OCS Study 

MMS 2004-067 

 

Sperm Whale Seismic Study 

in the Gulf of Mexico 

Annual Report: Year 2 

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 2004-067

Sperm Whale Seismic Study

in the Gulf of Mexico

Annual Report: Year 2

Authors

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

September 2004
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) 736-2619 or

1-800-200-GULF

CITATION

Suggested citation:

Jochens, A.E. and D.C. Biggs, editors. 2004. Sperm whale seismic study in the Gulf of Mexico;

Annual Report: Year 2. U.S. Dept. of the Interior, Minerals Management Service, Gulf of

Mexico OCS Region, New Orleans, LA. OCS Study MMS 2004-067. 167 pp.

ABOUT THE COVER

The cover art shows an example of different mark types that can be found on flukes of sperm

whales. The unique characteristics of individual flukes, including overall shape and different

mark types, allow the photographic identification of individual sperm whales. The degree of

fluke marking on a sperm whale may vary between areas depending on factors such as predation

levels. The presence or absence of two types of marks, holes and missing portions, as shown in

the figure, can be used to investigate differences in markings between the regions such as the

northern Gulf of Mexico, the Sea of Cortez, and the South East Pacific. [Photo taken by Nathalie

Jaquet for SWSS]
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, and 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 Ecologic1 Co-PI for Photo-ID and mesoscale survey

Matthew K. Howard TAMU Data Manager

Nathalie Jaquet TAMUG Co-PI for Photo-ID and mesoscale survey

Mark Johnson WHOI Co-PI for D-tag/CEE study

Robert L. Leben CU Co-PI for habitat characterization

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

Patrick Miller WHOI2 Co-PI for D-tag/CEE study

Joel Ortega-Ortiz OSU Co-PI for S-tag study

Aaron Thode SIO PI for 3-D Passive Acoustic Tracking study

Peter Tyack WHOI PI for D-tag/CEE study

Bernd Würsig TAMUG Co-PI for Photo-ID and mesoscale survey

For habitat characterization, Steve DiMarco, Amanda Olson, and John Wormuth of TAMU

contributed to the authorship of this report, as well as to processing/analysis of data sets. Leila

Belabbassi assisted with preparation of the report. Natacha Aguilar de Soto, Matt Grund, Valeria

Teloni, Maria Elena Quero, Amy Beier, and John Diebold (on the spar buoy) contributed to the

authorship of the D-tag/controlled exposure experiment (CEE) data collection section. 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 three SWSS cruises we extend our great appreciation for making

the 2003 field program a great success. In particular, thanks to the whale survey and habitat

characterization cruise science team: Ricardo Antunes (Whale Museum, Madeira, Portugal),

Steve Berkowitz (Coastal Carolina University, South Carolina), Doug Biggs (TAMU College

Station), Paul Clark (TAMU, College Station), Dan Engelhaupt (Durham University, UK), Mike

Fredericks (TAMU, College Station), Jonathan Gordon (Ecologic Ltd., UK), Thomas Gordon

(Vanishing Point, Plymouth, UK), Bill Green (TAMU, Galveston), Nathalie Jaquet (TAMU

Galveston), Erin LaBrecque (New Hampshire), Jamie McKee (SAIC, Shalimar, FL), Sonia

Mendes (Aberdeen University, UK), Andrey Mishonov (Moscow University for Geodesy &

Cartography, RU), Simon Mustoe (Applied Ecology Solutions, Pty Ltd., Melbourne, AU),

Amanda Olson (TAMU, College Station), Will Rayment (Otago University, Dunedin, NZ),

Christoph Richter (Queens University, Kingston, ONT, Canada), Mark Tasker (Joint Nature

Conservation Cttee, Aberdeen, UK), Sarah Tsoflias (MMS Environmental Sciences), Jonathan

Vallarta (Heriot-Watt University, Edinburgh, UK), Eddie Webb (TAMU, College Station), Trudi

Webster (New Zealand), R.J. Wilson (TAMU, College Station), and John Wormuth (TAMU

College Station).

Thanks to the D-tag/CEE science team assembled by WHOI for D-tag/CEE work aboard R/V

Maurice Ewing: Natacha Aguilar de Soto, Dee Allen, Amy Beier, Alessandro Bocconcelli, Irene 

1

 also at the University of St. Andrews, UK

2

 presently at the University of St. Andrews, UK
vi

Briga, Kara Buckstaff, Dan Engelhaupt (Durham Univ. UK), Matt Grund, Mark Johnson

(WHOI), Patrick Miller (U. of St. Andrews), Anna Nousek, Michela Podesta, Todd Pusser, Maria

Elena Quero, Sue Rocca, Kenneth Alex Shorter, Valeria Teloni, Suzanne Yin. Thanks also to the

LDEO staff on the Ewing: Emily Chapp, John Diebold, Ethan Gold, and Chris Leidhold.

Thanks to the D-tag/CEE science team on the M/V Kondor Explorer: Craig Douglas (SEAMAP

Inc.), Terry Ketler (IEN), Joal Newcomb (EARS buoy team, Naval Research Laboratory), Doug

Nowacek (WHOI), Carol Roden (MMS New Orleans), Sandy Sawyer (Fairfield Industries), Jim

Showalter (EARS buoy team, NRL), and Aaron Thode (SIO). Special thanks Terry Ketler (IEN)

for braving life aboard both the Ewing and Kondor in the interests of making a video for MMS.

Thanks to the S-tag cruise science team: Trent Apple (Texas), Marty Bohn (TAMU GERG), Dan

Engelhaupt (Durham University, UK), Willie Flemings (TAMU GERG), Bill Green (TAMU

Galveston), Ladd Irvine (OSU Newport), Ann Jochens (TAMU College Station), Terry Ketler

(IEN San Francisco), Anurag Kumar (OSU), Rhoni Lahn (OSU), Bill Lang (MMS New Orleans),

Dan Lewer (OSU Newport), Bruce Mate (OSU Newport), Mary Lou Mate (OSU Newport),

Bruce Miller (OSU), Elizabeth Mitchell (TAMU College Station), Tom Norris (SAIC), Laura

Opsommer (OSU), Joel Ortega-Ortiz (OSU Newport), Alicia Salazar (TAMU College Station),

Sarah Tsoflias (MMS New Orleans), Eddie Webb (TAMU College Station), Andrew Wigton

(ExxonMobil), Elizabeth Zele (OSU), and Elizabeth Zúñiga (OSU Newport).

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, Captain James E. O'Loughlin and the crew of the

Ewing, and to the Captain and crew of the Kondor Explorer 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. John Walpert of TAMU GERG for their assistance

with preparing the 38-kHz ADCP, and Mr. Tomas Follett of OSU for facilitating delivery of Stag whale location information to SWSS scientists during their cruises.

The use of a seismic source vessel, which was crucial for conducting the CEEs, would not have

been possible without the contribution of the seismic source and vessel, M/V Kondor Explorer by

the Industry Research Funders Coalition (IRFC), consisting of BP Corporation, ExxonMobil

Exploration Company, Shell Exploration & Production Company, ConocoPhillips, ChevronTexaco Exploration & Production Company, and the International Association of Geophysical

Contractors (IAGC) on behalf of its members. SWSS scientists extend thanks to Chip Gill and

Alastair Fenwick of IAGC, as well as all members of IRFC, for their enthusiastic work in

support of SWSS. On behalf of IAGC, we would like to thank Finn Arne Aas of Seabird

Management AS; Jeff Cleland, Phil Fontana, and Nicola Quinn of Veritas DGC; Robert Walker,

Richard Jenkins, and Hans-Peter Waldner of Petroleum Geo-Services; Mark Baisa of Thales

GeoSolutions, as well as their donation of the SkyFix DGPS; Ian Rogers of WesternGeco, as

well as the loan of a Fast Rescue Craft for the cruise.

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

appreciated, as is his participation on the S-tag cruise. 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. Alexander Shor of NSF for their contributions, both in

support of tag development and in supporting the use of the R/V Ewing in field year 2003.

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

administration of the project. We thank Stacie Arms of TAMUG, Carol Delancey of OSU,

Tracie Robertson and Martha Tackett of TAMRF, 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.......................................................................................................................... xiii

Acronyms............................................................................................................................... xv

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

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

1.2 Field Measurements........................................................................................ 1

1.3 Technical Summary ........................................................................................ 2

2. Introduction ............................................................................................................... 3

2.1 Program Participants....................................................................................... 3

2.2 Program Activities for Year 2.......................................................................... 4

2.3 Report Organization........................................................................................ 5

3. Data Collection Cruises.............................................................................................. 7

3.1 Whale Survey and Habitat Characterization Cruise 2003................................ 7

3.2 D-tag Cruise 2003 .......................................................................................... 34

3.3 S-tag Cruise 2003........................................................................................... 55

3.4 3-D Passive Acoustic Tracking During D-tag Cruise 2003 ............................ 78

4. Technical Summary .................................................................................................... 85

4.1 Status Report on Satellite-Monitored Radio Tag............................................. 85

4.2 Molecular Ecology of Sperm Whales (Physeter macrocephalus) in the

Northern Gulf of Mexico................................................................................ 86

4.3 Studies Report on SWSS Records with the Digital Sound Recording Tag..... 87

4.4 Sperm Whale Abundance, Habitat Use, and Aspects of Social Organization

in the Northern Gulf of Mexico...................................................................... 90

4.5 Tracking Sperm Whale (Physeter macrocephalus) Dive Profiles Using a

Towed Passive Acoustic Array........................................................................ 104

4.6 Habitat Characterization: Eddy Forced Variations in On-margin and Offmargin Summertime Circulation Along the 1000-m Isobath of the Northern

Gulf of Mexico, 2002-2003............................................................................ 109

4.7 Habitat Characterization: Upper-Ocean Current Observations During

Summer: 2002 and 2003 Central Slopes of the Northern Gulf of Mexico...... 131

4.8 Habitat Characterization: Midwater Trawling Program................................... 133

4.9 Habitat Characterization: 38-kHz ADCP Investigation of Deep Scattering

Layers............................................................................................................. 135

5. Literature Cited ........................................................................................................... 141

Appendix: D-tag/CEE Mitigation Protocol ............................................................................. 145
ix

LIST OF FIGURES

FIGURE PAGE

3.1.1. Ship track for SWSS 2003 WSHC cruise aboard R/V Gyre 31 May – 20 June

2003................................................................................................................... 8

3.1.2. Locations of visual sightings of sperm whales on the SWSS 2003 WSHC

cruise in May/June 2003 superimposed over the daytime cruise track ................ 10

3.1.3. Locations of CTD and XBT stations on SWSS 2003 WSHC cruise.................... 15

3.1.4. Locations of chlorophyll samples on the SWSS 2003 WSHC cruise................... 15

3.1.5. Visual sightings of toothed whales and delphiniids on the SWSS 2003 WSHC

cruise ................................................................................................................. 22

3.1.6. Acoustic detections of sperm whales on SWSS 2003 WSHC cruise

superimposed on the cruise track occupied while towing the hydrophone arrays 28

3.1.7. Locations of biopsy samples on SWSS 2003 WSHC cruise................................ 28

3.1.8. Locations of IKMT collections on SWSS 2003 WSHC cruise............................ 30

3.1.9. Histioteuthid squid and fang-tooth blackfish from IKMT collections near

94°W. ................................................................................................................ 32

3.1.10. Plot of backscatter intensity from the 38 kHz ADCP.......................................... 33

3.2.1. D-tag cruise track of R/V Maurice Ewing for SWSS 2003 and locations of

XBT drops. ........................................................................................................ 37

3.2.2. Locations of D-tag deployments and skin samples superimposed over the

cruise track ........................................................................................................ 44

3.2.3. Dimensions of the airgun array towed by the Kondor......................................... 45

3.2.4. Source vessel Kondor in relation to the observation vessel Ewing while the

Kondor airguns were active................................................................................ 45

3.2.5 Track of the Kondor and spar buoy during the calibration run on 15 June 2003.. 54

3.3.1. Cruise track for SWSS 2003 S-tag cruise, R/V Gyre 03G07, conducted 26 June

– 14 July 2003.................................................................................................... 57

3.3.2. Sea surface height fields for the period 26 June through 13 July 2003 during

the SWSS 2003 S-tag cruise............................................................................... 59

3.3.3. Locations of XBT and CTD stations, superimposed on the cruise track, taken

during SWSS 2003 S-tag cruise ......................................................................... 61

3.3.4. Potential temperature-salinity diagrams for the five CTD stations taken during

the SWSS 2003 S-tag cruise............................................................................... 62

3.3.5. Cruise track and locations of chlorophyll stations taken during the SWSS 2003

S-tag cruise ........................................................................................................ 64

3.3.6. SWSS 2003 S-tag cruise track with the track during the visual survey effort

superimposed..................................................................................................... 66

3.3.7. Cruise track line and locations of sightings of sperm whales recorded during

the SWSS 2003 S-tag cruise............................................................................... 67

3.3.8. Sightings of cetaceans, other than sperm whales, recorded during the SWSS

2003 S-tag cruise ............................................................................................... 69

3.3.9. Histogram of qualitative scores from acoustic listening periods.......................... 72

3.3.10. Acoustic contacts during the SWSS 2003 S-tag cruise ....................................... 73

3.3.11. Locations of the 15 successful tag attachments during the SWSS 2003 S-tag

cruise ................................................................................................................. 75

3.3.12. Locations of biopsy samples for whales tagged in 2003 and 2002 and of the

sloughed skin sample ......................................................................................... 77

3.4.1. Example of autonomous flash-memory recorder deployed from Kondor and

Ewing ................................................................................................................ 79

3.4.2. Flash memory recorder and depth logger attached at the end of a 100-m

polypro rope....................................................................................................... 79
x

LIST OF FIGURES

(continued)

FIGURE PAGE

3.4.3. Examples of data collected from autonomous recorder on June 18 ..................... 82

3.4.4. Plot of arrival angles detected on SEAMAP array, using elements 2 and 3 (11-

m spacing), between 11:30 AM and midnight CDT on 18 June 2003 ................. 83

4.4.1. The Gulf of Mexico with study area outlined ..................................................... 91

4.4.2. Survey track lines designed using the Distance Program and realized track

lines during SWSS 2003 WSHC cruise .............................................................. 92

4.4.3. Number of sperm whales photo-identified each year; data set used for

abundance estimates........................................................................................... 94

4.4.4. Mean resighting distances (in nm) for identified individuals over a time span

up to 9 years ...................................................................................................... 95

4.4.5. Small-scale movements of groups of sperm whales in different areas of the

northern Gulf of Mexico. ................................................................................... 96

4.4.6. Root-mean square displacements for 8 groups that were followed for 8 to 12

hours.................................................................................................................. 97

4.4.7. Estimated group sizes for groups that were followed >7 hours in June 2003....... 98

4.4.8. Example of 2 mark types used to investigate differences in markings between

regions............................................................................................................... 99

4.4.9. Length distribution for groups of female and immature sperm whales in the

northern Gulf of Mexico and in the Sea of Cortez .............................................. 102

4.4.10. Plot of photographic and acoustic body length measurements of Gulf of

Mexico sperm whales ........................................................................................ 103

4.5.1. Deployment geometry of towed passive acoustic range-depth tracking system... 105

4.5.2. A spectrogram display illustrating the measurements required for range-depth

tracking.............................................................................................................. 106

4.5.3. Example of automated estimates of relative arrival times of the surface echoes

relative to the direct paths and the relative arrival times of the sounds on two

different hydrophones using data from 19 June 2003.......................................... 107

4.5.4. Example of range-depth tracking even in the presence of hydrophone clipping. . 108

4.6.1. SSH field for 10 May 2002 ................................................................................ 110

4.6.2. Comparison of SSH conditions along the northern margin of the Gulf of

Mexico in May 2002 and May 2003................................................................... 111

4.6.3. Comparison of SSH conditions along the northern margin of the Gulf of

Mexico in June 2002 and June 2003................................................................... 112

4.6.4. Comparison of monthly composite SeaWiFS imagery and SSH conditions for

June 2002 and June 2003 ................................................................................... 113

4.6.5. Chlorophyll fluorescence versus salinity for June 2002 S-tag cruise on Gyre. .... 114

4.6.6. Comparison of monthly composite SeaWiFS imagery and SSH conditions for

June 2002 and October 2002.............................................................................. 115

4.6.7. Comparison of monthly composite SeaWiFS imagery and SSH conditions for

July 2002 and August 2002................................................................................ 116

4.6.8. Chlorophyll fluorescence versus salinity for September 2002 D-tag cruise on

Gyre................................................................................................................... 117

4.6.9. SSH conditions in May 2003, showing separation of LC Eddy "Sargassum." ..... 118

4.6.10. SeaWiFS composite for 18-24 May 2003, confirming separation of LC Eddy

"Sargassum." ..................................................................................................... 119

4.6.11. CTD profile from 11 June 2003 shows subsurface evidence for Subtropical

Underwater........................................................................................................ 120
xi

LIST OF FIGURES

(continued)

FIGURE PAGE

4.6.12. Relation of SSH to 15°C depths from XBT drops in early June 2003 ................. 121

4.6.13. Relation of SSH to 15°C depths from XBT drops in mid-June 2003................... 122

4.6.14. Synopsis of 15°C depths, determined during SWSS 2003 WSHC cruise on

Gyre, plotted versus longitude............................................................................ 123

4.6.15. Summary plot of location of XBT stations occupied by R/V Gyre and R/V

Ewing in June and July 2003, superimposed on SSH conditions for mid-June

2003................................................................................................................... 124

4.6.16. Sperm whale sightings superimposed on 15°C depth during SWSS 2003

WSHC cruise on Gyre........................................................................................ 125

4.6.17. At the northern edge of LCE "Sargassum," the SWSS 2003 WSHC cruise

encountered a sharp surface front on 16 June 2003............................................. 126

4.6.18. Chlorophyll fluorescence versus salinity on SWSS 2003 WSHC cruise on Gyre 127

4.6.19. Chlorophyll fluorescence versus salinity on SWSS 2003 S-tag cruise on Gyre ... 128

4.6.20. Relation of SSH to 15oC depths from XBT drops made on the July 2003 S-tag

cruise on Gyre.................................................................................................... 129

4.6.21. Comparison of monthly composite SeaWiFs imagery and SSH conditions for

June 2003 and April 2003 .................................................................................. 130

4.7.1. Sea surface height anomaly field for 11 June 2003 with currents at 41 m from

the 38-kHz ADCP superimposed ....................................................................... 132

4.8.1. The relationship between meters of wire out and depth of the trawl for five

tows representing different wind and current conditions..................................... 134

4.8.2. The volume filtered in the targeted depth interval as a percentage of the total

volume filtered for each trawl ............................................................................ 135

4.9.1. Relative backscatter counts shown for Gulf of Mexico slope region and for the

deep basin region ............................................................................................... 137

4.9.2. Relative backscatter counts recorded by the 38-kHz ADCP for the 100, 600,

and 700 m depth bins for the SWSS 2003 WSHC cruise .................................... 138
xiii

LIST OF TABLES

TABLE PAGE

3.0 Cruises Conducted in 2002 and 2003 for and Related to the Sperm Whale

Seismic Study .................................................................................................... 7

3.1.1 Science Personnel for SWSS 2003 WSHC Cruise Aboard the R/V Gyre............ 9

3.1.2 Summary of CTD Stations on SWSS 2003 WSHC Cruise.................................. 12

3.1.3 Summary of XBT Stations on SWSS 2003 WSHC Cruise.................................. 12

3.1.4 Chlorophyll Stations on SWSS 2003 WSHC Cruise........................................... 16

3.1.5 Synopsis of Nautical Miles and Hours of Effort Status....................................... 20

3.1.6 Nautical Miles and Hours of Effort for Each Effort Status by Sea State.............. 20

3.1.7 Locations of Sightings of Toothed Whales and Delphiniids on SWSS 2003

WSHC Cruise .................................................................................................... 21

3.1.8 Synopsis of Fluke-Out Sequences for Photo-ID.................................................. 24

3.1.9 Tissue Collection/Genetic Typing Samples Collected During SWSS 2003

WSHC Cruise .................................................................................................... 29

3.1.10 Summary of IKMT and MOCNESS Tows Taken on SWSS 2003 WSHC

Cruise ................................................................................................................ 31

3.2.1 The SWSS 2003 D-tag Cruise: D-tag/CEE Science Team on R/V Maurice

Ewing ................................................................................................................ 35

3.2.2 The SWSS 2003 D-tag Cruise: LDEO Science Team on R/V Maurice Ewing .... 35

3.2.3 The SWSS 2003 D-tag Cruise: Multi-Purpose Science Team on M/V Kondor

Explorer............................................................................................................. 36

3.2.4 Daily Summary of Tagging and CEE Activity During D-tag Cruise ................... 38

3.2.5 Location, Date, Time, and Depth of the 15°C Isotherm at XBT Stations ............ 41

3.2.6 Summary of D-tag Deployments for SWSS 2003............................................... 43

3.2.7 Summary of Visual Effort During SWSS 2003 D-tag Cruise.............................. 51

3.2.8 Tissue Collection/Genetic Typing Samples Collected During 2003 D-tag

Fieldwork .......................................................................................................... 52

3.3.1 Science Personnel for SWSS 2003 S-tag Cruise Aboard the R/V Gyre............... 56

3.3.2 Summary of Hydrographic Stations on SWSS 2003 S-tag Cruise....................... 60

3.3.3 Chlorophyll Stations for the SWSS 2003 S-tag Cruise........................................ 62

3.3.4 Visual Survey Effort by Day on the SWSS 2003 S-tag Cruise............................ 66

3.3.5 Sightings of Cetaceans Other Than Sperm Whales............................................. 67

3.3.6 Locations of Sightings of Cetaceans, Other Than Sperm Whales, Recorded

During the SWSS 2003 S-tag Cruise .................................................................. 68

3.3.7 Locations of Deployments of Sperm Whale Tags During SWSS 2003 S-tag

Cruise ................................................................................................................ 74

3.3.8 Tissue Collection/Genetic Typing Samples Collected During the SWSS 2003

S-tag Cruise ....................................................................................................... 76

4.4.1 Percentage of Individuals Having Holes and/or Missing Portions in Their

Flukes................................................................................................................ 100

4.4.2 Proportion of 1st Year Calves and Large Mature Males in the Northern Gulf of

Mexico Versus the Sea of Cortez ....................................................................... 101

4.8.1 Results of Z Tests of All Combinations of Displacement Volumes (DV) for

All Trawls.......................................................................................................... 134

4.9.1 Occurrence of Scattering Below the Main DSL (> 650 m) Out of the Number

of Possible Days in Water Less Than or Greater Than 1000 Meters for Each

Cruise While Over the Slope and Deep Basin..................................................... 136

4.9.2 Occurrence of Scattering Below the Main DSL (> 650 m) Out of the Number

of Possible Days When in Cyclonic, Anticyclonic, Boundary, or No Feature in

the Four Hydrographic Regions ......................................................................... 138
xv

ACRONYMS

ADCP Acoustic Doppler current profiler

AGU American Geophysical Union

AIM Acoustic Integration Model

CCAR Colorado Center for Astrodynamics Research, University of Colorado

CDT Central Daylight Time

CEE controlled exposure experiment

CHL chlorophyll

CMS Cetacean Monitoring System

CPA closest point of approach

CTD conductivity-temperature-depth sensor

CU University of Colorado

DGPS Differential Global Positioning System

DGoMB Deepwater Gulf of Mexico Benthic Habitats Program

DNA deoxyribose nucleic acid

DSL Deep Scattering Layer

D-tag Digital-recording acoustic tag (also DTAG)

DV displacement volume

EARS Environmental Acoustic Recording System

GERG Geochemical and Environmental Research Group at TAMU

GIS Geographical Information System

GPS Global Positioning System

GulfCet Gulf of Mexico Cetacean Study

IAGC International Association of Geophysical Contractors

IEN Interactive Educational Network

IFAW International Fund for Animal Welfare

IKMT Isaacs-Kidd Midwater Trawl

IMaRS Institute for Marine Remote Sensing

IPI inter pulse interval

IRFC Industry Research Funders Coalition

ITM Information Transfer Meeting

LC Loop Current

LCE Loop Current eddy

LDEO Lamont Dougherty Earth Observatory

MCS middle continental slope

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

MOCNESS Multiple Opening-Closing Net and Environmental Sampling System

MRC Mississippi River Canyon

MRD Mississippi River Delta

mtDNA mitochondrial DNA

M/V Marine Vessel

NASA National Aeronautics and Space Administration

NATO North Atlantic Treaty Organization

NMEA National Marine Electronic Association, standard protocol for GPS receivers 

to transmit data

NMFS National Marine Fisheries Service (now NOAA Fisheries)

NOAA National Oceanic and Atmospheric Administration

NRL Naval Research Laboratory

NSF National Science Foundation

ONR Office of Naval Research

OSU Oregon State University
xvi

ACRONYMS

(continued)

Photo-ID Photographic-Identification

PI Principal Investigator

PMEL Pacific Marine Environmental Laboratory

QA/QC quality assurance/quality control

RHIB Rigid-Hulled Inflatable Boat

RL Received Level

R/V research vessel

SAIC Science Applications International Corporation

SeaWiFS Sea-viewing Wide Field-of-view Sensor

SIO Scripps Institution of Oceanography

SRB Science Review Board

SSH Sea surface height

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

TDTR Time Depth and Temperature Recorder

UD University of Durham, UK

USF University of South Florida

UTC Universal Coordinated Time

VHF Very High Frequency

WHOI Woods Hole Oceanographic Institution

WSE Warm Slope Eddy

WSHC Sperm Whale Survey and Habitat Characterization

XBT expendable bathythermograph probe
1

1 EXECUTIVE SUMMARY

1.1 Introduction

This is the second annual report of the Sperm Whale Seismic Study (SWSS). SWSS is a multiinstitutional, interdisciplinary study supported by the Minerals Management Service (MMS) of

the U.S. Department of the Interior under Cooperative Agreement 1435-01-02-CA-85186 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 (UD), and Woods Hole Oceanographic Institution (WHOI) develop

and implement scientific research plans in coordination with MMS, the Office of Naval Research

(ONR), National Science Foundation (NSF), and Industry Research Funders Coalition (IRFC).

The principal study tasks and associated institutions are: Satellite-tracked radio tags (S-tags) by

OSU; Digital-recording acoustic tags (D-tags) and Controlled Exposure Experiments (CEEs) by

WHOI; Habitat characterization by TAMU; Photo-identification and mesoscale population

studies by Ecologic and TAMUG; Biopsy/genetic analyses by UD; 3-D passive acoustic tracking

by SIO; Program management by TAMU; and Data management by TAMU. Terry Ketler of

Interactive Educational Network (IEN) is preparing video documentation of the SWSS field

efforts during summer 2003. Additionally, a five-member Science Review Board (SRB) was

established in year 2 to provide review and comments on the draft Synthesis Report. The

program objectives and task goals are set out in the first annual report (Jochens and Biggs 2003).

1.2 Field Measurements

The 2003 field work consisted of two cruises in late May/early June 2003 and one cruise in

June/July 2003. Remote sensing images of sea surface height, ocean color, and sea surface

temperature were obtained before and during the cruises and provided to the interested scientists

on the ships. All activities associated with sperm whales were conducted pursuant to approved

permits from NOAA Fisheries (formerly the National Marine Fisheries Service or NMFS).

The D-tag/CEE cruise was conducted from the science vessel R/V Maurice Ewing working in

coordination with the seismic source vessel M/V Kondor Explorer. The D-tag/CEE cruise on the

Ewing departed Gulfport, MS, on 3 June and ended in Galveston, TX, on 24 June 2003. The

main area for the study was around the 1000-m isobath between 91° and 87°W in the northern

Gulf of Mexico. The Kondor rendezvoused with Ewing on 9 June and CEE work ended 22 June

2003. A stringent mitigation protocol was used to assure that no marine mammal or turtle would

be exposed to sound levels about 180 dB re 1 mPa RMS. A total of 11 D-tags were deployed for

80.5 hours of on-animal data collection; seven of the tags provided sloughed skin samples for use

in genetic analyses. Three CEEs were conducted with 2 tags out during one test and 1 tag out on

two others. An additional CEE with tags on two sperm whales was begun but then curtailed

during ramp-up due to mitigation. Both tags also detached shortly after the curtailment. Rough

weather and scarcity of whales resulted in seven lost days for CEE work. Preliminary estimates

of received levels during the CEEs ranged from 145-155 dB. Additionally, 376 hours of highquality sperm whale recordings were collected, 4,430 fixes were made on 810 different

surfacings of sperm whales, 13 high-quality photo-ID shots were taken, and 19 good-quality

XBT profiles were collected. Additionally, experimental passive acoustic monitoring was

conducted from Ewing and Kondor, video of the work efforts was taken, and, under a non-SWSS

project, airgun calibration tests were performed using an EARS buoy.
2

Concurrently with the D-tag cruise, a sperm whale survey and habitat characterization (WSHC)

cruise was conducted aboard the R/V Gyre. The WSHC cruise surveyed for sperm whales along

the middle continental slope of the northern Gulf of Mexico between 94.75°W and 86.75°W in

water depths ranging from 500 m to 1430 m. It departed Galveston, TX, on 30 May 2003 and

returned on 21 June 2003. Over 360 hours of acoustical monitoring with tandem two-hydrophone

arrays and over 200 hours of visual search with BigEye binoculars were completed. Photoidentification and photogrammetry, conducted from two rigid-hulled inflatable boats, resulted in

collection of 152 photo-ID sequences, with 79 different sperm whale individuals identified, of

which 57 were individuals not previously identified. Ten biopsy and three sloughed skin samples

were collected for genetic analyses. Near-surface water was pumped from 3.5 m to log surface

temperature, salinity, and fluorescence once per minute. Filtered water samples were analyzed

for chlorophyll to calibrate the fluorescence data. Ocean current velocity in the upper 300 m and

upper 900 m was monitored continuously with RD Instruments hull-mounted 153 kHz ADCP

and 38 kHz ADCP, respectively. To profile temperature in the upper 760 m, 89 XBTs were

dropped. Eight CTD casts were made to determine the temperature-salinity structure of the

water. Nighttime activities on the cruise included midwater trawling and plankton sampling.

Twenty-five oblique tows were made using an Isaacs-Kidd Midwater Trawl (IKMT) with mouth

opening of 14.7 m2. An 8-net collection with depth-stratified tows was made using a Multiple

Opening-Closing Net and Environmental Sensing System (MOCNESS) with mouth opening of 1

m2. The collections were rich in groups such as hatchet fishes, myctophids, viperfish, large

decapod crustaceans, and euphausiids. Small-size individuals of cephalopods also were present.

The S-tag cruise conducted from 26 June through 14 July 2003 aboard the R/V Gyre. The cruise

left Galveston, TX, but, due to Hurricane Claudette, ended earlier than planned in Pascagoula,

MS. Field work consisted of tagging sperm whales with satellite-tracked radio tags, associated

video work, photo-ID, and biopsy sampling. In addition to tagging activities, surveys for sperm

whales were conducted using visual observations and passive acoustics. Samples were collected

for habitat characterization. Videotape was taken for MMS use. Fifteen sperm whales were

tagged with S-tags and 15 biopsy/skin samples were obtained. In water depths > ~700 m, the

acoustic team monitored for vocalizing sperm whales for over 260 hours using tandem twohydrophone arrays. Visual observers searched the sea surface with BigEye binoculars for over

130 hours during daylight to locate sperm whales that were at the surface. Additionally, 5 CTD

stations were made, 48 XBTs provided profiles of temperature in the upper 760 m, and 75

samples were filtered and analyzed for chlorophyll content. Ocean current velocity in the upper

300 m and 900 m was monitored continuously with hull-mounted 153 kHz and 38 kHz ADCPs.

Near-surface water from the ship's hull depth of 3.5 m was pumped continuously to log surface

temperature, salinity, and chlorophyll fluorescence once per minute.

1.3 Technical Summary

On 19-21 November 2003, the SWSS Workshop and Planning Meeting was held at the Shell

Westhollow Technology Center in Houston, TX. Attendees came from the scientific community

(SWSS, EARS, AIM, airgun calibration, and other project scientists), the federal government

(including MMS, NSF, ONR, and NOAA), the Marine Mammal Commission, the geophysical

contractor and oil & gas industries, and the SWSS Science Review Board. Written summaries of

the SWSS presentations are given in this report. These include the status of the S-tag and Dtag/CEE tasks; discussion of the molecular ecology of sperm whales in the northern Gulf of

Mexico; preliminary results on sperm whale abundance, habitat use, and aspects of social

organization in the northern Gulf of Mexico; summary on tracking sperm whale dive profiles

using a towed passive acoustic array; and preliminary results on habitat characterization

including descriptions of eddy forced variations in on-margin and off-margin summertime

circulation along the 1000-m isobath of the northern Gulf of Mexico, upper-ocean current

observations during summer over the central slopes of the northern Gulf of Mexico, the

midwater trawling program, and 38-kHz ADCP investigation of deep scattering layers.
3

2 INTRODUCTION

The first annual report for the Sperm Whale Seismic Study (SWSS) detailed the program

objectives, tasks, and participants, the data collection and processing for the S-tag and D-tag

cruises in year 1, and the methods for data collection and quality assurance/quality control

(QA/QC), as well as presenting preliminary technical discussions (Jochens and Biggs 2003).

This report focuses on the data collection and analysis efforts during year 2 of the study.

2.1 Program Participants

SWSS is a multi-institutional, interdisciplinary study supported by the Minerals Management

Service (MMS) of the U.S. Department of the Interior under Cooperative Agreement 1435-01-

02-CA-85186 for Cooperative Research on Sperm Whales and their Response to Seismic

Exploration in the Gulf of Mexico. Additional support for SWSS activities is provided by the

Office of Naval Research (ONR), the National Science Foundation (NSF), and the Industry

Research Funders Coalition (IRFC), which is a coalition of the International Association of

Geophysical Contractors (IAGC) and five oil and gas exploration and production companies.

ONR supports tag development. NSF provided year 2 support through grant support to Lamont

Dougherty Earth Observatory (LDEO) for use of the R/V Maurice Ewing in D-tag work for

SWSS 2003. Coordinated efforts with LDEO to calibrate academic and industry air-gun arrays

also were planned and conducted. For the 2003 field year, the IRFC contributed the seismic

source vessel, M/V Kondor Explorer, and its crew used in the Controlled Exposure Experiments

(CEEs) of the D-tag cruise. The seismic source vessel is a critical contribution to the D-tag effort

because it allows controlled exposure experiments with sound from airguns. IRFC also provided

support for calibration tests with Kondor airguns of the Environmental Acoustic Recording

System (EARS) buoy that is part of a separate MMS-sponsored study.

The principal academic SWSS scientists conducting the study are

Ecologic: Jonathan Gordon (also at the University of St. Andrews, UK)

Oregon State University (OSU): Bruce Mate and Joel Ortega-Ortiz

Scripps Institution of Oceanography (SIO): Aaron Thode

Texas A&M University (TAMU): Ann Jochens (SWSS Program Manager), Douglas

Biggs, Matthew Howard, and John Wormuth

Texas A&M University-Galveston (TAMUG): Bernd Würsig and Nathalie Jaquet

University of Colorado (CU): Robert Leben

University of Durham (UD): Daniel Engelhaupt

Woods Hole Oceanographic Institution (WHOI): Peter Tyack, Mark Johnson, and

Patrick Miller (now at the University of St. Andrews, UK)

The principal study tasks and associated institutions are: Satellite-tracked radio tags (S-tags) by

OSU; Digital-recording acoustic tags (D-tags) and CEEs by WHOI; Habitat characterization by

TAMU; Photo-identification and mesoscale population studies by Ecologic and TAMUG;

Biopsy/genetic analyses by UD; 3-D passive acoustic tracking by SIO; Program management by

TAMU; and Data management by TAMU. All activities associated with marine mammals are

conducted pursuant to approved permits from NOAA Fisheries. Additionally, Terry Ketler of

Interactive Educational Network (IEN) is preparing video documentation of the SWSS field

efforts during summer 2003.

A SWSS Science Review Board (SRB) was established to provide review and comments on the

draft Synthesis Report. The SRB consists of one federal representative (Debra Palka, NOAA),

one industry representative (Phil Fontana, Veritas DGC), and three scientific representatives
4

(Daniel Costa of the University of California-Santa Cruz, Robert Hofman retired from the

Marine Mammal Commission, and Doug Wartzok of Florida International University).

2.2 Program Activities for Year 2

The field effort in year 2 consisted of three cruises between May and July 2003. The first two

cruises were conducted concurrently in late May and early June. The D-tag/CEE cruise was

conducted through the coordination of the work on the science vessel R/V Ewing and the seismic

source vessel M/V Kondor. Concurrently, a sperm whale survey and habitat characterization

(WSHC) cruise was conducted aboard the R/V Gyre. All three ships worked cooperatively to

maximize the results obtained during this part of SWSS. The third cruise was the S-tag cruise in

June and July 2003 aboard the R/V Gyre. In addition to the S-tag work, it included habitat

characterization work. Section 3 discusses each of these three cruises and the data collected.

Two new work tasks were initiated in year 2. Aaron Thode of SIO participated on the D-tag/CEE

cruise to conduct experiments on the 3-D passive acoustic tracking of sperm whales. Terry

Ketler of IEN was contracted to prepare a short video documenting the year 2 field work effort.

He participated in both the D-tag and S-tag cruises to conduct filming and interviews.

A number of presentations on SWSS results were made at scientific conferences and two

publications were submitted to and accepted by scientific journals based in part or in whole on

SWSS work. The publications were:

1. "Swimming gaits, passive drag, and buoyancy of diving sperm whales (Physeter

macrocephalus)" by Patrick J.O. Miller, Mark Johnson, Peter L. Tyack, and Eugene A. Terray,

in the Journal of Experimental Biology, 207 (11): 1953-1967.

2. "Tracking sperm whale (Physeter macrocephalus) dive profiles using a towed passive

acoustic array" by Aaron Thode, in the Journal of the Acoustical Society of America, 116 (1),

245-253.

The SWSS-related presentations at science conferences were:

1. Mate, B.R. Seasonal distribution and habitat characterization of sperm whales in the Gulf

of Mexico from Argos satellite-monitored radio tracking. Invited presentation, XV Biennial

Conference on the Biology of Marine Mammals, sponsored by The Society for Marine

Mammalogy, 14-19 December 2003, Greensboro, NC.

2. Biggs, D.C., M.K. Howard, A.E. Jochens, S.F. DiMarco, R.R. Leben, and C. Hu.

Operational applications of satellite altimetry and ocean color to support studies of sperm whale

habitat use in the Gulf of Mexico. AGU Ocean Ocean Sciences Meeting 2004, Portland, OR,

Invited presentation, session OS12C (26 January 2004).

3. Olson, A.M., D.C. Biggs, S.F. DiMarco, and J.H. Wormuth. 38 kHz ADCP investigation

of Gulf of Mexico deep scattering layers. AGU Ocean Sciences Meeting 2004, Portland, OR,

Poster presentation, session OS51E (30 January 2004).

Two other presentations at the AGU Ocean Sciences Meeting 2004 mentioned the SWSS project.

