Blue whiting

Scientific: Micromesistius poutassou. English: Blue whiting, poutassou. Icelandic: Kolmunni. For more languages see the Marine Animal Dictionary.

Biology and distribution

The blue whiting is a rather small codfish, usually 22 to 30 cm long, but can reach up to 50 cm in length. It is unique among codfishes since it is purely an open ocean pelagic fish. It can be found all around Iceland but occurs only sporadically off the north and northwest coast. It is found in European waters from Murmansk in the north to the Mediterranean Sea in the south but also around the Faroe Islands, in Greenlandic waters and, in small amounts, off North America. A related species, Micromesistius australis, lives in the Southern hemisphere.

The blue whiting is a true international fish. It is uncertain if there exists a stock of pure Icelandic strain. Most of the fish in Icelandic waters probably originate from larvae drift from the main spawning grounds off the British Isles or by the migration of adults. The adult stock migrates all over the eastern North Atlantic, up to the Barents Sea and even to the Denmark Strait. Mature blue whiting is found in the open sea, most often near the surface or in mid water, but can also be found down to depths of 1,000 meters. Migrations are irregular and probably controlled by ocean currents and temperatures. The blue whiting is a species that is either there in plenty or completely absent. For example, in 2003 large amounts occurred in the offshore shrimp survey off the entire northern Icelandic shelf. But apart from that, the blue whiting has been virtually absent in these surveys.

The blue whiting feeds on a variety of pelagic organisms, small fishes, small squid, copepods and krill.

Some limited spawning seems to occur in Icelandic waters but the main spawning grounds are to the north and northwest of the British Isles, close to the bottom at depths of 250 to 450 metres., Spawning takes place in February to March in the main spawning grounds, but earlier in warmer waters to the south and later in colder waters to the north. Upon spawning, the fish migrate north to feed and are found in greatest quantities between Iceland and Norway.

The blue whiting grows rapidly during its first year, and reaches maturity at the age of 2 to 4 years. After that growth slows down. It can reach up to 20 years of age and at seven years old it is about 32 cm long.

Catch and fishing methods

Blue whiting is among the ten most fished species in the world. The stock is very large and primarily fished in the northeast Atlantic. Large-scale fishing of blue whiting was resumed in Iceland in 1998 after almost two decades of very little fishing effort. In the past few years, fishing has increased very significantly, and in 2003 Icelandic vessels fished over 500,000 tonnes. Recently, landings by Icelandic vessels have been about 300,000 tonnes while total landings from the stock have been close to 2 million tonnes.

Icelandic vessels fish chiefly within the Icelandic EEZ and in Faroese waters with pelagic trawl. Landings are seasonal. The season starts in March with the best fishing in May-July. Fishing is exclusively by pelagic trawl. Usually, the fisheries are rather clean but occasionally saithe and redfish are caught as bycatch.

Blue whiting is fished by Norway, the Faroe Islands, Iceland and the EU. Towards the end of 2005, these parties agreed on the allocation of fishing quotas and the total allowable catch. This agreement also involves a systematic lowering of the TAC in years to come, to reduce fishing mortality.

Stock status (from the Marine Research institute)

International landings of blue whiting (Micromesistius poutassou) in the Northeast-Atlantic in 2009 are estimated to be around 590.000 t. Icelandic landings were 120.000 t. Results of an acoustic survey in the spawning area west of the British Isles in spring 2010 showed at least 38% lower biomass than in 2009. The analytical assessment in 2009 indicates a steady decrease in the spawning stock since 2003 of about 48%. ICES will assess the stock in September and release its advice for 2011 in October 2010.

Processing and markets

More than 95% of the catch is reduced to fish meal. However, an increasing share is frozen at sea for human consumption. Half the export is to Norway where it is primarily used as feed in aquaculture.

Herring, capelin and blue whiting are the most valuable pelagic resources in Iceland. Blue whiting, however, belongs to the cod family and is low in lipids and light in colour, unlike the flesh of herring and capelin. Blue whiting is therefore well suited to processing but the raw material has a short storage life. When frozen at sea the blue whiting is therefore processed whole on board large freezer vessels.

References and further information

References: (Pálsson, 2005), (Jónsson & Pálsson, 2006).

For full citation and further information on the main species in general see this page

Hreiðar Þór Valtýsson, University of Akureyri