Project Title: Adult green turtles (Chelonia mydas) of the Archie Carr National Wildlife Refuge 2014
Project Manager: Dean Bagley
Organization: University of Central Florida (Research and Educational Institute)
Grant Amount: $24,422.00
Summary: The project will satellite track four adult green turtles (two males and two females) from the Carr Refuge in 2014 and conduct studies specific to each gender. Both males and females will be sampled for genetics, and stable isotope analysis. To infer post-nesting migration destinations, isotopic signatures of satellite turtles will be compared to signatures from an additional 50 nesting females as part of a separate study. We will follow the satellite-tracked females to determine clutch frequency, site fidelity, internesting location and foraging grounds. We will attempt to encounter each female each time she nests and mark those nests for assessment of reproductive success. Satellite data will show how long each sex remains at the beach, the migratory routes used and final destinations at their respective foraging grounds. Areas of special use at the nesting beach will be identified for each sex, and kernel home range estimates will be generated when they return to foraging areas.
Results: This grant was provided for the purpose of attaching satellite transmitters to four adult green turtles, two male and two female. Because 2014 was a low nesting year, we were unable to find male green turtles, and as a result those two transmitters were held until 2015, when they were successfully deployed. The two nesting females in 2014, and one other (Janet), not provided by this grant, were displayed on the website of the Sea Turtle Conservancy (STC). When the remaining two transmitters were deployed on the first two males in 2015, they also became part of the STC tracking site. The turtles were given names, making it easier to follow them online: Linda, Dawn, Mario and Brian. While it was not possible to encounter each female at each nest, satellite data indicated that the two females laid six nests each during the nesting season. For the first time, VHF transmitters were attached to females at the same time as the satellite transmitters. Dawn had lost her VHF unit before we saw her at nest number two; Linda still had her VHF tag at a false crawl prior to nest five, but was not seen again. We did not find the VHF transmitters helpful and will not be using them again. Dawn lost her satellite transmitter after nest number three, but students encountered her incidentally at nests four and six, which allows us to know that she was here at least that long. We cannot exclude the possibility of a seventh nest but she was not seen again. Average number of days tracked for the two females and two males was 107.5 (range 33-171). Total distance traveled by each of the four turtles while they were satellite-tracked ranged from 201 to 1297 kms. Migration movements were constant, swimming both day and night, until destinations were reached. Dawn was the first turtle in this study to lose her transmitter while she was still at the nesting beach. This is always a possibility as we are deploying at the very outset of the nesting season when mating is still occurring, but this is the first instance in which it has occurred. Linda left the Carr Refuge immediately after her last nest on 25 July 2014 and returned to forage just NW of Big Pine Key. Mario spent seven weeks at the nesting beach before making his direct migration south along the coast to the west side of the Marquesas Keys. He remained in this area until we stopped receiving transmissions on 20 October 2015, at 171 days. Brian remained off the nesting beach for nearly eight full weeks before taking a direct route to Rebecca Shoals (located between the Marquesas and Dry Tortugas) where he foraged for a short while before meandering back east to the Sambo Keys, south of Stock Island. He remained there until his transmitter stopped sending signals on 22 September 2015 at 127 days.