Discard survival of coastal elasmobranchs in a small-scale fishery using acoustic telemetry

Abstract

The discard ban policy, which aims to reduce discards in all types of commercial fisheries by means of the landing obligation, is particularly challenging for the small-scale fishing fleet because of its multispecies nature and technical limitations. For this fleet, demonstrating high survival rates of discarded individuals may provide flexibility to accommodate to the discard ban. This study focused on a set of elasmobranch species targeted by the SSF in one of the most important fishing regions in Europe, i.e. Galicia (NW Spain). Using a fixed acoustic telemetry array and recapture data, we estimated short and long-term survival of a community of coastal elasmobranchs from family Scyliorhinidae (Scyliorhinus canicula, n = 15) and Rajidae (Raja undulata, n = 2; R. clavata, n = 10; R. brachyura, n = 3). Survival rates ranged between 70%/66% (short/long-term) in R. clavata and 100% in R. brachyura and R. undulata (100%/92% in S. canicula); with an overall long-term survival rate of 90/85%. Body size and time on board decreased the probability of survival in the R. clavata. This is the first study that estimates discard survival of coastal elasmobranch in the Galician small-scale fishery using acoustic telemetry techniques. Our results are critical to support the application of survival exemption of discards in SSF, and for the design of management plans for elasmobranch species and their habitats