A Preliminary Survey of Benthos from theNephrops norvegicusMud Grounds in the North-western Irish Sea

A preliminary survey of benthic infauna from an extensive basin of soft mud in the Irish Sea was carried out in 1992. A total of 110 taxa were recorded of which polychaete worms (Phylum Annelida) constituted 77•8% of all taxa recorded. Hierarchical classification and detrended correspondence analysis divided the area studied into five regions which could be correlated to the differences in superficial sediments and depth across the basin. Although much of the fauna was ubiquitous, a change in trophic structure was observed, with tubiculous polychaetes becoming progressively less common in deeper softer sediment areas where surface and non-selective deposit-feeding taxa predominated.