Padrão de deslocamento e uso de habitat dos tubarões-tigre (Galeocerdo cuvier) no Arquipélago de Fernando de Noronha.

Abstract

The tiger shark is a large, globally distributed opportunistic predator that exhibits migratory behavior, being able to move between different habitats due to the influence of various factors, such as water temperature, feeding and reproduction. Their large-scale movements may increase their vulnerability to fishing pressures. However, marine protected areas, such as the Fernando de Noronha Archipelago, can be effective sites for their conservation. Therefore, it is important to understand how these animals interact with their habitat. The aim of this study is to characterize the patterns of displacement and habitat use of tiger sharks in the Fernando de Noronha Archipelago, in an attempt to understand whether, despite being a migratory species, tiger sharks have residential occupation in the area. We used passive acoustic telemetry techniques, where six specimens were captured on a scientific expedition and five were surgically fitted with an acoustic transmitter that was detected by 10 acoustic receivers strategically located around the archipelago for 164 days. Analysis of habitat use using the Kernel method revealed that, althogh they use the entire study area, tiger sharks preferentially occupy the Mar de Dentro region. In addition, a network analysis was carried out to understand the movement patterns of the tiger sharks monitored, which showed that the movement of these individuals connects all regions of Fernando de Noronha in different intensities, but that Praia do Sancho, Cacimba do Padre and Baia dos Golfinhos, in the Mar de Dentro region, exhibit the greatest connection strengths. Thus, individuals are highly likely to move between the three areas and link the Mar de Dentro and Mar de Fora regions. The patterns of habitat use, and displacement indicate that the Archipelago may be a suitable place for tiger sharks to occupy, with the availability of prey and favorable characteristics for the species to reproduce. Therefore, the results of this study may contribute to improving conservation strategies for tiger sharks in the Conservation Units of the Fernando de Noronha Archipelago.