The sampling is run from a beam-trawl with the aim of monitoring fish abundance and species composition. Data on benthic species are available since 1977. The parameters measured are (1) total and specific abundances, (2) specific richness. Macrofauna are sampled using a Smith McIntyre grab covering a surface of 0.1 m2. Ten replicates are collected at each sampling date. After collection, the sediment is sieved (1 mm circular mesh) and the retained material is fixed with 10% neutralised formalin prior to analysis in the lab. In the laboratory, organisms are sorted, identified to species level and stored in a 70% ethanol solution.