NOAA Technical Memorandum NMFS-SEFSC-455

STOCK ASSESSMENTS OF LOGGERHEAD AND

LEATHERBACK SEA TURTLES

AND

AN ASSESSMENT OF THE IMPACT OF THE PELAGIC LONGLINE

FISHERY ON THE LOGGERHEAD AND LEATHERBACK SEA

TURTLES OF THE WESTERN NORTH ATLANTIC

March 2001

U. S. Department of Commerce

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Southeast Fisheries Science Center

75 Virginia Beach Drive

Miami, FL 33149
NOAA Technical Memorandum NMFS-SEFSC-455

STOCK ASSESSMENTS OF LOGGERHEAD AND LEATHERBACK

SEA TURTLES

AND

AN ASSESMENT OF THE IMPACT OF THE PELIGIC LONGLINE

FISHERY ON THE LOGGERHEAD AND LEATHERBACK SEA

TURTLES OF THE WESTERN NORTH ATLANTIC

U. S. DEPARTMENT OF COMMERCE

Donald L. Evans, Secretary

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION

Scott B. Gudes, Acting Administrator

NATIONAL MARINE FISHERIES SERVICE

William T. Hogarth, Acting Assistant Administrator for Fisheries

March 2001

Unpublished reports are used for documentation and timely communication of preliminary

results, interim reports, or special-purpose information, and have not received complete formal

review, editorial control, or detailed editing.
ii

NOTICE

______________________________________________________________________________

The National Marine Fisheries Service (NMFS) does not approve, recommend or endorse any

proprietary product or material mentioned in this publication. No reference shall be made to

NMFS, or to this publication furnished by NMFS, in any advertising or sales promotion which

would indicate or imply that NMFS approves, recommends or endorses any proprietary product

or proprietary material herein or which has as its purpose any intent to cause directly or

indirectly the advertised product to be used or purchased because of NMFS publication.

______________________________________________________________________________

Correct citation of this report is:

National Marine Fisheries Service Southeast Fisheries Science Center. 2001. Stock

assessments of loggerhead and leatherback sea turtles and an assessment of the impact of

the pelagic longline fishery on the loggerhead and leatherback sea turtles of the Western

North Atlantic. U.S. Department of Commerce NOAA Technical Memorandum NMFSSEFSC-455, 343 pp.

Copies of this report can be obtained from:

National Marine Fisheries Service

Southeast Fisheries Science Center

75 Virginia Beach Drive

Miami, FL 33149

(305) 361-4285

or

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

(703) 605-6000 or (800) 553-6847 (rush orders)

National Marine Fisheries Service Southeast Fisheries Science Center, Division of Protected

Resources and Biodiversity Contribution PRD-00/01-08
iii

STOCK ASSESSMENTS OF LOGGERHEAD AND LEATHERBACK SEA

TURTLES AND AN ASSESSMENT OF THE IMPACT OF THE PELAGIC

LONGLINE FISHERY ON THE LOGGERHEAD AND LEATHERBACK

SEA TURTLES OF THE WESTERN NORTH ATLANTIC

Preface

On September 7, 2000 the National Marine Fisheries Service announced that it was

reinitiating consultation under Section 7 of the Endangered Species Act on pelagic fisheries for

swordfish, sharks, tunas, and billfish. 1 Bycatch of a protected sea turtle species is considered a

take under the Endangered Species Act (PL93-205). On June 30, 2000 NMFS completed a

Biological Opinion on an amendment to the Highly Migratory Pelagic Fisheries Management

Plan that concluded that the continued operation of the pelagic longline fishery was likely to

jeopardize the continued existence of loggerhead and leatherback sea turtles.2

 Since that

Biological Opinion was issued NMFS concluded that further analyses of observer data and

additional population modeling of loggerhead sea turtles was needed to determine more precisely

the impact of the pelagic longline fishery on turtles. 3,4 Hence, the reinitiation of consultation.

The documents that follow constitute the scientific review and synthesis of information

pertaining to the narrowly defined reinitiation of consultation: the impact of the pelagic longline

fishery on loggerhead and leatherback sea turtles The document is in 3 parts, plus 5 appendices.

Part I is a stock assessment of loggerhead sea turtles of the Western North Atlantic. Part II is a

stock assessment of leatherback sea turtles of the Western North Atlantic. Part III is an

assessment of the impact of the pelagic longline fishery on loggerhead and leatherback sea turtles

of the Western North Atlantic.

These documents were prepared by the NMFS Southeast Fisheries Science Center staff

and academic colleagues at Duke University and Dalhousie University. Personnel involved from

the SEFSC include Joanne Braun-McNeill, Lisa Csuzdi, Craig Brown, Jean Cramer, Sheryan

Epperly, Steve Turner, Wendy Teas, Nancy Thompson, Wayne Witzell, Cynthia Yeung, and also

Jeff Schmid under contract from the University or Miami. Our academic colleagues, Ransom

 

1

 NMFS Reinitiates Consultation Under the Endangered Species Act (ESA) on the Pelagic Fisheries for Swordfish,

Sharks, Tunas and Billfish. Press release from Bruce C. Morehead, Acting Director, Office of Sustainable Fisheries,

National Marine Fisheries Service, Silver Spring, Md., September 7, 2000, 1 pp.

2

 Endangered Species Act - Section 7 Consultation Biological Opinion. Reinitiation of Consultation on the Atlantic

Pelagic Fisheries for Swordfish, Tuna, Shark and Billfish in the U.S. Exclusive Economic Zone (EEZ): Proposed

Rule to Implement a Regulatory Amendment to the Highly Migratory Species Fishery Management Plan; Reduction

of Bycatch and Incidental Catch in the Atlantic Pelagic Longline Fishery, 118 pp. Consultation conducted by

National Marine Fisheries Service, Office of Protected Resources, Silver Spring, Md., June 30, 2000.

3

 Memorandum from Bruce Morehead, Acting Director, Office of Sustainable Fisheries to Donald R. Knowles,

Director, Office of Protected Resources, National Marine Fisheries Service, Silver Spring, Md., September 7, 2000.

4

 Memorandum from Donald R. Knowles, Director, Office of Protected Resources to Bruce Morehead, Acting

Director, Office of Sustainable Fisheries, National Marine Fisheries Service, Silver Spring, Md., September 7, 2000.
iv

Myers, Keith Bowen, and Leah Gerber from Dalhousie University and Larry Crowder and

Melissa Snover from Duke University, also recipients of a Pew Charitable Trust Grant for a

Comprehensive Study of the Ecological Impacts of the Worldwide Pelagic Longline Industry,

made significant contributions to the quantitative analyses and we are very grateful for their

collaboration. We appreciate the reviews of the stock definition sections on loggerheads and

leatherbacks by Brian Bowen, University of Florida, and Peter Dutton, National Marine Fisheries

Service Southwest Fisheries Science Center, respectively, and the comments of the NMFS

Center of Independent Experts reviewers Robert Mohn, Ian Poiner, and YouGan Wang on the

entire document. We also wish to acknowledge all the unpublished data used herein which were

contributed by many researchers, especially the coordinators and volunteers of the nesting beach

surveys and the sea turtle stranding and salvage network and the contributors to the Cooperative

Marine Turtle Tagging Program.

Nancy B. Thompson and Sheryan P. Epperly
v

Table of Contents

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

Part I. Stock Assessment of Loggerhead Sea Turtles of the Western North Atlantic... 3

Part II. Stock Assessment of Leatherback Sea Turtles of the Western North Atlantic.. 67

Part III. Assessment of the Impact of the Pelagic Longline Fishery on Loggerhead and

Leatherback Sea Turtles of the Western North Atlantic..................................... 105

Appendix 1. The Meta-Analysis of Population Trends of Loggerhead and Leatherback

....................................................................................................... 227

Appendix 2. Summary of Observed, Estimated, Incidental, Lethal, and Strandings Take

Levels, Sea Turtle Life Stage, Geographic Region of Activity, and Reference for

Permitted and Non-Permitted Specific and Generalized Activities Impacting Sea Turtles

in the U.S. Atlantic, Caribbean, and Gulf of Mexico........................................ 245

Appendix 3. Observed Sea Turtle Captures in the U.S. Atlantic Pelagic Longline

Fishery, 1999-2000................................................................................ 298

Appendix 4. Documentation for F/PR Review of Post Hooking Mortality............... 312

Appendix 5. Output from GLM Week/Square Analysis from Logbook and Observer

Data................................................................................................. 336
1

Executive Summary

Along the North American coast, the loggerhead sea turtle population structure is described by

nesting subpopulations consisting of a northern subpopulation, which extends from northeastern

Florida coast northward, a south Florida subpopulation from the central Florida east coast

southward, a Dry Tortugas subpopulation, a Florida Panhandle subpopulation, and a Yucat ́n

subpopulation in Mexico. Nesting trends are only available for the northern and south Florida

subpopulations.

Trend analyses of the number of nests from sampled beaches from these two subpopulations

show that from 1978-1990, the northern subpopulation has been stable at best and possibly

declining (less than 5% per year). From 1990 to the present the number of nests has been

increasing at 2.8-2.9% annually. Over these same periods, the Florida subpopulation had been

increasing at 5.3-5.4% per year, but since 1990 this rate appears to be slowing (3.9-4.2%).

Authorized takes of turtles continue and include several fisheries and other anthropogenic

sources. For the longline fishery, it is estimated that between 293 to 2439 loggerhead turtles are

taken annually based on observer data from 1992-1999. If 50% of these animals are killed then

the mortality from this fishery is estimated to be from 147 to 1220 per year.

The U.S. and 26 other nations participate in longline fishing throughout the western North

Atlantic Ocean and the relative proportion of total hooks fished by the U.S. fleet is small as

compared with the foreign fleets. However, the relative efficiency of the U.S. fleet as compared

with the foreign fleets is high but how this translates into catches of non-target species is not

known but clearly turtles are bycatch in the foreign fleets.

To evaluate the magnitude of change in pelagic survivorship (the life history stage longline

fishing impacts) required for the northern nesting subpopulation to meet recovery criteria, a

female only model was developed based on four different stage length scenarios and applying

three different population growth rates with three different sex ratios all derived from empirical

studies.

Modeling results indicate that the population growth rate is most sensitive to survivorship in the

life history stages with the longest durations. Cumulatively, these are the juvenile stages.

Efforts to maximize the survivorship in all of the juvenile life history stages would include

evaluating takes from all sources. In particular it is noted that large juvenile turtles are yet to be

excluded from current Turtle Excluder Devices.

It is unlikely that any loggerhead nesting subpopulation under the status quo will be extirpated

over the next few years. It is recommended that actions to reduce juvenile mortality be identified

through research and implemented as soon as feasible.

Genetic analyses indicate that female leatherback turtles nesting in St.Croix/Puerto Rico and

those nesting in Trinidad differ from each other and from turtles nesting in Florida, French

Guiana/Suriname and along the South African Indian Ocean coast. Turtles nesting in Florida,

French Guiana/Suriname and South Africa cannot be distinguished at this time with mtDNA.
2

The largest known nesting aggregation of the leatherback turtles in the western North Atlantic

Ocean occurs in French Guiana. This may be the largest nesting aggregation of leatherback

turtles in the world and has been declining at about 15% per year since 1987. From the period

1979-1986, the number of nests was increasing at about 15% annually.

The number of nests in Florida and the U.S. Caribbean has been increasing at about 10.3% and

7.5%, respectively, per year since the early 1980’s but the magnitude of nesting is much smaller

than that along the French Guiana coast.

Based on observer data from 1992 to 1999 the takes of leatherback turtles from the U.S. longline

fishery range from 308 to 1054 annually. If 50% of these turtles die, then the mortality ranges

from 154 to 527 per year.

It has been estimated that the U.S. commercial shrimp trawl fishery takes 650 leatherback turtles

annually.

It is expected that longline fishing would not be able to discriminate among turtles by nesting

beach origin. Assuming that Atlantic Ocean subpopulations exhibit the same life history

characteristics, then it is expected that if longline fishing were causing the declines in French

Guiana, declines would be measured in other nesting subpopulations.

While the longline fishery, both U.S. and foreign, and the U.S. shrimp trawl fishery may not be

the immediate cause in declines in nesting in French Guiana, they could be contributing to these

declines.

Four hypotheses are offered to determine the cause of the decline in nesting in French Guiana

and all suggest that activities off the coast, such as fishing, likely are causing the decline in

nesting. The causes for the observed decline must be identified and actions pursued immediately

if the declines are not part of a natural nesting cycle.

It is recommended that research begin immediately to identify and quantify the rate of mortality

from the longline fishery, both U.S. and foreign, as well as mortality rates from other fisheries.

A mechanism to initiate discussions with foreign nations relative to fishing activities outside of

U.S. waters needs to be immediately identified.
PART I

STOCK ASSESSMENT OF

LOGGERHEAD SEA TURTLES OF

THE WESTERN NORTH ATLANTIC

Sheryan P. Epperly

Melissa L. Snover

Joanne Braun-McNeill

Wayne N. Witzell

Craig A. Brown

Lisa A. Csuzdi

Wendy G. Teas

Larry B. Crowder

Ransom A. Myers
4

Table of Contents

PART I. STOCK ASSESSMENT OF LOGGERHEAD SEA TURTLES OF THE

WESTERN NORTH ATLANTIC............................................................................................... 5

Stock Definition.............................................................................................................................5

Status and Trends..........................................................................................................................9

Nesting beaches............................................................................................................................................................9

Dry Tortugas .............................................................................................................................................................9

Nesting Trends....................................................................................................................................................... 10

In-water Surveys ........................................................................................................................................................ 11

Trends: Southeast Area Monitoring and Assessment Program - (SEAMAP)................................................... 11

Stock Assessment.........................................................................................................................14

Vital Rates.................................................................................................................................................................. 15

Duration of Stages................................................................................................................................................. 15

Size-at-Stage .......................................................................................................................................................... 17

Sex Ratios.............................................................................................................................................................. 17

Survival Rates........................................................................................................................................................ 19

Population Models..................................................................................................................................................... 21

Elasticity of Stages................................................................................................................................................ 21

Sex Ratios.............................................................................................................................................................. 22

Population Projection............................................................................................................................................ 22

Impacts on the Populations .........................................................................................................25

Recent Stranding Events and Trends........................................................................................................................ 25

Fate of Dead Turtles .................................................................................................................................................. 26

Anthropogenic Impacts............................................................................................................................................. 26

Pelagic longline fisheries ...................................................................................................................................... 26

Trawls..................................................................................................................................................................... 26

Gill nets.................................................................................................................................................................. 27

Hook and line......................................................................................................................................................... 28

Power plants........................................................................................................................................................... 29

Pound Nets............................................................................................................................................................. 29

Other Fisheries....................................................................................................................................................... 29

Marine Debris........................................................................................................................................................ 30

Discussion....................................................................................................................................30

Literature Cited...........................................................................................................................31
5

PART I. STOCK ASSESSMENT OF LOGGERHEAD SEA TURTLES OF

THE WESTERN NORTH ATLANTIC

The Turtle Expert Working Group, established in 1995 by the Southeast Fisheries

Science Center at the behest of the National Marine Fisheries Service, has published two reports

(1998, 2000) which, in part, concern the status and condition of the loggerhead sea turtle stocks

of the Western North Atlantic. Herein we do not attempt to duplicate material in those reports,

but instead provide updated information acquired since the preparation of the last report. Thus,

this document is to be used in conjunction with the two TEWG reports.

Stock Definition

Sea turtles have complex migratory behaviors and gender-specific dispersal that must be

considered in defining management units. Sexual differences in dispersal or migratory behaviors

may lead to different estimates of population structure calculated with mitochondrial (mtDNA)

and nuclear (nDNA) DNA (Avise 1995). Bowen (1997) points out that these results are not

necessarily conflicting but reflect the expected consequence of sex-specific dispersal. Assays of

both biparental (nDNA) and uniparental (mtDNA) lineages are needed to understand the

complex stock structure of migratory animals such as sea turtles. Either used in isolation can be

misleading, especially conclusions based on nDNA alone, where in the case of sea turtles one

might conclude that recruitment of females from other reproductive populations would counter

the depletion of a rookery.

Assays of mtDNA illuminate the stock structure of the female lineages that are essential

to reproduction and species recovery. mtDNA is used as a genetic tag to show a behavioral

aspect of sea turtle life history - natal homing of egg-laying females - not to indicate important

genetic differences between nesting colonies of sea turtles. Results of maternally-inherited

mtDNA studies of sea turtles support the hypothesis of natal homing region (Encalada et al.

1996, Encalada et al. 1998, Bass 1999, Dutton et al. 1999). Each nesting assemblage represents

a distinct reproductive population, regardless of the nDNA findings, because the production of

progeny depends on female nesting success. Thus, should a nesting assemblage be depleted,

regional dispersal will not be sufficient to replenish the depleted assemblage over ecological time

scales germane to immediate management issues (Avise 1995), a consequence with both

population and ecological implications. Based on mtDNA results available at the time (Bowen

et al. 1993, Bowen 1995, Encalada et al. 1998), the Turtle Expert Working Group (1998, 2000)

recognized at least 4 genetically distinct loggerhead (Caretta caretta) nesting subpopulations in

the western North Atlantic and suggested that they be considered independent demographically,

consistent with the definition of a distinct vertebrate population segment (59 FR 65884-65885,

December 21, 1994; 61 FR 4722-4725 February 7, 1996) and of a management unit (MU)

(Moritz, 1994a, b). Recent fine-scale analysis of mtDNA data from Florida rookeries indicate

that population separations begin to appear between nesting beaches separated by more than 100

km of coastline that does not host nesting (Francisco et al. 20001) and tagging studies are

 

1

 Francisco, A.M., A.L. Bass, K.A. Bjorndal, A.B. Bolten, R. Reardon, M. Lamont, Y. Anderson, J. Foote, and B.W.

Bowen. 2000. Stock structure and nesting site fidelity in Florida loggerhead turtles (Caretta caretta) resolved with
6

consistent with this result (Richardson 1982, Ehrhart 19792, LeBuff 1990, CMTTP3). Nest site

relocations greater than 100 km occur, but generally are rare (CMTTP4, LeBuff 1974, Ehrhart

19795, Bjorndal et al. 1983, LeBuff 1990). However, there are a number of reports of recaptured

animals nesting on Little Cumberland Island, Georgia that were originally tagged in Melbourne,

Florida (J. Richardson personal communication6). Based on these results there are at least four

management units (MU) in the southeastern U.S: (1) Florida Panhandle, (2) southern Florida, (3)

Amelia Island (Volusia County, Florida) and northward, and (4) the Dry Tortugas. The nesting

subpopulation on the Yucat<n Peninsula is a fifth MU identified in the Western North Atlantic

(Encalada et al. 1998) and there may be more. Assemblages throughout the greater Caribbean

and those in the Eastern North Atlantic (e.g., Cape Verde Islands, Senegal, and Morocco;

Sternberg 1981) been not been assayed, but sampling has begun in the Cape Verde Islands where

a significant numbers of turtles still nest7.

The area between Cape Canaveral and Amelia Island has intermediate genotype

frequencies that indicate another management unit by some criteria (Francisco et al. 19998).

Loggerheads nesting from Amelia Island to North Carolina are indistinguishable with mtDNA,

but this means only that there is not the resolution to detect any differences, which suggests that

the area was colonized by a small number of females after the last (Wisconsin) glacial epoch.

Given the recent colonization northward, it is not surprising that there is insufficient genetic

diversity for an assessment of stock structure. There may be different units contained in this one

management unit as there are significant distances with little or no nesting between rookeries

throughout the area and, based on the 100 km yardstick, likely are significantly isolated as to be

 

mtDNA sequences. Unpublished Manuscript . Department of Fisheries and Aquatic Sciences, University of Florida,

Gainesville, 23 pp.

2

Ehrhart, L.M. 1979. A survey of marine turtle nesting at the Kennedy Space Center, Cape Canaveral Air Force

Station, North Brevard County, Florida. Unpublished report by the University of Central Florida, Orlando, to the

Florida Department of Natural Resources, Division of Marine Resouces, St. Petersburg, Fla., 122 pp.

3

 Unpublished Data. The Cooperative Marine Turtle Program was established by NMFS in 1980 to centralize the

tagging programs among sea turtle researchers, distribute tags, manage tagging data, and facilitate exchange of tag

information. Since 1999 the CMTTP has been managed by the Archie Carr Center for Sea Turtle Research at the

University of Florida, Gainesville.

4

Ibid.

5

Ehrhart, L.M. 1979. A survey of marine turtle nesting at the Kennedy Space Center, Cape Canaveral Air Force

Station, North Brevard County, Florida. Unpublished report by the University of Central Florida, Orlando to the

Florida Department of Natural Resources, Division of Marine Resouces, St. Petersburg, Fla., 122 pp.

6

 Jim Richardson, University of Georgia, Athens. Personal Communication (Phone) to Sheryan Epperly, National

Marine Fisheries Service, SEFSC, Miami, Fla., January 30, 2001.

7

 Luis Felipe López Jurado, University of Las Palmas, Cape Verde Islands, Personal Communication (E-Mail) to

CTURTLE Listserver (http://www.lists.ufl.edu/archives/cturtle.html), January 14, 2000.

8

 Francisco, A.M., A.L. Bass, and B.W. Bowen. 1999. Genetic characterization of loggerhead turtles (Caretta

caretta) nesting in Volusia County. Unpublished report to Florida Department of Environmental Protection..

Department of Fisheries and Aquatic Sciences, University of Florida, Gainesville, 11 pp.
7

MUs. We are not identifying subdivisions of the northern subpopulation as separate MUs at this

time, however, there is some risk in this decision. Avise (1995) argues that a combination of

genetics and demographics needs to be used to define population structure for conservation.

Failure to reject the null hypothesis (panmixia) based solely on genetic parameters can lead to

incorrect management decisions and managers risk losing local populations (Taylor and Dizon

1996, 1999). The identification of putative management units within the currently defined

northern subpopulation as well as the entire issue of loggerhead management units is something

that a recovery team needs to address immediately.

Nuclear DNA contains the important genes for adaptation and long-term survival. Since

it is biparentally inherited it provides information on the behavior of male sea turtles that is not

available from mtDNA. In 1999 NMFS contracted the Department of Fisheries and Aquatic

Sciences, University of Florida, to analyze nDNA data from loggerhead rookeries in the western

Atlantic. A final report is due soon and the results will be presented at the upcoming meeting of

the American Society of Ichthyologists and Herpetologists in July 2001. Very preliminary

results indicate that population structuring defined by nDNA (microsatellite) assays is much

lower in the southeast U.S. than found in the mtDNA studies9. The implication is that males are

a conduit for gene flow between the egg-laying populations defined by female site fidelity, but

the amount of male-mediated gene flow is not yet determined. Three points need to be made: (1)

The population structuring observed with nDNA, while lower than observed with mtDNA, may

still be significant across the southeast U.S., supporting the subdivision into multiple stocks, (2)

A little male-mediated gene flow between nesting colonies means that concerns about genetic

diversity within nesting populations may be less pressing and small nesting populations are less

likely to suffer the effects of inbreeding, and (3) These conclusions about nDNA of western

North Atlantic loggerhead sea turtles are extremely preliminary and further analysis of the data is

ongoing. The results of a study on loggerheads in the eastern Mediterranean demonstrated there

was low male-mediated gene flow between nesting sites and that there was genetic

substructuring due to the high precision of natal homing by nesting females (Schroth et al. 1996).

These authors concluded that in order to preserve the genetic diversity of the Caretta

metapopulation in the eastern Mediterranean one needed to preserve individual nesting sites.

Foraging grounds contain cohorts from nesting colonies from throughout the Western

North Atlantic (see Table 10 in TEWG 2000). Since the preparation of the last TEWG report,

three more reports have provided additional genetic data on the foraging ground composition of

loggerhead sea turtles. The Florida Bay loggerhead foraging population is composed primarily

of individuals from the South Florida subpopulation (84%) with some contribution observed

from the northern subpopulation (8%), the Florida Panhandle subpopulation (<1%), and the

Yucat<n subpopulation (8%) (Bass et al. 199810). Additional samples from North Carolina’s

 

9

 Discussions (E-Mail) between Brian Bowen (contractor, University of Florida, Gainesville) and Sheryan Epperly

(contract technical monitor, National Marine Fisheries Services, SEFSC, Miami, Fla.) and analyses by Alicia

Francisco (graduate student of Dr. Bowen), November 7, 2000, November 14, 2000, December 17, 2000, and

December 29, 2000.

10 Bass, A.L., M. Clinton, and B.W. Bowen. 1998. Loggerhead turtles (Caretta caretta) in Florida Bay: an

assessment of origin based on genetic markers. Unpublished report to Florida Department of Environmental

Protection. Department of Fisheries and Aquatic Sciences, University of Florida, Gainesville, Fla., 5 pp.
8

Pamlico-Albemarle Estuarine Complex revealed that the South Florida subpopulation dominated

(64%) there (Bass et al. 200011). The northern subpopulation contributed 30% and the remaining

were divided among Mexico (5%) and possibly Brazil (<1%). The authors also found significant

temporal variation in the relative contributions of the subpopulations among the 3 yrs.

In 1998 NMFS contracted the analysis of samples collected from stranded animals

throughout the southeastern U.S. and Gulf of Mexico12. Those results (Bass et al. 199913) (Fig.

1) indicate that the relatively large South Florida subpopulation dominates everywhere, but more

so in the Gulf of Mexico where in the western Gulf it accounts for 83% of the animals. In

Florida (geographic distribution of sampling unknown), the contribution of the South Florida

subpopulation was 73%. In Georgia, its contribution was 73%, also (Ibid.). The contribution of

this subpopulation decreased to 65-66% off the Carolinas and decreases further north of Cape

Hatteras (46%). In the northernmost area sampled, Virginia, the northern subpopulation

accounted for 46% of the animals. It contributes 25-28% off the Carolinas, 24% off Georgia,

and off Florida east and west coast combined, contributes 20%. The contribution of the northern

subpopulation to western Gulf cohorts is but 10%. The Yucat<n subpopulation’s contribution

throughout the region ranged from 6-9%, except off Georgia where the contribution was but 3%.

The Florida Panhandle subpopulation was not included as a possible contributor in these

analyses because it is unlikely that its contribution could be detected against the hundreds of

individuals assayed from South Florida; the inclusion of populations that contribute less than 1%

in the overall nesting effort generates overestimates of contribution and can compromise the

accuracy of estimates made for the other source populations.

Other sources of information indicate structuring of the Western Atlantic nesting

assemblages of loggerhead sea turtles. Results of a study on carapace eipbionts on turtles nesting

along the Atlantic Coast of the U.S. indicated there were two populations of turtles, divided at

northeast Florida (Cape Canaveral to Daytona Beach) (Caine 1986). The epibiont community

included a number of long-lived sessile organisms likely unaffected by short term immigration or

emigration. The low amount of overlap in the epibiont communities (4.2-7.5%) indicated that

turtles were spending time in different foraging environments. Certain epibionts of the southern

population of nesting turtles were of Caribbean origin whereas some of the epibionts of the

northern nesting turtles were indicative of the Sargasso Sea. Based on recent satellite telemetry

studies and on returns of tags, both applied at nesting beaches, non-nesting adult females from

the South Florida subpopulation are distributed throughout the Bahamas, Greater Antilles, Cuba,

Yucatán, eastern Gulf of Mexico, and southern Florida (Meylan 1982, Meylan et al. 1983,

 

11 Bass, A.L., S.P. Epperly, J. Braun-McNeill, and A. Francisco. 2000. Temporal variation in the composition of a

loggerhead turtle (Caretta caretta) developmental habitat. Unpublished manuscript. Department of Fisheries and

Aquatic Sciences, University of Florida, Gainesville, Fla., 26 pp.

12 The Sea Turtle Stranding and Salvage Network is a cooperative endeavor between NMFS, other federal agencies,

the states, many academic and private entities, and innumerable volunteers. Data are archived at the National Marine

Fisheries Service Southeast Fisheries Science Center in Miami, Fla.

13 Bass, A.L., S-M. Chow, and B.W. Bowen. 1999. Final report for project titled: genetic identities of loggerhead

turtles stranded in the Southeast United States. Unpublished report to National Marine Fisheries Service, order

number 40AANF809090. Department of Fisheries and Aquatic Sciences, University of Florida, Gainesville, Fla., 11

pp.
9

http://cccturtle.org/sat1.htm) whereas non-nesting adult females from the northern subpopulation

appear to occur almost exclusively along the east coast of the U.S. (http://cccturtle.org/sat1.htm);

only one northern subpopulation mature female has been reported to enter the eastern Gulf of

Mexico (Bell and Richardson 1978), and none have been reported from international waters

(CMTTP3). Limited tagging data suggest those adult females nesting in the Gulf of Mexico that

are not part of the South Florida subpopulation remain in the Gulf of Mexico, including on

feeding grounds off Yucatán (Meylan 1982, http://cccturtle.org/sat1.htm). Annual nesting at

rookeries within a subpopulation’s nesting range is correlated, but nesting among subpopulations

is not (TEWG 2000).

Status and Trends

Nesting beaches

The preparation of the TEWG reports (1998, 2000) pre-dated the identification of the Dry

Tortugas as a management unit. The reader is referred to the TEWG reports for discussions on

the other subpopulations.

Dry Tortugas

Sea turtle nesting in Dry Tortugas National Park is the highest in all of Monroe County,

which encompasses all of the Florida Keys (Reardon 200014) (Fig. 2). The second highest

productive nesting area in the Florida Keys is the Marquesas Keys (Florida Fish and Wildlife

Conservation Commission 200015), 47 miles east of the Dry Tortugas. The genetic affinity for

individuals in the Marquesas Keys as well as the rest of the Florida Keys has yet to be assayed.

The Dry Tortugas is a group of seven islands with accompanying marine habitats, 70 miles (113

km) west of Key West, Florida. Since 1995 the beaches of all 7 islands were patrolled daily from

early April through late October. The full extent and status of the Dry Tortugas subpopulation is

unknown at this time. Two of the seven islands, East Key and Loggerhead Key, are host to 90%

of all nesting activity observed in the Park (Reardon 200014). In the early 1980’s a tagging study

was conducted on the nesting turtles of East Island and the nesting population was estimated at

40 individuals (Dawson 198516). Nesters ranged from 78.5 to 99.0 cm straight carapace length

with a mean length of 90.4 cm3 (Fig. 3). The range in annual number of recorded nests for the

period 1995-2000 was 190-269 with a mean of 217 nests/year (Table 1). The average clutch size

has ranged from 98-105 eggs annually with an incubation time ranging from 51.0 to 54.6 days

 

14 Reardon, R.T. 2000. Annual Report - 2000 Season. Dry Tortugas National Park Sea Turtle Monitoring Program,

Monroe County, Florida. Unpublished report. Annual report by Florida International University to Dry Tortugas

National Park, Miami, Fla., 49 pp.

15 Florida Fish and Wildlife Conservation Commission. 2000. Statewide Nesting Beach Survey Program Database.

Reported Nesting Activity of the Loggerhead Turtle, Caretta caretta, in Florida, 1993-1999. Unpublished Report.

Florida Marine Research Institute, St. Petersburg, Fla., 8 May 2000, 26 pp.

16 Dawson, R.H. 1985. Project completion report: results of the 1985 sea turtle nesting survey at Fort Jefferson

National Monument, Dry Tortugas, Florida. Prepared by the National Park Service Southeast Regional Office,

Atlanta, Georgia for USFWS Endangered Species Field Station, Jacksonville, Fla., 49 pp.
10

(average 52.9 days). Eighty percent of loggerhead clutches were inventoried and hatching

success ranged from 72.3 to 82% annually with an average of 77.1%.

Due to the relative isolation and lack of fresh water these islands are without mammalian

nest predators but about 10% of the nests are lost annually to erosion14. Local potential threats to

nesting in the Park is mainly limited to visitation; human usage needs to be monitored

particularly during the nesting season to limit impacts to nests (Reardon 200014, Dawson 198516).

Within the Park commercial fishing is prohibited and recreational fishing is limited. Presently

the surrounding marine habitats are being considered for a designation as an Ecological Reserve.

Although the proposed Tortugas Ecological Reserve concentrates on protecting the coral reef

ecosystem and fish stocks, resident turtles and migratory nesters should benefit also due to the

intended expansion of “no take” zones (U.S. Department of Commerce17).

Nesting Trends

Previous estimates of nesting trends for the northern subpopulation prior to the

implementation of TEDs are a decline of 3 percent per year (λ=0.97) (Frazer 1983b) for Little

Cumberland Island, Georgia and a decline of 5% per year (λ=0.95) (TEWG 1998) for South

Carolina. It is possible that these two beaches are not representative of the overall subpopulation

trend as Little Cumberland Island is known to be a highly erosional beach and nesting at Cape

Island, the largest rookery in South Carolina (and in the northern subpopulation), may have been

affected by raccoon predation control in the first half of the 20th century (S. Murphy personal

communication18). For the south Florida population, Hutchinson Island, Florida was increasing at

2.2 percent per year prior to the implementation of TEDs (TEWG 1998).

Regression analysis of individual beaches in the northern subpopulation revealed both

significantly positive and negative trends on some of the beaches. To assess these trends

simultaneously, nesting data from selected beaches were used in a meta-analysis to estimate

changes in nesting activity over time for the northern subpopulation and the South Florida

subpopulation (Appendix 1). The data were limited to sites where surveys were believed to have

been relatively constant over time. It is an unweighted analysis and does not consider the

beaches’ relative contribution to the total nesting activity of the subpopulation and must be

interpreted with some caution. The analysis treats nesting beaches as random samples from the

total. It is necessary to have information on relative abundance in each nesting site in order to

obtain an unbiased overall trend for the populations as a whole.

The pre-1990 northern subpopulation growth rate calculated in the meta-analysis varied,

depending on the statistical assumptions one makes, from not significantly different from r = 0.0

or λ = 1.0 (r=ln(λ) (r = -0.026, SE = 0.105) to a value (r = -0.030, SE = 0.012) similar to the rate

reported previously for Little Cumberland Island. After 1990, the analysis indicates an

 

17 U.S. Department of Commerce. 2000. Strategy for stewardship: Tortugas Ecological Reserve. Final Supplemental

Impact Statement/Final Supplemental Management Plan. National Oceanic and Atmospheric Administration,

Washington, DC., 310 pp.

18 Sally Murphy, South Carolina Marine Resources Department, Charleston, S.C. Personal Communication (EMail) to Sheryan Epperly, National Marine Fisheries Service, SEFSC, Miami, Fla., October 4, 2000.
11

increasing trend of 2.8-2.9% per year. These results should represent the best-case scenario as

the effect of Cape Island nesting activity is dampened in the unweighted analysis.

For the south Florida subpopulation, r = 0.054-0.055 (SE = 0.022, 0.014), and it was

increasing at 5.3-5.4% per year 1979-1989. Although the subpopulation has been increasing

since 1979, the meta-analysis of nesting trends indicates a slowing in the rate of that increase to

3.9-4.2% per year after 1989, but this is not significantly different from the pre-1990 rate. An

important caveat for population trends analysis based on nesting beach data is that this may

reflect trends in adult nesting females, but it may not reflect overall population growth rates well.

Adult nesting females often account for less that 1% of total population numbers.

In-water Surveys

Fishery independent, in-water studies of sea turtles have been carried out at multiple sites

in the Gulf and U.S. Atlantic with varying goals and target species. To date, NMFS has not been

able to use the results of these studies to determine trends of in-water sea turtle populations (see

discussion in TEWG 2000). In March 2000 NMFS sponsored a workshop to determine the

feasibility of using sea turtle catch and survey methods to determine relative population

abundance and population trends and to train participants in analyzing their data for this purpose

(Bjorndal and Bolten 2000). The participants concluded that although the duration to detect

trends in relative abundance differed among studies, all techniques reviewed appeared to be

feasible. However, many have not been standardized over a long enough period to analyze for

trends. Furthermore the statistical power varied among the studies. A fishery-dependent trawl

survey examined was an exception – it did not appear to be a feasible method - but those data

were not examined with non-parametric statistics. Epperly (in Bjorndal and Bolten 2000) clearly

demonstrated the value of using non-parametric statistical models in the analysis of data sets

with a large number of zero catches, which is typical of random sampling for sea turtles. As

sufficient data are accumulated we encourage researchers to begin publishing the results of their

studies to elucidate trends in abundance of non-nesting turtles.

Trends: Southeast Area Monitoring and Assessment Program - (SEAMAP)

In 1986, the South Carolina Marine Resources Department initiated a NMFS-funded

fishery-independent trawl survey off the southeastern U.S. states to assess finfish populations

(SCMRD 2000). The survey includes ocean waters 15-60 ft (4.6-18.3 m) deep, from Cape

Hatteras to Cape Canaveral (Fig. 4). In 1990 the survey was standardized and stations were

chosen based on a stratified random design and once established were fixed and trawled

repetitively over the years. The survey design is to make 78 tows/season in nearshore strata in

spring, summer, and fall and 27 and 16 tows in offshore strata in spring and fall, respectively.

Over the 11 yr period of 1990-2000, only 10 stations have been missed. Paired 75 ft (22.9 m)

high rise trawls (Mongoose-Falcon nets), originally of 1-7/8 in (4.8 cm) stretch mesh and in later

years of 1-5/8 in (4.1 cm) mesh, without turtle excluder devices have been used throughout the

study, and with very few exceptions tow duration for each haul has been 20 min. during daylight

hours. Sea turtles infrequently are captured. The survey now is more than a decade old and is

analyzed for trends in loggerhead sea turtle abundance for the first time.
12

Methods

The process of calculating the indices of abundance from this data involves the

standardization of yearly changes in bycatch rate, accounting for the influence of those factors

that have a significant influence. Factors which were considered as possible influences on

bycatch rates included year, season, latitude, and precipitation state during the tow (PRECIP,

rated as none, light rain, or moderate rain), surface salinity, bottom salinity, air temperature,

surface water temperature, bottom water temperature, barometric pressure, time at the start of the

tow, water depth at the start of the tow, and vectors of wind velocity from the north

(NORTWIND, typically along shore) and from the west (WESTWIND, typically off shore).

Effort units were defined as the individual tows, which as stated previously were nearly all 20

minutes in duration.

The areas defined for the survey are shown in Figure 4. Area strata were categorized as

either INNER (nearer to shore) or OUTER (further from shore). Few turtles were caught in the

OUTER strata; when this did occur, it was usually during the spring season. Preliminary

examination of the data suggested that this OUTER turtle bycatch during the spring might result

from colder temperatures in the INNER strata during that year-season, with turtles consequently

staying in the deeper waters. Furthermore, turtle migration takes place during the spring season,

which may result in bycatch levels which are subject to local migration patterns rather than

reflective of abundance. For these reasons, the analysis data set was restricted to the INNER

area strata and to the summer and fall seasons. The observed loggerhead turtle yearly bycatch

rates are shown in Table 2 and Figure 5.

The Lo method (Lo et al. 1992) was used to develop standardized indices; with that

method separate analyses are conducted of the positive bycatch rates and the proportions of the

observed tows on which turtles were caught. This has been used previously for analyses of

bluefin tuna catch rates on rod and reel (Ortiz et al. 1999, Turner et al. 1999, Brown et al. 1999),

catch rates which are similar to the turtle bycatch rates from the SEAMAP survey data in that

they can be extremely low, particularly for the largest size classes of bluefin tuna. For those

bluefin tuna analyses, a delta-lognormal model approach was used; this used a delta distribution

with an assumed binomial error distribution for the proportion of positive observations (trips),

and assumed a lognormal error distribution for the catch rates on successful trips. More recent

analyses for bluefin tuna rod and reel catch rates (Brown in prep) and yellowfin tuna longline

catch rates (González Ania et al. 2001) used a delta-Poisson model approach, differing from the

delta-lognormal approach in that a Poisson error distribution is assumed for the catches on

successful trips. The delta-Poisson model approach was used for the analyses of the turtle

bycatch rates.

Parameterization of the model was accomplished using a Generalized Linear Model

(GLM) structure: The proportion of tows with loggerhead bycatch (i.e., positive observations)

per stratum was assumed to follow a binomial distribution where the estimated probability was a

linearized function of fixed factors. The logit function linked the linear component and the

assumed binomial distribution. Similarly, the estimated catch observed on positive trips was a

function of similar fixed factors with the log function as a link.
13

A stepwise approach was used to quantify the relative importance of the main factors

explaining the variance in bycatch rates. That is, first the Null model was run, in which no

factors were entered in the model. These results reflect the distribution of the nominal data.

Each potential factor was then tested one at a time. For each run, the deviance was calculated as

the negative of twice the difference between the log-likelihood under the model and the loglikelihood under the maximum achievable (saturated) model:

The results were then ranked from greatest to least reduction in deviance per degree of freedom

when compared to the Null model. The factor which resulted in the greatest reduction in

deviance per degree of freedom was then incorporated into the model, provided two conditions

were met: (1) the effect of the factor was determined to be significant at at least the 5% level

based upon a χ

2

 (Chi-Square) test, and (2) the deviance per degree of freedom was reduced by at

least 1% from the less complex model. This process was repeated, adding factors (including

factor interactions) one at a time at each step, until no factor met the criteria for incorporation

into the final model. The final model then, included any significant fixed and random

(year)*factors interactions.

 The product of the standardized proportion positives and the standardized positive catch

rates was used to calculate overall standardized catch rates. For comparative purposes, each

relative index of abundance was obtained dividing the standardized catch rates by the mean value

in each series.

Results and Discussion

The results of the stepwise procedure to develop the models are shown in Table 3 for the

proportion positive bycatch model and in Table 4 for the positive bycatch model. The factors

examined did not explain much of the catch rate variability in either model. For the proportion

positive bycatch model, only the factor of latitude (LAT) met the conditions required for

inclusion in the model (significance at the 5% level and reducing deviance per degree of freedom

by at least 1%). The factor YEAR was included in the final model since this was the factor of

concern and for which the least-square means were to be calculated. Together, LAT and YEAR

accounted for only a 4.4% reduction in deviance per degree of freedom from the NULL model.

For the positive bycatch model, none of the tested factors met the conditions required for

inclusion in the model. This is not surprising, since there is very little contrast in the positive

catch data; nearly 95% of the positive catch observations were of 1 turtle, with remainder being 2

turtles caught per tow. Again, YEAR was included in the final model in order to calculate the

least square means. Although the positive catch analysis results are unreliable due to the lack of

contrast, the end result is that values close to the nominal positive catch rates are combined with

the results of the proportion positive analysis to produce annual index values. Therefore, the

conclusions are primarily based upon the proportion positive analysis.

The results of the model fits for the updated indices are shown in Table 5 for the

proportion positive bycatch model and in Table 6 for the positive bycatch model. The index

values are shown in Table 7 and in Figure 6. The relative observed bycatch rates are also shown

in Figure 6. It is clear that the standardized trend varies little from the nominal trend. However,

the standardization procedure does provide some measure of the uncertainty around the relative

D y u l u y l u y

*

max ( ; $) = −2( ( $; ) − ( $ ; ))
14

indices calculated from this survey. This permits the calculation of the power of this survey to

detect changes in abundance.

It does appear that the catches have been increasing; a regression analysis indicated an

increasing trend of 11.2%/yr relative to the catch during the first year. However, the error about

each year’s point estimate is large and the number of captures in 2000 is not significantly

different than the number captured in 1990 (p=0.24). Thus, no significant trend was detected in

this fishery-independent survey to indicate that the in-water population of loggerheads in the

Western North Atlantic is increasing.

We assessed the power of the SEAMAP monitoring program to detect a trend in

loggerhead sea turtle abundance by utilizing the program TRENDS. At a recent workshop on inwater sea turtle population trends held in March 2000 (Bjorndal and Bolten 2000) the emphasis

was on minimizing the Tye II error (maximizing power to detect trends) so the Type I error was

set to 0.2 and the Type II error to 0.1. For purpose of comparison to the results of that workshop,

we used the same criteria and ran two trials. Trial A was to determine the minimum detectable

annual rate of change within the 11 years duration of this program, assuming population growth

is exponential and declining, Type I Error (α)=0.2, and Type II Error (β)=0.1, the statistical

power = 0.9. Trial B was to determine the minimum duration (yrs) required to detect an annual

decline of 25%. These analyses indicated that the SEAMAP monitoring program could detect a

trend of –0.24%/year after 11 yrs, the same amount of time required to detect a decline of

25%/year. Therefore, unless the population was changing in size at about 25% per year, it is

unlikely (<90% probability) that the SEAMAP monitoring program would be able to detect a

trend within the duration that it has been ongoing (11 yrs).

Stock Assessment

Crouse et al. (1987) developed the first stage-based matrix population model for the

loggerhead turtle. They collapsed Frazer’s (1983a) 54-stage loggerhead life-table into 7 stages,

hatchlings, small juveniles, large juveniles, subadults, novice breeders, 1st year remigrants and

adults. In a further refinement of the model, Crowder et al. (1994) reduced the 7-stage model to

a 5-stage model, combining all breeding adults into one stage. Crowder et al. (1994) also

presented an age-based matrix model of loggerheads in order to qualitatively assess how

population trajectories respond to management practices.

Heppell et al. (in press) redefined the stages first changing the model from a postbreeding census to a pre-breeding census, incorporating first year survival into the fertility term

and eliminating hatchlings as a separate stage. In addition, Heppell et al. (in press) eliminated

the subadult stage and defined three juvenile stages, pelagic juveniles, small benthic juveniles

and large benthic juveniles. TEWG (1998) defined the cutoff between small and large benthic

juveniles at 70 cm straight carapace length (SCL) based on differential habitat utilization.

Loggerheads slightly larger that 70 cm may be too large to fit through the smallest current TED
15

openings 19, introducing potentially different mortality rates between the two benthic juvenile

stages. Because current regulations require smaller TED openings in the Gulf of Mexico than in

the Atlantic, this cutoff can be a bit fuzzy, but large juveniles and adults probably experience

limited benefits from TEDs. Heppell et al. (in press) used 70 cm SCL as the cutoff between

small and large benthic juveniles. Another change from the previous models is that a variable

remigration interval is incorporated, making nesting females a separate stage from non-nesting

females. As in Crowder et al. (1994), Heppell et al. (in press) expanded the model to be agebased in order to assess population responses to TED regulations. The model, then, is essentially

a Leslie matrix, with annual survival rates on the subdiagonal and fecundity in the top row. The

row of the matrix equivalent to age at reproductive maturity represents breeding females. The

remaining 4 rows of the matrix cycles the surviving neophytes and remigrants based on the

proportion of females returning to nest after 1, 2, 3, 4, or 5 years which are 3%, 56%, 31%, 7%

and 3% (Richardson et al. 1978).

The models we present here are the same as the 5-stage structured models of Heppell et

al. (in press) and are similarly expanded to age-based models. However, to update the

parameters of the models as much as possible we analyzed new data sets to determine the best

available information to use in this current stock assessment. We construct models using both

the historical and updated vital rates.

Vital Rates

Duration of Stages

Heppell et al. (in press) present two models, both incorporating the structure described

above. Model 1 uses stage durations that are consistent with the previous models and derive

from a von Bertalanffy growth curve developed by Frazer (1987). Model 2 uses longer stage

durations that are based on a von Bertalanffy growth curve developed from a preliminary

analysis of a mark-recapture study in North Carolina (Braun-McNeill et al. in press). Since

Frazer’s (1987) growth model was based on loggerheads caught in Florida, we thought that

Model 1 might be representative of a faster growing population in the south, and model 2

representative of a slower growing northern population (see previous section on stock

definition).

To further assess individual growth rates and the possibility of regional variability, we

analyzed published von Bertalanffy growth curves that were based on mark-recapture data from

wild loggerheads in the southeast U.S. (Table 9, Fig. 7). The curves prepared by Braun-McNeill

et al. (in prep)20 used data for turtles whose time between first capture and recapture was greater

than 11 months. Schmid (1995) prepared a curve where he only used recaptures when the time

 

19 Epperly, S.P and W.G. Teas. 1999. Evaluation of TED opening dimensions relative to size of turtles stranding in

the Western North Atlantic. U.S. Department of Commerce, National Marine Fisheries Service SEFSC Contribution

PRD-98/99-08, Miami, Fla, 31 pp.

20 Braun-McNeill, J., S.P Epperly, and L. Avens. A preliminary analysis of growth rates of immature loggerhead

(Caretta caretta) sea turtles from North Carolina, U.S.A. Manuscript in preparation.
16

between first capture and recapture was greater than or equal to 365 days (designated as ** in

Table 8). As with other poikilotherms, metabolic activity in loggerheads is external-temperature

dependent and it is likely that little or no growth occurs during the winter months (Castanet

1994), hence inferring growth rates from time periods of less than one year may result in

inaccuracies. The Schmid (1995)** curve was prepared from only 19 growth rates and it is

unclear what the size distribution was for turtles included in the analysis. The Braun-McNeill et

al. (in prep)20 curve was estimated primarily from small benthic juveniles, using growth rates

from 57 turtles. In order to apply the Braun-McNeill et al. (in prep)20 curve to the entire benthic

life-stage, we extended the size range by adding additional mark-recapture growth rates for

animals greater than 70 cm SCL from the CMTTP21. We used records from both data sets for

animals that were at large for at least 0.9 yr, had a straight carapace length recorded, and did not

indicate negative growth. From the CMTTP, in order not to bias the growth curve to the growth

rates of a few individuals, we used only one growth rate for each animal included, even if there

were multiple recapture records for the animal (Fig. 8 and 9).

Chaloupka and Limpus (1997) and Limpus and Chaloupka (1997) found sex-specific

growth rates in hawksbill (Eretmochelys imbricata) and green (Chelonia mydas) sea turtles in the

southern Great Barrier Reef. The turtles in these studies were sexed by internal observation of

the gonads. As sex cannot be determined externally for juvenile sea turtles and there are little

data on growth of loggerhead turtles of known sex in the Western North Atlantic we could not

attempt to look at sex-specific growth rates.

The new growth curve is derived from animals throughout the southeast U.S. and cannot

be used to address the question of regional variability in growth rates. But the intrinsic rate of

growth (k) for this curve did not deviate much from that calculated by Braun-McNeill et al. (in

prep) and is comparable to those estimated by Schmid (1995) and Foster (1994) (Table 8, Fig. 7).

Hence we feel it is the best overall representation of loggerhead growth rates for the southeast

U.S. available to date and we use it in the current model to estimate stage-durations, time-tomaturity and age-at-size.

The Frazer (1987) curve was prepared from juvenile growth rates of wild loggerheads in

Florida that had overall higher growth rates than those measured in North Carolina (Mendonca

1981, Frazer and Ehrhart 1985, Frazer 1987, Braun-McNeill et al. in prep) and we cannot

discount the possibility that this curve is representative of a maximum growth rate for wild

loggerheads. Because of this and to be consistent with the previous models, we also consider

models based on Frazer’s (1987) growth curve.

Bjorndal et al. (2000) evaluated the duration of the pelagic stage. Their results estimate a

minimum time of 6.5 years and an average time of 8 years for the duration of this stage. As the

model we are using incorporates the first year into the fecundity function, we use 6 years and 7

years as minimum and average durations of the pelagic stage.

 

21 Unpublished Data. The Cooperative Marine Turtle Program was established by NMFS in 1980 to centralize the

tagging programs among sea turtle researchers, distribute tags, manage tagging data, and facilitate the exchange of

tag data.
17

Size-at-Stage

The earlier models define 58.1 cm SCL as the break between small and large juveniles

and 87 cm SCL as the size at maturity (Crouse et al. 1987, Crowder et al. 1994). TEWG (1998)

recommends 92 cm SCL as the average size of neophyte nesters. Heppell et al. (in press) uses

45 cm SCL as size at first settlement from pelagic to benthic habitats and 92 cm SCL as size at

maturity.

In the models used for this stock assessment, we consider two size-at-stage scenarios.

The first looks at a minimum size-to-stage and the second an average size-to-stage. Bjorndal et

al. (2000) suggests 42 cm SCL as the smallest size at first settlement for loggerheads. Bjorndal

et al. (2000) also estimate that the average size at settlement is 53 cm CCL or 49cm SCL (using

their SCL to CCL conversion equation).

For size at maturity, we analyzed the CMTTP21 for original tagging events from nesting

beach survey projects where SCL was recorded. We calculated an average of 90.38 cm SCL

(SD=5.08) with the 5th and 95th percentiles equal to 82.5 and 99.2 cm SCL respectively (Fig 10).

Given that some individuals might nest before they get tagged for the first time or the first tag

might have been lost and the turtle not recognized as having been tagged, we acknowledge that

90.38 cm SCL is perhaps biased large as an average size-to maturity.

Hence, for the minimum size-to-stage scenario we use 42 cm SCL as the cutoff between

pelagic juveniles and small benthic juveniles and 83 cm SCL (from the 5th percentile of the

analysis of the CMTTP)21.as size-to-maturity. For the average size-to-stage scenario we use

Bjorndal et al.’s (2000) estimate of 49 cm SCL as the cutoff between pelagic juveniles and small

benthic juveniles and 90 cm SCL (calculated from the CMTTP21) for average size-to-maturity.

Sex Ratios

The sex of loggerhead sea turtle hatchlings is environmentally determined by a restricted

range of nest incubation temperatures. Pivotal and transitional ranges of temperatures determine

if the nest will produce males, females or both (Mrosovsky and Pieau 1991). Mrosovsky and

Provancha (1989) suggest that the majority of a major rookery near Cape Canaveral, Florida

incubates at such warm temperatures that virtually no males are produced. Presumably because

of a shorter nesting season, characterized by cool beginning and ending temperatures, males are

predominately produced in the Northern subpopulation.

We assessed the sex ratios of benthic loggerhead sea turtles by analyzing the STSSN

database22 for dead-stranded loggerheads for which sex had been ascertained by direct

examination of the gonads. It is likely that adult loggerheads have sex specific dispersal and

consideration of adults in the analyses may bias the results. Therefore, to be conservative we

 

22 The Sea Turtle Stranding and Salvage Network is a cooperative endeavor between NMFS, other federal agencies,

the states, many academic and private entities, and innumerable volunteers. Data are archived at the National Marine

Fisheries Service Southeast Fisheries Science Center in Miami, Fla.
18

only considered loggerheads less than 80 cm SCL in order to eliminate adults from the analysis.

Sex ratios were then assessed by statistical zone and by state (Table 9).

From mtDNA analyses, we know that the feeding aggregations of juvenile loggerheads

are composed of turtles from the different subpopulations. Bass et al. (199923) analyzed genetic

samples taken from stranded animals from 5 states, Texas, Florida, South Carolina, North

Carolina and Virginia (Fig. 1). We combined information regarding the sex ratios of the juvenile

feeding aggregations with the natal origin probabilities to determine the sex ratios specific to the

analyzed subpopulations.

We restricted our analysis to states where sample sizes were sufficiently large (N≅100),

where samples could be definitely assigned to relatively small (<500 km) geographic areas, and

where all samples were analyzed for the same suite of contributing source populations. Data on

Florida was not included because it did not meet the small geographic area criteria defined

above. The sample size from Virginia was too small (N=35). The sample size from North

Carolina also was small (N=60), however in another study, additional North Carolina samples

were analyzed, increasing the sample size to 286 (Bass et al. 200024).

We used the genetics data from Texas (N=121)23, South Carolina (N=95)23 and North

Carolina (N=286)24 in combination with juvenile sex ratios from those states (Table 9) to set up

the following linear equations:

74.21 = 83.36S + 10.33N + 6.30M (TX sex ratio and natal origin probabilities23)

67.44 = 65.66S + 24.55N + 9.77M (SC sex ratio and natal origin probabilities23)

65.25 = 64.04S + 29.78N + 5.82M (NC sex ratio and natal origin probabilities24)

S is the percent female hatchlings produced by the South Florida subpopulation, N is the percent

female produced by northern subpopulation and M is the percent female hatchlings from the

Yucatán subpopulation. The above three equations in three unknowns solved to give the

following percentages:

S = 80% Female

N = 35% Female

M = 69% Female

We can estimate the south Florida subpopulation produces 80% females and the northern

subpopulation produces 65% males. Limited data for the Yucatán subpopulation suggest nearly

70% of hatchlings are female. The sex ratios for the northern and south Florida subpopulations

are consistent with what is known about the temperature-dependent sex determination of

 

23 Bass, A.l. S-M. Chow, and B.W. Bowen. 1999. Final report for project titled: genetic identities of loggerhead

turtles stranded in the Southeast United States. Unpublished report to National Marine Fisheries Service, order

number 40AANF809090. Department of Fisheries and Aquatic Sciences, University of Florida, Gainesville, Fla.,

11pp.

24 Bass, A.L. S.P. Epperly, J. Braun-McNeill and A. Francisco. 2000. Temporal variation in the composition of a

loggerhead turtle (Caretta caretta) developmental habitat. Unpublished manuscript. Department of Fisheries and

Aquatic Sciences, University of Florida, Gainesville, Fla., 26 pp.
19

loggerheads. For lack of specific data to the contrary, previous models have used 0.5 as the

default sex ratio for loggerheads (Crouse et al. 1987, Crowder et al. 1994 and Heppell et al. in

press). We now have regional sex ratios to use in the model but also construct the same models

with a sex ratio of 0.50 for comparison with historical models.

Survival Rates

For the model runs in which stage duration was estimated using Frazer’s (1987) growth

curve, we use the same survival rates that were estimated by Frazer (1983a, 1986) and used in

the previous models (Crouse et al. 1987, Crowder et al. 1994, Heppell et al. in press). Heppell et

al. (in press) found they needed to increase survival rates from the previous models to gain a

realistic life history for the longer stage durations. Hence we wanted to readdress benthic

juvenile and adult survival rates.

Benthic Juveniles

Frazer (1987) estimated juvenile survival rates for loggerhead sea turtles using a catch

curve (Seber 1982). But it seems likely that if a faster growth curve is used to estimate age-atsize, the resulting slope on the catch-curve will be steeper than for age-at-size calculated from

slower growth curves. Steeper slopes correlate with higher instantaneous mortalities.

We analyzed the STSSN22 data using a catch curve analysis. We used only data from

1986-1989 (pre-TED), assuming the population was at a stable age distribution at that time and

that dead stranded animals are a representative cross-section of the body sizes of turtles in the

population. Catch curves are created by plotting ln(Nx) versus x where x is age and Nx is the

number of individuals in the sampled population at age x. The age at which all individuals have

fully recruited to the population (threshold age (Seber 1982)) is estimated as the peak in the

curve. Age-at-size was calculated for each dead stranded loggerhead using the new growth

curve. Nx was calculated for each one-year age class (x) and ln(Nx) was plotted versus x (Fig.

11).

Threshold age was determined at 2 years post-settlement. We calculated the instantaneous

mortality rate (z) from linear regressions on the declining arm of the catch curve in three

different ways (Fig. 12):

• From threshold age to the age corresponding to 70 cm SCL

• From threshold age to the age corresponding to 90 cm SCL

• From threshold age-to-age 20, the point where the trend in the curve start to break-up.

Breaking the catch curve at the 3 different points resulted in similar survival rates, 0.893, 0.929

and 0.908 respectively. To be conservative, we use 0.893 as the pre-TED annual survival rate

for small and large benthic juveniles in the current models.

TEWG (2000, pg. 46) reviews estimates of quantitative decreases in strandings after the

imposition of TED regulations based on analyses of strandings from South Carolina and Georgia
20

(Crowder et al. 1995, Royle and Crowder 199825, Royle 200026). It is unclear how to relate the

percent decreases in strandings (reported at between 37 and 58%) to reductions in instantaneous

mortality (z). Heppell et al. (in press) used a value of 30% reduction in mortality as the amount

by which TED use reduces overall mortality of the affected stages of loggerhead sea turtles.

As the smallest TED openings only allow small turtles to pass through19, we applied a

30% reduction in mortality to small benthic juveniles only to estimate the annual survival rate of

this size class after 1990. We calculated the new annual survival rate for small benthic juveniles

by multiplying z, the instantaneous rate of mortality by 0.7.

Adults

For adult survival probabilities, we analyzed nesting beach tag return data for two nest

monitoring projects using modifications of the Cormack-Jolly-Seber approach (Cormack 1964,

Jolly 1965, Seber 1965, Lebreton et al. 1992). The two nesting beaches analyzed were

Melbourne Beach, Florida27 and Wassaw Island, Georgia28 (Williams and Frick 2001). For

Wassaw Island, tag-loss was accounted for according to Frazer (1983b). The program MARK

(White and Burnham 1999) was used to estimate survival rates for each data set based on the

models of Lebreton et al. (1992). For Wassaw Island, the model incorporating time dependent

survival probability (φt ) and time independent capture probability (p.) gave the best goodness-offit based on Akaike’s Information Criterion. For Melbourne Beach the model giving the best

goodness-of-fit incorporates time dependent survival and capture probabilities (φt, pt). Average

estimated annual survival probabilities were 0.79 for Wassaw Island and 0.83 for Melbourne

Beach. The models used do not account for emigration, hence,

φt = St (1-Et )

where St is the annual survival rate and Et is the emigration rate. We know that nesting

loggerheads do not have strict nest-site fidelity (CMTTP21, LeBuff 1974, Ehrhart 19792, Bjorndal

et al. 1983, LeBuff 1990) but the actual value of Et is unknown so we use φt as an estimate of

annual survival acknowledging that this value is lower than the true survival rate and therefore

conservative. The annual survival rates calculated from the tag-return data (0.79 and 0.83) are in

close agreement with the value of 0.8091 originally estimated from Little Cumberland Island

data (Frazer 1983b). In light of the uncertainty associated with these values, we selected the

mean of all three values, 0.812 as representative of adult annual survival in the current model.

 

25 Royle, J.A. and L.B. Crowder. 1998. Estimation of a TED effect from loggerhead strandings in South Carolina

and Georgia strandings data from 1980-97. Unpublished report, U.S. Fish and Wildlife Service, Laurel, Maryland,

11pp.

26 Royle, J.A. 2000. Estimation of the TED effect in Georgia shrimp strandings data. Unpublished report, U.S. Fish

and Wildlife Service, Laurel, Maryland, 11pp.

27 Ehrhart, L.M. Unpublished data. Department of Biology, University of Central Florida, Orlando, Fla.

28 The Caretta Research Project, Savannah Science Museum, P.O. Box 9841 Savannah Ga. and the U.S. Fish and

Wildlife Service, Savannah Coastal Refuges, 1000 Business Center Drive, Suite 10, Savannah, Ga.
21

Pelagic Juveniles

Due to the cryptic nature of this life stage, no data are available to directly measure

pelagic juvenile survival rates. Because we have estimates for all other inputs into the model, we

can infer pelagic survival rates from those rates and population trends. We assessed the range in

potential annual survival rates of pelagic juveniles by allowing for the uncertainties in other

parameter estimates and running the model using combinations of the inputs as discussed in the

previous sections and three values for λ for the northern subpopulation (λ = 0.95, 0.97 and 1.0)

as discussed above in the Status and Trends section. We feel that the overall population trend for

the northern subpopulation prior to 1990 is encompassed within the range of λ values we used.

Fecundity

Heppell et al. (in press) used reproduction parameters from TEWG (1998) and survival to

year 1 from Frazer (1983). We use the same values for the current models, which are nests per

breeding female = 4.1, eggs per nest = 115, and survival to year 1 = 0.6747. The fecundity value

in the matrix is:

F = 4.1 x 115 x (proportion of female offspring) x 0.6747.

Population Models

We considered four different stage duration scenarios (Models 1-4). These were based

on the two individual growth models, Frazer’s (1987) (Frazer) and the new one presented here

(New). For each growth curve, we estimated stage durations based on the minimum-size-tostage and the average-size-to-stage values discussed in the size-at-stage section and survival rates

were used as discussed previously (Tables 10-13). We used the same fecundity parameters as in

Heppell et al. (in press) with the exception of the sex ratio.

For each model, we ran 3 scenarios, using λ = 0.95, 0.97 and 1.00. As these reflect the

range of estimates for the pre-1990 population growth rates for the northern subpopulation, we

used 0.35 as the proportion of female offspring in these models. For each of these 12 (4 models

times 3 population growth rates) runs of the model, we determined the appropriate annual

survival rate for the pelagic stage (Table 14). In Model 2, the pelagic annual survival probability

for the λ = 1.0 scenario would have to have exceeded 1.0, so we discount this possible

combination of vital rates and consider only the remaining 11 runs of the model.

The right eigenvector of a projection matrix gives the proportional distribution of ages for

a population at a stable age distribution (Caswell 2001). To check how well the age distributions

associated with each model correlates with the natural population, we summed the proportional

contributions across the benthic stages (small, large, and adult) to get the predicted stable stage

structure. We compared this to the observed stage structure based on an analysis of strandings

between 1986 and 1989 (the same data used to create the catch curve) (Fig. 13). Models 3 and 4

appear to have the best fit with the strandings data.

Elasticity of Stages
22

For matrix projection models, an elasticity analysis examines the proportional

contribution of the asymptotic population growth rate (λ) to changes in the vital rates that

compose the elements of the transition matrix (de Kroon et al. 1986, 2000). Elasticities also

reveal the proportional contribution of each element of the matrix to λ. For an age-based matrix,

elasticities can be summed over stages to find the proportional contribution of each major lifestage to λ. The elasticity of λ to juvenile stage is dependant on the duration of those stages

(Caswell 2001, Heppell et al. 2000). Longer stage lengths have higher elasticities. Thus, for

Model 1, small and large benthic juveniles have the same elasticity (Fig. 14). For Model 2, small

benthic juvenile elasticity is lower than that of pelagic juveniles while the elasticity of the large

benthic juveniles is much higher than either of the other juvenile stages. Similarly, the

elasticities of the juvenile stages for Models 3 and 4 correlate with the stage durations (Tables 12

and 13) and the longest stage duration, the large benthic juvenile stage of Model 4, has the

highest elasticity (Fig. 14). These are the elasticities for λ = 0.95, the specific values change

only slightly with changes in λ and the overall trends remain the same.

Sex Ratios

There is no reason to expect different pelagic juvenile stage survival rates for loggerheads

originating from the south Florida subpopulation as compared to the northern subpopulation. For

the benthic stages, there are potential differences in nearshore mortality from anthopogenic

sources. As we have no current means of quantifying such differences, we assume the benthic

stage survival rates are the same for both subpopulations. There is, however, evidence of a

higher proportion of females being produced in the South Florida subpopulation. Hence, we also

ran the same 11 models as described previously, with a proportion of female offspring equal to

0.80. For consistency with the historical models, we also ran the 11 models with a proportion of

female offspring equal to 0.50.

Population Projection

Following Heppell et al. (in press), post-1990 population trajectories were run for each

model (now numbering 33 – 11 times the 3 sex ratios) by initializing with a population at stable

age distribution for the appropriate combination of model and λ, assuming 2000 nesting females

(TEWG 1998). Small benthic juvenile mortality was decreased by 30% and the population

projected based on the new survival rates (Fig. 15-17). Obviously, increasing small benthic

juvenile survival rates has the effect of increasing population growth rates for each model

scenario (see Fig. 18 for new population growth rates). However, when the populations are

initialized at a declining rate of 5% per year (λ=0.95), a 30% decrease in mortality of small

benthic juveniles is not enough to reverse the declining trends regardless of the sex ratio (Fig.

18). At an initial population decline of 3% per year, declining trends are reversed in Models 1

and 2 except at a sex ratio of 0.35 for Model 2. At stable population growth, λ=1.0, a 30%

decrease in small benthic juvenile mortality alone results in increasing population trends in all

model scenarios (Fig. 18). Note that the λ values given in Fig. 15-18 are the initial population

growth rates. The populations in these projections will eventually stabilize to the respective

population growth rates indicated in Fig. 18.
23

TEWG (1998) presented a population model for the Kemp’s ridley sea turtle for which

the model projections were fit to observed nesting trends. This was possible for Kemp’s as there

is only a single stock with one primary nesting aggregation and 30 years of nesting trend and

hatchling production data. Loggerheads of the southeast U.S. have a much more complicated

stock structure with numerous nesting aggregations, only some of which are currently monitored

and very few were regularly monitored prior to 1989.

We are using the four model scenarios, each with three starting λ values to address the

uncertainties in the model parameters. The actual stage duration and population growth rates are

likely bracketed. Due to the uncertainty inherent in these models, we do not assert that the

population projections presented here and elsewhere in this document are quantitative

predictions of future sea turtle numbers. They should be viewed only as qualitative outcomes of

the implementation of management strategies (or lack thereof), indicating the time lags that can

be expected before the effects of management are seen in terms of numbers of nesting females

(Crowder et al. 1994). This is also why we do not put specific years on the x-axis of the

projection plots (Fig. 15-17).

We start the population projections at stable age distribution. At time one we increase

survival of the small benthic juveniles which perturbs the population out of stable age

distribution, giving a pulse of small benthic juveniles. The lag time before the initial pulse of

small benthic juveniles are seen as an increase in the number of nesting females is equal to the

length of the duration of the large benthic juvenile stage. After a length of time equivalent to the

duration of the small benthic juvenile stage, this pulse in the numbers of nesting females levels

out and the populations temporarily stabilize. However, there are now increased numbers of

nesting females producing increased numbers of offspring. Following a period equal to age at

reproductive maturity, when these increased numbers of offspring begin to mature, another pulse

is observed in the number of nesting females. Due to the duration of the stages, the latter pulse is

seen only in Model 1. For this model the duration of the large benthic juvenile stage is 7 years.

The first pulse for Model 1 occurs at 7 years (Fig. 15-17, Model 1). The duration of the small

benthic juvenile stage is 7 years, hence, after 14 years the initial pulse levels out (Fig. 15-17,

Model 1). Age to reproductive maturity for Model 1 is 21 years, therefore, 21 years after the

first pulse began, or at 28 years, the number of nesting females pulses again. The pulses will

continue until the populations again reach stable age distribution, which often takes two

generations or more. Similar dynamics are occurring in the population projections for the other

models, however, the time series were not run long enough to see the effects of increased

numbers of offspring (Fig. 15-17; Models 2-4).

In model 2, the populations are still declining for 35% female offspring and starting λ =

0.95 and 0.97, and for 50 % female offspring and starting λ = 0.95 following the increase in

small benthic juvenile survival (Fig. 18). The populations are slightly increasing following the

increase in small benthic juvenile survival for starting λ = 0.97 (Fig. 18). As described above,

there is a surge in number of nesting females as the increased numbers of small benthic juveniles

pulse through, after which the population continues to decline (Fig. 15-17; Model 2). For

Models 3 and 4, λ = 0.95 and 0.97, similar dynamics are occurring, however, the length of the

large benthic juvenile stage is very long and the populations are still declining by as much as 4%
24

per year (Fig 15-17, Models 3 and 4; Fig. 18), hence the pulse of small benthic juveniles is not as

obvious.

The meta-analysis of nesting trends for the northern subpopulation indicates that numbers

of nesting females in this region may have increased since 1990. In our models, we only allow

for increases in small benthic juvenile survival and thus it takes a period equal to the duration of

the large benthic juvenile stage to begin to see increases in numbers of nesting females (Fig. 15-

17, Tables 10-13). The effects of TED use on decreasing mortality in sea turtles have been

documented quantitatively (TEWG 1998, Crowder et al. 1995, Royle and Crowder 199825, Royle

200026). Using the cut-off of 70 cm SCL and below for the benefits of TED use is also justified

as that is about the maximum size turtle that can fit through the smallest size TED openings

allowed under current regulations (Epperly and Teas 199919).

There are other anthropogenic sources of sea turtle mortality that have been mitigated

over the years. For example, when the loggerhead sea turtle was listed as a threatened species in

1978 under the Endangered Species Act of 1973 (PL93-205), taking eggs and nesting females,

and keeping in-water catches became illegal. South Carolina sturgeon fishers using large mesh

gill nets and operating in the coastal waters of South Carolina and North Carolina, were

implicated in mass-dead-stranding events of loggerheads up to 89 cm SCL from mid-April to

early May of 1977 and 1981 (Crouse 1985, Ulrich 197829). This fishery was closed in 1986 in

South Carolina (NMFS and USFWS 1991) due to declines in sturgeon populations. North

Carolina initially imposed restrictions on the use of large mesh gill nets between February and

September (N.C. Marine Fisheries Regulations, NCAC 15 3B.0402(5)) and as of 1991, the

sturgeon fishery has been closed. The state of Florida now prohibits the use of entangling nets

(Florida Fish and Wildlife Conservation Commission, Division of Marine Fisheries Regulations,

Chapter 68B-4.0081, issued 3-1-92, amended, 7-18-94 and 4-27-98). Takes of pelagic juvenile

loggerheads in US and international longline fisheries in the North Atlantic are only now being

quantified, but estimates from the Eastern North Atlantic are large (Bolten et al. 1994) and could

alter population trends (Crowder et al. 1994).

Combining these factors and possibly others that are not documented may contribute to

the potentially increasing trends in nesting females seen in the meta-analysis results for the

northern subpopulation, but that analysis is presented with caution as it is unweighted and does

not consider the relative abundance of each beach. As factors may have combined to contribute

to possibly increasing nesting population trends for the northern subpopulation, they would be

accounted for in the scenarios that set λ = 1.0. Conversely, there are likely other sources of

mortality offsetting the mitigated ones that are resulting in the slow-down of increasing nesting

trends in the south Florida subpopulation. None of these other mortality sources are well studied

or documented and cannot be considered quantitatively in the population models.

There is some concern about the nest trend data used in the meta-analysis. It is possible

that what appears to be increasing trends is an artifact of increasing survey efforts. Attempts

were made to circumvent this possibility by only using data that appeared to represent consistent

 

29 Ulrich, G.F. 1978. Incidental catch of loggerhead turtles by South Carolina commercial fisheries. Unpublished

report to National Marine Fisheries Service, contract numbers 03-7-042-35151 and 03-7-042-35121. South Carolina

Wildlife and Marine Resources Department, Charleston, S.C. 36pp.
25

effort, however, we also do not want to overestimate population growth rates for loggerheads.

Therefore, we continue to consider all three possible scenarios in the impact assessment. We also

need to consider that nesting trends reflect trends in only a very small portion of the overall

population and that uncertainties not included in the model do not provide assurance that

populations will recover.

For λ=0.97 (the median λ evaluated) the models based on the new individual growth

curve, Models 3 and 4, using sex ratios of 0.35 or 0.50, all suggest declining populations after a

30% reducation in mortality for small benthic juveniles. At a sex ratio of 0.8, the population

growth rates were postive for all models except for Model 4. For the sex ratio representative of

the northern subpopulation, 0.35, a 30% decrease in mortality for small benthic juveniles was not

enough to stabilize the population growth rate unless the initial λ=1.0.

Impacts on the Populations

Recent Stranding Events and Trends

From 1998-2000, strandings decreased in the traditionally high zones 28-32 along the

Atlantic coast (Table 15)12. Strandings in the mid-Atlantic zones 35-37 continued to show an

increasing trend, with loggerhead strandings in zone 35 reaching an unprecedented total of 396

in 2000. More than half of these turtles washed ashore during April and the first week of May

and were likely due to large-mesh gillnet fisheries operating in the area (65 FR 31500-31503,

May 18, 2000).

 Strandings along the southern Florida Gulf coast and in the Florida Keys were

approximately double historic levels in 2000. A persistent red tide during the first five months of

the year30 may have played a role in the increased strandings, especially in zone 3. Loggerhead

strandings in southwest Florida were elevated throughout the shrimping season, possibly as a

result of the turtles being too large to fit through the current TED openings (Epperly and Teas

199931). Beginning in October, many large loggerheads have been found floating with an illness

of undetermined cause in southern Florida and the Keys. These turtles all are extremely weak;

they cannot lift their heads out of water to breathe and most have developed secondary

pneumonia due to aspiration of water into the lungs 32. The mortality rate for turtles found alive

with these symptoms has been greater than 50% and the turtles that are still alive in rehabilitation

facilities are showing few signs of improvement. Researchers believe the turtles may be

suffering from a toxin (Ibid.).

 

30 Mote Marine Laboratory, Sarasota, Fla. 2000. Red Tide Chronology. www.mote.org/~mhenry/rtchrono.phtml

31 Epperly, S.P. and W.G. Teas. 1999. Evaluation of TED opening dimensions relative to size of turtles stranding in

the western North Atlantic. Unpublished Report. NMFS SEFSC Contribution PRD-98/99-08, National Marine

Fisheries Service, SEFSC, Miami, Fla., 31 pp.

32 Richie Moretti, Sea Turtle Hospital, Marathon, FL. Personal Communication (phone) to Sheryan Epperly,

National Marine Fisheries Service, SEFSC, Miami, Fla., January 17, 2001.
26

Fate of Dead Turtles

In FY96 NMFS Office of Protected Resources contracted with Duke University Marine

Laboratory to study the fate of turtles dying at sea to better understand what numbers of stranded

turtles represent. The results will be presented at the upcoming 21st Annual Symposium on Sea

Turtle Biology and Conservation in Philadelphia, Pennsylvania in February (P. Mooreside

personal communication33). Fifteen years of hourly wind speed data, recorded off the North

Carolina coast, were transformed into vectors, converted into wind stress magnitude and

direction values, and averaged by month. Near-shore surface currents were then modeled for the

South Atlantic Bight via a three-dimensional physical oceanographic model (Werner et al. 1999).

Estimated water currents and particle tracks were compared to the spatial locations of sea turtle

carcasses stranded along ocean-facing beaches of North Carolina. On average, the number of

carcasses stranded on ocean-facing beaches may represent, at best, approximately 20% of the

total number of available carcasses at-sea. This evidence, in accordance with the spatial behavior

of modeled lagrangian drogues, indicates that only those turtles killed very close to the shore

may be most likely to strand.

Anthropogenic Impacts

A number of anthropogenic impacts have been identified for loggerhead sea turtles

(National Research Council 1990, NMFS & USFWS 1991) but few outside drowning in bottom

trawls have been quantified with any degree of confidence. While they still cannot be quantified,

new information in recent years has come to light concerning longline fisheries and coastal

gillnet fisheries, and about marine debris and pollution, mortality sources that primarily affect

the pelagic immature stage. A more thorough assessment of anthropogenic mortality sources is

provided in the TEWG reports (1998, 2000). Known sources of impact are listed in Appendix 2.

Pelagic longline fisheries

See Part III.

Trawls

A detailed summary of the U. S. shrimp trawl fishery and the Mid-Atlantic winter trawl

fishery impacts can be found in the TEWG reports (1998, 2000). Other bottom trawl fisheries

that are suspect for the incidental capture of sea turtles are the horseshoe crab fishery in

Delaware (Spotila et al. 199846) and the whelk trawl fishery in South Carolina (Sally Murphy

personal communication34) and Georgia (Mark Dodd personal communication35). In South

Carolina, the whelk trawling season opens in late winter and early spring when offshore bottom

waters are > 55oF. One criterion for closure of this fishery is water temperature: whelk trawling

closes for the season and does not reopen throughout the State 6 days after water temperatures

first reach 64oF in the Fort Johnson boat slip. Based on the South Carolina Department of

Natural Resources Office of Fisheries Management data, approximately 6 days will usually lapse

before water temperatures reach 68oF, the temperature at which sea turtles move into State

waters (David Cupka personal communication36). From 1996-1997, observers onboard whelk

 

33 Pete Mooreside, Duke University Marine Laboratory. Personal Communication (E-Mail of draft extended

abstract) to Sheryan Epperly, National Marine Fisheries Service, SEFSC, Miami, Fla., January 23, 2001.
27

trawlers in Georgia reported a total of 3 Kemp's ridley, 2 green and 2 loggerhead sea turtles

captured in 28 tows for a CPUE of 0.3097 turtles/100ft net hour35. As of December 2000, TEDS

are required in Georgia state waters when trawling for whelk (Ibid.).

A loggerhead was reported captured in a Florida try net (W. Teas personal

communication37). Shrimp trawlers operating in the waters off Venezuela were reported to have

captured a total of 48 sea turtles, of which 15 were loggerheads, from 13, 6000 trawls (Marcano

and Alio 2000). They estimated annual capture of all sea turtle species to be 1370 with an

associated mortality of 260 turtles.

