Structure of the deep demersal fish fauna off Newfoundland

Abstract

Bottom trawls on the Newfoundland continental slope at depths from 204 to 2325 m near Carson Submarine Canyon (45"30fN, 48"40'W) took 4222 individuals in 39 species of demersal fishes. The fauna was not strictly zoned, but showed a fairly uniform addition of species with increasing depth over the entire range. Lack of zonation may be related to the high production of the area, and its absence here casts doubt on the idea that fauna1 regions continuously rim the ocean basins. Dominant species were mainly macrourids (Macrourus berglax, Coryphaenoides rupestris, Nezumia bairdii, Nematonurus armatus) and the morid Antimora rostrata. Overall abundance, biomass, and diversity were least at the greatest depths. Only A. rostrata and C. rupestris were bigger-deeper; juveniles of both are abundant in shallow northern waters. The proportion of species belong~ng to shallow-water groups decreases steadily with depth, a pattern also seen in other data and implying ongoing invasion of the deep sea by fishes from the continental shelves.