Traits biologiques et exploitation du bar commun Dicentrarchus labrax (L.) dans les pêcheries françaises de la Manche et du golfe de Gascogne.

Sea bass Dicentrarchus labrax (Linné, 1758) is a fish of major interest in France and in the British Isles. It is the main target species for some anglers and a growing number of professional fishermen. In spite of this, the reproduction of sea bass in natural environment, the identification of its populations, as well as the fleet participating to and the level of its exploitation are poorly known. Thus, in the perspective of a future management of the bass fisheries, this thesis collected required data for the analysis of the sea bass resource in the English Channel and the Bay of Biscay. A first chapter describes to the principal biological and ecological characteristics of Dicentrarchus labrax. The five following chapters deal successively with: (i) the sexual ripening of the English Channel females and their spawning progress during the reproductive season; (ii) the identification of the sea bass populations in the English Channel and the Bay of Biscay, from genetic (microsatellite loci) and tagging data; (iii) the recreational and professional fishermen who target this species in the same area; (iv) its exploitation by these fishermen; and finally (v) the current state of sea bass stocks.