A study conducted around Andros Island in the Bahamas revealed that some individuals display remarkable site fidelity, choosing to stay close to home rather than embarking on extensive migrations.

This study revealed that great hammerheads were found year-round in Andros waters. These findings were surprising, as earlier studies (Guttridge et al. 2017) found that great hammerheads in the Bimini Islands migrated in late spring (start of the wet season). Only two great hammerheads (both females) of eight were tracked outside the Bahamas EEZ, with all others predominantly using the eastern shoreline of Andros Island.

Factors influencing site fidelity

The study suggests that the abundance of resources, particularly prey availability, plays a significant role in this behaviour. The waters surrounding Andros Island offer a rich supply of prey, such as stingrays, which may reduce the necessity for these sharks to travel long distances in search of food. This localised abundance allows great hammerheads to meet their dietary needs within a confined area.

Water temperature is an important abiotic factor that influences key metabolic and physiological processes for sharks. Given the proximity of Andros’ east side to deep shelf waters, in which an individual could use the cooler waters for rest after expending energy on the flats, Andros not only offers year-round resource availability but also access to great hammerheads’ preferred thermal habitat during the wet and dry seasons.