Loggerhead turtle oceanic-neritic habitat shift reveals key foraging areas in the Western Indian Ocean

Loggerhead sea turtles ( Caretta caretta ) use both oceanic and neritic habitats depending on their life stage, eventually undertaking an ontogenetic shift. Juveniles likely start foraging in a purely opportunistic manner later seek resources more actively. In the Indian Ocean, it is still unclear where oceanic-stage individuals go, what they do, importantly forage. Yet, such information crucial to protect this endangered species from anthropogenic threats as bycatch fisheries. To address this, 67 (66 late juveniles one adult) bycaught open ocean were equipped with satellite tags released Southwestern Ocean between 2008 2021. Most traveled Northwestern used of continental shelf (i.e., largely 0 200-m depth). Using hidden Markov models, we identified three types movements associated traveling, wandering, behaviors. We found that movement characteristics these behaviors differ turtles’ target destination habitat (oceanic vs neritic), highlighting different strategies among presumably same stage (late juveniles). The encountered warmer waters (mean = 27.6°C, min. 20.6°C, max. 33.1°C) than counterparts remaining Southern Hemisphere 22.5°C, 14.6°C, 29.7°C) but at locations comparable biomass potential prey 2.5 g C m -2 , 0.5 10.4 once Northern Hemisphere. It remains obscure why undertook trans-equatorial migration. Once habitats, proportion time spent traveling was considerably reduced (from 33% 19%) allocated instead. light very migrated undergo oceanic-to-neritic Our study sheds behavioral ecology loggerhead identifies important areas Western top-three most densely ones being Gulf Oman, Central Somali Coast, Arabian Sea.