OCS Study 

MMS 2003-069 

 

Sperm Whale Seismic Study 

in the Gulf of Mexico 

Annual Report: Year 1 

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 2003-069 

Sperm Whale Seismic Study 

in the Gulf of Mexico 

Annual Report: Year 1 

Editors 

Ann E. Jochens 

Douglas C. Biggs 

Prepared under MMS Contract 

1435-01-02-CA-85186 

by 

Texas A&M University 

Department of Oceanography 

College Station, Texas 77843-3146 

Published by 

New Orleans

December 2003 
iii

DISCLAIMER

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

the Texas A&M Research Foundation. This report has been technically reviewed by the MMS,

and it has been approved for publication. Approval does not signify that the contents necessarily

reflect the views and policies of the MMS, nor does mention of trade names or commercial

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

and compliance with the MMS editorial standards.

REPORT AVAILABILITY

Extra copies of the 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: (504) 736-2519 or

1-800-200-GULF

CITATION

Suggested citation:

Jochens, A.E. and D.C. Biggs, editors. 2003. Sperm whale seismic study in the Gulf of Mexico;

Annual Report: Year 1. U.S. Dept. of the Interior, Minerals Management Service, Gulf of

Mexico OCS Region, New Orleans, LA. OCS Study MMS 2003-069. 139 pp.

ABOUT THE COVER

The cover art shows a sperm whale beginning a dive in Mississippi Canyon Block 127 in the

northern Gulf of Mexico (photo by Christoph Richter).
v

ACKNOWLEDGMENTS

This report would not have been possible without the contributions of a large number of people.

Each principal investigator (PI) of the Sperm Whale Seismic Study (SWSS) contributed ideas to

and authorship of portions of the text, many participated in the cruises and in data reduction and

processing. The principal investigators, their affiliations, and their tasks are:

Ann E. Jochens TAMU Program Manager, Co-PI for habitat characterization

Douglas C. Biggs TAMU Project Scientist, PI for habitat characterization

Dan Engelhaupt UDurham PI for genetic analyses

Jonathan Gordon Ecologic PI for Photo I.D. and S-tag acoustics

Matthew K. Howard TAMU Data Manager

Nathalie Jaquet TAMUG Co-PI for Photo I.D.

Mark Johnson WHOI Co-PI for D-tag study

Robert L. Leben CU Co-PI for habitat characterization

Bruce Mate OSU PI for S-tag whale tagging and tracking

Patrick Miller WHOI Co-PI for D-tag study

Peter Tyack WHOI PI for D-tag study

Bernd Würsig TAMUG Co-PI for Photo I.D.

Additionally, Dr. Aaron Thode of SIO, Dr. Steven F. DiMarco of TAMU, and Dr. Joel Ortega of

OSU contributed to the authorship of this report, as well as to processing and analysis of data

sets. We appreciate the contributions of Dr. Chuanmin Hu, Executive Director of the Institute for

Marine Remote Sensing at the College of Marine Science of the University of South Florida, for

providing ocean color images and ideas.

To all who participated on the two legs of the SWSS cruise we extend our great appreciation for

making the 2002 field program a great success. In particular, thanks to the S-tag cruise science

team: Doug Biggs (TAMU College Station), Eddie Webb (TAMU College Station), Paul Clark

(TAMU GERG), Bill Green (TAMU Galveston), Mike Fredericks (TAMU GERG), Bruce Mate

(OSU Newport), Mary Lou Mate (OSU Newport), Ladd Irvine (OSU Newport), Daniel Palacios

(OSU Newport), Nathalie Jaquet (TAMU Galveston), Joel Ortega (TAMU Galveston, now at

OSU), Christoph Richter (Canada), Will Rayment (New Zealand), Jamie McKee (SAIC), Erin

LaBrecque (New Hampshire), Larry Glickman (Oregon), Jonathan Gordon (Ecologic UK), Sarah

Tsoflias (MMS New Orleans), Ricardo Antunes (Madeira, Portugal), Reuben Heule

(Netherlands), Dan Lewer (OSU Newport), Jonathan Gordon (Ecologic UK), Nathalie Jaquet

(TAMU Galveston), Dan Engelhaupt (Durham Univ UK), Alicia Salazar (TAMU College

Station), and Terry Ketler Productions (San Francisco).

Thanks to the D-tag science team on Gyre: Mark Johnson (WHOI), Peter Tyack (WHOI), Eddie

Webb (TAMU College Station), Paul Clark (TAMU GERG), Bill Green (TAMU Galveston),

Mike Fredericks (TAMU GERG), Mark Johnson (WHOI), Patrick Miller (WHOI), Alessandro

Bocconcelli (UNCW), Nicoletta Biassoni (WHOI), Maria Elena Quero (WHOI), Dan Engelhaupt

(Durham Univ. UK), Todd Pusser (North Carolina), Amy Beier (New Zealand), Irene Briga

(Massachusetts), Mandana Mirhaj (Germany), Simon Childerhouse (DoC, New Zealand), Dee

Allen (NMNH Smithsonian), Aaron Thode (SIO), Valeria Teloni (WHOI, Italy), Matt Grund

(WHOI), Natacha Aguilar de Soto (Spain), Sarah Tsoflias (MMS New Orleans), Matthew

Howard (TAMU College Station), and Laurie Sindlinger (TAMU College Station).

Thanks to the D-tag science team on the Rylan T.: Cliff Smith (Fairfield Industries), Tony

Edwards (Fairfield Industries), Neil Estay (Fairfield Industries), Tim Pinnington (Seamap Inc.),

Craig Douglas (Seamap Inc.), Natacha Aguilar de Soto (Spain), Bill Lang (MMS New Orleans),

Carol Roden (MMS New Orleans), and Sandy Sawyer (Fairfield Industries).
vi

Finally, thanks to Joel Ortega and Dan Lewer for braving the winter waters off Louisiana in the

S-tag follow-up cruises.

Without the hard work of the ships' masters and crew, the science teams would not have been

able to complete their tasks successfully and safely. So we extend sincere thanks to Captain

Dana O. Dyer III and the crew of the R/V Gyre and to Captain Steve Bennett and the crew of the

Rylan T. for jobs well done. The dedicated shore-based efforts of Desmond Rolf, Sandy Green,

and Bill Green of the Gyre TAMU Marine Operations went above and beyond the call of duty

and contributed to the success of the study. We also thank Dr. Norman Guinasso and Mr. R. J.

Wilson of TAMU GERG for their assistance with preparing the ADCP and getting the MMS R2

tag boat delivered in time for the D-tag cruise, Dr. Ou Wang of TAMU for producing ADCP

products, and Mr. Tomas Follett of OSU for facilitating delivery of S-tag whale location

information to D-tag scientists during their cruise.

The use of a seismic source vessel, which was crucial for conducting the D-tag controlled

exposure experiment, would not have been possible without the contribution of the seismic

source and vessel, Rylan T./Speculator by the International Association of Geophysical

Contractors. SWSS scientists extend thanks to Chip Gill, Phil Fontana, and Jack Caldwell, as

well as all members of IAGC, for their enthusiastic work in support of SWSS, and to Jim

Thompson of Fairfield Industries for making the logistical arrangements for and supplying the

seismic source vessel. We thank Tim Pinnigton and Craig Douglas of Seamap, Inc., for

contributing both the Seamap hydrographic array for the seismic source vessel and their time as

its operators during the D-tag cruise.

The enthusiastic and timely support of Dr. William Lang, the MMS Project Officer, is greatly

appreciated. We also greatly appreciate the cruise participation and thoughtful support of Sarah

Tsoflias and Carol Roden of MMS. Thanks also to Dr. Robert Gisiner of ONR and Dr. Richard

Myrick of NAVO for their contributions, both in support of tag development and in contribution

of XBTs for use in field year 2002.

Finally, any program as large and complex as this one needs the help of many in the

administration of the project. We thank Phyllis Bonifazi and Martha Tackett of TAMRF, Stacie

Arms of TAMUG, Carol Delancey of OSU, and Mary Jane Tucci of WHOI for their many

efforts in support of SWSS.
vii

TABLE OF CONTENTS

PAGE

List of Figures ........................................................................................................................ ix

List of Tables.......................................................................................................................... xi

Acronyms............................................................................................................................... xiii

1. Executive Summary ................................................................................................... 1

1.1 Introduction .................................................................................................... 1

1.2 Field Measurements........................................................................................ 2

1.3 Instruments and Data Methods....................................................................... 3

1.4 Technical Summary ........................................................................................ 4

2. Introduction ............................................................................................................... 5

2.1 SWSS Background and Objectives................................................................ 5

2.2 Program Participants and Activities................................................................. 6

2.3 Report Organization........................................................................................ 9

3. Data Collection Cruises.............................................................................................. 11

3.1 S-tag Leg of SWSS 2002............................................................................... 11

3.2 D-tag Leg of SWSS 2002 .............................................................................. 29

3.3 S-tag Follow-up Cruises................................................................................. 60

4. Instrumentation and Data Methods............................................................................. 63

4.1 RHIBs ............................................................................................................ 63

4.2 S-tag Instruments and Data Methods.............................................................. 63

4.2.1 Satellite Tag Data................................................................................ 63

4.2.2 Acoustic and Visual Observations....................................................... 64

4.3 D-tag Instruments and Data Methods............................................................ 69

4.3.1 Digital Acoustics Tag Data Acquisition .............................................. 69

4.3.2 Controlled Exposure Experiments...................................................... 69

4.3.3 Visual and Acoustic Observations....................................................... 70

4.3.4 Data Analysis...................................................................................... 71

4.4 Genetic Analyses Methods............................................................................. 73

4.4.1 Genetic Markers to be Analyzed......................................................... 73

4.4.2 Genetic Data Analysis......................................................................... 74

4.5 Habitat Characterization Data Methods........................................................... 74

4.5.1 Remote Sensing Fields ....................................................................... 74

4.5.2 Flow-through Temperature, Salinity, Fluorescence and Chlorophyll... 75

4.5.3 CTD Data ........................................................................................... 75

4.5.4 XBT Measurements............................................................................ 76

4.5.5 Acoustic Doppler Current Profiler Measurements.............................. 77

4.6 Data Management........................................................................................... 81

4.6.1 Introduction ........................................................................................ 81

4.6.2 Data Manager..................................................................................... 82

4.6.3 Data Back-up...................................................................................... 83

4.6.4 Data QA/QC and the Database ........................................................... 83

4.6.5 Data Archiving Procedures................................................................. 83

4.6.6 Data Usage and Sharing ..................................................................... 84

4.6.7 Data Submission................................................................................. 84
viii

TABLE OF CONTENTS

(continued)

PAGE

5. Technical Summary .................................................................................................... 87

5.1 Sperm Whales in the Gulf of Mexico: Photo-identification,

Photogrammetry, Acoustic Analysis and Observations of Mediumscale Movements During SWSS 2002 ........................................................... 87

5.2 Identifying the Seasonal Distribution of Sperm Whales in the Gulf of

Mexico with Satellite-Monitored Radio Tags.................................................. 95

5.3 Analysis of Sperm Whale Vocalizations from a Towed Passive

Acoustic Array................................................................................................ 100

5.4 Synopsis of Diving Behavior of D-tagged Sperm Whales.............................. 104

5.5 Molecular Ecology of Sperm Whales (Physeter macrocephalus) in

the Northern Gulf of Mexico.......................................................................... 106

5.6 Ship and Satellite Studies of Sperm Whale Habitat ........................................ 108

5.7 Tracking Responses of Sperm Whales to Experimental Exposures of

Airguns........................................................................................................... 115

6. Literature Cited ........................................................................................................... 121
ix

 LIST OF FIGURES

FIGURE PAGE

2.1. Bathymetry and geographical locations in the Gulf of Mexico. ........................... 6

3.1.1. S-tag cruise track (thick gray line) for June/July 2002. Location of CTD (circles),

T7 XBT (open squares), and T10 XBT (filled squares) stations during the cruise.. 13

3.1.2. Locations of (a) acoustic contacts with sperm whales and (b) visual contacts

and tracking of sperm whales during SWSS cruise Leg 1, S-tag, June/July 2002. 14

3.1.3. Locations where (a) sperm whales were tagged with satellite tags and (b) skin

or biopsy samples were taken during S-tag, June/July 2002.. .............................. 15

3.1.4. Locations at which photographs were taken for photo-identification during

SWSS cruise Leg 1, S-tag, June/July 2002.......................................................... 22

3.1.5. Sea surface height from TOPEX/ERS-2 altimeters for 9 June 2002. ................... 23

3.1.6. Locations of water samples filtered and analyzed for chlorophyll during SWSS

cruise Leg 1, S-tag, June/July 2002..................................................................... 25

3.1.7. ADCP data collection on S-tag cruise, 20 June - 8 July 2002. ............................. 28

3.2.1. D-tag cruise track for R/V Gyre (02G11) on 21 August to 15 September 2002. ... 32

3.2.2. Schematic of airgun array of Fairfield Speculator. .............................................. 35

3.2.3. Far-field signature of airgun array....................................................................... 35

3.2.4. Amplitude spectrum of far-field signature of airgun array................................... 36

3.2.5. Locations of visual sightings of sperm whales during the 2002 D-tag cruise. ...... 38

3.2.6. Locations where sperm whales were tagged with digital tags (D-tags) during

SWSS cruise Leg 2, August/September 2002...................................................... 39

3.2.7. Dive profiles from two D-tags for sperm whales diving together. ....................... 40

3.2.8. R/V Gyre track (black) and Rylan T./Speculator track (color) during

controlled-exposure experiments on 10 and 11 September 2002. ........................ 41

3.2.9. Ship track color-coded according to which hydrophone array was in use. ........... 43

3.2.10. Numbers of acoustic contacts during the 2002 D-tag cruise. ............................... 44

3.2.11. Average sound speed profile (thin line) and perturbation after a week of

rough weather and storms had mixed the upper 50 m (thick line)........................ 45

3.2.12. Acoustic transmission loss, in dB, from a source at 800-m depth in 1000-m

deep water over a sandy bottom.......................................................................... 47

3.2.13. Locations where skin or biopsy samples were collected during SWSS cruise

Leg 2, D-tag, August/September 2002. ............................................................... 48

3.2.14. Locations of hydrographic stations on SWSS Leg 2, D-tag, in

August/September 2002...................................................................................... 50

3.2.15. Data collection from the 153-kHz ADCP on the D-tag cruise from

22 August through 13 September 2002. .............................................................. 53

3.2.16. Data collection from the 153-kHz ADCP on the D-tag cruise from

22 August through 13 September 2002. .............................................................. 54

3.2.17. Locations of near-surface chlorophyll samples during D-tag cruise in 

August/September 2002...................................................................................... 55

3.2.18. Sea surface height from TOPEX/ERS-2 altimeters for 10 September 2002. ........ 58

3.2.19. SeaWiFS image for 24 August 2002 showing chlorophyll concentration and

D-tag cruise track color-coded to salinity............................................................ 59
x

LIST OF FIGURES

(continued)

FIGURE PAGE

3.3.1. S-tag follow-up cruises activities........................................................................ 61

4.2.1. Diagrammatic representation of underwater and topside components of the

acoustic monitoring system................................................................................. 66

5.1.1. Distribution of sperm whales during the S-tag cruise in 2002.............................. 90

5.1.2. Visual survey effort during the S-tag cruise in 2002............................................ 91

5.1.3. Acoustic survey effort on SWSS 2002 S-tag cruise............................................. 92

5.1.4. Example of small-scale movements. ................................................................... 93

5.2.1. Locations of S-tag deployments.......................................................................... 97

5.2.2. S-tag deployment locations and last location determined from transmissions

to 21 December 2002.......................................................................................... 98

5.3.1. Distribution of acoustic contact times, broken down into times measured with

or without a tagging workboat present in the water during daylight hours. .......... 102

5.3.2. Derived ranges and depths of three whales using a two-array passive

acoustic localization algorithm. .......................................................................... 103

5.6.1. Caterpillar plot of currents, measured during 2002 SWSS Leg One by the

ship's 153-kHz ADCP, superimposed on the composite map of sea surface

height anomaly (cm) for 3 July 2003. ................................................................. 110

5.6.2. Property-property plot of in vivo fluorescence versus salinity for SWSS

2002 Leg One, S-tag cruise................................................................................. 111

5.6.3. Property-property plot of in vivo fluorescence versus salinity for SWSS 2002

Leg Two during 22 August through 2 September 2002. ...................................... 112

5.6.4. Property-property plot of in vivo fluorescence versus salinity for SWSS 2002

Leg Two during 3-15 September 2002................................................................ 113

5.7.1. Track of vessels and sound transmission levels for the controlled

exposure experiment conducted on 10 September 2002. ..................................... 116

5.7.2. Example of spectra for airgun pulses from CEE conducted 10 September 2002. . 117

5.7.3. Received level analysis for airgun impulse. ........................................................ 117

5.7.4. Dive pattern of sperm whale tagged for CEE conducted on 10 September 2002.. 118

5.7.5. Tracks of vessels, airgun transmission levels, and whale movements

during controlled exposure experiment conducted 11 September 2002................ 118

5.7.6. Dive profiles and creak rates for the three whales tagged for the CEE

on 11 September 2002. ....................................................................................... 119

5.7.7. Creak rates before (pre), during (exp), and after (post) exposure to airgun sounds

for the four tagged whales in the CEE conducted on 10-11 September 2002. ...... 119

5.7.8. Difference in creak rates before versus during exposure to 143-148 dB

indicates there is no change in creak rate. ........................................................... 120
xi

LIST OF TABLES

TABLE PAGE

2.1. Major tasks by academic scientists in SWSS....................................................... 7

2.2. Cruise leg identifiers and dates........................................................................... 9

3.1.1. The SWSS 2002 cruise, Leg 1, S-tag science team.............................................. 12

3.1.2. Locations, dates, and times of the tagging of sperm whales with S-tags. ............. 16

3.1.3. Biopsy/genetic typing tissue samples collected during S-tag fieldwork. .............. 18

3.1.4. Locations and dates of scientific photographs of sperm whales........................... 20

3.1.5. Hydrographic stations on S-tag cruise................................................................. 24

3.1.6. Extracted chlorophyll stations on S-tag cruise..................................................... 26

3.2.1. The SWSS 2002 cruise, Leg 2, D-tag science team............................................. 30

3.2.2. List of 19 D-tag placements on sperm whales.. ................................................... 33

3.2.3. Emission angles from the V1680 array for various distances corresponding

to a tagged whale at a depth of 1,000 m. ............................................................. 36

3.2.4. Timeline for ramp-up of airguns on Speculator for D-tag controlled

exposure experiments on 10 and 11 September 2002. ......................................... 42

3.2.5. Tissue collection and genetic typing samples collected during SWSS 2002

D-tag fieldwork. ................................................................................................. 49

3.2.6. Location, time, cast depth and water depth for SeaCat CTD casts taken

on the SWSS 2002 D-tag cruise.......................................................................... 51

3.2.7. XBT probe deployment locations and dates on SWSS 2002 D-tag cruise............ 52

3.2.8. Extracted chlorophyll stations on the SWSS 2002 D-tag cruise........................... 56

4.5.1. ADCP configuration summary............................................................................ 78

4.5.2. Complex regression statistics for GPS velocity versus bottom-track velocity. ..... 79

4.5.3. Results of evaluation of 153 and 38 kHz ADCP data for external factors

and number of data segments rejected................................................................. 80

5.1.1. Sperm whale resightings from SWSS 2002 S-tag cruise data. ............................. 94

5.2.1. Date and location of S-tag deployments.............................................................. 96
xiii

ACRONYMS

ADCP Acoustic Doppler current profiler

ASCII American Standard Code for Information Interchange

AVHRR Advanced Very High Resolution Radiometer

CCAR Colorado Center for Astrodynamics Research, University of Colorado

CD compact disk

CDT Central Daylight Time

CEE controlled exposure experiment

CHL chlorophyll

CORIS Coastal and Offshore Resource Information System

CTD conductivity-temperature-depth sensor

CU University of Colorado

DGPS differential Global Positioning System

DGoMB Deepwater Gulf of Mexico Benthic Habitats Program

DMSO dimethylsulfoxide

DNA deoxyribose nucleic acid

DoC Department of Conservation, Wellington, New Zealand

DODS Distributed Ocean Data System

D-tag digital acoustic tag

GERG Geochemical and Environmental Research Group at TAMU

GIS Geographical information system

GMT Generic Mapping Tools

GPS global positioning system

GulfCet Gulf of Mexico Cetacean Study

IAGC International Association of Geophysical Contractors

ID identifier for cruises

IFAW International Fund for Animal Welfare

ITM Information Transfer Meeting

LATEX Louisiana-Texas Shelf Physical Oceanography Program

LC Loop Current

LCE Loop Current eddy

MCS middle continental slope

MMS Minerals Management Service, U.S. Department of the Interior

mtDNA mitochondrial DNA

M/V Marine Vessel

NASA National Aeronautics and Space Administration

NAMSC North Atlantic and Mediterranean Sperm Whale Catalogue

NEGOM Northeastern Gulf of Mexico Physical Oceanography Program

NMEA National Marine Electronic Association, standard protocol for GPS receivers 

to transmit data

NMFS National Marine Fisheries Service (now NOAA Fisheries)

NMNH National Museum of Natural History

NOAA National Oceanic and Atmospheric Administration

NODC National Oceanographic Data Center

NOPP National Oceanographic Partners Program

NVODS National Virtual Ocean Data System

OCS outer continental shelf

OSU Oregon State University

ONR Office of Naval Research

PC personal computer

PCR polymer chain reaction

PDF portable document format
xiv

ACRONYMS

(continued)

Photo-ID photographic identification

PI Principal Investigator

PTT platform terminal transmitter

QA/QC quality assurance/quality control

RDI RD Instruments, Inc.

RHIB rigid-hulled inflatable boat

RL received level

R/V research vessel

SAIC Science Applications International Corporation

SAIL Serial ASCII Interface Loop

SeaWiFS Sea-viewing Wide Field-of-view Sensor

SIO Scripps Institution of Oceanography

SSH sea surface height

SST sea surface temperature

S-tag satellite-tracked radio tag

SWAMP Sperm Whale Acoustic Monitoring Program

SWSS Sperm Whale Seismic Study

TAMU Texas A&M University

TAMUG Texas A&M University-Galveston

TAMRF Texas A&M Research Foundation

T/E TAMUG/Ecologic

TIROS television infrared observational satellite

UD University of Durham, UK

UHF Ultra-High Frequency

UK United Kingdom

UNCW University of North Carolina, Wilmington

USF University of South Florida

UTC Universal Coordinated Time

VHF Very High Frequency

WHOI Woods Hole Oceanographic Institution

WSE warm slope eddy

XBT expendable bathythermograph probe
1

1 EXECUTIVE SUMMARY

1.1 Introduction

The Sperm Whale Seismic Study (SWSS) is supported by the Minerals Management Service

(MMS) of the U.S. Department of the Interior under Cooperative Agreement 1435-01-02-CA85186 for Cooperative Research on Sperm Whales and their Response to Seismic Exploration in

the Gulf of Mexico through the Texas A&M Research Foundation. Under SWSS, scientists from

Ecologic, Oregon State University (OSU), Scripps Institution of Oceanography (SIO), Texas

A&M University (TAMU), Texas A&M University-Galveston (TAMUG), University of

Colorado (CU), University of Durham, and Woods Hole Oceanographic Institution (WHOI)

develop and conduct the scientific research plans in coordination with MMS, the Office of Naval

Research (ONR), and the International Association of Geophysical Contractors (IAGC).

SWSS is being conducted from April 2002 through April 2005. The study consists of three years

of field research with analysis and synthesis. The study area is primarily the northern Gulf of

Mexico offshore of the 200-m isobath between DeSoto Canyon in the east and off-shelf of

Galveston in the west.

The objectives of SWSS are to

(1) establish the "normal" behavior of sperm whales in the northern Gulf of Mexico,

(2) characterize habitat use, and

(3) determine possible changes in behavior of sperm whales when subjected to man-made

noise, particularly from seismic airgun arrays.

In addition to program management, SWSS consists of six components: S-tag, D-tag, genetic

analyses, habitat characterization, passive acoustics, and photo identification/surface behavior

research. MMS provides fiscal support, project oversight, and cruise participants under this

Cooperative Agreement. ONR provides funding for development of both the S-tags and D-tags

used in this study. IAGC provided the seismic source vessel and its crew for the controlled

exposure experiment in the first field year. Contributions for field year 2 and tentatively for year

3 will expand from the IAGC to a broader industry coalition (including British Petroleum,

ChevronTexaco, ConocoPhillips, ExxonMobil, and Shell) and will include the addition of the

National Science Foundation as a supporting federal agency through Lamont Dougherty Earth

Observatory (LDEO).

The S-tag component is designed to evaluate the seasonal distribution of sperm whales in the

Gulf of Mexico. Sperm whales have been sighted in the Gulf of Mexico throughout the year, but

little is known about their numbers, site tenacity, and seasonal movements. Under the S-tag

component, up to 20 whales per year will be tagged in the northern Gulf of Mexico with a

satellite-tracked radio tag (S-tag) that will provide long-term (months) information on surfacing

locations of the tagged individuals. Tracking by satellite will be used to help identify behaviors,

summer and other seasonal habitats, and, in coordination with the habitat characterization task,

associations with oceanographic features.

The D-tag component is designed to quantify diving behavior and vocalizations in Gulf sperm

whales and to conduct controlled exposure experiments to measure reactions of these whales to

airgun sounds. A digital acoustic tag (D-tag) will be applied to individual whales to provide

intensive, short-term (hours) information on whale swimming behavior and to record underwater

noise both from the whale and received noise from the environment. The tag records the sounds

heard and made by the tagged whale, together with its depth and orientation (pitch, roll, and

heading), in a synchronized fashion throughout the dive cycle. Intensive visual and acoustic
2

observations from a nearby research vessel record the social and geographical context of the

whales' behavior, before, during, and after tagging. From a baseline understanding of expected

sperm whale behavior and preferred habitat, some whales will be tagged with the D-tag and then

exposed to sound sources from a seismic vessel provided by IAGC or to other sound sources,

such as recorded whale codas.

The genetic analyses component will allow study of groups of sperm whales in terms of

relatedness through DNA analyses of skin/tissue samples. Skin and biopsy samples will be taken

during the S-tag and D-tag cruises. The genetic analyses will investigate patterns of genetic

structure at three hierarchical levels: 1) social structure within and between groups and clusters;

2) phylogeographic structure among putative populations within the Gulf; and 3)

phylogeographic structure on a global scale incorporating SWSS results with those of previously

published studies with a particular focus on incorporating samples collected in the Caribbean

Sea, Atlantic, and Mediterranean Sea regions.

The habitat characterization component will merge biological oceanography, physical

oceanography, and remote sensing data to provide an interdisciplinary description of the

oceanographic habitat in which sperm whales are encountered.

Visual observations of surface behavior will be coupled with passive acoustic studies of

underwater activities of the whales. Passive acoustics will allow the SWSS team to find and

follow whales, even at nighttime when visual observations are not made. Photographic

techniques will be used to identify individuals and measure their lengths. These techniques will

allow improved estimates of the size of the sperm whale population that uses the area south of

the Mississippi River Delta and evaluations of their "usual" behavior, their site fidelity, and their

population structure.

In addition to its critical support of the tagging and survey efforts by enabling the SWSS team to

find and follow sperm whales, passive acoustic experiments will include methods to estimate

whale locations underwater from their sound sources (3-D passive acoustics), use of click

intervals to estimate whale size, and evaluation of codas for behavioral analyses.

1.2 Field Measurements

The 2002 field work consisted of the SWSS field cruise in two legs aboard the R/V Gyre and

follow-up cruises from small fishing vessels. The first leg was the S-tag cruise in June/July. This

was followed by the D-tag cruise in August/September. The S-tag follow-up cruises were in

December 2002 and February 2003. All activities associated with sperm whales are conducted

pursuant to approved permits from the National Marine Fisheries Service (now NOAA

Fisheries).

The S-tag leg of the SWSS 2002 cruise surveyed for whales along the middle continental slope

of the north central Gulf of Mexico between 94.7°W to 86.4°W from 19 June through 9 July

2002. Eighteen sperm whales were tagged with satellite transmitting tags. This will significantly

enhance our knowledge of the long term distribution of sperm whales in the Gulf of Mexico as

the data reveal information on whale locations over the year. Tagging was done between the

western edge of the Mississippi Canyon and DeSoto Canyon, with the majority of the tags

applied south and southeast of the Mississippi Delta. Biopsy sampling during the satellitetagging cruise also exceeded all expectations. Skin and blubber samples from fifteen of the

eighteen S-tagged sperm whales were obtained with sterilized darts. In all, a total of twenty-five

skin samples were collected. Sixty-five good quality (Q3) identification photographs were

taken during the cruise allowing the identification of 43 different individuals. Each day's photos

were matched against a set of approximately 2500 photos of sperm whale flukes in the North

Atlantic and Mediterranean Sperm Whale Catalogue; but, no matches were found with whales of
3

either the North Atlantic, the Mediterranean, or the Caribbean Sea. Nine matches were found

with the existing Gulf of Mexico Catalogue (1994-2001, 58 individuals).

Remote sensing images of sea surface height, ocean color, and sea surface temperature were

obtained for the time before and during the S-tag cruise. Five CTD stations were made. Thirtyfive expendable bathythermographs were dropped to profile temperature in the upper 760 m, and

seven supplemental drops were made to collect additional data from the upper 200 m. Nearsurface water was pumped from the ship's hull depth of 3.5 m through SeaBird temperature and

conductivity sensors and a Turner Designs Model 10 fluorometer to log sea surface temperature,

salinity, and chlorophyll fluorescence approximately once per minute. To provide calibration

data for the fluorometer data, 82 water samples from the flow-through stream were collected and

filtered. Ocean current velocity in the upper 300 m was monitored continuously with a hullmounted 153-kHz acoustic Doppler current profiler (ADCP).

The D-tag leg of the SWSS 2002 cruise was conducted from 19 August through 15 September

2002. The study was conducted between the 700-m and 1500-m isobaths, mainly on or near the

1000-m isobath, between 93°W and 88°W in the northern Gulf of Mexico. Two vessels were

involved in the D-tag field program. The science vessel was the R/V Gyre, which was staged out

of Galveston, TX, for the entire period of the cruise. The seismic source vessel was the Atlas

Boats vessel, Rylan T., with the Fairfield Industries seismic vessel, Speculator, mounted on the

back deck of the Rylan T. The IAGC provided the funding for the seismic source vessel and its

technical support crew for the period 29 August through 13 September 2002 in support of the Dtag controlled exposure experiment. Additionally, Seamap Inc. contributed a prototype passive

acoustic system for use on the Rylan T.

Despite lost days due to delays and weather, the experiments were an unqualified success.

Nineteen sperm whales were tagged. All tags were recovered yielding over 77 hours and 14

Gbytes of digital data. Fourteen animals completed at least one dive before the tag came off. A

total of 65 deep dives were recorded. Several notable events occurred including the longest D-tag

deployment to date (15 hrs, during which recordings were successfully made for 12.36 hours), a

synchronized dive by a pair of tagged whales, and three whales tagged at the same time. Foreign

whale codas were played to tagged animals. Two controlled exposure experiments of whales to

an operating seismic vessel were achieved, including one with three simultaneously tagged

whales. Seventeen fluke photographs were taken of 13 animals for photo-identification and three

frame-sets (measured length of animals) were made. Fourteen sperm whale skin samples were

collected, eleven from D-tag suction cups, one from biopsy sampling equipment, and two using a

dipnet to collect sloughed skin floating in the water. The visual team enjoyed 13 days of good

visual working conditions and the acoustics team recorded data on 20 of 25 days from two

hydrophone arrays aboard the Gyre, as well as numerous days from the array aboard the Rylan

T./Speculator.

Thirty-eight expendable bathythermograph probes were dropped, eight CTD casts were taken,

and chlorophyll concentrations were measured from 75 water samples. Continuous vertical

profiles of horizontal currents were collected from 153-kHz and 38-kHz ADCPs whenever

whales were not present, and continuous near-surface measurements of temperature, salinity, and

fluorescence were recorded whenever the vessel was underway. Remote sensing images of sea

surface height, ocean color, and sea surface temperature were obtained for the time before and

during the cruise.

1.3 Instruments and Data Methods

Three rigid hulled inflatable boats were launched from the research vessel, R/V Gyre, to tag and

photograph whales. These were two tag boats, the 24' MMS R2 and the 6.4-m OSU Puffin, used
4

for tagging activities on the S-tag and D-tag legs, as well as one supporting boat, the Gyre's 14'

Avon, used for S-tag support work and photo-identification.

On both cruises, whales were located and followed by a combination of visual and passive

acoustic means. Passive acoustics involved the monitoring of one or two towed hydrophones

round the clock for whale vocalizations by a four-person acoustic monitoring team. This enabled

the finding and following of sperm whales, as well as being a source of information on the

behavior of sperm whales and of responses. A visual observation station was established at the

highest, unobstructed point possible on the ship, which on the Gyre was on the flying bridge. It

consisted of three stand-mounted BigEye binoculars and a data entry station. Visual observers

conducted surveys during daylight hours and also supported the tagging efforts by providing

information on whale locations to the tag boats.

On locating suitable whales, the tag boat was launched and whales were approached for tagging.

The S-tag consists of Telonics transmitters, housed in stainless steel cylinders (19 cm long by 1.9

cm in diameter). They are designed for nearly complete implantation beneath the whale’s skin.

They are applied with an air-powered applicator from the tag boat. The tags transmit ultra-high

frequency radio signals to the Argos Data Location and Collection System receivers on the

National Oceanic and Atmospheric Administration television infra-red observation satellite

(TIROS)-N weather satellites. The whale locations are determined and used to study the

distribution and large-scale behavior of the whale.

The D-tag is a non-invasive tag that records the sounds heard and made by the tagged whale,

together with its depth and orientation (i.e., pitch, roll, and heading), in a synchronized fashion

throughout the dive cycle. The tag records data digitally for between 10 and 24 hours, depending

on sampling rate, with enough resolution to track individual fluke strokes. The D-tag is cast in

epoxy for robustness and is attached to the whale with suction cups. A 40' long cantilevered-pole

is used to deliver the tag to the whale, minimizing the impact of tagging. Intensive visual and

acoustic observations from a nearby research vessel record the social and geographical context of

the whales' behavior, before, during, and after tagging. These data are used to measure the sound

exposure levels received by a target animal under baseline conditions and during controlled

exposure experiments and to document and study its reaction.

The report contains details on these methods, as well as on methods for genetic typing, photoidentification, and habitat characterization.

1.4 Technical Summary

On 16-17 January 2003, the SWSS scientists, MMS managers, and other interested parties met in

New Orleans, LA, to discuss plans for the 2003 SWSS field program. Reviews of SWSS and the

Sperm Whale Acoustic Monitoring Program (SWAMP; a pilot study conducted in 2000 and

2001) preliminary results were given as background for that meeting and as part of the MMS

Information Transfer Meeting (ITM) on 15 January 2003. Synopses of the reviews presented at

the ITM are given. These include discussion of sperm whales in the Gulf of Mexico form photoidentification, photogrammetry, acoustic analyses, and observations of medium-scale

movements; identifying the seasonal distribution of sperm whales in the Gulf of Mexico with

satellite-monitored radio tags; analysis of sperm whale vocalizations from a towed passive

acoustic array; synopsis of diving behavior of D-tagged sperm whales; the molecular ecology of

sperm whales in the northern Gulf of Mexico; ship and satellite studies of sperm whale habitat;

and tracking responses of sperm whales to experimental exposures of airguns.
5

2 INTRODUCTION

The Sperm Whale Seismic Study (SWSS) is supported by the Minerals Management Service

(MMS) of the U.S. Department of the Interior under Cooperative Agreement 1435-01-02-CA85186 for Cooperative Research on Sperm Whales and their Response to Seismic Exploration in

the Gulf of Mexico. This report describes the SWSS program and participants and summarizes

the data collection and analysis efforts during year 1 of the study.