Gill nets

A detailed summary of the gill net fisheries currently operating along the mid- and

southeast U.S. Atlantic coastline that are known to incidentally capture loggerhead can be found

in the TEWG reports (1998, 2000). Although all or most nearshore gill netting in state waters of

South Carolina, Georgia, Florida, Louisiana, and Texas is prohibited by state regulations, gill

netting in other states’ waters and in federal waters does occur. Of particular concern are the

nearshore and inshore gill net fisheries of the mid-Atlantic operating in Rhode Island,

Connecticut, New York, New Jersey, Delaware, Maryland, Virginia, and North Carolina state

waters and/or federal waters offshore thereof. Incidental captures in these gill net fisheries (both

lethal and non-lethal) of loggerhead, leatherback, green and Kemp's ridley sea turtles have been

reported (W. Teas, personal communication37, J. Braun-McNeill personal communication38). In

addition, illegal gill net incidental captures have been reported in South Carolina, Florida,

Louisiana and Texas (W. Teas personal communication37). See Appendix 2 for additional

information.

On October 27, 2000, the North Carolina Division of Marine Fisheries (NCDMF) closed

waters in the southeastern portion of the Pamlico Sound to commercial large-mesh flounder gill

netting as a result of elevated turtle takes by the fishery. From September 15–October 25,

observers documented 17 gill net interactions, eight of which were loggerheads (six released

 

34 Sally Murphy, South Carolina Department of Natural Resources, Charleston, S.C. Personal Communication.

(Phone) to J.Braun-McNeill, National Marine Fisheries Service, SEFSC, Beaufort, N.C., November 27, 2000.

35 Mark Dodd, Georgia Department of Natural Resources, Brunswick, Ga. Personal Communication (Fax) to Joanne

Braun-McNeill, National Marine Fisheries Service, SEFSC, Beaufort, N.C., December 8, 2000.

36 David Cupka, South Carolina Department of Natural Resources, Marine Resources Division, Charleston, S.C.

Personal Communication (E-Mail of the Management Plan for South Carolina’s Offshore Whelk Trawling Fishery -

updated January 1999) to Joanne Braun-McNeill, National Marine Fisheries Service, SEFSC, Beaufort, N.C.,

December 18, 2000.

37 Wendy Teas, National Marine Fisheries Service, SEFSC, Miami, Fla. Unpublished STSSN strandings data.

Personal Communication (E-Mail of strandings data) to Joanne Braun-McNeill, National Marine Fisheries Service,

SEFSC, Beaufort, N.C., December 12, 2000.

38 Unpublished Data. Joanne Braun-McNeill, National Marine Fisheries Service, SEFSC, Beaufort, N.C. Personal

Communcation, December 21, 2000.
28

alive and two dead or injured39). There also were 15 strandings documented from nearby areas

during the same time period.40 The NCDMF and NMFS had just agreed on details of a Section

10 Permit to the Endangered Species Act for the flounder fishery just prior to the closure 41. The

permit established allowable levels of live and lethal gill net interactions for each turtle species,

with a goal of reducing strandings by at least 50 percent from 1999 levels. The fishery was

closed when the incidental take level was met for green sea turtles42. The NCDMF estimated that

there were 50 loggerheads captured at the time of closure and that 44 of those had been

drowned39.

From 1981-1990, 397 loggerhead sea turtles were incidentally captured in gill nets set by

Italian fishermen in the central Mediterranean Sea; gill net mortality was reported to be 73.6%

(Argano et al. 1992). An additional study in this same area estimated 16,000 loggerheads/year

are captured by net with 30% mortality (De Metrio and Megalfonou 1988). Observers of the

Spanish driftnet fishery in the western Mediterranean documented the incidental capture of 30

loggerheads from 1993-1994, of which one was dead; an estimated 236 loggerheads were caught

in 1994 (Silvani et al. 1999). In Nicaragua, although green and hawksbill turtles are targeted,

loggerhead and leatherback turtles are incidentally caught by gill net (Lagueux 1998, Lagueux et

al. 1998, Lima et al. 1999); an estimated 600 loggerheads are caught each year (Lagueux 1998).

Gill nets set for finfish and sharks in Belize are also suspected of catching sea turtles (Smith et

al. 1992). Of the 500-800 turtles sold annually in Belize, 30% are reported to be loggerheads

(Ibid.).

Hook and line

Loggerheads are known to bite a baited hook, frequently ingesting the hook. Hooked

turtles have been reported by the public fishing from boats, piers, beach, banks, and jetties

(Cannon et al. 1994, J. Braun-McNeill personal communication38, A. Cannon personal

communication43, Spotila et al. 199844, STSSN unpublished data12) and from commercial

fishermen fishing for reef fish and for sharks with both single rigs and bottom longlines (S.

 

39 Excel spreadsheet as attachment to E-Mail from Jeff Gearhart, N.C. Division of Marine Fisheries, Morehead City,

N.C. to David Bernhard, National Marine Fisheries Service, SERO, St. Petersburg, Fla., October 25, 2000.

40 North Carolina Division of Marine Fisheries news release, NR-61-2000, “Commercial Flounder Season Closes to

Protect Sea Turtles”, Morehead City, N.C., October 25, 2000.

41 National Marine Fisheries Service. Endangered Species Act Section 10 Permit #1259 issued to State of North

Carolina, Department of Environmental and Natural Resources, Division of Marine Fisheries, Morehead City, N.C.,

October 5, 2000.

42 North Carolina Division of Marine Fisheries news release, NR-61-2000, “Commercial Flounder Season Closes to

Protect Sea Turtles”, Morehead City, N.C., October 25, 2000.

43 Andrea Cannon, National Marine Fisheries Service, SEFSC, Galveston, Texas. Personal Communication to

Sheryan Epperly, National Marine Fisheries Service, SEFSC, Miami, Fla.

44 Spotila, J.R., P.T. Plotkin, and J.A. Keinath. 1998. In water population survey of sea turtles of Delaware Bay.

Unpublished Report. Final Report to NMFS, Office of Protected Resources for Work Conducted Under Contract

#43AANF600211 and NMFS Permit No. 1007 by Drexel University, Philadelphia, Penn., 21 pp.
29

Epperly personal communication45). A detailed summary of the impact of hook and line

incidental captures to loggerhead sea turtles can be found in the TEWG reports (1998, 2000).

Power plants

Power plants are known to entrain loggerhead sea turtles at the intake canals to their

cooling systems. A detailed summary of the incidental capture of loggerhead sea turtles in power

plant intake screens can be found in the TEWG reports (1998, 2000).

Pound Nets

Pound nets are a passive, stationary gear that are known to incidentally capture

loggerhead sea turtles in Massachusetts (R. Prescott personal communication46), Rhode Island,

New Jersey, Maryland (W. Teas personal communication37), New York (Morreale and Standora

1998), Virginia (Bellmund et al., 1987) and North Carolina (Epperly et al. 2000). Although

pound nets are not a significant source of mortality for loggerheads in New York (Morreale and

Standora 1998) and North Carolina (Epperly et al. 2000), they have been implicated in the deaths

of loggerheads in the Chesapeake Bay from mid-May through early June (Bellmund et al. 1987).

The turtles were reported entangled in the large mesh (>8 inches) pound net leads.

Other Fisheries

Incidental captures of loggerheads in fish traps set in Massachusetts, Rhode Island, New

York, and Florida have been reported (W. Teas personal communication37). Although no

incidental captures have been documented from fish traps set in North Carolina 47 and Delaware

(Anonymous 199548), they are another potential anthropogenic impact to loggerheads and other

sea turtles. Lobster pot fisheries are prosecuted in Massachusetts (Prescott 1988), Rhode Island

(Anonymous 199548), Connecticut (Ibid.) and New York (S. Sadove personal communication49).

Although they are more likely to entangle leatherback sea turtles, lobster pots set in New York

are also known to entangle loggerhead sea turtles (Ibid.). No incidental capture data exist for the

other states. Long haul seines and channel nets in North Carolina are known to incidentally

capture loggerhead and other sea turtles in the sounds and other inshore waters (J. BraunMcNeill personal communication38). No lethal takes have been reported. Whelk pots set in

 

45 Sheryan Epperly, National Marine Fisheries Serivce, SEFSC, Beaufort, N.C. Personal Communication

(discussions with commercial reef-fish and shark fishermen in North Carolina), 1984-1998.

46 Robert Prescott, Massachusetts Audubon Society's Wellfleet Bay Wildlife Sanctuary, South Wellfleet, Mass. (EMail) to Joanne Braun-McNeill, National Marine Fisheries Service, SEFSC, Beaufort, N.C., December 1, 2000.

47 Epperly, S.P. and V.G. Thayer. 1995. Marine mammal and sea turtle/fisheries interactions in North Carolina.

Unpublished manuscript. National Marine Fisheries Service, SEFSC, Beaufort, N.C.

48 Anonymous. 1995. State and federal fishery interactions with sea turtles in the mid-Atlantic area, p. 1-12. In

Proceedings of the Workshop of the Management and Science Committee of the Atlantic States Marine Fisheries

Commission July 17-18, Richmond, Virginia. Unpublished report of the ASMFC, Washington, D.C.

49 Sam Sadove, Long Island University, Southampton College, Southampton, N.Y. Personal Communication

(Phone) to Joanne Braun-McNeill, National Marine Fisheries Service, SEFSC, Beaufort, N.C., December 6, 2000.
30

Virginia and North Carolina could potentially entrap loggerheads as they attempt to get to the

bait or the whelks within the trap (Mansfield and Musick 200050).

Bottom set lines in the coastal waters of Madeira, Portugal are reported to take an

estimated 500 pelagic immature loggerheads each year (Dellinger and Encarnacao 2000). Adult

female loggerheads are taken by hand by the indigenous people inhabiting Boavista Island, Cape

Verde, Western Africa (Cabrera et al. 2000). In Cuba, loggerhead, along with green and

hawksbill sea turtles, are commercially harvested (Gavilan 2000, Alvarez 2000).

Marine Debris

An additional source of mortality that has not been adequately assessed is the ingestion of

anthropogenic debris by pelagic turtles. A summary of marine debris impacts can be found in

the TEWG reports (1998, 2000).

Discussion

The recovery plan for this species (NMFS and USFWS 1991) states that southeastern

U.S. loggerheads can be considered for delisting if, over a period of 25 years, adult female

populations in Florida are increasing and there is a return to pre-listing annual nest numbers

totaling 12,800 for North Carolina, South Carolina and Georgia combined (equates to

approximately 3,100 nesting females per year at 4.1 nests per female per season). Nesting trends

indicate the numbers of nesting females associated with the south Florida subpopulation are

increasing. Likewise, nesting trend analyses indicate potentially increasing nest numbers in the

northern subpopulation TEWG 2000, Appendix 1). Given the uncertainties in survival rates

discussed previously and the stochastic nature of populations, the population trajectories should

not be used now to quantitatively assess when the northern population may achieve 3,100 nesting

females.

Similar to results found in previous models, in all model scenarios presented herein, the

juvenile stages have the highest elasticity and maintaining or decreasing current sources of

mortality in those stages will have the greatest impact on maintaining or increasing current

population growth rates. Again, these values are in direct proportion to the stage lengths

determined from the individual growth models used, particularly for the model pairs that use the

same survival rates (Models 1 and 2 and Models 3 and 4) (Heppell et al. 2000). We feel we have

bracketed age-to-maturity with these model pairs, and, for the models using average age-tomaturity (Models 2 and 4), the elasticity of the large benthic juveniles are much higher than

small benthic juveniles while the difference is not as pronounced in the minimum age-tomaturity models (Models 1 and 3). If the new individual growth model presented here accurately

describes loggerhead growth rates and average size-to-maturity is around 90 cm SCL, large

benthic juveniles greater than 70 cm SCL are a critical stage. This stage may not be fully

 

50 Mansfield, K.L. and J. A. Musick. 2000. Characterization of the Chesapeake Bay pound net and whelk pot

fisheries and their potential interactions with marine sea turtle species. Unpublished Report. Virginia Institute of

Marine Sciences Interim Report to the National Marine Fisheries Service, Northeast Regional Office, Gloucester,

Mass., 12 pp.
31

protected under current TED regulations. More information regarding growth rates, habitat

utilization and related mortality sources specific to this stage is important.

As with the previous loggerhead models, the models presented herein assess females only

and make the assumption that there are plenty of males in the population for maximum

fecundity. The actual operational sex ratio necessary on the breeding grounds for maximum

fecundity is unknown. In a genetic analysis of loggerhead clutch paternity, Moore (2000) found

that eggs contained in 31% of the sampled nests reflected contributions from multiple fathers and

10% of the nests had 3 or more fathers. This degree of multiple paternity was detected by only

sampling 10 eggs (<10%) per nest. She expressed concern that males may be a limiting factor

at her study site as a previous study indicated >90% female hatchling production based on

incubation temperatures (Mrosovsky and Provancha 1989).

New results from nuclear DNA analyses indicate that males do not show the same degree

of site fidelity, as do females.9 It is possible, then, that the high proportion of males produced in

the northern subpopulation are an important source of males throughout the southeast U.S,

lending even more significance to the critical nature of this small subpopulation. Our current

understanding of the loggerhead mating system is rudimentary, but further declines or loss of the

northern nesting population (which produces a disproportionate share of males for the whole

population) could contribute to a serious population decline over the entire region.

We have very little sex specific information on the vital rates of sea turtles. If males

mature significantly faster than females and/or if males reproduce every year while females an

average of every 2.5 years (Richardson and Richardson 1982), then the functional sex ratio will

be very different from the actual sex ratio based on hatchling output. This would serve to

alleviate the extreme female bias in hatchling production in Florida. Much more information is

needed about the mating system of loggerheads and sex-specific vital rates in order to truly

assess the impacts of the low production of males in the south Florida subpopulation.

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Table 1. Annual loggerhead turtle (Caretta caretta) nesting and hatching statistics, Dry Tortugas National Park, 1995-2000.

Reproduced from Reardon (200014).

Data Category 1995 1996 1997 1998 1999 2000

Total Nests 269 190 210 190 242 202

Nests Inventoried (n) 169 167 187 142 207 177

98 eggs 100 eggs 105 eggs 102 eggs 103 eggs 99 eggs

Average Clutch Size (50-188) (32-169) (48-169) (60-149) (30-162) (42-148)

82.00% 78.80% 72.30% 76.30% 78.50% 74.90%

Average Hatching Success

* (Not available) (15.3-100.0%) (0.0-100%) (0.0-98.3%) (0.0-99%) (0.0-100.0%)

54.0 days 52.6 days 52.8 days 51.0 days 54.6 days 52.4 days

Average Incubation (45-58; n=94) (46-66; n=148) (45-68; n=158) (44-62; n=133) (48-68; n=184) (45-68; n=152)

* Hatching Success = (hatched eggs/total number of eggs) x 100
40

Table 2. Observed loggerhead turtle bycatch rates in the SEAMAP analysis data set.

YEAR LOGGERHEADS

LOGGERHEADS

PER TOW

LOGGERHEADS

PER STANDARD

UNIT OF EFFORT*

1990 8 0.0261 0.0894

1991 8 0.0258 0.0894

1992 9 0.0288 0.1006

1993 6 0.0192 0.0671

1994 12 0.0387 0.1342

1995 5 0.0160 0.0559

1996 9 0.0288 0.1006

1997 14 0.0449 0.1565

1998 19 0.0609 0.2124

1999 11 0.0353 0.1230

2000 19 0.0609 0.2124

* The standard unit of effort is a one hour tow with a 100 foot headrope.
41

Table 3. Results of the stepwise procedure to develop the proportion positive bycatch rate model for the SEAMAP

analysis data set.

FACTOR df deviance Deviance/df %diff. delta% L ChiSquare Pr>Chi

NULL 3421 999.7656 0.2922 -499.88. .

LAT 3420 969.0417 0.2833 3.046 3.046 -484.52 30.7239 0

YEAR 3411 982.8878 0.2882 1.369 -491.44 16.8778 0.07711

PRECIP 3420 990.6407 0.2897 0.856 -495.32 9.1249 0.00252

SURFACE_SALINITY 3416 991.6322 0.2903 0.650 -495.82 1.1198 0.28997

SURFACE_TEMP 3416 992.4236 0.2905 0.582 -496.21 0.3283 0.56665

NORTWIND 3366 978.7567 0.2908 0.479 -489.38 3.8778 0.04893

BOTTOM_SALINITY 3406 991.6663 0.2912 0.342 -495.83 0.4123 0.52082

BOTTOM_TEMP 3406 991.9716 0.2912 0.342 -495.99 0.1069 0.74366

WESTWIND 3366 982.3208 0.2918 0.137 -491.16 0.3136 0.57546

SEASON 3420 999.4015 0.2922 0.000 -499.7 0.3641 0.54624

START_TIME 3420 999.4426 0.2922 0.000 -499.72 0.323 0.56982

START_DEPTH 3420 999.4965 0.2923 -0.034 -499.75 0.2691 0.60393

BAROMETRIC 3420 999.7322 0.2923 -0.034 -499.87 0.0334 0.85489

AIR_TEMP 3418 999.4576 0.2924 -0.068 -499.73 0.1724 0.67795

LAT+

YEAR 3410 951.9734 0.2792 4.449 1.403 -475.99 17.0683 0.07287

PRECIP 3419 960.4634 0.2809 3.867 -480.23 8.5783 0.0034

SURFACE_TEMP 3415 961.4029 0.2815 3.662 -480.7 1.4663 0.22594

SURFACE_SALINITY 3415 962.3245 0.2818 3.559 -481.16 0.5447 0.46049

BOTTOM_TEMP 3405 961.5905 0.2824 3.354 -480.8 0.878 0.34875

BOTTOM_SALINITY 3405 962.1786 0.2826 3.285 -481.09 0.2899 0.59031

NORTWIND 3365 951.4821 0.2828 3.217 -475.74 1.868 0.17171

AIR_TEMP 3417 967.0103 0.283 3.149 -483.51 1.8022 0.17945

START_DEPTH 3419 967.7791 0.2831 3.114 -483.89 1.2627 0.26115

WESTWIND 3365 953.2602 0.2833 3.046 -476.63 0.0899 0.76437

SEASON 3419 968.6614 0.2833 3.046 -484.33 0.3803 0.53742

START_TIME 3419 968.94 0.2834 3.012 -484.47 0.1017 0.7498

BAROMETRIC 3419 969.0391 0.2834 3.012 -484.52 0.0026 0.95909

LAT+YEAR+

PRECIP 3409 942.3413 0.2764 5.407 0.958 -471.17 9.6321 0.00191

SURFACE_TEMP 3405 944.5417 0.2774 5.065 -472.27 2.1093 0.1464

SURFACE_SALINITY 3405 946.3728 0.2779 4.894 -473.19 0.2782 0.5979

BOTTOM_TEMP 3395 944.9606 0.2783 4.757 -472.48 1.3408 0.24689

NORTWIND 3355 934.1122 0.2784 4.723 -467.06 2.1519 0.14239

START_DEPTH 3409 949.6511 0.2786 4.654 -474.83 2.3223 0.12753

BOTTOM_SALINITY 3395 946.081 0.2787 4.620 -473.04 0.2204 0.63877

AIR_TEMP 3407 949.7093 0.2788 4.586 -474.85 2.0874 0.14852

WESTWIND 3355 935.9986 0.279 4.517 -468 0.2655 0.60635

BAROMETRIC 3409 951.2455 0.279 4.517 -475.62 0.7279 0.39358

SEASON 3409 951.5995 0.2791 4.483 -475.8 0.3739 0.54088

START_TIME 3409 951.7685 0.2792 4.449 -475.88 0.2049 0.65082

LAT+YEAR+

LAT*YEAR 3400 934.7971 0.2749 5.921 0.513 -467.4 17.1763 0.07055

% diff: percent difference in deviance/df between each factor and the null model; delta%: percent difference in

deviance/df between the newly included factor and the previous factor entered into the model; L: log likelihood;

ChiSquare: Pearson Chi-square statistic; Pr>Chi: significance level of the Chi-square statistic.

FINAL MODEL: LAT + YEAR
42

Table 4. Results of the stepwise procedure to develop the positive bycatch rate model for the

SEAMAP analysis dataset.

FACTOR df deviance Deviance/df %diff. delta% L ChiSquare Pr>Chi

NULL 113 4.3251 0.0383 -113.8448. .

START_TIME 112 4.2286 0.0378 1.305 1.305 -113.7965 0.0966 0.75599

LAT 112 4.2334 0.0378 1.305 -113.7989 0.0918 0.76195

AIR_TEMP 112 4.2985 0.0384 -0.261 -113.8315 0.0266 0.87034

START_DEPTH 112 4.3002 0.0384 -0.261 -113.8323 0.0249 0.87455

SEASON 112 4.3014 0.0384 -0.261 -113.8329 0.0237 0.87761

BAROMETRIC 112 4.3197 0.0386 -0.783 -113.8421 0.0054 0.9413

NORTWIND 110 4.2522 0.0387 -1.044 -111.8084 0.0675 0.79508

SURFACE_TEMP 111 4.2948 0.0387 -1.044 -112.8296 0.0277 0.8679

BOTTOM_TEMP 111 4.3037 0.0388 -1.305 -112.8341 0.0187 0.89117

BOTTOM_SALINITY 111 4.321 0.0389 -1.567 -112.8428 0.0014 0.97014

SURFACE_SALINITY 111 4.3224 0.0389 -1.567 -112.8434 0.0001 0.99237

WESTWIND 110 4.3144 0.0392 -2.350 -111.8394 0.0053 0.94192

YEAR 103 4.071 0.0395 -3.133 -113.7177 0.2541 1

% diff: percent difference in deviance/df between each factor and the null model; delta%: percent difference in

deviance/df between the newly included factor and the previous factor entered into the model; L: log likelihood;

ChiSquare: Pearson Chi-square statistic; Pr>Chi: significance level of the Chi-square statistic.

FINAL MODEL: YEAR

NOTE: No factors were found to be significant. Year was included in the final model as this is the factor of interest

for which least-square means are calculated.
43

Table 5. Results of the loggerhead turtle bycatch analysis (1990-2000) in SEAMAP analysis

dataset.

Lo method with binomial error assumption for proportion positives.

 Class Level Information

 Class Levels Values

 year 11 1990 1991 1992 1993 1994 1995

 1996 1997 1998 1999 2000

 Model Fitting Information for _Z

 Weighted by _W

 Description Value

 Res Log Likelihood -11114.2

 Akaike's Information Criterion -11115.2

 Schwarz's Bayesian Criterion -11118.3

 -2 Res Log Likelihood 22228.5

 Solution for Fixed Effects

 Effect YEAR Estimate Std Error DF t Pr > |t| Alpha

 Intercept 7.1539 1.7880 3410 4.00 <.0001 0.05 3.6482 10.6596

 lat -0.3099 0.05585 3410 -5.55 <.0001 0.05 -0.4194 -0.2004

 year 1990 -0.8199 0.4408 3410 -1.86 0.0630 0.05 -1.6842 0.04450

 year 1991 -0.8537 0.4409 3410 -1.94 0.0529 0.05 -1.7181 0.01070

 year 1992 -0.8571 0.4408 3410 -1.94 0.0520 0.05 -1.7214 0.007256

 year 1993 -1.1535 0.4869 3410 -2.37 0.0179 0.05 -2.1082 -0.1988

 year 1994 -0.5189 0.3993 3410 -1.30 0.1938 0.05 -1.3017 0.2639

 year 1995 -1.3396 0.5209 3410 -2.57 0.0102 0.05 -2.3609 -0.3184

 year 1996 -0.7338 0.4244 3410 -1.73 0.0839 0.05 -1.5658 0.09829

 year 1997 -0.3485 0.3808 3410 -0.92 0.3602 0.05 -1.0952 0.3982

 year 1998 -0.06168 0.3556 3410 -0.17 0.8623 0.05 -0.7590 0.6356

 year 1999 -0.5236 0.3992 3410 -1.31 0.1898 0.05 -1.3063 0.2592

 year 2000 0 . . . . . . .

 Type 3 Tests of Fixed Effects

 Num Den

 Effect DF DF Chi-Square F Value Pr > ChiSq Pr > F

 lat 1 3410 30.79 30.79 <.0001 <.0001

 year 10 3410 16.22 1.62 0.0936 0.0942

 Least Squares Means

Effect year Margins Estimate Error DF t Value Pr > |t| Alpha Lower Upper

year 1990 WORK._DS -3.7294 0.3669 3410 -10.17 <.0001 0.05 -4.4487 -3.0101

year 1991 WORK._DS -3.7633 0.3675 3410 -10.24 <.0001 0.05 -4.4838 -3.0428

year 1992 WORK._DS -3.7667 0.3674 3410 -10.25 <.0001 0.05 -4.4870 -3.0463

year 1993 WORK._DS -4.0631 0.4217 3410 -9.64 <.0001 0.05 -4.8898 -3.2363

year 1994 WORK._DS -3.4285 0.3161 3410 -10.84 <.0001 0.05 -4.0483 -2.8086

year 1995 WORK._DS -4.2492 0.4605 3410 -9.23 <.0001 0.05 -5.1520 -3.3463

year 1996 WORK._DS -3.6433 0.3474 3410 -10.49 <.0001 0.05 -4.3245 -2.9622

year 1997 WORK._DS -3.2581 0.2924 3410 -11.14 <.0001 0.05 -3.8313 -2.6848

year 1998 WORK._DS -2.9713 0.2584 3410 -11.50 <.0001 0.05 -3.4779 -2.4647

year 1999 WORK._DS -3.4331 0.3161 3410 -10.86 <.0001 0.05 -4.0529 -2.8134

year 2000 WORK._DS -2.9096 0.2518 3410 -11.55 <.0001 0.05 -3.4033 -2.4158
44

Table 6. Results of the loggerhead turtle bycatch analysis (1990-2000) in SEAMAP analysis

data set.

Lo method with binomial error assumption for positive bycatch tows.

 Class Level Information

 Class Levels Values

 year 11 1990 1991 1992 1993 1994 1995

 1996 1997 1998 1999 2000

 Model Fitting Information for _Z

 Weighted by _W

 Description Value

 Res Log Likelihood 0.4

 Akaike's Information Criterion -0.6

 Schwarz's Bayesian Criterion -1.9

 -2 Res Log Likelihood -0.9

 Standard

 Effect year Estimate Error DF t Value Pr > |t| Alpha Lower Upper

 Intercept 0.05407 0.05025 103 1.08 0.2845 0.05 -0.04560 0.1537

 year 1990 -0.05407 0.09232 103 -0.59 0.5594 0.05 -0.2372 0.1290

 year 1991 -0.05407 0.09232 103 -0.59 0.5594 0.05 -0.2372 0.1290

 year 1992 0.06372 0.08864 103 0.72 0.4739 0.05 -0.1121 0.2395

 year 1993 -0.05407 0.1026 103 -0.53 0.5993 0.05 -0.2575 0.1494

 year 1994 0.03294 0.08077 103 0.41 0.6842 0.05 -0.1272 0.1931

 year 1995 -0.05407 0.1101 103 -0.49 0.6244 0.05 -0.2724 0.1643

 year 1996 -0.05407 0.08864 103 -0.61 0.5432 0.05 -0.2299 0.1217

 year 1997 0.02004 0.07715 103 0.26 0.7956 0.05 -0.1330 0.1731

 year 1998 0.05716 0.07107 103 0.80 0.4231 0.05 -0.08379 0.1981

 year 1999 -0.05407 0.08299 103 -0.65 0.5162 0.05 -0.2187 0.1105

 year 2000 0 . . . . . . .

 Type 3 Tests of Fixed Effects

 Num Den

 Effect DF DF Chi-Square F Value Pr > ChiSq Pr > F

 year 10 103 5.30 0.53 0.8703 0.8654

 Least Squares Means

 Standard

Effect year Margins Estimate Error DF t Value Pr > |t| Alpha Lower Upper

year 1990 WORK._DS 1.39E-17 0.07744 103 0.00 1.0000 0.05 -0.1536 0.1536

year 1991 WORK._DS 1.39E-17 0.07744 103 0.00 1.0000 0.05 -0.1536 0.1536

year 1992 WORK._DS 0.1178 0.07301 103 1.61 0.1098 0.05 -0.02702 0.2626

year 1993 WORK._DS 3.47E-17 0.08942 103 0.00 1.0000 0.05 -0.1774 0.1774

year 1994 WORK._DS 0.08701 0.06323 103 1.38 0.1718 0.05 -0.03840 0.2124

year 1995 WORK._DS 1.39E-17 0.09796 103 0.00 1.0000 0.05 -0.1943 0.1943

year 1996 WORK._DS 1.39E-17 0.07301 103 0.00 1.0000 0.05 -0.1448 0.1448

year 1997 WORK._DS 0.07411 0.05854 103 1.27 0.2084 0.05 -0.04200 0.1902

year 1998 WORK._DS 0.1112 0.05025 103 2.21 0.0291 0.05 0.01156 0.2109

year 1999 WORK._DS 2.78E-17 0.06604 103 0.00 1.0000 0.05 -0.1310 0.1310

year 2000 WORK._DS 0.05407 0.05025 103 1.08 0.2845 0.05 -0.04560 0.1537
45

Table 7. Loggerhead turtle relative abundance indices in SEAMAP analysis

data set.

YEAR value c.v

1990 0.753 0.734

1991 0.728 0.744

1992 0.817 0.697

1993 0.543 0.963

1994 1.101 0.539

1995 0.452 1.137

1996 0.819 0.671

1997 1.281 0.473

1998 1.75 0.375

1999 1.004 0.565
46

Table 8. Published von Bertalanffy growth curves based on mark-recapture studies of

loggerhead sea turtles from the Southeast U.S.

*Compiled from all data in study

**Compiled from occasions where the interval between capture and recapture was greater than 1 year.

 

51Braun-McNeill, J., S.P Epperly, L. Avens, and S. Sadove. A preliminary analysis of growth rates of juvenile

loggerhead (Caretta caretta) sea turtles from North Carolina, U.S.A. Manuscript in preparation.

Source Parameters N Study Region Size Range of Turtles in Study (Initial

Capture)

Time Interval Between

Captures

Braun-McNeill (in

prep

51)

a=106.9

k=0.0521

57 NC 45.1-75.8 cm SCL 0.936-3.523 yrs.

Foster (1994) a=96.74

k=0.0637

54 Southeast

US

62.2-104.2 cm SCL 1-2186 days

Frazer (1987) a=94.7

k=0.115 41 FL

N=8: 53.3-77.3 cm SCL

N=20: Adults, lengths not specified.

N=13: Not specified.

N=8: 0.25-1.64 yrs.

N=20: 1.0-4.1 yrs

N=13: Not specified.

Henwood (1987) a=110.0

k=0.0313

118 FL, GA, SC 45-110 cm SCL, t-t total for study

(N=3679). Not specified for N=118.

> 90 days

Schmid (1995)* a=96.08

k=0.0586

51 FL 38.2-110 cm SCL Less than 90 days to

greater than 365 days.

Schmid (1995)** a=96.10

k=0.0573

19 FL 38.2-110 cm SCL total for study

(N=49), but not specified for N=19.

>365 days
47

Zone Female Males % Female

1 1 0

2 0 0

3 1 0

4 0 0

5 2 0

6 0 0

7 0 0

8 2 2

9 1 0

10 0 0

11 0 0

12 1 0

13 0 0

14 0 0

15 0 0

16 0 0

17 0 0

18 21 10

19 8 2

20 97 30

21 15 7

22 0 0

23 0 0

Gulf: 149 51 0.745

24 1 1

25 7 4

26 2 3

27 11 1

28 10 4

SE FL: 31 13 0.705

29 12 6

30 102 59

31 39 24

32 20 10

33 9 4

34 28 18

35 28 13

36 12 6

37 12 6

38 5 2

39 2 3

40 16 8

41 62 8

42 0 0

43 0 0

44 0 0

NEFL-ME: 347 167 0.675

Total: 527 231 0.695

State (zones) % Female

TX (18-21) 0.742105

FL (1-10, 24-30) 0.655172

GA (30, 31) 0.629464

SC (32, 33) 0.674419

NC (33-36) 0.652542

VA (36-38) 0.674419

Table 9. Juvenile loggerheads (<86 cm CCL)

that dead stranded between 1995 and 1999

and for which sex was determined via direct

examination of the gonads. A. Total counts

of each sex by zone with sex ratios by region.

B. Sex ratios by state.

A.
48

Table 10. Model 1, Frazer – Minimum Size-To-Stage

Stage Duration Annual Survival Rate

Pelagic Juvenile 6 Varies

Small Benthic Juvenile 7 0.6758

Large Benthic Juvenile 7 0.7425

Breeding Adult Indefinite 0.809

Non-breeding Adult Indefinite 0.809

Table 11. Model 2, Frazer – Average Size-To-Stage

Stage Duration Annual Survival Rate

Pelagic Juvenile 7 Varies

Small Benthic Juvenile 6 0.6758

Large Benthic Juvenile 14 0.7425

Breeding Adult Indefinite 0.809

Non-breeding Adult Indefinite 0.809

Table 13. Model 4, New – Average Size-To-Stage

Stage Duration Annual Survival Rate

Pelagic Juvenile 7 Varies

Small Benthic Juvenile 11 0.893

Large Benthic Juvenile 21 0.893

Breeding Adult Indefinite 0.812

Non-breeding Adult Indefinite 0.812

Table 12. Model 3, New – Minimum Size-To-Stage

Stage Duration Annual Survival Rate

Pelagic Juvenile 6 Varies

Small Benthic Juvenile 13 0.893

Large Benthic Juvenile 11 0.893

Breeding Adult Indefinite 0.812

Non-breeding Adult Indefinite 0.812

B.
49

Table 14. Annual pelagic stage survival rates estimated from the 4 model scenarios at 3 values

of λ.

Annual Survival Rate for Pelagic Juveniles

l Model 1 Model 2 Model 3 Model 4

0.95

0.97

1.0

0.744

0.803

0.894

0.910

0.990

>1.000

0.510

0.565

0.660

0.585

0.657

0.780
50

Table 15. Loggerhead turtle strandings by zone, 1998 – 2000.12 Data for 2000 are preliminary.

Cold-stunned turtles, captive-reared turtles and post-hatchlings are not included.

Zone 1998 1999 2000

1 17 19 44

2 5 0 3

3 6 6 19

4 37 48 110

5 39 34 73

6 2 2 3

7 9 6 9

8 22 26 33

9 8 6 16

10 10 9 11

11 19 15 4

12 5 6 1

13 0 0 1

14 5 0 4

15 0 0 0

16 0 0 0

17 8 16 0

18 32 52 37

19 24 40 21

20 65 90 77

21 48 28 27

24 11 14 27

25 34 30 25

26 41 29 54

27 58 50 60

28 102 66 73

29 74 91 58

30 151 128 82

31 127 133 70

32 145 79 81

33 61 58 79

34 87 75 89

35 77 187 396

36 181 164 178

37 100 77 119

38 49 54 38

39 27 48 43

40 24 13 12

41 3 7 12

42 0 1 0
51

Figure 1. Geographic representation of maximum likelihood estimates of percent contribution to

loggerhead strandings in the Southeastern United States. Abbreviations: SFL=South Florida,

NEFL-NC=Northeast Florida to North Carolina. Figure is reproduced from Bass et al. (199913).
52

Figure 2. Location of the Dry Tortugas, where loggerhead turtles nest.
53

Nesters Size Distribution

0

5

10

15

75-79.9 80-84.9 85-89.9 90-94.9 95-99.9

Straight Carapace Length (cm)

Number

Figure 3 Size distribution of loggerhead turtles nesting in the Dry Tortugas National Park, 1981-

1984. The mean straight carapace length was 90.4 cm (CMTTP3).

N= 31
54

Figure 4. Geographic range of SEAMAP sampling in the Southeast United States. Stratum

number is located in the upper left and number of trawl samples collected in the lower right of

each stratum. Strata are not drawn to scale. Reprinted from SCMRD (2000).
55

Loggerhead Observed Bycatch

YEAR

1990 1992 1994 1996 1998 2000

B

Y

C

A

T

C

H (n

u

m

b

ers

of turtle

s)

0

2

4

6

8

10

12

14

16

18

20

 

YEAR

1990 1992 1994 1996 1998 2000

C

P

U

E

(turtle

s

p

er h

o

ur to

w

with10

0 fo

ot h

e

a

dro

p

e)

0.00

0.05

0.10

0.15

0.20

Figure 5. Observed loggerhead turtle bycatch rates in the SEAMAP analysis data set.
56

Loggerhead Turtles

YEAR

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000

R

E

L

A

TIV

E IN

D

E

X

0.0

1.0

2.0

3.0

Figure 6. Relative standardized abundance indices for loggerhead turtles in SEAMAP

analysis data set with approximate 95% confidence intervals (solid circles) and

observed relative bycatch rates (open diamonds).
57

40

50

60

70

80

90

100

110

0 10 20 30 40 50 60

Age Post-Settlement (yrs.)

Size (cm SCL)

Schmid (1995**)

Schmid (1995*)

Frazer (1987)

Foster (1994)

Braun-McNeill et al. (in prep)

Henwood (1987)

Figure 7. Published von Bertalanffy growth curves (see Table 1 for parameters). Curves were

plotted using the equation y=a-(a-initial size)e-kx . As only post-settlement growth rates are

being considered, 49 cm SCL was used as initial size.

40

50

60

70

80

90

100

110

0 10 20 30 40 50 60

Age Post-Settlement (yrs.)

Size (cm SCL)

Frazer (1987)

Braun-McNeill et al. (in prep)

New Growth Curve

Figure 8. New growth curve generated by adding additional recaptures of turtles > 70 cm SCL to

the data from Braun-McNeill et al (2001). The parameters are a=99.7 and k=0.053. The curve is

shown with curves from Frazer (1987) and Braun-McNeill et al (in prep52) for comparison.

 

52 Braun-McNeill, J., S.P Epperly, L. Avens, and S. Sadove. A Preliminary analysis of growth rates of juvenile

loggerhead (Caretta caretta) sea turtles from North Carolina, U.S.A. Manuscript in preparation.
58

0

5

10

15

20

25

30

45-5050-5555-6060-6565-7070-7575-8080-8585-9090-95

95-100

100-105

Size Category (cm SCL)

Frequency

Added from CMTTP

Braun-McNeill et al.

(in prep)

Figure 9. Size distibution of turtles from mark-recapture studies used to estimate a new von

Bertalanffy growth curve for loggerhead sea turtles from the Southeast U.S.

1 0 12

114

361 328

153

32 1

0

100

200

300

400

65-7070-7575-8080-8585-9090-95

95-100

100-105

Size (cm SCL)

Frequency

Figure 10. Size frequency of nesting loggerheads from the CMTTP database, using only

reported SCL's (no conversions from CCL) and initial captures (no recaptures). Average size is

90.38 cm SCL (SD=5.08). The smallest nester is 68.5 cm SCL and the largest is 105.1 cm SCL.
59

2

2.5

3

3.5

4

4.5

5

5.5

6

-10 0 10 20 30 40 50 60

Age Post-Settment (yrs)

LN(number of turtles at Age x)

Figure 11. Catch curve for 1986-1989 loggerheads sea turtle strandings, zones 1-35. Size-at-age

estimated using the 'New' von Bertalanffy growth curve (see text).
60

Figure 12. Catch curve from Fig 11 with instantaneous mortality rates (z) and annual survival

rate (S) estimated by examining the slope of the declining arm of the catch curve at 3 different

points. A) At the age corresponding to 70 cm SCL. B) At the age corresponding to 90 cm SCL.

C) At the point where the data begin to scatter (Fig. 5).

4

4.5

5

5.5

6

0 5 10 15

Age Post-Settlement

LN(Number at Age X)

y = -0.1129x + 5.888

R

2

=0.6013

P < 0.05

z = 0.113

S = 0.893

3

3.5

4

4.5

5

5.5

6

0 5 10 15 20 25 30 35

Age Post-Settlement

LN(Number at Age X)

y = -0.0733x + 5.5469

R

2

=0.7035

P < 0.05

z = 0.0733

S = 0.929

3

3.5

4

4.5

5

5.5

6

0 5 10 15 20 25

Age Post-Settlement

LN(Number at Age X)

y = -0.0962+5.7743

R

2

=0.779

P < 0.05

z = 0.0962

S = 0.908

A.

B.

C.
61

Model 1

0

0.2

0.4

0.6

0.8

1

SBJ LBJ ADULTS

Stage

Proportion in Stage

Strandings

0.95

0.97

1

Model 2

0

0.2

0.4

0.6

0.8

1

SBJ LBJ ADULTS

Stage

Proportion in Stage

Strandings

0.95

0.97

1

Model 3

0

0.2

0.4

0.6

0.8

1

SBJ LBJ ADULTS

Stage

Proportion in Stage

Strandings

0.95

0.97

1

Model 4

0

0.2

0.4

0.6

0.8

1

SBJ LBJ ADULTS

Stage

Proportion in Stage

Strandings

0.95

0.97

1

Figure 13. The proportion of animals in the three benthic stages, small benthic juvenile (SBL),

large benthic juvenile (LBJ) and adults, predicted by the stable-age distribution of the 4 models.

These resilts are compared to the proportion of animals within each stage based on size from

dead strandings in the southeast U.S. from 1986 to 1989.
62

Stage Elasticities for Lambda=0.95 

0

0.1

0.2

0.3

0.4

0.5

Age 0 Pelagic Small

Benthic

Large

Benthic

Nesting

Adults

Nonnesting

Adults

Stage

Elasticity (summed over 

age classes in stage)

Model 1

Model 2

Model 3

Model 4

Figure 14. Elasticities summed over all ages in stage. Values given are for proportion female

offspring = 0.35 and λ = 0.95.
63

Model 1, 35% female offspring 

0

2000

4000

6000

8000

10000

0 10 20 30 40 50

Time (yrs)

Number of Nesting 

Females

0.95

0.97

1

Model 2, 35% female offspring 

0

500

1000

1500

2000

2500

0 10 20 30 40 50

Time (yrs)

Number of Nesting 

Females

0.95

0.97

Model 3, 35% female offspring 

0

500

1000

1500

2000

2500

3000

3500

0 10 20 30 40 50

Time (yrs)

Number of 

Nesting Females

0.95

0.97

1

Model 4, 35% female offspring 

0

500

1000

1500

2000

2500

3000

3500

0 10 20 30 40 50

Time (yrs)

Number of Nesting 

Females

0.95

0.97

1

Figure 15. Population trajectories for the 4 models. Model runs were initialized with a

population at stable age distribution for the appropriate combination of model and λ, assuming

2000 nesting females. Small benthic juvenile mortality was decreased by 30% and the

population projected based on the new survival rates.
64

Model 1, 50% female offspring

0

4000

8000

12000

16000

20000

0 10 20 30 40 50

Time (yrs)

Number of Nesting 

Females

0.95

0.97

1

Model 2, 50% female offspring

0

1000

2000

3000

0 10 20 30 40 50

Time (yrs)

Number of Nesting 

Females

0.95

0.97

Model 3, 50% female offspring

0

1000

2000

3000

4000

5000

0 10 20 30 40 50

Time (yrs)

Number of Nesting 

Females

0.95

0.97

1

Model 4, 50% female offspring

0

1000

2000

3000

4000

5000

0 10 20 30 40 50

Time (yrs)

Number of Nesting 

Females

0.95

0.97

1

Figure 16. Population trajectories for the same 4 models as in Fig. 14 but with the proportion of

female offspring now set to 0.50 in the fecundity function. Model runs were initialized with a

population at stable age distribution for the appropriate combination of model and λ, assuming

2000 nesting females. Small benthic juvenile mortality was decreased by 30% and the

population projected based on the new survival rates.
65

Model 1, 80% female offspring

0

10000

20000

30000

40000

0 10 20 30 40 50

Time (yrs)

Number of Nesting 

Females

0.95

0.97

1

Model 2, 80% female offspring

0

1000

2000

3000

4000

5000

0 10 20 30 40 50

Time (yrs)

Number of Nesting 

Females

0.95

0.97

Model 3, 80% female offspring

0

2000

4000

6000

8000

10000

0 10 20 30 40 50

Time (yrs)

Number of Nesting 

Females

0.95

0.97

1

Model 4, 80% female offspring

0

2000

4000

6000

8000

0 10 20 30 40 50

Time (yrs)

Number of Nesting 

Females

0.95

0.97

1

Figure 17. Population trajectories for the same 4 models as in Fig. 14 but with the proportion of

female offspring now set to 0.80 in the fecundity function. Model runs were initialized with a

population at stable age distribution for the appropriate combination of model and λ, assuming

2000 nesting females. Small benthic juvenile mortality was decreased by 30% and the

population projected based on the new survival rates.
66

Model 1

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.95 0.97 1

Pre-TED Lambda Value for Sex Ratio = 0.35

Annual 

Population 

Growth Rate

0.35

0.5

0.8

Model 2

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.95 0.97 1

Pre-TED Lambda Value for Sex Ratio = 0.35

Annual 

Population 

Growth Rate

0.35

0.5

0.8

Model 3

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.95 0.97 1

Pre-TED Lambda Value for Sex Ratio = 0.35

Annual 

Population 

Growth Rate

0.35

0.5

0.8

Model 4

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.95 0.97 1

Pre-TED Lambda Value for Sex Ratio = 0.35

Annual 

Population 

Growth Rate

0.35

0.5

0.8

Figure 18. Population growth rates following a 30% reduction in mortality in the small benthic

stage. Each model (1-4) was run at 3 initial values of λ (equal to 0.95, 0.97 and 1.0 for

proportion of female offspring = 0.35) and at three values for proportion of female offspring

(0.35, 0.50 and 0.80).
PART II

STOCK ASSESSMENT OF

LEATHERBACK SEA TURTLES OF

THE WESTERN NORTH ATLANTIC

Nancy B. Thompson

Jeffrey R. Schmid

Sheryan P. Epperly

Melissa L. Snover

Joanne Braun-McNeill

Wayne N. Witzell

Wendy G. Teas

Lisa A. Csuzdi

Ransom A. Myers
68

Table of Contents

PART II. STOCK ASSESSMENT OF LEATHERBACK SEA TURTLES OF THE WESTERN

NORTH ATLANTIC.................................................................................................................... 69

Geographic Range...................................................................................................................... 69

Seasonal Distributions ............................................................................................................... 70

Stock Definition......................................................................................................................... 73

Population Size and Status......................................................................................................... 74

Age and Growth......................................................................................................................... 75

Population Analysis and Vital Rates ......................................................................................... 76

Sex Ratios.................................................................................................................................. 76

Strandings.................................................................................................................................. 77

Trends..................................................................................................................................... 77

Hot Spots................................................................................................................................ 78

Anthropogenic Impacts.............................................................................................................. 79

Pelagic Longline Fisheries ..................................................................................................... 79

Marine Debris Ingestion......................................................................................................... 79

Entanglement.......................................................................................................................... 79

Gill Nets ................................................................................................................................. 80

Trawls..................................................................................................................................... 81

Other Fisheries ....................................................................................................................... 82

Poaching ................................................................................................................................. 83

Boat Strikes ............................................................................................................................ 83

Literature Cited.......................................................................................................................... 84
69

PART II. STOCK ASSESSMENT OF LEATHERBACK SEA TURTLES OF

THE WESTERN NORTH ATLANTIC

Geographic Range

The leatherback turtle, Dermochelys coriacea, is essentially pelagic, inhabiting the open

ocean from hatchling through adulthood, but may venture into coastal waters to feed and

reproduce. The broad thermal tolerance of this species allows for a greater geographic range than

the cheloniid turtles (Paladino et al. 1990). Adult leatherbacks forage in temperate and subpolar

regions from 71° N to 47° S latitude in all oceans (Pritchard and Trebbau 1984) and undergo

extensive migrations to and from tropical nesting beaches between 30° N and 20° S (Starbird et

al. 1993). Juvenile leatherback turtles have been observed from 57° N to 34° S, although turtles

less than 100 cm CCL (curved carapace length) may be limited to regions with water

temperatures above 26° C (Eckert 1999a).

In the Atlantic Ocean (Fig. 1), leatherbacks have been recorded as far north as

Newfoundland and Labrador, Canada (Bleakney 1965, Goff and Lien 1988, James 2000) and

Norway (Brongersma 1972, Willgohs 1957), and as far south as Uruguay and Argentina 

(Pritchard and Trebbau 1984) and South Africa (Hughes et al. 1998). Pelagic coelenterates

(Scyphozoa and Siphonophora) are a major component in the diet of leatherback turtles (Den

Hartog 1980, Den Hartog and Van Nierop 1984) and the occurrence of turtles often corresponds

to concentrations of jellyfish (Leary 1957, Fritts et al. 1983, Collard 1990, Grant et al. 1996,

James 2000).

Female leatherbacks nest from the southeastern United States to southern Brazil in the

western Atlantic (Ruckdeschel and Shoop 1982, Soto et al. 1997) and from Mauritania to Angola

in the eastern Atlantic (Brongersma 1982, Fretey and Malaussena 1991). With the exception of

Gabon (Fretey and Girardin 1989), there is little information on leatherback nesting along the

West African coast other than general descriptions of nesting beaches in Guinea-Bissau (Barbosa

et al. 1998), Sierra Leone (Fretey and Malaussena 1991), Gulf of Guinea islands (Tomás et al.

1999, Graff 19951), and Angola (Hughes et al. 1973, Carr and Carr 1991). The most significant

nesting beaches in the Atlantic, and perhaps the most significant in the world, are in French

Guiana and Suriname (Pritchard and Trebbau 1984). Relatively important nesting sites also

occur in Guyana and Colombia in South America and in Panama and Costa Rica in Central

America (Bacon 1981). Among the Caribbean Islands (Fig. 2), leatherbacks regularly nest on

Dominican Republic, Puerto Rico and the accompanying islands of Culebra and Vieques, St.

Croix in the U.S. Virgin Islands, Trinidad, and Tobago. Occasional to sporadic nesting occurs

throughout the Caribbean, including the mainland countries of Honduras, Mexico, Nicaragua,

and Venezuela and the islands of Barbados, Dominica, Grenada, Guadeloupe, Jamaica,

Martinique, Saint Lucia, and Saint Vincent (Ibid.).

Female leatherbacks typically undergo trans-oceanic migrations after nesting. Tagging

studies in French Guiana have demonstrated that nesting females travel eastward to Ghana, West

 

1

 Graff, D. 1995. Nesting and hunting survey of the turtles of the island of São Tomé. Progress Report July 1995,

ECOFAC Componente de São Tomé e Príncipe, 33 pp.
70

Africa (Pritchard 1976) and northward to Newfoundland, Canada (Goff et al. 1994). Female

turtles tagged in the U.S. Virgin Islands, Columbia, French Guiana, and Costa Rica were found

stranded along the Atlantic and Gulf coasts of the United States (W. Teas personal

communication2). Satellite telemetry was used to track the post-nesting movements of two

leatherbacks from Trinidad (Eckert 1998, Eckert 1999b). Both turtles traveled to approximately

the 45° N latitude; one of which migrated eastward across the Atlantic Ocean before turning

northward to waters off the coast of Spain and France, and the other migrated northward in the

central Atlantic. Both turtles then began moving southward during the last week of November

presumably to foraging areas off the African coast (Eckert 1999b). These migrating leatherbacks

demonstrated a preference for waters between 16-18° C. A free-ranging male was captured and

satellite-tagged off Nova Scotia in early September and traveled to the southern coast of

Newfoundland before returning to Nova Scotian waters in mid-October3. This turtle then began

moving rapidly southeastward through late October before contact was lost approximately 2,200

km east of Virginia, U.S.A.

Seasonal Distributions

Because leatherback turtles display some degree of endothermy (Paladino et al. 1990),

their seasonal distributions extend latitudinally into the western North Atlantic as far north as

Canadian waters. However, these turtles are not homeothermic and as reptiles do demonstrate

some limitations to thermal tolerances as noted previously. As a result, seasonal movements

would be expected and could be over a very large range, including trans-oceanic movements. It

is also assumed that, when they leave the nesting beach as hatchlings, they move to offshore

waters into the pelagia and upon reaching a certain size, utilize coastal and pelagic waters.

James (2000), after examining data from aerial surveys, observer records, and self

reporting from both fishers and whale watchers, determined that leatherback turtles are found in

Western Atlantic Canadian waters off of Nova Scotia and out beyond the 2000 m isobath from

July through October, with a notable peak in August. While the majority of turtles were reported

well within the 200 m isobath and would be considered coastal, sightings and interactions were

reported by fishers out to and beyond the 2000 m isobath coincident with fishing activities. No

size information is available for these turtles, however, photo documentation of turtles feeding at

the surface would imply that these turtles were large, juvenile to adult sized turtles as they were

easily visible from fishing vessels.

Summarizing three years of survey effort off the northeastern U.S. coastal waters, Shoop

and Kenney (1992) described seasonal movements based on changes in turtle density from Cape

Hatteras, N.C. to the Gulf of Maine, including Georges Bank out to the 2000 m isobath. Survey

effort was primarily from seasonal random transect aerial surveys designed to develop density

estimates for mammals and turtles conducted in the late 1970’s, and included to a lesser extent,

data collected by aircraft and ships while in transit for other data collection purposes and

historical data from 1958 forward. Leatherback turtles were reported throughout the study area

 

2 Wendy Teas, National Marine Fisheries Service, SEFSC, Miami, Fla., personal communication (E-mail) to Therese

Conant, National Marine Fisheries Service, PR, Silver Spring, Md., January 14, 2000.

3

 Canadian Wildlife Federation. 2000. Tracking “Sherman” information. http://www.cwf-fcf.org/pages/sherman.htm
71

and included waters beyond the 2000 m isobath as reported by James (2000) for Canadian waters

(Fig. 3). The authors describe a seasonal peak in turtle abundance throughout the study area in

the summer with an increasing density of turtles southward from Maine to N.C. and a

concentration south of Long Island. Fewer turtles were observed in both the spring and fall with

turtles in the spring concentrating at the 2000 m isobath. No turtles were observed in the winter.

In July and August of 1995 and 1998, the NMFS Northeast Fisheries Science Center

(NEFSC) conducted aerial surveys specifically designed to develop density estimates for

leatherback turtles in waters from Maine to the Virginia/North Carolina border and including

Chesapeake Bay and waters off the southeast coast of Nova Scotia and Newfoundland. The

results from these surveys are very similar to those of Shoop and Kenney (1992) from 20 years

earlier, although the NEFSC surveys were limited to the summer. Turtles were observed from

Maine southward and were concentrated from Long Island southward in coastal waters, and out

to the 2000 m isobath; no turtles were observed in Chesapeake Bay (Fig. 3). Turtles have been

reported from the lower Chesapeake Bay as both live and stranded dead (Lutcavage and Musick

1985, Barnard et al. 1989).

In the early 1980’s (1982-1984) the NMFS Southeast Fisheries Science Center (SEFSC)

conducted seasonal aerial surveys to census turtles and mammals from the western boundary of

the Gulf Stream to coastal waters from Cape Hatteras, N.C. to Key West, Florida (Thompson

19844, Schroeder and Thompson 1987) (Fig. 4). Leatherbacks were observed in all seasons with

a notable peak in observations beginning in the spring and continuing through the summer. In the

spring, leatherbacks were evenly distributed throughout the sampling area, including out to the

western boundary of the Gulf Stream, but were more concentrated along the coast. During the

summer, a concentration of sightings off the central east coast of Florida, similar to that for

loggerhead turtles, suggested a concentration of resources in this area. In looking specifically in

this area off the Florida east coast, Schroeder and Thompson (1987) noted that turtles were more

abundant in the summer and tended to concentrate between 20 m and 40 m of depth. Similar

distributions by depth are described by Hoffman and Fritts (1982) from an aerial survey

conducted off the east coast of Florida in August 1980. Thompson and Huang (1993) suggested

that waters at this depth were cooler than nearshore waters and that turtles may in fact use

thermal cues to identify thermal fronts which would concentrate resources. The use of thermal

cues would explain the high densities of leatherbacks that have been observed on occasion

(Knowlton and Weigle 1989).

Bi-monthly aerial surveys conducted in the Gulf of Mexico are described by Fritts et al.

(1983). Sampling areas were approximately 25,000 km2 blocks off of Brownsville, Texas;

Marsh Island, Louisiana; and Naples, Florida. In the Texas block, sampling was completed out

to about 2000 m and for the two other areas, sampling was completed out to about 200 m. No

turtles were observed off of Texas during any survey month. While few turtles were observed in

the other areas, turtles were observed generally in waters less than 100 m off of Louisiana in the

 

4

 Thompson, N.B. 1984. Progress report on estimating density and abundance of marine turtles: results of first year

pelagic surveys in the southeast U.S., unpublished report for stock assessment workshop MMT/7, National Marine

Fisheries Service, SEFSC, Miami, Fla., 59pp.
72

fall only. Turtles were observed in waters off the Florida west coast during the spring, summer,

and winter months.

From 1983-1986, the NMFS Southeast Fisheries Science Center completed seasonal

aerial surveys in coastal waters of the Gulf of Mexico from inshore waters out to the 100 fathom

isobath (Scott et al. 19895). Leatherback turtles were observed in the Gulf of Mexico in the

summer and fall and most were observed east of the Mississippi River delta. This is consistent

with the distribution in the Gulf of Mexico described by Hildebrand (1982) and Fritts et al.

(1983).

From 1996 to 1998, the SEFSC conducted seasonal shipboard and aerial surveys to

census marine mammals and turtles in the Gulf of Mexico (Mullin and Hoggard 20006). Most of

the ship board survey effort was on the continental slope directed at depths between 100 m to

1000 m from Texas to Florida. The focus of the aerial effort was the northeastern Gulf of

Mexico, resulting in the continental shelf off the Florida panhandle being sampled as well as the

slope waters. Leatherback turtles were observed during aerial surveys in both the summer and

winter. In the summer, turtles were observed from the coast to deeper waters slope waters in

excess of 100 m, and in the winter, turtles were concentrated in slope waters from 100 m

outward. Sightings from these surveys and those by Scott et al. (1989)5 are compiled and

presented in Figure 4.

In general, since aerial surveys are limited to observations of large juvenile, subadult and

adult turtles only, any discussion of hypothesized seasonal movement is limited to the larger life

history stages. Aerial survey results suggest that along the Western North Atlantic coast of

North America and within the Gulf of Mexico there are seasonal movements of large juvenile to

adult sized leatherback turtles from the southeastern coast in the spring to the mid-Atlantic and

New England coasts to Canadian waters in the summer. The decrease in sightings in the winter

and fall suggest that turtles may move even further south or farther offshore. In the Gulf of

Mexico, while sightings are infrequent as compared to the Atlantic Ocean, there appears to be a

peak in abundance of turtles in the warmer months, suggesting movement from the Gulf of

Mexico in the colder months, perhaps southward.

Eckert (1999a) suggests that turtles smaller than 100 cm length are restricted to waters of

at least 26°C. This is supported by strandings, turtle carcasses that wash up dead along the coast.

The Sea Turtle Stranding and Salvage Network (STSSN) database7 was examined from 1986-

1999. While turtles less than 100 cm curved carapace length have been reported throughout the

 

5

 Scott, G.P., D.M. Burn, L.J. Hansen and R.E. Owen. 1989. Estimates of bottlenose dolphin abundance in the Gulf

of Mexico from regional aerial surveys. Unpublished report. NMFS-SEFSC-Miami Laboratory – CRD-88/89-07,

Miami, Fla., 59 pp.

6

 Mullin, K.D. and W. Hoggard. 2000. Visual surveys of cetaceans and sea turtles from aircraft and ships, p.111-

322. In R.W. Davis, W.E. Evans, and B. Wursig, eds. Cetaceans, sea turtles and seabirds in northern Gulf of

Mexico: distribution, abundance and habitat associations. Unpublished report. USGS/BRD/CR-1999-0006, OCS

Study MMS 2002-002. Department of Marine Biology, Texas A&M University, Galveston, Texas.

7 Unpublished data. The Sea Turtle Stranding and Salvage Network is a cooperative endeavor between NMFS, other

federal agencies, the states, many academic and private entities, and innumerable volunteers. Data are archived at

the National Marine Fisheries Service Southeast Fisheries Science Center in Miami, Fla.
73

southeast U.S. and Gulf of Mexico, no turtle smaller than 100 cm length has been reported north

of North Carolina (Fig. 5). Seasonally, strandings are higher along the northeast U.S. coast in

the summer and fall, in the winter and spring along the southeast U.S. coast, in the spring along

the western Gulf of Mexico coast, and in the summer along the eastern Gulf of Mexico (Fig. 6).

The strandings data indicate that leatherback turtles are found in the Gulf of Mexico primarily in

the spring and summer which is consistent with results from aerial surveys.

Stock Definition

A primary goal in marine turtle research during recent years has been stock identification,

whereby regional population structures, in terms of nesting females, are characterized by fixed

differences in mitochondrial DNA (mtDNA) haplotypes (Dutton 1996). For leatherbacks,

however, analyses of mtDNA revealed far less structuring of nesting populations on a global

scale than has been observed in cheloniid turtles (Dutton et al. 1999). Nonetheless, a high degree

of genetic subdivision was observed among rookeries in the Pacific, Indian, and Atlantic Oceans.

(Dutton et al. 1999) In the Atlantic, nesting populations on St. Croix and Trinidad exhibited

significantly different haplotype frequencies between each other and among those for mainland

populations in Florida, Costa Rica, and Suriname/French Guiana. (Ibid.) This observation

provides support that nesting females return to their natal beach on these Caribbean islands.

However, rookeries in Florida and Suriname/French Guiana were indistinguishable, and these

Atlantic populations were indistinguishable from a South African nesting colony in the Indian

Ocean, based on mtDNA. (Ibid.)

It is, as for all turtles, impossible in the field to distinguish animals by nesting population.

The presence of some rare haplotypes identified from leatherback strandings in Georgia suggests

that some are animals from Costa Rica or Trinidad (P. Dutton personal communication8).

Preliminary results of analysis using new nuclear DNA (nDNA:microsatellites) markers reveals

that the South African populations are distinct from the Caribbean, suggesting that the lack of

differentiation with mtDNA is due to recent shared ancestry, rather than ongoing gene flow

(Ibid.). On a regional scale, microsatellite data show that the Trinidad and French

Guiana/Suriname populations are homogeneous, in contrast to the mtDNA data. This indicates

that despite their relative proximity, mtDNA gene flow may be restricted by natal homing on the

part of females, while at the nuclear level, gene-flow is facilitated by males who most likely

encounter and mate with females from both populations (Ibid.). Genetic analysis of samples

from the West African populations is ongoing, with preliminary data suggesting that (like the

South Africa rookery) they are indistinguishable at the mtDNA level from some Caribbean

populations, but distinct at the nuclear level (Ibid.). The loss of nesting populations in the St.

Croix region and Trinidad would eliminate most of the detected mtDNA variation in the

Atlantic, although these populations represent less than 10% of nestings in this region (Dutton et

al. 1999).

 

8

Peter Dutton, National Marine Fisheries Service, SWFSC, La Jolla, Ca., personal communication (phone) to

Sheryan Epperly, National Marine Fisheries Service, SEFSC, Miami, Fla.
74

Population Size and Status

Since nesting females are the most accessible stage in the marine turtle life history,

counts of females or their nests provide the best available index for the status of marine turtle

populations (National Research Council 1990). Other methods for censusing marine turtle

populations include counts from aerial surveys, carcass strandings, and catch per unit effort in

fishing gear, but counts of females and their nests are most commonly used to delineate longterm (e.g., longer than a decade) population trends.

Pritchard (1971) first estimated the worldwide leatherback population to be between

29,000 and 40,000 breeding females, but later refined his estimate to approximately 115,000

(Pritchard 1982). Ross (1982) provided a much more conservative estimate of 14,325 nesting

females. Spotila et al. (1996) estimated a global population of 34,500 females, with a lower limit

of about 26,200 and an upper limit of about 42,900. These latter authors also suggested that the

species as a whole was declining and that local populations were in danger of extirpation.

Pritchard (1996) cautioned that the conclusions of Spotila et al. (1996) were based on unproven

assumptions and short-term trends at nesting beaches that are now protected. Nonetheless, all

aforementioned authors have noted dramatic declines in nesting populations of leatherbacks in

the Pacific Ocean, but apparently stable or increasing nesting populations in the Atlantic. Dutton

et al. (1999) have interpreted genetic results from mtDNA sequences to indicate an evolutionary

history of global extinction followed by relative rapid recolonization in terms of geological time

scales.

Spotila et al. (1996) provided the most recent summary of the status of nesting

leatherback turtles in the Atlantic Ocean. The largest nesting colonies of leatherbacks occur on

the coasts of French Guiana (4,500-7,500 females per year) and Suriname, South America (600-

2,000 females per year) and Gabon, West Africa (1,276-2,553 females per year. Smaller colonies

occur among the Caribbean Islands, but constitute a significant aggregation when considered

collectively (1,437-1,780 females per year).

Data collected at St. Croix and southeast Florida clearly indicate increasing numbers of

nests for the past twenty years, though it should be noted that there was also an increase in the

survey area in Florida over time (Boulon et al. 1996, Meylan et al. 1995, Florida Fish and

Wildlife Conservation Commission 20009

) (Figs. 7, 8). There was an annual increase in the

number of leatherback nests for all Suriname beaches during the early to mid-1980's with a

subsequent annual decline since then to the present (Fig. 7). It is not known if there is a natural

cycle in annual nesting. Schulz (1975) describes cycles of 10 years in the accretion and erosion

of Guyana beaches which might explain the cycle observed in nesting over the past 30 years.

Analysis of annual trends in numbers of nests is further complicated by the fact that, in the

absence of data for a given year, the number of nests were estimated from one nesting beach to

another giving a correlation in the number of nests among the three localities. Ya:lima:po and

Galibi beaches are separated by the estuary of the Marowijne River (approximate width of 8 km),

and it has been suggested that leatherback females may shift their nesting efforts to Suriname

beaches owing to erosion at those in French Guiana (Pritchard and Trebbau 1984, Reichart and

 

9

 Florida Fish and Wildlife Commission. 2000. Southeast Florida Nesting Activity of the Leatherback Turtle. Florida

Marine Research Institute. www.fmri.usf.edu/turtle/nesting/seleath.htm
75

Fretey 1993). Data collected at Ya:lima:po during 1992-97 suggest a steady decline in the

number of nests, and, if turtles are shifting their nesting efforts, one would expect a comparable

number of nests to occur elsewhere during this period. Such a trend is not apparent, but the data

for Galibi during 1990-1994 and 1996-1997 were estimated. A decline in leatherback nests was

also observed from 1985 to 1992 at the beaches of Matapica, located west of Galibi. Therefore,

given these data, it is not clear whether the recent decline recorded at Ya:lima:po represents a

real decrease in the nesting population or a possible shift to other beaches that somehow has not

been observed or reported.

Nesting data from selected beaches were analyzed to estimate changes in nesting activity

over time for leatherbacks (Appendix 1). The data were limited to sites where surveys were

believed to have been relatively constant over time. It is an unweighted analysis and does not

consider the beaches’ relative contribution to the total nesting activity of the subpopulation and

must be interpreted with some caution. This analysis treats nesting beaches as random samples

from the total. For analysis of regional trends, nesting data from leatherbacks was separated into

three areas: South America, St. Croix (U.S. Virgin Islands), and Florida.

For data from 1979 on from St. Croix the trend is increasing at 7.5% per year (r = 0.078;

SE = 0.014). For data from 1979 on from Florida, several models were applied and the resulting

trends ranged from 9.1% per year (r = 0.095; SE = 0.049) to 11.5% per year (r = 0.122; SE =

0.053). Only data from 1987 and on were used for South America. Depending on how the error

variance was handled in the model, results here showed declining trends at –17.3% per year (r =

-0.190; SE = 0.06) and –15.0% per year (r = -0.163; SE = 0.041). See Appendix 1 for details of

the analyses and specific beach site used.

It is important to note that nesting trends may reflect trends in adult females in a

population however it may not predict overall population trends well as adult females may

account for only a small proportion of the population.

Age and Growth

The duration between hatchling and adulthood is unknown for leatherback turtles. The

only information on the growth of leatherback turtles is from captive juvenile specimens, but

none have been raised to maturity as captive leatherbacks experience high mortality. The limited

data available for captive specimens suggest the leatherback grows much more rapidly than the

cheloniid turtles and sexual maturity may therefore be obtained in a relatively short time (2-3

years; (Pritchard and Trebbau 1984). Patterns of skeletal growth support this hypothesized

duration, prompting Rhodin (1985) to propose that leatherback turtles may attain sexual maturity

in 3-6 years. Zug and Parham (1996) conducted a skeletochronological analysis of specimens

collected from the eastern Pacific and calculated an average age to maturity of 13-14 years. For

conservation management purposes, the authors indicated that 9 years is a likely minimum age to

maturity for leatherback turtles based on the youngest adult in their sample. Zug and Parham

(1996) also noted that the carapace lengths of their east Pacific samples were significantly

smaller than those from the Atlantic, as suggested by Pritchard and Trebbau (1984), but

emphasized the difficulties in comparing different populations owing to the variety of measuring

techniques used by different investigators and the lack of conversions between techniques. A

short generation time suggests that declines in population should be measurable on nesting
76

beaches relatively rapidly. The shorter the generation time, the more likely protective measures

will quickly stabilize and reverse declines in populations.

Population Analysis and Vital Rates

In an analysis of the literature, there is a reasonable amount of information on leatherback

sea turtle fecundity (Table 1) and an estimate of this value could be made for incorporation into a

population model. However, in previous sea turtle models, fecundity and the egg/hatchling stage

typically have low elasticities, in other words, changes in these values has little impact on

population trends (Crouse et al. 1987, Crowder et al. 1994). Juvenile and adult survival rates

and age-at-maturity are the important parameters and as yet there is little information for these

vital rates. As discussed in the section on Age and Growth, there is a great deal of uncertainty

about individual leatherback growth rates. Estimates span from as little as 3-6 years (Rhodin

1985) to 13-14 years (Zug and Parham 1996). For survival rates, Dutton et al. (1999) provide an

estimate of adult mortality based on whether or not a tagged female returned to nest within 5

years (considered the maximum remigration interval). The range in their estimates is extreme,

19 to 49%. We have no information on any other vital rates, particularly lacking is any

information about the in-water juvenile stages.

Given the degree of uncertainty in what information there is, combined with a lack of any

information about the in-water stages, and what is not yet known about the life history of the

leatherback sea turtle, it is not possible to proceed with a stock assessment based on a

quantitative population model. Specific directions of research needed are:

• Further studies on age and growth with emphasis on the juvenile stage/s.

• A comprehensive analysis of adult mortality based on nesting beach surveys.

• An understanding of habitat utilization by all stages with consideration of the habitat

specific mortality factors.

Sex Ratios

Studies at nesting beaches have shown that the sex ratio for hatchling leatherback turtles

varies with location, season, and year (Leslie et al. 1996). In Suriname, Mrosovsky et al. (1984)

determined that more males were produced at the beginning of the nesting season during the

wetter, cooler months and more females at the end during the drier, warmer months. An overall

sex ratio of 49% female was calculated, but the authors cautioned that sand temperatures on the

beach and distribution of the nests might vary from year to year. Dutton et al. (1992)10 proposed

a similar seasonal shift in the sex ratio of hatchlings at St. Croix and estimated an overall sex

ratio of 60-70% female. Perhaps this female biased ratio has resulted in the increased numbers of

adult females nesting at this locality as illustrated in the previous section on Population Size and

Status. Leslie et al. (1996) estimated male biased sex ratios for leatherback nests at Tortuguero,

Costa Rica, but predicted a shift to female biased ratios when considering metabolic heating

within the nest.

 

10 Dutton, P.H., D.L. McDonald, and R.H. Boulon. 1992. Tagging and nesting research on leatherback sea turtles

(Dermochelys coriacea) on Sandy Point, St. Croix, U.S. Virgin Islands. Annual Report to the U.S. Fish and Wildlife

Service, 26pp.
77

The Sea Turtle Stranding and Salvage Network database7 was examined to determine the

sex ratio of leatherback sea turtles found in the waters off of the U.S. Gulf of Mexico and

Atlantic coasts. It is possible that adult females utilize nearshore habitats in greater proportion

than adult males due to the necessity of coming ashore to nest, whereas juvenile habitat

utilization is not likely to be sex dependent. To obtain an unbiased estimate, only records for

juveniles were included in the analysis where sex was determined via examination of the gonads.

An animal was considered a juvenile if it was less than 145 cm CCL (Eckert 1999a), and records

were excluded for animals greater than or equal to this size. In addition, many of the STSSN

records for leatherback turtles list only straight-line carapace length (SCL) and many of these are

known to be inaccurate owing to the limited size range of measuring calipers. To be

conservative, records greater than or equal to 80 cm SCL (80 cm being the maximum length

measured by most calipers available to stranding observers) were excluded when only a SCL was

recorded. Of the juvenile leatherback sea turtles that stranded along the U.S. Gulf of Mexico and

Atlantic coasts between 1980 and 1999, 28 were identified by necropsy as female and 20 as male

giving a sex ratio of 1.4F:1.0M (or 58.3% female).

Strandings

Complete strandings information for leatherback sea turtles are provided in Table 2. As

with the analysis of strandings of loggerhead sea turtles (TEWG 1998, 2000), the leatherback

strandings used excluded incidental captures, post-hatchlings, or cold-stunned animals. Figure 9

depicts the leatherback strandings reported by area and season, 1986-1999. Figure 10 shows the

statistical zones for which sea turtle strandings are reported. Monitoring effort is not directly

comparable between zones but has been reasonably consistent over this period. There is no

survey effort in zones 15 and 16, due to inaccessibility of shoreline, and coverage is low in zones

13 and 14. In the eastern Gulf of Mexico (zones 1-12, partial 24-25), survey coverage is low in

zones 1, 3, 6, and 7 due to inaccessibility and zone 2 has very little land mass. The lack of data

from these zones may or may not reflect a lack of strandings. Along the southeast U.S. Atlantic

coast, coverage is also low in zones 24 and 25. In the northeastern U.S. Atlantic, survey

coverage is less rigorous. However, high human densities along the coast in this area suggests

most strandings will get reported. This is not true for inshore waters, such as the Chesapeake

Bay and Pamlico and Core Sounds of North Carolina, where many strandings likely go

unreported.

Trends

Table 2 shows leatherback strandings by region for the years 1986-1999. Over this 14-

year period, the northeast (45%) and the southeast (42%) accounted for the majority of the

strandings totals, with 13% of the strandings occurring in the Gulf of Mexico. In the northeast,

strandings peaked in 1987 (80), 1993 (80) and again in 1995 (117 - a 46% increase over the 1987

and 1993 strandings' peaks). Most of the leatherback strandings (95%) in the northeast occurred

in the summer and fall, with fewer strandings in the winter (3%) and spring (2%). Strandings in

the southeast increased from 1986-1991, then began a gradual decrease until 1999 when levels

were elevated again. Leatherback strandings in the southeast were highest during the spring

(45%) and somewhat equally represented during the summer (15%), fall (21%), and winter

(19%). Strandings in the Gulf of Mexico remained relatively low throughout the time period
78

with only minor peaks in strandings in 1989 in the eastern Gulf and 1995 and 1999 in the

western Gulf. Overall strandings in the Gulf were much higher in the spring and summer,

accounting for 88% of the total number of strandings in that area.

Hot Spots

The majority of leatherback strandings were about equally divided between the northeast

(45%) and the southeast (42%). One potential source for the strandings in the northeast might be

entanglement in fishing gear which seems to pose more of a problem in the northeast than in

other states. According to STSSN strandings data 7 for 1980-1999, 62% (N=48) of stranded

leatherback sea turtles which had evidence of entanglement in fishing gear, occurred in northern

states (Virginia to Maine) while 18% (N=14) occurred in southern states (Florida's east coast to

North Carolina) and 19% (N=15) occurred in Gulf states (Florida's west coast to Texas).

Entanglement was cited as the major cause of leatherback strandings in Massachusetts (Prescott

1988; R. Prescott personal communication11) and New York (S. Sadove personal

communication12) (See entanglement under Anthropogenic Impacts section). Likewise,

ingestion of marine debris may pose more of a threat to leatherbacks in the northeast than

anywhere else in the United States. An analysis of the STSSN strandings data 7 from 1980-1999

revealed a majority (72%) (N=26) of stranded leatherback sea turtles which had ingested marine

debris or fishing gear occurred in northern states (Virginia to Maine) than in southern (Florida’s

east coast to North Carolina)(25%) (N=9) or Gulf states (Florida’s west coast to Texas) (3%)

(N=1). (See marine debris ingestion under Anthropogenic Impacts section) Most of the

leatherback strandings in the southeast (66%) (N=435) occurred during the spring and fall while

relatively high strandings in the western Gulf (76%) (N=97) occurred during the spring,

coinciding with nearshore shrimp trawling activity. In 1995, the NMFS, in cooperation with the

U.S. Fish and Wildlife Service, Florida, Georgia and South Carolina, developed the Leatherback

Contingency Plan in order to reduce leatherback mortality in shrimp trawls. This plan enabled

the NMFS to establish leatherback conservation zone regulations (50 CFR 223.206) in 1995

which stipulated the use of weekly aerial surveys to enumerate concentrations of leatherback sea

turtles along the coast from Cape Canaveral, Florida to the N.C./Va. border. If concentrations of

leatherbacks were high (10 sea turtles/50 nautical miles), then the area was closed to shrimp

trawlers not using a TED modified with the leatherback exit opening. Although the Leatherback

Contingency Plan was developed in order to prevent leatherback sea turtles migrating northward

from becoming incidentally captured in shrimp trawlers, high strandings of leatherbacks in

Florida and Texas have prompted the NMFS to impose emergency measures to protect

leatherback sea turtles in additional areas and times. From October 28 to November 29, 1999, a

total of 15 leatherback turtles washed ashore in southern Florida (statewide annual number of

leatherbacks strandings has averaged 23 over the past 10 years). Consequently, the NMFS

imposed a 30 day restriction requiring all shrimp vessels operating in the area to use a TED with

an escape opening large enough to exclude leatherback turtles (64 FR 69416-69418, December

 

11 Robert Prescott, Massachusetts Audubon Society’s Wellfleet Bay Wildlife Sanctuary, South Wellfleet, Mass.,

personal communication (E-mail) to Joanne Braun-McNeill, National Marine Fisheries Service, SEFSC, Beaufort,

N.C., December 1, 2000.

12 Sam Sadove, Long Island University, Southampton College, Southampton, NY, personal communication (phone)

to Joanne Braun-McNeill, December 6, 2000.
79

13, 1999). Likewise, during the spring of 2000, after a record 9 leatherbacks stranded along the

Texas coast in a 6 week period (statewide annual number of leatherbacks strandings has

averaged 12 over the past 6 years), the NMFS required shrimpers trawling off the coast of Texas

to use a TED with an escape opening large enough to exclude leatherbacks for a 30 day period

(65 FR 24132-24134, April 25, 2000).

Anthropogenic Impacts

Pelagic Longline Fisheries

See Part III.

Marine Debris Ingestion

Leatherback sea turtles might be more susceptible to marine debris ingestion than other

species due to their pelagic existence and the tendency of floating debris to concentrate in

convergence zones which adults and juveniles use for feeding areas and migratory routes

(Lutcavage et al. 1997; Shoop and Kenney 1992). Investigations of the stomach contents of

leatherback sea turtles revealed that a substantial percentage (44% of the 16 cases examined)

contained plastic (Mrosovsky 1981). Along the coast of Peru, intestinal contents of 19 of 140

(13%) leatherback carcasses were found to contain plastic bags and film (Fritts 1982). The

presence of plastic debris in the digestive tract suggest that leatherbacks might not be able to

distinguish between prey items and plastic debris (Mrosovsky 1981). Balazs (1985) speculated

that the object may resemble a food item by its shape, color, size or even movement as it drifts

about and induce a feeding response. Although necropsies conducted between 1980 and 1992 by

the Sea Turtle Stranding and Salvage Network (STSSN)7 participants showed that leatherbacks

were more likely to ingest marine debris in the southeastern U.S., it was noted that leatherbacks

also consume plastic bags in the northeastern U.S. (Witzell and Teas 1994). When more recent

data were included through 1999, the majority of leatherbacks which had ingested marine debris

or fishing gear occurred from Virginia through Maine (see Hotspots). Of the 33 leatherbacks

that were necropsied in New York, plastic bags were found in 10 animals (Sadove and Morreale

1990).

