The deep water fisheries of the Rockall trough: some insights gleaned from Irish survey data

Abstract

The Fisheries Research Centre (FRC) has conducted trawl and longline surveys in the Rockall Trough since 1993, fishing a total of 223 stations over the depth range 201 to 4,945m. Trawls produced greater species diversity and higher discard rates than longlines, which selected larger squalifurm sharks. In 1997, limited selectivity work, based on ten comparative tows, showed that the size range of roundnose grenadier (Coryphaenoides rupestris) caught using a commercial trawl (llOmm), with and without a small mesh end liner (30mm), were similar. This indicates that mesh size, because of poor selectivity and perceived low survival rates of escapees, may not be a useful management tool in the regulation of the trawl fishery.