A possible model approach to stock assessment of marine commercial invertebrates is discussed based on modeling of year-to-year dynamics for three functional groups (recruits, prerecruits, and commercial males). The model parameters are determined by joint solution of the tasks of optimal filtration and identification. As an example, this approach is used for assessment of the stock of king crab on the shelf of West Kamchatka. For this case, the data on actual catch are used obtained from reports of customs in Japan, Korea, USA, and China about the volume of crab products imported from Russia. The modeling confirms the conclusion from direct observations about rapid growth of the red king crab stock at West Kamchatka in recent years. Following to these results, the value of total allowable catch (TAC) can be substantially increased for this species. The officially recommended TAC of red king crab at West Kamchatka for 2016 is below of the 95 % confidence interval of the really possible catch. This value does not account the species stock recovery and hamper rational utilization of the valued natural resource.

Fecundity of northern shrimp Pandalus borealis is investigated for the first time on the data collected from the depth 200-400 m near the coast of West Kamchatka in 2013-2014. The absolute and relative individual fecundity are determined, their relationship with size and age of the shrimp is analyzed. The individual fertility of females changes in limits of 1395-4648 eggs, with average number in the laying 2799 ± 190 eggs. The maximum fecundity is noted for females at the age of 7+. Losses of eggs for the northern shrimp at the west coast of Kamchatka don’t exceed 12 %.