An assessment of nets with a square mesh panel as a whiting conservation tool in the Irish Sea Nephrops fishery

Abstract

Despite increases in the minimum allowable mesh size in the Irish Sea Nephrops fishery the data presented here indicate that a large number of juvenile whiting are still being caught and discarded dead at sea. Preliminary flume tank studies were performed jointly with the Sea Fish Industry Authority (SFIA) in Hull. Observations indicated that the meshes in a panel of netting with square-shaped meshes inserted into the top of a trawl net remained open when the net was under tension, whereas the traditional diamond-shaped meshes tended to close. Trials at sea using the SOAFD (Scottish Office Agriculture and Fisheries Department) remote-controlled television vehicle (RCTV) confirmed that under tension the diamond-shaped meshes towards the end of the net closed during trawling whereas the square-shaped meshes of a panel inserted in this region remained open. Good escapement of small fish through the square mesh panel was filmed during trawling. Nephrops tended to scuttle along the bottom of the net and did not escape. Commercial fishing trials using a vessel rigged to pull two trawl nets simultaneously, one with a square mesh panel and one without, demonstrated significantly better whiting escapement from the net with the square panel than from the conventional all-diamond net. Results obtained from this investigation suggest that a panel of square-shaped mesh fitted to a Nephrops trawl could be an important whiting conservation tool.