The development of a new gillnet fishery for anglerfish (Lophius piscatorius) in Norwegian waters

Abstract

In autumn 1992 a direct gillnet fishery for anglerfish (Lophius piscatorius) started on the continental shelf off the northwestern coast of Norway. The anglerfish had previously only been taken as bycatch in trawls and gillnets. The annual catches increased from 880 tons in 1991 to 4,447 tons in 1993, and then decreased to 2,621 tons in 1994. Studies on the fishery started in november 1992. Monthly sampling was conducted from commercial catches in 1993 and 1994 , for length and weight analysis. Age was determined by otolith- and first dorsal fin ray readings. Estimates of catch per unit effort were based on information from 5 commercial vessels. In 1994, the sex ratios and gonad development were analysed. In 1993 the average size ofthe anglerfish was 12.1 kg (n=706) decreasing to 11.2 kg (n=615) in 1994, all catches from gillnets of 360 mm stretched mesh size. In 1994 the average size of the fish from 300 mm mesh size was 7.8 kg (n=433). The difference in average length and weight between the two mesh sizes, corresponds to approximately 1 year of growth. Adult females are larger than males. 360 mm gillnets caught more females than the 300 mm gillnets, respectively 81 % and 62 %. In 1992, CPUE was 1-2 kg with maximum 3-4 kg per day per net. The catch rates started decreasing during summer 1993 and was estimated to 0.3 kg per net per day in autumn 1994.