The young of the northern Atka mackerel Pleurogrammus monopterygius in the epipelagic zone over deep-sea areas of the northern Pacific Ocean

摘要

On the basis of materials of integrated cruises of the TINRO-Center performed in the northern part of the Pacific Ocean between 1984 and 1996 and relevant literature, some aspects of the biology of the northern Atka mackerel Pleurogrammus monopterygius in the pelagic period of its life are considered. Data are presented on the distribution, migration, and numbers of juveniles in the epipelagic zone of different regions, as well as on their biological state and feeding. It is supposed that dependingon temperature conditions at the spawning grounds, the incubation period may be considerably prolonged; as a result, in some areas of the western pan of the reproductive area of the species, mass larval hatching may occur not only in autumn, but in spring of the next year. The duration of the feeding period of fingerlings in the epipelagic zone depends on the time of larval hatching and comprises 4-5 to 9-10 months. Within this period, they reach the length of 15-22 cm. A current increase in the numbers of the species in the northwestern part of the Pacific Ocean is related to the emergence of two strong year-classes of 1992 and 1993.