PacificPacific--Atlantic Sea Turtle Atlantic Sea Turtle AssessmentAssessment

(PASTA) (PASTA) Working Group MeetingWorking Group Meeting

Report for PFRP meeting November 14Report for PFRP meeting November 14--16, 2005 16, 2005 Honolulu, HawaiiHonolulu, Hawaii

Molly LutcavageMolly LutcavageSelina HeppellSelina Heppell

Abigail McCarthyAbigail McCarthy

PASTAPASTA

PIs: Molly Lutcavage, Selina HeppellPIs: Molly Lutcavage, Selina Heppell

Steering committee:Steering committee:David Kirby, Rebecca Lewison David Kirby, Rebecca Lewison

Yonat Swimmer, Melissa Snover (NOAA Yonat Swimmer, Melissa Snover (NOAA PIFSC)PIFSC)

Abby McCarthy (grad student) Abby McCarthy (grad student)

PASTA participantsPASTA participantsMolly LutcavageMolly Lutcavage BiologyBiology University of New HampshireUniversity of New HampshireSelina HeppellSelina Heppell Life historyLife history Oregon State UniversityOregon State UniversityDavid KirbyDavid Kirby ModelingModeling Oceanic Fisheries Oceanic Fisheries ProgrammeProgramme, Secretariat of the , Secretariat of the

Pacific CommunityPacific CommunityRebecca LewisonRebecca Lewison BycatchBycatch San Diego State UniversitySan Diego State UniversityMelissa SnoverMelissa Snover ModelerModeler Pacific Islands Fisheries Science CenterPacific Islands Fisheries Science CenterTomo EguchiTomo Eguchi GeneticsGenetics SW Fisheries Science CenterSW Fisheries Science CenterMartin Hall Martin Hall Fisheries Fisheries InterInter--American Tropical Tuna CommissionAmerican Tropical Tuna CommissionJeanette Wyneken Jeanette Wyneken PhysiologyPhysiology Florida Atlantic UniversityFlorida Atlantic UniversitySimon Hoyle Simon Hoyle Fisheries Fisheries InterInter--American Tropical Tuna CommissionAmerican Tropical Tuna CommissionJeffrey Seminoff Jeffrey Seminoff Coastal fisheriesCoastal fisheries SW Fisheries Science CenterSW Fisheries Science CenterFrancisco Chavez Francisco Chavez OceanographyOceanography Monterey Bay Aquarium Research InstituteMonterey Bay Aquarium Research InstituteFrancois Royer Francois Royer ModelingModeling University of New HampshireUniversity of New HampshireVince SabaVince Saba BiologyBiology Virginia Institute of Marine ScienceVirginia Institute of Marine ScienceKate MansfieldKate Mansfield Coastal fisheriesCoastal fisheries Virginia Institute of Marine ScienceVirginia Institute of Marine ScienceYoshiYoshi MatsuzawaMatsuzawa BiologyBiology Sea Turtle Association of JapanSea Turtle Association of JapanYonat SwimmerYonat Swimmer Coastal fisheriesCoastal fisheries Pacific Islands Fisheries Science CenterPacific Islands Fisheries Science CenterJay VaughanJay Vaughan BiologyBiology Oregon State UniversityOregon State UniversityAbby McCarthyAbby McCarthy OceanographyOceanography Oregon State UniversityOregon State University

PurposePurpose

To assemble a unique group of modelers, To assemble a unique group of modelers, oceanographers, fisheries scientists and oceanographers, fisheries scientists and sea turtle biologists to develop a sea turtle biologists to develop a framework for comparative analysis of framework for comparative analysis of loggerhead and leatherback sea turtle loggerhead and leatherback sea turtle populations in the north Atlantic and North populations in the north Atlantic and North Pacific. Pacific.

New people, new ideas, new synthesis!New people, new ideas, new synthesis!

Goals of the projectGoals of the project

Develop hypotheses to determine what Develop hypotheses to determine what drives sea turtle population dynamics and drives sea turtle population dynamics and the relative role of human impacts on both the relative role of human impacts on both ocean basin and species levelsocean basin and species levelsDesign assessment tools to test those Design assessment tools to test those hypotheseshypothesesProvide guidance for research, Provide guidance for research, management and mitigationmanagement and mitigation

Why?Why?

