Abstract
Summary Objective: The North-East Atlantic stocks of porbeagle and spurdog are listed as Critically Endangered under the IUCN Red List. Currently, these sharks are caught in target fisheries and as a bycatch in longline, trawl and gillnet fisheries. Reduced quotas and size restrictions will be introduced in 2009, and there have been discussions at a European level on setting a zero TAC. Further mitigation measures such as area or seasonal closures, or technical measures to limit by-catch, are also possible. However, limited knowledge of the movements and distribution of these species, and their survivorship after capture, severely hampers the evaluation of proposed policies.To evaluate the efficacy of current and other potential management measures it is necessary to collect evidence on the risk of capture and the survivorship of caught & discarded porbeagle and spurdog. To do so, information is required on the geographic and seasonal overlap of porbeagle and spurdog and the fisheries that exploit them. This information can be used to identify the times of year or particular localities where these sharks may be most vulnerable to capture. This understanding should then be combined with assessments of the survivorship of porbeagle and spurdog after being discarded to develop a qualitative assessment of the vulnerability of stocks to fisheries (directly as retained catch, or indirectly as bycatch). Key Customer Purpose: Gathering evidence on shark movements and survivability will allow qualitative assessments of the vulnerability of these stocks to fisheries (including as a bycatch). The information will also inform discussions on the benefits to stock conservation of size restrictions, MPA or seasonal closures, and other technical measures, such as gear modification. Specifically, the results will be used by ICES Working Group on Elasmobranch Fishes (WGEF), and the results will be used at international fisheries negotiations, such as TAC and quotas discussions on elasmobranchs; in negotiations with regional fishing management organisations and international conservation agreements such as CITES. The data will also provide evidence for evaluating the potential effectiveness of MPAs (e.g. understanding if key life stage areas can be identified), and forecasting the effects of reducing catch quotas without any control on by-catch. The data could also be used in discussions we fishermen to provide information on how their practices might need to change and what those changes might need to be. The benefits will enable Defra to assess how well national and international commitments to shark management are being met, and the potential risks to those commitments that current practices and policies pose. The new information will enable negotiations to be conducted with greater confidence and to ensure that new policies are founded on a good understanding of the resource and its exploitation.
United Kingdom