MEPS 564:235-240 (2017)  -  DOI: https://doi.org/10.3354/meps12013

ABSTRACT: Green turtles Chelonia mydas spend the first several years of life in oceanic nursery habitats before recruiting to coastal developmental habitats as juveniles. Traditional green turtle life history models assume that the ontogenetic habitat shift is permanent and associated with a transition from omnivory to herbivory, and that seasonal movements between temperate foraging sites to thermally appropriate overwintering sites occur within the neritic zone. We deployed satellite transmitters on juvenile green turtles captured at a temperate latitude foraging site to document seasonal movement patterns and identify overwintering strategies. We found that the majority (73%) of juvenile green turtles left the neritic zone and exploited oceanic habitats during the late fall or winter. While previous studies have indicated that juvenile green turtles may spend time in deep (>200 m) waters near the continental shelf break during the winter, ours is the first to report long-distance migratory movements, and presumably foraging, in the open ocean. Our findings contradict the widely held notion that juvenile green turtles adopt a strictly herbivorous, benthic foraging pattern after recruitment to the neritic zone and illustrate that there is plasticity in the ontogenetic habitat shift. These results have important implications for understanding somatic growth and population dynamics for this endangered species.

KEY WORDS: Sea turtle · Movements · Foraging · Growth · Ontogenetic shift · Seasonal