Evaluating prevalence of external injuries on nesting loggerhead sea turtles Caretta caretta in southeastern Florida, USA

A Ataman,Ja Stoll,Am Gainsbury,Se Hirsch,S Klingshirn,Dm Aoki,Dl Cassill,A Page-Karjian,Mmr Polyak,Jr Perrault,Km Fraser,Ca Manire,Sl Hoffmann

doi:10.3354/esr01149

Abstract

Sea turtles face both anthropogenic and natural threats including boat strikes, fisheries, pollution, and predator attacks. Injuries from anthropogenic sources are more common than naturally caused injuries. The goal of this study was to determine prevalence and cause (e.g. boat strike, entanglement, hook, shark bite) of injuries on nesting loggerhead sea turtles Caretta caretta on Juno and Jupiter beaches, Florida, USA. During the 2019 and 2020 nesting seasons, 450 loggerhead females were examined for external injuries. Injuries were categorized by anatomic location, condition, and cause. We found that 24% of loggerheads had at least 1 injury. Of the 111 injuries found on 107 nesting females, 88% were healed, 9% were partially healed with some scarred tissue, and 3% were fresh injuries. Most injuries (55%) were lateral injuries on the carapace or appendages. We were able to attribute 60 injuries to a specific cause. Boat strikes accounted for 75% of the 60 injuries, shark bites accounted for 15%, fishing hooks accounted for 7%, and entanglements accounted for the remaining 3%. This study provides new insight into the prevalence of anthropogenic injuries relative to natural injuries in loggerhead sea turtles nesting in the most densely nested beach in the Western Hemisphere and can be used to improve conservation management plans through implementation of fishing and/or boating restrictions in the nesting and foraging areas most commonly frequented by sea turtles.

Highlights

Sea turtles are exposed to numerous anthropogenic threats including fisheries bycatch, harvest of eggs and live turtles, coastal development, pollution and plastic ingestion, climate change, and boat interactions (Wallace et al 2011)
In Florida, boat strikes are the most common cause of death in stranded loggerhead sea turtles, accounting for one-third of all loggerhead strandings from 1980 to 2014 (Foley et al 2015, 2019); it was expected that nesting loggerhead turtles on Juno and Jupiter beaches would have a higher prevalence of anthropogenic injuries compared to non-anthropogenic injuries
Commercial lobster, conch, and snapper fisheries operate on the continental shelves of the Bahamas (Moultrie et al 2016), which could increase the interactions of loggerheads with fishing gear, but our study found very few entanglement and hook injuries

Summary

Introduction

Sea turtles are exposed to numerous anthropogenic threats including fisheries bycatch, harvest of eggs and live turtles, coastal development, pollution and plastic ingestion, climate change, and boat interactions (Wallace et al 2011). In Florida, USA, an estimated 3.7% of sea turtle strandings are due to hook and line interactions or some other form of entanglement (only 0.5% from non-fishing gear) (Foley et al 2015). 43% of sea turtle strandings are related to boat injuries in Palm Beach County, Florida, where there is greater boat traffic than in other Florida counties (Singel et al 2008, Foley et al 2015). In addition to injuries being undetectable, scientists must be conservative when determining the cause of death of stranded turtles, which leads to even further underestimations of each injury type (Foley et al 2015). It is critical to understand how turtles are interacting with these threats even if the interaction does not lead to mortality

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