Sampling surveys for deep-water demersal fish in 1993

Abstract

Potential for new developments in deep water fishing have been identified by two sampling surveys carried out in April and September 1993, in the deep waters off the west coast of Ireland and Scotland. The primary objective of the two surveys was to secure samples of a variety of potentially commercial deep water fish species in order to examine aspects of their age, growth, reproduction and diet. These data will be essential in formulating management plans for the expanding deep water fisheries in the area. The surveys were conducted on a chartered fishing vessel using a commercial otter trawl, fitted with a small mesh cod-end liner. Fishing activity concentrated on the depth range 400m-1200m and a total of 81 trawling operations were carried out, of which 75 produced fish catches with limited gear damage. Fifteen species of cartilaginous and 50 species of teleost fish were recorded from the catches. These include the roundnose grenadier Coryphaenoides rupestris, black scabbard Aphanopus carbo, greater forkbeard Phycis blennoides, blue-mouth rockfish Helicolenus dactylopterus and Baird's smooth-head Alepocephalus bairdii. Length, weight, sex, maturity and catch data together with samples of otoliths, gonads and stomachs were secured. In general terms, the fishing ground off the north west of Ireland and west of Scotland caused little problems with gear damage and yielded good catches of deep water species. The two surveys have shown the areas have potential for commercial deep water fishing but the development of this fishery in the area will be contingent on the establishment of suitable markets. This initial report documents the surveys and presents some preliminary results. The data gathered from these surveys are currently under analysis at the FRC and the results will be published in the scientific literature.