Diya Das

University of the Azores | UAc · Institute of Marine Research - IMAR

A short presentation about the work of the Discardless project in the Azores, on making a decision support tool for fishers to avoid TAC-zero species

A wide diversity of elasmobranch occurs in the Azores, a Portuguese archipelago located by the Mid-Atlantic Ridge. Subject to a commercial fishery for their liver oil until the late 90s, declines in species abundance has led the EU to progressively implement and strengthen catch limits of deep-water sharks, until a TAC 0 was set in 2010. Nowadays, deep-water sharks are still occasionally taken as bycatch of the deep-sea longline fisheries in the Azores. This bycatch, beside constituting a conservation concern, could turn into a consequent socio-economic problem with the upcoming implementation of the Landing Obligation, as deep-water sharks could rapidly choke those fisheries. Several potential mitigation measures are under study. This talk will focus on the work that has been undertaken in close collaboration with stakeholders to study survivability of deep-water sharks. Fish condition and vitality upon release was documented onboard commercial longliners by an observer programme carried out in 2017. Some fishing experiments were further carried out onboard a commercial fishing vessel to test how circle hooks (vs J-hook used in the fishery) affect shark catchability, at-vessel vitality and condition. Post-release survival was assessed through telemetry experiments using acoustic and satellite tags. Results suggest that there is high potential for survival for most species of deep-water sharks, but that it requires cautious handling onboard. A manual and posters to display onboard fishing vessels have been developed to help fishers easily identify deep-water shark species along with best handling practices to increase potential of post-release survival. Keywords: longline bycatch, deep-water sharks, survivability, onboard handling, stakeholder involvement

A vulnerable species group, such as, the elasmobranchs, in a data-deficient context presents a complicated management problem. Evidence suggests that the Azores islands, a remote archipelago on the Mid-Atlantic Ridge, serve essential functions in the life-history of species across taxa. The diversity of marine resources within its EEZ are exploited by local to international fleets, and the full extent of fishing pressure can often be underestimated. Although sharks and rays appear to be of minor importance in the fishery, the possibilities of illegal, unreported, and unregulated fishing raises concerns about these threatened species. However, this group has failed to attract management attention, visible in the lack of regional studies focused on biodiversity, ecology, or threats of elasmobranchs. Our work attempts to review and update the information on elasmobranchs of the Azores and identify potential threats, mainly by the local fisheries. We aim to highlight knowledge gaps that require further research and conservation actions. We (1) update the annotated checklist of elasmobranch species, (2) compare species distribution across a biogeographically similar section of the North Atlantic, and (3) analyze the interaction of elasmobranch species with local fisheries. We confirm 61 chondrichthyan species for the Azores (39 sharks, 17 rays, and 5 chimaeras), adding 19 species to the previous annotated checklist of 1997. The Azores elasmobranch species assemblage most resembles Madeira, the neighboring Macaronesian archipelago. Biogeographic affinities between the chosen regions of the North Atlantic are reflected in the taxonomic structure of families. Although underestimated in the local fisheries, elasmobranchs constitute a regular but highly variable portion of total landings. Misreporting and misidentification is perhaps the greatest concern in the local fisheries records, further aggravated by few existing catch regulations for elasmobranchs. Local knowledge indicates that the Azores serves as essential habitat for at least a few species in coastal areas and shallow seamounts, and potentially so for a number of deep-sea elasmobranchs. The intersection of fishery threats and local essential habitat functions around the archipelago warrants greater research effort and studies.