| The average trophic level of the landings of the species landed by the french fleets in the Bay of Biscay is dropping since 30 years, according to the worldwide range observations of Daniel Pauly. The effects of the ecosystemic, institutional and economic factors of this drop are studied with two complementary approaches, a time series analysis and the interpretation of the phenomenons thanks to a bio-economic model. The major factors which could interact with the exploitation from 1973 to nowadays have been analysed. The short term study of the productions and the productivity of tree large trawler fleets from south brittany showed that they adapted according to their specificities to the constraints enforced by the stocks or the prices. At the larger... |
