When it comes to interactions – namely incidental catch and depredation – between fisheries and vulnerable species negative outcomes are seen on both sides.
The Mediterranean and Black Sea region, despite its susceptibility to climate change and other impacts, remains one of the world's biodiversity hotspots due to high species richness, endemism, and the occurrence of rare and vulnerable species, including marine mammals, sea turtles, seabirds, and several species of sharks and rays.
Vulnerable species from these groups play an important ecological role in aquatic ecosystems. Assessing their distribution, abundance and ecological status is crucial to biodiversity conservation, as it helps addressing direct or indirect anthropogenic threats, such as fishing pressure, pollution, habitat degradation, climate change, and the introduction of non-indigenous species.
When it comes to interactions – namely incidental catch and depredation – between fisheries and vulnerable species negative outcomes are seen on both sides. On the one hand, vulnerable species frequently get hooked or entangled in fishing gear and end up as bycatch, injured, or even dead. On the other hand, some of these species (e.g. dolphins, monk seals, sharks) can cause significant economic losses for fishers, removing catch from fishing gear and damaging them.
In recent years, these interactions have received increasing attention, but wide gaps in knowledge on the actual extent of the problem persist. To better understand these occurrences and work towards mitigation solutions, the General Fisheries Commission for the Mediterranean (GFCM) of the Food and Agriculture Organization of the United Nations (FAO) partnered with several organizations and recently launched a Regional plan of action to monitor and mitigate interactions between fisheries and vulnerable species in the Mediterranean and the Black Sea (RPOA-VUL).
This ten-year plan, which directly contributes to the GFCM 2030 Strategy, aims both to reduce incidental catches of vulnerable species and to minimize instances of dolphin depredation.
"Productive fisheries require healthy seas, and ensuring fisheries do not have a significant negative impact on the marine environment is a key aspect of the GFCM's work," said Paolo Carpentieri, Fishery Resources Monitoring Officer. "By shielding vulnerable species from contact with fisheries as far as possible, we can minimize impacts on marine life and sustain healthier seas, as well as help the fishers whose livelihoods are affected by these interactions."
In order to facilitate the identification of priorities and effective implementation of management measures, the GFCM supports its member countries in gathering and assessing missing information in a thorough and standardized way. Its guides to Monitoring incidental catch of vulnerable species in Mediterranean and Black Sea fisheries and Dolphin depredation in Mediterranean and Black Sea fisheries contain protocols for doing so.
Targeted research on vulnerable species
Following the key actions described in the RPOA-VUL, the GFCM launched five pilot projects across all Mediterranean subregions, in collaboration with diverse partners, to reinforce monitoring programmes on bycatch and to identify and test mitigation measures aimed at reducing these interactions.
BirdLife International is working to mitigate the impacts of demersal longlines on seabirds off Spain's Balearic Islands, where shearwater species, including the critically endangered Balearic shearwater, are most at risk.
In Morocco, the Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and contiguous Atlantic area (ACCOBAMS), in partnership with the National Fisheries Research Institute (INRH), has focused on how to reduce the number of sharks and rays incidentally caught in trawl gear, while also studying how to limit dolphin depredation in purse seines.
Elsewhere, ACCOBAMS is working with Marecamp to eliminate dolphin depredation in small-scale fisheries in eastern Sicily, and with Türkiye's Çukurova University to mitigate the incidental catch of sharks, rays, sea turtles and other vulnerable species by trawlers in the north Levant Sea. The latter project includes an assessment of post-release survival rates of sharks and rays.
A fifth project involves a collaboration between WWF-Adria and Croatia's Institute of Oceanography and Fisheries and focuses on reducing captures of sharks and rays in gillnets and combined nets in the northern Adriatic.
"Collaboration is key when addressing vulnerable species bycatch. The pilot project on shark and ray bycatch mitigation will also use conventional tags and work with other researchers who do tagging in the northern Adriatic to collect data from animals that move between east and west in the Adriatic," said Simone Niedermueller, Regional Projects Manager of the WWF-Mediterranean Marine Initiative.
The pilot projects are due to end in 2025, at which point the work plan will expand to incorporate successful measures into future GFCM management plans, as well as consolidate knowledge, and strengthen awareness campaigns and training programmes.
Mitigating cetacean bycatch in the Black Sea
Meanwhile, in the Black Sea, a related project is underway. CetaByM, in partnership with ACCOBAMS, aims to assess and mitigate cetacean bycatch in turbot gillnet fisheries.
Turbot is one of the most valuable species in the Black Sea, but gillnets, the main gear used in turbot fisheries, pose an issue for harbour porpoises, one of the three dolphin species in the region. This cetacean is unable to detect the turbot nets at a distance, and, as a result, becomes frequently entangled.
"Turbot fisheries bring much-needed revenues to many small-scale fishing communities in the Black Sea," said Hüseyin Özbilgin, BlackSea4Fish Coordinator. "But because mortality levels for harbour porpoise are significant, we have been testing measures to mitigate these incidental catches while ensuring that turbot can be fished sustainably in the long term."
The activities in the Mediterranean and the Black Sea are carried out thanks to the support of countries and multiple donors, such as the European Union, which is the main contributor, the Global Environment Facility, and Spain through a voluntary contribution.