section which were hammered out

during the meeting and by a small subset of us who met subsequently to refine the suggestions. 

An Education Program

The problem is that we still do not have an ethic of resource husbandry for the Gulf of Mexico.

Think of what Smokey the Bear has meant for our forests and you will just scratch the surface of

what is envisioned as an intense bilingual education campaign for the U.S., Mexico and Cuba. The

consensus of the Sharing Our Gulf meeting was that there is a serious need for the development of

new forms of communication across all agency, private sector, user group and country boundaries

using and depending on the Gulf of Mexico. Always mentioned was the Gulf of Mexico Program

with Sea Grant, M.M.S. and N.O.A.A. as the agencies that will have to provide the leadership and

financial resources to get this new education program and highly interactive communication system

off the ground. More involvement of the other two countries of the Gulf of Mexico is also seen as

essential. 

Basic Research

Many of the important questions we are now considering suffer from the fact that so few scientists

can get funding to delve into their underlying biology, oceanography and geology of these questions.

In my case, just as an example. It has been years, for example, since I have been able to get a basic

grant funded to work on sea turtle reproduction. And yet I am continuously being asked about

endocrine disruptors when I still know very little about how the real endocrine systems work in sea

turtles. 
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A Marine Preserve System

I suggest using the National Marine Sanctuary Program as a model to establish a set of protected

areas which can clearly be identified as essential to the Health of the Gulf of Mexico. In particular,

several wetland/estuary areas around the Gulf, the marine areas off Padre Island, the Chandeleur

Islands, the Yucatan Peninsula and hard-bottom areas off the Florida west coast would be good

places to start.

REFERENCES

Buskey, E.J. (in press). Harmful algal blooms in the northern Gulf of Mexico. In Owens, D. W., ed.

Proceedings of Sharing Our Gulf: A Challenge for Us All. Texas A&M Sea Grant Program. 

George, R. H. 1997. Health problems and diseases of sea turtles. In P. Lutz and J. Musick, eds. The

Biology of Sea Turtles. CRC Press. pp.363-385.

Harper, D. E. (in press) The hypoxia/anoxia phenomenon in the northern Gulf of Mexico. In Owens,

D. W., ed. Proceedings of Sharing Our Gulf: A Challenge for Us All. Texas A&M Sea Grant

Program. 

Magnuson, J., K. Bjorndal, W. DuPaul, G. Graham, D. Owens, C. Peterson, P. Pritchard, J.

Richardson, G. Saul, C. West. 1990. Decline of Sea Turtles: Causes and Prevention. National

Academy Press. Washington D.C.

Moon, D.Y., D. MacKenzie and D. Owens. 1997. Simulated hibernation of sea turtles in the

laboratory: I. Feeding, breathing frequency, blood pH, and blood gases. Jour. Exp. Zool.

278:372-380.

Lutcavage, M. E., P. Plotkin, B. Witherington and P. Lutz. 1997. Human impacts on sea turtle

survival. In P. Lutz and J. Musick, eds. The Biology of Sea Turtles. CRC Press. pp.387-409.

Owens, D. W., ed. (in press) Proceedings of Sharing Our Gulf: A Challenge for Us All. Texas A&M

Sea Grant Program.

Weber, Michael J. 1990. Human activities and sea turtle conservation in the Gulf of Mexico. In

Tucker and Associates, Inc., Sea Turtles and Marine Mammals of the Gulf of Mexico,

Proceedings of a workshop held in New Orleans, August 1-3,1989. OCS Study MMS 90-0009.

New Orleans, LA 211 pp.

David W. Owens was born in Illinois and spent three years as a Peace Corps Volunteer to the Fiji

Islands between 1968-1971. There he worked as a fisheries biologist doing projects on the Crownof-Thorns seastar, reef fishing methods and curriculum development. He earned his Ph.D. at the

University of Arizona and a Postdoctoral Fellowship at Colorado State University, completing
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several projects on sea turtles and trout. He was at Texas A&M for 21 years where he specialized

in sea turtle reproductive biology. He is the past president of the Annual Symposium on Sea Turtle

Conservation and Biology. In August 1998 he began a new job as Director of the Marine Biology

Graduate Program at the University of Charleston.
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REVIEW OF RELATED RESEARCH AND MONITORING PROGRAMS

ROLE OF A NON-GOVERNMENTAL IN GULF

PROTECTED SPECIES CONCERNS

Ms. Sharon Young

Humane Society of the United States

Although non-governmental organizations (NGO’s) sometimes fund research efforts by nongovernmental scientists, the easy description is that it is often our role to make life more difficult

for regulators. We use the tools at hand: education, lobbying and litigation to do what our

constituents wish us to do, and that is to protect animals and their habitats.

Conservation NGOs regularly argue for use of the precautionary principle when considering what

activities may be acceptable. At this juncture, our largest concern is often not what we DO know but

what we DON’T know about marine animals and their habitats. There are a number of concerns and

research needs that are germane to this workshop:

CRITICAL RESEARCH NEEDS

1. Determining the demographics of bottlenose dolphins, including completing studies to

determine stock discreteness

2. Evaluating and improving the Gulf of Mexico Marine Mammal Stranding Network 

3. Characterizing and monitoring key components of habitat in the Gulf that affect distribution

and may be more vulnerable to disturbance

4. Monitoring of population abundance, distribution, and habitat use 

5. Long-term monitoring of levels of environmental contaminants and natural biotoxins and

human impacts on populations

At this point, I want to note that when I was preparing for this presentation, I started with a list of

my general concerns. The list that I have just presented is a condensation of a list of concerns and

research needs that were identified for marine mammals in the proceedings of the August 1989

workshop that was held by MMS in New Orleans. I was chagrined to find that with the exception

of number two, the list for 1989 was virtually identical to my concerns in 1999.

I sincerely hope that if we are all back in New Orleans in 2009, significant progress will have been

made in addressing gaps in our knowledge and the discussion of this list will be focused on all that

we have learned to address the concerns rather than the list being repeated 20 years later with little

new information gained. 

I want to discuss each of these points more specifically and discuss how we, in the advocacy

community can help in gathering information to further our knowledge.
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With regard to research need number one, bottlenose dolphins (Tursiops truncatus) are among the

most commonly stranded animals and appear to be one of the most commonly sighted species in the

Gulf. Yet there is on-going controversy about their stock identity. The National Marine Fisheries

Service (NMFS) has determined that there are approximately 40 separate stocks of bottlenose

dolphins residing in bays, sounds, and estuaries; it also has separate stocks of coastal and offshore

dolphins. Many in the scientific community believe that some or all of these population units may

not be appropriate. Little research has been funded to answer important questions about stock

definition. The Humane Society of the United States (HSUS) is very concerned with the low funding

priority this issue has received. We have also expressed consternation that high levels of mortality

in commercial fisheries, including deaths in the medhaden purse seines in the Gulf of Mexico have

not been reduced, despite requirements of the Marine Mammal Protection Act (MMPA). The HSUS

has informed NMFS of its intent to file suit over the failure to address mandatory bycatch reduction,

maximum levels of which are determined according to abundance data for specific stocks. Any court

ruling would likely expedite research funding to assist in answering these questions of stock identity.

With regard to number two, stranding networks are key to helping collect information on sources

of mortality and the animals most likely to be affected. These networks must have adequate funds

to enable them to conduct thorough necropsies and tissue analyses to assist in answering many

questions relating to stock identity and sources of risk to animal health. Just last week, I provided

testimony to Congress in support of a proposed addition to the MMPA that would provide direct

grant funds for stranding networks to enhance their response and analytical capabilities. We will

continue to advocate for adequate funding for stranding networks.

Research need number three deals with key habitats for marine mammals. It is important that we

understand why animals are found where they are found. The GulfCet program has taken some

important first steps toward identifying areas of high use and beginning to model their importance.

We in the advocacy community have been working hard to obtain priority funding to develop

predictive models of animal distribution. Much of our effort has been focused on obtaining funds

for modeling right whale distribution on the east coast. We are hopeful that progress in that area will

lead to development of software to allow ocean and climatological information and information on

geologic and oceanographic features to be used to predict distribution for other species. The success

of this modeling is predicated on answering some of questions inherent in the last two bullets on the

list.

Since the workshop in 1989, the GulfCet Program has done much to help us to better understand

population abundance and distribution in the Gulf of Mexico. It has also helped our awareness of

factors that may affect their distribution, such as cold core rings and the Mississippi freshwater

plume. Yet reports from this program acknowledge the need for additional studies including

expanded use of telemetry, focal studies and combined aerial and shipboard studies to expand our

knowledge of the abundance and distribution of marine mammal and turtle species. These studies

are also important to establish both a baseline and a long-term monitoring strategy that identifies

important habitat for particular segments of the population as they forage, rest, reproduce or transit

the Gulf. We can assist these efforts by advocating for on-going surveys and increased funding.
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It is number five that is of particular relevance to this workshop. We continue to have only the most

rudimentary information on pollutants and naturally occurring biotoxins. Since the 1989 workshop,

we have learned more about the impact of some human activities, but we still know little about

others. 

POSSIBLE SOURCES OF HUMAN IMPACT

• Coastal Development (run-off, marine dumping and dredging)

• Offshore oil and gas development

• Recreational and commercial vessel traffic

• Military exercises and activities

• Commercial fisheries (actual bycatch, ghost gear, resource competition)

• Pollution from oil spills, agricultural run-off, industrial effluent, marine debris

• Live captures for display and research

• Illegal shooting

• Use of explosives to remove offshore structures

• Whale watching and dolphin feeding

• Natural factors such as algal blooms, epizootics, hurricanes, climate change

This last potential impact may not seem to be related to humans; however, some research has

indicated that harmful algal blooms may be related to human activities such as aquaculture

expansion in concentrated areas. Despite claims to the contrary, even some aspects of climate

change appear to result from human activities.

As we examine this list, live captures are one of the only factors whose impact on populations has

probably been reduced. As to the others, I suspect that we really know little about the extent of their

potential adverse activities but might suspect that for some, the effect may be significant (e.g.

fishery-related mortality).

As an advocate for the animal welfare community, I need to know the degree to which an activity

may be affecting an animal or a population. If it causes a significantly adverse impact, then I will

want to do something about it (more about what I would do later). Determining the impact is not

always easy (Figure 28).

Dan Costa presented a paper at the 1997 meeting of the American Fisheries Society, in which he

discussed how we can evaluate the impacts of noise. I have adapted it for use in a more general

context.

What the law requires may not be adequate. A survey that finds animals of some species in the area

does not mean that other more sensitive animals have not been affected and perhaps displaced from

former habitat. We know little about the stocks that inhabited the Gulf of Mexico before the advent

of offshore oil drilling. Animals that once may have been seen in abundance may now be rare. For

example, bottlenose dolphins may be more resistant to a potential adverse impact and still be seen

in an area, while animals such as beaked whales and Brydes whales may be more sensitive and may

have been displaced. 
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Noting that animals continue to feed in the presence of noise does not mean that they are not

affected. Animals that are significantly affected at a sub-lethal level may not realize the degree of

their incapacitation and its affect on their future survival until it is too late. For example, factory

workers have been known to work under unsafe conditions with intense noise that eventually

deafens them or breathing contaminants that eventually cause lung cancer, yet in their desire to

obtain resources (money) they tolerate the poor conditions and may be unaware of the danger they

court until it is too late to reverse the damage. We insist on a precautionary approach to human

health. We must approach the health of the ocean ecosystem and its inhabitants with some care as

well.

Determining Impacts on Protected Species

Legal Definitions:

• Definitions of take, harassment, jeopardy, negligible

impact

• Threshold of impact is usually observable changes in

behavior, abundance or distribution

• Legal thresholds still allow adverse impacts

Biological Definitions:

• Health and stability of populations

• Habitat utilization

• Short term effects (acute)

- Change in behavior

- Change in distribution

- Temporary physiological changes

• Long-Term Effects (chronic):

- Abandonment of habitat

- Permanent damage/serious injury

- Decline in population

Figure 28. Determining impacts on protected species.
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Unfortunately, this approach is rarely taken. In particular, noise proliferates with little concern being

raised. Dan Costa of the University of California commented to the 1997 meeting of the American

Fisheries Society that the ambient level of sound in oceans of the northern hemisphere has increased

20 decibels in the past 50 years. A Marine Mammal Commission report stated that in 1998 there was

an average of three to four seismic surveys in the northern Gulf of Mexico each day and more than

100 exploration and development wells drilled every year. Furthermore, each day there is an average

of over 1,000 boat trips and 2,000 helicopter trips to transport personnel and equipment. This

activity is a not an insignificant contributor to noise in the ocean.

In their 1998 report to Congress, the Marine Mammal Commission noted that “because exploration

and development have been going on in the northern Gulf for 40 years, it is possible that all of the

potentially affected marine mammal species have become accustomed to the noise and are no longer

affected by it. It is also possible that some or all of the potentially affected species have altered their

habitat-use patterns to avoid noisy areas.” Further that “such effects could be species-specific, agespecific, or area-specific.” The significance of the habitat displacement depends on the productivity

and importance of the area from which they have been displaced. As noted above, because we know

so little about the importance of particular areas to some or all members of a species or population,

we cannot hope to understand the significance of displacing them, if indeed we can even detect that

displacement has occurred.

However, because monitoring for the biological evidence that we seek is expensive and difficult,

it is often forsaken. Because of the arcane nature of issues like noise pollution, it is difficult for

advocates to mount campaigns to heighten awareness or curtail projects that inject more and more

noise into the environment.

