Conservation implications of internesting habitat use by Loggerhead Turtles Caretta caretta in Woongarra Marine Park, Queensland, Australia

Abstract

We studied internesting habitat use by Loggerhead Turtles Caretta caretta with radio telemetry and by visual sightings of paint-marked turtles in Woongarra Marine Park, adjacent to the major mainland nesting rookery in Queensland. A high concentration of females occurs within the Park during the early phase of the internesting period as ovulation and shelling of eggs occur. From 36?72 hr following oviposition, activity ranges and swimming rates were greatly reduced. About day 9 after oviposition, turtles resumed higher swimming rates and wider activity ranges and were as likely to be outside protected management zones as within. Movements were generally within 10 km north or south of the rookery, limited to 1?2 km of the coast rather than offshore oriented and were independent of currents. A different pattern was exhibited after the final nest of the season: females departed the region quickly, with little of the localized movement characteristic of the internesting period. Over 89% of the nesting females were susceptible to trawling at some time during their internesting period as they swam outside the Protected Management Area. The likelihood of turtle-trawler interactions along the Woongarra coast and the potential of turtle excluder devices (TEDs) as a conservation measure are discussed. TED use provides a broadly applicable management option that can be combined with spatially or temporally restricted trawling zones.