Studies analyzing the spatial and temporal dynamics of demersal resources are based on experimental studies repeated at more or less regular intervals during a specific time of year. The result is the acquisition for each survey of a density table of the species sampled at the different stations. This study was carried out by working on 6 bottom trawl surveys. Each of the surveys was carried out every year at the same period, in June, between 1983 and 1992. The sampling plan used was a random plan stratified according to depth and geographical area. The research vessel used was a bottom trawl (the Drezen 20PM), having a vertical opening of less than 1.8m. The trawl hauls lasted approximately 30 minutes for a depth between 10-150m and 60 minutes for a depth of 150-500m. They systematically targeted bentho-demersal species in Gulf of Lion.