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 northwestern 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 quantitative historical benthos data are available for the period prior to commencement 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 fished grounds. Attempts were made to calculate the short, medium, and long-term impact of the fishery on the benthos and surrounding environment. Direct (short-term) effects were not quantifiable at a heavily fished offshore site (75 m depth); however, some changes were visible in a less fished, shallow (35 m depth) site. Medium to long-term effects were more discernible at the offshore site. Only minor changes were observed at the inshore location, suggesting that it is fishing intensity pei se, rather than the direct impact from passage of the gear, that constitutes the major factor controlling long-term negative trends in the benthos of the Irish Sea Nephrops grounds. (C) 2000 International Council for the Exploration of thr Sea.