Long- and short-term consequences of a Nephrops trawl fishery on the benthos and environment of the Irish Sea

Short-term effects of fishing on benthos from a mud patch in the northweste rn part of the Irish Sea were investigated in 1994-1996 by means of samples taken both before and shortly after (ca. 24 h) fishing activity. No quanti tative historical benthos data are available for the period prior to commen cement of the fishery, although limited qualitative data exist. Therefore, studies of medium to long-term effects involved sampling the fauna of areas around wrecks (i.e., unfished pseudo-control sites) for comparison with fi shed grounds. Attempts were made to calculate the short, medium, and long-t erm impact of the fishery on the benthos and surrounding environment. Direc t (short-term) effects were not quantifiable at a heavily fished offshore s ite (75 m depth); however, some changes were visible in a less fished, shal low (35 m depth) site. Medium to long-term effects were more discernible at the offshore site. Only minor changes were observed at the inshore locatio n, suggesting that it is fishing intensity pei se, rather than the direct i mpact from passage of the gear, that constitutes the major factor controlli ng long-term negative trends in the benthos of the Irish Sea Nephrops groun ds. (C) 2000 International Council for the Exploration of thr Sea.