2.1 SWSS Background and Objectives

MMS has two core responsibilities in managing the Outer Continental Shelf (OCS) activities:

safe offshore operations and environmental protection. As part of its environmental

responsibilities, MMS seeks "to ensure that all activities on the OCS are conducted with

appropriate environmental protection and impact mitigation" (MMS, 2002). Oil and gas activities

in the deepwater Gulf of Mexico have increased over the last decade and are projected to

continue to increase in coming years. As these activities move into deep water, potential

increases for them to occur in regions frequented by the endangered sperm whale.

In 1999, MMS hosted a Gulf of Mexico Protected Species Workshop (McKay et al., 2001). The

purpose was to review past research, evaluate new issues, and recommend research priorities. A

panel of experts identified the potential effects of noise from seismic operations on sperm whales

as a key research priority. MMS, the Office of Naval Research (ONR), and the National Marine

Fisheries Service (NMFS) sponsored the Sperm Whale Acoustic Monitoring Program

(SWAMP), which was conducted in fiscal years 2000 and 2001 under the MMS Interagency

Agreement No. 15958. SWAMP was a pilot study that developed methods and began

documenting a baseline on "usual" behavior of sperm whales in the Gulf of Mexico. This study,

as well as earlier survey results, indicated that sperm whales tend to be most likely observed near

the 1000-m isobath (MMS, 2002). This Interagency Agreement expired on 30 September 2001.

During the January 2002 MMS Information Transfer Meeting, the International Association of

Geophysical Contractors (IAGC) hosted a meeting to discuss future acoustic research relevant to

seismic operations, and in particular, as related to understanding the effects of seismic

exploration on sperm whales in the Gulf of Mexico. IAGC offered its support for sperm whale

research through contribution of a seismic source vessel for controlled exposure experiments. In

response, the study entitled Cooperative Research on Sperm Whales and their Response to

Seismic Exploration in the Gulf of Mexico was proposed, under the auspices of the Texas A&M

Research Foundation (TAMRF), to the MMS. It was approved by MMS in April 2002. The

Cooperative Agreement was finalized in June 2002.

Under the terms of the June 2002 Cooperative Agreement, SWSS is being conducted from April

2002 through April 2005. The study consists of three years of field research with analysis and

synthesis to be completed in the fourth year. The study area is primarily the northern Gulf of

Mexico (Figure 2.1), with focus on the region immediately off the Mississippi River Delta. The

objectives of SWSS are to

(1) establish the "normal" behavior of sperm whales in the northern Gulf of Mexico,

(2) characterize habitat use, and

(3) determine possible changes in behavior of sperm whales when subjected to man-made

noise, particularly from seismic airgun arrays.

The primary noise source being evaluated is from airgun arrays used for offshore petroleum

exploration.
6

98°W 96°W 94°W 92°W 90°W 88°W 86°W 84°W 82°W 80°W

20°N

22°N

24°N

26°N

28°N

30°N TX LA

Mississippi

Delta Mississippi Canyon

MississippiAlabama

Shelf DeSoto Canyon

W

Florida Escarpment

est Florida Shelf

Sigsbee Escarpment

Sigsbee Plain

East Mexico Shelf

Bay of Campeche

Campeche Canyon

Yucatan Shelf

Campeche Bank

YUCATAN

PENINSULA

MEXICO

CUBA

FL

Campeche Escarpment

Yucatan Channel

Straits of Florida

Caribbean Sea

Texas-Louisiana Shelf

3000

2000

1000

200

Galveston

Figure 2.1. Bathymetry and geographical locations in the Gulf of Mexico. The study area was

centered about the 1000-m isobath (bold line) approximately between 95°W and

86°W, with a focus between the Mississippi and De Soto canyons.

2.2 Program Participants and Activities

SWSS involves personnel from many groups, including academic and MMS scientists and IAGC

engineers. The principal academic scientists are from Ecologic, Oregon State University (OSU),

Scripps Institution of Oceanography (SIO), Texas A&M University (TAMU), Texas A&M

University-Galveston (TAMUG), University of Colorado (CU), University of Durham (UD), and

Woods Hole Oceanographic Institution (WHOI). They develop and conduct the scientific

research plans in coordination with MMS, ONR, and IAGC. Table 2.1 identifies these scientists

and the tasks for which they are responsible.

In addition to providing funding for SWSS, MMS has substantial direct involvement under this

Cooperative Agreement. MMS scientists are actively involved in project oversight and

coordination of study activities with academic scientists, ONR, and IAGC, as well as other

offshore industry groups. They participate in the cruises on the visual and acoustic teams.

They coordinate the Information Transfer Meeting and internal planning sessions on sperm

whales and the SWSS project. Finally they are involved in public outreach related to Gulf of

Mexico marine mammals. MMS also is the lead agency for funding and decisions on program

activities.
7

Table 2.1

Major tasks by academic scientists in SWSS

Task Description Principal Investigators

Program Management Management of the program,

including scientific, operational,

and fiscal; oversight of preparation

of deliverables; data management,

including data archival

A. Jochens, TAMU,

 Program Manager

D. Biggs, TAMU,

 Project Scientist

M. Howard, TAMU,

 Data Manager

S-tag Study S-tag logistics, data collection,

data analysis, and reporting for Stag work

B. Mate, OSU, PI

D-tag Study D-tag logistics, data collection,

data analysis, and reporting for Dtag work

P. Tyack, WHOI, PI

M. Johnson, WHOI, co-PI

P. Miller, WHOI, co-PI

Genetic Analyses Skin and biopsy sampling, genetic

analyses for group relatedness,

and reporting

D. Engelhaupt, UD, PI

Habitat Characterization Habitat characterization logistics,

data collection, data analysis, and

reporting for physical and

biological habitat characterization

D. Biggs, TAMU, PI

A. Jochens, TAMU, co-PI

R. Leben, CU, co-PI

Passive Acoustics Acoustic monitoring, data

analysis, and reporting

J. Gordon, Ecologic, PI

A. Thode, SIO, PI

Photo Identification/Surface

Behavior

Photography and surface

observations

J. Gordon, Ecologic, co-PI

N. Jaquet, TAMUG, co-PI

B. Würsig, TAMUG, co-PI

IAGC provided the seismic source vessel and crew in the first field year. For year 2 and

presumably year 3, the IAGC will join a broader industry coalition that will provide similar or

greater contributions. The seismic source vessel is a critical contribution to the D-tag effort

because it allows controlled exposure experiments with sound from air-guns. IAGC also is

working with the industry to develop protocols for reporting operational seismic source vessel

locations and related information to SWSS academic scientists for use in the study. SEAMAP,

Inc. contributed a hydrophone array for the seismic source vessel in year 1.

ONR provides funding for development of both the S-tags and D-tags used in this study. It also

contributed resources, in the form of expendable bathythermographs (XBTs), for the habitat

characterization effort to measure the thermal structure that is important for the acoustic and

physical investigations in the study area.

In year 2 and anticipated for year 3, the National Science Foundation will provide support

through grant support to Lamont Dougherty Earth Observatory (LDEO) for use of the R/V

Maurice Ewing in D-tag work for SWSS. Coordinated efforts with LDEO to calibrate academic

and industry air-gun arrays also are planned.
8

In addition to program management, SWSS consists of six components: S-tag, D-tag, genetic

analyses, habitat characterization, passive acoustics, and photo identification/surface behavior

research. These, together with the principal investigators, are listed in Table 2.1. All activities are

conducted pursuant to approved permits from NMFS.

The S-tag task is designed to evaluate the seasonal distribution of sperm whales in the Gulf of

Mexico. Sperm whales have been sighted in the Gulf of Mexico throughout the year, but little is

known about their numbers, site tenacity, and seasonal movements. Under the S-tag task, up to

20 whales per year will be tagged in the northern Gulf of Mexico with a satellite-tracked radio

tag (S-tag) that will provide long-term (months) information on surfacing locations of the tagged

individuals. Tracking by satellite will be used to help identify behaviors, summer and other

seasonal habitats, and, in coordination with the habitat characterization task, associations with

oceanographic features.

The D-tag task is designed to quantify diving behavior and vocalizations in Gulf sperm whales

and to conduct controlled exposure experiments (CEEs) to measure reactions of these whales to

air-gun sounds. A digital acoustic tag (D-tag) will be applied to individual whales to provide

intensive, short-term (hours) information on whale swimming behavior and to record underwater

noise both from the whale and received noise from the environment. The tag records the sounds

heard, and made, by the tagged whale together with its depth and orientation (i.e., pitch, roll, and

heading), in a synchronized fashion throughout the dive cycle. Intensive visual and acoustic

observations from a nearby research vessel record the social and geographical context of the

whales’ behavior, before, during, and after tagging. From a baseline understanding of expected

sperm whale behavior and preferred habitat, some whales will be tagged with the D-tag and then

exposed to sound sources from a seismic vessel provided by IAGC or to other sound sources,

such as whale codas, using playback recordings.

The genetic analyses tasks will allow study of groups of sperm whales in terms of relatedness

through DNA analyses of skin/tissue samples. Skin and biopsy samples will be taken during the

S-tag and D-tag cruises. The genetic analyses will investigate patterns of genetic structure at

three hierarchical levels: 1) social structure within and between group and clusters; 2)

phylogeographic structure among putative populations within the Gulf; and 3) phylogeographic

structure on a global scale incorporating SWSS results with those of previously published studies

with a particular focus on incorporating samples collected in the Caribbean Sea, Atlantic, and

Mediterranean Sea regions.

The habitat characterization task merges methodologies from biological oceanography, physical

oceanography, and remote sensing to provide an interdisciplinary description of the

oceanographic habitat in which sperm whales are encountered. As part of the S-tag and D-tag

cruises, physical oceanographic and biological data observations are made. At sea measurements

include Conductivity-Temperature-Depth (CTD) profiles, expendable bathythermograph (XBT)

profiles, current measurements from a 153-kHz acoustic Doppler current profiler (ADCP) and a

38-kHz ADCP, near-surface underway temperature and salinity from a thermosalinograph, and

continuous near-surface chlorophyll using a calibrated flow-through fluorometer. Navigation

data and station locations are determined using differential Global Positioning System (GPS).

Additional Gulf-wide information includes sea surface height fields from satellite altimetry, sea

surface temperature fields from satellite AVHRR, and ocean color fields from SeaWiFS.

Visual observations of surface behavior will be coupled with passive acoustic studies of

underwater activities of the whales. The passive acoustics will allow the SWSS team to find and

follow whales, even at nighttime when visual observations are not made. In addition to visual

observations of surface behavior, photographic techniques will be used to identify individuals

and measure their lengths. These techniques will allow the improved estimates of the size of the
9

sperm whale population that uses the area south of the Mississippi River Delta and evaluations of

their "usual behavior", their site fidelity, and their population structure.

In addition to providing critical support of the tagging and survey efforts, passive acoustic

experiments will include methods to estimate whale locations underwater from their sound

sources (3-D passive acoustics), use of click intervals to estimate whale size, and evaluation of

codas for behavioral analyses.

During the three years of SWSS, field activities will occur mainly during late spring through

early fall, with a small component in winter to follow-up on S-tags. The field effort in year 1

consisted of the S-tag cruise (SWSS Leg 1, in June/July 2002), the D-tag cruise (SWSS Leg 2, in

August/September 2002), and the follow-up S-tag observations off Louisiana in December 2002

and January 2003 (Table 2.2). The Leg 1 and 2 cruises were aboard the R/V Gyre, operated by

the TAMU Department of Oceanography. The S-tag follow-up cruises were on fishing vessels

out of Venice, LA.

2.3 Report Organization

This is the first annual report of SWSS. It reports on the data-gathering efforts, equipment,

measurement and analytical methodologies employed; results of quality control exercises and

determinations; status of data archiving and data sharing; and preliminary data analysis and

results of the various data types collected. There are no extensive analyses or syntheses of the

information; such will be provided in the final Synthesis Report at the conclusion of SWSS.

Section 1 of this report is the executive summary. Section 3 details the data acquisition of the tag

measurements, visual and acoustic observations, genetic samples, and physical and biological

oceanographic data. Section 4 discusses instrumentation and data quality and analysis for the

observations collected, including data processing efforts and data quality control methods and

results. In Section 5 is presented brief technical discussion of the data, with samples of data

products for the various data types. All times are reported in Universal Coordinated Time (UTC)

unless stated otherwise. References are provided in Section 6.

Table 2.2

 Cruise leg identifiers and dates

Leg No. Start Date End Date SWSS ID Cruise ID

1 19 June 2002 9 July 2002 S-tag 02G08

2 19 August 2002 15 September 2002 D-tag 02G11

6 December 2002 8 December 2002 S-tag followup*

18 January 2003 2 February 2003 S-tag followup**

 * conducted from the fishing vessels Delta Dawn and Prime Time, out of Venice, LA

 ** conducted from the fishing vessel, Prime Time, out of Venice, LA
11

3 DATA COLLECTION CRUISES

Section 3 provides an overview of the SWSS data collection activities from April through

December 2002. It describes data gathering efforts on the cruises. Information on the

instrumentation and data processing procedures are given in Section 4.

The field cruises conducted in 2002 consisted of the SWSS field cruise in two legs aboard the

R/V Gyre and follow-up cruises from small fishing vessels. The first leg was the S-tag cruise in

June/July. This was followed by the D-tag cruise in August/September. The S-tag follow-up

cruises were in December. Additional S-tag follow-up cruises were conducted in January 2003,

but these will be reported on in the next annual report. Each cruise is described below.

3.1 S-tag Leg of SWSS 2002

The first leg of the 2002 field cruise was conducted on the R/V Gyre from 19 June through 9 July

2002. It was staged out of Galveston, TX, and ended in Gulfport, MS. Dr. Douglas C. Biggs of

TAMU was the Field Party Chief. Dr. Bruce R. Mate of OSU was in charge of S-tag activities.

Table 3.1.1 lists the cruise participants and their roles.

The S-tag field program was designed to find and tag sperm whales with satellite tags that would

enable monitoring of whale locations for up to a year to provide information on the distribution

and behavior of sperm whales in the Gulf of Mexico. Additionally, biopsy samples were

collected for genetic study, fluke photographs were taken for identification of individual sperm

whales and to augment the existing database of fluke photographs from Gulf of Mexico sperm

whales, and physical and biological measurements were made for sperm whale habitat

characterization.

Operations were conducted generally in accordance with the S-tag cruise plan of 7 June 2002.

On leaving Galveston, TX, the Gyre headed southward to approximately 94.7°W and the 1000-m

isobath. The cruise track is shown in Figure 3.1.1. The S-tag team then surveyed for sperm

whales along the middle continental slope to approximately 86.4°W. Although the ship track was

centered on the 900-1000-m isobaths, the survey generally followed a zig-zag course between

water depths from 575-820 m to 1125-1430 m. Additionally, once the ship reached the region

near the mouth of the Mississippi River and east, the course of the track was largely dictated by

the locations of sperm whales and tagging activities.

Both passive acoustics and visual observations were used to search for sperm whales. One to two

hydrophones were towed continuously and monitored, usually day and night, for sperm whale

sounds. Over 400 hours of acoustic observations were made, yielding acoustic contacts with

sperm whales as shown in Figure 3.1.2a. Three pairs of BigEye binoculars were used during

daylight (generally 06:30 to 19:30 CDT) for spotting sperm whales. These were mounted on the

flying deck of the Gyre to provide an unobscured view from the highest deck on the ship. Over

200 hours of visual observations were made, resulting in the visual contacts and tracking as

shown in Figure 3.1.2b.

When constructed in 1973, the Gyre was not specifically designed to be a quiet ship, so when

towing Ecologic or WHOI arrays the Gyre engine noise and other ship noises limited the ability

of observers to hear whales unless animals were within a few kilometers. Nonetheless, most

encounters with whales were initiated acoustically. It soon became evident, on days when the

weather was favorable but whales had not been located by the Gyre, that the search effort could

be increased dramatically by dispatching either one, or both, of the rigid-hulled inflatable boats

(RHIBs) to monitor acoustically ahead or abeam of the Gyre, using directional hydrophones.
12

Table 3.1.1

 The SWSS 2002 cruise, Leg 1, S-tag science team

Description Person (Institutional affiliation)

Field Party Chief Doug Biggs (TAMU College Station)

Electronics Technicians Eddie Webb (TAMU College Station)

Paul Clark (TAMU GERG)

Deck Engineers Bill Green (TAMU Galveston)

Mike Fredericks (TAMU GERG)

S-tag Team Bruce Mate (OSU Newport) *

Mary Lou Mate (OSU Newport)

Ladd Irvine (OSU Newport)

Daniel Palacios (OSU Newport)

Visual Team Nathalie Jaquet (TAMU Galveston) *

Joel Ortega (TAMU Galveston)

Christoph Richter (Canada)

Will Rayment (New Zealand)

Jamie McKee (SAIC)

Erin LaBrecque (New Hampshire)

Larry Glickman (Oregon)

Acoustic Team Jonathan Gordon (Ecologic UK) *

Sarah Tsoflias (MMS New Orleans)

Ricardo Antunes (Madeira, Portugal)

Reuben Heule (Netherlands)

Dan Lewer (OSU Newport)

Photo ID Team Jonathan Gordon (Ecologic UK)

Nathalie Jaquet (TAMU Galveston)

Biopsy/Genetic Typing Dan Engelhaupt (Durham Univ UK)

Flow Through Fluorescence/CHL Alicia Salazar (TAMU College Station)

Videography ** Terry Ketler Productions (San Francisco)

 * Team Leader

** Complimentary Program, added at no cost to MMS since bunk space #24 was available

GERG is the Geochemical and Environmental Research Group at TAMU

When operated in this mode, the RHIBs greatly extended the effective acoustical swath. While

this RHIBs-as-acoustic-spotter-boats scenario had not been anticipated before this cruise, by the

midpoint of the cruise two omni-directional hydrophone systems were constructed using spare

equipment that was on hand. Use of these omni-directional hydrophones, along with use of one

of the directional hydrophones, allowed reasonably effective away-from-the-mother-ship

monitoring from the RHIBs.

In addition to acoustically monitoring for cetacean vocalizations, the presence of anthropogenic

noise also was noted. The Gyre's own engine and prop sound masked many sources of

anthropogenic noise, but seismic shots were a prominent part of the acoustic scene and were

detected at a number of the stations. Opportunistic acoustic monitoring from the RHIBs near

platforms and other rigs detected strong tonal sounds that may have resulted from drilling or

other anthropogenic operations.
13

95°W 94°W 93°W 92°W 91°W 90°W 89°W 88°W 87°W 86°W 85°W

26°N

27°N

28°N

29°N

30°N

31°N

1 13 14

15

16 17

18

19

20

21 2 22

23

24

25

26

27

28

29 3

30

31

32 4

33

34

35

36

37

38

39 40

41

42

43

5 44 45 46

47 48

49

50

51

52 53

54

Galveston

New Orleans

200 km Gulfport

Figure 3.1.1. S-tag cruise track (thick gray line) for June/July 2002. Location of CTD (circles),

T7 XBT (open squares), and T10 XBT (filled squares) stations during the cruise.

Depth contours are 200, 1000, 2000, and 3000 m.

Eighteen days were spent along the middle continental shelf. During that time, sperm whales

were encountered only when the ship was between 89.9°W and 87.1°W. Although there were

reports of sperm whales west of 89.9°W, none were encountered. The whales observed were

either individuals (two encounters with lone males) or in dispersed groups of 5 to more than 13

animals. Although most of the whales were seen in water depths of 900-1000 m, they also were

encountered in water depths both shallower (to 700 m) and deeper (to 1300 m).

Once sperm whales were located, the OSU tag boat, Puffin (RHIB-1), was lowered from the

Gyre into the sea. The tag boat then transited to the whales, keeping always within visual and

radio contact with the Gyre for safety. Whales were tagged using a compressed air tag delivery

system. Eighteen sperm whales were tagged with satellite transmitting tags. Sixteen of the tags

were fully deployed and so securely attached; the other two were 40-50% deployed. Figure

3.1.3a shows the locations at which the whales were tagged. Tagging was done between the

western edge of the Mississippi Canyon and DeSoto Canyon, with the majority of the tags

applied south and southeast of the Mississippi Delta. Table 3.1.2 shows the locations, dates, and

times of the tagging.

The air applicator system worked extremely well. In general, tags were placed within 6 inches of

the mid-line along the whale's back between the middle of the base of the dorsal fin and 18"

forward of the dorsal fin. This is an area that surfaces quite regularly and should provide good

numbers of uplink messages during satellite passes when whales are at the surface. High-speed

(fast shutter speed) video of each tag application revealed the causes of the two tags deploying

incompletely. This enabled appropriate adjustments in hardware and technique to be made in the

field. Both of the two incompletely deployed tags were well placed on the whales' backs, and

both had good antenna orientation.
14

Figure 3.1.2. Locations of (a) acoustic contacts with sperm whales and (b) visual contacts and

tracking of sperm whales during SWSS cruise Leg 1, S-tag, June/July 2002.

Bathymetry contours are 200, 1000, 2000, and 3000 m.

(a)

(b)

91 ̊W 90 ̊W 89 ̊W 88 ̊W 87 ̊W 86 ̊W 27 ̊N

28 ̊N

29 ̊N

30 ̊N

New Orleans

Gulfport

91 ̊W 90 ̊W 89 ̊W 88 ̊W 87 ̊W 86 ̊W 27 ̊N

28 ̊N

29 ̊N

30 ̊N

New Orleans

Gulfport
15

91 ̊W 90 ̊W 89 ̊W 88 ̊W 87 ̊W 86 ̊W 27 ̊N

28 ̊N

29 ̊N

30 ̊N

New Orleans

1 2

3

4-6

7-8 9 10

11

14 12-13

15-16

17

18

91 ̊W 90 ̊W 89 ̊W 88 ̊W 87 ̊W 86 ̊W 27 ̊N

28 ̊N

29 ̊N

30 ̊N

New Orleans

1 2

3

9

(a)

(b)

4-6

7-8

10-16

18 tagged whales

25 skin/biopsy samples

Gulfport

Gulfport

Figure 3.1.3. Locations where (a) sperm whales were tagged with satellite tags and (b) skin

samples were taken during S-tag, June/July 2002. The tag number is shown for

tagged whales. Bathymetric contours are 200, 1000, 2000, and 3000 m.
16

Table 3.1.2

 Locations, dates, and times of the tagging of sperm whales with S-tags

Latitude

(°N)

Longitude

(°W)

Date

(mm/dd/yyyy)

Time

(UTC)

Tag No. PTT

No.

28.0117 -89.6960 06/24/02 18:36 1 5660

27.9937 -89.9135 06/24/02 23:06 2 5654

29.2078 -87.1783 06/26/02 23:03 3 5648

28.9578 -88.1092 07/01/02 19:35 4 5685

28.9562 -88.1088 07/01/02 19:48 5 5650

28.9512 -88.1125 07/01/02 20:16 6 5726

28.9030 -88.0988 07/01/02 21:40 7 5725

28.9028 -88.0923 07/01/02 21:58 8 5647

28.8603 -88.5290 07/02/02 23:10 9 5678

28.7937 -88.8082 07/03/02 15:24 10 5719

28.7883 -88.7640 07/03/02 16:49 11 5709

28.8395 -88.6915 07/03/02 19:48 12 5670

28.8503 -88.6733 07/03/02 20:09 13 5720

28.8385 -88.6865 07/03/02 20:47 14 5655

28.8042 -88.6932 07/03/02 23:07 15 5669

28.8050 -88.6982 07/03/02 23:42 16 5701

28.7323 -88.9230 07/07/02 19:25 17 5710

28.7077 -88.9110 07/07/02 20:20 18 5649

The tags were set for a duty cycle that allowed them to transmit for 4 pre-selected hours every

third day for the first 54 days. Starting 5 days before the D-tag cruise, the tags started

transmitting 4 hours/day on a daily basis to provide the D-tag group with detailed information on

whale locations for cruise planning and operations. Following the D-tag cruise, satellite tags

were set to transmit 4 hours/day every fourth day. This duty cycle was selected to extend the

operational life of the tags to allow documentation of longer-range seasonal movements.

Argos orbits only last for maximum of 16 minutes overhead (10 minute average), while whales

dive for 40 minutes and are at the surface for only about 10 minutes between dives. Thus, on

average, whales are only at the surface and available to transmit for 20% of the time. It is not

unusual that many fully-functional tags will not be heard during any specific duty cycle.

Whales were encountered only infrequently during the first week of the cruise. During this first

week, tagging operations also were hampered with swells large enough to prevent launching

RHIB-1 because of risk of damage to its bow pulpit should either RHIB-1 or mother ship surge

during the over-the-side deployment of the RHIB-1. During week 2, when the eastern extremity

of DeSoto Canyon was being surveyed, calm weather did not coincide with whale sightings.

Good concentrations of whales were encountered during the third week of the cruise. On calm

weather days, up to 7 whales were tagged in a single day. Tags were applied in sea states up to

Beaufort 4, winds up to 15 knots, and swells up to 3 feet. Beyond these conditions, tag

application was impossible.
17

Immediately after tagging, an attempt was made to collect a biopsy sample using crossbow

propelled darts. The samples were small plugs of tissue taken from the underside of the flukes or

behind the dorsal hump. Samples were collected from both tagged and untagged whales.

Twenty-five samples were collected, 16 of which were from whales tagged with S-tags. Figure

3.1.3b shows the locations, and Table 3.1.3 lists the dates, locations, tag number if applicable,

group number, and the approximate number of whales in the group.

Biopsy sampling during the satellite-tagging cruise exceeded all expectations. Skin and blubber

samples from fifteen of eighteen individual sperm whales outfitted with OSU satellite tags were

obtained with sterilized darts. Although biopsy sampling and tagging operations were most

successful on sperm whales occupying deepwater areas throughout the Mississippi River

Canyon, samples also were collected from whales in the DeSoto Canyon (Table 3.1.3). During

tagging approaches, whales' sizes were estimated and a decision was made to either proceed with

tagging or switch to a biopsy-only approach for immature whales too small to tag. In all, a total

of twenty-five skin samples were collected during the S-tag cruise. Given the amounts collected

per biopsy, all tissue samples obtained are expected to provide more than ample material for all

genetic applications.

The combination of satellite tagging and genetic techniques will provide an in-depth examination

of sperm whales found in the northern Gulf of Mexico. Molecular sexing, microsatellites, and

mitochondrial DNA sequencing will provide a rich set of information that can be directly

integrated with the movements of satellite tagged whales. A biopsy sample was obtained from

multiple members of six groups. Several of these sampled individuals had satellite tags to match.

Degrees of relatedness will be tested between whales found within these groups, allowing us to

begin to answer questions such as how related and unrelated whales found within groups in the

northern Gulf of Mexico maintain long-term close associations over space and time. In an ideal

situation, one would attempt to sample all members that comprise a group. Given this year's

primary focus on the satellite tagging effort, this was not possible. While our resulting genetic

composition of groups may not portray an accurate representation of group structure for freeranging sperm whales found in the Gulf of Mexico, the benefits of combining biopsy sampling

and satellite tagging will supply numerous answers to previously unknown questions.

A second small boat, RHIB-2, was launched to support the RHIB-1 tag boat whenever sperm

whales were sighted. RHIB-2 was crewed by two and sometimes three members of the scientific

party who were experienced in driving small boats close to whales, tracking whales using a

directional hydrophone, and taking identification photographs. A directional hydrophone was

used from RHIB-2 to track whales acoustically. This provided fine-scale information on the

location of submerged whales, thus allowing the tag boat (RHIB-1) to be close to whales when

the animals surfaced. This proved to be very effective, and allowed both RHIBs and the Gyre to

stay close to groups of whales.

The RHIB-2 crew generally stayed close to RHIB-1 to take identification photographs of whales

once they were tagged. Identification photographs were taken using a digital EOS 1D Canon

Camera with a Sigma 100-300 mm telephoto lens. In addition, photo-ID images were taken from

RHIB-1 using a conventional SLR. Ranges to flukes were measured using Bushnell or Leica

laser range finders. This is one of the first times that a digital camera has been used to take sperm

whale photo-identification images. The system proved excellent. It offered many advantages

over traditional film photography, including the ability to take detailed sequences of each fluke

up and to review photographic data and maintain the photo-catalogue at the end of each working

day.
18

Table 3.1.3

Biopsy/genetic typing tissue samples collected during S-tag fieldwork

 (The sample number gives the date (yymmdd) followed by the consecutive number for multiple

samples taken on any given day (01 to 08). Samples from tagged whales are indicated.)

Sample

No.

Tag

No.

Group

No.

Approx. Number of Whales

in Area

Longitude

(°W)

Latitude

(°N)

02062401 1 8 -89.6690 28.0557

02062402 5660 1 8 -89.6960 28.0117

02062403 5654 1 8 -89.9135 27.9937

02062801 5648 2 8 -87.1783 29.2078

02070101 5685 3 15-20 -88.1092 28.9578

02070102 5650 3 15-20 -88.1088 28.9562

02070103 5726 3 15-20 -88.1125 28.9512

02070104 5725 3 15-20 -88.0988 28.9030

02070105 5647 3 15-20 -88.0923 28.9028

02070106 3 15-20 -88.0923 28.9028

02070201 5678 4 8 -88.4957 28.8660

02070202 4 8 -88.4777 28.8840

02070301 5719 5 6-11 -88.8082 28.7937

02070302 5709 5 6-11 -88.7640 28.7050

02070303 5670 5 6-11 -88.6915 28.8395

02070304 5720 5 6-11 -88.6733 28.8503

02070305 5 6-11 -88.6733 28.8503

02070306 5670 5 6-11 -88.6990 28.7993

02070307 5701 5 6-11 -88.6982 28.8050

02070308 5669 5 6-11 -88.6837 28.8078

02070601 6 6-8 -89.0502 28.4258

02070602 6 6-8 -88.9907 28.4447

02070701 7 14-16 -88.6653 28.7012

02070702 7 14-16 -88.8750 28.7417

02070801 8 6 -88.2387 28.9920

Each evening the day's photos were matched against a set of 2500 photos of sperm whale flukes

in the North Atlantic and Mediterranean Sperm Whale Catalogue (NAMSC) of fluke photos.

This was both to find possible matching photographs and also to test performance, ease of use,

clarity of the interface, and logic of the data handling procedures. On a dedicated photo-ID

project, such immediate information on the identity of individuals could be used to best direct

subsequent days' survey effort.

Forty-seven good quality (Q3) identification photographs were taken and 32 different

individuals were identified. Photo-identification of individual whales was not a priority during

the S-tag cruise and could only be conducted opportunistically, which explains the low number

of new whales identified. Prior to 2002, the Gulf of Mexico catalogue contained only 58

different individuals, so the 32 new individuals identified by RHIB-2 during the S-tag cruise

represents a significant contribution to the catalogue and to our knowledge of the Gulf of Mexico
19

sperm whale population. Furthermore, 18 good quality photographs (Q3) were taken by RHIB1 allowing the identification of another 11 different individuals. Four to five S-tagged sperm

whales were photo-identified. The main reason for the low success of the photo-identification

work was that sperm whales very rarely fluked after being tagged; additionally, due to the

proximity of many other whales, it was not possible to track the tagged whale acoustically during

an entire dive cycle.

The images have been contributed to the NAMSC. Table 3.1.4 gives the locations, dates, times,

and other pertinent information of the photos taken for photo-identification (51 total by the

TAMUG/Ecologic, or T/E, team including 4 resights of Q=2) and for the S-tagging process (20

total by the OSU team including 2 resights of Q=2). A map with locations is given in Figure

3.1.4.

Experience indicated that more tagged whales were successfully photo-identified, including tag

attachment photos, when RHIB-2 was used simply to take as many identification photographs of

as many whales as possible rather than when RHIB-2 operated exclusively in close proximity to

RHIB-1. The S-tag cruise experience also indicated that the use of one or more RHIBs with

support from a visual team equipped with BigEye binoculars operating from an elevated

platform on a mother vessel could be an effective way of collecting photo-ID material with Gulf

of Mexico sperm whales.

The opportunity to test beta versions of two new programs for automated photo-identification of

sperm whales was pursued on the S-tag leg. One program, temporarily named "Phlukes", assists

the user in extracting the identifying contour of the fluke from the photograph. The other

program, temporarily named "Match", finds contours similar to those of the target image from a

collection of contours previously extracted from a collection of photos. Both programs are

written in Java and are being developed within "Europhlukes", an EU-funded project under the

direction of Reuben Huele that will set up a European database of cetacean images.

All S-tag, photo-ID, and biopsy/genetic typing activities were conducted in accordance with

federal permits from the U.S. National Marine Fisheries Service to Oregon State University

(permit 365-1440-01), to Texas A&M University-Galveston (permit 821-1588-00), and to Dan

Engelhaupt/University of Durham (permit 909-1465-01).

In addition to observations of sperm whales, the cruise collected physical and biological

observations to allow characterization of the habitat. Sea surface height (SSH) fields were

obtained once per week before and during the cruise and used to identify circulation features

near the whales. Figure 3.1.5 shows the pre-cruise SSH field for 9 June 2002. It indicated that the

circulation over the middle continental slope would be cyclonic (counterclockwise) both west of

~92°W and east of ~89°W. It also indicated that an anticyclonic (clockwise circulation) warm

slope eddy was present between 92°W and 89°W, separating the two regions of cyclonic

circulation. This cyclonic-anticyclonic-cyclonic triad would tend to advect high salinity, low

chlorophyll, "blue" water onto the margin near 92°W and to entrain and transport low salinity,

higher chlorophyll, "green" water from the shelf off the margin near 89°W. Subsequent SSH

fields showed a similar configuration, although with some weakening of the cyclonic circulation

in the east. Data from the in situ stations (identified below) generally confirmed the circulation

pattern indicated by the SSH fields.

Five CTD stations were made. Thirty-five T7 XBTs were dropped to profile temperature in the

upper 760 m, and seven supplemental drops were made with T10 XBTs to collect additional data

from the upper 200 m. Figure 3.1.1 shows a map of the locations of the CTD and XBT stations.

Table 3.1.5 shows the locations, date, times, total water depth, and depth of the 15°C isotherm

for the CTD and XBT stations. Through the passive acoustic monitoring, sperm whales were

detected at or near about 25% of the CTD/XBT stations.
20

Table 3.1.4

Locations and dates of scientific photographs of sperm whales

(The teams taking the photographs were Oregon State University (OSU) for use in assessing

 S-tag success and Texas A&M University-Galveston and Ecologic (T/E) for use in photoidentification. The ID exposure is the reference number of the photograph. The Q value denotes

the quality of the picture following Arnbom 1987, with highernumbers indicating better quality.

The preliminary names given in plain text are the best photos for each individual and those in

italics are resights. Whale NN2 was identified as a male.)

