IMPACT OF SARGASSUM ACCUMULATIONS ON LOGGERHEAD HATCHLING RECRUITMENT TO NEARSHORE WATER ON A RAKED URBAN NESTING BEACH IN FLORIDA.

Hatchling loggerhead turtles emerge from subsurface nests on the beach at night, crawl down the beach and enter the sea. Recently, increases in a floating algae (Sargassum) has been reported in the mid-Atlantic and the Caribbean, resulting in large algal wrack on Florida beaches. The purpose of my study was to determine if these accumulations acted as a barrier, preventing hatchlings from completing their crawl to the sea. To address this issue I recorded seasonal changes in Sargassum density and directly observed when, and under what circumstances, hatchlings could cross the wrack. There was a significant overlap between when Sargassum accumulation peaked and when the turtles emerged, with the result that hatchling recruitment was significantly reduced (by~22%) during the 2020 nesting season. I conclude that algal accumulations represent a significant threat that may impede the recovery of loggerhead populations, that are currently threatened or endangered worldwide.