The population structure of North Pacific pollock is complex and scientific understanding is evolving. In Russia, West Bering Sea Karaginsky, West Bering Sea Chukotsky, Sea of Okhotsk, and Sea of Japan pollock stocks are considered reproductively isolated from one another, albeit with some inter-migration between them, and are addressed separately from one another by the Russian authorities for purposes of stock assessment (Kotenev and Glubokov 2007); (Federal Fisheries Agency, Kamchatka Branch 2020). Russian authorities also recognize that there are fish that originate in the Japanese EEZ harvested in Russian waters (i.e., a separate Japanese Pacific stock) (Ovsyannikova 2012).

Within these groupings, the degree of differentiation among various populations is nuanced. Complications in elucidating pollock population structure include life histories that entail different habitats for spawning, overwintering, and feeding; larval drift from one region to another; and different population dynamics at low and high abundance (Kotenev and Glubokov 2007); (Grant et al. 2010).

This profile covers the East Kamchatka assessment and management unit, which includes the Petropavlovsk-Commander subzone (61.02.2 in this map) and North-Kuril zone (61.03). A separate assessment unit is considered in the South Kuril Islands.