Evaluating publicly available reported shark and ray catch data in industrial fisheries: A global review to inform assessment and conservation

Several species of sharks and rays are experiencing severe population declines, yet clarity about where to focus management and conservation actions is lacking. Industrial tuna fisheries target or incidentally catch (i.e., “bycatch”) vulnerable shark and ray (i.e., elasmobranch) species in significant numbers, with potentially long-lasting impacts. However, due to often limited researchgrade data collection and access, the contribution of these fisheries to elasmobranch mortality is often incomplete, regionally focused, and poorly understood. Here, we used quantitative and qualitative approaches to quantify publicly accessible pelagic elasmobranch catch data in four tuna Regional Fisheries Management Organizations (tRFMOs) and describe the scale and potential impact of industrial tuna fisheries on 13 threatened oceanic shark species and 9 mobulid ray species. We compiled publicly reported catch data and estimated that tRFMO-managed purse seine and longline fisheries reported an annual mean of 2.4 million individual pelagic elasmobranchs (91,954 tonnes) over the last years with available data (2013–2019), corresponding to roughly one elasmobranch reported for every two tonnes of tuna caught. Longline fishing is responsible for >90% of this reported catch, due primarily to the commercial status of some elasmobranchs. Based on existing stock assessments, only 20% of the examined populations have been formally assessed, and assessments are uncommon for species that are not commercially targeted. These results present a broad characterization of publicly available global and regional reported elasmobranch catch data, and can guide improved data collection and access, research, and conservation efforts for increasingly vulnerable oceanic elasmobranchs.