The stock structure is not totally clear; migrations are detected among the areas according to tagging experiments (Jakobsen and Olsen 1987, ICES 2010). The magnitude of migrations seems to differ among the areas studied due to the topography or distance, and climate systems strongly influence the inter-annual variability in the transport of early life stages (Homrum et al. 2013)(Myksvoll et al. 2021).

The Rockall population exhibited genetic differences from the other North Atlantic populations, while the Central Northeast Atlantic population shows high connectivity among the North Sea West and East, Faroes, Iceland, and the Norwegian coast (Myksvoll et al. 2021).

Four assessment units are considered within the NE Atlantic region for evaluation of the stock condition as well as for management purposes:
1 – Barents Sea (Subareas I and II, Northeast Arctic), mainly along the coast of Norway south to 62ºN (this profile). Haddock and cod are also targeted in this fishery.
2 – Icelandic waters (Division Va),
3 – North Sea, Skagerrak, west of Scotland, and the Rockall (Divisions IIIa, IV, and Subarea VI).
4 – Faroe Islands (Division Vb).