In considering the impacts of expanded exploration for oil and gas in the Gulf and the demolition

of existing structures, it is important that impacts of a single factor be considered in the light of the

cumulative impact from other factors. A species or population, such as bottlenose dolphins, may be

killed in commercial fisheries, shot for preying on fish near boats, exposed to significant levels of

pollutants, disturbed by continual pursuit from whale watch boats, and suffering periodic mass

mortality due to harmful algal blooms. If we add to this exposure to increased sound levels that

displaces animals into more marginal foraging habitat, disrupts their social behavior or causes a

minor but permanent threshold shift in their hearing, we may find that the effect is almost

synergistic. Each factor in and of itself may not cause a population level problem, but when added

together, the impact may be severe. When it comes to evaluate impacts on endangered species, we

must remember that the goal should not be simply to avoid jeopardizing the continued existence of

the species (as it stipulates in the Endangered Species Act) but to recover depleted populations to

abundance. This is often overlooked.

There are a number of concerns with offshore oil and gas exploration and production that were on

the list of possible human impacts. I’m sure that you are all aware of them, but I will briefly re-state

them:
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• Adverse effects of spills, leaks, and disposal of platform-related debris

• Vessel collisions with marine animals

• Disruption of benthos or suspension of harmful particulate

• Adverse impacts from noise 

• The effect of blast trauma on animals

• Changes to ecosystem from erection/demolition of structures

• Ability or inability to monitor impacts of these activities

WHAT IS THE MINERALS MANAGEMENT SERVICE TO DO?

MMS must expand its contributions to funding of projects to monitor populations and effects of its

permitted activities. I also believe that it is appropriate to charge beneficiaries of the resource

exploitation for the cost of determining the effect of removing the resource. This is often done in

other industries. It might be required as a condition of obtaining a lease or permit.

MMS can encourage research and development of less intrusive technology. Perhaps we need to

offer incentives to develop new technologies that are quieter and more risk averse by requiring

additional research and development as a condition of obtaining a lease. I note that progress in

developing technology to significantly reduce emissions in automobiles came only after it was

federally mandated, and over the protests of the industry that it was not fiscally feasible.

 It is particularly important that the MMS, in conjunction with its partners, undertake monitoring in

areas in which there is a proposal to expand activities. Baseline studies of abundance and

distribution of protected species and habitat use patterns must be undertaken PRIOR to expansion

of exploration, production or demolition. We must also attempt to determine the source and intensity

of sounds, and set limits on acceptable levels, locales, or conditions under which sounds may be

generated.

MMS must assist in mapping important or high-use habitat areas for marine mammals and turtles

and prohibit or severely limit activities in those areas to reduce possible risk. With regard to noise,

we must remember that some sounds may affect movements or behavior for several kilometers

under the right conditions.

AS AN ADVOCATE, WHAT IS MY ROLE IN THIS PROCESS?

When I am aware of particular needs, I will advocate on behalf of needed funding from Congress.

I can help in the development of public or industry awareness programs. I can help make regulators

or legislators more sensitive to conservation concerns by lobbying or educating them on behalf of

the animals who will be affected. I can become a part of international efforts to provide protection

that extends beyond U.S. boundaries—in this case into Mexico and the wider Caribbean. I can

provide comments on regulatory or legislative proposals, attempting to highlight missing or

important informational needs that should be met. Last, I can sue somebody. Litigation is not the
105

best management tool, but it has become increasingly important in a world of squeaky wheels that

beg for grease and it can be used to help me in my role. My role is to protect animals by insuring

that there is compliance with protective legislation; and by providing a voice for them when they

cannot speak on their own behalf, I can ask that the same precautions we seek for ourselves be

extended to them.
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*

Roger Gentry made this presentation for Dr. Rowles, who was attending a Congressional hearing on the Marine

Mammal Rescue Assistance Act, a bill to provide a funding mechanism for eligible stranding programs.

MARINE MAMMAL STRANDING NETWORKS AND

ENVIRONMENTAL CONTAMINANTS

Dr. Teri Rowles*

Office of Protected Resources

National Marine Fisheries Service

The National Marine Fisheries Service (NMFS) is one of two lead agencies responsible for

administering the Marine Mammal Protection Act (MMPA). The Marine Mammal Health and

Stranding Response Program (MMHSRP) was formalized by the MMPA Amendments of 1992, and

this presentation described not only the Gulf of Mexico component of this program, but also

highlighted the need for national and international coordination of stranding network activities.

The MMHSRP goals are (1) to facilitate collection and dissemination of reference data and to assess

health trends; (2) to correlate health with available data on physical, chemical, environmental, and

biological parameters; and (3) to coordinate effective responses to unusual mortality events. To

accomplish these goals, the MMHSRP has five primary components: (1) marine mammal stranding

networks; (2) investigation of unusual mortality events; (3) biomonitoring; (4) National Marine

Mammal Tissue Bank; and (5) analytical quality assurance.

Through a national coordinator and five regional coordinators (the entire Gulf of Mexico coastline

is in the NMFS Southeast Region), NMFS oversees, coordinates, and authorizes stranding response

activities, provides training to personnel, and collects data from strandings. To respond to these

strandings, volunteer stranding networks have been established in all coastal states. When animals

strand dead, samples are collected not only to determine cause of death, but also to provide data on

biology and health for management activities. Research topics may include the following: life

history parameters, general health, disease trends, and the effects of chemical contaminants, as well

as other human activities on these animal populations. The Southeast Fisheries Science Center has

a regional stranding database that has near-real time reporting. This data may then be transferred to

the national stranding database and for cetaceans to the Marine Mammal Event database at the

Smithsonian Institute, National Museum of Natural History. 

The network responded to approximately 33,000 strandings around the nation from 1990-1998.

Approximately two-thirds of these strandings consist of seals and sea lions, with cetaceans making

up the remainder. During 1993-1998, there were 2,500 cetacean strandings in the Gulf of Mexico;

these included two unusual mortality events for cetaceans.

The 1992 amendments also established the Working Group on Unusual Marine Mammal Mortality

Events, which uses criteria for determining when an unusual mortality event is occurring and then

directs responses to such events. Once an event has been designated as “unusual,” the MMPA
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directs NMFS to inform the stranding network of that determination and to designate an onsite

coordinator. Once this has been done, there is a sequence of events that may take place, including

the following: stepped-up response to the event; increased monitoring and data collection; increased

communication with the National Stranding Network Coordinator; continued consultation with the

Working Group; increased collaboration with other groups and agencies; and enhanced monitoring

and data collection efforts. There have been 15 mortality events designated as “unusual” since 1990;

four occurring in the Gulf of Mexico (1990, 1992, 1993-1994, and 1996).

In recent years, high concentrations of potentially toxic substances in marine mammals have been

documented, both natural (e.g., biotoxins) and manmade (e.g., PCBs and pesticides). Harmful algal

blooms (HABs), which produce biotoxins, are of increasing interest as there have been new reports

of biotoxin related deaths in marine mammals. There seems to be an increased impact of these

events on marine mammals since 1972, but it is not clear whether this is truly the case or simply a

reflection of better reporting of stranding events. HABs have been implicated in strandings of

pinnipeds on the west coast of the United States, humpback whales in the northeastern United States,

manatees in Florida, and the Mediterranean monk seal in Mauritania. Relative to the Gulf of Mexico,

the most significant biotoxin relative to risks to marine mammals has been brevetoxin, and

considerable work still needs to be done to better assess the risk and to better detect the exposure,

levels and impacts in marine mammals.

The biomonitoring component of the MMHSRP was established to develop baseline health data,

monitor trends, and investigate impacts of disease, natural toxins, and pollution on marine mammal

populations. The biomonitoring component encompasses (1) biomonitoring; (2) case-specific

investigations; and (3) research and development. 

Biomonitoring in the Gulf of Mexico has principally been done through contaminant and health

studies at Mote Marine Laboratory, Dolphin Biological Research Institute, Southeast Fisheries

Science Center, and the Texas Marine Mammal Stranding Network. Through these programs

delphinids in the offshore northern Gulf were biopsied, bottlenose dolphins from Florida and Texas

strandings were monitored for contaminants and health, rough toothed dolphins from two mass

strandings were examined for health and contaminant levels, and live captures have been sampled

for organic pollutants, heavy metals and disease in two principal locations (Matagorda Bay and

Sarasota Bay). Analyses of tissues from delphinids in both coastal and pelagic areas show that all

the animals had been exposed to persistent organic pollutants and to heavy metals; however, there

are regional, species, and trophic level differences in the types and levels of pollutants. Future

studies will further address the potential risks of these exposures to marine mammal populations.

Future enhancements to the Southeast Region Stranding Network include the preparation of new

guidelines for the Letters of Authority (which grant the stranding networks the authority to respond

to stranding events), increased training, and a web-based or net-based stranding database. NMFS

has also been working to enhance coordination with international stranding networks in Latin

America, particularly with the Mexico stranding network, to better coordinate the greater Gulf of

Mexico area assessing stranding rates and health in species and individuals which may be shared

between the two countries. NMFS has scheduled stranding training workshops in various parts of

Latin America. NMFS is seeking matching funds to help with this coordination to attempt to close
108

the gap of stranding information for the Gulf of Mexico coastline extending from the Yucatan

Peninsula of Mexico to Brownsville, Texas.

Dr. Teri Rowles is with the NMFS Marine Mammal Health and Stranding Response Program. She

has been Program Coordinator since 1995.
109

NATIONAL OCEAN SERVICE AND SEA TURTLES:

HABITAT SUITABILITY MODELING

Mr. Michael S. Coyne

Biogeography Program

Center for Coastal Monitoring and Assessment

National Ocean Service

Silver Spring, Maryland

The objectives of this workshop are to (1) review the state of knowledge of marine species (marine

mammals and sea turtles) in the Gulf of Mexico protected under the Endangered Species Act and

Marine Mammal Protection Act; (2) identify critical information needs for the Minerals

Management Service (MMS); and (3) facilitate coordination among various funding agencies.

Within these guidelines, the emphasis of this paper is to review the National Ocean Services’ (NOS)

involvement in sea turtle research and, in particular, to describe the Biogeography Program’s

activities as they may help MMS meet the above objectives. Previous workshops have commented

on the need to develop a predictive model to quantitatively assess the impact of industrial activities

on sea turtle populations in the Northern Gulf (Bjorndal and Bolten 1990). Therefore, a large portion

of this paper describes the Biogeography Program’s expertise in habitat suitability modeling (HSM),

which offers an excellent opportunity for meeting this need.

NOS ACTIVITIES

Historically NOS has played a limited role in sea turtle research and management, although several

products have been used extensively by other state and federal agencies and departments. Earliest

efforts have included the development of such products as the Gulf of Mexico Coastal and Ocean

Zones Strategic Assessment: Data Atlas (NOAA 1985) which provided descriptions and

distributions of loggerhead and Kemp’s ridley sea turtles, as well as several marine mammal species.

More recent sea turtle work has been carried out within the National Marine Sanctuaries Program

of NOS. These efforts have primarily focused upon the loggerhead sea turtle and included tagging

and tracking of turtles that utilize Gray’s Reef off the coast of Georgia and the Flower Garden Banks

off the coast of Texas (Mitchell, in press).

Finally, the Center for Coastal Fisheries and Habitat Research in Beaufort, North Carolina, has

recently reorganized into the NOS organization. Previously a part of the National Marine Fisheries

Service (NMFS), the Beaufort laboratory has conducted and continues to carry out research in

cooperation with NMFS on sea turtles in the Pamlico-Albemarle Estuarine Complex. These efforts

have included work on juvenile loggerhead, green, and Kemp’s ridley sea turtles. Most notable is

an ongoing cooperative effort with local pound fishermen to establish an index-abundance-area to

monitor, assess and predict the status of and impacts to sea turtles and their ecosystems (Epperly et

al., in press). Additional work has involved the treatment and release of cold-stunned sea turtles and

the use of NOAA’s CoastWatch sea surface temperature (SST) imagery to help protect
110

Figure 29. Four approaches to coupling species distribution and habitat.

overwintering sea turtles during fishing activities off North Carolina and Virginia. A final rule under

the Endangered Species Act reduces the area within which Turtle Excluder Devices are required

during January 15 - March 15 (FR Vol. 61 Num. 16, pp1846-8). This imagery is being used by other

agencies and aquariums to help determine optimal locations along the east coast for returning

rehabilitated turtles to the sea.

BIOGEOGRAPHY PROGRAM ACTIVITIES

NOS’ Biogeography Program is part of the Center for Coastal Monitoring and Assessment within

the Centers for Coastal Ocean Science. Historically, the Biogeography Program has had little

involvement in sea turtle research or management activities. However, recent development of

cutting-edge GIS technologies and modeling techniques have placed the program in a position well

suited to address many issues related to protected species.

A goal of the Biogeography Program is to develop knowledge of living marine resource distributions

and ecology throughout the nation’s marine, coastal and estuarine environments to provide managers

with an improved ecosystem basis for making decisions. This effort has led to the development of

a suite of products which use a continuum of approaches to define bio-physical relationships which

differ in data content, complexity, and analytical structure (Figure 29). 

NOAA’s Biogeography Program was a partner with MMS in developing the Gulfwide Information

System (GWIS). The objective of GWIS was to develop an authoritative database to be used by

MMS, industry and other regulatory and resource protection agencies for oil spill planning and

response activities. Environmental sensitivity indices and biogeographic characterizations were

developed for invertebrate, fish, bird and sea turtle species. NOAA’s efforts included (1) digital

integration of NOAA’s Estuarine Living Marine Resources data (ELMR); (2) digital update of

selected coastal/marine fishes in the Gulf of Mexico; and (3) a development of a desktop GIS system

to organize and analyze the GWIS database.
111

NOAA’s Biogeography Program also has worked cooperatively with NMFS and the regional

Fishery Management Councils to meet Essential Fish Habitat requirements of the reauthorized

Magnuson-Stevens Fisheries Conservation and Management Act. Products delivered to the councils

included maps and supporting data with spatial and temporal distribution and abundance of

high-priority, managed species.

