Sexual dimorphism and morphologic differences in blue whiting (Micromesistius poutassou)

Blue whiting is distributed over a vast area in the Northeast Atlantic from the Barents Sea to the Mediterranean. Within this area spawning has been observed in the Mediterranean, in the Bay of Biscay, west of the British Isles and south of Ireland. North of the Shetland-Faroe-Iiceland Ridge, apart from single observations, no spawning has been observed. The area west of the British Isles is a major spawning area whereto fish from the Norwegian Sea migrate to spawn.

It is however difficult to concieve that all blue whiting, which are found in the Norwegian Sea and in the Barents Sea during summer and autumn belong to the same spawning stock. In that context morphometric measurements and meristic counts on blue whiting were performed during some surveys with "G.O. Sars" to the Norwegian Sea and to the spawning area west of the British Isles.