Time for a U-turn for an ecosystem-based management of shrimp fisheries in the Sea of Marmara

This study aims to inform sustainable fisheries management strategies by evaluating the contribution of beam trawl fisheries, mainly targeting deep-water rose shrimp Parapenaeus longirostris, to bycatch in the Sea of Marmara (SoM). Field studies were conducted between May 2022 and April 2023 in collaboration with local fishers operating in shrimp fishing areas in southern SoM. The study encompassed 120 beam trawl surveys covering 8.88 km² across randomly selected stations. Biomass and catch per unit effort were analyzed to quantify catch composition and bycatch levels. Over the study period, 3925 kg of marine organisms representing diverse species were collected, with the target species, deep-water rose shrimp, comprising only 24.6% of the retained catch. The remaining catch consisted of bycatch, including both commercial and non-commercial species, as well as the incidental capture of sensitive taxa. Through field-based assessments, this study highlights the inadequacy of current mitigation efforts to address the destructive nature of the beam trawl fishery in the SoM. Despite gear modification efforts to date to increase selectivity and reduce bycatch, no intervention has been entirely successful in eliminating the ecological footprint. Data-driven insights argue for new management strategies, prioritizing alternative solutions and ecosystem-based fisheries management.