Finally, surveys are extremely useful to collect data on ecosystems, such as macrobenthos, several vulnerable marine species and marine litter.
Mediterranean and Black Sea countries convene every year at the session of the General Fisheries Commission for the Mediterranean (GFCM) of the Food and Agriculture Organization of the United Nations (FAO) to adopt decisions for fisheries conservation and management in the region. This year, decisions included reinforcing management measures for numerous GFCM priority species, setting new catch limits and establishing a new fisheries restricted area (FRA).
The annual session represents both the beginning and the end of the GFCM fisheries advisory process: underpinning all adopted decisions is the best available scientific advice, which is based on data collection and analysis. In this context, a significant amount of data is collected through implementing surveys-at-sea.
Why conduct surveys-at-sea?
Complementing fishery-dependent information on multispecies and multigear commercial fisheries in the Mediterranean and the Black Sea, data obtained through scientific surveys-at-sea are very useful to acquire direct information on the status, distribution and dynamics of fish stocks and ecosystems and improve stock assessments, providing better support to fisheries management.
Countries in the region conduct several types of surveys-at-sea, of which the most common are demersal and acoustic surveys. Demersal surveys use bottom or beam trawls to collect information on stocks of species that live close to the seabed, while acoustic surveys use sonar, in combination with mid-water trawls, to quantify stocks of species that live in the water column. While they employ different methodologies, these surveys share a common objective: to quantify species biomass levels at sea and monitor population trends and distribution over time.
In 2019, the GFCM established a framework for the implementation of standardized surveys-at-sea across different countries, complementing existing surveys with the aim of achieving optimal regional coverage. This framework enables surveys to be carried out in collaboration with national institutes, using harmonized methodologies. Standardized protocols are crucial for comparing and collating results in a comprehensive way and storing them in common datasets.
Today, all scientific surveys conducted in the Mediterranean Sea are standardized. In the Black Sea, beam trawl surveys for rapa whelk and demersal surveys are standardized, while acoustic surveys are in the process of being standardized.
"International collaboration is key for implementing standardized surveys for shared stocks," said Elisabetta Betulla Morello, GFCM Senior Fishery Officer. "This synergy is exemplified by our capacity development programmes MedSea4Fish and BlackSea4Fish, where training conducted on board ensures proficiency in survey techniques and catch handling. This not only enhances data accuracy and comparability but also equips participants with essential skills for effective resource management," she added.
"Standardizing survey methodologies helps experts from several countries to better understand the fluctuations of fish resources and marine organisms and identify hotspots, for example nursery areas or vulnerable marine ecosystems," said Sharif Jemaa, a researcher at the National Council for Scientific Research in Lebanon.
Survey-at-sea, collecting data in Lebanon (left) and in Türkiye (right) ©FAO-GFCM/ Ralph Azar, ©FAO-GFCM/Tamer Günal
The GFCM fisheries advisory process and survey data
Surveys collect data that provide key information on the number, weight, length, age, sex, and maturity stages of a large number of species. This information directly contributes to stock assessments, resulting in more informed estimates of biomass and fishing mortality, thus allowing 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.
Finally, surveys are extremely useful to collect data on ecosystems, such as macrobenthos, several vulnerable marine species and marine litter.
Once collected, the data are submitted to the GFCM. Experts and other stakeholders from the region then come together and jointly analyse the findings, elaborate forecasts, identify priorities and guide management planning. Based on this cumulative work, the GFCM advisory committees formulate scientific, social and economic advice. This is what forms the basis of the binding recommendations and other resolutions – collectively known as decisions – that the GFCM adopts every year at its annual session.
Focusing on data collected by surveys-at sea, improved estimates of fishing mortality and stock biomass contribute better information towards identifying the best potential management options to ensure sustainable exploitation. Examples of adopted decisions based on this advice include GFCM recommendations establishing catch limits for anchovy and sardine in the Adriatic Sea, for deep-water red shrimps in the Strait of Sicily, Levant Sea and Ionian Sea, and turbot in the Black Sea, as well as effort limits for demersal fisheries in the Adriatic Sea and management measures for rapa whelk in the Black Sea. Similarly, based on identified essential fish habitats, the GFCM adopts recommendations establishing fisheries restricted areas (FRAs) for their protection. Examples include the Jabuka/Pomo Pit FRA in the Adriatic Sea and the three FRAs in the Strait of Sicily: East of Adventure Bank FRA, West of Gela Basin FRA, and East of Malta Bank FRA.
Throughout the advisory process, compliance and enforcement are key to ensure that mandatory requirements, data quality metrics and regulatory frameworks are effectively implemented. This includes complying with the requirements of FRAs and respecting established catch limits.