Résumé
The Seychelles National Plan of Action for Sharks (NPOA-Shark), which came out in 2007, highlighted a fundamental lack of information on the distribution of shark stocks (which are known to be declining worldwide), their biology, and the role that they play in the ecosystem, concluding that this hampered the effective adaptive management of shark stocks and the shark fishery in the Seychelles. The SEYSHA project which started in early 2010, uses acoustic telemetry (acoustic receivers and tags) to study the distribution and migration of coastal sharks around the inner granitic islands. A network of 39 acoustic listening stations (Vemco VR2) have been deployed at various sites around the inner granitic islands of the Seychelles. The sites were chosen after interviewing fishermen and dive operators to collect empirical knowledge on potential key habitats. The strategy of the project is to tag several species as to reflect the multispecies component of the shark community in these waters, such as grey reef sharks (Carcharhinus amblyrhynchos), Tiger Shark (Galeocerdo cuvier), Bull sharks (Carcharhinus leucas) and Hammerhead sharks (Sphymidae sp.). Tagging is currently ongoing (6 grey reef sharks already tagged) and it is expected to have about 20 to 40 sharks tagged by July 2011. Tagging is done through surgery after capture catching using bottom long lines and handlines. Data analyses will concentrate on the movement behavior of sharks around the islands in order to identify any critical habitats. The information provided by the project will be used with other types of information to decide if existing spatial management is effective or whether there is a need to enhance existing management measures. Furthermore the knowledge could assist in the development of policies to reduce conflicts between different stakeholders, particularly shark fishermen and dive operators.