EFH work has helped identify critical information needs, particularly in the Caribbean, and has

catalyzed an effort to identify and map coral reef and other shallow water habitats in the Caribbean

using remote sensing technologies. A Memorandum of Understanding has been developed with the

National Park Service to utilize Buck Island National Monument (BUNM) in St. Croix as a test site

for the development of coral reef habitat classification scheme for Puerto Rico and the U.S. Virgin

Islands. Plans are currently under development to extend this effort to U.S. possessions in the

Pacific.

Specific habitat classification efforts at BUNM include a study of resident juvenile hawksbill sea

turtles in relation to distribution of prey. Zoanthids have been identified as a major dietary

component of BUNM hawksbills, and as such, the spatial and temporal distribution and abundance

of both organisms is being characterized. Additional cooperation with the NPS has led to advanced

GIS support for ongoing sea turtle satellite telemetry operations (Hillis-Starr et al., in press). New

approaches to spatial analysis of sea turtle tracking data are being developed beyond traditional

methods. Efforts are being made to explore new ways of displaying these data and to associate sea

turtle tracks with various habitat and environmental parameters.

HABITAT SUITABILITY MODELING

As a tool, habitat suitability modeling (HSM) has a lot to offer in terms of research and management

decision-making. The underlying approach was introduced by the U.S. Fish and Wildlife Service’s

Habitat Evaluation Procedures Program, whereby models resulted in a numerical index of habitat

suitability. Models were based on the assumption that a positive relationship exists between the

index and a habitat’s carrying capacity for a given species (Schamberger et al. 1982). Our models

depart from the USFWS methods by incorporating a spatial component to produce a view of the

relative suitability of locations in geographic space through time. The intent was to develop a simple

spatial model using GIS technology that offers estuarine resource managers a habitat assessment

capability that can be applied to a wide range of marine species.

Model complexity and structure can vary considerably depending upon data availability and the

questions being asked (Figure 30). The simplest models are based upon expert knowledge of a

species and its habitat to create simple polygonal maps of spatial and temporal distribution. Slightly

more complex models look at species distribution based upon a dominant environmental variable,

such as salinity (Bulger et al. 1993; Christensen et al. 1997). Habitat suitability index modeling

combines the suitability of several environmental variables using a simple equation, such as a
112

Figure 30. Hypothetical habitat suitability model for Kemp’s ridley sea turtles. Predicts potential

winter distribution.

geometric mean (Rubec et al. 1998; Rubec et al. 1999; Coyne et al., in press). Finally, several

habitat layers can be combined using a multivariate equation describing a species’ relationship to

those variables.

CONCLUSIONS

NOS’ Biogeography Program’s goal to develop knowledge of living marine resource distributions

and ecology coincide with MMS’ objectives as they relate to protected species. In particular, the

Biogeography Program’s experience with habitat suitability modeling can serve as an invaluable

tool. HSM is well-suited to address the need to develop predictive models to quantitatively assess

the impact of industrial activities on sea turtle populations in the Northern Gulf of Mexico.
113

REFERENCES

Bulger, A. J., B. P. Hayden, M. E. Monaco, D. M. Nelson and M. G. McCormick-Ray. 1993.

Biologically-based estuarine salinity zones derived from a multivariate analysis. Estuaries

16:311-22.

Bjorndal, K. A., and A. B. Bolten. 1990. Goals for sea turtle research in the Gulf of Mexico with

respect to the oil and gas industries. In Sea Turtles and Marine Mammals of the Gulf of Mexico,

Proceedings of a workshop help in New Orleans, August 1-3, 1989. OCS Study 90-0009. U.S.

Dept. of the Interior, Minerals Mgmt. Service, Gulf of Mexico OCS Regional Office, New

Orleans, LA. pp47-58.

Christensen, J. D., M. E. Monaco and T. A. Lowery. 1997. An index to assess the sensitivity of Gulf

of Mexico species to changes in estuarine salinity regimes. Gulf Research Reports 9:219-29.

Coyne, M. S., M. E. Monaco and A. M. Landry, Jr. In Press. Kemp’s ridley habitat suitability index

model. In Proceedings of the 18th International Sea Turtle Symposium, Mazatlan, Mexico.

Epperly, S. P., J. Braun-McNeill and A. L. Bass. In-water population index surveys: North Carolina,

USA. In Proceedings of the 18th International Sea Turtle Symposium, Mazatlan, Mexico.

Hillis-Starr, Z., M. Coyne and M. Monaco. In Press. Buck Island and back- hawksbill turtles make

their move. In Proceedings of the 19th Annual Symposium on Sea Turtle Conservation and

Biology, South Padre Island, Texas.

Mitchell, S. V. In press. Loggerhead sea turtle (Caretta caretta) satellite tagging project. In

Proceedings of the 18th International Sea Turtle Symposium, Mazatlan, Mexico.

National Oceanic and Atmospheric Administration. 1985. Gulf of Mexico Coastal and Ocean Zones

Strategic Assessment: Data Atlas. Strategic Assessment Branch, Ocean Assessments Division,

office of Oceanography and Marine Assessment, National Ocean Service and Southeast

Fisheries Center, National Marine Fisheries Service.

Rubec, P. J., J. C. W. Bexley, H. Norris, M. S. Coyne, M. E. Monaco, S. G. Smith and J. S. Ault.

1999. Suitability modeling to delineate habitat essential to sustainable fisheries. American

Fisheries Society Symposium 22:108-33.

Rubec, P. J., M. S. Coyne, R. H. McMichael, Jr., and M. E. Monaco. 1998. Spatial methods being

developed to determine essential fish habitat. Fisheries 23:21-5.

Schamberger, M., A. H. Farmer and J. W. Terrel. 1982. Habitat suitability index models:

Introduction. USFWS. FWS/OBS-82/10: 2pp.
114

Michael Coyne is a marine biologist with the National Ocean Service's Biogeography Program. He

received his graduate training from Texas A&M University studying feeding ecology in green sea

turtles and sex ratio and population dynamics of the Kemp's ridley sea turtle. Current responsibilities

include the development of distribution and abundance models for the nation's coastal ocean

resources, primarily utilizing GIS technology. He is also online coordinator for the internationally

distributed Marine Turtle Newsletter.
115

Southeast Fisheries Science Center

Sea Turtle Program

________________________________

• Recovery and Conservation Research

and Development

• Stock Assessment and Status Review

• Mortality Estimation

• Mortality (Bycatch) Reduction

• Habitat

• Health

 SEA TURTLES AND THE NATIONAL MARINE FISHERIES SERVICE

Ms. Sheryan Epperly

National Marine Fisheries Service

Ms. Epperly’s presentation included the following slides.
116

Recovery and Conservation Research

and Development

• ID/Distribution of Stocks

– mtDNA analysis of stranded loggerheads

and foraging ground animals (NMFS, Univ. of

Florida, & Florida DEP)

– nuclear DNA primer development,

description of Atlantic loggerhead rookeries,

and analysis of NC foraging ground animals

(Univ. of Florida)

– Caribbean hawksbill distribution and

movements (NMFS & Mexico, Caribbean nations)

Recovery and Conservation Research

and Development

• Population Trend Information

– Enhanced nesting surveys at Rancho Nuevo for

Kemp’s ridleys (USFWS, NMFS, Gladys Porter

Zoo, & Mexico)

– In-water index studies

• Pamlico-Albemarle Estuarine Complex, N.C.

(NMFS)

• s.e. U.S. (FY 2000) (NMFS & S.C.)

• St. Lucie, Fla. (Florida Power & Light Co.)

• Cedar Key, Fla. (NMFS & Univ. of Florida)
117

Recovery and Conservation Research

and Development

• Other Model Input Data

– Age Estimation (NMFS & Duke Univ. Marine

Lab)

– Mass tagging of hatchling Kemp’s ridleys to

estimate pelagic stage growth, duration, and

mortality (NMFS & Mexico)

– Cooperative Marine Turtle Tagging

Program (NMFS, Univ. of Florida, many states

and universities, observer programs, community

organizations, etc.)

Stock Assessment and Status Reviews

___________________________

• Turtle Expert Working Group (NMFS,

USFWS, Florida, Georgia, South Carolina, industry,

and CMC)

– Kemp’s ridley

– Loggerhead

• Sea Turtle Status Review Working

Group

– Kemp’s ridley

– Leatherback
118

Mortality Estimation

• Incidental Capture by Recreational

Fishermen (NMFS and the MRFSS: Gulf and

Atlantic Coast states & Texas)

• STSSN (all Atlantic Coast states, Univ. Alabama,

Gulf Islands National Seashore, Univ. Texas, Padre

Island National Seashore, McNeese State Univ.,

Aquarium of the Americas, and untold number of

volunteers)

• Commercial Fishery Observer Programs

– longlines, gillnets (Mid-Atl. coastal and shark

driftnet), trawlers in Mid-Atl. (flynets and

flounder trawls)

Mortality (By-Catch) Reduction

• TED Development (and observers) for

Shrimp, Flounder, and Flynet Trawls

(NMFS & industry)

• Captive Rearing for TED Testing (NMFS)

• Eastern Atlantic Longline Experiment

(NMFS, Univ. Florida, Azores, & industry)

• Monitoring AVHRR Imagery to Regulate

the Use of TEDs in the Winter Trawl

Fishery (NMFS & NOS’ CoastWatch)

• Platform Removal Surveys (NMFS & MMS)
119

Habitat

• In-Water Surveys for Green and

Hawksbill Turtles

– Puerto Rico (NMFS, P.R., USFWS, & Chelonia,

Inc.)

– U.S. Virgin Islands (FY2000?) (USVI, USFWS)

• Designation of Critical Habitat

– green turtles: Culebra, P.R.

– hawksbills: Mona and Monita Islands, P.R.

• South Florida Ecocystems

Health

• Health Assessment Workshops (NMFS, NOS

Charleston Lab, academia, private industry

veterinarians, etc.)

• Sea Turtle Anatomy Manual (Florida

Atlantic University)

• Sea Turtle Necropsy Manual (FY2000?)

• STSSN

• Fibropapilloma (lead is SWFSC; USFWS & many

academic collaborators)

• Forensics (NOS Charleston Lab & STSSN)
120

Sheryan Epperly completed her graduate work in fisheries (biochemical, meristic, and morphometric

identification of subpopulations of Atlantic menhaden) at the University of South Florida and Duke

University while employed as a student with the National Marine Fisheries Service. She worked for

the State of North Carolina for five years on estuarine and reef fish before returning to the NMFS

Beaufort Laboratory to work on ageing of juvenile Atlantic menhaden. She has numerous papers

published on her fisheries research. In 1988 she was assigned to begin a sea turtle research project

in North Carolina and since then has published seven peer review papers, seven non-peer reviewed

papers, and coauthored 23 presentations at scientific meetings on sea turtles. A year ago she moved

from Beaufort to the Southeast Fisheries Science Center in Miami where she is the team leader for

the Center’s Sea Turtle Program, coordinating research activities within and outside the agency.
121

U.S. GEOLOGICAL SURVEY/NATIONAL PARK SERVICE KEMP’S RIDLEY SEA

TURTLE RESEARCH AND MONITORING PROGRAMS IN TEXAS 

Dr. Donna J. Shaver

U.S. Geological Survey

Biological Resources Division

Columbia Environmental Research Center

Padre Island National Seashore

Over the last 20 years, the U.S. Geological Survey (USGS) and National Park Service (NPS) have

conducted many sea turtle research, monitoring, and conservation projects on the Texas coast. These

efforts have involved a variety of techniques for the five sea turtle species that occur in the

northwestern Gulf of Mexico. However, most work has focused on Kemp’s ridley (Lepidochelys

kempii), the most critically endangered sea turtle species in the world. 

EXPERIMENTAL IMPRINTING

For two decades, a project has been underway to increase Kemp’s ridley nesting at Padre Island

National Seashore (PAIS), Texas. Most Kemp’s ridley sea turtles nest near the village of Rancho

Nuevo, Tamaulipas, Mexico. In 1978, an experimental, bi-national project, involving the NPS,

National Marine Fisheries Service (NMFS), U.S. Fish and Wildlife Service (USFWS), Texas Parks

and Wildlife Department, and Mexico’s Instituto Nacional de la Pesca was undertaken to establish

a secondary nesting colony of Kemp’s ridley sea turtles at PAIS, where nesting had been

documented historically (Fletcher 1982; Shaver 1987, 1990, 1992). Establishing a secondary nesting

colony in the United States offered protection for the species, in case of an environmental or

political catastrophe at the primary nesting area in Mexico (Shaver 1990; USFWS and NMFS 1992).

From 1978 through 1988, approximately 2,000 Kemp’s ridley eggs were collected each year at

Rancho Nuevo and incubated at PAIS (Shaver 1990). Hatchlings were experimentally imprinted to

the beach at PAIS in hopes that they would someday return to south Texas to nest. Each year, turtles

from this project were reared in captivity for their first 9-11 months of life (head-started), tagged,

and released into the Gulf of Mexico and adjacent bays (Caillouet et al. 1995). 

