According the latest research, there is no genetic differentiation between the Atlantic herring populations of Icelandic and Norwegian waters (Pampoulie et al. 2015).
Image: "Whitehead, 1985 FAO Species Catalogue. Vol. 7. Clupeoid fishes of the world (suborder Clupeoidei). An annotated and illustrated catalogue of the herrings, sardines, pilchards, sprats, shads, anchovies and wolf-herrings" via FishBase