Neither presentation keynoted SWSS data, although SWSS data from summers 2002 and 2003

were used along with other historical data to describe the currents and water properties

(temperature, salinity, nutrients, oxygen) in the northern Gulf of Mexico. These were:
5

1. DiMarco, S.F., A.E. Jochens, N.L. Guinasso, and M.K. Howard. Vertical current

structure of the deepwater Gulf of Mexico from shipboard ADCP observations. Invited

presentation, 27 January 2004.

2. Jochens, A.E., M.K. Howard, and S.F. DiMarco. Recent observations of water properties

in the Gulf of Mexico. Contributed presentation, 27 January 2004.

A number of SWSS presentations were made at the SWSS Workshop and Planning Meeting held

19-21 November 2003. Summaries of these talks are given in section 4.

2.3 Report Organization

This is the second annual report of SWSS. It reports on the data-gathering efforts; changes in

equipment, measurement and analytical methodologies employed; 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 presents brief technical discussions of the data, and, for D-tag, a

discussion of changes in methodology for data collection. Other instrumentation and methods for

data collection, QA/QC, and analysis were as reported in the first SWSS annual report (Jochens

and Biggs 2003). All times are reported in Universal Coordinated Time (UTC) unless stated

otherwise. References are provided in Section 5.
7

3 DATA COLLECTION CRUISES

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

October 2003. It describes data gathering efforts on the cruises. Information on instrumentation,

data collection methods, and data processing procedures are described in Section 4 of Jochens

and Biggs (2003) with augmentation given in the subsections below.

Table 3.0 lists the SWSS field cruises conducted from April 2002 through October 2003.

Information on cruises in 2002 is reported in Jochens and Biggs (2003). Field cruises conducted

in 2003 consisted of, concurrently, a Whale Survey and Habitat Characterization cruise (WSHC)

on the R/V Gyre and a D-tag/CEE cruise aboard the R/V Maurice Ewing and M/V Kondor

Explorer. These were followed by an S-tag/habitat characterization cruise on the R/V Gyre. Also

shown in Table 3.0 is an associated cruise, conducted immediately before and after the Dtag/CEE cruise, to calibrate the airgun array from the EARS buoy. Data collection on each

SWSS cruise is described below.

Table 3.0

Cruises Conducted in 2002 and 2003 for and Related to the Sperm Whale Seismic Study

(Additional cruises are planned for summer 2004.)

Year Ship Cruise Start Date End Date

2002 R/V Gyre S-tag 20 June 2002 8 July 2002

2002 R/V Gyre D-tag 19 August 2002 15 September 2002

2002 M/V Rylan T CEE with Gyre 29 August 2003 12 September 2002

2003 R/V Gyre Habitat survey 31 May 2002 21 June 2003

2003 R/V Maurice Ewing D-tag 3 June 2003 24 June 2003

2003 M/V Kondor Explorer CEE with Ewing 7 June 2003 22 June 2003

2003 M/V Kondor Explorer EARS buoy* 22 June 2003 25 June 2003

2003 R/V Gyre S-tag 26 June 2003 14 July 2003

* EARS is not part of SWSS, but is a sister program supported by MMS and IRFC

3.1 Whale Survey and Habitat Characterization Cruise 2003

The Whale Survey and Habitat Characterization (WSHC) cruise was conducted aboard the R/V

Gyre (cruise 03G06) from 31 May through 21 June 2003. The cruise left Galveston, TX, late

evening on 30 May and returned late evening on 21 June. Field work consisted of a survey for

sperm whales along the middle continental slope (MCS) of the northern Gulf of Mexico between

94.75°W and 86.75°W (Figure 3.1.1). An integral part of the survey effort was to gather physical

and biological oceanographic data for characterization of the oceanographic habitat in which

whales were encountered. Doug Biggs of TAMU was the Field Party Chief and was in charge of

the habitat characterization work. Jonathan Gordon of Ecologic and Nathalie Jaquet of TAMUG

were in charge of the whale survey activities. Dan Engelhaupt of UD was responsible for

collection of tissue samples. Table 3.1.1 lists the cruise participants and their roles. Additional
8

Figure 3.1.1. Ship track for SWSS 2003 WSHC cruise aboard R/V Gyre 31 May – 20 June 2003.

Locations where sperm whales were followed are evidenced by looping track

portions. Contours are shown for the 200, 1000, 2000, and 3000-m isobaths.

information associated with this cruise is in Sections 4.2 (genetic analyses), 4.4 (photoidentification analyses), and 4.6 through 4.9 (habitat characterization).

Previous sperm whale work focused mainly on known areas, such as the Mississippi Canyon and

the deepwater region off the Mississippi River delta, frequented by sperm whales. Since the

Mississippi Canyon was the focal area for CEE activities by the R/V Ewing and M/V Kondor,

which were operating concurrently with R/V Gyre, the WSHC cruise spent little sampling time

there. Rather the WSHC search effort was conducted along the upper slope of the Alaminos

Canyon in the western Gulf and near deepwater production platforms Diana and Hoover, where

sports fishermen had reported seeing sperm whales in summer 2002, as well as in the deepwater

canyons close to the Mississippi River delta. The latter area was of special interest since in May

2003 four of the 18 sperm whales that were tagged in 2002 with satellite-monitored tags were

transmitting back locations in that region. Updated location information on S-tagged whales was

sent by OSU to Gyre every 4 days on WSHC. Several of these radio-tagged animals were

observed during the three weeks of survey.

Because of good success in locating whales in water depths of 800-1000 m during the SWSS

2002 cruises, most of the visual and acoustic search effort this cruise was centered in the same

range. However, water depths between 500 m and 1430 m also were searched.

Both acoustic and visual techniques were used to search for sperm whales as the cruise surveyed

the MCS. Matched Ecologic tandem two-hydrophone arrays were towed, one off the port quarter

and the other off the starboard quarter of the stern, for over 360 hours. BigEyes were generally
9

Table 3.1.1

Science Personnel for SWSS 2003 WSHC Cruise Aboard the R/V Gyre

Description Personnel Institution

Field Party Chief Doug Biggs (Oceanography team leader) TAMU

Acoustic Team Ricardo Antunes (Team Leader) Whale Museum, PT

Sarah Tsoflias MMS

Sonia Mendez Portugal

Jon Vallarta Mexico

Photography, Nathalie Jaquet (Team Co-Leader) TAMUG

Photogrammetry, Jonathan Gordon (Team Co-Leader) Ecologic Ltd., UK

and Small Boat Will Rayment Univ. Otago, NZ

 Acoustics Christoph Richter Queens Univ., ONT

Visual Team Erin LaBrecque (Team Leader) TAMU

Jamie McKee SAIC, Shalimar, FL

Mark Tasker JNCC*, Aberdeen, UK

Trudi Webster New Zealand

Simon Mustoe AES*, Melbourne, AU

Thom Gordon United Kingdom

Trawling Team John Wormuth (Team Leader) TAMU

Steve Berkowitz CCU*, South Carolina

Andrey Mishonov MUGC*, RU

Biopsy Dan Engelhaupt Durham Univ., UK

Oceanography Amanda Olson TAMU

TAMU Technicians Eddie Webb (Electronics Technician) TAMU

Paul Clark (Electronics Technician) TAMU

Bill Green (Deck Engineer) TAMU

Mike Fredericks (Deck Engineer) TAMU

* JNCC = Joint Nature Conservation Committee; AES = Applied Ecology Solutions, Pty Ltd.;

CCU = Coastal Carolina Univ.; MUGC = Moscow University for Geodesy & Cartography

manned from 05:50 - 19:30 CDT each day, except during rain squalls or when breeze and sea

conditions exceeded Beaufort 4. Total visual search time was over 200 hours. Two rigid-hulled

inflatable boats (RHIBs) were deployed when weather and sea conditions allowed for photoidentification and photogrammetry. During the 3 week period of the survey over the MCS, one

or both small boats were launched on 18 days. On most of these days, sperm whales were

encountered in groups of 3-16 animals. Figure 3.1.2 overlays on the daytime part of the ship

track the locations where whales were observed by visual observers. Although most of the

whales were seen in water depths between 800 m and 1000 m, they also were heard or seen in

water depths both shallower (to 600 m) and deeper (to 1300 m).
10

Figure 3.1.2. Locations of visual sightings of sperm whales (dots) on the SWSS 2003 WSHC

cruise in May/June 2003 superimposed over the daytime cruise track (light gray

line). Contours are shown for the 200, 1000, 2000, and 3000-m isobaths.

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. Ocean current velocity in the upper 300

m and upper 900 m was monitored continuously with RD Instruments hull-mounted 153 kHz

ADCP and 38 kHz ADCP, respectively. At 8 locations, CTD casts were made with a SeaBird

Electronics SeaCat internally-recording CTD to record profiles of conductivity (salinity) and

temperature with depth. Eighty-nine XBTs were dropped to profile temperature in the upper 760

m. These generally were dropped every 10 nautical miles (18 km), although on days when

whales were being followed, XBTs usually were dropped more frequently to obtain finer spatial

resolution. Sippican Deep Blue XBTs were dropped during the first ten days of the cruise and

Sippican T7 XBTs were used to complete the rest of the survey.

Photo-ID/Photogrammetry and Biopsy/Genetic Typing activities were conducted in accordance

with federal permits from NOAA Fisheries to Texas A&M University-Galveston (permit 821-

1588-00), and to Dan Engelhaupt/University of Durham (permit 909-1465-02).

Oceanographic Habitat

The habitat characterization work was coordinated by Doug Biggs. The pre-cruise map of sea

surface height (SSH) for 28 May 2003 indicated that SSH over the slope and in deepwater was

higher than SSH over the shelf. Thus, surface currents over the middle continental slope were

expected to flow generally from west to east.

The SSH analysis further indicated that the western edge of a very large deepwater anticyclonic

(clockwise circulating) Loop Current eddy (LCE) was located near 27.5°N, 91°W. The LCE was
11

named Eddy Sargassum by the oil and gas industry service company that tracks the Loop Current

and its associated eddies. The altimetry indicated this LCE, which had separated from the Loop

Current only a few weeks before the ship sailed, had an SSH anomaly of > 40 cm and that to its

north there was an area of cyclonic circulation where SSH dipped as low as –20 cm. When

combined, these extrema correspond to a gradient of SSH of > 60 cm across a distance of less

than 30 nautical miles. Thus, it was expected that very strong surface currents would be

encountered as the ship transited the western and northern periphery of this big LCE.

Because the location of this big LCE in the SSH analysis of 28 May showed its northern edge

reached mid-slope water depths, it was anticipated that strong clockwise surface currents around

the LCE would block Mississippi River water from flowing to the west. From this geometry, it

was expected that the clockwise circulation around the LCE would entrain the low salinity,

higher chlorophyll shelf water near the mouth of the Mississippi River and transport this "green"

water to the east and off the margin into DeSoto Canyon. Subsequent SSH analyses for 8, 15,

and 17 June showed this same general geometry, but also showed that from May to June the

northern periphery of the LCE was moving increasingly up slope between 91°W and 89°W.

The locations, dates, times, and 15°C isotherm depths of the CTD and XBT stations are given in

Tables 3.1.2 and 3.1.3, respectively. Figure 3.1.3 shows a map of the locations. Temperature,

salinity, and fluorescence from a depth of ~3.5 m were logged once per minute throughout the

cruise. The sample locations are shown in Figure 3.1.4. The locations, dates, and times of the

chlorophyll samples are given in Table 3.1.4, with the map of locations given in Figure 3.1.4.

These samples are used to calibrate the continuous fluorescence data. ADCP data were collected

continuously along the track generally in water depths of about 15 m or more for the 153 kHz

ADCP and about 35 m or more for the 38 kHz ADCP.

Data from the flow-through system, XBT drops, CTD stations, and ADCPs confirmed the

intensity of the SSH gradient across Eddy Sargassum and its capture of Mississippi River water

and eastward transport of that low salinity water. West of 93°W and east of 88.5°W, the surface

salinity was generally less than 35 and the water was visibly greenish in color. Chlorophyll

fluorescence in this "green" water exceeded 165 mvolts, equivalent to > 0.25 μg chlorophyll·L-1. In many locations along the track between 93°W and 88.5°W, surface salinity was greater than

36. Here, the water was azure blue in color and chlorophyll fluorescence was generally < 130

mvolts, equivalent to < 0.15 μg chlorophyll·L-1. The exception, however, was where the surface

current exceeded 2 knots in the periphery of Eddy Sargassum. In these areas, chlorophyll

fluorescence reached 185 mvolts, or about 0.3 μg chlorophyll·L-1 and so was roughly double the

maximum of 0.15 μg chlorophyll·L-1 found within Eddy Sargassum.

Whales were heard and/or seen both in green water and in blue water environments. Many of the

encounters with whales were at or near the high velocity periphery of this big LCE. Other

concentrations of whales were found in the areas of cyclonic circulation at 93-94°W along the

upper reaches of Alaminos Canyon and at 87-88°W near the head of DeSoto Canyon.

Visual Survey and Monitoring

A visual observation station was established on the flying bridge. It consisted of two standmounted 25x BigEye binoculars and a data entry station. At least three observers maintained a

continuous watch during daylight hours, generally 05:50–19:30 CDT, while the ship surveyed or

tracked whales in water depths greater than 500 m. A rolling two-hour watch system was

implemented. This provided the observers with sufficient breaks to maintain motivation and

vigilance while ensuring that an appreciation of the whales' general behavior and activity

patterns was preserved and transferred within the bridge team as it gradually changed over the

day. During "busy periods", for example when members of a large group were being tracked,

"resting" observers would be drafted in to provide assistance.
12

Table 3.1.2

Summary of CTD Stations on SWSS 2003 WSHC Cruise

Station Date

(mm/dd/yyyy)

Time

(UTC)

Longitude

(°W)

Latitude

(°N)

15°C

Depth (m)

CTD-01 05/31/2003 20:30 -94.753 27.505 218

CTD-02 06/03/2003 05:46 -93.818 27.186 194

CTD-03 06/04/2003 06:36 -93.936 27.344 203

CTD-04 06/10/2003 02:56 -90.470 27.470 225

CTD-05 06/11/2003 05:13 -88.924 28.414 242

CTD-06 06/13/2003 05:53 -87.667 29.048 166

CTD-07 06/14/2003 02:41 -86.945 28.685 168

CTD-08 06/16/2003 06:47 -88.741 28.486 282

Table 3.1.3

Summary of XBT Stations on SWSS 2003 WSHC Cruise

Station Date

(mm/dd/yyyy)

Time

(UTC)

Longitude

(°W)

Latitude

(°N)

15°C

Depth (m)

XBT-1 06/01/2003 15:55 -94.582 27.595 216

XBT-2 06/01/2003 17:41 -94.747 27.601 240

XBT-3 06/01/2003 19:22 -94.750 27.443 241

XBT-4 06/01/2003 21:00 -94.755 27.276 249

XBT-5 06/01/2003 22:38 -94.769 27.109 258

XBT-6 06/01/2003 23:58 -94.788 26.977 245

XBT-7 06/02/2003 02:16 -94.546 26.981 236

XBT-8 06/02/2003 05:59 -94.398 27.080 229

XBT-9 06/02/2003 11:57 -94.246 27.163 223

XBT-10 06/02/2003 14:08 -94.150 27.306 224

XBT-11 06/02/2003 16:26 -94.039 27.424 206

XBT-12 06/03/2003 00:16 -93.893 27.426 202

XBT-13 06/03/2003 02:16 -93.828 27.277 223

XBT-14 06/03/2003 13:32 -93.975 27.386 208

XBT-15 06/03/2003 16:08 -94.036 27.557 178

XBT-16 06/03/2003 18:07 -93.860 27.542 176

XBT-17 06/04/2003 21:48 -93.745 27.377 213

XBT-18 06/05/2003 09:24 -93.601 27.440 200

XBT-19 06/05/2003 11:34 -93.401 27.468 213

XBT-20 06/05/2003 13:51 -93.189 27.446 205

XBT-21 06/05/2003 18:35 -93.027 27.457 191

XBT-22 06/06/2003 13:16 -92.868 27.297 199
13

Table 3.1.3

Summary of XBT Stations on SWSS 2003 WSHC Cruise (continued)

Station Date

(mm/dd/yyyy)

Time

(UTC)

Longitude

(°W)

Latitude

(°N)

15°C

Depth (m)

XBT-23 06/06/2003 15:11 -92.699 27.227 210

XBT-24 06/06/2003 17:10 -92.531 27.148 218

XBT-25 06/06/2003 19:21 -92.340 27.225 237

XBT-26 06/06/2003 21:20 -92.178 27.297 248

XBT-27 06/06/2003 23:36 -92.002 27.369 252

XBT-28 06/07/2003 02:14 -91.824 27.379 241

XBT-29 06/07/2003 05:09 -91.810 27.214 245

XBT-30 06/07/2003 09:08 -91.656 27.313 228

XBT-31 06/07/2003 10:52 -91.541 27.445 223

XBT-32 06/07/2003 12:38 -91.430 27.579 194

XBT-33 06/07/2003 14:33 -91.309 27.718 195

XBT-34 06/07/2003 17:34 -91.158 27.614 203

XBT-35 06/07/2003 19:28 -91.012 27.502 216

XBT-36 06/07/2003 21:30 -90.865 27.391 229

XBT-37 06/08/2003 00:28 -90.657 27.403 227

XBT-38 06/08/2003 17:24 -90.671 27.466 221

XBT-39 06/09/2003 02:06 -90.601 27.585 211

XBT-40 06/09/2003 13:27 -90.444 27.576 252

XBT-41 06/09/2003 20:57 -90.489 27.518 242

XBT-42 06/10/2003 05:03 -90.275 27.615 274

XBT-43 06/10/2003 06:11 -90.112 27.706 298

XBT-44 06/10/2003 07:25 -89.943 27.801 309

XBT-45 06/10/2003 08:25 -89.768 27.863 323

XBT-46 06/10/2003 09:27 -89.599 27.965 326

XBT-47 06/10/2003 10:43 -89.387 28.079 320

XBT-48 06/10/2003 11:49 -89.200 28.165 326

XBT-49 06/10/2003 16:00 -89.046 28.289 321

XBT-50 06/11/2003 08:32 -88.795 28.545 227

XBT-51 06/11/2003 10:06 -88.642 28.651 212

XBT-52 06/12/2003 06:04 -88.558 28.810 192

XBT-53 06/12/2003 07:21 -88.376 28.897 195

XBT-54 06/12/2003 08:35 -88.204 28.979 177

XBT-55 06/12/2003 09:57 -88.003 29.067 174

XBT-56 06/12/2003 11:04 -87.827 29.137 189

XBT-57 06/12/2003 12:55 -87.654 29.214 173

XBT-58 06/13/2003 12:54 -87.480 29.144 162

XBT-59 06/13/2003 14:57 -87.360 29.014 157

XBT-60 06/13/2003 16:52 -87.228 28.890 169

XBT-61 06/13/2003 19:54 -87.098 28.761 163

XBT-62 06/13/2003 21:58 -86.959 28.683 172

XBT-63 06/14/2003 13:55 -86.991 28.500 152

XBT-64 06/14/2003 15:53 -87.052 28.336 155
14

Table 3.1.3

Summary of XBT Stations on SWSS 2003 WSHC Cruise (continued)

Station Date

(mm/dd/yyyy)

Time

(UTC)

Longitude

(°W)

Latitude

(°N)

15°C

Depth (m)

XBT-65 06/14/2003 19:21 -86.901 28.457 161

XBT-66 06/14/2003 23:24 -86.776 28.317 164

XBT-67 06/15/2003 07:09 -87.169 28.553 165

XBT-68 06/15/2003 10:06 -87.336 28.662 189

XBT-69 06/15/2003 23:45 -87.237 29.142 178

XBT-70 06/16/2003 05:32 -87.615 29.008 198

XBT-71 06/16/2003 06:47 -87.804 28.969 206

XBT-72 06/16/2003 22:27 -88.935 28.734 213

XBT-73 06/17/2003 15:50 -88.960 28.580 256

XBT-74 06/17/2003 19:00 -89.055 28.639 253

XBT-75 06/19/2003 04:11 -89.073 28.476 267

XBT-76 06/19/2003 05:58 -89.184 28.330 283

XBT-77 06/19/2003 07:30 -89.373 28.315 271

XBT-78 06/19/2003 09:12 -89.543 28.231 260

XBT-79 06/19/2003 10:47 -89.699 28.134 273

XBT-80 06/19/2003 12:19 -89.827 28.007 259

XBT-81 06/19/2003 14:52 -89.990 27.921 241

XBT-82 06/19/2003 17:08 -90.157 27.841 216

XBT-83 06/19/2003 19:10 -90.323 27.752 250

XBT-84 06/19/2003 21:31 -90.467 27.667 240

XBT-85 06/20/2003 00:49 -90.440 27.794 229

XBT-86 06/20/2003 12:04 -90.620 27.682 228

XBT-87 06/20/2003 15:29 -90.898 27.665 204

XBT-88 06/20/2003 20:56 -90.959 27.798 194

XBT-89 06/20/2003 22:17 -91.130 27.868 178
15

Figure 3.1.3. Locations of CTD (square) and XBT (plus) stations on SWSS 2003 WSHC cruise.

Contours are shown for the 200, 1000, 2000, and 3000-m isobaths.

Figure 3.1.4. Locations of chlorophyll samples on the SWSS 2003 WSHC cruise. Contours are

shown for the 200, 1000, 2000, and 3000-m isobaths.
16

Table 3.1.4

Chlorophyll Stations on SWSS 2003 WSHC Cruise

Date

(mm/dd/yyyy)

Time

(UTC)

Nearest

Station

Longitude

(°W)

Latitude

(°N)

05/31/2003 20:38 CTD-01 -94.750 27.504

06/01/2003 02:32 underway -94.587 27.455

06/01/2003 07:05 underway -94.599 27.459

06/01/2003 16:13 XBT-1 -94.599 27.605

06/01/2003 17:51 XBT-2 -94.753 27.600

06/01/2003 19:29 XBT-3 -94.751 27.432

06/01/2003 21:03 XBT-4 -94.755 27.270

06/01/2003 22:38 XBT-5 -94.769 27.108

06/02/2003 00:00 XBT-6 -94.788 26.973

06/02/2003 02:41 XBT-7 -94.531 26.983

06/02/2003 06:01 XBT-8 -94.396 27.081

06/02/2003 13:51 XBT-9 -94.168 27.284

06/02/2003 14:13 XBT-10 -94.145 27.312

06/02/2003 16:15 XBT-11 -94.051 27.411

06/02/2003 22:16 low salinity -93.959 27.332

06/03/2003 00:16 XBT-12 -93.891 27.424

06/03/2003 04:10 XBT-13 -93.824 27.261

06/03/2003 10:08 underway -93.873 27.332

06/03/2003 13:32 XBT-14 -93.977 27.387

06/03/2003 16:06 XBT-15 -94.041 27.556

06/03/2003 20:58 XBT-16 -93.852 27.404

06/04/2003 06:19 CTD-03 -93.916 27.350

06/04/2003 16:02 underway -94.015 27.393

06/04/2003 17:35 underway -93.923 27.421

06/04/2003 21:48 XBT-17 -93.745 27.377

06/05/2003 12:23 XBT-19 -93.324 27.463

06/05/2003 13:21 underway -93.235 27.458

06/05/2003 13:48 XBT-20 -93.194 27.448

06/05/2003 17:41 underway -93.067 27.462

06/05/2003 18:13 XBT-21 -93.046 27.464

06/06/2003 00:30 underway -92.981 27.419

06/06/2003 05:14 CTD -93.014 27.439

06/06/2003 13:13 XBT-22 -92.871 27.298

06/06/2003 15:09 XBT-23 -92.701 27.228

06/06/2003 17:02 XBT-24 -92.540 27.153

06/06/2003 19:22 XBT-25 -92.337 27.227

06/06/2003 21:20 XBT-26 -92.179 27.297

06/06/2003 23:46 XBT-27 -91.988 27.377

06/07/2003 02:14 XBT-28 -91.823 27.378

06/07/2003 10:58 XBT-31 -91.535 27.453

06/07/2003 12:39 XBT-32 -91.429 27.579
17

Table 3.1.4

Chlorophyll Stations on SWSS 2003 WSHC Cruise (continued)

Date

(mm/dd/yyyy)

Time

(UTC)

Nearest

Station

Longitude

(°W)

Latitude

(°N)

06/07/2003 14:32 XBT-33 -91.312 27.718

06/07/2003 19:27 XBT-35 -91.015 27.504

06/07/2003 21:33 XBT-36 -90.844 27.388

06/08/2003 00:28 XBT-37 -90.655 27.403

06/08/2003 15:50 underway -90.747 27.480

06/08/2003 17:24 XBT-38 -90.671 27.466

06/09/2003 02:07 XBT-39 -90.790 27.585

06/09/2003 13:26 XBT-40 -90.445 27.575

06/09/2003 20:57 XBT-41 -90.488 27.518

06/10/2003 02:55 CTD-04 -90.473 27.506

06/10/2003 11:07 XBT-47 -89.316 28.108

06/10/2003 11:46 XBT-48 -89.203 28.165

06/10/2003 15:55 XBT-49 -89.048 28.292

06/11/2003 04:57 CTD-05 -88.930 28.411

06/11/2003 08:38 XBT-50 -88.793 28.550

06/11/2003 10:06 XBT-51 -88.642 28.650

06/11/2003 13:48 on whales -88.649 28.776

06/12/2003 05:57 XBT-52 -88.577 28.800

06/12/2003 06:09 rising fluor -88.545 28.816

06/12/2003 07:23 XBT-53 -88.376 28.897

06/12/2003 07:36 high fluor -88.341 28.914

06/12/2003 08:48 XBT-54 -88.172 28.994

06/12/2003 09:57 XBT-55 -88.004 29.066

06/12/2003 11:03 XBT-56 -87.826 29.137

06/12/2003 12:53 XBT-57 -87.656 29.212

06/13/2003 00:19 on whales -87.839 28.972

06/13/2003 05:46 CTD-6 -87.668 29.045

06/13/2003 12:22 S gradient -87.514 29.177

06/13/2003 12:56 XBT-58 -87.477 29.141

06/13/2003 14:26 S gradient -87.389 29.037

06/13/2003 14:53 XBT-59 -87.363 29.017

06/13/2003 16:08 S gradient -87.277 28.938

06/13/2003 16:48 XBT-60 -87.232 28.894

06/13/2003 17:25 S gradient -87.184 28.856

06/13/2003 19:54 XBT-61 -87.096 28.760

06/13/2003 21:59 XBT-62 -86.958 28.688

06/14/2003 14:03 XBT-63 -86.994 28.489

06/14/2003 16:03 XBT-64 -87.043 28.326

06/14/2003 22:27 near whale -86.805 28.349

06/15/2003 07:40 XBT-67 -87.186 28.559

06/15/2003 10:02 XBT-68 -87.332 28.659
18

Table 3.1.4

Chlorophyll Stations on SWSS 2003 WSHC Cruise (continued)

Date

(mm/dd/yyyy)

Time

(UTC)

Nearest

Station

Longitude

(°W)

Latitude

(°N)

06/15/2003 17:22 on whales -87.191 28.782

06/15/2003 23:47 XBT-69 -87.233 29.142

06/16/2003 05:31 XBT-70 -87.615 29.007

06/16/2003 06:56 XBT-71 -87.826 28.965

06/16/2003 15:48 underway -88.664 28.702

06/16/2003 22:24 XBT-72 -88.934 28.732

06/17/2003 06:43 CTD-8 -88.744 28.486

06/17/2003 15:55 XBT-73 -88.965 28.575

06/17/2003 23:12 underway -88.853 28.705

06/18/2003 13:57 underway -88.900 28.740

06/18/2003 19:03 XBT-74 -89.056 28.640

06/18/2003 19:32 front -89.066 28.657

06/18/2003 20:49 near whales -89.007 28.681

06/19/2003 04:12 XBT-75 -89.075 28.472

06/19/2003 07:30 XBT-77 -89.373 28.315

06/19/2003 9:32 XBT-78 -89.581 28.215

06/19/2003 10:52 XBT-79 -89.707 28.127

06/19/2003 12:17 XBT-80 -89.824 28.009

06/19/2003 13:04 underway -89.875 27.986

06/19/2003 14:52 XBT-81 -89.990 27.921

06/19/2003 17:08 XBT-82 -90.157 27.841

06/19/2003 19:10 XBT-83 -90.322 27.752

06/19/2003 21:31 XBT-84 -90.467 27.667

06/20/2003 01:03 XBT-85 -90.444 27.805

06/20/2003 12:03 XBT-86 -90.622 27.681

06/20/2003 15:29 XBT-87 -90.903 27.678

06/20/2003 20:56 XBT-88 -90.959 27.799

06/20/2003 22:19 XBT-89 -91.135 27.870

While on watch, observers moved between roles on the flying bridge every 40 minutes. Two

observers scanned with BigEye binoculars, hand-held binoculars, and/or by naked eye. The third

person, the data recorder, concentrated on the near field using only naked eye and 7x50

binoculars. The data recorder also entered data into the Logger program on a laptop computer.

Logger is a data collection and depiction software program written by Douglas Gillespie and

made freely available by the International Fund for Animal Welfare to assist marine conservation

projects. The watch order was chosen so that observers with complimentary skills and levels of

experience were distributed through the rotation. While tracking sperm whales, the watch

rotation was adapted to facilitate the need for at least one extra person on the flying bridge to

handle radio communications.
19

The Gyre carried two rigid-hull inflatable boats (RHIBs) for this cruise: RHIB-1 was a 25-foot

Zodiac Hurricane powered by an inboard Volvo diesel, and RHIB-2 was an 18-foot Avon

Searider powered by a 70 Hp Johnson two stroke outboard. The visual team on Gyre worked in

different modes depending on whether the acoustic team was tracking sperm whales at sunrise

(track mode) and/or a RHIB was deployed. The vessel might be either searching for whales or,

once they had been found, tracking them. In "line survey" searching mode, the vessel followed

predetermined tracks and the visual team followed survey procedures that matched closely those

used by NOAA Fisheries for line transect surveys. When the team was searching for whales but

not following predetermined survey tracks or when the RHIBs were launched to search for

whales acoustically, visual effort was scored as simply "searching". Another searching mode,

termed "hunch", was in place when searching was directed to a predetermined area believed to

contain whales (e.g., when searching an area reported to have a satellite tagged whale). While

searching, the visual team operated independently from the acoustic team so that data on relative

detection efficiencies of visual and acoustic methods could be collected.

Once sperm whales were detected the visual team's primary role became that of tracking the

locations and movements of whales and helping the RHIBs to get close to them for photo-ID or

biopsy. The locations of all first sightings and final submergences and/or fluke-ups were

recorded in Logger, along with notes on any behaviors observed by the visual team and/or

behaviors reported by RHIB teams. These data also provide detailed information on group

movements and distributions.

In track mode the visual and acoustic teams worked closely together. The aim was to

amalgamate all information on the location and behavior of whales (visual data, acoustic data

from the Gyre’s arrays, and acoustic information from the RHIB boats' directional hydrophones)

to form a comprehensive view of the whales' movements and behavior. The visual team also

requested course and speed changes from the Gyre bridge to keep the vessel in a position so its

visual coverage of whale groups, which typically spread over several miles, was optimal. The

understanding and good humor that the officers on the Gyre bridge showed in responding to the

numerous requests of the scientists for course changes, while navigating the vessel safely around

other shipping and oil rigs, are acknowledged.

Over 200 hours were spent on survey effort during which time the vessel covered over 800

miles. These hours are broken down by effort category in Table 3.1.5. It can be seen that more

than half of the entire visual effort was expended in tracking groups of sperm whales. Table 3.1.6

provides a more detailed breakdown showing effort expended in each category for different sea

states. Locations of sperm whale sightings during line survey, searching, and tracking modes are

summarized in Figure 3.1.2. In Figure 3.1.5 are shown locations of sightings of pilot whale

(Globicephala macrorhynchus), melon-headed whale (Peponocephala electra), pygmy/dwarf

sperm whale (Kogia sp.), a mixed school of melon-headed whale, rough-toothed dolphin and

Fraser’s dolphin (P. electra, Steno bredanensis and Lagenodelphis hosei), unidentified blackfish,

and unidentified whale sightings and pantropical spotted dolphins (Stenella attenuata), and

unidentified dolphins (some schools could not be identified while tracking sperm whales). Table

3.1.7 provides a listing of associated locations.

Sperm whales were sighted in all the major search areas along the continental slope. No whales

were found in the Mississippi Canyon this year, but virtually no daytime effort was expended in

this area to avoid any possibility of interference with the CEE work of the Ewing and Kondor.

Use of RHIBs

Use of RHIBs to increase sperm whale detection range: On days when the weather was favorable

but sperm whales had not been located either visually or acoustically by the Gyre, search

efficiency was increased by dispatching one or both of the RHIBs to listen with their stereo

dipping hydrophones. Usually RHIBs were launched to acoustically monitor at stations
20

approximately 3 miles apart. A pair of omni-directional hydrophones (Hi Tech HTI-96-MIN)

with amplifier/conditioner in a water proof case was available for each RHIB for this purpose.

Table 3.1.5

Synopsis of Nautical Miles and Hours of Effort Status

Effort Status Nautical Miles

of Trackline

Hours of

Effort

Track 363.3 122.2

Line 251.1 49.1

Search 175.7 38.9

Hunch 7.3 1.4

Off effort 18.4 5.0

Total 815.8 216.6

Table 3.1.6

Nautical Miles and Hours of Effort for Each Effort Status by Sea State

Effort

Status

Beaufort

Sea State

Nautical Miles

of Trackline

Hours of

Effort

Line 2 102.9 20.2

3 107.2 20.8

3.5 26.5 5.0

4 14.5 3.0

Searching 1 6.8 2.0

2 108.5 23.1

3 55.3 11.9

3.5 3.5 1.3

4 1.5 0.7

Tracking 1 34.9 13.0

2 125.4 42.3

3 142.7 45.0

3.5 28.0 9.9

4 32.2 11.9

Hunch 3 7.3 1.4

Note: Sea State 3.5 has white caps just beginning to form, which decreased searching/sighting ability.
21

Table 3.1.7

Locations of Sightings of Toothed Whales and Delphiniids on SWSS 2003 WSHC Cruise

Species Names Longitude

(°W)

Latitude

(°N)

Kogia sp -90.733 27.545

Melon-Headed Whale -94.036 27.442

Melon-Headed Whale -87.039 28.353

Melon-Headed Whale -86.825 28.379

Mixed Group* -87.016 28.350

Pilot Whale -94.732 27.607

Pilot Whale -92.989 27.433

Pilot Whale -88.895 28.689

Pilot Whale -91.053 27.836

Unidentified Blackfish -91.094 27.568

Unidentified Blackfish -88.542 28.766

Unidentified Whale -90.727 27.399

Pantropical Spotted Dolphin -94.155 27.300

Pantropical Spotted Dolphin -90.533 27.473

Pantropical Spotted Dolphin -90.587 27.455

Pantropical Spotted Dolphin -90.588 27.453

Pantropical Spotted Dolphin -90.606 27.425

Pantropical Spotted Dolphin -90.590 27.443

Pantropical Spotted Dolphin -90.488 27.538

Pantropical Spotted Dolphin -89.088 28.289

Pantropical Spotted Dolphin -89.095 28.276

Pantropical Spotted Dolphin -86.993 28.664

Pantropical Spotted Dolphin -86.976 28.573

Pantropical Spotted Dolphin -86.991 28.500

Pantropical Spotted Dolphin -86.828 28.417

Pantropical Spotted Dolphin -90.878 27.655

Unidentified Dolphin -94.050 27.429

Unidentified Dolphin -90.509 27.519

Unidentified Dolphin -90.476 27.524

Unidentified Dolphin -86.957 28.670

Unidentified Dolphin -86.982 28.547

Unidentified Dolphin -86.986 28.529

Unidentified Dolphin -86.997 28.482

Unidentified Dolphin -86.854 28.440

Unidentified Dolphin -86.845 28.433

Unidentified Dolphin -88.433 28.838

Unidentified Dolphin -88.940 28.735

Unidentified Dolphin -88.993 28.661

Unidentified Dolphin -88.974 28.687

Unidentified Dolphin -89.793 28.041

Unidentified Dolphin -89.842 27.995

Unidentified Dolphin -90.407 27.711

*Melon-headed, rough-toothed, Frasier’s mixed group
22

Figure 3.1.5. Visual sightings of toothed whales and delphiniids on the SWSS 2003 WSHC

cruise. Shown are (a) Kogia sp.; (b) melon-headed whale; (c) melon-headed,

rough-toothed, Frasier's mixed group; (d) pilot whale; (e) unidentified blackfish;

(f) unidentified whale; (g) pantropical spotted dolphin; (h) unidentified dolphin.

Contours are shown for the 200, 1000, 2000, and 3000-m isobaths.

Typically the RHIBs would parallel the course of the Gyre about 3 miles abeam and stop to

monitor for 5-10 minutes every three miles. Once whales were detected, a directional

hydrophone was used to close on the whales and the Gyre closed with the RHIB for support.

When operated in this mode, the RHIB greatly extended the effective acoustic swath and when in

use, RHIBs usually made the first detection of whales. Once, when listening conditions were

very favorable, a group of whales were detected at an estimated range of 10 miles.

Out of the 20 days of survey over the MCS during this cruise, sperm whales were seen and/or

heard on 18 days, and one or both RHIBs were deployed on 17. On ten of these days, visual

contact was made with whales between 6 AM and 8 AM local time. On the other eight days, a

RHIB was launched as soon as the weather allowed, and whales were always found by the RHIB

away team before the end of the day. On only one occasion, when both RHIBs developed engine
23

problems, could whales not be followed. On another occasion, whales were detected late in the

day and not tracked down until approximately 19:45 CDT by which time the declining daylight

was not suitable for photo-identification. On the 2 days that whales were neither seen nor heard

(1 and 6 June), the science team effectively was weathered out. The sea was too rough for

launching even RHIB 2, and the visual team was off effort for part of these days because of

heavy rainfall.

It is clear that dispatching one or both of the RHIBs abeam of the Gyre significantly increases

detection range, and several groups of sperm whales would not have been detected if the RHIBs

had not been used in conjunction with the visual and acoustic teams onboard.

Use of RHIBs for photo-identification, recordings and behavioral observations: For photo-ID,

the smaller Avon was found to be the preferable RHIB. It was easier to launch and could often

be put in the water in weather that precluded the deployment of the larger RHIB 1. It was more

responsive and maneuverable. It also was more comfortable as the larger RHIB 2 tended to slam

in moderate seas. Weather permitting, RHIB 2 was launched whenever sperm whales were

sighted. RHIB 1 was only occasionally launched to increase data collection when the team was

with a significantly large or spread out group of whales. The limited times in which both RHIBs

were launched was partly because of the practical and weather restrictions mentioned above, but

also because only one of the two digital cameras available for photo-ID was really fit for the

purpose. Both of the RHIBs were 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 fluke identification photographs. RHIBs were equipped with

palmtop computers (HP 200 XL) in water-proof housings linked to a GPS (Garmin 76) which

allowed the detailed track of the boat as well as the position of whales to be recorded accurately.

