The Florida Hawksbill Project at the National Save The Sea Turtle Foundation continues to lead the way on behalf of Florida’s hawksbill turtles. Two publications are coming out this spring that were generated by the long-term data we’ve gathered concerning hawksbill movements and foraging behavior. The first, entitled Home Range and Movement Patterns of Subadult Hawksbill Sea Turtles in Southeast Florida was published in the March issue of the Journal of Herpetology (Vol. 51, No. 1, 58-67). This paper summarizes the movement patterns we observed among the six turtles who carried satellite tracking devices. These particular turtles were chosen because they had been encountered repeatedly on local reefs, suggesting they had set up some sort of territory. However, there was no solid information revealing the size or shape of these turtles’ personal “home ranges”, nor how each turtle may move about within them. The tracking devices worked well, and revealed that our local hawksbills are, well, homebodies. It seems that each tur- tle centers its activities around some sort of structure (e.g. reef ledge or shipwreck) that provides a safe place for resting and sleeping. During times of activity, the turtles rarely ventured more than a half a kilometer (about a third of a mile) in any direction before returning to their chosen dens. The information we’ve gathered gives great insight to turtle behavior, and con rms the importance of local reefs to these populations. They are arriving and staying in Florida waters because they are finding what they need, and we’d like to keep it that way!
Gotcha! Hawksbill turtles are hand captured either while snorkeling
or scuba diving, depending on the water’s depth. The Florida
Hawksbill Project studies hawksbill populations from Martin through
The other publication will be coming out in May in the journal Chelonian Conservation and Biology. This paper, entitled Foraging Behavior of Wild Hawksbill Turtles (Eretmochelys imbricata) in Palm Beach County Florida, USA (Vol. 16, No. 1) includes a detailed description of search behavior and prey handling derived from video recordings. Hawksbills in this area are accustomed to divers, and allow close underwater approach for observation. For this study, they allowed their for- aging behavior to be recorded up-close by scuba divers, and taught us a lot about how they nd their food among the busy reef community. The results revealed how acute the turtles’ sensory abilities are, and shed light on the unique interactions hawksbills have with their primary diet, sea sponges. Many thanks to my co-authors Barbara Brunnick, Sarah Milton, and Terry Maple for their help and guidance on these projects.
The next set of studies are currently underway! There is a still gap in our understanding of the turtles’ whereabouts before they arrive on the reefs of Palm Beach County, so we are collecting tissue samples that carry a record of their foraging habits from turtles residing in Jupiter all the way down to Key West. From the results, we plan to develop a timeline that traces the development of these individuals along the coastline through their formative years.
To compliment these behavioral studies, we are also addressing some basic physiological questions. Little is known about the blood chemistry, cytology, and other indicators of health among wild hawksbills, so we’ll be analyzing blood, skin, and even (dare I say it) feces to better understand how these turtles ‘tick’ on the inside. These data will provide the first general assessment of wild hawksbill health, and a baseline from which future comparisons can be made. This information will be particularly useful to veterinarians and rehabilitators treating injured or sick hawksbills in captivity.