Entanglement

Sea turtles entangled in fishing gear generally have a reduced ability to feed, dive, surface

to breathe or perform any other behavior essential to survival (Balazs 1985). They may be more

susceptible to boat strikes if forced to remain at the surface, and entangling lines can constrict

blood flow resulting in necrosis (Ibid.). Leatherbacks seem more likely to become entangled in

fishing gear than other species. Leatherback entanglement in longline fishing gear is discussed

in Part III, Chapter 7. The fish trap fishery, operating in Rhode Island from March through

December, is known to capture sea turtles. Leatherbacks have been captured alive in large fish

traps set off Newport - most are reported to be released alive (Anonymous 199513). Of the

 

13 Anonymous. 1995. State and federal fishery interactions with sea turtles in the mid-Atlantic area, p.1-12. In

Proceedings of the Workshop of the Management and Science Committee of the Atlantic States Marine Fisheries

Commission July 17-18, Richmond, Virginia.
80

approximately 20 live, entangled sea turtles reported in the National Marine Fisheries Service

(NMFS) Northeast Region Stranding Network, the majority are leatherback sea turtles entangled

in pot gear in New England waters. The leatherbacks become entangled in the buoy line and/or

ground line, possibly mistaking the buoys for cannonball jellyfish (Anonymous 199513).

Massachusetts, Rhode Island, Connecticut, and New York all have active lobster pot fisheries

which can entangle leatherbacks (Anonymous 199513). Entanglement in lobster pot lines was

cited as the leading determinable cause of adult leatherback strandings in Cape Cod Bay,

Massachusetts (Prescott 1988; R. Prescott personal communication11). During the period 1977-

1987, 89% of the 57 stranded adult leatherbacks were the result of entanglement (Prescott 1988).

Likewise, during the period 1990-1996, 58% of the 59 stranded adult leatherbacks showed signs

of entanglement (R. Prescott personal communication11). Many of the stranded leatherbacks for

which a direct cause of death could not be documented showed evidence of rope scars or wounds

and abraded carapaces, implicating entanglement (Ibid.). Entanglement in fishing gear, namely

the lobster fishery, was cited as the major cause of leatherback and loggerhead sea turtle

strandings in New York (S. Sadove personal communication12). In the Southeast U.S. MidAtlantic waters, the blue crab fishery is another potential source of leatherback entanglement. In

North Carolina, two leatherback sea turtles were reported entangled in a crab pot buoy inside

Hatteras Inlet (D. Fletcher personal communication14). A third leatherback was reported

entangled in a crab pot buoy in Pamlico Sound off of Ocracoke . This turtle was disentangled

and released alive, however, lacerations on the front flippers from the lines were evident (D.

Fletcher personal communication15). Leatherbacks become entangled in Florida’s lobster pot

and stone crab fisheries also, as documented on stranding forms 7. Although not documented as

the major cause of leatherback strandings in the U.S. Virgin Islands for the time period 1982 to

1997 (1 of 5 leatherbacks stranded due to entanglement out of a total of 122 strandings) (Boulon

2000), leatherbacks have been observed with their flippers wrapped in the line of West Indian

fish traps (R. Boulon personal communication16). STSSN leatherback strandings7 for 1980-1999

documented significantly more strandings as a result of entanglement in the northern states

(Virginia to Maine)(62%) than southern (Florida’s east coast to North Carolina)(18%) or Gulf

states (Florida’s west coast to Texas) (19%). The majority (67%) of these strandings were the

result of being entangled in crab or lobster trap lines; additional sources of entanglement

included being entangled in fishing line or nets or having a hook in the mouth or flipper.

Gill Nets

Leatherback sea turtles also are vulnerable to capture in gill nets. Gill net fisheries

operating in the nearshore waters of the mid-Atlantic states are likely to take leatherbacks since

these fisheries and leatherbacks can co-occur, however, there is very little quantitative data on

capture rate and mortality. According to the NMFS Northeast Fisheries Science Center Fisheries

 

14 David Fletcher, N.C. Division of Marine Fisheries, Ocracoke, N.C., personal communication to Sheryan Epperly,

National Marine Fisheries Service, SEFSC, Beaufort, N.C., September 19, 1990.

15 David Fletcher, N.C. Division of Marine Fisheries, Ocracoke, N.C., personal communication to Sheryan Epperly,

National Marine Fisheries Service, SEFSC, Beaufort, N.C., September 3, 1989.

16 Rafe Boulon, Virgin Islands National Park, U.S.V.I., personal communication (E-mail) to Joanne Braun-McNeill,

National Marine Fisheries Service, SEFSC, Beaufort, N.C., December 7, 2000.
81

Observer Program, in 1994, 2 live and 2 dead leatherback sea turtles were reported incidentally

captured in drift gill nets set in offshore waters from Maine to Florida (with 56% observer

coverage); in 1995, 15 live and 12 dead leatherback sea turtles were reported (70% coverage); in

1996 1 live leatherback was reported (54% coverage); in 1998, 3 live and 2 dead leatherbacks

were reported (92% coverage)17.

The NMFS Northeast Fisheries Science Center, Fisheries Observer Program also had

observers on the bottom coastal gill net fishery which operates in the mid-Atlantic, but no takes

of leatherback sea turtles were observed from 1994-1998. Observer coverage of this fishery,

however, ranged from <1% to 5%. In North Carolina, a leatherback was reported captured in a

gill net set in Pamlico Sound at the north end of Hatteras Island in the spring of 1990 (D.

Fletcher personal communication14). It was released alive by the fishermen after much effort.

Five other leatherbacks were released alive from nets set in North Carolina during the spring

months: one was from a net (unknown gear) set in the nearshore waters near the North

Carolina/Virginia border (1985)7; two others had been caught in gill nets set off of Beaufort Inlet

(1990)18; a fourth was caught in a gill net set off of Hatteras Island (1993)7; and a fifth was

caught in a sink net set in New River Inlet (1993) (Ibid.). In September of 1995, however, two

dead leatherbacks were removed from a large (11 inch) monofilament shark gill net set in the

nearshore waters off of Cape Hatteras, North Carolina (Ibid.).

Gill nets set in northwest Atlantic coastal waters are reported to routinely capture

leatherback sea turtles (Goff and Lien 1988; Goff et al. 1994; Anonymous 199619).

Leatherbacks often drown in fish nets set in coastal waters of Sao Tome, West Africa

(Castroviejo et al. 1994; Graff 19951). Gill nets are one of the suspected causes for the decline in

the leatherback sea turtle population in French Guiana (Chevalier et al. 1999).

In the waters of coastal Nicaragua, gill nets targeting green and hawksbill turtles also

incidentally catch leatherback turtles (Lagueux et al. 1998). An estimated 1,000 mature female

leatherback sea turtles are caught annually off of Trinidad and Tobago with mortality estimated

to be between 50-95% (Eckert and Lien 1999). Many of the turtles do not die as a result of

drowning, but rather because the fishermen butcher the turtles in order to get them out of their

nets (Ibid.).

Trawls

The National Research Council Committee on Sea Turtle Conservation identified

incidental capture in shrimp trawls as the major anthropogenic cause of sea turtle mortality

(National Research Council 1990). Although federal regulations requiring TEDs in trawls were

 

17 Unpublished data, National Marine Fisheries Service, NEFSC, Woods Hole, Mass., Personal Communication

(Fax) from Richard Merrick to Joanne Braun-McNeill, National Marine Fisheries Service, SEFSC, Beaufort, N.C.,

November 28, 2000.

18 Unpublished data, Joanne Braun-McNeill, National Marine Fisheries Service, SEFSC, Beaufort, N.C., personal

communication.

19 Anonymous. 1996. North Atlantic leatherback turtle workshop. November 22, 1996. Life Sciences Center,

Dalhousie University, Halifax, Nova Scotia, 266pp.
82

fully implemented in May 1991 and U.S. sea turtle strandings have declined since then (Crouse,

Crowder and Heppell unpubl. as cited by Crowder et al. 1995), trawls equipped with TEDs are

still taking large immature and adult loggerhead and green sea turtles (Epperly and Teas 199920)

and leatherbacks (Henwood and Stuntz 1987).

As leatherbacks make their annual spring migration north, they are likely to encounter

shrimp trawls working in the nearshore waters off the Atlantic coast. Although the Leatherback

Contingency Plan was developed to protect migrating leatherbacks from being incidentally

captured and killed in shrimp trawls (see summary of these regulations in the Strandings

Section), the NMFS has also had to implement additional leatherback protections outside of the

contingency plan, through emergency rules in response to high strandings of leatherbacks in

Florida and Texas. Because of these high leatherback strandings occurring outside the

leatherback conservation zone, the lack of aerial surveys conducted in the fall, the inability to

conduct required replicate surveys due to weather, equipment or personnel constraints, and the

possibility that a 2 week closure was insufficient to ensure that leatherbacks had vacated the area,

the NMFS published an Advanced Notice of Proposed Rulemaking in April 2000 (65 FR 17852-

17854, April 5, 2000) indicating that NMFS was considering publishing a proposed rule to

provide additional protection for leatherback turtles in the shrimp fishery. In the interim, the

NMFS has requested all shrimp trawlers to use TEDs modified to release leatherback sea turtles

along the east coast of Florida to the Georgia/Florida border through the end of March 2000

(December 11, 2000 NR00-06121). This request would likely protect leatherbacks during the

winter Florida shrimp season that tend to stay in this area until the start of the spring migration.

Turtle excluder devices are required in the Mid-Atlantic winter trawl fishery for summer

flounder in waters south of Cape Charles, Va., however, these small TEDs can not exclude

leatherback sea turtles. Although not documented, it is suspected that this fishery may take

turtles to the north of Cape Charles where TEDs are not required. In Rhode Island, leatherbacks

are occasionally taken by trawlers targeting scup, fluke and monkfish in state waters

(Anonymous 199513). It is likely that leatherbacks may be taken by trawlers operating off of

other Mid-Atlantic waters. Observers on board shrimp trawlers operating in the northeastern

region of Venezuela documented the capture of 48 sea turtles, of which 6 were leatherbacks,

from 13, 600 trawls (Marcano and Alio 2000). They estimated annual capture of all sea turtle

species to be 1370 with an associated mortality of 260 turtles, or about 19%.

Other Fisheries

In North Carolina, one leatherback was captured in a channel net set in Core Sound while

another was hooked by someone fishing with rod and reel in Core Sound22; both of these

 

20 Epperly, S.P. and W.G. Teas. 1999. Evaluation of TED opening dimensions relative to size of turtles stranding in

the Western North Atlantic. U.S. Department of Commerce, National Marine Fisheries Service SEFSC Contribution

PRD-98/99-08, Miami, Fla, 31pp.

21 News release, NR00-061, National Marine Fisheries Service, Southeast Regional Office, St. Petersburg, Fla.,

December 11, 2000.

22 Unpublished data, Joanne Braun-McNeill, National Marine Fisheries Service, SEFSC, Beaufort, N.C., personal

communication.
83

incidental captures occurred during the late spring when leatherbacks are migrating north. In

Virginia, two leatherbacks have been reported involved with pound nets during the summer, one

was entangled in the leader and one was inside the net; both were released alive7. In Sao Tome,

West Africa, hawksbill, green and leatherback sea turtles are captured and eaten (Graff 19951).

Fisheries (turtle nets, spear gun, longlines) targeting green and hawksbill turtles in St. Vincent

and the Grenadines will catch a few leatherback sea turtles also each year (Scott and Horrocks

1993).

Poaching

In the U.S. Virgin Islands, some poaching is still occurring, both of juveniles and adults

in the water and of the eggs on the beach (R. Boulon personal communication16). In a summary

of strandings data from 1982 - 1997 for St. Croix, St. Thomas and St. John, all leatherback

strandings (5 out of a total of 122 strandings) were reported on St. Croix, and most (4 of the 5

strandings) were the result of poaching (Boulon 2000). Leatherback nests are commonly

relocated at Sandy Point on St. Croix to reduce the nest loss due to beach erosion, but also to

protect nests from poaching (R. Boulon personal communication16). There have been a few

recorded cases of fishermen killing leatherbacks in Puerto Rico, however, most of the poaching

is of the eggs (C. Diez personal communication23).

In Ghana, it is estimated that two-thirds of the leatherback sea turtles that come up on the

beach are killed by the local fishermen24. Nesting leatherback turtles are captured and eaten in

Sao Tome, West Africa (Castroviejo et al. 1994, Graff 19951), St. Kitts and Nevis (Eckert and

Honebrink 1992), and St. Lucia (d’Auvergne and Eckert 1993). The illegal harvest of

leatherback eggs is considered to be a serious threat to the nesting population at Tortuguero,

Costa Rica (Campbell et al. 1996). They estimate that at least 75% of all clutches from the

beaches near Tortuguero, Parismina, and Jalova were harvested (Ibid.). From aerial surveys

conducted in 1982, it was apparent that the fishermen were killing most of the turtles nesting on

Almond Beach, in the North-West District of Guyana, and likely that all of the eggs were being

harvested (Hart 1984). An estimated 80% of nesting females are killed each year in Guyana

(Pritchard 198625).

Boat Strikes

Boat strikes are not a significant source of mortality for leatherbacks in the northeast U.S.

(S. Sadove personal communication12) or in the Caribbean (R. Boulon personal

communication16). According to 1980-1999 STSSN strandings data7, however, the number of

leatherback strandings involving boat strikes or collisions (231) was considerably greater than

the number of strandings involving entanglement in fishing gear (81), ingestion of marine debris

(36) or some kind of intentional interaction - gaff wounds or rope deliberately tied to a flipper

(21) combined. It should be noted that it is not known whether the boat strikes were the cause of

 

23 Carlos Diez, Programa de Especies Protegidas DRNA-PR, San Juan, Puerto Rico, Personal Communication

(Phone) to Joanne Braun-McNeill, National Marine Fisheries Service, SEFSC, Beaufort, N.C., December 7, 2000.

24 BBC News, Saving the giant sea turtle. Africa Section:Thursday, 20 July, 2000.

25 Pritchard, P.C.H. 1986. Unpublished manuscript, Sea turtles in Guyana. Florida Audubon Society, 14pp.
84

death or whether they occurred post-mortem. Interestingly, strandings as a result of boat strikes

were equally represented (45%) in northern states (Virginia to Maine) and southern states

(Florida’s east coast to North Carolina), with Gulf states (Florida’s west coast to Texas)

contributing 10%. The states where the majority of boat strike related strandings occurred were

the Atlantic ocean side of Florida (20%), North Carolina (17%) and New Jersey (15%).

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Table 1. Summary of vital rates for leatherback sea turtles.

Source Remigration

Rates

Nests/yr Yolked

Eggs/Nest

Hatch

success

Sex Ratio Size of

Nesters

Adult

Mortality

Location

Boulon et al. 1996 34.1% 5.26 79.7 67.1% St. Croix, USVI

McDonald and Dutton

1996

Revised above

to 48.5%

“

Dutton and McDonald

1995

59.9-67.9% “

Eckert 1987 4.9 “

Dutton et al. 1999 19-49% “

Hughes 1996 30.5-33.7% 159.6-162.2

cm

South Africa

Eckert 2000 5-7 79-90 Caribbean

Campbell et al. 1996 80.2 159.9 cm Costa Rica,

Caribbean

Leslie et al. 1996 80-86 42% 156.2 cm “

Steyermark et al.

1996

4.9-5.1 44% 144.4-147.6

cm CCL

“

Chevalier et al. 1999 2.5yrs avg

interval

7.5 French Guiana

Girondot and Fretey

1996

7.52 154.6 cm

SCL

“

Hoekert et al. 1998 22-35%

20%

French Guiana

Surinam

Mrosovsky et al. 1984 49%F Surinam

Binckley et al. 1998 100%F

93.5%F

74.3%F

Costa Rica, Pacific

Godfrey et al. 1996 35-70%F

avg=53.4%F
93

Table 2. Leatherback strandings by region, 1986-19997.

 Year Northeast

U.S.

Southeast

U.S.

Eastern Gulf Western Gulf Total

1986 34 14 2 10 60

1987 80 64 1 2 147

1988 39 30 2 9 80

1989 25 54 19 6 104

1990 31 57 4 10 102

1991 60 78 3 5 146

1992 40 69 9 3 121

1993 80 45 6 10 141

1994 30 35 4 3 72

1995 117 53 6 20 196

1996 33 41 4 12 90

1997 51 38 3 10 102

1998 23 19 10 8 60

1999 54 60 5 19 138
94

Figure 1. Map of Atlantic Ocean basin and localities for leatherback distribution.

-80-80

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#

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#

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N

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#

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95

Figure 2. Map of Caribbean Sea basin and localities for leatherback distribution.

N

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N

Northeast and M id-Atlantic Aerial

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September T ransects

Figure 3. Leatherback sightings and transect effort in aerial surveys of the Northeast U.S. and

Mid-Atlantic, 1994-1998. Some sightings may be obscured by others. Transect effort of

Shoop and Kenney (1992) is not included, while sightings are.
97

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Figure 4. Leatherback sightings and transect effort in aerial surveys of the Southeast U.S. and Gulf of Mexico, 
98

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Figure 4. (continued)

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99

Figure 5. Size distribution of leatherback strandings by region, 1986-19997.
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101

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extrapolated values.

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(Meylan et al. 1995, FWC 200026).

26 Unpublished data, Florida Fish and Wildlife Conservation Commission, statewide nesting beach survey program database.
103

Figure 9. Seasonal leatherback stranding totals by region, 1986-19997

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104

Figure 10. Statistical zones along the U.S. Atlantic and Gulf of Mexico coasts.
Part III

ASSESSMENT OF THE IMPACT OF

THE PELAGIC LONGLINE FISHERY

ON LOGGERHEAD AND

LEATHERBACK SEA TURTLES OF

THE NORTH ATLANTIC
106

Table of Contents

CHAPTER 1. DESCRIPTION OF THE ATLANTIC OCEAN AND MEDITERRANEAN SEA

PELAGIC LONGLINE FISHERIES.......................................................................................... 108

Literature Cited ....................................................................................................................... 111

CHAPTER 2. ANALYSIS OF MARINE TURTLE BYCATCH BY THE U.S. ATLANTIC

PELAGIC LONGLINE FLEET.................................................................................................. 120

Introduction............................................................................................................................. 120

Methods................................................................................................................................... 121

Data Sets.............................................................................................................................. 121

Catch Estimation................................................................................................................. 124

Delta lognormal bycatch estimation with pooling criterion Nmin=5 ............................... 124

Bycatch estimation by delta-GLM approach .................................................................. 127

Results And Discussion........................................................................................................... 129

Delta-lognormal bycatch estimates..................................................................................... 129

Bycatch Factors................................................................................................................... 130

Delta-GLM bycatch estimates............................................................................................. 134

Probability of a positive set............................................................................................. 134

Bycatch rate of positive sets............................................................................................ 135

Summary................................................................................................................................. 139

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

CHAPTER 3. SIZES OF SEA TURTLES INCIDENTALLY CAPTURED IN ATLANTIC

AND MEDITERRANEAN PELAGIC LONGLINE FISHERIES AND THEIR NATAL

ORIGINS..................................................................................................................................... 143

Sizes........................................................................................................................................ 143

Natal Origins........................................................................................................................... 144

Literature Cited ....................................................................................................................... 146

CHAPTER 4. REVIEW OF POST CAPTURE MORTALITY AND SELECTED MORTALITY

RATES........................................................................................................................................ 152

Summary Findings.................................................................................................................. 152

Serious Injury/Mortality Criteria ............................................................................................ 152

Reviewer Comments............................................................................................................... 153

Revised Criteria for Determining Injury for Sea Turtle-Longline Fishery Interactions ......... 154

Estimating Post-Interaction Sea Turtle Mortality................................................................... 154

Post-Hooking Studies: Hawaii........................................................................................... 155

Post-Hooking Studies: Eastern Atlantic.............................................................................. 156

Post-Hooking Studies: Mediterranean ................................................................................ 157

Entanglement....................................................................................................................... 158

Conclusions and Recommendations ....................................................................................... 159

Literature Cited ....................................................................................................................... 160

CHAPTER 5. SUMMARY OF TAKES BY THE PELAGIC LONGLINE FISHERY IN THE

ATLANTIC OCEAN AND MEDITERRANEAN SEA ............................................................ 161

Summary of Takes.................................................................................................................. 161

Impacts of the Pelagic Longline Fishery on Sea Turtle Populations ...................................... 163

CHAPTER 6. IMPACT OF THE PELAGIC LONGLINE FISHERY ON LOGGERHEAD SEA

TURTLES ................................................................................................................................... 170
107

Expanded TED Regulations.................................................................................................... 172

Changes in Pelagic Juvenile Annual Survival Rates .............................................................. 173

Combination of Expanded TED Regulations and Changes in Pelagic Juvenile Annual Survival

................................................................................................................................................. 174

Population Recovery............................................................................................................... 174

Literature Cited ....................................................................................................................... 174

CHAPTER 7. IMPACT OF THE PELAGIC LONGLINE FISHERY ON LEATHERBACK

SEA TURTLES........................................................................................................................... 201

Literature Cited ....................................................................................................................... 206

CHAPTER 8. EVALUATION OF POSSIBLE REASONABLE AND PRUDENT

ALTERNATIVES BEING CONSIDERED............................................................................... 207

Hook Styles............................................................................................................................. 207

Literature Cited ................................................................................................................... 209

Time-Area Closure.................................................................................................................. 210

Supplemental Bycatch Analysis to Determine Times and Areas of High Interactions ...... 210

Turtles Involved with Longline Gear in the Grand Banks.................................................. 213

Description of data sources............................................................................................. 213

Evaluation of the Effect of Sea SurfaceTemperature and Time of Set on Sea Turtle Bycatch

off the Northeast U.S............................................................................................................... 220

Sea Surface Temperature .................................................................................................... 220

 Time of Set......................................................................................................225
108

CHAPTER 1. DESCRIPTION OF THE ATLANTIC OCEAN AND

MEDITERRANEAN SEA PELAGIC LONGLINE FISHERIES

Wayne N. Witzell, Sheryan P. Epperly, and Lisa A. Csuzdi

The United States is one of at least 23 other countries that fished in the Atlantic Ocean

and Mediterranean Sea with pelagic longlines during 1990-1997 (Carocci and Majowski 1998).

The Atlantic pelagic longline fisheries typically consist of a free floating mainline that supports

multiple baited gangions. Pelagic longline vessels target sharks (Carcharinus spp.), swordfish

(Ziphias gladius), and various tunas (Thunnus spp.), particularly yellowfin, bigeye, and albacore,

depending on season and geographic location. The various swordfish fisheries in the Atlantic

Ocean and Mediterranean Sea have recently been described by Folsom (1997a,b, Folsom et al.

1997, Brewster-Geisz et al. 1997, Barrett et al. 1998, Weidner and Arocha 1999, Weidner et al.

1999a,b). The fisheries are extensive, diverse, and dynamic and are economically important. The

fishermen are able to change gear configurations and fishing strategies, depending on target

species, location, and time of year. Domestically, the U.S. pelagic longline fishery has been

described from a mandatory logbook system implemented and managed by the National Marine

Fisheries Service (NMFS), Southeast Fisheries Science Center (SEFSC) in Miami, Florida

(Cramer and Adams 2000). Additional information on the U.S. longline fleet is from the NMFS,

SEFSC pelagic observer program (Lee and Brown 1998). Hoey and Moore (19991) also provide

a summary description of the U.S. pelagic longline fishing gear, fishing strategy, and catch

composition using observer data and Witzell (1999) provided a description of distribution and

relative abundance sea turtle takes by the U.S. longline fleet using NMFS, SEFSC 1992-1995

logbook data.

 Most of the foreign high seas fisheries in the Atlantic Ocean are basically similar to

those of the United States, in that they fish multiple days and fish many miles of line per day.

However, the Mediterranean longline fisheries of Italy, Greece, and Malta, apparently fish

smaller vessels than the larger oceanic fleets. They set once per night, relatively close to shore,

and return to port between sets (Argano et al. 1992, De Metrio et al. 1983, Gramentz 1989,

Panou et al., 19912, 19923).

Most nations that fish pelagic longline gear in the North and South Atlantic Oceans, Gulf

of Mexico, Caribbean Sea, and Mediterranean Sea belong to the International Commission for

 

1 Hoey, J.J. and N. Moore. 1999. Captain’s report: multi-species catch characteristics for the U.S. Atlantic pelagic

longline fishery. MARFIN Grant – NA77FF0543 and SK Grant – NA86FD113 from National Marine Fisheries

Service, Silver Spring, MD to National Fisheries Institute, Inc., Arlington, VA., 78 pp.

2

Panou, A., S. Moschonas, L. Tselentis, and N. Voutsinas. 1991. Incidental catches of loggerhead turtles, Caretta

caretta, in swordfish long lines in the Ionian Sea, Greece. Unpublished Report. Institute of Zoology University of

Munich, Federated Republic of Germany, Munich, 6 pp.

3

Panou, A., G. Antypas, Y. Giannopoulos, S. Moschonas, D. Mourelatos, G. Mourelatos, Ch. Mourelatos, P.

Toumazatos, L. Tselentis, N. Voutsinas, and V. Voutsinas. 1992. Incidental catches of loggerhead turtles, Caretta

caretta, in swordfish long lines in the Ionian Sea, Greece. Unpublished Report. Institute of Zoology University of

Munich, Federated Republic of Germany, Munich, 8 pp.
109

the Conservation of Atlantic Tunas (ICCAT). This is the international research and management

organization that manages the tuna and billfish species affected by longlines in the Atlantic

Ocean. Fisheries data such as yield (landings), catch per unit effort (CPUE), individual sizes and

weights are collected by ICCAT countries and used in stock assessments and for regulatory

considerations. There are many countries that fish pelagic longlines in the Atlantic and

Mediterranean Sea, and other countries may move from one geographic area to another,

changing target species depending on fishing success and ICCAT regulations. Some fishing

vessels operate under another nation’s flag or otherwise do not report landings under any

particular country. These landings are designated NEI (Not Elsewhere Included).

The reported longline yields of swordfish and tunas were tabulated from the ICCAT data

base (CATDIS, found at www.iccat.org or www.iccat.es under the Statistics and Monitoring

Section). These data are sent to the United Nations Food and Agricultural Organization (FAO)

for inclusion in the Atlas of Tuna and Billfish Catches (Carocci and Majkowski 1998). The

CATDIS data were summarized by region, year (1990-1997) and species group (tunas and

swordfish) for the U.S. and for all other nations combined. Regions were defined as

Mediterranean Sea, North Atlantic (data coded north of 9° N) and tropics (data coded as 10°

south of the equator to 9° north of the equator). Note that data are coded for 1° square cells and

are labeled with the degree latitude of its southern boundary. Thus, data coded as 9°N represents

yield attributed to fishing between 9° and 10°N. Consequently, although we refer to the Tropics

as 10°S to 9°N, that represents fishing between 10°S and 10°N. Similarly the North Atlantic,

labeled as >9°N, represent fishing at and north of 10°N.

Swordfish and tuna landings were summarized by nation for the years 1990-1997

combined (Figures 1-3). Countries with relatively little yield were eliminated for graphics clarity.

However, these countries will be listed in descending order of yield value. The United States

pelagic longline fleet is a major producer of swordfish and tuna in the north Atlantic. The U.S.

fleet is of less importance in the tropics, and is not a component of the Mediterranean Sea

fishery.

North Atlantic (Fig. 1):

The top three countries landing swordfish were Spain, United States, and Canada, and the

top producers of tunas were Japan, Taipei, and United States. The following countries landed

less than 1,800 mt of swordfish: Taipei, Brazil, NEI, Trinidad, Morocco, Cyprus, Venezuela,

Korea, Mexico, Cuba, United Kingdom, Bermuda, Peoples Republic of China, and Grenada. The

following countries landed less than 1,800 mt of tunas: Canada, Belize, Grenada, Brazil, Peoples

Republic of China, Cuba, France, and Ireland.

Tropics (Fig. 2):

The top producers of swordfish were Spain, Japan, and Taipei, and the top producers of

tunas were Japan, Taipei, and Honduras. The following countries landed less than 2,500 mt of

swordfish: Brazil, United States, Korea, Portugal, Cuba, Peoples Republic of China, and

Equatorial Guinea. The countries that landed less than 2,500 mt of tunas were Spain, Libya,

United States, Cuba, Venezuela, Peoples Republic of China, USSR, Portugal, and Equatorial

Guinea.
110

Mediterranean Sea (Fig. 3):

The top producers of swordfish were Italy, Greece, and Morocco, and the top producers of tunas

were Italy, NEI (Not Elsewhere Included), and Spain. Those countries reporting less than 500 mt

for swordfish were Malta and Japan, and those countries reporting less than 500 mt of tunas were

NEI, Cyprus, Peoples Republic of China, Croatia, and Taipei.

The U.S. portions of the total catches are shown in Figures 4 and 5. It is unclear how well

yields of one target species will reflect the relative efficiency of a fleet at catching other species,

e.g. sea turtles. To examine the indications of U.S. fishing efficiency relative to swordfish and

tunas, sample CPUE data from ICCAT were examined for 1990-1996. Catch in that data set

were primarily recorded in number of fish. The sampled CPUE data (Figures 6-9) indicates that

the U.S. accounted for less than 10% (5%-8%) of the sampled hooks fished in the North Atlantic

Ocean. If total numbers of hooks (effort) data were available for all nations, it is expected that

the U.S. proportion would be lower. This is because a large fraction of the total U.S. pelagic

longline effort is included in the sample, while other nations do not report sampled effort and, of

those nations that do report samples, it is not known what fraction of fishing effort is actually

reported.

In the North Atlantic, the U.S. fleet was roughly 4-8 times more efficient (proportion

catch/proportion hooks) than the other fleets at catching swordfish and about 2-3 times more

efficient at catching tunas (Figure 6). There was less information on U.S. fishing in the Tropics

(Figure 8) because of less effort, but the calculated efficiencies were generally lower for

swordfish (from equally efficient to 12 times more efficient with all but 2 years at roughly equal

efficiency to 3 times more efficient.), and lower for tunas (about 1.5-2 as efficient). Examination

of a subsection of the North Atlantic (Caribbean) revealed markedly different efficiencies. The

U.S. fleet was about 3-5 times more efficient at catching swordfish, but less efficient than other

sampled fleets at catching tunas (from about 0.1 to about 0.3 times as efficient). In summary, it

appears that:

1. The U.S. longline fleet accounts for a relatively small proportion of total hooks fished in the

Atlantic Ocean.

2. The relative fishing efficiency of the U.S. fleet at catching swordfish and tunas varies

spatially, and probably temporally.

3. There likely are differences that occur in fishing efficiencies at catching non-target species

(including sea turtles) between fleets both temporally and spatially.
111

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marine comune (Caretta caretta) in Mediterraneo. Bollettino Musel Istitiuti Universita

Genova 56-57:137-163.

Barret, I., O. Soas-Nishizaki, and N. Bartoo, eds. 1998. Biology and fisheries of swordfish,

Ziphias gladius. U.S. Department of Commerce NOAA Technical Report NMFS-142, 276 pp.

Brewster-Geisz, K., D.M. Crory, and W.B. Folsom. 1997. World swordfish fisheries. An

analysis of swordfish fisheries, market trends, and trade patterns. Past-Present-Future. Vol.

V, North America. NOAA Technical Memorandum NMFS-F/SPO-28, 136 pp.

Carocci, F. and J. Majkowski. 1998. Atlas of tuna and billfish catches. CD-ROM version 1.0.

FAO, Rome, Italy.

Cramer, J. and H. Adams. 2000. Large pelagic logbook newsletter – 1998. U.S. Department of

Commerce NOAA Technical Memorandum NMFS-SEFSC-433, 25 pp.

De Metrio, G., G. Petrosino, A. Matarrese, A. Tursi, and C. Montanaro. 1983. Importance of

fishery activities with drift lines on the populations of Caretta caretta (L.) and Dermochelys

coriacea (L.) (Reptilia, Testudines), in the Gulf of Taranto. Oebalia 1983, Vol. IX (N.S.):43-

53.

Folsom, W.B. 1997a. World swordfish fisheries, market trends, and trade patterns. Past-PresentFuture. Vol. II, Africa and the Middle East. U.S. Department of Commerce NOAA

Technical Memorandum NMFS-F/SPO-24, 235 pp.

Folsom, W.B. 1997b. World swordfish fisheries. An analysis of swordfish fisheries, market

trends, and trade patterns. Past-Present-Future. Vol. VI, Western Europe. U.S. Department

of Commerce NOAA Technical Memorandum NMFS-F/SPO-29, 324 pp.

Folsom, W.B., D.M. Weidner, and M.R. Wildman. 1997. World swordfish fisheries. An analysis

of swordfish fisheries, market trends, and trade patterns. Past-Present-Future. Vol. I.

Executive Overview. U.S. Department of Commerce NOAA Technical Memorandum

NMFS-F/SPO-23, 53 pp.

Gramentz, D. 1989. Marine turtles in the central Mediterranean Sea. Centro 1(4): 41-56.

Lee, D.W. and C. Brown. 1998. SEFSC pelagic observer program data summary for 1992-1996.

U.S. Department of Commerce NOAA Technical Memorandum NMFS-SEFSC-408, 21 pp.

Weidner, D.M. and F. Arocha. 1999. World swordfish fisheries. An analysis of swordfish

fisheries, market trends, and trade patterns. Past-Present-Future. Vol. IV, Latin America.

Part A, South America. Section 2, Atlantic. Segment B, Brazil. U.S. Department of

Commerce NOAA Technical Memorandum NMFS-F/SPO-35:237-628.
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Weidner, D.M., F.J Fontes, and J.A. Serrano. 1999a. World swordfish fisheries. An analysis of

swordfish fisheries, market trends, and trade patterns. Past-Present-Future. Vol. IV, Latin

America. Part A, South America. Section 2, Atlantic. Segment C, Uruguay, Paraguay. U.S.

Department of Commerce NOAA Technical Memorandum NMFS-F/SPO-36:631-916.

Weidner, D.M., F. Arocha, F.J. Fontes, W.J. Folsom, J.A. Serrano, and D.R. Starks. 1999b.

World swordfish fisheries. An analysis of swordfish fisheries, market trends, and trade

patterns. Past- Present- Future. Vol. IV, Latin America. Part A, South America. Sec. 2,

Atlantic. Segment A, Venezuela, Guyana, Suriname, and French Guiana. U.S. Department

of Commerce NOAA Technical Memorandum NMFS-F/SPO-34, 235 pp.

Witzell, W.N. 1999. Distribution and relative abundance of sea turtles caught incidentally by the

U.S. pelagic longline fleet in the western North Atlantic Ocean, 1992-1995. Fishery Bulletin

97:200-211.
113

Figure 1. Yield of swordfish and tunas from the North Atlantic Ocean (Data from Carocci and

Majkowski 1998).

Nations with yields <1800 MT were not included in this graph. Listed in descending order for swordfish these

include Taipei, Brazil, NEI, Trinidad, Morocco, Cyprus, Venezuela, Korea, Mexico, Cuba, UK, Bermuda, Peoples

Republic of China, and Grenada. For tunas these include Canada, Belize, Grenada, Brazil, Peoples Republic of

China, Cuba, France, and Ireland.
114

Figure 2. Yield of swordfish and tunas from the Tropical Atlantic Ocean (Data from Carocci and

Majkowski 1998).

Nations with yields < 2500 MT were not included in this graph. Listed in descending order for swordfish these

include Brazil, U.S.A, Korea, Portugal, Cuba, Peoples Republic of China, and Equatorial Guinea. For tunas these

include Spain, Libya, U.S.A, Cuba, Venezuela, Peoples Republic of China, USSR, Portugal, and Equatorial Guinea.
115

Figure 3. Yield of swordfish and tunas from the Mediterranean Sea (Data from Carocci and

Majkowski 1998).

Nations with yields < 500 MT were not included in this graph. Listed in descending order for swordfish these

include Malta and Japan. For tunas these include NEI, Cyprus, Peoples Republic of China, Croatia, and Taipei.
116

Figure 4. Proportion of the total yield of swordfish and tunas taken from the North

Atlantic by the U.S. pelagic longline fleet.

N Atlantic (>9N)

0

0.2

0.4

0.6

0.8

1

19901991199219931994199519961997

year

US proportion of yield

sword

tunas
117

Figure 5. Proportion of the total yield of swordfish and tunas taken from the Tropical

Atlantic by the U.S. pelagic longline fleet.

 Figure 6. Proportion of total hooks, swordfish and tunas (in numbers of fish) in ICCAT

catch/effort samples from the North Atlantic accounted for by the U.S. pelagic longline

fleet.

tropics (10S-9N)

0

0.2

0.4

0.6

0.8

1

19901991199219931994199519961997

year

US proportion of yield

sword

tunas

Sample Catch-Effort Data

N Atlantic > 9N

0.00

0.10

0.20

0.30

0.40

0.50

1990 1991 1992 1993 1994 1995 1996

year

US / total

hooks

swordfish

tunas
118

Figure 7. Numbers of hooks, swordfish and tunas, from ICCAT catch/effort samples from

pelagic longliners in the North Atlantic.

Figure 8. Proportion of total hooks, swordfish and tunas, (in number of fish) in ICCAT

catch/effort samples from the Tropical Atlantic accounted for by the U.S. pelagic

longline fleet.

Sample Catch-Effort Data

N Atlantic > 9N

0

200,000

400,000

600,000

800,000

1,000,000

1990199119921993199419951996

year

n fish

0

50,000,000

100,000,000

150,000,000

200,000,000

hooks

swordfish tunas hooks

Sample Catch-Effort Data

tropics (10S-9N)

0.00

0.01

0.02

0.03

0.04

0.05

1990 1991 1992 1993 1994 1995 1996

year

US / total

hooks

swordfish

tunas
119

Figure 9. Numbers of hooks, swordfish and tunas, recorded in ICCAT catch/effort

samples from pelagic longliners in the Tropical Atlantic.

Sample Catch-Effort Data

tropics (10S-9N)

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1990199119921993199419951996

year

n fish

0

50,000,000

100,000,000

150,000,000

200,000,000

hooks

swordfish tunas hooks
120

CHAPTER 2. ANALYSIS OF MARINE TURTLE BYCATCH BY THE U.S.

ATLANTIC PELAGIC LONGLINE FLEET

Cynthia Yeung

Introduction

The U.S. pelagic longline fleet targeting tuna (Thunnus spp.) and swordfish (Xiphias

gladius) in the North Atlantic (including the Caribbean Sea and the Gulf of Mexico) occasionally

interacts with marine turtles (Berkeley et al. 1981; Hoey and Bertolino 1988). Turtles are hooked

or entangled, resulting inevitably in injury or in extreme cases, death. In this paper, the bycatch

of marine turtle by the said fleet in 1992-1999 is estimated and factors that influenced bycatch

rates are examined.

The bycatch of marine turtles by the U.S. pelagic longline fishery in 1992-1997 and 1998

has been estimated previously using the delta-lognormal method (Pennington 1983). The

bycatch estimates were based on a random sample of the longline fishing vessels on which

trained observers were placed. Due to the random nature of the sampling and relatively low

sampling fractions, not all time-area strata have been observed. Thus, pooling observations

between strata is necessary to estimate fleet-wide bycatch. In several previous reports (Johnson

et al. 1999; Yeung 1999a,b), the robustness of the bycatch estimates from several different

pooling schemes for bycatch rates were examined, from the lowest level of pooling (stratified

estimates by year-quarter-grouped fishing area (NAREA)) to the highest level of pooling

(stratified estimates by year-large fishing region (MAREA), where MAREA is the result of

pooling NAREA). For those analyses, however, no estimates were made for strata that remained

without observed effort after pooling, even though there was unobserved effort reported by the

fishing fleet.

Here, the delta-lognormal method is again used to obtain estimates of the mean and variance

of longline turtle bycatch for 1992-1999, but a criterion of a minimum number of observed sets

(Nmin) is used to determine the level of pooling from which to estimate bycatch rates for a timearea stratum. By this approach, estimates are made for all strata. This method was applied

effectively to the estimation of tuna and swordfish catches by the U.S. Atlantic pelagic longline

fleet (Brown, in press). A preliminary report on the estimated bycatch of marine turtles and

mammals based on this method has been prepared earlier (Yeung et al. 20004). According to this

pooling method, the levels of 1) quarter, 2) year and 3) NAREA are successively pooled in that

order until the criterion is met. The order of pooling followed the increasing order of

significance of these three factors in an ANOVA model on bycatch rate. With this dynamic

pooling method, if observer effort is adequate according to Nmin in a basic year-quarter-NAREA

 

4 Yeung, C., S. Epperly, and C. A. Brown. 2000. Preliminary revised estimates of marine mammal and marine turtle

bycatch by the U.S. Atlantic pelagic longline fleet, 1992-1999 National Marine Fisheries Service Miami Laboratory

PRD Contribution Number 99/00-13, SEFSC Miami, Fla. Revised tables with estimates through 1999 are in

Appendix 3 and data on turtles observed in 1999 and 2000 are in Appendix 3 and turtles and observers comments

are detailed in Appendix 4.
121

stratum, then an estimate is obtained based on the observed bycatch rate of the stratum and the

data independence of the basic stratum is maintained; otherwise, bycatch rate will be

extrapolated from some other strata that ideally should have similar characteristics. The main

objective is to avoid leaving empty cells with no estimates available. Results from this deltalognormal-Nmin method are compared with an alternative estimation method using generalized

linear modeling (GLM) with the delta approach (Stefánsson 1996). GLM and regression trees

methods are also used to shed light on the factors that influence the bycatch rates of marine

turtles.

Methods

Data Sets

Systematic sampling by scientific observers on board U.S. pelagic longline vessels in the

Atlantic permitted to land and sell swordfish was implemented in 1992, under the mandate of the

1991 amendments to the U.S. Fishery Management Plan (FMP) for Atlantic Swordfish. The

estimated bycatch rates of marine turtles in the pelagic longline fishery are based on observer

sampling data collected and maintained by the NMFS Southeast Fisheries Science Center

(SEFSC) (Lee and Brown 1998).

The Atlantic Large Pelagic Logbook database, also maintained by the SEFSC, contains

daily fishing effort reported by all U.S. Atlantic longline vessels landing swordfish and tuna as

required under the Atlantic Swordfish Fishery Management Plan since 1986 (Cramer and Adams

2000). Not withstanding errors due to misreporting, fishery-reported effort from the logbook

(reported effort) is taken to represent the actual permitted effort expended by the U.S. pelagic

longline fleet in the North Atlantic.

Observed bycatch rates are raised to the amount of reported effort in the logbook for

estimating total bycatch. The unit of effort is an individual set (gear deployment) that fished at

least 100 hooks and included tunas and/or swordfish among the declared target species –

application of this criterion results in reported effort about 10% higher compared to effort

reported to target only tunas and/or swordfish. Effort is grouped by fishing area, the smallest area

grouping is AREA (Fig. 1). The eleven AREAs are further grouped into six NAREAs, which are

the areal strata used here for bycatch analysis. Effort missing location data are proportionally

distributed among AREAs based on the distribution of known set locations for the pertinent year

and calendar quarter. Effort missing calendar quarter data within a fishing area are

proportionally distributed among quarters based on the distribution of effort across quarters

within the area. Only aabout 1% of the effort data are missing time and/or area information.

Apart from systematic revisions to the data sets since the previous reports that may have led

to changes, the effort data are treated slightly differently compared to previous reports. The

fishing location was previously defined by where the longline was set to begin fishing, but here

is defined by the location where the haul-back of the longline began after fishing. Also, the parts

of a set that were interrupted (e.g., when the main line was severed) previously were defined as

separate sets, but now are combined as a single set.
122

In addition to the essential time-area information on the fishing set, gear and effort

information are also recorded on observed trips. Some gear and effort characteristics are

potentially influential on bycatch of marine turtles (Kleiber 20005). A subset of these gear-effort

variables (Table 1) is selected for exploratory analysis, including GLM and regression tree

analysis conducted with the S-PLUS software (MathSoft 1997), to identify significant factors

that may be incorporated into models for predicting bycatch rates.

Figure 1. The eleven geographical areas (AREA) used to classify U.S. Atlantic pelagic longline

fishing effort. AREAs are further arranged into 6 grouped strata (NAREA): 1) Southeast Coastal

(SEC) = AREAs 3 and 4; 2) Northeast Coastal (NEC) = AREAs 5 and 6; 3) the Offshore South

(OFS) = AREAs 8, 9, 10, and 11. Each one of the AREAs: 4) Caribbean (CAR), 5) Gulf of

Mexico (GOM), and 6) Northeast Distant (NED), is also a distinct NAREA.

 

5 Kleiber, P. 2000. Working group on reducing turtle bycatch in longline fisheries. Report of First Meeting.

September 12 –13, Los Angeles, U.S.A. Unpublished report. National Marine Fisheries Service, SWFSC,

Honolulu, Hawaii, 11 pp.

-95 -90 -85 -80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20

5

10

15

20

25

30

35

40

45

50

55

 1

CAR

 2

GOM

 3

SEC

 4

SEC 

 5

NEC

 6

NEC

 7

NED

 9

OFS

 8

OFS

 10

OFS

 11

OFS

 5

13

35

65 60

 |

71

 |

78

 |

82

 |

22--

1 Caribbean

2 Gulf of Mexico

3 Florida East Coast

4 South Atlantic Bight

5 Mid Atlantic Bight

6 Northeast Coastal

7 Northeast Distant

8 Sargasso

9 North Central Atlantic

10 Tuna North

11 Tuna South
123

Table 1. Time-area and gear-effort variables considered for predictors in the GLM approach.

Strikeover variables are omitted from consideration because of any combination of the following

reasons: 1) insufficient data, 2) collinearity with other selected variables, 3) insignificant effect

on the catch rate in exploratory analysis.

Variable type: E=effort G=gear C=catch c=categorical q=quantitative

VARIABLE DESCRIPTION

set

Cc year

Cc area

Cc month

target catch

Cq srkn number of shark caught

Cq swfn number of swordfish caught

Cq tunn number of tuna caught

longline length

Eq MAINLEN mainline length (nm)

Eq HOOKSET number of hooks set

Eq SOAKDUR soak duration (hrs)

Eq FLOATNUM number of floats used

Eq LITENUM number of light sticks used

Eq RATLRNUM number of rattlers used

Eq SRFLTNUM number of surface lights used

Gq HKSBFLT max hooks between floats

Gq GANGDIS gangion distance

Gq GANGCNT gangion count

longline depth

Gq GANGLEN gangion length (ft)

Gq LEADLEN leader length (in)

Eq HKDEPMIN max hook depth (fm)

Eq HKDEPMAX min hook depth (fm)

bait

Eq BAITNUM

Ec BAITKND 01-Mackerel, 02-Herring, 03-Squid, 04-Artificial, 05-Sardine, 06-Scad, 99-Other

Ec BAITTYP 1-Whole, 2-Cut, 3-Live, 9-Other

Ec BAITCON 1-Frozen, 2-Semi-frozen, 3-Thawed, 4-Fresh, 5-Salted, 9-Other

temperature

Eq TEMP mean of begin/end set/haul temp (F)

hook

Gc HKBRAND hook brand

Gc HKPATRN hook pattern

Gc HKSIZE hook size

auxiliaries

Gc LITECOLR light stick color

Gc GANGCOLR gangion color

Gc LEAD leader used?

Ec LITESTX light sticks used? 1=yes, 2=no

Ec SRFLITE surface lights used?

Ec RATLR rattlers used?
124

Catch Estimation

Delta lognormal bycatch estimation with pooling criterion Nmin=5

The delta-distribution or delta-lognormal method (Pennington 1983) provides minimum

variance unbiased (MVU) estimators of means and variances for sampling data that contain

many zero observations and the non-zero observations are lognormally distributed. The sample

mean as an estimator in that case may overestimate the population mean, and the variance of the

sample mean can be very large. The robustness of the delta-lognormal estimators depends on the

assumption of lognormal distribution of the non-zero (positive) observations (Myers and Pepin

1990; Syrjala 2000).

The delta-lognormal method is a possible approach for estimating the observed bycatch

rates of turtles. The observation unit is a longline fishing set, and the observed response is the

bycatch rate = number caught per 1000 hooks (cph). A quantile-quantile plot of the distribution

function of the ln-transformed positive bycatch rates (lcph:{lcph>0}) for all species and the

normal distribution shows departures from linearity at the tail ends that is not unexpected of

small to moderate sample sizes (Fig. 2a), and it appears unlikely that any other parametric

distribution will fit the sample data substantially better (Fig. 2b). The lognormal distribution

may thus be an “acceptable” approximation for all practical purposes. The same trends apply

whether for all species combined (n=429), loggerheads (n=198), or leatherbacks (n=201). The

rare turtle species in the bycatch - green, hawksbill, and Kemp’s Ridley, cannot be tested

separately because of the extremely low sample sizes (total n=30).

a b

Figure 2. a) Quantile-quantile plot of the distribution function of observed ln-transformed

positive bycatch rates {lcph>0} for all species and the normal distribution; b) frequency

comparison of the same observed data and the fitted distribution.

-3 -2 -1 0 1 2 3

Normal Distribution

0.7

1.2

1.7

2.2

2.7

lcph

Variable: lcph ; distribution: Normal

Category (upper limits)

No of obs

0

20

40

60

80

100

120

140

160

180

200

0.400 0.771 1.143 1.514 1.886 2.257 2.629 3.000

Expected

all species (n=429)
125

The bycatch estimates are constructed as a product of the proportion of positive sets and

the average bycatch rate of the positive sets (Pennington 1983). Estimated bycatch for a basic

time-area stratum (year-quarter-NAREA), C, is estimated as:

),

2

(

2

L

m

c L

s

e G

N

m

C = H c(1)

H = reported number of hooks set, divided by 1000,

mc= number of sets in which a non-zero bycatch was observed (positive sets),

N = total number of sets observed,

L = ∑Li mc,

1

( )

2

2

−

−

=

∑

c

i

L

m

L L

s , where

Li = ln(bycatchi/hooksi ×1000) = lcphi, ln-transformed bycatch rate for the i

th positive set,

i=1,...,mc,

 L = mean of Li,

 sL

2

 = sample variance of Li;

and the function )

2

(

2

L

mc

s

G is:

.

!

)

2

(

( 1)( 3)...( 2 3)

( 1)

)

2

(

1

) 1

2

(

2

2

2 2 2 1

∑

∞

=

−

×

+ + + −

−

+

−

= +

j

L j

c c c

j

c

j

L c

c

L c

mc

j

s

m m m m j

s m

m

s m

G (2)

Numerically, the series is computed over j terms, until a convergence criterion of <0.001 change

in the function is achieved (usually less than 10 terms are required). The estimate of variance of

the bycatch takes the form:

s )].

m

m

)G (

N

m

) (

s

G (

N

m

(He ) [

N

m

V(C) L

c

c

m

L c

m

c L c

c c

2

2

2 2

1

2

1

1

2 −

−

−

−

= − (3)

Bycatch estimates by stratum are assumed independent, and the proportion of positive

sets (mc/N) and reported number of hooks (H) are treated as constants within a stratum and thus

uncorrelated with the bycatch rate. The coefficient of variation for the stratum-wise estimate of

bycatch is:

.

C

V(C) CV = (4)

In the previous reports (Johnson et al. 1999; Yeung 1999a; 1999b), when there was no

observer effort (= fishing set) for a particular analytical stratum, i.e., N=0, the mean bycatch rate

L and the proportion of positive sets, mc/N were not estimated. Thus, no estimate of bycatch was

made for the stratum even though there was reported fishing effort (H>0) in the logbook.

Quarters lacking observed effort occurred mainly in the NAREAs of CAR, NED, and OFS, all

relatively far from the continental U.S. coast (Fig. 1) and where U.S. pelagic longline fishing

effort is typically low (Fig. 3). When observed effort is pooled across quarters within a NAREAyear stratum, cells lacking observed effort only occur in OFS in 1992, and NED in 1996 and

1998 (Fig. 3).
126

Figure 3. Quarterly a) reported sets and b) observed sets by NAREA, 1992-1999.

Pooling allows extrapolation of bycatch rate to a basic time-area stratum that has no

observed effort using data from related strata. A possible disadvantage of pooling is that it may

smooth out the inherent heterogeneities among time-area strata and distort bycatch patterns and

trends. Pooling is therefore applied only when necessary by assessing whether a criterion of a

minimum number of observed sets (Nmin) is met for a basic stratum. To determine the order of

factors to pool, the effect of year, quarter, and NAREA on the bycatch rate was evaluated with

the ANOVA model

Lj = year + quarter + NAREA,

where Lj = ln(bycatchj/hooksj + 1), j = 1, 2,..., N is the bycatch rate (including zeros) in the j

th

observed set. The model was assessed for 1) all turtle species combined, 2) leatherbacks, and 3)

loggerheads. In each case, NAREA is responsible for the greatest model effect, followed by year

and then quarter (Table 2). The standard pooling priority order of quarter, year, and NAREA is

established according to the increasing order of variance explained attributed to the effect, i.e.

pooling similar levels first. Next, a low Nmin of 5 sets and a high of 30 sets observed are

arbitrarily chosen to be tested, emulating what have been used in bluefin tuna assessment

(Brown, in press). Both produced bycatch estimates of similar magnitudes, which indicates both

criteria resulted in similar amount of pooling (Yeung et al. 20004). The criterion of Nmin = 5 was

chosen to potentially minimize the necessity to pool in most cases. The stepwise pooling

procedure is thus: in the absence of observer data for a stratum, data are first pooled across

quarters to obtain a minimum sample size of 5 observed sets. Should the pooling across quarters

not suffice to achieve the Nmin, data are then pooled across years, and if still failing the criterion,

data are lastly pooled across NAREAs to obtain an estimate of L and mc/N, for the stratum. The

variance for the bycatch V(C) is then estimated over the pooled stratum.

a. Reported effort

OFS

92 93 94 95 96 97 98 99 00

0

500

1000

1500

2000

b. Observed effort

SEC

NED

0

25

50

75

100

GOM

92 93 94 95 96 97 98 99 00

OFS

92 93 94 95 96 97 98 99 00

0

25

50

75

100

SEC

NEC

sets

CAR

0

500

1000

1500

2000

NED

0

500

1000

1500

2000

GOM

92 93 94 95 96 97 98 99 00

NEC

CAR

0

25

50

75

100
127

Table 2. ANOVA of time-area effects on ln-transformed bycatch rate (lcph) of marine turtles

Model: lcph = year + NAREA + quarter

 *** Analysis of Variance Model ***

 Type III Sum of Squares

1) All species

 Df Sum of Sq Mean Sq F Value Pr(F)

 yr 7 6.4282 0.91831 9.1049 0.00000000

 narea 5 68.8221 13.76443 136.4712 0.00000000

 quartr 3 1.0619 0.35396 3.5094 0.01465468

Residuals 4016 405.0520 0.10086

2) Leatherback

 yr 7 0.9559 0.136559 2.67591 0.00918291

 narea 5 7.7804 1.556083 30.49174 0.00000000

 quartr 3 0.4050 0.135015 2.64565 0.04747834

Residuals 4016 204.9482 0.051033

3) Loggerhead

 yr 7 5.3014 0.757339 12.78133 0.00000000

 narea 5 28.8476 5.769524 97.37008 0.00000000

 quartr 3 0.4804 0.160132 2.70249 0.04398371

Residuals 4016 237.9623 0.059254

Bycatch estimation by delta-GLM approach

There is concern that delta-lognormal estimators are not robust to seemingly small

departures of the distribution of the positive observations from lognormal, in which case the

delta-lognormal estimators may be positively-biased (Syrjala 2000). For comparison, an

alternative method of estimating bycatch is used that combines the delta approach with GLMs to

predict bycatch rate from predictor variables. Stefánsson (1996) described this maximum

likelihood estimation method that calls for the fitting of a GLM to 0/1 binary observations, and

another GLM to the positive observations.

Two models are fitted with the observed bycatch and effort data. The probability of a

positive set is modeled as a random response variable, bcatch, (= 1 if lcph>0, = 0 if lcph=0)

using a binomial model with a logit link function. The fitted response is the expected probability

of a positive set Pr(bcatch=1) = p. A separate GLM relates the expected bycatch rate of positive

sets (lcph>0) to the linear predictor by the gamma distribution and a log link function. The

gamma distribution fit to the positive bycatch rates (Fig. 4) is similar to lognormal fit (Fig. 2),

and models with gamma-log and gaussian-identity link functions produced similar results. The

gamma distribution has been suggested to be preferable in fisheries data in some cases where

there is a considerable probability of small observations, though the gain may be minor

(Stefánsson 1996). It is used here mainly as a comparison with the delta-lognormal distribution.

Analysis of deviance is used to evaluate significant predictor variables and select the final

models.
128

Figure 4. Frequency comparison of the observed ln-transformed positive bycatch rate {lcph>0}

of all turtle species and the fitted gamma distribution (parameters: a−shape; b-scale).

The fitted loge-transformed bycatch rate lcph from the gamma model is back-transformed

by cph = exp(lcph)-1,

where cph = bycatch per 1000 hooks = m, the expected bycatch rate for positive sets. The

estimated overall catch rate at a time-area stratum, Xˆ

, is then

Xˆ = pm, (5)

where p = expected probability of a positive set from the binomial model. The variance of the

estimated overall catch rate is calculated as

V( Xˆ) = ps

2

+m

2

p(1-p) = m

2

[p(1+1/a)-p

2

], (6)

where a = shape parameter and s

2 

= m

2

/ a = variance of the estimated gamma function

(Stefánsson 1996). The coefficient of variation of the estimate is

CV=

X

V X

ˆ

)

ˆ

(

Finally, the total estimated bycatch per stratum, Cg

ˆ

, is calculated as

Cg

ˆ = Xˆ × H,

where H = total reported number of hooks set for the stratum, divided by 1000, as defined in eq.

(1) (the subscript g distinguishes the delta-GLM model bycatch estimate from the deltalognormal catch estimate).

There are no prior assumptions of homogeneity in the structure of zero or non-zero

observations in this estimation approach, but a parametric function has to be assumed

nonetheless to link the mean and variance of the predicted response to the linear predictor, and

thus like the delta-lognormal method it is not distribution-free. In this method, missing cell

Turtle lcph (>0); distribution: Gamma

α=9.41; β=8.8

7

Category (upper limits)

No of obs

0

20

40

60

80

100

120

140

160

180

200

220

0.400 0.725 1.050 1.375 1.700 2.025 2.350 2.675 3.000

Expected
129

values are estimated based on factor level averages, an alternative to the pooling used in the

delta-lognormal method. The GLM approach can serve to evaluate the effect of different factors

on the bycatch rate and incorporate multiple significant factors to model bycatch rate. However,

the fit of GLMs can be hampered by unbalanced data structure and missing cells. It may not a

superior method to delta-lognormal for sparse data as in this case, but an alternative. Maximum

likelihood estimations for GLMs in this analysis are made with available routines in the S-PLUS

software (MathSoft 1997).

Results And Discussion

Delta-lognormal bycatch estimates

Reported nominal effort (number of fishing sets) in 1992-1999 shows that fishing effort

and trends varied among NAREAs (Fig. 3a). Intra-annually, effort in the northern NAREAs of

NEC and NED peaked in the 3rd quarter, and was lowest in the 1st quarter. The reverse annual

trend is apparent in the southern NAREAs of OFS and CAR, where effort peaked in the 1

st

quarter and was lowest in the 3rd quarter. SEC had peak effort in the 2nd quarter, whereas effort

in GOM was distributed relatively evenly among quarters. Average effort was highest in GOM,

NEC, and SEC in the coastal zone of continental U.S. With the exception of GOM, annual

nominal effort was somewhat lower in other NAREAs in recent years. For the coastal NAREAs

of GOM, NEC, and SEC, annual observed effort was ≤5% of reported effort, and the quarterly

distribution of observed effort approximated the reported trend. The distant NAREAs of CAR,

NED, and OFS received more sporadic observer coverage and often none at all (Fig. 3b).

Between 1992-1999, 4032 longline sets were observed, of which 429 (~11%) caught

turtles. Most of the turtles caught in the longline were either loggerheads or leatherbacks (Table

3). It is likely that the green, hawksbill, and Kemp's Ridley takes were mis-identifications, and

were in fact loggerheads, the most common hard-shelled turtle taken in the fishery (Hoey 1998;

Witzell 1999). Of the turtles caught, rarely were any observed to be dead (Table 3), but this does

not discount the possibility that those observed to be released alive might have sustained serious

or fatal injuries. The results of expanding observed bycatch rates estimated by the deltalognormal method to the level of reported effort show that estimated mean bycatch (CV ≤ 1) of

loggerheads and leatherbacks were highest in NED and NEC (Fig. 5), and peaked generally in

the 3rd quarter in accordance with the quarterly trend in fishing effort. An estimated 100-200

leatherbacks were caught in the peak quarter in the NEC and NED (Fig. 5a). Exceptionally high

estimated bycatch of leatherbacks occurred in NEC 1992 (265, CV=0.28), NED 1995 (580, 0.17)

and NED 1999 (384, 0.31).

Estimated mean bycatch of loggerheads were generally higher in NED than NEC (Fig.

5b). High bycatch years in NEC were 1995, 1998, and 1999 with 200-300 loggerheads estimated

caught in the 3rd quarter. For NED, estimated mean bycatch of loggerheads exceeded 300 in the

3

rd quarter of 1994-1996, and 1998-1999 - extreme highs occurred in 1994 (1001, 0.17) and 1995

(1413, 0.2). Note that in 1996 and 1998 there was no observed effort in NED (Fig. 3), therefore

the bycatch estimates were based on pooled bycatch rates for all the other years combined.

Considering that the reported effort in NED was a factor of 3-4 lower than in NEC, the

comparable bycatch estimates between the two areas distinguish NED as the area of highest

catch rates of leatherbacks and loggerheads.
130

Table 3. Numbers and species of marine turtles caught in longline sets observed between 1992-

1999. The number observed as dead is a subset of the total number caught.

species caught dead sets

loggerhead 355 4 198

leatherback 263 1 201

green 15 2 11

hawksbill 3 0 3

Kemp's

Ridley 2 0 2

unidentified 14 0 14

Figure 5. Estimated quarterly bycatch of a) leatherback and b) loggerhead turtles by the deltalognormal method. The asterisks in loggerhead-NED indicate where there was no actual

observed effort for the quarter. Note change in y-axis scale for NED.

Bycatch Factors

Of the available gear-effort factors in the observer data set, many were eliminated from

consideration for predictors of bycatch rate because of too much missing data, collinearity with

other predictors, or having insignificant effect on the bycatch rate. The remaining subset of

factors (Table 1) was evaluated closely and further screened before entering GLM and regression

tree models. The time-area factors were analyzed in greater detail as month and AREA instead of

as the quarter and NAREA factors that were actually used in bycatch estimation.

a. Leatherback

OFS

92 93 94 95 96 97 98 99 00

0

100

200

300

b. Loggerhead

SEC

NED

0

100

200

300

400 1200

1400

GOM

92 93 94 95 96 97 98 99 00

OFS

92 93 94 95 96 97 98 99 00

0

100

200

300

SEC

NED

0

100

200

300 500

600

GOM

92 93 94 95 96 97 98 99 00

NEC

CAR

0

100

200

300

NEC

CAR

0

100

200

300

*

*

estimated bycatch
131

In swordfish longlining, the use of light sticks is standard and has a significant positive

effect on the turtle bycatch rate (Witzell 1999). Seventy percent of the observed sets used light

sticks. The number of light sticks used in a set (LITENUM) is significantly correlated with the

bycatch rate, as well as with other variables such as the number of surface lights, rattlers, floats,

mainline length, and gangion distance. Obviously, the number of light sticks used is a function

of the length of the longline set. However, the number of hooks set (HOOKSET), hooks between

floats (HKSBFLT), and soak duration (SOAKDUR) have negative correlations with the number

of light sticks. HKSBFLT can be dropped since it is highly correlated HOOKSET. LITENUM,

HOOKSET, and SOAKDUR in the “longline length” class of factors (Table 1) are retained for

further analysis.

Other significant factors retained are gangion length (GANGLEN), which represents the

class of depth-related factors, hook pattern (HKPATRN), the condition of the bait (BAITCON),

and the kind of bait (BAITKND). Of the miscellaneous auxiliary factors in Table 1, those that

are significant and are not correlated with other already selected factors are gangion color

(GANGCOLR) and whether leaders were used (LEAD). The bycatch rate of turtles (lcph) is

highly correlated with the numbers of swordfish caught (swfn) (r=0.30, Pr<0.0001). The

numbers of sharks (srkn) and tunas caught (tunn) are also significantly correlated with swfn

(srkn: r=0.19, Pr<0.0001; tunn: r= -0.15, Pr<0.0001), but their correlations with lcph are not as

strong as that of swfn. The reduced subset of factors is shown in Table 1 as the ones that are not

strikeouts.

An initial GLM with bycatch rate as the response was fitted using the reduced subset of

factors with no interaction terms (Table 4a). The time-area factors of year, month, AREA, with

their two-factor interactions, and the significant gear-effort factors of BAITCON, swfn,

HKPATRN, and LEAD from the initial GLM are retained for input into another GLM (Table

4b). In the second GLM, only swfn among the gear-effort factors remains significant, as are all

time-area factors and their interactions (Table 4b).

Due to the unbalanced nature of the data and the sparse observations particularly of geareffort variables, GLM results could be somewhat misleading. Regression tree modeling is a

robust and flexible method, and can handle nonlinear relationships, high order interactions, and

missing values (De’ath and Fabricus 2000). It gives visual and easily interpretable results

directly on the levels of the factors. It is thus applied to the reduced subset of factor (Table 1) for

another attempt at identifying key factors influencing turtle bycatch rates.

The resultant full regression tree model (size = 96 terminal nodes) is of lcph for all turtle

species combined using the reduced subset of factors in Table 1. The first four nodes are based

on the factors AREA, year, and surface temperature (temp), which account for the largest

proportional reduction (~30%) in deviance (Fig. 6a). Subsequent branching only reduces small

proportions of deviance at a high cost of model complexity. Compare to the full tree of 96

nodes, the pruned tree of 4 nodes only has an increase of residual mean deviance of +0.029 (Fig.

6). The pruned tree in Fig. 6b identifies the terminal nodes and their respective fitted response

(lcph). The length of the vertical branch is roughly proportional to the deviance explained by the

node from which it is grown. The first and most important split is between NED (g) to the right

branch and the other AREAs to the left. The second split is among years within NED – between
132

1992, 1993, 1997 to the left and 1994, 1995, 1999 to the right (no observed data for 1996, 1998).

The left group has already been identified before as the low bycatch years, and the right group as

the high bycatch years (Fig. 3). The third split is by temperature under the years 1994, 1995,

1999 years, with lower temperatures accounting for a lower lcph. The substitution of temperature

in the tree model for month in GLM as one of the three significant predictors of bycatch rate is

not contradictory, as both month and temperature are indicators of seasonality.

Table 4. GLMs of bycatch rate with time-area factors and reduced subset of gear-effort factors.

a. GLM with reduced subset of factors with no interaction terms

NOTE: Due to missing values, only 2026 of 4032 observations can be used in this analysis.

Dependent Variable: lcph

 Sum of

 Source DF Squares Mean Square F Value Pr > F

 Model 69 20.5252181 0.2974669 3.98 <.0001

 Error 1956 146.0204001 0.0746526

 Corrected Total 2025 166.5456182

 R-Square Coeff Var Root MSE lcph Mean

 0.123241 341.1795 0.273226 0.080083

 Source DF Type III SS Mean Square F Value Pr > F

 year 7 0.83073132 0.11867590 1.59 0.1339

 month 11 1.42537395 0.12957945 1.74 0.0603

 AREA 10 4.08954806 0.40895481 5.48 <.0001*

 BAITCON 4 2.02694385 0.50673596 6.79 <.0001*

 BAITKND 5 0.29753419 0.05950684 0.80 0.5516

 LITENUM 1 0.11588307 0.11588307 1.55 0.2129

 HOOKSET 1 0.00787284 0.00787284 0.11 0.7454

 SOAKDUR 1 0.02239024 0.02239024 0.30 0.5840

 swfn 1 0.39373659 0.39373659 5.27 0.0217*

 temp 1 0.11558896 0.11558896 1.55 0.2135

 HKPATRN 21 3.31880536 0.15803835 2.12 0.0022*

 GANGCOLR 5 0.38701935 0.07740387 1.04 0.3941

 LEAD 1 0.23100816 0.23100816 3.09 0.0787*

* significant effect at α=0.1

b. GLM repeating 1. less insignificant factors and with year-month-area interactions

 Sum of

 Source DF Squares Mean Square F Value Pr > F

 Model 290 47.0281703 0.1621661 2.36 <.0001

 Error 1764 121.0550384 0.0686253

 Corrected Total 2054 168.0832087

 R-Square Coeff Var Root MSE lcph Mean

 0.279791 329.2710 0.261964 0.079559

 Source DF Type III SS Mean Square F Value Pr > F

 year 7 1.13290782 0.16184397 2.36 0.0213*

 month 11 2.45835156 0.22348651 3.26 0.0002*

 AREA 10 3.42810423 0.34281042 5.00 <.0001*

 BAITCON 4 0.46219792 0.11554948 1.68 0.1511

 swfn 1 0.26045106 0.26045106 3.80 0.0516*

 HKPATRN 17 1.65370565 0.09727680 1.42 0.1185

 LEAD 1 0.07761345 0.07761345 1.13 0.2877

 year*month 66 7.05860717 0.10694859 1.56 0.0031*

 year*AREA 40 5.11287667 0.12782192 1.86 0.0009*

 month*AREA 53 6.50548469 0.12274499 1.79 0.0005*

 year*mon*AREA 72 4.96852382 0.06900728 1.01 0.4662
133

Figure 6. Regression tree model of time-area and gear-effort factors on the response of bycatch

rate (lcph) of all turtle species combined. The mean residual deviance of the full and pruned

models are given. a) the plot of the deviance against the number of terminal nodes (size) of the

tree model grown, b) shows the pruned model with the fitted response at each node. The length

of the vertical branch is roughly proportional to the deviance explained by the node from which

it is grown.

Full model: lcph = year + month + AREA + BAITCON + BAITKND + LITENUM + HOOKSET +

SOAKDUR + swfn + temp + HKPATRN + GANGCOLR + LEAD

Number of terminal nodes: 96 Residual mean deviance: 0.0652 = 215.1 / 3299

Pruned model: lcph = AREA + year + temp

Number of terminal nodes: 4 Residual mean deviance: 0.09392 = 318.5 / 3391

a b

Key to 6b:

area: a-CAR b-GOM c-FEC d-MAB e-NCA f-NEC g-NED h-SAB I-SAR j-TUN k-TUS

yr: a-92 b-93 c-94 d-95 e-96 f-97 g-98 h-99

Regression trees constructed separately for loggerheads and leatherbacks gave similar

results as for all species combined. Both first split into NED and the other AREAs. For

leatherbacks, the subsequent branches are year, month, and temperature, in order of importance.

For loggerheads, it is year, temperature, and month. However, lower temperature accounts for a

slightly higher catch rate of leatherback, but the opposite is true for loggerhead, so temperature

as a factor may be possibly be species-specific. Given that the intra-annual distribution of

observed effort emulates reported effort and tends to be concentrated in one specific quarter, the

month and temperature factors have to be cautiously interpreted. For NED, fishing peaked in the

3

rd quarter, which is likely to have a higher average temperature than the average temperature of

the other quarters combined. GLM and the regression tree model analysis both essentially

indicate that area and time of fishing as the most important predictors of bycatch rate, and

temperature a possible covariate.

1 20 40 60 80

250 300 350 400 450

size

deviance

|

area:abcdefhijk

yr:abf

temp<62.4375

0.07174

0.20290

0.15710 1.03900
134

Delta-GLM bycatch estimates

Probability of a positive set

Several binomial models were compared by analysis of deviance and the AIC statistic in

a stepwise regression procedure, beginning with the full model that includes time-area factors

(year, quarter, NAREA) and all gear-effort factors in the reduced subset as in Table 4a. None of

the gear-effort factors nor the time factor of quarter contributes significantly to the model. The

“best” model involves only year and NAREA:

bcatch=NAREA+ year + year*NAREA.

The predictors in the model are listed in decreasing order of importance (according to mean

deviance = deviance/df), which has been tested valid for each species (Table 5). NAREA is

again confirmed as the most important factor.

This model was fitted to each species. Leatherbacks and loggerheads, which were most

common in the bycatch and have the most positive sets, share a similar fitted pattern showing

that the expected probability of a positive set (p) is highest in NED, particularly the years 1995

and 1999, and 1994 as well for loggerheads (Fig. 7). The apparent peaks in years 1996

(loggerhead: p = 0.99 ± 0.11 s.e.) and 1998 (leatherback: 0.81 ± 1.74; loggerhead: 0.77 ± 2.39) in

NED, however, are not based on any actual observations in these years (Fig. 3) and carry very

high uncertainty. Other NAREA of moderate probability of bycatch are CAR and NEC. Fitted p

is mostly zero for each year-NAREA for the rare greens, hawksbills, and Kemp’s Ridleys. These

results are in strong agreement with the delta-lognormal estimates and regression tree analysis.

Table 5. Analysis of deviance of the binomial model for the probability of positive set,

bcatch= year+NAREA+year*NAREA.

Response: bcatch

Terms added sequentially (first to last)

 Df Deviance Resid. Df Resid. Dev F Value Pr(F)

a. Leatherback

 NULL 4031 1597.292

 yr 7 45.4679 4024 1551.824 7.29440 1.020363e-008

 narea 5 117.0881 4019 1434.736 26.29813 0.000000e+000

yr:narea 32 100.5779 3987 1334.158 3.52968 8.915000e-011

b. Loggerhead

 NULL 4031 1579.559

 yr 7 47.3457 4024 1532.213 8.70338 1.199050e-010

 narea 5 312.9231 4019 1219.290 80.53281 0.000000e+000

yr:narea 32 81.4260 3987 1137.864 3.27430 1.632598e-009
135

Figure 7. The expected probability of a positive set (+ s.e.) modeled on year, NAREA, and their

interaction in a binomial model for a) leatherbacks; b) loggerheads.

92 93 94 95 96 97 98 99 92 93 94 95 96 97 98 99

year

0.0

0.2

0.4

0.6

0.8

1.0

0.0

0.2

0.4

0.6

0.8

1.0

0.0

0.2

0.4

0.6

0.8

1.0

probability of positive set

CAR GOM

NEC NED

OFS SEC

92 93 94 95 96 97 98 99 92 93 94 95 96 97 98 99

year

0.0

0.2

0.4

0.6

0.8

1.0

0.0

0.2

0.4

0.6

0.8

1.0

0.0

0.2

0.4

0.6

0.8

1.0

probability of positive set

CAR GOM

NEC NED

OFS SEC

Bycatch rate of positive sets

A similar selection process for the binomial model is applied for the gamma model for a)

all species combined, b) leatherbacks and c) loggerheads. Due to sparse data, separate gamma

models cannot be fitted to rare species such as greens, hawksbills and Kemp’s ridley. Instead the

all species fitted model is used for those species. The most important factors remain the timearea factors for each of these three categories, with slight variations on the order and degree of

significance, although NAREA is invariably the most important. A “best” model for all species,

which includes year*NAREA interaction,

 lcph = year + NAREA + quarter +year*NAREA, {lcph>0},

is suitable for the two single species also (Table 6). The residuals of each of the three fitted

models approximate the normal distribution, showing reasonable model fits (Figure 8).

a.

b.
136

Table 6. Analysis of deviance of the gamma log-link models for bycatch rate for positive sets,

{lcph>0}, of a) all species; b) leatherbacks; c) loggerheads.

Response: lcph

Terms added sequentially (first to last)

 Df Deviance Resid. Df Resid. Dev F Value Pr(F)

a. All species

 NULL 428 46.35774

 yr 7 3.369571 421 42.98817 5.184267 0.00001165

 narea 5 4.483531 416 38.50464 9.657414 0.00000001

 quartr 3 1.197666 413 37.30697 4.299571 0.00532184

yr:narea 27 3.554925 386 33.75204 1.418004 0.08322637

b. Leatherbacks

 NULL 200 17.65148

 yr 7 1.459332 193 16.19215 2.641661 0.0130186

 narea 5 1.349223 188 14.84292 3.419279 0.0057858

 quartr 3 0.713974 185 14.12895 3.015657 0.0316335

yr:narea 23 2.550594 162 11.57836 1.405188 0.1149731

c. Loggerheads

 NULL 197 24.97021

 yr 7 3.842434 190 21.12778 6.076786 0.0000026

 narea 5 3.463001 185 17.66478 7.667400 0.0000017

 quartr 3 0.440150 182 17.22463 1.624221 0.1857846

yr:narea 19 2.220263 163 15.00436 1.293649 0.1938116

Figure 8. Pearson residuals of the gamma model lcph=year+NAREA+quarter+year*NAREA,

{lcph>0}, fitted to a) all species; b) leatherbacks; c) loggerheads.

 a b c

-5 0 5

-1

0

1

2

Pearson Residuals

-5 0 5

Quantiles of Standard Normal

-1

0

1

-5 0 5

-1

0

1

Delta-GLM bycatch estimates for leatherbacks and loggerheads are derived from their

respective species-specific fitted binomial and gamma models. The bycatch estimates for each

of the other species are derived from their respective species-specific fitted binomial models and

the all-species gamma model.

The quarterly delta-GLM bycatch estimates for leatherbacks and loggerheads are plotted

in Fig. 9 for a comparison with the delta-lognormal estimates in Fig. 5. In terms of general
137

trends and magnitudes, the point estimates derived from the two methods are quite similar. The

quarterly estimates for leatherbacks in NED 1998, where there was no actual observed effort, are

exceptions. The extremely high leatherback bycatch estimates for the 3rd and 4

th quarters of

NED 1998 are affected by the aforementioned high uncertainty in the predicted probability of

positive set (p), low number of observations, and the status of NAREA as a high bycatch area,

and therefore should be interpreted conservatively. The NED 1995 3

rd quarter peak for

leatherbacks in the delta-lognormal estimates is also present in the delta-GLM estimates, but at

~400 animals compared to the ~600 animals estimated by the delta-lognormal method. For both

leatherbacks and loggerheads in CAR, NEC, NED, and OFS, the patterns of bycatch from both

methods match very well visually (Figs. 5 and 9), especially in the characteristic 3

rd quarter

peaks. The GLM method eliminated many of the zero cells of the lognormal estimates, most

obviously in GOM and SEC for leatherbacks, but annual sums of the bycatch estimates in each

NAREA are of similar magnitudes.

The GLM method produced much higher and probably more realistic CVs for the

estimates (≤13 for loggerheads and leatherbacks, higher still for rare species, see Table 7) than

the delta-lognormal method (≤1, with CV=1 where there is no measure of variability due to lack

of data). This partly reflects that the fits of the GLMs may not optimal, and the linear predictors

do not adequately explain the observed bycatch rates. The main problem may be the sparse data

in combination with the low bycatch rates. The bycatch estimates, CVs, and annual sums of the

rare species by the two methods are tabulated for comparison in Table 7.

