The Kemp's ridley turtle (Lepidochelys kempii) is considered the most endangered sea turtle species in the world and also happens to be the most common sea turtle residing in the nearshore waters of Southwest Florida.
Our estuaries provide the resources that young Kemp's ridleys need to grow to adulthood and females will one day emerge on the primary nesting beaches along the gulf coast of Mexico. Conservation efforts have brought the Kemp's ridley back from the brink of extinction but understanding how turtles live in estuaries and protecting these vital feeding areas will ensure the viability of this endangered species.
Kemp's ridleys are placed temporarily in holding tanks at RBNERR's field station for diet studies. Previous research found Kemp's ridleys are primarily feeding on solitary tunicates (i.e., sea squirts) in the Ten Thousand Islands. Cursory examination of recent samples suggests turtles in this region have shifted their diet to other types of bottom-dwelling organisms such as sponges and colonial tunicates.
Blood and tissue samples are collected from Kemp’s ridleys for stable isotope analysis. The concept behind dietary stable isotope analysis is "you are what you eat", whereby the chemical composition of a turtle's body is related to its diet. The isotope composition of Kemp's ridleys is being compared to those of their prey and various habitat components (mangroves, drift algae, and sessile invertebrates) to characterize a food web in the Ten Thousand Islands estuary. This provides a comprehensive investigation into the trophic ecology of Kemp's ridleys in their estuarine feeding grounds.
Kemp’s ridley blood samples are also being used to predict the sex of these immature turtles. Adult turtles are sexed by the length of the tail, whereby the male turtle has a much longer tail than the female. Other methods are used for sexing immature turtles such as the concentration of the hormone testosterone in the blood.
Kemp's ridleys have also been instrumented with satellite transmitters to provide a better understanding of how this species uses the Ten Thousand Islands estuary and surrounding waters. Turtles typically resided among the island passes and backwater bays of the archipelago. Water temperatures decreased late in the winter and Kemp's ridley exhibited brief seasonal migrations by moving up to 15.5 miles (25 km) offshore or up to 25 miles (40 km) southward but soon returned to their capture site as waters warmed.
The movements of Kemp's ridleys in the Ten Thousand Islands can be followed by visiting www.seaturtle.org.
These studies are supported in part by grants awarded to the Conservancy from the Sea Turtle Grants Program. The Sea Turtle Grants Program is funded from proceeds from the sale of the Florida Sea Turtle License Plate. Learn more at www.helpingseaturtles.org. Satellite transmitters were funded by private donations to the Conservancy. Research activities are conducted under NMFS permit #13544 and FFWCC permit #136.
Tucker, T. and J. Schmid. 2012. Ridley riddles unravel in Florida. Florida Environmental Outreach, Volume 3, Number 4
Tucker, T. and J. Schmid. 2013. Charlotte Harbor in-water studies answer new ridley riddles. Florida Environmental Outreach, Volume 4, Number 3
The Conservancy Science Department has been monitoring loggerhead sea turtle nesting activity on Keewaydin Island since 1982.
Mangrove systems are often called “nature’s nurseries” because they provide habitat and shelter for a variety of animals. They also serve as an indicator of the health of our coastal waterways.
Conservancy of Southwest Florida biologists and partner groups are working to study this invasive species to help identify population management strategies.
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