Arguably, we should simply be promoting Arguably, we should simply be promoting every possible means to reduce human every possible means to reduce human impacts on declining populations of sea impacts on declining populations of sea turtles, BUTturtles, BUT

Elimination of impacts is not possible, nor Elimination of impacts is not possible, nor likely necessarylikely necessaryLimited time, money for research and Limited time, money for research and monitoringmonitoringNeed to know “how much is enough”Need to know “how much is enough”

Long time series: leatherbacks, PacificLong time series: leatherbacks, PacificMexico (Pacific)

y = 8961.2e-0.279x

R2 = 0.7292

y = 1487.5e-0.2552x

R2 = 0.6179

0100020003000400050006000

1984

1986

1988

1990

1992

1994

1996

1998

Mexiquillo

Chacahua

Malaysia

y = 9297.9e-0.1511x

R2 = 0.922

02000400060008000

100001200014000

1968

1971

1974

1977

1980

1983

1986

1989

1992

1995

1998

Leatherback females Playa Grande, Costa Rica

0200400600800

1000120014001600

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

French Guiana y = 13625e0.0359x

R2 = 0.1509

0

10000

20000

30000

40000

50000

60000

70000

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

Nes

ting

fem

ales

St. Croix y = 17.79e0.0869x

R2 = 0.7087

020406080

100120140160180200

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

Florida y = 87.691e0.1376x

R2 = 0.8793

0100200300400500600700800900

1000

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

Leatherbacks in the Atlantic/ CaribbeanLeatherbacks in the Atlantic/ Caribbean

Objectives of this meetingObjectives of this meetingIdentify the likely impacts of human and natural stressors Identify the likely impacts of human and natural stressors on sea turtle abundance, vital rates, distribution and size on sea turtle abundance, vital rates, distribution and size structure. structure.

SYNTHESIS over broad spatial and temporal scalesSYNTHESIS over broad spatial and temporal scales

Compare those impacts and expected population Compare those impacts and expected population dynamics for loggerhead and leatherback turtles in the dynamics for loggerhead and leatherback turtles in the Pacific and AtlanticPacific and AtlanticDevelop testable hypotheses for identifying the drivers of Develop testable hypotheses for identifying the drivers of population changepopulation change

Take advantage of differences in life history, management Take advantage of differences in life history, management efforts, population trends and oceanographic conditions to efforts, population trends and oceanographic conditions to eliminate some alternativeseliminate some alternatives

Identify assessment tools and data gaps required to test Identify assessment tools and data gaps required to test hypotheseshypotheses

Species lifeSpecies life--history differenceshistory differences

Primary habitat is lifePrimary habitat is life--stage specificstage specificAge at maturity: 25Age at maturity: 25--30 30 yearsyearsSmaller body size= Smaller body size= susceptibility to cold susceptibility to cold shock, smaller niche shock, smaller niche sizesizeSlower early growth Slower early growth raterate

Primary habitat is Primary habitat is pelagicpelagicAge at maturity:15Age at maturity:15--20 20 yrsyrsLarge body size= Large body size= greater physiological greater physiological tolerance, larger niche tolerance, larger niche sizesizeFast early growth rateFast early growth rate

http://tofino.ex.ac.uk/euroturtler.htm

Loggerhead (Loggerhead (CarettaCaretta carettacaretta)) Leatherback (Leatherback (DermochelysDermochelys coriaceacoriacea))

STRESSORSSTRESSORSTo nesting beaches:To nesting beaches:

Egg/female Egg/female harvestharvestCoastal Coastal development, development, coastal human coastal human population growthpopulation growthNest predation by Nest predation by native & native & introduced introduced predatorspredatorsCatastrophic Catastrophic natural events, natural events, e.g. hurricanes

To pelagic habitat:To pelagic habitat:

LargeLarge--scale shifts in scale shifts in current/ wind current/ wind patterns, patterns, temperature that temperature that may affect forage may affect forage qualityqualityMarine debris Marine debris aggregations, both aggregations, both direct and indirectdirect and indirectFishing, shifting Fishing, shifting gear types and gear types and location of effortlocation of effort

To coastal habitat:To coastal habitat:

Fishing: gillnet, Fishing: gillnet, trawl, trawl, longlinelonglineEntanglement Entanglement Boat strikesBoat strikesMarine debris Marine debris

e.g. hurricanes

PacificLoggerhead

AtlanticLoggerhead

PacificLeatherback

AtlanticLeatherback

Climate change(Pelagic foraging areas)

Fisheries - CoastalBeach impacts(Egg & Adult harvest,development)

FC

Fisheries - Pelagic

B

FP

C

Climate change(Pelagic foraging areas)

Fisheries - CoastalBeach impacts(Egg & Adult harvest,development)

