Great Hammerhead Shark

Photo: Christa Rohrbach · CC BY-NC-SA

Great hammerheads patrol the deeper sections of the João Vieira wall during the dry season, using the drop-off's complex thermohaline structure to hunt large rays and bony fish in the depth gradient. Their cephalofoil — the distinctive hammer-shaped head — bears electroreceptors distributed across a wide lateral area, dramatically improving their ability to detect prey buried in sand below the wall base. Sightings are unpredictable but the Bijagós' offshore isolation and extremely low fishing pressure makes this one of the few Atlantic locations where great hammerheads still visit reefs in meaningful numbers.