Photo-Identification

Identification photographs were taken using the digital EOS 1D Canon Camera with a Sigma

100-300 mm telephoto lens, and with the Fuji FinePix with a Tokina 300 mm lens. Ranges to

whales were measured using Bushnell 1000 laser range finders. The system based on the Canon

EOS1D, which can shoot at 8 frames per second (fps), was ideal. The system based on the Fuji

FinePix was restricted by a low frame rate (<2 fps) and also suffered from a software bug that

caused it to occasionally freeze up.

Of the 20 days spent surveying, 17 days in total were spent with sperm whales in conjunction

with the small boat operations for photo-ID and/or biopsy. Some of these days were

unfortunately cut short due to either bad weather (e.g., 2 and 17 June) or because whales were

found late in the day (e.g., 3, 14, and 16 June) or both (e.g., 19 June).

The majority of the whale aggregations located this year were rather small (6-10 individuals).

Large assemblages of sperm whales (15-20+ individuals) were found only off the Mississippi

River delta area on 17 and 18 June. Only one apparently lone animal was encountered (14 June).

Total length of this individual was estimated as only 9.8 meters using fluke photogrammetry.

Small groups of approximately 3 whales were identified in the western Gulf (3 and 19 June).

Analyses of the available photogrammetry data are underway to determine if the individual

animals in these groups may have been small males or large immature males. When genetics

results from biopsy samples taken 3 June are analyzed, these should add significantly to the final

analysis.

A total of 152 photo-identification sequences were taken with up to 24 IDs obtained in a single

day (Table 3.1.8). Seventy-nine different sperm whale individuals were identified during this 3

week cruise and 65 of these had images of sufficiently high quality to be used to estimate sperm

whale population in the northern Gulf using mark-recapture techniques. Others were represented

by images that are good enough to be used for less exacting photo-identification analyses.
24

Table 3.1.8

Synopsis of Fluke-Out Sequences for Photo-ID

Date

(mm/dd/yyyy)

# of ID

Sequences

# of Animals

Determined to be

Different

Individuals

# of Different

Individuals with High

Quality Identification

Photograph

06/02/2003 1 1 1

06/03/2003 6 3 3

06/04/2003 7 7 4

06/05/2003 8 4 2

06/08/2003 17 5 4

06/09/2003 10 6 6

06/10/2003 13 5 5

06/11/2003 11 7 7

06/12/2003 13 5 5

06/14/2003 3 1 1

06/15/2003 18 8 7

06/16/2003 5 3 2

06/17/2003 9 6 5

06/18/2003 24 16 11

06/19/2003 1 1 1

06/20/2003 6 5 5

Total 152 83 69

At the end of 2002, the sperm whale catalogue for the Gulf of Mexico, which contains images

collected over the eight years between 1994 and 2002, contained 96 individuals represented by

good quality photo-identification photographs. This three-week survey on which photo-ID was

one of several research priorities has made a significant contribution to the catalogue by

contributing 57 new individuals (duplicate individuals have already been discounted). The Gulf

of Mexico catalogue now stands at a total of 153 individual sperm whales.

Resightings of Satellite Tagged Whales

Five of the 18 whales that were radio-tagged on the SWSS 2002 S-tag cruise were still

transmitting their locations on a four-day cycle in mid-May 2003. Four of these radio-tagged

whales were located close off the Mississippi River delta. On 18 June, the survey position was

less than 5 miles from where one of these tagged animals had transmitted just hours earlier. The

group of whales sighted and followed with small boats on 18 June in fact included 3 whales with

satellite tags. Photographs of the tag and attachment area were taken for each individual and 2 of

the 3 animals could be photo-identified. The third tagged animal, which persistently performed

low fluke-up dives, could not be adequately photographed. Other satellite-tagged whales were

also seen on other occasions on the cruise, but due to rough weather good photographs could not

be obtained.
25

Length Measurements

To estimate sperm whale total length, which might allow an assessment of population age

structure, 87 photo-identification photographs were taken in conjunction with a measurement of

the distance to the fluke using a Bushnell Yardage 1000 laser range finder. This method allows

fluke width, which can be related to body length, to be determined accurately. Using a

polynomial regression derived from whaling data, total length will be calculated for these 87

encounters.

Sperm whale size also can be measured acoustically from click interpulse intervals. Whenever

possible, recordings were made at the beginning of the dive of each identified individual using

the RHIB acoustic recordings systems.

Several of the groups sighted were thought to be nursery groups, and medium to large calves

were sighted on 6 of the 20 days (4, 8, 11, 12, 17, and 18 June). No calves considered to be

small or newly born were observed.

Codas were heard whenever whales were engaged in social behavior and these were recorded

from the RHIBs as well as from the Gyre. Because of the engine and propeller noise radiated by

the Gyre, codas recordings from the small RHIBs were clearer than those recorded by the

Ecologic hydrophone arrays towed from the larger vessel.

Acoustic Monitoring, Detection, and Tracking

For this cruise, two matched two-hydrophone streamer systems, assembled by Ecologic UK Ltd.,

were the primary survey tool. Each array had hydrophone streamer sections consisting of 2

hydrophone elements (Benthos AQ-4) and respective pre-amplifiers (Magrec) providing 30dB

gain and with a 100Hz low cut filter. These were mounted 3 m apart and housed in a ~10 m long

polyurethane tube and 400 m of strengthened tow cable with a hair fairing sheath to reduce cable

noise. One of these arrays, referred to as the "source array", was equipped with a third element

(Benthos AQ-2000) mounted halfway between the other two. This was used as an active

element, driven by an amplifier from the ship, to allow the relative spacing of the two streamers

to be determined acoustically. The other array, deemed the "linear array", was equipped with a

group of six parallel elements (Benthos AQ-4) with 150-cm spacing between them connected to

one Magrec preamplifier. This experimental configuration should provide some directionality

and increased gain, abeam, to cancel a portion of the ship noise, and this could improve the

ability to detect sperm whales acoustically. However, due to technical difficulties this

configuration was not extensively tested and did not provide promising results.

Each array was also equipped with depth sensors (Keller PA-9SE-50 50bar 4-20mA sensor)

whose readings were displayed on panel meters (Asahi Keiki A5000 display units) installed in

the acoustics lab. These units also were linked to one of the labs' computers by means of a RS232 serial connection. The serial string was read by custom software, developed during the cruise

by Ricardo Antunes, and logged within the acoustic Logger database. The depth readings of the

depth sensors were calibrated using a Time-Depth Recorder (Seabird Electronics Model no. 39),

which was attached to the arrays during a trial deployment.

A tandem hydrophone configuration was chosen because, if towed on identical cable lengths, the

two arrays should stream alongside each other to form a two dimensional directional array

approximately 400 m behind the vessel. It was hoped that this configuration would allow side-toside ambiguity to be resolved without maneuvering the vessel. The two hydrophones also

provided opportunities to explore the use of long baseline linear configurations and of course

provided backup if required.
26

The Ecologic hydrophones were deployed at their maximum cable length. As several turns had

to remain on the cable winch drum, the streamers towed approximately 390 m astern of the

vessel. Hydrophone depth depends on tow speed and cable length. With all the cable deployed

the hydrophone elements towed at an approximate depth of 35 m at ship speed of 5 knots. Tow

depth increased to > 100 m when the ship slowed to 2-2.5 knots. During surveys the vessel

maintained a speed of 6 knots, which represented a good compromise between reducing noise

and covering ground. The arrays were left deployed during small boat operations including boat

launch and recovery. When trawling with IKMT, which was usually at night, the arrays were

recovered on board.

The primary acoustic monitoring station was established in a dry lab aft of the computer room on

the 01 deck. A team of four acoustic monitoring personnel (monitors) provided 24-hour coverage

for all of the time that the ship was at sea and off the continental shelf. During different phases of

the cruise and depending on the requirements, acoustic monitors either conducted standard

survey monitoring, conducted searches for whales, or assisted in tracking groups and locating

individuals for photo-ID.

The click detection and display program, Rainbow Click, ran continuously during monitoring and

the detection records were stored as computer files. Rainbow Click software was written by

Douglas Gillespie and is made freely available for marine conservation and protection projects

by the International Fund for Animal Welfare. The companion Ishmael program was run

continuously in real-time spectrogram mode and provided valuable assistance in visually

detecting cetacean vocalizations. Ishmael, written by David Mellinger, is also freely available

software with a variety of acoustic detection and display functions.

Hydrophone Search and Survey: When surveying/searching for whales the monitors listened

carefully to the hydrophones using stereo headphones for one minute every 15 minutes, and then

scored and noted levels of seismics noise and cetacean vocalizations in the Logger program.

Monitors listened to a training program on the first day of the cruise and compared the way they

scored sounds among themselves during the cruise to maintain a consistent scoring system. At

other times output from the hydrophone arrays were output on high quality speakers in the

acoustic lab. In addition, 20-second acoustic samples were recorded automatically as .wav files

every two minutes and continuous recordings were made of interesting noises, including

vocalizations from identified cetaceans, click trains from single animals over entire dives, and

coda vocalizations from sperm whale social groups.

Animal Tracking: Once acoustic contacts had been made and come abeam if the vessel was

operating in survey mode, the role of the acoustic team became to track vocalizing whales to

keep the vessel close to them and provide the visual tracking team with information on bearings

to vocalizing animals. Other information of use to the visual team were cases when a particular

whale stopped clicking. This was usually an indication that it had nearly finished its dive and

would soon surface. When whales were encountered at night acoustic monitoring might have to

keep the vessel close to whales for extended periods relying entirely on acoustic cues. To achieve

this, the acoustic team made use of the tandem arrays running Rainbow Click on two different

computers. Rainbow Click calculates bearings to the sound source (whale) from the arrival delay

of clicks between the 2 hydrophone elements of a single array. However, this produces two

possible bearings, one on each side of the array. On this project, Rainbow Click was run

simultaneously on a second monitoring computer to compare time of arrival between the two

rear hydrophones in each streamer. This second display provided information to resolve side-toside bearings, overcoming the limitation associated with the use of only front/back elements.

With practice, monitors were able to match patterns of clicks from particular whales on the two

displays. In this way the acoustics team could, on most occasions, tell the bearing and direction

of sperm whales relative to the array without having the Gyre turn and this significantly

enhanced their localization and tracking ability.
27

Multi-Channel Acoustic Recordings: On several occasions, usually after recovering the RHIBs

and before trawling, 4-channel recordings were made using 2 elements of each array. Several

different array configurations were explored by changing the length of cable of the "linear array".

The objective of these recordings was to gather data to be used for development and

improvement of sperm whale acoustic location methods for tracking and survey using a wide

aperture linear array.

Small Boat Acoustic Monitoring: Each of the RHIB boats carried their own portable acoustic

stations, consisting of a pair of Hi-Tech HTI-96-MIN hydrophones with 30 m of cable, an

amplifier/conditioner box, a Creative Labs Nomad Jukebox3 recorder, and hand-held directional

hydrophone units. On days when the weather was favorable but no whales had been found, one

or more of the RHIBs might be dispatched to listen (see "Use of RHIBs" above). The Gyre is a

relatively noisy vessel, particularly for acoustic research purposes, whereas a stationary RHIB is

a very quiet platform. It was clear that the acoustic range from the RHIBs was much greater than

that from the Gyre.

Acoustically equipped RHIBs also proved to be a most effective method for fine-scale tracking

during extended encounters with groups of whales. Monitoring could be performed away from

the noise of the Gyre, and the small boats could respond and move quickly to localize animals

complimenting the continuous tracking that the Gyre acoustic team could perform.

Acoustic Tracking Preliminary Results: A total of 956 standard one-minute stations were

completed while searching for and tracking whales. Sperm whales were detected at 555 (58%) of

these (Figure 3.1.6). Sperm whales were detected acoustically at or near about 25% of the XBT

and CTD stations. In addition to monitoring for cetacean vocalizations, the presence of

anthropogenic noise 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 environment and

were detected during approximately 30% of the listening stations.

Tissue Collection/Genetic Typing

Because biopsy samples are usually taken as whales fluke up, photo-ID images and biopsy

samples can be taken efficiently and concurrently. Thus, plans were to do biopsy sampling as

much as possible in conjunction with photo-identification work. However, the biopsy work was

curtailed when Dan Engelhaupt transferred to the R/V Ewing on 9 June 2003 to assist with tasks

on the D-tag/CEE SWSS cruise (see Section 3.2).

While Dan Engelhaupt was aboard Gyre from 31 May through 8 June, biopsy sampling

techniques were combined with photo-ID, photogrammetry, and acoustic data to further

understanding of sperm whale social and population structure. A total of thirteen skin samples

were collected during the cruise (Table 3.1.9 and Figure 3.1.7). Nine biopsy samples with 9

matching photo-ID fluke photographs were taken of whales west of 90°W. One biopsy sample

was collected below the dorsal hump of a whale that was logging at the surface. Three samples

of sloughed skin were collected after breaching and socializing events, although no photo-ID

shots were collected for these whales. All tissue samples obtained are expected to provide ample

material for genetic applications. No significantly large males (whales that appear to be sexually

and physically mature based on estimated sizes) were encountered and therefore none were

sampled.

Overall, the combination of fluke biopsy sampling (waiting until a whale 'flukes-up' before

releasing the dart), photo-ID, photogrammetry, and acoustic recordings of sperm whales proved

highly successful. Although fluke sampling is a more difficult method of obtaining a tissue

sample, the amount of accompanying information (e.g., a whale's fluke ID) is well worth the

additional effort. The genetic information for an individual whale can be used each time a whale
28

Figure 3.1.6. Acoustic detections of sperm whales (dots) on SWSS 2003 WSHC cruise

superimposed on the cruise track occupied while towing the hydrophone arrays

(gray line). Contours are shown for the 200, 1000, 2000, and 3000-m isobaths.

Figure 3.1.7. Locations of biopsy samples on SWSS 2003 WSHC cruise. Contours are shown for

the 200, 1000, 2000, and 3000-m isobaths.
29

Table 3.1.9

Tissue Collection/Genetic Typing Samples Collected During SWSS 2003 WSHC Cruise

(The sample number is coded for the date in dd/mm/yy format and the sequence number.)

Sample # Tissue Type Group

#

Approx. #

whales

in the area

Latitude

(°N)

Longitude

(°W)

030602-01 Biopsy 1 8 27.2654 93.8251

030602-02 Sloughed

Skin

1 8 27.3995 93.8852

030602-03 Sloughed

Skin

1 8 27.3995 93.8852

030602-04 Biopsy 1 8 27.3995 93.8852

030603-01 Biopsy 2 6 27.3865 93.8111

030604-01 Biopsy 2 6 27.4119 93.8816

030604-02 Biopsy 2 6 27.4228 93.8422

030604-03 Biopsy 2 6 27.4188 93.8091

030605-02 Biopsy 3 8 27.4551 93.0028

030605-03 Sloughed

Skin

3 8 27.4109 93.9954

030608-01 Biopsy 4 6 27.5267 93.7363

030608-02 Biopsy 4 6 27.5350 93.7133

030608-03 Biopsy 4 6 27.5916 93.7547

is photo-identified in the future. High levels of communication and coordination between the

RHIB's crew, the visual team, the acoustics team, and the Gyre's crew lead to good success.

Midwater Trawling and Plankton Sampling

A 15-foot Isaacs-Kidd Midwater Trawl with a mouth opening of 14.7 m2 was used for oblique

tows to sample depths of 0-400 m, 0-600 m and 0-800 m. A General Oceanics flowmeter was

suspended in the mouth to measure volume of water filtered. A SeaBird Time, Depth, and

Temperature Recorder (TDTR, Model 39) was attached to one of the bridle wires to measure

these parameters at 10 second intervals. Meters of wire out and real time were tabulated every

200 m. This allowed an estimate to be made of the amount of wire out needed to reach the

targeted depths at which whales are thought to be feeding based on data from D-tagged animals

from summer 2002 and from email reports received from R/V Ewing.

Twenty-five tows were made at various locations representative of LCE, cyclone, and adjacent

slope water along the 800-1000-m isobaths (Figure 3.1.8). Calibration data generated with the

first pair of tows allowed the targeted depths to be reached during subsequent tows to within as

little as 5 m and as much as 25 m. Typically the first 200 m of wire would be set at a ship speed

of 3 knots and with the rest set at speeds up to 4 knots. Wire was paid out at 50 m/min to about

1,000 m short of maximum wire out. Then the winch would be slowed to 30m/min. This turns

out to be critical to "get the slack" out of the wire to achieve the desired depth. Sampling time in

the interval of interest was maximized by stopping the winch for 10 minute intervals and

retrieving wire at 30m/min in the interval. When the top of the interval was reached, the ship was

slowed to 3 knots and wire in was increased to 50m/min. One IKMT sample was lost when the
30

PVC cod end came apart on the ninth trawl. After that use of a cod end was stopped, andthe

canvas distal end of the net was tied off instead. Volumes filtered per trawl ranged from 119,000

to 281,000 cubic meters (see Table 3.1.10).

The IKMT collections are rich in groups such as hatchet fishes, myctophids, viperfish, large

decapod crustaceans, and euphausiids. The quick look impression is that medium-size to large

cephalopods are not in high abundance in the IKMT collections, but small specimens in the 1-2

cm size range are likely to be found when these trawl samples are sorted. The most common

medium to large squid in the IKMT collections are histioteuthids and enoploteuthids. The largest

histioteuthid taken in an IKMT trawl (Figure 3.1.9) was about 30 cm long. Larger individuals of

this family are known to be part of the diet of sperm whales based on squid beaks identified from

the stomachs of whales commercially harvested in the 19th and 20th century.

Two of the IKMT samples were sorted at sea into fishes, crustaceans and "everything else". In

the lab, the groups sorted from these two and from all the rest of the trawls will be broken down

into smaller, more taxonomically defined groups, and for each of these groups the wet volume

biomass will be measured as wet displacement volume. Given the recording of the actual

maximum depths of the samples as well as temperature from the SeaBird sensor on the net and

the time spent in each depth interval, these collections represent the most intensive and bestdocumented midwater trawl samples ever collected in the Gulf of Mexico.

In addition, a Multiple Opening-Closing Net and Environmental Sampling System (MOCNESS)

tow was taken. Its nine nets sampled from 0-800 m, with one sample taken from 0-400 m to be

comparable to the 3 shallow IKMTs and one sample taken over each 50 m interval from 400-800

m. So a total of nine samples were collected with that single MOCNESS deployment. The

deeper MOCNESS samples collected very little plankton volume.

Figure 3.1.8. Locations of IKMT collections on SWSS 2003 WSHC cruise. The cruise track is

shown together with contours for the 200, 1000, 2000, and 3000-m isobaths.
31

Table 3.1.10

Summary of IKMT and MOCNESS Tows Taken on SWSS 2003 WSHC Cruise

Tow

No.

Date

(mm/dd/yyyy)

Time In

(UTC)

Total

Time

(Min)

Start

Location

Lat (°N)

Start

Location

Lon (°W)

End

Location

Lat (°N)

End

Location

Lon (°W)

Volume

(m3)

Maximum

Depth

(m)

1 06/01/2003 03:40 158 26.9877 94.4927 27.0915 94.3847 242203 728

2 06/02/2003 03:24 106 27.2960 93.8323 27.2090 93.8190 162357 ND

3 06/03/2003 07:06 86 27.1900 93.8250 27.2638 93.8502 119240 685

4 06/03/2003 03:51 120 27.4445 93.8508 27.3582 93.9118 173180 892

5 06/04/2003 08:11 92 27.3253 93.9412 27.2968 94.0352 137157 698

6 06/04/2003 00:32 137 27.4482 93.8795 27.3947 93.9732 210286 654

7 06/04/2003 03:47 125 27.4005 93.9387 27.4565 93.8452 191531 708

8 06/05/2003 02:45 118 27.3783 92.9163 27.4372 92.0028 177319 728

9 06/06/2003 05:50 154 27.4355 93.0177 27.2060 93.1245 207955 ND

10 06/06/2003 03:03 168 27.3350 91.8153 27.4222 91.8112 240213 750

11 06/08/2003 03:03 154 27.5992 90.8285 27.5080 90.6868 265598 809

12 06/09/2003 06:23 118 27.5072 90.6835 27.5855 90.7860 211325 544

13 06/10/2003 01:59 168 28.2530 89.0648 28.4030 88.9360 249920 723

14 06/11/2003 06:10 138 28.4270 88.8998 28.5458 88.7950 194451 630

15 06/12/2003 02:40 170 28.9167 87.7667 29.0450 87.6667 280877 778

16 06/13/2003 07:05 123 29.0435 87.6658 29.1497 87.6057 197926 602

17 06/13/2003 04:00 125 28.6905 86.9807 28.6113 87.0368 203810 572

18 06/14/2003 06:27 181 28.5917 87.0458 28.5545 87.2262 275536 789

19 06/14/2003 01:40 179 28.3598 86.8562 28.4720 87.0233 277065 815

20 06/14/2003 04:56 142 28.4777 87.0328 28.5550 87.1780 212981 359

21 06/17/2003 03:39 150 28.6250 88.8458 28.5043 88.7650 232812 407

22 06/17/2003 07:22 151 28.4955 88.7235 28.6113 88.8298 239471 778

M 06/18/2003 03:08 127 28.6978 88.7693 28.5875 88.7625 7302 800

23 06/19/2003 01:32 159 27.8243 90.4422 28.6648 90.4155 279050 610

24 06/19/2003 04:34 154 27.6548 90.4230 27.8330 90.4263 261888 722

25 06/20/2003 07:34 126 27.8330 90.4263 27.7367 90.4650 231377 410

M=MOCNESS trawl
32

Figure 3.1.9. Histioteuthid squid (upper panel) and fang-tooth blackfish (bottom panel) from

IKMT collections near 94°W. The white collection bucket lid is 12" (30 cm) in

diameter.
33

 38kHz ADCP Backscatter: A Tool for Tracking Deep Scattering Layers

The 38kHz ADCP provided the ability to track the diel vertical migration of the main deep

scattering layer (DSL). Each evening before the trawl went in, the backscattering data for the

previous 24 hours were plotted as a function of time to give a visualization of the timing for

daytime descent and nighttime ascent of the DSL. Figure 3.1.10 shows one example. On most

days, several distinct layers were seen, suggesting that different organisms have different

biorhythms or use different environmental cues that trigger their diel vertical migration.

Generally the migrating layers began to descend between 30 to 60 minutes before sunrise from

the surface to between 400 and 450 m depths. The main DSL was present at this depth horizon

for most of the daylight hours, and then some of its component organisms ascended to the

surface again from 0 to 60 minutes after sunset. The main DSL averaged deeper than 450 m

when the ship was in clear blue surface water; its daytime depth in Eddy Sargassum was 500-550

m, compared to just 300 m in the DeSoto Canyon cyclone.

The IKMT trawling each night was targeted for depths from 400-600 m and 600-800 m. Since

these two depth zones were sampled in an area of convergence (Eddy Sargassum) as well as in

an area of divergence (DeSoto Canyon cyclone), the trawl collections from these two

hydrographic boundary conditions should include representatives of the deep scattering nonmigrating species that will be correlated with the backscatter intensities in the deep layers.

Figure 3.1.10. Plot of backscatter intensity from the 38 kHz ADCP. It shows the daytime descent

(starts down 6 hr into the record) and evening ascent (back up at end of the record)

of the deep scattering layer in the eastern Gulf of Mexico. This 21 hour record

begins 03:51 UTC on 14 June and ends 01:06 UTC on 15 June. Bottom depth is

shown by the high intensity return at depths >700 m. The bright green zone

between ~5.5-7.5 hrs into the record comes from a low signal-to-noise period

when the ship transited at a speed over ground of more than 6 knots.
34

3.2 D-tag Cruise 2003

The SWSS 2003 D-tag cruise was conducted from 3-24 June 2003 aboard the R/V Maurice

Ewing (cruise EW0303). The Ewing, operated by Lamont-Doherty Earth Observatory (LDEO),

was made available to SWSS by the National Science Foundation. Cruise EW0303 consisted of

two entirely separate legs. The D-tag leg immediately followed an LDEO-project leg during

which calibrated recordings were made of the Ewing airgun arrays under a separate authorization

from NOAA Fisheries to the National Science Foundation/LDEO. The D-tag leg of cruise

EW0303 began out of Gulfport, MS, and ended in Galveston, TX. During 9-22 June 2003, in the

controlled exposure experiment (CEE) portion of the D-tag cruise, the R/V Ewing was joined by

the seismic source vessel M/V Kondor Explorer, made available by the International Association

of Geophysical Contractors (IAGC) and a coalition of industry sponsors. This vessel's cruise also

consisted of two components, associated with the MMS sponsored SWSS and EARS projects.

The EARS buoy component was to calibrate Kondor airguns under a separate authorization. The

SWSS component was in support of the SWSS D-tag/CEE work under NOAA Fisheries permit

981-1707 issued to Dr. Peter Tyack of WHOI. This summary reports on the D-tag/CEE work

only; persons interested in the EARS component should contact MMS for information.

Additional information associated with this cruise is in Section 4.3 (D-tag analyses).

The primary goals of the SWSS 2003 D-tag/CEE study were to conduct controlled exposure

experiments (CEEs) of an industry standard airgun array and to improve the technology used to

conduct CEEs. Each CEE was composed of a pre-tagging period before a D-tag is attached to a

sperm whale, a pre-exposure period after the tag is attached and prior to the onset of the

controlled sound source, an exposure period during which a sound is transmitted in a controlled

fashion to the tagged whales, and a post-exposure period during which the behavior of the animal

is observed after the sound is turned off. Real-time display of information was used extensively

to maneuver the source vessel into the correct geometry for the sound exposure. As part of

conducting CEEs, a secondary goal of the cruise was to characterize the signals received from

the Kondor source array on a calibrated recording device (the LDEO spar buoy and/or D-tags

attached to the spar buoy; this is separate from the work with the bottom-mounted EARS buoys).

In addition to the primary goals related to CEEs of airgun transmissions, baseline data also were

collected in which tagged whales were not deliberately exposed to sounds. Skin samples were

retrieved on seven occassions from the D-tag suction cups after they released from the animal.

These were retained for genetic analysis. On 13 occassions, in approaching and inspecting

whales, photographs of flukes or photogrammetry images were taken. Visual and acoustic

observers on the observation vessel made continuous observations of the behavior of sperm

whales. Surfacing positions and group compositions were recorded, and the locations of fluking

whales were passed to the acoustics team. The acoustics team tracked the bearing to these whales

using passive tracking, and informed the visual team when whales ceased clicking and were

therefore about to surface. The acoustics team also recorded and logged sounds of interest such

as codas, other natural sounds, and seismic transmissions from ongoing activities. Finally,

environmental measurements were made using XBTs, and videotape was taken for an MMS

documentary.

SWSS Principal Investigators (PIs) who participated on this cruise were Mark Johnson (Field

Party Chief), Patrick Miller, Aaron Thode (3-D passive acoustic tracking PI) and, after transfer

from Gyre on 9 June, Dan Engelhaupt (genetic analyses PI). Terry Ketler of Interactive

Educational Network was the PI for the video documentary work. Additionally, Carol Roden of

MMS participated in the cruise aboard the Kondor. Table 3.2.1 lists the D-tag science team

aboard the Ewing and their duties. Table 3.2.2 lists the LDEO science team aboard the Ewing

and their duties. Table 3.2.3 lists the science team and duties aboard the Kondor.
35

Table 3.2.1

The SWSS 2003 D-tag Cruise: D-tag/CEE Science Team on R/V Maurice Ewing

(PI Institutional Affiliations are Given; Other Personnel were Affiliated Through WHOI)

Personnel Description

Dr. Mark Johnson Field Party Chief, tagger, data analysis (WHOI)

Dr. Patrick Miller Tag boat observer, data analysis (U. of St. Andrews, UK)

Alessandro Bocconcelli Tag boat driver, VHF tracking, deck operations

Kenneth Alex Shorter Tag preparation, tag data management

Maria Elena Quero Visual coordinator, data manager

Michela Podesta Visual data recorder, assistant data manager

Valeria Teloni Acoustic coordinator, data manager, GIS display

Matt Grund Acoustic observer, GIS display

Natacha Aguilar de Soto Acoustic observer

Sue Rocca Acoustic observer

Amy Beier Tagging coordinator on flying bridge, tissue handling

Dee Allen Visual/acoustic observer, permit compliance

Todd Pusser Lead visual observer

Irene Brigga* Visual/acoustic observer

Kara Buckstaff Visual/ acoustic observer

Anna Nousek Visual/ acoustic observer

Suzanne Yin* Visual/ acoustic observer

Dan Engelhaupt Playback coordinator, tissue handling (U. of Durham, UK)

* Also served on Kondor as visual observers (separately)

Table 3.2.2

The SWSS 2003 D-tag Cruise: LDEO Science Team on R/V Maurice Ewing

Personnel Description

Dr. John Diebold Field party chief – LDEO calibration work

Chris Leidhold Science officer

Ethan Gold Systems Admininstrator

Emily Chapp Acoustics Technician, helped with D-tag acoustic tracking

The biology team on-board the Ewing and Kondor were listed as co-Investigators of permit 981-

1707 issued to Dr. Peter Tyack by NOAA Fisheries (formerly National Marine Fisheries

Service). The permit specifically authorized the research activities conducted during the cruise,

including approaching whales for tagging, observing whales during focal follows, and exposing

whales to controlled levels of sound. The permit included requirements that no marine mammals

or sea turtles be exposed to sound levels above 180 dB re 1mPa RMS, that every effort be made

to ensure that animals are disturbed as little as possible, and that no activities be conducted that
36

might cause significant harm to whales. To comply with the permit, Dr. Tyack and coinvestigators developed a detailed protocol to mitigate possible harm related to the tagging or

sound-playback activities. The protocol is given in the Appendix to this report. All parties

throughout the cruise followed this protocol closely.

Chronological Summary

The track of the D-tag leg of cruise EW0303 is shown in Figure 3.2.1 (top panel). A summary of

tagging and CEE activities is given in Table 3.2.4. After leaving Gulfport, MS, on the evening of

3 June, the science team spent June 4-8 working on baseline tagging and coda playbacks. During

this period, a D-tag was attached to one whale in the DeSoto Canyon region. Weather was too

rough to attempt a coda playback with this whale. Several of the days had bad weather. There

was no success in attaching a D-tag after multiple approaches on June 8.

On June 9, the Kondor and Ewing rendezvoused and Dan Engelhaupt transferred from Gyre to

Ewing to fill the critical role of playback coordinator. The Kondor was outfitted with a towed

SEAMAP hydrophone array and a team of visual observers to assure that no marine mammal or

sea turtle would be exposed to sound levels above 180 dB re 1mPa RMS, as is specified in the

Tyack permit. Dr. Douglas Nowacek coordinated the Kondor observer team. The Kondor

propulsion system was very noisy on the towed array, but after several iterations the Kondor

team was able to detect sperm whales out to approximately 1.5 km. The much quieter research

vessel Ewing, in contrast, had detection ranges estimated to be greater than 8 km.

On June 9, the EARS buoys were deployed from the Kondor. Calibration of the Kondor sources

was attempted. This calibration was not completed because beaked whales were sighted within

the mitigation range defined by the mitigation protocol (Appendix). The ships then proceeded to

conduct the D-tag/CEE component of the cruise.

June 10-12 were marked by rough weather, making tagging operations difficult. No tags were

deployed on June 10. Tags were deployed on June 11 and 12. However, these were too late in the

day for there to be sufficient daylight to conduct a CEE. Having a tag on the whale allowed the

Ewing and Kondor to conduct a trial "dry-run" of the CEE procedure. The overall CEE process

was streamlined. These tag data also are valuable as baseline/control data in the SWSS data set.

Table 3.2.3

The SWSS 2003 D-tag Cruise: Multi-Purpose Science Team on M/V Kondor Explorer

Personnel Description Institution

Dr. Douglas Nowacek Permit compliance, observation coordinator WHOI

Carol Roden Visual observations for permit compliance MMS

Sandy Sawyer Visual observer IAGC

Craig Douglas Acoustic systems SEAMAP

Dr. Aaron Thode* 3-D tracking of sperm whales SIO

Dr Joal Newcomb, EARS buoy PI and Team Leader NRL

Jim Showalter EARS buoy NRL

Terry Ketler** Documentary filming PI IEN

NRL = Naval Research Laboratory IEN = Interactive Educational Network

* Transferred to Ewing on June 16 ** Worked on Ewing from June 16-22
37

Figure 3.2.1. D-tag cruise track of R/V Maurice Ewing for SWSS 2003 (upper) and locations of

XBT drops (lower). Locations of XBT drops made during the D-tag/CEE leg of

cruise EW0303 are shown at the black stars. Those of the leg immediately

preceeding the D-tag/CEE leg are shown at the gray stars. The 200, 1000, 2000,

and 3000-m isobath contours are shown.
38

Table 3.2.4

Daily Summary of Tagging and CEE Activity During D-tag Cruise

Date with

whales?

# tags

deployed

#

CEEs

Comments

(times are CDT)

June 3 n/a n/a n/a Departure PM from Gulfport

June 4 y 0 n/a Tag-deploy arm repaired

June 5 y 1 n/a 4:50 deployment, bad weather arrives

June 6 y 0 n/a Weather too rough for tagging

June 7 y 0 n/a Weather too rough for tagging

June 8 y 0 n/a Several approaches, whales avoided R2 tag boat

June 9 n 0 n/a Rendezvous with Kondor. Calibration day, halted

due to mitigation

June 10 y 0 0 Tagging was attempted, but it was too rough

June 11 y 1 0 Weather too rough AM to tag, late attachment

allowed only a test-run CEE

June 12 y 1 0 Rough weather until 1630 made CEE impossible

June 13 y 1 1 CEE start delayed due to rough weather, but CEE

was accomplished later in the day

June 14 y 2 1 Poor VHF tracking placement made the CEE

difficult, W. Neptune arrives in delta area

June 15 n 0 0 No whales, calibration trial with spar buoy

June 16 y 2 1 CEE halted during ramp-up due to mitigation, tags

detached from whales just after mitigation call

June 17 n 0 0 No whales all day in MRC

June 18 n 0 0 No whales all day in MRC, rendezvous with Gyre

June 19 y 1 0 Aborted CEE due to nearby ongoing seismics and

inability to VHF track tagged whale

June 20 y 0 0 Whales avoided R2 on over 5 approaches

June 21 y 0 0 Storms and lightning prohibited tagging

June 22 y 2 1 Storms AM. One tag detached before CEE.

CEE was OK, but VHF tracking was again poor.

Kondor departed in PM to EARS buoys

June 23 n 0 n/a Searching for whales during return transit

June 24 n/a - n/a Arrive dock in Galveston

TOTAL 15/20 11

80.5 hrs

7 w/ skin

4/13 4 CEEs (June 13, 14, 16, 22); 16th not to full-array

4 days rough weather AM (June 10, 11, 12, 21);

3 days no whales (June 15, 17, 18),

1 day no tag-out on whale (June 20),

1 day poor VHF + nearby seismics (June 19)

On June 13 a whale was tagged in the morning and the first CEE was conducted later in the day

when visibility conditions improved sufficiently for effective visual mitigation off the Kondor.

On June 14, a second CEE was conducted with two whales tagged. The tags were placed rather

low on these animals, so VHF reception was very intermittent. This made it difficult to direct the

Kondor toward the tagged whales. Nonetheless, loud seismics were heard on the recovered tags.
39

Also on the 14th, an industry vessel, the Western Neptune, began a planned survey across the

1000-m contour off the Mississippi Delta. Its transmissions began about the same time that the

Kondor began its controlled exposure. This timing means that the pre-exposure data on this CEE

is still valid for the CEE data analysis.

To find whales that were less recently exposed to ongoing seismics, the ships moved back to the

Mississippi River Canyon (MRC) where many whales had been followed just days before. By

1400 CDT on June 15, no whales had been found. The LDEO spar buoy was deployed and the

signature of the Kondor array was recorded on that buoy. Conditions were quite good for this

received-level characterization, and the Kondor was driven to within 100 m of the buoy. LDEO

acquired and analyzed over 250 shots from the buoy. A D-tag attached to the buoy also recorded

these sounds. This will be a useful means to ground-truth levels received on whales during

CEEs. The D-tag also showed that the "deep" hydrophone on the buoy was actually at about 150-

m depth rather than the 500-m depth of the cable. A planned second broadside oriented pass at

1000-m range was canceled due to sighting of mesoplodont beaked whales within the mitigation

range defined by the mitigation protocol (Appendix).

The ships continued to move west. Two large animals were found on the morning of June 16.

Both whales were tagged. A CEE was begun, but 15 minutes into the ramp-up, a Kogia and then

a beaked whale were sighted within the mitigation range defined by the mitigation protocol

(Appendix), so the transmission was stopped. The tags detached early from both whales just after

the mitigation stop.

The MRC was searched for whales on June 17 and 18, but with no detections. The ships then

moved east to a group of whales that had been followed by the Gyre. This area had been avoided

because of ongoing seismics from the Western Neptune, but the search areas further to the west

had been exhausted. On June 19, one whale was tagged, but the tag slipped so low that VHF

tracking was impossible. The CEE was aborted because the Kondor could not be directed

adequately to provide a sufficient exposure to the tagged whale in the presence of the ongoing

seismics.

On June 20 multiple whales were approached with no success tagging. June 21 was stormy, and

lightning prohibited tagging. On the last potential day of CEEs, June 22, the team waited out a

long series of storms until the weather broke. Alex Shorter tagged two whales in rapid

succession. Although one tag detached from one of the whales, a CEE was successfully

accomplished with the other. While transiting to Galveston on June 23, the team searched for

whales to the west of the MRC, but made no detections. The final day of work by the Kondor, also on June 23, was at the EARS buoys and was conducted under a separate authorization.

Summary of Data Collection

During EW0303, a total of 11 sperm whales were tagged. The on-animal recording time was

80.5 hours. The new version-2 D-tags provided higher resolution and lower noise sensor and

acoustic sampling. The average deployment duration from the new tags was almost 8 hours

compared to about 4 hours for the older tags. The baseline data set will be useful to describe the

natural behavior of sperm whales in the Gulf of Mexico. As in 2002, both bottom and mid-water

feeding by sperm whales were recorded. Of particular interest this year are the first all-night data

sets te team has recorded. These will help to round-out the understanding of diel behavior of

sperm whales. Data on more extensive shallow dives and social behavior were collected than in

previous years, which will greatly expand the coda data set. The new version of D-tag records

undistorted clicks to 48 kHz. This will improve analyses of the acoustic structure of sperm whale

clicks.

Out of 13 days with the Kondor available for CEEs, nine days had no CEEs (Table 3.2.4) due to

bad weather (4 d), no whales (3 d), no successful tagging (1 d), or poor VHF tracking due to the
40

presence of ongoing industry seismics (1 d). Four CEEs were attempted with 6 whales tagged.

Three were completed with 4 whales tagged. As noted in Table 3.2.4, these CEEs (on June 14,

19, and 20) were conducted on tagged animals that were difficult to track using the VHF signal.

The location of these tagged whales will be deduced by linking click bottom-echoes to

bathymetry, by assessing time-arrival differences of the Kondor array on the tagged whale versus

the Ewing towed array, and through detailed inspection of the movement data recorded by D-tag.

On the fourth (the CEE of June 16), the seismic source did not reach full power due to a

mitigation stop because of sightings of Kogia within the mitigation range defined by the

mitigation protocol (Appendix). These tags also subsequently detached early from the whales,

but their data may be useful to assess immediate responses to ramp-up. Preliminary estimates of

received levels during the accomplished CEEs ranged from 145-155 dB, but the exact levels will

be examined during the data analysis effort.