Longitude

(°W)

Latitude

(°N)

Date Time of

Fluke Up

(CDT)

Photo

Team*

ID Exposure Q

value

Prelimi

-nary

Name

-89.6520 28.0945 06/24/2002 10:46 T/E 326 4 MTL 1

-89.6615 28.0587 06/24/2002 11:46 T/E 328 3 MTB 1

-89.6700 28.0600 06/24/2002 12:43 OSU Film 1/Exp 6 3 HR 4

-89.6952 28.0397 06/24/2002 12:46 T/E 333 2 HL 1

-89.8188 27.9998 06/24/2002 16:13 T/E 345 3 HL 1

-89.7318 28.0068 06/25/2002 14:41 T/E 356 3 HL 2

-89.7363 28.0022 06/25/2002 14:52 T/E 359 5 HR 1

-89.0993 28.1693 06/26/2002 09:36 T/E 367 5 MTB 2

-87.4507 29.2860 06/28/2002 11:04 T/E 385 3 SNB 1

-87.4273 29.2982 06/28/2002 11:40 T/E 392 5 HL 3

-87.3800 29.3000 06/28/2002 12:35 OSU Film 3/exp 13 2 HL 3

-87.3560 29.2873 06/28/2002 13:10 T/E 404 3 SNB 1

-87.3138 29.2672 06/28/2002 14:13 T/E 413 4 SNB 1

-87.2787 29.2512 06/28/2002 15:18 T/E 441 5 HL 3

-87.2100 29.2200 06/28/2002 17:05 OSU Film 3/Exp 28 4 SNR 6

-87.1800 29.2100 06/28/2002 18:13 OSU-Video T292AC~1 3 NN 4

-87.1802 29.1923 06/28/2002 18:14 T/E 477 4 MTL 2

-88.0742 28.9127 07/01/2002 12:16 T/E 618 2 MTR 1

-88.0875 28.9022 07/01/2002 17:13 T/E 636 3 MTR 1

-88.5513 28.7707 07/02/2002 14:14 T/E 732 4 SS 1

-88.5300 28.7800 07/02/2002 16:17 OSU Film 5/ Exp 15 3 SS 1

-88.5318 28.8612 07/02/2002 17:54 T/E 752 3 MTL 3

-88.5318 28.8612 07/02/2002 17:54 T/E 759 3 MTB 4

-88.4803 28.8978 07/02/2002 19:02 T/E 822 5 LNB 1

-88.4760 28.8988 07/02/2002 19:11 T/E 854 5 SNR 1

-88.4800 28.8800 07/02/2002 19:22 OSU Film 8/Exp 1 3 MTR 4

-88.7903 28.7522 07/03/2002 08:47 T/E 874 3 MTR 2

-88.7953 28.7635 07/03/2002 09:22 T/E 883 3 MTB 3

-88.7900 28.7700 07/03/2002 09:29 OSU-Video T4_7-0~1 3 HL 4

-88.7800 28.7800 07/03/2002 09:40 OSU Film 8/Exp 17 2 LNB 2

-88.8052 28.7970 07/03/2002 10:39 T/E 892 4 SNR 2

-88.8047 28.7978 07/03/2002 10:40 T/E 897 3 LNL 1

-88.7900 28.8000 07/03/2002 11:15 OSU Film 8/Exp 33 4 MTB 3

-88.7800 28.7900 07/03/2002 11:33 OSU Film 6/Exp 1 4 HL 4

-88.7675 28.7878 07/03/2002 11:46 T/E 901 4 MTR 2

-88.7643 28.7872 07/03/2002 11:52 T/E 913 4 LNB 2

-88.7705 28.7770 07/03/2002 12:21 T/E 923 2 MTB 3

-88.7500 28.7800 07/03/2002 12:18 OSU Film 6/Exp 8 3 HL 5

-88.7500 28.7800 07/03/2002 12:18 OSU Film 8/Exp 9 3 NN 3

-88.6600 28.8100 07/03/2002 13:26 OSU-Video T5_7-0~2 3 MTB 4

-88.6647 28.8193 07/03/2002 13:30 T/E 930 3 LSR 1

-88.6760 28.8240 07/03/2002 13:44 T/E 934 4 MTL 3
21

Table 3.1.4

Locations and dates of scientific photographs of sperm whales (continued)

Longitude

(°W)

Latitude

(°N)

Date Time of

Fluke Up

(CDT)

Photo

Team*

ID Exposure Q

value

Prelimi

-nary

Name

-88.6725 28.8373 07/03/2002 14:38 T/E 945 4 HR 2

-88.6935 28.8325 07/03/2002 15:18 T/E 952 3 LSR 1

-88.6700 28.8400 07/03/2002 15:40 OSU Film 7/Exp 5 3 MTB 5

-88.6708 28.8072 07/03/2002 16:37 T/E 974 5 NN 1

-89.4535 28.3317 07/04/2002 11:36 T/E 1031 4 NN 2*

-89.5317 28.2955 07/04/2002 14:03 T/E 1036 5 NN 2

-89.5733 28.2907 07/04/2002 15:24 T/E 1043 4 NN 2

-89.6632 28.2822 07/04/2002 17:47 T/E 1053 4 NN 2

-89.6997 28.2782 07/04/2002 18:49 T/E 1062 4 NN 2

-88.9974 28.3293 07/05/2002 10:58 T/E 1071 3 SNR 3

-89.0153 28.2985 07/05/2002 12:06 T/E 1128 2 SNR 3

-89.0600 28.2300 07/05/2002 14:43 OSU Film 9/Exp 25 3 HR 5

-89.0930 28.4185 07/06/2002 15:09 T/E 1283 3 SNR 4

-89.0500 28.4300 07/06/2002 16:20 OSU Film 9/Exp 28 3 SNL 1

-89.0300 28.4300 07/06/2002 16:47 OSU Film 10/Exp 3 3 SNL 2

-89.0200 28.4200 07/06/2002 17:09 OSU Film 10/Exp 9 3 LNL 2

-88.9842 28.4340 07/06/2002 18:11 T/E 1334 3 MTL 4

-88.6400 28.7100 07/07/2002 09:42 OSU Film 10/Exp 27 3 HR 2

-88.6400 28.7000 07/07/2002 10:01 OSU Film 10/Exp 31 3 MTB 4

-88.6677 28.6990 07/07/2002 10:26 T/E 1458 3 LSR 1

-88.7645 28.6892 07/07/2002 12:26 T/E 1476 4 HL 4

-88.9398 28.6770 07/07/2002 16:20 T/E 1527 3 MTL 4

-88.9293 28.6835 07/07/2002 16:45 T/E 1535 3 SNR 5

-88.9293 28.6835 07/07/2002 16:45 T/E 1546 5 LNR 1

-88.9382 28.6707 07/07/2002 17:26 T/E 1607 3 HR 2

* * 07/07/2002 18:20 T/E 1616 3 MTB 4

* * 07/07/2002 19:08 T/E 1625 5 LSR 1

-88.2095 28.8948 07/08/2002 10:03 T/E 1631 3 HR 3

-88.2440 28.9387 07/08/2002 13:12 T/E 1660 3 LSB 1

* Computer crash, so locations lost

Near-surface water was pumped from the ship's hull depth of 3.5 m through SeaBird temperature

and conductivity sensors and a Turner Designs Model 10 fluorometer to log surface temperature,

salinity, and chlorophyll fluorescence approximately once per minute. To provide data with

which to calibrate the flow-through fluorometer data, 82 water samples from the flow-through

stream were collected and filtered (Figure 3.1.6). The filters then were analyzed for chlorophyll

using extraction methods and a Turner Designs Model 10. Sixty-one samples were taken during

the S-tag cruise and twenty-one were taken after the cruise when Gyre was in transit from

Gulfport, MS, to Galveston, TX. Table 3.1.6 gives the locations, dates, times, fluorescence

values, and extracted chlorophyll values for these samples.

Ocean current velocity in the upper 300 m was monitored continuously with a hull-mounted 150

kHz ADCP. Figure 3.1.7 (upper) shows the locations with good 153-kHz ADCP data. Figure

3.1.7 (lower) shows processed current velocity vectors at the 13.6-m depth along the cruise track.
22

91°W 90°W 89°W 88°W 87°W 86°W

27°N

28°N

29°N

30°N

New Orleans

Figure 3.1.4. Locations at which photographs were taken for photo-identification during SWSS

cruise Leg 1, S-tag, June/July 2002. Dots denote photo-ID pictures; triangles

denote tagging pictures. Bathymetry contours are 200, 1000, 2000, and 3000 m.

A 38-kHz ADCP, which profiles down to approximately 900 m, also was operated continuously.

However, data obtained with the 38-kHz ADCP were not usable for several reasons, including

problems with instrument mounting, the ship's electrical system, and degraded instrumentation.

These problems and their correction for subsequent cruises will be discussed in more detail in

Section 4.
23

Figure 3.1.5. Sea surface height from TOPEX/ERS-2 altimeters for 9 June 2002. Image is from

Robert Leben, Colorado Center for Astrodynamics Research (CCAR), University

of Colorado.
24

Table 3.1.5

 Hydrographic stations on S-tag cruise

Station Date

(mm/dd/yyyy)

Time

(UTC)

Latitude

(°N)

Longitude

(°W)

Water

depth

(m)

15°C depth

(m)

CTD-01 06/20/2002 16:05 27.08 -94.68 1030 214

XBT-13 (T7) 06/21/2002 01:52 27.03 -94.16 1780 194

XBT-14 (T7) 06/21/2002 06:10 27.16 -93.67 1020 189

XBT-15 (T7) 06/21/2002 10:10 26.98 -93.24 1325 209

XBT-16 (T7) 06/21/2002 12:49 27.20 -93.03 1160 205

XBT-17 (T7) 06/21/2002 15:32 27.12 -92.75 1360 207

XBT-18 (T7) 06/21/2002 21:29 27.44 -92.53 920 218

XBT-19 (T7) 06/22/2002 01:09 27.20 -92.25 1430 193

XBT-20 (T7) 06/22/2002 06:21 27.57 -92.04 700 190

XBT-21 (T7) 06/22/2002 10:37 27.40 -91.69 1000 194

CTD-02 06/22/2002 13:55 27.55 -91.51 942 189

XBT-22 (T7) 06/22/2002 16:50 27.48 -91.24 1275 223

XBT-23 (T7) 06/22/2002 21:01 27.74 -90.88 925 245

XBT-24 (T7) 06/22/2002 23:20 27.56 -90.72 955 272

XBT-25 (T7) 06/23/2002 02:45 27.85 -90.52 660 258

XBT-26 (T7) 06/23/2002 06:05 27.61 -90.24 1000 300

XBT-27 (T7) 06/24/2002 00:39 27.88 -90.04 700 256

XBT-28 (T7) 06/24/2002 04:42 27.60 -89.69 1125 283

XBT-29 (T7) 06/24/2002 08:08 27.92 -89.53 1010 231

CTD-03 06/25/2002 01:06 28.00 -89.87 680 247

XBT-30 (T7) 06/26/2002 02:47 28.33 -89.60 840 212

XBT-31 (T7) 06/26/2002 07:42 28.15 -89.16 760 208

XBT-32 (T7) 06/27/2002 00:37 28.58 -89.01 575 224

CTD-04 06/27/2002 01:56 28.66 -88.91 990 214

XBT-33 (T7) 06/28/2002 19:40 29.27 -87.32 790 211

XBT-34 (T7) 06/29/2002 02:55 29.01 -87.10 830 228

XBT-35 (T7) 06/29/2002 05:34 28.75 -87.10 820 206

XBT-36 (T7) 06/29/2002 08:08 28.50 -87.00 860 210

XBT-37 (T7) 06/29/2002 10:42 28.29 -86.81 980 230

XBT-38 (T7) 06/29/2002 13:54 28.07 -86.52 1180 231

XBT-39 (T7) 06/29/2002 16:26 28.31 -86.43 715 225

XBT-40 (T7) 06/30/2002 06:09 28.31 -87.11 1330 222

XBT-41 (T7) 06/30/2002 09:32 28.62 -87.29 1150 186

XBT-42 (T7) 06/30/2002 14:05 29.08 -87.21 1000 228

XBT-43 (T7) 06/30/2002 15:24 29.21 -87.17 800 226

CTD-05 06/30/2002 20:52 29.27 -87.44 870 201

XBT-44 (T7) 07/01/2002 13:18 29.17 -87.77 1055 219

XBT-45 (T7) 07/01/2002 16:03 28.99 -87.94 1425 221

XBT-46 (T7) 07/02/2002 12:14 28.89 -88.17 1175 226

XBT-47 (T7) 07/02/2002 21:48 28.80 -88.52 1100 239

XBT-48 (T10) 07/03/2002 12:09 28.68 -88.62 1030 216

XBT-49 (T10) 07/04/2002 05:49 28.48 -88.98 927 217

XBT-50 (T10) 07/04/2002 07:58 28.26 -88.99 1210 216

XBT-51 (T10) 07/04/2002 13:42 28.28 -89.28 813 222

XBT-52 (T10) 07/05/2002 01:45 28.26 -89.70 775 218

XBT-53 (T10) 07/05/2002 10:52 28.46 -88.99 970 215

XBT-54 (T10) 07/08/2002 01:58 28.69 -88.96 790 211
25

91°W 90°W 89°W 88°W 87°W 86°W

27°N

28°N

29°N

30°N

New Orleans

Figure 3.1.6. Locations of water samples filtered and analyzed for chlorophyll during SWSS

cruise Leg 1, S-tag, June/July 2002. Dots denote samples used in regression with

fluorescence; triangles denote samples not used. Bathymetry contours are 200,

1000, 2000, and 3000 m.
26

Table 3.1.6

 Extracted chlorophyll stations on S-tag cruise

Station Date Time

(UTC)

Longitude

(°W)

Latitude

(°N)

Fluor

x 31.6

(mvolts)

Extracted

CHL

(ug/L)

Notes

CTD-01 06/20/2002 15:35 -94.683 27.140 171 0.18

XBT11 06/20/2002 18:03 -94.662 27.056 167 0.14

XBT12 06/20/2002 18:30 -94.685 27.002 157 0.12

survey 06/20/2002 19:56 -94.720 26.883 159 0.15

XBT13 06/21/2002 01:54 -94.160 27.034 147 0.10

XBT14 06/21/2002 06:14 -93.664 27.158 145 0.12

XBT15 06/21/2002 10:07 -93.251 26.987 152 0.15

XBT16 06/21/2002 12:52 -93.025 27.204 151 0.13

XBT17 06/21/2002 15:32 -92.746 27.119 151 0.13

XBT18 06/21/2002 21:22 -92.524 27.436 148 0.11

XBT19 06/22/2002 01:10 -92.245 27.199 145 0.11 1

XBT20 06/22/2002 06:22 -92.037 27.575 148 0.10

XBT21 06/22/2002 10:37 -91.693 27.403 150 0.14 1

CTD-02 06/22/2002 13:55 -91.514 27.549 145 0.13

XBT22 06/22/2002 18:08 -91.144 27.572 138 0.12

XBT23 06/22/2002 21:03 -90.881 27.735 144 0.10 1

XBT24 06/22/2002 23:21 -90.722 27.555 143 0.10 1

XBT25 06/23/2002 02:50 -90.509 27.857 143 0.12 1

XBT26 06/23/2002 06:06 -90.241 27.607 140 0.08

whales near 06/23/2002 19:30 -90.170 27.565 138 0.08

XBT27 06/24/2002 00:40 -90.034 27.879 141 0.13

XBT28 06/24/2002 04:30 -89.897 27.609 139 0.09

XBT29 06/24/2002 08:07 -89.534 27.924 142 0.13 1

XBT30 06/25/2002 02:45 -89.599 28.329 145 0.14

XBT31 06/26/2002 12:39 -89.102 28.225 141 0.12

XBT32 06/27/2002 00:30 -89.014 28.575 1540 6.96 3

CTD-04 06/27/2002 02:28 -88.905 28.660 1480 6.23 3

transit 06/27/2002 06:09 -88.813 29.167 690 3.35 2, 3

transit 06/27/2002 07:09 -88.809 29.311 1280 8.30 2, 3

transit 06/27/2002 09:12 -88.768 29.611 600 2.41 2, 3

transit 06/27/2002 11:01 -88.728 29.867 440 1.31 2, 3

transit 06/28/2002 04:17 -88.731 30.025 901 5.22 2, 3

transit 06/28/2002 05:58 -88.512 29.860 272 1.31 2, 3

transit 06/28/2002 07:05 -88.356 29.762 228 0.29

transit 06/28/2002 08:05 -88.223 29.677 165 0.18

transit 06/28/2002 09:16 -88.072 29.581 198 0.24

transit 06/28/2002 10:00 -87.975 29.522 199 0.29

transit 06/28/2002 11:07 -87.827 29.421 181 0.08 3, 4

transit 06/28/2002 12:01 -87.701 29.346 180 0.27

whales near 06/28/2002 16:40 -87.450 29.307 159 0.20

XBT34 06/29/2002 02:58 -87.097 29.009 164 0.18

XBT35 06/29/2002 05:37 -87.100 28.746 179 0.20

XBT36 06/29/2002 08:09 -87.000 28.499 182 0.21

XBT37 06/29/2002 10:49 -86.800 28.281 138 0.16 3

XBT38 06/29/2002 14:13 -86.503 28.093 139 0.21 3

XBT39 06/29/2002 16:26 -86.431 28.311 139 0.18 3

transit 06/29/2002 17:33 -86.553 28.319 130 0.14 3

XBT40 06/30/2002 06:09 -87.110 28.306 147 0.14 3

XBT41 06/30/2002 09:31 -87.285 28.616 184 0.29 3

XBT42 06/30/2002 14:12 -87.208 29.088 165 0.20 3

XBT43 06/30/2002 15:25 -87.170 29.212 160 0.26 3

CTD 5 06/30/2002 20:54 -87.439 29.273 171 0.21

XBT44 07/01/2002 13:17 -87.764 29.168 191 0.33

transit 07/01/2002 14:08 -87.816 29.115 378 1.42 3
27

Table 3.1.6

Extracted chlorophyll stations on S-tag cruise (continued)

Station Date Time

(UTC)

Longitude

(°W)

Latitude

(°N)

Fluor

x 31.6

(units?)

Extracted

CHL

(ug/L)

Notes

XBT45 07/01/2002 16:05 -87.940 28.997 235 0.41

whales near 07/01/2002 22:30 -88.091 28.908 230 0.35

XBT46 07/02/2002 12:13 -88.170 28.887 135 0.14

XBT47 07/02/2002 21:58 -88.524 28.812 135 0.15

XBT48 07/03/2003 13:29 -88.815 28.732 153 0.21

XBT50 07/04/2002 07:57 -88.987 28.257 133 0.13

XBT51 07/04/2002 13:49 -89.291 28.286 138 0.19 3

XBT53 07/05/2002 10:52 -88.992 28.457 139 0.19 3

XBT54 07/07/2002 01:02 -88.963 28.670 150 0.17 3

transit 07/08/2002 19:05 -88.250 29.003 173 0.44

transit 07/08/2002 19:59 -88.308 29.119 180 0.35

transit 07/08/2002 20:43 -88.350 29.199 202 0.39

transit 07/08/2002 21:10 -88.379 29.255 215 0.32

transit 07/08/2002 21:21 -88.392 29.279 232 0.39

transit 07/08/2002 21:30 -88.402 29.299 249 0.76

transit 07/08/2002 21:47 -88.421 29.337 284 0.43

transit 07/10/2002 05:00 -88.935 30.124 908 2.21 5

transit 07/10/2002 05:27 -88.872 30.092 756 1.81 5

transit 07/10/2002 05:55 -88.807 30.059 626 1.27 5

transit 07/10/2002 06:24 -88.773 30.002 424 0.80 5

transit 07/10/2002 06:39 -88.762 29.968 392 0.89 5

transit 07/10/2002 06:56 -88.748 29.929 288 0.39 5

transit 07/10/2002 08:11 -88.753 29.755 266 0.27 5

transit 07/10/2002 09:12 -88.745 29.611 525 1.18 5

transit 07/10/2002 10:27 -88.777 29.435 946 2.61 5

transit 07/10/2002 10:44 -88.778 29.393 1078 3.01 5

transit 07/10/2002 11:17 -88.801 29.313 1391 4.75 5

transit 07/10/2002 13:07 -88.848 29.041 405 1.25 5

Notes:

1 - fluorescence is estimated due to in-line bubbles

2 - only 500 ml was filtered

3 - not used in linear regression

4 - low CHL is an artifact of filtering too dry

5 - sample taken on post SWSS cruise from Gulfport, MS, to Galveston, TX; data used in linear regression
28

95°W 94°W 93°W 92°W 91°W 90°W 89°W 88°W 87°W 86°W

26°N 

27°N 

28°N 

29°N 

30°N 

31°N 

10m

20m

100m

200m

1000m

Texas Louisiana Mississippi Alabama Florida

10

20

100

200

1000

Texas Louisiana Mississippi Alabama Florida

100 cm·s -1

95°W 94°W 93°W 92°W 91°W 90°W 89°W 88°W 87°W 86°W 

26°N 

27°N 

28°N 

29°N 

30°N 

31°N 

Figure 3.1.7. ADCP data collection on S-tag cruise, 20 June - 8 July 2002. Shown are (upper)

the locations of 153-kHz ADCP-measured currents and (lower) the horizontal

current velocity at 13.6-m depth.
29

3.2 D-tag Leg of SWSS 2002

The second leg of the SWSS 2002 field cruise was conducted from 19 August through 15

September 2002. Two vessels were involved in the D-tag field program. The science vessel was

the R/V Gyre, which was staged out of Galveston, TX, for the entire period of the cruise. Dr.

Mark Johnson of WHOI was the Field Party Chief during the basic D-tag operations; Dr. Peter

Tyack of WHOI was Field Party Chief during the controlled exposure experiment (CEE). The

seismic source vessel was the Atlas Boats vessel, Rylan T., with the Fairfield Industries seismic

vessel, Speculator, mounted on the back deck of the Rylan T. The IAGC provided the funding

for the seismic source vessel and technical support crew for the period of the D-tag controlled

exposure experiment. Fairfield Industries arranged for the boat modifications and support

personnel under contract to the IAGC. Seamap Inc. contributed a prototype passive acoustic

system for use on the Rylan T., including hydrophone array, computers and associated software,

and technical team. The Rylan T. left Texas City, TX, on 29 August and rendezvoused with Gyre

on 31 August to begin the CEE. It departed the survey area on 11 September to return to port by

13 September 2002. Table 3.2.1 lists the cruise participants for both vessels and their roles.

The major goal of the D-tag experiment was to locate and tag sperm whales both for assessment

of normal behavior and then to monitor their behavior in the presence of controlled exposures to

specific sounds. Additional important goals were to collect skin and biopsy samples for genetic

study, to take photographs of flukes for identification of individuals, and to make oceanographic

measurements to characterize the marine habitat. The specific sounds to be presented included

foreign and familiar whale codas (called "playbacks") and sounds produced by airguns used in

marine seismic surveys. Monitoring included recording the time history of the tagged animal's 3-

D location, orientation (roll-pitch-heading), and any sounds produced by or impinging upon the

animal.

Mobilization for the D-tag cruise began on 18 August. The Gyre left the dock at 0200 CDT on

September 21, instead of September 19 as originally planned. This was mainly due to flooding

and bad weather in Galveston the week before, which delayed the completion and testing of the

custom launch ramp system for the 5000+ pound MMS R2 tag boat until the 19th and 20th.

Additionally, the OSU tag boat was outfitted with a back brace and mount for the tagging pole in

case this boat would be needed as a back-up; these were constructed and added to the boat just

before the cruise departed. Additional time was lost during the cruise due to two unforeseeable

events: a crew family emergency and an engine failure. A total of 3 days out of 28 were

effectively lost for the above reasons. A further 10 days were lost to poor weather leaving a total

of 15 days for the transit to and from Galveston and for the tagging project. Tagging was

attempted on 11 out of 13 fair weather days and tags were deployed on 10 days.

Despite lost days due to delays and weather, the experiments were an unqualified success.

Nineteen sperm whales were tagged. All tags were recovered yielding over 77 hours and 14

Gbytes of digital data. Several notable events occurred including a 15-hrs tag deployment that is

the longest to date, a synchronized dive by a pair of tagged whales, and three whales tagged at

the same time. Foreign whale codas were played to tagged animals but, although two attempts

were made, uncertainty in the position of the tagged whales precluded the opportunity to

playback familiar codas. Most importantly, two controlled exposure experiments of whales to an

operating seismic vessel were achieved, including one with three simultaneously tagged whales.

Seventeen fluke photographs were taken of 13 animals for photo-identification and three framesets (measured length of animals) were made. Fourteen sperm whale skin samples were

collected, thirteen from D-tag suction cups and one from biopsy sampling equipment. The visual

team enjoyed 13 days of good visual working conditions and the acoustics team recorded data on

20 of 25 days from two hydrophone arrays aboard the Gyre, as well as numerous days from the

array aboard the Rylan T./Speculator.
30

Table 3.2.1

The SWSS 2002 cruise, Leg 2, D-tag science team

Description Person (Institutional affiliation)

R/V Gyre 02G11 Science Team Captain Dana O. Dyer III, Gyre captain

Field Party Chiefs Mark Johnson (WHOI) for basic D-tagging

Peter Tyack (WHOI) for CEEs

Electronics Technicians Eddie Webb (TAMU College Station)

Paul Clark (TAMU GERG)

Deck Engineers Billy Green (TAMU Galveston)

Mike Fredericks (TAMU GERG)

Tagging Team Mark Johnson (WHOI)

Patrick Miller (WHOI)

Alessandro Bocconcelli (UNCW)

Visual Team Nicoletta Biassoni (WHOI)

Maria Elena Quero (WHOI)

Dan Engelhaupt (Durham Univ. UK)

Todd Pusser (North Carolina)

Amy Beier (New Zealand)

Irene Briga (Massachusetts)

Mandana Mirhaj (Germany)

Simon Childerhouse (DoC, New Zealand)

Dee Allen (NMNH Smithsonian)

Acoustics Team Aaron Thode (SIO)

Valeria Teloni (WHOI, Italy)

Matt Grund (WHOI)

Natacha Aguilar de Soto (Spain)

Sarah Tsoflias (MMS New Orleans)

Physical Oceanography Matthew Howard (TAMU College Station)

Flow through Fluorescence/CHL Laurie Sindlinger (TAMU College Station)

M/V Rylan T. Science Team Captain Steve Bennett, Rylan T captain

Seismic Team Cliff Smith (Fairfield Industries)

Tony Edwards (Fairfield Industries)

Neil Estay (Fairfield Industries)

Acoustic Team Tim Pinnington (Seamap Inc.)

Craig Douglas (Seamap Inc.)

Playback/Permit Team Natacha Aguilar de Soto (transfer from

Gyre)

Bill Lang (MMS New Orleans)

Carol Roden (MMS New Orleans)

Sandy Sawyer (Fairfield Industries)

UNCW is University of North Carolina at Wilmington

DoC is the Department of Conservation, Wellington, New Zealand

NMNH is National Museum of Natural History

GERG is the Geochemical and Environmental Research Group at TAMU
31

Thirty-eight XBT probes were dropped, eight CTD casts were taken, and chlorophyll

concentrations were measured from 75 water samples. Continuous vertical profiles of horizontal

currents were collected whenever whales were not present, and continuous near-surface

measurements of temperature, salinity, and fluorescence were recorded whenever the vessel was

underway.

The study was conducted between the 700-m and 1500-m isobaths, mainly on or near the 1000-

m isobath, between 93°W and 88°W in the northern Gulf of Mexico. This region includes the

continental slope south of the Mississippi River delta between the Mississippi and DeSoto

Canyons. This area was where historical sightings and recent reports from satellite-tagged (Stag) whales indicated there was a high-probability of encountering pods of sperm whales.

Figure 3.2.1 shows the ship track for three periods. The first panel shows the transit from

Galveston to Mississippi Canyon where sperm whales were first encountered and where four

were tagged (sw235a, b, c, and sw236a; see Table 3.2.2). On 25 August the ship moved

northwest to 28.6°N and 89°W, a location that was revisited several times later in the cruise.

Nine whales (sw237a-sw240c) were tagged in the vicinity over a 5-day period. On August 29,

the ship transited to DeSoto Canyon, but found few whales there. Due to a family emergency, the

deck engineer was put ashore in Gulfport, MS, on 30 August.

The second panel of Figure 3.2.1 covers the middle period of the cruise from 30 August to 8

September. During this time the Gyre rendezvoused with the Rylan T. (31 August) and worked

whales between the Main Pass and DeSoto Canyon. Weather and sea-state hampered operations

(see under "Tagging" below for additional information). On 5 September, after tagging one

whale (sw248a) a group of whales was followed south overnight into the western edge of a coldcore eddy. There one whale (sw249a) was tagged before Gyre and Rylan T. were chased by bad

weather to an area west of the Mississippi. The ships remained anchored there for two and a half

days to avoid the remnants of Tropical Storm Edouard to the east and the growing Tropical

Storm Fay to the west.

The third panel of Figure 3.2.1 shows the track for the third period covering 9-15 September.

During this period, Gyre returned to the region near 28.6°N and 89°W with the Rylan

T./Speculator. Several successes were achieved in this region, including the controlled exposure

of one (sw253a) and three tagged whales (sw254a,b,c) to the airgun sounds. These controlled

exposures were made possible by a two-day extension of the Rylan T. contract by the IAGC.

After the departure of the Rylan T. on 11 September, Gyre steamed westward looking for

smoother water. On 14 September the tag team approached a large male, but was not able to get

close enough for tagging operations. The biopsy/photography team then went out for a few

hours. After they finished, the ship headed for Galveston, TX, arriving at 8:30pm local time on

15 September.

All D-tag and biopsy/genetic typing activities were conducted in accordance with federal permits

from the US National Marine Fisheries Service to Peter Tyack/Woods Hole Oceanographic

Institution (permits 981-1578-01 and 981-1578-02) and to Dan Engelhaupt/University of

Durham (permit 909-1465-01).

General Operations

Operations generally were conducted in accordance with the D-tag cruise plan of 9 August 2002.

Upon reaching the study area, a combination of visual and acoustic searches were made to locate

whale pods and to follow individuals. The visual search comprised two watches on two-hour

rotations using high-power (x25), large-format "BigEye" binoculars. The acoustic search effort

comprised two watches, each using one or two hydrophone arrays in conjunction with custom
32

-93 -92 -91 -90 -89 -88 -87 

28 

29 

30 

200m, 1000m, and 2000m isobaths shown

-93 -92 -91 -90 -89 -88 -87 

27 

28 

29 

30 

200m, 1000m, and 2000m isobath shown

-93 -92 -91 -90 -89 -88 -87 

27 

28 

29 

30 

200m, 1000m, and 2000m isobath shown

21-30 August 2002

30-August to 08-September 2002

08-15 September 2002

Figure 3.2.1. D-tag cruise track for R/V Gyre (02G11) on 21 August to 15 September 2002.
33

Table 3.2.2

List of 19 D-tag placements on sperm whales

(Shown are date, reference number (Julian day plus letter), the D-tag used (D-tag identification

number), the number of complete deep dives made by the animal while tagged, and the number

of hours of digital data recorded by the D-tag while on the animal. The total number of hours for

all tags is 77.12 hrs.)

Date

Tagging

Event

Reference

Number

D-tag

Identification

Number

Number of

complete deep

dives

On-animal

data-hours

23 August 2002 235a 10 0 0.18

23 August 2002 235b 12 0 0.46

23 August 2002 235c 10 1 1.32

24 August 2002 236a 10 0 0.49

25 August 2002 237a 10 2 3.51

25 August 2002 237b 12 0 0.56

26 August 2002 238a 10 3 4.44

26 August 2002 238b 12 3 2.11

27 August 2002 239a 10 12 12.36

27 August 2002 239b 12 1 0.89

29 August 2002 240a 12 1 0.73

29 August 2002 240b 12 0 0.37

29 August 2002 240c 10 5 5.22

5 September 2002 248a 10 1 0.89

6 September 2002 249a 12 2 1.92

10 September 2002 253a 12 3 5.41

11 September 2002 254a 10 11 11.54

11 September 2002 254b 12 10 12.36

11 September 2002 254c 11 10 12.36

software to determine relative bearing to individual whales. When whales were located, the

visual and acoustics team worked together to track the group and collect pre-exposure

observations. During daylight hours, the range and relative bearing to each whale was collected

visually using Big-eye binoculars and these data were entered into custom software to resolve

and record the whale's locations in geographic coordinates. The acoustics team recorded bearings

to whales and the start-times and end-times of dives (as determined by the regular clicking of

sperm whales). Digital tape recorders captured continuous records of the sound fields detected by

the hydrophone arrays. The acoustics search and tracking effort operated day and night. Similar

acoustic operations were conducted onboard the Rylan T. The success of the search effort is

demonstrated by the fact that whales were located and tracked on 12 out of 13 fair weather days.

Additional information on sperm whale locations was available through daily reports provided

by Tomas Follett of Oregon State University on S-tagged whales. During the D-tag leg, several

of the S-tagged whales were sighted.

During daylight hours, when whales were present and the sea-state acceptable, an attempt was

made to place a digital-recording tag (D-tag) on the animals using a 46-ft carbon fiber spar
34

mounted on one of two small boats. The tag contains a 3-axis accelerometer, pressure sensor,

compass, hydrophone, VHF beacon, 2.2Gb of solid-state memory and a pair of active suction

cups. Playback of recorded whale codas was done by playing a CD through a projector

suspended beneath the tagging boat. Airgun sounds were provided by the seismic vessel

Speculator, mounted on the back deck of the Rylan T. These sounds also are called "seismic

playbacks", even though they are made directly by the seismic vessel's actual airguns. The

Speculator hosts a 1680 cubic-inch airgun system, which produces an acoustic signature nearly

identical to that of a deepwater 3D airgun array at the distances required to be maintained from

the whales on this cruise.

Habitat characterization was achieved by measuring temperature, salinity, fluorescence,

chlorophyll, and currents on a not-to-interfere-with-tagging basis. The flow-through systems

were run continuously and XBTs were dropped at will. The ADCPs were operated primarily

during long straight runs to new locations. CTD casts were taken when the acoustic arrays were

onboard and time permitted the ship to stop for sampling.

Biopsy/genetics sampling was dependant on obtaining skin samples. Most of the tags had

fragments of skin stuck in the suction cups. One biopsy sample was taken by Dan Engelhaupt, on

the last day of operations, using the dart method of sampling.

Both the Gyre and the Rylan T. passed over EARS acoustic buoys deployed by the Navy near

28.5°N 89.0°W. This will provide some quantification of sound emissions from the two vessels.

Fairfield 1680 in3 Airgun Array

The IAGC provided a representative airgun source for use in the controlled exposure

experiments conducted by the WHOI research group on D-tag. This airgun array consisted of 20

external sleeve type airguns arranged on two separate gun strings (10 guns per string). The array

volume totaled 1680 in3 and had areal dimensions of 8m long by 7m wide. It produced a nearly

identical acoustic signature as that of a deepwater 3-D airgun array at the distances required to be

maintained from the whales on this cruise. Airguns were towed at a depth of 6m. A schematic of

the system is shown in Figure 3.2.2.

The array and required air compressors, air-lines, control electronics, and electrical connections

were rigged out on Fairfield Industry's shallow water vessel Speculator. In order for the array to

be used in the deep water research area, Fairfield arranged for the Speculator to be piggybacked

on the deep water service vessel Rylan T. The array produced a vertical far-field signature with a

theoretical point source response of around 252 dB re 1μPa in the 3 to 800 Hz frequency band, as

shown in Figures 3.2.3 and 3.2.4.

Because of the areal dimensions of the array, the pressure signal varied as a function of azimuth

and emission angle (i.e., angle from the vertical). In order to predict maximum acoustic pressure

levels at various distances from tagged whales a set of signatures were modeled for emission

angles for various distances corresponding to a tagged whale at a depth of 1,000 m. Table 3.2.3

was then complied to guide the researchers in controlling the source exposure within the limits of

the scientific permit allowing these tests.

Visual Survey and Monitoring

During the day, the visual team controlled the direction of the Gyre. Two teams of four visual

observers kept watch from the flying bridge from dawn to dusk. Their job was to locate sperm

whales, keep track of the location and time of "blows" (breathing at the surface) and "fluke-ups"

(a behavior indicative of the initiation of a deep dive), to guide the tagging team into proximity

of targeted animals, and to keep track of the D-tags after they were deployed. This last item is the

notable distinction between operations during the S-tag cruise and the D-tag cruise.
35

Figure 3.2.2. Schematic of airgun array of Fairfield Speculator.

Figure 3.2.3. Far-field signature of airgun array.
36

Figure 3.2.4. Amplitude spectrum of far-field signature of airgun array.