NEST DETECTION AND EGG INCUBATION

Systematic patrols to detect sea turtle nesting on North Padre Island began in 1986, with increasing

patrol efforts each subsequent year. Each summer, NPS staff members, USGS staff members, and

volunteers search 125 km of Gulf of Mexico beach front on North Padre Island (including the 105

km length of PAIS) via all-terrain-vehicles. When located, nesting turtles are examined for existing

tags and any unmarked turtles are tagged. However, in many instances this is not possible because

the turtles re-enter the water before staff arrive. Eggs from virtually all Kemp’s ridley and other

sea turtle nests detected on the Texas coast are transferred to the Padre Island National Seashore

incubation facility for protected care; emerging hatchlings are released at PAIS (Shaver 1990,

1997). 
122

During the last 50 years (1948-1998), more confirmed Kemp’s ridley nests were located at PAIS

than at anywhere else in the U.S. (Shaver and Caillouet 1998). During this time, 45 Kemp’s ridley

nests were documented on the Texas coast. All 45 confirmed nests were found in south Texas, with

28 documented at PAIS. Thirty-two of the 45 nests occurred between 1995-1998, with numbers

increasing during each of those four consecutive years. The recent increase in detected nesting may

reflect increased nesting, improved patrol and nest location efforts, increased awareness and

reporting by the public, or a combination of all of these factors. 

Six of the 32 confirmed Kemp’s ridley nests found on the Texas coast from 1995-1998 were

conclusively linked to five turtles from the experimental imprinting project (Shaver 1996a, 1996b,

1997; Shaver and Caillouet 1998). The Kemp’s ridleys currently nesting in south Texas are probably

a mixture of both returnees and turtles from the wild stock, with some individuals nesting both in

Mexico and south Texas. The Kemp’s ridley population is increasing (USFWS and NMFS 1992;

TEWG 1998) and as the population continues to increase and more turtles from the experimental

project mature, nesting in south Texas will likely increase. Given the potential for recovery of this

species, it is important to ensure their protection at the nesting beaches and in the marine

environment.

SEA TURTLE STRANDING AND SALVAGE NETWORK

Sea turtles that strand (wash ashore, alive or dead) in the United States are documented by the Sea

Turtle Stranding and Salvage Network (STSSN), which was established in 1980. Live turtles are

taken to rehabilitation facilities and dead turtles are often salvaged for necropsy and study. At PAIS,

turtles found stranded in Texas are tallied and their attributes are studied.

Although adult Kemp’s ridleys forage in, and migrate through, near shore waters of several coastal

states, more adult Kemp’s ridleys have been documented stranded in Texas than in any other state

of the United States (Shaver in press). From 1995-1998, when increased Kemp’s ridley nesting was

detected on the Texas coast, 76 adult Kemp’s ridleys were documented stranded on Gulf of Mexico

beaches in south Texas; all 76 were found dead and about half of these occurred at PAIS. Seventyfive of the 76 were found at times when Gulf waters were open to shrimp trawling. Much of this

mortality occurred during the Kemp’s ridley mating and nesting seasons and the deaths of adult

Kemp’s ridleys in south Texas waters during this critical time in their life cycle could adversely

impact efforts to establish a secondary nesting colony there (Shaver in press). 

SATELLITE TRACKING

Since 1997, satellite transmitters have been attached to a few Kemp’s ridleys that nested in south

Texas, to identify nesting sites, study movement patterns, and delineate areas of vulnerability to

various threats in the marine environment. Two transmitters were deployed during 1997 and four

during 1998. After completion of egg laying for the year, all six turtles traveled northward and spent

the majority of their time in Gulf of Mexico waters off Louisiana and the west coast of Florida.

These investigations documenting movement patterns and habitat preferences of Kemp’s ridley sea

turtles can provide a scientific basis for future management and policy decisions concerning the

protection and restoration of this species. 
123

REFERENCES

Caillouet, C.W., Jr., C.T. Fontaine, S.A. Manzella-Tirpak, and D.J. Shaver. 1995. Survival of headstarted Kemp’s ridley sea turtles (Lepidochelys kempii) released into the Gulf of Mexico or

adjacent bays. Chelonian Conservation and Biology 1(4):285-292.

Fletcher, M.R. 1982. Atlantic ridley turtle reintroduced at Padre Island. Park Science 2(2):3-4

Shaver, D.J. In press. Kemp’s Ridley Sea Turtle Project at Padre Island National Seashore, Texas.

In University of New Orleans (Compiler). Proceedings: Seventeenth Annual Gulf of Mexico

Information Transfer Meeting. Minerals Mgmt. Service, Gulf of Mexico OCS Region. 

Shaver, D.J. 1987. Padre Island Kemp’s Ridley Sea Turtle Project update. Park Science 7(4):8-9.

Shaver, D.J. 1990. Kemp’s Ridley Project at Padre Island enters a new phase. Park Science 10:12-

13.

Shaver, D.J. 1992. Kemp’s ridley research continues at Padre Island National Seashore. Park

Science 12(4):26-27.

Shaver, D.J. 1996a. Head-started Kemp’s ridley turtles nest in Texas. Marine Turtle Newsletter

74:5-7.

Shaver, D.J. 1996b. A note about Kemp’s ridley nesting in Texas. Marine Turtle Newsletter 75:25.

Shaver, D.J. 1997. Kemp’s ridley turtles from international project return to Texas to nest. In

University of New Orleans (compiler). Pages 38-40 in Proceedings of the Sixteenth Annual Gulf

of Mexico Information Transfer Meeting. Minerals Mgmt. Service, Gulf of Mexico OCS

Region, MMS 97-0038. 

Shaver, D.J., and C.W. Caillouet, Jr. 1998. More Kemp’s ridley turtles return to south Texas to nest.

Marine Turtle Newsletter 82:1-5.

TEWG (Turtle Expert Working Group). 1998. An assessment of the Kemp’s ridley (Lepidochelys

kempii) and loggerhead (Caretta caretta) sea turtle populations in the western North Atlantic.

NOAA Technical Memorandum NMFS-SEFSC-409. 96 pp.

U.S. Fish and Wildlife Service and National Marine Fisheries Service. 1992. Recovery plan for the

Kemp’s ridley sea turtle (Lepidochelys kempii). National Marine Fisheries Service. St.

Petersburg, Florida. 40 pp.
124

Dr. Donna J. Shaver is an employee of the U.S. Geological Survey, Biological Resources Division,

and is the Station Leader of the Padre Island Field Station, located at Padre Island National

Seashore. She has been involved in sea turtle work for the last 19 years. Dr. Shaver oversees a

variety of sea turtle research and conservation projects conducted at Padre Island National Seashore

and is the Texas Coordinator for the Sea Turtle Stranding and Salvage Network. She received her

B.S. in wildlife biology from Cornell University, her M.S. in biology from Texas A&I University,

and her Ph.D. zoology at Texas A&M University.
125

PROTECTING SEA TURTLES DURING DREDGING BY

THE U.S. ARMY CORPS OF ENGINEERS

Dr. David A. Nelson

USAE Waterways Experiment Station

Vicksburg, Mississippi

Sea turtles are distributed in the Gulf of Mexico from Texas to Florida and in the Atlantic Ocean

from Florida to Nova Scotia (Hildebrand 1982; Hopkins and Richardson 1984; Lee and Palmer

1981; Nelson 1988; Rebel 1974). On the east coast of the United States, loggerhead turtles are found

in inshore waters of Rhode Island (Keinath 1986), New York (Burke 1990; Burke and Standora

1991; Morreale et al. 1992), Virginia (Byles 1988; Keinath 1993; Lutcavage and Musick 1985;

Musick 1979), North Carolina (Epperly et al. 1995; Keinath et al. 1992; Keinath 1993; Shoop and

Kenney 1992), South Carolina (Van Dolah and Maier 1993), Georgia (Stoneburner 1982), and

Florida (Bolton et al. 1994; Butler et al. 1987; Mendonca and Ehrhart 1982). 

Except when the adult females come ashore to nest, sea turtles generally occur singularly and move

over large areas in coastal marine waters. This solitary, wide-ranging behavior insures that studies

of these animals are difficult, time consuming, and expensive. However, studies on sea turtle

behavior in aquatic habitats are important not only to increase our knowledge of this part of their

life cycle but to assess the causes and to prevent impacts of human activities on these species

(National Research Council 1990; Thompson et al. 1990). This is particularly true in near-shore and

entrance channel aquatic habitats where the primary causes of sea turtle injury and mortality are

channel dredging, shrimping, recreational fishing, and boat traffic (National Research Council 1990;

Renaud et al. 1995; Slay and Richardson 1988). To reduce impacts from these human activities, and

to help management make informed Resource decisions, behavior information has been critically

needed. Resource managers need specific behavior data such as surface durations, submergence

durations (breath holding), and bottom durations to calculate population estimates accurately. Such

data are also required to limit bottom trawling time by commercial fishermen and to design methods

to prevent entrainment by channel dredgers. However, aquatic behavior research on sea turtles has

been limited to a few animals in a limited number of geographic locations.

The U.S. Army Corps of Engineers initiated studies to fill the void in our knowledge of sea turtle

activities in near-shore and navigation channel environs and to determine methods to minimize sea

turtle entrainment by hopper dredges. On the east coast of the United States, studies were conducted

in Charleston Harbor entrance channel, South Carolina (Keinath et al. 1995); Savannah entrance

channel, Georgia (Keinath et al. 1995); St. Marys entrance channel, Georgia (Nelson 1996); and

Canaveral entrance channel, Florida (Standora et al. 1993). On the Gulf Coast, studies were

conducted in Tampa Bay entrance channel (Nelson in preparation). The focus of the research was

to identify and compare seasonal sea turtle vertical movements within the water column, in addition

to comparing horizontal movements relative to the entrance channel seasonally. Relative abundance

surveys were conducted with trawlers to determine the times of least sea turtle abundance. Behavior

studies were conducted using radio and sonic telemetry to determine diving activities and local
126

movement patterns. In addition, satellite telemetry was used to determine large-scale seasonal

movement patterns.

As a result of these studies, several measures to prevent the entrainment of sea turtles during

dredging have been made available to dredging managers. These include restricting dredging to the

seasons with colder water when turtles are least abundant, sequencing of dredging from channels

with the most turtles to channels with the least, installation of deflector dragheads and relocation of

turtles out of the channel during dredging. Since none of these measures is 100 % effective for all

situations, each measure individually and in combination is being implemented by the US Army

Corps of Engineers to manage their dredging. Restricting dredging to the winter season when water

temperatures are coldest and less suitable for sea turtles has proven to be very effective. However,

this restriction is no longer effective when dredging must be scheduled outside this window or when

water temperatures become unseasonably warm within the window (as in 1999) (Nelson 1999).

Sequencing dredging to dredge channels with higher densities of turtles during the colder months

is also very effective; however, not all channels can be dredged during the three- or four-month

winter season. The deflector draghead works well in soft sediments. However, when the sea floor

is uneven the draghead can not maintain contact with the bottom. In such situations, turtles are

exposed to the intake on the draghead. The effectiveness of relocation trawling has been debated

because it is difficult to evaluate. Sea turtles have been taken by the dredge even though relocation

trawling was underway. Turtles can not be completely excluded from the channel by the trawling

since they are constantly moving in and out of the channel and may return to the channel area after

relocation. Even though not all turtles are captured and removed from the channel by the relocation

trawling, no relocated turtle has ever been observed as part of the dredge take. If a relocated turtle

were entrained, it would be identified by a flipper tag and/or an internal pit tag installed on all

relocated turtles.

Results from these studies have allowed the US Army Corps of Engineers to reduce the entrainment

of sea turtles by an estimated 95-99 %.

REFERENCES

Bolten, A. B., K. A. Bjorndal, P. J. Eliazar and L. F. Gregory, L. F. 1994. Seasonal abundance, size

distribution, and blood biochemical values of loggerheads (Caretta caretta) in Port Canaveral

Ship Channel, Florida. NOAA Technical Memorandum NMFS-SEFC-353, National Marine

Fisheries Service, Miami, FL. 39 pp.

Burke, V. J. 1990. Seasonal ecology of Kemp’s ridley (Lepidochelys kempi) and loggerhead

(Caretta caretta) sea turtles in the waters of Long Island, New York. Unpublished MS thesis.

State University of New York, College at Buffalo, New York. 91 pp.

Burke, V. J. and E. A. Standora. 1991. Factors affecting strandings of cold-stunned juvenile Kemp’s

ridley and loggerhead sea turtles in Long Island, New York. Copeia 1991(4):1136-1138.
127

Butler, R. W., W. A. Nelson and T. A. Henwood. 1987. A trawl survey method for estimating

loggerhead turtle, (Caretta caretta), abundance in five eastern Florida channels and inlets.

Fishery Bulletin 85(3):447-453.

Byles, R. A. and J. A. Keinath. 1990. Satellite monitoring sea turtles. pp. 73-75. In T. H.

Richardson, J. I. Richardson and M. Donnelly (compilers). Proceedings of the tenth annual

workshop on sea turtle conservation and biology, February, 1990, Hilton Head, South Carolina.

NOAA Technical Memorandum NMFS-SEFC-278. 286 pp. 

Epperly, S. P. , J. Braun, A. J. Chester, F. A. Cross, J. V. Merriner and P. A. Tester. 1995a. Winter

distribution of sea turtles in the vicinity of Cape Hatteras and their interactions with the summer

flounder trawl fishery. Bulletin of Marine Science 56(2):547-568.

Hildebrand, H. H. 1982. A historical review of the status of sea turtle populations in the western

Gulf of Mexico. pp.447-453. In K. A. Bjorndal, ed. Biology and conservation of sea turtles.

Smithsonian Institution Press, Washington, D. C. 

Hopkins, S. R. and J. I. Richardson, eds. 1984. Recovery plan for marine turtles. U. S. Department

of Commerce, NOAA, NMFS, St Petersburg, FL 355 pp.

Keinath, J. A. 1986. A telemetric study of the surface and submersion activities of Dermochelys

coriacea and Caretta caretta. MS Thesis. University of Rhode Island, Kingston, R.I. 85 pp.

