What is blue fish

Fish lexicon: blue whiting (Micromesistius poutassou)

Blue whiting
(Micromesistius poutassou)


The blue whiting (Micromesistius poutassou) is a saltwater fish that is a maximum of approx. 50 cm long and weighs just under 1 kg. It is common in the north-east Atlantic from Morocco to Iceland and Spitzbergen, in parts of the Mediterranean and in the north-west Atlantic between Canada and Greenland. In English it is called "blue whiting".

Commercial blue whiting is mainly fished with swimming trawls in the south and west of the British Isles and Ireland.

Importance as food fish

Blue whiting (Micromesistius poutassou) is usually not marketed fresh but processed into fish fingers, in Russia and Norway mainly fish meal or oil.


The main characteristics of blue whiting:

  • the body of the blue whiting is elongated, streamlined and laterally flattened
  • the basic color of the upper half of the body is usually grayish-blue, towards the abdomen the color gradually becomes silvery-white
  • Sometimes there is a round black spot on the base of the pectoral fin of the blue whiting; there are no other special features
  • the sideline of the blue whiting runs almost in a straight line to the base of the caudal fin
  • its mouth is above - the blue whiting's lower jaw protrudes slightly and protrudes over the upper jaw. Its mouth is covered with sharp teeth
  • 3 clearly separated dorsal fins sit on the back of the blue whiting
  • the blue whiting has 2 anal fins, where the 2nd anal fin sits under the 3rd dorsal fin
  • the caudal fin of the blue whiting is notched
  • female blue whiting tend to grow larger than males
  • Rays: D (total) 0 / 24-28, A (total) 0 / 33-39


The blue whiting (Micromesistius poutassou) reaches a maximum length of approx. 50 cm, its average length is approx. 22 cm. The maximum published weight of a blue whiting is 830 grams, but it is likely to be a little heavier.

Maximum age

The blue whiting (Micromesistius poutassou) can live for a maximum of approx. 20 years.

Way of life, habitat, occurrence

Blue whiting (Micromesistius poutassou) is widespread in the north-east Atlantic from Morocco to Iceland and Svalbard, in parts of the Mediterranean and in the north-west Atlantic between Canada and Greenland.

The habitat of blue whiting is the open sea. There this schooling fish lives in water depths between 100 and 1,000 meters. As a rule, it is found on the continental embankment in water depths between 120-420 m. Since the blue whiting follows the migrations of its planktonic prey, it stays above the water bed during the day and near the water surface at night.


The blue whiting (Micromesistius poutassou) reaches sexual maturity at around 2-7 years. Spawning season is mostly from March to April in the west of the British Isles and Ireland.

During this time, the females of blue whiting spawn between 6,000 and 150,000 eggs in open water, depending on their size. The approx. 0.3 cm long fish larvae hatch after approx. 7 days (depending on the temperature). The growth of the young blue whiting is approx. 15-16 cm in the 1st year of life, in the 5th year of life it reaches a length of approx. 25-30 cm.


The blue whiting (Micromesistius poutassou) feeds mainly on crustaceans, cephalopods and small fish.

Copyrights to the text
This text is protected by copyright. Duplication, processing, distribution and any kind of exploitation outside the limits of copyright law require the written consent of WESO GmbH.
Image rights

Many of the images in our fish dictionary are protected by Creative Commons (CC for short) or other copyrights. Creative Commons is not the name of a single license. Rather, the various Creative Commons licenses vary widely. Further information on Creative Commons licenses can be found [here].

Information on GNU Free Documentation License (short: GFDL) can be found [here].

The copyrights and license rights for the images on this page are displayed when you click on the respective image or on "Show image rights".

All pictures were digitally processed by us and cropped in size.

Cookies (data protection)

We only save cookies that are technically necessary for the operation of our website. Cookies are only saved for the current session. No third party cookies or user tracking cookies are stored.

Youtube videos (data protection)

If this page contains videos and you click (open) a video, personal data (IP address) will be sent to the operator of the video portal (YouTube). It is therefore possible that the video provider saves your access and can analyze your behavior. However, this only happens when you open a video on this page.

Disclaimer of liability

All articles in our fish dictionary are for general information only and do not claim to be correct or complete. No liability is assumed for the completeness and correctness.

All pictures were digitally edited and cropped by us. More information under "Image rights".