Table 3.2.3

Emission angles from the V1680 array for various distances corresponding to a tagged whale at a

depth of 1,000 m

(Shaded cells are greater than 180 dB.)

Emission Range (km)

Angle (°) 500 1000 2000 3000 4000 5000 6000

45 192.6289 186.6083 180.5877 177.0659 174.5671 172.6289 171.0453

63 191.0777 185.0571 179.0365 175.5146 173.0159 171.0777 169.4940

72 188.3660 182.3454 176.3248 172.8030 170.3042 168.3660 166.7824

76 188.1648 182.1442 176.1236 172.6018 170.103 168.1648 166.5812

79 187.8187 181.7981 175.7775 172.2557 169.7569 167.8187 166.2351

82 187.6042 181.5836 175.5630 172.0412 169.5424 167.6042 166.0206
37

Once an animal was tagged with an S-tag, it received no further special attention by the visual

team. On the D-tag cruise, however, when one or more whales were tagged, both visual teams

went on watch. One team continued normal operations while the other team focused on

following the tag. Although sightings of other marine mammals were noted and logged, the

emphasis of the work was on sperm whales.

Three sets of BigEye binoculars were available to measure distance and relative bearing from the

ship to animals. Distance was computed via geometry using the known altitude of the binoculars

in conjunction with reticule markings in the eye-pieces. From the flying bridge of the Gyre, the

horizon was approximately 12km away which yields a searchable area of approximately 450

km2. As each animal was sighted, the observer relayed the reticule and relative bearing

information to the data entry person. These data were entered into the "Logger 2000" data

collection software along with information such as animal behavior (blow, fluke-up) and heading

("Logger 2000" was developed by the International Fund for Animal Welfare to promote benign

and non-invasive research). A custom navigational data string, updated every second, containing

ship's heading and location to the Logger software was provided by the TAMU electronics

technician, Eddie Webb. This information, when combined with the relative bearing and distance

from the binoculars, produced a latitude and longitude fix for each animal. The information is

stored in a Microsoft Access database. In practice, about 12 animals at a time can be followed

visually using this system. Figure 3.2.5 shows the locations of sperm whale sightings by date.

After one or more animals were tagged, the second watch went up to the flying bridge to follow

the tag. They do this visually and by means of radio beacon tracking equipment designed to

receive the VHF signal from the tag. The beacon can only be heard when the tag antenna is out

of the water. The tagging team tries to place the tag high on the animal near the dorsal fin

because this area of the animal is frequently out of the water when the animal is at the surface.

The tag is designed to float with the antenna in the air when it is not attached to an animal. Thus,

an intermittent signal usually indicates the tag is still on the animal while a continuous signal

usually indicates the tag is off the animal and is floating at the surface. Often, the tag will remain

on after dark, sometimes almost to dawn. The task of monitoring the radio equipment after dark

was primarily borne by the visual team. The beacon frequency is different for each tag. When

two or more tags were deployed, two or more VHF units and monitors were needed. At one

point, three tagged animals were being worked. This would appear to be the practical limit both

for the visual observers and the VHF monitors given the equipment and personnel available.

Tagging

A typical sperm whale dive cycle begins with a 10-15 minute period at the surface followed by a

40-50 minute dive. During the dive the animal may move laterally some 500 to 1000m.

Therefore, the tagging team, which normally operates within the large visual survey region,

needs timely information to intercept whales at the surface. Often they will arrive in the vicinity

just as the whale dives. The tag team then stays in the general area using acoustic tracking

equipment on the tag boat so as to be close to the whale at the next surfacing. Some whales were

skittish and difficult to approach. At such times the whales either speed up or execute a series of

shallow dives changing direction as they do. Other whales were unperturbed by the boat's

approach. The triple tagging was accomplished on such a group.

The tag team consisted of scientists Mark Johnson and Patrick Miller, and boat operator

Alessandro Bocconcelli. On days when tagging was possible they usually departed between 8

and 9am, returned once between noon and 3pm for a few hours to service a recovered tag, and

went out again returning for the day around dusk (~7:15pm). After return, the team scientists

worked to recover and download tags. Three D-tags were available for use, but once used, each

required several hours to download and refurbish.
38

Figure 3.2.5. Locations of visual sightings of sperm whales during the 2002 D-tag cruise.

Nineteen whales were tagged during the D-tag experiment as shown in Table 3.2.2. Fourteen

animals completed at least one dive before the tag came off. A total of 65 deep dives were

recorded. Figure 3.2.6 shows a map of the locations where whales were tagged. Figure 3.2.7

shows a 2-D representation of the 3-D trajectory of two tagged whales that dove together. The

record shows the animals dove to 500-m depth and traveled horizontally some 1500 m before

surfacing.

A key goal of this cruise was to conduct controlled exposure experiments (CEEs) using a seismic

source. The seismic source vessel, the Rylan T. with the Speculator on deck, rendezvoused with

Gyre on 31 August. Whales were in the area, but so was at least one other seismic vessel and

efforts were made to move away from that vessel. Weather also became a significant problem as

two tropical cyclones, Edouard and Fay, impacted the survey area. During the time the Rylan T.

was at sea, weather conditions were generally poor to bad, making tagging operations difficult.
39

27°N

28°N

29°N

30°N

New Orleans

91°W 90°W 89°W 88°W 87°W 86°W

Figure 3.2.6. Locations where sperm whales were tagged with digital tags (D-tags) during

SWSS cruise Leg 2, August/September 2002. Bathymetry contours are 200, 1000,

2000, and 3000 m.

Personnel were not transferred between the Rylan T. and Gyre until the evening of 2 September.

Natacha Aguilar de Soto was transferred to the Rylan T. and Peter Tyack and Sarah Tsoflias

were transferred to Gyre. Much of 3 September was spent trying to locate whales acoustically,

with the visibility too poor for successful visual operations. The tagging efforts on 4 September

were curtailed due to rising seas, after two unsuccessful tagging approaches to whales by the tag

boat. On 5 September, no whales were found until late afternoon. One whale was tagged

(sw248a), but the tag did not stay on long enough to conduct experiments. A whale was

successfully tagged on 6 September (sw249a), but the tag came off just as the Rylan T. began to

prepare for a seismic test. No additional whales were tagged that day because none could be

approached closely enough to tag. Tropical Storm Fay prevented all activities for two days, as

both vessels anchored in shelter. On 9 September, the Gyre and Rylan T. returned to the survey

area and located whales acoustically in the afternoon. September 10 provided the first successful

controlled exposure experiment using the seismic source; the tagging (sw253a) was done in sea

state conditions that were becoming marginal for small boat operations and with rain and squalls

in the area. September 11th provided another successful experiment, with three whales tagged

(254a-c) for a period extending well beyond the seismic source testing. After the seismic source

test on the 11th, the Rylan T. headed into port. On Figure 3.2.8 are shown the relative positions

of the Gyre (coinciding with the black cruise track) and the Rylan T during the ramp up of the

airguns and the seismic test. The locations and airgun transmission levels for 10 September are in

browns and for 11 September are in blues; the scale is shown on the right, with 1680 in3 being

maximum. Table 3.2.4 shows the ramp-up/mitigation timeline for the two controlled exposure

experiments using the airguns. During these experiments, there was visual and acoustic

monitoring on the Rylan T. to ensure no sea turtles or sperm whales were in the immediate area

of the vessel during ramp-up and firing operations per permit requirements. The experience
40

between 31 August and 11 September indicates that future cruises should be conducted earlier in

the hurricane season to increase the likelihood that the weather conditions will be more amenable

to tagging efforts.

Two tag boats were available to use during tagging activities. The MMS tag boat (R2) was

intended to be the primary vehicle. During pre-tagging activities (radio range checks and

calibration of the acoustic arrays) the check engine light came on first on one and then both of

the Mercury 135hp Optimax gasoline engines. The boat was brought on board and an extensively

evaluated to diagnose the reason for warning lights. Despite efforts, nothing was resolved, so a

decision was made to use the OSU diesel-powered tag boat, Puffin. The OSU boat was used until

the end of August at which time the starter motor on it failed. Although the cause of the engine

light on the MMS boat had not been resolved, the engines started easily and ran acceptably,

albeit noisily at high rpm. With MMS concurrence, the MMS boat was put in service and all

further tagging operations were conducted from this boat. The OSU boat was deployed from the

port side of the Gyre using the ship's crane while the R2 was deployed from a custom launch

ramp over the fantail. Both deployment/recovery methods were usable in all sea conditions

appropriate for tagging.

Figure 3.2.7. Dive profiles from two D-tags for sperm whales diving together.
41

Figure 3.2.8. R/V Gyre track (black) and Rylan T./Speculator track (color) during controlledexposure experiments on 10 and 11 September 2002. Color represents the air

volume and is proportional to the sound level intensity. Color is repeated on the

Gyre track to show its position at the same time as the airgun array was operating.

Selected isobaths are shown in green and pink.

Acoustics Monitoring

Two watches staffed the acoustics lab aboard the Gyre rotating day and night. At night when

whales were present, the acoustics team dictated the course of the Gyre. Two acoustic arrays

were available, each with different acoustic characteristics. The first was the Ecologic acoustic

array. The second was the WHOI array, which had a "towfish" sometimes called a "batfish"

depressor that pulled the end of the array into a somewhat vertical orientation with the bottom at

a depth of 140m or so. In principle, the Ecologic array could be towed faster as it had no

depressor and was allowed to stream out a 400-m tow cable horizontally behind the vessel. Both

hydrophone arrays were used during the experiment and both fed their signals into the software

package called "Rainbow Click," written by Douglas Gillespie of the International Fund for

Animal Welfare (to promote benign and non-invasive research), and "Ishmael," written by David

Mellinger of Oregon State University. These programs have many features, but primarily

allowed the acoustic team to determine the relative bearing to many whales at once. There is a

left-right ambiguity in the relative bearing which is resolved by turning the ship to different

bearings and following the change in relative bearing. Figure 3.2.9 shows the portion of cruise
42

Table 3.2.4

Timeline for ramp-up of airguns on Speculator for D-tag controlled exposure experiments on 10

and 11 September 2002

(Mitigation observations are noted.)

Time Latitude (°N) Longitude (°W) Comments

9/10/2002

16:40 28° 27.5 88° 58.46 Tag on

17:10 28° 25.55 89° 00.36 gun deployment started

17:20 28° 25.25 89° 00.89

17:25 28° 24.92 89° 01.54 guns in water

17:35 28° 24.29 89° 01.28

17:40 28° 24.08 89° 01.09

17:50 28° 25.52 89° 00.09

17:55 28° 23.18 89° 00.38 first shot attempt – boot failure

17:59 28° 22.98 89° 00.26 first shot large grain ship at 4.8 nm

18:04 80ci

18:13 grain ship at 3.4 nm

18:14 340 ci

18:18 turn to cut past grain ship stern

18:19 28° 22.63 89° 01.30 640ci

18:29 28° 21.94 89° 00.92 1680 ci full array power

18:34 28° 21.58 89° 00.69 Gyre radios 145db level

18:54 28° 20.31 89° 59.68 course change to close slightly

19:15–19:19 dolphin shut-down

19:29 28° 19.22 88° 57.17 END

9/11/2002

10:14 28° 42.80 88° 56.3 TAG ON 28° 39.89 88° 59.2 3.4 nm away

10:28 28° 42.06 88° 57.5 TAG 2 ON

10:33 28° 39.81 88° 59.92 TAG 3 ON

10:57 Gyre estimates about 20 whales around them

11:10 28° 42.54 89° 00.77 observers to flying bridge

11:19 28° 42.89 89° 01.71 Gyre due west at 4.4 nm

11:33 gun deployment begun

11:40 28° 43.11 89° 03.90 guns out

12:10 28° 41.57 89° 05.28 Gyre at 4.5nm platform at 4.0 nm

12:16 28° 44.14 89° 05.58 ramp-up begun

12:26 28° 40.47 89° 05.82 160 ci 4.3 nm to Gyre

12:31 28° 40.08 89° 05.86 320 ci

12:35 28° 39.69 89° 05.86 640 ci

12:41 28° 39.30 89° 05.83 1280 ci platform at 3.25 nm

12:46 28° 38.92 89° 05.79 full power at 4nm to Gyre

12:48 28° 38.72 89° 05.78 approach starts to 2.5 nm

12:51 3.8 nm

12:56 3.6 nm

13:12 28° 36.81 89° 05.61 3.25 nm

13:20 28° 36.17 89° 05.67 3.1 nm

13:22 Tuna off bow

13:26 Bottlenose 2-6 off bow SHUTDOWN

13:43 28° 34.27 89° 05.96 half-ci start-up

13:50 28° 33.74 89° 06.17 full power on guns

13:51 Tuna off bow

13:53 28° 33.44 89° 06.37 order to close mile

13:56 more tuna

14:01 28° 33.05 89° 06.57 2.25nm

14:13 28° 32.21 89° 06.73 2.0nm

14:20 28° 31.73 89° 06.78 END
43

Figure 3.2.9. Ship track color-coded according to which hydrophone array was in use.

track where each array was used. The number of acoustic contacts by geographic location are

indicated by Figure 3.2.10.

During the S-tag cruise, the Ecologic array persistently detected noise at a frequency of 19kHz.

This noise was observed early on during the D-tag cruise. It was ruled out that this might be due

to sub-harmonics of the 38kHz ADCP system because the noise was at 18.45kHz and was a

continuous signal, whereas the ADCP has a pulse signal that makes a distinctive discrete signal

resembling a vertical array of short horizontal lines when displayed in Rainbow Click. Aaron

Thode worked with the ship's engineer to try to locate a shipboard electrical source for the noise

but none was found. On the S-tag cruise, the problem had been eliminated by using a different

top-end amplifier/conditioner unit. This "quiet" amplifier then was used on the D-tag cruise.

However, when the same noise was present on the D-tag cruise, it was eventually cured by

replacing one of the hydrophones and preamplifiers in the streamer suggesting that a faulty

hydrophone preamplifier was the cause. A further problem developed when the cable was

damaged, apparently through being towed with a kink in it. Initially this limited the tow speed to

3 knots but eventually the cable failed completely. The WHOI array proved more reliable but

restricted the vessel speed to 4.5 knots. This was useful for monitoring whales already known to

be in the area but was too slow to search for whales over large areas.
44

Figure 3.2.10. Numbers of acoustic contacts during the 2002 D-tag cruise.

Twice, during the cruise ranging, experiments were performed to estimate the detection range of

the arrays. On 29 August, during a time when no sperm whales were present, a small workboat

was deployed from the Gyre and driven to points 1.5 and 2.6 nautical miles from the ship. At

these two points light bulbs were imploded underwater to generate an impulsive sound roughly

like a sperm whale click. The implosions were clearly heard at 1.5 nm on the WHOI array, but

barely heard, if at all, at 2.6 nm, suggesting an effective detection range of 4 km, much lower

than the 10 nm range or higher reported in the Pacific (Barlow and Taylor 1998).

An additional detection test was performed on a sperm whale group using the Ecologic array on

3 September, when the seismic source vessel Rylan T. was present. While the Rylan T. remained

in the vicinity of the group, the Gyre drove directly away from the group until sperm whale

sounds could no longer be heard, then turned around and determined when the click sounds

became audible again. At a speed of 3.3 knots the Ecologic array had a detection range of about

3.5 km, very close to the WHOI array performance.

One reason behind the limited detection range was ship noise. When the Gyre was commissioned

in 1973 it was not designed to be acoustically silent. The WHOI array, in particular, suffered

from ship noise contamination because the towfish pulled the array not only deeper, but into a

noisier region below the ship. It was found that whenever the ship traveled slower than around 2
45

knots, one of the engines would have to be disengaged, creating a large amount of noise. Even at

higher speeds the WHOI array was effectively awash in prop noise.

However, previous acoustic D-tag work in the Gulf on a different ship with different arrays has

produced similar detection range results, suggesting that propagation conditions in the Gulf are

fundamentally poor for long-range acoustic propagation. XBT and CTD data collected during the

cruise show that the effective vertical sound-speed profile in the study region showed a very

strong decrease in sound speed with depth, a feature that would be expected to refract acoustic

energy into the ocean bottom, away from the surface. Figure 3.2.11 shows an example of an

average sound speed profile (thin line), as well as the largest perturbation from the mean profile

observed, created after a week of rough weather and storms had mixed the upper 50 m of the

ocean (thick line).

The agreement of a numerical simulation with the empirically-measured detection range results

suggests that poor propagation conditions are a fundamental fact of life in the Gulf, and

simplified acoustic propagation assumptions like cylindrical spreading are inappropriate for the

region. Figure 3.2.12 shows the numerical propagation with energy reaching the surface between

3 and 6 km. If a towed array system is well-designed and deployed from a quiet vessel, then the

detection range might be extended to about 6 km, a threefold increase in search area. The way to

improve detection range further is not by increasing array depth, but by increasing the array gain

by incorporating additional hydrophones into an array system. For example, the R/V Alliance, a

quiet ship using a 128-element hydrophone array, is able to achieve detection ranges in excess of

20 nm in summer-stratified conditions in the Mediterranean Sea.

0

-200

-400

-600

1480 1490 1500 1510 1520 1530 1540 1550

Sound Speed (m/s)

Depth (m)

Average Sound Speeds Before and After Storm Mixing

Figure 3.2.11. Average sound speed profile (thin line) and perturbation after a week of rough

weather and storms had mixed the upper 50 m (thick line).
46

Acoustic Monitoring on the Rylan T.

Natacha Aguilar de Soto was in charge of permit compliance monitoring for the seismic vessel

and worked aboard the Rylan T whenever there was a chance that whales would be approached

by the Rylan T when the Speculator's airguns were operating.

The passive acoustic system onboard the Rylan T. was provided by Seamap Inc. It was operated

by Craig Douglas and Tim Pinnington from Seamap, and used by Natacha Aguilar de Soto in her

role as permit monitor onboard the Rylan T. Because of limited detection ranges on board the

Gyre, the Seamap role expanded from permit monitoring duties to frequent 24-hr acoustic

watches to aid in detection and tracking of whales. During the cruise, acoustic team members on

the Gyre worked extensively with the Seamap team and had the opportunity to view the array,

recording hardware, and software. The Seamap array and personnel provided considerable help

to the acoustics effort, and the combined search and tracking efforts from both vessels improved

detection abilities.

The Seamap system consisted of an oil filled passive acoustic listening array, 56 m long, which

was connected to the vessel via a 300-m tow cable. The array was deployed astern of the Rylan

T. such that the head of the array was 250 m from the stern. The array was ballasted to maintain

40-m depth when towed at 5 knots. At this tow speed, the array was able to detect sperm whale

vocalizations out to a range of 5-6 km. During transit between areas, the Rylan T. steamed at

speeds between 7 and 8 knots. At this higher speed the array maintained depths between 8 and 10

m. During the higher speed steaming, the array was fully functional, but the effective range was

reduced from 5-6 km to 3-4 km. Still higher towing speeds could have been supported with the

use of supplemental ballasting, which was available on the vessel in the form of hinged weight

collars.

The towed array comprised two channels configurable from a selection of any combination of 4

hydrophones. The distance between the outer phones was 50 m with the two center phones

between these placed at frequency thirds. The onboard system was configured to two of these

groups with a hydrophone spacing of 5.55 m. This separation was chosen as optimal for sperm

whale detection.

The system offered a suite of visualization and detection facilities that monitored audio

frequencies in real time from 8Hz to 22000Hz and also recorded acoustic data in a proprietary

format that subsequently was exported in "wav" file format. The system also was interfaced to

GPS to provide positional information that allowed detections to be plotted on the system's

mapping software.

During the trial, a TASCAM recorder was attached to the analogue output from the system to

provide continuous recording of acoustic data during critical periods. In addition to this

recording, the Seamap Cetacean Monitoring System also recorded more than 6 hours of animal

vocalizations. The system automatically buffered the last two minutes of digital audio data in the

internal memory for recording to hard drive at any time by a single operator mouse click.

The system was deployed on 31 August and was in nearly continuous use until 7 September

when it was recovered onboard when the Rylan T. and Gyre went to anchor west of the

Mississippi Delta sheltering from the weather. The streamer was deployed again on 9 September

and remained in use until 11 September when the Rylan T. left to demobilize in Texas City. The

system performed without any equipment downtime for the entire period of the trial.
47

Source depth 800m, Frequency 1000Hz, bottom type: sand

Figure 3.2.12. Acoustic transmission loss, in dB, from a source at 800-m depth in 1000-m deep

water over a sandy bottom. The figure was made using a normal mode model,

KRAKEN, which is accurate out past a 1-km range.

The Seamap array was able to track sperm whales within 6 km of the operation. For a short

interval before the Rylan T. became engaged in CEE support, range and bearing estimates for

sperm whales that were about to surface were provided by the Seamap team and confirmed by

visual observers on board the Rylan T. with surprising consistency. This exercise was for

tracking and testing equipment for a monitoring role.

Tagging and Playback Coordinators

Coordination of the tagging and seismic playback activities was achieved by Dan Engelhaupt

and Peter Tyack, respectively. Their task was to maintain situational awareness of the various

operations going on with the tag boat and the seismic vessel, merge the information coming from

the acoustic and visual team, and communicate with the ship's bridge crew. This can be quite

challenging when all players are active. It would appear that 3 tagged whales and 3 vessels are

currently the practical limit for such control.

Tissue Collection/Genetic Typing

Figure 3.2.13 shows the locations at which tissue samples were collected. Tissue sampling

during the D-tag cruise was primarily focused on the opportunistic collection of sloughed skin

often found attached to the D-tag suction cups placed on sperm whales (Table 3.2.5). Sloughed

skin samples from eleven D-tagged sperm whales were collected during the four-week cruise.
48

27°N

28°N

29°N

30°N

New Orleans

91°W 90°W 89°W 88°W 87°W 86°W

Figure 3.2.13. Locations where skin or biopsy samples were collected during SWSS cruise Leg

2, D-tag, August/September 2002. Bathymetry contours are 200, 1000, 2000, and

3000 m.

Two samples of sloughed skin found free-floating in the water near a group of whales were

collected with a dipnet. While sloughed skin obtained from D-tags has proven fairly reliable in

the past, sloughed skin in general can be quite difficult to amplify given the DNA's somewhat

degraded nature. Due to the extensive weather delays, biopsy sampling was limited to one day

with what was thought to be a large sub-adult, or perhaps adult, male based on size estimates

from the R2 tag boat. Although this whale proved extremely skittish and evasive to the RHIB, a

very minute amount of skin was collected from a biopsy dart that skimmed the whale's back. If

this sample provides adequate DNA for analysis, this will mark the largest whale sampled to date

throughout the northern Gulf of Mexico and the first free-ranging sperm whale sampled in the

western region of the northern Gulf of Mexico. Based on previous and ongoing surveys, large

sexually and physically mature males are not common in the northern Gulf of Mexico. Future

cruise decisions to biopsy sample, photo-ID, and incorporate photogrammetry techniques on all

'larger' sperm whales will surely aid the overall goals of this research.

The combination of D-tagging and genetic sampling continues to provide an in-depth

examination of sperm whales found throughout the northern Gulf of Mexico. Molecular sexing,

microsatellites, and mitochondrial DNA sequencing will provide a rich set of information that

can be directly integrated with the dive profiles of D-tagged whales. For example, we obtained

skin samples from multiple members of three groups (Group #s 1, 3, and 7; see Table 3.2.5). An

extremely exciting and interesting result was the collection of skin from all three members

(Group 7) of the 'triple-dog' tagging session. Preliminary visual results suggest that the tagged

members of Group 7 were surfacing in close proximity to each other. Degrees of relatedness will

be tested between whales found within all sampled groups. The combination of genetics and
49

WHOI D-tag dive profile data may perhaps shed light on how related and unrelated whales

found within groups in the northern Gulf of Mexico coordinate both deep foraging and shallow

dives.

In an ideal situation, one would attempt to sample all members that comprise a group. Given this

year's primary focus on the D-tagging effort and the inclement weather, this was simply not

possible. While our resulting genetic composition of groups will not portray an accurate

representation of group structure for free-ranging sperm whales found in the Gulf of Mexico, the

benefits of combining skin sampling and D-tagging will surely provide numerous answers to

previously unknown questions.

Table 3.2.5

Tissue collection and genetic typing samples collected during SWSS 2002 D-tag fieldwork

(The sample number code gives the date (yymmdd) followed by the consecutive number for

multiple samples taken on any given day (01 to 04).)

Sample

No.

Tag

No.

Group

No.

Approx. Number of

Whales in Area

Longitude

(°N)

Latitude

(°W)

02082301 1 20 -89.5618 28.2387

02082302 1 20 -89.5189 28.3014

02082303 SW235B 1 20 -89.6640 28.3303

02082304 SW235C 1 20 -89.5189 28.3014

02082401 SW236A 2 7 -89.4053 28.2208

02082501 SW237A 3 15 -88.6930 28.7800

02082502 SW237B 3 15 -88.7102 28.7907

02082601 SW238A 4 5-10 -88.9445 28.6863

02082801 SW239A 5 10 -89.0052 28.6511

02082901 SW240B 6 10 -88.5995 28.8319

02091101 SW254A 7 15-20 -88.9829 28.6645

02091102 SW254B 7 15-20 -88.9924 28.6617

02091103 SW254C 7 15-20 -88.9953 28.6612

02091401 8 2 -92.7571 27.6503

Environmental Characterization

Several types of measurements were collected to characterize the physical-biochemical

environment during the cruise. Conductivity-Temperature-Depth (CTD) profiles provided the

most complete information about temperature, salinity, density, and sound speed structure of the

water column. However, CTD casts were only made when the ship was stopped. When

hydrophone arrays were deployed, the ship cannot stop or the arrays will sink. Due to these

mutually exclusive requirements, only 8 CTD casts were taken (Figure 3.2.14a). Table 3.2.6

shows the date, time, location, and depth of cast for each CTD cast.

Expendable temperature profiles (XBTs) which can be deployed from a moving ship, are the

next best alternative for determining sound speed profiles. Thirty-eight XBTs were deployed,

with 35 giving profiles to approximately 760 m. Because we were following whales, it was never
50

Figure 3.2.14. Locations of hydrographic stations on SWSS Leg 2, D-tag, in August/September

2002. Shown are (upper) the locations of the 8 CTD casts and (lower) 35 of the 39

XBT probes deployed.

clear where we would be from hour to hour or day to day. This made it somewhat difficult to

plan the deployment of the XBTs to get good spatial coverage, but the coverage turned out well

(Figure 3.2.14b). Table 3.2.7 shows for each XBT drop the time, location, and depth of the 15°C

isotherm.

-93 -92 -91 -90 -89 -88 -87 

28 

29 

02

03

04

05

06

07

08

10 11

13 14

15

16

17

18 20 21

22

23

24

25

26

28

29

30 31

32

33

34

35

36

37 38 39

200m, 1000m, and 2000m isobaths shown

12

XBT Probe Deployment Locations during D-Tag Cruise R/V Gyre 02G11 Aug-Sept 2002

-93 -92 -91 -90 -89 -88 -87 

28 

29 

01

02

03

04 05

06

07 08

CTD Stations During D-Tag Cruise (R/V Gyre 02G11) Aug-Sept-2002

200m, 1000m, and 2000m isobaths shown
51

Table 3.2.6

Location, time, cast depth and water depth for SeaCat CTD casts taken on the SWSS 2002 D-tag

cruise

Station Date Time Latitude Longitude Cast Water

CTD-01 08/22/2 18:20 28.3067 -89.5000 942 945

CTD-02 08/25/2 10:30 28.2057 -89.3728 1007 1016

CTD-03 08/28/2 06:32 28.6651 -88.9305 944 946

CTD-04 08/29/2 05:16 28.8713 -88.6562 664 667

CTD-05 09/04/2 22:48 28.7812 -88.4505 1360 1371

CTD-06 09/12/2 13:09 28.9294 -88.5142 719 735

CTD-07 09/13/2 12:47 27.5648 -91.1142 941 959

CTD-08 09/14/2 22:38 27.6495 -92.7576 719 730

Mean sound speed profiles based on the XBT and limited CTD data were provided to the tag and

passive acoustics personnel for use in their acoustic calculations. These were used to obtain

estimates of sound speed profiles to assist in extracting precision information from the D-tags.

Furthermore, most whales were found along the rather complex frontal boundaries of the

Mississippi River plume. Here is where sound speed profiles are likely to differ most from

historical averages.

Because of the nature of the controlled exposure experiment, it seemed prudent to reduce

extraneous sound sources. The two ADCPs (153 kHz and 38 kHz) were turned off whenever

whales were present and were operated only when making long (several hour) high speed runs

between locations. Figures 3.2.15 and 3.2.16 show the tracks (upper panels) over which the 153-

kHz and 38-kHz ADCP data were collected and the current velocity vectors from the surfacemost bin of each instrument (lower panels). Upon reaching a new location, the ADCPs were

secured as soon as the first whale was sighted. This action made it clear that the ADCP

operations did not interfere with the controlled exposure experiments because they were not

operational during the experiments. Data from the long runs should provide an idea of the

general circulation patterns over the area between Mississippi and DeSoto Canyons.

Additionally, no good data were lost under this method of operating because whale observations

generally were made in a 10-km box encompassing the whales that were being studied.

Continuous ADCP records within such boxes would have been unwieldy to process and of

limited use.

The Gyre has two continuously-fed flow-through systems that draw seawater in from ~3m depth.

One is located in the bow and measures temperature and salinity, and one is mid-ships and

monitors temperature, salinity, and fluorescence. These can be merged with DGPS time and

location to produce a continuous record of these parameters during the entire cruise. Water

samples were drawn from the mid-ship flow-through system and measured chemically for

chlorophyll concentration. Seventy-five such samples (Figure 3.2.17) were collected and

analyzed by Laurie Sindlinger (TAMU). The date, time, location, concentration, and subjective

ocean color observations for each chlorophyll are listed in Table 3.2.8. The color observations

alone show that we were operating in a frontal region between the relatively low-salinity highchlorophyll regions associated with Mississippi River outflow and the more saline "blue" waters

offshore.
52

Table 3.2.7

XBT probe deployment locations and dates on SWSS 2002 D-tag cruise

(The depth of the 15°C isotherm is given. T7 probes were used. Probes 9, 15, 19, and 27 had

good results only in the upper part of the cast; bad data from the lower part were removed.)

Station Latitude

(°N)

Longitude

(°W)

Date

(mm/dd/yyyy)

Time

(UTC)

Cast

Depth

(m)

Water

Depth

(m)

15°C

Depth

(m)

XBT-01 28.3348 -89.6663 08/15/2002 07:30 683 751 218

XBT-02 28.4311 -88.9999 08/25/2002 05:32 760 988 240

XBT-03 28.6146 -88.8329 08/25/2002 09:09 760 1136 260

XBT-04 28.6641 -88.9897 08/27/2002 18:18 662 802 247

XBT-05 28.9413 -88.4148 08/29/2002 07:26 760 873 191

XBT-06 29.0431 -87.9998 08/29/2002 10:02 760 1307 244

XBT-07 29.1349 -87.7478 08/29/2002 11:38 760 1247 220

XBT-08 29.2879 -87.4620 08/29/2002 16:38 760 834 223

XBT-09 28.6679 -88.9275 08/31/2002 14:20 532 953 215

XBT-10 28.6679 -88.9442 08/31/2002 14:36 760 910 208

XBT-11 28.9148 -88.2676 09/03/2002 19:44 760 1173 214

XBT-12 28.8639 -88.5732 09/04/2002 08:41 760 778 222

XBT-13 28.6658 -88.7501 09/05/2002 02:02 760 1233 236

XBT-14 28.5499 -89.0716 09/05/2002 04:38 620 623 250

XBT-15 28.4697 -89.2501 09/05/2002 06:10 531 532 227

XBT-16 28.3748 -89.5001 09/05/2002 08:13 697 728 223

XBT-17 27.7085 -88.9294 09/06/2002 18:56 653 1602 216

XBT-18 27.6789 -88.9638 09/06/2002 20:13 760 1727 206

XBT-19 27.6659 -89.0134 09/06/2002 21:10 760 1641 232

XBT-20 27.6645 -89.0177 09/06/2002 21:16 760 1634 236

XBT-21 27.6676 -89.0520 09/06/2002 22:46 760 1641 237

XBT-22 27.8383 -89.0720 09/07/2002 12:04 760 1393 234

XBT-23 27.9241 -89.0829 09/07/2002 12:44 760 1260 237

XBT-24 28.0000 -89.0959 09/07/2002 01:19 760 1332 235

XBT-25 28.1669 -89.1249 09/07/2002 02:36 760 1135 225

XBT-26 28.6684 -88.9244 09/09/2002 20:05 760 963 221

XBT-27 28.6431 -89.0073 09/11/2002 16:10 456 707 199

XBT-28 28.6425 -89.0184 09/11/2002 16:22 707 708 202

XBT-29 28.5402 -88.9841 09/12/2002 08:26 760 776 222

XBT-30 28.7071 -88.7685 09/12/2002 10:42 760 1140 199

XBT-31 28.6685 -88.7906 09/12/2002 19:11 760 1082 206

XBT-32 28.4855 -89.0074 09/12/2002 21:04 760 885 208

XBT-33 28.2211 -89.2722 09/12/2002 23:41 760 919 252

XBT-34 28.0060 -89.5350 09/13/2002 01:57 760 947 244

XBT-35 27.8531 -90.0006 09/13/2002 05:16 734 745 249

XBT-36 27.7183 -90.5077 09/13/2002 08:46 760 838 273

XBT-37 27.5813 -91.0002 09/13/2002 11:57 760 932 243

XBT-38 27.6307 -91.5000 09/13/2002 16:50 760 793 247

XBT-39 27.6559 -92.0178 09/13/2002 21:21 621 622 227
53

95°W 94°W 93°W 92°W 91°W 90°W 89°W 88°W 87°W 86°W

26°N 

27°N

28°N 

29°N 

30°N 

31°N 

10m

20m

100m

200m

1000m

Texas Louisiana Mississippi Alabama Florida

10

20

100

200

1000

Texas Louisiana Mississippi Alabama Florida

100 cm·s -1

95°W 94°W 93°W 92°W 91°W 90°W 89°W 88°W 87°W 86°W

26°N 

27°N

28°N 

29°N 

30°N 

31°N 

Figure 3.2.15. Data collection from the 153-kHz ADCP on the D-tag cruise from 22 August

through 13 September 2002. Shown are (upper) locations of the ADCP-measured

currents and (lower) the horizontal current velocity at 13.6-m depth.
54

95°W 94°W 93°W 92°W 91°W 90°W 89°W 88°W 87°W 86°W

26°N 

27°N

28°N 

29°N 

30°N 

31°N 

10m

20m

100m

200m

1000m

Texas Louisiana Mississippi Alabama Florida

95°W 94°W 93°W 92°W 91°W 90°W 89°W 88°W 87°W 86°W

26°N 

27°N

28°N 

29°N 

30°N 

31°N 

10m

20m

100m

200m

1000m

Texas Louisiana Mississippi Alabama Florida

100 cm·s -1

Figure 3.2.16. Data collection from the 38-kHz ADCP on the D-tag cruise from 22 August

through 13 September 2002. Shown are (upper) locations of the ADCP-measured

currents and (lower) the horizontal current velocity at 13.6-m depth.
55

-93 -92 -91 -90 -89 -88 -87 

28 

29 

200m, 1000m, and 2000m contours shown

Locations where Chlorophyll Samples were Collected and Analyzed

During the D-Tag Cruise (R/V Gyre 02G11) August-September 2002

Figure 3.2.17. Locations of near-surface chlorophyll samples during D-tag cruise in

August/September 2002. Seventy-five samples were taken.
56

Table 3.2.8

Extracted chlorophyll stations on the SWSS 2002 D-tag cruise

Sequence Date

(m/d/y)

Time

(UTC)

Longitude

(°W)

Latitude

(°N)

