Large-scale movements and site fidelity of bull sharks (Carcharhinus leucas) at Reunion Island (Indian ocean)

Abstract

Two bull sharks ( Carcharhinus leucas ) were tagged in coastal waters off Reunion Island in the tropical Indian Ocean and where tracked for 174 and 139 days using both popup satellite archival tags (pSAT) and acoustic tags. Both sharks spent a majority of their time inshore (58.1% and 89.9% in the male and the female respectively). The female performed short excursions. The male alternated residence time along the coast with wide ranging movements and performed one extensive open-ocean excursion near a seamount situated at more than 200 km from the island. The differences in the residency and home range of both sharks probably reflect different patterns of foraging and mating behaviors in the male and the female. These results underline the importance of developing risk-mitigation management taking into account the movements of sharks, and of double tagging in telemetry studies that attempt to measure the degree of fidelity of a species.

Dynamic use of coastal areas by bull sharks and the conciliation of conservation and management of negative human–wildlife interactions

“…This could explain why smaller sharks were more often continuously detected by coastal receivers while for larger sharks, continuous presence spanning several months was less common. These absences may represent large scale offshore excursions leading sharks to leave the island for periods of weeks to months (Soria et al, 2021).…”