The post-peak-yield gill-net fishery for spurdog Squalus acanthias L. in Western Ireland

Abstract

A gill net fishery, directed on Spurdog, expanded rapidly on the western coast of Ireland in the 1980s and quickly collapsed, the fishermen moving offshore in pursuit of smaller individuals. Catch per effort and landing data in the gill net fishery are used to estimate the size of the mature and maturing component of the south western "stock" which is within a range of 3,700 tonnes (landed) and 5,700 (calculated). An appraisal of the post-peak-yield landings reveals that the average individual weight declined from those of peak landings, in males by 9.5% and females 32.0%, and the percentage of females in them declined from 75 to 19%. The majority of the later catches were immatures whereas the peak-yield catches were mainly mature and maturing females. The average age of females was reduced from 19 to 16 years - 18 to 17 years in the case of males - and later captures were a shorter length at age. The fate of the depleted stock is not known and the possibility of its locus having moved elsewhere cannot be discounted.