D-tag recordings will be linked to part of the over 376 hours of high-quality sperm whale

recordings from the SEAMAP array. These recordings include over 850 codas and numerous

sounds with unusual characteristics, such as rapid click trains. Visual observers logged 4,430

fixes on 810 different surfacings of sperm whales, using three BigEyes and two data recorders

for optimum visual tracking when tags were deployed. All this information was integrated and

logged in a real-time GIS display. This display was particularly useful for the tagging and

playback coordinators.

Seven tissue samples were collected on D-tag suction cups. The team collected 13 high-quality

photo-ID shots, of which 3 were D-tagged whales (sw164a, sw167a & sw167b), two were Stagged in SWSS 2002, and 8 were other whales that fluked during approaches for D-tagging. A

total of 6 different satellite-tagged whales were sighted. LDEO staff measured 23 XBT profiles

in support of tag deployments, although 4 were tests or had bad data (Table 3.2.5; Figure 3.2.1,

lower panel).

Aaron Thode recorded roughly 24 hours on an autonomous towed depth-logging recorder

synchronized with the SEAMAP array (see section 3.4). Data were collected from a pass of the

Kondor firing its airguns past the LDEO spar buoy. Terry Ketler obtained footage from both

Kondor and Ewing to use in the video being prepared for MMS.

Tagging Effort

Two different D-tag designs were used in SWSS 2003. Tag type 1 was identical to that used in

SWSS 2002. It was comprised of a D-tag version 1 with 2 GBytes of FLASH memory and 12 bit

audio resolution. Type 1 tags attached to the whale with 2 nitrile rubber suction cups of diameter

95mm. A passive vacuum pump was included in the tag to periodically reinforce the vacuum in

the cups. The tags were programmed to sample audio at 32 kHz and sensors at 48 Hz, giving a

recording time of 12 hours. The audio sensitivity was -153 dB re μPa meaning that a signal with

153 dB re μPa peak pressure would produce a .wav file recording with peak levels of ±1. This is

also the clipping level of the tag, meaning that 153 dB re 1 mPa is the highest peak level after

input filtering. The sensor suite on the tag consists of an accelerometer (3 axis), magnetometer (3

axis), pressure, and temperature.

Type 2 tags comprised a D-tag version 2 with 3.3 GBytes of FLASH memory and 16 bit audio

resolution. These tags were attached with 4 nitrile rubber suction cups in a square arrangement,

each of diameter 60mm. No pumps were included in the design. Audio was sampled at 96 kHz

and the sensitivity was approximately -192 dB re μPa (a clipping threshold of 192 dB re μPa).

Sensor sampling-rate was 50 Hz with the same sensor suite as D-tag Version 1, plus a new

conductivity sensor. The tag uses a loss-less compression scheme, called x3, developed at WHOI

to greatly extend the recording-time x sampling-rate product. With the settings used, a recording

time of about 16 hours was expected. The version 2 D-tag had not been deployed on a wild
41

Table 3.2.5

Location, Date, Time, and Depth of the 15°C Isotherm at XBT Stations

Filename Date

(mm/ dd/yyyy)

Time

(UTC)

Latitude

(°N)

Longitude

(°W)

15°C

depth

(m)

Notes

ew030301.xt5* 05/27/2003 01:28 26.968 -86.777 - 1

ew030302.xt5* 05/27/2003 01:31 26.968 -86.777 - 1

ew03032.xt5* 05/27/2003 01:39 26.967 -86.933 462 4

ew03033.xt5* 05/27/2003 16:58 27.183 -86.733 447 4

ew03034.x7d* 06/02/2003 06:35 29.849 -87.450 - 2

ew0303_4.x7d* 06/02/2003 11:14 29.843 -87.368 - 3

ew0303_5.x7d* 06/02/2003 11:19 29.843 -87.367 - 2

ew0303_6.x7d* 06/02/2003 15:56 28.828 -87.299 - 2

ew0303_7.x7d* 06/02/2003 18:48 29.838 -87.286 - 2

ew0303a1.xt7 06/05/2003 16:54 29.203 -87.024 184 5

ew0303b2.xt7 06/06/2003 13:05 29.150 -87.683 170 -

ew0303b3.xt7 06/06/2003 13:39 29.150 -83.050 - 3

ew0303b4.x7d 06/07/2003 08:42 28.350 -89.117 216 -

ew0303b5.x7d 06/08/2003 12:37 28.325 -89.598 205 -

ew0303_8.x7d 06/09/2003 02:16 28.407 -89.665 206 -

ew0303_9.x7d 06/09/2003 19:59 28.392 -89.621 222 -

ew0303c1.x7d 06/10/2003 00:02 28.342 -89.622 233 -

ew0303c2.x7d 06/11/2003 20:23 28.294 -89.239 297 -

ew0303c3.x7d 06/12/2003 08:03 27.847 -89.906 270 -

ew0303c4.x7d 06/14/2003 08:00 28.210 -89.325 301 -

ew0303c5.x7d 06/15/2003 09:12 28.652 -88.934 242 -

ew0303c6.x7d 06/16/2003 16:18 28.590 -89.042 213 -

ew0303c7.x7d 06/17/2003 08:15 28.365 -89.120 273 -

* Leg of cruise EW0303 that immediately preceded the D-tag/CEE cruise; included

 here to provide near-in-time temperature data in other parts of the Gulf

1. Tests only: no data

2. Shallow profile; never reaches 15°C

3. Bad data, repeated

4. Deep Gulf profile

5. Failed below ~300 m

animal prior to the experiment but had been proven in pressure tank testing at WHOI. The new

attachment method was a variant of a system tested successfully on a captive dolphin in Florida

over winter 2002-3. See Section 4.3 for additional information on the D-tags.
42

Both tag types were delivered using a 46-ft carbon fiber pole cantilever-mounted to the bow of a

RHIB. Two boats were carried on the Ewing for this purpose: the aluminium-hulled R2, owned

by MMS, and the fiberglass Balena, a Novurania brand RHIB owned by WHOI. The R2 had two

135 hp two-stroke Mercury outboard engines and a pair of transom-mounted 24V electric

trolling motors. On the Ewing, the R2 was hung from the starboard-side CTD winch that had an

A-frame. An unfortunate consequence of this was that CTD measurements were logistically

awkward, requiring moving the R2 to the stern of the ship to clear the winch, so none were taken.

The second RHIB carried on the Ewing, the Balena, is maintained at Woods Hole Oceanographic

Institution and carries two counter-rotating 4-stroke Yamaha 110 hp outboard motors. The

Balena was stowed on the B-deck of the Ewing on its trailer and lowered using the port-side

crane. Protruding metal-work on the ship made movement of the Balena delicate especially in

bad weather. However, the crew of the Ewing handled the operation skillfully.

The R2 was deployed on 11 days while the Balena was used on 4 days. The quiet engines of the

Balena made it the boat of choice to approach whales for tagging. However the R2 is a sturdier

boat and was more straight-forward to deploy and so was used whenever the weather was poor.

The R2 engines are noisy but relatively quiet successful approaches were possible using the

electric motors. Unfortunately both the controller and, later, the propellers of these motors failed

during the cruise. The controller was replaced with equipment from the Ewing but the propeller

breakages ultimately rendered the motors unusable. Both outboard motors on the R2 showed

various alarm signals more-or-less continuously throughout the cruise but performed adequately.

Apart from the electric motors, there were no significant failures with either boat.

After an early breakage was repaired by Ewing engineering staff, the tag delivery system worked

well throughout the cruise and was swapped between the R2 and Balena as needed. Crew aboard

the RHIBs was Alex Bocconcelli (driver), Patrick Miller (observer and permit fulfillment), Mark

Johnson and/or Alex Shorter (taggers), and Natacha Aguilar (trainee observer).

In addition to tagging, the RHIB crew took video for photo-identification and sizing of whales.

No fecal samples were found. A total of 11 tags were delivered in 13 good-weather days with

sperm whales. Overall, the whales semed more difficult to approach than in the two previous

years, having a tendency to make repeated shallow dives to avoid the RHIB. As a result, 55

approaches were required to deliver the tags. Because many groups were approached, a larger

number of takes, which in this case are close approaches, were recorded under Tyack's permit.

Table 3.2.6 gives a summary of tag carries. Figure 3.2.2, upper panel, shows a map of

deployment locations.

Both tag designs included a release that vents the suction cups after a programmable time,

usually when the memory on the tag is full. Although tags often released prior to the

programmed time due to poor skin condition or social rubbing, two tag carries (sw165a and b)

were sufficiently long to require active releasing. Despite the smaller number of tag carries this

year as compared to SWSS 2002 (11 this year, 19 last year) the total on-animal time increased

from approximately 64 hours in 2002 to 80 hours this year. As a result, the average tag carry was

7.5 hours this year, improving over previous years. Most long carries were achieved with the

smaller and lower profile type 2 D-tag. Section 4.3 contains additional information on the tags.

On June 15, an experiment was performed to characterize the receive level of the airgun array on

the Kondor. This was attempted in an area free of marine mammals and primarily involved the

Lamont Doherty acoustic telemetry buoy. A type-2 tag was strapped to the deep hydrophone and

set to record at 96 kHz sampling-rate. The tag was recovered from the buoy after the experiment

and the tag data were saved as data-set lw166a. The tag recording will be compared to the signals

recorded by LDEO from the spar buoy to check the calibration of the buoy hydrophone and to
43

Table 3.2.6

Summary of D-tag Deployments for SWSS 2003

Focal

ID

Date

(mm/dd/yyyy)

Time

(UTC)

Latitude

(°N)

Longitude

(°W)

Hours on

Animal

Tag

Type

Sample

Rate (kHz)

sw156a 06/05/2003 15:06 29.217 87.211 4:50 1 32

sw162a 06/11/2003 22:26 28.139 89.419 1:02 2 96

sw163a 06/12/2003 22:54 28.397 89.684 6:45 2 96

sw164a 06/13/2003 14:47 28.334 89.618 13:32 2 96

sw165a 06/14/2003 18:35 28.480 89.054 ~16:30* 2 96

sw165b 06/14/2003 18:38 28.480 89.054 ~16:30* 2 96

sw167a 06/16/2003 20:26 27.720 90.069 ~31 2 96

sw167b 06/16/2003 21:07 27.688 90.094 ~22 2 96

sw170a 06/19/2003 16:35 28.671 89.001 9:50 2 96

sw173a 06/22/2003 19:46 28.643 88.992 0.53 1 32

sw173b 06/22/2003 19:49 28.643 88.992 5:45 1 32

TOTAL: 80.5

* released after recording complete at 16:20

1

 data not yet extracted from malfunctioning tag

2

 no data collected due to battery malfunction

provide a higher frequency characterization of the airgun signal (the Lamont Doherty system has

a bandwidth of about 10 kHz compared to the tag bandwidth of 46 kHz). The tag also provided

valuable information on the depth and movement of the deep hydrophone on the buoy. Because

there was a substantial surface current, the hydrophone did not hang to its full depth of 500 m but

rather trailed behind the surface expression at a depth, determined from the tag, of 150 m.

Seismic Activities Using the M/V Kondor Explorer

The industry coalition contributed the seismic source vessel M/V Kondor Explorer that was used

in the CEE. The towed airgun array on Kondor had 31 airguns of which three were spares

(Figure 3.2.3). The volume of the airguns was 3090 cubic inches. All of the active transmissions

of the Kondor were recorded.

During the SWSS 2003 D-tag/CEE leg of cruise EW0303, there were five seismic shooting

periods: four playbacks for CEE and one calibration of the Kondor array. The total shooting time

was 5.23 hours for the playbacks (1 hour, 2 hours, 14 minutes, and 2 hours) and 3.2 hours for the

calibration. These times include the ramp up. A mitigation protocol was implemented on the

source vessel Kondor and supported by the visual and acoustic teams on board the Ewing. The

seismic shooting locations are shown in Figure 3.2.4.

The starting time of the ramp up for each seismic event (playback or calibration) was

communicated to the acoustic team by the playback coordinator. After this, the acoustics team

continuously monitored the seismic signals arriving on the SEAMAP array towed by the Ewing.

This was implemented simultaneously with the normal sperm whale acoustic passive tracking.

Thus three acousticians were present for data collection. The seismic playbacks were recorded at
44

Figure 3.2.2. Locations of D-tag deployments (upper) and skin samples (lower) superimposed

over the cruise track.
45

Figure 3.2.3. Dimensions of the airgun array towed by the Kondor.

Figure 3.2.4. Source vessel Kondor (red) in relation to the observation vessel Ewing (blue) while

the Kondor airguns were active.
46

a 96kHz sampling rate and the calibration at 48kHz. The sensitivity of the system was adjusted

when necessary to avoid clipping on the recording system, without reducing the sperm whale

tracking capacity.

Frequent samples of the seismic signals were analyzed in real time with the SEAMAP Cetacean

Monitoring System (CMS) to get peak amplitudes (in dB) and peak frequencies. The analysis

was made on the full pulse and also separately on the direct arrival and the first return of the

signal. The results were stored in a database with spatial and temporal references by means of the

software Logger (IFAW). A preliminary calibration of the system was done on the basis of data

provided by SEAMAP, followed by a full calibration of the system CMS-Alesis digital recorder.

The data are still under analysis, but preliminary results indicate maximum received levels

around 150 dB re 1mPa. They also confirm last year's observations on the presence of medium

and high frequencies on the direct arrival, with recorded peak frequencies up to 15 kHz.

Depending on the distance to the seismic source, the analysis of the frequency distribution of the

overall pulse showed results similar to the direct arrival or to the returns.

GIS-based Tactical Display

A new data logging system was used during the SWSS 2003 CEEs. The system required several

new software components to allow central logging of all observation and navigation data, and

also to allow real-time viewing of the data, as it is collected, via an ArcView Geographic

Information System (GIS). This system was created in a collaboration between Woods Hole

Oceanographic Institution and NATO Undersea Research Center.

Primary functions of the GIS Tactical Display were: real-time support to the tagging operations,

coordination during CEE, and fieldwork planning both before and during the cruise. A new

NMEA-based logging and real-time display system was used for the first time during SWSS

2003. The system worked well, after several on-board upgrades.

Two major requirements were achieved: the ability of the tagging and playback coordinators to

always have a direct and up-to-date overview of the situation and an easily accessible work

station for tracks planning and quick-look overviews. Two GIS Tactical Displays, receiving the

same data source, were used in different locations. On the flying bridge the display was used by

the visual team and the tagging and playback coordinators during the daylight operations. In the

acoustic lab the display was used by the acoustic team and for the day-by-day planning.

Data visualized on the map were ship tracks, from both the observation vessel and the seismic

source vessel, the visual sightings plotted as focal follow and survey layers, the acoustic

detections, the number of acoustic contacts (number of sperm whales heard) plotted using the

position of the ship instead of by slots of time. The acoustic categories (e.g., codas and trumpet

or the anthropogenic noise) were plotted in the same way. The location of each tagging attempt

(successful or not, as the first point) and the monitoring effort (visual and acoustic) were plotted

as well. Pre-collected georeferenced data, such as sighting data and oil platform locations or even

satellite images, were easily added to the map.

GIS tracking tool components: An NMEALogTool was written to simultaneously log many

NMEA serial data streams. This tool also was responsible for broadcasting these data to several

real-time GIS systems throughout the ship. This tool logged navigation and observation data

streams continuously from 6/04 through 6/24, with less than 0.05% scheduled down time for

system upgrades and maintenance, and no unexpected down time.

An acoustic tracking entry tool, AcLogger, was created to allow acoustic tracking data entry. The

user interface collected data and converted this data to an NMEA serial stream for logging and

display. A visual sightings entry tool, Visual-MMI, was written to facilitate visual sighting data
47

entry. Data was entered and converted to an NMEA serial data stream, which was suitable for

logging and display.

Finally, a GIS to NMEA interface, NMEA_IF, was implemented to create and update ArcView

shape files, allowing real-time data viewing with the GIS. This tool parses many data strings and

presents the data to ArcView in rich tables. Many of the data fields from the entry tools are

included in these shape files, allowing detailed real-time data inspection. The ESRI ArcMap

(ArcView 8.3) was the software successfully used for desktop geographic mapping and real-time

data visualization.

GIS tracking tool conclusions and suggestions for future improvements: The SWSS 2003 Dtag/CEE cruise demonstrated the feasibility of RF serial modems for transmitting NMEA data.

During playbacks, the position of the M/V Kondor Explorer was plotted in real-time on the GIS

workstations aboard the R/V Ewing. It is possible to display the tag boat position in a similar

way. More importantly, the modem also can provide a data stream in the other direction. So, the

latest sightings and acoustic bearings can be viewed in real-time on the tag boat to more directly

facilitate tagging. Critical elements include a new rugged lightweight map display and a compact

battery powered GPS and RF modem system.

The current system can only stream data over serial cables. Most modern ships are wired with

Ethernet. Some, including the Ewing, even have shipboard wireless networks. Adding a UDP

broadcast capability to NMEALogTool and NMEA_IF facilitates moving GIS displays to

different areas of the ship. One obvious benefit would be providing the ship's bridge with a map

during night-time acoustic tracking. Another benefit would be moving visual workstations

indoors during foul weather, or during radio tracking. One phase of the D-tag tagging effort that

is not plotted in real time, and not logged in a uniform way is RF beacon tracking. A new RF

tracking system is currently in development.

Passive Acoustic Monitoring

The primary objectives of the acoustic team were to support the animal tracking during tagging

operations, provide behavioral observations during CEEs, and conduct passive tracking. The

acoustic monitoring was organized in four-hour shifts providing 24-hour coverage when the

array was deployed, with different efforts between day and night. Of over 445 total hours of

navigation, the acoustic monitoring covered 376 hours, showing the ability of this system and

team of observers to track whales through the night for early morning operations.

In Day Mode (06:00 a.m. to 08:00 p.m. local time), when close and continuous contact with the

visual team is required, detailed tracking of sperm whales with descriptions of dive behavior and

direction changes was performed. In this mode, two operators acted to fill the acoustic data entry

form and manage communication with the flying bridge. In Night Mode (08:00 p.m. to 06:00

a.m. local time), the priority was to follow the animals until daylight. Only one observer was

required. At night, the logging was limited to significant acoustic events such as codas, creaks,

trumpets and slow clicks.

In both modes, a five-minute timeout was set to record sounds such as ship noise, seismic

activities, biological disturbances, or other sounds that might be interfering with the acoustic

monitoring and to estimate the number of sperm whale contacts at that time. This last

information was logged to provide a quick measurement of the presence of animals in the study

area, especially during the night when detailed animal tracking was not performed. Also, the

number of animals clicking at a certain time can be used as one factor to measure simultaneous

diving events to investigate possible synchrony in diving patterns between sperm whales.

The acoustic team comprised five people with an additional part-time observer after June 16. The

shift schedule was organized to always have two people on duty during the day and one during
48

the night. Occasionally, an observer was involved with parallel activities, such as system set up

and tagging, but the number of available people was sufficient for these absences for short

periods.

Two towed arrays were available on board with listening and recording equipment and computer

software for bearing estimation. The SEAMAP array, a four element array with 300 m of tow

cable and a pressure sensor, was used for the entire cruise during all the tracking operations. The

WHOI array was kept as a backup. Deployment was performed mainly by the crew with the ship

winch; this proved to be fast and convenient. The array was recovered on board in cases of nighttime tag recovery or for high-speed transit to new areas. At the beginning of the cruise, an

additional weight of 12 kilos was added in order to increase the depth of the array. This depth

was always shown on the real-time display as the Depth Acquisition Unit. The array depth

ranged between 15 and 60 m, depending on the tow-speed.

The maximum tow-speed for the SEAMAP array was specified at 8 knots. Reasonable levels of

detection range were obtained for towing speeds up to 6 knots. The manufacturer's audioanalysis tool, provided with the SEAMAP array to monitor the array, was the Cetacean

Monitoring Software. This software proved to be less suitable as a click detector compared to

other available software, such as Rainbow Click. The main concern was the presence on the

bearings screen of "echos", sometimes at more than 40 degrees apart from the real source and

mainly with high amplitude levels. This discrepancy caused an over estimation of the number of

acoustic detections in the first few days of the cruise. The problem was solved by using

additional software (AudioMonitor, developed by Walter Zimmer at SACLANTCEN) to

discriminate between "echos" and positive acoustic detections.

A positive innovation for the recording system consisted of the use of a multi-channel hard disk

recorder, the Alesis adatHD24XR. With this recorder it was possible to save sounds as.wav files

directly into hard drives of 120 GB capability. These files were afterwards downloaded and

stored in daily folders into external hard drives. The standard recording mode was fixed at 48

kHz with two channels. But, as soon as the tag was on the animal, the recordings were switched

to 96 kHz for collecting high quality sound cuts. The beginning of each recording session (every

3 hours at 48 kHz and 1.5 hours at 96 kHz) was synchronized with the acoustic data entry time to

the second and a detailed spreadsheet was continuously updated during the fieldwork. A total of

about 520 GB of recordings was collected during this cruise.

A new acoustic data entry form for the real-time passive acoustic monitoring, the AcLogger, was

used on this cruise for the first time. Its design had been based on previous fieldwork experiences

(SWSS 2002 D-tag/CEE and Sirena sea trials) with the aim to support sperm whale tracking

during tagging operations and to collect acoustic behavioral observations. As with the data

coming from the visual observations, all the entries made with AcLogger were automatically

saved to the NMEA Server. Daily directories holding 10-minute files organized the acoustic

logging outputs together with all the other outputs while a few filters were made to extract the

most significant acoustic information.

The entry form consisted of six straightforward Tabs, each one of which worked for a specific

objective. These were the Sperm Whale Tab, the Generic Tab, the Array Tab, the Recorder Tab,

the Effort Tab, and the Note Tab. The use of the AcLogger was organized through two different

levels, based on the operation mode. During the day, when two operators were on watch, the

AcId in the Sperm Whale Tab, which is a numeric code assigned to distinguish single or group of

animals streaming on the screen, also worked to automatically update the History Window. This

window proved to be particularly useful by showing time, type, bearing and side of the first and

of the last commit for each AcId. This helped the acoustic observer to better estimate when an

animal was going to stop clicking and to advise the visual team of an upcoming surfacing or to

monitor the animal movements when diving and to guide the workboat in the right direction.
49

During the night, while not transiting to a new working area, the acoustic effort was concentrated

on staying with a group of animals until the daylight operations. The data logging was actually

limited to significant acoustic events only and to animal counting.

A considerable number of codas and coda exchanges were observed during this cruise. Most of

them were concentrated near the Mississippi Delta area at less then 30 nm from the coast on the

700-m depth contour. From a preliminary review of the acoustic logging outputs, roughly 870

coda events were recorded, with most events containing several individual codas. In particular,

the 4 and 9 equal spaced clicks pattern seemed to be the most frequent codas. Moreover, fast

series of clicks were observed together with codas production. This peculiar vocalization seemed

to be related to surfacing activities. About 250 of these events occur in the recordings and further

analysis is needed to understand their structure and position within sperm whale vocalizations.

Additionally, 551 creak events were logged, 22 slow-click series, and one trumpet.

Visual and VHF Tracking

The Visual Team consisted of 8 people split in two squads of 4 each. The teams alternated on

watch on the Ewing flying bridge from first daylight to dark. Each squad included one recorder,

two observers at 25x150 binoculars (BigEyes) and one observer at 7x50 binoculars (regular

binoculars). As is noted below, three BigEye observers usually worked simultaneously when the

team was with whales. The third BigEye also was placed to cover portions of the water that were

blocked by the other two BigEyes.

Communication between the recorder and observers was done through headset radios. Two

laptop computers were used on the flying bridge for sighting, environmental, effort, and

navigation data logging. A third laptop, running a GIS software, was available for plotting visual

contacts, acoustic contacts, the R/V Ewing track and the M/V Kondor track.

The two laptops ran the old data logging system (Logger 2000) for the first two days of the D-tag

cruise. Once the new system was entirely set up, VisualMMI was connected to the NMEA Data

Logging System and the GIS was the main system for data recording. The new Data Logging

System was designed with tools that were lacking in the previous data logger. For example, it

provided calculated fields for range from both regular binoculars and BigEyes reticules, a

configuration table that allowed setting the calculation from different heights and for different

conversion factors, and different port settings for NMEA coms. The new system allowed the use

of a third machine easily accessible to the tagging coordinator. This was used to coordinate the

visual, acoustic, and tagging teams with the Ewing bridge for maneuvering the vessel in the best

way for tracking sperm whales, independently from data loggers.

Three different operational states for the visual teams were applied throughout the cruise: (a)

searching for whales, (b) tagging operations, and (c) focal follow. When searching for whales,

the personnel positions consisted of the portside BigEyes operator, the starboard BigEyes

operator, the data recorder with naked-eye observations, and the naked-eyes/regular binocular

observer. In this state, visual observers scanned the entire sighting angle of 360 degrees with the

main goal of detecting sperm whale presence. Any other species observed was recorded but no

extra effort, such as leaving the planned route and maneuvering towards the sighting contact, was

dedicated to identify those species or estimate group sizes. During search status, teams followed

a 2hrs on/2hrs off schedule. A 30-minute rotating schedule was used to cycle each team member

between the four personnel postitions on the flying bridge. This schedule helped to prevent

eyestrain and maintain vigilance.

When engaged in tagging operations, the personnel positions were the portside BigEyes operator,

the starboard BigEyes operator, the data recorder, the naked-eyes/regular binocular observer with

permit compliance activities during approaching, and the tagging coordinator. Once the team was

with whale(s) and the weather was acceptable, the tag boat was launched. During this phase the
50

goal of all the effort was to direct the tag boat as close as possible to a potential target whale. The

tag boat was fed both with visual and acoustic information via VHF radio by the tagging

coordinator, who also coordinated ship's operations and maneuvering with the bridge. Data

relative to the range and bearing of sperm whale(s) present in the area was recorded. This

information was crucial during tagging operations to direct the tag boat to a potential target

whale, and during playbacks for positioning the M/V Kondor appropriately. Each time an animal

fluked up (starting a deep dive), the acoustic lab was alerted so the whale could be tracked

underwater by passive acoustics.

Focal follow operations commenced once a whale was tagged or when only one animal was in

the area. The second visual team was notified to go to the flying bridge. The second team was

dedicated to data collection on other sperm whale(s) or on other focal whales in the case where

two tags were deployed.

The tagged whale became the focal whale, and the search watch schedule was abandoned. At

least 6 people were required to cover the different tasks during a focal follow. Three people from

one team were dedicated to the focal whale while three people from the other team were

dedicatedto other sperm whale(s), if any, present in the area. At least one observer was dedicated

to detecting and locating VHF signals from the tagged whale. When two tags were out at the

same time, both visual teams were on watch to cover all tasks required and to double the effort.

On a total of 18 usable trial days (the first day was considered a test and setting up day), about

15.5 were actual working days on the flying bridge for a total of 220.8 hours. Visual effort was

not conducted only during adverse weather conditions. Successful contacts with sperm whales

characterized about 14.5 working days out of 15.5. Sperm whales were visually located for a

total of 810 surfacings, with 4430 fixes made. A summary is given in Table 3.2.7.

Tagging and Playback Coordinator

Critical for tagging and carrying out CEEs are the roles of the Tagging Coordinator and the

Playback Coordinator. The Tagging Coordinator coordinated all the information between the

tagging boat, bridge, acoustic lab, and visual team and communicated with the tag boat and the

Ewing bridge. The Playback Coordinator used the GIS-based display to direct the Kondor to an

appropriate location for controlled-exposure experiments.

The coordination of tagging and playback operations during the WHOI 2003 D-tag cruise was

significantly improved over last year's efforts as a result of the integration of the visual MMI,

acoustic data feed, and the GIS display. This system allowed both coordinators to see real-time

information for sperm whales both above and below the water and to make immediate decisions

regarding the placement of the Ewing, Kondor, and tagging boat accordingly. Overall, the setup

worked extremely well.

The tagging coordinator was able to quickly relay pertinent acoustic and visual information to

the RHIB to maximize the small window of time sperm whales were at the surface between

dives. The direct ship's phone line between acoustics, the bridge, and the tagging coordinator was

a huge benefit as this eliminated the use of the VHF radio to maintain contact with all

departments, thus reducing the amount of chatter the RHIB receives and the background noise

that "steps on" the VHF radio tracking transmitter signal. However, both the RHIB and the

Kondor were linked by VHF radio contact and required additional information once the first tag

was on a whale and a second tagging attempt or a CEE was underway. These remained sources

of "chatter" for the coordinators. Although the modest solution was to warn the trackers before

the coordinators started talking, this is still a valid problem that may require some attention

especially when tags sit low on whales and so do not give out many signals.
51

Table 3.2.7

Summary of Visual Effort During SWSS 2003 D-tag Cruise

(For Physeter macrocephalus only.)

Date

(mm/dd/yyyy)

Visual

Contacts

Total

Fixes

Earliest

Sighting

(CDT)

Latest

Sighting

(CDT)

Effort

(hrs)

06/04/2003 82 288 09:52 20:01 13.00

06/05/2003 88 457 06:02 15:48 13.00

06/06/2003 0 0 - - 2.00

06/07/2003 3 3 13:34 19:54 7.30

06/08/2003 45 45 06:55 17:46 13.75

06/09/2003 20 193 16:00 20:10 13.75

06/10/2003 48 324 06:25 12:59 13.75

06/11/2003 58 389 07:09 19:41 13.75

06/12/2003 58 458 07:40 20:09 13.00

06/13/2003 34 476 07:35 19:57 13.75

06/14/2003 77 309 10:08 19:52 13.75

06/15/2003 3 7 06:38 06:44 13.75

06/16/2003 26 573 06:45 19:28 13.75

06/17/2003 0 0 - - 11.25

06/18/2003 11 61 18:48 19:55 12.75

06/19/2003 83 365 06:27 20:05 11.75

06/20/2003 36 147 06:47 17:59 10.75

06/21/2003 32 93 06:28 12:20 7.00

06/22/2003 106 242 06:43 20:07 9.00

Total 810 4430 ! ! 220.80

The playback operations also went well. The ability to have the Kondor's course and speed

automatically plotted in real time was extremely beneficial as it eliminated the need for a visual

observer to fix an approximate Kondor position. It was also a valuable tool that allowed the

coordinator to alter the course of the Kondor when whales were detected in the mitigation range

defined by the mitigation protocol (Appendix). The use of hand-held radios on the Kondor's

flying bridge seemed problematic with regards to ship-to-ship communication when the two

ships were separated by some distance. A base radio with proper antenna for the flying bridge of

the seismic vessel is recommended for future cruises.

Tissue Collection/Genetic Typing

Tissue sampling during the D-tag cruise was primarily focused on the opportunistic collection of

sloughed skin occasionally found attached to the D-tag suction cups placed on sperm whales

Table 3.2.8 gives a summary of samples collected, and Figure 3.2.2, lower panel, shows a map of

the locations. A total of seven sloughed skin samples from seven D-tagged sperm whales were

collected during the four-week cruise. 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. On two occasions, skin samples were obtained from two
52

Table 3.2.8

Tissue Collection/Genetic Typing Samples Collected During 2003 D-tag Fieldwork

(Sample number code gives the date (yymmdd) followed by the consecutive number for multiple

samples taken on any given day (01 to 02).)

Sample

Number

Tag

Number

Group

Number

Approx. # Whales

in Area

Latitude

(°N)

Longitude

(°W)

03061201 SW163A 1 12 28.397 89.684

03061301 SW164A 2 8 28.334 89.618

03061401 SW165A 3 20 28.480 89.052

03061402 SW165B 3 20 28.480 89.052

03061901 SW170A 4 12 28.671 89.001

03062201 SW173A 5 25 28.643 88.992

03062202 SW173B 5 25 28.643 88.992

members of two groups (group numbers 3 and 5; see Table 3.2.8). In the first of the two

instances, tagged/sampled whales were found in a cluster formation separated by less than 100

meters. In the second instance, the two tagged/sampled whales were separated by less than 200

meters. Degrees of relatedness will be tested between whales found within all sampled clusters

and groups.

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 provide a rich set of information that can be

directly integrated with the dive profiles of D-tagged whales and incorporated into the analysis of

population and social structure. The combination of genetics and 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.

Collection of Received Level Data on Spar-buoy Hydrophones

On 15 June 2003, time was allocated during the SWSS leg of cruise EW0303 for calibration of

the Kondor seismic source used for the CEEs. The calibration device was the spar buoy that was

assembled a few days before the cruise by Spahr Webb of Lamont-Doherty Earth Observatory.

This buoy suspends two hydrophones connected to digitizing and RF telemetry electronics

designed by Spahr Webb and Alan Nance. The RF signal can be recorded, one channel at a time,

on command, aboard the host vessel, in this case Ewing, with one of four different gain settings

and selectable sampling rates up to 25 kHz. In addition to the signal, the RF telemetry includes

positions from an onboard GPS set. The source array of the Kondor consisted of three strings of

10 SSI G guns each, including 7 2-gun clusters and 3 spares. Total volume was 3090 cu. in.,

fired at a nominal 2000 psi.

The Kondor calibration run took place in water about 1000 meters deep over a gentle slope. The

two hydrophones were suspended on cables 18 meters and 500 meters long. Fortunately, one of

WHOI's type 2 D-tags had been tie-wrapped onto the string just above the deep hydrophone. The

depth transducer of the D-tag showed that the "deep" hydrophone was in fact consistently at a

depth of 150 m. This can only be due to drift-induced drag, which is the result of a differential

between motion of the buoy and the deeper waters in which the hydrophone was located. Before
53

the run was begun, drift was determined by the Ewing bridge to be about 2 knots towards the NE

(047o). The initial calibration pass was set to run in this direction.

The first pass was carried out without complications or problems. The source array ramp-up was

recorded as well as the entire pass (Figure 3.2.5, upper panel). Due to the rate of buoy drift, the

pass took longer than planned. As the closest point of approach (CPA) was neared, it became

apparent that there would not be enough time to complete the shooting pattern as planned.

Shortly after CPA, therefore, Kondor began a hooklike turn to the left, in an effort to get into a

position to record some shots with the calibration buoy abeam before darkness halted the

activities for mitigation purposes. This maneuver was just completed when a beaked whale was

sighted. The shooting was stopped for mitigation, and Kondor's airgun array and the spar buoy

were recovered. Although curtailed for mitigation, a few dozen useful shots were recorded

during this side shot pass of the calibration run (Figure 3.2.6, lower panel).
54

Figure 3.2.5.Track of the Kondor and spar buoy during the calibration run on 15 June 2003.

Upper panel: continuous track of the Kondor during the entire run (thin line) and

track of the buoy during the pass in the direction of the drift. Lower panel: the side

shot portion of the calibration. Positions of individual shots recorded aboard Ewing

are shown as dots along the Kondor track; green for ramp-up shots, red for fullarray calibration shots. The corresponding positions of the spar buoy while

recording these shots are similarly shown along the buoy's track.
55

3.3 S-tag Cruise 2003

The S-tag cruise was conducted aboard the R/V Gyre (cruise 03G07) from 26 June through 14

July 2003. The cruise left Galveston, TX, at approximately 2300 CDT on 25 June 2003 and put

into Pascagoula, MS, at approximately 0830 CDT on 14 July 2003, where the science team

disembarked. Gyre returned to Galveston, TX, at approximately noon on 18 July 2003, where

several of the Texas-based science team members completed demobilization of the vessel. Field

work consisted of tagging sperm whales with satellite-tracked radio tags, associated video work,

photo-ID, and biopsy sampling. In addition, surveys for sperm whales were conducted using

passive acoustics and visual observations, samples were collected for habitat characterization,

and videotape was taken for an MMS documentary. SWSS Principal Investigators (PIs) who

participated in this survey were Ann Jochens (Field Party Chief), Bruce Mate (Tag Team

Leader), and Dan Engelhaupt (Biopsy). Terry Ketler of Interactive Educational Network was the

PI for the video documentary work. These PIs and their supporting teams, together with Bill

Lang and Sarah Tsoflias of MMS, constituted a 25-person science party (Table 3.3.1). Additional

information associated with this cruise is in Sections 4.1 (S-tag analyses), 4.2 (genetic analyses),

4.6 (habitat characterization: eddy-forced variations), and 4.7 (habitat characterization: currents).

During the cruise, 15 sperm whales were tagged and 15 biopsy/skin samples were obtained. The

cruise team searched for sperm whales both acoustically and visually when conditions allowed.

In water depths greater than approximately 700 m, where sperm whales might be encountered,

acoustic "observers" monitored for vocalizing (diving) sperm whales for over 260 hours using

two towed Ecologic hydrophone arrays. Visual observers searched the sea surface with BigEye

binoculars for over 130 hours (generally between 06:30 and 20:30 CDT each day) to locate

sperm whales that were at the surface. Two rigid-hulled inflatable boats (RHIBs) were used:

RHIB-1 for tagging (OSU tag boat Puffin) and RHIB-2 (R2 RHIB) for support and photoidentification. Additionally, 5 CTD stations were made, 48 Deep Blue XBTs provided profiles of

temperature in the upper 760 m, and 75 samples were filtered and analyzed for chlorophyll

content. Ocean current velocities in the upper 300 m and upper 900 m were monitored

continuously with hull-mounted 153 kHz and 38 kHz ADCPs. Near-surface water from the ship's

hull depth of 3.5 m was pumped continuously through SeaBird temperature and conductivity

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

chlorophyll fluorescence once per minute.

The cruise track is shown in Figure 3.3.1. It consisted of three parts. During 26 and 27 June, after

Gyre left Galveston, the ship headed south to 27°20'N, 93°55'W, which was one region

frequented by whales tagged in 2002 where sperm whales also had been observed on the SWSS

2003 WSHC cruise. A meeting was held on 26 June to discuss small boat operations, fueling

protocols, and safety. Shortly before arriving at the first station, the two hydrophone arrays were

deployed, and a CTD cast was made. Due to engine problems that could not be repaired at sea,

the ship returned to port, arriving about 1230 local time on 27 June. Repairs were made and Gyre

headed back out to sea at approximately 1630 local, heading for a way point at 27°30'N,

92°50'W. This was a region with historical and satellite tag observations and where whales also

were observed during the SWSS 2003 WSHC cruise in early June.

On 28 June, the hydrophone arrays were deployed about an hour prior to arrival at the way point.

The visual team commenced observations about 1000 CDT. At about 1940 CDT, two whales

were detected at approximately 27°6'N, 92°40'W, first acoustically, then visually. However, it

was too late to launch small boats. Acoustics stayed with the whales until about 2330 CDT when

acoustic contact ceased. On 29 June, due to bad weather east of 90°W, the search for whales

proceeded in the region bounded by the 26° and 27°N latitude and 92 and 93°W longitude lines.