Keinath, J. A., D. E. Barnard and J. A. Musick. 1995. Behavior of loggerhead sea turtles in

Savannah, Georgia and Charleston, South Carolina shipping channels. Final contract report

DACW39-93-C-0016 to U. S. A. E. Waterways Experiment Station, Vicksburg, MS. 75 pp.

Keinath, J. A., J. A. Musick, and D. E. Barnard. 1992. Abundance and distribution of sea turtles off

North Carolina. U. S. Department of Interior, Minerals Management Service. OCS Study, final

draft report. 99 pp.

Keinath, J. A. and J. A. Musick. 1993. Movements and diving behavior of a leatherback turtle,

Dermochelys coriacea. Copeia 1993(4):1010-1017.

Lee, D. S. And W. M. Palmer. 1981. Records of leatherback turtles, Dermochelys coriacea

(Linnaeus), and other marine turtles in North Carolina waters. Brimleyana 5:95-106.

Lutcavage, M. E. and J. A. Musick. 1985. Aspects of the biology of sea turtles in Virginia. Copeia

1985(2):449-456.

Mendonca, M. T. and L. M. Ehrhart. 1982. Activity, population size and structure of immature

Chelonia mydas in Mosquito Lagoon, Florida. Copeia 1982(1):161-167.

Morreale, S. J. , A. B. Meylan, S. S. Sadove and E. A. Standora. 1992. Annual occurrence and

winter mortality of marine turtles in New York waters. Journal of Herpetology 26(2):310-308.
128

Musick, J. A. 1979. The marine turtles of Virginia with notes on identification and natural history.

Virginia Institute of Marine Science, School of Marine Science, College of William and Mary.

Educational Series Number 24. 17 pp.

Musick, J. A., R. Byles, R. Klinger and S. Bellmund. 1985. Mortality and behavior of sea turtle in

the Chesapeake Bay. Summary Report for 1979-1983. Submitted to the National Marine

Fisheries Service. VIMS, College of William and Mary. Gloucester Pt., VA. 52 pp.

National Research Council. 1990. Decline of the sea turtles: Causes and prevention. National

Academy Press, Washington, D. C. 259 pp.

Nelson, D. A. 1988. Life history and environmental requirements of loggerhead turtles. U. S.

Department of Interior Biological Report 88(23). 34 pp.

Nelson, D. A. 1996. Subadult loggerhead sea turtle (caretta caretta) behavior in St Marys entrance

channel, Georgia, USA. PhD Disertation, College of William and Mary, Virginia Institute of

Marine Science.

Nelson, D. A. 1999. Relocation of Sea Turtles During Dredging Operations in the Brunswick

Entrance Channel, Ga. Contract report to the US Army Engineer District, Savannah, prepared

by the USAE Waterways Experiment Station, Vicksburg, MS.

Nelson, D. A., C. Dickerson, K. Reine and D. Dickerson. 1993. Assessment of sea turtle relative

abundance in Kings Bay entrance channel, GA. U. S. Army Engineer Waterways Experiment

Station draft report prepared for the U. S. Army Engineer Division, South Atlantic. 60 pp.

Nelson, D. A. and D. J. Shafer. 1995. Test of sea turtle-deflecting hopper dredge draghead in

Canaveral entrance channel, Florida. U. S. Army Engineer Waterways Experiment Station draft

report prepared for the U. S. Army Engineer District, Jacksonville . 33 pp.

Renaud, M. L., J. A. Carpenter, J. A. Williams and S. A. Manzella-Terpak. 1995. Activities of

juvenile green turtles, Chelonia mydas, at a jettied pass in south Texas. Fishery Bull. 93:586-593

(1995).

Rebel, T. J., ed. 1974. Sea turtles and the turtle industry of the West Indies, Florida and the Gulf of

Mexico. University of Miami Press, Coral Gables, FL. 250 pp.

Shoop, C. R. and R. D. Kenney. 1992. Seasonal distributions and abundances of loggerhead and

leatherback sea turtles in water of the northeastern United States. Herpetological Monographs

6:43-67.

Slay, C. K. and J. L. Richardson. 1988. King’s Bay, Georgia: dredging and turtles. pp. 109-111. In

B. A. Schroeder (compiler). Proceedings of the 10th annual workshop on sea turtle biology and

conservation. NOAA Technical Memorandum NMFS-SEFC-214, 136 pp.
129

Standora, E. A., S. J. Morreale and A. Bolten. 1993. Diving behavior, daily movements, and homing

of loggerhead turtles (Caretta caretta) at Cape Canaveral, Florida, March and April 1993.

Contract Project Report prepared for U.S. Army Engineer Waterways Experiment Station,

Vicksburg, MS.

Stoneburner, D. L. 1982. Satellite telemetry of loggerhead sea turtle movement in the Georgia Bight.

Copeia 1982:400-408.

Thompson, N., T. Henwood, S. Epperly, R. Lohoefener, G. Gitschlag, L. Ogren, J. Mysing and M.

Renaud. 1990. Marine turtle habitat plan. U. S. Department of Commerce, NOAA Technical

Memorandum NMFS-SEFC-255. 20 pp.

Van Dolah, R. F. and P. P. Maier. 1993. The distribution of loggerhead turtles (Caretta caretta) in

the entrance channel of Charleston Harbor, South Carolina, U.S.A. Journal of Coastal Research

9(4):1004-1012.
130

THE NAVY AND MARINE MAMMAL CONCERNS THAT

CAN APPLY TO THE GULF OF MEXICO

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.l00/n45/branch/n454/.). In order to foster better understanding of the

potential effects from sound and to develop the means to better assess and mitigate such effects, the

Office of Naval Research (ONR) has initiated research. We 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 also be useful to other federal, state and local agencies, to relevant industry and

other non-government parties, and to the overall public interest. While the Navy has relatively few

activities in the Gulf of Mexico (GOM), it recognizes that research involving commonly used sound

sources may have applicability to issues in the GOM faced by the Minerals Management Service

and other public and private organizations.

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 keep in mind that the two processes are independent; therefore, one should not draw

premature conclusions from this presentation about implications for Navy or national policy,

guidelines or regulations. In some cases I will describe experimental designs that have not yet

produced data. In other cases I describe work so recently completed that there has not been 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 discuss, 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 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.

SOME 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,
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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

and Nobel prizes as it is about delivering new technology to the Navy. As you will see, the ONR

research program into the effects of underwater sound on marine organisms takes 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 is usually published in scientific journals or other publically

accessible sources under academic peer review.

RATIONALE FOR THE ONR PROGRAM

Lethal and injurious effects from shock waves and sound overpressure or energy flux are well

documented and need not be discussed in detail here (see Yelverton 1981; Young 1991; Ketten

1995). Larger animals are likely to withstand greater peak pressures than smaller animals. Keep in

mind that these are received values; source levels might be much higher, depending on the range

from the source. Also, these are very sudden sharp pressure changes associated with impulse events;

equivalent peak pressures in tonal sounds would be less likely to induce damage due to the slower

acceleration of tissues by the slower, smoother pressure changes in tonal sounds, with the possible

exception of resonant frequencies that can result in damage from recurring oscillations of the

resonating space, e.g. resonance of the lungs leading to tissue damage.

Determination of physiological effects from non-impulse sound is less well studied. ONR is

currently co-sponsoring research with human divers and terrestrial animal models (mice, rats, guinea

pigs and pigs) to determine behavioral and injurious thresholds for low frequency tonal sounds

between 100 and 2500 Hz. What few results we have in this new program are not ready for reporting

at this meeting but will become available over the course of the year through peer-reviewed

scientific publications by the researchers and other public-release reports. As might be expected, it

is unlikely that we will see a proposal containing a legally and ethically acceptable technique to test

live marine mammals with potentially damaging levels of noise. We will therefore probably be

forced to extrapolate from terrestrial animal models, with the attendant uncertainties that arise from

physiological differences between terrestrial mammals and marine mammals. At present, the lowest

clear and reproducible damaging effect in terrestrial animals (rats and mice) comes from resonance

of gas-filled spaces such as the lung, with onset of injurious effects after a few minutes exposure at

around 180 dB re 1 microPascal (received SPL) at the resonant frequency, and at 190+ dB at

nonresonant frequencies just a few Hz to either side of the resonant frequency. Since the lung

resonant frequency of humans and therefore almost all marine mammals is lower than 45 Hz

(slightly higher at depth), most impulse sources and all existing and planned LF sonar sources will

be too high frequency to excite lung resonance. We are still looking at possible harmonic resonance
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frequencies, resonance frequencies of sub-spaces such as single alveoli or bronchioles, and

resonance of other smaller gas-filled spaces such as in the gastro-intestinal tract that might fall

within the frequency range between 100 and 3,000 Hz. Other suspected effects, such as vestibular

effects (vertigo, nystagmus, etc.), disruptions of cardiac rhythms, or effects on central or peripheral

nervous tissues have not been found, but work is still ongoing.

At the other end of the spectrum are noninjurious behavioral responses. 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.

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 that bridge the region between injurious effects and more variable, less predictable behavioral

responses.

TEMPORARY THRESHOLD SHIFT (ITS)

This study is being carried out under the leadership of Dr. Sam Ridgway at the Space and Naval

Warfare Systems Center (SSC) 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 employed 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. Sound pressure levels at the limit of the device’s capability (220 dB peak-to-peak, or 170

dB RMS) failed to induce TTS, so we are seeking impulse sound sources capable of producing

higher energies. We are currently seeking other impulse sources such as airguns and sparkers, and

would appreciate any assistance MMS and industry could give us in obtaining an impulse sound

source that could be used in a safe stairstep methodology for assessing ITS. Other planned work
133

with tonal and impulse sounds includes establishing the scaling relationship between repetitive

sound or duty cycle and recovery from ITS, effects of signal duration on ITS, and contribution of

masking or background noise to the observed TTS effect.

The onset of temporary threshold shift to short (one second) tonal signals at frequencies between

400 Hz and 70 kHz has been on the order of 190-200 dB. We anticipate that responses to shorter

duration impulse events will be at similar signal strengths, but that is a question 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, ITS 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 ITS 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

californianus), bottlenose dolphins (Tursiops truncatus), and beluga or white whales

(Delphinapteras 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. 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 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 ITS event. Animals must return to full pre-test levels before they

are allowed to do another ITS test. Up-to-date results from these three parallel independent studies

will be presented at the Acoustical Society of America meeting in Columbus Ohio in October 1999.

ONR anticipates a lot of interest not only in the presentations, but in the discussion among

presenters and audience members due to the potential significance of these data to our understanding

of how marine mammal ears respond to underwater noise and the potential regulatory implications

of such data.

ITS is of interest for two reasons. First, it bears some relationship to Permanent Threshold Shift

(PIS). Though the causal relationship is not clear, it appears that repeated ITS events can lead to

PTS, and onset of ITS bears a fairly consistent relationship to onset of PIS (generally, PIS occurs

about ten decibels above ITS, though this can vary) (Kryter 1985; Ward 1991). Since it is

undesirable to deliberately induce PIS to determine the actual onset of permanent hearing damage,

testing for ITS at least gives us a “ballpark” number from which to estimate a general sound level

at which PIS may be likely. Second, ITS means that an individual is temporarily deprived of a
134

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 ITS effects thus permits more reliable and precise risk assessments about the

effects of a given sound source with the potential to cause ITS.

MEASUREMENT OF MACRO AND MICRO SCALE

DAMAGE FROM IMPULSE EVENTS

Since it would be 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. According to Dr. Darlene Ketten of Woods Hole Oceanographic Institution and the

Harvard Medical School, even microscopic structures such as the cilia on inner ear hair cells retain

their structural mechanical properties for a considerable period post mortem. Thus, they may 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 effects are restricted to such microscopic effects as damage to hair

cells, with no other obvious injury.

Dr. Ketten will use special techniques that she developed for high resolution x-ray computed

tomopgraphic 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 provides

a schematic illustration of the sequence of experimental procedures. Sound output from explosives

scales with charge size (Kibblewhite & Denham 1970), 50 small charges contained 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), 50 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, such

as exists for human in-air auditory damage from guns and explosions (Price & KaIb 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.
135

CONTROLLED EXPOSURE STUDIES

Beginning with the ATOC Marine Mammal Research Program in 1994 the scientific community

has shown a growing ability to perform complex integrated biological studies at sea to monitor the

effects of a sound source on large (hundreds of square miles) zones of potential effect. Initially,

monitoring of sound sources was largely limited to aerial and shipboard visual surveys for surfaced

animals, but increasingly complex data sets are being gathered by the integration of multiple passive

acoustic monitoring tools (sonabuoys, bottom-mounted arrays, towed arrays, vertical arrays) and

attachable dataloggers for recording the movements of the animals and the ambient conditions

through which they pass. Most recently, these data have been merged with complex 3-D sound field

modeling, physical and chemical oceanographic data from ships, satellites and buoys, and prey field

mapping with high-frequency acoustics and net tows. When these data are assembled, they provide

very sensitive and powerful statistical estimates of behavioral response to sound that are not

confounded by animal response to food, conspecifics or physical changes to the environment, as was

the case in earlier pioneer work with ATOC and some industrial noise sources. The data also

provide unprecedented insights into the animal’s three-dimensional underwater world and its

interaction with that environment through underwater movements, vocalizations and other behavior

previously unaccessible to the surface-based marine mammal scientist. The LFA sonar Scientific

Research Program, co-sponsored by ONR and other branches of the Navy reflects the current stateof-the-art in multi-methods monitoring with a controllable sound source. Reporting of data from that

program is expected to continue throughout the coming year, including release of the LFA EIS some

time later this summer (exact date is not yet known).

