First Record of Cetacean Killed in an Artisanal Fish Aggregating Device in the Mediterranean Sea

SIMPLE SUMMARY: Fish Aggregating Devices (FADs) are floating structures used to create shadows and aggregate pelagic fish. In tropical and subtropical waters, the dangerous impact of these structures, due to high levels of bycatch, is well known. We report the first case of a cetacean killed by a FAD and stranded on the coast of Lazio, Italy (central Tyrrhenian Sea). The postmortem evaluation, the difference in degradation (necrosis) between the tail and peduncle, and the marked malnutrition confirm that this specimen was still alive at the time of entanglement. Although this is the first verified case of a cetacean entangled in a FAD in Mediterranean waters, given the widespread use of illegal versions of these devices, the extent of the problem may be greatly underestimated. ABSTRACT: Fish Aggregating Devices (FADs) are anchored floating structures often made with cheap scrapped materials and used to aggregate pelagic fish species under their artificial shadows. Globally, the dangerous impact of FADs is well known. They pose a severe threat as a source of bycatch, as a danger to navigation, and with their high potential to become marine litter. Unintended entanglement and consequent mortality in FADs of vulnerable (e.g., sharks, sea turtles, and cetaceans) and commercial species is a serious concern for several international inter-governmental bodies (e.g., EU, GFCM, and IWC). This work describes the first case of a cetacean, a striped dolphin (Stenella coeruleoalba), entangled in a FAD in the Mediterranean Sea. A young male of striped dolphins was found dead along the coast of Lazio (central Tyrrhenian Sea) with its peduncle entangled in typical debris from illegal/artisanal FADs (i.e., a nylon rope, teared gardening plastic sheets, bush branches, and scrapped empty plastic bottles). Although this is the first confirmed case of a cetacean entangled in a FAD in Mediterranean waters, given the extent of the deployment of anchored FADs, the scale of this type of interaction with protected species might be seriously underestimated. Therefore, actions and monitoring need to be implemented urgently to effectively protect and conserve marine biodiversity.