Extracted

CHL

(μg/L)

Ocean

Color

1 8/22/2002 18:01 -89.50 28.30 0.29 blue

2 8/23/2002 15:43 -89.65 28.30 0.36 very blue

3 8/24/2002 16:08 -89.60 28.25 0.28 very blue

4 8/24/2002 17:48 -89.47 28.32 0.27 very blue

5 8/24/2002 19:25 -89.38 28.20 0.25 very blue

6 8/25/2002 00:29 -89.37 28.20 0.32 very blue

7 8/25/2002 01:33 -89.10 28.37 0.23 very blue

8 8/25/2002 04:40 -88.85 28.55 0.18 very blue

9 8/25/2002 15:36 -88.63 28.75 0.37 blue

10 8/25/2002 23:14 -88.87 28.68 0.18 blue

11 8/26/2002 15:06 -88.92 28.67 1.28 green

12 8/26/2002 17:29 -88.98 28.65 0.81 green

13 8/26/2002 21:38 -89.00 28.65 1.66 green

14 8/27/2002 16:09 -88.98 28.65 0.77 green

15 8/27/2002 21:25 -88.97 28.65 0.6 green

16 8/28/2002 00:47 -88.98 28.65 0.46 green

17 8/28/2002 13:03 -88.47 28.87 0.59 green

18 8/28/2002 16:28 -88.48 28.88 0.26 green

19 8/28/2002 18:45 -88.52 28.88 1.28 green

20 8/29/2002 00:56 -88.68 28.82 0.40 green

21 8/29/2002 12:38 -87.60 29.18 0.27 very blue

22 8/29/2002 13:47 -87.57 29.22 0.35 very blue

23 8/29/2002 16:42 -87.43 29.30 0.31 very blue

24 8/29/2002 20:15 -87.47 29.23 0.27 very blue

25 8/29/2002 23:03 -87.65 29.20 0.25 very blue

26 8/30/2002 07:47 -88.25 29.63 0.77 green

27 8/30/2002 11:08 -88.67 29.95 0.47 green

28 8/31/2002 01:00 -88.87 28.93 0.51 green

29 8/31/2002 12:02 -88.88 28.73 0.27 very blue

30 8/31/2002 15:56 -88.73 28.82 0.35 very blue

31 8/31/2002 22:48 -88.73 28.82 0.23 very blue

32 9/01/2002 17:18 -88.40 28.97 0.27 blue

33 9/01/2002 22:42 -88.37 28.98 0.28 blue

34 9/02/2002 13:44 -88.57 28.88 0.85 green

35 9/02/2002 15:42 -88.57 28.92 1.83 green

36 9/02/2002 19:43 -88.50 28.87 0.44 blue

37 9/03/2002 13:12 -88.32 28.97 0.27 green

38 9/03/2002 17:23 -88.23 28.90 0.18 blue

39 9/03/2002 23:20 -88.40 28.92 4.04 very green

40 9/04/2002 13:38 -88.58 28.80 2.42 green

41 9/04/2002 19:33 -88.42 28.85 1.15 blue-green

42 9/04/2002 23:29 -88.45 28.77 1.19 blue-green

43 9/05/2002 02:42 -88.83 28.63 0.68 blue-green

44 9/06/2002 04:45 -89.10 28.53 0.51 blue-green

45 9/05/2002 07:47 -89.45 28.38 0.36 blue-green

46 9/05/2002 12:33 -89.57 28.33 0.33 blue-green

47 9/05/2002 21:43 -89.42 27.92 0.33 blue-green

48 9/06/2002 15:31 -88.93 27.65 0.32 blue

49 9/06/2002 19:42 -88.95 27.68 0.50 blue

50 9/06/2002 21:30 -89.02 27.65 0.28 blue

51 9/06/2002 22:42 -89.05 27.72 0.33 blue

52 9/07/2002 00:07 -89.07 27.85 0.29 blue

53 9/07/2002 02:47 -89.12 28.11 0.37 blue

54 9/07/2002 07:20 -89.02 28.47 0.51 blue
57

Table 3.2.8

Extracted chlorophyll stations on the SWSS 2002 D-tag cruise (continued)

Sequence Date Time

(UTC)

Longitude

(°W)

Latitude

(°N)

Extracted

CHL

(μg/L)

Ocean

Color

55 9/09/2002 17:32 -88.93 28.70 0.89 blue-green

56 9/09/2002 20:46 -88.95 28.68 0.85 blue-green

57 9/10/2002 00:44 -88.95 28.63 0.42 blue-green

58 9/10/2002 14:57 -88.88 28.68 0.64 green

59 9/10/2002 20:52 -88.88 28.50 0.29 green

60 9/11/2002 01:28 -88.87 28.42 0.35 green

61 9/11/2002 13:01 -88.88 28.67 3.77 green/brown

62 9/11/2002 18:28 -89.07 28.50 2.83 green/brown

63 9/11/2002 22:26 -89.12 28.43 0.51 green

64 9/12/2002 10:06 -88.83 28.65 1.19 blue-green

65 9/12/2002 10:40 -88.50 28.92 1.49 blue-green

66 9/12/2002 13:11 -88.48 28.93 0.64 blue-green

67 9/12/2002 23:27 -89.25 28.23 0.15 azure blue

68 9/13/2002 01:01 -89.42 28.08 0.25 azure blue

69 9/13/2002 05:32 -90.03 27.83 0.15 azure blue

70 9/13/2002 06:59 -90.23 27.78 0.14 azure blue

71 9/13/2002 08:53 -90.52 27.70 0.12 azure blue

72 9/13/2002 11:18 -90.88 27.60 0.14 azure blue

73 9/13/2002 12:48 -91.10 27.55 0.16 azure blue

74 9/13/2002 17:19 -91.57 27.62 0.17 azure blue

75 9/13/2002 21:54 -92.07 27.65 0.13 azure blue

While at sea, four SSH fields, produced by Robert Leben of the University of Colorado, were

received. These fields represented conditions for 21 August, 28 August, 4 September, and 10

September. All four are similar. The field for 10 September is shown in Figure 3.2.18. The SSH

field shows a fairly strong cyclonic flow southeast of the mouth of the Mississippi River

separating two moderate regions of anticyclonic flow over the Mississippi and DeSoto Canyons.

This configuration should produce offshore flow near 90°W and onshore flow near 88°W. A

SeaWiFS image for 24 August also was received, courtesy of Orbimage and NASA and

processed by the College of Marine Science of the University of South Florida. Figure 3.2.19

shows the ship track color-coded to reflect near-surface salinity (blue is low salinity, pink is

higher) from the flow-through system overlain on this SeaWiFS image, which is indicative of

chlorophyll levels in surface waters (red is high, purple is low). The region of blue imbedded in

purple south of the delta is a region of apparent cyclonic flow. The image suggests the notion

that we were finding whales in the frontal regions. High salinities correlate well with low

chlorophyll waters found offshore as do low salinities with high-chlorophyll waters associated

with the river plume. Also, the fact that there is some movement of the frontal boundaries is seen

in changes with time of salinity from the ship tracks in the same area.
58

Figure 3.2.18. Sea surface height from TOPEX/ERS-2 altimeters for 10 September 2002. Image

is from Robert Leben, Colorado Center for Astrodynamics Research (CCAR),

University of Colorado.
59

Figure 3.2.19. SeaWiFS image for 24 August 2002 showing chlorophyll concentration and D-tag

cruise track color-coded to salinity. For chlorophyll, red is a high concentration

and purple is low. For salinity, red is high and blue is low. SeaWiFS image is

courtesy of Orbilmage and NASA; data were collected and processed at the

College of Marine Sciences, University of South Florida.
60

3.3 S-tag Follow-up Cruises

S-tag follow-up cruises were conducted 6-8 December 2002 and 19 January-2 February 2003

from sport fishing vessels based out of Venice, LA. Sperm whale surveys were conducted in this

area with the objectives to relocate tagged sperm whales and to make observations on the tag

healing process, possible tag effects, and association between individuals through photoidentification. Surveys were done on board the 36' Delta Dawn and 26' Prime Time fishing

vessels. Information on the December cruises is summarized in this report.

The locations of tagged sperm whales were determined from satellite transmissions received

from late November through early December 2002 (Figure 3.3.1a). These locations showed

many of the whales with operating tags were located off the mouth of the Mississippi River in

water depths greater than 200 m. Note the close proximity of the whales to the coast in that

region. This proved advantageous because no long transits were needed to make the

observations. The track of the survey was based on these locations (Figure 3.3.1b).

The participants in the survey were Joel Ortega and Dan Lewer of OSU. During the survey, the

two observers searched for sperm whales by naked eye and with hand held binoculars.

Additionally, a hydrophone was deployed at several locations to detect sperm whale

vocalizations. Weather conditions were marginal throughout the survey period.

A group of three sperm whales was observed on 7 December 2002 at latitude 28.7288 ̊N and

longitude 88.9558 ̊ (Figure 3.3.1b). The group consisted of two adults and a juvenile. The whales

were approached closely enough to detect the presence of tags; they did not have tags attached.

One of the adults had a lump on the dorsum, about 20 cm in front of and 30 cm to the left of the

dorsal fin. This protuberance was about 30 cm on the dorsoventral axis and about 15 cm on the

sagittal axis. No blood or secretions were observed coming from the lump and the animal did not

exhibit any unusual behavior during the time it was observed (about 8 minutes). From its

location, it is possible the protuberance could have resulted from a tag previously being attached

to the whale. However, the actual cause of the lump is unknown, and no pictures were available

to allow positive identification as a tagged whale. Video and pictures were taken of all the

observed individuals, including some video footage of the lump. However, due to the

environmental conditions, it was not possible to obtain pictures suitable for individual

identification.

Additional efforts to relocate tagged sperm whales off the mouth of the Mississippi River began

in January 2003. These will be reported on in the next annual report.
61

Venice, LA

South Pass

50 km

89.5°W 89.0°W 88.5°W

28.5°N

29.0°N

29.5°N

89.5°W 89.0°W 88.5°W

28.5°N

29.0°N

29.5°N 50 km

1000 m 200 m

Venice, LA

South Pass

1000 m

200 m

(a)

(b)

Figure 3.3.1. S-tag follow-up cruises activities. Shown are (a) location of satellite transmissions

(crosses) from sperm whales near the mouth of the Mississippi River from 29

November through 4 December 2002. (b) Trackline of the survey effort conducted

on 7 December 2002. Crosses indicate the locations of sperm whale sightings.
63

4 INSTRUMENTATION AND DATA METHODS

4.1 RHIBs

Three small boats were used during the SWSS 2002 cruise. For the S-tag leg, two boats were

used: one as the tag boat and one as a support and photo-ID boat. The tag boat was the OSU

boat, Puffin, which is a 6.4-m, 3400-pound, rigid hulled inflatable boat with diesel powered,

engines. To provide a replacement for the MMS R2 tag boat, which was not available for the Stag cruise, the Puffin was refurbished by OSU for use on the S-tag cruise. It also was modified by

adding an extended bow pulpit to allow close approaches to tag sperm whales and, from the

added height, to allow a better vertical orientation of the antenna. The Puffin was launched from

the port side of Gyre using the ship's crane.

The support/photo-ID boat for the S-tag cruise was the Gyre's 14-foot Avon. This boat also is a

rigid hulled inflatable. It was crewed by two and sometimes three members of the scientific party

and was equipped with a palmtop computer linked to a GPS that allowed the detailed track of the

boat as well as the position of diving whales to be recorded accurately. Ranges to whales were

measured using Bushnell or Leica laser range finders. A simple, custom-made directional

hydrophone, which consisted of a single hydrophone and preamplifier within a reflective dish,

was used from the Avon to aid in tracking submerged whales. Considerable attention was given

to reducing the amount of noise that could telegraph through the structure and be picked up by

the hydrophone. The Avon was launched with the ship's crane.

For the D-tag leg, two boats also were used: one as the main tag boat and one as back up. The

primary tag boat was the MMS R2. The back-up boat was the OSU tag boat. The R2 is a 24-foot,

5000+ pound, rigid hulled inflatable boat with two gasoline-powered, 135hp Mercury Optimax

engines. It is fitted with electric trolling motors to minimize underwater sound during low speed

maneuvering and has a large foredeck for pole-based tagging. Because of the weight of the R2,

the Gyre's crane was not used to launch the boat; instead a custom launch ramp over the fantail

was constructed and used.

4.2 S-tag Instruments and Data Methods

4.2.1 Satellite Tag Data

Data Acquisition

The Argos Data Location and Collection System is used to track whales. This technique is

described more fully by Mate et al. (1997). Tags transmit ultra-high frequency (UHF) radio

signals (401.650 MHz) to Argos receivers on National Oceanic and Atmospheric Administration

(NOAA) television infra-red observation satellite (TIROS)-N weather satellites. The satellites

are in sun-synchronous polar orbits, with each one passing over the study area at different times

of the day three to six times daily, depending on latitude (more passes at higher latitudes). To

conserve power, we limited transmissions to select times (four 1-hr periods) when there was a

high probability of satellites being overhead. Locations are calculated by Service Argos from

Doppler shift of tag transmissions created by the speed of the satellite passing overhead (Fancy

et al., 1988).

Tags were applied with an air-powered applicator from a small rigid hulled inflatable boat. The

tags consist of Telonics transmitters (ST-15), housed in stainless steel (SS) cylinders (19 cm long

by 1.9 cm in diameter), and are designed for nearly complete implantation beneath the whale’s

skin. Double edged blades are mounted in one end of the tag with a flexible whip antenna and

saltwater conductivity switch mounted in the other end. Both endcaps are made of Delrin. A

series of thin, outwardly-curved SS strips are wrapped around the housings at the base of the
64

blades to prevent outward migration of the tags. Thin outwardly-curved SS wires are mounted

forward of these strips for additional anchorage. The antenna endcap has two perpendicular

projections to act as a stop, preventing inward migration of the tag. The tags have a

Methacrylate coating of long-dispersant (5–8 month) Gentomycin antibiotic. All tag components

are produced in the United States.

In addition to providing transmissions for location calculation, the tags report cumulative number

of surfacings, which help to interpret whale behavior. As UHF radio signals rapidly attenuate in

seawater, the conductivity switch on the tag determines when whales are at the surface before

initiating transmissions. While at the surface, tags are capable of transmitting once every 10

seconds. Anticipated life expectancy is adjustable depending on the transmission duty cycle and

the extent of the whale’s surface behavior, with a maximum expectancy of one year.

Data from Service Argos are plotted using ArcView® geographic information system (GIS)

software. The accuracy of Argos-acquired locations is evaluated with screening criteria to

eliminate locations with unacceptable errors.

S-tag Processing Methods

Location Data: Locations of the S-Tags are computed by Service Argos by calculating the

Doppler effect on received frequencies. The accuracies of the locations are stated in terms of

location “classes” and are assigned by Service Argos. All locations are examined by OSU

researchers and initially checked for plausibility by computing the speed between sequential

locations. If the speed is below a realistic maximum (for sperm whales a maximum speed of

15k/h is used) the location is retained.

However, if the speed between two locations is greater than the maximum, a radial buffer equal

to the accuracy for the location class is applied to each location in order to compensate for errors.

The speed is then recalculated after shifting the two locations towards each other by one buffer

width. If the speed is still greater than the maximum, one of the two locations is removed.

Criteria such as location class, whether one location is on land, and which location results in

minimum speed are used to determine which locations to remove and retain.

Locations that map on land (a rare event) have the same radial buffer equal to the accuracy for

the location class applied to compensate for error. If there is navigable ocean within the buffer

then the location is retained. Locations within 1 hr of each other are also closely examined and

only one is retained if the accuracies are low.

Sensor Data: The salt-water switch on the S-Tag is polled every 0.25 seconds. When the switch

registers “dry” after having been “wet”, a counter is incremented. The counter value is sent in

duplicate within the data stream of the transmission. Raw values are received from Service

Argos and only those that meet the redundancy check are used.

4.2.2 Acoustic and Visual Observations

Passive Acoustic Observations

Passive acoustic monitoring was the principal means for finding and following sperm whales on

all the SWSS legs as well as being a source of information on the behavior of sperm whales and

their responses. To this end simple but effective towed hydrophone systems were provided for

the Gyre on both legs.

Passive Acoustics Equipment: Figure 4.2.1 outlines the monitoring system. Two systems were

used. One, provided by WHOI had a 150-m tow cable and was designed to work in conjunction

with a "batfish" depressor to allow the hydrophone to be deployed at greater depths. A second

system, assembled by Ecologic, had no depressor, the streamer had a 400-m tow cable and was
65

depressed solely by the weight of the cable. It typically towed at around 9-m depth. The arrays

had similar hydrophone streamer sections consisting of 2 (Ecologic) or 3 (WHOI) hydrophone

elements mounted about 3 m apart and housed in a polyurethane tube that was about 10 m long.

Both streamers were deployed from winches on the Gyre. It was found that the depressor on the

WHOI system vibrated at speeds of 5 knots and over and this limited its efficacy for everyday

use.

Signals from the streamers were brought to an "Acoustic Lab" on the upper science deck of the

Gyre where they were amplified and filtered using custom electronics before being digitized and

further processed on a PC. The Acoustic Lab was established in a dry lab aft of the computer

room on the 01 deck of Gyre. During days when groups of whales were being tracked for tagging

and photo-ID, a second, open-air acoustic monitoring station was established on the flying

bridge. This topside station facilitated the coordination of visual and acoustic information on

whale locations during these periods.

Typical Monitoring and Data Collection: During the S-tag leg, hydrophones were monitored

round the clock by a four-person acoustic monitoring team. Various acoustic analysis and

detection programs were also run and monitored continuously. The most useful of these were

Ishmael, written by Dave Mellinger of Oregon State University, and Rainbow Click, developed

by Douglas Gillespie at the International Fund for Animal Welfare (IFAW). Both of these

programs provided a real-time visual representation of the sound being monitored and gave

bearings to signals. Every 15 minutes the member of the acoustic team on watch listened

critically to the hydrophones and noted down their subjective score of the strength (on a 0-5

scale) of a variety of background noise sources and of various cetacean vocalizations. To achieve

scoring consistency monitors used a browser-based training CD before the project began and

also compared within the team how they scored different sounds during the course of the

fieldwork. These data were entered into an "Acoustic Monitor" database using the Logger

program. The ship's location and its research/monitoring activities were also recorded in this

database. Of particular importance was to record whether the vessel could be considered to be

collecting "survey" data as opposed to actively following whales or, as was often the case, being

directed towards known or supposed areas of high whale abundance.

Recordings and Detection Programs: Logger was configured to make regular acoustic

recordings, a 20-second sample recording once every 2 minutes. These were made in stereo at a

48kHz sampling rate and were initially stored on the computer's hard disk before being copied to

two sets of CDs. Logger maintained a table within the Acoustic Monitor database detailing these

sample recordings. As these files were copied to backup CDs, entries identifying the backup CDs

were made in the database.

In addition, longer recordings were made at any time when sounds deemed worthy of recording

were heard. These included recordings in the presence of socializing groups, which typically

contained codas, recordings of other identified cetaceans encountered in the area recordings of

anthropogenic sounds.

The automated click detection program "Rainbow Click" was run continuously. Rainbow Click

provides information on the number of animals clicking and the relative bearings at which

signals arrive at the streamer (with a left-right ambiguity) and was a useful acoustic tracking tool.

The Rainbow Click output files were stored and backed up to CD. These files contain a

continuous record containing the waveform and bearing information for every transient detected

by the program.

Small Boat Acoustic Tracking and Monitoring: Passive acoustic systems on the RHIBs were

used for fine scale tracking on whales. Custom-built directional hydrophones were employed for

this. The simplicity of the equipment, essentially a shielded hydrophone which was rotated by
66

Figure 4.2.1. Diagrammatic representation of underwater and topside components of the

acoustic monitoring system.

hand until the whale’s clicks sounded loudest, was balanced by the fact that the RHIBs could

respond quickly to information, moving on acoustic bearings to reposition and monitor again.

The technique was most effective when acoustic information from the small boats was used in

conjunction with visual and acoustic data from the Gyre.

On some occasions, in particular when the Gyre had no acoustic contact with whales on a day of

good weather, the RHIBs were launched and used to scout ahead and to the side of the Gyre.

Because the RHIBs could be shut down to monitor they were much quieter platforms than the

Gyre and they could also move more quickly and cover a lot of ground. This use had not been

anticipated and the available equipment was not as good as appropriate as it could be, even so

use of the RHIBs seemed to significantly increase combined acoustic effectiveness.

Acoustic Data Summary: The acoustic data collected during the project consist of four parts

1. the monitor's summaries of standardized monitoring sessions,

2. regular acoustic samples and more extended recordings as a series of wav files,

3. near continuous summary of transient detection by Rainbow Click, and

4. information on acoustic monitoring effort and vessel acoustic survey activity.

400m Tow

Cable

Rope Tail Preamplifier

Polyurethane

Tube Depth Sensor

Hydrophone

Element

Amplifier/

Conditioner

Headphones Recording/Analysis

Computer

Onboard “Gyre”

400m Tow

Cable
67

These data were either stored within or referenced by an integrated Access database built upon

the database created during the project by the Logger program. All data were backed up on two

series of CDs, one of which was archived with the Data Office at TAMU Department of

Oceanography.

Visual Observations

A visual observation station was established at the highest, unobstructed point possible on the

ship, which on the Gyre was on the flying bridge. It consisted of three stand-mounted BigEye

binoculars and a data entry station. A team of at least three observers maintained a continuous

watch during daylight hours (06:30-19:30 CDT) when the ship transited or surveyed in water

depths greater than about 500 m. Two of the observers were on BigEye binoculars while the

third person (the data recorder) kept watch closer-in with naked eye and with 7x50 binoculars.

This third person also entered data into a laptop computer running Logger software. Logger is a

data collection and depiction program written by Douglas Gillespie and made available by the

International Fund for Animal Welfare. A digital video camera was mounted on a third pair of

BigEyes and was used opportunistically to collect accurate range and bearing for the video

recordings and to document detailed animal movements and behavior.

The visual team on the flying bridge worked in different modes depending on the vessel's

activity. When searching for whales or surveying, the team searched using BigEye binoculars,

7x50 binoculars, and the naked eye following a line-transect survey protocol. Data on search

effort, vessel status, weather condition, and sightings were stored in a Visual Database using the

Logger Program. Logger also stored various data from the ship's NMEA line.

Once whales had been detected the task of the visual team was to track the location and

movements of whales at the surface, to integrate this information along with acoustic data from

the Gyre's acoustic team and data from the small boats, and to guide the small boats on to whales

sighted at the surface or into areas in which they were likely to surface.

The surface location and heading of every whale was fixed when it was first seen and when it

submerged by measuring its range and relative bearing. Range was determined by measuring the

number of reticules in the BigEye's eye-piece "beneath" the horizon for each whale, a visual

basic program "gratran" calculated range from reticules and made this available to the Logger

program. Relative bearing measurements were made from the Big-Eye's bearing rings. These

data were entered into forms within Logger, which also displayed whale locations and the ship's

track in real time on a map.

Photo ID

Equipment: The majority of the photo-identification images were collected with a digital SLR

camera (Canon EOS1D SLR and Sigma 100-300mm f4 lens). This system gave excellent

results. The camera was able to shoot at 8 frames per second and freed from concerns about the

cost of film we chose to take extended sequences of every fluke up. This contributed to better

quality images than usual. Other advantages of digital included the ability to review images

every evening, so that any problems with equipment or technique could be rectified and work

could begin immediately to build a local catalogue and make comparisons with existing

collections.

Most dedicated photo-ID effort was conducted from the Gyre's smaller RHIB rather than the

larger OSU RHIB. This worked well, although its lively motion made protecting camera gear

from splashes and taking good images challenging. The Gyre RHIB was equipped with a Hewlet

Packard palm top PC linked to a GPS running a customized data collection program. This

allowed information on group sizes, locations and behavior for the animals being photographed

to be noted consistently on a small lively vessel.
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Photo-identification was a secondary activity to the cruise's main goal of satellite tagging. Even

so, the value for effective photo-ID of having a strong visual and acoustic team on the Gyre's

flying bridge to coordinate the movements of the RHIBs, allowing them to sample effectively a

larger dispersed group, became apparent.

Photogrammetry: A simple method was employed to measure the size of whales encountered.

Photo-ID images were taken from directly behind the whales at a range at which the lens could

be used at maximum zoom. The range from the photographer to the whale was measured using

Bushnell or Leica range finding binoculars and cases in which the photographer was not directly

behind the whale at fluke up were noted and discarded. The focal length of the lens was

calibrated using test objects so that when range and fluke size on the image are known fluke span

can be determined. Whaling data were used to derive a relationship between fluke span and body

length.

Information on the identity and location of appropriate length estimation images are stored in the

visual database. Substantial datasets of length images from the same whale will be required to

test the reliability of this method.

Data Assurance and Quality Control

All acoustic, visual, and photo-ID data were copied on two duplicate sets of CDs, one of which

was archived with the Data Office at TAMU Department of Oceanography.

Any large dataset contains errors and dealing with these is an ongoing process. Mistakes made or

problems encountered during data input were noted as comments within the database. These

were rectified before the end of the field project. Visual basic routines were written and run on

the dataset to detect and fix particular common errors. For example, problems with the GPS

interface often resulted in blank or spurious location data being stored. Other errors or problems

may be found in the course of analysis. Those involved in analysis fix these errors as they arise

and exchange updated datasets with co-workers to ensure that a single "best" visual and acoustic

dataset is available. This improved dataset will be archived at TAMU Oceanography from time

to time.

Acoustic Data: Regular monitoring sessions made while following sperm whales on which

seismic pulses can be detected have been extracted and the bearing to seismic pulses has been

measured using Ishmael. These data have been incorporated into the Acoustic Database.

Analysis of sperm whale codas (stereotyped patterns of clicks which are often heard in social

contexts) is ongoing. Analysis results in Rainbow Click files in which codas are identified and

labeled and, as far as possible, the individual whales making codas is indicated. Data

summarizing coda parameters can be readily extracted from these analyzed files using Rainbow

Click. The identity and location of coda wav files and analyzed rainbow-click files are stored

within the Acoustic Database.

Photo-ID and Photogrammetry: Photogrammerty images have been analyzed. Locations of

images and results of analysis are stored within the Visual database. A larger dataset of images

are required to test the reliability of this new method.

Image Archiving: All raw digital images are archived at TAMU Oceanography on CD.

Selections of the digital images useful for photo-ID and digitized copies of the photo-ID images

taken on film stock are maintained within a local photo-ID catalogue. Each image is scored for

quality using a well-established method. The "type images" for each individual within this

catalogue are shared with other sperm whale researchers through the North Atlantic and

Mediterranean Sperm Whale Catalogue.
69

4.3 D-tag Instruments and Data Methods

4.3.1 Digital Acoustics Tag Data Acquisition

The D-tag was developed by WHOI principal investigators in 1999. Details on its design are in

Johnson and Tyack (2003). The D-tag is used to measure the exposure level received by a target

animal, and document its reaction. This non-invasive tag records the sounds heard, and made, by

the tagged whale together with its depth and orientation (i.e., pitch, roll, and heading), in a

synchronized fashion throughout the dive cycle (Caldwell, 2002; Johnson and Tyack, 2003).

The tag records data digitally for between 10 and 24 hours, depending on sampling rate, with

enough resolution to track individual fluke strokes (Nowacek et al., 2001). The D-tag is cast in

epoxy for robustness and is attached to the whale with suction cups. A cantilevered-pole,

approximately 40' long, is used to deliver the tag to the whale, minimizing the impact of tagging.

Intensive visual and acoustic observations from a nearby research vessel record the social and

geographical context of the whales' behavior, before, during, and after tagging. The sensitivity of

the D-tag allows a wide range of exposure levels to be tested: D-tags on sperm whales in the

northern Gulf have recorded survey sounds at a range of 15 miles with excellent fidelity.

Tagging Method: Once whales are located and the research vessel has moved close to the

animals, a RHIB is deployed with a 4-person tagging team to attach D-tags to whales. Once the

RHIB is deployed, a directional hydrophone is used to locate and close on sperm whales. Visual

and acoustic observers on the research vessel support the tagging effort by providing surfacing

positions and acoustic bearings of whales to the RHIB team. Where possible, multiple animals

are tagged prior to each CEE to increase data gathering efficiency and to minimize habituation.

After attaching a tag, the length of the whale is measured using photogrammetry and

photographs of the fluke and other distinguishing features are taken for photo-identification if

this has not already been accomplished. The whale’s surfacing location is inspected to search for

feces or skin. Once a whale has been tagged and photographed, the RHIB either returns to the

research vessel or attempts to tag another whale. The number of whales tagged before each CEE

depends on the likely attachment duration, the group composition, and our ability to adequately

observe multiple animals. No more than three whales are tagged at one time.

4.3.2 Controlled Exposure Experiments

The primary goal of the controlled exposure experiments is to measure the sensitivity of sperm

whales to disturbance from airgun sources. Subsets of animals are exposed to an airgun source

and/or to a biologically-relevant sound likely to elicit a response (e.g., a 'coda’, Watkins et al.,

1985). This approach ensures detailed and replicated measurements of response suitable for

statistical treatment. Sounds from both a closing fully-powered array and from an array in softstart will be tested with the initial focus on the latter.

One of two sound sources is used: airguns (either a fully-powered array or an array in soft-start),

and the playback of a previously recorded sperm whale coda as a biologically-relevant control.

As an additional control, a sub-set of tagged animals receives no sound exposure.

The three phases of the CEE are:

1. Pre-exposure: Once the desired number of tags are deployed, a pre-exposure period of

approximately 2 hours is planned to record baseline behavior of the tagged whales and to move

the source vessel into the appropriate position. For deep-diving animals, a 2 hour baseline period

amounts to about 2 dives (3 surfacings), sufficient to establish some parameters of foraging

activity and to predict swim speed and heading. Visual observers on the research vessel track the

tagged whale(s) from a distance and note the positions of other animals in the group. Range from

the ship to each surfacing whale is determined by measuring the declination from the horizon
70

using big-eye binoculars. All visual data are entered in real-time into Logger, a data gathering

program, and displayed to aid positioning of the source vessel relative to the whales. Acoustic

observers coordinate with the visual team to continue tracking whales while underwater. By

combining visual and acoustic observations, a detailed real-time track of each tagged animal will

be built up from which the exposure level can be deduced and so the CEE can be controlled.

2. Exposure: After the prescribed pre-exposure period, and when the source vessel is in the

appropriate position, one of three sounds will be presented to the tagged whale(s): no sound

(baseline), coda playbacks (biologically-relevant control), or transmissions from an airgun array

as described below. Transmission duration is up to 2 hours, sufficient to document whale

reactions during 2 deep-dives. The choice of sound to transmit is determined by the availability

of the seismic source vessel and by the need for a statistically significant number of trials of each

exposure. Visual and acoustic observations continue during exposure both to qualify the tag data

and to ensure mitigation in the event of a strong reaction. In year 1, the primary goal is to

measure the behavior of sperm whales during the soft-start onset of an airgun array relative to

base-line and biologically-relevant sound exposures.

Following the protocol outlined in WHOI's Federal permit to conduct this research, the target for

a received level (RL) at the whale is 120-140 dB re 1μPa in the first year. The target RL may be

increased during the course of the study if little response is detected to trials at the initial level.

The conditions of the Federal permit under which this research is conducted limit the exposure of

whales to an RL <180dB re 1μPa. Transmissions will be halted if any whale is detected visually

or acoustically in areas where they may be exposed to levels above those allowed by the permit.

To this end visual observers are stationed on the source vessel in cooperation with IAGC. For the

biologically-relevant control sound, a broadband underwater source will be deployed off the

research vessel or tagging vessel to play coda sounds to tagged whales.

The choice of target RL throughout the program is made as follows. The CEE is started with an

RL known to be safe. Preliminary observations of sperm whales exposed to seismic survey show

contradictory results, with some animals silencing or avoiding a source and others showing little

obvious reaction to RLs in the 120-140 dB range. This suggests an initial target RL of 120-140

dB for airgun sounds, which is the initial target level specified in our Federal permit. The source

level for a single airgun is around 215-230 dB implying that, under expected propagation

conditions, the source vessel should maintain a range to the tagged whale(s) of some 10s of km.

A similar range would be needed for horizontal propagation of a seismic array. Sperm whales

will be tagged, if possible, in both Delta and Canyon areas and will include members of family

groups and lone males. If whale responses to the first several exposures are consistently weak,

we would consider raising the target RL (to say 140-160 dB) in the subsequent days of summer

2002 fieldwork. If we see predictable responses within the target range of RLs, we will continue

playbacks at that level until we have enough data to estimate the biological significance of the

responses.

3. Post-exposure: After the 2-hour sound transmission, visual and acoustic observations will

continue. The tagged whale(s) will be tracked and the positions of animals nearby recorded.

Post-exposure observations will continue until all D-tags have detached from the subject whales.

D-tags will then be recovered using the RHIB, and data will be downloaded from the tags in

preparation for the next experiment.

4.3.3 Visual and Acoustic Observations

Detailed visual observations and passive acoustic monitoring complement the D-tag data.

Previous research with sperm whales highlights the need to follow tagged whales, and other

whales nearby, both visually and with passive acoustics before a controlled exposure is

attempted. It is critical to know in real-time where whales are in order to predict the received
71

level at the whales for a sound exposure. In addition, merging data from the tag with visual

observations and passive acoustic monitoring, yields much more valuable data than would any

single approach (Zimmer et al., 2002). Observations are performed before, during, and

immediately after each CEE.

The research vessel is outfitted with high-power ("BigEye") binoculars. The visual/acoustics

team interfaces with ship's engineers to assure that visual locations of whales are available realtime using the computer software program "Logger" that has been successfully used both in the

Gulf of Mexico and the Mediterranean to track and locate whales in real-time. WHOI personnel

manage the visual observation team and train the rest of the observers in the use of BigEye

binoculars to track whales. A multi-channel towable hydrophone array with appropriate deckcabling, sound recording equipment and real-time acoustic data analysis systems is provided.

Acoustic signals are recorded on TASCAM digital recorders for detailed analysis after the

experiment, and are digitally streamed into PC’s for real-time analysis of acoustic bearing during

the experiment using Ishmael or Rainbow click software. WHOI personnel install and test array

equipment and assure that real-time analysis systems are operating.

During the search phase of operations, sperm whales are located using visual and acoustic

techniques. Visual observers scan for whales using BigEye binoculars, and acoustic observers

attempt to detect and locate sperm whales by listening for their vocalizations on a towed

hydrophone array. Once whales are detected, the research vessel is steered toward the whales,

and visual observers record the numbers and distribution of the group of animals. The acoustic

observers commence to track submerged whales in preparation for tagging and record array

signals to multi-channel digital recorders.

4.3.4 Data Analysis

The following checklist describes the different data streams collected during D-tag operations,

how the data are collected, how data are checked and archived in the field, and how data are

further archived, checked and analyzed in the lab. It does not report on synthesis-types of data

analyses where data from the different data streams are analyzed together. A copy of the Data are

provided to SWSS data management after each cruise.

1. D-tag Data: These data consist of the animal's depth, sounds heard on tag, temperature, and

magnetometer and accelerometer data on the whale. D-tag data are recorded on the tag after

attachment to the whale using suction cups. Data are offloaded to a PC using an infra-red link.

To check the data quality check in field, raw D-tag data first are converted to raw sensor and

acoustic data. The entire sensor record then is checked in MATLAB for quality to assure its

completeness and confirm start and end times. The acoustic record is sampled to assure quality.

At least 2 copies of the raw D-tag data are archived in the field on CD. In the lab, additional

archiving occurs. Four complete D-tag data sets on CD and other copies on hard-drive are held

by each of the project principal investigators with a fourth copy held in WHOI’s marine mammal

center managed by Research Associate Nicoletta Biassoni. Data are checked and analyzed in lab.