Figure 9. Estimated quarterly mean bycatch of a) leatherback and b) loggerhead turtles by the

delta-GLM method. Note change in y-axis scale for second-row panels.

a. Leatherback

OFS

92 93 94 95 96 97 98 99 00

0

100

200

300

b. Loggerhead

SEC

NED

0

100

200

300

500

1000

GOM

92 93 94 95 96 97 98 99 00

OFS

92 93 94 95 96 97 98 99 00

0

100

200

300

SEC

NED

0

200

400

600

4000

8000

GOM

92 93 94 95 96 97 98 99 00

NEC

CAR

0

100

200

300

NEC

mean estimated bycatch

CAR

0

100

200

300

400

200

1000

100

200
138

Table 7. Comparison of the quarterly bycatch estimates and associated coefficient of variation

(CV) from the delta-lognormal and delta-GLM methods for rare species. The extremely high

CV’s from the delta-GLM method resulted from extrapolation to strata with no observed data,

and some of these estimates are so out of range that they are not presented (empty cells).

delta-lognormal delta-GLM delta-lognormal delta-GLM

estimated estimated estimated estimated

yr qtr narea catch cv catch cv yr qtr narea catch cv catch cv

KEMPS RIDLEY 94 1 NEC 1 16 GREEN 95 1 CAR 1 462.9

94 2 NEC 2 16 95 2 CAR 0 462.9

94 3 NEC 26 1 10 16 95 3 CAR 1 462.9

94 4 NEC 6 16 95 4 CAR 0 462.9

97 1 OFS 17 1 14 6.96 93 1 GOM 19 1 4 15.86

97 2 OFS 7 6.96 93 2 GOM 4 15.86

97 3 OFS 1 0.98 1 6.96 93 3 GOM 6 15.86

97 4 OFS 4 0.98 6 6.96 93 4 GOM 4 15.86

92 1 OFS 1 0.98 NA NA 92 1 NEC 3 0.68 4 7.44

Total 49 47 92 2 NEC 48 0.69 12 7.44

92 3 NEC 40 7.44

92 4 NEC 22 7.44

UNIDENTIFIED 95 1 CAR 3 280.8 94 1 NEC 2 11.29

95 2 CAR 1 280.8 94 2 NEC 7 1 4 11.29

95 3 CAR 2 280.8 94 3 NEC 26 1 20 11.29

93 1 GOM 4 15.86 94 4 NEC 13 11.29

93 2 GOM 10 1 4 15.86 92 2 NED 11 4.59

93 3 GOM 6 15.86 92 3 NED 48 4.59

93 4 GOM 4 15.86 92 4 NED 36 0.52 15 4.59

94 1 GOM 20 1 4 12.83 93 2 NED 2 8.98

94 2 GOM 5 12.83 93 3 NED 12 1 12 8.98

94 3 GOM 6 12.83 93 4 NED 5 8.98

94 4 GOM 4 12.83 96 3 NED 11 0.75

97 1 GOM 23 1 10 12.95 96 4 NED 5 0.77

97 2 GOM 9 12.95 98 2 NED 1 0.81

97 3 GOM 17 12.95 98 3 NED 10 0.75

97 4 GOM 8 12.95 98 4 NED 3 0.74

99 1 GOM 24 1 15 9.7 95 1 SEC 9 9.95

99 2 GOM 16 9.7 95 2 SEC 17 9.95

99 3 GOM 17 9.7 95 3 SEC 40 1 7 9.95

99 4 GOM 14 1 13 9.7 95 4 SEC 5 9.95

92 1 NEC 1 0.98 2 10.58 Total 221 268

92 2 NEC 24 1 6 10.58

92 3 NEC 21 1 20 10.58

92 4 NEC 11 10.58 HAWKSBILL 92 1 NEC 2 0.98 2 10.58

93 1 NEC 1 16.85 92 2 NEC 6 10.58

93 2 NEC 2 16.85 92 3 NEC 20 10.58

93 3 NEC 10 16.85 92 4 NEC 18 1 11 10.58

93 4 NEC 4 16.85 98 1 NEC 17 1 2 8.98

99 1 NEC 1 8.23 98 2 NEC 5 8.98

99 2 NEC 4 0.98 5 8.23 98 3 NEC 31 8.98

99 3 NEC 28 8.23 98 4 NEC 18 8.98

99 4 NEC 24 1 15 8.23 96 3 NED 83 10.05

94 2 NED 1 0.98 2 8.49 96 4 NED 30 10.05

94 3 NED 13 0.99 14 8.49 97 1 SEC 16 1 6 10.05

94 4 NED 7 8.49 97 2 SEC 7 10.05

96 3 NED 1 0.98 97 3 SEC 6 10.05

96 4 NED 1 0.98 97 4 SEC 3 10.05

98 3 NED 1 0.98 Total 53 230

92 1 OFS 1 0.98

97 1 OFS 18 1 14 6.96

97 2 OFS 7 6.96

97 3 OFS 1 0.98 1 6.96

97 4 OFS 5 1.01 6 6.96

95 1 SEC 86 0.69 34 4.9

95 2 SEC 85 0.7 68 4.9

95 3 SEC 30 4.9

95 4 SEC 18 4.9

Total 378 454
139

Summary

The delta-lognormal method is used to estimate bycatch of marine turtle in the U.S.

Atlantic pelagic longline fishery in 1992-1999. Estimates are based on quarterly observed effort

and grouped by six fishing areas or NAREAs. To avoid missing or poor estimates where there

are no or very few observation units (set) in a basic year-quarter-NAREA stratum, a criterion is

set so that if a basic stratum has less than 5 (=Nmin) observed sets, the levels of quarter, year, and

then NAREA will be pooled successively in that order until Nmin is achieved. Pooling is

necessary only in the offshore NAREAs of CAR, OFS, and NED and only up to the level of

quarters with rare exceptions. The Nmin of five is selected in an attempt to balance the need for

reasonable estimates and preserving inherent variability among strata. A similar pooling method

was used to estimate retained catch of commercial species from the U.S. Atlantic pelagic

longline fishery with results similar to values reported in the commercial landings reporting

system (Brown et al. 2000). Where there is a paucity of actual observations, this method may be

an acceptable alternative when applied with a consideration of its limitations. The choice of

Nmin, for example, should be subjected to further analysis. The annual summed observed bycatch

and the estimated bycatch obtained by the delta-lognormal method are presented in Table 8. The

CVs for the annual summed estimates are based on the assumption of independence of estimates

among basic strata.

The delta-GLM approach to bycatch estimation is analogous to the delta-lognormal in

that it separately accommodates zero and non-zero observations, which both yield important

information on bycatch. One of advantages offered by the delta-GLM method over the deltalognormal is that it avoids the complication of pooling strata and provides explicit models for the

probability of a set resulting in turtle bycatch in a stratum and the mean bycatch rate for those

positive sets (Stefánsson 1996). GLM also allows the testing of factors influential to bycatch and

the incorporation of those factors in the prediction of bycatch. In terms of bycatch estimates,

however, there is no considerable gain in using the delta-GLM over the delta-lognormal method,

and both are based on the tenuous assumption of a parametric distribution of a rather small

sample data set. Quarterly patterns and trends in the bycatch of each NAREA correspond well

between the two methods (Figs. 5 and 9). Although the delta-GLM method in some cases

resulted in a more even distribution of bycatch intra-annually, the annual summed bycatch

estimates are reasonably close to those of the delta-lognormal (Table 7). The delta-GLM

method is more cumbersome than the delta-lognormal, and the GLM models are by no means

optimally fitted. The binomial models fitted only accounted for approximately 20-30% of the

total deviance or variation explained (Table 5), while the gamma models are slightly better with

30-40% (Table 6). The CVs of the bycatch estimates from the delta-GLM method may suffer

from poor model fits, but may actually be more realistic than those of the delta-lognormal

estimates. The primary reason for high CVs, however, is the sparseness of the data and also the

nature of the data, in which the probability of a positive set tends to be extremely low.

Loggerheads and leatherbacks are the marine turtle species most often caught in pelagic

longline. Results of the bycatch analysis show that NEC and NED are the two areas of highest

bycatch of these species (Fig. 5), and peak bycatch occurred in the 3rd quarter of the year at the

height of fishing effort (Fig. 3). Considering the relatively low effort in NED compared to NEC,

their comparable magnitude of estimated bycatch marks NED as an area of extraordinarily high
140

bycatch rate. There is no distinguishable monotonic trend in bycatch, but that may be affected

by the lack of observed effort in some quarters and for the entire 1996 and 1998 for NED.

Analysis of the observed data show that time-area factors are far more influential on

bycatch than gear-effort factors. The task remains the unraveling of the biological and physical

factors that are masked by time and space.

Table 8. Annual summed observed and delta-lognormal estimates of total marine turtle bycatch

and the subset that were dead when released in the U.S. pelagic longline fishery (CL= confidence

limit; CV =coefficient of variation).

observed estimated upper lower estimated upper lower

species year catch catch 95% CL 95% CL CV dead 95% CL 95% CL CV

loggerhead 92 6 293 1149 78 0.79 0

loggerhead 93 23 417 1414 142 0.69 9 46 2 1

loggerhead 94 88 1344 2392 859 0.3 31 158 6 1

loggerhead 95 129 2439 4542 1405 0.33 0

loggerhead 96 13 917 2713 322 0.6 2 10 0 0.98

loggerhead 97 17 384 1281 124 0.68 0

loggerhead 98 15 1106 3225 395 0.59 1 5 0 0.98

loggerhead 99 64 991 2089 510 0.39 23 117 5 1

leatherback 92 28 914 2716 353 0.6 88 449 17 1

leatherback 93 66 1054 2603 463 0.49 0

leatherback 94 42 837 2433 328 0.59 0

leatherback 95 61 934 2093 520 0.43 0

leatherback 96 10 904 2074 231 0.44 0

leatherback 97 7 308 1498 66 0.96 0

leatherback 98 4 400 1411 120 0.72 0

leatherback 99 45 1012 2786 410 0.55 0

green 92 10 87 266 29 0.62 30 154 6 1

green 93 2 31 158 6 1 0

green 94 2 33 169 6 1 0

green 95 1 40 205 8 1 0

green 96 0 16 60 4 0.76 2 10 0 0.98

green 98 0 14 52 4 0.75 1 5 0 0.98

hawksbill 92 1 20 102 4 1 0

hawksbill 97 1 16 82 3 1 0

hawksbill 98 1 17 87 3 1 0

Kemp's Ridley 92 0 1 5 0 0.98 0

Kemp's Ridley 94 1 26 133 5 1 0

Kemp's Ridley 97 1 22 112 4 1 0

unidentified 92 1 26 133 5 1 0

unidentified 93 2 31 158 6 1 0

unidentified 94 2 34 173 7 1 0

unidentified 95 4 171 587 50 0.7 0

unidentified 96 0 2 10 0 0.98 0

unidentified 97 2 47 241 9 1 0

unidentified 98 0 1 5 0 0.98 0

unidentified 99 3 66 338 14 1 0
141

Literature Cited

Berkeley, S., E. Irby, and J. Jolley. 1981. Florida’s commercial swordfish fishery: longline gear

and methods. Florida Sea Grant Marine Advisory Bull. MAP-14, 23 pp.

Brown, C.A. In press. Revised estimates of bluefin tuna dead discards by the U.S. Atlantic

pelagic longline fleet, 1992-1999. International Commission for the Conservation of

Atlantic Tunas, Collected Volume of Scientific Papers Working Document

SCRS/2000/97.

Brown, C.A., J. Cramer, and A. Bertolino. 2000. Estimates of bycatch by the U.S. Atlantic

pelagic longline fleet during 1993-1998. U.S. Department of Commerce NOAA

Technical Memorandum NMFS-F/SPO-46:17.

Cramer, J. and H. Adams. 2000. Large pelagic logbook newsletter – 1998. U.S. Department of

Commerce NOAA Technical Memorandum NMFS-SEFSC-433, 25 pp.

De’ath, G. and K. E. Fabricus. 2000. Classification and regression trees: a powerful yet simple

technique for ecological data analysis. Ecology 81: 3178-3192.

Hoey, J. 1998. NEFSC pelagic longline data review & analysis of gear, environmental, and

operating practices that influence pelagic longline interactions with sea turtles. Final

contract report NOAA Contract - 50EANA700063, National Fisheries Institute, Inc.,

Arlington, Va., 32 pp.

Hoey, J. and A. Bertolino. 1988. Review of the U. S. fishery for swordfish, 1978 to 1986.

International Commission for the Conservervation of Atlantic Tunas (ICCAT), Collected

Volume of Scientific Papers 27:230-239.

Johnson, D. R., C. Yeung, C. A. Brown 1999. Estimates of marine mammal and marine turtle

bycatch by the U.S. Atlantic pelagic longline fleet in 1992-1997. U.S. Department of

Commerce NOAA Technical Memorandum NMFS-SEFSC-418, 70 pp.

Lee, D. W. and C. J. Brown. 1998. SEFSC pelagic observer program data summary for 1992-

1996. U.S. Department of Commerce NOAA Technical Memorandum NMFS-SEFSC408, 21 pp.

MathSoft, 1997. S-PLUS 4 Guide to Statistics. Data Analysis Products Division, MathSoft, Inc.

Seattle, WA.

Myers, R. A. and P. Pepin. 1990. The robustness of lognormal-based estimators of abundance.

Biometrics 46:1185-1192.

Pennington, M. 1983. Efficient estimators of abundance for fish and plankton surveys.

Biometrics 39:281-286.
142

Stefánsson, G. 1996. Analysis of groundfish survey abundance data: combining the GLM and

delta approaches. ICES Journal of Marine Science 53:577-588.

Syrjala, S. E. 2000. Critique on the use of the delta distribution for the analysis of trawl survey

data. ICES Journal of Marine Science 57:831-842.

Witzell, W. N. 1999. Distribution and relative abundance of sea turtles caught incidentally by

the U.S. pelagic longline fleet in the western North Atlantic Ocean, 1992-1995. Fishery

Bulletin 97:200-211.

Yeung, C. 1999a. Revised mortality estimates of marine mammal bycatch in 1992-1997 based

on serious injury guidelines. U.S. Department of Commerce NOAA Technical

Memorandum NMFS-SEFSC-429, 23 pp.

Yeung, C. 1999b. Estimates of marine mammal and marine turtle bycatch by the U.S. Atlantic

pelagic longline fleet in 1998. U.S. Department of Commerce NOAA Technical

Memorandum NMFS-SEFSC-430, 26 pp.
143

CHAPTER 3. SIZES OF SEA TURTLES INCIDENTALLY CAPTURED IN

ATLANTIC AND MEDITERRANEAN PELAGIC LONGLINE FISHERIES

AND THEIR NATAL ORIGINS

Wayne N. Witzell and Sheryan P. Epperly

Pelagic longline fisheries may impact several species of sea turtle. However, it is unlikely

that the U.S. Atlantic fleet encounters substantial numbers of hard-shell turtles other than

loggerheads. Witzell (1999) edited the U.S. pelagic logbook to include only leatherback and

loggerhead turtles. This was based on the known distribution, abundance, and biology of sea

turtles in the areas fished, and the fact that some vessel captains and observers were unable to

accurately identify turtles encountered6. There is the possibility hard shell turtles other than

loggerheads could occasionally be taken, but there have been no photographs taken to date or

green, ridley, or hawksbill turtles taken by the U.S. Atlantic fleet.

Sizes

There is little data on the sizes of sea turtles incidentally captured in various Atlantic

Ocean and Mediterranean Sea longline fisheries. Data for loggerhead sea turtles are summarized

in Table 1. No information was found on incidentally caught leatherback turtle sizes in any

Atlantic or Mediterranean Sea longline fishery.

The most pertinent published study is by Witzell (1999) who summarized observer data

from the U.S. Grand Banks swordfish fishery. These data indicate that immature loggerhead

turtles (41-70 cm CCL) are captured, with a mean size of 55.9 cm. Bolten et al. (1993) reported

that turtles from an eastern Atlantic tuna fishery ranged in size form 42-82 cm CCL. The Witzell

(1999) data and the Bolten et al. (1993) data are very similar and are presented in Fig. 1.

Bolten et al. (1993) reported that dip net caught turtles were significantly smaller (12.5-

62.5 CCL) than the longline caught turtles (42.5-67.5 CCL) from the same area, indicating that

the longlines selectively harvest larger immature turtles than the dip nets. Conclusions drawn

from results of expanded sample sizes of the Azores dip net (Bjorndal et al. 2000) and longline

caught turtles (Bolten et al. 20017) remain unchanged (Fig. 2).

The loggerhead turtles caught in the Mediterranean Sea also appear to be immature

turtles. The largest sample size (N=856) is reported by Aguilar et al. (1995) from the western

Mediterranean. These animals averaged 48.1 cm (27-76 cm). Turtles from the central

 

6 Dr. Molly Lutcavage, New England Aquarium, Boston, MA. Personal Communication (phone) to Wayne Witzell,

National marine Fisheries Service, SEFSC, Miami, Fla., January 30, 2001.

7 Bolten, A.B., H. Martins, E. Isidro, R. Ferreira, M. Santos, A. Giga, B. Riewald, and K. Bjorndal. Preliminary

results of an experiment to evaluate effects of hook type on sea turtle bycatch in the swordfish longline fishery in the

Azores. Bolten, A.B., University of Florida, E-mail to Nancy Thompson and Sheryan Epperly, National Marine

Fisheries Service, SEFSC, Miami, Fla., Jan. 14. 2001.
144

Mediterranean Sea ranged from 35-75 cm (Argano et al. 1992, Panou et al. 19928) and averaged

57.0 cm (Argano et al. 1992).

Loggerheads of the sizes reported above captured in the open ocean most likely are

pelagic juveniles, although this size range also represents the overlap in sizes of pelagic and

small benthic juveniles (Bjorndal et al. 2000). Laurent et al. (1998) proposed that between the

strict oceanic pelagic stage and the benthic stages, immature turtles may live through an

intermediate neritic stage in which they switch between pelagic and benthic foods and habitats.

Furthermore, it is likely that some animals are not pelagic juveniles, as adults are known to make

migrations between foraging grounds and nesting beaches across open ocean waters (see Part I.)

and benthic juveniles have been reported to migrate well offshore seasonally (Epperly et al.

1995, Shoop and Kenney 1992, Mullin and Hoggard 20009).

Natal Origins

There is no information about the natal origins of loggerheads captured by the Atlantic

fleets. However, studies of foraging ground animals on the North American continental shelf

and estuarine waters and of stranded animals in the western North Atlantic indicate that animals

of different origins mix on the foraging grounds, with the large South Florida subpopulation

dominating everywhere, but with decreasing contribution northward (see Part I and TEWG 1998,

2000). Studies of pelagic animals captured in the vicinity of the Azores indicated that 71-72% of

the animals originated from the South Florida subpopulation, with 17-19% of the animals

originating from the northern subpopulation and 10-11% from the Quintana Roo, Mexico

subpopulation (Bolten et al. 1998). The Azores samples, dipnetted from the ocean’s surface,

represent an admixture of pelagic animals. The size distribution of these animals is significantly

different (smaller) than animals taken on the longlines (Fig. 2). If there is no sorting by natal

origin in the pelagia and these smaller animals represent the same genetic mix as would be found

in the larger animals taken by the longline, we can assume that these results also represent the

natal origins of animals caught by the U.S. domestic longline fleet on the high seas in the eastern

Atlantic.

In the Mediterranean Sea, 45-47% of the loggerheads captured in pelagic longlines

(presumably pelagic stage animals) originate from western North Atlantic rookeries (Laurent et

al. 1998) whereas none of the animals captured in trawls (presumably benthic stage animals)

were from the western North Atlantic. Of the animals from the Western North Atlantic, 2% were

from the northern subpopulation, the remainder were attributed to the South Florida

subpopulation. Thus, it appears that both the eastern and western basins of the Mediterranean

 

8

Panou, A., G. Antypas, Y.Giannopoulos, S. Moschonas, D.G., D. Mourelatos, G. Mourelatos, Ch. Mourelatos, P.

Toumazatos, L. Tselentis, N.Voutsinas, and V.Voutsinas. 1992. Incidental catches of loggerhead turtles, Caretta

caretta, in swordfish long lines in the Ionian Sea, Greece. Unpublished Report. Institute of Zoology, University of

Munich, Germany, 8 pp

9

 Mullin, K.D. and W. Hoggard. 2000. Visual surveys of cetaceans and sea turtles from aircraft and ships, p. 111-

322. In R.W.Davis, W.E. Evans, and B. Würsig, eds. Cetaceans, sea turtles and seabirds in the northern Gulf of

Mexico: distribution, abundance and habitat associations. Unpublished report. USGS/BRD/CR--1999-0006, OCS

Study MMS 2002-002. Department of Marine Biology, Texas A&M University, Galveston, Texas.
145

Sea are utilized by pelagic loggerheads originating from the western North Atlantic but these

animals leave the Mediterranean before switching to their benthic life stage.

In fall 2000, 18 genetic samples were taken from loggerhead turtles captured on the

Grand Banks and 16 of them have been sequenced10. Two haplotypes were discerned: A

(56.3%) and B (43.7%). Haplotypes A and B have been found in all 3 nesting assemblages in the

United States and B also has been found in the nesting population of Mexico and Greece

(Encalada et al. 1998). The sample size is too small to yet determine the proportions of the

subpopulations represented.

 

10 Peter Dutton, National Marine Fisheries Service, SWFSC, La Jolla, Calif. Personal Communication (E-Mail) to

Sheryan Epperly, National Marine Fisheries Service, SEFSC, Miami, Fla., January 20, 2001.
146

Literature Cited

Aguilar, R., J. Mas, and X. Pastor. 1995. Impact of Spanish swordfish longline fisheries on the

loggerhead sea turtle Caretta caretta population in the western Mediterranean. U.S.

Department of Commerce NOAA Technical Memorandum NMFS-SEFSC-361:1-6.

Argano, R. R. Basso, M. Cocco, G.Gerosa. 1992. Nouvi dati sugli spostamenti di tartaruga

marine comune (Caretta caretta) in Mediterraneo. Bollettino Musel Istitiuti Universita

Genova 56-57:137-163.

Bjorndal, K.A., A.B. Bolten, and H.R. Martins. 2000. Somatic growth model of juvenile

loggerhead sea turtles Caretta caretta: duration of pelagic stage. Marine Ecology Progress

Series 202:265-272.

Bolten, A.B., H.R. Martins, K.A. Bjorndal, J. Gordon. 1993. Size distribution of pelagic-stage

loggerhead sea turtles (Caretta caretta) in the waters around the Azores and Madeira.

Arquipelago 11A:49-54.

Bolten, A.B., K.A. Bjorndal, and H.R. Martins. 1994. Life history model for the loggerhead sea

turtle (Caretta caretta) population in the Atlantic: Potential impacts of a longline fishery.

U.S. Department of Commerce NOAA Technical Memorandum. NMFS-SWFSC-201:48-55.

Bolten, A.B., K.A. Bjorndal, H.R. Martins, T. Dellinger, M.J. Biscoito, S.E. Encalada, and B.W.

Bowen. 1998. Transatlantic developmental migrations of loggerhead sea turtles

demonstrated by mtDNA sequence analysis. Ecological Applications 8:1-7.

Encalada, S.E., K.A. Bjorndal, A.B. Bolten, J.C. Zurita, B. Schroeder, E. Possardt, C.J. Sears,

and B.W. Bowen. 1998. Population structure of loggerhead turtle (Caretta caretta) nesting

colonies in the Atlantic and Mediterranean as inferred from mitochondrial DNA control

region sequences. Marine Biology 130:567-575.

Epperly, S.P., J. Braun, A.J. Chester, F. A Cross, J.V. Merriner, and P.A. Tester. 1995. Winter

distribution of sea turtles in the vicinity of Cape Hatteras and their interactions with the

summer flounder trawl fishery. Bulletin of Marine Science 56:547-568.

Laurent, L., P. Casale, M.N. Bradai, B.J. Godley, G. Gerosa, A.C. Broderick, W. Schroth, B.

Schierwater, A.M. Levy, D. Freggi, E.M. Abd El-Mawla, D.A. Hadoud, H.E. Gomati, M.

Domingo, M. Hadjichristophorou, L. Kornaraky, F. Demirayak, and Ch. Gautier. 1998.

Molecular resolution of marine turtle stock composition in fishery bycatch: a case study in

the Mediterranean. Molecular Ecology 7:1529-1542.

Shoop, C.R. and R.D. Kenney. 1992. Seasonal distributions and abundances of loggerhead and

leatherback sea turtles in waters of the northeastern United States. Herpetological

Monographs 6:43-67.
147

Turtle Expert Working Group. 1998. An assessment of the Kemp’s ridley (Lepidochelys kempii)

and loggerhead (Caretta caretta) sea turtle populations in the Western North Atlantic.

U.S. Department of Commerce NOAA Technical Memorandum NMFS-SEFSC-409,

96pp.

Turtle Expert Working Group. 2000. Assessment update for the Kemp’s ridley and loggerhead

sea turtle populations in the Western North Atlantic. U.S. Department of Commerce

NOAA Technical Memorandum NMFS-SEFSC-444, 115 pp.

Witzell, W.N. 1999. Distribution and relative abundance of sea turtles caught incidentally by the

U.S. pelagic longline fleet in the western North Atlantic ocean, 1992-1995. Fishery Bulletin

97:200-211.
148

Table 1. Documented loggerhead sea turtle sizes incidentally captured by various longline fleets.

____________________________________________________________________________________

Mean (cm) Range StDev N

____________________________________________________________________________________

Atlantic Ocean

Location fished Grand Banks 55.9 41-70 6.5 98

Vessel Flag U.S.A.

Target Species Swordfish

Reference Witzell (1999)

Location fished Azores -- 42-82 -- 224

Vessel Flag Spain

Target Species Tuna, Swordfish, Blue Sharks

Reference Bolten et al. (1993, 1994, 200111)

Mediterranean Sea

Location Fished Western Med. Sea 48.1 27-76 - 856

Vessel Flag Spain

Target Species Swordfish

Reference Aguilar et al. (1995)

Location Fished Ionian Sea 35-75 20-100 - 59

Vessel Flag Greece

Target Species Swordfish

Reference Panou et al. (1992)12

Location Fished Central Med. Sea 57.0 35-69.5 9.9 38

Vessel Flag Italy

Target Species Swordfish

Reference Argano et al. (1992)

____________________________________________________________________________________

 

11 Bolten, A.B., H. Martins, E. Isidro, R. Ferreira, M. Santos, A. Giga, B. Riewald, and K. Bjorndal. Preliminary results of an

experiment to evaluate effects of hook type on sea turtle bycatch in the swordfish longline fishery in the Azores. Bolten, A.B.,

University of Florida, E-mail to Nancy Thompson and Sheryan Epperly, NMFS/SEFSC/Miami, FL, January 14. 2001.

12 Panou, A., G. Antypas, Y.Giannopoulos, S. Moschonas, D. Mourelatos, G. Mourelatos, Ch. Mourelatos, P. Toumazatos,

L.Tselentis, N.Voutsinas, and V.Voutsinas. 1992. Incidental catches of loggerhead turtles, Caretta caretta, in swordfish long

lines in the Ionian Sea, Greece. Unpublished Report. Institute of Zoology, University of Munich, Germany, 8 pp
149

Figure 1. Sizes of longline caught loggerhead (Caretta caretta) turtles from the U.S. Grand

Banks swordfish fishery (above) (original data from Witzell 1999) and the Spanish Azores tuna

fishery (below) (Bolten et al. 1993; data from Figure 2).

0

5

10

15

20

25

30

35

36-40 41-45 46-50 51-55 56-60 61-65 66-70 71-75 76-80

Carapace Length (SCL) cm

Number of Turtles

X = 55.9

SD = 6.5

N = 98

0

5

10

15

20

36-40 41-45 46-50 51-55 56-60 61-65 66-70 71-75 76-80

Carapace Length (SCL) cm

Number of Turtles

Grand Banks

Azores Islands N = 38

X = 55.9

SD = 6.5

N = 98
150

Figure 2. Length frequency histogram of dip netted and longline caught loggerhead turtles near

the Azores (reproduced from Bolten et al. 1993).
151

Figure 3. Length frequency of loggerhead turtles from the Azores Islands. Hatched bars = dip

netted turtles, N=1,692 (includes less than 100 longline captured turtles, also) (Bjorndal et al.

2000). Solid bars = longline experiment, July-December 2000, N=22413. The frequency

distributions are significantly different (Kolmogorov-Smirov two-sample test, (KS=0.6522,

P<0.0001).

 

13 Bolten, A.B., H. Martins, E. Isidro, R. Ferreira, M. Santos, A. Giga, B. Riewald, and K. Bjorndal. Preliminary

results of an experiment to evaluate effects of hook type on sea turtle bycatch in the swordfish longline fishery in the

Azores. Bolten, A.B., University of Florida, E-mail to Nancy Thompson and Sheryan Epperly, National Marine

Fisheries Service, SEFSC, Miami, Florida, January 14, 2001.

5 15 25 35 45 55 65 75 85

Curved Carapace Length (cm)

0

10

20

30

40

50

Percent
152

CHAPTER 4. REVIEW OF POST CAPTURE MORTALITY AND

SELECTED MORTALITY RATES

Office of Protected Resources, National Marine Fisheries Service

The Office of Protected Resources (F/PR) was tasked by William Hogarth, Deputy

Assistant Administrator for Fisheries to review information on marine turtle mortality in longline

fisheries and to make a recommendation regarding the estimation of post-interaction mortality.

In addition, F/PR was directed to convene a workshop to further address the issue of mortality

estimation. Finally, the Southeast Region requested input on this issue in order to incorporate

any new information into their analyses of the impact of the Atlantic longline fishery on marine

turtles.

Summary Findings14

1. F/PR recommends the use of revised serious injury/mortality criteria for defining levels of

injury to turtles interacting with longline fishing gear (see below).

2. F/PR recommends that 50% of longline interactions with all species of sea turtles be

classified as lethal and 50% be classified as non-lethal. The 50% lethal classification is based on

our analysis and evaluation of the range of mortality discussed is several investigations for

lightly and deeply hooked turtles. Our recommendation assumes additional mortality under

normal fishing conditions, where turtles are infrequently boarded, and gear can be assumed to be

left on turtles at a greater rate than when an observer handles a turtle for a defined experiment.

Serious Injury/Mortality Criteria

In November, F/PR received from SEC staff a preliminary strawman of serious

injury/mortality criteria (Attachment A). F/PR reviewed the document in consultation with SEC

sea turtle staff, who agreed that a revision was needed for greater clarity and to focus reviewer

comments. F/PR revised the strawman (Attachment B) and solicited input from 33 persons

including veterinarians, scientists, and gear and industry experts. F/PR received a total of 7

responses from 4 veterinarians, 2 scientists, and 1 gear/industry expert. A copy of all responses

is attached, including comments from F/ST staff, responding to the draft strawman developed by

the SEC (Attachment C). Attachments referred to herein are in Appendix 4.

 

14 Donald R. Knowles, National Marine Fisheries Service, PR, Silver Spring, Md. Personal Communication

(Memo) to Joseph E. Powers, National Marine Fisheries Service, SERO, St. Petersburg, Fla.. Marine turtle mortality

resulting from interactions with longline fisheries. 9 pp., January 4, 2001. Attachments referred to therein are in

Appendix 4.
153

Reviewer Comments

Respondents were not able to quantitatively assess criteria for determining whether a

particular interaction between a turtle and longline gear will result in mortality. This is not

surprising given the multitude of factors involved, including, but not limited to, the nature of the

interaction, the duration of the interaction (i.e., time elapsed from the interaction to removal of

the animal from the gear), environmental conditions at capture, species, physiological status

when captured (e.g., turtle recently surfaced, turtle attempting to surface), turtle size, turtle

behavior as the gear is retrieved, how the turtle is handled and the lack of baseline information

on what constitutes a healthy turtle from which criteria for injury may be established. While not

providing quantitative guidance, respondents did however provide important qualitative

assessments of longline interactions. These assessments ranged from likely to recover (for

superficial external hooking injuries) to likely long-term impact with eventual death if not treated

(for ingested hooks). In general, respondents raised more questions than they answered. These

questions are useful in that they will help to develop and focus the upcoming workshop to further

discuss these complex issues. Despite the questions, and range of comments, there were a

number of responses in common that shed light on the assessment of lethal and non-lethal

interactions between sea turtles and pelagic longline gear.

Two respondents suggested variations on the injury categories described in the strawman.

Their comments generally agreed with the strawman’s categories, except that both suggested an

additional description for ‘moderate’ or ‘minor’ injury that would include visible injuries that are

determined to be superficial, and interactions where the gear has been removed and the animal is

not weakened. PR assumes that injuries described in this category would not result in mortality,

but might reduce the animal’s fitness. Therefore, a new category of observed “minor or

moderate” injury is proposed.

The remaining comments can be grouped into three general categories: hooking, hooking

with trailing line, and entanglement. The respondents generally indicated that the degree of

damage that may result from hooking is dependent upon where on the body the hook penetrated,

the depth of penetration, and the length of time the hook is present. Infection, whether localized

or systemic, was another important factor in determining whether the turtle would survive the

hooking event. One respondent stated that he had seen turtles with ingested hooks that were

apparently healthy while other ingested hooks can cause death. Another respondent stated that

any turtle with an ingested hook could be in grave danger. Physiological stresses resulting from

the hooking event (e.g., fighting the hook) was also pointed out as a concern. Respondents

categorized trailing line (i.e., line that is left on the turtle), particularly line that is trailing from

an ingested hook, as a significant risk. Line trailing from an ingested hook is likely to be

swallowed which may occlude the gastrointestinal tract and lead to eventual death. Trailing line

may become snagged and may result in further entanglement with potential loss of appendages

that may affect mobility, feeding, predator evasion, or reproduction. Several respondents felt

that the level of risk is dependent on the size and robustness of the turtle in relation to the length

of line that is left on the turtle. Characteristics of the monofilament line may also play a role in

the risk of further entanglement.
154

F/PR believes that the reviewer’s responses clearly indicate that interactions with

longline gear pose a risk to the turtle and that many variables affect that level of risk. These

variables cannot be quantitatively ascertained from the existing observer records. Assigning a

mortality level to each specific type of interaction based on existing records and current

knowledge would be extremely difficult. Revised criteria for determining injury are provided

below.

Revised Criteria for Determining Injury for Sea Turtle-Longline Fishery Interactions

I. Non-serious injuries:

1. Entanglement in monofilame nt line (mainlines, gangion line, or float line) where there

are no visible injuries (cuts and/or bleeding), the gear is completely removed, and the

turtle swims strongly away from the vessel.

II. Minor or Moderate injury:

1. Visible injuries determined to be superficial and interactions where the gear has been

removed and the animal is not weakened (this category would not include ingested hooks

under III. 4, below).

III. Serious injuries may result in mortality, or reduced ability to contribute to the population

when released alive after the interaction:

1. Entanglement in monofilament line (mainline, gangion line, or float line) that directly or

indirectly interferes with mobility such that feeding, breeding or migrations are impaired.

2. Entanglement of monofilament line (mainline, gangion line, or float line) resulting in

substantial wound(s) (cuts, constriction, bleeding) on any body part.

3. Hooking external to the mouth resulting in substantial wound(s) (cuts, constriction,

bleeding) with or without associated external entanglement and/or trailing attached line.

4. Ingestion of hook in beak or mouth (visible), with or without associated external

entanglement and/or trailing attached line.

5. Ingestion of hook in the mouth, throat area, esophagus or deeper, with or without

associated external entanglement and/or trailing attached line.

Estimating Post-Interaction Sea Turtle Mortality

F/PR has reviewed the results of research on post-hooking mortality of sea turtles

interacting with longline fisheries and has discussed results with several experts. The research to

determine post-hooking mortality is based primarily on satellite tracking of hard-shell turtles

after their treatment for hooking/entanglement and release. The transmitters are placed on the

carapace of the turtle and data are downloaded from a satellite link at pre-determined intervals

when the turtle is on the surface. Some transmitters also measure the turtle’s diving behavior.

The lack of any satellite transmission after 30 days may be categorized as an unsuccessful track

and probable turtle mortality. Properly functioning transmitters should operate anywhere from

9-18 months. The failure rate of transmitters is minimal and attachment to the turtle shell is
155

certain, so that the sinking of the turtle after death is assumed when transmissions are no longer

received after 30 days. However it is important to note that this one-month criterion cannot be

evaluated for its direct relation to mortality and the actual “cut-off” for assuming mortality may

be significantly higher or may be lower.

Post-Hooking Studies: Hawaii

Studies aimed at elucidating post-longline hooking mortality using satellite telemetry

devices are ongoing in the Hawaii longline fishery operating in the north central Pacific. These

studies have focused on olive ridleys, loggerheads, and to a lesser extent green turtles (G. Balazs,

personal communication15). Turtles selected as part of the study are limited to those that are

lightly hooked or have deeply ingested hooks. The term “lightly hooked” refers to hooks that are

imbedded externally on the turtle or imbedded in the mouth or beak, and that can be removed

with relative ease and without causing additional injury. The term “deep ingested” implies a

hook that is not visible when the mouth is open or only part of the hook can be seen when

viewed in the open mouth, in either case the “deep ingested” hook cannot be removed in the field

without causing further harm. Turtles selected to carry transmitters are boarded using dip nets.

Observers remove the hook and all line before beginning the transmitter attachment on lightly

hooked turtles. The treatment of turtles that have deep ingested hooks differs in that the line is

removed to a point as close to the hook as possible, but the hook (and in some cases attached

line) remains. The transmitter attachment procedure takes several hours from start to finish, after

which the turtle is released. There were no turtles studied that were entangled only and no

control turtles (i.e., non-hooked, wild turtles) in the same environment have been tagged as part

of this study. Ongoing studies in the Eastern Tropical Pacific (ETP) may provide a control group

of turtles against which to compare those tagged in the north central Pacific. However, ETP

sample sizes remain small and life history stages differ for some species (e.g., mature adult olive

ridleys intercepted during their breeding migrations in the ETP) thus complicating comparability

(P. Dutton, personal communication16).

Results of the Hawaii-based study, to date, are summarized in a November 2000 report

by the NMFS Southwest Fisheries Science Center (NMFS 2000a

17). The data are complex and

some of the tracking is ongoing. However, initial results are available. The study included 35

loggerheads, 11 olive ridleys, and 3 green turtles. Of the 49 turtles outfitted with satellite

transmitters (30 deep ingested, 19 lightly hooked), 30.6% (n=15) produced no transmissions or

transmissions that did not exceed one month in duration (these are not considered “successful

trackings”). Of these 15 turtles, four were lightly hooked (21.1%) and 11 were deeply hooked

(36.7%). Analyses to test for differences in transmission time distribution, mean transmission

time and mean distance traveled in the Hawaii-based study between lightly hooked and deeply

 

15 George Balazs, National Marine Fisheries Service, SWFSC, Honolulu, Hawaii. Personal Communication to

Barbara Schroeder, National Marine Fisheries Service, PR, Silver Spring, Md.

16 Peter Dutton, National Marine Fisheries Service, SWFSC, La Jolla, Calif. Personal Communication to Barbara

Schroeder, National Marine Fisheries Service, PR, Silver Spring, Md., January 2001.

17 NMFS. 2000a. Post-hooking survival research of marine turtles (analyzed by D. Parker and G. Balazs).

Unpublished Report. National Marine Fisheries Service, SWFSC, Honolulu, Hawaii, November 2000, 20 pp.
156

hooked turtles revealed no significant differences. Twenty-seven percent (27%) of the lightly

hooked loggerheads and 42% of the deeply hooked loggerheads were classified as nonsuccessful tracks. Seventeen percent (17%) of the lightly hooked olive ridleys and 20% of the

deeply hooked olive ridleys were classified as non-successful tracks. Sample sizes of green

turtles (n=3) were too small to produce meaningful results.

Reliability of transmitters is an important consideration in studies employing satellite

telemetry to elucidate the behavior and migrations of sea turtles. Four “types” of transmitters

were used in the Hawaii-based study. No significant differences were found in the comparison

of different duty cycles or battery types for the duration of tracking for turtles that produced

successful tracks (NMFS 2000b

18).

We believe the cessation of transmissions within a one-month period and the absence of

transmissions post-release (collectively termed “non-successful tracks) from 30.6% of the tagged

turtles can be considered a minimal indicator of post-hooking mortality in this study. We believe

it is unlikely that mechanical failure of the transmitters or separation of the transmitter from the

turtle would cause such a result. Satellite telemetry studies on post-nesting hawksbills in the

Caribbean, utilizing similar, though not identical units, resulted in only one tagged turtle (2.5%)

from which no transmissions were documented and catastrophic failure of the telemetry unit is

suspected (B. Schroeder, personal communication19). Studies deploying over 100 similar,

though not identical tags (primarily Telonics ST-14 units and a smaller number of Wildlife

Computer SDR units) on post-nesting loggerhead and green turtles in Florida and studies on

post-nesting green turtles in Hawaii and elsewhere in the Pacific have resulted in no total failures

(Balazs, personal communication20 and Schroeder, personal communication21). In these studies,

cessation of transmissions within short periods of time (e.g., less than one month, but not total

failure) are also relatively uncommon when proven attachment techniques and transmitter

designs are used.

Post-Hooking Studies: Eastern Atlantic

Similar, though not identical studies are being conducted in the eastern Atlantic in an

attempt to elucidate post-longline hooking mortality of immature loggerheads. This research

includes wild-captured turtles (i.e., not hooked) from the same area as turtles incidentally

captured in the Azores swordfish longline fishery (considered “control turtles”) and was

conducted in two discrete segments - Fall 1998 and Summer 2000 using Wildlife Computers

 

18 NMFS. 2000b. Post-hooking survival research of marine turtles: duty cycle and battery configuration analyses.

Unpublished Report. National Marine Fisheries Service, SWFSC, Honolulu, Hawaii, Oct. 2000, 8 pp

19 Barbara Schroeder, National Marine Fisheries Service, PR, Silver Spring, Md. Personal Communication.

20 George Balazs, National Marine Fisheries Service, SWFSC, Honolulu, Hawaii. Personal Communication to

Barbara Schroeder, National Marine Fisheries Service, PR, Silver Spring, Md., January 2001.

21 Schroeder, B., National Marine Fisheries Service, PR, Silver Spring, Md,. Personal Communication.
157

satellite-linked Time-Depth Recorders (Bjorndal et al. 199922; Riewald et al. 200023). Sample

sizes are considerably smaller than the Hawaii-based study, 9 turtles have been wild-captured, 3

were lightly hooked (in mouth), and 6 turtles were deeply hooked. As in the Hawaii-based

studies, turtles captured incidental to the swordfish fishery were “treated” - for lightly hooked

turtles, hooks and all gear were removed and for deeply hooked turtles the monofilament line

was cut at the wire leader. Turtles in the Azores study were typically released within 2-4 days of

capture as opposed to several hours post-capture in the Hawaii-based study. Results from the

Fall 1998 study indicated that several months after capture and release all of the turtles continued

to transmit, though one of the control turtles was transmitting only sporadically and with

insufficient to obtain location fixes (Bjorndal et al. 1999). Results from the Summer 2000 study

indicate that as of the end of October 2000, two of the four transmitters on control turtles and

five of the six transmitters on hooked turtles continued to function. Using criteria similar to the

Hawaii-based study for “successful tracks”, one of the control turtles and one of the hooked

turtles ceased transmitting within one month after release. Analyses to date have focused on

diving behavior and movement patterns and directions. A diurnal pattern in dive behavior was

evident for most hooked and control turtles, distribution of dives for hooked turtles were skewed

toward longer dives and shallower dives and hooked turtles did not show the bimodal

distributions of maximum dive depths that were characteristic of control turtles (Riewald et al.

2000). Riewald et al. (2000) opines that transmitters that provide dive profiles are necessary to

determine whether transmitter failure is due to mortality or mechanical causes and describes the

diving activity of one of the hooked turtles (still transmitting) as indicative of a dead, floating

turtle, buffeted by waves. Data analyses are ongoing by the contractor.

Post-Hooking Studies: Mediterranean

A third study approached the question of post-hooking mortality in a different way.

Aguilar et al. (1995), working in the western Mediterranean kept in captivity sea turtles that had

been incidentally captured in the Spanish longline fishery with the aim of estimating the

mortality rate of individuals with hooks still in their bodies. While the exact details of the study

are not clearly elucidated, the assumption is that turtles held in captivity for observation had

ingested a hook. It is unclear whether line attached to these hooks was removed to the maximum

extent possible, but it is reasonable to assume that this was the case. Of 38 turtles reported by

Aguilar (1995) 11 died in captivity, 6 expelled the ingested hook prior to their release (range of

days to expulsion 53-285), 15 turtles were released prior to expulsion of the hook (range of days

to release 81-123), and 6 turtles taken in 1991 remained under observation at the time the paper

was written and the fates of these turtles are unknown. Excluding the 6 turtles for whom the

fates are unknown, 34.4% died, 18.8% expelled the hook and 46.9% were released without hook

expulsion (see ranges of days in captivity above). As with the Hawaii-based study and the

Azores-based study, turtles used in this study also underwent some level of “treatment”,

including removal of trailing line (reasonably assumed though not explicitly stated), maintenance

 

22 Bjorndal, K.A., A.B. Bolten, and B. Riewald. 1999. Development and use of satellite telemetry to estimate posthooking mortality of marine turtles in the pelagic longline fisheries. NMFS-SWFSC Administrative Report H-99-

03C, Department of Zoology, University of Florida, Gainesville, 25 pp.

23 Riewald, B., A.B. Bolten, and K.A. Bjorndal. 2000. Use of satellite telemetry to estimate post-hooking behavior

and mortality of loggerhead sea turtles in the pelagic longline fishery in the Azores. NMFS-SWFSC Final Report

Order No. 40JJNF900114. Unpublished report. Department of Zoology, University of Florida, Gainesville, 28 pp.
158

in a captive environment where food was regularly provided and where predator avoidance was

not a factor. While it may be argued that turtles are further stressed under captive conditions, we

believe that the captive environment represents a less stressful environment for an injured turtle

(i.e., one that has ingested a hook). Additionally, the Aguilar study assumes that the 15 turtles

(46.9%) released before hook expulsion survived, an assumption that cannot be quantitatively

determined. One respondent to the request for comments on mortality criteria opined that

without definitive necropsies, Aguilar’s results can not be used to address post-hooking

mortality. Based on our assessment of the study, we believe that the 34.4% observed mortality

reported in the Aguilar paper is a minimal estimate of mortality for ingested hooks in the wild.

Entanglement

None of the studies discussed herein involved turtles that were only entangled, not

hooked, in longline gear. The applicability of the results of the studies reviewed above to

“entangled only” turtles is a valid question to explore. Comments on the draft strawman

suggested that the characteristics of longline monofilament make it unlikely to remain on an

“entangled only” turtle once the turtle is cut free from the gear. Data from the Hawaii longline

fishery observer program from 1994-1999 indicate that the overwhelming majority of

interactions involving hard shelled turtles involve hooking, not entanglement only (Table 1).

Hawaii longline observer records indicated that leatherback turtles are more frequently only

entangled in the gear, although nearly 75% of the time, hooking is involved (Table 1). Of the

eight leatherbacks observed “entangled only”, 25% (n=2) were dead, 37.5% (n=3) were recorded

as “okay”, and 37.5% (n=3) were recorded as “injured”.

Data from the Atlantic HMS longline fishery observer program indicate similar levels of

“entanglement only” for loggerheads and leatherbacks. The vast majority of loggerheads are

hooked while leatherbacks interact with the gear slightly differently - a greater percentage are

“entangled only” (Table 2). All of the leatherbacks observed “entangled only” were alive when

the gear was retrieved.

Table 1. Breakdown of type of gear interaction, hooked (includes lightly hooked, deeply

hooked) vs. entangled only (no hooking involved), 1994-1999 Hawaii longline observer program

(McCracken 200024).

Species Hooked Entangled Only Not Recorded TOTAL

C. caretta 143 (97.3%) 3 (2.0%) 1 (0.7%) 147

D. coriacea 29 (72.5%) 8 (20.0%) 3 (7.5%) 40

L. olivacea 32 (100%) 0 0 0

C. mydas 8 (100%) 0 0 8

 

24 McCracken, Marti L. 2000. Estimation of Sea Turtle Take and Mortality in the Hawaiian longline fisheries.

NMFS-SWFSC Administrative Report H-00-06. Unpublished Report. NMFS/SWFSC/Honolulu, HI, 29 pp
159

Table 2. Breakdown of type of gear interaction, hooked (includes lightly hooked, deeply

hooked) vs. entangled only (no hooking involved), 1999 Atlantic longline observer program.

(Data source: J. Hoey (unpublished report, 200025, summary of 1999 NMFS observer data for

HMS Atlantic longline).

Species Hooked Entangled Only Not Recorded TOTAL

C. caretta 60 (93.8%) 1 (1.6%) 3 (4.7%) 64

D. coriacea 26 (57.8%) 12 (26.7%)26 7 (15.6%) 45

Unknown 1 (33.3%) 2 (66.7%) 0 3

Conclusions and Recommendations

The Aguilar et al. (1995) results and the results of the Hawaii-based study, for mortality

from deeply ingested hooks, 34.4% and 42% respectively, are similar. Preliminary data from the

Azores study, with very limited sample sizes, indicating a 33.3% mortality from deeply ingested

hooks is also in the same range, assuming one month criteria and contractor interpretation of

diving behavior. Whether these results are corroborative or purely coincidental cannot be

qualitatively determined. The mortality range for lightly hooked and deeply hooked hard-shelled

turtles in the Hawaii-based study is 17 - 42%, based on a one-month criteria established for

successful vs. non-successful tracks.

This one-month criterion cannot be evaluated for its direct relation to mortality and the

actual “cut-off” for assuming mortality may be significantly higher or may be lower. It is

important to remember that the turtles used in all studies underwent a level of treatment (e.g.,

line and/or hook removal as well, recuperative time on deck, captive maintenance) that

undoubtedly improved their survival outlook. We believe that mortality rates in the wild, under

actual fishing conditions are likely higher than mortality rates indicated by the studies reviewed

herein. Given the available information, as well as adopting a risk-averse approach that provides

the benefit of the doubt to the species where there are gaps in the information base27, F/PR

 

25 Hoey, J. 2000. Unpublished summary of 1999 observer record comments on sea turtle interactions in the

Atlantic HMS fishery. National Marine Fisheries Service, ST, Silver Spring, Md., 9 pp.

26 Four of eight turtles may have been hooked in addition to entangled, hooking location unknown.

27 The Endangered Species Act Section 7 consultation process requires NMFS to use the best available scientific

and commercial data. The Services established criteria to ensure that the information used in the Section 7

consultation process was reliable, credible, and representative of the best available data (59 FR 34271; July 1, 1994).

To the extent practicable, NMFS must use primary and original sources of information including, but not limited to,

anecdotal, oral, and gray literature as well as published documents. If data gaps exists that would help determine the

impacts to listed species and the action agency intends to proceed with the proposed action, NMFS must proceed

with the existing information and is expected to provide the benefit of the doubt to the species concerned with

respect to such gaps in the information base (H.R. Conference Report No. 697, 96th Congress, 2nd Session 12

(1979).
160

recommends that 50% of longline interactions be classified as lethal and 50% be classified as

non-lethal. The 50% lethal classification considers the range of mortality discussed above for

lightly and deeply hooked turtles and assumes additional mortality under normal fishing

conditions, where turtles are infrequently boarded, and gear can be assumed to be left on turtles

at a greater rate than when an observer handles a turtle for a defined experiment. Observer

efforts to disentangle turtles and to remove trailing line can sometimes be described as heroic

and while we believe that some fisherpersons will undertake similar efforts, others will not. As

discussed above, most of the respondents to the NMFS request for comments/information on

post-hooking mortality characterized gear left on turtles as a serious problem, especially trailing

line which would be a significant risk to the turtle, especially when ingested hooks are involved.

While these studies are limited to hard-shelled turtles, in the absence of evidence to suggest that

interactions with leatherbacks would result in higher survival rates, we recommend that the 50%

mortality figure be applied to leatherbacks as well as hard-shelled turtles. One respondent to the

request for input on mortality criteria commented that leatherbacks are not as resilient as hardshelled turtles and that actions such as hooking, lifting from the water, and ingestion of hooks

and lines may have more damaging and long lasting impacts. Our review of the available

information does not suggest that a differential mortality estimate can be applied to lightly

hooked vs. deeply hooked vs. “entangled only” turtles at this time. While we believe that lightly

hooked turtles and “entangled only” turtles, especially those that have trailing line and hooks

removed have a greater chance of survival than deeply hooked turtles, the data do not exist to

provide for a differential apportionment. In reality, the figure may be higher than 50% for

deeply hooked turtles and lower than 50% for lightly hooked and “entangled only” turtles. In the

future, refinements to these estimates can be made if additional information is gathered and

further evidence can be provided to quantitatively define post-hooking mortality. Data collected

by observers must be standardized and of sufficient detail and description to assess and

categorize the interaction. F/PR intends to convene an expert workshop in early 2001 to further

discuss the question of sea turtle survival following interactions with longline gear and to refine,

if possible, post-interaction survival rates.

Literature Cited

Aguilar, R., J. Mas, and X. Pastor. 1995. Impact of Spanish longline fisheries on loggerhead

turtle Caretta caretta population in the western Mediterranean. U.S. Department of

Commerce NOAA Technical Memorandum NMFS-SEFSC-361:1-6.

 
161

CHAPTER 5. SUMMARY OF TAKES BY THE PELAGIC LONGLINE

FISHERY IN THE ATLANTIC OCEAN AND MEDITERRANEAN SEA

Joanne Braun-McNeill and Wayne N. Witzell

Summary of Takes

The pelagic longline fishery for tuna and swordfish incidentally captures loggerhead and

leatherback sea turtles (see Table 8 of Chapter 2 and Appendices 2 and 3). Loggerhead

juveniles, during their pelagic life stage, circumnavigate the North Atlantic via the Atlantic Gyre

and are exposed sequentially to a series of longline fisheries that primarily target swordfish and

tuna. Because leatherbacks utilize the open ocean during all life stages, they are exposed to

pelagic fishing gears throughout their entire life history. Loggerhead turtles readily ingest baited

hooks (Witzell 1999). While leatherbacks are more likely than loggerheads to become captured

through entanglement in the main and branch lines than ingestion of the baited hooks (Witzell

1984, Tobias 1991, Witzell 1999), there have been reports of leatherbacks ingesting the squid

bait used on swordfish longline gear (Skillman and Balazs 1992). According to the National

Marine Fisheries Service mandatory Pelagic Logbook Program records for the U.S. fleet,

loggerhead and leatherback CPUE was greater with vessels utilizing light sticks (targeting

swordfish) than vessels without (targeting tuna) (Witzell 1999). It has been suggested that

leatherbacks are attracted to the lightsticks used by vessels targeting swordfish, perhaps

mistaking the light sticks for bioluminescent schyozoa and then becoming entangled in the line

(Witzell 1999). This relationship, however, could not be demonstrated from observer data where

analyses indicated that sea turtle (both loggerhead and leatherback) interactions were not

positively influenced by the use of lightsticks (Hoey 199828). Most fishery-reported U.S. fleet

longline interactions with loggerhead and leatherback turtles occur from the Mid-Atlantic Bight

to areas northward. (Witzell 1999). Observer data, however, revealed greater loggerhead

interactions in the Caribbean and the Gulf of Mexico for certain years (Figs. 1 and 2).

Noteworthy was that marine turtle bycatch estimated from observer data was significantly higher

(p<0.05) than that reported in logbooks (Johnson et al. 1999) indicating that an assessment

method dependent upon the fishery’s self-reporting has limitations. According to observer

records, an estimated 7,891 loggerhead and 6,363 leatherback sea turtles were captured by the

U.S. Atlantic tuna and swordfish longline fisheries 1992-1999 of which 66 loggerhead and 88

leatherbacks were estimated to have been released dead (Table 8 of Chapter 2). Some of those

released alive may not have survived. The National Marine Fisheries Service Office of Protected

Resources recommends that 50% of longline interactions with all species of sea turtles be

classified as lethal (Table 1) and 50% be classified as non-lethal (see Chapter 4).

The U.S. longline fleet accounts for a relatively small proportion (<5-8%) of total hooks

fished in the Atlantic Ocean compared to the other nations conducting longline fishing in this

 

28 Hoey, J.J. 1998. NEFSC pelagic longline data review & analysis of gear, environmental, and operating practices

that influence pelagic longline interactions with sea turtles. Final contract report NOAA Contract -

50EANA700063. Unpublished report from National Fisheries Institute, Inc., Arlington, Va. to National Marine

Fisheries Service Northeast Regional Office, Gloucester, Mass., 32 pp.
162

area (see Chapter 1), but accounts for an average of 28% and 18% respectively, of the swordfish

and tuna landed from the North Atlantic. These other nations include Taipei, Brazil, Trinidad,

Morocco, Cyprus, Venezuela, Korea, Mexico, Cuba, U.K., Bermuda, Peoples Republic of China,

Grenada, Canada, Belize, France, and Ireland (Carocci and Majkowski 1998). In the tropics,

Brazil, Korea, Portugal, Cuba, Peoples Republic of China, Equatorial Guinea, Spain, Libya,

Cuba, Venezuela, USSR, and Portugal prosecute swordfish and tuna longline fisheries in

addition to the U.S. (Carocci and Majkowski 1998). Unfortunately, leatherback incidental

capture data for these other nations is limited. From 1987-1998, observers from the International

Observer Program in the Scotia-Fundy Region aboard longline vessels in the north Atlantic

Ocean reported the incidental capture of 25 leatherback sea turtles; the highest incidental catch of

leatherbacks was in 1995 (n=10 turtles) and 1998 (n=8 turtles) (James 2000).

Uruguayan longliners targeting tuna and swordfish in the southwest Atlantic reported

loggerhead and leatherback captures for the years 1994-1996 with a CPUE of 1.8/1000 hooks; an

estimated 98.1% were released alive (Achaval et al. 2000). Observers of the Mexican longline

tuna fishery in the Gulf of Mexico reported 2 loggerhead and 43 leatherback sea turtles

incidentally captured in 37 fishing trips (8.5% of the total effort) (Ramirez and Ania 2000). Of

the leatherbacks, 42% were caught by becoming entangled in monofilament fishing line.

Estimated incidental capture of sea turtles (both loggerheads and leatherbacks) in this fishery is 5

turtles/100 trips; mortality is estimated to be 1.6 turtles/100 trips (Ramirez and Ania 2000). In

Belize, longline fishing for sharks is reportedly catching leatherbacks (Smith et al. 1992).

Incidental capture information for the longline fisheries prosecuted in the tropics also is very

limited. The longline fishery in Antigua/Barbuda is estimated to catch 100 or more loggerhead

and leatherback sea turtles each year (Fuller et al. 1992). In St. Vincent and the Grenadines,

"some" leatherbacks also are caught by longlines (Scott and Horrocks 1993). Although there are

longline vessels in the coastal waters of Barbados, no bycatch data is available (Horrocks 1992).

Local longliners at Anegada in the British Virgin Islands have caught "some" leatherbacks

(Eckert et al. 1992, Cambers and Lima 1990, Tobias 1991).

The longline fisheries prosecuted in the Mediterranean Sea include the countries of

Algeria, Cyprus, Greece, Morocco, Spain, Italy, Malta, Taipai, Belize, Honduras, Japan, Korea,

Libya, Panama, and Portugal (Carocci and Majkowski 1998). Considerably more loggerhead

than leatherback sea turtles were reported incidentally captured in these fisheries. The Italian

longline fleet targeting swordfish reported the incidental capture of 275 loggerhead and only a

‘few’ leatherback sea turtles from 1978-1986 (De Metrio and Magalfonou 1988), 1,817

loggerheads but only 6 leatherbacks from 1978-1981 (De Metrio et al. 1983), and 650

loggerheads and no leatherbacks from 1981-1990 (Argano et al. 1992). Out of a total of 1,098

loggerheads reported captured by the Spanish longline fleet from 1991-1992, only 2 leatherbacks

were reported (Aguilar et al. 1995). Loggerheads observed captured in the Spanish swordfish

fishery during the years 1986-1995 ranged from 443-8389 (mean=4417); estimated number

captured ranged from 1,953-19,987 (mean=11,673) (Camiñas 1997). Malta's swordfish longline

fishery was estimated to catch 1,500-2,500 loggerhead but no leatherback sea turtles; an

estimated 500-600 loggerheads were killed (Gramentz 1989). From 1989-1991, 116 loggerhead
163

but no leatherback sea turtles were caught in 531 fishing trips; an estimated 70-100 loggerhead

turtles are captured annually with multiple recaptures noted (Panou et al. 199129, 199230).

Impacts of the Pelagic Longline Fishery on Sea Turtle Populations

It is very difficult to identify the impact of a fishery on sea turtle populations as the

response of the populations is based on the cumulative impacts from all sources. The

environmental baseline against which the pelagic longline fishery is being evaluated can be

found in Appendix 1 and is discussed in the Impacts sections of both the loggerhead and

leatherback stock assessment reports (Part I and Part II).

An important consideration in assessing fishery impacts on sea turtle populations is

whether or not interactions result in mortality and subsequent loss to the population. Sea turtles

that are stressed as a result of being forcibly submerged rapidly consume oxygen stores,

triggering an activation of anaerobic glycolysis, and subsequently disturbing the acid-base

balance, sometimes to lethal levels (Lutcavage and Lutz 1997). Forced submergence for

extended periods is marked with metabolic acidosis as a result of high blood lactate levels and

recovery may be as long as 20 hours (Ibid.). Additional factors such as size, activity, water

temperature, and biological and behavioral differences between species also bear directly on

metabolic rates and aerobic dive limits and will therefore also influence survivability after a gear

interaction. In addition, disease factors and hormonal status may also play a role in anoxic

survival during forced submergence. Although turtles released “unharmed” do not have visible

injuries, they may have been stressed from being caught or entangled in gear. Recent necropsy

results from the Hawaiian fishery (Work 200031) indicated that there seems to be a higher

incidence of observed drowning mortality in the Hawaiian fishery than the Atlantic fishery,

possibly to differences in fishing strategy (lines are fished deeper in the Pacific) and/or turtle

species composition (7 olive ridleys, 2 greens, 2 leatherbacks). In Atlantic observers’ records for

1992-1996, only one observed leatherback turtle out of 82 was obviously moribund and only 1

loggerhead out of 51 turtles (hard-shelled) appeared dead (Lee and Brown 1998). Work also

concluded that mortality rates using the “lightly hooked’ vs. “deeply hooked” criteria may not be

satisfactory criteria to determining probability of survival.

 

29 Panou, A., S. Moschonas, L. Tselentis, and N Voutsinas. 1991. Incidental catches of loggerhead turtles, Caretta caretta, in

swordfish long lines in the Ionian Sea, Greece. Inst. Zool. Univ. Munich, Germany. Unpublished Report. Institute of Zoology,

University of Munich, Germany, 6 pp.

30 Panou, A., G. Antypas, Y. Giannopoulos, S. Moschonas, D. Mourelatos, G. Mourelatos, Ch. Mourelatos, P. Toumazatos, L.

Tselentis, N. Voutsinas, and V. Voutsinas. 1992. Incidental catches of loggerhead turtles, Caretta caretta, in swordfish long lines

in the Ionian Sea, Greece. Unpublished Report. Institute of Zoology, University of Munich, Germany, 8 pp.

31Work, T.M. 2000. Synopsis of finding of sea turtles caught by the Hawaii-based pelagic longline fishery. Unpublished Report.

U.S. Geological Survey, National Wildlife Health Center, Hawaii Field Station, Honolulu, Hawaii, 5 pp.
164

In areas of turtle concentrations (e.g., Mediterranean Sea, Grand Banks) turtles have been

reported to have been hooked from two to eight times (Panou et al. 199132,199233, Gramentz,

1989, Argano et al. 1992, Witzell 1999, Hoey and Moore 199934). This not only compounds

mortality estimates, but it also complicates take estimates. Current bycatch estimates do not take

into consideration that an animal may be captured multiple times. Also, we do not yet have

serious injury criteria upon which an animal may be assessed for likelihood of survival and

therefore we are assuming that 50% of all animals interacting with the pelagic longlines

subsequently die as a result of that interaction, regardless of where hooked, amount of line

remaining on the animal, or the species (Table 1).

Literature Cited

Achaval, F., Y. H. Marin, and L.C. Barea. 2000. Incidental capture of turtles with pelagic

longline. U.S. Department of Commerce NOAA Technical Memorandum NMFSSEFSC-436:261.

Aguilar, R., J. Mas, and X. Pastor. 1995. Impact of Spanish swordfish longline fisheries on the

loggerhead sea turtle Caretta caretta population in the Western Mediterranean. U.S.

Department of Commerce NOAA Technical Memorandum NMFS-SEFSC-361:1-6.

Argano, R., R. Basso, M. Cocco, and G. Gerosa. 1992. Nouvi data sugli spostamenti di tartaruga

marina comune (Caretta careta) in Mediterraneo. Bollettino Musel Istitiuti Universita

Genova 56-57:137-163.

Cambers, G. and H. Lima. 1990. Leatherback turtles disappearing from the BVI. Marine Turtle

Newsletter 49:4-7.

Camiñas, J.A. 1988. Incidental captures of Caretta caretta (L.) with surface long-lines in the

western Mediterranean. Rapports et Proces-Verbaux des Reunions Conseil International

pour l’Exploration de la Mer Mediterranee 31(2): 285.

Camiñas, J.A. 1997. Capturas accidentales de tortuga boba (Caretta caretta, L. 1758) en el

Mediterráneo occidental en la pesquería de palangre de superficie de pez espada (Xiphias

gladius L.). International Commission for the Conservation of Atlantic Tunas Collective

Volume of Scientific Papers 46:446-455.

 

32Panou, A., S. Moschonas, L. Tselentis, and N Voutsinas. 1991. Incidental catches of loggerhead turtles, Caretta caretta, in

swordfish long lines in the Ionian Sea, Greece. Inst. Zool. Univ. Munich, Germany. Unpublished Report. Institute of Zoology,

University of Munich, Germany, 6 pp.

33Panou, A., G. Antypas, Y. Giannopoulos, S. Moschonas, D. Mourelatos, G. Mourelatos, Ch. Mourelatos, P. Toumazatos, L.

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34Hoey, J.J. and N. Moore. 1999. Captain’s report: multi-species catch characteristics for the U.S. Atlantic pelagic longline

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Carocci, F. and J. Majkowski. 1998. Atlas of tuna and billfish catches. CD-ROM version 1.0.

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Dermochelys coriacea L.) consequent to accidental capture in the Gulf of Taranto.

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De Metrio, G., G. Petrosino, A. Matarrese, A. Tursi, and C. Montanaro. 1983. Importance of the

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Dermochelys coriacea (L.) (Reptilia, Testudines), in the Gulf of Taranto. Oebalia IX,

N.S.: 43-53.

Eckert, K.L and T.D. Honebrink. 1992. Wider Caribbean Sea Turtle Recovery Team and

Conservation Network (WIDECAST), sea turtle recovery and action plan for St. Kitts

and Nevis. Caribbean Environmental Programme, United Nations Environment

Programme, Technical Report 17,116 pp. Kingston, Jamaica.

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and Conservation Network (WIDECAST), sea turtle recovery action plan for Antigua and

Barbuda. Caribbean Environmental Programme, United Nations Environment

Programme, Technical Report 16, 88 pp. Kingston, Jamaica.

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Horrocks, J. 1992. Wider Caribbean Sea Turtle Recovery Team and Conservation Network

(WIDECAST), sea turtle recovery action plan for Barbados. Caribbean Environmental

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Canada: evidence from an observer program, aerial surveys and a volunteer network of

fish harvesters. M.S. Thesis, Acadia University, 71 pp.

Johnson, D.R., C. Yeung, and C.A. Brown. 1999. Estimates of marine mammal and marine turtle

bycatch by the U.S. Atlantic pelagic longline fleet in 1992-1997. U.S. Department of

Commerce NOAA Technical Memorandum NMFS-SEFSC-418, 70 pp.

Lee, D.W. and C.J. Brown. 1998. SEFSC pelagic observer program data summary for 1992-

1996. U.S. Department of Commerce NOAA Technical Memorandum NMFS-SEFSC408, 21 pp.

Lutcavage, M.E. and P.L. Lutz. 1997. Diving physiology. In P.L. Lutz and J.A. Musick, eds.

The biology of sea turtles. CRC Press, Boca Raton, Florida, 432 pp.
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tuna fishery in the Gulf of Mexico. U.S. Department of Commerce NOAA Technical

Memorandum NMFS-SEFSC-436:110.

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Conservation Network (WIDECAST), sea turtle recovery action plan for St. Vincent and

the Grenadines. Caribbean Environmental Programme, United Nations Environment

Programme, Technical Report 27, 80 pp. Kingston, Jamaica.

Skillman, R.A. and G.H. Balazs. 1992. Leatherback turtle captured by ingestion of squid bait

on swordfish longline. Fishery Bulletin 90:807-808.

Smith, G.W., K.L. Eckert, and J.P. Gibson. 1992. Wider Caribbean Sea Turtle Recovery Team

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Caribbean Environmental Programme, United Nations Environment Programme,

Technical Report 18, 86 pp. Kingston, Jamaica.

Tobias, W. 1991. Turtles caught in Caribbean swordfish net fishery. Marine Turtle Newsletter

53:10-12.

Witzell, W.N. 1984. The incidental capture of sea turtles in the Atlantic U.S. Fishery

Conservation Zone by the Japanese tuna longline fleet, 1978-81. Marine Fisheries

Review 46(3):56-58.

Witzell, W.N. 1999. Distribution and relative abundance of sea turtles caught incidentally by

U.S. longline fleet in the western North Atlantic Ocean, 1992-1995. Fishery Bulletin

97:200-211.
167

Table 1. Estimated deaths of sea turtles in the U.S. Atlantic pelagic longline fishery. Mortality

estimates are 50% of the total bycatch estimates (see Chapter 2, Table 8).

Species 1992 1993 1994 1995 1996 1997 1998 1999

Loggerhead 147 209 672 1220 459 192 553 496

Green 44 16 17 20 8 0 7 0

Hawksbill 10 0 0 0 0 8 9 0

Kemp's Ridley 1 0 13 0 0 11 0 0

Unidentified 13 16 17 86 1 24 1 33

All hardshell

turtles*

214 240 719 1325 468 235 569 529

Leatherback 457 527 419 467 452 154 200 506

* Assuming all unidentified turtles are hardshell turtles.
168

Figure 1. Hardshell and leatherback turtles reported captured in the U.S. pelagic longline fleet’s

logbooks and effort reported therein.

-100 -95 -90 -85 -80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20

0

5

10

15

20

25

30

35

40

45

50

55

Pelagic Logbook 1992-1999

 effort

 hard shell turtles

-100 -95 -90 -85 -80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20

0

5

10

15

20

25

30

35

40

45

50

55

Pelagic Logbook 1992-1999

 effort

 leatherback turtles
169

Figure 2. Hardshell and leatherback sea turtle captures reported by observers in the U.S. pelagic

longline fleet and observed fishing effort.

-100 -95 -90 -85 -80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20

-10

-5

0

5

10

15

20

25

30

35

40

45

50

55

Observer Data

 

 Effort

 Hard Shell Turtles

-100 -95 -90 -85 -80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20

-10

-5

0

5

10

15

20

25

30

35

40

45

50

55

Observer Data

 

 Effort

 Leatherback Turtles
170

CHAPTER 6. IMPACT OF THE PELAGIC LONGLINE FISHERY ON

LOGGERHEAD SEA TURTLES

Sheryan P. Epperly, Melissa L. Snover, and Larry B. Crowder

The loggerhead sea turtle (Caretta caretta) occurs throughout the temperate and tropical

regions of the Atlantic, Pacific, and Indian Oceans (Dodd 1988). Its range of habitat includes

open ocean waters, continental shelves, bays, lagoons, and estuaries. Loggerheads in the

Western North Atlantic nest on high-energy beaches between the latitudes of 18° and 35° North.

At least 5 subpopulations have been identified as management units and there may be more.

Loggerheads are long-lived species which typically cannot withstand high exploitation rates,

whether intentional or incidental (Heppell et al. 1999).

The impact of the pelagic longline fishery on loggerhead sea turtle management units

must be assessed in the context of existing sources of mortality. Appendix 2 identifies known

sources of anthropogenic impacts on sea turtle populations. Relative to the identified domestic

(U.S.) sources, if we assume that 50% of all takes by the pelagic longline fishery result in

mortality (see Chapter 5, Table 1), the impact of the pelagic longline fishery on loggerhead sea

turtles, in terms of numbers of animals removed from the population, is second only to that of the

shrimp fishery. However, survival of interactions in both of these fisheries might be increased

through NMFS regulatory actions.

NMFS has taken steps to reduce the mortality of sea turtles in the shrimp fishery and is

proposing further actions. Federal regulations have required turtle excluder devices (TEDs) in

shrimp trawls at least seasonally since 1990. In early 2000 NMFS published an advance notice

of proposed rulemaking (65 FR 17852-17854, April 5, 2000). The agency is proposing technical

changes to the requirements for TEDs, including modifying the size of the escape opening to

allow the larger benthic immature and adult turtles to escape. Epperly and Teas (199935)

determined that the body depth of loggerhead turtles is exceeding the minimum required TED

height openings before the turtles can reach maturity. Turtles with deeper bodies than the height

opening cannot escape; hence existing TEDs likely only are beneficial to the small benthic

immature stage of loggerheads.

Heppell et al. (in press) constructed matrix projection models to assess the impacts of

different TED effectiveness scenarios on population growth. They looked at 2 models, one using

parameters from previous matrix models and one using parameters consistent with new

information about growth rates of loggerheads. They initiated the model runs with a population

declining at a rate of 5% per year. In the model runs where only small turtles benefit from the

use of TEDs, the rate of decline in population growth rates slowed, however, the trend was still

negative. Only when small and large benthic turtles both benefited with decreases in mortality

did the population trend become positive. Including reductions in mortality for adult sized

animals increased population growth rates further.

 

35 Epperly, S.P. and W.G. Teas. 1999. Evaluation of TED opening dimensions relative to size of turtles stranding in

the Western North Atlantic. Unpublished Report. National Marine Fisheries Service Southeast Fisheries Science

Center Contribution PRD-98/99-08, 31 pp., Miami, Fla.
171

In Part I we revised the models of Heppell et al. (in press) with new vital rate information

and looked at 4 models representing different possible stage durations and lengths of time to

maturity. We initiated our model runs at three different population growth rates, at declines of

5% and 3% per year and a stable population at 0% change per year. We also looked at three

different possible sex ratios where the proportion of female offspring were 0.35, 0.50 and 0.80.

See Part I for model results.

Through the current reinitiation of consultation on the pelagic longline fishery, NMFS

may be able to identify reasonable and prudent alternatives that would effect some proportional

reduction in mortality of sea turtles by the pelagic longline fishery. Some measures to reduce

mortality already are in place and others are under consideration (see Chapter 8). Effective early

2001 all Atlantic pelagic longline vessels issued Federal Highly Migratory Species permits must

carry on board dipnets and line clippers and must comply with requirements for the use for these

and for the handling of incidentally caught sea turtles (65 FR 60889-60892, October 13, 2000).

This measure was designed to reduce the mortality rate of captured sea turtles by providing

devices to facilitate the removal of hooks and line from the turtles.

We examined the effect of two possible regulations: (1) the expanded TED regulations

and (2) unidentified regulations that would effect some proportional reduction in mortality by the

pelagic longline fishery. These actions would be affecting two different life stages of

loggerheads. The TED regulations would positively affect survival in the benthic immature and

adult stages. A decrease in the mortality due to the pelagic longline fishery would positively

affect survival of the pelagic immature stage.

These regulatory effects are evaluated relative to the first of the recovery goals set for the

species (NMFS and USFWS 1991):

1. The adult female population in Florida is increasing and in North Carolina, South

Carolina, and Georgia, it has returned to pre-listing levels (N.C.-800 nests/season;

S.C.=10,000 nests/season; Ga.=2,000 nests/season). The above conditions must be met

with data from standardized surveys which will continue for at least 5 years after

delisting.

2. At least 25 percent (560 km) of all available nesting beaches (2,240 km) are in public

ownership, distributed over the entire nesting range and encompassing at least 50 percent

of the nesting activity within each State.

3. All priority one tasks have been successfully implemented.

We evaluate the population trajectories of the annual numbers of nesting females under

different management scenarios: (1) expanded TED regulations in the absence of any regulation

of the pelagic longline fishery, (2) regulation of the pelagic longline fishery alone to effect an

increase in survival of pelagic animals, and (3) the combination of both regulations. The number

of nesting females can be related to the number of nests identified in the recovery goal by

assuming that a female, on average, lays 4.1 clutches of eggs/season (Murphy and Hopkins
172

198436). In 1990 an estimated 7,737 nests were observed in the northern subpopulation,

translating to 1,887 nesting females (TEWG 2000). Thus, all the model runs begin with an adult

female population size of 2,000 animals in 1990. At the time the recovery plan was written

management units had not been identified. The beaches of North Carolina, South Carolina, and

Georgia roughly approximate the nesting range of the northern subpopulation but the

subpopulation’s nesting range also includes northern Florida. From 1990 to 1998, the

contribution of northern Florida to total nest numbers for the northern subpopulation averaged

21% (TEWG 2000). Thus the recovery goal of 12,800 nests/season for North Carolina, South

Carolina and Georgia translates to an estimated 15,488 nests/season for the northern

subpopulation, corresponding to 3,777 nesting females per season.

In Part I, we considered 4 models, each based on different stage lengths and time to

maturity. We found that for the combination of parameters in model 2, the pelagic survival rates

were unreasonably high, 0.91 and 0.99, and not likely to be representative of actual annual

pelagic stage survival rates for loggerheads. Hence, we consider only models 1, 3, and 4 in this

impact assessment. For each of the 3 models, we looked at three possible initial population

growth rates for the northern subpopulation, -5% per year (suggested for South Carolina trends

in TEWG (1998) and used in models by Heppell et al. (in press), -3% per year (estimated for

Little Cumberland Island, Georgia trends by Frazer (1983) and used in models by Crouse et al.

(1987) and Crowder et al. (1994) and 0% per year (suggested by a preliminary meta-analysis of

nesting trends (see Appendix 1 of this document for the revised analyses)). For this impact

assessment we again consider all three possible population growth rates as there is evidence for

each of them and we cannot eliminate any one of them unequivocally.

Within each of these population growth rates we considered 3 possible sex ratios. From

our analysis of sex ratios of the individual subpopulations (Part I), we estimated 35% female

hatchlings are produced in the northern nesting subpopulation and 80% in the south Florida

subpopulation. To be consistent with the historical models we also consider a 50% production of

female offspring. In summary there are 27 different model scenarios: 3 different stage durations

(Models 1, 3, and 4) (see Tables 11-14 in Part I), 3 different pre-TED regulations population

growth rates, and 3 different sex ratios.

Expanded TED Regulations

We first looked at the effect of expanded TED regulations on population growth rates.

The models were initiated with a population at stable age distribution for annual survival rates

incorporating a 30% reduction in mortality for small benthic turtles and subsequently run with

annual survival rates incorporating 30% reductions in mortality for large benthic juveniles and

adults. The models run at a sex ratio of 0.5 are most comparable to Heppell et al. (in press) (Fig.

1). Heppell et al. (in press) found that an initial population growth rate of –5% would achieve

positive population growth rates with similar mortality reductions. We found that while positive

growth rates are achieved for the model representative of historical population parameters

(Model 1), positive growth rates are not achieved for the new population vital rates (Models 3

 

36 Murphy, T.M. and S.R. Hopkins. 1984. Aerial and ground surveys of marine turtle nesting beaches in the

southeast region, U.S. Final report to National Marine Fisheries Service Southeast Fisheries Science Center.

Unpublished Report. South Carolina Marine Resources Department, Charleston, S.C., 52 pp.
173

and 4). Population growth rates are positive for all models at the remaining two initial

population growth rates (-3% and 0%, Fig. 1)

At a sex ratio of 0.35, which results in a fecundity value that is likely more representative

of the northern subpopulation, a similar trend is seen though proportionately reduced and

populations only achieve stable growth (0%) when the initial population is declining at –3% per

year (Fig. 2). When the production of female offspring increases to 80%, the expanded TED

regulations (% change in pelagic survival equals 0) result in increasing population trends in all

cases except for Model 4, which has the longest stage durations, at a population that is initially

declining at a rate of –5% per year (Fig. 3). Population trajectories are plotted in Figs. 5-7, 9-11,

and 13-15 as a 0% change in pelagic survival. The initial increases in nesting females in each of

these plots results from increased survival of adults and increased numbers of large benthic

juveniles reaching maturity. Once the pulse of large benthic juveniles has aged through to adults

(length of time equal to the duration of the large benthic juvenile stage), the numbers of nesting

females levels out or begins to decline depending on the population growth rate. Other shifts

will occur once the offspring of the increased number of adults reach maturity, however this can

only be seen in the plots for Model 1 (Fig. 5, 9, and 13) as time series were not run long enough

for Models 3 and 4 (Fig. 6, 7, 10, 11, 14, and 15).

