Estimation of technical interactions due to the competition for resource in a mixed-species fishery, and the typology of fleets and metiers in the English Channel

In a multi-gear and multi-species artisanal fishery, the level of technical interactions (i.e. the competitive externalities resulting from a shared e xploitation of common resources or fishing grounds) among various fishing u nits is high. Assessing these technical interactions is of great importance for fishery management, as any control applied to one fishing unit may hav e positive or negative effects on others. The magnitude and direction of th ese effects cannot be easily measured, unless all fishing units and species in the fishery are considered simultaneously. Technical interactions are p articularly important in the complex artisanal fisheries of the English Cha nnel. Using a bioeconomic model of the English Channel that incorporates al l the major fishing units (the BECHAMEL model), we describe a method for me asuring and classifying the technical interactions due to the competition f or resource (stock externalities). The results are used to develop a typolo gy of metiers and fleets based on their overall level of interaction for th e resource. We also define fleets and metiers as structuring, dependent, in termediate or autonomous. (C) 2001 Ifremer/CNRS/Inra/IRD/Cemagref/Editions scientifiques et medicales Elsevier SAS.