Sensor data are analyzed as reported in Johnson and Tyack (2003). Acoustic records are

completely audited to produce a catalog of sounds produced by the tagged whale as well as other

natural and man-made (i.e. seismics) sounds recorded by the tag.

2. Permit Data/Close Observations from RHIB: These data include tagging location, reaction of

the whale to tagging, tag placement, videogrammetry, and fluke identification. These data are

collected using visual observations of the reaction of the whale to tagging, digital video

recordings of tagging, fluke-out, and broadside video with laser range-finder. Visual

observations are recorded on data sheets. Quality checks in the field begin with double-checking

the data on the data sheets to assure completeness and that all whale ID’s match those used by

visual observers. Data sheets are copied in the field for archival. Video recordings are streamed
72

into computer using FireWire and back-ups made on CD. Fluke-shots and other images are

extracted as high-quality bit-map images. In the lab for archival, videotapes are stored in the

marine mammal center at WHOI. At least one additional CD archive is created. Data sheets are

scanned into PDF files. In the lab, data are analyzed as needed to support tag-data analysis.

Fluke-ID shots are catalogued separately. Video-length analyses are completed in MATLAB.

Permit reports of each whale approach are generated for reporting purposes to NMFS.

3. Skin/Fecal Data: These data consist of the sex of the whale and diet information. Feces or

sloughed skin material is collected during close approached to whales using a dip-net or small

plankton tow-net. Skin also is found occasionally on the D-tag suction cups after tag recovery.

For quality checks in the field, data sheets are used to record the location and ID from which the

material was collected. Tissue is carefully handled with sterilized procedures and placed in

prepared DMSO vials or frozen in zip-loc bags. A genetics expert, such as Dan Engelhaupt,

collects separate data-sheets with archival information. In the lab, skin tissue is analyzed to

determine the sex of the tagged whale. Genetic expert Dan Engelhaupt performs other genetic

analyses. Squid beaks are forwarded to an expert for species identification.

4. Visual Data: Included are whale locations, locations of the source vessel, and playback

condition. Data are recorded on 2 laptops located on the flying bridge running Logger software

provided free by IFAW. Locations of whales and of the seismic source vessel are determined

using BigEye binoculars to calculate the relative bearing and reticle to the whale. VHF tracking

of tagged whales aids in the identification of tagged whales at the surface. Logger integrates this

information with the NMEA stream to create a real-time plot of sighting locations. Playback

condition is recorded in Logger, and group-id notes and other comments may be recorded on

paper data-sheets. For quality checks in the field, Logger data records are checked daily to assure

that group ID’s are correct, and that focal whales were correctly identified. Data on animal tracks

are extracted from Logger records into Excel for export into MATLAB. At least 2 copies of raw

Logger data are archived in the field on CD. In the lab, at least one additional CD archive is

created. Data sheets are scanned into PDF files. For data checks and analysis in the lab, surfacing

locations of whales are plotted in MATLAB or Arcview and integrated with positions of the

observation-boat and source-boat.

5. Acoustic Data: These are the sounds heard from the observation vessel. Raw acoustic data are

recorded on multi-channel TASCAM recorders or direct-to-hard disk recording. Bearings to

whales are computed in real time using Rainbow Click software provided by IFAW. Notes on

tracking and acoustic activity levels are recorded on a laptop located in the acoustic lab running

Logger software provided free by IFAW. Playback condition is recorded in Logger, some notes

on tape number and other information are recorded on paper. For a quality check in field, Logger

data records are checked daily to assure that group ID’s are correct. Samples of data recorded to

hard disc are inspected. At least 2 copies of raw Logger data are archived in the field on CD. In

the lab, at least one additional CD archive is created. Data sheets are scanned into PDF files.

Raw acoustic recordings are copied onto a back-up TASCAM tape or streamed directly to harddisk. For data checks and analysis in the lab, data that are transferred to hard-disk are used for

passive tracking and to link acoustic activity to sounds recorded on the tag.

6. Source-vessel Data: These are the source-boat locations, playback condition, and mitigation

detections. Mitigation detections are made using a passive towed array running Rainbow click

and/or by visual observers using naked eye or hand-held binoculars. Data are recorded on a

laptop located in the acoustics lab running Logger software provided free by IFAW with a

NMEA stream connection. Locations of the source vessel, playback condition (including number

of airguns firing), and detections of marine mammals are recorded in Logger. Data sheets are

filled out for permit compliance. In the field, Logger data records are checked daily to assure that

group IDs are correct, and for completeness. At least 2 copies of raw Logger data archived in the

field on CD. In the lab, at least one additional CD archive is created. Data sheets are copied and
73

scanned into PDF files. For data checks and analysis in lab, surfacing locations of whales are

plotted in MATLAB or Arcview and integrated with positions of the observation-boat and

source-boat.

4.4 Genetic Analyses Methods

Biopsy sampling has been done extensively on a variety of cetacean species (Palsboll et al.,

1991; Weinrich et al., 1991; Baker et al., 1994; Weller et al., 1997; Hoelzel et al., 1998).

Previous work shows that it has minimal immediate effect on the animals and causes no long

term disturbance or problems with wound infection (Best and Butterworth, 1980; Brown et al.,

1991; Weinricht et al., 1991; Weller et al., 1997). In this study, detailed data sheets and

opportunistic digital video are used to record descriptions of the behavioral responses to biopsy

sampling. Previous findings show that approximately 70% of whales show no surface reactions

to the dart making contact. To account for the bias created by high kinship within a particular

group, sampling efforts will include multiple groups from different locations. At the same time,

multiple samples are included from some groups to assess kinship patterns within compared to

between groups. Differences in group size indicate that there could be differences in the pattern

of intergroup kinship to that seen by Richard et al. (1996).

4.4.1 Genetic Markers to be Analyzed

Three types of genetic markers will be analyzed in this study: the mtDNA control region,

microsatellite DNA loci, and the ZFXY locus for molecular sexing. DNA will be extracted from

tissue samples by standard phenol/chloroform extraction (Hoelzel, 1992). The mtDNA control

region will be amplified by PCR and include the region studied by Lyrholm et al. (1996).

MtDNA will be sequenced by automated ABI methods (David and Menotti-Raymond, 1998).

Microsatellite DNA will be analyzed using the Genotyper software for the ABI. Molecular

sexing is based on a PCR test that reveals different amplification products for males and females

on a standard ethidium bromide stained agarose gel. The three types of genetic markers and

methods associated with them are described briefly below.

1. MtDNA Analysis: We will analyze sequence variability in the mtDNA control region to

investigate whether there is differentiation among females occupying various regions of the Gulf

of Mexico and in comparison with other oceanic populations. Lyrholm et al. (1996) analyzed

variation among 37 sperm whale control region sequences and found 12 variable nucleotide sites

out of 954, identifying 13 mtDNA haplotypes. In all, a total of 25 lineages have been defined to

date (two unique haplotypes occurring in the Gulf of Mexico). We will sequence a 400 base pair

(bp) segment of the highly variable control region to provide greater resolution for population

discrimination within the Gulf and in surrounding waters.

2. Microsatellite DNA Analysis: Fifteen to twenty microsatellite loci will be analyzed, based on

published data (Richard et al., 1996; Lyrholm et al., 1999) and ongoing projects all using the

same 6-10 microsatellites (Sarah Mesnick, personal communication), which produced clear,

polymorphic amplification products. A genetic profile will be constructed for each sample by

scoring allele patterns at these loci. Additional loci allows for an increase in resolution required

for social structure questions. Information from previous studies suggests that sexually mature

males make temporary associations with matrifocal groups, which may mean that population

level variation will show less structure at these loci (which reflect the movement of both males

and females) than at mtDNA loci (which reflects only the movement of females). By utilizing the

same markers as other researchers, we can compare diversity at these loci on a global scale, as

well as within the Gulf. This allows us to better address our own questions and that of the species

at large.
74

3. Molecular Sexing: While there is significant sexual dimorphism present in this species as

whales reach maturity, the younger males and females can be difficult to distinguish in the field.

Some mature female sperm whales possess a callus (a whitish patch of thick, hardened tissue) on

the upper edge of the dorsal fin that appeared to be a strong indicator of sex (Kasuya and

Ohsumi, 1966). However, Chrystal (1998) has discovered that this is not always the case when

comparing calluses to genetic results and should therefore not be relied upon. Our determination

of sex for individual sperm whales has been performed using techniques described by Berube

and Palsboll (1996). This technique uses PCR and three oligonucleotide primers to amplify the

ZFX and the ZFY sequence in cetaceans. The resulting ZFX and ZFY amplification products

obtained can be distinguished by gel-electrophoresis through a 1.5% Agarose gel (stained with

ethidium bromide). After amplification using PCR, males will show two clear bands at

approximately 227 base pairs (bp) and 383 bp. Females will only show only one band at

approximately 383 bp. The Berube & Palsboll technique provides an internal control to ensure

that successful PCR amplification has taken place. Male and female stranded whales of known

sex are used as a control.

4.4.2 Genetic Data Analysis

Sequence alignments are generated using the Sequencher 4.1.2 sequence analysis package. The

computer software PAUP-star (Sinnaur, 1991) is used to analyze maximum parsimony,

neighbor-joining and maximum likelihood phylogenies of mtDNA sequence data both for the

Gulf region and for global diversity, incorporating published sequences from other geographic

regions. The computer software MEGA (Kumar et al., 1993) and Arlequin 2.0 were used to

estimate genetic distance (Dxy after Nei, 1987) between putative populations.

Nucleotide and haplotype diversities () are estimated as defined by Nei (1987). Tests for

heterogeneity are performed using a Markov chain permutation approach (Raymond and

Rousset, 1995) using Arlequin 2.0 software (Schneider et al., 2000). FST, an indication of the

amount of differentiation between compared to within populations, and estimates of gene flow

(Nm) are computed for both mtDNA and microsatellite DNA markers (e.g., Slatkin, 1995).

Population level comparisons include individuals from two datasets ('all' and 'restricted') to avoid

biases associated with the inclusion of close kin. Kinship assessment within and between groups

are determined using the programs Kinship and Relatedness (Queller and Goodnight, 1989).

4.5 Habitat Characterization Data Methods

4.5.1 Remote Sensing Fields

Remote sensing fields will be obtained from sites that routinely produce satellite sensor data

products. These include the sea surface height (SSH) fields produced by the Colorado Center for

Astrodynamics Research (CCAR) of the University of Colorado using data from the

TOPEX/POSEIDON and ERS-2 satellite altimeters (Leben et al., 2002), the sea surface

temperature (SST) fields produced from AVHRR satellite data by the Johns Hopkins University

Applied Physics Laboratory, and the ocean color maps made from data from the SeaWiFS

satellite by the Institute for Marine Remote Sensing at the College of Marine Science University

of South Florida. These fields will be used both as an aid for identification of circulation features

that might be of interest for the SWSS cruises and for analysis of such features with the in situ

data sets collected on the cruises as related to whale observations.

Starting six weeks before and during each cruise, SSH fields are monitored by TAMU and CU

scientists for the location of the Loop Current, Loop Current Eddies, and any companion

cyclones that are in or near the target field area for each cruise. Participants in the cruises will be

kept informed as these features are tracked. The altimeter database will be used to estimate
75

where and when anticyclonic and cyclonic eddies over the continental slope affect the observed

physical and biological parameters measured in the study region. Also, the SSH database will be

used to monitor the Loop Current as was done for the MMS-supported DeSoto Canyon Eddy

Intrusion Study (Hamilton et al., 2000) to identify any possible intrusions into the far northern

Gulf.

4.5.2 Flow-through Temperature, Salinity, Fluorescence and Chlorophyll

Near-surface temperature, conductivity, and fluorescence are logged approximately every minute

during cruises on the R/V Gyre through its Serial ASCII Interface Loop (SAIL) system. Data

from the thermosalinograph-fluorometer are binned every 1 minute giving about 0.25 km

horizontal resolution of near-surface temperature, salinity, and fluorescence if the ship is

underway at cruising speed of 9 knots. The fluorometer is calibrated to give chlorophyll by at sea

filtration and analysis for chlorophyll of samples taken from the flow line concurrently with

recorded fluorescence. Every second or third day the inflow to the flow-through fluorometer was

shut down for 4-6 minutes, during which time the internal cuvette is bleached by the addition of

full-strength commercial chlorine bleach as a precaution against growth of algae by biofouling

on the quartz sides of the internal cuvette.

Temperature and conductivity are measured by Sea-Bird sensors in a sampling stream that is

pumped from a hull depth of about 3.5 m into the main laboratory through a debubbler and

mixing chamber of 20-liter volume. Because the pumped flow rate of the sampling stream was

20 l·min-1, the water in the mixing chamber has a residence time of about one minute. This

pumped flow is reduced from 20 l·min-1 to 1 l·min-1 using garden hoses connected by adjustable

ball valves to a "Y" splitter valve leading off the debubbler. This 1 l·min-1 flow is shunted to the

temperature and conductivity sensors and to a continuous-flow Turner Designs model 10

fluorometer in the main laboratory.

Raw fluorescence data are calibrated against extracted chlorophyll measured in 1-liter samples

drawn several times per day from the pumped sampling stream. Calibration follows standard

methods given by Parsons et al. (1985). For each cruise, separate algorithms are determined for

high and low chlorophyll regimes by regression of fluorescence data with extracted chlorophyll

data.

4.5.3 CTD Data

Continuous profiles versus pressure were made of temperature and conductivity using a Sea-Bird

SBE-19 SeaCat Profiler. Two CTDs instruments were taken on each cruise, with one serving as

back-up. Only the primary CTD was used on both cruises. The primary CTD was calibrated by

the manufacturer prior to the first cruise of the summer. The temperature sensor has a

measurement range of -5°C to +35°C, an accuracy of 0.01°C, and a resolution of 0.001°C . The

conductivity sensor has a measurement range of 0 to 7 S·m-1, an accuracy of 0.001 S·m-1, and a

resolution of 0.0001 S·m-1. As converted to depth, the pressure sensor has a range of 0 to 6000

m. The SeaCat was set to record internally. When recovered, the data are downloaded to a PC for

processing. Back up copies are made to CD-ROM or other electronic media.

The CTD data are processed through the CTD data acquisition software, SEASOFT Version 5.26

(see Sea-Bird Electronics, Inc., at http://www.seabird.com), to produce a clean set of 0.5-m, binaveraged data. The configuration files used in this processing contain the instrument calibration

values. The processing includes steps to:

1. Convert raw data to engineering units,

2. Separate the upcast from the downcast data,

3. Correct data for pressure reversals due to ship heave,
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4. Mark/remove wild data points,

5. Correct conductivity for thermal mass effects,

6. Low-pass filter the data,

7. Average data into 0.5-m depth bins, and

8. Compute potential temperature, salinity, sound speed, and potential density using

algorithms in Fofonoff and Millard (1983).

These steps constitute the primary QA/QC of the continuous data sets. After processing with

Sea-Bird software, the bin-averaged data for each station are stored electronically in files with

the Sea-Bird extension, ".cnv", in the name. Back-up copies are made and stored in the Data

Office.

In secondary QA/QC processing of continuous data, the *.cnv files are processed to check for

out-of-range data, density inversions, and gaps. The salinity, temperature, and sigma-theta are

checked to be sure the values fall within reasonable ranges. Depths are checked to make sure

they are monotonically descending. Individual station plots of the continuous sensor data are

prepared and inspected to identify spurious data points. Problems identified are corrected in the

*.cnv files by linear interpolation across gaps or by replacing bad data with "-999.00" or similar

bad data flag; a note on the correction is included in the file header. The latitude, longitude, date

and time (in UTC), and total water depth included in the header are checked and corrected as

necessary.

4.5.4 XBT Measurements

XBT profiles were obtained using Sippican, Inc., T-7 and T-10 probes. T-7s are nominally rated

to 760 m and T-10s to 200 m. However, T-10s recorded to the maximum depths of the wire, so

depths sometimes exceeded 200 m. XBTs were deployed from the electronics lab on the Gyre's

port side. The probes were released from a hand-held launcher into a tube that extends through

the floor and over the port rail, where they fell into the sea a distance of 1.5 m. The raw data files

were logged by a Sippican Mark-12 board inserted into one of the PC data loggers on board. A

plot of temperature versus depth was displayed in real-time. If the wire broke prematurely before

the probe reached its designated maximum depth or if the temperature versus depth signal

appeared anomalous for any reason, the operator interrupted data collection and launched

another XBT.

At the moment of deployment, the XBT operator produces an event marker in the GERGNAV

navigation computer. GERGNAV is a program created by the TAMU Geochemical and

Environmental Research Group (GERG) to collect differential GPS data and to interface these

data with Gyre operations. The event marker records the UTC time and differential GPS location

in a disk file at the time of the drop. On the paper copy of the XBT profile, the operator records

these values along with a bottom depth reading provided by bridge personnel and the

temperature and salinity from the flow-through system. This hand-written information provides a

cross-check against the digital data.

The binary format files are converted to ASCII using Sippican software. The ASCII files are

plotted and inspected by eye for reasonableness. The first three data points are discarded as they

show clear evidence that the probe has not yet either reached the water or come into equilibrium

with the sea temperature. Data collected after an active probe reaches the seafloor also are

removed. While this depth is frequently obvious from the temperature record, the corrected

fathometer depths are used to truncate the records when needed. Traces are examined for

outliers. Outliers are replaced by linear interpolation for gaps of a few points or with the flag

value -999.00 for larger gaps. Traces which are bad in their entirety are eliminated.
77

The depth of an XBT is determined by measuring the time elapsed since its release and

converting this time to depth using an empirically-determined drop rate equation. Several drop

rate equations exist. The older original equation provided by Sippican is useful for comparing

profiles from decades ago to recent profiles. For our work, we used the more accurate

formulation of Hanawa et al. (1995).

4.5.5 Acoustic Doppler Current Profiler Measurements

A 153-kHz narrow-band ADCP (S/N 355) and a 38-kHz ADCP (S/N 8) were used on both S-tag

and D-tag cruises on Gyre. These ADCPs were manufactured by RD Instruments, Inc. (RDI).

When on station, the nominal maximum penetration depth of the 153-kHz ADCP is

approximately 250 m (130 m while underway). The maximum depth, however, is a nominal

value based on typical oceanic backscatter. The actual range will vary depending on

environmental conditions, including sea temperature and ship speed. The 38-kHz ADCP will

provide information on currents and backscatter to depths of 500-800 m while underway at

cruising speeds of 9 knots. Both units were vessel-mounted directly onto the ship's hull.

Mounting and calibration of the 153-kHz ADCP aboard R/V Gyre is described in Murphy et al.

(1992). The 38-kHz ADCP was mounted using divers.

Navigation Data: Accurate ship position data are crucial for useful shipboard ADCP data.

Differential global positioning system (DGPS) position fixes are used and usually are available.

An AshTech ADU2 3DF positioning antenna array (S/N AD00251), installed on the R/V Gyre

and capable of providing accurate ship heading by utilizing DGPS fixes, was configured to

provide ship heading directly to the ADCPs. It is used to collect high-precision positioning

information that is fed to users through GERGNAV. The array provides more accurate attitude

(pitch, roll, heading) information than the ship's Sperry gyrocompass. Ship heading determined

using the Ashtech was saved in a separate file for post-cruise integration into the ADCP

processing. The Ashtech heading allows processing and QA/QC of data collected while onstation, accelerating/decelerating, and turning.

Standard ADCP Processing: ADCP data are recorded using the RDI data acquisition program,

VMDAS. VMDAS is an MS-Windows based program that allows for advanced averaging,

merging, and visualization schemes. It records binary ADCP data and converts the data to

engineering units. The configurations recorded for the ADCP and used by VMDAS for data

logging and processing are shown in Table 4.5.1. Configurations are basically identical for each

cruise. This enhances continuity among the different cruises and simplifies analysis and

interpretation. Ensemble processing was used on VMDAS-recorded data. It merged the ADCP

ensembles, consisting of 4-15 seconds of data, with the navigation data from the AshTech

antenna to produce current velocities. The velocities then are averaged to produce the fiveminute data, which are output in ASCII format. Also output into the ASCII data files are several

additional parameters including: date/time/location of observations, vertical and error velocities,

the percentage of good ping data, and acoustic echo intensity (in decibels) of each beam.

After collection and converting the averaged files to ASCII format, the QA/QC processing of the

resulting data continues on UNIX workstations using a combination of FORTRAN, PV-WAVE,

and GMT computer codes. The QA/QC processing of the ADCP data are complex and requires

several levels to merge navigation data, determine absolute ship velocity with respect to the

DGPS fixes, calculate current velocity, and remove outliers and suspicious data. The QA/QC

processing can be separated into four parts: (1) merging of navigation data, (2) rejection of data

due to external factors, (3) rejection due to internal factors, and (4) systematic visual examination

of vertical and horizontal plots of current velocity. The final step in the processing is the

production of ASCII data files containing the processed data and associated metadata and

horizontal, vertical, and gridded plots of the quality-controlled data.
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Table 4.5.1

ADCP configuration summary

Parameter 153-kHz 38-kHz

Instrument type narrow-band phased-array

Frequency (kHz) 153.6 38.4

Transducer pattern concave flat

Depth cell length (m) 4 16

Number of depth cells 75 80

Segment time (minutes) 5 5

Time between pings (sec) 1 3

First bin depth (m) 14 36

Transmit pulse length (m) 4 16

Blank after transmit (m) 4 16

Navigation type DGPS DGPS

Data recorded raw, navigation, raw, navigation,

Current velocity is estimated by subtracting ship speed from the 5-minute averaged ADCP

transducer velocities. Poor estimates of ship velocity will seriously degrade data quality.

Therefore, good, reliable DGPS data are crucial for a quality shipboard ADCP data set. Ship

velocity estimated by the ADCP bottom-tracking mode is used when good bottom track fixes are

available, usually in water depths of less than 300 m. Calculated DGPS ship velocity is used

when the ship is in deeper water, as was the case during most of the SWSS cruises. The subset of

data with both bottom-track and navigation velocities is used to perform a directional calibration

of the ADCP after the procedure of Joyce (1989). The errors are of two types: sensitivity and

alignment. Sensitivity errors arise because the orientation of the acoustic beam is not correct due

to factors such as nonzero trim to the transducer and ship, small errors in the beam geometry, or

over-all system bias. The alignment errors are caused by misalignment between the reference

frames of the ADCP and the navigation data. Joyce (1989) notes that these two types of errors

arise from independent sources and produce errors approximately orthogonal. The misalignment

induces an error in the velocity component perpendicular to the ship that is linearly related to the

ship speed, while the sensitivity errors occur in the ship-parallel component, again in linear

proportion to ship speed. The mean alignment error is typically one to two degrees for the R/V

Gyre, i.e., viewing the ship from above, the data are rotated clockwise by this angle. The mean

sensitivity error is typically 1.00 to 1.04, so the data are scaled up by this value. The complex

regression statistics for the bottom-track versus DGPS navigation velocities and the average

DGPS ship speed are summarized in Table 4.5.2.

In Table 4.5.2, bm is the regression modulus and is a measure of the gain or bias between the two

vector sets,  is the offset angle between the two data sets, and 2 is the coherence parameter,

which measures the amount of variance in the GPS-determined velocities accounted for by the

bottom-track-determined velocities (2 = 1.0 for perfect coherence). Table 4.5.2 shows the

regression modulus and angle fall within typical values for the sensitivity error and mean

alignment error of Gyre. Bender and Kelly (1997) also give a more detailed description of the

estimation of the regression angle, modulus, and coherence.
79

Table 4.5.2

Complex regression statistics for GPS velocity versus bottom-track velocity

Description S-tag 153-kHz D-tag 153-kHz D-tag 38-kHz

Number of stations for misalignment angle 4194 1487 890

Sample size actually used 9818 4226 7089

Clockwise regression angle () -0.67 -0.72 0.968

Regression modulus (bm) 1.00514 1.00989 0.999304

Coherence parameter (2) 0.996803 0.998949 0.999845

Average GPS ship speed (cm·s-1) 251.8 351.4 375.6

Note: There were no usable data from the 38-kHz ADCP during the S-tag cruise.

After the navigation data are merged with the ADCP data, the data are inspected for problems

external to the data. These external factors include:

1. No navigation data for a given ensemble,

2. Bottom track depth too shallow for any good data,

3. Slow ship speed (speed < 100 cm/s),

4. Fast ship speed (speed > 650 cm/s), and

5. The percent good pings for the first bin is less than 30%.

6. Insufficient number of beams to produce a velocity estimate.

Data not passing the stipulated requirements for each factor are rejected and removed from the

database. Those that pass are corrected as described below and reformatted into a more

manageable and efficient format. A summary of the results of this step is given in Table 4.5.3.

Further, the bottom 15% of the vertical profile is rejected as unreliable due to improper echo

return near bottom. Therefore, the deepest usable bin number is readjusted during this step of

processing. If the adjusted bottom depth is less than the first bin depth, the segment is discarded.

Processing software for this stage was composed largely in FORTRAN.

After data are removed from the ADCP database due to external reasons, the remaining data are

examined for internal problems. Internal data problems are intrinsic and mainly include outliers.

Outliers are determined using basic statistics and are identified by estimating the standard

deviation and mean of each velocity component for the entire cruise at a given depth level. The

entire segment is rejected when any velocity component at any depth is greater than three

standard deviations from the average value. This procedure removes many of the grossly

anomalous velocity vectors in the ADCP data. Velocity fields also are replaced by a no data flag,

"-999.99", if the percent good field falls below 30.

The above-described QA/QC processing steps mainly are objective and based on constraints of

the physical system. In the next processing step, vertical profiles showing along- and crosstransect velocities and horizontal maps at a given level are produced, analyzed, and inspected to

identify suspect and questionable data. Suspect data are evaluated and then are left as is, flagged

as suspect, or rejected entirely and replaced with the no data flag. Viewing such plots allows the

data to be examined in context and marks the beginning of the data analysis phase as processes

and features become evident. Note that this step is the most subjective and, therefore, the most

labor intensive, part of the QA/QC. By its nature, this step is considered to be fine tuning of the

dataset since all the gross outliers have been removed previously. Approximately 30-50

segments (out of order 2000) are removed during this step of post-processing. Most of the plots
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Table 4.5.3

Results of evaluation of 153 and 38 kHz ADCP data for external factors and number of data

segments rejected

Description S-tag 153-kHz D-tag 153-kHz D-tag 38-kHz

Total number of segments 5073 1755 1128

Segments rejected for no navigation 31 24 173

Segments rejected for bottom-track depth too shallow 4 16 28

Segments rejected for slow ship speed (< 100 cm·s-1) 470 124 37

Segments rejected for fast ship speed (> 650 cm·s-1) 000

Segments rejected for first bin % good less than 30 0 0 0

Segments rejected for insufficient beams 374 104 0

Total usable segments 4194 1487 890

produced during this stage of processing use the contouring, gridding, and mapping capabilities

of the Generic Mapping Tools (GMT) Software System (Wessel and Smith, 1995).

After all quality control steps are performed, the data are formatted into an ASCII data file for

distribution to MMS and NODC. The files include metadata with cruise identifiers, instrument

type, FORTRAN formatting instructions, and program contacts. In addition, special problems

and important processing information unique to the cruise are included in the metadata. This

information begins with "$SWSS VERSION" and represents a history of the processing done on

that file. The information is crucial to the proper interpretation of the data. It is recommended

that the user become familiar with all such information prior to analysis and interpretation.

Following the metadata are the data which are listed by ensemble with the date, latitude, and

longitude of the beginning and end of each ensemble followed by the GPS ship velocity and

bottom-track depth. The current velocity by depth is then reported with vertical and error

velocities, the signal intensity of each transducer, and the percent good pings. These latter

parameters remain virtually unchanged throughout the estimation of horizontal current velocity

and are useful as data quality indicators.

Ensemble Processing Procedure: To improve the overall data quality and to recover segment

data eliminated because of bad pings, special in-house processing software was developed during

the MMS-sponsored Northeastern Gulf of Mexico Chemical Oceanography and Hydrography

Study (Jochens and Nowlin, 1999). The Ashtech data are used for special processing of the

individual 8- to 10-second ensembles that are averaged together to make the 5-minute segments.

Ensembles are composed of four 2-second pings, of which two are used for bottom tracking,

which is good only over the shelf. The remaining two are averaged together to estimate current

velocity. In the original processing method, all ensembles are automatically averaged into 5-

minute segments for further processing by the VMDAS software. Our experience with shipboard

ADCP data, however, has shown that occasionally one or more ensembles in a segment have

unrealistic or bad values that result in the removal of an entire 5-minute averaged segment. By

quality controlling and discarding bad ensembles prior to averaging into 5-minute bins, the data

quality is substantially increased. The ensemble processing is computationally intensive and

therefore only used in special circumstances when the standard processing fails. The ensemble

processing procedure was not used on any data sets obtained during the summer 2002. However,

the procedure is available for use if needed on future cruises.
81

A by-product of the ensemble processing is the ability to quality control ADCP data when the

ship is on station. Previously, these data were discarded because of unreliable ship heading and

errors in the 5-minute data due to ship acceleration and deceleration when approaching and

leaving a station. The ensemble processing also will lead to removal of slow ship speed criterion

for excluding segments.

ADCP Data Quality: Data quality of the 150-kHz ADCP was good for both the S-tag and D-tag

cruises. The percent good data quality indicator showed 100 percent data return to about 165 m

depth. Data quality then fell to 50 percent good at about 220 m depth. Other data quality

indicators (vertical and error velocities and echo intensity) were within expected limits. In

general, the narrowband 150 kHz ADCP data were typical of data taken from previous cruises in

the northern Gulf of Mexico.

Data quality of the 38 kHz ADCP was poor. Data recorded during the S-tag cruise was unusually

noisy. Quality control parameters such as vertical and error velocities were outside acceptable

limits. We consider the S-tag 38 kHz data unusable. We believe that mechanical and electrical

problems caused the poor data quality during the S-tag cruise. These problems include: poor

acoustical insulation from ship engines, unintentional grounding of the ship’s electrical system,

malfunction of the ADCP deck box, and mechanical deterioration of the transducer frame

potting. After the S-tag cruise and prior to the D-tag cruise, many of the problems were identified

and corrected. These included: replacement of the deck box, rewiring of the ship’s electrical

systems, and improvements in acoustically isolating the transducer from ship engine noise. These

changes slightly improved the data quality of the 38 kHz ADCP during the D-tag cruise.

However, the maximum penetration depth of reliable data from the 38 kHz only reached about

250 m. Below this depth, the data were noisy and unrealistic. Above 250 meters appear

reasonable but should be considered suspect and only used with caution. The cause of the suspect

quality was attributed to the degeneration of the potting which seals the machine screws between

the transducer frame and the ceramic transducer. The instrument has been sent to RD

Instruments for refurbishment and will be available for use during the 2003 cruises.

4.6 Data Management

A data management plan was developed for SWSS on 30 July 2002. In brief, the scientists

provide their raw data to the Data Office after each cruise. This provides a remote back-up of

these data. After completion of QA/QC efforts, the scientists also provide their final data sets to

the Data Office for archival and back-up. Much of the final data will be provided to Federal data

repositories, MMS, and/or other organizations that hold data sets of the types collected in SWSS.

The data management plan is given below.

4.6.1 Introduction

The objectives of data management for the Sperm Whale Seismic Study (SWSS) are four-fold.

First is to prevent data loss by duplication and secure storage of data from collection through

archival. Second is to assure data quality control. Third is provide for archival of the data sets in

a central data repository and, as appropriate, in federal or other data centers. Fourth is to support

the scientific mission of the study by facilitating the dissemination and use of the data by the

program scientists and the MMS managers.

Three entities participate in the data management. They are:

1. the data originators, who collect the original ("raw") data, perform the quality

assurance/quality control (QA/QC) on their data sets, and provide the basic analyses and

interpretations of their data,
82

2. the central data repository, which will be at Texas A&M University, with Dr. Matthew K.

Howard as Data Manager, and

3. the data recipients, which include the program scientists, MMS for selected final data

sets, the National Oceanographic Data Center (NODC) for final physical oceanographic

data sets, and the North Atlantic and Mediterranean Sperm Whale (NAMSW) catalogue

for selected sperm whale fluke photographs.

The key program scientists and their respective institutions are:

• Doug Biggs, Matt Howard, Ann Jochens, Texas A&M University (TAMU)

• Dan Engelhaupt, University of Durham

• Jonathan Gordon, Ecologic

• Nathalie Jaquet, Bernd Würsig, Texas A&M University-Galveston (TAMUG)

• Bill Lang, Sarah Tsoflias, Minerals Management Service (MMS)

• Robert Leben, University of Colorado (CU)

• Bruce Mate, Oregon State University (OSU)

• Peter Tyack, Mark Johnson, Patrick Miller, Woods Hole Oceanographic Institution (WHOI)

The International Association of Geophysical Contractors (IAGC) also is a major participant in

the SWSS project by virtue of their contribution of a seismic source vessel for the D-tag

experiments. IAGC is represented by Chip Gill.

The types of data being collected during the S-tag cruises (S-tag) and D-tag cruises (D-tag) are:

1. locations of tagging or other sampling (all participants collecting data)

2. satellite tracking data (S-tag, OSU as data originator)

3. D-tag data (D-tag, WHOI as data originator)

4. acoustic data (S-tag, Ecologic and OSU as data originators; D-tag, WHOI as data

originator)

5. visual observations (S-tag, Ecologic, OSU, and TAMUG as data originators; D-tag,

WHOI as data originator)

6. photo-ID data (S-tag, Ecologic, OSU, and TAMUG as data originators; D-tag, WHOI and

TAMUG as data originators)

7. genetic analyses (S-tag and D-tag, Engelhaupt as data originator)

8. physical oceanographic data, including CTD, XBT, ADCP, flow-through temperature,

salinity, fluorescence, and calibrated chlorophyll (S-tag and D-tag, TAMU as data

originator)

9. satellite images of sea surface height (TAMU as image originator with data from CU)

10. structure locations and lease blocks (MMS as data originator)

11. seismic source data for the study and possible information on seismic vessel activity in

the Gulf of Mexico during the study period (arranged through IAGC).

4.6.2 Data Manager

Dr. Matthew Howard will be the Data Manager for this study. He holds both B.S. and Ph.D.

degrees in Oceanography and has been employed at Texas A&M University in the capacity of

data analyst and data manager since 1991. He was the principal Data Manager for the MMS

LATEX-A and MMS Deepwater Reanalysis Programs and is currently employed in that capacity

for the MMS NEGOM, MMS JETS programs, and for the physical oceanographic data sets

collected by the MMS DGoMB program. He is currently the Data Manager for the Texas

General Land Office's Coastal Modeling effort in charge of the acquisition, redistribution, and

archival of large (~3.2GB/day) continuous streams of weather observations and numerical

weather model output for the Gulf of Mexico. He also is involved in the National Ocean

Partnership Program (NOPP) Gulf of Mexico Region National Virtual Ocean Data System
83

(NVODS) with the responsibility of making the archive of Gulf of Mexico Physical

Oceanographic data sets available on demand via the Distributed Ocean Data System (DODS).

He is a participant in a Sea Grant-sponsored coastal hypoxia study charged with acquisition and

usage enhancement of all available dissolved oxygen data for Gulf of Mexico coastal waters.

Howard has extensive experience in the management of large archives of data and model output,

quality control and quality assurance of physical oceanographic data sets, acquisition of large

and small data sets, data archeology and rescue, production and incorporation of metadata and

adherence to Federal guidelines for metadata. He was in charge of the production of the nine

CD-ROMs coming out of the MMS LATEX, MMS NEGOM, and MMS Deepwater Programs.

He is experienced with data formats, database, 3-D visualization systems, interactive data

analysis systems, and is a member of the ESRI Marine GIS user group. He is familiar with the

MMS Coastal and Offshore Resource Information System (CORIS). He maintains close and

frequent contact with personnel at the User Services group of the National Ocean Data Center

and is intimately familiar with their holdings and data information access portals. He has kept

abreast of the activities of developing National Coastal Data Development Center and the

evolving Gulf of Mexico observing systems.

