ICES working group (WKNSCodID) met in 2020 (ICES 2020) and concluded that North Sea cod appear to be isolated from the cod population on the Faroe Plateau (Subdivision 5.b.1) and Norwegian Coastal Cod (subareas 1–2). Significant and persistent patterns of genetic variation indicate reproductively isolated populations of Viking cod and Dogger cod that have some spatial overlap and mixing after spawning. The Skagerrak and northern Kattegat appear to be a nursing ground for Viking and Dogger cod, with most cod in the Skagerrak being Viking cod. These genetically different groups have different rates of maturity and growth. Trends in biomass and recruitment are strongly correlated among subareas of the North Sea, but subarea trends diverged in the last decade, with no apparent rebuilding in the southern North Sea. The common trends in biomass and recruitment among subareas suggest that there is some mixing of populations after spawning in some areas of the North Sea, and common environmental factors throughout the region. A benchmark was conducted in 2023, which combined the former North Sea (cod.27.47d20) and West of Scotland  (cod.27.6a) cod stocks (ICES 2023). The three substocks are assessed jointly in a framework (multistock SAM) that explicitly models the individual dynamics of each substock (ICES 2024).

Each of the three sub-stocks has its own quotas, reference points, and stock status, but their evaluations are combined here for this profile.

This profile is for cod in North Sea, eastern English Channel, and Skagerrak (Subarea 4 Division 7.d and subdivision 20).