Net selectivity studies in the Northern Ireland Nephrops fishery

The effect on catch composition of a large mesh lifter net fitted to a trawl cod-end was investigated in the Northern Ireland Nephrops fishery in the north west Irish Sea (ICES area Vila). Two experiments were conducted using chartered commercial fishing vessels. In the first experiment, parallel hauls showed there to be no significant difference in the Ncphrops size distribution caught by nets with and without a lifter net. The result of the second experiment, in which the cod-end was fitted with a small mesh cover to retain escaping Nephrops, did not suggest that the cod-end meshes were blinded by the lifter. Field data are contrasted with those from theoretical studies of mesh obstruction.