Rearing Leatherbacks in Captivity: Protocols, Health and Research

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Straight Up, Biology 363 Leatherbacks need you
HELP!!!
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Biology and Conservation of Leatherback Sea
Turtles An Ocean Revolution!
 
 
 
By T. Todd Jones
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Canada
involve
mexico
whale shark
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Leatherback Sea Turtles A Canadian Heritage
 
Range Arctic, Atlantic, Indian, Pacific and
Southern Oceans.
Mass 250 900 kg (550 to 2000
lbs.) Length 132 178 cm (52 to
70 in.)
Only completely oceanic-pelagic sea turtle.
Thermoregulates gigantotherm
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Leatherback Deep Divers

• Dives over 1,000 m for prey items.
• Gelatinovore feeds solely on gelatinous
  zooplankton (i.e. jellyfish and ctenophores).

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Jellyfish Diet Gelatinovore

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Decline of the Pacific Leatherback Critically
Endangered

• Currently 55,000 leatherbacks in Atlantic,
  Indian, and Pacific Oceans.
• lt 5,000 adults in the Pacific Ocean from 182,000
  in the 1980s.

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The impact of Commercial Fisheries

• 34 Adult mortality due to fisheries bycatch.
• Nearly 1,500 deaths a year from fisheries
  long-lines and DGN drift-gill net fisheries.

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Ingested Plastics Lead to Death of Marine Turtles
Start a Sea Change
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Jellyfish vs. plastic bag hard to tell the
difference.
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Greenpeace
In some parts of the Pacific there is 6 times as
much plastic as plankton (www.algalita.org)
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What are we doing to conserve Leatherback Turtles?

• Education Awareness
• Research
• Conservation Management

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Life-History Stages
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Captive Rearing Program at Zoology South Campus
Animal Care

• 20 hatchlings summer 2005 (1 nest).
• Lambert Bay Beach, Tortola, BVI.
• Hatchlings were allowed to crawl down the beach,
  removed 20 hatchlings from a group of gt60.
• We transported hatchlings in coolers with damp
  sand. Hatchlings were moistened periodically.
• Within 36 hours hatchlings were in holding tanks
  at the UBC Animal Care Facility.

Nesting female Lambert Bay, Tortola, BVI.
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History of Leatherback Hatchlings in Captivity
Researchers Year
Age
Deraniyagala 1939 662 days
(N1) Spoczynska 1970 lt 3
weeks Berkenmeier 1971 lt 14
weeks (N7) 1 animal 231 days Phillips
1977 lt 32 weeks (N4) Witham
1977 642 days (N1) Chan
1988 gt 2 weeks
(N10) no update Bels et al. 1988
gt 1200 days (N1) Uchida
???? 137 days (N1) Hendrickson
???? lt 40 weeks (N4)
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Pelagic Lifestyle!

• Leatherbacks do not recognize physical barriers
  (oceanic-pelagic lifestyle).

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Feeding a Gelatinovore!
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What about in the wild? laboratory vs.
environment!
Our captive leatherbacks are matching the
conditioning of stranded or by-catch juvenile
leatherbacks. This relationship gives
increased confidence in the predictive power of
our Growth Function and subsequent physiological
research.
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How long does it take leatherbacks to attain
sexual maturity? captive growth rates and size
at nesting.

• VBGF using captive raised and skeletochronology
  from wild growth studies.
• 12 to 16 years to reach minimum nesting size (135
  cm SCL).
• 18 to 22 years to reach mean nesting size (155 cm
  SCL).

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Intake estimate of a single leatherback
throughout hatching to adult.
Food intake growth rate / food conversions
F1 (dW / dt) / K1
Based on feeding captive leatherbacks squid
gelatin 20.16 0.36 kJ g-1 (DW). 10 times more
energy than jelly fish (Lutcavage and Lutz 1986
Davenport and Balazs 1991 Hsieh et al.
2001). Intake of a single leatherback (hatching
to death) 785 tons of jellyfish Or 157,000 MJ

620 tons of jellyfish
165 tons of jellyfish
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Leatherbacks maintain warm body temperatures
thermoregulators?
Thermal Gradients (TB - TW) The tropics 1.2
4.3 oC (Southwood et al. 2005) Northern
temperate waters 8.2 oC (James and Mrosovsky
2004) 18 oC (Frair et al. 1972)
(Leatherback in the cold waters off California)
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Leatherback thermoregulation models.
Gigantothermy (Paladino et al.
1990) Leatherbacks maintain constant high body
temperatures - large size - low metabolic
rate - peripheral tissues as insulation
Regulation of heat loss by controlling blood
flow and thus thermal conductivity.
(Paladino et al. 1990)
Activity Contribution (Bostrom and Jones
2007) By-product heat from overcoming drag could
be used as a behavioral means to control body
temperature. - assuming thermal conductivity is
minimized Regulation of heat gain by varying
swimming speed.
(Bostrom and Jones 2007)
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Whats missing from models? Physiology!
At a steady state temperature gradient Heat
Loss Heat Gain Heat gain Use of activity
to behaviorally control heat production? Heat
Loss Plastron and Carapace - Control of
thermal conductivity through blood flow?
Flippers - Heat exchangers? (Greer et al. 1973)
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Experimental design and protocol.
24 hours
lt 15 min
Simultaneously Record
1) Heat loss from flipper 2) Heat loss from
plastron 3) Activity 4) Thermal gradient
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Equipment and setup.

