The aim of scientific surveys-at-sea (demersal beam or bottom trawl surveys, pelagic acoustic surveys) is to collect standardized fishery-independent data with a view to improving stock assessments and better support fisheries management. They contribute to the characterization of fishery resources in a given area, in terms of population abundance/biomass at sea, spatial distribution, temporal variation and demographic structure (e.g. length and sex distributions) by collecting data, including sex, maturity and weight, for the estimation of growth parameters of priority species. If the methods employed to carry out any given survey are truly standardized, then it should be possible to compare this information among different areas, subregions and geographical subareas (GSAs). Demersal surveys are also extremely useful for collecting data on ecosystems (e.g. macrobenthos, several vulnerable marine species, marine litter).

In response to the lack of comprehensive studies of the biological status of most demersal and pelagic fish stocks in some Mediterranean and Black Sea areas, a framework for the implementation of standardized regional surveys at-sea was established by the GFCM in 2019, enabling surveys to be carried out jointly with national institutes, using harmonized methodologies or testing new technologies in order to solve the gaps in survey coverage.