Leatherbacks Thriving In Florida: A Case Study

Getting a good idea of how many individuals of a certain species are living in the wild can be a challenging science at the best of times, and estimating population demographics for “long-lived” animals can be particularly challenging. For those long-living species that being managed for recovery, longitudinal “mark-recapture” studies are useful to understand variations in life history.

For sea turtles, all of which are listed under the U.S. Endangered Species Act, they may experience multiple types of habitat over the course of their long lives. Leatherback turtles are one such species; in the last two decades, scientists have noted the need to “establish baseline life history data” for the species. The hope is to develop “more accurate assessments of population status and for predicting the capacity of species to recover.”

This study looked particularly at Juno Beach in Florida and, using non-invasive techniques, observed the turtles nightly for ten years spanning 2001-2011. What they found was that the number of individual leatherbacks nesting there is “far greater than the previous estimates,” with 466 individual turtles identified. Of those, there is an average of 100 (with a large range of +/- 41) females nesting there annually. The researchers note that if the survey were to be expanded to cover more Florida beaches, “we suggest that the total population size for Florida should be significantly greater.”

The study confirms that long-lived, late-maturing animals such as Leatherback turtles “spread their reproductive risk quite widely along dynamic beaches,” and this may be a factor helping their recovery. For wild animal and turtle advocates, this research shows not only how Leatherback turtles rely on numerous sites for their reproductive survival, but also shows how useful long-term studies can be in identifying important nesting sites and their related populations.