Data on demersal and mega-benthic species were sampled in the context of the MEDITS suveys carried out on the Spanish Mediterranean continental shelf since 1994. MEDITS is a program of bottom trawl surveys developed annually in the Mediterranean, in which all the participants use the same gear, sampling protocol and methodology, with the objective to evaluate the abundance and distribution of stocks, independently of the data provided by commercial fisheries, and to assess the impact of the fishing activity on the environment.