Exposure of loggerhead sea turtle nests to waves in the Florida Panhandle

Wave wash-over poses a significant threat to sea turtle nests, with sustained exposure to waves potentially resulting in embryonic mortality and altered hatchling locomotor function, size, and sex ratios. Identifying where and under what conditions wave exposure becomes a problem, and deciding what action to take (if any), is a common issue for sea turtle managers. To determine the exposure of sea turtle nests to waves and identify potential impacts to hatchling productivity, we integrated a geographic information system with remote sensing and wave runup modeling across 40 loggerhead nesting beaches used by the Northern Gulf of Mexico Loggerhead Recovery Unit. Our models indicate that, on average, approximately 50% of the available beach area and 34% of nesting locations per nesting beach face a significant risk of wave exposure, particularly during tropical storms. Indeed, 42.3% of all nest locations reported wave exposure, which resulted in a 45% and 46% decline in hatching and emergence success, respectively, relative to their undisturbed counterparts. Nesting frequency at each beach and exposure to waves were considered to identify priority locations where efforts are most warranted to address wave exposure impacts. Nine beaches in the eastern Florida Panhandle were identified as priority sites for future efforts such as research and development of management strategies. This modeling exercise offers a flexible approach for a threat assessment integration into research and management questions relevant for sea turtle conservation as well as for other beach species and human uses of the coastal environment.