4.6.3 Data Back-up

The data originator will record pertinent information in data logs during collection of the data

sets. High quality copies of these logs will be made as back-ups and provided to the Data

Manager. Digital data will be copied to disks or CD-ROMs. Original data sets will be provided

to the Data Manager for archival in the central data repository at the SWSS Data Office located

at TAMU. This also provides an additional, offsite back-up for the original data. Original data

will be provided by the data originator in batches corresponding to reasonable sets of data, such

as one season's worth of satellite data or one cruise's worth of acoustic data. All original data will

be provided, including satellite tag data, D-tag data, acoustic data, visual observation data,

photographic data, and physical oceanographic data. The SWSS Data Office will not release or

distribute these data further except as requested by the data originator or MMS or as required by

law and then with approval of MMS and the knowledge of the data originator. As the data

originators work with their data, routine back-ups will be made.

Routine back-ups will be made by the data originator. Quarterly, the data originator will provide

information to the Program Manager on the progress of QA/QC efforts; the Program Manager

will summarize such progress in the Quarterly Reports to MMS. The final data sets will be

provided by the data originator to the Data Manager for archival at the SWSS Data Office and

for submittal as required by the Cooperative Agreement.

4.6.4 Data QA/QC and the Database

Each data originator is responsible for performing QA/QC processing on their data sets to assure

high data quality and to prevent loss of data. They will use standard, accepted procedures for

each specific data type. Final data sets are those for which all QA/QC processing has been

completed. Final data sets will be provided to the Data Manager near the end of the project, in

time for preparation for submittal of the data sets to MMS, NODC, and the NAMSW catalogue

concurrently with the draft of the final report.

4.6.5 Data Archiving Procedures

The central data repository for Study data sets will be at Texas A&M University. Both original

and final data files will be stored on a hard disk connected to the Data Manager's main computer.

The ownership and file protection bits of these files will be set so they cannot be deleted

inadvertently and no changes can be made to the file contents. The contents of all hard disks
84

attached to this system will be backed-up at regular intervals to 4mm DAT tape, CD-ROMs, or

other appropriate storage device. The contents of the back-up media are verified, and the back-up

media are stored offsite. As new data are acquired and as value is added to the existing data

through the quality-control and quality-assurance steps, new tapes and CD-ROMs will be created

and stored Per the Cooperative Agreement, data will be retained by the SWSS Data Office in

the archive for three years after the end of the study.

4.6.6 Data Usage and Sharing

Sharing Among Participants: OSU will provide S-tag data to the participants on the D-tag cruise

to guide them to whales. The Data Manager will assist with this effort if requested by OSU.

Additional data exchanges between participants will be undertaken by the data originators to

facilitate preparation of required reports and/or publications.

Sharing with MMS: Selected final data, discussed in Section G below, will be provided by the

Program Manager to MMS concurrently with submittal of the draft synthesis report as required

by the Cooperative Agreement. If MMS requests data during the course of the project, the data

will be marked provisional prior to transfer.

Sharing with IAGC (Industry): IAGC will work with the SWSS Program Manager to set up a

data sharing agreement that will allow the SWSS Data Office to accept and store proprietary data

on shot locations, dates, and times in the Gulf of Mexico from cooperating industry parties. It is

anticipated that the first and last shot points for each line, together with the date and time, will be

provided in a common format. Data will be provided in digital format to the Program Manager or

Data Manager. Data will be stored on CD-ROMs or other media and will be held confidential.

Data sets will be disseminated by the Data Manager only to academic, IAGC, or MMS persons

participating in SWSS and only with the approval or on the request of the IAGC/industry party

that originally provided the data set.

IAGC will engage in data exchanges with academic and MMS participants. Such exchanges will

be undertaken by the data originators, not the SWSS Data Office. However, the SWSS Data

Office will assist with such exchanges if requested by the data originators.

Sharing with Third Parties: The SWSS Data Office will not release or distribute the data

provided to the central data repository except as requested by the data originator or MMS or as

required by law and then with approval of MMS and the knowledge of the data originator. Data

requests received from third parties will be forwarded to the data originator, except as requested

by MMS. The data originators are limited in their sharing of data with third parties only by the

terms of the Cooperative Agreement in their subcontracts.

For data transfers from the SWSS Data Office, the Data Manager will be responsible for any

reformatting needed and the data transfer. Transfers will be made by ftp delivery, website

pickup, tape, or CD-ROM.

4.6.7 Data Submission

As required by the Cooperative Agreement, final data will be submitted as follows:

1. Geo-referenced data will be prepared by the Data Manager, using inputs provided by the data

originators, in accordance with the specifications of Section V.2.A of the Cooperative

Agreement. A draft version will be submitted concurrently with the draft synthesis report. The

final version will be submitted concurrently with the final synthesis report. Submittals will be to

the MMS persons and in the quantities specified in the schedule given in Section VI.A of the

Cooperative Agreement.
85

2. Physical oceanographic data will be prepared by the Data Manager and submitted to the

NODC, in accordance with the negotiated NODC Data Archiving Agreement, concurrently with

submission of the draft synthesis report (see Sections V.2 S and T of the Cooperative

Agreement). NODC will be provided with a CD-ROM containing the physical oceanographic

data in ASCII format.

3. Physical oceanographic data will be prepared by the Data Manager and submitted to MMS

concurrently with submission of the draft synthesis report in accordance with the schedule

specified in Section VI.T of the Cooperative Agreement. MMS will be provided with CD-ROMs

containing the physical oceanographic data in ASCII format.

4. Final versions of the S-tag, D-tag, and acoustic data sets will be prepared by the Data Manager

and provided to MMS in ASCII and/or geo-referenced formats. Submittal will be made

concurrently with the submittal of the draft synthesis report.

5. A selection of final sperm whale fluke photographs, as determined by TAMUG/Ecologic and

WHOI, will be submitted to the North Atlantic and Mediterranean Sperm Whale catalogue.

Submittal will be made by TAMUG/Ecologic and WHOI scientists, with copies to the Program

Manager. The submittal may be in batches or at the end of the program at the discretion of

TAMUG/Ecologic and WHOI. However, the final submittal will be made no later than

concurrently with the submittal of the draft synthesis report. Although the full body of

photographs submitted to that catalogue are not required to be submitted to MMS, the Program

Manager will provide a letter to MMS recording the submittal.
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5 TECHNICAL SUMMARY

On 16-17 January 2003, the SWSS scientists, MMS managers, and other interested parties met in

New Orleans, LA, to discuss plans for the 2003 SWSS field program. Reviews of SWSS and

SWAMP preliminary results were given as background for that meeting and as part of the MMS

Information Transfer Meeting (ITM) on 15 January 2003. Given below are synopses of the

reviews from the ITM.

5.1 Sperm Whales in the Gulf of Mexico: Photo-identification, Photogrammetry,

Acoustic Analysis and Observations of Medium-scale Movements During SWSS 2002

Dr. Jonathan Gordon, Sea Mammal Research Unit, Gatty Marine Laboratory, University of Saint

Andrews, Saint Andrews, Fife, Scotland, UK

Dr. Nathalie Jaquet and Dr. Bernd Wursig, Texas A&M University-Galveston, 5007 Ave U,

Galveston, TX 77551 USA

Introduction

Our brief for this presentation was to provide a general introduction to the sperm whale and give

an overview of research activities carried out as part of the SWSS 2002 project using "standard"

non-invasive sperm whale research techniques such as photo-identification and acoustic

monitoring and photogrammetry.

Sperm Whales

Sperm whales must rank amongst the most impressive of any animals. Even within cetaceans

they are remarkable, differing in many respects from the other great whales. In a nutshell:

• They are the largest of the toothed whales. Males reach lengths of 20m while females

grow to 12m. • They are the most sexually dimorphic of cetaceans. At 44 tones a mature male is over 3

times the weight of a 13.5 ton mature female. • They are the most accomplished of mammalian divers. Dives of over an hour to depths

below 2,000m have been recorded. • Their massive heads, which can account for up to a third of the body length of the males,

is the largest sound-producing organ in the animal kingdom. Sperm whales are very

vocal, producing loud clicks for most the time they are underwater. Recent research by

Bertel Mohl and colleagues indicates that they produce the most powerful of animalmade sounds (>230 dB re 1μ Pa @ 1m) focused in narrow beam (Mohl et al., 2000). • They have the lowest rate of reproduction of any mammal. Females mature at about 9

years of age. Gestation takes about a year and a half and suckling continues for a few

years. Average calving intervals in stable populations are around 5 years. Calves may be

cared for communally, and the oldest females may contribute to calf care and may have a

leadership role when they cease reproducing. Sperm whale populations were decimated

by pre-industrial and industrial whaling and have been very slow to recover. • They have the most highly developed social organization of any of the great whales.

Females and their young live together in stable family groups of between 12 and 30

individuals.

• They are extremely wide ranging. Sperm whales are found in deep waters in all of the

oceans of the world. Uniquely, although females and their young are confined to tropical

and temperate waters, mature males spend most of their time in cold temperate waters

ranging right up to the ice edge.

• They are very ecologically successful exploiting populations of deep-living fish and

squid about which we still know little. Before whaling, sperm whales were thought to
88

have been numerous, consuming more biomass than the world's entire modern fishing

fleet. • Perhaps most intriguingly of all, sperm whales have the largest brains that have ever

existed.

Sperm Whales in the Gulf of Mexico

Sperm whales are the most common species of large whale in the Gulf of Mexico. Extensive

surveys conducted during the GulfCet I and GulfCet II Programs (1992-1998) in the offshore

waters (100-2,000 m deep) of the northern Gulf showed that most sperm whales were

concentrated around the 1000-m depth contour south of the Mississippi River Delta (Davis et al.,

2000; Baumgartner et al., 2001). The Texas-Louisiana shelf has been a focus of activity for the

offshore oil industry over the past 30 years, with over 15,000 rigs operating in the area. As

inshore resources have become fully utilized and deep sea drilling technology has developed, oil

exploration beyond the continental shelf has become feasible and is increasingly commonplace.

Oil industry activities, including seismic surveys and increased levels of ship traffic, are now

impacting offshore areas that are believed to be critical sperm whale habitat.

Underwater noise, including that from seismic exploration, sonar and shipping, has been shown

to impact cetacean species. A number of observations have indicated that sperm whales are

highly acoustically sensitive and are easily disturbed by unusual sounds. For example, sperm

whales showed dramatic responses to military sonar signals in the Caribbean (Watkins et al.,

1985), and in New Zealand their vocal behavior changed when whale watching vessels were

present (Gordon et al., 1992).

There is little direct information on the effects of oil industry noise on sperm whales. Some

researchers have recorded quite dramatic responses: Mate et al. (1994) reported that sperm

whales moved out of an area after seismic surveys began, while Bowles et al. (1994) found that

sperm whales stopped clicking in response to weak seismic pulses from a ship perhaps hundreds

of miles away. Others, in contrast, have not been able to document such substantial effects (e.g.,

Swift et al., 1999). A number of unique features of sperm whale biology may make them

particularly vulnerable to acoustic disturbance. They are highly acoustically-oriented animals

and are vocal for most of the time that they are underwater on their long and deep foraging dives

(Gordon et al., 1992; Jaquet et al., 2001). In addition to these vocalizations, which probably

serve for short and long range echolocation, they produce complex patterns of clicks, called

codas, which are used for communication. Their deep diving, complex social organization and

extended period of calf dependence also may contribute to a heightened vulnerability to

disturbance.

Research on Free Ranging Sperm Whales

Offshore distribution and deep diving habits of sperm whales made them one of the most

difficult of species to study in the field. Bill Watkins was an early pioneer who realized the

importance of using passive acoustics as a means of finding and following sperm whales

(Watkins and Moore, 1982). A comprehensive research approach, which involved passive

acoustics, photo-identification, and photogrammetry, was developed by Whitehead and

coworkers (Whitehead and Gordon, 1986; Leaper et al., 1992; Gordon, 1990, 1991; Arnbom,

1987). Crucial to the success of these studies was the use of modest motor-sailors as low cost,

non-disruptive, independent research platforms (Whitehead and Gordon, 1986). This approach

has been used by a variety of research groups in many parts of the world, including Sri Lanka,

Azores, Caribbean, Mediterranean, Canaries, Madeira, Canada, New Zealand, and Gulf of

California. Whitehead and his group have been particularly successful working around the

Galapagos where they have developed methods for investigating population size, social

organization, movements and cultural structure (e.g., Jaquet and Whitehead, 1996; Whitehead,

1990, 1994, 1998, 2001a, b ).
89

SWSS has incorporated many of these techniques into its core program, in particular the use of

acoustics to find and follow whales. However, the exciting new telemetry projects that have

become its main focus require a very substantial research vessel, which is not appropriate for the

"traditional" sperm whale research approach and little time has been available for this sort of

study. Nevertheless, during 2002, we were able to conduct photo-id and observational work from

a small RHIB as a secondary activity during the satellite tagging project. In addition, the process

of finding and tracking whales for tagging provides us with both passive acoustic data and

tracking information of sperm whale groups at a medium scale. Analysis of these data is at a

preliminary stage but we can provide an overview of data collected and some very preliminary

results.

Preliminary Results and Discussion

Photo-identification: Photo-identification images were taken from a small RHIB when

opportunities allowed in the course of satellite tagging, and the tagging team also collected some

images from the tagging vessel. Good quality images were compared with existing photographs

in the North Atlantic and Mediterranean Sperm Whale Catalogue (NAMSC). Most Gulf of

Mexico images within this collection come from the GulfCet and SWAMP projects. Forty-four

different individuals were identified from images collected during SWSS 2002 bringing the total

Gulf of Mexico catalogue to 93 different individuals. This remains a rather small collection for

such an important area, a result, no doubt, of the lack of dedicated photo-identification research

in the region.

In a situation like this where new images are being compared to a very large existing collection

(there are thousands of images in NAMSC), automated matching tools are extremely useful.

During SWSS 2002 we used and tested a prototype automated fluke matching program being

developed by Dutch Scientists (Eric Pauwels and Adri. Steenbeek) as part of the Europhlukes

project. No matches were found between our 44 individuals and the sperm whales identified in

the North Atlantic, Mediterranean or Caribbean Sea.

Distribution: Figure 5.1.1 shows the distribution of sperm whales during the S-tag cruise of

2002. For each day, only the first identification of each individual was plotted on the map,

avoiding bias due to multiple sightings of the same individual. Most sightings were concentrated

just south of the Mississippi River Delta. This is consistent with previous studies in the Gulf of

Mexico (for example GulfCet).

Figures 5.1.2 and 5.1.3 show the effort expended, respectively, for visual and acoustic surveys

during the 2002 S-tag cruise. Due to unfavorable wind and weather conditions, only very limited

efforts were made to conduct visual surveys west of 90°W (Figure 5.1.2). Most of this effort was

done in winds of 12 knots or more ( Beaufort scale 4), and thus visual detection of sperm

whales was impeded by white cups. Compare, however, the acoustic survey effort in the west,

which was not impeded by these limitations (Figure 5.1.3). This emphasizes the importance of

using passive acoustics to survey for sperm whales. The search effort was very unequal along the

survey track (compare Figures 5.1.2 and 5.1.3). Most of the search effort was concentrated

between 91°W and 88°W, partly explaining the highest abundance of sperm whales found in

this area (Figure 5.1.1).

Mark Recapture Population Estimate: Mark recapture analysis using photo-identification

images can provide estimates of population size; indeed, the best current estimates of whale

population sizes have been made in this way. Although the existing data are still rather sparse for

such an analysis at this stage, we have used them to calculate a simple Peterson estimate for the

population. This indicates a population size of 298 with 95% confidence intervals of 137 and

890. Low sample sizes mean that this is very imprecise. It is in general agreement with, though a

little lower than, the population sizes indicated by visual surveys.
90

Figure 5.1.1 Distribution of sperm whales during the S-tag cruise in 2002. Each symbol

represents the location of the fluke-up of one identified individual. Different

colors and symbols were used for each day. For purposes of independence, only

the first sighting of an individual was plotted each day.

Defining what is meant by the term "population" is a knotty problem in any cetacean survey.

Often populations are determined according to management divisions rather than any biological

relevance. It is interesting to note therefore that mark recapture studies conducted within an area

of human influence, such as this one, provide an estimate of a "population" which is very

relevant to management. In this case photo-id will provide an estimate of the number of animals

that pass through the study area (and might thus be subjected to human activities) over the course

of the field seasons.

Habitat Use and Site Fidelity: In spite of the low sample size, nine matches were found between

the 44 individuals identified during SWSS 2002 and the existing Gulf of Mexico catalogue of 58

individuals from the period 1994-2001. One whale was first identified in August 1994 and was

re-identified 8 years later only 6 nautical miles from where it was first observed. Another

individual was re-identified after 6 years only 3 nm from where it was first identified. The

average resighting distance after two years was 30 nm and after one year 26 nm (Table 5.1.1). In

general, the distance between resights was small suggesting a high site fidelity, as has previously

been noted by Weller et al. (2000). However, the near absence of effort away from the

Mississippi River Delta area may also be responsible for the small distances between resights.

Photogrammetry: It has been suggested that sperm whales in the Gulf are smaller than those in

other areas. This could be a cause for concern, but no measurements of length have been made.

-90 W -89 W -88 W -87 W

27 N

28 N

29 N

30 N

31 N

+

X

24 June

+

+

+

25 June

26 June

28 June

1 July

2 July

3 July

4 July

5 July

6 July

7 July

8 July
91

Figure 5.1.2 Visual survey effort during the S-tag cruise in 2002. As white-cups impede the

visual detection of sperm whales, the survey effort in conditions with winds less

than 12 knots are separated from the survey effort in conditions with winds above

12 knots. This is indicated by the Beaufort 4 scale noted above.

Photogrammetric techniques have been used in previous studies to measure sperm whales but

they require a vessel with a mast or specialised stereo-photogrammetry equipment. We have

been experimenting with simpler methods, compatible with conducting photo-ID from small

RHIBs. Laser range finding binoculars are used to measure the range to fluking whales, allowing

the fluke width to be easily calculated. Relationships between fluke widths and total lengths were

extracted from whaling data. Only eleven individuals have been measured so far, but these

preliminary data tend to support the contention that Gulf sperm whales are small. The accuracy

of this technique needs further testing before any conclusions can be drawn.

Population Structure: Most encounters with sperm whales were with groups of at least five

individuals, and up to 13 different whales were identified within a group. On two occasions (29

June and 4 July), single males were observed. However, no estimate of size could be made as

RHIB-2 did not get the opportunity to approach any of these males. First-year calves were

occasionally observed.

Small-scale Movements: It has been shown that patterns of small-scale movements of groups of

sperm whales are a good indicator of the amount of food available to them in a particular

location. Figure 5.1.4 shows one example of a group that we followed for 9 hours on 3 July

2002. During this time, the group traveled a total distance of 27.4 nm while the straight-line

distance was only 6.3 nm. The amount of zig-zag performed by the group suggests high food

94 W 92 W 90 W 88 W 86 W

26 N

28 N

30 N

Night time

Off effort

Visual survey, wind<4

Visual survey, wind>4

30 N

28 N

26 N

94 W 92 W 90 W 88 W 86 W
92

Figure 5.1.3 Acoustic survey effort on SWSS 2002 S-tag cruise. The pink track denotes the

acoustic survey following a determined track line while towing at least one

hydrophone array at speeds ranging from about 4 to 6 knots. Red denotes tracking

of sperm whales by trying to stay in acoustic contact with whales or trying to

reencounter a group of whales after losing it.

resources in the area which could explain the high site fidelity found south of the Mississippi

River Delta.

The small-scale movements of a lone male that was followed for 7 hours on 4 July 2002 are also

shown on Figure 5.1.4. In this case the small-scale movements are completely different and

typical of a lone male in tropical waters. This male traveled a total distance of 13.5 nm with an

average of 4 nm between fluke-ups. At 1800 hour, the male entered the periphery of a group of

females and codas could be heard on the hydrophones.

Tracking of Movements and Headings in Response to Seismic Sounds: During the 2002 field

season seismic airguns could be heard clearly at 52% of monitoring stations when the vessel was

within what seems to be the whale's preferred area (south of the Mississippi delta, between

longitudes 88 and 90°W). Airguns and sperm whales were heard at 16% of monitoring stations.

The visual observers that search for whales, spot animals and then guide the tagging boat to them

during tagging sessions, record the range and bearing to all sightings and also estimate the

animal's headings. In some cases range is also measured accurately using video techniques

(Gordon, 2001). These data could provide medium-scale data on animal's responses to seismic

surveys complimenting the very detailed data from D-tags and the longer-term data from S-tags.

The bearing to seismic pulses was measured using the Ishmael analysis program to compare

arrival time at the hydrophones in the main towed stereo array, and these were compared with

the net movements of the whale groups. At this stage there are no indications that whales move

94 W 92 W 90 W 88 W 86 W

26 N

28 N

30 N

Off effort Acoustic survey Tracking

30 N

28 N

26 N

94 W 92 W 90 W 88 W 86 W
93

Figure 5.1.4 Example of small-scale movements. Each symbol represents the location of the

fluke-up of one identified individual. Red: small-scale movement of a group of

female and immature sperm whales followed on 3 July 2002. Yellow: small-scale

movement of a lone medium size male sperm whale followed on 4 July 2002.

away from seismic sources. However, a better analysis could be conducted if the location and

activity of seismic vessels in the area was known rather than relying on acoustic localisation.

Coda Analysis: Codas are stereotyped patterns of clicks made by sperm whales in social

situations. There is growing evidence that coda repertoires vary between different regions and

between different social groupings. Indeed, an exciting new paper (Rendell and Whitehead, in

press) suggests that coda repertoires reflect broad-scale cultural clans within sperm whale

populations. The existence of such "cultural" population structure could have important

management consequences. Clans may differ in experience and in many learned behaviours, for

example in the way they respond to perturbations such as human activity. These indications of

"cultural" population structure compliment the insights on population structure that genetic

analysis can provide.

Again, we are at a preliminary stage of analysis but indications are that the coda repertoires of

Gulf of Mexico sperm whales are quite different from those in the Azores and strikingly distinct

from codas recorded in the Windward Islands.

90.0 W 89.5 W 89.0 W 88.5 W

28.5 N

29.0 N

18h30

11h30

13.4 nm

9:00

18:00

6.2 nm
94

Table 5.1.1

Sperm whale resightings from SWSS 2002 S-tag cruise data

(The time between resightings is given in days (d) for matches in 2002 and in years (y) for

matches between SWSS 2002 and Gulf of Mexico catalogue of 58 individuals.)

No. of

individuals

sighted together

Date first sighted Date resighted Time between

resightings

Distance between

resightings (nm)

Matches within SWSS 2002

1 2 July 02 7 July 02 5 d 11.22

4 3 July 02 7 July 02 4 d 6.96

2 2 July 02 3 July 02 1 d 7.02

1 6 July 02 7 July 02 1 d 14.77

Matches between SWSS 2002 and Gulf of Mexico catalogue (58 Individuals)

1 23 Aug 94 3 July 02 8 y 5.6

1 26 Aug 96 3 July 02 6 y 2.8

2 19 July 00 3 July 02 2 y 22.0

1 30 June 00 6 July 02 2 y 9.4

1 15 July 00 3 July 02 2 y 67.0

1 28 July 01 2 July 02 1 y 18.8

2 18 August 01 6 July 02 1 y 30.0
95

5.2 Identifying the Seasonal Distribution of Sperm Whales in the Gulf of Mexico with

Satellite-Monitored Radio Tags

Dr. Bruce Mate, Oregon State University, Hatfield Marine Science Center, Newport, OR 97365

Background

Knowledge of the seasonal distribution of sperm whales has been limited to stranding data and

by the expense of logistics for recent aerial and vessel-based surveys (GulfCet and SWAMP).

These surveys identified a few "hot spots" of seasonally concentrated sperm whales in the

vicinity of the Mississippi Canyon and Delta region, as well as DeSoto Canyon. In 2001, a 10-

day cruise for tagging sperm whales was restricted by Tropical Storm Barry to just 3.5 days of

operation. Four tagging attempts resulted in one successful tagging, which operated for 137 days

before the batteries were exhausted. The tagged whale spent 95 days in the Northern Gulf—from

eastern Louisiana to western Florida—generally along the slope edge and roughly along the 900-

m depth contour. The whale then traversed the upper Gulf in 23 days, traveling at an average

speed of 3.7 km/h and an average distance of 191km from shore over waters up to 3,000m deep

(average = 1,677 m) to arrive in the Gulf of Campeche, Mexico, where 19 days of activity were

recorded before the tag's batteries were exhausted. Dive rates were highest during the high-speed

directed movements as the whale moved from the upper Gulf to Mexico.

Analysis of 2001 Tagging Data with Seismic Survey Data

An analysis was done on the movements of the 2001 S-tagged whale during the time a single

seismic vessel, the Polar Search, was active in the same general vicinity off the Mississippi

Delta (seismic vessel data courtesy of Phil Fontana, IAGC). Because of the tag's low duty-cycle

(4 h/d) and the polar orbiting nature of satellites carrying Argos receivers, we obtained an

average of only 1.7 locations per day. Thirty-four percent of all locations were of excellent

location quality (with location error of <150 m to 1,000 m). The whale’s locations were an

average of 46.7 km from seismic track lines (range 6.6 to 133.0 km), but these cannot be

interpreted as either tolerance or flight from seismic activities. On the large scale, it is obvious

that the whale did not leave the general Mississippi Delta region during the seismic surveys.

Using these same high quality locations, there was only a single day when two locations were

determined <30 km from the vessel track line but within 10 hours of each other. The locations

were 45 minutes apart and showed the whale moving from 3.4 to 6.6 km away from the vessel's

projected trackline at a speed of ~3.7 km/h. This single "sample" is too small to warrant any

serious attention.

2002 Studies

At its completion, the track of a single whale in 2001 constituted 95% of everything known

about the movements of individual sperm whales in the Gulf and became the model (expectation)

around which 2002 tagging studies were planned. Improvements in tag attachment techniques

and changing the tag's transmission schedule provided the opportunity for tags lasting up to one

year. Multiple duty cycles were incorporated to: 1) provide locations every third day for the first

55 days; 2) operate daily for 35 days (starting 5 days before the D-tag experiment); and 3) then

provide locations every fourth day to extend operation as far into the rest of the year as possible.

The cruise to apply satellite-monitored tags (S-tag cruise) ran from 19 June to 9 July 2002 aboard

the Texas A&M research vessel Gyre, starting from Galveston, Texas, and ending in Gulfport,

Mississippi. It included visual and acoustic survey efforts along a saw-tooth pattern, generally

centered along the 1,000-m contour, as well as photo-identification and behavioral studies once

whales were found. We did not see whales during the first 4 days due in part to poor weather.

When the weather improved, whales were not sighted consistently.

Eighteen sperm whales were tagged during the cruise between 24 June and 7 July (Table 5.2.1

and Figure 5.2.1). Location data were received from all of the tags. Because sperm whales rest at
96

Table 5.2.1

Date and location of S-tag deployments

Tagging # PTT # Date and Time Lat Lon Days Tracked*

1 5660 24-Jun-02 18:36 28.011 -89.913 63.7

2 5654 24-Jun-02 23:06 27.993 -89.913 122.6

3 5648 26-Jun-02 23:03 29.207 -87.178 75.0

4 5685 01-Jul-02 19:35 28.958 -88.109 252.8

5 5650 01-Jul-02 19:48 28.956 -88.109 249.3

6 5726 01-Jul-02 20:16 28.950 -88.113 248.8

7 5725 01-Jul-02 21:40 28.903 -88.099 248.8

8 5647 01-Jul-02 21:58 28.903 -88.092 135.7

9 5678 02-Jul-02 23:10 28.860 -88.529 17.1

10 5719 03-Jul-02 15:24 28.793 -88.808 70.7

11 5709 03-Jul-02 16:49 28.788 -88.764 247.0

12 5670 03-Jul-02 19:48 28.840 -88.692 243.4

13 5720 03-Jul-02 20:09 28.850 -88.673 30.8

14 5655 03-Jul-02 20:47 28.839 -88.687 74.6

15 5669 03-Jul-02 23:07 28.804 -88.693 243.3

16 5701 03-Jul-02 23:42 28.805 -88.698 247.2

17 5710 07-Jul-02 19:25 28.732 -88.923 82.4

18 5649 07-Jul-02 20:20 28.708 -88.911 246.2

* Some tagged whales are still transmitting. This information is updated to 11 March 2003.

the surface for prolonged periods (usually >10 minutes) after long dives (often > 40 minutes),

higher quality locations are achieved with this species than for any other large whale tracked by

satellite thus far. Only two tags were not deployed completely and these were the only tags to

last <60 days. At this writing, six months after tagging, eight tags are still operational. So far, the

18 whales have been tracked >47,000 km during 2,286 tag-tracking days and individuals have

moved >4,600 km. Figure 5.2.2 shows the distribution of the last location reported from each

tagged whale as of 31 December 2002. Tagged whales have ranged over most of the upper Gulf,

from Florida to the U.S./Mexico border with a strong preference for slope and canyon regions.

However, several individuals have gone offshore into waters more than 3,000 m deep. None of

the whales has yet gone into the Gulf of Campeche or left the Gulf of Mexico, begging the

question as to whether this contrast to last year's tagged whale is due to small sample size and

individual variability or year-to-year variation in the Gulf environment (possible El Niño effect).

Many interesting observations on social structure have been made, especially in relation to the

composition of pods, their geographic range and temporal stability, which may be unique to the

Gulf, but are not yet analyzed in sufficient detail to be reported here. Some interpretations of

these data will require the use of biopsy data that are not yet completed.

Continued analyses will include more detailed assessments of the type revealed here and

tendencies for whales to associate with temporal oceanographic features (SST from AVHRR,

chlorophyll concentrations from SeaWiFS, and fronts and cold and warm core rings identified

from TOPEX data). Analyses are ongoing and preliminary at the present time as the experiment

is still underway, so data should not be quoted without consulting the principle investigator.
97

90°W 89°W 88°W 87°W

28°N

29°N

1 2

3

645

78

9

1011

1213 14

1615

1718

50 km

Figure 5.2.1. Locations of S-tag deployments. Numbers indicate the successive tagging number

indicated in Table 5.2.1. Contour lines indicate the 200-m, 1000-m, 2000-m, and

3000-m isobaths.

Follow-up Observations

MMS approved funding for winter follow-up observations to determine possible adverse effects

of tags to whales, the social affiliates of tagged whales, and the behavior of tagged whales during

a period, when reproductive behavior might be expected. Logistics were originally planned for

follow-up observations in Mexico as the 2001 tagged whale had moved to the Campeche Gulf.

By late November, none of the 2002 tagged whales had moved into the Gulf of Campeche.

However, six of the tagged whales were within 50 km of the Mississippi River mouth, so winter

re-sighting field efforts were re-directed to that area. As of the ITM, a limited number of

attempts had been made to re-sight tagged whales. Several untagged whales had been sighted in

the area of locations reported for tagged whales. Subsequent to the ITM, two tagged whales with

tags still attached and one which had lost its tag were sighted. All three were judged to be in

good condition.

Planning for 2003 Field Work and Beyond

In planning for 2003, we considered three additional strategies that could be directed at the

seismic effects objectives of SWSS at a variety of spatial and temporal scales: 1) present Argos

tags can be programmed with a different duty cycle to achieve higher resolution (more locations

per day), but at the sacrifice of longer-term seasonal distribution data; 2) a depth-sensing S-tag

(presently under slow development because it is not funded) could describe the whale's use of the
98

Figure 5.2.2. S-tag deployment locations and last location determined from transmissions to 21

December 2002.

water column over a period of 4 months. These intermediate-duration tracks with summaries of

dive activities (depths, durations, surface times, percent of time in specific depth strata) would be

useful in estimating sperm whale exposure to seismic sounds. The technology is similar, but

smaller, to that used by Krutzikowsky and Mate (2000) in their bowhead whale study; 3) with

additional funding, a GPS-linked Argos tag can be developed for the 2004 field season, which

would provide one or more precise locations after every long dive (~36/d) for up to about 40

days. Such precision, resulting in directional vectors, could produce useful information for

evaluating the responses of whales to seismic surveys in either a controlled-exposure experiment

(CEE) or by analyzing seismic vessel operations, which happen to occur in the vicinity of tagged

whales. A CEE is the only way to assure that an adequate sample size of such circumstances

would be achieved for a definitive analysis of "immediate response".
99

After discussion of these options at the January 2003 Information Transfer Meeting, it was

decided that the S-tag project would continue to emphasize the development of seasonal

distribution information, but that supplemental budgets for the dive tag, further winter re-sighting

efforts in 2004, analyses of seismic vessel and tagged whales interactions, and GPS tag

developments will be supplied to MMS by SWSS management team so that they can chose what

route(s) they might wish to pursue.
100

5.3 Analysis of Sperm Whale Vocalizations from a Towed Passive Acoustic Array

Dr. Aaron Thode, Marine Physical Laboratory, Scripps Institution of Oceanography, La Jolla

CA 92093

The 2002 SWSS D-tag cruise on the R/V Gyre contained an onboard passive acoustics team,

comprised of Natascha Aguilar de Soto, Matt Grund, Aaron Thode, and Sarah Tsoflias. The

acoustics team had both short-term "tactical" and long-term scientific goals. The tactical goal

was to perform real-time monitoring and tracking of sperm-whale sounds, to guide the tagging

vessel to areas where tagging could be performed, starting at first daylight. Potential longer-term

scientific goals included (1) an analysis of the possible effects of the tagging boat on acoustic

contact times for individual whales, and (2) passive 3D acoustic tracking of the animals at close

ranges, either via combining acoustic tag data with towed array data, or by deploying two towed

arrays simultaneously. The tactical role was performed well, despite equipment failures and

limited tracking range due to poor acoustic propagation conditions. Some of the scientific goals

were also demonstrated to be achievable in principle.

Herein is contained a brief description of the acoustic system, an analysis of potential

correlations between acoustic contact times and presence of tag boat, and a proof-of-concept

demonstration of passive range-depth tracking using two arrays, for possible use in extending

analysis of tagging effects to baseline behavior.

Acoustic Equipment and Procedures

The acoustics team used two arrays: a three element "WHOI" array with ~150 m of cable

terminating in a tow-fish instrumented with a pressure/depth sensor, and a two-element

"Ecologic" array with 300 m cable. Both arrays had been previously used on the S-tag cruise. A

variety of software was used for the real-time tracking. The primary monitoring tool was

Rainbowclick, developed by Doug Gillespie at the International Fund for Animal Welfare

(IFAW). When fewer numbers of animals were present, or the acoustic contacts were faint, the

program Ishmael, developed by David Mellinger of Oregon State University, proved very useful.

In order to record notes and record signals to hard disk, the program Logger 2000 was used, also

written by Doug Gillespie of IFAW. Arrays were monitored 24 hours a day, and were deployed

during 20 of 25 days at sea. The only time when arrays were out of the water was during longdistance transits, when large distances needed to be covered.

A fundamental performance metric of an acoustic tracking system is the maximum range at

which signals of interest (e.g., sperm whales) can be detected above the background noise level.

Twice during the cruise experiments were performed to estimate the detection range of the

arrays. Results of two separate detection range tests suggested an effective detection range of

about 4 km at 4 knot tow speed for both arrays. Acoustic modeling of sound propagation in the

region using the normal mode code KRAKEN produced similar detection range estimates, and

suggested that deep sensors would have a detection range of around 10 km.

