Growth characteristics and growth potential of the blue king crab Paralithodes platypus in the Sea of Japan

The blue king crab Paralithodes platypus (Brandt, 1851) is a widespread and abundant member of the family Lithodidae in the Pacific Ocean. However, its population size in the Sea of Japan is subject to strong fluctuations. Due to the low abundance of blue crab, its commercial fishery in the Sea of Japan has been prohibited since 2022. Therefore, the aim of the study was to evaluate the growth characteristics and growth potential of the blue king crab in the Sea of Japan relative to other aggregations of this species in the Sea of Okhotsk and the Bering Sea. The growth was studied according to the literature and our own data, which were collected on counting-trap surveys in the coastal regions of the Sea of Japan in 2011–2014. According to the Bertalanffy equation, male blue king crab in the Sea of Japan reach the carapace width CWinf = 193.5 mm, females – 162.1 mm. Comparison results of growth rate of the aggregation in the Sea of Japan showed significant differences with crabs off the Shantar Islands and eastern Sakhalin and did not note statistically significant differences in growth relative to aggregations in Shelikhov Bay and in the Bering Sea. Probably, first of all, such differences are the result of the complex influence of hydrological habitat conditions, food productivity of water areas, as well as competition, both interspecific and intraspecific.