At about 1600 CDT, the hydrophone arrays were pulled in and a CTD cast was made at

26°57.7'N, 92°48.1'W, before a planned run to the east to get behind the bad weather trough.
56

Table 3.3.1

Science Personnel for SWSS 2003 S-tag Cruise Aboard the R/V Gyre

Description Personnel Institution

Field Party Chief Ann E. Jochens (Oceanography team leader) TAMU

Tagging crew Bruce Mate (Tag team leader) OSU

Mary Lou Mate (Video) OSU

Ladd Irvine (Boat driver) OSU

Dan Engelhaupt (Biopsy/genetic typing) U. Durham, UK

Visual Observers Joel Ortega (Team leader) OSU

Elizabeth Zúñiga OSU

Rhoni Lahn OSU

Bill Lang MMS

Laura Opsommer OSU

Andrew Wigton ExxonMobil

Acoustic team Tom Norris (Team leader) OSU

Sarah Tsoflias MMS

Trent Apple OSU

Anurag Kumar OSU

Elizabeth Zele OSU

 Photo-ID crew Dan Lewer (Boat driver/photographer) OSU

Bruce Miller (Photography) OSU

Terry Ketler (Video) IEN

Oceanography Elizabeth Mitchell TAMU

Alicia Salazar TAMU

TAMU Techs Eddie Webb (Electronics Technician) TAMU

Willie Flemings (Electronics Technician) TAMU

Bill Green (Deck Engineer) TAMU

Marty Bohn (Deck Engineer) TAMU

Unfortunately, weather conditions worsened into Tropical Storm Bill, which was centered to the

south and a bit east of the ship (see Figure 3.3.1). It was forecasted to move NNW at 11 knots,

which would have put the ship right in the path of the storm. With high seas predicted within all

of the study area, Gyre headed back into Galveston for safe harbor, with arrival at about 1530

CDT on 30 June 2003. Time in port was used to check out the small boat operations, add

enhancements to the R2 launch system, and make enhancements to computer systems and

communications.
57

Figure 3.3.1. Cruise track for SWSS 2003 S-tag cruise, R/V Gyre 03G07, conducted 26 June – 14 July 2003. The thick part of the track shows the locations of the temperature,

salinity, and fluorescence taken from approximately 3.5 m below the sea surface

and logged approximately once per minute. The three phases of the cruise are

indicated by the numbers 1 (covering the period June 26-27), 2 (June 28-30), and 3

(July 1-14). The tracks for Tropical Storm Bill (29 June-1 July 2003) and Hurricane

Claudette (8-16 July 2003) are shown. The bathymetric contours shown are for the

200, 1000, 2000, and 3000-m isobaths.

The third part of the cruise began on 1 July 2003. Gyre left the dock at about 1800 CDT and

headed for the way point at 28°40'N, 89°00'W to begin the search for sperm whales in the region

of the Mississippi Canyon and off-shelf of the Mississippi River Delta. By 0730 CDT on 3 July,

the way point, which was part of an area off-shelf of the Mississippi River near where sperm

whales had been detected on the SWSS 2003 WSHC and D-tag/CEE cruises, was reached. This

also was an area where, shortly before and during the cruise, several whales tagged in 2002 had

been located through satellite transmissions. The ensuing 11 dayswere spent working with

animals over the slope in the northeastern Gulf. The RHIBs were launched on every day except

13 July, because no whales were seen or heard that day. Thunderstorms and choppy seas were

prevalent. On some days, this weather caused the small boats to be launched later or to be

brought in earlier than planned. Minor repairs were made to the engines of both RHIBs, but

caused tagging downtime of just a few hours, as some repairs were done after the day's work was

completed. Much of the time, sperm whales were found in widely dispersed groups that were

spread out over several kilometers. On multiple occasions, clusters of 2-3 and up to 8 whales

were seen within these larger groups. At least one whale tagged off the delta later was observed

near the canyon. The region that consistently had numerous whales was centered near 28.6°N

89°W.

Tropical Storm Claudette crossed into the Gulf of Mexico from the Caribbean Sea on 11 July

2003, and made landfall southwest of Galveston near Port O'Connor, TX, on 15 July 2003
58

(Figure 3.3.1). This storm generated high seas in the western Gulf and prevented the S-tag cruise

from returning to Galveston, TX, on 16 July. Seas were increasing in the eastern Gulf, making

launch of small boats problematical. As a result, the ship put in earlier than planned on 14 July

and at Pascagoula, MS, rather than Galveston. The science team disembarked, rented vehicles,

and departed variously for New Orleans, Houston, and Galveston and on from there to their final

destinations. Gyre returned to Galveston, TX, about noon on 18 July. Several members of the

Texas-based science team demobilized the ship from the S-tag cruise.

All S-tag, Photo-ID, and Biopsy/Genetic Typing activities were conducted in accordance with

federal permits from the NOAA Fisheries to Bruce Mate of Oregon State University (permit 365-

1440-01) and to Dan Engelhaupt of the University of Durham (permit 909-1465-01).

Oceanographic Habitat

The habitat characterization work was coordinated by Ann Jochens. The sea surface height

(SSH) analyses, provided by Robert Leben of the Colorado Center for Astrodynamics Research,

University of Colorado, supplemented the historical and S-tag sperm whales sighting data that

were used to determine where to go to search for whales. Selected SSH fields for the period of

the S-tag cruise are shown in Figure 3.3.2. During the time when the cruise was in the western

Gulf (26-29 June 2003), there was a weak anticyclonically (clockwise) circulating feature along

27°N and west of 93°W. In the eastern Gulf, the SSH fields showed a large deepwater

anticyclonic Loop Current Eddy (LCE) adjacent to the upper slope off the Mississippi River

(Figure 3.3.2; feature in red-orange). This LCE had been present during the SWSS 2003 WCHC

cruise conducted just prior to the S-tag cruise. Satellite altimeter data indicated this LCE had a

SSH anomaly of greater than 40 cm and that to its north there was an area of cyclonic circulation

(feature in dark blue) where SSH dipped as low as –20 cm. Strong currents of order 3 knots were

generated at the northern periphery of the LCE. During the S-tag cruise, this LCE moved

southward as the cruise progressed, reducing the amount of water that was being pulled off the

shelf into deeper waters. As a result, the S-tag cruise encountered less low salinity, higher

chlorophyll, "green" water than had the WSHC cruise.

The locations, dates, times, and 15°C isotherm depths of the CTD and XBT stations are given in

Table 3.3.2. Figure 3.3.3 shows a map of the locations. Of the five CTDs taken, two were in the

western Gulf and three were in the eastern Gulf. The temperature-salinity profiles for the CTDs

are shown in Figure 3.3.4. All show evidence of entrainment and mixing of water masses in the

upper waters, as indicated by the vertical variability of the T-S profiles in waters warmer than

~20°C. Reflecting the stronger eddy features in the east, the vertical variability is greater in the

eastern profiles than the western profiles. All show the Gulf-wide characteristic tight T-S profile

below about 17°C. The three stations taken in the eastern Gulf were all taken within the cyclonic

circulation feature; none were taken in the LCE. However, CTDs 3 and 4 show the influence of

the LCE, which during the WSHC cruise had been farther up on the slope, in the salinities > 36.6

near the 26 kg·m-3 contour, as is typical of the Subtropical Underwater mass brought into the

Gulf by LCEs. Additionally, CTD 5 shows the influence of shelf water that was drawn off-shelf

by the LCE. This is seen by two effects: the very low (< 30) salinity in the upper 20 m of the

water column and the eroded (~36.4) salinity maximum at about 26 kg·m-3. CTD data were

reviewed by the acoustics team to make sure ship speed was appropriate to keep the hydrophones

below any shallow sound channels, such as was caused by the strong stratification at CTD 5 due

to the low salinity water layer. XBT stations were taken approximately every 10 nm.

Temperature, salinity, and fluorescence from a depth of ~3.5 m were logged once per minute

throughout the cruise. The sample locations are shown in Figure 3.3.1, which gives the cruise

track. The fluorometer was malfunctioning on 10-11 July, so no fluorescence data were collected

for about 24 hours. There also were some periods when prolonged operation in green water lead

to biofouling artifacts on the cuvette, but post-cruise analysis shows that for most of the time
59

Figure 3.3.2. Sea surface height fields for the period 26 June through 13 July 2003 during the

SWSS 2003 S-tag cruise.

spent in the eastern Gulf, the flow-through fluorescence record will be useful for describing

habitat. The locations, dates, and times of the chlorophyll samples are given in Table 3.3.3, with

the map of locations given in Figure 3.3.5. The samples will be used to calibrate the continuous

fluorescence data. ADCP data generally were collected continuously along the track in water

depths of ~15 m or greater for the 150 kHz ADCP and ~35 m or greater for the 38 kHz ADCP.
60

Table 3.3.2

Summary of Hydrographic Stations on SWSS 2003 S-tag Cruise

(XBTs 6, 10, and 23 were bad, so they were Re-Shot as XBTs 7, 11, and 24.)

Description Date Time

(UTC)

Latitude

(°N)

Longitude

(°W)

Water

Depth

(m)

15°C

Depth

(m)

XBT

Probe

Type

CTD 1 06/27/2003 00:32 27.3097 93.9057 851 240

XBT 1 06/28/2003 18:20 27.5030 92.8292 939 167 Deep Blue

XBT 2 06/28/2003 20:08 27.3538 92.7328 975 207 Deep Blue

XBT 3 06/28/2003 21:34 27.1943 92.6758 1106 222 Deep Blue

XBT 4 06/29/2003 08:13 27.2445 92.8363 1101 213 Deep Blue

XBT 5 06/29/2003 12:47 27.3415 92.5442 935 222 Deep Blue

XBT 7 06/29/2003 18:09 27.0193 92.7365 1307 241 Deep Blue

XBT 8 06/29/2003 19:59 26.8800 92.8508 1371 247 Deep Blue

CTD 2 06/29/2002 22:21 26.9617 92.8010 1545 224

XBT 9 07/03/2003 12:09 28.6653 89.0155 727 242 Deep Blue

CTD 3* 07/03/2003 12:40 28.6682 88.9982 750 232

XBT 11 07/05/2003 15:36 28.7015 88.7163 1208 228 Deep Blue

CTD 4 07/06/2003 03:57 28.7338 88.7527 1025 223

XBT 12 07/06/2003 05:43 28.7742 88.5672 1101 231 Deep Blue

XBT 13 07/06/2003 06:46 28.8318 88.3893 937 219 Deep Blue

XBT 14 07/06/2003 08:34 28.8862 88.2070 1334 226 Deep Blue

XBT 15 07/06/2003 09:02 28.9367 88.0192 1565 220 Deep Blue

XBT 16 07/06/2003 10:18 28.9903 87.8385 1549 185 Deep Blue

CTD 5 07/06/2003 11:54 29.0438 87.6760 1607 161

XBT 17 07/06/2003 17:30 29.1583 87.8673 970 200 Deep Blue

XBT 18 07/07/2003 03:08 29.0407 88.0023 960 207 Deep Blue

XBT 19 07/07/2003 04:52 28.9485 88.1628 1090 216 Deep Blue

XBT 20 07/07/2003 19:22 28.6248 88.8513 1102 252 Deep Blue

XBT 21 07/08/2003 06:33 28.5543 89.1272 530 254 Deep Blue

XBT 22 07/08/2003 09:09 28.6662 89.0037 600 243 Deep Blue

XBT 24 07/08/2003 10:22 28.7405 88.9937 560 200 Deep Blue

XBT 25 07/08/2003 13:25 28.6253 88.8533 1098 265 Deep Blue

XBT 26 07/09/2003 05:03 28.6498 89.0005 744 248 Deep Blue

XBT 27 07/09/2003 07:36 28.4453 88.9967 988 236 Deep Blue

XBT 28 07/09/2003 09:12 28.2837 88.9895 1152 227 Deep Blue

XBT 29 07/09/2003 10:23 28.2793 89.1130 1038 221 Deep Blue

XBT 30 07/09/2003 12:29 28.4825 89.0517 960 251 Deep Blue

XBT 31 07/10/2003 04:11 28.2870 89.1087 1016 214 Deep Blue

XBT 32 07/10/2003 05:35 28.3650 89.2192 699 197 Deep Blue

XBT 33 07/10/2003 09:00 28.1600 89.4948 1027 213 Deep Blue

XBT 34 07/11/2003 04:51 28.1313 89.3070 1051 208 Deep Blue

XBT 35 07/11/2003 06:34 28.1193 89.1177 1171 220 Deep Blue

XBT 36 07/11/2003 08:26 28.2825 89.0825 1037 223 Deep Blue

XBT 37 07/11/2003 10:11 28.4493 89.0813 722 215 Deep Blue

XBT 38 07/11/2003 11:55 28.6135 89.0543 547 233 Deep Blue

XBT 39 07/12/2003 03:48 28.9450 88.6280 446 224 Deep Blue

XBT 40 07/12/2003 05:54 28.9627 88.4365 814 237 Deep Blue
61

Table 3.3.2

Summary of Hydrographic Stations on SWSS 2003 S-tag Cruise (continued)

Description Date Time

(UTC)

Latitude

(°N)

Longitude

(°W)

Water

Depth

(m)

15°C

Depth

(m)

XBT

Probe

Type

XBT 41 07/12/2003 07:39 29.0213 88.2528 869 200 Deep Blue

XBT 42 07/13/2003 00:55 29.2098 87.9377 426 205 Deep Blue

XBT 43 07/13/2003 02:35 29.2620 87.7567 439 189 Deep Blue

XBT 44 07/13/2003 04:20 29.3247 87.5790 366 174 Deep Blue

XBT 45 07/13/2003 06:18 29.3340 87.3825 601 206 Deep Blue

XBT 46 07/13/2003 08:00 29.2392 87.2245 777 206 Deep Blue

XBT 47 07/13/2003 09:49 29.0760 87.1875 972 205 Deep Blue

XBT 48 07/13/2003 11:53 28.9047 87.1832 923 208 Deep Blue

XBT 49 07/13/2003 16:33 28.9620 87.2963 1165 241 Deep Blue

XBT 50 07/13/2003 18:20 29.0895 87.3845 1338 237 Deep Blue

XBT 51 07/13/2003 19:57 29.2178 87.4625 1093 216 Deep Blue

*CTD 3 was taken 0.92 nm from XBT 9 to allow comparison of Deep Blue XBTs with CTD.

Figure 3.3.3. Locations of XBT (crosses) and CTD (circles) stations, superimposed on the cruise

track (gray line), taken during SWSS 2003 S-tag cruise.
62

Figure 3.3.4. Potential temperature-salinity diagrams for the five CTD stations taken during the

SWSS 2003 S-tag cruise. Contours of potential density anomaly (sq) in kg·m-3 also

are shown.

Table 3.3.3

Chlorophyll Stations for the SWSS 2003 S-tag Cruise

Date Time

(UTC)

Nearest

Station

Latitude

(°N)

Longitude

(°W)

06/26/2003 22:55 27.3776 93.9371

06/27/2003 00:14 CTD 1 27.3116 93.9080

06/28/2003 18:35 XBT 1 27.4926 92.8189

06/28/2003 21:43 XBT 3 27.1835 92.6714

06/29/2003 08:13 XBT 4 27.2446 92.8365

06/29/2003 12:47 XBT 5 27.3416 92.5441

06/29/2003 18:02 XBT 7 27.0292 92.7281

06/29/2003 19:57 XBT 8 26.8762 92.8478

07/2/2003 12:08 28.8649 92.0990

07/2/2003 19:04 28.6001 91.7475

07/2/2003 23:00 28.5619 91.1324

07/3/2003 02:56 28.6052 90.4868

07/3/2003 07:02 28.6228 89.8549

07/3/2003 12:20 CTD 3 28.6661 89.0043
63

Table 3.3.3

Chlorophyll Stations for the SWSS 2003 S-tag Cruise (continued)

Date Time

(UTC)

Nearest

Station

Latitude

(°N)

Longitude

(°W)

07/3/2003 17:09 28.5990 89.1096

07/4/2003 20:08 28.6268 88.9820

07/4/2003 21:57 28.6347 88.9379

07/5/2003 00:10 28.5917 88.9221

07/5/2003 05:06 28.6434 88.7703

07/5/2003 08:58 28.8040 88.6336

07/5/2003 13:17 28.6676 88.6774

07/5/2003 14:23 XBT 11 28.7022 88.6669

07/5/2003 17:01 28.7480 88.7663

07/5/2003 18:56 28.6997 88.7704

07/5/2003 20:51 28.6357 88.7419

07/6/2003 00:58 28.7234 88.7541

07/6/2003 03:38 CTD 4 28.7319 88.7568

07/6/2003 06:49 XBT 13 28.8340 88.3817

07/6/2003 07:54 XBT 14 28.8871 88.2039

07/6/2003 09:03 XBT 15 28.9373 88.0172

07/6/2003 10:18 XBT 16 28.9907 87.8354

07/6/2003 11:32 CTD 5 29.0448 87.6772

07/6/2003 19:33 29.1649 87.8971

07/6/2003 23:06 29.1369 88.0017

07/7/2003 03:06 XBT 18 29.0422 88.0012

07/7/2003 04:47 XBT 19 28.9499 88.1551

07/7/2003 17:14 28.6326 88.9187

07/7/2003 19:19 XBT 20 28.6247 88.8494

07/8/2003 01:33 28.7079 88.8290

07/8/2003 06:33 XBT 21 28.5539 89.1280

07/8/2003 09:10 XBT 22 28.6673 89.0028

07/8/2003 10:19 XBT 24 28.7497 88.9913

07/8/2003 13:36 XBT 25 28.6173 88.8522

07/8/2003 17:21 28.5757 88.9203

07/8/2003 23:28 28.6510 88.9397

07/9/2003 05:06 XBT 26 28.6506 89.0032

07/9/2003 07:43 XBT 27 28.4319 88.9963

07/9/2003 09:12 XBT 28 28.2822 88.9894

07/9/2003 10:23 XBT 29 28.2794 89.1137

07/9/2003 12:29 XBT 30 28.4831 89.0515

07/9/2003 18:12 28.5319 88.9620

07/9/2003 22:28 28.6865 89.0456

07/10/2003 05:35 XBT 32 28.3653 89.2196

07/10/2003 09:00 XBT 33 28.1599 89.4951

07/10/2003 17:03 28.2570 89.7364

07/11/2003 04:39 28.1311 89.3306

07/11/2003 06:35 XBT 35 28.1195 89.1158

07/11/2003 08:26 XBT 36 28.2848 89.0827

07/11/2003 11:55 XBT 38 28.6137 89.0542
64

Table 3.3.3

Chlorophyll Stations for the SWSS 2003 S-tag Cruise (continued)

Date Time

(UTC)

Nearest

Station

Latitude

(°N)

Longitude

(°W)

07/11/2003 19:13 28.7379 88.7207

07/11/2003 23:06 28.7901 88.6878

07/12/2003 03:05 28.9094 88.6618

07/12/2003 03:49 XBT 39 28.9422 88.6241

07/12/2003 06:08 XBT 40 28.9725 88.4095

07/12/2003 08:03 XBT 41 29.0351 88.2077

07/12/2003 17:11 28.8508 88.2534

07/12/2003 21:11 29.0191 88.2147

07/13/2003 01:02 XBT 42 29.2140 87.9210

07/13/2003 02:26 XBT 43 29.2576 87.7724

07/13/2003 04:23 XBT 44 29.3269 87.5723

07/13/2003 06:18 XBT 45 29.3341 87.3808

07/13/2003 08:00 XBT 46 29.2387 87.2236

07/13/2003 09:49 XBT 47 29.0743 87.1875

07/13/2003 11:53 XBT 48 28.9030 87.1830

07/13/2003 18:03 29.0700 87.3719

Figure 3.3.5. Cruise track (gray line) and locations of chlorophyll stations (circles) taken during

the SWSS 2003 S-tag cruise.
65

Visual Monitoring

The visual observation team consisted of six people and was coordinated by Joel G. OrtegaOrtiz. During survey/search mode, at least three observers were on watch during daylight hours

from the Gyre's flying bridge. Two observers used BigEye 25x150 binoculars, while a third

observer kept watch with naked eye or 7x50 binoculars and entered data into the computer. The

observers on the BigEye binoculars searched a 100 swath, from 90 (abeam) to 10 past the bow

on the opposite side. Observers rotated positions every 30 minutes. The six observers worked

1.5-hr shifts followed by a 1.5-hr rest period. This schedule was used to minimize observer

fatigue and yet ensure continuity of whale tracking. The range to each sighting was estimated

using reticles etched into the right eyepiece of the binoculars, and horizontal bearings were

measured using a radial measurement scale at the base of the BigEye yoke. Search effort,

sighting conditions, and cetacean sightings were recorded using the computer program Logger.

Logger is a data collection and display program written by Douglas Gillespie and made available

by the International Fund for Animal Welfare.

Once a group of sperm whales was detected, the visual team worked in coordination with the

acoustic team to maximize the effectiveness of S-tagging and photo-ID operations. This involved

plotting the locations of groups of whales in real time using the Logger mapping program, and

monitoring patterns of acoustic detections, movement, and behavior. Locations (or inferred

locations) of animals were communicated by VHF radio to the tagging and photo-ID RHIB boats

to direct them into areas where whales were likely to surface. RHIBs were guided using

software, developed by Joel Ortega at OSU, that provided bearing and approximate distance to

the whales relative to the RHIB boat. The visual team suggested course and speed changes to the

bridge to keep the Gyre in a position to maintain visual and acoustic coverage of whale groups,

which typically could be spread over several miles.

The visual team searched for sperm whales on all 14 days when the ship was in regions that

might have sperm whales. A total of 130.86 hours were spent by the observers either on survey

effort or tracking whales (Table 3.3.4 and Figure 3.3.6). This effort includes only the time when

the computer was operating on the flying bridge and does not account for the survey watch with

naked eye from the either the bridge or the flying bridge during rain.

A total of 579 sightings of sperm whales were recorded (Figure 3.3.7). However, when the vessel

was in tracking mode, many of those sightings were of the same individual, i.e., re-sights.

Additionally, 40 sightings of other cetacean species were recorded during the cruise (Table 3.3.5

and Figure 3.3.8).

Acoustic Monitoring, Detection, and Tracking

The acoustic team consisted of five people and was coordinated by Thomas Norris. A shift

system was established to provide 24-hr coverage while ensuring that "observer fatigue" did not

impact performance. Thomas Norris and Ricardo Antunes, who was acoustic coordinator for the

SWSS 2003 WSHC cruise, met prior to the cruise in Galveston, TX, on 24 June to review

acoustic equipment and protocols. Sarah Tsoflias, who participated as an acoustic observer on

the WSHC cruise, provided some continuity and overlap in protocols between the two 2003

SWSS cruises on Gyre.

Hardware/Software: The passive acoustics monitoring system consisted of two matched

hydrophone array systems assembled by Ecologic UK Ltd. Each array had sections consisting of

2 hydrophone elements (Benthos AQ-4) and respective pre-amplifiers (Magrec) that provided

30dB of gain and a 100Hz high-pass filter. The elements were positioned 3-m apart, and each

was housed in a polyurethane tube, approximately 10-m long, that was filled with non-toxic oil.

The hydrophone array was attached to 400 m of strengthened tow cable with a hair fairing sheath
66

Table 3.3.4

Visual Survey Effort by Day on the SWSS 2003 S-tag Cruise

Day Hours

26 June 2003 2.82

28 June 2003 10.04

29 June 2003 8.98

3 July 2003 10.30

4 July 2003 1.97

5 July 2003 12.92

6 July 2003 11.53

7 July 2003 9.39

8 July 2003 11.90

9 July 2003 10.96

10 July 2003 12.49

11 July 2003 11.94

12 July 2003 6.00

13 July 2003 9.62

Total 130.86

Figure 3.3.6. SWSS 2003 S-tag cruise track with the track during the visual survey effort (thick

black line) superimposed. Contour lines are for the 200, 1000, 2000, and 3000-m

isobaths.
67

Figure 3.3.7. Cruise track line (gray line) and locations of sightings of sperm whales (crosses)

recorded during the SWSS 2003 S-tag cruise. Contour lines show the 200, 1000,

2000, and 3000-m isobaths.

Table 3.3.5

Sightings of Cetaceans Other Than Sperm Whales

Species # Sightings

Pilot whale 6

Pantropical spotted dolphin 5

Kogia sp. 4

Risso's dolphin 1

Rough-toothed dolphin 1

Unidentified dolphin 21

Unidentified whale 2

Unidentified beaked whale 1

Total 40
68

Table 3.3.6

Locations of Sightings of Cetaceans, Other Than Sperm Whales, Recorded During the SWSS

2003 S-tag Cruise

Speices Names Longitude

(°N)

Latitude

(°W)

kogia sp -87.670 29.027

kogia sp -89.723 28.295

kogia sp -88.741 28.675

Pantropical Spotted Dolphin -92.626 27.153

Pantropical Spotted Dolphin -92.824 26.961

Pantropical Spotted Dolphin -88.657 28.673

Pantropical Spotted Dolphin -87.633 29.017

Pantropical Spotted Dolphin -88.881 28.564

Pilot Whale -93.031 27.727

Pilot Whale -89.707 28.289

Pilot Whale -89.687 28.284

Pilot Whale -88.922 28.648

Pilot Whale -88.915 28.648

Pilot Whale -88.721 28.750

Risso's Dolphin -89.020 28.634

Rough-toothed Dolphin -88.107 29.089

Unidentified Beaked Whale -88.683 28.798

Unidentified Dolphin -93.013 27.707

Unidentified Dolphin -92.966 27.658

Unidentified Dolphin -92.889 27.570

Unidentified Dolphin -92.762 26.990

Unidentified Dolphin -87.882 29.163

Unidentified Dolphin -87.882 29.167

Unidentified Dolphin -87.864 29.136

Unidentified Dolphin -88.910 28.587

Unidentified Dolphin -88.936 28.609

Unidentified Dolphin -88.940 28.645

Unidentified Dolphin -89.021 28.504

Unidentified Dolphin -89.693 28.288

Unidentified Dolphin -89.675 28.261

Unidentified Dolphin -89.529 28.363

Unidentified Dolphin -89.509 28.312

Unidentified Dolphin -88.956 28.656

Unidentified Dolphin -88.932 28.650

Unidentified Dolphin -88.737 28.691

Unidentified Dolphin -88.726 28.722

Unidentified Dolphin -87.426 29.156

Unidentified Dolphin -87.446 29.190

Unidentified Whales -87.880 29.141

Unidentified Whales -87.456 29.207
69

Figure 3.3.8. Sightings of cetaceans, other than sperm whales, recorded during the SWSS 2003

S-tag cruise. Shown are (a) Kogia sp.; (b) pantropical spotted dolphin; (c) pilot

whale; (d) Risso's dolphin; (e) rough-toothed dolphin, (f) unidentified beaked

whale; (g) unidentified dolphin; (h) unidentified whales. Contour lines indicate

the 200, 1000, 2000, and 3000-m isobaths.

to reduce cable strumming noise. Each array was equipped with depth sensors (Keller PA-9SE50 50bar 4-20mA sensor). Depth readings were displayed on panel meters (Asahi Keiki A5000

display units) in the acoustics lab. Software for the depth sensors was developed by Ricardo

Antunes on the SWSS 2003 WSHC cruise. Data were logged in the acoustic Logger database.

The dual hydrophone array configuration was used to form a two-dimensional (i.e., in x and y)

array to eliminate the right-left ambiguity that usually results with a single linear array. The

second array also could be used as backup if the primary one failed. The hydrophone arrays were

deployed at their maximum cable length of approximately 375 m. Hydrophone tow depths

depended on tow speed and cable length. With the cable fully deployed, the hydrophone

elements towed at an approximate depth of 35 m at ship speed of 5 knots. Tow depth increased
70

to over 100 m when the ship slowed to 2-2.5 knots. During transit, Gyre typically maintained a

speed of 6-7 knots resulting in a tow depth of 20 m. At this speed, self-generated noise from the

ship and tow-cable often was severe enough to reduce effective detection of sperm whales at

distances greater than ~1 km. Hence, operations were adjusted to provide intensive listening

periods at slower speeds, as described under "Animal Tracking" below.

Each hydrophone array fed into the acoustic acquisition system in the acoustics lab via a deck

cable of the same specifications as the tow cable. The primary acoustic monitoring laboratory

was located in a dry lab aft of the computer room on the 01 deck of the R/V Gyre. The acoustic

acquisition system consisted of an adjustable amplifier/high-pass filter box (Ecologic), an

external USB soundcard (Creative Labs Extigy SB0130), and two desktop computers

independently running signal processing and data-logging software. Output from the

hydrophones could be monitored in real-time using headsets or with high quality speakers in the

acoustic lab. A cross-over and equalizer provided signal conditioning capabilities for real-time

signal monitoring only; this did not affect the signal characteristics of recorded signals.

Signal acquisition, processing and data-logging software consisted of Rainbow Click, Logger,

(written by Douglas Gillespie and available from the International Fund for Animal Welfare),

and Ishmael (written by Dave Mellinger of NOAA/PMEL Newport, Oregon). Rainbow Click

and Ishmael provided real-time signal acquisition, processing, signal display and bearing-tosource calculation capabilities. Logger was used for acoustic, location, and environmental data

acquisition and display as well as providing sperm whale tracking capabilities. All three

programs ran continuously during monitoring. Rainbow Click and Ishmael were used primarily

to monitor hydrophone signals, calculate bearings-to-source (sperm whales), and display

bearing-based tracks of animals. Rainbow Click calculates bearings to the sound source (whale)

from the time-of-arrival delay for individual clicks detected at the two hydrophone elements of a

single linear array. It then displays this on a time-bearing plot using dots with different colors to

represent potentially different animals. Ishmael provides real-time spectrographic display

capabilities as well as the capability to calculate bearings of a common signal from two

hydrophone elements. Logger is designed to automatically record acoustic data (48 kHz sample

rate, based on a user defined sampling schedule), acquired GPS data, and displayed tracks of the

research vessel and bearings to animals. Scored data (e.g., relative loudness of whales and noise,

estimated number of whales detected) were entered manually into Logger. Continuous

recordings also could be made manually (48 kHz sample rate, 2-channels) using Logger. Acoustic data from Logger were written automatically to the hard disk on the computer running

the software. These were later backed up manually on CD's.

Hydrophone Search/Survey: A team of five acoustic personnel (acoustic monitors) provided 24-

hr acoustic monitoring while underway. Acoustic monitoring was conducted during standard

survey mode and searching mode, or when assisting in locating and tracking groups of sperm

whales for tagging purposes. During whale survey and search modes, an acoustic monitor

listened carefully to a pair of hydrophones from one of the linear arrays using stereo headphones

for one minute every 15 minutes. At night, while the vessel was often in transit at a 6-7 knot

speed, an alternative procedure was used, as described under Animal Tracking below. Numbers

of estimated animals, relative loudness of cetacean vocalizations, and relative loudness of

seismic survey and other noise were entered as scores into the Logger program for each listening

station. In addition, during the day every two minutes a 20-second acoustic sample or during the

night a 5 minute sample from every 30 minutes (48 kHz sample rate) was recorded automatically

as .wav files in Logger. Continuous recordings were made in Logger of notable noises, cetacean

vocalization, and other sounds of interest.

Animal Tracking: Once detected, sperm whales were tracked using Rainbow Click and Logger

software. The main purpose of this effort was to provide the visual tracking team and the tagging

team with information on bearings and, when possible, distances to vocalizing sperm whales. To
71

achieve this, the acoustic team made use of the dual hydrophone arrays and software on two

computers. One array and its associated computer station were used to determine horizontal

bearings to the source but with a left/right ambiguity, and the second array and computer station

were used to resolve the left/right ambiguity. After some experience, when all acoustic contacts

were not on the same side of the ship, it often was possible to differentiate which group of sperm

whales was on which side of the ship. In addition, the cessation of clicking for individuals or

groups of sperm whales that were being tracked was noted, and this information passed on to the

visual team. Cessation of clicking usually is an indication that an animal or group of animals

would soon surface. In this way the acoustics team could, on most occasions, tell the bearing

and direction of sperm whales relative to the array without having to turn the ship (as is the case

when using a single array). This method significantly reduced the time required to locate

animals, thus enabling the RHIBs to maneuver into position, in some cases even before animals

were sighted.

Night-time effort was conducted both to survey for sperm whales and to track large groups (> 4-

5 animals) continuously so that the visual and tagging team were able to work with them in the

morning. Night-time surveys frequently consisted of transiting along a predetermined path,

determined by the chief scientists Jochens and Mate, at cruising speeds of 6-7 knots and slowing

at fixed intervals (usually 20 min) to listen for a fixed period (usually 10 minutes). Thus, for

every hour, there were two ten-minute periods that were closely monitored under relatively quiet

self-noise conditions. Detections of sperm whales and other cetaceans were recorded in Logger.

This information was used to determine areas for locating and tracking whales.

Small Boat Acoustic Monitoring: Each of the RHIB boats was outfitted with a hand-held

directional hydrophone unit attached to a pole. Directional hydrophones were used to locate

sperm whales by lowering the unit into the water and rotating the pole to allow the hydrophones

to scan back and forth. Headsets allowed the operator to aurally determine the direction in which

clicks appeared loudest.

Acoustically equipped RHIBs proved to be an effective method for locating and following

groups of sperm whales during extended encounters. Monitoring could be performed away from

the noise of the Gyre, and the small boats could respond and move quickly to localize animals

complementing the continuous tracking of the R/V Gyre acoustic and visual team. RHIBs were

maneuvered to create equilateral triangles that helped to localize the area at which the animals

would surface in order to position the OSU RHIB boat in the best location to deploy tags.

Acoustic Tracking Preliminary Results: Approximately 262 hours of acoustic monitoring and

surveying was completed over 18.5 days or 76% of the time at sea. Several days of effort were

lost due to adverse weather and mechanical problems with the R/V Gyre. These values include

time during transits to and from Galveston and the study areas during which acoustic survey

effort was not undertaken in order to expedite transit times. If the total transit time was excluded,

the percentage of time in which there was acoustic survey effort approaches 100%, i.e., 14 out of

14 days available to conduct effort were monitored acoustically. There were a total of 530 oneminute listening periods of 1 minute listening per every 15 minute during slow transits. Over 350

acoustic contacts of sperm whales were made during these listening periods of which 66% had at

least one acoustic contact. During night-time surveys, a total of 190 ten minute listening periods,

with 10 minutes of intense listening per every 30 minutes, were completed over 8 nights, while

searching for and tracking whales. A histogram of qualitative scores from acoustic listening

periods is given in Figure 3.3.9. A map of acoustic contacts is given in Figure 3.3.10.

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

was noted. The Gyre's own engine and propeller sounds masked many sources of anthropogenic

noise. However, the periodic noise from seismic air-gun surveys were quite common and were

commonly detected during ~30% of the listening periods.
72

Over 200 Rainbow Click files were written automatically by that software on the hard drive.

These files were created by Rainbow Click during signal acquisition and can be used to replay

bearing versus sperm whale click trains in Rainbow Click. "Autorec" files also were written and

saved automatically by Logger during pre-determined sampling periods or manually selected

periods. These acoustic files are formatted as ".wav" files at 24 kHz bandwidth and 2 channels.

However, upon review of the "Autorec" files it was determined that many did not contain useful

signals, e.g., they contained only low amplitude noise. It appears that the default settings in

Logger were changed or defaulted to an incorrect input device (a device other than the Creative

Labs SB Extigy soundcard) before or at some point near the beginning of the cruise. Preliminary

review indicates approximately 187 autorec files with useful audio data were saved.

In addition to these sound files, approximately 240 minutes of 2-channel acoustic recordings

were made to DAT tape, including sperm whale clicks, possible codas, pilot whales, and other

odontocete (mostly delphinid) vocalizations.

Figure 3.3.9. Histogram of qualitative scores from acoustic listening periods.

Frequency histogram of scores 

made during listening periods

0

20

40

60

80

100

120

140

160

1 2 3 4 5 > 5

Value of Score

# of each value

D whistles

D clicks

# of SW's

SW Clicks

# of each value
73

Figure 3.3.10. Acoustic contacts during the SWSS 2003 S-tag cruise.

Satellite-Tracked Tagging

Tagging of sperm whales was supervised by Bruce Mate. The tagging crew departed the R/V

Gyre on RHIB-1 when a group of whales was spotted visually or determined to be close by the

acoustic survey team. Up to five people were on the tagging boat: Ladd Irvine drove, Bruce Mate

tagged, Mary Lou Mate took video of the S-tag attachment, Dan Engelhaupt took biopsies, and

occasionally either Terry Ketler took video for an MMS documentary, Bruce Miller took photoIDs, or Bill Lang observed the research for MMS. The visual and acoustics teams guided the

tagging boat to the area where whales were expected to be surfacing. The acoustics team gave

the tag team clues as to when the whales might surface. Because the first approach of the boat is

often the best, it was important to time the approach well. Care was taken to approach slowly.

Sometimes it was necessary to wait for a subsequent surfacing sequence if RHIB-1 arrived too

late in the surfacing sequence or the initial approach was not successful. Tagging was

accomplished at short range (<3m) using an air-powered tag applicator. Video documentation of

the tagging itself was important to help evaluate placement and penetration. On the first day it

also revealed problems in the application procedure due to humidity; these were subsequently

remedied. A skin biopsy was attempted when feasible after tagging, most often during the same

surfacing and immediately after tagging. Biopsies were obtained from 11 tagged whales.

Underwater video of sperm whales was obtained during two tagging approaches.

Tags were initiated before the cruise to put them into synchrony with the satellite passes and a

fixed duty cycle. Based on the tag results from summer 2001 and summer 2002, an average of 1+

good locations/day was obtained with a 4-hour transmission schedule. Under the 2001 schedule,

the battery supply was used up in 137 days, while some batteries lasted for more than 12 months

in 2002. To increase the likelihood of a year-round picture of movements, tags deployed in 2003

have a 4-hour per day transmission schedule but transmit only one out of every 3 days until the

batteries are exhausted; this is the estimated operation for up to 12!months.
74

Table 3.3.7 shows the date, time, and locations where tags were deployed. Fifteen of eighteen

tags were attached to sperm whales (Figure 3.3.11). As of 23 July 2003, fourteen tags had

transmitted through Argos. Of the 15 whales tagged, three tags were judged "not well attached"

and were not expected to last beyond a few weeks. Two of these tags were poorly attached

because of humidity affecting their attachment to the pushrod system used for tag delivery.

Additionally, 3 tags were lost glancing off of whales. This high rate of missing was due primarily

to operating in rougher-than-ideal sea states.

Table 3.3.7

Locations of Deployments of Sperm Whale Tags During SWSS 2003 S-tag Cruise

PTT

No.

