Fishery-independent data obtained through scientific surveys-at-sea (demersal bottom trawl or beam trawl surveys and pelagic-acoustic surveys) complement fishery-dependent information on multispecies and multigear commercial fisheries in the Mediterranean and the Black Sea. These data are important to acquire direct information on the status, distribution and dynamics of fish stocks and ecosystems at sea, as opposed to those derived from fishery-dependent sources, thereby providing better support to fisheries management.

By collecting data on the number, weight, length, sex, age and maturity stages of a large number of species, scientific surveys-at-sea directly contribute to stock assessments, resulting in more informed estimates of biomass and fishing mortality, thus allowing for a more precise determination of the status of stocks. By collecting data on sex and maturity, surveys also provide the basis for determining areas where juveniles and spawners tend to aggregate and directly contribute to identifying essential fish habitats, which are, in turn, the basis for the identification of potential fisheries restricted areas. Finally, sscientific surveys-at-sea provide a good opportunity to collect data on ecosystems (e.g. macrobenthos, vulnerable species, marine litter).

In response to the lack of comprehensive studies on the biological status of most demersal and pelagic fish stocks at sea in some Mediterranean and Black Sea areas (i.e. geographical subareas [GSAs]), the GFCM established a framework for the implementation of standardized surveys-at-sea in 2019. This framework enables surveys to be carried out in collaboration with national institutes, using harmonized methodologies. Standardized methodologies are crucial for comparing and collating results in a comprehensive way and storing them in common datasets.