Changes in Pelagic Juvenile Annual Survival Rates

We next examined how a potential regulation of the pelagic longline fishery to affect an

increase in survival of pelagic animals would impact population growth rates. For the same 27

model scenarios described above, we increased and decreased pelagic juvenile annual survival

rates by 5 and 10%. These models were again initialized with survival rates representing a 30%

reduction in mortality in the small benthic juvenile stage.

At a sex ratio of 0.35 and a population initially declining at a rate of 5% per year,

reductions in pelagic mortality rates alone are not enough achieve increasing population growth

rates with the exception of a 10% increase in survival in Model 1 (Figs. 16 and 17). If the initial

population is stable, increases in pelagic juvenile survival rates proportionately increase annual

population growth rates beyond that affected by reduced mortality in small benthic juveniles

alone (represented by the 0% annual population growth rate). However, decreases in pelagic

juvenile survival reduce or negate the benefits of increased small benthic juvenile survival and at

a 10% reduction in pelagic juvenile survival, populations are in decline (Fig. 16). The

population trajectories for the numbers of nesting females associated with each population

growth rate in Fig. 16 are plotted in Figs. 17-19. As the trajectories consider adults only, no

benefits or negative impacts of changes in juvenile survival rates are seen until the effected

stages reach maturity, or the sum of the lengths of the small and large benthic juvenile stages.

As discussed in the above section, the effects of the increased/decreased numbers of offspring

from the changes in numbers of nesting females result in another pulse in the population a

generation later.

Similar but proportionately more positive trends are seen when you increase fecundity

with sex ratios of 0.50 and 0.80 (Figs. 20-27). When populations are exhibiting only slight

increases in growth rates (less than about 0.5%), decreases in pelagic juvenile survival rates
174

result in decreasing population growth rates. Conversely, when populations are slightly

decreasing as in Fig. 20, λ=0.97, Model 3 and Fig. 24, λ=0.97, and Model 4, increases in pelagic

juvenile annual survival rates achieve positive population growth rates.

Combination of Expanded TED Regulations and Changes in Pelagic Juvenile Annual

Survival

To look at the combination of both regulations, we initialized the models in the same

manner described above and ran them with 30% reductions in mortality for large benthic

juveniles and adults with pelagic juvenile survival rates increased and decreased at 5 and 10%.

At a sex ratio of 0.35, the highest survival rate scenario (+10% for pelagic juvenile

survival) decreased the –5% per year population decline to almost 0% for the models

incorporating updated stage durations (3 and 4) (Figs. 4-7) and resulted in increasing trends for

sex ratios of 0.50 and 0.80 (Figs. 8-15). At initial population declines of 3% per year, expanded

TED regulations alone achieve 0 population growth and the additional benefit of increased

pelagic juvenile survival result in positive trends (Figs. 4-7). When the initial population is

stable, increases in survival for all benthic stages maintain positive population growth rates even

at decreases in pelagic juvenile survival of 10% for all sex ratios (Figs. 4-15).

Population Recovery

Because of the uncertainties involved in parameterizing these models, the population

trajectory plots should not be used to quantitatively assess population size (Heppell et al. in

press). However, in a general analysis of the plots it is apparent that some of the model

combinations for the 0.35 sex ratio will not achieve the recovery goals of 3,777 nesting females

per year in the time span modeled (NMFS and USFWS 1991). We believe that the stage

durations of Models 3 and 4 are most representative of loggerhead growth rates for the northern

subpopulation. For initial declining population growth rates of 5% and 3%, none of the

regulation scenarios result in recovered populations within 25 years (Figs. 6, 7, 18 and 19) for

these two models. This is due to the long benthic juveniles stages of these two models (24 and

33 years respectively), and the fact that there is a time lag before the benefits of increased

juvenile survival results in increasing number of nesting females on the beach. The scenarios

with increased survival for all in-water life-stages result in much more rapid recoveries (Figs. 6

and 7 compared to Figs. 18 and 19). If the populations were stable prior to the 1990 TED

regulations, then the populations represented by Models 3 and 4 at a 0.35 sex ratios appear to be

recovering, again at a much faster rate if all in-water stages have increased survivorship. (Fig. 6,

7, 18, 19). Decreased pelagic juvenile survival neutralizes or negates the recovery.

Literature Cited

Crouse, D.T., L.B. Crowder, H. Caswell. 1987. A stage-based population model for loggerhead

sea turtles and implications for conservation. Ecology 68: 1412-1423.
175

Crowder, L.B., D.T. Crouse, S.S. Heppell, and T.H. Martin. 1994. Predicting the impact of turtle

excluder devices on loggerhead sea turtle populations. Ecological Applications 4: 437-

445.

Dodd, C.K., Jr. 1988. Synopsis of the biological data on the loggerhead sea turtle Caretta

caretta (Linnaeus 1758). U.S. Department of the Interior, Fish and Wildlife Service

Biological Report 88(14), 110 pp.

Frazer, N.B. 1983. Demography and life history of the Atlantic loggerhead sea turtle (Caretta

caretta). Ph.D. Dissertation. University of Georgia.

Hempell,S.S., L.B. Crowder, D.T. Crouse, S.P.Epperly, and N.B. Frazer. in press. Population

models for Atlantic loggerheads; past, present and future. In A. Bolton and B.

Witherington, editors, Synopsis of the Biology and Conservation of Loggerhead Sea

Turtles, Smithsonian Institution Press.

Heppell, S.S., L.B. Crowder, and T.R. Menzel. 1999. Life table analysis of long-lived marine

species with implications for conservation and management. American Fisheries Society

Symposium 23:137-148.

National Marine Fisheries Service and U.S. Fish and Wildlife Service. 1991. Recovery plan for

U.S. population of loggerhead turtles. National Marine Fisheries Service, Silver Spring,

Md., 64 pp.

Richardson, J.I. and T.H. Richardson. 1982. An experimental population model for the

loggerhead sea turtle (Caretta caretta), pp. 165-174. In K.A. Bjorndal, ed. Biology and

Conservation of Sea Turtles. Smithsonian Institution Press, Washington, D.C.

Turtle Expert Working Group. 1998. An assessment of the Kemp’s ridley (Lepidochelys kempii)

and loggerhead (Caretta caretta) sea turtle populations in the Western North Atlantic.

U.S. Department of Commerce NOAA Technical Memorandum NMFS-SEFSC-409,

96pp.

Turtle Expert Working Group. 2000. Assessment update for the Kemp’s ridley and loggerhead

sea turtle populations in the Western North Atlantic. U.S. Department of Commerce

NOAA Technical Memorandum NMFS-SEFSC-444, 115 pp.
176

Figures 1-3. Annual population growth rates for expanded TED regulations that reduce mortality in all

benthic stages by 30%. Models were based on pre-1990 population growth rates of –5%, -3% and 0%

(equivalent to λ values of 0.95, 0.97 and 1.0). Proportion of female offspring is 050 for Figure 1, 0.35 for

Figure 2 and 0.80 for Figure3.

Figure 1

Decreasing Mortality by 30% for All Benthic 

Stages; Sex Ratio = 0.50

-0.02

0

0.02

0.04

0.06

0.08

0.1

Model 1 Model 3 Model 4

Annual Population Growth 

Rate

0.95

0.97

1

Figure 2

Decreasing Mortality by 30% for All Benthic 

Stages; Sex Ratio = 0.35

0.039 0 0

-0.04

-0.02

0

0.02

0.04

0.06

0.08

Model 1 Model 3 Model 4

Annual Population Growth 

Rate

0.95

0.97

1

Figure 3

Decreasing Mortality by 30% for All Benthic Stages; 

Sex Ratio = 0.80

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.12

Annual Population Growth Rate

Model 1 Model 3 Model 4

0.95

0.97

1
177

Figure 4. Annual population growth rates for expanded TED regulations that reduce mortality in all

benthic stages by 30%. The 0% value represents the baseline pelagic juvenile survival rate calculated in

Part I. The other values represent percent increases or decreases in pelagic juvenile survival rates from

baseline (combination of pelagic longline fishery regulations and expanded TED regulations). Models

were based on pre-1990 population growth rates of –5%, -3% and 0% (equivalent to λ values of 0.95,

0.97 and 1.0). Proportion of female offspring is 0.35.

Initial Lambda = 0.95; Sex Ratio = 0.35; TED effect for all benthic 

stages

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

Annual Population Growth Rate

Model 1 Model 3 Model 4

+10%

+5%

0%

-5%

-10%

Initial Lambda = 0.97; Sex Ratio = 0.35; TED effect for all benthic 

stages

-0.04

-0.02

0

0.02

0.04

0.06

0.08

Annual Population Growth Rate

Model 1 Model 3 Model 4

+10%

+5%

0%

-5%

-10%

Initial Lambda = 1.00; Sex Ratio = 0.35; TED effect for all benthic 

stages

0

0.02

0.04

0.06

0.08

0.1

0.12

Annual Population Growth Rate

Model 1 Model 3 Model 4

+10%

+5%

0%

-5%

-10%
178

Figure 5. The population trajectories for expanded TED regulations that reduce mortality in all benthic

stages by 30% under the Model 1 scenario. The 0% value represents the baseline pelagic juvenile

survival rate calculated in Part I. The other values represent percent increases or decreases in pelagic

juvenile survival rates from baseline (combination of pelagic longline fishery regulations and expanded

TED regulations). Models were based on pre-1990 population growth rates of –5%, -3% and 0%

(equivalent to λ values of 0.95, 0.97 and 1.0). Proportion of female offspring is 0.35.

Model 1; Initial Lambda = 0.95; Sex Ratio = 0.35; TED 

effect for all benthic stages

0

2000

4000

6000

8000

10000

12000

0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 1; Initial Lambda = 0.97; Sex Ratio = 0.35; TED 

effect for all benthic stages

0

5000

10000

15000

20000

25000

30000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 1; Initial Lambda = 1.00; Sex Ratio = 0.35; TED 

effect for all benthic stages

0

20000

40000

60000

80000

100000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %
179

Figure 6. The population trajectories for expanded TED regulations that reduce mortality in all benthic

stages by 30% under the Model 3 scenario. The 0% value represents the baseline pelagic juvenile

survival rate calculated in Part I. The other values represent percent increases or decreases in pelagic

juvenile survival rates from baseline (combination of pelagic longline fishery regulations and expanded

TED regulations). Models were based on pre-1990 population growth rates of –5%, -3% and 0%

(equivalent to λ values of 0.95, 0.97 and 1.0). Proportion of female offspring is 0.35.

Model 3; Initial Lambda = 0.95; Sex Ratio = 0.35; TED 

effect for all benthic stages

0

500

1000

1500

2000

2500

0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 3; Initial Lambda = 0.97; Sex Ratio = 0.35; TED 

effect for all benthic stages

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 3; Initial Lambda = 1.00; Sex Ratio = 0.35; TED 

effect for all benthic stages

0

4000

8000

12000

16000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %
180

Figure 7. The population trajectories for expanded TED regulations that reduce mortality in all benthic

stages by 30% under the Model 4 scenario. The 0% value represents the baseline pelagic juvenile survival

rate calculated in Part I. The other values represent percent increases or decreases in pelagic juvenile

survival rates from baseline (combination of pelagic longline fishery regulations and expanded TED

regulations). Models were based on pre-1990 population growth rates of –5%, -3% and 0% (equivalent to

λ values of 0.95, 0.97 and 1.0). Proportion of female offspring is 0.35.

Model 4; Initial Lambda = 0.95; Sex Ratio = 0.35; TED 

effect for all benthic stages

0

500

1000

1500

2000

2500

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 4; Initial Lambda = 0.97; Sex Ratio = 0.35; TED 

effect for all benthic stages

0

1000

2000

3000

4000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 4; Initial Lambda = 1.00; Sex Ratio = 0.35; TED 

effect for all benthic stages

0

2000

4000

6000

8000

10000

12000

14000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %
181

Figure 8. Annual population growth rates for expanded TED regulations that reduce mortality in all

benthic stages by 30%. The 0% value represents the baseline pelagic juvenile survival rate calculated in

Part I. The other values represent percent increases or decreases in pelagic juvenile survival rates from

baseline (combination of pelagic longline fishery regulations and expanded TED regulations). Models

were based on pre-1990 population growth rates of –5%, -3% and 0% (equivalent to λ values of 0.95,

0.97 and 1.0). Proportion of female offspring is 0.50.

Initial Lambda = 0.95; Sex Ratio = 0.50; TED effect for all 

benthic juveniles

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Model 1 Model 3 Model 4

+10%

+5%

0 %

-5%

-10%

Initial Lambda = 0.97; Sex Ratio = 0.50; TED effect for all 

benthic juveniles

-0.02

0

0.02

0.04

0.06

0.08

0.1

Model 1 Model 3 Model 4

+10%

+5%

0 %

-5%

-10%

Initial Lambda = 1.00; Sex Ratio = 0.50; TED effect for all 

benthic juveniles

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

Model 1 Model 3 Model 4

+10%

+5%

0 %

-5%

-10%
182

Figure 9. The population trajectories for expanded TED regulations that reduce mortality in all benthic

stages by 30% under the Model 1 scenario. The 0% value represents the baseline pelagic juvenile

survival rate calculated in Part I. The other values represent percent increases or decreases in pelagic

juvenile survival rates from baseline (combination of pelagic longline fishery regulations and expanded

TED regulations). Models were based on pre-1990 population growth rates of –5%, -3% and 0%

(equivalent to λ values of 0.95, 0.97 and 1.0). Proportion of female offspring is 0.50.

Model 1; Initial Lambda = 0.95; Sex Ratio = 0.50; TED effect 

for all benthic juveniles

0

4000

8000

12000

16000

20000

0 10 20 30 40 50

Time (yrs.)

Number of Nesting Females

+10%

+5%

-5%

-10%

0%

Model 1; Initial Lambda = 0.97; Sex Ratio = 0.50; TED 

effect for all benthic juveniles

0

8000

16000

24000

32000

40000

48000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 1; Initial Lambda = 1.00; Sex Ratio = 0.50; TED effect 

for all benthic juveniles

0

20000

40000

60000

80000

100000

120000

140000

160000

180000

0 10 20 30 40 50

Time (yrs.)

Number of Nesting Females

+10%

+5%

-5%

-10%

0%
183

Figure 10. The population trajectories for expanded TED regulations that reduce mortality in all benthic

stages by 30% under the Model 3 scenario. The 0% value represents the baseline pelagic juvenile

survival rate calculated in Part I. The other values represent percent increases or decreases in pelagic

juvenile survival rates from baseline (combination of pelagic longline fishery regulations and

expanded TED regulations). Models were based on pre-1990 population growth rates of –5%, -3% and

0% (equivalent to λ values of 0.95, 0.97 and 1.0). Proportion of female offspring is 0.50.

Model 3; Initial Lambda = 0.95; Sex Ratio = 0.50; TED 

effect for all benthic juveniles

0

500

1000

1500

2000

2500

3000

3500

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 3; Initial Lambda = 0.97; Sex Ratio = 0.50; TED 

effect for all benthic juveniles

0

1000

2000

3000

4000

5000

6000

7000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 3; Initial Lambda = 1.00; Sex Ratio = 0.50; TED effect 

for all benthic juveniles

0

4000

8000

12000

16000

20000

24000

0 10 20 30 40 50

Time (yrs.)

Number of Nesting Females

+10%

+5%

-5%

-10%

0%
184

Figure 11. The population trajectories for expanded TED regulations that reduce mortality in all benthic

stages by 30% under the Model 4 scenario. The 0% value represents the baseline pelagic juvenile

survival rate calculated in Part I. The other values represent percent increases or decreases in pelagic

juvenile survival rates from baseline (combination of pelagic longline fishery regulations and expanded

TED regulations). Models were based on pre-1990 population growth rates of –5%, -3% and 0%

(equivalent to λ values of 0.95, 0.97 and 1.0). Proportion of female offspring is 0.50.

Model 4; Initial Lambda = 0.95; Sex Ratio = 0.50; TED effect 

for all benthic juveniles

0

500

1000

1500

2000

2500

0 10 20 30 40 50

Time (yrs.)

Number of Nesting Females

+10%

+5%

-5%

-10%

0%

Model 4; Initial Lambda = 0.97; Sex Ratio = 0.50; TED 

effect for all benthic juveniles

0

1000

2000

3000

4000

5000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 4; Initial Lambda = 1.0; Sex Ratio = 0.50; TED effect 

for all benthic juveniles

0

3000

6000

9000

12000

15000

18000

0 10 20 30 40 50

Time (yrs.)

Number of Nesting Females

+10%

+5%

-5%

-10%

0%
185

Figure 12. Annual population growth rates for expanded TED regulations that reduce mortality in all

benthic stages by 30%. The 0% value represents the baseline pelagic juvenile survival rate calculated in

Part I. The other values represent percent increases or decreases in pelagic juvenile survival rates from

baseline (combination of pelagic longline fishery regulations and expanded TED regulations). Models

were based on pre-1990 population growth rates of –5%, -3% and 0% (equivalent to λ values of 0.95,

0.97 and 1.0). Proportion of female offspring is 0.80.

Initial Lambda = 0.95; Sex Ratio = 0.80; TED Effects for 

all benthic stages

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

Model 1 Model 3 Model 4

+10%

+5%

0 %

-5%

-10%

Initial Lambda = 0.97; Sex Ratio = 0.80; TED Effects for 

all benthic stages

0

0.02

0.04

0.06

0.08

0.1

0.12

Model 1 Model 3 Model 4

+10%

+5%

0 %

-5%

-10%

Initial Lambda = 1.0; Sex Ratio = 0.80; TED Effects for 

all benthic stages

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

Model 1 Model 3 Model 4

+10%

+5%

0 %

-5%

-10%
186

Figure 13. The population trajectories for expanded TED regulations that reduce mortality in all benthic

stages by 30% under the Model 1 scenario. The 0% value represents the baseline pelagic juvenile survival

rate calculated in Part I. The other values represent percent increases or decreases in pelagic juvenile

survival rates from baseline (combination of pelagic longline fishery regulations and expanded TED

regulations). Models were based on pre-1990 population growth rates of –5%, -3% and 0% (equivalent to

λ values of 0.95, 0.97 and 1.0). Proportion of female offspring is 0.80.

Model 1; Initial Lambda = 0.95; Sex Ratio = 0.80; TED 

Effects for all benthic stages

0

10000

20000

30000

40000

50000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 1; Initial Lambda = 0.97; Sex Ratio = 0.80; TED 

Effects for all benthic stages

-10000

10000

30000

50000

70000

90000

110000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 1; Initial Lambda = 1.00; Sex Ratio = 0.80; TED 

Effects for all benthic stages

0

40000

80000

120000

160000

200000

240000

280000

320000

360000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %
187

Figure 14. The population trajectories for expanded TED regulations that reduce mortality in all benthic

stages by 30% under the Model 3 scenario. The 0% value represents the baseline pelagic juvenile survival

rate calculated in Part I. The other values represent percent increases or decreases in pelagic juvenile

survival rates from baseline (combination of pelagic longline fishery regulations and expanded TED

regulations). Models were based on pre-1990 population growth rates of –5%, -3% and 0% (equivalent to

λ values of 0.95, 0.97 and 1.0). Proportion of female offspring is 0.80.

Model 3; Initial Lambda = 0.95; Sex Ratio = 0.80; TED 

Effects for all benthic stages

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

5500

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 3; Initial Lambda = 0.97; Sex Ratio = 0.80; TED 

Effects for all benthic stages

0

2000

4000

6000

8000

10000

12000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 3; Initial Lambda = 1.00; Sex Ratio = 0.80; TED 

Effects for all benthic stages

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %
188

Figure 15. The population trajectories for expanded TED regulations that reduce mortality in all benthic

stages by 30% under the Model 4 scenario. The 0% value represents the baseline pelagic juvenile survival

rate calculated in Part I. The other values represent percent increases or decreases in pelagic juvenile

survival rates from baseline (combination of pelagic longline fishery regulations and expanded TED

regulations). Models were based on pre-1990 population growth rates of –5%, -3% and 0% (equivalent to

λ values of 0.95, 0.97 and 1.0). Proportion of female offspring is 0.80.

Model 4; Initial Lambda = 0.95; Sex Ratio = 0.80; TED 

Effects for all benthic stages

0

500

1000

1500

2000

2500

3000

3500

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 4; Initial Lambda = 0.97; Sex Ratio = 0.80; TED 

Effects for all benthic stages

0

2000

4000

6000

8000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %

Model 4; Initial Lambda = 1.00; Sex Ratio = 0.80; TED 

Effects for all benthic stages

0

4000

8000

12000

16000

20000

24000

28000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0 %
189

Figure 16. Annual population growth rates increases and decreases in the annual pelagic juvenile survival

rate (-10%, -5%, 0%, +5% and +10%) and a 30% decrease in mortality for small benthic juveniles only

(no expanded TED regulations). Models were based on pre-1990 population growth rates of –5%, -3%

and 0% (equivalent to λ values of 0.95, 0.97 and 1.0). Proportion of female offspring is 0.35.

Initial Lambda = 0.95; Sex Ratio = 0.35

-0.07

-0.06

-0.05

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

Model 1 Model 3 Model 4

+10%

+5%

0%

-5%

-10%

Initial Lambda = 0.97; Sex Ratio = 0.35

-0.05

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

Model 1 Model 3 Model 4

+10%

+5%

0%

-5%

-10%

Initial Lambda = 1.00; Sex Ratio = 0.35

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Model 1 Model 3 Model 4

+10%

+5%

0%

-5%

-10%
190

Figure 17. The population trajectories for the Model 1 scenario resulting from increases and decreases in

the annual pelagic juvenile survival rate (-10%, -5%, 0%, +5% and +10%) and a 30% decrease in

mortality for small benthic juveniles only (no expanded TED regulations). Models were based on pre1990 population growth rates of –5%, -3% and 0% (equivalent to λ values of 0.95, 0.97 and 1.0).

Proportion of female offspring is 0.35.

Model 1; Initial Lambda = 0.95; Sex Ratio = 0.35

0

500

1000

1500

2000

2500

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 1; Initial Lambda = 0.97; Sex Ratio = 0.35

0

2000

4000

6000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 1; Initial Lambda = 1.00; Sex Ratio = 0.35

0

4000

8000

12000

16000

20000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%
191

Figure 18. The population trajectories for the Model 3 scenario resulting from increases and decreases in

the annual pelagic juvenile survival rate (-10%, -5%, 0%, +5% and +10%) and a 30% decrease in

mortality for small benthic juveniles only (no expanded TED regulations). Models were based on pre1990 population growth rates of –5%, -3% and 0% (equivalent to λ values of 0.95, 0.97 and 1.0).

Proportion of female offspring is 0.35.

Model 3; Initial Lambda = 0.95; Sex Ratio = 0.35

0

500

1000

1500

2000

2500

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 3; Initial Lambda = 0.97; Sex Ratio = 0.35

0

500

1000

1500

2000

2500

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 3; Initial Lambda = 1.00; Sex Ratio = 0.35

0

2000

4000

6000

8000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%
192

Figure 19. The population trajectories for the Model 4 scenario resulting from increases and decreases in

the annual pelagic juvenile survival rate (-10%, -5%, 0%, +5% and +10%) and a 30% decrease in

mortality for small benthic juveniles only (no expanded TED regulations). Models were based on pre1990 population growth rates of –5%, -3% and 0% (equivalent to λ values of 0.95, 0.97 and 1.0).

Proportion of female offspring is 0.35.

Model 4; Initial Lambda = 0.95; Sex Ratio = 0.35

0

500

1000

1500

2000

2500

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 4; Initial Lambda = 0.97; Sex Ratio = 0.35

0

500

1000

1500

2000

2500

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 4; Initial Lambda = 1.00; Sex Ratio = 0.35

0

2000

4000

6000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%
193

Figure 20. Annual population growth rates increases and decreases in the annual pelagic juvenile survival

rate (-10%, -5%, 0%, +5% and +10%) and a 30% decrease in mortality for small benthic juveniles only

(no expanded TED regulations). Models were based on pre-1990 population growth rates of –5%, -3%

and 0% (equivalent to λ values of 0.95, 0.97 and 1.0). Proportion of female offspring is 0.50.

Initial Lambda = 0.95; Sex Ratio = 0.50

-0.06

-0.05

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

Model 1 Model 3 Model 4

+10%

+5%

0%

-5%

-10%

Initial Lambda = 0.97; Sex Ratio = 0.50

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05

0.06

Model 1 Model 3 Model 4

+10%

+5%

0%

-5%

-10%

Initial Lambda = 1.00; Sex Ratio = 0.50

-0.01

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

Model 1 Model 3 Model 4

+10%

+5%

0%

-5%

-10%
194

Figure 21. The population trajectories for the Model 1 scenario resulting from increases and decreases in

the annual pelagic juvenile survival rate (-10%, -5%, 0%, +5% and +10%) and a 30% decrease in

mortality for small benthic juveniles only (no expanded TED regulations). Models were based on pre1990 population growth rates of –5%, -3% and 0% (equivalent to λ values of 0.95, 0.97 and 1.0).

Proportion of female offspring is 0.50.

Model 1; Initial Lambda = 0.95; Sex Ratio = 0.50

0

1000

2000

3000

4000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 1; Initial Lambda = 0.97; Sex Ratio = 0.50

0

2000

4000

6000

8000

10000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 1; Initial Lambda = 1.00; Sex Ratio = 0.50

0

10000

20000

30000

40000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%
195

Figure 22. The population trajectories for the Model 3 scenario resulting from increases and decreases in

the annual pelagic juvenile survival rate (-10%, -5%, 0%, +5% and +10%) and a 30% decrease in

mortality for small benthic juveniles only (no expanded TED regulations). Models were based on pre1990 population growth rates of –5%, -3% and 0% (equivalent to λ values of 0.95, 0.97 and 1.0).

Proportion of female offspring is 0.50.

Model 3; Initial Lambda = 0.95; Sex Ratio = 0.50

0

500

1000

1500

2000

2500

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 3; Initial Lambda = 0.97; Sex Ratio = 0.50

0

500

1000

1500

2000

2500

3000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 3; Initial Lambda = 1.00; Sex Ratio = 0.50

0

2000

4000

6000

8000

10000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%
196

Figure 23. The population trajectories for the Model 4 scenario resulting from increases and decreases in

the annual pelagic juvenile survival rate (-10%, -5%, 0%, +5% and +10%) and a 30% decrease in

mortality for small benthic juveniles only (no expanded TED regulations). Models were based on pre1990 population growth rates of –5%, -3% and 0% (equivalent to λ values of 0.95, 0.97 and 1.0).

Proportion of female offspring is 0.50.

Model 4; Initial Lambda = 0.95; Sex Ratio = 0.50

0

500

1000

1500

2000

2500

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 4; Initial Lambda = 0.97; Sex Ratio = 0.50

0

500

1000

1500

2000

2500

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 4; Initial Lambda = 1.00; Sex Ratio = 0.50

0

2000

4000

6000

8000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%
197

Figure 24. Annual population growth rates increases and decreases in the annual pelagic juvenile survival

rate (-10%, -5%, 0%, +5% and +10%) and a 30% decrease in mortality for small benthic juveniles only

(no expanded TED regulations). Models were based on pre-1990 population growth rates of –5%, -3%

and 0% (equivalent to λ values of 0.95, 0.97 and 1.0). Proportion of female offspring is 0.80.

Initial Lambda = 0.95; Sex Ratio = 0.80

-0.05

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05

Model 1 Model 3 Model 4

+10%

+5%

0%

-5%

-10%

Initial Lambda = 0.97; Sex Ratio = 0.80

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

Model 1 Model 3 Model 4

+10%

+5%

0%

-5%

-10%

Initial Lambda = 1.0; Sex Ratio = 0.80

0

0.02

0.04

0.06

0.08

0.1

0.12

Model 1 Model 3 Model 4

+10%

+5%

0%

-5%

-10%
198

Figure 25. The population trajectories for the Model 4 scenario resulting from increases and decreases in

the annual pelagic juvenile survival rate (-10%, -5%, 0%, +5% and +10%) and a 30% decrease in

mortality for small benthic juveniles only (no expanded TED regulations). Models were based on pre1990 population growth rates of –5%, -3% and 0% (equivalent to λ values of 0.95, 0.97 and 1.0).

Proportion of female offspring is 0.80.

Model 1; Initial Lambda = 0.95; Sex Ratio = 0.80

0

2000

4000

6000

8000

10000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 1; Initial Lambda = 0.97; Sex Ratio = 0.80

0

5000

10000

15000

20000

25000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%

Model 1; Initial Lambda = 1.00; Sex Ratio = 0.80

0

20000

40000

60000

80000

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

+10%

+5%

-5%

-10%

0%
199

Figure 26. The population trajectories for the Model 3 scenario resulting from increases and decreases in

the annual pelagic juvenile survival rate (-10%, -5%, 0%, +5% and +10%) and a 30% decrease in

mortality for small benthic juveniles only (no expanded TED regulations). Models were based on pre1990 population growth rates of –5%, -3% and 0% (equivalent to λ values of 0.95, 0.97 and 1.0).

Proportion of female offspring is 0.80.

Model 3; Initial Lambda = 0.95; Sex Ratio = 0.80

0

500

1000

1500

2000

2500

0 1 0 2 0 3 0 4 0 5 0

Time (yrs.)

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+5%

-5%

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0%

Model 3; Initial Lambda = 0.97; Sex Ratio = 0.80

0

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Figure 27. The population trajectories for the Model 4 scenario resulting from increases and decreases in

the annual pelagic juvenile survival rate (-10%, -5%, 0%, +5% and +10%) and a 30% decrease in

mortality for small benthic juveniles only (no expanded TED regulations). Models were based on pre1990 population growth rates of –5%, -3% and 0% (equivalent to λ values of 0.95, 0.97 and 1.0).

Proportion of female offspring is 0.80.

Model 4; Initial Lambda = 0.95; Sex Ratio = 0.80

0

500

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Model 4; Initial Lambda = 1.00; Sex Ratio = 0.80

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201

CHAPTER 7. IMPACT OF THE PELAGIC LONGLINE FISHERY ON

LEATHERBACK SEA TURTLES

Nancy B. Thompson

Leatherback turtles are the largest of the sea turtle species and display a large range

within the Atlantic Ocean and in the western North Atlantic Ocean, including the Caribbean Sea

and Gulf of Mexico (Pritchard and Trebbau 1984). They inhabit all the oceans of the world and

are found in both coastal and pelagic waters and unlike the other turtle species, all life history

stages beyond the egg are found in the pelagic zone (Pritchard and Trebbau 1984). They may

grow rapidly achieving sexual maturity in as little as 3-6 years or may not reach maturity until as

late as 19 years (Rhodin 1995, Zug and Parham 1996). They nest frequently (up to 7 nests per

year) during a nesting season and nest about every 2-3 years. During each nesting, they produce

about 100 eggs or more in each clutch and thus, can produce 700 eggs or more per nesting

season (Shultz 1975). Hatchlings through subadults may remain in warm tropical/subtropical

waters and when reaching lengths greater than 100 cm carapace length, demonstrate seasonal

movements in the western North Atlantic and range as far north as Canadian waters in the

summer. Turtles that arrive in northern waters can be derived from any Atlantic nesting beach

and based on ocean currents such as the south to north direction of the Gulf Stream, are from the

South American and U.S. beaches. Turtles in northeastern waters are generally > than 100 cm

curved length which is consistent with fishers in northeastern U.S. and the Grand Banks

encounter.

Dutton et al. (1999) describes stock structure and concludes that there may be distinct

nesting subpopulations along the western North Atlantic coast. They conclude at this time that

turtles nesting in St. Croix/Puerto Rico and Trinidad are different from each other and different

from all other nesting areas in the Western North Atlantic based on their genetic analyses.

Turtles nesting in Florida could not be distinguished from those nesting in the nor from those

from the Indian Ocean. They offer several hypotheses about why there is little difference

between these nesting “populations” and caution that these results alone should not be used to

describe stock structure. However, this does mean that the ability to assign turtles to nesting

beaches when away from nesting beaches would be limited to mainland v. St. Croix/Puerto Rico

v. Trinidad using their methods.

Regardless of hypothesized stock structure, the decline measured on beaches of northern

South America, which support the largest nesting aggregation in the western North Atlantic

Ocean, is of immediate concern and the causes need to be identified. The trend in nesting

females in the U.S. has been increasing for the past 20 years (Appendix 1). Measurable trends in

the major nesting area, beaches along the northern coast of South America, were increasing from

the 1970’s to the early 1990’s and have been decreasing since 1992 (Ibid.). Looking at the

nesting numbers for the South American beaches suggests nesting may be cyclic or in fact is on a

real decline since 1992 which contrasts with nesting in the U.S. which has increased nearly 5-

fold from the early 1980’s to the present. The question that remains to be explored is why is

nesting declining along the northern South American coast whereas it has been increasing in the

Caribbean and Florida during the same time period. An answer to this question is explored with
202

a series of hypotheses and within the context of an impact of the U.S. longline fishery in the

western North Atlantic.

Estimated annual leatherback turtle bycatch from the U.S. longline fishery from 1992 to

1999 ranges from 308-1054. Turtles are caught in all waters from the Gulf of Mexico to the

Grand Banks with the largest estimated bycatch in the spring and summer in northeast U.S.,

southeast Canadian, and international waters. Applying the 50% mortality criterion results in

estimated mortalities as presented in Table 1 of Chapter 5, and these range then from 154 to 527

turtles killed annually by the U.S. longline fishery. Estimates of total bycatch suggest that the

estimated annual mortality from each of these areas (NED, NEC) in spring and summer (in the

hundreds) is on the average about an order of magnitude higher (in the tens) than in other areas.

It is reasonable to assume that there are takes and kills by the foreign vessels in this area and the

magnitude of these takes could be considerable given the effort from these fleets as compared to

that from the U.S. fleet

When examining all takes in all human activities for which we have data or estimates,

(Appendix 1), it is clear that for U.S. activities only, the pelagic longline fishery and the

estimated take from the commercial shrimp trawl fishery (estimated at 650 per year) in

combination are the largest known sources of anthropogenic mortality. Under a regime of

constant mortality, as more turtles enter the water, more will likely be caught.

While turtles killed by the longline fishery in the sampling areas off the northeast U.S.

coast are likely > 100 cm carapace length, those killed off the southeast U.S. coast, the Gulf of

Mexico, and the Caribbean can be of any length unless there is some size selectivity of the gear

as there is in loggerheads (Bolten and Bjorndal 1994). The lengths of animals stranding

throughout the Gulf of Mexico and along the southeast U.S. coast while ranging from < 30 cm

curved carapace length, are primarily greater than 130 cm curved carapace length (See Part II).

These animals represent only those dying in waters close enough to the coast to have stranded

and may not be representative at all of the size distributions of turtles in offshore waters where

deaths are unlikely to result in strandings. However, at least in the southeast U.S., these turtles

may be representative of what is taken by the shrimp fishery and other coastal fishing. Sizes of

turtles at sexual maturity have been observed as minimally about 120 cm carapace length with an

average minimum of about 140 cm carapace length (Marquez 1990). Thus, turtles taken by

fishing in coastal waters and longline fishing in northeastern waters are large juvenile to adult

sizes.

Recovery criteria for the leatherback turtle in U.S. western North Atlantic waters (NMFS

and FWS 1992) are used to consider de-listing and are: (1) the adult female population increases

over the next 25 years, as evidenced by a statistically significant trend in the number of nests at

Culebra, Puerto Rico, and St. Croix, U.S.V.I. and along the east coast of Florida, and (2) nesting

habitat encompassing at least 75 percent of nesting activity in the U.S.V.I., Puerto Rico and

Florida is in public ownership and, (3) all priority one tasks have been successfully

implemented. The first criterion requires an increasing trend in nesting females in 3 index

beaches under control by the United States. Based on trend analyses (Appendix 1), the number

of leatherback nests on Florida and U.S.V.I. beaches is increasing at 10.3% and 7.5% per year,

respectively, since 1979. However, the largest leatherback rookeries in the western North
203

Atlantic remain along the northern coast of South America in French Guiana and Suriname.

While Spotila et al. (1996) indicated that turtles may have been shifting their nesting from

French Guiana to Suriname due to beach erosion, analyses show that the overall area trend in

number of nests has been negative since 1987 at a rate of 15.0% per year (Appendix 1).

Chevalier et al. (1999) suggest that this decline could be from both reduced hatching success (as

low as 22% -35% per year) and takes of nesting females by coastal fishing. Previously,

Chevalier and Girondot (2000) suggested that Suriname beaches up to 1992 had shown increases

in nesting and hypothesized that this increase, which correlated with the decline along French

Guiana beaches, was a result of shifts in nesting activity. However, recent trend analyses show a

decline overall in these beaches since 1987. The decline in the major nesting areas for

leatherbacks has been clearly described and the cause of this decline needs to be identified.

To determine the cause of the decline in nesting in the beaches of the Guianas, a series of

hypotheses are offered: (1) the trends represent a natural cycle in nesting of leatherback turtles in

this region; (2) natal homing in leatherbacks is imprecise and the turtles are nesting elsewhere

and not reported or observed nor recognized as migrated from another rookery; (3) the mortality

rate for female turtles has increased over the past 10 years relative to the previous 25 or so for

turtles nesting in the Guianas but not increased to the same extent on females nesting on U.S.

beaches; (4) the mortality rates for any or all life history stages for turtles derived from Guianas

beaches is higher than that for turtles derived from U.S. beaches. The following is a discussion

of each hypothesis:

1. There is a natural, decadal cycle in female nesting. Biological cycling of this sort is

typically seen as a density dependent response to organisms that can increase in numbers

very rapidly and as a biological phenomenon for this species does not seem logical.

However, Schulz (1975) describes the Suriname beaches along the coast of South

America as dynamic and undergoing regular cycles of erosion and accretion which means

beach availability cycles. Schulz (1975) also indicates that over the past few centuries

the availability of nesting beach to sea turtles in general has been rare along the Suriname

coast as beaches have appeared only relatively. Schulz (1975) indicates that these cycles

are in about 10 year periods. Chevalier et al. (1999) suggest that there are shifts in

nesting along this coastal region and that turtles have been shifting nesting activity from

French Guiana to Suriname as a result of beach availability and quality.

2. Turtles have shifted to other nesting beaches and may be unreported. Genetic studies

indicate that turtles nesting on Florida beaches and beaches of the Guianas beaches are

not distinguishable and the increases seen in Florida beaches as well as those throughout

the Caribbean, could be from South American nesting females. From 1992 to 1997, the

numbers of nests in French Guiana decreased from about 50,000 nests to less than 15,000

nests, a 75% decrease in total nests reported. This same relative amount of decrease in

nests was reported for Suriname beaches. While the rate of increase in nesting on U.S.

beaches is similar to the decrease seen in South America, the total numbers of nests is

much less than expected if all females have shifted to U.S. beaches. This type of

emigration could explains the lack of distinction seen in mainland nesting Atlantic

leatherbacks, but would not explain the differences maintained between the insular

populations and the mainland population. In the eastern North Atlantic Ocean, nesting in
204

Gabon is estimated at almost 5,000 females and has been described as stable (Spotila et

al. 1996). What other nesting is occurring along the West African North Atlantic coast is

not known. The level of decrease in the South American beaches reflects the increase in

nesting seen from U.S. beaches for the same period of time. However, the overall annual

total number of nests is still significantly less for U.S. than South American beaches.

3. The mortality rate for adult females has increased over the past ten years causing a

decrease in the number of nesting females. For decreases in nesting to be observed on

South American beaches but not U.S. beaches suggests that this may be true for turtles

nesting in South America only. Spotila et al. (1996) indicated that the number of turtles

killed in the South American offshore fishery had increased “dramatically”. It is not

known what the magnitude of this increase is and cannot be identified as the cause of the

decline, but neither can it be discounted as a direct cause of the decrease. Coastal gillnet

fisheries and shrimp trawling do occur in the Guianas and could be contributory to

mortality (Chevalier et al. 1999, Chevalier and Girondot 2000). Shrimp trawlers in these

waters are not required to use TED’s (Chevalier and Girondot 2000). The decreases seen

at these beaches and increases in nesting in U.S. beaches, suggests that some source of

mortality may be effecting the South American nesting females and not effecting the U.S.

and Caribbean nesting females. Of course, the signal may yet to be measured on U.S.

beaches but this would suggest differential growth rates as well, with turtles nesting along

South America growing faster resulting in a measurable decrease in females before

observed in other nesting beaches. Given the range and movements of these turtles, it

would be expected these turtles exhibit the same growth rates.

4. The mortality rates for any or all life history stages have increased. This increase in

mortality rate could be impacting turtles from U.S. beaches and throughout the Atlantic

as well and we have yet to measure this as decreases on the nesting beach but are seeing

the effect on South American beaches. The same argument about differential growth rates

would have to be applied here as for hypothesis 3. The proportion of turtles by nesting

beach origin is likely variable in any given year due to turtles essentially utilizing the

entire Atlantic Ocean basin and exhibiting even transoceanic movements. Assuming that

the longline fishery and other human activities away from the nesting beach do not

discriminate based on beach of origin, then it would be expected that this mortality would

be observed as decreases in all nesting areas. Either the signal has not been measured in

U.S. beaches or this mortality is selective for turtles from South American beaches only.

Any mortality from U.S. longline fishing would be expected to produce the same effect for

all western North Atlantic leatherback turtles regardless of beach of origin or “population” if

they were mixing on the high seas. For longline effort measured in total hooks fished, the U.S.

effort is less than 10% of the total effort or hooks in the North Atlantic as prosecuted by nations

party to ICCAT (see Chapter 1), but the U.S. accounts for 25-33% (mean=28%) of the swordfish

yield, 1990-1997 and 11-26% (mean=18%) of the tunas yield from the North Atlantic. Thus,

efficiency of the U.S. fleet as compared with foreign fleets and based on CPUE is 4-8 times

greater for swordfish and 2-3 times greater for tunas. How this efficiency relates to the capture

of sea turtles is not known. The bycatch rate of sea turtles is most significantly correlated with
205

swordfish catch, and secondly to shark, but negatively correlated with tuna (all species) (Chapter

2). Results also indicate that effort in terms of number of hooks set is not significant compared

to the time-area factors. However, whether based on effort or yield when determining the

relative impact of the domestic fishery relative to the foreign fleet, it is clear that the foreign

fleet, when overlapping with the U.S. fleet, catches and kills turtles. Again, this mortality would

not be expected to be selective and target turtles by beach of origin.

Turtles are taken and killed by the U.S. pelagic longline fishery. The total effort as measured

in total hooks is larger for the foreign fleet than the U.S. fleet, although the magnitude of this

take and mortality is not known and may be larger than that by the U.S. fleet alone. The greatest

overlap in effort and numbers of leatherback turtles occurs in the entire western North Atlantic

(Figure 7, Chapter 8). Thus, it would be expected that this mortality would be evidenced on

nesting beaches throughout the western North Atlantic Ocean. It is possible, but unlikely that

this signal has not been observed in U.S. beaches. Takes and mortality from the U.S. longline

fishery are relatively large and while could be contributory especially for populations undergoing

other significant stresses, it is difficult to argue that this alone explains the decreases observed in

the largest nesting area of the western North Atlantic. This fishery, in combination with the

foreign longline fleets and coastal fishery could produce sufficient mortality to result in the

decreases evident on South American nesting beaches.

On the other hand, large removals of eggs alone could produce the same result and, if

turtles do grow to maturity within 5 years, would be evidenced on the nesting beach quickly.

There is compelling evidence to suggest that whatever is causing the decline in nesting females

along the South American coast is not effecting the numbers of females nesting on U.S. and

Caribbean beaches at this time or is measurable on U.S. beaches at this time. It remains to be

seen if turtles are emigrating from South American beaches to U.S. and others, there is still a

possibility given the cyclic nature of the South American beaches and the inability to distinguish

subpopulations at this time. Chevalier et al. (1999) suggest that observers need to be placed on

vessels fishing working off the coastal Guianas and that tag recapture experiments need to be

conducted to determine the effects of fishing on these nesting females and to determine

emigration rates, respectively. To determine the impact of the longline fleets (both U.S. and

foreign) on these “populations”, first there must be some apportionment of turtles by nesting

beach origin, then stage or age specific mortality rates must be quantified. These parameters

could be determined by research and monitoring including: continuing to pursue genetic studies

to describe stock structure; continuing to place observers on vessels coupled with studies such as

use of archival tags to determine mortality rates; pursuing methods to age leatherback turtles and

subsequently develop growth models; and exploring methods for estimating stage or age specific

mortality rates. While there are takes and kills by the pelagic longline fishery and these takes

may be contributory to declines observed, it appears that the U.S. nesting numbers are

increasing. It is clear that the immediate concern is that French Guiana and Suriname must work

towards identifying the causes of decline along their beaches. Without this effort, even with the

elimination of takes by the longline fishery, it appears unlikely that these declines would be

reversed. If immediate measures to reduce identified mortalities are implemented by French

Guiana and Suriname, these alone may be sufficient to reverse the declines.
206

Literature Cited

Bolten, A.B. and K.A. Bjorndal. 1994. Life history model for the loggerhead sea turtle (Caretta

caretta) population in the Atlantic: Potenial impacts of a longline fishery. U.S.

Department of Commerce NOAA Technical Memorandum NMFS-SWFSC-201:48-55.

Chevalier, J., X. Desbois, and M. Girondot. 1999. The reason for the decline of leatherback

turtles (Dermochelys coriacea) in French Guiana: a hypothesis p.79-88. In Miaud, C. and

R. Guyétant (eds.), Current Studies in Herpetology, Proceedings of the ninth ordinary

general meeting of the Societas Europea Herpetologica, 25-29 August 1998 Le Bourget

du Lac, France.

Chevalier, J. and Girondot, M. 2000. Recent population trend for Dermochelys coriacea in

French Guiana: U.S. Department Commerce NOAA Technical Memorandum NMFSSEFSC-436:56-57.

Dutton, P.H., B.W. Bowen, D.W. Owens, A. Barragan, and S.K. Davis. 1999. Global

phylogeography of the leatherback turtle (Dermochelys coriacea). Journal of Zoology

248:397-409.

Marquez, M.R. 1990. FAO species catalogue. Vol.11: Sea turtles of the world. An annotated and

illustrated catalogue of sea turtle species known to date. FAO Fisheries Synopsis. No. 125,

Vol.11. Rome, FAO. 81pp.

National Marine Fisheries Service and U.S. Fish and Wildlife Service. 1992. Recovery Plan for

Leatherback Turtles in the U.S. Caribbean, Atlantic and Gulf of Mexico, National Marine

Fisheries Service, Washington, D.C., 65 pp.

Pritchard, P.C.H. and P. Trebbau. 1984. Family Dermochelyidae, Dermochelys coriacea. In The

Turtles of Venezuela, Society for the Study of Amphibians and Reptiles, Contribution to

Herpetology No. 2:249-267.

Rhodin, A.G.J. 1985. Comparitive chondro-osseous development and growth of marine turtles.

Copeia 1985:752-771.

Schultz, J.P. 1975. Sea turtles nesting in Surinam. Zoologische Verhandelingen (Leiden) Number

143:172 pp.

Spotila, J.R., A.E. Dunham, A.J. Leslie, A.C. Steyermark, P.T. Plotkin, and F.V. Paladino. 1996.

Worldwide population decline of Dermochelys coriacea: are leatherback turtles going

extinct? Chelonian Conservation and Biology 2:209-222.

Zug, G.R. and J.F. Parham. 1996. Age and growth in leatherback turtles, Dermochelys coriacea

(Testudines: Dermochelyidae): a skeletochronological analysis. Chelonian Conservation

and Biology 2:244-249.
207

CHAPTER 8. EVALUATION OF POSSIBLE REASONABLE AND

PRUDENT ALTERNATIVES BEING CONSIDERED

Wayne N. Witzell, Ransom A. Myers, and Sheryan P. Epperly

There are a number of possible reasonable and prudent alternatives being discussed to

allow the continuation of the pelagic longline fishery. Several workshops have been held with

scientists and industry to discuss possible means to reduce both the number of interactions and

the mortality resulting from those interactions. A few are reviewed below with what little

information is available.

Hook Styles

A variety of fishhook styles are used in the pelagic longline fisheries 2000 (D. Lee,

personal communication37). Boats may fish several styles of hooks at any one time depending on

target species and hook availability. The traditional “J” style hooks are commonly used for

swordfish and the circle hooks are commonly used for tunas. It has been proposed that a change

in style of hooks used during pelagic longline fishing may effect the survival of sea turtles

captured incidental to their fishing operations 38,39. That optimism arose from promising results

on other taxa.

Recent studies of circle and “J” hooks in the U.S. recreational fisheries for billfish and

bluefin tunas have provided interesting results. Significantly more sailfish were jaw hooked,

including corner of mouth, using circle hooks (98%) than with “J” hooks (44%). Only 2% of the

sailfish were deeply hooked using circle hooks but 46% of the “J” hooked sailfish were deeply

hooked (Prince et al. in press). Additionally, deep hooking by circle hooks with severely offset

points was comparable (44%) with the deep hooking percentage for “J” hooks (Prince et al. in

press).

There was a significant association between hook type and hook location (p<0.05) found

in the U.S. catch and release recreational fishery for Atlantic bluefin tuna, Thunnus thynnus

(Skomal et al. in press). In that study, 94% of the bluefin tuna caught with circle hooks were jaw

and 3.9% were hooked in the pharynx or esophagus while 52% caught with straight “J” hooks

were jaw hooked and 34% were hooked in the pharynx or esophagus. Based on these results,

Skomal et al. (in press) estimated that 4% of the circle hooked captures and 28% of the straight

 

37 Dennis Lee, National Marine Fisheries Service, SEFSC, Miami, Fla.. Personal communication to Wayne Witzell,

National Marine Fisheries Service, Miami, Fla., January 13, 2001.

38 Kleiber, P. and C. Boggs. 2000. Workshop on reducing sea turtle takes in longline fisheries. Miami, August 31-

September 1, 1999. Unpublished Report. National Marine Fisheries Service, SWFSC, Honolulu, Hawaii, 16 pp.

39 Working Group on Reducing Turtle Bycatch in the Hawaii Longline Fishery, Report of First Meeting September

12-13, 2000 Los Angeles. Unpublished Report. National Marine Fisheries Service, SWFSC, Honolulu, Hawaii, 11

pp.
208

hook captures would have resulted in mortality, and recommended that circle hooks be promoted

for use in catch and release recreational fisheries for juvenile bluefin tuna.

An experiment was designed to study gear effects on sea turtle bycatch by the pelagic

longline fishery. 40 Preliminary data concerning the use of “J” and circle hooks experimentally

fished on commercial Spanish longline vessels in the Azores Islands July-December 2000 is now

available (A. Bolten, personal communiation41,42,43) The experiment consisted of 93 longline

sets, each set consisting of 1,500 hooks baited with squid. The target species were swordfish and

blue sharks. Three hook types were tested: straight “J”(Mustad #76800 D 9/0), reversed/offset

“J” (30-32o) (Mustad #76801 D 9/0), and circle (Mustad #39960 ST 16/0). The hooks were

alternated along the set and because there were 8 hooks between buoys, the relationship between

hook type and hook position on the gear varied. The order of gear set was thus: large buoy with

radar reflector, 4 small buoys, large buoy, four small buoys, large buoy with reflector, etc.(Alan

Bolten, personal communication44). The branchline (gangion) length, including leader, was 14

m and they were spaced 45 m apart along the mainline. Buoy lines were 5.4-14.4 m long: line

length on large buoy with radar reflector was 14.4 m, large buoy line length was 10.8 m, and the

line length on the small buoys was 5.4 or 10.8 m, depending on fishing conditions and was

determined by the captain. A single 25.4 m vessel was used throughout the experiment.

A total of 232 loggerhead, 4 leatherback, and 1 green turtle were caught. Catch per unit

effort (CPUE) for all species combined was estimated at 1.7 turtles/1,000 hooks. There was no

significant difference in the total numbers of turtles caught by each hook type (Chi-square test,

p=0.136). However, there was a significant difference among the 3 hook types in the location of

hooking in the turtles (Chi-square test, p<0.001):

Percent Hooked in theThroat

Standard “J” Hook 57%

Offset “J” Hook 46%

Circle Hook 11%

 

40 Bolten, A.B., H.R. Martins, and K.A. Bjorndal, eds. 1998. Workshop to design an experiment to determine the

effects of longline gear modification on sea turtle bycatch rates. Unpublished report. University of Florida and

Departamento de Oceanografia e Pescas, Gainesville, FL and Horta, Portugal, 54 pp.

41 Alan Bolten, University of Florida, Gainesville. Personal communication (E-Mail) to Sheryan Epperly, National

Marine Fisheries Service, SEFSC, Miami, Fla., November 16, 2000.

42 Bolten, A.B., University of Florida, Gainesville. Personal communication (Phone) to Sheryan Epperly, National

Marine Fisheries Service, SEFSC, Miami, Fla., January 15, 2001.

43 Bolten, A., H. Martins, E. Isidro, R. Ferreira, M. Santos, A. Giga, B. Riewald, and K. Bjorndal. Preliminary

results of an experiment to evaluate effects of hook type on sea turtle bycatch in the swordfish longline fishery in the

Azores. Unpublished report, 2 pp.. A.B. Bolten , University of Florida, Gainesville. Personal communication (EMail) to Nancy Thompson and Sheryan Epperly, National Marine Fisheries Service, SEFSC, Miami, Fla, January

13, 2001.

44 Bolten, A.B., University of Florida, Gainesville. Personal communication (E-Mail) to Sheryan Epperly, National

Marine Fisheries Service, SEFSC, Miami, Fla., January 24, 2001.
209

Additionally, there was a tendency for more turtles to be caught on hooks closest to buoys, but

there was no significant effect of hook position along the mainline on turtle bycatch (Chi-square

test, p = 0.515).

The use of circle hooks to reduce sea turtle serious injury shows encouraging results. The

presumption is that animals that ingest the hooks are less likely to survive an interaction than

animals that are hooked in the mouth. Use of circle hooks would reduce the number of animals

ingesting the hook, but not the total number being hooked. However, changing from “J” to circle

hooks may adversely affect the catching success for target species, particularly for the swordfish

fleet. In the Azores experiment, there was a significant difference among the hook types in the

numbers of swordfish caught (Chi-square test, p < 0.001). The circle hook caught 262 swordfish

and the “J” hook caught 381 swordfish, a 31.1% reduction.

Literature Cited

Prince, E.D., M. Ortiz, and A. Venizelos. In press. A comparison of circle and “J” hook

performance in recreational catch and release fisheries for billfish. In American Fisheries

Society Special Publication. National Symposium on Catch and Release in Marine

Recreational Fisheries, December 5-8, 1999.

Skomal, G.B., B.C. Chase and E.D. Prince. In press. A comparison of circle and straight hooks

relative to hooking location, damage, and success while catch and release fishing for Atlantic

bluefin tuna. In American Fisheries Society Special Publication. National Symposium on

Catch and Release in Marine Recreational Fisheries, December 5-8, 1999.
210

Time-Area Closure

Supplemental Bycatch Analysis to Determine Times and Areas of High Interactions

Bycatch data from 1992-1999 was obtained from the U.S. Pelagic Observer Program for

both loggerhead and leatherback turtles. Generalized additive models were used to analyze the

data. Seasonal bycatch of loggerhead and leatherback turtles appear similar within geographical

regions. Number of turtles caught is higher in more northern locations, particularly in the

Northeast Atlantic Ocean. For both turtle species, catches in the more southern regions are

limited to the winter months. Patterns of catch in the coastal regions may follow migratory

patterns: the southern bycatch decreases with day of the year in the Gulf of Mexico, while along

the coast of New England it increases. Peak bycatch numbers for the loggerhead (Fig. 1) and

leatherback (Fig. 2) occur in the Northeast Distant Atlantic region during mid-August.

The most recent Biological Opinion for the Highly Migratory Species Fishery45 included

a reasonable and prudent alternative (RPA) which would effectively close the fishery in the

Northeast Distant Area (NED) from July-December. The NED has been identified as an area of

high turtle interactions. The NMFS SEFSC was asked to evaluate whether a time/area closure

smaller than the entire geographic extent and temporal duration given in the RPA could achieve

the same degree of reduction in turtle takes with less impact on target catch. The SEFSC

provided the following analysis.46 The conclusion was that the interactions occur throughout the

entire NED and not just in some small portion of it. An “L” shaped portion of the NED was

closed under an emergency regulation for the period October 10, 2000-April 9, 2001 (65 FR

60899-60892, October 13, 2000).

 

45 Endangered Species Act - Section 7 Consultation Biological Opinion. Reinitiation of Consultation on the Atlantic

Pelagic Fisheries for Swordfish, Tuna, Shark and Billfish in the U.S. Exclusive Economic Zone (EEZ): Proposed

Rule to Implement a Regulatory Amendment to the Highly Migratory Species Fishery Management Plan; Reduction

of Bycatch and Incidental Catch in the Atlantic Pelagic Longline Fishery, 118 pp. Consultation conducted by

National Marine Fisheries Service, Office of Protected Resources, Silver Spring, Md., June 30, 2000.

46 Turtles involved with longline gear in the Gand [sic] Banks. Unpublished report. National Marine Fisheries

Service Southeast Fisheries Science Center, Miami, FL. Attachment to E-Mail from Joseph Powers, National

Marine Fisheries Service, SERO, St. Petersburg, Fla. to Karyl Brewster-Geisz, National Marine Fisheries Service,

SF, Silver Spring, Md., August 25, 2000.
211

Figure 1. Seasonal counts of loggerhead turtles caught during each longline set from 1992 to

1999 (open circles). Fitted values from the model are given by a solid line and their point wise

upper and lower confidence intervals are given by dotted lines. Individual plots represent 11

areas and are displayed in a pattern that roughly follows their relative north/south and east/west

geographical location.
212

Figure 2. Seasonal counts of leatherback turtles caught during each longline set from 1992 to

1999 (open circles). Fitted values from the model are given by a solid line and their point wise

upper and lower confidence intervals are given by dotted lines. Individual plots represent 11

areas and are displayed in a pattern that roughly follows their relative north/south and east/west

geographical location.
213

Turtles Involved with Longline Gear in the Grand Banks

Data from the large pelagic logbook and the NMFS observer file were used to identify

times and locations of turtle involvement with longline gear in the Grand Banks during the

months July through December.

Description of data sources

Large pelagic logbook (LPL):

U.S. Atlantic, Caribbean and Gulf of Mexico fishing vessels which land swordfish have

been required to provide daily records of effort and catch since October 1986. Numbers of

turtles involved, injured, and killed have been reported to this file since 1992. Although a variety

of gear types are represented, the predominant gear type (90% of vessels reporting) is longline

gear. Fishing effort in this area is seasonal. Very little effort was reported in December.

Table 1. Numbers of turtles reported involved, injured, or killed by pelagic longline vessels in

the Grand Banks between July and December 1992-1999.

Green Hawksbill Kemp’s

Ridley

LeatherbackLoggerheadunknown

involved 74 129 16 793 2020 10

injured 1 0 0 6 35 0

killed 0 0 0 8 3 0

NMFS Observer (NMFSO):

National Marine Fisheries Service observers have observed a random sample of longline

vessels targeting swordfish and tuna since 1992. Numbers of fish and turtles landed, discarded

dead and discarded alive are recorded in this file as well as gear and location information.

Table 2. Numbers of turtles observed released alive or killed by pelagic longline vessels in the

Grand Banks between July and December 1992-1999.

Green Leatherback Loggerhead unknown

released alive 8 106 225 1

released dead 1 0 0 0
214

-60 -58 -56 -54 -52 -50 -48 -46 -44 -42 -40 -38 -36 -34 -32 -30 -28 -26 -24 -22 -20

36

38

40

42

44

46

48

50

52

54

1992-1999 Observer Data (July - November)

 hooks set

 turtles reported

July

August

October

August

September

October

September

October

September

October

Two degree square

 high turtle months

Figure 3. Locations of observed effort (hooks set) and turtle involvement (turtles reported) from

NMFSO form July through November are shown on this map. Squares indicate areas of highest

turtle involvement. The relevant months of high involvement for each square are indicated by

listing the months in the square diagram above this caption.

Observer data were grouped within each year by month and two degree square. A GLM

model was run: all turtles reported vs year and month-square. The number of hooks reported in

the month-square was used as a weighting variable. Month-squares were ranked based on the

LSMEAN value from the GLM. The ten month-squares with the highest estimated turtle

involvement (based on the LSMEAN values) are shown in Figure 3. The month written inside

the square indicates that the square was high for that month.

Table 3 gives the percentage decreases in turtles involved (relative to total involvement in

the Grand Banks July-Dec), effort in hooks, and catch of other species resulting from closure of

the U.S. fishery in the Grand Banks, using NMFS Observer data. Table 5 gives the same

information based upon Large Pelagic Logbook data. Decreases resulting from closures of high

month-squares (based on NMFSO) are shown in Table 4.
215

Table 3. The percent decrease with total closure for month based on observer records.

All Turtles Swordfish Tuna Mako Swordfish Blue HOOKS

Landed Sharks Dead Disc.Sharks

total 341 6240 1904 892 1703 11263 265744

July 28% 39% 22% 60% 50% 30% 35%

August 25% 16% 4% 20% 18% 18% 14%

September 36% 19% 23% 9% 15% 13% 16%

October 9% 24% 29% 8% 13% 29% 26%

November 2% 3% 23% 3% 4% 10% 9%

Table 4. The percent decrease with closure of high two degree squares for month based on observer records.

All Turtles Swordfish Tuna Mako Swordfish Blue HOOKS

Landed Sharks Dead Disc.Sharks

July % 6% 8% 3% 14% 10% 10% 6%

Aug % 9% 4% 0% 4% 3% 3% 4%

Sept % 24% 13% 15% 6% 9% 7% 10%

Oct % 1% 9% 7% 3% 3% 7% 8%

Table 5. The percent decrease with total closure for month based on logbook records.

All Turtles Swordfish Tuna Mako Swordfish Blue HOOKS

Month Landed Sharks Dead Disc.Sharks

3095 119237 23659 6846 11936 273307 4749322

July 36% 22% 14% 39% 30% 20% 22%

August 24% 27% 19% 28% 22% 29% 25%

September 24% 29% 31% 17% 23% 23% 26%

October 15% 19% 23% 13% 19% 21% 20%

November 1% 3% 12% 3% 5% 7% 7%

December 0% 0% 1% 0% 0% 0% 0%
216

-60 -58 -56 -54 -52 -50 -48 -46 -44 -42 -40 -38 -36 -34 -32 -30 -28 -26 -24 -22 -20

36

38

40

42

44

46

48

50

52

54

1992-1999 Observer Data

 hooks set

 turtle reported dead (1 green turtle)

Figure 4. Location of turtles reported dead. (NMFSO)

-60 -58 -56 -54 -52 -50 -48 -46 -44 -42 -40 -38 -36 -34 -32 -30 -28 -26 -24 -22 -20

36

38

40

42

44

46

48

50

52

54

Pelagic Logbook 1992 - 1999 (July - December)

 effort in hooks

 turtles reported

Figure 5. Locations of reported effort (hook set) and turtle involvement (turtles reported) from

LPL form July through December are shown on this map
217

-60 -58 -56 -54 -52 -50 -48 -46 -44 -42 -40 -38 -36 -34 -32 -30 -28 -26 -24 -22 -20

36

38

40

42

44

46

48

50

52

54

Pelagic Logbook 1992 - 1999 (July - December)

 effort in hooks

 turtles reported dead (11 turtles)

Figure 6. Locations or turtles reported killed (LPL)
218

-90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20

-40

-30

-20

-10

0

10

20

30

40

50

60

Swordfish Catch - 1996

 Foreign

 Domestic 1 - 5 MT

 5 - 10 MT

10 - 25 MT

25 - 50 MT

50 - 100 MT

 > 100 MT

Figure 7. Domestic (U.S.) and foreign swordfish catch in 1996. Foreign catch data are

incomplete and includes only North American, Asian, and Spanish reported landings. Notably

not included are catches from Caribbean, Central and South America, and other European

countries.
219

In response to a request from the NMFS Office of Sustainable Fisheries, the SEFSC

provided the results of a GLM model run on the logbook data for 2 degree latitude/longitude

squares (J. Cramer personal communication47) (Table 5) and output from these analyses were

provided (J. Cramer personal communication47) (Appendix 5). The conclusions were the same as

from analyses based on the observer data.

Table 5. The number of reported interactions (LPL) with sea turtles by the pelagic longline fleet.

The first square is between 43° to 45° N latitude and 45° to 47° W longitude. The number is in

the center of the two degree square. These are the highest 10 month/squares with 1 being the

highest LSMEAN from the GLM.

logbook

square July August September October

4446 8

4642 1 4 3

4644 2 6

4640 9

4442 7

4248 5

5044 10

 

47 Jean Cramer, National Marine Fisheries Service, SEFSC, Miami, Fla. Personal Communication (E-Mail) to Karyl

Brewster-Geisz, National Marine Fisheries Service, SF, Silver Spring, Md., August 28, 2000.
220

Evaluation of the Effect of Sea SurfaceTemperature and Time of Set on Sea Turtle Bycatch

off the Northeast U.S.

One of the alternative reasonable and prudent alternatives identified in the most recent

Biological Opinion was to manage all pelagic longline vessels fishing north of 35 N latitude so

that they fish only in waters with sea surface temperatures cooler than 64 C. It furthermore

stipulated that gear shall be not be set prior to 10 p.m. 48

Sea Surface Temperature

Previous analyses have described factors that appear to influence rates of sea turtle

interactions with the Atlantic pelagic longline fishery and suggested that sea surface temperature

or time of set may influence the probability of interacting with a sea turtle (Hoey 199849, Hoey

and Moore 199950). The datasets used for those analyses were updated through 1999 and

graphed (Fig. 8 and 9) to assess the effect of sea surface temperature on turtle bycatch in the

Northeast U.S. (MAB and NEC areas) and Northeast Distant (NED) fishing areas (Hoey 200051)

(see Chapter 2 for definition of these areas).

These data are difficult to interpret because they do not represent a random sample of

water temperatures in the 2 areas and the patterns observed may be an artifact of the distribution

of fishing effort (Fig. 10). While it appears that the distribution of turtles may be affected by

water temperature (a reasonable conclusion since sea turtles generally are poikilothermic), there

is no clear pattern for swordfish, the primary target species in the area. The pattern observed for

the target species is completely opposite in the two areas, with swordfish tending to be caught at

a higher rate at higher temperatures on the Grand Banks and caught a higher rate at lower

temperatures in the Northeast Coastal Area. Thus, an attempt to restrict the fishery to cooler

waters where turtles are less likely to occur cannot be done without some potential impact on the

catch of the target species.

 

48 Endangered Species Act - Section 7 Consultation Biological Opinion. Reinitiation of Consultation on the Atlantic

Pelagic Fisheries for Swordfish, Tuna, Shark and Billfish in the U.S. Exclusive Economic Zone (EEZ): Proposed

Rule to Implement a Regulatory Amendment to the Highly Migratory Species Fishery Management Plan; Reduction

of Bycatch and Incidental Catch in the Atlantic Pelagic Longline Fishery, 118 pp. Consultation conducted by

National Marine Fisheries Service, Office of Protected Resources, Silver Spring, Md., June 30, 2000.

49 Hoey, J. 1998. NEFSC pelagic longline data review & analysis of gear, environmental, and operating practices

that influence pelagic longline interactions with sea turtles. Unpublished Report. National Fisheries Institute, Inc.,

Arlington, VA Final Contract Report NOAA-Contract – 50EANA700063 to National Marine Fisheries Service

Northeast Regional Office, Gloucester, MA, 32 pp.

50 Hoey, J. and N. Moore. 1999. Captain’s report. Multi-species catch characteristics for the U.S. Atlantic pelagic

longline fishery. Unpublished Report. National Fisheries Institute, Arlington, VA report for National Marine

Fisheries Service Southeast Regional Office, St. Petersburg, FL (MARFIN Grant – NA77FF0543) and Northeast

Regional Office, Gloucester, MA (Saltonstall-Kennedy Grant – NA86FD0113), 78 pp.

51 John Hoey , National Marine Fisheries Service, ST, Silver Spring, Md. Personal Communication (E-Mail) to K.

Wang, National Marine Fisheries Service, SERO, St. Petersburg, Fla., June 2, 2000. Unpublished Report. Requested

re-examination of gear, environmental, and opening practices associated with sea turtle longline interactions, 26 pp
221

Surface water temperature is shown in regression tree analysis to be an important factor

in the rate of bycatch of leatherbacks and loggerheads in the NED area in certain years (see

Chapter 2). For leatherbacks, the temperature effect is nested within the month effect, and for

loggerheads, the month effect is nested within the temperature factor. For all species combined,

lower temperature is associated with lower bycatch rate. While this association is true also for

loggerheads only, for leatherbacks, lower temperature actually accounts for a slightly higher

bycatch rate, so if indeed temperature is a significant factor in bycatch rate the interaction may

be species-specific. Both temperature and month effects may however simply be a reflection on

the seasonal distribution of fishing effort, since effort tends to be concentrated in the 3rd quarter

in NED, which is likely to have a higher average temperature than in other quarters combined.
222

Figure 8. Catch rates of swordfish, blueshark, hardshell (Cheloniidae) and leatherback sea turtles

in the Northeast Distant Area. (A) finfish catch per set and (B) sea turtle catch per set.

(A)

(B)

54

57

60

63

66

69

72

75

swordfish

0

20

40

60

80

100

Temperature (deg F)

Catch per Set

swordfish

blueshark

54

57

60

63

66

69

72

75

hardshell

0

1

2

3

4

5

Temperature (deg F)

Catch per Set hardshell

leatherback
223

Figure 9. Catch rates of swordfish, blueshark, hardshell (Cheloniidae) and leatherback sea turtles

in the Northeast Coastal Area. (A) finfish catch per hook and (B) sea turtle catch per hook.

(A)

(B)

50

55

60

65

70

75

80

85

swordfish

0

5

10

15

20

25

Temperature (deg F)

Catch per Set

swordfish

blueshark

50

54

58

62

66

70

74

78

82

86

hardshell

0

0.05

0.1

0.15

0.2

0.25

Temperature (deg F)

Catch per Set

hardshell

leatherback
224

Figure 10. Distribution of effort (sets) across temperature intervals. (A) the Northeast Distant

Area and (B) the Northeast Coastal Area.

(A)

(B)

54

56

58

60

62

64

66

68

70

72

74

SETS

0

5

1 0

1 5

2 0

2 5

3 0

3 5

4 0

4 5

Temperature (deg F)

Distribution of Effort (Sets) over 

Temperature Intervals

50

54

58

62

66

70

74

78

82

86

SETS

0

2 0

4 0

6 0

8 0

100

Temperature (deg F)

D istribution of Effort (Sets) over 

Temperature Intervals
225

Time of Set

Likewise time of day when sets were made also did not represent a random sample of

times throughout a day (Fig. 11). Turtles appeared to be captured whenever sets were made (Fig.

12).

Figure 11. Distribution of effort (sets) across time intervals.

Distribution of Effort (sets) over Time

0

20

40

60

80

100

120

120013001400150016001700180019002000210022002300

Time Intervals

frequency
226

Figure 12. Catch rates of hardshell (Cheloniidae) and leatherback sea turtles in the Northeast

Coastal and Northeast Distant Area. (A) hardshell turtles and (B) leatherback turtles.

(A)

 (B)

Hardshell Turtle Catch Rate

0.000

0.200

0.400

0.600

0.800

1.000

120013001400150016001700180019002000210022002300

Time Intervals 

catch per set

Leatherback Turtle Catch Rate

0.000

0.100

0.200

0.300

0.400

0.500

0.600

120013001400150016001700180019002000210022002300

Time Intervals

catch per set
APPENDIX 1:

META-ANALYSIS OF POPULATION

TRENDS OF LOGGERHEAD

AND LEATHERBACK TURTLES

Ransom A. Myers

Keith G. Bowen

Leah Gerber
1 Introduction

Critical conservation decisions often have to be made from widely scattered local data that

may show what appears to be contradictory trends. Traditionally, each trend was examined independently to determine if they show statistically significant results. This approach–determining the

proportion of studies individually exhibiting statistical significance in the prescribed direction–is

known as “vote counting” in the meta-analysis literature, and is inherently flawed (Hedges and

Olkin 1985). Hedges and Olkin (1980) showed that as the number of studies becomes large, the

proportion of studies yielding significant results is approximately the average power of the test.

Here we suggest an improved approach. Our goal is to obtain the most powerful estimates, and

still model the variation among sites.

2 A Mixed Model Approach

We begin with the simplest of models. Let Xit be the estimate of abundance of nesting females

at each site i in year t. We will examine the simplest possible dynamic model for each site, given

that each site began with an initial number of nesting females in the first year of the study, i.e. at

t 

0 each site had xi0 nesting females. If each population is changing at a constant rate over the

period of time of the censuses, we have

Xit 

Xi0e

rit

εit

where ri

is the instantaneous rate of population change, Xi0 is the initial population size of the ith

population, and εitis the error in the estimate of abundance and deviations from the assumed model

(sometimes called “process error”).

It is unlikely that all the nest sites will have exactly the same rate of change, so we will investigate a simple mixed effect model where we assume that ri N 

μr σ

2

r 

, where μris the mean

instantaneous rate of change in population size for the nesting sites and σ

2

r

is the variance among

populations.

We will investigate two approaches to the above model: (1) we log transform the data and use

a linear mixed model and (2) we will use the raw counts and use a generalized linear mixed model.

the second approach is more flexible, and can handle years in which no turtles were observed, but

the first is easier to implement and understand.

3 A Linear Mixed Model

First, we can log transform the above model. Let xit 

logXit, then we have

xit xi0  rit  εit 

228
Now ri can be interpreted as a slope, and xi0 can be interpreted as an intercept. The initial population number is also observed with error so that it is clearer if we define the true initial log

abundance to be a parameter, θi true xi0, which we will estimate. The above equation becomes

xit 

θi  rit  εit 

The nesting sites vary in size and suitability for nesting, and these properties can be thought of

as intrinsic to each site, and unrelated to any other site. Since the intercept for each nesting site

determines the initial density, we treat the intercepts as site-specific fixed effects. The rate of

change of the population at each nesting site, however, may reflect larger-scale phenomena such as

climate or management policies. Therefore we model the slope for each nesting site as a random

effect.

We used restricted maximum likelihood (REML) to fit the linear mixed models. REML can

be thought of as an adjustment to the degrees of freedom accounting for the fixed effects, giving

unbiased variance estimates (Searle et al. 1992). The likelihood ratio test (lrt) was used to compare

the fit of different models.

We estimated the parameters of this model under two different assumptions for εit. First, we

assumed that the variance of εitis the same for all sites. That is, we assume that εit N 

0 σ

2

,

where σ

2

is estimated from the data. An alternative approach is to assume that the variances are

primarily due to factors unrelated to sample size, and estimate a separate variance, σi for each site.

For loggerheads, we were interested in if the population growth rate has changed after the

introduction of TEDs in 1989. We thus fit the piecewise linear mixed model:

Xit Xi0e

rit

r 

i

t 

εit

where t 	
 0 if t 
 1990 and t 	 t  1989 otherwise, and r 	

i

is the difference in the instantaneous

rate of population change before and after TEDs were introduced.

4 A Generalized Linear Mixed Model

In order to test the robustness of our approach we investigated alternative model formulations. Alternatively, we assumed that the residual variation in the above model was described by

a gamma, as opposed to a lognormal, distribution. For this model, we used a generalized linear

mixed model with a log link and a gamma error distribution. The variation of r among sites was

still considered Gaussian. These parameters were estimated using the generalized linear mixed

model methods developed by Wolfinger and O’Connell (1993).

5 Obtaining an overall estimate of population changes

The above model does not provide an estimate of the total population change over time. One

approach can be used if trend data is available for all sites, though at some sites very limited data

229
might be available. In this case we can include all reliable data and obtain predictions (BLUP)

from a mixed model for each site and year.

6 Data

6.1 Loggerheads

We used data from beach surveys of nesting. We have limited our analysis to beaches where

we believe the effort has been relatively constant over time by including only the years where

consistent length of beach was surveyed and survey start dates were similar (within a two week

time period). However, for Georgia this information was not available and the assumption of

consistent effort may not always be true, particularly for the early years. We view this as the

greatest uncertainty in the analysis. The loggerhead nesting data has been divided into two groups,

the northern subpopulation and the southern subpopulation. The northern subpopulation includes

the beachesin North Carolina, South Carolina, Georgia, and northern Florida. We combined results

for two different time periods: 1979-1999 and 1989-1999. We believe that the data from the more

recent period are more consistent. The following table shows the beaches that are included in the

analysis.

230
Subpopulation State Beach Distance surveyed Date of first survey

northern North Carolina Cape Lookout National Seashore ? ?

northern North Carolina Bald Head Island Conservancy 15 miles 5/15

northern North Carolina Hammocks Beach State Park 3 miles 5/15

northern North Carolina Camp Lejeune Marine Base 6.8 miles 5/24

northern South Carolina Cape Island ? ?

northern Georgia Blackbeard Island ? ?

northern Georgia Cumberland Island ? ?

northern Georgia Jekyll Island ? ?

northern Georgia Little Cumberland Island ? ?

northern Georgia Little St. Simons Island ? ?

northern Georgia Tybee Island ? ?

northern Georgia Ossabaw Island ? ?

northern Georgia Pine Island ? ?

northern Georgia Sapelo Island ? ?

northern Georgia St. Catherine’s Island ? ?

northern Georgia Sea Island ? ?

northern Georgia St. Simons Island ? ?

northern Georgia Wassaw Island ? ?

northern Florida Flagler Co. 24.1 km 4/25-5/1

northern Florida Washington Oaks 1.1-1.2 km 5/1

northern Florida Anastasia SRA 7.2 km 5/1

northern Florida Fort Mantanzas NM 11.2-11.3 km 5/14-5/27

northern Florida Ponte Vedra S 23.6 km 4/28-5/10

northern Florida Guana River SP 6.7-6.8 km 5/1-5/15

northern Florida Amelia Island 14.4-14.5 km 5/1

northern Florida Ft Clinch SP 3.7 km 5/1

southern Florida Hutchinson Island 36.5 km 4/10-4/24

southern Florida Broward Co. Beaches 34.7 km 3/1

southern Florida J.U. Lloyd SRA 3.9 km 4/20-4/30

southern Florida Boca Raton Beaches 8.0 km 3/1

southern Florida MacArthur SP 2.9 km 3/1-3/10

southern Florida Casey Key 11.8 km 5/1

southern Florida Siesta Key 9.0 km 5/1

A negative correlation was found between abundance and date of first nest for Cape Hatteras

National Seashore, North Carolina and Pea Island National Wildlife Refuge, North Carolina. These

beaches were left out of the analysis. Cape Lookout National Seashore, North Carolina is believed

to be standardized after 1990 so this beach was included even though there is no distance surveyed

or first date of survey. For one of the Georgia beaches, Little Cumberland Island, there has been a

large amount of beach erosion. We decided to keep this beach in the analysis because this represents natural variation among beaches, and the turtles from that beach probably nested elsewhere

in the region. A second analysis was performed for the northern subpopulation leaving out the

231
Georgia beaches because the reliability of that information is not known at this time.

6.2 Leatherbacks

Distance of beach covered and survey start date were known for some of the beaches observed

for leatherback nesting. Again, we tried to use only the years with consistent coverage. The data

were separated into three areas for analysis because the overall trends differed for these three areas.

These areas are: South America, St. Croix (US Virgin Islands), and Florida. For Florida we have

limited our analysis to beaches where we believe the effort has been relatively constant over time

by including only the years where consistent length of beach was surveyed and survey start dates

were similar (within a two week time period). However, for South America and the US Virgin

Islands this information was not available and the assumption of consistent effort may not always

be true, particularly for the early years. The following table shows the beaches that are included.

