Spatial ecology of hawksbill sea turtles (Eretmochelys imbricata) in foraging habitats of the Gulf of California, Mexico

Abstract

Understanding movement patterns and habitat preferences of endangered species during their most vulnerable life stages is a key step to developing effective conservation strategies that prevent extinctions. Hawksbills (Eretmochelys imbricata) are among the most-imperiled sea turtles and are generally thought to associate with very specific coral and rocky reef habitats. However, in the Eastern Pacific, hawksbills have also been found to have a strong association with mangrove estuaries. Eastern Pacific hawksbills constitute one of the most endangered sea turtle populations globally, and the Gulf of California, Mexico, was recently identified as a potentially important foraging region. Here we analyzed movement patterns of 12 individuals equipped with Argos-linked GPS transmitters. We calculated home ranges using kernel density estimations and found that hawksbills were highly restricted in their movements, spending months to years in areas ranging from 0.05 to 17 km2. Mean sizes of 50% and 95% kernel utilization distributions were 0.72 km2 and 3.8 km2, respectively. Also, 85.6% of hawksbill locations were associated within, or in close proximity to, mangrove estuaries, further highlighting the importance of these fragile ecosystems for hawksbill conservation. The fine-scale resident behavior of hawksbill turtles in foraging grounds presents a unique conservation opportunity while also underscoring the need to identify these sites and work with local communities to protect them.