Impact of Sargassum Accumulations on Loggerhead (Caretta caretta) Hatchling Recruitment in SE Florida, U.S.A.

Abstract

Schiariti, J.P. and Salmon, M., 2022. Impact of Sargassum accumulations on loggerhead (Caretta caretta) hatchling recruitment in SE Florida, U.S.A. Journal of Coastal Research, 38(4), 725–734. Coconut Creek (Florida), ISSN 0749-0208. Hatchling loggerhead turtles emerge from subsurface nests on oceanic beaches at night, then crawl toward and enter the sea. Recently, increases in a floating algae (Sargassum spp.) have been reported in the mid-Atlantic and Caribbean, resulting in large accumulation on Florida's beaches. The purpose of this study was to determine if, during the 2020 nesting season, these accumulations acted as a barrier that prevented the hatchlings from crawling to the sea. Seasonal changes in Sargassum density were recorded to determine when, and under what circumstances, hatchlings could cross the accumulated wrack. There was a significant overlap between when Sargassum accumulations peaked and when the turtles emerged, with the result that during the 2020 nesting season the number of hatchlings that entered the ocean was reduced by an estimated 22%. These results suggest that algal accumulations represent a significant threat that could potentially impede the recovery of loggerhead populations that currently are either threatened or endangered, worldwide.