Species composition and biomass of fishes by the data of bottom trawls in the northwestern Japan Sea in 1978-1990

Abstract

State of the demersal fish community in the northwestern Japan Sea in the period 1978-1990 is considered on the data of bottom trawl surveys. Mean total biomass of the demersal fish in the USSR economic zone in those times is estimated as 1.106 . 10 6 t. The bulk of fish community was formed by the families Gadidae, Pleuronectidae, Clupeidae, Hexagrammidae, and Cottidae with summary portion 95.1 % by biomass and 84.8 % by number. The most abundant fish species were walleye pollock Theragra chalcogramma (44.8 % of the biomass), scale-eye plaice Acanthopsetta nadeshnyi (12.2 %), pacific herring Clupea pallasii (8.6 %), blackfin flounder Glyptocephalus stelleri (7.7 %), pacific cod Gadus macrocephalus (4.7 %), and arabesque greenling Pleurogrammus azonus (4.6 %), portions of other species didn’t exceed 3 %. The summary portion of flounders (23 species) was 28.0 %, by biomass. Scale-eye plaice dominated among them (on average 135.4 . 10 3 t), other mass flounders were the blackfin flounder (84.8 . 10 3 t), yellowstriped flounder Pseudopleuronectes herzensteini (29.0 . 10 3 t), and yellowfin sole Limanda aspera (13.2 . 10 3 t) though the latter species had dominated there in the 1930s.