The dynamics of the abundance of the walleye pollock Theragra chalcogramma (Pallas, 1814) (gadiformes: gadidae) in the Sea of Japan

Abstract

The biomass of the walleye pollock (Theragra chalcogramma) stock in waters of Primorskii krai, Sea of Japan, during the 1976–2015 observation period ranged from 48000 to 373000 tons; their number ranged from 99 to 1115 million fish. Four very strong year-classes born in 1975, 1981, 1997, and 2006 have been identified. It has been shown that the duration of the sexual-maturity period is determined by the periodicity of the dynamics of the year-class strength close to the 9-year cycle. According to the results of numerical modeling, an increase in the walleye pollock stock in Primorye is expected from 2017 to 2020.