Area Beach Distance surveyed Date of first survey

Florida Hutchinson Island 36.5 km 4/8-4/18

Florida Jupiter/Juno Beach 9.6 km 2/15-3/1

Florida Jupiter Island 13.7 km 3/1-3/3

Florida MacArthur SP 2.9 km 3/1

Florida Highland Beach 4.8 km 4/1-4/15

Florida Broward Co. Beaches 34.7 km 3/1

Florida S Brevard Beaches 40.5 km 4/26-5/8

S. America Yalimapo, French Guiana ? ?

S. America Galibi, Suriname ? ?

S. America Matapica, Suriname ? ?

US Virgin Islands St. Croix ? ?

7 Results

We fit a variety of models to each data set: with lognormal, gamma, or extra-Poisson variability

in the observation error, with separate error variances for each beach, and with and without outliers.

We found that there was relatively little difference among these models fits, but that the separate

error variance was usually needed. For simplicity we will report the lognormal error with separate

error variances as our primary estimates.

7.1 Loggerheads

7.1.1 Georgia

As an example, we first consider the beaches in Georgia individually from 1979-1999. The

estimates of the slope if each nesting site is fit individually by OLS regression are:

232
Nesting Parameter Standard T for H0:

Site Estimate Error Parameter=0 Prob > |T|

BKB 0.005577 0.01366527 0.408 0.6878

CUM 0.007004 0.01254062 0.559 0.5860

JEK 0.015879 0.01160858 1.368 0.1903

LCI -0.092834 0.00900179 -10.313 0.0001

LSI 0.041901 0.03072965 1.364 0.2026

OSS 0.017643 0.01747988 1.009 0.3270

PIN -0.011962 0.03620422 -0.330 0.7473

SAP 0.057755 0.02783523 2.075 0.0622

SCI -0.011230 0.01948592 -0.576 0.5760

SEA 0.073510 0.04804723 1.530 0.1604

SSI -0.192613 0.06439019 -2.991 0.0152

TYB -0.001411 0.08965388 -0.016 0.9878

WAS 0.024396 0.01453494 1.678 0.1096

Note that there are two nominally significant declines (LCI and SSI), but 8 of the 13 slopes are

positive.

We now consider the mixed model results. The estimate for the mean instantaneous rate of

change, μ, was 0 

003 (s.e. = 0.015). The standard deviation of r among sites, σr, was estimated

to be 0.04, and the standard deviation of the error, σ, was estimated to be 0.43.

If we allowed separate error variances for each site, μ is estimated to be slightly positive (μˆ 

0 002, s.e. = 0.01), and with less variation among sites (σˆr 0 03).

Similar results were obtained for the time period from 1989 to 1999 when the nesting data is

believed to be more reliable, i.e. there was no evidence of an overall change in the populations in

Georgia.

7.1.2 Northern US population

In this analysis we fit the data from 1978-1989 with one “r” and the data after with a second “r”

(r 	 ) using a piecewise linear model. In the results below, the “r” for the early period is estimated,

then the change in “r” is added on, all in the same mixed model.

error separate year estimate se pred df

error

variance

lognormal no 
 1978 r 0  026 0.015 25

lognormal no 
 1989 r  0  054 0.022 18

lognormal yes 
 1978 r 0  030 0.012 25

lognormal yes 
 1989 r   0  059 0.017 18

233
The effect of the mixed model analysis for the northern US loggerhead populations is clear

when examining the data (Fig. 1). Each point in the plot represents the number of log transformed

nests. Note that when there are outliers, the mixed model fits downweight these outliers.

• • •

• •

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Cape Lookout National Seashore 

Year 

Log Number of Nests

•

• • ••

•

• •

•

•

•

•

• •

•

•

•

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Hammock’s Beach State Park

Year 

Log Number of Nests

• •

•

•

•

•

• •

•

•

•

• •

•

•

•

•

•

•

• •

1980 1985 1990 1995 2000

0

2

4

6

Camp Lejeune Marine Base 

Year 

Log Number of Nests

•

• •

•

• •

•

•

• •

• •

•

•

•

• •

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Bald Head Island Conservancy

Year 

Log Number of Nests

•

•

• •

•

•

•

•

•

•

•

•

• •

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Cape Island 

Year 

Log Number of Nests

• • •

•

•

•

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Tybee Island 

Year 

Log Number of Nests

• •

• • •

• •

•

•

• •

•

• •

•

•

•

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Wassaw Island 

Year 

Log Number of Nests

•

•

•

•

•

•

•

•

•

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Pine Island

Year 

Log Number of Nests

234
•

•

• • • ••

•

•

•

•

•

•

•

•

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Ossabaw Island 

Year 

Log Number of Nests

•

•

•

•

•

•

•

•

• •

• •

•

1980 1985 1990 1995 2000

0

2

4

6

St. Catherine’s Island 

Year 

Log Number of Nests

•

•

•

•

•

• •

•

• •

•

• •

•

•

•

•

•

•

• •

1980 1985 1990 1995 2000

0

2

4

6

Blackbeard Island

Year 

Log Number of Nests

•

•

•

•

•

•

•

•

•

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Sapelo Island 

Year 

Log Number of Nests

•

•

•

•

•

• •

• •

•

•

1980 1985 1990 1995 2000

0

2

4

6

Sea Island 

Year 

Log Number of Nests

• •

•

•

•

•

•

•

•

• • •

1980 1985 1990 1995 2000

0

2

4

6

Little St. Simons Island

Year 

Log Number of Nests

•

• •

•

•

•

•

• •

•

1980 1985 1990 1995 2000

0

2

4

6

St. Simons Island 

Year 

Log Number of Nests

• •

•

•

•

•

•

•

•

•

•

•

•

• • •

•

•

1980 1985 1990 1995 2000

0

2

4

6

Jekyll Island 

Year 

Log Number of Nests

235
•

•

• •

• •

• •

• • •

•

•

• •

•

•

• • •

•

1980 1985 1990 1995 2000

0

2

4

6

Little Cumberland Island

Year 

Log Number of Nests

•

• • • •

• • •

•

•

• • •

• •

1980 1985 1990 1995 2000

0

2

4

6

Cumberland Island 

Year 

Log Number of Nests

•

•

• •

•

• •

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Ft Clinch SP - Nassau County

Year 

Log Number of Nests

•

•

•

•

•

•

•

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Amelia Island - Nassau County 

Year 

Log Number of Nests

•

•

•

•

•

•

•

• •

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Guana River SP - St. John’s County 

Year 

Log Number of Nests

•

• •

•

• •

•

1980 1985 1990 1995 2000

0

2

4

6

Ponte Vedra S - St. John’s County

Year 

Log Number of Nests

•

•

•

• • •

•

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Anastasia SRA - Flagler County 

Year 

Log Number of Nests

•

•

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Fort Mantanzas NM - St. John’s County

Year 

Log Number of Nests

236
•

• •

•

•

•

•

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Washington Oaks - Flagler County 

Year 

Log Number of Nests

• •

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

Flagler Co. Beaches - Flagler County

Year 

Log Number of Nests

Figure 1: Plots of log transformed nest counts for the beaches in the northern US subpopulation of loggerhead turtles.

Each point is an observation, the solid line is the ordinary least squares fit, and the dashed line is the BLUP from the

mixed model. The mixed model fits come from a model that assumes a separate error variance for each beach. The

vertical dashed line marks the year that TEDs were first employed.

The upshot is: either no change or a decrease from 1978 to 1989 (depending on which model

you consider), and a probable increase from 1989 to 1999. The magnitude and statistical significance of the increase depends upon the exact implementation of the model, but the effect is

suggestive in all analyses.

237
7.1.3 Northern US population - Georgia not included

One problem with the analysis of the northern US population is that the reliablity of the data

from Georgia is not known. The other sites had both distance of beach surveyed and the start date

of the survey, information that was missing from the Georgia data. To assess the robustness of the

previous results we fit the same model as before, but this time omitted the Georgia sites from the

analysis.

error separate year estimate se pred df

error

variance

lognormal no 
 1978 r 0  002 0.026 12

lognormal no 
 1989 r  0  049 0.034 7

lognormal yes 
 1978 r 0  011 0.019 12

lognormal yes 
 1989 r  0  048 0.028 7

When Georgia is left out of the analysis the parameter estimates obtained are similar, resulting

in similar trends, but these results are no longer statistically significant.

7.1.4 South Florida Loggerheads

The results for the south Florida loggerheads are:

error separate year estimate se pred df

error

variance

lognormal no 
 1978 r  0  054 0.022 6

lognormal no 
 1989 r 0  011 0.028 1

lognormal yes 
 1978 r  0  055 0.014 6

lognormal yes 
 1989 r 0  015 0.021 1

In summary, for south Florida the model with the separate error variances for each beach, the

population has been growing with a rˆ 0 054 (s.e. 0.022) since 1979. When an additional term is

added for the period since 1989, there is not a significant change (r 	 is estimated to be -0.011 (s.e.

0.028)). Note that the direction of change is the opposite sign as for the northern population.

238
•

• •

• • • •

• • • •

•

•

• •

1980 1985 1990 1995 2000

0

2

4

6

8

Hutchinson Island

• •

•

• • • • •

1980 1985 1990 1995 2000

0

2

4

6

8

MacArthur SP

•

• •

•

• •

1980 1985 1990 1995 2000

0

2

4

6

8

Boca Raton Beaches

•

•

• •

1980 1985 1990 1995 2000

0

2

4

6

8

Broward Co. Beaches

•

•

•

• •

•

•

1980 1985 1990 1995 2000

0

2

4

6

8

J.U. Lloyd SRA 

•

•

•

•

•

•

•

• • •

1980 1985 1990 1995 2000

0

2

4

6

8

Siesta Key !

•

•

•

•

•

• • • •

1980 1985 1990 1995 2000

0

2

4

6

8

Casey Key 

Year 

Log Number of Nests

Figure 2: Plots of log transformed nest counts for the beaches in the southern US subpopulation of loggerhead turtles.

Each point is an observation, the solid line is the ordinary least squares fit, and the dashed line is the BLUP from the

mixed model. The mixed model fits come from a model that assumes a common error variance among beaches. The

vertical dashed line marks the year that TEDs were first employed.

We also display the estimated total number for the northern and southern populations of loggerhead for the surveyed beaches (Fig. 3). In these plots, we summed the predicted numbers in

the individual regressions and the mixed models estimates to estimate the total number in the areas

surveyed.

239
•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

1980 1990

2400 "

2600 "

2800 "

3000

3200

3400

3600

Mixed

•

•

•

•

•

•

•

•

• •

•

•

•

•

•

•

•

•

•

•

•

1980 1990

2400 "

2600 "

2800 "

3000

3200

3400

3600

Individual

Northern US Subpopulation

Number of Nests in Surveyed Areas

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

1980 1990

6000

8000

10000

12000

Mixed

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

1980 1990

6000

8000

10000

12000

Individual

Southern US Subpopulation

Year #

Figure 3: Plots of predicted nest counts for the beaches in the northern and southern US subpopulation of loggerhead

turtles. The individual estimates are from the sum of the individual OLS regressions, and the mixed model estimates

are from the sum of the Best Linear Unbiased Predictors for each beach.

7.2 Leatherbacks

For leatherbacks we treated the data from the Virgin Islands, South America, and Florida as

separate groups, or populations. For the Virgin Islands and Florida we examined data from 1979

on, but used data from 1987 on for South America because of changes in local fishing policy.

For the US Virgin Island site, we carried out a simple linear regression on the log transformed

nests to estimate the instantaneous rate of population change. The estimate was 0.078 (s.e.= 0.014).

For the Florida sites,

240
error separate estimate se pred df

error

variance

lognormal no r  0  118 0.056 6

lognormal yes r  0  109 0.019 6

Poisson no r  0  095 0.049 6

Poisson yes r  0  107 0.059 6

gamma no r  0  122 0.053 6

gamma yes r  0  117 0.052 6

•

•

• •

1980 1985 1990 1995 2000

0

2

4

6

8

10

Broward Co. Beaches

•

• •

•

• • •

1980 1985 1990 1995 2000

0

2

4

6

8

10

Highland Beach

•

•

•

• •

•

•

• • •

•

• •

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

8

10

Hutchinson Island

•

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

8

10

Jupiter Island 

•

•

•

•

• •

•

1980 1985 1990 1995 2000

0

2

4

6

8

10

Jupiter/Juno Beach 

• • • •

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

8

10

MacArthur SP

•

• •

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

8

10

S. Brevard Beaches !

Year 

Log Number of Nests

Figure 4: Plots of log transformed nest counts for the beaches in the Florida population of leatherback turtles. Each

point is an observation, the solid line is the ordinary least squares fit, and the dashed line is the BLUP from the mixed

model. The mixed model fits come from a model that assumes a common error variance among beaches.

241
For South America,

error separate estimate se pred df

error

variance

lognormal no r 0  190 0.060 2

lognormal yes r 0  163 0.041 2

•

•

•

•

•

•

•

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

8

10

Yalimapo, French Guiana $

•

• •

•

1980 1985 1990 1995 2000

0

2

4

6

8

10

Galibi, Suriname %

•

• •

•

•

•

1980 1985 1990 1995 2000

0

2

4

6

8

10

Matapica, Suriname

Year 

Log Number of Nests

Figure 5: Plots of log transformed nest counts for the beaches in the South American population of leatherback

turtles. Each point is an observation, the solid line is the ordinary least squares fit, and the dashed line is the BLUP

from the mixed model. The mixed model fits come from a model that assumes a common error variance among

beaches.

242
We also display the estimated total number for the northern and southern populations of loggerhead for the surveyed beaches (Fig. 6). In these plots, we summed the predicted numbers in

the individual regressions and the mixed models estimates to estimate the total number in the areas

surveyed.

• • • •

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

1985 1990 1995

50&

100

150

200 "

250 "

Mixed

• •

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

1985 1990 1995

50&

100

150

200 "

250 "

Individual

Florida

Number of Nests in Surveyed Areas

•

•

•

•

•

•

•

•

•

•

•

•

1988 1992 1996

10000

20000 "

30000

40000 '

50000 &

Mixed

•

•

•

•

•

•

•

•

•

•

•

•

1988 1992 1996

10000

20000 "

30000

40000 '

50000 &

Individual

South America

Year #

Figure 6: Plots of predicted nest counts for the beaches in the Florida and South America subpopulation of

leatherback turtles. The individual estimates are from the sum of the individual OLS regressions, and the mixed

model estimates are from the sum of the Best Linear Unbiased Predictors for each beach.

7.3 Limitations of the analysis

This study was limited by the inability to access the raw data to assess day by day counts and

effort. Future analyses would be much more reliable if such data was made available.

243
7.4 Acknowledgements

We would like to acknowledge all the individuals and organizations that collected and contributed data that made this analysis possible. Melissa Snover and Lisa Csuzdi provided the nesting

beach data. For Georgia we would like to thank Mark Dodd of the Georgia Department of Natural Resources, Jim Richardson for Little Cumberland Island, Jekyll Island Sea Turtle Project for

Jekyll Island, The Lodge on Little St. Simon’s Island, Georgia Department of Natural Resources

for Sapelo Island and Ossabaw Island, Savanna Coastal refuges and the U.S. Fish and Wildlife

Service for Blackbeard Island, the Caretta Research Project and the U.S. Fish and Wildlife Service

for Wassaw Island and Pine Island, and the National Park Service for Cumberland Island. For

North Carolina we would like to thank Ruth Boettcher of the North Carolina Department of Natural Resources, the North Carolina Wildlife Resources Commission, Sea Turtle Activities at Cape

Hatteras National Seashore for Cape Hatteras National Seashore, North Carolina Division of Parks

and Recreation and the Department of Environment and Natural Resources for Hammock’s Beach

State Park, University of North Carolina - Wilmington and the Bald Head Island Conservancy,

U.S. Fish and Wildlife Service for Pea Island National Wildlife Refuge, and the Emerald Island

Volunteer Program for Bogues Bank. Cape Romain National Wildlife Refuge provided the data

for Cape Island. The Florida Fish and Wildlife Commission provided the Florida data. A special

thank you to all the volunteers contributing to the nesting beach studies over the years.

References

Hedges, L. V., and Olkin, I. 1980. Vote-counting methods in research synthesis. Psychological

Bulletin 88: 359–369.

Hedges, L. V., and Olkin, I. 1985. Statistical Methods for Meta-analysis. Academic Press, San

Diego.

Searle, S. R., Casella, G., and McCulloch, C. E. 1992. Variance Components. John Wiley and

Sons, New York, NY.

Wolfinger, R., and O’Connell, M. 1993. Generalized linear mixed models: a pseudo-likelihood

approach. J. Statist. Comput. Simul. 48: 233–243.

244
APPENDIX 2

SUMMARY OF OBSERVED, ESTIMATED,

INCIDENTAL, (LETHAL), AND [STRANDINGS]

TAKE LEVELS, SEA TURTLE LIFE STAGE,

GEOGRAPHIC REGION OF ACTIVITY, AND

REFERENCE FOR PERMITTED AND NONPERMITTED SPECIFIC AND GENERALIZED

ACTIVITIES IMPACTING SEA TURTLES IN

THE U.S. ATLANTIC, CARIBBEAN, AND GULF

OF MEXICO

Joanne Braun-McNeill

Wayne Witzell
246

APPENDIX 2.

Table 1. Summary of observed, estimated, incidental, (lethal), and [strandings] take levels, sea turtle life stage, geographic region of activity and reference for permitted and non-permitted

specific activities in the U.S. Atlantic, Caribbean and Gulf of Mexico.

Annual Observed, Estimated, Incidental (Lethal ) and [Strandings] Take Levels 1

Loggerhead Leatherback Green Kemp’s Hawksbill Olive Ridley

Life Stage

Geographic

Region Reference

 Federal Permitted Activities - NMFS

Coast Guard Vessel Operation 1(1)21(1)

2

1(1)

2

1(1)

2

1(1)

2

0 Adult, Immature Atlantic NMFS 1995a, 1996b,

1998b

Navy – SE Ops Area391(91) 17(17)

2

16(16)216(16)

2

4(4)20 Adult, Immature Atlantic, Gulf of

Mexico

NMFS 1997b

Navy-NE Ops Area 10(10) 0 1(1)21(1)

2

0 0 Adult, Immature N. Atlantic NMFS 1996f

Shipshock – Seawolf/Winston Churchill4276(58)2276(58)2276(58)2276(58)2276(58)20 Adult, Immature Atlantic coast of

Florida

NMFS 1996c

COE Dredging-NE Atlantic 29(29) 2(2) 7(7)26(6)20 0 Adult, Immature NE Atlantic NMFS 1998i, NMFS

1998j,

NMFS 2000g

COE Dredging – S. Atlantic 35(35) 0 7(7) 7(7) 2(2) 0 Adult, Immature S. Atlantic NMFS 1997f

COE Dredging - N & W Gulf of Mexico 30(30) 0 8(8) 14(14) 2(2) 0 Adult, Immature N&W Gulf of

Mexico

NMFS 1998k

COE Dredging - E Gulf of Mexico 8 (8) 5 5(5)55(5)55(5)55(5)50 Adult, Immature E. Gulf of

Mexico

NMFS 1996g

COE Rig Removal, Gulf of Mexico 1(1)21(1)21(1)21(1)21(1)20 Adult, Immature Gulf of Mexico NMFS 1997g

Wilmington Harbor Project - Blasting 1(1) 1(1) 1(1) 1(1) 1(1) 0 Adult, Benthic

immature

8/1 - 1/31

New Hanover &

Brunswick Co,

NC

NMFS 2000f

Wilmington Harbor Project - Gill nets undeterm. undeterm. undeterm. undeterm. undeterm. 0 Adult, Benthic

immature

8/1 - 1/31

New Hanover &

Brunswick Co,

NC

NMFS 2000f

MMS Destin Dome Lease Sales 1(1)2;61(1)2;61(1)2;61(1)2;61(1)260 Adult, Immature eastern Gulf of

Mexico

NMFS 2000h
247

MMS Rig Removal, Gulf of Mexico 10(10)75(5)2;75(5)2;75(5)2;75(5)2;70 Adult, Immature Gulf of Mexico NMFS 1988, NMFS

1998l

NE Multispecies Sink Gillnet Fishery 10(10) 4(4) 4(4) 2(2) 0 0 Adult, Immature Gulf of Maine,

mid-Atlantic

NMFS 1989, 1993c,

1996d

NE Observer Program Sink Gillnet Fishery8

0-2(0) 0 0 0 0 0 Adult, Immature NE Atlantic NEFSC unpubl. data

(Richard Merrick9,

Mike Tork10,

personal

communication)

NE Observer Program Bottom Coastal

Gillnet8

1-13(0-7) 0 0-2(0-2) 1-4(1-2) 0 0 Adult, Immature Mid-Atlantic NEFSC unpubl. data

(Richard Merrick 9,

Mike Tork 10,

personal

communication)

NE Observer Program Scallop Dredge80-1(0) 0 0 0 0 0 Adult, Immature Mass-Va. NEFSC unpubl. data

(Richard Merrick 9,

Mike Tork 10,

personal

communication)

ASMFC Lobster Plan 10 (10) 4(4) 0 0 0 0 Adult, Pelagic

immature

Atlantic- MaineNCNMFS 1998c

Bluefish 6(3) 0 0 6(6) 0 0 Adult, Immature Atlantic -

Maine-Florida

NMFS 1999b

Herring 6(3) 1(1) 1(1) 1(1) 0 0 Adult, Immature NE Atlantic NMFS 1999d

Mackerel, Squid, Butterfish 6(3) 1(1) 2(2) 2(2) 0 0 Adult, Immature NE and MidAtlanticNMFS 1999a

Monkfish Fishery76(3) 1(1) 1(1) 1(1) 0 0 Adult, Immature NE and MidAtlanticNMFS 1998d

Dogfish Fishery 6(3) 1(1) 1(1) 1(1) 0 0 Adult, Immature AtlanticMaine-FlNMFS 1999c

Sargassum 30(30)11 1(1)2

1(1)21(1)21(1)20 Adult, Pelagic

immature

Atlantic NMFS 1999i

Summer Flounder, Scup & Black Sea Bass 15(5) 3(3)23(3)23(3)23(3)20 Adult, Immature NE and MidAtlanticNMFS 1996a

Shrimp Fishery 3450(3450) 12 650(650) 12 3450(3450) 12 3450(3450) 12 3450(3450) 12 0 Adult, Immature Atlantic, Gulf of

Mexico

NMFS 1998a
248

NE Observer Program - Otter Trawl 80-1(0) 0 0 0 0 0 Adult, Immature NE and MidAtlanticNEFSC unpubl. data

(Richard Merrick 9,

Mike Tork 10,

personal

communication)

NE Observer Program - Mid-Atlantic

Coastal Trawl 8

3-15(1-4) 0 0 0-2(0) 0 0 Adult, Immature Mid-Atlantic NEFSC unpubl. data

(Richard Merrick 9,

Mike Tork 10,

personal

communication)

Weakfish 20(20) 0 0 2(2) 0 0 Adult, Immature Atlantic NMFS 1997h

HMS - Pelagic Longline Fishery 13 468(7) 358(6) 46(2) 23(1) 46(2) 0 Adult, Immature Atlantic, Gulf of

Mexico

NMFS 2000i

HMS - Pelagic Longline Fishery 14 931(1) 918(0) 0 0 0 0 Adult, Immature Atlantic, Gulf of

Mexico

Yeung et al 2000

NE Observer Program Longline Fishery 88-119(0) 2-45(0) 0-2(0) 0 0 0 Adult, Pelagic

immature

Maine-Florida NEFSC unpubl. data

(Richard Merrick 9 ,

Mike Tork 10 ,

personal

communication)

HMS - Shark gillnet Fishery 15 20(20) 2(2) 2(2) 2(2) 2(2) 0 Adult, Immature Georgia, Florida

coastal waters

NMFS 2000i

NE Observer Program - Pelagic Drift

Gilnet11a

6-35(1-10) 5-27(2-12) 0-2(0-1) 0-1(0-1) 0 0 Adult, Immature Maine-Florida NEFSC unpubl. data

(Richard Merrick 9 ,

Mike Tork 10,

personal

communication)

HMS - Bottom Longline Fishery 15 12(12) 2(2) 2(2) 2(2) 2(2) 0 Adult, Immature Atlantic,

Caribbean, Gulf

of Mexico

NMFS 2000i

HMS - all other gears 15 3(3) 3(3) 3(3) 3(3) 3(3) 0 Adult, Immature Atlantic,

Caribbean, Gulf

of Mexico

NMFS 2000i

NRC – St. Lucie, FL 16 unlimited(2

)

unlimited(1

)

unlimited(3

)

unlimited(1

)

unlimited(1

)

0 Adult, Benthic

immature

Florida NMFS 1997a

NRC – Brunswick, NC 50 (6) 250 250 (3) 250 (2) 250 20 Adult, Benthic

immature

North Carolina NMFS 2000j
249

NRC – Crystal River, FL 55 (1) 255 (1) 255 (1) 255 (1) 255 (1)20 Adult, Benthic

immature

Florida NMFS 1999j

Oyster Creek Nuclear Generating Station 17 10(3) 0 2(1) 3(1) 0 0 Adult, Benthic

immature

New Jersey NMFS 1995b

Salem&Hope Creek Nuclear Generating

Station

30(5) 0 5(2) 5(1) 0 0 Adult, Benthic

immature

New Jersey NMFS 1993a, 1998e

Sneads Ferry Shrimp Trawling, NCDMF 2 - 0 1 - 0 1 - 0 1 - 0 1 - 0 0 Adult, Benthic

immature

Sneads Ferry,

North Carolina

NMFS 1996e

 Permit # 1008

Grays Reef National Marine Sanctuary 30 - 1(0) 0 0 0 0 0 Adult Georgia NMFS 1997c Permit

# 1030

Atlantic, Gulf of Mexico, U.S. Virgin Islands,

Puerto Rico Research

200 -

13(0)

8 - 4(0) 20 - 20(1) 20 - 4(0) 1 - 0 0 Adult Georgia &

Florida

NMFS 1997d

 Permit # 1033

Eastern Atlantic Ocean Research, Dr. Molly

Lutcavage, New England Aquarium

0 8 - 4(0) 0 0 0 0 Adult, Pelagic

immature

Puerto Rico NMFS 1997e Permit

# 1053

Flower Gardens National Marine Sanctuary

Research, Dr. David Owens

15 - 3(0) 0 0 10 - 0 5 - 0 0 Adult Texas NMFS 1998f

 Permit #1106

Galveston Texas Research, Dr. Andre M.

Landry, Jr.

100 - 2(0) 0 150 - 2(0) 200 -

47(0)

20 - 0 0 Adult, Immature Calcasieu &

Sabine Pass, TX

NMFS 1998g

Permit # 1133

Pierce Inlet Indian River Lagoon Research,

Bruce D. Peery and Michael J. Bressette

25 - 13(0) 0 100 -

64(0)

5 - 0 0 0 Adult Florida NMFS 1998h

 Permit # 1144

Northwest Atlantic Ocean, Stepen M.H.

Connett, St. George’s School

50 - 6(0) 0 5 - 81(0) 5 - 0 5 - 37(0) 0 Adult, Immature Bahamas NMFS 1999e

 Permit # 1187

Florida Bay Research, Florida Fish and

Wildlife Conservation Commission

300 -

46(0)

5 - 0 250 - 5(0) 100 - 2(0) 25 - 0 0 Adult, Immature Florida Bay NMFS 1999f

 Permit # 1198

Florida Bay Research,Florida Fish and

Wildlife Conservation Commission

400 -

126(10)

found dead

0 0 0 0 0 Hatchling Florida Bay NMFS 1999f

 Permit # 1198

Alabama Research, Dr. Thane Wibbels 100 - 0 0 100 - 0 50 - 0 0 0 Benthic

immature

Alabama NMFS 1999g

 Permit # 1201

Mosquito Lagoon, Florida Research, Dr. Jane

Provancha

100 - 1(0) 0 100 -

10(0)

0 0 0 Adult, Benthic

immature

Florida NMFS 1999h

 Permit # 1214

Indian River Lagoon Estuary Research, Dr.

Llewellyn M. Ehrhart 18

135 1 600 3 2 0 Adult, Benthic

immature

Florida NMFS 2000a

 Permit # 1231
250

Virgin Islands Research, Dr. Jack Musick,

Virginia Institute of Marine Sciences18

0 5 10 0 20 0 Adult, Immature US Virgin

Islands

NMFS 2000b

 Permit # 1236

Trawling SC to FL Research , J. David

Whitaker, SCDNR 18

200 1 1 23 0 0 Adult, Immature SC to Florida NMFS 2000c

 Permit # 1245

Puerto Rico Research, Carlos Diez,

PRDRNA18

0 0 300 0 300 0 Adult, Benthic

immature

Puerto Rico NMFS 2000d

 Permit # 1253

NC Flounder Gillnet Fishery ITP NCDENR,

DMF 18,19

112 (56)

[14] 8(2)

51.0(7.4)

2(2) 0 72 (36)

[9]

6(3)

93.1(43.5)

192 (96)

[24]

34.5

(28.3)

2 (2) 0 Adult, Benthic

immature

Pamlico Sound,

NC

NMFS 2000e

 Permit # 1259

Federal Permitted Activities - FWS 20

Region 5 (NE) - Beach Nourishment -

Colonel Robert Reardon, COE

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

ACOE Va.

Beach, VA

FWS,1996a

 Beach Nourishment - Ms. Valerie

Hilliard, USN

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

USN - Dam

Neck, VA

FWS,1995a

 Transportation of live stranded, injured -

Ms. Dana Hartley, NE region Stranding

Network coordinator

No Data No Data No Data No Data No Data No Data Adult, Immature ME, Mass,

Conn, NY, NJ,

Del, Md, Va

FWS,1999d

 Holding of turtles for rehabilitation and 

 display purposes- Ms. Dana Hartley,

NE region Stranding Network coordinator

No Data No Data No Data No Data No Data No Data Adult, Immature Mass, Va FWS 1999d

 Tagging of Nesting Females- Ms. Dana

Hartley, NE region Stranding Network

coordinator

1 0 0 0 0 0 Adult Virginia FWS 1999d

Region 4 (SE) - Beach driving

Incidental Take Permit - County of Volusia,

FL

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Volusia Co., Fl FWS,1999i

Permit#TE811813-4

Atlanta Ga field

office

 Collection of blood & tissue samples,

Kathryn Craven, Texas A&M Univ, College

Station, TX

No Data No Data No Data No Data No Data No Data Adult, Immature Florida & Texas FWS 2000m

Texas A&M Permit

#TE025759-0

 Collection of blood & tissue samples - Dr.

Andrew Kemmerer, Regional Administrator,

NMFS, SERO, St. Petersburg, FL

No Data No Data No Data No Data No Data No Data Adult, Immature Va to Fl, Gulf of

Mexico,

Caribbean

FWS 1999j

SEFSC Permit

#TE676379-2
251

 Seismic Surveys

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Breton NWR,

Louisiana

Informal consult.

Debbie Fuller 21

Lafeyette, LA Field

Office

 Beach Nourishment - District Engineer,

Mobile District, COE, Mobile, AL

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

City of Gulf

Shores, AL

FWS 2000n

 Daphne, AL

 Dune restoration - Brett Real Estate,

Robinson Development Co, Inc

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Orange Beach,

AL

FWS 1996c

IT Permit PRT809898 Daphne,AL

 Construction - Brett Real Estate,

Robinson Development Co, Inc

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Orange Beach,

AL

FWS 1996c

 IT Permit PRT809898 Daphne, AL

 Emergency berm - District Engineer,

Mobile District, COE, Mobile, AL

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

south shore of

Dauphin Island,

Mobile Co., AL

FWS 2000o

Daphne, AL

 Coast of Florida Study - Beach

Nourishment - Colonel Terry Rice, COE

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

27 projects

spanning 93 km

in Palm Beach,

Broward &

Dade Co, Fl

FWS 1996b

 Vero Beach, FL

 Coast of Florida Study amendment- 63rd

Street Beach Nourishment-James Duck,

COE

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

0.5 mile of

beach, MiamiDade Co, Fl

FWS 2000d

Log# 4-1-00-F-701 

Vero Beach, FL

 Coast of Florida Study amendment- South

Palm Beach Island Nourishment-Bryce

McCoy, Project Manager, COE

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

1.9 mile of

beach, Palm

Beach Co, Fl

FWS 2000e

Log# 4-1-00-F-497 

Vero Beach, FL

 Coast of Florida Study amendmentJupiter Inlet deposition of dredge spoil-Bryce

McCoy, Project Manager, COE

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

beach south of

Jupiter Inlet,

Palm Beach Co,

Fl

FWS 2000c

Log# 4-1-00-I-233 

Vero Beach, FL

 Lido Beach Shore Project - 

 renourishment-Colonel Joe Miller, COE

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

3,600 ft on Lido

Key, Sarasota

Co, Fl

 FWS 2000f

Log# 4-1-99-F-252 

 Vero Beach, FL

 Lighthouse Point Beach Groin

Construction-Colonel Joe Miller, COE

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Sarasota Co, FL FWS 2000g

Log# 4-1-99-F-99

Vero Beach, FL
252

 Fisher Island deposition of dredge spoilColonel Joe Miller, COENo Data No Data No Data No Data No Data No Data Adult &

Hatchling

0.168 km Fisher

Island, MiamiDade Co, Fl

FWS 1999f

Log# 4-1-98-F-643

Vero Beach, FL

 Lee County Shore Project - nourishment -

Colonel Joe Miller, COE

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

11.7 km in Lee

County, Fl

 FWS 1999g

Log# 4-1-99-F-812

Vero Beach, FL

 US MMS-Central Gulf of Mexico Lease 

 Sales-Assoc. Director for Offshore Leasing,

MMS

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Central Gulf of

Mexico nesting

beaches

FWS 1997

Log# 4-P-97-075

Panama City, Fl

 US MMS-Eastern Gulf of Mexico 

 Lease-develop, produce and transport

natural gas from the Destin Dome 56 Unit to

Alabama near Mobile - Regional Dir. MMS,

New Orleans, LA

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Eastern Gulf of

Mexico nesting

beaches

FWS 2000h

Log# 4-P-00-003

Panama City, Fl

 Beachfront construction-artificial 

lighting - Deputy Regional Director, FWS

Atlanta, GA

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

427m of Gulf of

Mexico

beachfront

FWS 2000i

June 8, 2000

Panama City, FL

 FEMA Emergency Berm - Mr. Brett

Bowen, FEMA, Atlanta, GA

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

May 1-19

24, 125 linear ft

Okaloosa Co, Fl

 FWS 2000j

Log# 4-P-00-102

Panama City, FL

 FEMA Emergency Berm - Mr. Brett

Bowen, FEMA, Atlanta, GA

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

May 1-15

24,000 linear ft.

Cape San

Blas/St. Joseph

Peninsula, Gulf

Co, Fl

 FWS 2000k

Log# 4-P-00-103

Panama City, FL

 Deposition of dredged material - Mr. J.

Tracy Howell, South Walton Tourist

Development Council

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Miramar Beach,

Walton Co, Fl

FWS 2000l

Log# 4-P-00-144

Panama City, FL

 Panama City Beach Nourishment -

Colonel Joe Miller, COE

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

27 km of

Panama Beach,

Bay Co, Fl

FWS 1998g

Log# 4-P-97-108

Panama City, FL

 Theater Missile Defense systems testing 

 -vehicles and lights on beach - US Air Force

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Eglin Air Force

Base at Cape

San Blas and

Santa Rosa

Island, Fl

FWS 1999h

 Panama City, FL
253

 Tyndall Air Force Base - driving on 

 beach - Brigadier General Gary Rubus,

US Air Force

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Tyndell AFB

beachfront

(20.6km)

Bay Co, Fl

 FWS 1998e

Log# 4-P-98-020

Panama City, FL

 Lake Powell Outlet excavation - Colonel

Joe Miller, COE

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

1500 ft beach

front, Camp

Helen,

Bay Co, Fl

 FWS 1998f

Log# 4-P-97-089

Panama City, FL

 Renourishment No Data No Data No Data No Data No Data No Data Adult &

Hatchling

22 miles

Brevard Co Fl

Don Palmer 22

Jacksonville Office,

FL

 Renourishment No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Patrick Air

Force Base, FL

 Don Palmer 22

Jacksonville Office,

FL

 ACOE revetment on beach No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Glynn Co.,

Georgia

FWS 1992

Log#4-4-93-032

Athens, Ga.

 ACOE beach nourishment, breakwater, 

 groin

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Glynn Co.,

Georgia

FWS 1995b

Log#4-4-95-071

Athens, Ga.

 Wilmington Harbor Project - 

 nourishment- Colonel James

DeLony, COE

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Carolina Beach

to Holden

Beach, NC

FWS 2000b

Raleigh, NC

 Wilmington Harbor Project - deposition 

 of dredged material

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Bald Head

Island &

Caswell Beach,

NC

FWS 2000b

Raleigh, NC

 Deposition of dredged material on Nags

Head- Colonel James DeLony, COE

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

Nags Head and

South Nags

Head, NC

FWS 1999e

Raleigh, NC

 Naval training exercises - Rear Admiral

J.K. Moran, Commander Navy Region

Southeast, Naval Air Station, Jacksonville, Fl,

32212

No Data No Data No Data No Data No Data No Data Adult &

Hatchling

eastern end of

Vieques Island,

PR

FWS 2000p

Boqueron Field

Office

 Construction of buildings-Mr. William V.

Mailloux, Culebra Northshore,SE

0 2 0 0 2 0 Adult &

Hatchling

Tortola beach,

Culebra Island, 

PR

FWS 2000q

Incidental Take

Permit# TE026114
254

Region 2 (SW) - Transport and 

 rehabilitation of injured sea turtlesMr. Anthony Amos, Univ. Texas at Austin

No Data No Data No Data No Data No Data No Data Adult, Immature Gulf coast of

Texas

FWS 1999b

Permit#TE30177-0

Albuquerque, NM

 Transport and rehabilitation of injured 

 sea turtles - Donna Shaver-Miller

20 0 50 50 30 0 Adult, Immature Padre Island

Nat’l Seashore,

TX

FWS 2000a

Permit#TE840727-0

Albuquerque, NM

 Flipper tagging females - Donna ShaverMiller10 10 10 30 10 0 Adult Padre Island

Nat’l Seashore,

TX

FWS 2000a

Permit#TE840727-0

Albuquerque, NM

 Incubation of eggs and release of 

surviving hatchlings - Donna Shaver-Miller23

1000(10) 400(10) 1000(10) 4000(10) 400(10) 0 Hatchling Padre Island

Nat’l Seashore,

TX

FWS 2000a

Permit#TE840727-0

Albuquerque, NM

 Netting of juveniles - Donna ShaverMiller0 0 150 0 5 0 Benthic

immature

Mansfield

Channel, TX

FWS 2000a

Permit#TE840727-0

Albuquerque, NM

 Satellite tagging females - Donna ShaverMiller0 0 0 6 0 0 Adult Padre Island

Nat’l Seashore,

TX

FWS 2000a

Permit#TE840727-0

Albuquerque, NM

 Attachment of sonic/radio tags, 

 ultrasound and laparoscopic procedures -

Dr. Andre Landry

200 0 300 200 20 0 Benthic

immature

Gulf coast of

Texas

FWS 1999a

Permit#TE776123-0

Albuquerque, NM

 MMS OCS oil and gas lease sales No Data No Data No Data No Data No Data No Data Adult, Immature Gulf of Mexico

Western

Planning area

FWS 1998a

 Seismic survey work - Mr. Phil Martin

Legal Services/NRDA Section, Texas

General Land Office, Austin, TX 24

No Data No Data No Data No Data No Data No Data Adult, Immature Coastal public

land in Redfish,

Aransas, Corpus

Christi Bays,

Texas

FWS 1998c

 Seismic survey work- Mr. Phil Martin,

Legal Services/NRDA Section, Texas

General Land Office, Austin, TX 24

No Data No Data No Data No Data No Data No Data Adult, Immature Laguna Madre,

Baffin Bay, Gulf

of Mexico in

Kleberg &

Kenedy Co, TX

FWS 1999c

 Seismic survey work - Mr. Phil Martin

Legal Services/NRDA Section, Texas

General Land Office, Austin, TX 24

No Data No Data No Data No Data No Data No Data Adult, Immature Laguna Madre

& Corpus Christi

Bay, Nueces &

Kleberg Co, TX

FWS 1998d
255

 Seismic survey work - Mr. Richard P.

Courtemanche, Jr., Project Scientist

Coastal Environments, Inc., Baton Rouge,

LA 24

No Data No Data No Data No Data No Data No Data Adult, Immature Padre Island in

Nueces &

Kleberg, Co,

Texas

FWS 1998b

State Permitted Activities

N. Carolina - Tagging of Nesting Females:

John Townsend, Camp Lejeune; D. Webster,

UNC; K. Rittmaster, NC Maritime Museum;

S. Bland, Hammocks Beach SP; George

Baird, CP&L

No Data No Data No Data No Data No Data No Data Adult N. Carolina NCWRC

(Ruth Boettcher 

personal

communication 25)

 Relocation of Turtle Nests: Pea Island

National Wildlife Refuge; NC National

Estuarine Research ; ACOE; Cape Lookout

National Seashore; Cape Hatteras National

Seashore; Mackay Island NWR; Oak Island

Sea Turtle Project; Ocean Isle Sea Turtle

Program; Caswell Beach Turtle Program;

Sunset Beach Sea Turtle Project; Holden

Beach Turtle Watch Program; Town of

Emerald Isle; Wrightsville Beach Turtle

Project; Topsail Sea Turtle Project; Atlantic

Beach Sea Turtle Project; Pine Knoll Shores

Sea Turtle Project; Carolina/Kure Bch. Sea

Turtle Project; Figure Eight Sea Turtle

Project; Emerald Isle Turtle Trotters;

Network for Endangered Sea Turtles;

Campbell University; John Townsend Camp

Lejeune; D. Webster, UNC; K. Rittmaster,

NC Maritime Museum; Hammocks Beach

SP; Fort Fisher Recreation Area; Fort Macon

State Park

No Data No Data No Data No Data No Data No Data Hatchling N. Carolina NCWRC

(Ruth Boettcher,

personal

communication 25)

 Clinical Trials - Craig A. Harms, D.V.M.,

Ph.D.

No Data No Data No Data No Data No Data No Data Immature N. Carolina NCWRC

(Ruth Boettcher,

personal

communication 25)
256

 Treatment of injured sea turtles: Claire F.

Hohenwarter, DVM; Mary Burkhart, DVM;

Bill Rabon, DVM; Dr. Michael Stoskopf,

DVM; Christy Redfearn, DVM; Karen

Beasley Sea Turtle Rescue and

Rehabilitation Center; Cathy Kreis, DVM;

Craig A. Harms, D.V.M., Ph.D.

No Data No Data No Data No Data No Data No Data Adult, Immature N. Carolina NCWRC

(Ruth Boettcher,

personal

communication25)
257

 Transportation/possession of live turtles:

Preston P. Pate, Jr., NCDMF; John

Townsend Camp Lejeune; Donald

Hoss,NMFS; D. Webster, UNC; K.

Rittmaster, NC Maritime Museum; 

Hammocks Beach SP; Fort Macon State

Park; Fort Fisher Recreation Area;

Discovery Place, Inc.; Claire F.

Hohenwarter, DVM; George Baird, CP&L;

Ocean Isle Museum of Coastal Carolina;

Natural Science Center of Greensboro; Ken

Lohmann, UNC; William F. Shaw; Larry

Crowder, Duke Marine Lab; Jennifer Keller,

Duke Marine Lab; Pea Island National

Wildlife Refuge; NC National Estuarine

Research; ACOE; Cape Lookout National

Seashore; Cape Hatteras National Seashore;

Mackay Island NWR; Oak Island Sea Turtle

Project; Ocean Isle Sea Turtle Program;

Caswell Beach Turtle Program; Sunset

Beach Sea Turtle Project; Holden Beach

Turtle Watch Program; Town of Emerald

Isle; Wrightsville Beach Turtle Project;

Topsail Sea Turtle Project; Atlantic Beach

Sea Turtle Project; Pine Knoll Shores Sea

Turtle Project; Carolina/Kure Bch. Sea

Turtle Project; Figure Eight Sea Turtle

Project; Emerald Isle Turtle Trotters;

Network for Endangered Sea Turtles;

Campbell University; Kristy Long; Jockey

Ridge State Park; Pricey T. Harrison;

Richard Metz; Hatteras Rescue Squad; Brad

Colaw; Cape Fear River Watch; Jackie 

Harris ; Jeannine S. Gurganus; Martha Pat

Garber; Kim Horstman; Phil and Jacob

Kouwe; Ron Metz; William A. McLellan;

John Henderson; Barrier Island Kayaks;

David L. Frum; Bill Vancura; Dee and Larry

Hardham; Ralph Barile; Ray Midgett; Sidney

Maddock; Kenny and Carisa Marshall;

Gretchen Kreitler; Marcie Shoemaker;

Angela Marshall; Lake Mattamuskeet

National Wildlife Refuge

No Data No Data No Data No Data No Data No Data Adult, Immature N. Carolina NCWRC

(Ruth Boettcher,

personal

communication25)
258

 Handling of Live Hatchlings- Larry

Crowder, Duke Marine Lab

120 0 0 0 0 0 Hatchling N. Carolina NCWRC

(Ruth Boettcher,

personal

communication25)

 Display of Live Hatchlings: NC Division

of Aquariums

15 0 0 0 0 0 Hatchling N. Carolina NCWRC

(Ruth Boettcher,

personal

communication25)

 Display of Live Juveniles - NC Division of

Aquariums

No Data No Data No Data No Data No Data No Data Immature N. Carolina NCWRC

(Ruth Boettcher,

personal

communication25)

S. Carolina - Tagging of Nesting Females 88(0) No Data No Data No Data No Data No Data Adult S. Carolina SCDNR

(Sally Murphy,

personal

communication 26)

 Relocation of Turtle Nests No Data No Data No Data No Data No Data No Data Hatchling S. Carolina SCDNR

(Sally Murphy,

personal

communication 26)

 Probing Nests No Data No Data No Data No Data No Data No Data Hatchling S. Carolina SCDNR

(Sally Murphy,

personal

communication26)

 Releasing Disoriented Hatchlings No Data No Data No Data No Data No Data No Data Hatchling S. Carolina SCDNR

(Sally Murphy,

personal

communication26)

 Holding of Live Turtles For Rehab No Data No Data No Data No Data No Data No Data Adult, Immature S. Carolina SCDNR

(Sally Murphy,

personal

communication26)

 Public Turtle Watches No Data No Data No Data No Data No Data No Data Adult, Hatchling S. Carolina SCDNR

(Sally Murphy,

personal

communication26)
259

Georgia - Tagging of Nesting Females -

Kris Carrol, Caretta Research Project;

Rebecca Bell, Little Cumberland Island Sea

Turtle Project

No Data No Data No Data No Data No Data No Data Adult Georgia GDNR

(Mark Dodd,

personal

communication27)

 Relocation of Turtle Nests - Jennifer

Bjork, Cumberland Island National Seashore;

Carol Ruckdeschel, GADNR volunteer;

Rebecca Bell, Little Cumberland Island Sea

Turtle Project; Jan Caton Jekyll Island Sea

Turtle Project; Donna Stewart, Jekyll Island

4-H Center; Catherine Quinn, St. Simons

Island Sea Turtle Project; Tom Henslee, Sea

Island Company; Eric Kellon, Little St.

Simons Island; Sarah Gaines, GADNR sea

turtle intern - Sapelo Island; Debra Keinath,

USFWS - Blackbeard Island; Dr. Gale

Bishop, St. Catherine Island Sea Turtle

Project; Jordan Lundy & Liberty Moore,

GADNR - sea turtle interns on Ossabaw

Island; Kris Carrol, Caretta Research

Project; Danny Carpenter, Tybee Island

Public Works

No Data No Data No Data No Data No Data No Data Hatchling Georgia GDNR

(Mark Dodd,

personal

communication 27)

 Probing Nests - Jennifer Bjork,

Cumberland Island National Seashore; Carol

Ruckdeschel, GADNR volunteer; Rebecca

Bell, Little Cumberland Island Sea Turtle

Project; Jan Caton Jekyll Island Sea Turtle

Project; Donna Stewart, Jekyll Island 4-H

Center; Catherine Quinn, St. Simons Island

Sea Turtle Project; Tom Henslee, Sea Island

Company; Eric Kellon, Little St. Simons

Island; Sarah Gaines, GADNR sea turtle

intern - Sapelo Island; Debra Keinath,

USFWS - Blackbeard Island; Dr. Gale

Bishop, St. Catherine Island Sea Turtle

Project; Jordan Lundy & Liberty Moore,

GADNR - sea turtle interns on Ossabaw

Island; Kris Carrol, Caretta Research

Project; Danny Carpenter, Tybee Island

Public Works

No Data No Data No Data No Data No Data No Data Hatchling Georgia GDNR

(Mark Dodd,

personal

communication 27)
260

Florida - Tagging of Nesting Females -

Kennard Watson, St. Andrew Bay Resource

Management Assoc.; John McCarthy,

Manasota Key Sea Turtle Project; Dr.

Raymond Carthy, Univ. of Fla.; David

Addison, The Conservancy of SW Florida;

Jerris Foote, Mote Marine Lab;

>80 No Data No Data No Data No Data No Data Adult Florida FFWCC (Beth

Morford, personal

communication 28)

Permit#TP038

Permit#TP062

Permit#TP094

Permit#TP116

Permit#TP126

 Measuring coelomic pressure - Richie

Moretti, Hidden Harbor Marine

Environmental Project

25 0 25 25 0 0 Adult &

immature

Florida FFWCC (Beth

Morford, personal

communication 28)

Permit#TP103

 Developmental ecology of immature

turtles - Wayne Witzell, NMFS

4 0 1 44 1 0 Benthic

immature

Gullivan Bay,

Florida

FFWCC (Beth

Morford, personal

communication28)

Permit#TP030

 Relocation of Turtle Nests - Dr. David

Nelson, USACOE

No Data No Data No Data No Data No Data No Data Hatchling Florida FFWCC (Beth

Morford, personal

communication28)

Permit#TP070

 Temperature Loggers in Nests - Dennis

Kellenberger, Clearwater Marine Aquarium

120 0 0 0 0 0 Hatchling Florida FFWCC (Beth

Morford, personal

communication28)

Permit#TP013

 Satellite Tagging- Dr. Lew Ehrhart, Univ.

Central Florida; Mark Nicholas, Gulf Islands

National Seashore; Jerris Foote, Mote Marine

Laboratory

12 6 6 0 0 0 Adult, Immature Florida FFWCC (Beth

Morford, personal

communication28)

Permit#TP025

Permit#TP032

Permit#TP126

 Magnetic Navigation By Hatchlings - Dr.

Kenneth Lohmann, UNC-Chapel Hill; Dr.

Jeanette Wyneken, Florida Atlantic

University

328 0 0 0 0 0 Hatchling Florida FFWCC (Beth

Morford, personal

communication28)

Permit#TP065

Permit#TP073

 Nutritional/Behavior Studies - Dr. Jeanette

Wyneken, Florida Atlantic University

1205 30 35 0 0 0 Hatchling Florida FFWCC (Beth

Morford, personal

communication28) 

Permit#TP073
261

 Net Capture of Immature Turtles - Dr.

Raymond Carthy, Univ. of Florida

No Data No Data No Data No Data No Data No Data Immature St. Joseph Bay,

Florida

FFWCC (Beth

Morford, personal

comm 

28)

Permit#TP094

 Turtles in Captivity For Rehab - Richie

Moretti, Hidden Harbor Marine

Environmental Project

No Data No Data No Data No Data No Data No Data Adult, Immature Florida FFWCC (Beth

Morford, personal

comm 

28)

Permit#TP103

 Fibropapillomatosis Transmission Study -

Dr. Lawrence Herbst, Institute for Animal

Studies; Dr. Paul Klein, Univ. of Florida

0 0 <10

(lethal)

0 0 0 Immature Florida FFWCC (Beth

Morford, personal

comm 

28)

Permit#TP106

Permit#TP129

 Caging Nests - David Addison, The

Conservancy of SW Florida

No Data No Data No Data No Data No Data No Data Hatchling Florida FFWCC (Beth

Morford, personal

comm 

28)

Permit#TP116

 Collection of blood samples from netted

sea turtles - Jerris Foote, Mote Marine

Laboratory

0 0 0 2 0 0 Adult &

Immature

Casey Key

Beach, FL

FFWCC (Beth

Morford, personal

comm 

28)

Permit#TP126

 Relocating nests - Elaine C. Akers, Ivey,

Harris & Walls, Inc.; Ana Barragan, Violetta

Villanueva-Mayor, Phillipe Mayor, Rafe

Boulon _ Sandy Point Leatherback Project;

Zandy Hillis-Starr, Brendalee Phillips, Joyce

Wakefield, Catherine Clark, Cat Jung, Myrto

Argyropolou, VI National Park Service, St.

Croix; Rafe Boulon, Thomas Kelly, Sheri

Caseau, VI National Park Service, St. John;

Amy Mackay, James Rebholtz, Sera Harold,

Tom Mizak USFWS

No Data No Data No Data No Data No Data No Data Hatchling USVI USFWS, US Virgin

Islands

(Donna Griffin,

personal

communication29)

Tagging Nesting Females - Ana Barragan,

Violetta Villanueva-Mayor, Phillipe Mayor,

Rafe Boulon _ Sandy Point Leatherback

Project; Zandy Hillis-Starr, Brendalee

Phillips, Joyce Wakefield, Catherine Clark,

Cat Jung, Myrto Argyropolou, VI National

Park Service, St. Croix

No Data No Data No Data No Data No Data No Data Adult St. Croix USFWS, US Virgin

Islands

(Donna Griffin,

personal

communication29)
262

Collecting blood samples - Zandy Hillis-Starr,

Brendalee Phillips, Joyce Wakefield,

Catherine Clark, Cat Jung, Myrto

Argyropolou, VI National Park Service, St.

Croix

No Data No Data No Data No Data No Data No Data Adult St. Croix USFWS, US Virgin

Islands

(Donna Griffin,

personal

communication29)

 Caribbean Relocating nests - Hector

Horta (DNER); Lesbia Montero (Sea

Grant-UPR); Milagros Justiniano (DNER);

Jovino Marquez (DNER); Carlos E. Diez

(DNER); Ana Ruiz (grad student); Oscar

Diez (Navy biologist); Robert van Dam

(DNER)

No Data No Data No Data No Data No Data No Data Hatchling USVI DRNA-PR (Carlos

Diez, personal

communication30)

 Tagging nesting females - Hector Horta

(DNER); Lesbia Montero (Sea Grant-UPR)

Milagros Justiniano (DNER); Jovino Marquez

(DNER); Carlos E. Diez (DNER); Robert

van Dam (DNER)

No Data No Data No Data No Data No Data No Data Adult Humacao,

Fajardo,

Majagues

Project, Caja de

Muertos,

Culebra, Puerto

Rico

DRNA-PR (Carlos

Diez, personal

communication30)

 Moving injured sea turtles - Hector Horta

(DNER); Debora Moore (private veterinary);

Antonico Mignucci (Metropolitan University);

Carlos E. Diez (DNER); Robert van Dam

(DNER)

No Data No Data No Data No Data No Data No Data Adult, Immature 2 rehab facilities

in PR

DRNA-PR (Carlos

Diez, personal

communication30)

 Collecting blood samples - Hector Horta

(DNER); Debora Moore (private veterinary);

Carlos E. Diez (DNER); Robert van Dam

(DNER)

No Data No Data No Data No Data No Data No Data Adult Humacao,

Fajardo

DRNA-PR (Carlos

Diez, personal

communication30)

Non-Permitted Activities

Massachusetts Bottom Trawl Gear 31 1(0) No Data No Data No Data No Data No Data Immature Mass state

waters

Wellfleet Bay

Wildlife Sanctuary

(Robert Prescott,

personal

communication32)
263

Massachusetts Lobster Pot Fishery33 No Data [85] / [116] No Data No Data No Data No Data Adult, Immature Mass offshore

waters

Prescott, 1988;

Wellfleet Bay

Wildlife Sanctuary

(Robert Prescott,

personal

communication 32)

Massachusetts Pound Net (Weir) Fishery 34 No Data No Data No Data No Data No Data No Data Benthic

Immature

Nantucket

Sound, MA

Wellfleet Bay

Wildlife Sanctuary

(Robert Prescott,

personal

communication 32)

Massachusetts pound net incidental

captures35

0 1(0) 0 0 0 0 Benthic

Immature

Massachusetts STSSN (Wendy

Teas, personal

communication 36)

Massachusetts gill net incidental captures 35 1(0) 0 0 0 0 0 Immature Massachusetts STSSN (Wendy

Teas, personal

communication 36)

Massachusetts non-shrimp trawl incidental

captures 35

0 0 0 1(0) 0 0 No Data Massachusetts STSSN (Wendy

Teas, personal

communication36)

Massachusetts fish trap incidental captures35 1 (0) 0 0 0 0 0 No Data Massachusetts STSSN (Wendy

Teas, personal

communication36)

Massachusetts Hook-and-line incidental

captures 35

1(0) 0 0 0 0 0 Immature Massachusetts STSSN (Wendy

Teas, personal

communication36)

Massachusetts unknown capture method

incidental captures

1(0) 0 0 0 0 0 Immature Massachusetts STSSN (Wendy

Teas, personal

communication36)

Rhode Island Bottom Trawl Gear occasionall

y

0 0 0 0 0 Adult, Immature Rhode Island

state waters

Anonymous 1995
264

Rhode Island Gillnetting No Data No Data No Data No Data No Data No Data Adult, Immature Rhode Island

inshore and

nearshore

Anonymous 1995

Rhode Island Large Fish Traps No Data No Data No Data No Data No Data No Data Adult, Immature off of Newport,

RI

Anonymous 1995

Rhode Island Fish trap incidental captures35 2(0) 10(0) 0 0 0 0 Immature Rhode Island STSSN (Wendy

Teas, personal

communication36)

Rhode Island Lobster Pots No Data No Data No Data No Data No Data No Data Adult, Immature Rhode Island

inshore and

offshore

Anonymous 1995

Rhode Island pound net incidental captures35 0 2(0) 0 0 0 0 Immature Rhode Island STSSN (Wendy

Teas, personal

communication36)

Rhode Island non-shrimp trawl incidental

captures35

0 1(1) 0 0 0 0 Immature Rhode Island STSSN (Wendy

Teas, personal

communication36)

Connecticut Bottom Trawl Gear No Data No Data No Data No Data No Data No Data Adult, Immature Apr - Oct

Block Island

Sound, CT

Anonymous 1995

Connecticut Gillnetting No Data No Data No Data No Data No Data No Data Adult, Immature Long Island

Sound and adj

marine waters,

CT

Anonymous 1995

Connecticut Lobster Pots No Data No Data No Data No Data No Data No Data Adult, Immature Long Island

Sound and adj

marine waters,

CT

Anonymous 1995

New York Bottom Trawl Gear 37 No Data No Data No Data No Data No Data No Data Adult, Immature offshore in state

and fed waters,

Long Island So,

Block Island So,

PeconicGardiners Bay

Anonymous 1995
265

New York Pound Net Fishery 144(0) 0 43(0) 52(0) 0 0 Immature Long Island

Sound, NY

Morreale and

Standora 1998

New York Gillnet Fishery No Data No Data No Data No Data No Data No Data Adult, Immature New York Anonymous 1995

New York fish trap incidental captures35 2 (0) 0 1 (0) 0 0 0 Immature New York STSSN (Wendy

Teas, personal

communication36)

New York non-shrimp trawl incidental

captures35

2(0) 2(2) 0 0 0 0 Immature-CC

No Data for DC

New York STSSN (Wendy

Teas, personal

communication36)

New York fishing net incidental captures35 1(0) 0 0 0 0 0 Immature New York STSSN (Wendy

Teas, personal

communication36)

New York gill net incidental captures35 1 (0) 0 1 (0) 0 0 0 Immature New York STSSN (Wendy

Teas, personal

communication36)

New York Lobster Fishery Mostly Mostly Fewer Fewer 0 0 Adult, Immature New York Long Island Univ.

(Sam Sadove,

personal

communication 38)

New York set net incidental captures35 0 0 0 1(0) 0 0 Immature New York STSSN (Wendy

Teas, personal

communication36)

New Jersey Bottom Trawl Gear 39 No Data No Data No Data No Data No Data No Data Adult, Immature offshore New

Jersey

Anonymous 1995

New Jersey Gillnet Fishery No Data No Data No Data No Data No Data No Data Adult, Immature NJ State waters

and offshore

Anonymous 1995

New Jersey non-shrimp trawl incidental

captures35

2(0) 0 0 0 0 0 Immature New Jersey STSSN (Wendy

Teas, personal

communication36)
266

New Jersey Hook-and-line incidental

captures35

1(0) 0 0 0 0 0 Immature New Jersey STSSN (Wendy

Teas, personal

communication36)

New Jersey pound net incidental captures35 16(0) 0 0 0 0 0 Immature New Jersey STSSN (Wendy

Teas, personal

communication36)

New Jersey Unknown capture method

incidental captures35

1(1) 0 0 0 0 0 Adult New Jersey STSSN (Wendy

Teas, personal

communication36)

Delaware Horseshoe Crab Fishery - benthic 

 trawls

No Data No Data No Data No Data No Data No Data Adult, Benthic

Immature

Delaware Bay Spotila et al. 1998

Delaware non-shrimp trawl incidental

captures35

9(1) 0 0 3(0) 0 0 Immature Delaware STSSN (Wendy

Teas, personal

communication36)

Delaware Gillnet Fishery 40 No Data No Data No Data No Data No Data No Data Adult, Benthic

Immature

Delaware Bay Anonymous 1995

Delaware Fish Trap Fisheries 41 No Data No Data No Data No Data No Data No Data Adult, Immature EEZ off

Delaware

Anonymous 1995

Hook-and-line Fisheries - Delaware Bay 12 0 0 0 0 0 Benthic

Immature

Delaware Bay Spotila et al. 1998

Delaware Drift net incidental captures35 2(0) 0 0 0 0 0 Immature Delaware STSSN (Wendy

Teas, personal

communication36)

Maryland Bottom Trawl Gear No Data No Data No Data No Data No Data No Data Adult, Pelagic

Immature

state water >

1nm

Anonymous 1995

Maryland Gillnet Fishery No Data No Data No Data No Data No Data No Data Adult,Immature state offshore

waters,

Chesapeake

Bay, MD

Anonymous 1995

Maryland Poundnet Fishery No Data No Data No Data No Data No Data No Data Adult, Benthic

Immature

Chesapeake

Bay, MD

Anonymous 1995
267

Maryland Poundnet Fishery incidental

captures35

0 0 0 3(0) 0 0 Immature Maryland STSSN (Wendy

Teas, personal

communication36)

Maryland Hook-and-line Fisheries No Data No Data No Data No Data No Data No Data Adult, Immature Md. state waters Anonymous 1995

Maryland non-shrimp trawl incidental

captures35

1(0) 0 0 0 0 0 Immature Maryland STSSN (Wendy

Teas, personal

communication36)

Maryland unknown capture method incidental

captures35

2(0) 0 0 0 0 0 No Data Maryland STSSN (Wendy

Teas, personal

communication36)

Va. Pound Net Fishery incidental captures35 82(1) 1(0) 0 6(0) 0 0 Immature Virginia STSSN (Wendy

Teas, personal

communication36)

Va. Hook-and-line incidental captures35 4(1) 0 0 0 0 0 Immature Virginia STSSN (Wendy

Teas, personal

communication36)

Va. fishing net incidental captures35 1(1) 0 0 0 0 0 Immature Virginia STSSN (Wendy

Teas, personal

communication36)

Va. non-shrimp trawl incidental captures35 2(0) 0 0 0 0 0 Immature Virginia STSSN (Wendy

Teas, personal

communication36)

Va. Gill net incidental captures35 1(1) 0 0 0 0 0 Immature Virginia STSSN (Wendy

Teas, personal

communication36)

North Carolina Pound Net Fishery 42 2898 -

156(0)

0 531 -

30(3)

221 -

10(0)

0 0 Adult, Benthic

Immature

Core & Pamlico

Sound, NC

Epperly et al. 2000
268

North Carolina Hook-and-line Fisheries35 

43 70(0) 1 3 22(0) 0 0 Immature, Adult North Carolina NMFS unpublished

data (Joanne BraunMcNeill, personal

communication 44)

STSSN (Wendy

Teas, personal

communication36)

North Carolina fishing net incidental

captures35

2(1) 1(0) 0 1(0) 0 0 Immature North Carolina STSSN (Wendy

Teas, personal

communication36)

North Carolina seine net incidental captures35 2(1) 0 0 0 0 0 Immature North Carolina STSSN (Wendy

Teas, personal

communication36)

North Carolina gill net incidental captures35 34(4) 6 (2) 19(4) 10 (0) 1 (0) 0 Immature North Carolina NMFS unpublished

data (Joanne BraunMcNeill, personal

communication 44)

STSSN (Wendy

Teas, personal

communication36)

North Carolina shrimp trawl incidental

captures35

22(2) 0 2(0) 5(0) 0 0 Adult &

Immature

North Carolina STSSN (Wendy

Teas, personal

communication36)

North Carolina non-shrimp trawl incidental

captures35

53(6) 0 2(0) 31(1) 1(1) 0 Adult &

Immature

North Carolina STSSN (Wendy

Teas, personal

communication36)

North Carolina unknown capture method

incidental captures35

1(0) 0 1 0 0 0 Immature North Carolina STSSN (Wendy

Teas, personal

communication36)

North Carolina Long Haul Seine Fisheries 13(0) 0 0 1(0) 0 0 Immature North Carolina

inshore waters

NMFS unpublished

data (Joanne BraunMcNeill, personal

communication44)

North Carolina Beach Seine Fisheries No Data No Data No Data No Data No Data No Data Adult &

Immature

North Carolina

inshore and

offshore waters

Epperly and Thayer,

unpubl. manuscript

North Carolina Stop Net Fishery No Data No Data No Data No Data No Data No Data Adult &

Immature

North Carolina

offshore waters

Epperly and Thayer,

unpubl. manuscript
269

North Carolina Purse Net Fishery No Data No Data No Data No Data No Data No Data Adult &

Immature

North Carolina

inshore and

offshore waters

Epperly and Thayer,

unpubl. manuscript

North Carolina Fish Traps Fishery No Data No Data No Data No Data No Data No Data Adult &

Immature

North Carolina 

offshore waters

Epperly and Thayer,

unpubl. manuscript

North Carolina Flynet Fishery No Data No Data No Data No Data No Data No Data Adult &

Immature

North Carolina 

offshore waters

Epperly and Thayer,

unpubl. manuscript

North Carolina Channel Net Fisheries 2(0) 1(0) 1(0) 1(0) 0 0 Immature North Carolina

inshore waters

NMFS unpublished

data (Joanne BraunMcNeill, personal

communication44)

North Carolina Eel Pots Fishery No Data No Data No Data No Data No Data No Data Benthic

Immature

North Carolina

inshore waters

Epperly and Thayer,

unpubl. manuscript

North Carolina Shrimp Pots Fishery No Data No Data No Data No Data No Data No Data Benthic

Immature

North Carolina

inshore waters

Epperly and Thayer,

unpubl. manuscript

North Carolina Crab Pot Fisheries 0 1(0) 0 0 0 0 Immature North Carolina

inshore waters

NMFS unpublished

data (Joanne BraunMcNeill, personal

communication44)

North Carolina Pelagic Longline Fisheries 0.0046-

0.0218/10

00 hooks

0.0116-

0.1183/10

00 hooks

0 0 0 0 Adult & Pelagic

Immature

North Carolina

offshore waters

Epperly and Thayer,

unpubl. manuscript

North Carolina Benthic Longline Fisheries No Data No Data No Data No Data No Data No Data Benthic

Immature

North Carolina

inshore waters

Epperly and Thayer,

unpubl. manuscript

South Carolina gill net incidental captures35 4(4) 0 1(1) 0 0 0 Immature South Carolina STSSN (Wendy

Teas, personal

communication36)

South Carolina whelk trawling fishery45 No Data No Data No Data No Data No Data No Data Adult, Immature South Carolina SCDNR

(David Cupka ,

personal

communication 46)

South Carolina Hook-and-line Fisheries35 0 0 0 2 (0) 0 0 Immature South Carolina STSSN (Wendy

Teas, personal

communication36)

South Carolina shrimp trawl incidental

captures35

1(1) 0 0 1(0) 0 0 Immature South Carolina STSSN (Wendy

Teas, personal

communication36)
270

Georgia Shrimp bait fishery -otter trawls 47 No Data No Data No Data No Data No Data No Data Immature Georgia GDNR

(Mark Dodd 27,

personal

communication)

Georgia whelk fishery48 2 0 2 3 0 0 Immature Georgia GDNR

(Mark Dodd 27,

personal

communication)

Georgia blue crab fishery (entanglements) No Data No Data No Data No Data No Data No Data Immature, Adult Georgia GDNR

(Mark Dodd 27,

personal

communication)

Georgia shrimp trawl incidental captures35 3(2) 0 0 2(1) 0 0 Immature Georgia STSSN (Wendy

Teas, personal

communication36)

Georgia non-shrimp trawl incidental

captures35

0 0 0 1(0) 0 0 No Data Georgia STSSN (Wendy

Teas, personal

communication36)

Georgia Hook-and-line No Data No Data No Data No Data No Data No Data Immature Georgia GDNR

(Mark Dodd 27,

personal

communication)

Florida - Hook-and-line35 7(1) 0 30(0) 4(0) 0 0 Immature Florida-Atlantic STSSN (Wendy

Teas, personal

communication36)

Florida - Hook-and-line35 7(1) 0 1(0) 20(0) 0 0 Immature Florida-Gulf STSSN (Wendy

Teas, personal

communication36)

Florida fish trap incidental captures35 1(1) 0 0 0 0 0 Adult Florida-Gulf STSSN (Wendy

Teas, personal

communication36)

Florida try net incidental captures35 1(0) 0 2(0) 0 0 0 Immature Florida-Atlantic STSSN (Wendy

Teas, personal

communication36)

Florida shrimp trawl incidental captures35 4(1) 0 0 0 0 0 Adult &

Immature

Florida-Atlantic STSSN (Wendy

Teas, personal

communication36)
271

Florida shrimp trawl incidental captures35000 7(1)00 Immature Florida-Gulf STSSN (Wendy

Teas, personal

communication36)

Florida non-shrimp trawl incidental captures35 5(0)00000 Adult &

Immature

Florida-Gulf STSSN (Wendy

Teas, personal

communication36)

Florida fishing net incidental captures35 2(0)00000 Immature Florida STSSN (Wendy

Teas, personal

communication36)

Florida gill net incidental captures35 1(1)0 1(1)000 Immature Florida-Atlantic STSSN (Wendy

Teas, personal

communication36)

Florida gill net incidental captures35 1(0)0 2(1) 1(0)00 Immature Florida-Gulf STSSN (Wendy

Teas, personal

communication36)

Florida long line incidental captures35 2(2)00000 Adult &

Immature

Florida-Gulf STSSN (Wendy

Teas, personal

communication36)

Florida cast net incidental captures3500 1(0)000 Immature Florida-Atlantic STSSN (Wendy

Teas, personal

communication36)

Florida set net incidental captures35 1(0)0 12(0)000 Immature Florida-Atlantic STSSN (Wendy

Teas, personal

communication36)

Florida unknown capture method incidental

captures35

00 1(0)0 2(0)0 Immature Florida-Atlantic STSSN (Wendy

Teas, personal

communication36)

Alabama shrimp trawl incidental captures3500 1 (0) 1 (0)00 Adult &

Immature

Alabama STSSN (Wendy

Teas, personal

communication36)

Mississippi Hook-and-line incidental

captures35

000 7(0)00 Immature Mississippi STSSN (Wendy

Teas, personal

communication36)

Mississippi shrimp trawl incidental captures35 3(0)00 13(1) 1(0)0 Immature Mississippi STSSN (Wendy

Teas, personal

communication36)
272

Mississippi non-shrimp trawl incidental

captures35

1(0)00000 Adult Mississippi STSSN (Wendy

Teas, personal

communication36)

Mississippi gill net incidental captures350 1 (0)0000 Immature Mississippi STSSN (Wendy

Teas, personal

communication36)

Mississippi unknown capture method

incidental captures35

000 1(0)00 Immature Mississippi STSSN (Wendy

Teas, personal

communication36)

Louisiana shrimp trawl incidental captures35 2(0)0 1(0) 12(5)00 Immature Louisiana STSSN (Wendy

Teas, personal

communication36)

Louisiana gill net incidental captures35000 2(0)00 Immature Louisiana STSSN (Wendy

Teas, personal

communication36)

Louisiana fishing net incidental captures35000 1(0)00 Immature Louisiana STSSN (Wendy

Teas, personal

communication36)

Louisiana set net incidental captures35000 1(0)00 Immature Louisiana STSSN (Wendy

Teas, personal

communication36)

Louisiana non-shrimp trawl incidental

captures35

1(1)00000 No Data Louisiana STSSN (Wendy

Teas, personal

communication36)

Louisiana Hook-and-line incidental captures35000 1(0)00 Immature Louisiana STSSN (Wendy

Teas, personal

communication36)

Louisiana seine net incidental captures35 2(0)00 1(0)00 Adult &

Immature

Louisiana STSSN (Wendy

Teas, personal

communication36)

Louisiana unknown capture method incidental

captures35

00 1(0)000 No Data Louisiana STSSN (Wendy

Teas, personal

communication36)

Texas Hook-and-line Fisheries 49000 288 (91)00 Benthic

Immature

Texas Canon and Flannagan

1996, Cannon et al.

1994
273

Texas Hook-and-line incidental captures35 3 (0)0 9(1) 99 (0) 4 (0)0 Immature Texas STSSN (Wendy

Teas, personal

communication36)

Texas fishing net incidental captures35000 2(1)00 Immature Texas STSSN (Wendy

Teas, personal

communication36)

Texas gill net incidental captures3500 7(4) 4(3)00 Immature Texas STSSN (Wendy

Teas, personal

communication36)

Texas cast net incidental captures3500 3(0)000 Immature Texas STSSN (Wendy

Teas, personal

communication36)

Texas seine net incidental captures3500 3(0)000 Immature Texas STSSN (Wendy

Teas, personal

communication36)

Texas set net incidental captures350000 1(1)0 Immature Texas STSSN (Wendy

Teas, personal

communication36)

Texas trot line incidental captures3500 1(0)000 Immature Texas STSSN (Wendy

Teas, personal

communication36)

Texas shrimp trawl incidental captures35 5(2)0 2(0) 20(3) 1(0)0 Immature Texas STSSN (Wendy

Teas, personal

communication36)

Texas non-shrimp trawl incidental captures35 2(0)00 1(0)00 Immature Texas STSSN (Wendy

Teas, personal

communication36)

Texas try net incidental captures35000 1(0)00 No Data Texas STSSN (Wendy

Teas, personal

communication36)

Texas unknown capture method incidental

captures35

00 1(0) 2(0)00 Immature Texas STSSN (Wendy

Teas, personal

communication36)

Boat strikes - USVI 50 [0] [0] / [42] [38] / [42] [0] [4] / [42]0 Adult &

Immature

USVI Boulon 2000

Poaching - USVI 51 [0] [4] / [16] [4] / [16] [0] [8] / [16]0 Adult &

Immature

USVI Boulon 2000
274

Entanglement in fishing gear - USVI 52 [0] [1] / [13] [9] / [13] [0] [3] / [13] 0 Adult &

Immature

USVI Boulon 2000

USVI fish trap incidental captures35 0 0 2(1) 0 0 0 Immature USVI STSSN (Wendy

Teas, personal

communication36)

Boat strikes - Puerto Rico No Data No Data No Data No Data No Data No Data Adult &

Immature

Puerto Rico Maria Calixta Ortiz

Rivera 2000

Poaching - Puerto Rico No Data No Data No Data No Data No Data No Data Adult, Immature,

eggs

USVI, Puerto

Rico

Boulon, 2000

Maria Calixta Ortiz

Rivera 2000

Entanglement in fishing gear - Puerto Rico No Data No Data No Data No Data No Data No Data Adult, Immature USVI, Puerto

Rico

Boulon, 2000

Maria Calixta Ortiz

Rivera 2000

Puerto Rico Fishing net incidental captures35 0 0 2(0) 0 0 0 Immature Puerto Rico STSSN (Wendy

Teas, personal

communication36)

Puerto Rico Hook-and-line incidental

captures35

0 0 0 0 2 (0) 0 Immature Puerto Rico STSSN (Wendy

Teas, personal

communication36)

Beach and coastal lighting - Caribbean No Data No Data No Data No Data No Data No Data Adult, Hatchling USVI, Puerto

Rico

DRNA-PR (Carlos

Diez, personal

communication 30);

Virgin Islands

National Park (Rafe

Boulon, personal

communication53)

Marine Debris in the Caribbean54 No Data No Data No Data No Data No Data No Data Adult, Hatchling USVI Rafe Boulon,

2000

Foreign Activities

Canada Longline No Data No Data No Data No Data No Data No Data Pelagic

Immature

NW Atlantic James 2000

Canada Gillnet No Data No Data No Data No Data No Data No Data Pelagic NW Atlantic

(coastal)

Goff & Lien 1988,

Goff et al. 1994,

Anonymous 1996

Uruguay Longline No Data No Data No Data No Data No Data No Data Pelagic

Immature

SW Atlantic Achaval et al. 2000
275

Mexico Longline 55 43 2 0 1 4 0 Pelagic

Immature

Gulf of Mexico Ramirez & Ania

2000

Spain Longline 56 1098 2 0 0 0 0 Pelagic

Immature

Western Med Aguilar et al. 1995

Spain Longline 57 443-8389

1,953-

19,987

0 0 0 0 0 Pelagic

Immature

Western Med Caminas 1997

Spain Gillnet 24(1) 236 2 0 0 0 0 No Data Western Med Silvani et al. 1999

Italy Longline 58 650 0 0 0 0 0 Pelagic

Immature

Central Med Argano et al. 1992

Italy Gillnet 59 397 0 0 0 0 0 Pelagic

Immature

Central Med Argano et al. 1992

Italy Longline 60 275 “few” 0 0 0 0 Pelagic

Immature

Central Med DeMetrio &

Megalfonou 1988

Italy Gillnet 61 16,000 0 0 0 0 0 Pelagic Central Med DeMetrio &

Megalfonou 1988

Italy Longline 62 1817 6 0 0 0 0 Pelagic

Immature

Central Med DeMetrio et al. 1983

Malta Longline 63 1500-

2500

(500-600)

0 0 0 0 0 Pelagic

Immature

Central Med Gramentz 1989

Greece Longline 64 116 0 0 0 0 0 Pelagic

Immature

Eastern Med Panou et al. 1991,

Panou et al. 1992

French Guyana Gill net 65 No Data 0 0 0 0 0 Pelagic

Immature

French Guyana

(coastal)

Chevalier et al. 1999

Portugal Bottom set line 66 500 0 0 0 0 0 Pelagic

Immature

Madeira Dellinger and

Encarnacao 2000

West Africa poaching ‘large

numbers

taken’

0 0 0 0 0 Adult Cape Verde

nesting beaches

Cabrera et al 2000

West Africa nets, hook(gaff) and hand No Data No Data No Data No Data No Data No Data Adult and

Immature

Sao Tome

coastal waters

Graff 1995,

Castroviejo et al,

1994
276

Nicaragua gill net, spear No Data No Data No Data No Data No Data No Data Adult and

Immature

Nicaraguan

coastal waters

Lagueux 1998,

Lagueaux et al.

1998, Lima et al.