FC

PacificLoggerhead

AtlanticLoggerhead

Fisheries - Pelagic

B

FP

C

PacificLeatherback

AtlanticLeatherback

AtlanticLoggerhead

PacificLoggerhead

PacificLeatherback

AtlanticLeatherback

Juvenile growth rates, distribution

Subadult, adult survival

Cohort strength, Nester distribution FC

Juvenile survival rates

B

FP

C

AtlanticLoggerhead

PacificLoggerhead

PacificLeatherback

AtlanticLeatherback

Juvenile growth rates, distributionRemigration interval

Adult female survival

Cohort strength, Nester distribution,Adult female survival

FC

Subadult, adult survival rates

B

FP

C

Pac log Atl log Pac LB Atl LBage at maturity 20 30 15 10female hatchlings per year 35 52.5 48 66population trend 0.95 1 0.82 1.03adult survival 0.85 0.9 0.75 0.9

0.0

0.2

0.4

0.6

0.8

1.0

Pac log Atl log Pac LB Atl LB

Ela

stic

ity v

alue

(rel

ativ

e se

nsiti

vity

of

dete

rmin

istic

gro

wth

rate

to a

cha

nge

in

stag

e-sp

ecifi

c su

rviv

al ra

te)

adultjuvenilefertility

Pacific BasinPacific Basin••Higher density of pelagic hooks (4.4 hooks/ kmHigher density of pelagic hooks (4.4 hooks/ km22), more ), more hooks total (718 million) but lower CPUE of turtleshooks total (718 million) but lower CPUE of turtles••Higher concentration of fishing near nesting beachesHigher concentration of fishing near nesting beaches••Less Less bycatchbycatch management/ monitoringmanagement/ monitoring••Larger basin, longer migration lengthsLarger basin, longer migration lengths••More variation in nesting beach productivityMore variation in nesting beach productivity••Lower adult female recapture rateLower adult female recapture rate••More nesting beach development for both loggerheads More nesting beach development for both loggerheads and leatherbacksand leatherbacks••Greater climate change impacts, which may lead toGreater climate change impacts, which may lead to--> >

••Higher variability in forage availabilityHigher variability in forage availability••Longer reLonger re--migration interval for leatherbacksmigration interval for leatherbacks

Fisheries in AtlanticFisheries in AtlanticAtlantic BasinAtlantic Basin••Lower density of pelagic hooks than Pacific Lower density of pelagic hooks than Pacific (3.4 hooks/ km2)(3.4 hooks/ km2), fewer hooks (, fewer hooks (316 million 316 million hookshooks), but higher CPUE of turtles), but higher CPUE of turtles••More More bycatchbycatch management and monitoring management and monitoring than Pacificthan Pacific••More nests for both species and higher More nests for both species and higher number of eggs per nest than in Pacificnumber of eggs per nest than in Pacific••Larger female body size for both speciesLarger female body size for both species••More variable migration patterns for More variable migration patterns for leatherbacksleatherbacks••More reproduction per season (more nests) More reproduction per season (more nests) for leatherbacksfor leatherbacks••Better nesting beach data for both speciesBetter nesting beach data for both species

OnOn--going work going work -- TurtlesTurtlesMap nesting beach trends over time, both for long time Map nesting beach trends over time, both for long time scales and seasonal scales and seasonal Map tracking data for both species in both basins, begin Map tracking data for both species in both basins, begin to address questions of foraging areas/ migration routes/ to address questions of foraging areas/ migration routes/ hot spots on a large scale. How have “hot spots” hot spots on a large scale. How have “hot spots” changed over long timechanged over long time--scales?scales?Investigate age and sex structure of different stocks, Investigate age and sex structure of different stocks, build agebuild age--structured population models to address structured population models to address differences between Pacific and Atlantic differences between Pacific and Atlantic IBMsIBMs for both species in both basinsfor both species in both basins

Future workFuture work-- HabitatHabitat

Determine location and level of effort of coastal Determine location and level of effort of coastal fisheries, especially subsistence fisheries fisheries, especially subsistence fisheries Create a broadCreate a broad--scale hazard map, including scale hazard map, including threat level of individual hazards (dredging, threat level of individual hazards (dredging, development, trawl fisheries, etc.)development, trawl fisheries, etc.)Create habitat definitions and quality ratings for Create habitat definitions and quality ratings for pelagic habitat, compare quality and quantity of pelagic habitat, compare quality and quantity of habitat in both ocean basins. habitat in both ocean basins.