Occurrence of Norway Pout, Trisopterus Esmarki (Nilsson) and Blue Whiting, Micromesistius Poutassou (Risso), in the Western English Channel off Plymouth

Abstract

The small gadoid Trisopterus minutus (L.) is one of the most abundant demersal fishes on the Plymouth trawling grounds, though it is not retained in any number by the meshes of commercial trawls (Marine Biological Association, 1957). Correspondingly, the post-larval stages can be very numerous in the routine macroplankton collections at the Eddystone (Russell, 1973). However, in 1971 and 1972 T. minutus was accompanied by a few post-larvae of two other small gadoids, T. esmarki and Micromesistius poutassou (Russell, 1973,1976), and it was suggested that these might have drifted into the Plymouth region from spawning grounds farther to the west. A recent southerly shift in the main spawning region along the edge of the continental shelf was noted by Bainbridge & Cooper (1973), and Coombs (1975) has reported corresponding shifts in deep water species.