Johanna FAURE

Elasmobranchs (sharks and skates and rays) are among the species most threatened by fishing globally. Their life-history traits make them particularly vulnerable to overexploitation when there are not subject to a specific management and these species are often caught by fishing vessels targetting other species, they are bycatch. These bycatch, most of the time discarded, sometimes cut off alive contitute a prioritary conservation issue for marine resource management. In the Southern Ocean, elasmobranchs species are few and the most abundant ones are found in benthic habitats at great depths. The french longline fishery targetting Patagonian toothfish (Dissostichus eleginoides), managed by the french collectivity TAAF (Antarctic and Southern French territories) has a cautious stock management approach established from the beginning of the exploitation under the auspices of the CCAMLR (Commision for the Conservation of Antarctic Marine Living Resources). Although the target species represents the majority of catches, between 15 and 30% of the catches are not targetted. Among these species, three skate and rays species, Bathyraja eatonii, Bathyraja irrasa and Amblyraja taaf.

The objectives of my researches are to improve biological and ecological knowledge on each species (growth, fecundity, mortality, etc) and to estimate the populations sizes and dynamics by modelling. An other aspect of my thesis is to establish operational solutions onboard of fishing vessels.

This work will allow to evaluate the vulnerability degree of these skates species bycatch of this fishery, establish monitoring tools for management and support fishermen to reduce skate and rays bycatch.