A COMPARISON OF THE DEEP-WATER DEMERSAL FISH ASSEMBLAGES OF THE ROCKALL TROUGH AND PORCUPINE SEABIGHT, EASTERN NORTH-ATLANTIC - CONTINENTAL-SLOPE TO RISE

Fishery surveys of the continental slope to the west of the British Is les have shown quite marked differences between areas in both the prop ortion and abundance of marketable or potentially marketable species. In general, the northern slopes lying to the west of Scotland were con sidered to have a greater potential for exploitation than the southern slopes off Ireland. Subsequent detailed studies of a northern (Rockal l Trough) and a southern slope area (Porcupine Seabight) sampled the d emersal fish fauna using a Granton trawl fished on paired warps to dep ths of 1200 m: and a semi-balloon trawl fished on a single warp to dep ths of about 3000 m. The Granton trawl catches differed significantly between the two areas, especially at the greatest depths fished. The s emi-balloon trawl catches did not differ between the areas. This slowe r trawl was poor at catching large, mobile species and efficient in th e capture of the deep-water eel Synaphobranchus kaupi. This eel was nu merically dominant over the mid to lower slope and probably accounts f or much of the similarity between areas at these depths. (C) 1996 The Fisheries Society of the British Isles