Satellite Tagging of Blue Sharks (Prionace glauca) in the Gulf of Lions: Depth Behaviour, Temperature Experience and Movements – Preliminary Results

Abstract

The lack of reliable fishery-dependent data and fundamental understanding of the biology of most shark species causes concern for the sustainable management of shark populations in the Mediterranean Sea. The blue shark (Prionace glauca), a wide-ranging shark occurring in all tropical and temperate seas, is also one of the most heavily fished sharks in the world and so in the Mediterranean. In other oceans, its distribution is depicted as complex with spatial and temporal segregation by sex and size. In the Mediterranean Sea, movements and behaviours of this species are poorly known. The study aims at investigating on habitat occupancy, residency times and migratory pathways as well as providing behavioural data on temperature experience and swimming depth of the blue shark. This study strives to identify habitats and regions that are essential for the survival of sharks, while also determining when and where sharks are most vulnerable and will assist in the conservation of the species. The use for the first in the Mediterranean Sea of different types of satellite tags is proposed to investigate the ecology of this species. The preliminary results of the “smart tags” deployed on eight individuals are presented.