Telemetry and visual tag as techniques to identify rays distribution and behaviour

Abstract

Marine ecosystems are one of the most difficult environments to study, if you add to this the need to increase the knowledge of decimated species like elasmobranch, whose biology, ecology and even more distribution are, in large part, unknown, it is necessary to look forward for new techniques to improve their knowledge. In the Canary Island, Spiny butterfly ray, Gymnura altavela, is a benthonic ray that occasional visit coastal areas during the summer, but after, its distribution and behaviour are already unknown. Tagging techniques have been used, though acoustic tag implanted in the pectoral cavity and T-tag inserted in the dorsal, to increase the information about displacements of this species between coastal breeding areas and deeper waters, and the circadian rhythms in shallow water areas. But we have also used citizen science data provided by coastal users as diver and anglers.With the aim to collect all this ecological and behavioural data, it has been created a network of fixed acoustic receivers along the southern and eastern coasts of Gran Canaria, but also it has been used an autonomous surface vehicle with an integrating mobile acoustic receiver on board.