Date

(mm/dd/yyyy)

Time

(UTC)

Latitude

(°N)

Longitude

(°W) Notes

5655 07/03/2003 18:34 28.6467 -88.9979 1

1385 07/03/2003 18:42 28.6510 -89.0005

828 07/03/2003 19:06 28.6572 -89.0091

5654 07/03/2003 19:21 28.6668 -89.0070 2

843 07/05/2003 10:49 28.7250 -88.7211 2

833 07/05/2003 12:41 28.7315 -88.7633

5719 07/05/2003 19:08 28.6980 -88.7648

5720 07/06/2003 18:54 29.1402 -87.9652 2

5647 07/07/2003 10:15 28.6460 -88.9063 1

5710 07/07/2003 15:15 28.6524 -88.9080

839 07/08/2003 14:03 28.5212 -88.9464

848 07/09/2003 11:08 28.5083 -89.0340 1

10820 07/09/2003 11:18 28.5061 -89.0261

829 07/09/2003 18:38 28.4822 -89.0432

5678 07/11/2003 20:17 28.7873 -88.7583

827 07/11/2003 20:43 28.7965 -88.7630

826 07/11/2003 23:10 28.8050 -88.7221

23038 07/11/2003 23:35 28.7940 -88.7242

Notes:

1 - tag lost

2 - attachment not good

Photo-ID, Photogrammetry, and Tag Effects

Photo-ID and photogrammetry work was conducted during good weather by Bruce Miller from

the R2, which was driven by Dan Lewer. The main objective of the photo-ID/photogrammetry

effort during the S-tag cruise was to obtain identification information for the tagged whales. For

this purpose, the photo-ID boat worked in close coordination with the tagging boat. After a

whale was tagged, the tagging boat (RHIB-1) often moved on to look for other whales, leaving

the second boat (R2) responsible for getting pictures of the tag and for identification of the

tagged whale. Concerns developed early in the cruise about whales being sensitive to the R2's

outboard motor noise. As a result, the R2 took a passive role in tagging approaches, spending
75

most of its time 50-100m behind the tagging boat. Later in the cruise, the R2 spent much of its

time helping to identify whale locations underwater by using a hand-held directional

hydrophone. The bearings obtained by the R2 were used in conjunction with the bearings from

the Gyre's array to triangulate a more precise location than either could accomplish without

assistance.

Photos were obtained of all whales tagged in 2003, although all are not suitable for reidentification. Photos also were taken of at least five whales that had been tagged during the

2002 field season. These included one whale that had lost its tag and 4 whales with tags still

attached. All of the tagged whales from 2002 looked like they were in very good condition and

their tags (or tag sites) looked good as well. One tag had nearly worked its way out completely

and had two gooseneck barnacles attached to it. Even this tag site looked very good.

Figure 3.3.11. Locations of the 15 successful tag attachments on the SWSS 2003 S-tag cruise.
76

Tissue Collection/Genetic Typing

Biopsy sampling techniques were combined with satellite-monitored tagging during the second

leg of the Gyre "S-tag cruise" in the northern Gulf of Mexico. Dan Engelhaupt conducted this

work. A total of fifteen skin samples were collected during the cruise (see Table 3.3.8). Eleven

biopsies and one sloughed skin sample were taken of whales tagged with satellite-monitored tags

(Figure 3.3.12). Three biopsy samples were collected from whales tagged with satellitemonitored tags put out in 2002. One of the three 2002 tagged whales that was sampled this year

is believed to be a key member of the female cluster that was tagged and sampled last year and

fills in a very important gap in the data. All tissue samples obtained are expected to provide

ample material for genetic applications. No significantly large males (whales that appear to be

sexually and physically mature based on estimated sizes) were encountered and therefore none

were sampled.

Overall, the combination of satellite-monitored tagging and biopsy sampling was very

successful. A biopsy sample was obtained from multiple members of four groups; several of

these sampled individuals have satellite tags to match. Degrees of relatedness will be tested

between whales found within groups and clusters to study questions on how related and

unrelated whales found within groups and clusters in the northern Gulf of Mexico maintain long

or short term associations over space and time. This year's satellite-monitored tagging and biopsy

sampling success was only achieved through the high levels of communication and coordination

between the RHIB's tagging crew, the visual team, the acoustics team, and the Gyre's crew.

Table 3.3.8

Tissue Collection/Genetic Typing Samples Collected During the SWSS 2003 S-tag Cruise

(Sample number gives date (yymmdd), followed by the consecutive number for multiple samples

taken on any given day [01 to 04])

Sample # S-tag # Tissue Type Group

#

Approx. #

Whales in

Area

Latitude

(°N)

Longitude

(°W)

03070301 5654 or 5655 Biopsy 1 6-12 28.6467 88.9979

03070302 828 Biopsy 1 6-12 28.6572 89.0091

03070501 843 Biopsy 2 7 28.6370 88.7452

03070502 5719 Biopsy 2 7 28.6980 88.7648

03070601 5720 Biopsy 3 6 29.1402 87.9652

03070701 5655* Biopsy 4 12 28.6604 88.9206

03070801 Unknown* Biopsy 4 12 28.6098 88.9377

03070901 Unknown* Biopsy 5 8-10 28.5083 89.0340

03070902 10820 Biopsy 5 8-10 28.5487 88.9961

03070903 829 Biopsy 6 8 28.4822 89.0432

03071001 1385 Biopsy 7 10 28.2684 89.7147

03071101 833 Biopsy 8 7-8 28.6016 88.8991

03071102 5678 Sloughed Skin 9 10 28.7873 88.2583

03071103 827 Biopsy 9 10 28.8050 88.7221

03071104 826 Biopsy 9 10 28.8050 88.7221

 *2002 Tagged Whales
77

Figure 3.3.12. Locations of biopsy samples for whales tagged in 2003 (circles) and 2002

(triangles) and of the sloughed skin sample (cross). All 15 samples were

collected during the SWSS 2003 S-tag cruise.
78

3.4 3-D Passive Acoustic Tracking During D-tag Cruise 2003

Field work for the SWSS 3-D passive acoustic sperm whale tracking project was performed

between June 5 and 24 on the D-tag/CEE cruise. The PI, Aaron Thode, worked off two

platforms: the seismic source vessel M/V Kondor Explorer between June 5 and June 16, and the

R/V Maurice Ewing between June 16 to June 24. The reason for the transfer was that it was

discovered that the engine noise from the Kondor was so intense that it was impossible to

conduct effective passive acoustic monitoring from the vessel. Note that times given in this

section are in local time, which was CDT. Additional information on this study is in Section 4.5.

Two deployments of an autonomous acoustic recorder were made, one each on June 18 and 21.

Both recorded for about 12 hours. The recorder was attached to a rope streaming about 100 m

from the end of the Ewing SEAMAP array. Both recordings were clipped fairly badly due to

what appears to be strum on the tow rope. One of the recordings (June 18) seems to have three

hours of useable data, with at least one set of sperm whale multipaths extracted from the data.

Part 1: Work from the Kondor Explorer

In the original cruise plan, all work for this project was planned to be performed off the Kondor

using two data collection strategies. The first was to time-synch recordings made from the towed

arrays on both the Ewing and Kondor, effectively creating a single large-aperture array with both

ships. The second strategy was to deploy two widely-separated hydrophones from the Kondor.

Between June 4, when the PI boarded the Kondor, and June 8, he worked with Craig Douglas of

SEAMAP Inc. to prepare the SEAMAP hydrophone array for use in the 3-D passive acoustic

tracking expeiments. On June 8 the Kondor departed to rendezvous with the Ewing and to deploy

and possibly calibrate the EARS buoys developed by the Naval Research Laboratory.

The Noise Problem: During June 8, the Kondor acoustics team realized that the noise levels of

the Kondor were limiting the detection range of the SEAMAP array to less than a kilometer. On

June 9, the Kondor was requested to stand off more than 2 nautical miles away from the Ewing

because its ship noise was interfering with the Ewing acoustic detection. On June 10, the noise

levels of the vessel were tested by accelerating the vessel speed to 6 knots through the water,

then freezing both propellers in place. The background noise levels dropped by 30-40 dB. This

proved that cavitation noise was the culprit. Systematic testing of various propeller pitches and

shaft speeds on June 10 and 11 revealed that when only the port engine was used, and if the pitch

of the propeller was set to 1 to 1.5 degrees at a fixed rpm of 200, the background noise levels

could be lowered by about 15 dB while still permitting the Kondor to travel at reasonable speeds.

From opportunistic approaches on different animals the acoustics team estimated detection

ranges of 1-2 km under ideal circumstances from the Kondor. This was adequate to allow

acoustic mitigation monitoring for controlled-exposure experiments, but made impossible the

independent acoustic tracking, which was a fundamental requirement for the 3-D tracking work

described here.

Because of the self-noise issue, the first strategy of coordinating vessel movement to time-synch

recordings became impractical. For example, Kondor would have to get within 1 nautical mile of

Ewing in order to detect the same whale on the arrays of both vessels. This was a difficult

arrangement that also raised the issue of Kondor ship noise interfering with the sperm whale

tracking from the Ewing. So, the first strategy was not pursued.

First Attempts at Deploying Autonomous Recorders: With the possibility of using a second

SEAMAP array eliminated and ship noise issues preventing coordination between the two

vessels, the one avenue remaining was to try and deploy an autonomous flash-memory recorder

off the Kondor in such a way that the horizontal separation between the recorder and the

SEAMAP array was as large as possible. Figure 3.4.1 shows an example of such a recorder.
79

In lieu of using fishing line, 100 m of 5/8" diameter, three-strand polypro rope was attached to

the end of the working SEAMAP array, and then the recorder was attached two meters from the

other end of the rope, weighting the end with a 20 lb shackle (Figure 3.4.2). As the SEAMAP

array itself was 50 m long, the effective aperture of the array could have been as large as 150 m.

This would have permitted tracking of animals out to about the 500-m range. An engineering test

on June 12 showed that this arrangement could work and that the autonomous recorder reached

depths greater than or equal to the SEAMAP array.

The disadvantage of this deployment was that the recorder could not be recovered and replaced

unless the entire towed array itself was recovered. Since the array was needed for mitigation

purposes, the array could be pulled in only early in the morning each day, with the result that a

new configuration could only be tried once a day.

Between June 13 and June 16, as the possibility of transferring to another vessel was considered,

further deployments of the autonomous recorder were made. On the deployment on June 13, the

probe was attached directly to a 5/8" polypro line. The recorder began acquiring data at 20:50

CDT and was recovered at 6:04 CDT on June 14. Data were strongly clipped.

Figure 3.4.1. Example of autonomous flash-memory recorder deployed from Kondor and Ewing.

Figure 3.4.2. Flash memory recorder and depth logger attached at the end of a 100-m polypro

rope. The other end was tied to the end of the SEAMAP array. Note that the

hydrophone is taped to the rope as well. This unfortuantely led to clipping of the

signal.
80

On the experiments of June 15, the probe was re-deployed, but this time with a 5-m long Kevlar

1/4" rope attached to the end of the polypro line with a swivel and with a 4 lb shackle attached to

the other end of the Kevlar rope. The recorder was attached to the Kevlar rope, with the

hydrophone permitted to move freely. The probe was turned on at 20:00 CDT and then recovered

and reset at 7:30 CDT on June 16. Data were found to be unclipped, although a tapping noise

was present.

The June 16 deployment added a radiator hose to cover the entire probe before attaching it to the

Kevlar line. A few brief tests found that the flow noise was cut down further, but resonances

existed in the spectra. These are hypothesized to occur due to "pipe organ" effects from the hose.

These results suggested that the recorder approach could work, provided that the data were

collected on a quieter vessel. The R/V Gyre was in the study area conducting a concurrent

survey. The initial preference of the PI was to transfer to the Gyre, as the passive acoustic team

aboard that vessel were already using two towed arrays, and had expressed interest in working on

the range-depth tracking problem. However, between June 13 and 16 the Gyre was located in

DeSoto Canyon, which was over 100 n.m. to the east of the Ewing position. By the time Gyre

came back west, the Ewing was heading west as well, and it became clear that by the time any

transfer to Gyre would be possible, only 1 or 2 days of data collection might be possible. Thus,

on June 16, during a lull in both tagging and the weather, the PI was transferred to the Ewing, along with his equipment, including the 100 m polypro rope.

Part 2: Work off the Ewing

The main concern about working off the Ewing was that tagging animals is almost always a 24-

hour job, thus limiting the opportunities for pulling the Ewing's SEAMAP array out of the water

and attaching the rope/recorder combination to the array's end. While opportunities for

deployments indeed turned out to be limited, D-tag/CEE Field Party Chief Mark Johnson went

out of his way to try to accommodate the deployment needs for this project.

Other alternate deployment configurations were discussed, including whether the spare WHOImade array on board the Ewing could be deployed in parallel with the SEAMAP array, or

whether the autonomous recorder could be deployed independently from the SEAMAP array

with a long rope. Unfortunately, the WHOI array would not have been able to be deployed deep

enough to be effective without substantial weight being added to the array cable. This would

have required a winch to deploy and retrieve the array. An extra winch was not available, so the

WHOI array could not be used. There was not enough rope available to attempt a parallel

deployment, because about 500 m of rope would have been needed to get adequate separation

between the recorder and the SEAMAP array.

Thus, after discussion with Mark Johnson on how best to deploy a 3-D tracking configuration

with minimum interference to D-tag activities, the PI settled on attaching an acoustic recorder to

the 100 m 5/8" polypro rope to the end of the SEAMAP array, as had been done on the Kondor.

This arrangement provided an excellent deployment geometry for range-depth tracking.

The autonomous recorder data was time-synched with the array data two ways. If whales were

present in the area when the array was deployed, the recorder was activated before attaching it to

the rope, and was time-synched by speaking into the recorder and a handheld VHF radio

simultaneously. The hard-disk recorder for the SEAMAP array recorded the output of the VHF

radio. Thus a single voice would be recorded on both acoustic datasets to permit a crude timesynchronization. If whales were not present, then the recorder was programmed to "wake" and

begin acquiring data at some point in the future, usually 20:00 that same day. A dive watch was

attached next to the probe, with an alarm set to go off at a time shortly after the recorder became
81

active. By correlating the dive watch signal on both the recorder and the array, their data could

be time-synced as well.

Unfortunately, this choice of deployment geometry meant that the times at which the recorder

could be recovered were limited. Between June 16 and June 24, the array was only retrieved

twice, permitting only two chances to collect 12 hour data sets.

The first deployment was June 18. At 14:00 CDT the array was pulled out of the water to enable

a fast transit from one region to another. The recorder was attached and programmed to wake at

20:58. It was decided to try attaching the probe directly to the polypro rope once again, with a

swivel inserted about 7 m in front of the recorder. Unfortunately, this led to clipping of the

signal. The hydrophone also was taped to the rope. This had not been done in previous tests, but

it worsened the clipping problem. The dive watch was programmed to produce an alarm at 21:00

CDT. That evening whales were located and tracking data were collected from 20:00 to 03:00 on

June19. On the morning of the 19th, the D-tag team tagged an animal, but was not able to locate

it until 19:00 in the evening. This prevented the CEE from taking place. To remain with animals

overnight the array was not pulled in. The following morning the array was finally recovered and

the probe retrieved. During June 20 about half of the data were downloaded and it became clear

that portions of the data were heavily clipped by the hydrophone hitting the thick rope.

The second deployment was June 21. The SEAMAP array was retrieved in early afternoon, and a

fresh recorder was attached and programmed to start recording at 20:00 CDT. At 21:00, the array

was pulled in to transit to a different location. It was redeployed at midnight. The recorder was

not retrieved until June 22 at 22:00 CDT. It was found that the recorder had failed when it had

been knocked on the deck at 21:55 on June 21. Thus while a few hours of data were recorded

before 21:55, no sperm whales were present at the time.

Data Available and Lessons Learned

The data obtained from this project consist of multi-channel recordings from the SEAMAP array

during the evenings and early morning of June 16/17, 18/19, and 21/22, as well as autonomous

recorder data collected between 20:00 on June 18 and ending at 3:00 on June 19. A quick

preview of the June 18 set indicates that despite the heavy clipping on the recorder, there are at

least three animals that might be mapped in range and depth using the recorder data. Figure 3.4.3

shows an example of sperm whale data collected on the recorder, and the output of an automated

analysis of the difference in arrival times between the direct path and surface reflections for the

animal visible in the spectrogram. This information is required to obtain the range and depth of

the animal.

In addition, there are indications that the SEAMAP array alone might be able to perform 3-D

tracking at close ranges. Since the array length is 50 m, if animals were approached within 250 m

some range-depth tracking might be possible. An analysis of the June 18 array data shows that

the surface and direct paths can be distinguished quite easily (Figure 3.4.4), which suggests that

enough information may be available to track nearby animals. It will take more analysis to

determine if this is possible.

Several factors led to the sparse data set collected during the experiments conducted here. First,

it was not known how acoustically noisy (above 200 Hz) the Kondor was until it was measured

at sea. This fact alone sacrificed 10 days of sea time. As the Kondor had always been used as a

seismic source vessel and had never used streamers (passive arrays), there had never been an

independent check of the vessel acoustics above a few hundred hertz.

Second, given the relatively short time to prepare for the cruise, it was not possible to fully test

the autonomous recorders before going to sea. As a result methods for handling and attaching the

recorders had to be developed and tested at sea. Trial methods for attaching the recorders led to
82

substantial clipping noise. Additionally, the instruments suffered a few power failures (e.g. July

21) before it was realized that the components inside the recorder pressure case had to be

cushioned more effectively. As the number of deployment opportunities turned out to be limited,

this at-sea learning curve was costly. It is now known that a small-diameter rope (1/4" Kevlar) is

the best choice, and that the recorder hydrophone should not be taped to the rope (e.g. the June

15 data). Finally, a supply of more rope, such as 500 m of 1/4" polypro or Kevlar, would permit

parallel deployments of the recorder and the SEAMAP array.

Figure 3.4.3. Examples of data collected from autonomous recorder on June 18. The upper panel

shows the spectrogram of sperm whale clicks recorded when clipping levels were

low. The lower panel shows the time difference between direct and surface paths

for a sperm whale, extracted automatically from the data.
83

Figure 3.4.4. Plot of arrival angles detected on SEAMAP array, using elements 2 and 3 (11-m

spacing), between 11:30 AM and midnight CDT on 18 June 2003. The fact that the

angles between the direct arrivals and surface reflections can be distinguished

suggests that the array may have collected enough information to estimate range

and depth of certain animals at certain times, along with bearings. However, the

array tilt would need to be estimated.
85

4 TECHNICAL SUMMARY

On 19-21 November 2003, the SWSS Workshop and Planning Meeting was held at the Shell

Westhollow Technology Center in Houston, TX. Attendees were from the scientific community

(SWSS, EARS, AIM, airgun calibration, and other project scientists), the federal government

(including MMS, NSF, ONR, NOAA, and the Marine Mammal Commission), the geophysical

contractor and oil & gas industries, and the SWSS Science Review Board. Science presentations,

made over 1.5 days, provided the background information for use in planning discussions for

SWSS year 3 work and in an exchange of ideas for possible studies beyond SWSS.

Year 3 planning resulted in the recommended work components of

1. S-tag cruise with additional data collection for habitat characterization, biopsy/genetic

analyses, and 3-D passive acoustic tracking,

2. Mesoscale population study cruise from a motorized sailboat with biopsy/genetic

analyses and limited habitat characterization data collection,

3. Enhanced D-tag/Controlled Exposure Experiment data analysis, but no cruise,

4. Data analyses, interpretations, and syntheses by all groups, and

5. Preparation of the synthesis report and data submittal and peer-reviewed publications.

Below are summaries of the SWSS presentations from the workshop; all results are preliminary.

4.1 Status Report on Satellite-Monitored Radio Tag

Dr. Bruce Mate1 and Dr. Joel Ortega-Ortiz1

1

Oregon State University, Hatfield Marine Science Center, Newport, OR 97365

SWSS research with the S-tag portion of the SWSS project is meant to describe broad-scale and

longer-term seasonal movement issues, including the identification of seasonal habitats. In

conjunction with the genetics program, the S-tag portion will also identify any demonstrable

differences in the movements and seasonal habitats of different sex classes.

Some of the 2002 tags, at the time of this report writing, are still reporting data. For the purposes

of this report, data were summarized through 15 October 2003. At that time 3,880 whale tag days

of tracking data had documented 71, 298 kilometers of movements and 878,865 dives.

Because sperm whales have long surfacing times between their feeding dives, we received

sufficient messages to the Argos satellite system to obtain outstanding location class accuracies.

Almost half (44%) of locations were from 0 to 1,000 meters of actual location, and another 27%

were zero class locations. Zero class locations do not have defined accuracies, but in our

laboratory testing, we have found that over 95% of these fall within a range of 11.5!kilometers.

Thus they are used with screening criteria to delete locations which would result in unusually

high swimming speeds, in order to provide additional information about the seasonal

whereabouts of individuals within the Gulf.

In general, animals have moved from DeSoto Canyon in the northeast quadrant of the Gulf along

the slope edge to the Texas/Mexico border, with the bulk of the locations appearing within the

700- to 1,000-meter depth regime. However, several animals have ventured out into water over

3,000!meters deep, visiting the Bay of Campeche and the northwest coast of Cuba. Those

animals venturing over deep water tend to be males. National Marine Fisheries Service surveys

have seen females with calves out in these deepwater regions as well, suggesting the possibility

that there may be both an offshore deepwater stock and a nearshore slope edge population.
86

Because calves have also been seen in the nearshore regions, this does not necessarily suggest an

age-specific segregation pattern (i.e., juveniles vs. adults).

In conjunction with Dan Englehaupt, we are performing analyses of social affiliations over

extended periods of time. In cooperation with Doug Biggs and Ann Jochens, we will conduct

correlations with oceanographic parameters. To date, data confirm that sperm whales are in the

upper Gulf slope region year-round and show that individuals vary in their distance from shore,

depth, speed, and site tenacity. Furthermore, males tend to range more widely, move faster, and

do not necessarily repeat the same seasonal use pattern from year to year.

4.2 Molecular Ecology of Sperm Whales (Physeter macrocephalus) in the Northern Gulf

of Mexico

Dr. Dan Engelhaupt1

1

University of Durham, Department of Biological Sciences, Durham, England

Background

The genetic related aspects for sperm whales occurring in the northern Gulf of Mexico during

SWSS 2003 continued to provide an assessment of how populations and groups are structured, in

addition to providing gender and identification information for whales outfitted with OSU’s

satellite-monitored radio tags (S-tags) and WHOI’s digital sound recording tags (D-tags). Our

component adds essential data required to fully asses 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 some 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. Separating stocks based on geographic boundaries (e.g. northern Gulf of Mexico

and the North Atlantic Ocean stocks) seems illogical given a sperm whale’s enormous potential

for movement. Stocks must be defined using a variety of 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,

2002, and 2003. Samples (including those from S-tagged, D-tagged, opportunistic and stranded

whales) were genotyped using mtDNA and microsatellite techniques. Gender was determined for

nearly all of these samples using molecular sexing techniques.

Population Structure: A comparative analysis of matrilineal mtDNA and biparentally inherited

nuclear genetic markers (microsatellites) continues to show strong population structure for

female lineages between the northern Gulf of Mexico, Mediterranean Sea, and North Atlantic

Ocean stocks. This was expected given previous findings on social and reproductive behavior in

this species. On a global scale, mtDNA variation is low with only 25 haplotypes discovered to

date. In addition to the three most common haplotypes, the Gulf of Mexico population has two

unique haplotypes carried by the majority of sampled whales. Nuclear DNA variation across

oceans appears non-significant suggesting males disperse from their natal groups and spread

their genes to the more philopatric females in different geographic locations.
87

Group Composition: The majority of sampled members from groups were predominately

females, although a few groups appeared to contain only males, suggesting that bachelor groups

may reside in the Gulf. Relatedness levels for individual groups suggest that the group is often

unrelated, although groups did contain first-order relatives (e.g. mother-offspring pairs). Our

continued analyses of the maternally inherited mtDNA control region shows that sperm whale

groups are comprised of both single and multiple matrilines, which combined with the

relatedness levels, may provide additional support to the hypothesis of Whitehead et al. (1991)

that groups are comprised of 'constant companions and casual acquaintances'. Unfortunately, due

to time constraints and other priorities, not all members within the majority of groups were

sampled. However, similar results were found when we examined only those groups where 50%

or more of the estimated group size was sampled.

Genetic Recommendations for SWSS 2004

Genetic techniques supply a powerful set of detailed data that can be directly integrated with

both the movements of satellite-monitored tagged whales and the dive profile data of D-tagged

whales. The gender of a tagged whale may prove crucial towards understanding movement

patterns and dive profile data (i.e., do males and females react differently to anthropogenic noise

influences?). 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. Future

sampling efforts should combine photo-ID and photogrammetry with every biopsy sample in

order to provide estimates of both sexual and physical maturity for males and females located in

the Gulf. This information is crucial towards understanding the relationships among associating

whales and the extent that groups are structured over short and long terms. To increase the

resolution for population structure and trans-oceanic gene flow analyses, sampling efforts should

incorporate sperm whales located in additional geographic areas such as the southern Gulf of

Mexico, Caribbean Sea, western North Atlantic, and Mediterranean Sea. Genetically similar or

different populations may provide us with a means of a "control" group for seismic playbacks

comparisons. Finally, emphasis should be placed on locating and sampling large sexually mature

males found within the northern Gulf. Young calves less than a year old have been seen within

mixed sex groups in the northern Gulf of Mexico, but sightings of large males appear nonexistent. This will most likely require additional cruises in alternative seasons and will assist us

in determining where breeding males might originate and how far they roam. A continuation of

the genetic components previously described will maintain both the quality and quantity of

information required for management purposes.

4.3 Studies Report on SWSS Records with the Digital Sound Recording Tag

Dr. Mark Johnson1, Dr. Peter Tyack1, and Dr. Partrick Miller1

1

Woods Hole Oceanographic Institution, Woods Hole, MA 02543

The WHOI component of the SWSS 2003 program centered on a science cruise on board the

R/V Ewing in June and the ensuing data analysis. The goal of the cruise was to deploy digital

sound recording tags (D-tags) on sperm whales in the northern Gulf of Mexico and then expose

the tagged whales to controlled levels of air-gun sound from an attending seismic survey vessel.

The data set from the cruise includes a range of visual, navigation and shipboard acoustic

observations in addition to the tag data. The objective in analyzing this combined data set is first
88

to develop a baseline model for the behavior of unexposed sperm whales and then to examine the

data taken from exposed animals for significant departures from baseline behavior. Here we

provide an overview of the cruise and some preliminary results together with plans for data

analysis in 2004.

Ewing Cruise

The cruise took place between 3 and 24 of June and made use of two vessels. The R/V Maurice

Ewing, operated by Lamont-Doherty Earth Observatory (LDEO), acted as the observation

platform while a seismic source vessel, the M/V Kondor Explorer, made available by the

International Association of Geophysical Contractors (IAGC) and a coalition of industry

sponsors, provided the controlled sound source. Two small tagging vessels, the R2 and the

Balaena, were operated off the Ewing. The procedure in the 2003 cruise largely followed that of

the successful 2002 cruise on the R/V Gyre. However two new technologies were used in 2003

to overcome limitations found in 2002.

A new tag design, called the DTAG-2, was deployed in 2003. This tag has an extended dynamic

range as compared to DTAG-1, overcoming a clipping limitation with the latter that reduces the

accuracy of received level estimates for loud sounds. The physical size and mounting

arrangement of DTAG-2 are also enhanced to achieve longer attachment times. In practice, both

D-tag designs were used in SWSS 2003. Three DTAG-1 tags were deployed with an average

attachment duration of 3.8 hours, comparable to the average of 4 hours in 2002. In contrast, the 8

DTAG-2 deployments had an average attachment duration of 8.7 hours, a dramatic

improvement. The 3-phase controlled exposure experiment (CEE) design we have developed

requires at least 4 hours with 6 hours being preferred. Clearly the increased longevity of DTAG2 will enable more successful CEE trials. A concern has been raised that the new tag design is

more prone to slide on the body of sperm whales than the older version making VHF tracking

difficult. In fact this is not the case: 4 of 11 tags in 2003 slid down the body of the whale during

deployment resulting in poor placements. Of these 1 of 3 and 3 of 8, respectively, were DTAG1s and DTAG-2s. Poor placements typically resulted from attempting to tag in high swell and the

presence of relatively thin whales, rather than due to a deficiency in the tag design.

A new data logging and real-time GIS display system was used during the 2003 cruise to handle

observation and navigation data collected on the Ewing as well as navigation data sent from the

Kondor via a radio modem. The system was created in a collaboration between WHOI and

NATO Undersea Research Center to address a key need identified in previous cruises: the ability

to display real-time navigation and observation data before and during a CEE in order to direct

the source vessel accurately towards the tagged whale. The system functioned extremely well

and was crucial for planning CEEs in the widespread groups of whales encountered in the 2003

cruise.

Fieldwork in 2003 was conducted under National Marine Fisheries Service (NMFS) permit 981-

1707 issued to Dr. Peter Tyack. The permit included the requirement that no marine mammals or

sea turtles be exposed to sound levels above 180 dB re 1mPa RMS. To comply with the permit,

Dr. Tyack and co-investigators developed a mitigation protocol defining the procedure should

species other than sperm whales be observed during CEEs. Beaked whales were sighted on two

occasions during seismic operations and the mitigation procedure was invoked. Although this

interrupted a calibration experiment, it did not curtail any CEEs: on the one occasion in which a

CEE was abandoned following the mitigation procedure, the tag also released from the whale

prematurely and would not have collected data through a full CEE. A key practical consequence

of the 180dB mitigation radius was that the desired high level (160+dB) CEEs were not possible

when the tagged whale was within a widespread group as was often the case in 2003. As no

whale in the group could be exposed beyond 180dB and the available propagation models for the

air-gun array were conservative, relatively low level CEEs resulted. The full-bandwidth three-
89

dimensional propagation of signals from airgun arrays needs to be better understood and

modeled for CEEs to more closely approach the permitted ceiling of exposures.

Out of 14 days in which the Kondor was available to perform CEEs, we conducted 3 complete

experiments with a total of 4 whales, a similar success rate as in 2002 (the 2002 result was 2

CEEs to 4 whales in 11 days). Of the remaining 11 days, 8 were spent with bad weather or no

whales and on one good-weather day we were unable to tag any of the whales approached. CEEs

were aborted on two occasions, one due to mitigation as described above and the other due to

poor VHF tracking of the tagged whale which was already in the presence of an uncontrolled

seismic survey. One day in which whales were not sighted was used to perform a calibration

experiment on the Kondor seismic array. A key limiting factor in 2003 was the formation of a

large wide-spread group of sperm whales in the northern gulf perhaps in response to a

pronounced eddy. This area coincided with an on-going seismic survey from vessel Neptune.

Based upon our experimental design, to obtain independent samples of CEE response, we need

to move at least 10 miles after each CEE. However, animals were scarce outside of the main

accumulation and considerable time was spent trying to find whales distant from the Neptune.

The added requirement to deploy an EARS buoy, calibrate its location, and use the Kondor to

obtain calibrated measurements of airgun sounds also cost precious days that could otherwise

have been devoted to CEEs. Nonetheless, the cruise was a success in producing high quality

CEE and baseline samples at the same rate as in the 2002 cruise.

Analysis

To date, we have carried out 10 cruises focused on sperm whales in three different sites: the Gulf

of Mexico, Mediterranean, and the north-western Atlantic. The combined database of 275 hours

of tag recordings spanning 230 deep dives is a formidable resource for predicting the natural

behavior of sperm whales. A team of scientists, post-doctoral investigators and engineers at

WHOI will be working with this data in 2004. The analysis process is time-consuming on

account of the density of data collected. Steps include (i) listening to sound recordings and

examining them with spectral analysis tools, (ii) calculating the 3-dimensional whale track from

the tag sensor measurements and ship-board observations, and (iii) assembling sounds and

movements in a common geographic frame. With the results of these low-level analyses, we

work to assemble a model of natural sperm whale behavior encompassing, at present, diving

energetics, foraging methodology, sound source characteristics, and social organization. This

natural model provides a basis with which to compare the behavior of animals during CEEs and

suggests appropriate metrics for comparison. At present, we are working with the following

metrics:

• Horizontal avoidance (change in heading) • Energy investment (change in fluking rate) • Foraging success (change in creak rate) • Behavioral state (cessation of diving, change in foraging style, may include horizontal

or vertical avoidance) • Group dynamics (change in separation)

The 8 tag data sets collected during the 5 CEEs show received levels for the seismic source of

between 145 to 160 dB re 1μPa peak-to-peak, which is equivalent to 130 to 146 dB re 1μPa

RMS. Examination of the data is in a very preliminary stage. However, we offer some early

results here to exemplify how the above metrics can be used to assess response. A key finding

has been that the spectrum of air-gun sounds heard by tagged whales varies enormously and can

include significant high frequency energy (well above 1 kHz) coinciding with the likely range of

maximum hearing sensitivity of sperm whales. Such high-frequency sounds had not previously

been considered likely from air-guns and a production model for these is still lacking. One of our

CEE trials (sw03_173b) has energy from the direct arriving air-gun sound at frequencies up to 12

kHz. This whale remained close to the surface in a resting mode throughout the CEE and began
90

deep diving 10 minutes after the end of the CEE. However, the behavior prior to the CEE was a

mixture of resting and socializing complicating a conclusion of horizontal avoidance. Predictions

of normal durations in these behavioral states from the baseline data set will help to establish the

likelihood of a response.

A second CEE (sw03_165a/b) offers a possible example of horizontal avoidance. In this case,

two tagged whales traveled consistently north-east before and after the CEE but changed heading

to due north during the second (and louder) half of the seismic vessel approach. Both whales

returned to their original track-line following the experiment. The whales performed deep

foraging dives throughout the episode. Although horizontal avoidance appears to be indicated,

we see little indication so far that this was costly in terms of foraging success. Baseline results

concerning the normal variation in creaking and turning rates will help to establish the

probability of a response, and will help in determining whether any such response may have had

an adverse impact. In both CEE examples here, the key requirement is a reliable model for

normal behavior. Our analysis work in 2004 will go a long way towards establishing this and,

along with the CEE trials, will represent a unique and significant research product from the

SWSS project.

4.4 Sperm Whale Abundance, Habitat Use, and Aspects of Social Organization in

the Northern Gulf of Mexico

Dr. Nathalie Jaquet1, Dr. Jonathan Gordon2, and Dr. Bernd Würsig1

1

Texas A&M University, 5007 Ave U, Galveston, TX 77551 USA 2

Sea Mammal Research Unit, Gatty Marine Laboratory, University of Saint Andrews, Saint

Andrews, Fife, Scotland. UK

Introduction

This report describes behavioral/photographic/acoustic findings conducted under the SWSS

umbrella of research. We provide a mark-recapture estimate of population size, habitat

preferences, inter and intra-year site fidelity, small-scale movements, and aspects of social

organization. The findings are to be considered preliminary pending further analyses and

integration with other aspects of the study.

Study Area

Our study area for the 3-week cruise of June 2003 consisted of parts of the continental slope

(~500 m to 1500 m in depth) between 95°W and 86°W (Figure 4.4.1). In the text below, this area

is referred to as the "northern Gulf of Mexico", although it does not encompass the entire

northern Gulf.

Preliminary Results and Discussion

Distribution and habitat preference: Our intention during this survey was to spread our search

effort in a consistent way to cover the entire survey area of the upper slope of the northern Gulf

of Mexico between 95°W to 86°W (Figure 4.4.1). Survey tracks were designed using the

Distance Program (Thomas et al. 1998). The upper slope, from the 500-m contour out to

approximately 10 miles beyond the 1000-m contour, was divided into four boxes. The Distance

Program was used to derive survey tracks to provide an equal level of coverage within the three

eastern boxes, where sperm whale density was expected to be highest, and half that level of

coverage in the western block (Figure 4.4.2 top panel). During daylight hours, sperm whale

groups were followed closely for photo-identification, recording of vocalizations, and behavioral

observations. Therefore, the achieved track (Figure 4.4.2 bottom panel) reflects the high

concentration of whales that we encountered in the central blocks. The vessel’s activity (for

example, predetermined vs. random tracks, etc.) was noted regularly in specially prepared forms
91

Figure 4.4.1. The Gulf of Mexico with study area outlined.

in the Logger Program, as were factors that might affect detectability, such as weather and

underwater noise conditions. This information can be used to extract and interpret those data that

might legitimately be used to assess relative abundance and habitat preferences for sperm

whales. We extracted appropriate data from the 2002 and 2003 habitat characterization/photoidentification cruises and combined these with topography data in the National Geophysical Data

Center's Coastal Relief Model in a Global Information System (GIS) database. Generalized

Additive Modeling procedures in the R statistical software package were used to investigate the

effect of bathymetry on sperm whale distributions. These showed maximum detection rates at

slopes of around 6 degrees and depths of 1000-600m. Our intention is to apply the same

approach to all data collected on S-tag and photo-identification cruises conducted during SWSS

and, in collaboration with other members of SWSS, to include other habitat parameters in the

analysis.

Abundance: Line transect techniques have been used to estimate the abundance of the many

species of cetaceans which inhabit the Gulf of Mexico (Davis et al. 2000; Würsig et al. 2000).

However, line transect techniques are not that well adapted for estimating sperm whale

abundance. The major problem is that g0 (the probability of encountering an animal if it is on the

track line) is usually assumed to be one. As sperm whales dive for an average of 40 to 50

minutes, g0 tends to be smaller than one. A second potential problem consists in estimating group

size. Foraging sperm whales are usually spread out over several nautical miles (nm) and, due to

the length of their dives, only a small proportion of the group will be at the surface at any one

time. In the past, clusters, consisting of two or more individual sperm whales less than 100 m
92

Figure 4.4.2. Survey track lines designed using the Distance Program (top) and realized track

lines (below) during SWSS WSHC 2003 cruise.

apart and coordinating their movements (Whitehead and Arnbom 1987), have been used instead

of groups. As sightings of clusters are not independent, abundance estimates may be biased.

Mark-recapture techniques have some advantages for estimating sperm whale abundance, as

individuals older than calves can be recognized by natural marks on the trailing edge of their
93

flukes (Arnbom 1987). With experienced photographic techniques, the majority of a population

of sperm whales can be individually identified. Furthermore, mark-recapture techniques can

estimate the number of individuals utilizing an area and not, as do line transects, the number of

animals present in the area at any one time. Therefore, mark-recapture techniques tend to be

appropriate for many long-term assessment and management purposes. However, a disadvantage

of mark-recapture techniques for estimating a population size is that they can require extensive

time at sea to collect sufficient data. They also require at least two sampling occasions, which

often means more than one field season.

During the three weeks of field work in 2003, whenever whales were detected during daylight

and the weather allowed, one or two rigid-hulled inflatable boats (RHIB) were launched to

obtain photo-identifications of as many sperm whales as possible within a group. Whales were

approached slowly from behind, to within about 50 to 60 meters. Photographs of the flukes were

taken at the beginning of deep dives with a digital camera (Canon EOS D1) and 300 mm lens.

Before analysis, all photographs were graded for quality following the standard method

described by (Arnbom 1987). This takes into consideration the angle, tilt, and focus of the fluke

in the photograph. Grading is independent of amount of marking on a fluke, and thus

independent of how well an individual could be recognized from a good photographic image.

Image quality grading is an important step as it allows one to determine whether or not a

particular image is an adequate sample to show particular types of marks. The data set used to

estimate sperm whale population abundance is shown in Figure 4.4.3. As most of the

identification photographs came from a short period of time, three weeks each in 2002 and 2003,

the full open model described by Whitehead (1990) could not be applied. Instead, a simple open

model was fit to the data (SOCPROG, Whitehead 1999). The results indicate that approximately

262 individuals utilized our study area (95% Confidence Interval = 157 to 509).

This result is consistent with previous estimates of population size for this area. The results for

2002, using a closed model due to the paucity of data, indicated that 298 individuals utilized the

study area (95% Confidence Interval = 137 to 890). Therefore, by increasing the sample size and

by switching to a more appropriate model, we considerably reduced the confidence intervals on

the population estimate without finding a radical change in the estimate itself. During the

GulfCet studies, an estimation of sperm whale abundance was also made for the northern Gulf of

Mexico using line transect techniques (Davis et al. 2000). However, as their study area was

larger than ours, comparisons are difficult.

