Variabilité spatiale et temporelle d'une pêcherie au filet dans le golfe du Lion. Essai d'évaluation de l'impact d'un récif artificiel

The laying out of an offshore site in the gulf of Lion has been realized by immersion of concrete structures in 1985. Two complementary studies have been conducted in order to estimate the impact of such artificiel reef. Gillnet fishery surveys have been done in the vicinity of the structures and also on a control site. Moreover the local profcssional fishery has been investigated for two periods of 16 months, one berore and one arter the reef immersion. The results of the gillnet surveys have already been submitted to publication and the present study displays the investigations concerning the local fishery. It has been shown by the gillnet fishing surveys that the artificial reef led in their very close vicinity to variations in marine species composition and this, as soon as the second year following the reef immersion. Nevertheless, at the same time, the presence of the artificial reef did not entail any change in the fishermen exploitation strategies. The landing investigations did not allow to identify any significative modifications in the species composition of the captures, related to the reef presence .