Spatiotemporal Movement Patterns of Hawksbill Sea Turtles (Eretmochelys imbricata) in an Extreme Environment The Arabian Gulf as a Living Laboratory for Investigating Organismal Response to Climate Change


Meeting Abstract

49-4  Saturday, Jan. 5 11:15 – 11:30  Spatiotemporal Movement Patterns of Hawksbill Sea Turtles (Eretmochelys imbricata) in an Extreme Environment: The Arabian Gulf as a Living Laboratory for Investigating Organismal Response to Climate Change MARSHALL, CD*; CULLEN, JA; AL-ANSI, M; Texas A and M University; Texas A and M University; Qatar University marshalc@tamug.edu http://www.tamug.edu/marshall/

Sea turtles are an interesting model system to investigate organismal responses to extreme habitats. In the Arabian Gulf, air and water temperatures regularly exceed 50oC and 30oC, respectively and marine habitats are hypersaline. Female hawksbill sea turtles in Qatar exhibit a significantly smaller body size and reduced fecundity due to life in this extreme environment. Our goal was to investigate movement and habitat use of hawksbills as part of a Qatari conservation program. Turtles were captured in-water by hand or on the beach post-nesting. Satellite tags were affixed onto the hard shells and deployed. A Bayesian state space model was used to calculate error-adjusted geolocations from Argos-derived movement tracks. We incorporated a behavioral switching model to provide insights into habitat use and GAMMs were used to investigate which abiotic environmental parameters were influential to movement. Hawksbills remained within the Gulf, but moved widely throughout the southern basin. Overall, turtles traveled directly and quickly to distinct shallow habitats and then remained in discrete regions for weeks at a time, presumably foraging. Sea surface temperature had the most significant effect on movement. During summer months, turtles consistently moved toward a steep drop-off consistent throughout the southern Gulf at the 30-40 m isobath. We hypothesize that turtles seek out thermal refuge in these areas since they coincide with the cooler waters of the southern Arabian Gulf loop current. The need to spend time in cooler, deeper habitat may negatively impact energy acquisition, growth and reproductive output.

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