ONR plans to continue similar controlled noise exposure studies with sound sources and marine

mammal species or localities of greatest interest to the community at large. At present,

Mediterranean deep divers (sperm whales and Cuvier’s beaked whales) and north Atlantic right

whales are among the species and localities of greatest interest. ONR is working with Navy and nonNavy potential partners to put together multi-disciplinary studies of the biology and response to

noise of these species. As further data come in from the ITS, human diver safety, and other

programs, we expect to have even more confidence in our ability to introduce safe levels of sound

and ramp up in a carefully controlled manner to thresholds of behavioral aversion without risk of

injurious or serious and widespread behavioral effects. Key to such a process will be the inclusion

of international, national, state and local entities as well as concerned citizens’ organizations and

professional peers in a process of oversight both in the planning of the controlled exposure study

and in the review of work in progress and final reports.

CONCLUSION

The types of experiments described above should provide a detailed and statistically strong 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’s and Ridgway’s data
136

Marine Mammal

Investigations by the U.S.

Navy That Can Apply to the

Gulf of Mexico

A presentation to the MMS Marine Protected

Species Workshop

15-16 June 1999

Dr. Robert C. Gisiner, Office of Naval Research

should support predictive math models that can be used to extend their results to impulse and tonal

sources of different types, and the models should scale in predictable ways for animals of different

size.

These experiments, which should be completed within the next two years, should 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 well-being, and

if so what kinds of efforts and what level of support will be required to resolve these remaining

questions.

The slide show that accompanied this presentation follows.
137

The Issue

• Manmade underwater sound is increasing

– due to increased shipping and industrial activity

– due to increased importance for military activities

– due to increased use for research and exploration

• There is potential for harmful effect

– lethal or injurious effects of high energy sources

– disruptive effects on sensing and behavior

• The law requires us to assess and minimize

impact

– Marine Mammal Protection Act, Endangered Species Act

– for government in particular: NEPA, EO 12114

The Navy Response

• A large ONR research program,

• linked with efforts by CNO N45 and technology

acquisition program offices,

• coordinated by the Office of the Secretary of the

Navy, plus

• monitoring and mitigation programs for Navy

acquisition programs (e.g. ship shock testing and

LF sonar tests) will also be used as data sources

• data dissemination to NATO, other federal

agencies, public.
138

What information do you

need to assess risk?

• Characteristics of all sound sources:

– including pingers, modems, calibration signals, etc.

– fully characterized: duration, duty cycle, source level,

waveform or time/freq display, directionality, etc.

• Area ensonified

– sometimes simple models of spherical or cylindrical

spreading will do, but most often a PE or other

complex model is best.

• Who’s there?

• What is their likely response to the sound?

Who’s There?

• The Navy, in collaboration with NOAA, is

developing abundance and distribution databases

– they enable quick preliminary assessments of risk

– they are probably the easiest and biggest impact

mitigation tool you can get.

• A preliminary version, Living Marine Resources

Information System, developed as a tool for Navy

planners and ship operators, is going into fleet

use within the next 1-2 years

– Added tool, such as the Acoustic Integration Models

are in development
139

LMR Occurrence Displays

Gray Whale, January Gray Whale, February

N. Right Whale, January Blue Whale, August

T L Prediction, N avy PE M odel

A T L “slice” show ing sign al in ten sity at 90 fe et in de pth

is p lotte d g iven a m id-w ater colum n lo cate d so urce in an “a cou stically

shallo w ” reg ion .
140

AIM

MODEL

150-200m

feeding 

zone

3 min at surface

breathing

7 min at depth

feeding

Krill

Surface

0 to 3 kts

net fwd

motion

II

II

III

II

II

II

II

III

deep

shelf

III

Humpback Whale

(May-October)

_______________

II .0001-.02/km2

III .02-.04/km2

III .04-.11/km2

Humpback Whale

(May-October)

_______________

II .0001-.02/km2

III .02-.04/km2

III .04-.11/km2

Typical Marine Mammal

Distribution Data Base Format

Example: OCS MMS89-0030,1990

Typical Marine Mammal

Distribution Data Base Format

Example: OCS MMS89-0030,1990

Lat

Lon

Depth 

Contours

Diving Behavior

Distribution

CDF of Received Levels

50

100

100 140 180

RL (dB)

Percent

0

3000m

200m

LON

LAT

Depth

Range

TL

Source

III

Source &

Animal Tracks

Net Sound

Exposure

What’s the likely response?

• Lethal and injurious effects:

– human diver and laboratory animal studies suggest onset in the

180-200 dB range for LF tonal sounds

– impulse effects studies with dead specimens from stranding

networks

– is Temporary Threshold shift the “highest safe” measurement for

auditory specialists?

• Behavioral Effects

– direct observations in lab and field settings

– hearing data: “if it is audible it is potentially able to affect

behavior.”

• Chronic sub-threshold effects

– effects of repeated or prolonged exposure that produces no

obvious reaction
141

Rochester: DRT for Lung

Hemorrhage

• DRT for mice at RF (mean 328 Hz), 300 and 350 Hz:

dB SPL Freq Damage

 184.1 RF lung hemorrhage

 184.6 RF liver hemorrhage

 189 RF air in chest

 190.5 RF air in abdomen

 186.5 300 Hz lung hemorrhage

 188.8 300 Hz liver hemorrhage

 188.0 350 Hz lung hemorrhage

 188.8 350 Hz liver hemorrhage

• No significant damage occurred at maximal SPL of the G40 for

animals exposed to 100, 250, 400 and 500 Hz.

Marine Mammal Blast and Acoustic Trauma Measures

Ketten, D.R./Harvard Medical School/WHOI

strandings

screening

testing

necropsy

modeling

microscopy
142

Threshold (dB re 1 μPa)

Frequency (kHz)

20

30

40

50

60

70

80

90

100

110

120

130

140

1 10 3 4 5 6 25 50 70

T ursiop s (Jo hnson, 196 7)

2 7 200 100

T ursiop s left p anb one (1997 )

T ursiop s right panbone (199 7)

T ursiop s left p anb one (1991 )

T ursiop s right panbone (199 1)

T ursiop s right panbone (199 7)

T ursiop s left p anb one (1997 )

Tursiops truncatus Hearing Thresholds

40 d B sloping loss at 50 kHz

30 kHz “notch”

Tursiops

Functional M odel 

Frequency Map

162760 Hz 

2.6 mm

121810 

5.1

89694

7.8

65955

10.4

48408

13 35437

15.6

30281

16.9

22038

19.6

15945

22.2

9651

26.1

6789

28.9

4673

31.4

2487

35.3

1494

37.9

759

40.1

467

41.2

216

41.8

104

42.5

k=0.88

42.5 mm

cochlea

Dr. Darlene Ketten

Woods Hole, O.I.; Harvard Medical School

“Predicting Hearing from Anatomy”

•Employs hi-res CT scanning & std.

Histology to get 3-D anatomy of ear

•Applies biomechanical models &

neurophysiology to predict performance.

•Verifies predicted performance with

behavioral calibration.

•Has provided the ONLY data on

hearing performance of baleen,

beaked whales.

•Currently developing predictive

model of effects from inpulse noise

(explosives, air guns, etc.)

Outer Ear

Inner Ear

Middle Ear

area

Ue

Pe Lh Cb Rh

Lds

Cds

Rds

Eardrum 

conductive part

Ldm Cdc Rdc 1:Nt

Cm

Diffraction 

sound 

field

Air 

Plug Concha

Earcanal

Li Ls Cal Ral Lv Cochlea Incus Stapes

Annular 

ligament

Vestibular 

Volume

Uc

Lo

Ro

Pc Rc

Round Helicotrema

window

Incudostapedal 

joint

MalteoIncudal 

joint

Lever 

and area 

ratio

Eardrum 

independent 

part Bulla

Rmi

Cmi Cis

Ris Crw

Rdf

Ldf

2P P

Lpl

Rpl L1 L2 L3

A1 A2 A3

length

Develop Predictive Models of Auditory

Response (Ketten, Price)

Outer Ear

Middle Ear

Inner Ear
143

MARINE MAMMAL ACOUSTIC SAFETY CRITERIA

EXPLOSION SIMULATOR TEST ENCLOSURE

Pulse waveform

Frequency-kHz / Masking Noise-dB re: 1 μPa2/Hz

0.4/95 3/67 3/90 10/63 20/63 20/73 20/76 75/70 75/67

dB re: 1 

μPa

175

180

185

190

195

200

205

Altered Behavior

TTS 

? ?

?

MARINE MAMMAL ACOUSTIC SAFETY CRITERIA

FY98 ERAT End of Year Review

Results to Date
144

NSMRL: Psychological

Results

• No divers aborted any of the dives

• Auditory thresholds from 100 - 500 Hz decrease

linearly with frequency from 99 to 85 dB re 1μPa

• The aversion function is U-shaped with a minimum at

250 Hz

• Increasing duration from 7 to 28 seconds did not

increase aversion

• Divers started reporting aversion rating at or above

severe at 148 dB
145

D: Presentation Dropouts versus Sound Pressure Level

Sound Pressure Level (dB re. 1 uPa)

Cumulative Percentage of Dropouts

0

2

4

6

8

10

12

14

16

18

125 130 135 140 145 150 155 160

MCES - multi-method

controlled exposure studies

• Put the animals in their environment

– physical, chemical, biological, social, other human

activities.

• Strive to recreate the 3-D movements of the

animals

– surface observations, plus underwater acoustic

monitoring, tagging, and other tools

• Use a controllable source

– start very safe and step up, monitoring as you go.
146

The SURTASS LFA

Scientific Research Program

Passive Acoustic Monitoring Tools

(Gedamke, UCSC. Minke whales on the Great Barrier Reef)
147

HEALTH

ASSESSMENT

Sound Transport Pollution

Nervous

System

Immune System

EXPOSURE

INTERVENTION

Wild Populations

Thermal

Challenge

5

ONR Romano Immune Feb

1999

Monitoring & Mitigation

• What you don’t know CAN hurt you

– monitor to verify predicted sound field, distribution and

abundance of species of concern.

– monitor to accrue data that reduces current

precautionary standards based on uncertainty

– monitor to effectively deploy mitigation

• Monitoring is more than whalewatching!

– Doing more than recording surface detections usually

pays off

– use passive acoustics used for other tasks

– use environmental data to account for variables other

than sound which might also affect activity.
148

Mitigation

• Your two best mitigation tools are:

– choose sites, times with the least impact

– a quieter source with better energy focusing or

receive/signal processing

• Monitoring is data: prepare the infrastructure to

use lessons learned from previous activities in

future activities

– animal distribution data

– responses of animals to sound source

– effectiveness of mitigation

Marine Mammal Science

Environmental Compliance

Critical S&T Areas

[established by 1995 NRC Panel Report, 1997-98 LF Sonar Science Advisory Board, 1998 Workshop on Effects of Anthropogenic Sound]

• Hearing

– low frequency hearing thresholds

– masked hearing thresholds, critical ratios

– temporary threshold shift effects

– hearing damage from impulse sound (explosives, sonic boom)

– hearing from anatomy and remote physiological msmts.

• Behavior

– behavioral changes correlated with exposure to human noise.

– Uses of sound by marine mammals, functional significance.

– Long term effects such as changes in distribution, sensitivity.

• Tools

– attachable tags, sensors, dataloggers

– use passive acoustics to monitor vocal animals (e.g. SOSUS)

• novel sensors; active sonar, infrared, satellite imagery

• Risk assessment & prediction models.
149

REFERENCES

Ketten, D. R. 1995. Estimates of blast injury and acoustic trauma zones for marine mammals from

underwater explosions. Pp. 391-407. In Kastelein, RA., J.A. Thomas and P.E. Nachtigall, eds.,

Sensory Systems of Aquatic 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: 346-351.

Kryter, K.D. 1985. The Effects of Noise on Man. Academic Press, Orlando, FL.

Price, G.R. and J.T. KaIb. 1996. Evaluation of hazard from intense sound with mathematical model

of the human ear. J. Acoust. Soc. Am., 100:2674.

Richarson, 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, I. Kamolnick, C.E. Schlundt, and W.R. Elsberry. 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 μPa. Technical Document,

NCCOSC RDT&E DIV D3503, 49620 Beluga Rd., San Diego, CA 92152, June 1997.

Urick, 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 91-220. July, 1991.
150

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.
151

SUMMARY

RECOMMENDATIONS AND PROPOSED ACTION ITEMS

As explained in the introduction, this meeting incorporated more formal presentations than in past

MMS protected species workshops and used a panel of experts (see Appendix B) instead of breakout

groups and discussion leaders. The presentations provided updates and background on biological

research and industry technology and activities; they also addressed the status of the Marine

Mammal Protection Act and Endangered Species Act. 

After the presentations, the panelists addressed issues of concern in their areas of expertise, followed

by questions, discussion and debate with the audience. Attendees also submitted written comments

and information to the MMS. A court reporter provided transcripts for this session, in addition to

a post-workshop, closed meeting held with the panel, MMS staff, and other federal representatives

on the following day. 

From these sources, an outline of findings and recommendations was prepared and a list of all

potential action items identified. This list was then evaluated in terms of potential MMS actions and

relevance to MMS regulatory responsibilities. What follows is the MMS response to the information

and recommendations provided from the workshop.

BASELINE INFORMATION

Although information about GOM cetaceans has increased dramatically in the last 5-10 years, the

workshop participants repeatedly stressed the need for additional information on species

composition, numbers, seasonal distribution patterns and environmental correlates. In addition to

“better numbers,” we need better to understand population trends and to detect any abnormal

changes attributable to human activities.

Any group working on protected species concerns in the GOM needs these data. For NMFS, the

information is an essential part of their stock assessment efforts. For MMS and the Navy, the

information may be considered as baseline information for potential effects assessment. This type

of research is a prime candidate for cooperative efforts and, if not co-funded, needs to be

coordinated at a regional level—not only through MMS OCS Planning Areas but at a Gulf of

Mexico—Caribbean Sea scale.