1999

Venezuela unknown gear 0 0 “often

captured”

0 0 0 Adult and

Immature

La Blanquilla

Island,

Venezuela

Fallabrino et al. 2000

Venezuela shrimp trawl 67 15 6 16 0 11 0 Adult and

Immature

NE coastal

Venezuela

Marcano and Alio-M

2000

Cuba - unknown gear 68 No Data No Data No Data No Data No Data No Data Adult Coastal Cube Gavilan 2000,

Alvarez 2000

Trinidad/Tobago gillnet 69 [43] [0] [0] [0] [0] [0] Adult Coastal Trnidad

 & Tobago

Newsday 2000,

(Scott Eckert,

personal

communication70);

Eckert and Lien 1999

Ghana 71

No Data No Data No Data No Data No Data No Data Adult Ghana beaches BBC News 2000

Belize nets (trawl & gill net), harpoon, hook,

and spear 72

No Data No Data No Data No Data No Data No Data Adult and

Immature

Coastal Belize Smith et al, 1992

Suriname net (trawl, drift and set) and hand

captures 73

No Data No Data No Data No Data No Data No Data Adult and

Immature

Coastal waters

and beaches of

Suriname

Reichart and Fretey

1993

Antigua/Barbuda longline trammel nets,

seines and gill nets 74

No Data No Data No Data No Data No Data No Data Adult and

Immature

Coastal waters Fuller et al. 1992

St. Lucia net and hand captures 75 No Data No Data No Data No Data No Data No Data Adult Coastal waters

and beaches

d’Auvergne and

Eckert 1993

St. Kitts and Nevis turtle nets, gill nets,

beach seines and hand captures 76

No Data No Data No Data No Data No Data No Data Adult and

immature

Coastal waters

and beaches

Eckert and

Honebrink 1992

St. Vincent and the Grenadines turtle nets,

spear gun and hand (longline) captures 77

No Data No Data No Data No Data No Data No Data Adult and

immature

Coastal waters

and beaches

Scott and Horrocks

1993

Netherland Antilles net (purse seine), longline

and spear gun captures 78

No Data No Data No Data No Data No Data No Data Adult and

immature

Coastal waters Sybesma 1992

Aruba seine and longline captures 79 No Data No Data No Data No Data No Data No Data Immature Coastal waters Barmes et al. 1993
277

Barbados net, spear and hand captures 80 No Data No Data No Data No Data 1440; 400 No Data Adult and

immature

Coastal waters

and beaches

Horrocks 1992

British Virgin Islands net and hand (longline)

captures,81

No Data No Data No Data No Data No Data No Data Adult and

immature

Coastal waters Eckert et al. 1992,

Cambers and Lima

1990, Tobias 1991

Achaval, F., Y. H. Marin, and L.C. Barea. 2000. Incidental capture of turtles with pelagic longline. NMFS-SCFSC-Tech Memo. 436:261.

Aguilar, R., J. Mas, X. Pastor. 1995. Impact of Spanish swordfish longline fisheries on the loggerhead sea turtle Caretta caretta population in the

Western Mediterranean. NOAA Tech. Memo. NMFS-SEFSC-361: 1-6.

Alvarez, B.L.A. 2000. Hawksbill turtle feeding habits in Cuban waters. 2000. NOAA Tech. Memo. NMFS-SEFSC-436:65.

Anonymous. 1995. State and federal fishery interactions with sea turtles in the mid-Atlantic area. In Proceedings of the Workshop of the Management

and Science Committee of the Atlantic States Marine Fisheries Commission July 17-18, Richmond, Virginia

Anonymous. 1996. North Atlantic Leatherback turtle workshop. November 22, 1996. Life Sciences Center, Dalhousie University, Halifax, Nova Scotia.

 266 pp.

Argano, R., R. Basso, M. Cocco, and G. Gerosa. 1992. Nouvi data sugli spostamenti di tartaruga marina comune (Caretta caretta) in Mediterraneo.

Bollettino Musel Istitiuti Universita Genova 56-57:137-163.

d’Auvergne, C. and K.L. Eckert. 1993. WIDECAST sea turtle recovery action plan for St. Lucia. Sea turtle recovery action plan for St. Lucia.

Caribbean Environment Program Technical Report 26:70 pp. United Nations Environmental Programme, Kingston, Jamaica.

Barmes, T., K.L. Eckert, and J. Sybesma. 1993. Wider Caribbean Sea Turtle Recovery Team and Conservation Network (WIDECAST). Sea turtle

recovery action plan for Aruba. Caribbean Environment Program Technical Report 25: 58 pp. United Nations Environmental Programme,

Kingston, Jamaica.

BBC News. 2000. Saving the giant sea turtle. Africa Section: Thursday, 20, July, 2000

Boulon, R.H. 2000. Trends in sea turtle strandings, U.S. Virgin Islands: 1982 to 1997. NOAA Tech. Memo. NMFS-SEFSC-436:261-263.

Cabrera, I, D. Cejudo, and L.F.Lopez-Jurado. 2000 Human predation on marine turtles in the Archipelago of Cape Verdes, Western Africa. NOAA

Tech. Memo. NMFS-SEFSC-443:217.
278

Cambers, G. and H. Lima. 1990. Leatherback turtles disappearing from the BVI. Marine Turtle Newsletter 49:4-7.

Caminas, J.A. 1997. Capturas accidentales de tortuga boba (Caretta caretta, L. 1758) en el Mediterránio occidental en la pesquería de palangre de

superficie de pez espada (Xiphias gladius L.) International Commission for the Conservation of Atlantic Tunas Collective Volume of Scientific

Papers 46:446-455.

Cannon, A.C. and J.P. Flanagan. 1996. Trauma and treatment of Kemp’s ridley sea turtles caught on hook-and-line by recreational fishermen. Draft

abstract submitted for the 18th Annual Sea Turtle Symposium. Hilton Head, S.C. February 1996.

Cannon, A.C. , C.T. Fontaine, T.D. Williams, D.B. Revera, C.W. Caillouet, Jr. 1994. Incidental catch of Kemp’s ridley sea turtles (Lepidochelys

kempi), by hook and line, along the Texas Coast, 1980-1992. U.S. Dept. Commer. NOAA Tech. Memo NMFS-SEFSC-341: 40-42.

Castroviejo, J., J.B. Juste, J.P. Del Val, R. Castelo, and R. Gil. 1994. Diversity and status of sea turtle species in the Gulf of Guinea islands.

Biodiversity and Conservation 3: 828-836.

Chevalier, J., X. Desbois, and M. Girondot. 1999. The reason of decline of leatherback turtles (Dermochelys coriacea) in French Guiana: a

hypothesis. In: C. Miaud and R. Guyetant (eds), Current studies in herpetology. 480 pp. ISBN: 29514994-0X.

Dellinger, T. and H. Encarnacao. 2000. Accidental capture of sea turtles by the fishing fleet based at Madeira Island, Portugal. NOAA Tech. Memo.

NMFS-SEFSC-443:218.

De Metrio, G. and P. Megalofonou. 1988. Mortality of marine turtles (Caretta caretta L. and Dermochelys coriacea L.) consequent to accidental

capture in the Gulf of Taranto. Rapports et Proces-Verbaux des Reunions Conseil International pour l’Exploration de la Mer Mediterranee 31(2):

285.

De Metrio, G., G. Petrosino, A. Matarrese, A. Tursi, and C. Montanaro. 1983. Importance of the fishery activities with drift lines on the populations of

caretta caretta (L.) and Dermochelys coriacea (L.) (Reptilia, Testudines), in the Gulf of Taranto. Oebalia IX, N.S. 43-53.

Eckert, K.L and T.D. Honebrink. 1992. WIDECAST sea turtle recovery and action plan for St. Kitts and Nevis. CEP Tech. Rep. 17:116 pp. UNEP

Caribbean Environment program, Kingston, Jamaica. 

Eckert, S.A. and J. Lien. 1999. Recommendations for eliminating incidental capture and mortality of leatherback turtles, Dermochelys coriacea, by

commercial fisheries in Trinidad and Tobago. A report to the Wider Caribbean Sea Turtle Conservation network (WIDECAST). Hubbs-Sea

World research Institute Tech. Rep. No. 2000-310. 7 pp.

Eckert, K.L., J.A. Overing, B.B. Lettsome. 1992. WIDECAST sea turtle recovery action plan for the British Virgin Islands. CEP Tech. Rep. 15: 116 pp.

UNEP Caribbean Environment Programme, Kingston, Jamaica.
279

Epperly, S.P., J. Braun-McNeill, and A. Bass. 2000. In-water population index surveys: North Carolina, U.S.A. Proceedings of the Eighteenth Annual

Sea Turtle Symposium, 3-7 March, 1998, Mazatlan, Mexico. U.S. Dep. Commer., NOAA Tech Memo. NMFS-SEFSC-436:62.

Epperly, S.P. and V. G. Thayer. Unpublished manuscript. Marine mammal and sea turtle/fisheries interactions in North Carolina. 10 pp.

Fallabrino, A., A. Rodriquez, A. Trujillo, and J. Marcano. 2000. Green turtle (Chelonia mydas) capture by Artesanal fishermen in la Blanquilla Island,

Venezuela. NOAA Tech. Memo. NMFS-SEFSC-436:264.

Fish and Wildlife Service. 2000a. Permit#TE840727-0 issued to Ms. Donna Shaver-Miller, Padre Island National Seashore, Corpus Christi, TX 78480

by the FWS Albuquerque, NM office, April 30. Expires 4/30/2002.

Fish and Wildlife Service. 2000b. Endangered Species Act Section 7 Consultation Biological Opinion for a proposed Preconstruction Modifications of

Authorized Improvements for the Wilmington Harbor Project, New Hanover and Brunswick Counties, North Carolina. May 3. 61 pp.

Fish Wildlife Service. 2000c. Amendment to Endangered Species Act Biological Opinion for COE Coast of Florida Study (Log # 4-1-96-F-268), Region

III beach nourishment and renourishment projects in Palm Beach, Broward and Dade Counties, Florida. Service Log # 4-1-00-I-233. February 8.

 2 pp.

Fish Wildlife Service. 2000d. Amendment to Endangered Species Act Biological Opinion for COE Coast of Florida Study (Log # 4-1-96-F-268), Region

III beach nourishment and renourishment projects in Palm Beach, Broward and Dade Counties, Florida. Service Log # 4-1-00-F-701. October 4.

 4 pp.

Fish Wildlife Service. 2000e. Amendment to Endangered Species Act Biological Opinion for COE Coast of Florida Study (Log # 4-1-96-F-268), Region

III beach nourishment and renourishment projects in Palm Beach, Broward and Dade Counties, Florida. Service Log # 4-1-00-F-497. October 31.

 5 pp.

Fish and Wildlife Service. 2000f. Endangered Species Act Section 7 Consultation Biological Opinion for a proposed Lido Beach Shore Protection Project

located on Lido Key, Sarasota County, Florida. August 13. Log # 4-1-99-F-252. 21 pp.

Fish and Wildlife Service. 2000g. Endangered Species Act Section 7 Consultation Biological Opinion for a proposed Lighthouse Point groin construction

located in Longboat Key, Sarasota County, Florida. January 18. Log # 4-1-99-F-99. 22 pp.

Fish and Wildlife Service. 2000h. Endangered Species Act Section 7 Consultation Biological Opinion for a proposed MMS outer continental shelf oil and

gas leasing, exploration, development, production, and abandonment for the Destin Dome 56 Unit Plan in the Eastern Gulf of Mexico. August 7.

 Log# 4-P-00-003. 13 pp.

Fish and Wildlife Service. 2000i. Endangered Species Act Section 7 Consultation Biological Opinion regarding an incidental take permit for The Villages

at Seagrove and Camp Creek, St. Joe Company, Walton County, Florida. June 8. 106 pp. 
280

Fish and Wildlife Service. 2000j. Endangered Species Act Section 7 Initiation of consultation regarding the construction of a dune/berm system in Okaloosa

County and the City of Destin in Okaloosa County, Florida. April 6. Log # 4-P-00-102. 5 pp. 

Fish and Wildlife Service. 2000k. Endangered Species Act Section 7 Initiation of consultation regarding the construction of a dune/berm system 0n the St.

Joseph peninsula, otherwise known as Cape San Blas, Gulf County, Florida. April 6. Log # 4-P-00-103. 5 pp. 

Fish and Wildlife Service. 2000l. Endangered Species Act Section 7 informal consultation regarding the correction of drainage problems at the Miramar

Public Beach access, Walton County, Florida. June 9. Log# 4-P-00-144 4 pp. 

Fish and Wildlife Service. 2000m. Permit#TE025759-0 issued to Ms. Kathryn Craven, Texas A&M University, College Station, TX 77845 by the FWS

Ecological Services, Atlanta, GA office. September 21. Expires 9/30/2002.

Fish and Wildlife Service. 2000n. Endangered Species Act Section 7 Consultation Biological Opinion for a proposed COE implementation of a long-term

beach management strategy which is predicated upon comprehensive beach restoration of the beaches in the City of Gulf Shores, Alabama. June

7. No Log# . 20 pp.

Fish and Wildlife Service. 2000o. Endangered Species Act Section 7 Consultation Biological Opinion regarding the construction of an emergency protective

berm in the area of Dauphin Island, Mobile County, Georgia. March 22. 21 pp. 

Fish and Wildlife Service. 2000p. Endangered Species Act Section 7 Consultation Biological Opinion regarding the proposed inert naval exercises and

training at Vieques Inner Range in Vieques Island, Puerto Rico. July 27. 37 pp. 

Fish and Wildlife Service. 2000q. FWS Endangered Species Incidental Take Permit#TE026114-0 issued to Mr. William Mailloux, Managing Partner

Culebra Northshore, S.E., Culebra regarding the proposed residential development on approx. 64.8 acres at lot 4, Culebra Northshore, Barrio Isidoro,

Culebra, Puerto Ricorto Rico. Expires 10/31/2012.

Fish and Wildlife Service. 1999a. Permit#TE776123-0 issued to Dr. Andre Landry, Texas A&M University-Galveston, Galveston, TX 77554 by the FWS

Ecological Services, Albuquerque, NM office, April 16. Expires 4/30/2001.

Fish and Wildlife Service. 1999b. Permit#TE30177-0 issued to Mr. Anthony F. Amos, Marine Science Institute, University of Texas at Austin, Port Aransas,

TX 78373 by the FWS Albuquerque, NM office, September 10. Expires 9/30/2001.

Fish Wildlife Service. 1999c. Endangered Species Act Informal Consultation No. 2-11-99-I-161 for a proposed Western Geophysical application for a

geophysical permit to do seismic survey work on coastal public land in the Laguna Madre, Baffin Bay, and the Gulf of Mexico in Kleberg and Kenedy

Counties, Texas. August 12. 5 pp.
281

Fish and Wildlife Service. 1999d. Subpermit of FWS Permit#697823-0 issued to Ms. Dana Hartley, NMFS, Northeast Region, One Blackburn Drive,

Gloucester, MA 01930 by the FWS Region 5 Regional Office July 16. Expires 5/06/2003.

Fish Wildlife Service. 1999e. Endangered Species Act Informal Consultation for a proposed North Carolina Division of Water Resources to conduct

dredging operations and spoil disposal in the waters of Roanoke Sound and Shallowbag Bay, NC. December 23. 14 pp.

Fish and Wildlife Service. 1999f. Endangered Species Act Section 7 Consultation Biological Opinion for a proposed Fisher Island maintenance dredging

project in the Visitor Marina on Fisher Island, Miami-Dade County, Florida. October 13. Log # 4-1-98-F-643. 22 pp.

Fish and Wildlife Service. 1999g. Endangered Species Act Section 7 Consultation Biological Opinion for a proposed Lee County Shore Protection Project

in Lee County, Florida. September 29. Log # 4-1-99-F-812. 22 pp.

Fish and Wildlife Service. 1999h. Endangered Species Act Section 7 Consultation Biological Opinion for the proposed testing of Theater Missile Defense

systems n the Eglin Gulf Test Range. August 5. (No FWS Log #). 43 pp.

Fish and Wildlife Service. 1999i. FWS Incidental Take Permit#TE811813-4 issued to County of Volusia, Florida related to vehicular use on public beaches

FWS Region 4 Regional Office October 29. Expires 12/31/2001.

Fish and Wildlife Service. 1999j. FWS Endangered and Threatened Species Permit#TE676379-2 issued to Dr. Andrew Kemmerer, NMFS, SERO, St.

Petersburg, FL by Regional Director, FWS, SE Region. May 4. Expires 05/31/2004.

Fish Wildlife Service. 1998a. Endangered Species Act Biological Opinion for OCS oil and gas lease sales 171, 174, 177, and 180, Gulf of Mexico Western

Planning Area. March 9. 15 pp.

Fish Wildlife Service. 1998b. Endangered Species Act Informal Consultation No. 2-11-98-I-329 for a proposed 3-D Seismic Operation on Padre Island,

in Nueces and Kleberg Counties. August 19. 2 pp.

Fish Wildlife Service. 1998c. Endangered Species Act Informal Consultation No. 2-11-98-I-330 for a proposed Western Geophysical application for a

geophysical permit to do seismic survey work on coastal public land in Redfish, Aransas, and Corpus Christi Bays, Nueces, Aransas, and San

Patricio Counties, Texas. August 21. 5 pp.

Fish Wildlife Service. 1998d. Endangered Species Act Informal Consultation No. 2-11-98-I-365 for a proposed Western Geophysical application for a

geophysical permit to do seismic survey work on coastal public land in the Laguna Madre and Corpus Christi Bay, Nueces and Kleberg Counties,

Texas. October 5. 5 pp.

Fish Wildlife Service. 1998e. Endangered Species Act Biological Opinion for US Armed Forces mission-related vehicle access and driving along Gulf

of Mexico beaches except Shell Island, Tyndall Air Force Base in Bay County, Florida. June 24. Log# 4-P-98-020 30 pp.
282

Fish Wildlife Service. 1998f. Endangered Species Act Biological Opinion for COE management and excavation of the Lake Powell outlet to the Gulf of

Mexico at Camp Helen in Bay County, Florida. July 31. Log# 4-P-97-089 34 pp.

Fish and Wildlife Service. 1998g. Endangered Species Act Section 7 Consultation Biological Opinion for Panama City Beach Nourishment Project located

in Bay County, Florida. April 8. Log# 4-P-97-108. 21 pp.

Fish Wildlife Service. 1997. Endangered Species Act Biological Opinion for MMS outer continental shelf oil and gas leasing, exploration, development,

production, and abandonment for multi-lease sales 169, 172, 175, 178, and 12 in the Central Gulf of Mexico. December 24. Log # 4-P-97-075. 37

pp.

Fish Wildlife Service. 1996a. Endangered Species Act Informal Consultation for the proposed Sandbridge Beach and Virginia Beach, Va., Hurricane

Protection and Beach Erosion Control Projects. July 8. 5 pp.

Fish Wildlife Service. 1996b. Endangered Species Act Biological Opinion for COE Coast of Florida Study, Region III beach nourishment and renourishment

projects in Palm Beach, Broward and Dade Counties, Florida.. Log # 4-1-96-F-268. October 24. 25 pp.

Fish and Wildlife Service. 1996c. Endangered Species Act Section 7 Consultation Biological Opinion regarding an incidental take permit for Brett Real

Estate, Robinson Development Co., Inc. Orange Beach, Alabama. April 8. 29 pp. 

Fish Wildlife Service. 1995a. Endangered Species Act Informal Consultation for the proposed Dam Neck Sand Dune and Beach Nourishment Project,

Virginia Beach, Virginia. November 8. 2pp.

Fish Wildlife Service. 1995b. Endangered Species Act Biological Opinion for COE proposed beach nourishment project in Glynn County, Georgia. Log

# 4-4-95-071. April 20. 23 pp.

Fish Wildlife Service. 1992. Endangered Species Act Biological Opinion for COE proposed revetment on beach in Glynn County, Georgia. Log # 4-4-93-

032. November 5. 3 pp.

Fuller, J.E. K.L. Eckert, and J.I. Richardson. 1992. WIDECAST sea turtle recovery action plan for Antigua and Barbuda. CEP Tech. Rep. 16: 88 pp. UNEP

Caribbean Environmental Program, Kingston, Jamaica

Gavilan, F.M. 2000. Impact of regulatory measures on Cuban marine turtle fisheries. NOAA Tech. Memo. NMFS-SEFSC-436:108-109.

Goff, G.P. and J. Lien. 1988. Atlantic leatherback turtles, Dermochelys coriacea, in cold water off Newfoundland and Labrador. Canadian Field Naturalist

102:1-5.

Goff, G.P., J. Lien, G.B. Stenson, and J. Fretey. 1994. The migration of a tagged leatherback turtle, Dermochelys coriacea, from French Guiana, South

America, to Newfoundland, Canada, in 128 days. Canadian Field Naturalist. 108:72-73.
283

Graff, D. 1995. Nesting and hunting survey of the marine turtles of the island of Sao Tome. 1995. ECOFAC Report, 33 pp.

Gramantz, D. 1989. Marine turtles in the central Mediterranean Sea. Centro. 1(4):41-56.

Horrocks, J. 1992. WIDECAST sea turtle recovery action plan for Barbados. CEP Tech. Rep. 12: 61 pp. UNEP Caribbean Environmental Programme,

Kingston, Jamaica.

James, M.C. 2000. Distribution of the leatherback turtle (Dermochelys coriacea) in Atlantic Canada: Evidence from an observer program, aerial surveys

and a volunteer network of fish harvesters. Master of Science Thesis. Acadia University.

Lagueux, C.J. 1998. Marine turtle fishery of Caribbean Nicaragua: human use patterns and harvest trends. Ph.D. Dissertation, University of Florida,

Gainesville, Florida. 215 pp.

Lagueux, C.J., C. Campbell, and L.H. Herbst. 1998. Demography of marine turtles harvested by Miskito Indians of Atlantic Nicaragua. NOAA Tech. Memo.

NMFS-SEFSC-412:90.

Lima, E., C. Lagueux, D. Castro, and M. Marcovaldi. 1999. From one feeding ground to another: Green turtle migration between Brazil and Nicaragua.

Marine Turtle Newsletter 85:10.

Marcano, L.A. and J.J. Alio-M. 2000. Incidental capture of sea turtles by the industrial shrimping fleet off northwestern Venezuela. NOAA Tech. Memo.

NMFS-SEFSC-436:107.

Morreale, S.J. and E.A. Standora. 1998. Early life stage ecology of sea turtles in northeastern U.S. Waters. U.S. Dep. Commer. NOAA Tech. Memo.

NMFS-SEFSC-413, 49 pp.

National Marine Fisheries Service. 2000a. Endangered Species Act section 10 Permit # 1231 issued to Dr. Llewellyn M. Ehrhart. May 31. 

National Marine Fisheries Service. 2000b. Endangered Species Act section 10 Permit # 1236 issued to Virginia Institute of Marine Science. October 10.

National Marine Fisheries Service. 2000c. Endangered Species Act section 10 Permit # 1245 issued to J. David Whitaker, South Carolina Department

of Natural Resources. May 19.

National Marine Fisheries Service. 2000d. Endangered Species Act section 10 Permit # 1253 issued to Carlos Diez, Puerto Rico Department of Natural

Resources. September 22.

National Marine Fisheries Service. 2000e. Endangered Species Act section 10 Permit # 1259 issued to State of North Carolina, Department of

Environmental and Natural Resources, Division of Marine Fisheries. October 5.
284

National Marine Fisheries Service. 2000f. Endangered Species Act section 7 consultation on the Preconstruction Modifications of Authorized Improvements

(Involving Blasting and Dredging) in Wilmington Harbor, North Carolina. Biological Opinion, August 3. 64 pp.

National Marine Fisheries Service. 2000g. Endangered Species Act section 7 consultation biological opinion: Assateague State Park beach nourishment

project. Office of Protected Resources, National Marine Fisheries Service, Silver Spring, Maryland 20910. Signed December 20, 2000.

[Consultation No. NER/2000/01028]

National Marine Fisheries Service. 2000h. Endangered Species Act section 7 consultation biological opinion: Development and production plan, and rightof-way pipeline application for the Destin Dome 56 Unit. Office of Protected Resources, National Marine Fisheries Service, Silver Spring, Maryland

20910. Signed April 13, 2000. [Consultation No. SER/1999/01398]

National Marine Fisheries Service. 2000i. Endangered Species Act biological opinion regarding the reinitiation of consultation on the Atlantic Pelagic

Fisheries for swordfish, tuna, shark and billfish in the U.S. EEZ: Proposed rule to implement a regulatory amendment to the HMS FMP; reduction

of bycatch and incidental catch in the Atlantic pelagic longline fishery. Office of Protected Resources, National Marine Fisheries Service, Silver

Spring, Maryland 20910. Signed June 30, 2000. [Consultation No. SER/2000/00540]

National Marine Fisheries Service. 2000j. Biological Opinion on the reinitiation of operation of the cooling water intake system at the Brunswick Steam

Electric Plant, Carolina Power and Light Co. Office of Protected Resources, National Marine Fisheries Service, Silver Spring, Maryland 20910.

Signed January 20, 2000. [Consultation No. SER/2000/00411]

National Marine Fisheries Service. 1999a. Endangered Species Act section 7 consultation on the Fishery Management Plan for Atlantic Mackerel, Squid,

and Atlantic Butterfish Fishery and Amendment 8 to the Fishery Management Plan. Biological Opinion. April 28. 48 pp.

National Marine Fisheries Service. 1999b. Endangered Species Act section 7 consultation on the Fishery Management Plan for the Atlantic Bluefish Fishery

and Amendment 1 to the Fishery Management Plan. Biological Opinion, July 2. 54 pp.

National Marine Fisheries Service. 1999c. Endangered Species Act section 7 consultation on the Fishery Management Plan for the Federal Spiny Dogfish

Fishery. Biological Opinion, August 13. 59 pp.

National Marine Fisheries Service. 1999d. Endangered Species Act section 7 consultation on the Fishery Management Plan for the Federal Atlantic Herring

Fishery. Biological Opinion. September 17. 62 pp.

National Marine Fisheries Service. 1999e. Endangered Species Act section 10 Permit # 1187 issued to Stephen M.H. Connett, St. George’s School. April

4.

National Marine Fisheries Service. 1999f. Endangered Species Act section 10 Permit # 1198 issued to Florida Fish and Wildlife Conservation Commission.

 May 13.
285

National Marine Fisheries Service. 1999g. Endangered Species Act section 10 Permit # 1201 issued to Dr. Thane Wibbels. June 11.

National Marine Fisheries Service. 1999h. Endangered Species Act section 10 Permit # 1214 issued to Dr. Jane Provancha. May 25. 

National Marine Fisheries Service. 1999i. Endangered Species Act section 7 consultation biological opinion: Proposed rule to implement the Fishery

Management Plan for Sargassum Habitat of the South Atlantic Region. Office of Protected Resources, National Marine Fisheries Service, Silver

Spring, Maryland 20910. Signed June 21, 1999. [Consultation No. SER/1999/00005]

National Marine Fisheries Service. 1999j. Endangered Species Act section 7 consultation biological opinion: Cooling water intake system at the Crystal

River Energy Complex. Office of Protected Resources, National Marine Fisheries Service, Silver Spring, Maryland 20910. Signed June 16, 1999.

[Consultation No. SER/1998/00067]

National Marine Fisheries Service. 1998a. Endangered Species Act section 7 consultation on shrimp trawling in the southeastern U.S. under the sea turtle

conservation regulations. Biological Opinion, March 24. 32 pp.

National Marine Fisheries Service. 1998b. Endangered Species Act section 7 consultation on United States Coast Guard vessel and aircraft activities along

the Atlantic coast. Biological Opinion, June 8, 1998. 45 pp.

National Marine Fisheries Service. 1998c. Endangered Species Act section 7 consultation on Federal American Lobster Fishery Management Plan under

the Magnuson-Stevens Fishery Conservation and Management Act with a new plan under the Atlantic Coastal fisheries Cooperative Management

Act. Biological Opinion, December 17. 45 pp.

National Marine Fisheries Service. 1998d. Endangered Species Act section 7 consultation regarding the Federal Monkfish Fishery. Biological Opinion,

December 21. 48 pp.

National Marine Fisheries Service. 1998e. Endangered Species Act section 7 revised Incidental Take Statement for the Salem and Hope Creek Nuclear

Generating Stations in the Lower Alloways Creek Township, Salem County, New Jersey. December 29. 10 pp.

National Marine Fisheries Service. 1998f. Endangered Species Act section 10 Permit # 1106 issued to Dr. David Owens, University of Charleston,

Charleston, SC. January 15.

National Marine Fisheries Service. 1998g. Endangered Species Act section 10 Permit # 1133 issued to Dr. Andre Landry, Texas A&M University at

Galveston, TX. May 1.

National Marine Fisheries Service. 1998h. Endangered Species Act section 10 Permit # 1144 issued to Michael J. Bressette and Bruce Peery. Quantum

Resources, Inc. June 23.
286

National Marine Fisheries Service. 1998i. Endangered Species Act section 7 consultation biological opinion: Assateague Island short-term restoration

project, Assateague Island long-term sand management project, Atlantic coast of Maryland Shoreline Protection Project, and Maryland coastal bay

habitat restoration projects. Signed April 6, 1998. [Consultation No. NER/1998/00267]

National Marine Fisheries Service. 1998j. Endangered Species Act section 7 consultation biological opinion: Assateague Island Public Law 84-99

Emergency Response Action. Signed August 4, 1998. [Consultation No. NER/1998/00266]

National Marine Fisheries Service. 1998k. Endangered Species Act section 7 consultation biological opinion: Deepening of Galveston Bay Entrance

Channel (Houston-Galveston Navigation Channels Project) using a hopper dredge. Office of Protected Resources, National Marine Fisheries Service,

Silver Spring, Maryland 20910. Signed December 7, 1998. [Consultation No. SER/1998/00010]

National Marine Fisheries Service. 1998l. Endangered Species Act section 7 consultation biological opinion: Gulf of Mexico Outer Continental Shelf Oil

and Gas Lease Sales: Central Planning Area Lease Sales 169, 172, 175, 178 and 182; Western Area Lease Sales 171, 174, 177 and 180. Office

of Protected Resources, National Marine Fisheries Service, Silver Spring, Maryland 20910. Signed January 6, 1998. [Consultation No.

SER/1998/00068].

National Marine Fisheries Service. 1997a. Endangered Species Act section 7 consultation on continued operation of the circulating water system of the

St. Lucie nuclear generating plant. Biological Opinion. February 7. 39 pp.

National Marine Fisheries Service. 1997b. Endangered Species Act section 7 consultation on Navy Activities off the Southeastern United States along the

Atlantic Coast, May 15. 73 pp.

National Marine Fisheries Service. 1997c. Endangered Species Act section 10 Permit # 1030 issued to Gray’s Reef National Marine Sanctuary March

12.

National Marine Fisheries Service. 1997d. Endangered Species Act section 10 Permit # 1033 issued to U.S. Army Corps of Engineers, Waterways

Experiment Station. March 23.

National Marine Fisheries Service. 1997e. Endangered Species Act section 10 Permit # 1053 issued to Molly Lutcavage, New England Aquarium. July

14.

National Marine Fisheries Service. 1997f. Endangered Species Act section 7 consultation biological opinion: The continued hopper dredging of channels

and borrow areas in the southeastern United States. Signed September 25, 1997. [Consultation No. SER/1997/00070]

National Marine Fisheries Service. 1997g. Endangered Species Act section 7 consultation biological opinion: COE permits to Apache Corporation for

explosive rig removals off Kleberg County Texas and to Chevron U.S.A. Inc. for explosive rig removals off Plaquemine and Lafourche Parish,

Louisiana. Office of Protected Resources, National Marine Fisheries Service, Silver Spring, Maryland 20910. Signed June 10, 1997. [Consultation

No. SER/1997/00037]
287

National Marine Fisheries Service. 1997h. Endangered Species Act section 7 consultation biological opinion: Regulations for Atlantic Coast Weakfish

Fishery in the Exclusive Economic Zone (EEZ). Office of Protected Resources, National Marine Fisheries Service, Silver Spring, Maryland 20910.

Signed June 27, 1997. [Consultation No. FPR/1997/0043]

National Marine Fisheries Service. 1996a. Endangered Species Act section 7 reinitiation of consultation on the Summer Founder Fishery to Include the

Scup and Black Sea Bass Fisheries. Biological Opinion, February 24. 42 pp.

National Marine Fisheries Service. 1996b. Endangered Species Act section 7 consultation on United States Coast Guard vessel and aircraft activities along

the Atlantic coast. Biological Opinion, July 22. 32 pp.

National Marine Fisheries Service. 1996c. Endangered Species Act section 7 consultation on the proposed shock testing of the SEAWOLF submarine off

the Atlantic Coast of Florida during the summer of 1997. Biological Opinion, December 12. 50 pp.

National Marine Fisheries Service. 1996d. Endangered Species Act reinitiation of section 7 consultation regarding current and proposed management

activities conducted under the Northeast Multispecies Fishery Management Plan. Biological Opinion, December 13. 25 pp.

National Marine Fisheries Service. 1996e. Endangered Species Act section 10 Permit # 1008 issued to the State of North Carolina Division of Marine

Fisheries. June 15.

National Marine Fisheries Service. 1996f. Endangered Species Act section 7 consultation biological opinion: Dredging by hopper dredge and beach

replenishment along the U.S. Navy Fleet Combat Training Center at Dam Neck, Virginia Beach, Virginia. Office of Protected Resources, National

Marine Fisheries Service, Silver Spring, Maryland 20910. Signed January 25, 1996. [Consultation No. NER/ 960002]

National Marine Fisheries Service. 1996g. Endangered Species Act section 7 consultation biological opinion: Dredging of the Tampa Harbor Navigation

Channel, Tampa Bay, Florida. Office of Protected Resources, National Marine Fisheries Service, Silver Spring, Maryland 20910. Signed April

9, 1996. [Consultation No. SER/960016]

National Marine Fisheries Service. 1995a. Endangered Species Act section 7 consultation on United States Coast Guard vessel and aircraft activities along

the Atlantic coast. Biological Opinion, September 15. 56 pp.

National Marine Fisheries Service. 1995b. Endangered Species Act section 7 consultation on Nuclear Regulatory Commission operation of the Oyster Creek

Nuclear Generating Station in the Forked River and Oyster Creek, Barnegat Bay, New Jersey. Biological Opinion, September 21. 24 pp.

National Marine Fisheries Service. 1993a. Endangered Species Act section 7 reinitiation of a consultation on the Nuclear Regulatory Commission continued

operation of the Salem and Hope Creek Nuclear Generating Stations in the Lower Alloways Creek Township, Salem County, New Jersey. Biological

Opinion, May 14. 20 pp.
288

National Marine Fisheries Service. 1993b. Endangered Species Act section 7 consultation on Nuclear Regulatory Commission operation of the Oyster Creek

Nuclear Generating Station in the Forked River and Oyster Creek, Barnegat Bay, New Jersey. Biological Opinion, September 21. 24 pp.

National Marine Fisheries Service. 1993c. Endangered Species Act section 7 consultation on proposed management activities conducted under Amendment

5 to the Northeast Multispecies Fishery Management Plan. Biological Opinion, November 30. 46 pp.

National Marine Fisheries Service. 1989. Endangered Species Act section 7 consultation concerning the issuing of exemptions for commercial fishing

operations under section 114 of the Marine Mammal Protection Act. Decision Memorandum. July 5.

National Marine Fisheries Service. 1988. Endangered Species Act section 7 consultation biological opinion: Removal of certain outer continental shelf

oil and gas structures in the Gulf of Mexico by the Minerals Management Service. Office of Protected Resources, National Marine Fisheries Service,

Silver Spring, Maryland 20910. Signed July 25, 1988. [Consultation No. SER/1988/0026].

Newsday. 2000. 43 turtles and a whale found dead. Newsday Newspaper Monday August 7, 2000:2.

Panou, A. S. Moschonas, L. Tselentis, and N. Voutsinas. 1991. Incidental catches of loggerhead turtles, Caretta caretta, in swordfish long lines in the

Ionian Sea, Greece. Institute of Zoology, University of Munich, Seidlstrasser 25, 8000 Munich 2, Germany. Unpublished Report. 6 pp.

Panou, A., G. Antypas, Y. Giannopoulos, S. Moschonas, D., G. and Ch. Mourelatos, P. Toumazatos, L. Tselentis, N. Voutsinas, and V. Voutsinal. 1992.

Incidental catches of loggerhead turtles, Caretta caretta, in swordfish long lines in the Ionian Sea, Greece. Institute of Zoology. University of

Munich, Seidlstrasser 25, 8000 Munich 2, Germany. Unpublished Report. 8 pp.

Prescott, R.L. 1988. Leatherbacks in Cape Cod Bay, Massachusetts, 1977-1988. NOAA Tech. Memo. NMFS-SEFSC-214: 83-84.

Ramirez, P.A.U. and L.V.G. Ania. 2000. Incidence of marine turtles in the Mexican long-line tuna fishery in the Gulf of Mexico. NMFS-SEFSC Tech. Memo.

436:110.

Reichart, H.A. and J. Fretey. 1993. WIDECAST sea turtle recovery action plan for Suriname. CEP Tech. Rep. 24: 65 pp. ENEP Caribbean Environment

Programme, Kingston, Jamaica.

Rivera, Maria Calixta Ortiz. 2000. Evaluacion de varamientos y mortandad de tortugas marinas en Puerto Rico e Islas Virgenes. Masters Thesis. PP. 81.

Schroeder, B.A. 1994. Florida index nesting beach surveys: are we on the right track? U.S. Dep. Commer. NOAA Tech. Memo. NMFS-SEFSC-351:

132-133.

Scott, N. and J.A. Horrocks. 1993. WIDECAST sea turtle recovery action plan for St. Vincent and the Grenadines. CEP Tech. Rep. 27: 80pp. UNEP

Caribbean Environment Programme, Kingston, Jamaica
289

Silvani, L., M. Gazo, A. Aguilar. 1999. Spanish driftnet fishing and incidental catches in the western Mediterranean. Biological Conservation 90: 79-85.

Smith, G.W., K.L. Eckert, and J.P. Gibson. 1992. WIDECAST sea turtle recovery action plan for Belize. CEP tech. Rep. 18: 86 pp. UNEP Caribbean

Environment Programme, Kingston, Jamaica.

Spotila, J.R., P.T. Plotkin, and J.A. Keinath. 1998. In water population survey of sea turtles of Delaware Bay. Final Report to NMFS, Office of Protected

Resources for Work Conducted Under Contract #43AANF600211 and NMFS Permit No. 1007. 21 pp.

Sybesma, J. 1992. WIDECAST sea turtle recovery action plan for the Netherlands Antilles. CEP Tech. Rep. 11: 63 pp. UNEP Caribbean Environment

Programme, Kingston, Jamaica.

Tobias, W. 1991. Turtles caught in Caribbean swordfish net fishery. Marine Turtle Newsletter 53: 10-12.

Yeung, C., S.P. Epperly, and C.A. Brown. 2000. Preliminary revised estimates of marine mammal and marine turtle bycatch by the U.S. Atlantic pelagic

longline fleet, 1992-1998. NMFS, Miami Laboratory PRD Contribution Number 99/00-13.
290

Table 2. Summary of observed, estimated, incidental, (lethal), and [strandings] take levels, sea turtle life stage, and geographic

region for generalized activities impacting sea turtles in the U.S. Atlantic, Caribbean and Gulf of Mexico. Reader should refer to

Table 1 for details and references.

Annual Observed, Estimated, Incidental (Lethal ) and [Strandings] Take Levels

Generalized Activities

Loggerhead Leatherback Green Kemp’s Hawksbill Olive Ridley

Life Stage

Geographic

Region

Military 287(69) 277(59) 278(60) 277(59) 277(59) 0 Adult, Immature Atlantic

91(91) 17(17) 16(16) 16(16) 4(4) 0 Adult, Immature Atlantic, Gulf of

Mexico

Channel Maintenance (Dredging and

Blasting: ACOE)

65(65) 3(3) 15(15) 14(14) 3(3) 0 Adult, Immature Atlantic

38(38) 5(5) 13(13) 19(19) 7(7) 0 Adult, Immature Gulf of Mexico

Oil Activities - Lease Sales, Seismic

Surveys, Rig Removal: MMS, ACOE82

12(12) 7(7) 7(7 7(7) 7(7) 0 Adult, Immature Gulf of Mexico

Nuclear Power Plants

145-unlim.

(17)

105-unlim.

(2)

112-unlim.

(10)

113-

unlim.(6)

105-

unlim.(2)

0 Adult, Immature Atlantic

Fisheries

 Gillnets

142(86),

52(12), 7-

50(1-17),

51.0(7.4),

[14]

8(8), 6(2)

5-27(2-12)

78(42),

34(12),

0-4(0-3),

93.1(43.5)

[9]

196(100),

10(0), 1-

5(1-3),

34.5(28.3)

[24]

4(4), 1(0) 0 Adult, Immature Atlantic

1(0) 1(0) 9(5) 7(3) 0 0 Adult, Immature Gulf of Mexico

421(1)

16,236

2(0) 0 0 0 0 Adult, Immature Mediterranean

[43] [0] [0] [0] [0] [0] Adult Caribbean
291

 Longline 468(7)

931(1)

0.0046-

0.0218/1,

000

hooks

358(6)

918(0)

0.0116-

0.1183/1,

000

hooks

46(2) 23(1) 46(2) 0 Adult, Immature Atlantic, Gulf of

Mexico

12(12) 2(2) 2(2) 2(2) 2(2) 0 Adult, Immature Atlantic,

Caribbean, Gulf

of Mexico

8-119(0) 2-45(0) 0-2(0) 0 0 0 Adult, Immature Atlantic

45(2) 2 0 1 4 0 Adult, Immature Gulf of Mexico

3956(0)

3453-

22,487

(500-600)

11 0 0 0 0 Immature Mediterranean

 Trawling

3450(3450) 650(650) 3450(3450) 3450(3450) 3450(3450) 0 Adult, Immature Atlantic, Gulf of

Mexico

32(30)

102(13) 3-

16(1-4)

2(1) 2(1) 2(1) 2(1) 0 Adult, Immature Atlantic

19(3) 0 4(0) 47(9) 2(0) 0 Adult, Immature Gulf of Mexico

15 6 16 0 11 0 Adult, Immature Caribbean

 Pound Net

398(1)

2898

4(0) 73(3) 

531

71(0) 

221

0 0 Adult, Immature Atlantic

 Hook-and-Line 82

95(2) 1(0) 33(0) 28(0) 0 0 Adult, Immature Atlantic

10(1) 0 10(1) 415(91) 4(0) 0 Immature Gulf of Mexico

0 0 0 0 2(0) 0 Immature Caribbean
292

 Scallop Dredge

0-1(0) 0 0 0 0 0 Adult, Immature Atlantic

 Pot/Trap

10(10)

5(0)

4(4) 

11(0) [201]

0 

1(0)

0 0 0 Adult, Immature Atlantic

1(1) 0 0 0 0 0 Adult Gulf of Mexico

0 0 2(1) 0 0 0 Immature Caribbean

 Bottom Set Line

500 0 0 0 0 0 Immature Atlantic

 Set Net

1(0) 0 12(0) 1(0) 0 0 Immature Atlantic

0 0 0 1(0) 1(1) 0 Immature Gulf of Mexico

 Cast Net

0 0 1(0) 0 0 0 Immature Atlantic

0 0 3(0) 0 0 0 Immature Gulf of Mexico

 Trot Line

0 0 1(0) 0 0 0 Immature Gulf of Mexico

 Seine Net

15(1) 0 0 1(0) 0 0 Adult, Immature Atlantic

2(0) 0 3(0) 1(0) 0 0 Adult, Immature Gulf of Mexico

 Stop Net

No Data No Data No Data No Data No Data 0 Adult, Immature Atlantic

 Purse Seine

No Data No Data No Data No Data No Data 0 Adult, Immature Atlantic

 Fly Net

No Data No Data No Data No Data No Data 0 Adult, Immature Atlantic

 Channel Net

2(0) 1(0) 1(0) 1(0) 0 0 Immature Atlantic

 Try Net

1(0) 0 2(0) 0 0 0 Immature Atlantic

0 0 0 1(0) 0 0 Unknown Gulf of Mexico
293

 Unknown/Miscellaneous Gear

11(3) 1(0) 2(0) 1(0) 2(0) 0 Adult, Immature Atlantic

0 0 2(0) 6(1) 0 0 Immature Gulf of Mexico

0 0 2(0) 0 0 0 Immature CaribbeanError

! Bookmark

not defined.

Fisheries Utilizing Multiple Gears

 Bluefish (Gillnets, pound nets,

trawls, troll lines) 6(3) 0 0 6(6) 0 0 Adult, Immature Atlantic

 Herring (gill net, purse seine,

trawl) 6(3) 1(1) 1(1) 1(1) 0 0 Adult, Immature Atlantic

 Mackerel, Squid, Butterfish

(dredge, gill net, longline, pot/trap, purse

seine, trawl)

6(3) 1(1) 2(2) 2(2) 0 0 Adult, Immature Atlantic

 Monkfish (dredge, gill net,

longline, pot/trap, trawls) 6(3) 1(1) 1(1) 1(1) 0 0 Adult, Immature Atlantic

 Dogfish (gill net, trawl)

6(3) 1(1) 1(1) 1(1) 0 0 Adult, Immature Atlantic

 Summer Flounder, Scup and

Black Sea Bass ( hook-and-line, longline,

trawl)

15(5) 3(3) 3(3) 3(3) 3(3) 3(3) Adult, Immature Atlantic

 Weakfish (gill net, hook-andline, trawl) 20(20) 0 0 2(2) 0 0 Adult, Immature Atlantic

Research

1028,

198(0)

21, 4(0) 1102,

84(0)

176, 68(1) 28, 5(0) 0 Adult, Immature Atlantic

1740,

574(0)

30 0 35 0 0 0 0 Hatchlings Atlantic

425, 5(0) 10, 0 710, 2(0) 496, 47(0) 60, 0 0 Adult, Immature Gulf of Mexico

1000 (10) 400 (10) 1000(10) 4000(10) 4000(10) 0 Hatchling Gulf of Mexico
294

50, 6(0) 13, 4(0) 315, 81(0) 5, 0 325, 37(0) 0 Adult, Immature Caribbean

Beach Activities - beach nourishment,

beach ligthting, beach construction,

groins, beach driving, etc.

No Data No Data No Data No Data No Data No Data Adult, Hatchling Atlantic, Gulf of

Mexico

Rehabilitation

No Data No Data No Data No Data No Data No Data Adult, Immature Atlantic, Gulf of

Mexico

20 0 50 50 30 0 Adult, Immature Gulf of Mexico

15 0 0 0 0 0 Hatchling Atlantic

Entanglements

No Data No Data No Data No Data No Data No Data Adult, Immature Atlantic

[0] [1]/[13] [9]/[13] [0] [3]/[13] 0 Adult, Immature Caribbean

No Data No Data No Data No Data No Data No Data Adult, Immature,

Hatchling

Caribbean

Boat Strikes82

[0] [0]/[42] [38]/[42] [0] [4]/[42] 0 Adult, Immature Caribbean

Poaching

[0] [4]/[16] [4]/16] [0] [8]/[16] 0 Adult, Immature Caribbean

No Data No Data No Data No Data No Data No Data Adult, Immature,

Egg

Caribbean

Ingestion

No Data No Data No Data No Data No Data No Data Adult Caribbean

Foreign Countries Utilizing Multiple

Gears

 West Africa (nets, hook, hand

No Data No Data No Data No Data No Data No Data

 Nicaragua (gill net, spear)

No Data No Data No Data No Data No Data No Data

 Belize (gill net, harpoon, hook,

spear) No Data No Data No Data No Data No Data No Data
295

 Suriname (drift net, hand, trawl,

set net, ) No Data No Data No Data No Data No Data No Data

 Antigua/Barguda (gill net,

longline trammel net, seines) No Data No Data No Data No Data No Data No Data

 St. Lucia ( hand, net)

No Data No Data No Data No Data No Data No Data

 St. Kitts and Nevis (gill net, hand,

seines, turtle nets) No Data No Data No Data No Data No Data No Data

 St. Vincent and the Grenadines

(longline, spear gun, turtle nets) No Data No Data No Data No Data No Data No Data

 Netherland Antilles (longline,

purse seine, spear gun) No Data No Data No Data No Data No Data No Data

 Aruba (longline, seine)

No Data No Data No Data No Data No Data No Data

 Barbados (hand, net, spear)

No Data No Data No Data No Data No Data No Data

 British Virgin Isles (longline, 

net) No Data No Data No Data No Data No Data No Data

ACKNOWLEDGEMENTS

The authors gratefully acknowledge the following people for providing information in a timely manner:

Florida Fish and Wildlife Conservation Commission - Beth Morford

Georgia Department of Natural Resources - Mark Dodd

Long Island University - Samuel Sadove

Massachusetts Audubon Society’s Wellfleet Bay Wildlife Sanctuary - Robert Prescott

National Marine Fisheries Service - David Bernhart, Donna Brewer, Andrea Cannon, Therese Conant, Eric Hawk, Terri Jordan, Mi Ae Kim, Jennifer Lee,

Carrie McDaniel, Richard Merrick, Cheryl Ryder, Mike Tork, and Kathy Wang.

New Brunswick Museum, Canada - Donald McAlpine

North Carolina Wildlife Resources Commission - Ruth Boettcher

Puerto Rico Department of Natural Resources - Carlos Diez

South Carolina Department of Natural Resources - David Cupka, Sally Murphy

Texas Parks and Wildlife Department - Rosie Roegner

U.S. Fish and Wildlife Service - Robyn Cobb, Debbie Fuller, Donna Griffin, Diane Lynch, Sandy Macpherson, Karen Mayne, Donald Palmer, Linda Duran

Poole, Marelisa Rivera, Cindy Schultz, and Teresa Tallevast.
296

U.S. Geological Survey - Donna Shaver

U.S. Virgin Island National Park - Rafe Boulon

Virginia Institute of Marine Sciences - Katherine Mansfield

 

1

 Number in parenthesis represents lethal take and is a subset of the total incidental take; numbers less than whole are rounded up. 

2

 The incidental take level may represent any combination of species and thus is tallied under each column (note: in most cases, it is expected that takes of turtle species other than loggerheads will be minimal.

3

Includes Navy Operations along the Atlantic Coasts and Gulf of Mexico, Mine warfare center, Eglin AFB, Moody AFB

4

 Total incidental take level includes acoustic harassment.

5

 Up to 8 turtles total, of which, no more than 5 may be leatherbacks, greens, Kemp’s or hawksbill, in combination

6

 Total incidental take is 3 turtles of any combination over a 30-year period

7 Not to exceed 25 turtles, in total.

8

 Represents range of observed takes (range of observed lethal takes) for 1995-1999 data.

9

 Merrick, R. 2000. National Marine Fisheries Service, Northeast Fisheries Science Center, NE Observer Program data. Personal Communication to J Braun-McNeill. (Fax) November 28, 2000.

10 Tork, M. 2000. National Marine Fisheries Service, Northeast Fisheries Science Center, NE Observer data. Personal Communication to J. Braun-McNeill. (Fax) November 29 & December 8, 2000.

11 Incidental take level for post-hatchlings for total period June 21, 1999 through January 2001

12 Represents estimated incidental take levels, however the Incidental take statement cites observed take (5 loggerheads, 2 leatherbacks, or 3 Kemp’s ridleys or greens or hawksbills in any combination) as a representative of the

incidental take. The incidental take represents any combination of species other than the leatherback.

13 Represents incidental (observed lethal) take

14 Represents estimated (observed lethal) take for 1999 data only

15 Represents incidental (incidental lethal) take

16 Incidental take levels for non-lethal were not identified because entrainment is a function of turtle abundance & environmental conditions; lethal take is also expressed as 1.5% of the total number entrained in the plant,

whichever is greater. Represents a minimum number of turtles taken annually because the majority of the take is observed take and is not an estimate of true numbers that are taken; the ‘unlimited’ lethal take for St.Lucie Power

Plant is not incorporated in the Total. The numbers for each species are not additive because the total incidental take, in many cases, represents a combination of species.

17 NERO is in the process of reinitiating Oyster Creek

18 No report of take available to date; new research for FY00

19 Numbers represent Incidental Live Take - Estimated Lethal Take - Strandings

20 FWS allows for 7% of nests needing relocation to be missed based on Schroeder, 1994.

21 Fuller, D. 2000. Fish and Wildlife Service, Lafayette Field Office, Lafayette, LA . Personal Communication to J Braun-McNeill. (Phone) December 12, 2000.

22 Palmer, D. 2000. Fish and Wildlife Service, Jacksonville Field Office, Jacksonville, FL. Personal Communication to J Braun-McNeill. (Phone) December 8, 2000.

23 Max number of eggs to be removed (number of eggs allowed broken) each year

24 FWS recommends activities be undertaken and completed between mid-Sept and March 31 to avoid impacting nesting sea turtles.

25 Boettcher, R. 2000. North Carolina Wildlife Resources Commission, Gloucester, NC. Personal Communication to J. Braun-McNeill. (Email) November 28, 2000.

26 Murphy, S. 2000. South Carolina Department of Natural Resources, Charleston, SC. Personal Communication to J. Braun-McNeill. (Phone) November 27, 2000.

27 Dodd, M. 2000. Georgia Department of Natural Resources, Brunswick, GA. Personal Communication to J. Braun-McNeill. (Fax) December 8, 2000.

28Morford, B. 2000. Florida Fish and Wildlife Conservation Commission, Tequesta, Florida. Personal Communication to J. Braun-McNeill (Email) November 28, 2000.

29 Griffin, D. 2000. US Fish and Wildlife Service, US Virgin Islands. Personal Communication to J. Braun-McNeill (phone) January 29, 2001.

30 Diez, C. 2000. Programa de Especies Protegidas DRNA-PR San Juan, Puerto Rico. Personal Communication to J. Braun-McNeill (phone) December 7, 2000.

31 1999 was first year a loggerhead was reported captured by inshore dragger; state waters closed to trawling May-Oct

32Prescott R. 2000. Massachusetts Audubon Society's Wellfleet Bay Wildlife Sanctuary South Wellfleet, MA Personal Communication to J. Braun-McNeill (Email) December 1, 2000

33 Numbers represent # leatherbacks stranded due to entanglement/total # leatherbacks stranded for period 1977-1996

34 200 lb leatherback captured in a weir several years ago; one dead loggerhead that washes ashore in Nantucket Sound each year assumed weir caught; 3 or 4 families that operate 12 weirs.

35 Incidental capture data for 1980-1999; numbers represent live(dead) captures

36Teas, W.G. 2000. STSSN strandings data. Personal Communication to J.Braun-McNeill (Email of strandings data). December 12, 2000. 

37 Data from 1991 survey of 213 commercial fishermen; NYDMR conducted trawl/field surveys April-Nov since 1985 especially in Peconic Gardiner’s Bay - no records of turtle takes or sightings

38 Sadove, S. 2000. Long Island University, Southampton College, Southampton, New York (Phone) December 6, 2000

39Trawling is prohibited within 2 miles of the coastline, but summer sea turtle distribution co-occurs with this fishery.

40Majority of fishing activity occurs inside Delaware Bay

41No incidental take in this fishery are known; traps may not exceed 125 cubic feet and must have escape panel

42Numbers represent estimated take - observed (lethal) take. 1997 data

43Numbers represent observed take - fate of hooked turtles not known. From 1988-2000 data
297

 

44 Braun-McNeill, J. 2000. National Marine Fisheries Service, SEFSC, Beaufort, NC, unpublished data. December 21, 2000

45 Season opens in late winter and early spring when offshore bottom waters are > 55; one criterion for closure is water temperature: whelk trawling will close for the season and not reopen throughout the State 6 days after

water temperatures first hit 64 deg F in the Fort Johnson boat slip - after 6 days have lapsed, the water temperature will be 68 deg F, the temperature at which turtles move into State waters.

46 Cupka, D. 2000. South Carolina Department of Natural Resources, Marine Resources Division, Office of Fisheries Management, Charleston, SC personal communication to J. Braun-McNeill (email of the Management Plan for

South Carolina’s Offshore Whelk Trawling Fishery - updated January 1999) December 18, 2000.

4715 min tow times, but still take turtles

48Data from 28 observed tows in 1996 (18 tows) and 1997 (10 tows); CPUE=0.3097 turtles/100ft net hour; Fishery occurs mid-Dec to 4/1 within state waters; 10 vessels fish/day; TEDS required in state waters beginning 12/00;

experimenting with a ‘topless’ net

49Numbers represent observed take (lethal + rehabilitated). 1980-1995 data

50Numbers represent #strandings due to boat strikes/total strandings

51Numbers represent #strandings due to poaching/total strandings

52Numbers represent #strandings due to entanglements/total strandings

53 Boulon R. 2000. Resource Management, V.I. National Park, US Virgin Islands (Email to Joanne Braun-McNeill) December 7, 2000

54One green turtle reported tangled in a lounge chair; turtles (unknown species) reported falling into construction pit which resulted in changes in permitting requirements for coastal construction

55Numbers represent observed take; Data from 1994-95

56Numbers represent observed take; estimated 23,520 and 15,6000 loggerhead turtles captured in 1991 and 1992, respectively.

57Data from 1986-1995.

58Data from 1981-1990; loggerheads may be caught up to 8 times.

59Data from 1981-1990; mortality 73.6%

60Data from 1978-1986

61Data from 1978-1986; numbers represent estimated captured/year; 30% mortality

62Data from 1978-1981; vessels targeting tuna caught more and smaller turtles than vessels targeting swordfish

63Data from 1988; numbers reported are estimates caught (estimated killed)

64Data from 1989-1991; estimated 70-100 turtles captured annually; multiple recaptures noted

65Suspected cause for decline in leatherbacks

66500 estimated captured annually

67Numbers are observed taken in 13,600 trawls; mortality estimated at 19%; 1370 turtles est. captured/year with 260 dead

68Green, loggerhead and hawksbill turtles are commercially harvested; landing trends ranged from 1,300 tons in 1975 to about 150 tons.

69Number of leatherbacks that washed ashore; estimated 500-1,000 adult female leatherbacks are killed in gill nets annually; many of the turtles do not drown but are butchered to get them out of the nets.

70 Eckert, S. 2000. Hubbs-Sea World Research Institute, 2595 Ingraham Street, San Diego, California. Personal Communication (telephone) to Sheryan Epperly (NOAA/NMFS/SEFSC, Miami, Florida). October 3, 2000

71Estimated “two-thirds of turtles that swim up onto the coast of Ghana are caught and slaughtered by local fishermen”.

72500-800 turtles sold annually (60% green, 30% loggerhead and 10% hawksbill); hawksbills and greens mostly captured in shrimp trawls; longline fishing for sharks “reportedly catching leatherbacks”.

73Incidental catch of green and leatherback turtles in shrimp trawls starts in Feb., peaks in March and May, ends July-Aug; net mortality is higher than trawl mortality.

74“Entanglement in pot line and longline perceived to be increasingly serious problem”; longline fishery estimated to catch “100 or more turtles each year, mostly loggerheads and leatherbacks”; hawksbill and green turtles

captured intentionally for tortoise shell and meat.

75Small numbers of nesting leatherback, green and hawksbill turtles taken; green and hawksbill turtles incidentally taken on other (seine/gill nets?) fisheries.

76Turtle nets catch green and hawksbill turtles for meat and tortoise shell; a few nesting leatherbacks caught on the beach; expanding longline fishery, but no bycatch data.

77“at least 120 turtles landed each year”, mostly green, hawksbill, and a few leatherbacks; some leatherbacks are also caught by longlines.

78An estimated 250 turtles taken annually for meat and tortoise shell; purse seine and longline vessels in area, but no bycatch data

79Small hawksbill turtles sometimes taken for tortoiseshell; foreign longline vessels in area, but no bycatch data.

801440 hawksbills harvested between 1970-1986; 400 harvested in 1990.

81Local longliners at Anegada have caught some leatherbacks

82 There was additional information of sea turtle interaction for which no quantitative data were available
APPENDIX 3

OBSERVED SEA TURTLE

CAPTURES IN THE U.S.

ATLANTIC PELAGIC LONGLINE

FISHERY, 1999-2000

Cynthia Yeung
299

No/Yes/Unknown

0/1/2

LF=left front RF=right front LR=left

rear RR=right rear

trip m d y lat deg lat min lon deg lon min species condition hook location

hook

removed entangled

line left

(ft)

CL

(cm) additional comments

W07 10 21 1999 39 53 69 51Leatherback alive, injured beak/mouth 0 0 2 150hooked in mouth

W07 10 21 1999 39 53 69 51Loggerhead alive, injured ingested (throat/esophagus) 0 0 2 60swallowed hook

W07 10 23 1999 38 37 72 48Loggerhead alive, injured head/neck (external) 0 0 2 65hooked on side of mouth

W07 10 23 1999 38 37 72 48Leatherback alive, injured unknown beak/mouth 1 0 0 150spit hook of of mouth

W07 10 26 1999 39 54 70 34Loggerhead alive, injured beak/mouth 0 0 1 80hooked in tongue

W07 10 28 1999 39 25 69 31Leatherback alive, injured not hooked 1 0 125wrapped in mainline,untangled by

crew

W07 10 31 1999 39 49 69 53Loggerhead fresh dead beak/mouth 0 0 57hooked in mouth

W07 11 1 1999 39 43 70 9Loggerhead alive, injured beak/mouth 0 0 0 60hooked in mouth,only hook left

W08 11 26 1999 37 43 74 4Loggerhead alive, injured ingested (throat/esophagus) 0 0 4 60swallowed hook

W08 11 27 1999 37 41 74 4Loggerhead alive, injured beak/mouth 1 0 0 55spit hook out of mouth, dove

immediately,no gear attached

R02 12 4 1999 35 43 74 44unknown alive, injured beak/mouth 0 0 5 150hooked in mouth

S20 11 25 1999 25 19 89 34Leatherback alive, injured flipper 0 0 2 180hooked in left front flipper

S20 11 30 1999 24 14 83 52Loggerhead alive, injured beak/mouth 0 0 2 140hooked in mouth

P50 11 13 1999 26 36 92 28unknown alive, injured beak/mouth 0 0 120line cut short, hook in side of

mouth,original id was hawksbill, but

improbable

T44 4 23 1999 32 39 72 49Loggerhead alive, injured ingested (throat/esophagus) 0 0 0 120hooked in throat

T44 4 23 1999 32 39 72 49Loggerhead alive, injured ingested (throat/esophagus) 0 0 0 70hook in throat

F67 6 15 1999 32 13 78 23Leatherback alive, injured flipper 0 0 6 152hooked in flipper

F67 6 15 1999 32 13 78 23Loggerhead alive, injured unknown beak/mouth 0 0 6 48hooked in mouth

T45 6 1 1999 32 29 78 5Leatherback alive, injured flipper 0 1 48 182hook location unknown,excellent

condition

S14 5 30 1999 39 52 54 52Loggerhead alive, injured unknown beak/mouth 1 0 0 56Lip hooked, hook removed, released

in excellent condition

S14 5 30 1999 39 52 54 52Loggerhead alive, injured flipper 1 0 0 65hooked right pectoral fin, excellent

condition

S14 5 30 1999 39 52 54 52Loggerhead alive, injured unknown beak/mouth 0 0 0 60mouth hooked,released in good

condition

S14 6 3 1999 41 36 51 25Leatherback alive, uninjured unknown other 0 1 12 170

S14 6 10 1999 42 22 51 27Loggerhead alive, injured unknown beak/mouth 0 0 2 140mouth hooked

S14 6 13 1999 41 10 51 24Leatherback alive, injured flipper 0 0 15 200right front flipper snagged
300

No/Yes/Unknown

0/1/2

LF=left front RF=right front LR=left

rear RR=right rear

trip m d y lat deg lat min lon deg lon min species condition hook location

hook

removed entangled

line left

(ft)

CL

(cm) additional comments

S14 6 16 1999 41 51 50 20Leatherback alive, injured unknown beak/mouth 0 0 179mouth hooked, some line left in with

hook

S14 6 16 1999 41 51 50 20Loggerhead alive, injured unknown beak/mouth 0 0 100mouth hooked, some line left in with

hook

S14 6 16 1999 41 51 50 20Leatherback alive, injured unknown beak/mouth 0 0 180mouth hooked, some line left in with

hook

S14 6 17 1999 42 1 50 25Loggerhead alive, injured unknown beak/mouth 0 0 4 90mouth hooked

S14 6 18 1999 41 59 50 24Loggerhead alive, injured ingested (throat/esophagus) 0 0 3 80hook swallowed

S14 6 18 1999 41 59 50 24Loggerhead alive, injured unknown beak/mouth 0 0 2 65mouth hooked

S14 6 18 1999 41 59 50 24Loggerhead alive, injured unknown beak/mouth 0 0 4 80mouth hooked

S14 6 18 1999 41 59 50 24Loggerhead alive, injured ingested (throat/esophagus) 0 0 4 100swallowed hook

S14 6 18 1999 41 59 50 24Loggerhead alive, injured unknown beak/mouth 0 0 0 80mouth hooked

S14 6 19 1999 42 3 50 22Loggerhead alive, injured unknown beak/mouth 0 0 10 70mouth hooked

S14 6 20 1999 42 14 50 44Loggerhead alive, injured unknown beak/mouth 0 0 120mouth hooked, seemed in very bad

shape

S14 6 22 1999 42 24 50 48Leatherback alive, injured flipper 0 0 200tail? hooked,swam off strong

S14 6 22 1999 42 24 50 48Loggerhead alive, injured ingested (throat/esophagus) 0 0 90hook swallowed

S14 6 23 1999 42 24 50 38Loggerhead alive, injured flipper 0 0 90tail hooked

S14 6 23 1999 42 24 50 38Loggerhead alive, injured ingested (throat/esophagus) 0 0 90hook swallowed

S14 6 23 1999 42 24 50 38Loggerhead alive, injured ingested (throat/esophagus) 0 0 110hook swallowed

S14 6 23 1999 42 24 50 38Loggerhead alive, injured ingested (throat/esophagus) 0 0 125hook swallowed, seemed in very bad

shape

S10 1 27 1999 28 0 79 25Leatherback alive, injured flipper 0 1 6 200hooked in right pectoral fin

S10 1 30 1999 28 0 79 25Leatherback alive, injured head/neck (external) 0 0 12 200hooked by mouth

P43 3 1 1999 26 14 91 34unknown other, unknown unknown other 0 1 20 tangled, maybe hooked but not in

mouth

N34 2 27 1999 20 29 73 50Loggerhead alive, injured unknown beak/mouth 0 0 1 70hooked in mouth

N34 2 28 1999 20 25 75 50Loggerhead alive, injured unknown beak/mouth 0 0 3 80hooked in mouth

N34 2 28 1999 20 25 75 50Loggerhead alive, uninjured not hooked 1 0 85entangled in flipper,all line removed

N34 3 1 1999 20 27 73 50Leatherback alive, injured unknown beak/mouth 0 0 2 100hooked in mouth

N34 3 4 1999 20 25 73 52Loggerhead alive, injured unknown beak/mouth 0 0 2 100hooked in mouth

N34 3 4 1999 20 27 73 50Leatherback alive, injured flipper 0 0 2 110hooked in left front flipper

N34 3 9 1999 20 25 73 52Loggerhead alive, injured unknown beak/mouth 0 0 3 65hooked in mouth
301

No/Yes/Unknown

0/1/2

LF=left front RF=right front LR=left

rear RR=right rear

trip m d y lat deg lat min lon deg lon min species condition hook location

hook

removed entangled

line left

(ft)

CL

(cm) additional comments

W03 4 22 1999 28 37 79 29Leatherback alive, injured unknown beak/mouth 0 0 9 160hooked in mouth

Q09 8 11 1999 31 45 79 5Leatherback alive, uninjured unknown other 0 0 60 dove as boat approached, line cut at

clip,not known tangled or hooked

F69 7 16 1999 45 45 43 1Loggerhead alive, injured unknown beak/mouth 0 0 6 71mouth hooked

F69 7 16 1999 45 45 43 0Loggerhead alive, injured unknown beak/mouth 0 0 6 56mouth hooked

F69 7 16 1999 45 45 43 4Loggerhead alive, injured unknown beak/mouth 1 0 0 51mouth hooked

F69 7 17 1999 46 4 43 35Loggerhead alive, injured unknown beak/mouth 0 0 4 64mouth hooked

F69 7 17 1999 46 4 43 35Loggerhead alive, injured unknown beak/mouth 0 0 6 71mouth hooked

F69 7 17 1999 46 4 43 35Loggerhead alive, injured flipper 0 0 0 48

F69 7 19 1999 46 6 43 14Loggerhead alive, injured unknown beak/mouth 1 0 0 46mouth hooked

F69 7 19 1999 46 6 43 14Loggerhead alive, injured unknown beak/mouth 0 0 3 66mouth hooked

F69 7 19 1999 46 6 43 14Loggerhead alive, injured unknown beak/mouth 0 0 3 71mouth hooked

F69 7 19 1999 46 6 43 14Leatherback alive, injured unknown beak/mouth 0 0 12 183mouth hooked

F69 7 19 1999 46 6 43 14Loggerhead alive, injured unknown beak/mouth 0 0 6 71mouth hooked

F69 7 20 1999 46 6 43 1Loggerhead alive, injured unknown beak/mouth 0 0 6 69mouth hooked

F69 7 20 1999 46 6 43 1Loggerhead alive, injured unknown beak/mouth 0 0 6 69mouth hooked

F69 7 20 1999 46 6 43 1Loggerhead alive, injured unknown beak/mouth 0 0 2 71mouth hooked

F69 7 20 1999 46 6 43 1Leatherback alive, uninjured not hooked 1 0 168tangled in radio buoy drop rope,

untangled completely

F69 7 21 1999 45 59 42 46Leatherback alive, injured flipper 0 0 9 183

F69 7 21 1999 45 59 42 46Leatherback alive, injured unknown beak/mouth 0 0 10 152mouth hooked

F69 7 21 1999 45 59 42 46Loggerhead alive, injured unknown beak/mouth 0 0 4 69mouth hooked

F69 7 21 1999 45 59 42 46Leatherback alive, injured flipper 0 1 12 168

F69 7 22 1999 42 2 42 36Loggerhead other, unknown unknown other 66did not see capture or release

F69 7 22 1999 46 2 42 36Leatherback other, unknown unknown other 168did not see capture or release, id by

captain

F69 7 22 1999 46 2 42 36Leatherback other, unknown unknown other 168did not see capture or release

F69 7 22 1999 46 2 42 36Leatherback alive, injured unknown beak/mouth 0 0 12 183mouth hooked

F69 7 22 1999 46 2 42 36Leatherback other, unknown unknown other 183did not see capture or release

F69 7 22 1999 46 2 42 36Leatherback alive, uninjured not hooked 1 0 168tangled in mainline, line cut

F69 7 26 1999 46 18 42 39Loggerhead alive, injured unknown beak/mouth 0 0 4 66mouth hooked

F69 7 27 1999 46 9 42 21Loggerhead alive, injured head/neck (external) 0 0 8 183
302

No/Yes/Unknown

0/1/2

LF=left front RF=right front LR=left

rear RR=right rear

trip m d y lat deg lat min lon deg lon min species condition hook location

hook

removed entangled

line left

(ft)

CL

(cm) additional comments

F69 7 28 1999 46 9 41 53Loggerhead alive, injured unknown other 0 0 18 183did not see capture

F69 7 28 1999 46 9 41 53Loggerhead alive, injured unknown beak/mouth 0 0 3 66mouth hooked

F69 7 28 1999 46 9 41 53Leatherback other, unknown unknown other 168did not see capture or release

F69 7 28 1999 46 9 41 53Leatherback other, unknown unknown other 122did not see capture or release

F69 7 28 1999 46 9 41 53Loggerhead alive, injured unknown beak/mouth 0 0 6 64mouth hooked

F69 7 28 1999 46 9 41 53Leatherback alive, uninjured not hooked 1 24 168tangled in mainline and buoy

drop;untangled from mainline,but

bullet buoy and buoy drop remained

tangled on animal

F69 7 29 1999 46 0 41 33Loggerhead alive, injured unknown beak/mouth 0 0 4 69mouth hooked

F69 7 29 1999 46 0 41 33Loggerhead alive, injured unknown beak/mouth 0 0 4 61mouth hooked

F69 7 29 1999 46 0 41 33Loggerhead other, unknown unknown other 64did not see capture or release

F69 7 29 1999 46 0 41 33Loggerhead alive, injured unknown beak/mouth 0 0 3 56mouth hooked, animal remained on

the surface of the water

F69 7 29 1999 46 0 41 33Leatherback alive, uninjured not hooked 1 0 152mainline tangled around

neck,untangled from

mainline,remained on the surface with

head above surface

F69 7 29 1999 46 0 41 33Leatherback alive, injured unknown other 0 0 12 168hooked unknown, remained just below

surface

F69 7 29 1999 46 0 41 33Leatherback alive, injured flipper 0 0 12 183

F69 7 29 1999 46 0 41 33Leatherback alive, uninjured not hooked 1 0 168tangled in mainline around neck and

flipper, untangled completely

F69 7 29 1999 46 0 41 33Leatherback alive, injured flipper 0 12 168

F69 7 29 1999 46 0 41 33Leatherback other, unknown unknown other 168did not see capture or release

F69 7 29 1999 46 0 41 33Leatherback alive, injured not hooked 1 0 152tangled in mainline,gangion line and

buoy drop,line cut at boat side

F69 7 30 1999 46 11 41 51Leatherback alive, injured unknown beak/mouth 0 0 10 183mouth hooked

F69 7 30 1999 46 11 41 51Loggerhead alive, injured unknown beak/mouth 0 0 6 66mouth hooked

F69 7 30 1999 46 11 41 51Leatherback alive, injured flipper 0 0 5 183flipper hooked

F69 7 30 1999 46 11 41 51Leatherback alive, injured flipper 0 0 6 183flipper hooked

F69 7 31 1999 46 5 41 33Leatherback other, unknown unknown other 168did not see capture or release

F69 7 31 1999 46 5 41 33Leatherback alive, injured flipper 0 0 15 168flipper hooked
303

No/Yes/Unknown

0/1/2

LF=left front RF=right front LR=left

rear RR=right rear

trip m d y lat deg lat min lon deg lon min species condition hook location

hook

removed entangled

line left

(ft)

CL

(cm) additional comments

F69 7 31 1999 46 5 41 33Leatherback alive, uninjured not hooked 1 0 183tangled in drop buoy, cut loose

completely

F69 8 3 1999 46 15 41 54Leatherback alive, injured flipper 0 0 6 152flipper hooked

F69 8 3 1999 46 15 41 54Loggerhead alive, injured unknown beak/mouth 0 0 5 71mouth hooked

S17 10 2 1999 28 1 79 38Loggerhead alive, injured beak/mouth 0 0 6 100hooked in mouth

S18 10 22 1999 31 36 78 50Loggerhead alive, injured beak/mouth 0 0 6 110hooked in mouth

W07 10 21 1999 39 53 69 51Loggerhead alive, injured beak/mouth 0 0 2 75hooked in tongue

W07 10 21 1999 39 53 69 51Loggerhead alive, injured unknown beak/mouth 1 0 0 75spit hook out of mouth

W07 10 21 1999 39 53 69 51Leatherback alive, injured flipper 0 0 2 135hooked in right front flipper

M01018 1 16 2000 18 6 54 52Loggerhead alive, injured head/beak 0 0 0.5 95beak hooked;swam away strongly

M01018 1 18 2000 17 52 53 45Loggerhead alive, injured ingested (throat/esophagus) 0 0 1 90gut hooked;swam away strongly

T01049 1 19 2000 27 50 91 21Loggerhead alive, injured unknown other 0 0 210 condition unknown

M01018 1 22 2000 17 55 53 8Loggerhead alive, injured flipper 0 0 0.5 90LF flipper hooked;swam away strongly

M01018 1 22 2000 17 56 53 8Loggerhead alive, injured head/beak 0 0 0.2 90beak hooked;swam away strongly

M01018 1 23 2000 18 20 53 20Leatherback alive, injured unknown other 0 0 20 180large turtle could not be brought

alongside;not hooked in head

S01022 2 12 2000 28 15.5 74 10.7Loggerhead alive, injured unknown other 2 0 ? 60minor injury caused by hook;hook in

mouth,not past cavity;lengths

estimated; ventral side not seen

S01023 3 8 2000 31 54.2 78 50.1Leatherback alive, injured beak/mouth 0 0 10 150hooked in mouth;swam off readily

S01023 3 9 2000 31 51.2 78 42.1Leatherback alive, injured beak/mouth 0 0 30 170hooked in mouth;lip shank visible;

released alive and energetic

Q02005 3 21 2000 27 35.3 90 9.9Leatherback alive, injured flipper 0 0 5 122hooked in RF flipper

Q02005 3 22 2000 27 38.2 90 3.6Loggerhead alive, injured head/beak 0 0 3 90released with hook inside of beak

R01005 4 15 2000 28 28 79 3unknown alive, injured ingested (throat/esophagus) 0 0 0 0unidentified due to dangerous weather

and conditions;fairly sure it was

loggerhead

R01005 4 17 2000 28 16 78 55Loggerhead alive, injured ingested (throat/esophagus) 0 0 6 125

S01025 4 18 2000 28 39.1 79 3.8Loggerhead alive, injured ingested (throat/esophagus) 0 0 6 100hooked in throat;exhibited some

difficulty breathing;swam off readily
304

No/Yes/Unknown

0/1/2

LF=left front RF=right front LR=left

rear RR=right rear

trip m d y lat deg lat min lon deg lon min species condition hook location

hook

removed entangled

line left

(ft)

CL

(cm) additional comments

S01025 4 21 2000 28 43.1 78 45.7Loggerhead alive, injured beak/mouth 0 0 2 140hooked in mouth;shank fully visible;

seemed fine

A25006 4 22 2000 36 8 74 39Loggerhead alive, injured unknown other 1 0 0 61came off hook and swam away as it

was pulled to boat head first

P01055 5 16 2000 26 50 89 34Leatherback alive, injured carapace/plastron 0 0 1 0very strong;appeared healthy; hooked

under edge of shell midway,right side

J02001 5 28 2000 31 40 78 40unknown alive, injured unknown other 0 1 6 90leader was wrapped around LR

flipper; when it broke there was ~6' of

line and a dead dolphin fish attached

but turtle swam away fine;unsure

about i.d.

