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Centuries of exploitation have depleted sea turtle populations to a fraction of their historical numbers. Successful conservation depends on protection of these endangered species, their habitat and predators — all of which vary greatly among coastal communities. The continued decline of sharks (sea turtles’ natural predators) and human-driven changes in habitat can affect turtle behavior and habitat use.

FIU researchers measure the shell of a sea turtle in a small boat

The Heithaus Lab has been involved in sea turtle research since 1997 when initial studies began as part of the Shark Bay Ecosystem Research Project (SBERP) in Western Australia. Studies have since expanded to several locations including the Caribbean Sea (French West Indies and Abaco, Bahamas), Madagascar, and globally using data collected from Global FinPrint. Using a combination of observational and experimental studies, we investigate the role of predation risk from large sharks in shaping sea turtle behavior; the effects of environmental factors on diving behavior, foraging ecology, and individual specialization in behavior; and the role of sea turtles in seagrass and coral reef ecosystems.

Species

Green Turtle

Green turtles (Chelonia mydas), who primarily graze on seagrass, have the potential to affect seagrass communities; thereby understanding the effect of predator presence on grazing behavior is important. Many regions are implementing sea turtle and even shark protection, but many marine ecosystems within these regions are strongly affected by human generated stressors.

In 2014, the Heithaus Lab expanded their study of Caribbean sea turtles to the French West Indies (Guadeloupe, Martinique and St. Martin) to investigate foraging preferences for native versus invasive seagrass species and whether green turtles might facilitate or attenuate the invasion through their choice of habitats and feeding patterns. As part of the Shark Bay Ecosystem Research Project we also study the foraging behavior and habitat use of green turtles relative to risk of predation by tiger sharks (Galeocerdo cuvier) and food availability.

Green turtle

Hawksbill Turtle

Hawksbill turtles (Eretmochelys imbricate) are understudied relative to other species of sea turtle. Known to be predominant sponge predators, they spend their adult life foraging on coral reefs. Previous research indicates that hawksbills have the potential to play a vital role in shaping marine ecosystems despite their small population numbers; however, the effects of turtle foraging on community dynamics between prey and habitat remain largely unclear. InNosy Be, Madagascar, the goal is to develop a better understanding of how habitat quality affects hawksbill sea turtle distributions and what role these turtles play in coral reef ecosystems.

Hawksbill turtle

Loggerhead Turtle

Loggerhead turtles (Caretta caretta) can be found worldwide from tropical to temperate waters, migrating long distances for foraging and nesting purposes. As carnivores, loggerheads feed on crustaceans, mollusks, sponges, cnidarians, and bivalves. Loggerhead sea turtles are some of the largest predators of benthic invertebrates and may play an important role in structuring the composition and dynamics of benthic communities. Currently, Loggerhead populations are being studied by the Shark Bay Ecosystem Research Project through the use of satellite tags in order to obtain more information on loggerhead migrations,movements, and habitat use.