Of particular concern to MMS is the move by industry into deepwater regions of the GOM and the

eastern planning area off Florida. Both the panel and the audience agreed strongly on the need to

conduct surveys before industry arrives. Both groups also agreed on the need to conduct surveys

based on biological distributions and physical features rather than on artificial political boundaries,

which cetaceans and sea turtles do not recognize. Expanding survey work into Mexican and

Caribbean areas was recommended. 

Also of importance to MMS were comments on cetacean versus sea turtle studies. While sea turtles

“are recorded” during cetacean surveys, such sightings are but lagniappe: the field efforts are
152

designed for cetaceans and are notably ineffective for detecting sea turtles, in particular, younger

(= smaller) life stages.

MMS has renewed an interagency agreement with NMFS to fund marine mammal observers aboard

NMFS spring and fall plankton cruises in the GOM and to pay for data analyses. We are exploring

options to conduct cruises in Mexican waters. 

Meetings are now held with NMFS and the Navy to better coordinate marine mammal field

programs in the GOM and Caribbean. At a minimum, new lines of communication and increased

awareness of respective MMS, NMFS and Navy marine mammal studies have been established.

Potential for additional cooperative ventures is being explored.

MMS has offered to participate in a planning meeting hosted by NMFS to determine what types of

research can be conducted to study sea turtles in deepwater habitats.

EFFECTS OF INDUSTRY

The workshop addressed numerous potential impacts of human activities on GOM manatees, sea

turtles, and cetaceans. A fundamental issue, closely related to baseline studies, is how to detect and

monitor changes attributable to human impacts and what would be needed to do so. Among the ideas

discussed were power analyses to design monitoring programs, ensure long-term efforts, and

evaluate the use of offshore platforms as part of field programs. Effects of contaminants,

commercial and recreational vessel activities, and noise-producing activities were the predominant

topics.

In terms of petroleum industry activities and MMS priorities, the shift to deepwater may expose a

significantly different cetacean community (relative to shelf species) to various types of impacts.

Of these impacts, the effects of noise and the response of cetaceans to deepwater structures are

considered the least understood yet the most certain impacts. The industry activity most likely to

create noise impacts was identified as seismic exploration and the species of most concern was the

sperm whale. The use of explosives to remove offshore structures was another concern as were oil

spills; a large oil spill would have potentially catastrophic impacts, although it is a low-probability

event. The lack of information on acoustic effects and/or explosive pressure waves coupled with the

fact that these events are operational, not accidental, are compelling reasons to elevate research on

these topics to the highest priority for effects studies.

The demand for definitive data on impacts of noise pollution on cetaceans has perhaps intensified

since the workshop. While military activities have garnered the most public attention and

commercial shipping is acknowledged as the major source of anthropogenic noise, it is clear that

seismic operations also represent an undefined, potential threat to cetaceans and perhaps to sea

turtles as well.

Strong and clear recommendations from the workshop experts were used to justify a modification

to the existing agreement with NMFS to conduct cetacean surveys. Additional cruises have been

added, dedicated to research on GOM sperm whale populations, acoustic measurements, and the
153

effects of air guns on sperm whales. The new program—Sperm Whale Acoustic Monitoring

Program (SWAMP)—began with a pilot study in June 2000.

Numerous meetings have been held with the Navy since the workshop. The Office of Naval

Research (ONR) has joined MMS and NMFS as an active research partner. ONR has provided

digital recording tags (D-tags) that are placed on sperm whales and record whale movement and

received sounds. In FY2001, satellite tags, funded through ONR, will also be used for recording

long-term movement of tagged whales.

MMS has included support for biopsy samples (all species) and DNA analysis of sperm whale tissue

during all NMFS-MMS cruises. Archived tissue samples may be used for contaminant analyses.

DNA analyses will be used for genetic assessment of sex, family groupings, and stock uniqueness

for sperm whales. NMFS will conduct DNA analyses on other cetacean species.

The above MMS responses are expected to cost more than $1 million by FY2001 and to continue

through FY2003. These were considered the highest priority for research funds, and costs to

accomplish research in deep water are substantial.

OTHER ACTIONS

MMS has also attempted to address several other issues raised at the workshop.

There were several comments from the audience on the need to present issues in plain English and

to make information available to the public. This need is not unique to protected species issues;

workshop comments reinforced a recognized problem. MMS has established a comprehensive

homepage on the Internet, and many environmental studies reports can be downloaded. A special

effort was made to describe SWAMP in plain English—details of the pilot cruise may be found:

http://www.gomr.mms.gov/homepg/regulate/environ/marmam/sperm_research.html. This address

will be updated as research progresses.

It was suggested that MMS support the Southeast Marine Stranding Network. Since the workshop,

the Louisiana Marine Mammal and Sea Turtle Rescue Program has been re-established at the

Audubon Aquarium of the Americas. MMS has played an active role at meetings and helped

establish federal contacts. Funding support for this program remains an option.

The role of industry in supporting GOM protected species research was sharply debated several

times during the workshop. Since the workshop, several industry workshops and special sessions

at national meetings have taken place. Industry cooperation for proposed air gun experiments in

SWAMP is likely. The seismic industry is exploring funding research on acoustic effects on marine

mammals in the form of an international granting program run through an independent research

management organization.

MMS has held extensive talks with NMFS on the regulation of seismic operations and explosive

removals. An environmental assessment of all GOM geological and geophysical exploration

methods regulated by the MMS is underway. New Section 7 consultations (under the ESA) with
154

NMFS on use of explosives are anticipated. These efforts should lead to an agreement on industry

requirements for take permits and provide answers to questions raised at the workshop on MMPA

compliance.

Issues related to manatees, discreet stocks of bottlenose dolphins, and post-hatchling movements

of sea turtles in the eastern OCS planning area (Florida panhandle) are under consideration, pending

management decisions on leasing. Options to conduct detailed cetacean surveys in the DeSoto

Canyon area have been discussed with NMFS.
155

APPENDIX A

MARINE PROTECTED SPECIES WORKSHOP

New Orleans Airport Hilton

June 15-16, 1999

Agenda

TUESDAY, JUNE 15

BACKGROUND

8:30-8:35 Opening Remarks

Mr. Hammond Eve

Minerals Management Service

8:35-8:45 Objectives/Introductions

Dr. William Lang and Ms. Dagmar Fertl

Minerals Management Service

8:45-9:15 KEYNOTE: History of Protected Species in the Gulf of Mexico

Dr. William Evans, Retired

(last w/Texas A&M University)

9:15-9:35 Relevant Legislation (Marine Mammal Protection Act, Endangered

Species Act)

Dr. Robert Hofman

Marine Mammal Commission

Mr. David Bernhart

National Marine Fisheries Service

9:35-9:50 Break

BIOLOGY

9:50-10:20 GulfCet I, II – Cetaceans, Turtles, and Habitat Consideration

Dr. Keith Mullin

National Marine Fisheries Service

10:20-10:40 Manatees in the Gulf of Mexico

Dr. Robert Bonde

U.S. Geological Survey
156

10:40-11:00 Review of Sea Turtle Information for the Gulf of Mexico

Dr. Maurice Renaud

National Marine Fisheries Service

11:00-12:30 Lunch

INDUSTRY; MAN-MADE AND NATURAL ACTIVITY IMPACTS ON MARINE

MAMMALS AND SEA TURTLES

12:30-12:50 MMS and Deepwater Activities

Mr. B.J. Kruse

Minerals Management Service

12:50-1:20 Offshore Platform Operations

Ms. Sandi Fury

Chevron

1:20-1:50 Acoustic Activities of Industry

Dr. Jack Caldwell

Schlumberger Geco-Prakla

1:50-2:40 Explosive Structure Removals/Navy Explosives Testing

Mr. Gregg Gitschlag

National Marine Fisheries Service

Mr. William Sloger

Department of the Navy

2:40-2:55 Break

2:55-3:40 Human Activities and Natural Events: Impacts on Gulf of Mexico

Marine Mammals

Dr. Bernd Würsig

Texas A&M University

Dr. Jeffrey Norris

Texas A&M University

3:40-4:25 Human Activities and Natural Events: Impacts on Gulf of Mexico

Sea Turtles

Dr. David Owens

Texas A&M University

4:30-6:00 Social

Ballroom C
157

WEDNESDAY, JUNE 16

REVIEW OF RELATED RESEARCH AND MONITORING PROGRAMS

9:00-9:15 Role of a Non-Governmental Organization

Ms. Sharon Young

Humane Society of the United States

9:15-10:00 National Oceanic and Atmospheric Administration Gulf of Mexico

Marine Mammal and Sea Turtle Programs

A. Contaminants and Stranding

Dr. Teri Rowles

National Marine Fisheries Service

B. National Ocean Service and Sea Turtles

Mr. Michael Coyne

National Ocean Service

C. Sea Turtles and the National Marine Fisheries Service

Ms. Sheryan Epperly

National Marine Fisheries Service

10:00-10:15 U.S. Geological Survey/National Park Service Sea Turtle Research

and Monitoring Programs in Texas

Ms. Donna Shaver

Biological Resources Division

10:15-10:30 Corps of Engineers Protected Species Concerns in the Gulf of Mexico

Dr. David Nelson

Corps of Engineers

10:30-10:45 The Navy and Marine Mammal Concerns That Can Apply to the

Gulf of Mexico

Dr. Robert Gisiner

Office of Naval Research

10:45-12:30 Lunch
158

EXPERT PANEL DISCUSSION (Open to attendees)

12:30-2:45 Dr. Robert Bonde, U.S. Geological Survey

Mr. Michael Coyne, National Ocean Service

Dr. Roger Gentry, National Marine Fisheries Service

Dr. Robert Gisiner, Office of Naval Research

Dr. Robert Hofman, Marine Mammal Commission

Dr. Thomas Jefferson, Ocean Park Conservation Foundation

Ms. Barbara Schroeder, National Marine Fisheries Service

Dr. Peter Tyack, Woods Hole Oceanographic Institute

2:45-3:00 Break

3:00-5:00 Public Comment
159

APPENDIX B

EXPERT PANEL MEMBERS

Dr. Robert Bonde, U.S. Geological Survey

Mr. Michael Coyne, National Ocean Service

Dr. Roger Gentry, National Marine Fisheries Service

Dr. Robert Gisiner, Office of Naval Research

Dr. Robert Hofman, Marine Mammal Commission

Dr. Thomas Jefferson, Ocean Park Conservation Foundation

Ms. Barbara Schroeder, National Marine Fisheries Service

Dr. Peter Tyack, Woods Hole Oceanographic Institute
161

APPENDIX C

ATTENDEES

Adams, Craig 

Snc Technologies Corp.

P.O. Box 576

Avon, CT 06001

adams@pcnet.com

Allen, Dan 

Ecologist

Chevron USA Production Co.

935 Gravier St.

New Orleans, LA 70112

allj@chevron.com

Avent, Robert M

Oceanographer

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Barton, Warren J

Environmental Scientist

MMS

1201 Elmwood Park MS 5440

New Orleans, LA 70123

warreb.barton@mms.gov

Bassim, Khaled 

MMS

381 Elden St. MS 4030

Herndon, VA 20170

khaled.bassim@mms.gov

Becnel, Tom 

Sr. Staff Regulatory Comp. Rep.

Burlington Resources

400 N. Sam Houston Prkwy. E., #1200

Houston, TX 77060

Tbecnel@br-inc.com

Bell, Joel T

Duke University

707 Louise Cr. #G

Durham, NC 27705

joel.bell@duke.edu

Benner, Lee 

Oceanographer

MMS

381 Elden St

Herndon, VA 20170

lee.benner@mms.gov

Bennett, Richard 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Bernhart, David 

NMFS

9721 Executive Ctr Dr. North

Saint Petersburg, FL 33702-2439

davis.bernhart@noaa.gov

Boland, Greg 

Biologist

MMS

2164 Champions Dr

La Place, LA 70068

gregory.boland@mms.gov

Bonde, Robert K

U.S. Geological Project

Florida Caribbean Science Ctr.

412 N.E. 16th Ave., Rm. 250

Gainesville, FL 32601-3701

robert_bonde@usgs.gov
162

Borggaard, Diane 

NMFS

9721 Executive Ctr Dr. North

Saint Petersburg, FL 33702-2439

Brewer, Gary 

Biologist

USGS Bio. Resources

1700 Leetown Rd

Kearneysville, WV 25430

gary_brewer@usgs.gov

Brinkman, Ron 

Geophysicist

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

ronald.brinkman@mms.gov

Bull, Ann 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Caldwell, Jack 

Schlumberger

1325 South Dairy Ashford

Houston, TX 77077

caldwell@houston.geco-parkla.sld.com

Carroll, Lyn 

Environmental Manager PEO,TSC

2531 Jefferson Davis Hwy

Arlington, VA 22242-5165

carrolllb@navsea.navy.mil

Cates, Charlotte 

NMFS/Johnson Controls

3209 Frederic St.

Pascagoula, MS 39567

cecates@juno.com

Coar, Lawrence F

NAWCAD Det. Key West

Pier D-1, Bldg B-28

P.O. Box 9013

Key West, FL 33040-9013

coarlf@navair.navy.mil

Codina, Caron 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

caron.codina@mms.gov

Congdon, Barney 

Public Affairs Officer

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

byron.congdon@mms.gov

Cooke, David W

Chief, Resource Studies

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Coyne, Michael 

NOS-NOAA

1305 East-West Hwy.

SSMC IV, Rm. 9216

Silver Spring, MD 20902

mcoyne@seaturtle.org

Dauterive, Les 

Sr. Environmental Scientist

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

lester.dauterive@mms.gov
163

Defenbaugh, Rick 

Deputy Regional Supv.

