Common coastal foraging areas for loggerheads in the Gulf of Mexico: Opportunities for marine conservation

Abstract

Designing conservation strategies that protect wide-ranging marine species is a significant challenge, but integrating regional telemetry datasets and synthesizing modeled movements and behavior offer promise for uncovering distinct at-sea areas that are important habitats for imperiled marine species. Movement paths of 10 satellite-tracked female loggerheads (Caretta caretta) from three separate subpopulations in the Gulf of Mexico, USA, revealed migration to discrete foraging sites in two common areas at-sea in 2008, 2009, and 2010. Foraging sites were 102–904km away from nesting and tagging sites, and located off southwest Florida and the northern Yucatan Peninsula, Mexico. Within 3–35days, turtles migrated to foraging sites where they all displayed high site fidelity over time. Core-use foraging areas were 13.0–335.2km2 in size, in water <50m deep, within a mean distance to nearest coastline of 58.5km, and in areas of relatively high net primary productivity. The existence of shared regional foraging sites highlights an opportunity for marine conservation strategies to protect important at-sea habitats for these imperiled marine turtles, in both USA and international waters. Until now, knowledge of important at-sea foraging areas for adult loggerheads in the Gulf of Mexico has been limited. To better understand the spatial distribution of marine turtles that have complex life-histories, we propose further integration of disparate tracking data-sets at the oceanic scale along with modeling of movements to identify critical at-sea foraging habitats where individuals may be resident during non-nesting periods.