Estimates of the abundance of mesopelagic fish off southern Norway and west of the British Isles 1971-1976. In: Flødevigen rapportserie no 1, 1986

Abstract

Mesopelagic fish were studied using 38 and 50 kHz echo sounders and electronic integrators on cruises covering the Norwegian Deep, Skagerrak, the slope north of the North Sea and west of the British Isles during 1971-1976. Samples of the fish were taken using comrnercial pelagic trawls. In Norwegian waters Maurolicus muelleri was the dominant species and the estimated stock size in the area covered ranged between 20 000 and 1 600 000 tonnes. No seasonal variation in abundance could be traced. West of the British Isles Notoscopelus kroeyeri seemed most important, followed by M. Muelleri. Estimated stock size ranged between about 0.3 to 13 million tonnes. All the stock size estimates are tentative, as the density coefficient used to convert echo abundance to fish biomass is not known for the species involved, and a coefficient worked out for another fish species had therefore to be used.