By Conservancy Research Manager Dr. Jeff Schmid
Estuarine waters in Southwest Florida provide important feeding habitat for young Kemp’s ridleys, considered the world’s most endangered marine turtle. There have been tagging studies in the Ten Thousand Islands region that demonstrated Kemp’s ridleys remain faithful to certain feeding areas for a number of years. Each turtle is given a metallic tag on the trailing edge of the right flipper and a microchip implanted in the left flipper, each with a unique code to identify individuals. Kemp’s ridleys have been recaptured in the same area multiple times within a year and over multiple years, hence the faithfulness or “fidelity”. Recoveries of tagged turtles reveal endpoints but offer little information on their activities between capture and recapture.
Case in point, we recently “re-recaptured” a Kemp’s ridley in the Ten Thousand Islands on 26 October 2016 which was originally tagged on 27 April 2015 and later recaptured on 29 April 2016. We determined the turtle had been eating crabs from diet samples collected during each capture event. However, we do not know to what extent this Kemp’s ridley had used the waters of the Ten Thousand Islands as feeding habitat during the year and a half at large. Satellite telemetry (i.e., tracking animals from space) allows us to remotely investigate the free-ranging behavior of turtles and thus fill the gaps of mark-recapture studies. A transmitter is attached to the turtle’s carapace and a message is transmitted to the Argos satellite system each time the turtle surfaces to breath. The satellite data are then sent to ground-based facilities and estimates of the turtle’s location are provided in near real-time.
As part of our ongoing tracking studies, the recaptured Kemp’s ridley was outfitted with a satellite transmitter before being released back into Gullivan Bay in the upper Ten Thousand Islands. The transmitter is sponsored by John and Carol Walter and the turtle is named “Lucy Helen” after their granddaughter. Lucy Helen has thus far remained in Gullivan Bay despite the occurrence of red tide, a harmful algae known as Karenia brevis that produces toxins detrimental to marine life. Former tracking studies in the Charlotte Harbor estuary demonstrated that Kemp’s ridleys may be able to detect and subsequently avoid areas with high concentrations of red tide. Additional satellite tags will be deployed in the Ten Thousand Islands during the following months to investigate Kemp’s ridley movements relative to the prevailing environmental conditions (water temperature, harmful algae blooms, etc.). The tracking data will also be used to identify Kemp’s ridley foraging areas in the Rookery Bay National Estuarine Research Reserve and surrounding marine protected areas.
Our research activities are conducted under NMFS permit #13544 and FFWCC permit #136. Satellite transmitters are funded by private donations to the Conservancy. Additional funding is provided through grants awarded from the Sea Turtle Grants Program which is supported by proceeds from the sale of the Florida Sea Turtle License Plate. Learn more at www.helpingseaturtles.org.