To cage or not to cage Effectiveness of caging sea turtle nests on Gulf of Mexico beaches


SOCIETY FOR INTEGRATIVE AND COMPARATIVE BIOLOGY
2021 VIRTUAL ANNUAL MEETING (VAM)
January 3 – Febuary 28, 2021

Meeting Abstract


31-9  Sat Jan 2  To cage or not to cage? Effectiveness of caging sea turtle nests on Gulf of Mexico beaches Mazzarella, KT*; Bernhard, MC; Mote Marine Laboratory, Sarasota, FL; Mote Marine Laboratory, Sarasota, FL kristen@mote.org http://www.mote.org/seaturtles

Sea turtle nest depredation has been identified as one of the primary threats to the recovery of loggerhead sea turtles (Caretta caretta) in the Northwest Atlantic Population. In order for a strong recovery to occur, it is recommended that depredation be less than ten percent on a beach. Self-releasing cages and screens have traditionally been utilized to prevent predator intrusion into sea turtle nests. Studies have shown that initial nest depredation increases the likelihood of future depredation on the same nest; therefore self-releasing cages may be used to protect the remainder of the clutch. However, caging is costly both in time and resources, and may have unforeseen impacts on the ecosystem. We analyzed 731 nests at four field sites to determine whether the use of caging after initial depredation (as a predator deterrent) was beneficial to nest survival. In addition, we looked at trends in depredation when caging was not employed. We compared caged and not caged areas across and within years on three barrier islands on the Gulf of Mexico in Sarasota County, Florida, USA. Predators such as raccoons, armadillos, and coyotes are known causes of nest depredations in this region. Preliminary results indicate that for most areas when cages were employed, the depredation rate was higher and/or overall emergence success was lower. Based on these findings, the use of cages after initial depredation, while protecting the remainder of a single nest, may not benefit the overall reproductive output for the population.

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