The Multi-Annual Residency of Juvenile Smooth Hammerhead Shark in an Oceanic Island Nursery

The increased risk of local extinction becomes critical for sharks depending on the narrow and isolated coastal habitats oceanic islands. This includes large pelagic that use such as nurseries, previously hypothesized smooth hammerhead Sphyrna zygaena , least known cosmopolitan sharks. We used a combination acoustic satellite telemetry in juvenile population Faial Pico islands, Azores, mid-north Atlantic, to confirm if this archipelago holds answer questions related their function spatial–temporal stability. Our long-term tracking data showed cluster individual core home ranges specific areas north shore Faial, surface positions from five Argos-linked tagged individuals also clustering overlap those up 1 year. These patterns seem reveal true habitat preference within Faial-Pico island (sub) shark, thus constitute strong evidence area be considered nursery. Some remained nursery 4 years, especially during summers. Sharks diel behavior, typically using inshore nurseries day moving further offshore night, which they activity dove deeper, most possibly feed. speculate feeding opportunities, expanded trophic niche, reduced predatory pressure may key evolutionary driver existence, prolonged use, even at islands by shark. Given these essential fish species, should explicitly included spatial management measures regional scales, play role greater importance Atlantic species.