• Heat Loss
• Heat Flux Transducers -
• Outputs a voltage that is
• proportional to heat flux.
• Heat Gain
• Force Transducer -
• Measures activity
• Body Temperature
• Thermometer pill -
• Transmits pill temperature to a
• receiver.

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Equipment and setup.
.
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Activity changes with temperature.

• TW drop from 25 to 16 oC
• Activity increased each
• temperature change.
• TW raised from 16 to 25 oC
• Activity decreased each
• temperature change.
• TW 25 oC
• - Low activity

Activity Work Heat Production
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Heat loss rate with varying temperature.

• Flipper
• TW 25 oC
• Animal on average did
• not lose heat to the water.
• TW gt 25 oC
• - Animal dumped heat.

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Heat loss rate with varying temperature.

• Flipper
• TW 25 oC
• Animal on average did not
• lose heat to the water.
• TW gt 25 oC
• - Animal dumped heat.
• Plastron
• Heat was lost at all water
• temperatures.

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Captive leatherbacks maintain a larger thermal
gradient in cold water.

• TW 16 0C
• TB was 2 oC above TW
• TW 31 oC
• - TB was 0.5 oC above TW

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Do leatherbacks control heat loss through their
plastron?

• TW lt 25 oC
• Minimum thermal conductivity
• TW gt 25 oC
• Thermal conductivity increases
• k/L 10
• Estimate k 0.25 W/mK
• L 0.025 m (2.5 cm)

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Summary
In Cold Water (TW lt 25 oC) High Activity Low
heat loss in plastron No heat loss in flipper
Large TB - TW In Hot water (TW gt 25
oC) Low Activity Dumping heat in plastron
Dumping heat in flipper Small TB - TW
Suggests 1) Leatherbacks control their
effective insulation thickness. 2) Control of
heat loss in flippers by heat exchangers and / or
blood flow. 3) Behavioral control of heat
production by variation in activity
rate. Leatherbacks are able to control their
thermal gradient.
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Hungry leatherbacks, jellyfish hangouts and
Fisheries.
Juvenile leatherbacks lt 100 cm SCL are only
capable of thermal gradients of 1 3
C. Confining them to the warmer waters of the
Sub-Tropical and southern Temperate. These
warmers waters are not as nutrient rich nor
abundant in productivity thus we can begin to
predict the location of leatherback juvenile
developmental or nursery habitats. Clash
between leatherbacks searching for food in the
equatorial Pacific and the DGN and Longline
fisheries.

SeaWIFS svs.gsfa.nasa.gov
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www.zoology.ubc.ca/tjones
All about sea turtles www.seaturtle.org What
seafood is sustainable to eat -
www.mbayaq.org/cr/seafoodwatch.asp Leatherbacks
in Canada www.seaturtle.ca All about
leatherbacks www.leatherback.org Gets young
people involved in ocean conservation
www.oceanrevolution.org
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All research approved by UBC Animal Care Committee
Acknowledgements
Sea Turtle Care Volunteers UBC Undergraduates Thea
Sellman Dieta Lund
Katerina Kwon
Ashley Houlihan Amir Shamlou
Caitie Lefroy
Annie Pei
Jatinder Lachar Dana Miller
Angela Stevenson
Andrew Yamada Vojta Prilesky
Rafael Vaisman
Erika Kume Oliver Claque
Kristina Sorenson Brian Woo

Veterinarian Assistance Chris Harvey-Clark
Robert George Tamara Godbey
UBC Mechanical Workshop Bruce Gillespie
Vince Grant
UBC Animal Care Center Art Vanderhorst
Sam Gopaul
CITES BVI Canada
Funding NMFS SWFSC PIFSC NSERC Discovery
Grant to DRJ UBC Zoology Animal Care
BVI Government
Salt water supply Vancouver Aquarium MSC
Photos by Michael Carey turtlephotographer_at_yaho
o.com
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Get Involved! Become an Ocean Revolutionary
TODAYAnd start a SEA CHANGE
Please help protect us!!!
Photo Martin Dee