The results from mark-recapture techniques, using lagged identification rates, showed that, on

average, 195 (SE=122) individuals are present at any one time in the study area. These results

indicate that, as has been shown for other populations of sperm whales that have been studied in

detail, the home range of sperm whales span several hundred nautical miles (800 on average,

Whitehead 2003), and they move extensively within their home range. These results also are

consistent with the results from the S-tag tracking data that show some extensive movements

within the Gulf of Mexico (e.g., see section 4.1).

However, the present results are still based on a small sample size and only two 3-week field

seasons. Therefore, to gain confidence in our estimate and to reduce the standard error, data over

longer time periods are needed.

Site Fidelity: Site fidelity in cetaceans is taken to refer to a tendency for individuals to spend a

disproportionate amount of time in a restricted part of their home range and to return to this area

in subsequent years. In this usage, the term does not preclude movements into and out of an area.
94

Figure 4.4.3. Number of sperm whales photo-identified each year; data set used for abundance

estimates.

Before 2003, approximately 100 sperm whales were identified in the Gulf of Mexico with high

quality photographs. In 2003, 75 individuals were identified. Thus, the number of identifications

from 2003 represents a large percentage of all sperm whales identified in the Gulf of Mexico.

Because we had a rather even coverage of the study area in 2003, we would expect that, in the

absence of site fidelity, resightings of individuals in 2003 were more or less randomly distributed

within the study area. As we see below, this was not the case.

Out of the 75 individuals identified during 2003, 21 had been identified during previous years, at

time spans of 1 to 9 years. However, re-identifications were not random within the study area. A

total of 71% of the resighted individuals were encountered between 90°W and 88°W, or the area

just south of the Mississippi River Delta (MRD); and 100% were resighted between 91°W and

87°W. No resightings took place west of 91° or east of 87°, despite the extensive effort in these

areas.

Figure 4.4.4 shows the mean resighting distance for identified individuals over a time span up to

9 years. In most cases, the resighting distances were less than 50 nm, which is approximately the

total distance covered by an individual each day according to a variety of other studies

(Whitehead 2003). The maximum resighting distance was 110 nm.

These results suggest a high site fidelity for some animals in the MRD area, and thus possibly a

preferred area. The enhanced primary productivity due to the Mississippi River discharge may

increase food availability for sperm whales in this area and explain this preference.

0

10

20

30

40

50

60

70

80

Gulfcet 1994 Gulfcet 1996 All SWSS 2002 All SWSS 2003

n=10 n=11

n=46

n=75
95

Figure 4.4.4. Mean resighting distances (in nm) for identified individuals over a time span up to

9 years. The number of individuals resighted for each time interval is shown above

each bar.

Small Scale Movements: In most areas of the world, sperm whale diet is dominated by meso- and

bathypelagic cephalopods (Kawakami 1980). However, as methods of effectively sampling these

deep-living squid have not yet been developed (Clarke 1985), it has been impossible to directly

relate sperm whale distribution or abundance to the distribution of their prey. Furthermore, as no

modern whaling was conducted in the Gulf of Mexico, there are few data on sperm whale diet

for this region. The little information that exists comes from stranded whales and, for the most

part, still awaits analyses (Nelio Barros, pers. comm.). Thus, we do not yet know what sperm

whales in the Gulf of Mexico are mainly feeding on or the distribution/abundance patterns of

these prey. Consequently, it is unknown whether some areas of the northern Gulf of Mexico have

higher food resources than others.

Patterns of small scale movements have been shown to provide a good indication of feeding

success, inferred from the percentage of fluke-ups for which defecations are observed

(Whitehead 1996; Jaquet and Whitehead 1999; Whitehead 2003). Movement patterns may thus

be used to assess the food availability in a region (Jaquet et al. 2003; Whitehead 2003). In areas

where food is scarce, sperm whale groups tend to travel in a straight line, whereas in areas where

food resources are plentiful, groups tend to zig-zag over a much smaller area (Jaquet and

Whitehead 1999; Jaquet et al. 2003; Whitehead 2003).

During the 2003 field season, eight groups of sperm whales were followed with the aid of a

directional hydrophone used from a RHIB and with the help of visual and acoustic teams on the

R/V Gyre. The position of the RHIB was recorded automatically by linking a GPS to a palmtop

computer. Three of the eight groups were encountered in the western part of the study area, three

in the MRD, and two in the eastern part of the Gulf. The small-scale movements for the two

0

10

20

30

40

50

60

70

9 Years 8 Years 7 Years 6 Years 3 Years 2 Years 1 Years

n=1

n=11 n=9

n=14

n=1

n=3

n=1
96

groups that were followed for the longest time in each area are shown in Figure 4.4.5. These

results tend to suggest that, in June 2003, food resources were higher in the MRD than in the

eastern Gulf. However, these results should be taken with caution as the sample size is still very

low and statistical analyses could not fairly be performed.

Figure 4.4.6 shows the root mean square displacement of these eight groups of whales that were

followed for 8 to 12 hours. This result suggests that in the Gulf of Mexico, sperm whales travel

at an average speed of 4 km/hour. This is consistent with other studies on average speeds of

female and immature groups (Gordon 1987; Whitehead 1989) and suggests that this may be an

optimal speed for sperm whales (Whitehead 2003). However, this graph also shows that the

displacement reaches a plateau at about 14 km, suggesting that the area over which groups zigzag is smaller than off the Galápagos or Chile (Whitehead 2003). This result suggests that sperm

whales in the Gulf of Mexico may be foraging on small but dense patches of squid. Again, more

data are needed and we expect to increase sample size by collecting similar data on fine scale

movements in later cruises.

Characteristics of the Sperm Whale Population of the Northern Gulf of Mexico:

1. Social organization

Sperm whales have highly developed societies (Caldwell et al. 1966) and their strong social

organization allows them to communally take care of calves and defend against predators.

Females and immature sperm whales form long-term (>decades) associations of on average 10-

Western part of the 

study area

South of the Mississippi 

River Delta

Eastern part of the 

Northern Gulf

10 June

18 June

12 June

15 June

5 June

8 June

8h10

10h 12h

10h 10h30

7h30

18 n.miles

1000m

200m

200m

1000m

1000m

1000m

1000m

Figure 4.4.5. Small-scale movements of groups of sperm whales in different areas of the northern

Gulf of Mexico. Positions were plotted every hour.
97

Figure 4.4.6. Root-mean square displacements for 8 groups that were followed for 8 to 12 hours.

12 individuals called units (Whitehead et al. 1991; Christal et al. 1998). These units usually

associate with another unit for about one week to form what is commonly called the group or the

nursery group (Whitehead et al. 1991; Christal et al. 1998).

Due to the significance of social organization in female sperm whales, it is important to

investigate whether the population of the northern Gulf of Mexico follows a similar pattern of

organization as that in other areas. To investigate sperm whale social organization in the northern

Gulf, we used identification photographs collected during the SWSS project (2002 and 2003

field seasons, 109 individuals), as well as during the GulfCet project (1994 and 1996, 14

individuals). Furthermore, these 123 individuals were compared to the ~50 photo-identifications

taken during the SWAMP project by NOAA Pascagoula in 2000 and 2001 (North Atlantic and

Mediterranean Sperm Whale Catalogue). Although the maximum time span of the study was 9

years, most of the identifications came from the last SWSS field season, reducing the power of

the data set for examining long term patterns of social organization. Furthermore, due to the

difficulties of tracking a known sperm whale group at night using the R/V Gyre, sperm whales

were never photographed on subsequent days, and thus the casual acquaintances (or group

structure) could not be investigated. To determine the pattern of sperm whale social organization,

we used the software SOCPROG (Whitehead 1999), especially developed for this purpose.

Our data showed that on four occasions, two individual sperm whales were sighted together and

were then resighted together up to 9 years later. Similarly, on three occasions, three individuals

were first sighted together and were resighted together again 4 years later. These results suggest

that some individuals may have constant companions, which is consistent with the results from
98

the SOCPROG program showing that our data best fit a model of constant companions and rapid

disassociation. However these "snap-shot" images of time are not enough to describe details of

social structure.

2. Group size

Estimating group size in the field is difficult, as foraging sperm whales are spread out over

several nautical miles and as they spend about 75% of their time underwater. Therefore, group

size is usually estimated using identification photographs and experience shows that, on average,

two days are required for most individuals in a group to be identified (Whitehead 1999; pers.

obs). In this study, group sizes will be slightly underestimated as groups were never followed on

more than one day.

Figure 4.4.7 shows the results for 9 groups that were followed for 7 to 12 hours. Although group

sizes were probably slightly underestimated, these results suggest that groups are smaller in the

Gulf of Mexico than they are around the Galapagos Islands or Chile (Whitehead 2003).

However, our results cannot discriminate whether these groups are formed of only one unit or of

two small units, and thus additional data on groups followed on consecutive days are needed to

answer this question of social affiliation.

Group size may influence the size of prey patch that can be efficiently exploited. The analysis of

fine scale movements presented above is indicative of smaller prey patches.

Figure 4.4.7. Estimated group sizes for groups that were followed >7 hours in June 2003.

Numbers above bars represent times followed, in hr:min.
99

3. Occurrence of markings

In order to manage sperm whale populations, it is critical to have a good understanding of how

their populations are structured within and between oceans (Whitehead 2003). During the 1970s

and early 1980s, considerable efforts were put into defining within-oceans stocks (Donovan

1991), but success was very limited. Recent findings using genetic markers, occurrence of

markings on flukes, and vocalizations have shown no consistent differences among whales of the

same ocean (Whitehead et al. 1998; Dufault et al. 1999), and only small differences in

mitochondrial DNA between different oceans (Lyrholm and Gyllensten 1998; Lyrholm et al.

1999). The near-absence of population structure on a geographical level explains the limited

success of stock assessments within oceans (Whitehead 2003). However, no sample came from

the northern Gulf of Mexico population, and investigation on whether this population is similar

to other populations is being carried out using genetics research by SWSS scientist Dan

Engelhaupt. Our data on acoustics and type and extent of markings also will feed into the

population comparisons.

The degree of fluke marking on a sperm whale may vary between areas depending on factors

such as predation levels (Gordon 1987) and thus may be an indicator of stock separation (Dufault

and Whitehead 1998). The presence or absence of two types of marks, hole and missing portion

(Figure 4.4.8) were used to assess the differences in marking between the three regions of the

northern Gulf of Mexico, the Sea of Cortez, and the South East Pacific.

The results, given in Table 4.4.1, show that there is a significantly higher proportion of

individuals with holes and/or missing tips in the Gulf of Mexico than in the Pacific Ocean (Gtest:p<0.001). However, as expected, there were no significant differences between the two areas

of the Pacific (G-test: p>0.5).

We plan to compare the markings of the northern Gulf of Mexico population to other areas in the

Atlantic Ocean and particularly with the Caribbean, and to compare between areas within the

Gulf of Mexico to investigate differences in markings from whales of other adjacent areas.

Figure 4.4.8. Example of 2 mark types (underlined) used to investigate differences in markings

between regions.

Holes

Missing

tip

Distinct nicks
100

Table 4.4.1

Percentage of Individuals Having Holes and/or Missing Portions in Their Flukes

Northern Gulf of

Mexico, n=105

Sea of Cortez (Pacific

Ocean), n=565 (Jaquet

unpublished data)

Galápagos/Ecuador (Pacific

Ocean), n=289 (Dufault &

Whitehead 1998)

Percent of

individuals with

holes

35 9 15

Percent of

individuals with

missing portions

43 25 21

4. Calving rates

Investigating whether a population of sperm whale is increasing, decreasing or stable is almost

impossible to achieve by successively estimating abundance. It has been shown that for most

populations of cetaceans that have been studied to date, the errors in estimating abundance are

such that researchers would require decades to detect a trend in population abundance

(Thompson et al. 2000). Usually, by the time a negative trend is detected, the population has

already been considerably reduced. However, determination of demographic measures such as

recruitment or calving rates allows investigation of how well a population is doing over smaller

time scales of several years.

In both 2002 and 2003, the number of first-year calves, adult males, and other whales (adult

females and immatures of both sexes) were counted in each group (after Kahn et al. 1993). Firstyear calves do not lift their flukes upon diving and thus cannot be identified individually; thus,

following other researchers, only the minimum number of calves for each group was recorded. A

group included two calves if two of them were observed simultaneously, or if after leaving one

calf, the RHIB traveled in a straight line at a speed of over 10 km/h and another calf was sighted

ahead of the vessel. To be consistent with other studies (Kahn et al. 1993) and allow comparisons

between them, the relative abundance of mature males and first-year calves was calculated as the

total number of different males identified, or minimum number of first-year calves divided by

the number of other whales identified (adult females and immatures of both sexes).

The results, given in Table 4.4.2, indicate that a smaller proportion of first year calves and large

mature males may have been encountered in the Gulf of Mexico in comparison to the Sea of

Cortez. However, this difference was not significant (G-test: p=0.26 and p=0.053 respectively).

A larger sample size is needed before conclusions can be drawn.

5. Length distribution

Investigating the length distribution of a population of sperm whales will provide crucial

information on population structure such as age, sex, and maturity. As well as allow calculation

of population parameters such as pregnancy rate and average age at maturity (Waters and

Whitehead 1990). However, measuring sperm whales at sea is difficult as they spend most of

their time underwater and as only part of their body can be seen while at the surface. In the past,
101

Table 4.4.2

Proportion of 1st Year Calves and Large Mature Males in the Northern Gulf of Mexico Versus

the Sea of Cortez

Northern Gulf of Mexico,

n=104

Sea of Cortez, n=152

(Jaquet et al. 2003)

Proportion of 1st year calves 6.7% 11.2%

Proportion of large breeding males 0.96% 5.3%

two photographic techniques were used to measure sperm whales (Gordon 1990; Dawson et al.

1995); however, neither of them was suitable to use from the Gyre's RHIBs. Therefore, in the

past two years, we have been experimenting with another technique allowing us to measure

identified individuals from the Gyre's RHIBs.

This technique consists of taking an identification photograph with a calibrated digital camera

and 300mm lens, and simultaneously measuring the distance to the fluke with a laser range

finder. The fluke width then can be related to body length using a polynomial regression

calculated from whaling and stranding data. The accuracy of this technique has been tested by

repeatedly measuring known sperm whales off Kaikoura, New Zealand, and by comparing length

distribution of Kaikoura whales and Sea of Cortez whales derived with this method to expected

length distributions. These tests have shown that the technique gives reliable results and that the

coefficient of variation due to the technique itself is low (CV=1.9%) (Jaquet and Gordon 2003).

Figure 4.4.9 shows the length distribution for groups of female and immature sperm whales

(large breeding males were removed) for the northern Gulf of Mexico and the Sea of Cortez,

respectively. In the Sea of Cortez, the modal group is between 10 and 10.2 meters, which is what

is expected from whaling data (Clarke et al. 1980; Rice 1989; Kahn et al. 1993). However, in the

Gulf of Mexico, the whales are smaller than would be expected and significantly smaller than the

ones in the Sea of Cortez (comparisons of mean lengths, t-test: p<0.001).

Differences in length distribution can be due to a variety of factors, such as differences in

whaling histories, how close the population is to carrying capacity, food resources, and feeding

conditions in an area. More data and further analyses are needed before we can suggest possible

reasons for the small size of whales in the northern Gulf of Mexico.

An acoustic method for measuring sperm whale body length involves measuring the time delay

between the multiple sound pulses typically found within a sperm whale click: the so called inter

pulse interval (IPI). Norris and Harvey (1972) first suggested that these pulses may form as

sound was reflected between sound mirrors at the front and back of the sperm whale head and

realized that this could form the basis of a method for measuring the length of live whales in the

field. This was confirmed by Gordon (1991) who showed that the IPIs of whales were related to

photographically derived body length in a way that was consistent with Norris and Harvey's

hypothesis. Because many IPIs can be measured from a recording of a single whale, very precise

measures of body length can be made. Pavan et al. (1998) were able to provide evidence for

growth in a sperm whale from IPI analysis of recordings of the same whale made in two years.
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Figure 4.4.9. Length distribution for groups of female and immature sperm whales in the

northern Gulf of Mexico and in the Sea of Cortez.

In applying this method during the current project we faced two challenges. The first was that

recordings had to be made from small RHIBs in the open ocean. To overcome this, small-boat

recording systems were assembled. These consisted of two HiTech HT01 hydrophones on 20m

of cable and a hard disk recording system based on the Creative Labs Nomad recorder, which

was housed in a waterproof case. The second problem was that it could be difficult to recognize

the vocalizations of a known individual when, as was usually the case, recordings were being

made in the middle of a large aggregation of foraging whales. However, we found that if

recordings were made close to the fluke up position and immediately after the whales fluked,

then the clicks of the whale that had fluked could usually be distinguished and followed for a

minute or so. Analysis was restricted to these "identified" clicks. Recordings were analyzed

using the IFAW Rainbow Click Program (Gillespie and Leaper 1996); this has a special module

for measuring IPI using cross correlation to make accurate measurements of the time interval

between pulses. In twelve cases, both photographic and acoustic length measurements were

available for the same individual whale. These are plotted in Figure 4.4.10. Overall, the two

length estimates were well correlated (Pearson’s Coefficient 0.75, p<0.005, n=12), providing

further support for the validity of the photographic length-measuring approach used here. The

agreement between these two measuring methods also gives us confidence that our body length

results for the sperm whale population of the northern Gulf of Mexico are not biased.

6. Vocal repertoire

Genetic analysis can reveal genotypic differences between groups of animals from which

differential patterns of breeding can be inferred, and in some cases, though rarely in sperm

whales, more or less discrete breeding populations can be identified. Generally, very low levels

of interbreeding need to exist for many generations for such patterns to emerge. Groups of

animals can also differ from each other in non-genetically mediated ways too. For example,
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Figure 4.4.10. Plot of photographic and acoustic body length measurements of Gulf of Mexico

sperm whales.

differences in experience and in the way that individuals interact can lead to differences in

learned behavior. Such differences can become established very quickly, over time scales at

which many human impacts occur, and they may well reflect factors that are significant to

management. For example, animals may become either habituated or sensitized to human

disturbance depending on their exposure to it. Such learned differences can be particularly

informative in species in which there is cultural transmission of information.

In addition to the regular clicks and creaks that are associated with foraging, sperm whales make

stereotyped patterns of clicks called "codas". These are typically heard when sperm whales come

together at the surface in large tight groups to socialize. Recent work by Rendell and Whitehead

(2003) suggests that codas are learned within "family" groups so that groups have characteristic

repertoires of codas and coda types. These authors also provide evidence that codas reveal a

hitherto undiscovered level of social organization in sperm whales. Each social unit belongs to a

particular clan that can be distinguished on the basis of its coda repertoire. Units belonging to

particular clans can be sympatric but social units associate preferentially with other units that

belong to the same clan. Although clans can most easily be discriminated on the basis of coda

vocalizations, there are indications that clan members share other behavioral, physical and

genetic similarities.

Recordings containing codas from the Gulf of Mexico, the Azores and the Caribbean were

analyzed using Rainbow Click, which has customized routines for coda analysis. The current

dataset, which has been assembled over several years and to which a number of analysts have

contributed, contains 3,194 Gulf of Mexico codas, 3,044 codas from the Azores and 1,927 codas

from the Caribbean. Some 38 different codas were identified in this dataset using k-means

cluster analysis. Further cluster analysis indicated the existence of three distinct acoustic clans.

All units encountered in the Gulf of Mexico were members of a single, very distinct clan and

Median Photogrammetric Length

8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5

Median Acoustic Length

13

12

11

10

9

8

7

Median Photogrammetric Length

13

12

11

10

 9

 8

 7

Mediam Acoustic Length
104

there were only three occasions on which units of this clan were encountered outside the Gulf,

and then always in the Azores. The other two clans were not as geographically distinct as the

"Gulf of Mexico" clan, although one tended to predominate in Caribbean encounters. These

results are preliminary and will be refined as new data are analyzed, but they fit the pattern

revealed by the photo-identification, genetic and satellite tag work also completed as part of

SWSS which indicates that the population of sperm whales in the northern Gulf of Mexico that

have been the subject of most of the SWSS and SWAMP studies are a discrete and relatively

small population.

Conclusions and Future Work

On this cruise, we adapted and applied what must now be considered the "traditional" sperm

whale research approach: using techniques of photo-identification, photogrammetry, observation,

acoustic tracking, recording and analysis. Many of these methods will yield the best information

when applied to long-term studies, but here they are already providing information on the basic

biology of this population which expands on and complements the data being collected by other

components of SWSS using exciting new techniques. It is encouraging to find that where the

research topics overlap, the picture being provided by these different approaches is in good

agreement. In particular, they are all pointing to the existence of a small population in the

northern Gulf that is remarkably discrete and isolated when compared to other sperm whale

populations, despite the fact that individuals can move great distances from the study area. Even

within the study area, there is evidence of distinct habitat preferences and a strong tendency for

certain individuals to show inter-annual fidelity to particular sites. There are also indications of

some biological differences between the sperm whales encountered here and those that have

been studied in other areas.

Acknowledgements

This research was conducted using software Logger 2000 and Rainbow Click developed by the

International Fund for Animal Welfare (IFAW) to promote benign and non-invasive research.

4.5 Tracking Sperm Whale (Physeter macrocephalus) Dive Profiles Using a Towed

Passive Acoustic Array

Dr. Aaron Thode1

1

Marine Physical Laboratory, Scripps Institution of Oceanography, San Diego, CA 92093-0205

The Minerals Management Service (MMS) funded a research project to determine whether dive

profiles of foraging sperm whales could be obtained using acoustic arrays towed behind a ship.

The ability to non-invasively collect such data would permit the collection of information about

dive descent rates, foraging depth, and possibly foraging time for a large number of animals over

a large geographic area, under various noise conditions. In the long term, the ability to extract

sperm whale range and depth information from towed arrays would be of great use in mitigation

efforts by MMS and the oil industry in the Gulf of Mexico, because the sound field from an

airgun array is highly directional, and knowledge of range and depth of a sperm whale is needed

to accurately determine what sound levels foraging animals are receiving in the vicinity of an

airgun array.

The work in 2002 and 2003 has shown that a passive acoustic method that uses two or three

hydrophones deployed as either a vertical or large-aperture towed array can be used for tracking

sperm whale dive profiles. The relative arrival times between the direct and surface-reflected

acoustic paths are used to obtain the ranges and depths of animals with respect to the array,

provided that the hydrophone depths are independently measured. Besides reducing the number

of hydrophones required, exploiting the surface reflections simplifies automation of the data

processing.
105

The 2002 deployment consisted of two short-aperture towed arrays separated by 170 m. In 2003,

the configuration shown in Figure 4.5.1 was tested off the R/V Ewing, by attaching a rope to the

end of a standard towed array, manufactured by SEAMAP, Inc. An autonomous acoustic flashmemory recorder (effectively an underwater Apple iPod) was attached to the rope so that the

total array system was about 200 m long, sufficient to track animals out to 1000 m range. Ship

noise was used to time-align the acoustic data. The recorder, manufactured by Greeneridge

Sciences Inc., measures depth, temperature, and orientation as well. Future deployments will

seek to get even wider separations to enable tracking to longer ranges.

Sperm whale ranges and depths can be measured because the sounds made from the whales

ricochet off the ocean surface and bottom. By measuring when these "echos" arrive relative to

the original sound, the position of the whale can be determined. Examples of echos are shown on

a spectrogram in Figure 4.5.2. The theory of tracking is simple; the challenge is finding a way to

extract this information automatically from the sound recordings. Note from the figure that three

pieces of information can be obtained from each sound or 'click' an individual makes: the

difference between the arrival times of the direct and surface-reflected paths on the forward and

rear hydrophones, and the arrival time difference between the direct paths on both hydrophones.

In 2003, major progress was made in extracting the tracking information from the sound data.

Figure 4.5.3 shows how one computer algorithm was able to extract the relative arrival times of

the surface echoes relative to the direct paths (top two subplots) and the relative arrival times of

the sounds on two different hydrophones (bottom subplot). Cepstral analysis was used to

estimate times for the forward (top panel) and rear (middle panel) hydrophones, while a "rhythm

analysis" that compared sets of 9 inter-click interval sequences between phones was used to

derive the times in the lower panel. Note the presence of an additional "ghost" curve in the lower

Figure 4.5.1. Deployment geometry of towed passive acoustic range-depth tracking system. This

illustrates the acoustic propagation paths used in the 2003 tracking configuration.

An autonomous acoustic recorder is attached to a 5/8" polypropylene rope, whose

end is attached to a towed acoustic array manufactured by SEAMAP, Inc.
106

Figure 4.5.2. A spectrogram display illustrating the measurements required for range-depth

tracking. It is taken from data collected during one nighttime test, 5 September

2002, using the Ishmael display software of David Mellinger. The top spectrogram

display shows data from the forward, WHOI hydrophone, and the bottom display

shows a simultaneous recording from the rear, Ecologic hydrophone.

panel. This represents the arrival time difference between the surface reflection on the rear phone

and the direct path on the forward phone.

If the hydrophone depths and relative arrival times of the echos are found, the range and depth of

the animal can be tracked. Figure 4.5.4 presents one result from 2003 that shows how the ship

inadvertently passed almost directly over a whale foraging at 500 m depth. Standard tracking

methods would have placed this animal 500 m to the side of the tracking vessel. This result thus

demonstrates how a real-time range-depth tracking system might aid mitigation efforts during

seismic surveys. A peer-reviewed publication on these methods has been submitted, and a more

robust array deployment for 3-D tracking during 2004 is being planned.
107

Figure 4.5.3. Example of automated estimates of relative arrival times of the surface echoes

relative to the direct paths (top two subplots) and the relative arrival times of the

sounds on two different hydrophones (bottom subplot) using data from 19 June

2003.
108

Figure 4.5.4. Example of range-depth tracking even in the presence of hydrophone clipping. The

inverse stability factor versus time is given in the top panel. The range (m) of the

whale from the vessel's forward hydrophone through time is shown in the middle

panel. The depth (m) of the whale through time is shown in the lower panel. The

ISP is a rough measure of a whale’s azimuth. Values greater than one indicate the

whale is forward of the array. The black squares mark independent localization

estimates opportunistically obtained by exploiting bottom-reflected acoustic paths.

Black bars on squares represent one standard deviation of the estimates derived

from bottom returns over a 20 sec interval.
109

4.6 Habitat Characterization: Eddy Forced Variations in On-margin and Off-margin

Summertime Circulation Along the 1000-m Isobath of the Northern Gulf of Mexico,

2002-2003

Douglas C. Biggs1, Matthew K. Howard1, Ann E. Jochens1, Steven F. DiMarco1, Robert R. Leben2

, and Chuanmin Hu3

1

Department of Oceanography, Texas A&M University, College Station TX 77843 2

Colorado Center for Astrodynamics Research, University of Colorado, Boulder CO 80309 3

College of Marine Science, University of South Florida, St Petersburg FL 33701

Areas along the 1000-m isobath where sperm whales were encountered in summer 2003 are not

the same as those where sperm whales were found in summer 2002. Post-cruise reports from R/V

Gyre cruises in summers 2002 and 2003 and from R/V Ewing for summer 2003 summarize

where sperm whales were (and show where they were not) found after searching along the 1000-

m isobath with combined BigEye and hydrophone surveys. However, since each post-cruise

report is focused on a specific 3-4 week time period, these cruise reports alone do not convey the

magnitude of circulation differences along the 1000-m isobath between summer 2003 and

summer 2002. Our purpose in this short summary is to provide a synopsis of how eddy-forced

variations in on-margin and off-margin flow apparently drove these between-summer

differences.

In preparing this summary, we merged hydrographic data collected from the oceanographic ships

with remote sensing of sea surface height (SSH) mapped by satellite altimeters and with ocean

color mapped by the SeaWiFS satellite. The list of co-authors who contributed to this summary

is a lengthy one, since our synopsis is based on cooperative work among three institutions. Texas

A&M University oceanographers are responsible for collection and analysis of hydrographic

data from the oceanographic ships and for the overall program management that is in place

among the universities cooperating for the Sperm Whale Seismic Study (SWSS). Our co-authors

from the Colorado Center for Astrodynamic Research (CCAR) at the University of Colorado

(CU) and from the Institute for Marine Remote Sensing (IMaRS) at the University of South

Florida (USF) provided altimetry and ocean color data, respectively. By the time of the SWSS

workshop in Houston, TX, in November 2003, CCAR had reprocessed the 2002 and enough of

the 2003 near-real-time altimetry data to allow us to animate a 21-month hindcast of the basinwide SSH field. This covered the period from 1 January 2002 through 30 September 2003 with a

one-day time step. We showed this analysis product at the November 2003 workshop. IMaRS

collects and processes SeaWiFS data with a focus on the eastern Gulf of Mexico (east of 91°W).

They generate analysis products, including composites every week and composites every month.

By the time of the November 2003 workshop, this IMaRS hindcast included the 22 month period

January 2002 through October 2003.

Loop Current Dynamics and Slope Eddies in 2002

The SSH analysis product shows that a gradient of increasing SSH from north to south (i.e., from

shelf to slope) existed 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 hindcast 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 800-1000 m isobaths, doming of

nutrient-rich midwater close to the surface likely favors enhanced planktonic new production

along this continental margin (Wiseman and Sturges 1999; Biggs and Ressler 2001). Such

conditions, we believe, jump start biological production throughout the food chain, and likely

result in more potential prey for sperm whales and other apex predators.

Early in 2002, the Loop Current (LC) shed a Loop Current Eddy (LCE), named "Quick Eddy".

In March-April 2002, Quick Eddy cleaved into two pieces: a western QE1 and a central QE2. In
110

the first half of May 2002, QE2 shed a warm filament that extended north into the DeSoto

Canyon (Figure 4.6.1). During the second half of May and the first half of June 2002, this warm

filament consolidated into a warm slope eddy (WSE), the inshore edge of which reached the

Mississippi Canyon region south of the Mississippi River delta (see the middle and end-of-month

summary figures in the left column of Figures 4.6.2 and 4.6.3). A composite of SeaWiFS ocean

color imagery for the month of June 2002 shows that the anticyclonic circulation around this

WSE pulled green water offshore into the eastern part of the SWSS field area (Figure 4.6.4, top

panel). A property-property plot of ship-measured chlorophyll fluorescence (a proxy for

chlorophyll standing stock) versus surface salinity is a generally straight-line relationship (Figure

4.6.5). Such a straight-line relationship denotes the entrainment process is largely conservative.

Thus, the high chlorophyll concentration off-margin arises from seaward transport of

phytoplankton coming in from river or estuarine sources. Chlorophyll concentrations change

(decrease) off-margin primarily due to mixing with adjacent, low-chlorophyll surface water,

although some of the scatterplot data (the green-color points that lie above the straight line in

Figure 4.6.5) suggest there was some local phytoplankton growth from "new" nutrients as well.

Figure 4.6.1. SSH field for 10 May 2002. This field illustrates the warm filament extending on

margin from the northern periphery of Loop Current Eddy QE2.
111

Figure 4.6.2. Comparison of SSH conditions along the northern margin of the Gulf of Mexico in

May 2002 and May 2003.

In mid-June 2002, the gradient of increasing SSH over the slope between 94°W and 88°W

indicated there was west to east flow along most of the 1000-m isobath, but off-margin flow west

of 94°W and east of 88°W (Figure 4.6.3, top left panel). Hydrographic data (XBT, CTD, and

ADCP data) from the SWSS 2002 S-tag cruise confirm that off-margin flow was present in both

of these areas. This off-margin flow of "green water" was best developed east of 88°W. It was

strongest during June and July 2002 while the anticyclonic WSE remained in DeSoto Canyon

(Figure 4.6.6, top panels). In October 2002, by which time the WSE was no longer visible as a

local SSH high in the DeSoto Canyon, the off-margin transport of "green water" was much

reduced (Figure 4.6.6, bottom panels).

Animation of the SSH altimetry maps makes it easy to see that between early July and mid

August 2002 what during the 2002 S-tag cruise was a large-scale anticyclonic circulation in the

deepwater south of 27°N had broken up into several much smaller anticyclonic eddies. By midAugust, when the SWSS 2002 D-tag cruise sailed for sea, 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 in July and

August 2002 (Figure 4.6.7). Hydrographic data from the SWSS 2002 D-tag cruise confirm that
112

off-margin flow of low salinity green water was present in most of the region from 90°W to

88°W. A property-property plot of chlorophyll fluorescence versus salinity indicates there was

"new" production as well (Figure 4.6.8). The 2002 D-tag cruise also documented locally high

chlorophyll in a "bulls-eye" of high ocean color visible in the August 2002 monthly composite of

SeaWiFS imagery in deepwater southeast of Mississippi Canyon (Figure 4.6.7, lower right). The

SSH data show this high-color feature was a mesoscale cyclonic circulation (Figure 4.6.7, lower

left). Several groups of sperm whales were encountered in and around this feature during the

2002 D-tag cruise and to the northeast in the DeSoto Canyon.

Figure 4.6.3. Comparison of SSH conditions along the northern margin of the Gulf of Mexico in

June 2002 and June 2003.
113

Figure 4.6.4. Comparison of monthly composite SeaWiFS imagery and SSH conditions for June

2002 and June 2003.
114

Figure 4.6.5. Chlorophyll fluorescence versus salinity for June 2002 S-tag cruise on Gyre. This

plot illustrates the generally conservative (straight-line) mixing of low salinity

"green water" with high salinity "blue water". Green-colored data denote

measurements in the high-shear edge of the green water entrainment region.
115

Figure 4.6.6. Comparison of monthly composite SeaWiFS imagery and SSH conditions for June

2002 and October 2002.
116

Figure 4.6.7. Comparison of monthly composite SeaWiFS imagery and SSH conditions for July

2002 and August 2002.
117

Figure 4.6.8. Chlorophyll fluorescence versus salinity for September 2002 D-tag cruise on Gyre.

This plot illustrates that non-conservative (non-straight-line) relationships now

prevail. "New" production is indicated when fluorescence values do not follow

straight lines.

Loop Current Dynamics and Slope Eddies in 2003

Animation of the SSH altimetry maps shows that during the first four months of 2003, as in

January-April 2002, circulation was generally cyclonic along the 1000-m isobath in the NE Gulf,

including Mississippi Canyon and DeSoto Canyon. The LC surged north of 27°N during this

four-month period. In late February 2003 it appeared as if an LCE would separate. However, this

anticyclonic circulation feature re-attached to (was recaptured by) the LC. The next LCE

separated from the LC during the first two weeks of May 2003. This separation produced a large

and energetic LCE, which Horizon Marine named "Eddy Sargassum" (Figure 4.6.9). SeaWiFS

imagery confirms the mid-May 2003 separation. A 7-day composite for 18-24 May (Figure

4.6.10) shows high-chlorophyll "green water" being drawn off margin near 86°W and entrained

south to about 26°N and then west of about 90°W in the high-velocity periphery of this new,

super-size LCE.
118

Figure 4.6.9. SSH conditions in May 2003, showing separation of LC Eddy "Sargassum."
119

Figure 4.6.10. SeaWiFS composite for 18-24 May 2003, confirming separation of LC Eddy

"Sargassum."

The SSH animation shows that after separation from the LC, Eddy Sargassum pushed northward

(on-margin) and that the long axis, which initially was oriented N-S, rotated clockwise (Figure

4.6.2, right-hand panels). By the middle of June 2003, the long axis was oriented W-E and its

northern periphery extended almost to the shelf-slope break (Figure 4.6.3, right-hand panels).

CTD 5, taken from Gyre on 11 June 2003, confirms the presence of Subtropical Underwater

(salinity > 36.7) in the upper 200 m (Figure 4.6.11). This CTD and the XBTs dropped 9-11 June

and again 17-20 June show that the 15°C depth along the northern margin was deeper than 250

m (Figures 4.6.12 through 4.6.14). XBTs dropped from Ewing while this vessel searched for

sperm whales in Mississippi Canyon during 11-17 June 2003 also show 15°C depths greater than

250 m (Figure 4.6.13). These hydrographic data collected from both oceanographic vessels

confirm that, in mid-June 2003, Mississippi Canyon was full of Caribbean water that had

advected north with the LC (Figure 4.6.15).

Sperm whales were not encountered by either ship in the area of 89.3-90.5°W where and when

LCE Sargassum was interacting with the 1000-m isobath (Figures 3.1.2 and 3.1.6; Tables 3.2.7

and 3.2.8). Rather, groups of whales were found west of 90.5°W and east of 89.3°W, where 15°C

depths and the SSH maps indicate these areas were outside the core of Eddy Sargassum (Figures

4.6.14, 4.6.15, and 4.6.16). Data from Gyre confirmed there was a very sharp surface front at the

northern periphery of Eddy Sargassum. On the morning of 16 June 2003, Gyre documented the

presence of a sharp boundary between low-chlorophyll "blue water" and higher-chlorophyll
120

Figure 4.6.11. CTD profile from 11 June 2003 shows subsurface evidence for Subtropical

Underwater.

"green water" near 28.87°'N, 88.33°W (Figure 4.6.17). From 16 to 18 June 2003, Gyre followed

several groups of sperm whales in the green water northeast of this front. In contrast, none were

found inside the blue water front marking the northern periphery of the LCE. This was not

unexpected, since the GulfCet 2 program also found sperm whales to be uncommon in the

interior of LCEs (Biggs et al. 2000).

In June 2003, along the boundary between blue and green water just northeast of Mississippi

Canyon, we documented a "hot spot" of locally high chlorophyll fluorescence. A propertyproperty plot of chlorophyll fluorescence versus salinity (Figure 4.6.18) suggests this resulted

from turbulent mixing that brought "new" nutrients to the surface. When Gyre returned to this

area during the SWSS 2003 S-tag cruise, however, the hot spot had relaxed and mixing of green

water with blue water was generally conservative (Figure 4.6.19). During the two weeks that

passed between the time this area was visited by the SWSS 2003 WSHC cruise and the 2003 Stag cruise, the SSH time series shows that Eddy Sargassum had moved away from (rebounded

seaward from) the 1000-m isobath. In confirmation of this change in geometry, CTDs taken and

XBTs dropped during the 2003 S-tag cruise show no evidence for Subtropical Underwater, and

15°C depths were < 255 m (Figure 4.6.20). Thus, hydrographic conditions along the 1000-m

isobath appear to have returned to "normal" by mid-July 2003, and on the 2003 S-tag cruise

sperm whales were again encountered between 89-91°W, as well as to the northeast of

Mississippi Canyon (Figures 3.3.7 and 3.3.10).

TS Plot for CTD 5

0

5

10

15

20

25

30

34.6 34.8 35 35.2 35.4 35.6 35.8 36 36.2 36.4 36.6 36.8 37

CTD 5 at 88.9W (11 June 03); 15C depth = 242 m

Subtropical Underwater

(Caribbean origin) has

subsurface salinity > 36.5

Salinity

Temperature
121

The comparison of SeaWiFS monthly composites for June 2002 and June 2003 (Figure 4.6.4)

shows more green water was entrained and moved farther offshore in summer 2002 than summer

2003. A similar comparison of April 2003 (before LCE separation) with June 2003 (LCE close

off-margin) is convincing evidence that this entrainment was forced by the presence of LCE

Sargassum close off-margin (Figure 4.6.21). Recall that a comparison of SeaWiFS monthly

composites for June 2002, with a WSE present on the 1000-m isobath, and October 2002, with

no WSE present, showed that WSEs also can entrain shelf water and move it off margin (Figure

4.6.6), although the magnitude of the entrainment and transport off-margin was not as great as

during summer 2003 when a full-blown LCE is present.