Analysis of Acoustic Contact Times

Tagging an animal is an intrusive process, and it remains unknown to what degree, if any, the

effect of either tagging or the attached tag has on fine-scale animal behavior. Ideally, detailed

visual and acoustic observations of a single "focal" animal should be made prior to tagging, but

establishing a long-term acoustic follow was difficult in the Gulf, due to the large number of

animals present at any given time, and the emphasis placed on placing tags as quickly as

possible. Instead, the acoustic team investigated two alternative approaches for statistically

measuring baseline dive behavior of untagged animals: statistical analysis of acoustic contact

times, and the use of three-dimensional passive acoustic tracking to measure descent rates and

maximum dive depths.
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Figure 5.3.1 shows computed distributions of all daylight acoustic contact times, considered here

as a proxy of animal dive times. Contact times have also been broken down into times where the

tagging boat was in or out of the water. The wide variance in acoustic contacts, particular the

large number of 10 minute and 2 hr+ contacts, is not an accurate measure of the true distribution

of animal dive times, for two reasons. First, during a large fraction of the daytime observations

the visual observations and tagging operations had control of the ship, so the passive acoustic

monitoring was not able to position the vessel to optimize acoustic tracking. As a result acoustic

bearings often merged, split, or faded away before the start or end of a dive could be ascertained,

biasing the data toward short dive times. Second, Thode made an early decision to focus most

monitoring effort during the day, with much more casual monitoring protocols during the

evening. In retrospect, this decision was probably a mistake, in that higher quality dive time

measurements could have been made in the night, when acoustics had control of the ship motion.

Despite these confounding factors, a distribution of dive times with a center moment between

30-40 min. is visible in the data. The problems with relatively small sample size are starkly

visible here in the form of wide histogram bin widths, so it appears that multiple years of data

would need to be collected to establish a sufficient sample size to make statistically significant

conclusions about potential tagging effects on animal dive time. That said, to within the

uncertainty caused by the small sample sizes, there seems to be no obvious difference caused by

the deployment of the tagging boat.

Passive Acoustic Range-Depth Tracking for Pre-exposure Studies

Passive acoustic three-dimensional localization of sperm whales provides another possible

approach for measuring baseline diving behavior, before exposure to tagging and/or seismic

operations. This approach, if successful, could yield behavioral parameters besides total dive

time that could be compared with data collected by the tag, including initial dive descent rate,

maximum dive depth, and location of an animal during certain acoustic events. In theory only

two hydrophones, deployed with a 100-200 m aperture, are needed to make range-depth

measurements, by exploiting surface echoes to create a virtual planar array. In order to obtain

azimuth a third hydrophone needs to be placed adjacent to one of the other two. The tracking

performance would be poor whenever the animals are broadside of the arrays, but much better

whenever the animals are directly ahead or behind the ship.

On 5 September 2002, both arrays were deployed to explore whether range-depth localizations

could be achieved with the array hardware. Four hours of data were collected for analysis, and

the best result over a fifteen minute period between 22:15 and 22:30 is shown in Figure 5.3.2.

The red and green tracks were obtained from whales forward of the ship, while the blue track

was derived from a whale broadside to the arrays, which yielded an unstable inversion, as is

apparent from the figure.

The computed whale depths in Figure 5.3.2, 200 and 300 m, are shallower than what one would

expect from standard sperm whale dives, but several tagged animals dove to similar depths

during a similar time period. More convincing, the descent rates of the animals obtained from the

depth subplot are 91 and 96 meters per minute, respectively. A tag deployed on an animal from

the same group the following morning (249a) had descent rates of 88 and 79 meters per minute

for the two dives recorded. Thus the passive acoustic trajectory estimates are consistent with tag

measurements, and the feasibility test seems successful. The key to the success of the technique

is a wide separation between the two arrays, and a quiet ship, so that the whales' baseline

behavior is not disturbed by platform noise. Both conditions were not quite met during the

present cruise, but if appropriate equipment is available in the future, passive three-D tracking

may provide additional pre-exposure data on the baseline behavior of tagged and untagged sperm

whales.
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Figure 5.3.1. Distribution of acoustic contact times, broken down into times measured with or

without a tagging workboat present in the water during daylight hours. The large

numbers of extremely short and extremely long dive times are artifacts of the

operational and logging protocols.
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Figure 5.3.2. Derived ranges and depths of three whales using a two-array passive acoustic

localization algorithm. The green and red trajectories are derived from whales

forward or behind the ship, while the blue trajectory was from a whale broadside

to the two arrays, a situation that makes the inversion unstable.
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5.4 Synopsis of Diving Behavior of D-tagged Sperm Whales

Dr. Patrick Miller, Dr. Peter Tyack and Dr. Mark Johnson, Woods Hole Oceanographic

Institution, Woods Hole, MA 02543

The Digital Acoustic Recording tag (D-tag) was developed to enable controlled exposure

experiments for deep divers. It was designed to

1. Track responses of marine mammals, especially deep divers, throughout their dives

2. Improve understanding of functions and costs of behaviors in order to infer biological

significance of behavioral disruption

3. Develop a dose:response technique to measure received level of stimulus at whale while

also measuring behavioral and physiological responses.

This presentation addresses points #1 and 2, while the presentation in Section 5.7 focuses on

point #3.

The scientific literature regarding the effects of airgun sounds on sperm whales is limited, and

largely consists of anecdotal observations suggesting that animals silence or move away from

survey vessels. Such naturalistic observations are potentially biased and provide little

information to understand the biological significance of observed reactions. Experimental

exposure of animals to carefully controlled sounds, while recording the response of the whale on

a state-of-the-art digital recording tag (D-tag), offers the potential to: 1) observe even subtle

responses by whales to noise; 2) evaluate the effect of the noise level on the likelihood of

disturbance; and 3) infer the biological significance of disturbance reactions.

In our 2003 ITM presentation, we combined findings from SWSS 2002 and previous sperm

whale tagging cruises to describe the diving behavior of sperm whales. During SWSS 2002, we

tagged a total of 19 sperm whales with the suction-cup attached D-tag, and recorded at least one

deep dive from 14 whales. On-animal recording time totaled 76 hours or more than 13 Gigabytes

of data recording animal movement and sounds heard and produced by the whale.

The rich acoustic data-set recorded by D-tag includes natural and man-made sounds including

seismics with received levels up to 143 dB re 1 μPa. Natural sounds include: codas, that often

lead to physical contact between whales; regular clicks, that produce audible echoes from the

sea-surface and sea-floor; and rapid-series clicks called "creaks" that appear to mark preycapture events. Echoes from the seafloor can be used to identify different foraging modes, "openwater" and "bottom" foraging. Previous work during SWAMP 2001 suggested that animals

might specialize in one foraging strategy. Bottom-foraging was exclusively observed in one

animal "Deep-Dan" tagged in DeSoto Canyon. The data from SWSS 2002, however, showed a

significant number of animals employing a mixed feeding strategy. These animals combined

open-water and bottom foraging in the same dive, suggesting flexibility in hunting techniques

and prey choice. We suggest that the whales make use of echoes to orient to the sea-bottom, and

also to the sea surface.

With the addition of 14 deep-diving animals recorded during SWSS 2002, we have found greater

diversity in swimming patterns during descent and ascent. The most common pattern is limited

gliding (<10%) during descent, and extensive gliding (>40%) during ascent. Certain whales,

however, made prolonged ascent glides of over 350m in length after steady fluking during

descent. Others glided extensively during descent, but fluked steadily on the ascent. Based on

our model of animal drag, air-buoyancy, and tissue buoyancy forces acting on gliding sperm

whales, we suggest these different fluking patterns result from differences in tissue buoyancy.

The most likely explanation is that these swimming patterns reflect differences in fat stores

carried by the tagged whales. Our model of forces acting on sperm whales is useful to explain
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these swimming behaviors and provides a quantitative index of the effort expended by animals to

forage at depth.

Data from SWSS 2002 also confirms our earlier finding that rapid-series "creaks" occur at outlier

points on the depth record during deep dives. Also, animal movement roughly doubles at the end

of creaks. This pattern of behavior supports the hypothesis that creaks mark the capture phase of

foraging. While every capture event may not be successful, creak-rates over whole dives are

likely to correlate with feeding by the whale. Thus, we propose to use creak-rates as a measure of

feeding disruption during controlled exposure experiments.

The SWSS 2002 data set is rich in social "coda" sounds, and the coda exchanges commonly

result in approach and physical contact between whales. We were able to conduct one successful

trial of a coda playback in SWSS 2002. The tag recorded the unfamiliar Mediterranean coda as

the whale ascended after a 40-minute dive. The tagged whale and other nearby whales produced

extensive codas during the subsequent surfacing. More replicates of these playbacks are needed

to experimentally explore how sperm whales use codas in communication and how noise might

affect this type of communication.

A significant breakthrough in SWSS 2002 was the first simultaneous tagging of multiple sperm

whales with D-tags. Our primary motivation for tagging multiple animals is to increase the

chance that a tag will stay on a whale for sufficient time to conduct a controlled-exposure

experiment (roughly 5 hours). Based on longevities of 40 tag deployments, 50% of tags that stay

on for an hour remain attached for 5 hours or more. Thus it is critical to attempt to tag multiple

animals prior to conducting a controlled exposure experiment.

Simultaneous tagging of multiple animals also has revealed a promising new technique to study

social coordination and communication in sperm whales. Measure of dive synchrony, underwater

spacing, and acoustic exchanges enable a much more powerful study of natural social behavior

in sperm whales. This knowledge will help us to understand the biological consequences of

disturbance by noise sources.
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5.5 Molecular Ecology of Sperm Whales (Physeter macrocephalus) in the Northern Gulf

of Mexico

Dan Engelhaupt, University of Durham, Dept. of Biological Sciences, Durham, England

Background

Several fundamental genetic related aspects for endangered sperm whales occurring in the

northern Gulf of Mexico were assessed during the 2000-2002 SWAMP and SWSS cruises. A

deeper understanding of the population structure and social structure of sperm whales using

genetic techniques is presently being integrated with a variety of ongoing research projects such

as digital acoustic recording tagging (D-tag), satellite-monitored radio tagging, distribution and

abundance estimates, habitat use patterns, and behavioral information to help establish realistic

conservation and management strategies for these whales. In addition to providing important

gender information for whales that have been satellite and D-tag tagged, our project provides

essential data on social and population structure required to fully assess the impacts that the oil

and gas industry and seismic exploration may or may not have on endangered sperm whales

occupying potentially critical habitat areas in the northern Gulf. Sperm whales are highly social

whales that occur in small clusters to large aggregations, in many cases, maintaining long-term

bonds between female group members. Their dependence on acoustic communication between

members and use of echolocation when feeding at depth make them vulnerable to anthropogenic

noise. Could an outside noise influence disturb the dynamics of the group, or on a much larger

scale, the population over time? The quantity and quality of knowledge gained from the

combination of genetic (via degrees of relatedness among associates), satellite-monitored radio

tagging, and behavioral studies provides the essential components to accurately describe social

structure on a detailed scale. The original designation of a single Gulf sperm whale stock that is

separate from the adjacent Atlantic and Caribbean is thought to be conservative. Stocks must be

defined using several parameters including genetics. Once stocks are defined, human-caused

disturbances or mortalities that occur to a stock can be managed appropriately. Such information

is vital for creating meaningful management strategies for these animals in general, and relative

to petroleum exploration and production in particular.

SWAMP and SWSS Cruise Sample Analyses

Tissue samples were collected during both SWAMP and SWSS cruises throughout 2000, 2001

and 2002. Overall, eighty-nine individuals (including satellite-tagged, D-tag tagged,

opportunistic, and stranded whales) were genotyped using both mtDNA and microsatellite

techniques. Gender was determined for nearly all of these samples using molecular sexing

techniques.

Population Structure and Male-Mediated Paternal Gene Flow: A comparative analysis of

matrilineal mtDNA and biparentally inherited nuclear genetic markers (microsatellites) have

begun to show population structure for female lineages, which is expected given previous

findings on social and reproductive behavior in this species. Nuclear DNA variation across

oceans appears non-significant suggesting males disperse and spread their genes to the more sitefaithful females. Of particular interest are four individuals located within three separate

geographic regions (the Gulf of Mexico (N=2), Mediterranean Sea (N=1), and the North Sea

(N=1)) that appear to be paternally related at the level of half-siblings. This trans-oceanic

paternal gene flow concept provides genetic evidence that sexually mature males may be ranging

over 12,000 km to breed with females from multiple geographic populations.

Group Structure: Members of 'groups' were predominately females, although some groups

appeared to contain only males, suggesting that bachelor groups may reside in the Gulf. During

the 2002 SWSS cruise, multiple members from two groups of whales (Group 3 and 5) were

tagged with satellite transmitters and subsequently biopsy sampled for genetic analyses.

Relatedness levels for each satellite-tagged group (and groups in general) suggest that the overall
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group is often unrelated, although groups did contain related whales. Analyses of mtDNA

showed that groups are comprised of both single and multiple matrilines, which combined with

the relatedness levels, may provide additional evidence to the idea of 'constant companions and

casual acquaintances' among sperm whale groups.

Future Goals for 2003

Genetic techniques supply a powerful set of detailed data that can be directly integrated with

both the movements of satellite tagged whales and the dive profile data of D-tagged whales. The

gender of a tagged whale may prove crucial to better our understanding of movement patterns

and dive profile data (i.e., do males and females react differently to anthropogenic noise

influences?). Simple modifications are underway to provide a skin sample from all whales

tagged with D-tags which will significantly increase our dataset with very minimal additional

effort or cost. Future work will continue to build on previous year's population and social

structure results by incorporating biopsy sampling with both satellite-tagging and opportunistic

sampling of whales, particularly focusing on whales of sexually mature size. This population has

already been subjected to many years of human activity and there is likely to be major oil-related

activity offshore here for many years to come. Social organization is an important component for

sperm whale survival yet seems vulnerable to disruption by disturbance. Understanding sperm

whale social organization in this putative population before it is exposed to any more

disturbance, and exploring whether it is affected by offshore activity is thus a priority. To

increase the resolution for population structure and trans-oceanic gene flow analyses, we

recommend sampling sperm whales located in additional geographic areas. A continuation of the

genetic components previously described will maintain both the quality and quantity of

information required for management purposes.
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5.6 Ship and Satellite Studies of Sperm Whale Habitat

Dr. Douglas C. Biggs, Dr. Matthew K. Howard, Dr. Ann E. Jochens, Dr. Steven F. DiMarco,

Department of Oceanography, Texas A&M University, College Station TX 77843

Dr. Robert R. Leben, Colorado Center for Astrodynamics Research, University of Colorado,

Boulder CO 80309

Dr. Chuanmin Hu, College of Marine Science, University of South Florida, St Petersburg FL

33701

To characterize the physical and biological environmental patterns where sperm whales were

encountered along the continental margin of the northern Gulf of Mexico in summer 2002,

hydrographic data from two cruises of R/V Gyre were combined with remote sensing of sea

surface height (SSH) using the TOPEX/POSEIDON and ERS-2 satellite altimeters and of ocean

color mapped by the SeaWiFS satellite. Texas A&M University oceanographers are responsible

for the hydrographic data collection and for the overall program management that is in place

among the several universities that are cooperating on the Sperm Whale Seismic Study (SWSS).

We collected a standard suite of oceanographic data, and also measured in vivo chlorophyll

fluorescence to estimate phytoplankton standing stocks. Our co-authors from the University of

Colorado and the University of South Florida provided weekly averages of sea surface height

and ocean color from January 2002 through September 2002 and daily satellite fields for the

June-July and August-September SWSS fieldwork periods when R/V Gyre was at sea. In this

summary, we first provide some background on the remote sensing measurements, circulation

features in the northern Gulf of Mexico, and factors influencing the biological productivity, and

then we discuss the data collected and some preliminary results.

Satellite altimeters are radars that measure the satellite height above the ocean. Because the

satellite orbit is known with high precision, these radar measurements are used to calculate the

fine structure of the sea surface. Thus, how high or low a particular region is relative to longterm average sea surface height can be determined. These sea surface heights, in turn, provide

information on the currents and circulation. Variations in ocean color, which in deepwater come

mostly from chlorophyll-containing plant (phyto) plankton, give information about the time rate

of change of food stocks at the base of the oceanic food chain.

The Loop Current is a main driving force for circulation in the deepwater Gulf of Mexico. This

current enters the semi-enclosed Gulf basin through the Yucatan Channel, turns anticyclonically,

and exits through the Straits of Florida. This energetic current episodically sheds large warmcore anticyclonic eddies that are 200-400 km in diameter. When they interact with the

continental margin, these anticyclones may spin down, shed filaments to form smaller-scale

warm slope eddies, or shed counter-rotating cold slope eddies. As they interact with the

continental margin, the anticyclones can spin up cyclones. The cyclones can be distinguished

from the anticyclones by measuring the depth of their 15°C isotherm. In cyclones, this isotherm

domes upward and nutrient-rich mid-depth water is domed close to the surface. This nutrient-rich

water has been shown to increase primary productivity in the mixed layer and to support

increased zooplankton and micronekton biomass, making the interiors of cyclones biological

"oases". In contrast, surface water downwells in anticyclones, so the interior regions are nutrientpoor biological "deserts".

SWSS Leg One: R/V Gyre cruise 02G08 (SWSS Leg One) surveyed for sperm whales along the

middle continental slope of the north central Gulf of Mexico from 94.7°W to 86.4°W. The cruise

departed Galveston, TX, on 19 June 2002, and concluded in Gulfport, MS, on 9 July 2002. From

20 June through 8 July, five CTD stations were made, thirty-five T7 XBTs were dropped to

profile temperature in the upper 760 m, and seven supplemental drops were made with T10

XBTs to collect additional data from the upper 200 m (Figure 3.1.1). Ocean current velocity was

logged every five minutes from two hull-mounted acoustic Doppler current profilers (ADCPs).
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Near-surface water was pumped from the ship's hull depth of 3.5 m through SeaBird temperature

and conductivity sensors and a Turner Designs Model 10 fluorometer to log surface temperature,

salinity, and chlorophyll fluorescence once per minute. Although the ship track was centered on

water depths of 900-1000 m, the SWSS Leg One survey generally followed a zig-zag course

between water depths from 575-820 m (zigs upslope) to 1125-1430 m (zags downslope).

During daylight, when the whales were visible to visual observers, they were seen mostly in 7

locations, as groups of 5 to more than 13 animals (Figure 3.1.2). These groups were not

encountered randomly in time or space, but instead most were heard or seen when the ship was

between 89.9°W and 87.1°W. Most of the contacts with whales were in water depths of 900-

1000 m, although some whales were heard or seen in water depths both shallower (to 700 m) and

deeper (to 1300 m).

At the start of Leg One, there was a gradient of increasing SSH from north to south along most

of the margin (Figure 3.1.5). Because water flows downhill, the SSH indicated that the currents

would flow mostly west to east, or southwest to northeast. Thus, currents would run along

margin or from off-margin to on-margin.

The first week of Leg One, Gyre surveyed between 94.75°W to 88°W. This survey confirmed

flow was along margin or on-margin almost everywhere from 94°W to 90°W. The second week,

Gyre worked east from 90°W to the eastern side of DeSoto Canyon, and also made a quick run to

Gulfport. The survey again found flow was mostly on-margin, except at one location just east of

89°W where Mississippi River outflow was encountered out on the 1000-m isobath, and another

near 87°W where off-margin confluence flow set up along the eastern side of the clockwisecirculating warm slope eddy over DeSoto Canyon. The third week, whales were studied from

88°W back towards Mississippi Canyon before the cruise ended in Gulfport on 9 July.

The ADCP record shows that currents generally ran directly on to or along the margin, tracking

anticyclonically around the northern edge of the warm-slope eddy seen in the SSH field between

92-89°W (Figure 5.6.1). Although the Leg One cruise track did not extend south far enough to

reach the center of that warm slope eddy, the 15°C depths were documented by XBT drops to be

more than 270 m at the deeper (southernmost) zags downslope from the 1000-m isobath. The

15°C depths confirms the ship penetrated into the northern edge of the warm slope eddy with

15°C depths > 250 m.

Our colleagues at Oregon State University are determining the frequency with which whales they

radio tagged in the northern part of the warm slope eddy ranged seaward from the 900-1000 m

isobath into eddy interior, and into the deepwater regions of cyclonic circulation to the east and

southeast of this anticyclone. Most places where whales were seen in June and July were high

salinity blue water rather than low salinity green water environments. Specifically, surface

salinity was generally > 36 between 94°W and 89°W, and in most of the region from 89°W to

86.5°W surface salinity was generally > 34.

Along-track in vivo fluorescence indicated there were only in 3 places along the mid-slope that

were biological 'hot spots' of chlorophyll > 1 μg/L documented locally. Figure 5.6.2 shows the

property-property relationship of in vivo fluorescence (left-hand y-axis) as a function of salinity

(x-axis). The corresponding chlorophyll concentrations are shown on the right hand y-axis. The

first order, straight line relationship indicates that the higher chlorophyll in low salinity water,

which originates inshore and gets transported out to the 1000-m isobath, is simply diluted when

it mixed with the more saline oceanic water. This straight-line relationship is typical of the

classical, conservative mixing diagram. Simply put, there is no further biological production

when this low salinity water gets transported offshore; the chlorophyll it contains is merely

diluted.
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Figure 5.6.1. Caterpillar plot of currents, measured during 2002 SWSS Leg One by the ship's

153-kHz ADCP, superimposed on the composite map of sea surface height

anomaly (cm) for 3 July 2003. SSH was determined from remote sensing by

altimeters in earth orbit for the ten day period 24 June – 3 July 2002.

In contrast, biological hot spots show up as deviations from the straight-line mixing line. They

show more chlorophyll than would be predicted from simple mixing alone. Near 89°W, where

Mississippi River water was encountered out on the 1000-m isobath, this water contained far

more chlorophyll than the "typical" margin water. Note though, that this Mississippi River water

shows no further biological production when it is transported offshore; the high chlorophyll it

contains also is merely diluted with oceanic water.

At two other locations, near 88°W and 87°W, there also was enhanced biological production. In

these locations, there is more chlorophyll than would be predicted on the basis of simple dilution

mixing of shelf water with oceanic water. These are locations in which "new" nutrients must

have been introduced to stimulate local growth of additional chlorophyll in deep water.

The three "hot spots" of locally high chlorophyll along the 1000-m isobath thus mark locations

of nutrient addition. At 89°W the source is the Mississippi River. At 88°W and 87°W the source

is apparently the "new" nutrients being mixed upwards by locally enhanced vertical mixing along

salinity fronts, tidal fronts, or other high shear environments. We stress, though, that such "hot

spots" of locally high chlorophyll were the exception, rather than the rule, during Leg One. In

contrast, hot spots of chlorophyll > 1 μg/L were the rule rather than the exception for Leg Two.
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Figure 5.6.2. Property-property plot of in vivo fluorescence versus salinity for SWSS 2002 Leg

One, S-tag cruise. Note the fluorescence in "hot spots" of anomalously high

chlorophyll plots above the straight line mixing curve.

SWSS Leg Two: R/V Gyre cruise 02G11 (SWSS Leg Two) departed Galveston, TX, on 20

August 2002 and returned to Galveston again on 16 September 2002. Eight CTD stations were

made and thirty-eight T7 XBTs were dropped to profile temperature in the upper 760 m (Figure

3.2.14). For most of the cruise the ship worked a geographically limited area of the middle

continental slope between 90°W and 88°W, in and around the Mississippi Canyon to the head of

DeSoto Canyon (Figure 3.2.1). Water was again pumped to temperature, salinity, and

chlorophyll fluorescence sensors in the main lab, but during Leg Two the ship's ADCPs were run

only during transits into and away from the principal operations areas.

During Leg Two, low salinity green water was found along a much greater area of the middle

continental slope than on Leg One. Only west of 91°W, where salinity was generally > 32, are

property-property plots of in vivo chlorophyll fluorescence versus salinity generally similar to the

straight-line dilution curves typical of Leg One (Figures 5.6.3 and 5.6.4). All that changes east of

91°W. From 26 August on, property-property plots show multiple sources of high-chlorophyll

water. Property-property plots of in vivo chlorophyll fluorescence versus salinity were mostly

non-linear, with "hot spots" of chlorophyll > 1 μg/L along the middle continental slope in a wide

range of surface salinity (27-34). These surface hot spots occurred over water depths of 700 m to

1000 m throughout most of the region from 91°W to 88°W, as "new" deepwater primary

production was enhanced in salinity fronts. Most of the sperm whales seen during Leg Two were

in green water environments. In these green water environments, more than two animals at a

time were frequently heard by the acoustics team.

SWSS Leg 1: in vivo Fluorescence v Salinity

100

200

300

400

500

600

700

800

900

1000

27 28 29 30 31 32 33 34 35 36 37

SWSS Leg 1: In vivo fluorescence versus Salinity

89W

88W

87W

4

3

2

1

0

CHL
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Figure 5.6.3. Property-property plot of in vivo fluorescence versus salinity for SWSS 2002 Leg

Two during 22 August through 2 September 2002. Note that fluorescence is

above the straight-line mixing curve for most of the data collected after 26 August

(east of 89°W).

The range of physical processes that create and maintain such surface hot spots of chlorophyll in

the Gulf of Mexico are becoming better understood (Walsh et al., 1989; Muller-Karger et al., 1991; Wiseman and Sturges, 1999; Biggs and Ressler, 2001). However, because sperm whales

eat squid and they forage for squid at depth rather than at the surface, it is unlikely these apex

carnivores respond immediately or directly to surface salinity, surface chlorophyll, or other

surface conditions. Thus, encounters with sperm whales may show only limited correlation with

"snapshot" surface conditions during individual cruises. On the other hand, sperm whales do

appear to aggregate in deepwater areas of the Gulf of Mexico where time-averaged planktonic

productivity has been greater than usual for time-scales of weeks to months (Biggs et al., 2000).

Finding the location of such areas, which may be spatially variable while being temporally

persistent, is best accomplished by remote sensing using a combination of altimetry and ocean

color.

The SSH anomaly data show a gradient of increasing SSH from north to south (from shelf to

slope) over most of the north central Gulf of Mexico for most of the first four months of 2002.

This is evident in animations of the near-real-time data as a temporally persistent although

spatially variable region of negative-to-positive sea surface height anomaly. In the negative SSH

part of this gradient, which usually includes the 800-m to 1000-m isobaths, the doming of

nutrient-rich mid-water close to the surface favors enhanced planktonic new production along

plot Fluor v Salin for 22-25 August

100

200

300

400

500

600

700

800

900

1000

26 27 28 29 30 31 32 33 34 35 36 37

SWSS Leg 2: in vivo Fluorescence versus Salinity

31 Aug - 2 Sep (88oW - 89oW)

26-29 August (89o

W - 87.5oW)

22-25 August (west of 89oW)

4

3

2

1

0

CHL
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Figure 5.6.4. Property-property plot of in vivo fluorescence versus salinity for SWSS 2002 Leg

Two during 3-15 September 2002. Note that fluorescence is above the straightline mixing curve for most of the data collected east of 88.5°W.

this continental margin. In March 2002, the Loop Current shed a Loop Current Eddy (LCE) and

in April 2002, this LCE in turn shed a warm filament that extended north into the DeSoto

Canyon. By May 2002, this warm filament had consolidated into a warm slope eddy (WSE), the

inshore edge of which reached the Mississippi Canyon region south of the Mississippi River

delta. The SeaWiFS ocean color imagery shows that the anticyclonic circulation around this

WSE pulled green water offshore into the eastern part of the SWSS field area, and that by late

May to early June 2002, this off-margin flow was best developed east of 88°W.

By mid-June, the gradient of increasing SSH over the slope from 94°W to 88°W indicates west

to east flow along most of the 1000-m isobath, but off margin flow west of 94°W and east of

88°W. Leg One XBT, CTD, and ADCP data confirmed that off-margin flow was present in both

of these areas. However, subsequent SSH altimetry maps indicate that what on Leg One had

been large-scale anticyclonic circulation in deepwater south of 27°N had between early July and

mid August 2002 broken up into several much smaller anticyclonic eddies. By mid-August, these

minor eddies were distributed pretty much all along the continental margin of the north central

Gulf. By combining altimetry with ocean color, it can be seen that a pair of WSEs south of

Mississippi Canyon and in DeSoto Canyon were entraining green water from the shelf and

transporting this off margin (e.g., see Figures 3.2.17 and 3.2.18).

plot Fluor v Salin for 3-7 September

100

200

300

400

500

600

700

800

900

1000

26 27 28 29 30 31 32 33 34 35 36 37

SWSS Leg 2: in vivo Fluorescence versus Salinity (continued)

9-12 Sept (88.5oW - 89.5oW)

3-7 Sept (88.3oW - 89.6oW)

12-15 Sept (west of 88.5oW) 4

3

2

1

0

CHL
114

SWSS Leg Two confirmed that off-margin flow of low salinity green water was present in most

of the region from 90°W to 88°W and also documented locally high chlorophyll in a "bulls-eye"

of high ocean color visible in SeaWiFS imagery in deepwater southeast of Mississippi Canyon

(Figure 3.2.19). The radio-tag location data that were reported by Dr. Bruce Mate in the morning

session of the 15 January ITM 2003 showed that one of the sperm whales he tagged during Leg

One had moved out into this deepwater hot spot of chlorophyll by August and that it stayed in or

near this hot spot for 2-3 weeks. However, most of the other radio-tagged whales remained either

in the green water between 91°W to 88°W along the 1000-m isobath or ranged west to the Texas

continental margin.

Summary: Cyclonic and anticyclonic eddies contribute biological and physical heterogeneity

along the continental margin of the northern Gulf of Mexico. Temporal and spatial variations in

the geometry of the eddy field along the 800- to 1000-m isobaths determine whether low salinity

green water flows off margin or high salinity blue water flows on margin. Green water is

biologically rich and will support more food for the squid upon which sperm whales prey.

Locally high chlorophyll also can develop when or where nutrient-rich water domes upward in

cyclonic eddies. Cyclonic eddies and other nutrient-rich features that persist for 3-4 months in

time may be important feeding grounds for sperm whales along the Gulf of Mexico continental

slope.

[Note: TAMU and CCAR support came from MMS-TAMU cooperative agreement 1435-01-02-

CA-85186. USF support came from OCS studies 98-0060, 99-0051, and 99-0054, and from

NASA contracts NAS5-97128 and NAG5-10738. SeaWiFS data are the property of Orbimage

Corporation and data use here is in accordance with the SeaWiFS Research Data Use Terms and

Conditions Agreement of the SeaWiFS project.]
115

5.7 Tracking Responses of Sperm Whales to Experimental Exposures of Airguns

Dr. Peter Tyack, Dr. Mark Johnson, and Dr. Patrick Miller, Woods Hole Oceanographic

Institution, Woods Hole, MA 02543

This section picks up after Section 5.4 that summarized information on the Digital Acoustic

Recording tag, which was developed to enable controlled exposure experiments for deep divers.

To review, the D-tag was designed to

1. Track responses of marine mammals, especially deep divers, throughout their dives

2. Improve understanding of functions and costs of behaviors in order to infer biological

significance of behavioral disruption

3. Develop dose:response technique to measure received level of stimulus at whale

while also measuring behavioral and physiological responses

The SWAMP cruises demonstrated our ability to track details of behavior of tagged deep divers.

We focus here on item #2 to select specific measures for behavioral disruption. These are

• Avoidance

• Evaluation of energetic costs and benefits of foraging dives -- critical for 

growth

– Benefit of dive: successful foraging runs

– Cost of dive: Measure drag, calculate work done by flukebeats

• Social disruption: response to coda contact, masking of codas

During the SWSS cruise, we were able to conduct two controlled exposure experiments to study

the responses of tagged sperm whales to sounds of an airgun array.

Figure 5.7.1 shows a map of the first experiment on 10 September 2002. The red dots on the

Gyre track mark the location of the ship when visual observers spotted the tagged whale at the

location of the red dots to the left of the Gyre track. The next surfacing is marked with blue dots,

and the third with green. The track of the source vessel is indicated on the lower left, with colors

indicating the number of airguns that were firing.

The tag was able to record the sounds of these airgun signals, and this showed different spectra

for airgun pulses recorded at different depths. As seen in Figure 5.7.2, the airgun signature from

the shallow, 20-m depth has much stronger high frequency components than the same airgun

array recorded at a depth of 600 m. We developed a MATLAB tool to estimate the received level

of these pulses. Figure 5.7.3 shows the received level analysis for an airgun impulse recorded at

600 m depth and 10 nautical miles from the array. This pulse was logged as having a received

level of 143 decibels.

The primary analysis we conducted to test for responses of this sperm whale to these airgun

pulses was to tally the rate of creaks, which the Section 5.4 presentation describes as a proxy for

feeding events. Thus, creak rates should indicate foraging success of the tagged whale. Figure

5.7.4 shows the dive pattern of this whale, along with creak rates, before, during, and after

exposure to the airgun impulses. During the pre-exposure dive, the whale made 10.6 creaks/hour,

during exposure, 16.4 and during the post exposure interval, 13.7.

The second controlled exposure experiment was conducted on 11 September 2002 with three

whales each of which was simultaneously carrying a D-tag. These whales were so close together

that the map plotting their movements shows just one track. In Figure 5.7.5, the source vessel is

indicated in the upper left, the Gyre track is indicated by the long black line, and the pseudotrack

of the tagged whales is indicated by the colored line starting to the left, crossing, and then
116

Figure 5.7.1. Track of vessels and sound transmission levels for the controlled exposure

experiment conducted on 10 September 2002.

finishing to the right of the Gyre track. The seismic vessel more or less paralleled the tagged

whales. Its closest point of approach was 4.5 nautical miles, at which time the whales were

exposed to a maximum received level of 148 dB. There is no indication that the whales showed

horizontal avoidance of the seismic vessel. Figure 5.7.6 shows the dive profiles and creak rates

of all three tagged whales during this experiment. We can summarize the variation in creak rates

before, during, and after exposure as shown in Figure 5.7.7. If we compare the difference in

creak rates before versus during exposure to 143-148 dB, there is no indication of a change in

creak rate (see Figure 5.7.8). However, this apparent lack of reaction comes with the caveat that

it represents a small sample size, especially when one considers that the three whales tagged at

the same time may not represent independent samples. This presentation should be taken as an

example with pilot data of our experimental approach. The top priority for the next field season

will be to increase the sample size, especially at higher exposure levels.

For sw253, minimum range from

source to whale was 10nm

Source

Vessel

Gyre

Track
117

Figure 5.7.2. Example of spectra for airgun pulses from CEE conducted 10 September 2002.

Figure 5.7.3. Received level analysis for airgun impulse. Recording was at the 600-m depth and

10 nm from the airgun array.

20 meter depth 600 meter depth
118

Figure 5.7.4. Dive pattern of sperm whale tagged for CEE conducted on 10 September 2002.

Figure 5.7.5. Tracks of vessels, airgun transmission levels, and whale movements during

controlled exposure experiment conducted 11 September 2002. The source vessel

is indicated by the line coded by transmission level on the left, the Gyre by the

long black line mainly in the middle; and the three tagged whales by the

pseudotrack mostly on the right.

10.6 16.4 13.7 creaks/hr

EXPOSURE

Whale depth (m)

3D

Pseudotrack

of whales
119

Figure 5.7.6. Dive profiles and creak rates for the three whales tagged for the CEE on 11

September 2002.

Figure 5.7.7. Creak rates before (pre), during (exp), and after (post) exposure to airgun sounds

for the four tagged whales in the CEE conducted on 10-11 September 2002.

9.0 10.2 20.0 creaks/hr

10.0 9.7 17.8 creaks/hr

16.0 11.2 21.2 creaks/hr

EXPOSURE
120

Figure 5.7.8. Difference in creak rates before versus during exposure to 143-148 dB indicates

there is no change in creak rate.

+100%

+50%

no change

-50%

-100%

? ? ?

TOP PRIORITY FOR SWSS ’03 DTAG

CRUISE MUT BE TO EXPLORE REACTIONS

TO HIGHER EXPOSURE
121

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