J02001 5 29 2000 31 45 79 40Loggerhead alive, injured beak/mouth 0 0 1 70hooked in top of mouth;line cut as

close to mouth as possible but could

not remove hook without further

injuring turtle;swam away and seemed

fine

K02001 5 31 2000 28 5 79 30unknown alive, injured beak/mouth 1 0 0 90hooked in mouth;not entangled;freed

itself at boat;no gear attached when

dove

 P01056 6 5 2000 27 11 91 22Leatherback alive, injured beak/mouth 0 0 1 140

P01056 6 7 2000 27 7 89 30unknown alive, injured unknown beak/mouth 0 0 12 0turtle pulled hard against leader

P01056 6 11 2000 26 29 90 11unknown alive, injured unknown other 0 0 20 0turtle not brought close enough to

ascertain condition,except it was alive

B56038 6 11 2000 37 56 68 46Leatherback alive, injured unknown other 0 1 45 120turtle surfaced ~15 yds from

vessel;cannot see where hooked; line

cut;swam away uninjured

P01056 6 12 2000 26 58 89 46Leatherback alive, injured carapace/plastron 0 0 3 120released at boat; short line; swam

away strongly

P01056 6 14 2000 27 23 89 50Leatherback alive, injured beak/mouth 0 0 2 120hook in joint of jaws
305

No/Yes/Unknown

0/1/2

LF=left front RF=right front LR=left

rear RR=right rear

trip m d y lat deg lat min lon deg lon min species condition hook location

hook

removed entangled

line left

(ft)

CL

(cm) additional comments

J02003 7 12 2000 43 35 45 30Loggerhead alive, injured beak/mouth 0 0 0 53hooked in front of beak;netted and

brought on board;biopsy punch

sample of RR flipper;cut line from

hook and left hook in turtle;swam

away strongly

J02003 7 12 2000 43 31 45 37Loggerhead alive, injured flipper 1 0 0 51hooked in RF flipper;biopsy in RR

flipper;tagged,measured;removed

hook and line;seemed fine at release

J02003 7 12 2000 43 31 45 38Loggerhead alive, injured beak/mouth 1 0 0 59hooked in beak;biopsied and tagged

RR filipper;hook and line

removed;swam away strong

J02003 7 15 2000 43 11 51 20Leatherback alive, injured flipper 0 0 4 120caused a large tangle in the

gear;hooked in the RF flipper and was

pulling hard;swam away quickly

J02003 7 15 2000 43 13 51 24Leatherback alive, injured flipper 0 0 0 150hooked in right shoulder;leader broke

at hook;quickly swam away

J02003 7 30 2000 48 40 43 4Leatherback alive, injured flipper 0 0 2 120hooked in right front shoulder;swam

away quickly

Q02009 7 31 2000 26 39 92 29.1Leatherback alive, injured head/neck (external) 0 0 4 122injury considered minor;likely to

survive;hooked in ventral neck area

near carapace;swam away actively;no

tags noticed;sub-adult

J02003 8 2 2000 49 25 42 27Loggerhead alive, injured ingested (throat/esophagus) 0 0 0 55swallowed bait (squid);brought on

board in net; measured, tagged,

biopsied each rear flipper;line cut

even with mouth; id according to

guide book

J02003 8 2 2000 49 25 42 24Leatherback alive, injured unknown other 0 0 5 150came up for air during haul-in; positive

id; swam under boat and did not

resurface; broke leader ~3' below

swivel and swam away; believed foul

hooked from the way it was pulling
306

No/Yes/Unknown

0/1/2

LF=left front RF=right front LR=left

rear RR=right rear

trip m d y lat deg lat min lon deg lon min species condition hook location

hook

removed entangled

line left

(ft)

CL

(cm) additional comments

P01057 8 4 2000 26 19 90 58Leatherback alive, injured carapace/plastron 0 0 2 130turtle was very stong;had difficulty

bringing close enough to release

O02008 8 7 2000 40 51.9 66 9.2Loggerhead alive, uninjured beak/mouth 1 0 0 72F1 tagged and released;sample LR

flipper; hook easily removed as it was

held in the mouth; no hook

penetration; no gear attached; swam

away strongly

P01057 8 7 2000 26 51 92 13.2Leatherback alive, injured carapace/plastron 0 0 20 130turtle extremely strong and

heavy;could not get turtle to surface

P01057 8 7 2000 26 51 92 13Leatherback alive, injured carapace/plastron 0 0 2 130turtle released by side of vessel; very

good condition; did not set this area

again

T01054 8 9 2000 39 54 68 48Loggerhead alive, injured ingested (throat/esophagus) 0 0 1 61throat hooked;6" leader left attached

W01013 8 9 2000 39 55 69 20Loggerhead alive, uninjured unknown other 0 0 0 45believed not hooked,just feeding on

bait,or spat out hook;turtle closely

associated with gear;believed initially

on the leader,came to surface at the

stern because vessel stopped to pull

on leader;spat out bait or escaped

gear;swam away

T01054 8 10 2000 40 4 68 40Loggerhead alive, injured beak/mouth 0 0 0 80no leader;9/0 hook left

T01054 8 11 2000 40 1 68 37Leatherback alive, injured flipper 0 0 0 152excellent condition;no leader

W01013 8 11 2000 39 52 70 28Loggerhead alive, injured beak/mouth 0 0 60 60

T01054 8 12 2000 40 0 68 59Loggerhead other, unknown unknown other 2 2 0 76recorded on individual animal log;life

history form not filled out at time of

data submission;observer could not

remember details of gear interaction

during followup questioning

T01054 8 16 2000 40 36 66 50Loggerhead alive, injured beak/mouth 0 0 2 90

W01013 8 20 2000 39 40 72 3Loggerhead alive, injured ingested (throat/esophagus) 0 0 1 50

W01013 8 22 2000 39 47 71 36Loggerhead alive, injured ingested (throat/esophagus) 0 2 45 0
307

No/Yes/Unknown

0/1/2

LF=left front RF=right front LR=left

rear RR=right rear

trip m d y lat deg lat min lon deg lon min species condition hook location

hook

removed entangled

line left

(ft)

CL

(cm) additional comments

M01020 8 25 2000 46 17.1 44 54.3Loggerhead alive, injured ingested (throat/esophagus) 1 0 0 0biopsy collected from rear flipper;

hook removed; very little bleeding;

swam away strongly

M01020 8 27 2000 44 54.8 47 3.3Loggerhead alive, injured ingested (throat/esophagus) 0 0 0 0biopsy collected from rear flipper; gut

hooked beyond view in oesophagus;

no bleeding; leader cut inside mouth;

swam away strongly

M01020 8 28 2000 44 42.5 47 23Loggerhead alive, injured ingested (throat/esophagus) 0 0 0 0biopsy "C-10" collected from rear

flipper;hook beyond view in

oesophagus;no bleeding;leader cut

deep inside mouth;swam away

vigorously

M01020 8 30 2000 44 44.2 48 23Loggerhead alive, injured ingested (throat/esophagus) 0 0 0 0hook in oesophagus,unseen;no

bleeding;leader cut as far down throat

as could be reached with

cutters;biopsy "C-1" collected from

rear flipper;more lethargic than turtles

taken in warmer water;temp@ take

60.2F; temp@ release 61.2F;swam

vigorously

M01020 9 3 2000 43 20.6 51 30.5Loggerhead alive, injured beak/mouth 1 0 0 0dipnetted aboard;lightly hooked in

beak;hook easily removed with no

bleeding with little injury;biopsy "C8";take temp 69.8F;release temp

69.9F;swam away vigorously

S01028 9 4 2000 31 28 79 1Loggerhead other, unknown unknown other 2 2 40 90leader broke before turtle was close

enough to accurately assess consition

or hook location;alive and appeared

robust
308

No/Yes/Unknown

0/1/2

LF=left front RF=right front LR=left

rear RR=right rear

trip m d y lat deg lat min lon deg lon min species condition hook location

hook

removed entangled

line left

(ft)

CL

(cm) additional comments

M01020 9 4 2000 43 13.7 51 28.9Loggerhead alive, injured ingested (throat/esophagus) 0 0 0 0gut hooked; unseen in oesophagus;no

bleeding;leader cut deep inside

mouth;biopsy "C-3";dipnetted

aboard;swam away vigorously;take

temp 68F;release temp 68.8F

Q02010 9 4 2000 26 59.5 93 46.9Leatherback alive, injured unknown other 0 0 30 0no time to estimate size before

captain cut leader

M01020 9 5 2000 43 23.7 51 39.3Leatherback alive, injured flipper 0 1 0 120hooked in leading edge of RF

flipper;several wraps of monofilament

around flipper were untangled and

removed before leader cut at

hook;swam strongly;little injury;2

hooks adjacent to each other on

flipper;not clear if hooks from same or

different sets

M01020 9 5 2000 43 14.1 51 14.5Leatherback alive, injured flipper 0 1 0 110released at surface by cutting leader

at hook; hooked RF flipper;several

wraps of monofilament were removed

before cutting leader;swam away

vigorously with little injury

S01028 9 6 2000 31 22 78 55Leatherback alive, uninjured not hooked 0 1 0 170entangled in mainline;no hook

involved;all mono removed at release

M01020 9 12 2000 43 13.9 51 27.5Leatherback alive, injured flipper 0 0 0 130RF filpper hooked;released at the

surface by cutting leader at the

hook;little injury;swam away

vigorously
309

No/Yes/Unknown

0/1/2

LF=left front RF=right front LR=left

rear RR=right rear

trip m d y lat deg lat min lon deg lon min species condition hook location

hook

removed entangled

line left

(ft)

CL

(cm) additional comments

J02004 9 20 2000 39 56 70 41Loggerhead alive, injured beak/mouth 0 0 1 60saw hooked through in lower jaw;line

cut close to hook;swam away;~60-70

lbs;hooked on single leader with no

entanglement;positive id

J02004 9 21 2000 39 47 71 20Loggerhead alive, injured beak/mouth 0 0 1 60turtle came up on single leader and

was hooked in the mouth;brown on

top;yellow on bottom;square

head;positive I.d.;~2' carapace

length;line cut close to mouth;swam

away

J02004 9 21 2000 39 46 71 34Loggerhead alive, injured beak/mouth 0 0 1 45hooked in the mouth on single

leader;brown on top and yellow on

bottom;hook stuck out from bottom of

jaw;line cut and swam away;positive

id

W01014 9 22 2000 39 53 68 27Loggerhead alive, injured beak/mouth 0 0 1 50swam away strongly upon release

J02004 9 22 2000 39 49 71 44Loggerhead alive, injured beak/mouth 0 0 1 60hooked in the mouth on single

leader;swam away looking fine

J02004 9 23 2000 39 50 71 48Loggerhead alive, injured beak/mouth 0 0 1 75hooked in right lower jaw;swam away

quickly with short piece of line sticking

out of mouth

T01055 10 6 2000 37 20 74 20Leatherback alive, injured flipper 0 0 3 152right flipper hooked; 3' 400lb mono

leader left attached;swam off in

excellent condition

T01055 10 6 2000 37 22 74 20Loggerhead alive, injured beak/mouth 0 0 6 120swam away in good condition with 6'

400 lb line and leader

T01055 10 6 2000 37 25 74 20Loggerhead alive, injured beak/mouth 0 0 5 100swam off in excellent condition with 5'

400 lb line and leader attached

J02005 10 19 2000 45 29 45 21Loggerhead alive, injured ingested (throat/esophagus) 0 0 0 61swallowed single hook;line cut even

with mouth and released;swam away

quickly;took 2 bio-tissue samples,one

from each rear flipper
310

No/Yes/Unknown

0/1/2

LF=left front RF=right front LR=left

rear RR=right rear

trip m d y lat deg lat min lon deg lon min species condition hook location

hook

removed entangled

line left

(ft)

CL

(cm) additional comments

J02005 10 19 2000 45 26 45 20Loggerhead alive, injured ingested (throat/esophagus) 0 0 0 65swallowed hook of single

leader;reddish brown with algae al

over shell;square head and 2 claws

on each rear flipper;tissue sample

from LR flipper;line cut even with

mouth and released;swam straight

down

J02005 10 19 2000 45 23 45 18Leatherback alive, injured head/neck (external) 0 0 3 120foul hooked under mouth;swam away

as soon as leader cut

J02005 10 19 2000 45 24 45 18Loggerhead alive, injured beak/mouth 1 0 0 59hooked in the mouth on a single

leader;hook removed, tagged, sample

removed from RR flipper;seemed

fine;swam away

J02005 10 19 2000 45 23 45 18Loggerhead alive, injured beak/mouth 1 0 0 55hooked on a single leader with hook in

mouth;swam away quickly and

seemed unharmed

J02005 10 24 2000 46 1 44 3Loggerhead alive, injured beak/mouth 1 0 0 56biopsy sample from RR

flipper;seemed fine as it swam away

J02005 10 24 2000 46 0 44 3Loggerhead alive, injured ingested (throat/esophagus) 0 0 0 61swallowed hook of single

leader;sampled RR flipper;cut leader

inside mouth and released;swam

away fast

J02005 10 24 2000 45 59 44 7Loggerhead alive, injured beak/mouth 1 0 0 41hooked in the mouth on single

leader;turtle missing lower right part of

dorsal shell,but the skin underneath

was healed with no open

wounds;bottom shell not

damaged;might have been hit by boat

in the past;hook easily removed;swam

away fine

J02005 10 31 2000 41 36 51 9Leatherback alive, injured flipper 0 0 1 120hooked in RF flipper; caught on single

leader;leader cut;swam away
311

No/Yes/Unknown

0/1/2

LF=left front RF=right front LR=left

rear RR=right rear

trip m d y lat deg lat min lon deg lon min species condition hook location

hook

removed entangled

line left

(ft)

CL

(cm) additional comments

J02005 10 31 2000 41 38 51 14Leatherback alive, injured flipper 0 0 3 150very large;foul hooked in the right

shoulder on a single leader;pulled

hard on linet;line cut and it dove under

boat immediately

J02005 10 31 2000 41 39 51 17Leatherback alive, injured flipper 0 0 1 120hooked in bottom of RF flipper on

single leader;line cut and swam away

fine

S01031 11 6 2000 26 46.2 79 53.8Loggerhead alive, injured beak/mouth 0 0 3 80hooked in side of beak; entire hook

visible; leader cut close to animal;

swam away strongly

S01031 11 8 2000 31 54 79 40.1Loggerhead alive, injured flipper 0 0 6 80hooked in LF flipper;leader cut;swam

away strongly

S01031 11 10 2000 31 39.1 79 15.3Leatherback alive, uninjured unknown other 1 0 0 150turtle escapes,pulling out hook;no

gear left on turtle;little apparent

injury;associated with leader but

leader unhooked while pulled towards

the boat;swam away strongly

J02005 11 10 2000 40 47 66 36Leatherback alive, injured head/neck (external) 0 1 1 120foul hooked in the neck and tangled in

a bullet drop; removed all tangled line;

swam away

J02005 11 13 2000 40 49 66 35Leatherback alive, injured unknown other 0 0 1 150unable to confirm id from photos;foul

hooked in LF flipper;swam away

strongly; seemed unharmed

K02003 12 11 2000 40 32 66 59Loggerhead alive, injured beak/mouth 0 0 0 45brought to boat side on hook;line cut

at eye of hook which was in

beak;swam away quickly

S01032 12 13 2000 28 24.3 78 15.1Leatherback alive, injured flipper 0 0 6 160hooked LF flipper;released in good

condition;black
APPENDIX 4

DOCUMENTATION FOR F/PR

REVIEW OF POST HOOKING

MORTALITY
313

APPENDIX 5. DOCUMENTATION FOR F/PR REVIEW OF POST

HOOKING MORTALITY

ATTACHMENT A

Interim Guidelines for Determining Serious Injury of Sea Turtles Taken

Incidentally by the Pelagic Longline Fisheries

The development of guidelines for determining serious and non-serious injuries is

essential because NMFS is mandated to reduce the levels of mortality and serious injury

as mandated by the Endangered Species Act. The pelagic longline fisheries, targeting

swordfish and tuna, have interactions with leatherback and loggerhead sea turtles.

Although there is a low rate of observed mortality, there is a high likelihood of serious

injuries.

Leatherback turtles seldom consume baited hooks, but often become entangled in

the gangions. Fishermen usually attempt to remove all entangled gear, but the large size

and robust nature of the leatherback often make this dangerous and difficult to do.

Loggerhead turtles, on the other hand, usually consume the baited hooks and are either

hooked in the mouth or throat and are usually cut free with some monofiliment leader

attached.

 Criteria for determining serious and non-serious injuries of marine mammals have

been developed (Angliss and Demaster, 1998). However, the criteria for marine

mammals and sea turtles are undoubtedly different and need to be developed. Sea turtles,

unlike marine mammals, are apparently able to sustain considerable injuries and still

survive. Loggerhead turtles are able to keep feeding with multiple hooks imbedded in

their mouths (Argano et al, 1992) and are even able to expel swallowed hooks (Aguilar et

al., 1995). Loggerheads commonly survive severed limbs (Gramentz, 1989).

The injuries commonly observed and recorded by NMFS observers will be

categorized as non-serious, serious, and serious with associated mortality.

I. Non-serious injuries:

1. Entanglement of monofiliment line (mainlines, gangion line, or float line)

where there are no visible injuries (cuts and/or bleeding) and gear is completely removed.

II. Serious injuries meet any the following life threatening criteria:

1. Entanglement of monofiliment line (mainline, gangion line, or float line) could

directly interfere with feeding

2. Entanglement of monofiliment line (mainline, gangion line, or float line) could

interfere with mobility 

3. Entanglement of monofiliment line (mainline, gangion line, or float line)

resulting in substantial wounds (cuts, constriction, bleeding) on any body part.

4. An animal ingests hooks in beak or mouth (visible) could interfere with

feeding.

5. An animal is hooked externally in neck or flippers resulting in wound.
314

III. Serious injuries (with associated mortality) are those animals that:

 1.Animal is hooked inside throat/esophagus hooked (28.9%) (Aguilar et al.,

1995)

 2. Are beak/mouth hooked with substantial line attached (>3 feet loggerheads and

>6 feet leatherbacks) (unknown mortality rate).

The following are commonly observed injuries and suggested injury classification:

NS= non-serious injury, SI= serious injury, SM= serious injury with associated mortality.

unknown mortality rate)

Leatherback turtles:

 Entangled (cut free) NS

Entangled (line trailing>6 feet) SI

Hooked Externally (line trailing>6 feet) SI

Hooked Mouth (line trailing <6 feet) SI

Hooked Mouth (line trailing >6 feet) SM*

Loggerhead (hard-shelled) turtles:

Entangled (cut free) NS

Hooked Externally (fine trailing) SI

Hooked Externally (cut free) SI

Hooked Externally (hook removed) SI

Hooked Beak/mouth (line trailing <3 feet) SI

Hooked Beak/mouth (fine trailing >3 feet) SM*

 Hooked Beak/mouth (cut free) SI

Hooked Beak/mouth (hook removed) SI

Hooked Throat/esophagus (line trailing) SM*

Hooked Throat/esophagus (cut free) SM (28.9%)

Hooked Throat/esophagus (hook removed) SM (28.9%)
315

ATTACHMENT A

References

Aguilar, R., J. Mas, and X. Pastor. 1995. Impact of Spanish swordfish longline fisheries

on the loggerhead sea turtle caretta caretta population in the western Mediterranean.

NOAA-NMFS-SEFSC-Technical Memorandum 361:1-6.

Angliss, R.P. and D. P. DeMaster. 1998. Differentiating serious and non-serious injury of

marine mammals taken incidental to commercial fishing operations-. Report of the

serious injury workshop 1-2 April 1997, Silver Spring, Maryland. NOAA Technical

Memorandum NMFS- OPR- 1 3, 48 p.

Argano, R., R. Basso, M. Cocco, and G. Gerosa. 1992. Novi dati spostamenti di tartaruga

marina comune (Caretta caretta) in Mediterraneo. Bollettino Musel Istitiuti Universitita.

Genova 56- 57:137-163.

Gramentz, D. 1989. Marine turtles in the Central Mediterranean Sea. Centro 1:41-56.
316

ATTACHMENT B

Developing Interim Guidelines for Determining Serious Injury of Sea Turtles Taken

Incidentally by the Pelagic Longline Fisheries

Sea turtles are listed as either endangered or threatened under the U.S.

Endangered Species Act (ESA). The National Marine Fisheries Service (NMFS) and U.S.

Fish and Wildlife Service (USFWS) share jurisdiction for sea turtles under the ESA.

Section 7 of the ESA requires federal agencies to consult with either NMFS or USFWS

when their actions are likely to affect listed sea turtles. In the case of domestic pelagic

longline fisheries managed under a federal Fishery Management Plan, the NMFS Office

of Sustainable Fisheries must consult with the NMFS Office of Protected Resources

relative to the effects of the fishery on sea turtles. Sea turtles are incidentally taken as

bycatch in federally-managed pelagic longline fisheries. Observers accompany a small

percentage of pelagic longline trips and record data on sea turtle bycatch, among other

things. Since mid-1999 observers have used the attached observer reporting form to

record the condition of bycaught turtles. Table I provides an example of the comments

recorded by observers on board pelagic longline vessels. NMFS analyzes observer data to

estimate the total lethal and non-lethal take of sea turtles in the fishery. These estimates

are critical to understanding the population-level effects of this bycatch and the estimates

are used to monitor sea turtle bycatch relative to take levels authorized in the Incidental

Take Statement of the Section 7 Biological Opinion, under the ESA. While there is a low

rate of observed mortality (i.e., turtles dead when the longline is hauled in), there is a

high likelihood of serious injuries which may or may not eventually result in the death of

the animal.

 NMFS defined "Serious Injury" for marine mammals as "any injury that will likely result

in mortality" and defined "Injury" as "a wound or other physical harm. Signs of injury to

a marine mammal include, but are not limited to, visible blood flow, loss of or damage to

an appendage or jaw, inability to use one or more appendages, asymmetry in the shape

of the body or body position, laceration, puncture or rupture of eyeball, listless

appearance or inability to defend itself, inability to swim or dive upon release from

fishing gear, or signs of equilibrium imbalance. Any animal that ingest fishing, gear, or

any animal that is released with fishing gear entangling, trailing or perforating any part

of the body will be considered injured regardless of the absence of any wound or other

evidence of an injury." (50CFR §229.2). Requirements of the Marine Mammal Protection

Act (MMPA) resulted in the convening of a workshop to differentiate between serious

and non-serious injuries of marine mammals (Angliss and Demaster, 1998 - enclosed).

The definition of "injury" for marine mammals and sea turtles are not likely to be

identical and, thus, NMFS recognizes the need to review its current methodologies and to

develop sea turtle specific definitions and criteria to determine which interactions

between sea turtles and pelagic longline gear are likely to result in injuries leading to

mortality (serious injuries) and which are not.

The result of sea turtle interactions with pelagic longline gear include entanglement

and/or hooking (external or internal). The at-sea "treatment" that a captured turtle

receives is variable and depends on conditions including, but not necessarily limited to,

federal regulatory requirements, turtle size and species, the presence of an observer, the
317

sea/weather conditions, experience and motivation of the captain and crew, and nature of

the interaction. A general description of the Atlantic pelagic longline fishery and a report

of gear, environment and fishing practice parameters which may influence sea turtle

interactions are enclosed for your information.

For discussion and review purposes the following categories are proposed:

I. Non-serious injuries:

1. Entanglement in monofilament line (mainlines, gangion line, or float line) where

there are no visible injuries (cuts and/or bleeding), the gear is completely removed, and

the turtle swims strongly away from the vessel.

II. Serious injuries that may or may not result in mortality when turtles are released

alive after the interaction:

I . Entanglement in monofilament line (mainline, gangion line, or float line) that

directly or indirectly interferes with mobility such that feeding, breeding or migrations

are impaired.

2. Entanglement of monofilament line (mainline, gangion line, or float line)

resulting in substantial wound(s) (cuts, constriction, bleeding) on any body part.

3. Hooking external to the mouth resulting in substantial wound(s) (cuts,

constriction, bleeding) with or without associated external entanglement and/or trailing

attached line.

4. Ingestion of hook in beak or mouth (visible), with or without associated external

entanglement and/or trailing attached line.

5. Ingestion of hook in the mouth, throat area, esophagus or deeper with or without

associated external entanglement. and/or trailing attached line.

NMFS is seeking comments and input on the effects of these types of interactions on the

health and viability of turtles involved in such interactions. Recommendations on

apportioning mortality based on detail-specific criteria are sought.
318

ATTACHMENT C

John Hoey- Comments on SEC initial draft criteria

Draft criteria for determining serious injury and/or mortality for sea turtle pelagic

longline interactions (October 10, 2000 e-mail draft from Wayne Witzell).

This initial draft reflects the decision rules that were used in the June 20, 2000 biological

opinion, i.e. that almost all sea turtle - longline interactions cause serious injuries. While

only a few were coded as serious injury with associated mortality I think that there are

additional non serious injury conditions that are reasonable and would help encourage

careful handling. Given the limited post-release data available the assumption that "there

is a high likelihood of serious injuries" seems questionable. Given the text references in

the third paragraph to turtle hardiness and resilience, the phrase "high likelihood" should

be replaced by "varying levels of risk depending on the species and type of interaction".

This would seem to be more in line with NMFS Technical Memo - SEFSC-222 which

appeared to emphasize internal wounds.

Despite reference in paragraph 3 to the serious injury workshop on marine mammals and

the undoubtedly different" criteria for serious injury for sea turtles, the categorizations

presented at the bottom of page 1 reflect discussions on marine mammal injuries and

interactions primarily with gillnet gear and pot warps from lobster gear. As I mentioned

at the serious injury workshop and in more recent discussions and written comments,

there are very important gear differences between gillnets and lobster pot warps that must

be acknowledged.

In the marine mammal serious injury discussions, the interaction types that are listed

under item II - ie. Serious Injury with respect to entanglements that interfere with

feeding, mobility and cause substantial wounds - referred specifically to heavy multifilament nylon lines in single strands and multiple strands that wrapped around

appendages with the resulting drag and friction cutting through soft tissue and bone. The

diameter, number of strands, weight in water, and drag associated with these gears is very

different than those same characteristics and others associated with the types of

monofilanient lines used in the U.S. pelagic longline fishery.

The monofilament used by the longline fleet is designed to have negligible resistance and

drag and extremely low weight despite having great strength. In 1998 and 1999 gangion

pound tests were usually > 300 lb. test (only one set with 250 lb. test), whereas mainline

pound tests were usually -e- 600 lb. test. These characteristics must be factored into the

serious injury criteria along with the fact that very few longline observer comments

(based on my partial examination of Atlantic interaction forms) note cutting or tearing,

wounds on appendages, whereas this is frequently noted for marine mammal interactions

with gillnets and lobster warps. I think it is critically important to draw a distinction

between the different weights, pound tests, for the monofilament line that is associated

with turtle interactions. George Balazs included information on monofilament

strangulation for Hawaiian Green turtles on page 130 of the Honolulu lab program review

2000 document. The illustrated entanglement was attributed to recreational shoreline

fishing with 6-lb. test monofilament. I believe there have been similar observations
319

associated with jetty fishing in the Gulf of Mexico and Atlantic. It should be part of the

standard sampling protocol for monofilament samples to be taken for all stranded or

nesting turtles that have attached gear.

As I mentioned at the serious injury workshop and in discussions with SEFSC and PR

turtle scientists, monofilament line has memory (stretch) characteristics, especially for the

pound test used for mainlines (usually > 600 lb. test) and gangions (usually > 300 lb.

test), that make it very difficult to knot or twist and tangle strands so that the knot or

tangle will hold once tension is eliminated from the line. Because of these characteristics

fishermen rely on crimps to connect sections of line, especially the heavier mainline. In

those cases where entangled turtles are released with trailing loops of monofilament that

do not include an attached hook that is impeded in an appendage or shell, it would be

very likely that the gear will simply fall off once line tension is released.

In those cases where an external hooking has occurred or where the hook is in the beak,

jaw, or tongue (externally visible) and the turtle is released with limited line attached, the

size of the turtle and length of attached line should be considered. There are no reports

that I am aware of that specifically identify a line length threshold of I meter for

loggerheads and 2 meters for leatherbacks, nor is rational provided in the draft for these

arbitrary length thresholds. These lengths may be reasonable targets now that the fleet is

required to carry line cutters, but this hasn't been the case in the recent past and it should

be discussed with observers who have experience with conditions aboard vessels

especially freeboard height and hauling practices. Since the 1995 Hawaii workshop

emphasis has been placed on not pulling or putting tension or pressure on the line that is

entangling the turtle. Fishermen therefore chose to leave slightly more line on the turtle

when freeboard was high or weather conditions limited the Captains ability to maneuver

because they thought that was better for the turtle than dragging the turtle closer to the

boat. This would be particularly true for leatherbacks especially when they were active. A

5 meter threshold for leatherbacks would reflect reasonable handling distances aboard US

commercial vessels where an attempt to avoid straining the line and dragging the turtle is

probably being made. Five meters of monofilament would probably weigh less than a

pound or two in the water which would seem to be a negligible drag, on a several

hundred pound leatherback. Some of this concern about a line length threshold relates to

post-classification (after the fact) when NMFS has not provided clear guidance to the

fishermen. The same can be said for classifying all turtles as hooked by ingestion

including those clearly noted as hooked in the mouth when the observer guidance

described in Technical Memo SWFSC - 222 indicated that hooks were considered

ingested if the hook was "past the mouth cavity and in the esophagus".

If all turtles that are released are all categorized similarly as seriously injured whether

they are trailing small lengths of monofilament (< I or 2 meters as drafted) after being

either externally hooked or hooked in the jaw (hook left in), released with only the hook

in the jaw (no trailing gear), and hooked turtles that are completely disentangled with the

hook removed, these criteria will undermine efforts to encourage careful handling

and extra effort to maximize survival. I can't see how this risk averse decision would

be consistent with previous agency actions relative to other fisheries, handling, or

resuscitation guidelines, and the limited post-release data that is available.
320

Post-release mortality studies include Aguilar's study of survival of deeply hooked

turtles from the Spanish Mediterranean fishery which uses very small hooks and baits

and provides the 28.9% mortality rate listed on page 2 of the draft. Information from

tracking studies from the Hawaiian longline fishery need to be reviewed. In the

Honolulu lab program review 2000 document (page 130) it is noted that satellite

transmitters have been deployed on 38 loggerheads, 11 olive ridleys, and 3 green turtles

(a total of 52). "Twenty seven of the deployments have resulted in pelagic trackings

ranging from 0.2 to 8.2 months duration covering distances of 13 - 7,282 km. The

remaining 13 deployments have produced no tracking data, and all of these involved

turtles that were classified as "deeply hooked" (hook lodged in the esophagus and

impossible to remove)." This last sentence seems to be an incomplete thought and the

total of 27 and 13 is 40, so an obvious question remains about the remaining 12 tracks.

The next two sentences in the program review are as follows: "Of the 39 tracked turtles,

22 were deeply hooked and 17 "lightly hooked" (the hook was in the jaw or elsewhere

externally allowing easy removal). There were no significant differences between these

two groups for the duration of transmissions in months or the distance the turtles

traveled." Additional information on these tracking results are critically important. If all

13 of the turtle deployments that produced no tracks were deep hooked what other

condition notes were recorded and are these included in the total of 22 listed as deeply

hooked or in addition to the 22? What was the species breakdown for the lightly and

deeply hooked turtles and for the no track turtles?

If the 13 no tracks are in addition to the 22 deeply hooked then we have 39 tracked turtles

and 13 no track turtles (total 52) with 35 deeply hooked and 17 lightly hooked. If the 13

no tracks only reflect short-term mortality as opposed to transmitter or battery failure or

another co-variate, then 37% of the deeply hooked turtles may have died. The obvious

questions include what the additional condition notes might include and whether the no

track deployments all share a common characteristic (same trip, same month, similar

area, similar size and species, transmitter lot, battery lot, etc.). In any case given the

number of observations in both the Anguilar and Balazs studies it would seem that this

data could justify assigning a mortality rate between 30% and 40% for deeply hooked

turtles. I would assume given similar tracking distances and speeds a much lower

mortality rate (some might argue a negligible rate) would be justified for lightly hooked

turtles. Those turtles that are completely disentangled should not be categorized as

injured unless wounds or trauma are evident.

In light of the preceding I would offer the following alternative categorizations of

interaction types:

1. Not Injured - Turtles that spit hooks and baits while the gear is being retrieved and

entangled turtles where hooks are not involved and where the turtle is released with no

gear attached.

2. Non-serious Injury (lightly hooked). - Disentangled externally hooked turtles

(not in jaw, beak or tongue) released with limited1 gear attached. Also include

turtles hooked in the jaw, beak, or tongue (externally visible) if the hook was

removed for those sizes of turtles that could be brought aboard with dipnets and

there was no other tissue damage or bleeding noted. Externally hooked (not in jaw,
321

beak, tongue, or neck - only carapace, flippers or tail) large turtles released trailing

gear longer than the limited1 gear thresholds but less than 5 meters in length.

3. Serious injury - level 1 (deeply hooked but limited gear). - Hook lodged in the

esophagus and impossible to remove with the turtle released with limited1 gear attached

and observer notes indicating active and reasonable condition. Externally hooked turtles

released with limited1 gear attached and with non-critical tissue damage or limited

bleeding noted, including turtles hooked in the jaw, beak, or tongue (externally visible).

Different mortality ranges should be provided for these two groupings.

4. Serious Injury - level 2 (deeply hooked with excessive gear). -Hook lodged in

the esophagus and impossible to remove with the Turtle released with more than the

limited1 gear attached and/or wounds noted to the eyes or neck. If an attached buoy was

left trailing that would be a serious injury level 2 along with any turtles where the

observer notes reference struggling or weak condition or a visible serious wound more

extensive than a hook puncture.

Assigning rough quantitative ranges for mortality rates to the preceding categories will

require a thorough review of the condition notes associated with the Honolulu tracking

studies and any other information that has been developed over the last few years. This

should be a topic for more extensive discussions including a range of people with greater

experience than I have on events at-sea as well as vets and other biologists. It would seem

reasonable however for the mortality rates for serious injury - level I deeply hooked

turtles and serious injury - level 2 deeply hooked turtles to be different and preliminary

range estimates might be reasonably established once the tracking study results are more

thoroughly reviewed. I would also obviously have a 5th category for dead turtles.

1Refers to line distances of <1 meter for loggerheads and <2 meters for

leatherbacks.
322

COMMENTS FROM ELLIOT JACOBSEN

Developing Interim Guidelines for Determining Serious Injury of Sea Turtles Taken

Incidentally by the Pelagic Longline Fisheries

 Comments

 1. It is clear from the Final Report 50EANA7QO063, that not only do the terms "injury,

non-injury, and serious injury" need to be defined, but that the observations and

nomenclature to describe the observations must be standardized. Here are some

recommendations:

a. Serious Injury: having a negative effect on turtle survivorship or negative

effect on the animal's contribution to the population.

b. Definition of injury for marine mammal and sea turtle should be the same. The

causes may be different. Injury: damage inflicted to the body by an external force (from

Doriand's Illustrated Medical Dictionary).

c. While by process of elimination, a non-serious injury would be an injury that

is not defined as a serious injury, still this needs definition.

d. A definition of "foul-hooking" needs to be included in any document.

2. Major problem is that we can't determine the extent of injury without establishing

criteria for a healthy marine turtle. A group has been formed at the University of Florida

to establish the "gold standard" for sea turtle health assessment. This will take several

years to define. So when an attempt is made to try and categorize or establish criteria for

injury, both serious and non-serious, realize that we are limited in our ability to

stringently categorize animals. Clearly an animal that is moribund and appears to be near

death because of obvious massive injury is easy to categorize. The difficulty is with those

animals that appear to have minimal external damage but may have significant internal

damage or are septic as a result of the injury. As all of us in medicine know, trying to get

a handle on these cases is extremely challenging. So everyone needs to know what the

limitations are. To come up with a more meaningful way of categorizing these animals,

ultimately turtles with certain types of injuries need to be followed through time using

satellite monitoring, This will be the only way to get a scientifically based handle on,

outcome of injured animals. Categories of injuries can be established and criteria then

developed to allow some type of categorization. Hopefully this will be an outcome of

your proposed meeting.

3. We believe that any animal that is released with an intact attached hook, is at risk,

especially if line is still attached. The more line, the more risk of being snagged

underwater and drowning. The level of risk of drowning is dependent on the size and

robustness of the turtle, as well as the area hooked. Of the 30 stranded turtles evaluated in

a study done by us, at least 10% had evidence of fishing line injury severe enough to

explain the cause of death. One had swallowed line, resulting in imbrication of the

intestinal tract. One had a hook lodged in the larynx, associated with necratizing

laryngitis. One had an abscess ventral to the tongue, which could have resulted from a
323

fish look lodging there. I think the abscess impacted on the turtle's ability and desire to

eat. It should be assumed that if a turtle is entangled, that a hook could be internalized.

The only way to dismiss this would be to radiograph these turtles. Even if a hook was

found externally, that would not preclude an internal hook. A turtle with a swallowed

hook could be in grave danger.

4. Questions to be answered:

a. How long does it take for hooks to rust out?

b. How stable is the monofilament line relative to disintegrating in salt water?

c. Is it possible to salvage any of the turtles for rehab, to conduct a parallel study

with radiotransmitters?

d. In the report, there was a suggestion that some turtles could be entangled

multiple times in longlines. What is the likelihood of this happening?

e. How toxic are light-sticks if they are swallowed? Are they ever swallowed?

 5. There was no mention in the "Description of Longline Fishery" paper of what is used

to weigh down the lines in the water. I assume that no toxic metals (for e.g., lead) are

used.
324

FROM Edward R. Gaw, HI-LINER FISHING GEAR AND TACKLE, INC.

November 16, 2000

UNITED STATES DEPARTMENT OF COMMERCE

NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION

National Marine Fisheries Service

 Attn: Office of Protected Resources

Room 13630,

 Silver Spring, MD 20910

Dear Ms. Conant,

Thank you for the opportunity to participate in your initial solicitation of input

concerning sea turtle- pelagic long-line interactions. HI-LINER Fishing Gear is the

largest US exporter of pelagic monofilament long-line materials to the world pelagic

swordfish/tuna long-line fleets. We maintain several offices in many coastal nations to

provide local inventory, product support and technical expertise. Currently, we remain

the key supplier to a majority of pelagic long-line vessels fishing from Spain, Portugal,

South Africa, Brazil, Uruguay, Mexico, Chile, Australia - to name a few. It is the purpose

of this letter to establish the position and standing of -HI-LINER among the world-wide

pelagic long-line fleets, principally those plying the North/South Atlantic oceans,

HI-LINER has maintained a long history of product introduction, development and

extension. The evolution of this style of fishing equipment has not been limited to the

US. Acceptance of this material by other more traditional fishing nations has produced

advancements and improvements in both equipment and technique. HI-LINER's

emphasis on the operational success of individual international fishing vessels has left us

uniquely qualified to comment on long-line gear principles, dynamics and continued

product evolution.

However, your solicitation specifically requested input concerning injuries and their

relative short/long term implications. It remains my strong belief that our subjective

contribution to this phase of your investigation would contribute little to the attainment of

the true goal of your discussions, Minimization/Avoidance of Sea Turtle//Pelagic Longline Harmful Interactions. I would formally request that HI-LINER be consulted directly

prior to any discussion of gear modifications, operational gear parameters and dynamics

relative to sea turtle interactions. Combinations of traditional foreign fishing techniques

with modern monofilament pelagic long-line gear has proved the flexibility and

malleability of this style of fishing.

At your convenience, your review would be greatly appreciated. Please advise your

requirements. Thank you for your time and considerations.

Regards,

Edward R. Gaw

HI-LINER FISHING GEAR, Inc.
325

UNIVERSITY OF CHARLESTON

Grice Marine Laboratory

205 Fort Johnson

 Charleston, South Carolina 29412

 November 18, 2000

Telephone: (843) 406-4000

Facsimile: (843) 406-4001

E-mail: owensd@cofc.edu

 Dr. Donald R Knowles

Director

 Office of Protected Species

NOAA/ NWS

 Silver Spring, MD 20910

 Dear Dr. Knowles,

I have received the packet of information on the concerned interactions between

sea turtles and longline fishing gear. The following comments are my initial reactions to

the materials sent in the packet as well as my general sense of the importance of this

particular conservation issue. Other than the information you sent, I do not have a good

knowledge of this particularly fishery.

Observations:

1. Generally speaking, sea turtles are robust animals and can recover eventually from

superficial external injuries such as would occur from a hook that is removed.

2. Physiologically, it is my impression that the leatherbacks are not as resilient hardy as

the hard shelled turtles. This is suggested because of softer epidermal tissue, softer heads

and beaks, heavier body mass and generally softer bodied food sources. Thus such

actions as hooking, lifting from the water, and ingestion of hooks and lines may have

more damaging and long lasting impacts on an individual leatherback.

3. Ingestion of a hook and line (depending on size) is likely to have long term impact on

survivability of any sea turtle. We see lots of "floaters" in South Carolina. These turtles

generally have a peritoneal infection which is causing gas to accumulate in the body

cavity. Eventually these animals weaken and die unless treated. While I do not know this

for a fact, hooks could be an initial cause of this problem. My concern is that ingested

hooks may provide a long term irritant and source or bacterial entry. In addition, if the

hook lodges in heart or lung tissue, or results in occlusion of the gut, the turtle may die

directly for the event.

4. Leaving several yards of monofilament line hanging from the mouth is another source

of potential problem. The line can be fouled and cause drag, swallowed causing an

occlusion of the gut or wrapped around a flipper or caught on another object. Feeding
326

will be impaired to some degree depending on several variables.

Recommendations:

 1. A physiological study of naturally hooked animals could address some of these

concerns. Variables to be evaluated are movement of hooks once the line is cut, impact

on feeding ability, changes in stress hormone and reproductive hormone levels and

susceptibility to local or internal infections. In an aquarium, under proper medical

supervision animals could safely studied. If and when they appeared to be suffering or

taking a serious turn for the worse, surgical and antibiotic treatment could be applied to

insure survival and eventual release.

2. Several veterinarians have experience in removing hooks. Their observations and

results could be instructive in this regard.

3. Whenever possible, the entire line and any portion of the hook which can be seen

should be cut out prior to release of the animal.

4. Additional observer work would seem to be important in zones 5, 6 and 7 and possibly

2.

I believe this fishery interaction is a serious problem for sea turtles.

Sincerely,

 David Wm. Owens

 Professor and Director

 Graduate Program in Marine Biology
327

FROM MOLLY LUTCAVAGE, PHD, SENIOR SCIENTIST, NEW ENGLAND

AQUARIUM

Donald R. Knowles

Director, Protected Species

National Marine Fisheries Service

Silver Spring, MD 20910

24 November, 2000

 Dear Dr. Knowles,

Thank you for the opportunity to submit comments on the materials that your

office forwarded re. effects of interactions between longline fishing gear and sea turtles.

NMFS is doing the right thing by developing criteria describing long line gear

interactions that are specific to sea turtles. Although marine mammals and sea turtles

share the distinction of being air-breathing vertebrates, they have very different behaviors

and susceptibilities or responses to human interactions. Since we don't have all of the

answers regarding gear interactions and sea turtles, it will be productive to have a suite of

descriptions that accurately characterizes a sea turtle's condition, and disposition of gear

left on the animal. Only then will all parties have the necessary information to proceed

with mitigation that will limit or eliminate harmful interactions, and reduce burdens for

fishermen if and when it is appropriate to do so. Specific comments follow below:

I. " Non-serious injuries" This category is contradictory and misleading. A "non-serious

injuries" cannot be equal to "no visible injuries". If the animal is not injured, the

observation should clearly state it as such.

1. Suggested alternatives to non-serious injuries that would describe animals that have

run into gear but that have no visible injuries and are not suspected to have had them:

Gear Interaction 1, resolved (trailing or entangling gear has been removed)

Gear Interaction 2, gear not completely removed.

 2. "Visible injury, minor (superficial)

 Any visible injuries such as cuts, minor lacerations- that are not likely to jeopardize the

health or impair the movements or behavior of the turtle. This type of injury would be

expected to spontaneously heal/resolve.

II. Serious Injuries The five types of interactions could all be construed as serious.

However, there are still some grey areas. For example, Entanglement in monofilament

line. That interferes with mobility... such that feeding, breeding or migrations are

impaired." Does this mean that the turtle is released with the monofilament, or that it was

impossible to free it of binding gear? If yes- then of course, this is serious injury. But if

the animal were freed of the mono and then showed signs of strength and normal

swimming/behavior, would the designation of serious injury still hold true? [I hope that

we all are working to making this situation go away. If still alive, all badly entangled
328

animals need to be freed of gear. I need to know/understand whether there are cases

where a longliner crew would be unable to free the turtle? If the turtle is attached via float

line to rest of gear, doesn't the boat always have some line to the animal that can be

retrieved?]

 Regarding 4. Ingestion of hook in beak or mouth... does this mean that the observer can

see the hook? There are cases where sea turtles have hooks in the keratinized tomium, but

because it's not in the soft tissue, there may be little or no impairment, and the hooks

eventually get dislodged. This is different than cases where the hook is in the soft tissue,

where it is likely to be pushed further into the tissue.

Possible alternatives could be

Gear Interaction- Hooking

 1. Visible, external, no obvious injury [no mortality expected]

 2. Visible, external, injured [injuries serious, mortality could result)

3. Internal/Gut hooked; serious injury suspected or likely. [mortality could result]

From Table 1 1999 NOAA Fisheries Sea Sampling Program observers can

obviously provide descriptive information that can be used to make an assessment of a

turtle's status, especially in regard to serious vs. non serious injury, and whether a turtle is

injured at all. There's plenty of room for improvement. For example, "hooked in mouth"-

does this mean in the tomium, or in the soft tissue? Another one "swam off readily,

although seem tired." My impression is that with explicit training, observers could

provide unambiguous information. Photographs are also useful as supporting

information.

 The information provided by the Hoey report was extremely helpful. His analysis

provides a good place to start to examine environmental relationships between sea turtles

and longline gear, and where they are most likely to converge. However, we need more

details, as temperature ranges were quite broad. We had this same problem in trying to

find relationships between leatherbacks and real-time ocean frontal conditions, using

limited aerial survey data from right whale and other surveys. For example, depending on

geographic area, leatherbacks were found in SST's ranging from 10 -230 C, even though

the average SST from right whale survey databases was 160 C (Distribution of

Leatherback Turtles in relation to the Environment, Cooperative Agreement

#40GENF400929, report to NMFS SEFSC, M. Lutcavage). Most of our observations

came from inshore surveys, and are not particularly helpful in identifying offshore habits.

I understand that the NMFS SEFSC recently funded a study by Morreale to examine

SST's and location of longline sets that had interactions with sea turtles. It would be very

helpful if these results were made available for review. It would also be important to see

Scott Eckert's results of diving habits and travel patterns of leatherbacks that he's tracked

with satellite transmitters in the Atlantic and elsewhere, particularly if this study were

funded by NWS and if a technical report were available for distribution.

I was dismayed to see NMFS incorrectly use a report prepared by Greenpeace

(submitted to the Sea Turtle conference but not subjected to peer review), in the recent

Biological Opinion (Jun 30,2000). Page 35 states "Perhaps a better way of looking at the

data is to apply the 29% mortality estimate provided by Aguilar (1995) to the average
329

annual estimated take of 715 animals (Yeung et al., in prep) which indicates that an

average of 207 animals annually either die or are seriously injured by pelagic longlines in

the U.S. fleet." There is no way of knowing whether the Yeung et al. data is convincing,

because the reader is unable to see it. The Aguilar et al. paper provides useful (although

very general) information on turtles taken in the Spanish longline fishery, but is

extremely flawed as a scientific paper on post release mortality or survivorship. The data

shown in their Table 1, which suggests that " 20-30% of sea turtles may die after having

been captured by a longline" is based on turtle survivorship of animals kept in "large

aquaculture pools with the aim of estimating the mortality rate of the individuals released

with hooks still in their bodies ..." The authors of this study did not conduct necropsies to

establish cause of death, which is an absolute requirement, nor did they conduct control

experiments that would establish whether the captured turtles had a lower survivorship

than animals not subject to capture but also held in the tanks. Anyone that has raised sea

turtles in captivity knows that they are subject to infections, disease, and other problems

that arise from culture. Without addressing all of these concerns, this study cannot be

used to establish survivorship or post release mortality. It would not have passed peer

review, and NWS needs to be honest about using it as "best available science" when it is

clearly does not satisfy sufficient scientific standards for establishing cause of death.

Similarly, the reference to Balaz unpublished data (page 60) on a "44% mortality

estimate observed by Balaz (person. comm) needs to come forward for evaluation. A

good scientist cannot simply accept an unsubstantiated estimate for this important issue.

Without a report to evaluate, there is no credibility.

The report prepared by Augliss and DeMaster was comprehensive, accurate, and

very well done. It clearly sets the agenda for sea turtle/longline interactions, and it should

serve as a model and guide for discussion and process for establishing distinct sea turtle

criteria. For example (page 4)" Participants stressed that a thorough necropsy is necessary

to determine the cause of death of large cetaceans and the degree to which an

entanglement may have contributed to the mortality... (and as a footnote.... was stressed

for all marine mammals in general)." The section "Collecting data on injuries" was also

extremely important and clear on what needs to be done- the same holds for sea turtles:

"Workshop participants identified several actions that would improve the data that

observers provide on incidental injuries, such as 1) improve the training for recording

interactions with marine mammals, 2) include marine mammal scientists in the

debriefing... 3) encourage observers to provide more detail ...". All of these points are

relevant to sea turtle and long line interactions.

Although I've listed some comments above, I look forward to further discussion at

our upcoming meeting. Thanks again for the opportunity to weigh in on this issue.

Sincerely,

Molly Lutcavage, Ph.D.

Senior Scientist, ERL
330

United States Department of the Interior

U.S. GEOLOGICAL SURVEY

National Wildlife Health Center

Honolulu Field Station

300 Ala Moana Blvd, P. 0. Box 50167

Honolulu, Hawaii 96350

Phone: 808 541-3445, Fax 808 543-3472

E-mail: thierry_work@usgs.gov

November 20, 2000

FAX

TO: Therese Conant

FROM: Thierry Work

Total Pages : 3

Dear Ms. Conant

Thank you for the opportunity to review the material on long line and marine turtle

mortalities. In an attempt to make this issue more tractable, consider the following simple

model:

Line is set-->turtle is attracted to line-->turtle gets hooked-->turtle dies or survives

Line setting:

What factors are conducive to turtle being hooked and how could these be prevented?

Contract report 50WANA700063 outlines some of these including depth of line, time of

set, temperature, use of light sticks, area of set, date of set.

Attraction:

What is it exactly that attracts turtles to bait? Are there certain bait types that would be

equally attractive to fish but less so to turtles? Could artificial baits be developed that are

repellent to turtles but not target fish? Could sonic devices be placed around lines that

repel turtles? This would call for research on olfactory and visual cues that attract turtles

to bait.

Hooking:

According to the contract report, this appears to be one area where more information

could be gathered.

Once an animal is hooked or entangled in the line, how severe is the injury? The NOAA-
331

NMFS-OPR-13 goes some way into defining that for marine mammals. Defining injury

based on hook placement alone in marine reptiles may be misleading. For example,

lightly hooked turtles (hook on beak only, no visible trauma) may drown from forced

submergence. On the other hand, we saw turtles with traumatic amputations of the

forelimb from fishing line that survive quite well. Also, some turtles considered deeply

hooked and tracked by satellite have been shown to survive many months. Finally, an

animal may be hooked in the flipper (survivable injury)but released with several feet of

leader thus posing potentially lethal risk of the leader wrapping around limbs or neck and

causing strangulation or limb amputation. Perhaps consider standardizing criteria to

define an animal as uninjured, moderately or severely injured using something like the

following criteria.

Uninjured-Animal vigorous, breathing is unremarkable, hook on beak only (easily

removed with no visible trauma) and no evidence of external trauma from line or hook.

Moderately injured- Visible trauma from hook on beak, flipper or shell. Visible trauma

from line around flipper (e.g. abrasion or cutting into flipper). Animal vigorous, breathing

is unremarkable.

Severely injured- Hook in soft tissue of mouth (tongue, soft palate), or deep into

esophagus. Leader wound tightly around limb with a partial avulsion or amputation.

Alternatively, no visible injuries but animal weak.

Documenting: Following data would probably be helpfu11 to standardize reporting.

Items (*) are those used to decide whether animal is uninjured, moderately, or severely

injured. Items(*,**) may be useful for long term prognostication.

-Hook number and type

-Date and time of set

-Water temperature

 -Type of light stick used (color, make)

-Hook location*

 -Photo of hook set in turtle or of line-induced injury*

-Length of turtle

 -Hooked removed (Y/N)**

 -Animal (vigorous, weak, dead)*

 -If hook not removed, length of lead left on hook.**

 Any dead animals should be stored frozen and returned to a laboratory for complete

post-mortem exam. Alternatively, observer puts animal aside and performs a necropsy

taking appropriate samples in formalin and frozen once catch is finished (how realistic

this is depends on conditions on the boat). Perhaps NMFS needs to dedicate observers to

do this task only (documenting extent of injuries and doing necropsies).

Other avenues of pursuit: Given that hooks are set in 24 hour periods, are there materials

that can be used to make hooks that will have similar tensile strength as steel but will

degrade or dissolve in, say 7-10 days? For example, some darts used to immobilize

animals have a needle with a barb made of a material that dissolves once it contacts body

fluids thus causing less injury when the dart is removed. Th key would be to find a would
332

be to find a material that dissolve, just more slowly (>24 h) allowing desirable fish to be

caught.

Turtle dies or survives.

 Efforts should be made to satellite tag animals in uninjured, moderate, and severely

injured category to evaluate long-term outcomes. Perhaps this could readily be done in

fisheries that consistently catch large numbers of turtles. A model animal could be

something not critically endangered like the loggerhead.

I hope this is of some use.

Sincerely

Thierry M. Work

Wildlife Disease Specialist
333

FROM JOSEPH P. FLANAGAN DVM, HOUSTON ZOOLOGICAL GARDENS

4 Dec 2000

Donald R. Knowles

Director

 Office of Protected Resources

 Dear Dr. Knowles,

I have been working with sea turtles for approximately 16 years through the National

Marine Fisheries Service Galveston Laboratory. During that time I have seen a number of

sea turtles (mostly Kemps Ridleys) which have been caught on hook and line in the

recreational fisheries here on the upper Texas coast. These turtles by and large, have

ingested hooks and are presented within a day of capture.

Presentation has varied with size of the turtle, type of hook (size, shape, material),

presence or absence of a leader, and quantity of line present. My approach to treatment

has varied with the actual location of the hooking, At presentation, the hook may be

present in the oral cavity, any point in the esophagus, or in the stomach. The damage

done by the hook will vary with the point in the body that is hooked, the depth of hook

penetration, and the length of time the hook has been present. I am never presented with

animals that have had hooks for more than a few days.

In general, with a simple hook, the deeper (farther into the esophagus or stomach) the

animal is hooked, the greater the chance of damage or potential damage. important

exceptions to this are animals that are hooked in the oral cavity with the point of the hook

penetrating into the orbit or globe of the eye, or animals that are hooked into a major

blood vessel. Hooks that penetrate through the gut wall can cause variable damage,

depending on what area or which organ the hook impacts. I have observed hooks that

have punctured the major vessels near the heart, resulting in nearly immediate death of

the animal. The point of a hook may cause a localized infection at the point of

penetration. This infection could remain quiescent, and ultimately resolve without long

term harm to the animal, or could result in a generalized infection and death. It is possible

that a hook without a significant length of attached line can pass through the digestive

tract without harming the turtle. I cannot guess at what percentage of cases this may

occur.

Hooks anywhere in the gastro-intestinal system that trail fishing line can lead to placation

of the intestines and potential peritonitis (coelomitis) with a linear foreign body. I

consider any length of trailing line to be a significant risk to the health of a turtle as the

line passes into the intestinal tract. Long lengths of line trailing from the oral cavity can

entangle the turtles neck or appendages and result in physical harm to the animal. Loss of

a flipper may reduce the animals feeding efficiency, its ability to evade predators, or

impact its ability to reproduce.

Animals hooked in locations other than the gastro-intestinal system have a lower risk of

adverse health effects due to the hooking incident. Hooks penetrating skin or superficial
334

muscle groups are likely to establish a localized infection, but are likely to slough with

infected tissue. The turtle will heal albeit with a defect where it was hooked. If hooked in

or near a joint, the injury will be more severe. Penetration of a joint may impact the

animal's mobility and is more likely to result in systemic infection.

Hooked turtles can suffer from harm caused indirectly as a result of their capture.

Animals that are hooked and fight the hook may over-exert themselves, exhausting

muscle energy sources and causing a severe metabolic acidosis. These animals may

appear normal may fight with great force when handled, but may not have the ability to

recover if returned to the sea in an exhausted condition. The longer an animal fights, or

the greater the intensity of the fight, the more likely it will have problems recovering

from the hooking incident.

If an animal is hooked and is unable to surface, it will obviously drown within a

relatively short period of tome. The time will depend on the length of time since the

animal last surfaced, the water temperature, the size of the turtles and the amount of

struggling the animal does on the line.

 Turtle interactions with hooks are traumatic incidents. Although some individuals may

survive relatively unharmed, the vast majority will suffer significant injury and potential

mortality as a result of being hooked.

 If you have any further questions please contact me directly. I apologize that this

response is tardy, but I was away when the package of information arrived.

Sincerely,

Joseph P. Flanagan DVM

Senior Veterinarian

Houston Zoological Gardens

1513 North Macgregor

Houston, TX 77030

houzoovet@juno.com
335

Robert A. Morris, MS, DVM

E. Alan Zane, DVM

Thomas Chelebecek, MS, DVM

MAKAI ANIMAL CLINIC

420 Uluniu Street

Kailua, Hawaii 96734

Phone: 808 262-9621

Fax: 808 262-0658

makaianimalclinic.com

November 24, 2000

Mr. Donald R. Knowles, Director

Office of Protected Resources

National Marine Fisheries Service

Silver Spring, MD 20910

Dear Mr. Knowles:

In response to your request on sea turtles and fishing gear, I offer the following

observations as a contract veterinarian for sea turtles for the National Marine Fisheries in

Honolulu.

1. Some hooks remain unchanged for months in the intestinal tract of

turtles with no evidence of dissolving (followed with X-rays).

2. Turtles have been seen with ingested hooks and are apparently healthy.

On the other hand, hooks that perforate the G.I. Tract can cause death.

3. Hooked turtles trailing monofilament line can cause serious problems

with line wrapped around the flipper, resulting in tissue and bone necrosis.

We have done numerous flipper amputations because of this problem.

Ingestion of the monofilament line can also cause serious problems to the

intestinal tract.

The most important aspect for the survival of hooked turtles is removal of the hook, and

if that is not possible, cut the trailing line as short as possible. Any hooked turtle with

trailing mono line is in serious trouble.

If you require additional information, let me know.

Sincerely,

Robert A. Morris, MS, DVM
APPENDIX 5

OUTPUT FROM GLM WEEK/SQUARE

ANALYSIS FROM LOGBOOK AND

OBSERVER DATA (J. CRAMER,

PERSONAL COMMUNICATION)1

 

1

 Jean Cramer, National Marine Fisheries Service, SEFSC, Miami, Fla. Personal Communication (E-Mail) to Karyl

Brewster-Geisz, National Marine Fisheries Service, ST, Silver Spring, Md., August 28, 2000.
337

APPENDIX 6. OUTPUT FROM GLM WEEK/SQUARE ANALYSIS FROM

LOGBOOK AND OBSERVER. The observer data were not adequate for LSMEAN

calculattion so paramater estimates are included. Justification of any specific week/square

closures based on these analyses is not recommended. Also included are summaries of catch and

effort by week and square.

observer data - GLM estimates - GLM could not calculate LSMEANS

week square estmate T for HO: Pr > |T| Std Err

5 4448 5 B 2.43 0.1356 2.056875

3 4444 4 B 3.61 0.0689 1.108042

2 4446 2.666727 B 1.92 0.1955 1.392376

4 4444 2 B 1.59 0.2522 1.255585

4 4448 2 B 0.99 0.425 2.012003

1 4644 1.666727 B 1.35 0.309 1.232779

1 4840 1.666727 B 0.83 0.4935 2.006322

2 4644 1.414617 B 1.21 0.3496 1.168261

3 4644 1.052996 B 0.98 0.4314 1.077162

3 4248 1 B 0.41 0.724 2.462898

6 4246 1 B 0.41 0.7214 2.437285

7 4448 1 B 0.5 0.6676 2.006051

3 4252 0.666727 B 0.33 0.7712 2.006322

3 4642 0.666727 B 0.34 0.7693 1.988218

1 4842 0.148777 B 0.15 0.8961 1.007371

1 4446 0 B 0 1 1.920636

1 5042 0 B 0 1 1.716277

1 5044 0 B 0 1 1.464651

2 4444 0 B 0 1 1.716277

2 4842 0 B 0 1 1.716277

2 4844 0 B 0 1 1.808528

2 5044 0 B 0 1 0.936151

2 5046 0 B 0 1 1.528656

3 4838 0 B 0 1 1.344445

3 5244 0 B 0 1 2.489428

4 4446 0 B 0 1 2.463896

4 4842 0 B 0 1 1.219153

5 4060 0 B 0 1 1.716277

5 4444 0 B 0 1 1.638742

5 4646 0 B 0 1 1.638742

6 4252 0 B 0 1 0.944764

6 4448 0 B 0 1 2.24065

7 4252 0 B . . .

8 4448 0 B . . .

2 4452 -12 B -4.32 0.0496 2.776546

2 4454 -12 B -3.86 0.061 3.108006

3 4250 -12 B -3.92 0.0593 3.061154

4 4252 -12 B -4.14 0.0538 2.901391

4 4452 -12 B -3.79 0.0631 3.165595
338

observer by week and square data

year week square turtles hooks swordfish tuna mako swordfish blue

kept sharks dead disc sharks

1992 1 4446 0 700 19 2 2 3 24

1992 1 4842 0 2900 90 41 1 7 52

1992 1 5042 0 900 34 10 0 3 13

1992 1 5044 0 1300 24 25 0 1 11

1992 2 4444 0 900 50 0 1 7 2

1992 2 4644 0 900 46 0 1 8 85

1992 2 4842 0 900 45 2 0 1 59

1992 2 4844 0 800 11 0 0 4 50

1992 2 5044 0 4400 92 167 0 1 28

1992 2 5046 0 1175 20 23 1 0 9

1992 3 4444 4 2650 120 0 3 37 40

1992 3 4644 2 1800 64 2 10 22 29

1992 3 4838 0 1600 10 4 0 2 133

1992 3 5244 0 400 1 8 0 1 6

1992 4 4444 2 1900 42 0 3 6 35

1992 4 4842 0 2050 26 4 4 5 68

1992 5 4060 0 900 5 13 4 6 54

1992 5 4444 0 1000 13 0 0 0 14

1992 5 4646 0 1000 2 0 0 0 52

1992 6 4252 0 4270 22 65 6 5 56

1992 7 4252 0 6800 37 204 4 13 47

1993 1 4644 1 7677 252 51 3 7 365

1993 1 4840 1 833 26 16 3 2 30

1993 1 4842 0 833 24 36 4 3 20

1993 2 4446 2 3234 58 9 9 3 140

1993 2 4644 1 5050 83 6 6 11 144

1993 3 4252 0 833 0 0 0 0 99

1993 3 4642 0 855 9 3 0 0 25

1993 3 4644 0 4413 99 47 0 6 136

1994 3 4248 1 977 10 5 3 5 74

1994 4 4446 0 975 12 10 0 3 37

1994 4 4448 2 6184 103 9 2 13 380

1994 5 4448 5 4172 41 17 12 15 622

1994 6 4246 1 1031 6 2 3 9 45

1994 6 4448 0 1733 27 16 0 7 148

1994 7 4448 1 6601 29 109 0 13 504

1994 8 4448 0 638 0 6 0 1 145

1995 2 4452 0 2491 37 42 2 27 63

1995 2 4454 0 810 2 14 2 9 83

1995 3 4248 13 3328 28 7 8 16 230

1995 3 4250 0 900 5 4 0 4 40

1995 4 4252 0 1420 6 0 0 1 114

1995 4 4452 0 720 6 0 0 0 47
339

pelagic logbook

GLM

Pelagic Logbook by week/square

information

year week square turtles hooks swordfish tuna mako

rank week square LSMEAN Std Err p < |T| kept sharks

1 1 4248 38.04656 3.476512 0.0001 1992 1 4250 0 475 4 1 1

2 4 4444 13.70773 2.109026 0.0001 1992 1 4452 0 1275 25 1 0

3 1 4448 11.94983 3.432202 0.0006 1992 1 4646 0 900 17 2 1

4 1 4444 9.167189 4.229116 0.0314 1992 1 4840 0 600 12 0 2

5 1 4246 6.591974 5.89828 0.2651 1992 1 4842 0 19885 715 93 0

6 3 4448 6.546262 2.159462 0.0028 1992 1 4844 0 300 46 8 0

7 2 4248 5.966448 2.294713 0.01 1992 1 5042 0 2950 181 34 0

8 3 4248 5.742755 2.574909 0.0269 1992 1 5044 0 5600 203 77 0

9 4 4446 4.334416 2.122479 0.0425 1992 2 4250 0 1713 28 3 1

10 1 4644 4.097727 1.727501 0.0187 1992 2 4444 0 1800 99 0 0

1 4446 4.08015 1.815838 0.0258 1992 2 4446 4 1857 94 2 2

2 4446 4.071254 1.619608 0.0128 1992 2 4448 0 650 45 0 0

2 4448 3.632665 2.038123 0.0763 1992 2 4644 0 2350 91 0 1

5 4250 3.575505 4.163747 0.3916 1992 2 4840 0 600 7 0 0

3 4644 3.021021 2.034206 0.1391 1992 2 4842 0 9965 265 14 1

1 4642 2.793801 2.061334 0.1769 1992 2 4844 0 4475 108 3 0

5 4252 2.722604 2.851401 0.3409 1992 2 5042 0 1390 28 4 0

3 4446 2.625707 2.150802 0.2236 1992 2 5044 0 11600 287 191 0

4 4448 2.579225 2.071762 0.2147 1992 2 5046 0 2650 51 50 0

2 4646 2.555904 4.472763 0.5684 1992 2 5244 0 700 1 0 0

5 4448 2.266134 2.030568 0.2658 1992 3 4442 0 525 15 0 0

4 4254 2.18361 12.46683 0.8611 1992 3 4444 0 6715 230 1 13

6 4242 2.18361 11.75824 0.8529 1992 3 4446 1 9173 209 3 12

8 4050 2.18361 12.87327 0.8655 1992 3 4452 1 800 10 0 1

8 4254 2.18361 5.676411 0.7009 1992 3 4640 0 600 33 0 0

9 4050 2.18361 16.6006 0.8955 1992 3 4642 0 1650 60 0 8

9 4252 2.18361 4.837753 0.6522 1992 3 4644 0 4750 145 1 9

6 4446 2.050717 2.549333 0.4221 1992 3 4646 0 1200 38 1 0

5 4248 1.988738 2.183946 0.3636 1992 3 4838 0 800 2 0 0

2 4644 1.970357 2.193176 0.3701 1992 3 4840 0 650 25 0 0

6 4250 1.86782 4.413338 0.6726 1992 3 4842 0 1200 38 0 0

5 4246 1.863365 3.619301 0.6073 1992 3 5042 0 1740 47 5 0

9 4254 1.855847 3.787676 0.6247 1992 4 4248 0 4475 65 9 1

6 4246 1.843074 7.14484 0.7967 1992 4 4250 0 700 8 3 0

8 4052 1.826013 8.193979 0.8239 1992 4 4444 2 5675 147 0 1

4 4248 1.408435 2.676202 0.5993 1992 4 4446 0 4357 86 10 3

4 4642 1.350205 6.401193 0.8332 1992 4 4452 0 800 5 4 0

1 4048 1.336023 11.75383 0.9096 1992 4 4644 0 1200 23 0 2

3 4246 1.336023 9.360587 0.8867 1992 4 4646 0 546 14 1 0

8 4248 1.336023 7.20122 0.853 1992 4 4842 0 3300 60 5 2

4 4644 1.328913 3.60866 0.7131 1992 5 4060 0 920 5 8 1

8 4252 1.28315 4.193874 0.76 1992 5 4248 1 5750 107 3 16

3 4444 1.250512 2.9182 0.6687 1992 5 4252 0 800 9 15 1

4 4246 1.03153 4.191992 0.8059 1992 5 4446 2 6602 134 0 2

1 4844 0.991732 20.32625 0.9611 1992 5 4642 0 600 5 0 1

1 5042 0.991732 6.563621 0.8801 1992 5 4644 0 650 7 1 0

1 5044 0.991732 4.822412 0.8373 1992 5 4646 0 800 2 0 0

2 4840 0.991732 14.39344 0.9451 1992 6 3646 0 600 0 0 1

2 4844 0.991732 5.366931 0.8536 1992 6 4246 0 700 22 0 1

2 5042 0.991732 9.49212 0.9169 1992 6 4248 0 1000 20 2 3

2 5044 0.991732 3.440961 0.7735 1992 6 4250 0 700 10 30 2

2 5046 0.991732 6.915489 0.8861 1992 6 4252 0 13269 92 215 10

2 5244 0.991732 13.33209 0.9408 1992 6 4446 7 5200 138 2 4

3 4442 0.991732 15.38173 0.9487 1992 6 4448 1 600 12 0 1

3 4838 0.991732 12.47697 0.9367 1992 6 4646 0 600 13 1 3

3 4840 0.991732 13.83207 0.9429 1992 7 3646 0 1200 0 0 0

3 5042 0.991732 8.497955 0.9072 1992 7 4050 0 700 2 17 0

5 4060 0.991732 11.64148 0.9322 1992 7 4250 0 2100 23 57 2

5 4644 0.991732 13.83207 0.9429 1992 7 4252 0 12180 86 288 5

5 4646 0.991732 12.47697 0.9367 1992 8 3652 0 550 8 0 0

6 3646 0.991732 14.39344 0.9451 1992 8 4252 0 1300 9 6 2

6 4646 0.991732 14.39344 0.9451 1992 9 3652 0 1400 22 2 1

7 3646 0.991732 10.20679 0.9227 1993 1 4248 0 700 27 0 0

7 4050 0.991732 13.33209 0.9408 1993 1 4446 3 10103 403 53 12

8 3652 0.991732 15.02987 0.9475 1993 1 4642 1 17363 400 82 1
340

9 3652 0.991732 9.458607 0.9166 19931 46440 17240 701 1439

6 4448 0.987413 3.116216 0.7517 19931 46460 900 4000

7 4248 0.917757 7.241926 0.8993 19931 48420 1600 43 392

1 4452 0.90495 4.700001 0.8475 19932 42480 3500 7322

5 4446 0.901864 1.828119 0.6223 19932 42500 800 1620

6 4248 0.856986 3.165948 0.7869 19932 44440 900 1000

1 4842 0.842021 1.934716 0.6639 19932 44460 14221 343 83 19

1 4646 0.838079 5.002197 0.8671 19932 44480 3332 98 315

7 4254 0.819685 5.739307 0.8866 19932 46420 1755 3910

7 4250 0.760192 3.622224 0.834 19932 46441 14715 387 23 11

3 4640 0.55606 8.347488 0.947 19933 42480 3700 11179

6 4252 0.529315 2.116877 0.8028 19933 42520 800000

5 4642 0.514853 7.533691 0.9456 19933 44460 3900 9894

3 4646 0.508295 3.212907 0.8745 19933 44480 4200 12467

1 4442 0.452922 11.18048 0.9677 19933 46440 7813 179 750

5 4444 0.415727 10.63696 0.9689 19934 42480 1592 5443

2 4444 0.388213 3.151279 0.9021 19934 42500 1650 15 130

1 4254 0.336023 13.22502 0.9798 19934 42520 1002 1670

1 4426 0.336023 15.74838 0.983 19934 42540 800921

2 4450 0.336023 9.063057 0.9705 19934 44440 1700 70 111

3 4254 0.336023 12.46267 0.9785 19934 44460 4600 206 104

4 4440 0.336023 12.46267 0.9785 19934 44480 3900 10182

5 4048 0.336023 12.52512 0.9786 19934 46420 1500 2980

5 4442 0.336023 12.09258 0.9779 19934 46440 4725 106 415

6 4048 0.336023 9.146854 0.9707 19934 46460 1625 54 181

6 4050 0.336023 19.92372 0.9866 19935 42482 6280 220 22 13

7 4048 0.336023 6.220446 0.957 19935 42505 3400 35 330

7 4446 0.336023 12.46267 0.9785 19935 42524 8876 175 426

7 4448 0.336023 3.131405 0.9147 19935 44460 10650 243 52 11

8 4048 0.336023 12.22195 0.9781 19935 44480 3800 140 345

8 4448 0.336023 7.980808 0.9665 19936 42420 900800

9 3624 0.336023 13.3187 0.9799 19936 42460 1750 3600

4 4442 0.101257 8.871961 0.9909 19936 42480 8400 25672

7 4252 0.074759 1.77076 0.9664 19936 42500 4250 7310

4 4646 -0.003579 4.303882 0.9993 19936 42520 5689 90 120

1 4840 -0.013541 4.846092 0.9978 19936 44460 900 3200

3 4642 -0.079081 4.10617 0.9847 19937 42480 750703

2 4642 -0.106997 3.078485 0.9723 19937 42500 1500 3115

2 4842 -0.132768 2.379078 0.9556 19937 42540 10008 101

4 4842 -0.206355 4.132621 0.9602 19938 40500 750 1410

3 4452 -0.256974 3.579916 0.9428 19938 40520 1500 5820

4 4252 -0.780433 3.126416 0.8031 19938 42520 3950 86 433

3 4842 -0.895688 3.559009 0.8016 19938 42540 3950 57 552

6 4444 -0.936157 3.601823 0.7952 19939 40500 450400

1 4250 -0.989438 3.367858 0.7692 19939 42520 5500 43 771

1 4252 -1.044962 3.66705 0.776 19939 42540 8217 39 1978

2 4242 -1.136635 12.47794 0.9275 19941 40481 900 1400

4 4058 -1.136635 8.336204 0.8917 19941 42468 2816 3505

4 4256 -1.136635 12.47794 0.9275 19941 42482 2412725

4 4258 -1.136635 11.17144 0.9191 19941 42501 1716 1011

7 4452 -1.136635 8.901383 0.8985 19941 42540 710511

7 4642 -1.136635 10.89459 0.917 19941 44260 5000 1220

7 4842 -1.136635 15.33897 0.941 19941 44440 1110 1505

8 4452 -1.136635 8.358926 0.892 19941 44461 4983 12807

9 4452 -1.136635 11.77002 0.9232 19941 44480 1620601

2 4252 -1.199624 4.442209 0.7874 19941 46420 900811

2 4452 -1.259475 3.64673 0.7302 19941 46445 10655 173 113

1 4640 -1.382719 8.853452 0.8761 19941 46460 900 2300

2 4454 -1.382719 7.284791 0.8497 19941 48423 6675 121 443

3 4252 -1.418203 5.120237 0.7821 19942 42484 8268 91 16 23

2 4250 -1.457348 3.370972 0.666 19942 42520 700 1281

5 4452 -1.579442 7.101895 0.8242 19942 44442 1760 3030

4 4250 -1.599746 4.050886 0.6933 19942 44468 16700 401 83 26

6 4254 -1.621699 6.626616 0.8069 19942 44480 2020 57 331

4 4452 -1.953195 4.533314 0.6671 19942 44500 1520 3700

6 4256 -2.009572 4.115112 0.6259 19942 44520 720500

5 4254 -2.118888 5.714885 0.7112 19942 46421 3276 75 236

6 5242 -2.382719 7.93314 0.7642 19942 46441 6776 153 411

7 5242 -2.382719 7.93314 0.7642 19942 46461 2252 4110

3 4250 -2.697149 4.980931 0.5888 19942 48421 1437 31 110

5 4454 -2.754489 10.17243 0.7868 19943 42461 1424 3037

4 4454 -2.896713 5.910216 0.6246 19943 42482 1697 4083
341

3 4450 -3.022163 18.84143 0.8727 19943 42540 800645

4 4450 -3.022163 12.91007 0.8152 19943 44441 5512 113 15 16

4 4648 -3.022163 12.91007 0.8152 19943 44461 5990 214 274

5 4256 -3.022163 10.24921 0.7684 19943 4448 10 18251 510 135 18

19943 46400 1188 28 163

19943 46420 3030 37 128

19943 46440 1692 1610

19944 42460 3960 82 139

19944 42480 3400 366 20

19944 42520 2362 16 293

19944 44400 800 2038

19944 44421 7929 11 10

19944 44444 8784 216 25 32

19944 44465 11987 278 28 24

19944 44483 24781 535 84 39

19944 46422 750 1543

19944 46440 2160 51 176

19945 40480 792700

19945 42481 7089 69 18 10

19945 42501 3121 5261

19945 44420 850800

19945 44440 350200

19945 44460 10750 228 362

19945 44486 9763 115 51 16

19945 46420 1600 1600

19946 40480 1492 2210

19946 40500 312100

19946 42480 800 1420

19946 42500 800301

19946 42520 2700 1541

19946 42540 800742

19946 42560 1056100

19946 44440 1400 1910

19946 44460 900600

19946 44481 8512 84 1336

19947 40480 3264 28 276

19947 42480 1632 1371

19947 42500 6180 48 506

19947 42522 8248 41 365

19947 42540 2820 2590

19947 44460 8008 100

19947 44480 13768 82 3566

19948 40480 832070

19948 40520 360370

19948 42481 2422 32 214

19948 42520 1056400

19948 44480 19668 131

19949 36240 700.60

19951 42500 3400 48 503

19951 42520 6600 74 1838

19951 44440 700 1500

19951 44466 12890 278 10 19

19951 44484 2460 4604

19951 44520 1700 51 22 12

19951 46401 1600 3771

19951 46424 2580 6300

19951 46449 6490 17562

19952 4248 11 5862 17566

19952 42500 8014 73 1148

19952 42521 5871 65 1393

19952 44441 2588 8040

19952 44462 5842 15532

19952 44489 7848 15735

19952 44521 9321 176 1119

19952 44541 2380 31 517

19952 46440 900 2700

19953 4248 24 5899 1048 14

19953 42500 2610 15 120

19953 42520 3221 36 100

19953 44440 500910

19953 44522 8710 158 204

19953 46449 12164 34941
342

19953 46464 1350 4730

19954 42520 1620510

19954 44520 5485 32 163

19954 44540 720920

19954 46463 700 4220

19955 42520 3332151

19955 42540 1050100

19955 44480 3000623

19955 44520 882100

19955 44540 504011

19956 42520 56107 925

19956 42540 2058373

19956 42560 66385 753

19956 52420 20005 250

19957 42521 18456 35 2637

19957 52420 2000440

19961 44485 1670 4204

19961 46420 8251 183 3063

19961 4644 20 2552 38 142

19961 48401 4900 80 1160

19961 48420 9050 203 2180

19962 42420 800 20 300

19962 42500 960400

19962 44441 4875 11049

19962 44465 5835 6417

19962 46420 7029 110 3553

19962 46440 1458 18 110

19962 46460 900600

19962 48420 13265 107 2350

19963 42480 800302

19963 42520 800 1300

19963 44460 1910 1501

19963 44520 800 1100

19963 46420 2860 39 710

19963 46440 4950 61 190

19963 46460 4450 65 252

19963 48420 9400 157 1840

19964 40580 18108 450

19964 42463 3311 341 15

19964 42520 8454 80 346

19964 42560 800230

19964 42580 1000000

19964 44420 790621

19964 4444 34 9700 153 22 21

19964 4446 10 4490 9636

19964 44480 792310

19964 46420 800420

19964 46460 4000 102 286

19964 48420 4250 32 1030

19965 42463 10395 1194 31

19965 42520 1352 1216

19965 44460 11062 141 228

19965 44480 5980 98 217

19965 44520 1600 12 140

19966 44440 8884 110 1066

19966 44461 12304 163 806

19966 44480 800 1030

19967 42520 3160 1490

19967 44520 1584 1320

19967 46420 1052110

19967 48420 528100

19968 42520 900 11 250

19968 44520 18008 270

19969 42540 900142

19969 44520 900200

19971 42520 2024610

19971 44460 4569 9339

19971 44480 840 1916

19971 44520 3276 22 277

19976 42500 700301

19976 42520 700020

19981 42460 800 3010
343

19981 42480 800 2791

19981 42520 1000 17 100

19981 44420 1000 2500

19981 4444 12 5444 15824

19981 44466 6473 234 158

19981 44485 1100 6260

19981 4642 12 3200 139 1101

19981 46441 6000 296 314

19981 46460 2330 9982

19982 42480 525 1100

19982 44441 950 45 120

19982 44462 6671 26701

19982 44485 10511 34721

19982 46440 1850 75 120

19982 46464 3200 157 146

19983 44442 2564 9804

19983 44465 7941 29925

19983 44480 1350 8200

19983 46440 950 1660

19983 46461 5550 17042

19984 42480 600 2900

19984 44448 4393 17901

19984 44462 4190 12002

19984 44481 1200 4700

19984 46440 1700 6850

19985 42520 600 1551

19985 44440 750 1700

19985 44461 2150 35 160

19985 44482 8515 295 255

19986 42520 1600 39 281

19986 44460 1600 4830

19986 44480 3500 104 530

19987 42520 2400 54 362

19991 4248 61 7090 29439

19991 42502 5940 1262 10

19991 4448 40 2907 11805

19991 46441 3000 197 335

19991 48420 1000 3521

19992 4248 11 6998 25705

19992 44462 1582 34 112

19992 44483 8031 23816

19992 46422 1650 5881

19993 42480 7894 268 145

19993 42500 2525 11832

19993 44482 5631 193 102

19993 44500 350 1600

19994 42485 8518 251 378

19994 42500 5664 125 623

19994 44480 2306 36 221

19994 44500 750 2160

19994 44540 2950 59 321

19994 46480 750 2000

19995 42484 9075 418 227

19995 42500 8005 183

19995 42520 1000 1800

19995 42541 2864 4092

19995 42560 1198 1650

19995 44480 1270 3930

19995 44540 700 10 133

19996 42480 2800 10081