Figure 4.6.12. Relation of SSH to 15°C depths from XBT drops in early June 2003. XBT

stations from Gyre are diamonds and from Ewing are squares. Reported are the

15°C depths for three areas. The white line denotes the XBTs from Gyre for

which the range of depths are given.
122

Figure 4.6.13. Relation of SSH to 15°C depths from XBT drops in mid-June 2003. XBT

stations from Gyre are diamonds and from Ewing are squares. Reported are the

15°C depths for two areas. The white line denotes the XBTs from Gyre for which

the range of depths are given.
123

Figure 4.6.14. Synopsis of 15°C depths, determined during SWSS 2003 WSHC cruise on Gyre,

plotted versus longitude. Compare this with Figures 4.6.12 and 4.6.13 and with

the following Figure 4.6.15 to see locations in relation to SSH. Inset shows that

the 15°C depth is a proxy for SSH.
124

Figure 4.6.15. Summary plot of location of XBT stations occupied by R/V Gyre and R/V Ewing

in June and July 2003, superimposed on SSH conditions for mid-June 2003.
125

Figure 4.6.16. Sperm whale sightings superimposed on 15°C depth during SWSS 2003 WSHC

cruise on Gyre.
126

Figure 4.6.17. At the northern edge of LCE "Sargassum," the SWSS 2003 WSHC cruise

encountered a sharp surface front on 16 June 2003.
127

Figure 4.6.18. Chlorophyll fluorescence versus salinity on SWSS 2003 WSHC cruise on Gyre.

Plot shows the "hot spot" of locally high chlorophyll fluorescence at the

boundary between blue water and green water during the cruise.
128

Figure 4.6.19. Chlorophyll fluorescence versus salinity on SWSS 2003 S-tag cruise on Gyre. In

contrast to the 2003 WSHC cruise, mixing was generally conservative (simple

dilution of green water with blue water) during the 2003 S-tag cruise.
129

Figure 4.6.20. Relation of SSH to 15°C depths from XBT drops made on the July 2003 S-tag

cruise on Gyre. XBT stations are diamonds.

Summary

Loop Current Eddies and slope 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 800-1200 m isobaths determine whether low salinity green

water flows off margin, or if high salinity blue water flows on margin. Green water is

biologically rich and we hypothesize it supports more prey for the squid upon which whales

prey. Locally high chlorophyll can develop at the periphery of eddies, when or where high

velocity currents (> 2 knots) create vertical shear and thus upwelling of nutrients from midwater.

Moreover, 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 continental slope

of the Gulf of Mexico. LCEs, in contrast, appear to generate the opposite effect.

There is hydrographic evidence (e.g., deep 15°C depths) that, when the large, energetic LCE

Sargassum interacted with the 1000-m isobath in early June 2003, it displaced the upper 1000 m

or so of usual water in the Mississippi Canyon area with low-nutrient, low-chlorophyll "ocean
130

Figure 4.6.21. Comparison of monthly composite SeaWiFS imagery and SSH conditions for

June 2003 and April 2003.

desert" water of Caribbean origin. We hypothesize that sperm whales usually seen in this area

(i.e., summer 2002) moved west and/or east out of this area during early June through late June

when this LCE reached farthest north along the margin. Whales were in greater abundance in

summer 2003 west of 92°W and east 88.5°W than in the region 89.3-90.5°W where the LCE

reached its shallowest point along margin. We presume the whales left when their deep-living

squid prey was also displaced by this bolus of northward-moving Caribbean water. Return to

normal conditions of hydrography (and squid prey?) appears to have occurred after this LCE

moved back (rebounded) into deeper water, since by early July 2003 the 15°C depth had returned

to normal levels, and whales were again encountered in Mississippi Canyon.

Acknowledgments

TAMU and CCAR support came from MMS-TAMRF cooperative agreement 1435-01-02-CA85186. USF support came 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.
131

4.7 Habitat Characterization: Upper-Ocean Current Observations During Summer:

2002 and 2003 Central Slopes of the Northern Gulf of Mexico

Dr. Steven F. DiMarco1, Ann E. Jochens1, and Matthew K. Howard1

1

Department of Oceanography, Texas A&M University, College Station, TX 77843-3146

Ship-mounted acoustic Doppler current profiler (ADCP) observations were recorded during each

leg of SWSS cruises during the summers of 2002 and 2003. Shipboard ADCPs provide profiles

of current speed along the ship track. Up to two ADCPs of different operating frequencies were

used: a 150-kHz narrowband model and a 38-kHz phased-array Ocean Surveyor Model. Only

150-kHz ADCP data were collected in 2002; both instruments were available in 2003. The

nominal vertical range of the 150-kHz ADCP is about 200 m; the 38-kHz is about 800 m. The

ADCP data were collected in five-minute intervals, which translate to 2-3 km horizontal spatial

resolution when the ship is traveling at 8 knots (4 m/s). Vertical resolution was set to 4 m bins

for the 150-kHz and 16-m bins for the 38-kHz ADCP. Position and pitch, roll, and yaw

(navigation) data were recorded at 1-second intervals using an Ashtech 3DF GPS antennae array.

Differential GPS fixes were used as available. The navigation data were merged with the raw

ADCP data during post-cruise processing. Jochens and Biggs (2003) give a description of the

standard ADCP processing protocol and quality control procedures used (see also Jochens and

Nowlin 1999).

It is critical when processing shipboard ADCP data to obtain accurate estimates for ship velocity.

This is because the downward looking transducers of the ADCP are providing estimates of fluid

movement past the transducer head. The fluid movement is the vector sum of the ship velocity

and the ocean current velocity. The ship speed therefore must be subtracted from the transducer

speed to yield the current velocity. Complicating this calculation is the fact that the ship speed is

typically much larger than the current velocity (order 20-30:1) so ship speed must be estimated

with high precision. Further, an elaborate scheme to correct the ADCP output for an offset with

respect to the ship’s beam must also be used (Murphy et al. 1992) using a regression of the GPS

determined ship velocity and the ADCP-determined ship bottom track velocity.

Several quality control indicators, which aid in the interpretation and analysis of horizontal

velocity estimates, are built into the ADCP estimates. These include vertical and error velocities,

which provide an indication of homogeneity of the fluid flow; percent good, which reports the

percentage of usable or "good" pings used to create the five-minute average ensemble;

correlation, which quantifies the correlation of the outgoing acoustic pulse with the received

scattered pulse; and echo intensity, which is a measure of received signal strength.

Nowlin et al. (2001) summarized the basic features of currents in the deepwater Gulf of Mexico.

These are briefly described. The energetic motions associated with the Loop Current, Loop

Current Eddies, and other smaller and weaker anticyclonic and cyclonic features usually

dominate the surface circulation of the deep Gulf of Mexico. Except for the occasional hurricane,

wind driving is usually weaker than the mesoscale eddy forcing. Tidal forcing is dominated by

the M2, K1 and O1 tidal constituents and is also weak (2-3 cm/s in the deep Gulf). Freshwater

forcing is also weak except in the coastal currents of the continental shelf.

Sea surface height (SSH) estimates from altimeter data (courtesy of R. Leben, CCAR) reveal that

the summers of 2002 and 2003 were typical in terms of the physical features of the circulation of

the northern Gulf of Mexico.

During the summer of 2002, the Loop Current was south of the northern slopes of the Gulf of

Mexico and not directly influence the circulation there. Several small-scale (50 km) circulation

features were present on the northern Gulf slopes. The cruise track roughly followed the 1000-m
132

isobath. Currents along the 1000-m isobath generally followed contours of SSH height indicating

mostly geostrophic flow. However, there were departures from this. This can be expected as SSH

imagery is based on a 10-day blend of altimeter data. Therefore, the movement of circulation

features during this period and features smaller than about 30 km are generally not reflected well

in the altimeter data but can often be seen in the ADCP data.

The mean vertical profile of current speed during the summer 2002 S-tag cruise shows speed

decreasing with depth from about 30 cm/s at the surface to about 10 cm/s at 200 m. The standard

deviation of current shows a similar pattern with slightly less amplitudes of 25 cm/s to 10 cm/s.

The maximum speed profile during the cruise also decreased with depth from 70 cm/s at the

surface to 40 cm/s at 200 m. Current speeds seen during the September 2002, D-tag cruise were

less than during the June cruise. Mean speeds ranged from 20 cm/s at the surface to 10 cm/s at

200 m; maximum speeds ranged from 60 cm/s to 30 cm/s.

A newly detached Loop Current Eddy, Eddy Sargassum, dominated the circulation of the

northern Gulf of Mexico during the summer of 2003. The center of this eddy was roughly

located at 27°N, 87°W on 11 June 2003 (Figure 4.6.1). Currents were generally quiescent in the

western regions of the cruise track, i.e., west of 91°W. However, east of 91°W the currents were

intense on the outer northern limb of the Eddy. Mean currents exceeded 40 cm/s near surface and

decreased to less than 5 cm/s at 800 m. Current standard deviation. Maximum currents exceeded

120 cm/s near surface and near the Eddy and decreased to 50 cm/s at about 300 m and 30 cm/s at

800 m.

Figure 4.7.1. Sea surface height anomaly field for 11 June 2003 with currents at 41 m from the

38-kHz ADCP superimposed. Loop Current Eddy Sargassum (red) generated large

surface currents (> 50 cm s

-1) and dominated the circulation of the northern Gulf of

Mexico during the summer of 2003.
133

4.8 Habitat Characterization: Midwater Trawling Program

Dr. John Wormuth

Department of Oceanography, Texas A&M University, College Station, TX 77843-3146

The objectives of the midwater trawling were to sample the potential prey fields at depths where

sperm whales are known to feed and to sample areas where whales are actively feeding as well

as areas where they are not observed to be feeding. In order to achieve these objectives, we used

a 14.8 m2 Isaacs-Kidd midwater trawl with an inner liner mesh of 4 mm terminating in a 0.333

mm mesh plankton net. The fishing intervals chosen were 0-400 m, 400-600 m and 600-800 m.

The two deeper intervals were selected to partition the feeding depths of whales recorded in the

previous field year. The 0-400 m interval was chosen to look at those components the trawl

would sample on its way down to the deeper intervals. Depth and temperature were recorded

with a Sea Bird TDR Model 39. Volume filtered was measured with a General Oceanics flow

meter.

Tows were taken at night following the day's completion of over-the-side operations. This

limited our ability to sample in "non-whale" areas, but reduced time lost to reacquiring whales

prior to dawn. A total of 24 successful trawls were completed in cyclonic, anticyclonic, and other

regions. Samples were sorted into fish, crustaceans and cephalopods. Displacement volumes

were measured for each component. Temperature profiles for each of the three categories were

plotted and showed remarkable uniformity with each category.

The first hypothesis tested, using an ANOVA was: there is no difference in component

displacement volumes for tows to different maximum depths. The only statistically significant

results showed that fish biomass in the 0-400 m tows was greater than for tows from 400-600 m

and for tows from 600-800 m.

The second hypothesis tested, using a significance test of correlation coefficients was: there is no

difference in displacement volumes in different environments. Table 4.8.1 shows the results of

these comparisons. Fish and crustaceans displacement volumes showed the highest significant

positive correlation coefficient.

A predictable relationship was established between meters of wire out and depth of the trawl

(Fig. 4.8.1). This allowed us to reliably fish in the targeted depth intervals and minimize the

volume filtered in the non-targeted intervals by paying out wire quickly going through layers not

of interest and slowing wire speed in layers of interest. We were able to average 50% of the total

volume filtered in the targeted layer (Fig. 4.8.2).

The largest squid collected was a Histioteuthis arcturi of 30 cm total length (7.8 cm mantle

length) that was caught in Trawl #5 in the westernmost series of trawls fished mostly in the 600-

800 m interval. This family of squid is often found in the stomachs of sperm whales and can

grow to mantle lengths of 20 cm or more. The most common family in the trawl collections was

Enoploteuthidae. These species do not grow large enough to be in the diet of sperm whales. No

identifiable giant squid (Architeuthidae) juveniles were collected. The squid eggs dip netted are

presently being examined at the Smithsonian for comparison to other collections.

Dominant fish groups collected are: Gonostomidae, Stomiatidae (the bristlemouth Cyclothone);

Sternoptychidae (hatchet fishes), and Myctophidae (lantern fishes). At present, the cephalopods

and hatched fishes have all been identified to the lowest possible taxonomic level. Unidentified

specimens are juveniles. The myctophids are presently being worked up as are the crustaceans.

Dominant crustaceans to date are: Penaeidae (Sergestes and Gennadas), Euphausiidae

(Euphausia, Nematobrachion and Thysanopoda), and Caridea (Systellaspsis and Acanthephyra).
134

Table 4.8.1

Results of Z Tests of All Combinations of Displacement Volumes (DV) for All Trawls

Correlation

coefficient

Degree of

freedom

Z-Value Probability

level (p)

FISH DV, CRUSTACEA DV 0.69 23 3.81 0.0001***

FISH DV, SQUID DV 0.21 23 0.95 0.341

FISH DV, > 2MM DV 0.48 23 2.27 0.023*

FISH DV, < 2MM DV 0.44 23 2.08 0.038*

CRUSTACEA DV, SQUID DV 0.14 23 0.61 0.542

CRUSTACEA DV, > 2MM DV 0.29 23 1.25 0.211

CRUSTACEA DV, < 2MM DV 0.12 23 0.52 0.602

SQUID DV, > 2MM DV 0.45 23 2.08 0.038*

SQUID DV, < 2MM DV 0.09 23 -0.38 0.702

> 2MM DV, < 2MM DV 0.57 23 2.84 0.005**

* p < 0.05

** p < 0.01

*** p < 0.001

Figure 4.8.1. The relationship between meters of wire out and depth of the trawl for five tows

representing different wind and current conditions.
135

Figure 4.8.2. The volume filtered in the targeted depth interval as a percentage of the total

volume filtered for each trawl.

4.9 Habitat Characterization: 38-kHz ADCP Investigation of Deep Scattering Layers

Amanda M. Olson1, D. C. Biggs1, and S. F. DiMarco1

1

Department of Oceanography, Texas A&M University, College Station, TX 77843-3146

A hull-mounted 38-kHz phased-array ADCP was used to acoustically survey the continental

margin of the northern Gulf of Mexico during four SWSS cruises and two cruises of the MMSsupported Deep Gulf of Mexico Benthic study (DGoMB) in 2002-2003. ADCPs have been used

since the 1980's to measure the acoustic volume backscatter return from plankton in the water

column as a proxy for the standing stock of zooplankton and small-size micronekton, but in

practice these previous studies have generally been limited to the upper 200 meters due to the

relatively high frequency of operation (150-300 kHz). Although raw data from the 38-kHz

ADCP have not been corrected for signal losses from spherical spreading, the backscatter data

from this phased-array ADCP provides relative backscatter counts that are nonetheless useful

metrics to compare biological scattering layers. The daytime depth of the main deep scattering

layer (DSL) at 400 to 500 meters was resolved, and locally high backscatter intensity can be seen

down to 800 meters. Vertical migration rates between 2-12 cm/sec were calculated. Our main

objective was to image scattering layers of prey species below the main deep scattering layer

from 600 to 800 meters below the surface where, from the D-tag data shared by our colleagues

from Woods Hole Oceanographic Institution, we knew that Gulf of Mexico sperm whales were

diving during nighttime as well as daytime.

When relative backscatter from the mid-slope region of the northern Gulf of Mexico was

compared to the backscatter from the deep basin, we noticed more frequent and more intense

patches and layers of deep scattering below the main DSL from 500 to 800 meters over the mid-
136

slope (Figure 4.9.1). Patches and scattering layers below the main DSL were very infrequent in

the deep basin (Table 4.9.1). Although some vertically migrating animals descend down to 800

meters during the daytime, these patches appear to be independent of the vertical migrating layer

since they are present both daytime and nighttime and give a much higher intensity signal. From

the acoustic return alone, we are not able to tell what species are represented by these patches,

however we know that at 38-kHz the ADCP receives signal from scatterers from about 1 cm up

to 10 cm. So based on their size, these organisms are likely small fish and squid and their prey.

Because deep scattering was common over the slope and almost never observed in the deep

basin, these patches may represent important sperm whale prey species and could be correlated

with the location of sperm whales.

Table 4.9.1

Occurrence of Scattering Below the Main DSL (> 650 m) Out of the Number of Possible

Days in Water Less Than or Greater Than 1000 Meters for Each Cruise While Over the

Slope and Deep Basin

Cruise Name Occurrences in

< 1000 Meters

(800-1000)

Occurrences in

> 1000 Meters

SWSS 2002 S-tag 5/9 0/1

DGoMB August 2002 0/0 1/5

SWSS 2003 WSHC 9/15 1/2

SWSS 2003 S-tag 7/10 0/3

TOTAL 21/34 2/11

Eddy circulation features can have a large impact on the biology as well as the physics in the

Gulf of Mexico. Cold-core, cyclonic eddies are associated with nutrient enrichment and

increased biological productivity. Whales and other predators are attracted especially to the

boundaries of these eddies where prey are accumulated (Griffin 1999; Biggs et al. 2000).

During the SWSS 2003 WSHC cruise in May/June 2003, the ship track went from the western

Gulf of Mexico toward the east. At the time of the cruise, the western region had no strong eddy

features, but there was a large anticyclonic eddy in close proximity to a strong cyclonic eddy in

the eastern region. The ADCP backscatter signal showed differences between the eastern and

western regions. The backscatter signal at 100 meters had a higher nighttime average in the

eastern region with eddies (days 9-20) than that in the western region without eddies (days 1-8).

Daytime backscatter, represented as the lowest daily signal when migratory animals are in the

DSL, was greatest on days 8-10 of the cruise (Figure 4.9.2).

Scattering layers below the main DSL were observed about 1/4 of the time in the anticyclone

region and about 1/2 of the time in all other regions including that of the cyclonic eddy, the

confluence region between the two eddies, and in the western region with no eddies (Table

4.9.2). Eddy features seemed to have an influence on the main DSL and also on deeper scattering

layers. However, the strongest hydrographic influences on scattering layers were observed as the
137

Figure 4.9.1. Relative backscatter counts shown for Gulf of Mexico slope region (top) and for

the deep basin region (bottom). The horizontal axis represents time, where each

ensemble is a 5 minute average.
138

Figure 4.9.2. Relative backscatter counts recorded by the 38-kHz ADCP for the 100, 600, and

700 m depth bins for the SWSS 2003 WSHC cruise.

Table 4.9.2

Occurrence of Scattering Below the Main DSL (> 650 m) Out of the Number of Possible

Days When in Cyclonic, Anticyclonic, Boundary, or No Feature in the Four

Hydrographic Regions

Cruise Cyclone Anticyclone Confluence Other

SWSS 2002 S-tag 0/1 0/1 3/8

SWSS 2003 WSHC 2/2 1/3 1/1 4/5

SWSS 2003 S-tag 0/3 2/7 0/3

TOTAL 2/6 1/4 3/8 7/16

 100

 600

 700
139

ship crossed the Mississippi River plume on 12 June 2003. There was a sudden change from the

blue water of the anticyclone to surface green water entrapped on top of the cyclone. Moving

into this surface green water coincided with the daytime DSL shoaling to about 250 meters, or

more than 200 meters more shallow than its daytime depth of 450 to 500 meters in the adjacent

blue water. The shoaling to 250 m presumably was caused by increased extinction of light

penetration to deeper waters, caused by an increase in phytoplankton and sediment loads in the

surface green water. At 250 meters in the river plume, the vertically migrating organisms were at

a daytime light levels comparable to 500 meters in the blue water. This light level effect might

also be an explanation for why we see relatively lower backscatter at deeper depth bins when

there is high intensity at shallower bins. The rapid extinction of downwelling irradiance by

phytoplankton and other small particles in the low salinity, green surface water apparently causes

the deep living organisms to prefer shallower depths.
141

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Sociobiology 29: 385-389.

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1708-1711.

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APPENDIX: D-tag/CEE Mitigation Protocol

On 3 June 2003, NOAA Fisheries issued permit #981-1707 to Dr. Peter Tyack of Woods Hole

Oceanographic Institution. This permit authorized the controlled exposure experiments that

would be conducted on the D-tag/CEE cruise, as well as the tagging activities themselves. To

assure compliance with the permit requirements, Dr. Tyack and his science team developed a

protocol for mitigation and monitoring during the seismic playbacks that were to be conducted as

part of the D-tag/CEE cruise. On 4 June 2003 prior to the departure of the cruise, this protocol

was sent to the scientists who would be in charge of science operations on board both the

participating vessels, R/V Maurice Ewing and M/V Kondor Explorer. The protocol is given

below in its entirety.

Protocol for mitigation and monitoring during seismic playbacks on board the MV Kondor

during the DTAG-SW03 WHOI experiment in the Gulf of Mexico

Peter Tyack, PI, Permit Holder

Douglas Nowacek, Mitigation Coordinator, Co-investigator

SAFETY RADIUS

The aim of this protocol is to minimize the possibility that any marine mammal or sea turtle will

be exposed to received sound levels exceeding 180 dB re 1 mPa rms during the emission of

seismic pulses for playback experiments in the Gulf of Mexico. This 180 dB criterion is

consistent with guidelines listed for cetaceans by NMFS (2000) and the specifications issued by

NMFS for the Tyack permit 981-1707-00. A safety radius will be conservatively defined for the

space around an active seismic source that takes into account the possible variability and

complexities in sound transmission caused by refraction, bottom echoes, etc. The area within this

radius should be clear of all cetaceans and sea turtles. Different configurations of seismic arrays

during ramp-up and variation in oceanographic conditions will lead to different radii for the 180

dB zone. The 180 dB zone is estimated to be about 950 m for the full array to be used. This zone

will be fine tuned on the basis of the calibrations made during the engineering test to be

conducted well away from cetacean concentrations before the first playback experiment. In

order to maintain a conservative safety radius in the face of uncertainty and variability of the

sound field, the safety radius will be maintained at 1.5 times the expected 180 dB radius.

Therefore, for the full array, the safety radius will be 1.5 x 950 = 1425 m. We are primarily

sighting animals at the surface, and sound energy is directed downwards, so think of this safety

radius as a cylinder with a top circle radius of the safety radius centered on the airgun array, and

with the cylinder extending down to the seafloor directly below the ship.

PROCEDURE

Engineering Test:

The engineering test will require the Kondor as the source vessel (SV) and the Ewing for making

calibrated acoustic measurements. Both ships should rendezvous at a site decided based upon the

preliminary mitigation procedure below. The engineering test should follow these protocols:

Preliminary mitigation: avoid areas where beaked whales or Kogia have been sighted

The preliminary mitigation procedure involves selecting a site for calibration in an area with low

numbers of cetaceans expected based upon historical sighintgs, and that is far from historical

sightings of beaked whales and Kogia. These species are difficult to sight; their vocalizations are

difficult to detect and identify, and their sensitivity to sound is particularly poorly understood.
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This calibration site should be selected using the GIS plots created by Valeria Teloni using

sightings data collated by Joel Ortega, and measuring distances from possible calibration sites to

the nearest sighting of these species in the database. Ewing and SV should consult together on

choice of site based upon the sighting data and operational logistics.

Phase I: one hour prior to the ramp-up.

The engineering test should only take place in daylight with good sighting conditions. Acoustic

and visual monitoring for turtles and cetaceans will start as soon as the SV gets within an hour of

the suggested start position, in order to ensure that the startup location is free of whales, and that

the monitoring teams are operating smoothly by the time of transmission. It may be useful to run

a track around the planned location for onset of sound transmissions, to help ensure that the area

is clear of marine mammals and sea turtles. However, the ship track must be compatible with

operational requirements of preparation of the sound sources.

There will be three or more visual observers scanning with naked eye and Fujinon 7x50 reticle

binoculars at all times from one hour before until one hour after sound transmissions. If there is

any concern about observer fatigue, and if there are not enough skilled observers to alternate two

teams, there should be a temporary pause in transmissions until the observers are back to par.

The observers will work from a high vantage point. At least one observer must have a clear view

aft towards the airgun array, and one must have a clear view forward. Together, the observers

must be able to cover 360 degrees around the ship. Sighting conditions must be appropriate for

sighting out to the safety radius. The initial safety radius will be taken to be 1425m, centered on

the airgun array. This should be conservative, since it is taken from a 20 gun array that has a

larger total displacement than the Kondor array. The mitigation coordinator (MC) will confirm

this with the airgun operators and with acoustic modelers on board the OV prior to the

engineering test. No sound transmissions should take place if the observers do not believe the

sighting conditions are appropriate.

At least one additional person will monitor underwater sound from a towed array of hydrophones

at all times from one hour before until one hour after sound transmissions. This acoustic monitor

will also visually monitor spectrograms and waveforms of these signals. A continuous recording

will be made of this acoustic record at all times from one hour before until one hour after sound

transmissions. The visual and acoustic monitoring teams will be in constant contact with the MC,

who will be informed of all turtle and cetacean detections in real time, with data on range and

bearing to the animals when available. The MC can also play the role of observer or monitor at

the same time.

The position of the animals will be logged in order to minimize the chances that the ramp-up or

subsequent transmissions will occur in areas with marine mammals close enough to trigger

mitigation. If any cetacean or turtle is detected, the MC will work out any changes needed in the

planned location of the SV for startup. Acoustic and visual monitoring for cetaceans will

continue and ramp-up will not start until after an hour of visual and acoustic monitoring around

the SV. Because of the potential sensitivity of beaked whales or Kogia, if any of these species

are detected during that time, even outside of the security radius, the SV will relocate at least 30

km to find a new area for the calibrations well away from these species.

Phase II: Ramp-up to full array.

The safety radius for sound transmission will be set by the configuration of airguns firing,

adjusted by modeling of propagation based upon the conditions for each playback. Once the

engineering test is completed, these calibrated measurements will be used to fine-tune the 180

dB radius and safety zone for each phase of ramp-up and for the full array.
147

Detections of beaked whales or Kogia sp.

The seismic transmissions will be stopped if any beaked whales or Kogia are detected by visual

or acoustic methods at any distance during sound transmission. If there is a positive detection of

one of these species, the playback experiment will be halted. A new playback will not be started

until the Ewing has moved at least 30 km from the location of the sighting.

Detections of sea turtles, baleen whales, sperm whales or delphinids.

Course alteration

If a marine mammal or sea turtle is detected outside the safety radius and, based on its position

and the relative motion, is likely to enter the safety radius, alternative ship tracks will be plotted

against anticipated mammal or turtle locations. If practical, the vessel's course and/or speed will

be changed in a manner that avoids the marine mammal or sea turtle approaching within the

safety radius while also minimizing the effect to the planned science objectives. The marine

mammal activities and movements relative to the seismic vessel will be closely monitored to

ensure that the marine mammal does not approach within the safety radius. If the mammal or sea

turtle appears likely to enter the safety radius, further mitigative actions will be taken, i.e., either

further course alterations or shutdown of the airguns. If the monitors lose track of a mammal or

sea turtle that might, because of its position and swim direction, have come near the safety

radius, the MC will follow conservative procedures to ensure that the animal would not be

exposed within this radius.

Shutdown procedures

Vessel-based observers using visual aids and acoustical arrays will monitor marine mammals and

sea turtles near the seismic vessel for 60 min prior to start up, during all airgun operations, and

for 60 min after cessation of airgun operations. No airguns will be operated during periods of

darkness or in conditions where visual observers cannot effectively monitor out to the range of

the safety radius. Visual observers will always keep a pair of Fujinon 7x50 reticle binoculars

handy and will always know what reticle indicates the safety zone. The range of any sighting

anywhere near the safety radius will immediately be checked using the reticles.

Airgun operations will be suspended immediately when marine mammals are observed or

otherwise detected within, or about to enter, designated safety zones based on the 180 dB rms

criterion specified by NMFS. The MC will also call for a shutdown if the monitors lose track of

an animal that could come within the safety zone. The shutdown procedure should be

accomplished within a “one shot” period of the determination that a marine mammal is within or

about to enter the safety zone. This means that the observers and acoustic monitor must be in

constant contact with the MC, who must also have the ability to immediately contact the airgun

operators. The observers, monitors, MC and airgun operators should conduct dry run tests of the

procedure to assure that it meets these demanding timing specifications. There should be fallback communication methods available.

Airgun operations will not resume until the marine mammal(s) or sea turtle(s) is/are outside the

safety radius. Once the safety zone is clear of marine mammals or sea turtles, the observers will

advise that seismic surveys can re-commence. The restart decision will be made by the MC. If

the source has shutdown, the following "ramp-up" procedure will be followed.

Ramp-up procedure

A “ramp-up” procedure will be followed when the airgun arrays begin operating after a

specified-duration period without airgun operations. If the MC determines that conditions are

appropriate for restarting transmissions within 5 minutes of the shutdown, the ramp-up will start

at 6 dB lower source level than just before shutdown. If the “no shooting” period lasts more than

5 minutes , ramp-up will begin with the smallest gun in the array that is being used. Guns will be
148

added in a sequence such that the source level of the array will increase in steps not exceeding 6

dB per 5-minute period over a total duration of approximately 20-25 min (4-5 iterations for 9-16

gun arrays 1-2-4-8-16). MC will work out details of this ramp up plan, and will communicate

them to Ewing and Tyack for evaluation one day before the engineering test. Engineering test

should confirm that the planned order of addition of airguns leads to the planned increase in

source level before the first CEE.

Phase III: Post exposure observations

Visual observers and acoustic monitors will make every effort to continue to monitor for marine

mammals for one hour after exposure. These data will facilitate evaluation of potential responses

to the sound transmissions, especially if the ship turns back to recover part of the area covered

during sound transmission.

Protocol for Controlled Exposure Experiments to be conducted after a sperm whale is

tagged.

Phase I: Between “tag on” and one hour prior to the ramp-up.

Radio contact will be kept between the observation vessel the R/V Ewing (OV), and the seismic

source vessel the M/V Kondor (SV). The playback coordinator (PC) on the OV will

communicate to the MC on the SV when the tag is on, and direct the vessel towards a suitable

position at the required distance from the tagged animal. The goal for this advance location of

the SV will be to position it so that the tagged whale(s) are likely to be the closest whales, at a

distance so that the initial RL at the whale is below the goal maximum RL, which will be

reached as the SV approaches the tagged whale(s). The PC and MC during this time should work

out a plan for the SV to pass by the tagged whales being followed by the OV to a closest point of

approach (CPA) specified by the goal maximum received level at the tagged whales.

Acoustic and visual monitoring for turtles and cetaceans will start as soon as the SV gets near the

suggested start position, in order to find a “no whale” area for startup. There will be at least two

visual observers scanning with naked eye and Fujinon 7x50 reticle binoculars at all times from

phase 1 until one hour after sound transmissions. The observers will work from a high vantage

point. At least one observer must have a clear view aft towards the airgun array, and the other

must have a clear view forward. Together, they must be able to cover 360 degrees around the

ship. Sighting conditions must be appropriate for sighting out to the safety radius. At least

one person will monitor underwater sound from a towed array of hydrophones at all times from

phase 1 until one hour after sound transmissions. The acoustic monitor will also visually monitor

spectrograms and waveforms of these signals. A continuous recording will be made of this

acoustic record at all times from phase 1 until one hour after sound transmissions. The visual and

acoustic monitoring teams will be in radio contact with the MC, who will be informed of all

turtles and cetacean detections in real time, with data on range and bearing to the animals when

available. The MC can also play the role of observer or monitor at the same time.

If any cetacean or turtle is detected, the MC will communicate to the PC to work out any changes

needed in the planned location of the SV for startup. This change will aim to both avoid

proximity to any non-focal animals and to keep the required distance to the focal whales. The

position of the animals will be logged in order to plan the starting of the ramp-up in areas with

no detections.

Phase II: One hour prior to the ramp-up.

The MC will receive advance notice from the PC at least one hour before the playback is to

commence. Acoustic and visual monitoring for cetaceans will continue and ramp-up will not
149

start until after an hour of visual and acoustic monitoring around the SV. It may be useful to run

a track around the planned location for onset of sound transmissions, to help ensure that the area

is clear of marine mammals and sea turtles. Because of the potential sensitivity of beaked whales

or Kogia, if any of these species are detected during that time, even outside of the security radius,

the SV will relocate at least 10 km to find a new area for CEE well away from these species.

This distance differs from the Engineering Test in order to keep open the possibility for a large

scale SV relocation that still allows for a CEE to a tagged whale. If there is any concern about

exposure of Kogia or beaked whales, the OV will continue tracking the tagged whales, and use

the follow as a control follow or coda playback. Avoiding by maneuver of the vessel should only

occur with species at lower uncertainty about risk of impacts beyond level B harassment and

which we can continue to track, species such as dolphins or baleen whales (visual) or sperm

whales (acoustic).

Phase III: Ramp-up to full array playback.

The safety radius for sound transmission will be set by the configuration of airguns firing,

adjusted by calibration tests and modeling of propagation based upon the conditions for each

playback.

Detections of beaked whales or Kogia sp.

The seismic transmissions will be stopped if any of this species are detected by visual or acoustic

methods at any distance. If there is a positive detection of one of these species, the playback

experiment will be halted. A new playback will not be started until the SV has navigated at least

10 km from the location of the sighting.

Detections of sea turtles, baleen whales, sperm whales or delphinids.

Course alteration

If a marine mammal is detected outside the safety radius and, based on its position and the

relative motion, is likely to enter the safety radius, alternative ship tracks will be plotted against

anticipated mammal locations. If practical, the vessel's course and/or speed will be changed in a

manner that avoids the marine mammal approaching within the safety radius while also

minimizing the effect to the planned science objectives. The marine mammal activities and

movements relative to the seismic vessel will be closely monitored to ensure that the marine

mammal does not approach within the safety radius. If the mammal appears likely to enter the

safey radius, further mitigative actions will be taken, i.e., either further course alterations or

shutdown of the airguns.

Shutdown procedures

Vessel-based observers using visual aids and acoustical arrays will monitor marine mammals

near the seismic vessel for 60 min prior to start up, during all airgun operations, and for 60 min

after cessation of airgun operations. No airguns will be operated during periods of darkness or in

conditions where visual observers cannot effectively monitor out to the range of the safety

radius. Visual observers will always keep a pair of Fujinon 7x50 reticle binoculars and will

always know what reticle indicates the safety zone. The range of any sighting anywhere near this

radius will immediately be checked using the reticles. Airgun operations will be suspended

immediately when marine mammals are observed or otherwise detected within, or about to enter,

designated safety zones based on the 180 dB criterion specified by NMFS in its permit for

scientific research issued to Tyack. If any marine mammal or sea turtle are sighted within the

safety zone, detailed data must be collected about the incident and Tyack should be contacted as

soon as possible, preferably immediately. The shutdown procedure should be accomplished

within a “one shot” period of the determination that a marine mammal is within or about to enter
150

the safety zone. The observers and airgun operators should conduct dry run tests of the

procedure to assure that it meets these demanding timing specifications.

Airgun operations will not resume until the marine mammal(s) is/are outside the safety radius.

Once the safety zone is clear of marine mammals, the observers will advise that seismic surveys

can re-commence. The restart decision will be made by the MC If the source has shutdown, the

following "ramp-up" procedure will be followed.

Ramp-up procedure

A “ramp-up” procedure will be followed when the airgun arrays begin operating after a

specified-duration period without airgun operations. If the MC determines that conditions are

appropriate for restarting transmissions within 5 minutes of the shutdown, the ramp-up will start

at 6 dB lower source level than just before shutdown. If the “no shooting” period lasts more than

5 minutes , ramp-up will begin with the smallest gun in the array that is being used. Guns will be

added in a sequence such that the source level of the array will increase in steps not exceeding 6

dB per 5-minute period over a total duration of approximately 20-25 min (4-5 iterations for 9-16

gun arrays 1-2-4-8-16).

Improving estimates of range to acoustic detections of marine mammals:

Efforts will be made throughout the cruise to determine the detectable range of vocalizing marine

mammals, to relate received levels on the Seamap array to visually-measured ranges, and to

determine range to acoustic contacts using target-motion analysis. Because there will always be

some uncertainty in the range to an acoustically-tracked animal, the MC will apply conservative

estimates of range, and react appropriately (continue, avoid, or shut-down) as above.

Representative case scenarios for mitigation

Note 1: all scenarios assume that if any animal is detected within the 180 dB range,

shutdown will occur immediately

Note 2: Scenarios assume seismic playback is already underway, see below for preexposure conditions

Delphinids, sperm and baleen whales, and sea turtles

1. Sightings or acoustic detections dead ahead

a. If range can be determined

i. If range is sufficient, use course correction to safely avoid safety zone.

ii. If animals are being tracked, but there is temporary uncertainty as to range

when movement of ship and/or animals would bring them within safety

zone within 5-10 min, either shut down or maintain option to ramp down

to half power if that is sufficient to resolve concerns about animals coming

within safety zone.

b. If range cannot be determined, probably because of acoustic detection (likely to

be within 3 km or so)

i. Assign additional visual observer to watch for surfacings

ii. If no confirmation of range but bearing is still ahead after 5 min, change

course if a new heading can be confidently chosen until range and bearing

are determined

iii. If still no confirmation of range but still ahead after 10 min, then full shut

down until ship passes by animal to the point where the animal is certain

to be outside of the safety radius.

2. Sightings or acoustic detections off forward quarters, i.e., 10 - 900 to port or starboard of

bow
151

a. If animal(s)’ direction of movement is parallel to ship, alter path if necessary to

maintain exposure outside of safety zone, monitor location and continue

experiment

b. If direction of movement is away from ship’s path, monitor and continue

c. If direction of movement is directly towards or on an intersecting path, monitor

and prepare for shutdown

i. Alter ship track accordingly to avoid 180 dB exposure

ii. If visual/acoustic contact is lost for ≥5 min, and observers believe animal

was still on a course from a position where maneuvering is not enough to

eliminate risk of animal coming within safety zone, shutdown until ship

has moved outside of area of risk.

3. Sightings or acoustic detections off stern quarters or astern

a. Monitor locations and continue experiment unless direction of animal(s)

movement is towards the ship; if so, follow 2c.

4. For these species, all rampup to follow protocol above.

Beaked and Kogiid whales – if any confirmed detections, cease all seismic activity and move to

a location ≥10 km away. If it is possible, attempt to restart experiment with pre-exposure

protocol and full ramp-up. Otherwise conduct coda playback or control observations.

Pre-Exposure

If any delphinids, sperm or baleen whales or sea turtles are detected during pre-exposure

observations, i.e., the hour before ramp-up, alter ship’s course to avoid their expected locations

at time of ramp-up. No ramp-up will begin if any of these species are within the safety radius,

set to 1.5 times the range for the 180 dB zone.

If any beaked whales, or Kogia are sighted during the pre-exposure, travel ≥10 km before

starting and adjust start time/location of CEE accordingly.
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