Modeling and mapping isotopic patterns in the Northwest Atlantic derived from loggerhead sea turtles

Stable isotope analysiscan be used to infer geospatial linkages of highly migratory species. Identifying foraging grounds of marine organisms from their isotopic signaturesis becoming de rigueur as it has been with terrestrial organisms. Sea turtlesare being increasingly studied using a combination of satellite telemetry and stable isotope analysis; these studies along with those from other charismatic, highly vagile, and widely distributed species (e.g., tuna, billfish, sharks, dolphins, whales) have the potential to yield large datasets to develop methodologies to decipher migratory pathways in the marine realm. We collected tissue samples (epidermis and red blood cells) for carbon ( δ13C) and nitrogen ( δ15N) stable isotope analysisfrom 214 individual loggerheads (Caretta caretta) in the Northwest Atlantic Ocean (NWA). We used discriminant function analysis(DFA) to examine how well δ13Cand δ15Nclassify loggerhead foraging areas. The DFA model was derived from isotopic signaturesof 58 loggerheads ...