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photo by R. Andrews	Thermal biology of leatherback sea turtles The leatherback turtle (Dermochelys coriacea) (<=1000 kg) is the largest extant species of sea turtle and has the widest geographic range of any reptile, with migratory routes that take them from nesting beaches in the tropics to foraging grounds at temperate and sub-polar latitudes. Leatherback turtles maintain internal body temperature (Tb) several degrees higher than ambient water temperatures (Tw) while freely swimming in tropical seas (Southwood et al., 2005), and instantaneous recordings of cloacal temperature from a turtle captured off the coast of Canada show that a thermal gradient of up to 18°C may be established in cold water (Frair et al., 1976). The ability to elevate Tb above Tw is thought to be an important aspect of the leatherback turtles’ biology that allows this species to venture into temperate latitudes during long distance foraging migrations, but field data on Tb and Tw are still needed to confirm the magnitude of the thermal gradient for freely swimming turtles at high latitudes and the effects of foraging behavior, activity levels, and diving patterns on Tb. Physiological attributes other than maintenance of a thermal gradient may also contribute to the leatherback turtle’s ability to exploit cold water habitats. The biochemical adjustments made by leatherbacks during long-distance oceanic migrations to temperate latitudes warrant further study.
	related papers:
	- Southwood, A.L., Andrews, R.D., Paladino, F.V., and Jones, D.R. 2005. Effects of diving and swimming behaviour on body temperatures of leatherback sea turtles in tropical seas. Physiol. Biochem. Zool. 78(2): 285-297 - *PBZ 2005* PDF file - Southwood, A.L., Andrews, R.D., Lutcavage, M.E., Paladino, F.V., West, N.H., George, R. H., and Jones, D.R. 1999. Heart rates and diving behaviour of leatherback sea turtles in the Eastern Pacific Ocean. J. Exp. Biol. 202:1115-1125 - JEB 1999 PDF file


photo by J.Y. Swimmer	*Fisheries interactions with endangered species* Incidental capture of endangered sea turtles in fishing gear is a cause of concern for fisheries managers, fishers, and environmentalists alike. Sea turtles may sustain serious injuries while entangled or hooked in fishing gear and may drown if they are not discovered and released in time. The behavioral and physiological consequences for sea turtles released alive from fishing gear may be substantial, but very little research has been directed at assessing the health status of sea turtles following a fisheries encounter. When combined with post-release behavior data, measurements of biochemical and hormonal parameters indicative of exhaustive exercise, disruption of respiratory and metabolic processes, cellular and tissue damage, and induction of a stress response may prove to be a useful tool in evaluating mortality of sea turtles due to fisheries interactions. Poster presentation on Biochemical Predictors of Mortality (Symposium on the Biology and Conservation of Sea Turtles, Island of Crete, Greece, 2006)
photo by R. Andrews	*Seasonal bioenergetics* Changes in biotic and abiotic factors have profound effects on the energetics of reptiles. Sea turtles inhabit tropical to temperate latitudes and experience fluctuations in environmental conditions on a seasonal basis and during long-distance migrations. Alterations in ambient temperature directly impact biochemical reaction rates and metabolic processes of sea turtles, and changes in activity patterns related to ecological factors such as food availability and predator abundance may also contribute to seasonal differences in the physiology and behavior of these marine reptiles. The metabolic and behavioral responses of sea turtles to seasonal changes in environmental conditions vary greatly depending on species, geographic location, and local factors. I use a combination of field and laboratory techniques to investigate seasonal differences in dive patterns, cardiovascular variables, metabolic biochemistry, and overall metabolism of sea turtles, and I strive to integrate data collected at different levels of biological organization to better understand the organismal response to a changing environment.
	related papers: - Jones, D.R., Southwood, A.L., Andrews, R.D. 2004. Energetics of Leatherback Sea Turtles. In Experimental Approaches to Conservation Biology. Gordon, M.S. and S. M. Bartol (eds). Berkeley. University of California Press, Ltd. pp 66-82 - Southwood, A.L., Darveau, C.A., Jones, D.R. 2003. Metabolic and cardiovascular adjustments of juvenile green turtles to seasonal changes in temperature and photoperiod. J. Exp. Biol. 206: 4521-4531 - JEB 2003 PDF file - Southwood, A.L., Reina, R.D., Jones, V.S., and Jones, D.R. 2003. Seasonal diving patterns and body temperatures of juvenile green turtles at Heron Island, Australia. Can. J. Zool. 81(6): 1014-1024 - CJZ 2003 PDF file -Southwood, A.L., Reina, R.D., Jones, V.S., Speakman, J.R., and Jones, D.R. 2006. Seasonal metabolism of juvenile green turtles at Heron Island, Australia. Can. J. Zool. 84 (3): 125-135 - CJZ 2006 PDF file

photo by L.A. Harden	*Thermal ecology and habitat utilization of diamondback terrapins* The diamondback terrapin (Malaclemys terrapin) is the only estuarine species of turtle, and generally inhabits the shallow brackish waters of coastal marshes and creeks. Diamondback terrapin populations have decreased throughout their range over the past couple of decades, and this reptile is currently listed as a “Species of Concern” in North Carolina. Factors contributing to population decline are habitat loss, road and boat mortality, nest predation, and mortality due to incidental bycatch in fishing gear. The North Carolina Blue Crab Fishery Management Plan (NC Division of Marine Fisheries, 2004) states that research to determine the distribution of diamondback terrapins, particularly areas of overlap with blue crab habitat, is necessary in order to devise proper regulations and management strategies to minimize interactions between terrapins and crab pots (Blue Crab FMP, Section 10.3.5.4), thereby reducing fisheries-related mortality for terrapins. We have initiated surveys to assess relative abundance and distribution of diamondback terrapins in waters utilized by commercial and/or recreational crab fisheries in the marshes of southeastern North Carolina. We are also using radiotelemetry and micro-dataloggers to assess home range, diving and basking patterns, seasonal movements, and habitat utilization. Tissue samples collected from terrapins are used to determine thermal dependence of metabolic enzymes and seasonal changes in metabolic biochemistry.
photo by L.A. Harden