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Dorsett, Chris 

Program Director - Fisheries

Gulf Restoration Network

P.O. Box 2245

New Orleans, LA 70176

cdgrn@igc.org

Engelhaupt, Dan 

Univ. of Durham - England

9195 Jamaica Beach

Galveston, TX 77554

danengelhaupt@hotmail.com

Epperly, Sheryan 

NOAA Fisheries

75 Virginia Beach Drive

Key Biscayne, FL 33149

sheryan.epperly@noaa.gov

Evans, William 

Texas A&M University

21 Cedar Lawn North

Galveston, TX 77551-1675

weebio@aol.com

Eve, Hammond 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Fagot, Caryl 

Staff Assistant

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

caryl.fagot@mms.gov

Fertl, Dagmar 

Biologist

Geo-Marine

550 East 15th Street

Plano, TX 75074

dagmar.fertl@mms.gov

Fisher, Michael A

U.S. Geological Survey

345 Middlefield Rd MS 999

Menlo Park, CA 94025

mfisher@octopus.wr.usgs.gov

Fisher, William S

U.S. EPA NHEER/GULF ECO. DIV.

1 Sabine Island Dr.

Gulf Breeze, FL 32561

fisher.william@epa.gov

Froomer, Dr. Norman 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Fury, Sandi 

Chevron USA Production Co.

935 Gravier St. Rm. 1364

New Orleans, LA 70112

sfur@chevron.com

Gallagher, Pat 

Defence Scientist

National Defence - Canada

DRES

P.O. Box 4000

Medicine hat, T1A8K6

pat.gallagher@dres.dnd.ca

Gaspin, Joel 

Naval Surface Warfare Ctr

101 Strauss Ave

Indian Head, MD 20640-5035

joelgaspin@uwtech.ih.navy.mil
164

Gentry, Roger 

NMFS - OPR

1315 East-West Hwy.

Silver Spring, MD 20910

roger.gentry@noaa.gov

Gisiner, Robert 

Office of Naval Research

800 North Quincy St.

Arlington, VA 22217-5660

gisiner@onr.navy.mil

Gitschlag, Gregg 

NOAA/NMFS

4700 Avenue U

Galveston, TX 77551

gregg.gitschlag@noaa.gov

Goeke, Gary 

Chief, Eastern Gulf Info. Office

MMS

41 N. Jefferson #300

Pensacola, FL 32501

ggoeke@networktel.net

Griffin, Nancy 

Mote Marine Laboratory

1600 Ken Thompson Prkwy

Sarasota, FL 34231

ngriffin@mote.org

Griffin, Robert B

Mote Marine Laboratory

1600 Ken Thompson Prkwy

Sarasota, FL 34231

bgriffin@mote.org

Guillen, George 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

george.guillen@mms.gov

Hampton, George 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Harris, Anne 

Audubon Institute

1 Canal St.

New Orleans, LA 70130

keeledover@hotmail.com

Hemphill, Kenneth W

Program Administrator

LA DHH

6867 Bluebonnet Rd

Baton Rouge, LA 70818

khemphil@dhhmail.dhh.state.la.us

Hickerson, Emma 

Research Coordinator

Flower Garden Banks

National Marine Sanctuary

216 W 26th St #104

Bryan, TX 77803

ema.hickerson@noaa.gov

Hill, Maurice 

MMS Pacific Region

770 Paseo Camarillo

Camarillo, CA 93010

maurice.hill@mms.gov

Hinderstein, Lara 

Texas A&M University

5007 Aveune U #105

Galveston, TX 77551-5932

hinderst@tamug.tamu.edu

Hofman, Robert 

Marine Mammal Comm.

4340 East-West Hwy, Rm. 905

Bethesda, MD 20814
165

Hoggard, Wayne 

NOAA/NMFS

3209

Frederic St

Pascagoula, MS 39567

whoggard@trition.pas.nmfs.gov

Holder Jr., Samuel 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

samuel_holder@mms.gov

Hubard, Carrie 

NMFS/Johnson Controls

3209 Frederic St.

Pascagoula, MS 39567

chubard@triton.pas.nmfs.gov

Ironside, Kevin 

SAIC

1140 Eglin Parkway

Shalimar, FL 32579

ironside@ntserver.eglin.af.mil

Jefferson, Thomas 

Ocean Park Consv.

11463 Madera Rose Way

San Diego, CA 92124

sclymene@aol.com

Kendall, James J

Chief, Environmental Sci. Section

MMS

381 Elden St MS 4023

Herndon, VA 20170

james.kendall@mms.gov

Kruse, B.J. 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

james.regg@mms.gov

Labbe, Simon 

5 Montee Des Arscnaux

Le Gardeur, J5Z 2P4

labbes@tisnc.snc-lavalw.com

LaBrecque, Erin 

NMFS/Johnson Controls

3209 Frederic St.

Pascagoula, MS 39567

Landry Jr., Andre M

Professor/Chairman

Texas A&M University

Dept of Marine Biology

5001 Ave. U #104

Galveston, TX 77551

landrya@tamug.edu

Lang, William 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Lavergne, David 

Resource Economist

LA DWF

P.O. Box 98000

Baton Rouge, LA 70898

lavergne_ur@wlf.state.la.us

Lee III, Walter 

Estimating Mgr.

Bean Dredging Corp.

619 Engineers Rd

P.O. Box 237

Belle Chasse, LA 70037

Leedy, Chad 

JCI/NMFS

3209 Frederic St.

P.O. Box 1207

Pascagoula, MS 39568-1207
166

Lenhardr, Martin 

Professor

Virginia Commonwealth Univ.

Box 980168 - MCU

Richmond, VA 23298-0160

lenhard1@gems.vcu.edu

McBride, David J

Dominion E&P, Inc

1450 Poydras St

New Orleans, LA 70112

david_j_mcbride@dom.com

Monroe, R. Scott 

Naval Sea Sys. Command

2531 Jefferson Davis Hwy

(PMS400D53)

Arlington, VA 22242

monroers@navsea.navy.mil

Moran, David 

Environmental Scientist

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Mota, Alba 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Mullin, Keith 

NMFS

P.O. Drawer 1207

Pascagoula, MS 39568-1207

kmullin@triton.pas.nmfs.gov

Nelson, David 

USAE Waterways Exp. St.

3909 Halls Ferry Rd.

Vicksburg, MS 39180-6199

nelson@mail.wes.army.mil

Norris, Jeffrey 

Texas A&M University

5007 Aveune U

Bioacoustics Lab

Galveston, TX 77551-5932

norrisj@tamug.tamu.edu

Owens, David 

Texas A&M University

Dept of Biology

Texas A&M University

College Station, TX 77843

daveo@bio.tamu.edu

Paniszczyn, William 

Marconi Systems Technologies

2611 Jefferson Davis Hwy #5000

Arlington, VA 22202

Parker, Mike 

Sr. Staff Engineer

Exxon Company USA

P.O. Box 2180

Room 4289 EB

Houston, TX 77252-2180

mike.e.parker@exxon.com

Pausina, Randall 

LA DWF

P.O. Box 37

Lyle S. St. Amant Marine Lab

Grand Isle, LA 70358

pausina_rb@ldwf.state.la.us

Peggion, Germana 

Univ. of Southern Mississippi

Bldg 1103 Room 249

Stennis Space Ctr, MS 39529

germana.peggion@usm.edu

Perkins, A. Frank 

HSE Supr.

1450 Poydras #2020

New Orleans, LA 70160

frank.perkins@uaii.com
167

Peters, Dennis 

SAIC

1140 Eglin Parkway

Shalimar, FL 32579

dennis.j.peters@cpmx.saic.com

Pierson, Mark O

Wildlife Biologist

MMS

770 Paseo Camarillo

Camarillo, CA 93010

mark.pierson@mms.gov

Poe, Billy 

President, Explosive Svcs. Intl.

P.O. Box 45742

Baton Rouge, LA 70895

explosive@earthlink.com

Powell, James A

Florida DEP

100 8th Ave. S.E.

Saint Petersburg, FL 33701

powell_ja@epicf.dep.state.f1.us

Reaves, Darlene 

Teacher

N. O. Ctr. for Sci/Math

3605 Haring Rd

Metairie, LA 70006

dreaves@wave.tcs.tulane.edu

Reggio, Jr., Villere 

Outdoor Recreation Planner

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

villere.reggio@mms.gov

Renaud, Maurice 

NOAA/NMFS

4700 Avenue U

Galveston, TX 77551

maurice.renaud@noaa.gov

Roden, Carol 

NMFS

3209 Frederic St

Pascagoula, MS 39567

croden@triton.pas.nmfs.gov

Rogers, Robert 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Roscigno, Pat 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Rouse, Mark 

Sr. Staff Assistant

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

mark.rouse@mms.gov

Roussel, John 

Asst. Secretary

LA DWF

P.O. Box 98000

Baton Rouge, LA 70898

roussel.je@wlf.state.la.us

Schexnayder, Mark 

Marine Fisheries Agent

LSU Extension/Sea Grant

1855 Ames Blvd

Marrero, LA 70072

mschexnayder@agctr.lsu.edu

Schmahl, G.P. 

Flower Garden Banks

National Marine Sanctuary

216 W 26th St #104

Bryan, TX 77803

george.schmahl@noaa.gov
168

Schroeder, Barbara 

NMFS - OPR

1315 East-West Hwy.

Silver Spring, MD 20910

barbara.schroeder@noaa.gov

Self Sullivan, Caryn 

Texas A&M University

Mail stop 2258

College Station, TX 77843

caryn_sullivan@hotmail.com

Shah, Arvind 

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

arvind.shah@mms.gov

Shaver, Donna 

Padre Island Nat. Seashore

9405 South Padre Island Dr.

Corpus Christi, TX 78418

donna_shaver@nps.gov

Sinclair, James E

MMS

4425 Calumet

Metairie, LA 70001

james.sinclair@mms.gov

Sloger, William 

Naval Facilities Engineering

2155 Eagle Drive

Box 190010

Charleston, SC 29406

slogerwr@efdsouth.navfac.navy.mil

Spaulding, Rick 

Sr. Biologist/Project Mgr

The Environmental Co.

1111 Chapala St.

Santa Barbara, CA 93101

Swartz, Steven L

NOAA Fisheries

75 Virginia Beach Drive

Key Biscayne, FL 33149

steven.swartz@noaa.gov

Taillon, Stephanie 

Student

LSU

4705 Alvin Dark #2

Baton Rouge, LA 70820

steph3260@aol.com

Teas, Wendy 

Research Fishery Biologist

NOAA/NMFS/SEFSC

75 Virginia Beach Dr

Key Biscayne, FL 33149

wendy.teas@noaa.gov

Tidemann, Arlen 

Manager

National Response Corp.

11200 Westheimer #850

Houston, TX 77042

a-tidemann@nrcxchange.nrcc.com

Tyack, Peter 

Woods Hole

Redfield 1-32

45 Water St.

Woods Hole, MA 02543-1049

ptyack@whoi.edu

Velez, Peter K

Manager Regulatory Affairs

Shell E&P Co.

P.O. Box 61933

New Orleans, LA 70161

pkvelez@shellus.com
169

Vergel C. Jamir, Tomas 

Program Director

Gulf and South Atlantic Fisheries Foundation

Lincoln Ctr Suite 997

5401 W. Kennedy Blvd

Tampa, FL 33609

tom.jamir@worldnet.att.net

Viada, Stephen 

Sr. Staff Scientist

Continental Shelf Assoc. Inc.

328 Aris Ave

Metairie, LA 70005

sviada@gs.net

Vigil, Debra 

MMS

1201 Elmwood Prk Blvd

MS 5431

New Orleans, LA 70123

debra_vigil@mms.gov

Williams, Page S

Houston Audubon Society

4229 W. Alabama St

Houston, TX 77027-4921

75761.2651@compuserve.com

Wilson, Judy 

Marine Biologist

MMS

381 Elden St. MS 4042

Herndon, VA 20170

judy-wilson@mms.gov

Winbush, Debra 

Public Affairs Specialist

MMS

1201 Elmwood Prk Blvd

New Orleans, LA 70123

Wursig, Bernd 

Texas A&M University

4700 Avenue U, Bldg 303

MMR Program

Galveston, TX 77551-5932

wursigb@tamug.tamu.edu

Wyatt, Henry 

General Offshore

Cable and Wireless Marine

P.O. Box 1583

Key West, FL 33041

wyatthj@navair.mil

Young, Sharon 

Humane Society - U.S.

22 Washburn St

Bourne, MA 02532

sbyoung@capecod.net

Zebouni, Mia 

Tulane University

7716 Willow St.

New Orleans, LA 70118

mzeboun@tcs.tulane.edu
171

INDEX TO AUTHORS

Bernhart, Mr. David . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Bonde, Dr. Robert K. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Caldwell, Dr. Jack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Coyne, Mr. Michael S. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Davis, Dr. Randall W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Epperly, Ms. Sheryan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

Evans, Dr. William E. ..........................................................8

Fertl, Ms. Dagmar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Fury, Ms. Sandra M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Gisiner, Dr. Robert C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

Gitschlag, Mr. Gregg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Hofman, Dr. Robert . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Kruse, Mr. B.J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Lang, Dr. William .............................................................1

Lefebvre, Dr. Lynn W. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Mullin, Dr. Keith D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Nelson, Dr. David A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125

Norris, Dr. Jeffery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Owens, Dr. David . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Regg, Mr. Jim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Renaud, Dr. Maurice L. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Rowles, Dr. Teri . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Shaver, Ms. Donna J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Sloger, Mr. William . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Würsig, Dr. Bernd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Young, Ms. Sharon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
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 Minerals Revenue Management 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.