ICES CM 2001 / N : 06 SURVIVAL OF LESSER SPOTTED DOGFISH ( Scyliorhinus canicula , L . ) DISCARDED BY TRAWLERS

Discards of up to 35% represent a significant percentage of the catches in the trawl fishery. The estimated average annual dogfish catch in ICES area VIIIc is approximately 1,500 tn, from which 80% is discarded. Different experiments have been carried out in order to estimate the survival rate of the lesser spotted dogfish caught by trawlers in the Cantabrian Sea (North of Spain). Survival estimates based on tagging surveys have provided a mean value of 90% while estimates based on commercial trawlers gave 78%. No significant differences were found between males and females, and with the currently available data there was no strong relationship between survival rate and depth, sorting time or haul duration. Also, survival rate was not dependent on the length. The survival rate was estimated to be close to 0.42 based on length distributions from the total catch mortality (Z) caused by trawlers.