Argos DCS System Use Agreement of the Month
– May 2016
U.S. Geological Survey – Wetland and Aquatic Research Center
Ecology of Gulf & Caribbean Sea Turtles
We have initiated several tagging and tracking studies on juvenile and sub adult green sea turtles, as well as sub adult and adult loggerheads, and juvenile, sub adult, and adult hawksbills in the Greater Everglades, Caribbean, and Gulf of Mexico.
Our aim is to determine whether these animals are resident in sites where they are captured (US Department of Interior National Parks such as Everglades and Dry Tortugas, US Department of Interior Wildlife Refuges such as Bon Secour, and US Department of Interior National Monuments such as Buck Island Reef).
We also aim to use satellite and GPS tracking to determine whether tagged turtles use the area of capture only as a stopover point in their migration routes. We will establish activity and habitat use patterns through the combined use of mark-recapture, satellite tracking, and molecular genetic techniques. We will also collect stomach contents to perform diet analysis for a subset of turtles from each site and record evidence of disease for all animals captured.
We will uniquely tag each turtle to allow for eventual estimation of probability of recapture and survival. Immediately after marking each animal, we will take standard morphometrics and withdraw a small blood sample (fraction of a milliliter) from the dorso-cervical sinus of each animal for laboratory analysis of mitochondrial DNA. These data will allow us to associate individual animals with known nesting beaches and thus populations of origin. We will use an oral lavage technique to obtain a sample of stomach contents for dietary analysis. We will also collect samples of the local submerged aquatic vegetation and algal cover and identify all samples to the species level and compare these samples to the regurgitated stomach contents. Finally, we will use satellite and GPS tags to track movements of individuals and determine core-use areas. Satellite telemetry has proven to be a successful tracking method for sea turtles as small as juveniles (Hart & Fujisaki 2010), yet most studies to date have focused on sea turtle use of offshore oceanic habitats or open, sandy nesting beaches (Godley et al. 2008). This research specifically addresses habitat requirements that may be necessary for the recovery of these federally threatened and endangered species.
Purpose / Relevance to the South Florida Ecosystem:
This project fits into needs identified by the US Fish and Wildlife Service and the US National Marine Fisheries Service to contribute to recovery of federally listed endangered or threatened species and status survey for rare aquatic and terrestrial reptiles and amphibians in south Florida. The study sites may serve as important refuge or nursery areas, feeding grounds, or developmental habitat for these threatened and endangered sea turtles. It remains to be seen whether juvenile and sub adult green sea turtles are resident for any length of time in particular sites, but if so, their importance in the ecosystem must be accounted for in management plans.
Other Species to be Tagged:
With the success of our sea turtle tagging and tracking program, we are also tagging and tracking endangered American crocodiles and alligators, as well as endangered Snail Kites and Wood storks. Thus, the suite of species that we are tracking in this program is expanding each year. We are excited about this program growth and will work to update our objectives as our pilot projects play out.
For more information: