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Atlantic mackerel (Scomber scombrus)

01.11.2012 // Since 1999, the fishery was regulated according to agreements between the Faroe Islands, EU and Norway. However, since 2009, there has been no coastal state agreement on management and allocation of mackerel.

Failing a coastal state agreement, Norway and EU have had annual bilateral agreements on the management of the Northeast Atlantic mackerel since 2009. The Faroe Islands and Iceland have set unilateral quotas for their mackerel fishery.

About the fishery

The main fishing nations are historically EU, Faroe Islands, Russia and Norway. Furthermore, considerable amounts of mackerel have been taken in the Icelandic zone in recent years through an initially unregulated fishery. In 2011 small catches of mackerel were for the first time reported in the Greenlandic EEZ. Norway and to some extent Scotland take most of the catches by purse seiners while the other nations mainly apply pelagic trawl. The Norwegian fishery is predominantly carried out in September-November, and the main parts of the catches are taken in the northern part of the North Sea. 

The stock has been measured since 1972. During this period the catches have been assumed to fluctuate between 360 000 and 930 000 tonnes. The main catches are taken in the North Sea, The Norwegian Sea, west of UK and Ireland, south of Ireland, in the Channel and in the southern area. 

Management and technical regulations of the fishery

Scientific analyses in 2008 provided new estimates of several reference points for mackerel, including an increased precautionary approach fishing mortality (Fpa) from 0.17 to 0.23. In October 2008 Norway, EU and the Faroe Islands agreed to implement a new long term management plan, which shall limit fishing to an amount consistent with a fishing mortality rate (F) between 0.20 and 0.22, when SSB is above 2,200,000 tonnes. If SSB is lower than 2,200,000 tonnes, F should be reduced progressively. ICES concluded that the plan is precautionary under the assumption that the TAC equals the total removals from the stock. 

The spawning stock biomass (SSB) has increased since 2002, and in 2009 the International Council for the Exploration of the Sea (ICES) classified the stock as having full reproductive capacity. However, the mackerel stock is at present harvested at increased risk because the total catches are exceeding the recommended TAC and the precautionary levels. The 2005 and 2006 year class are the strongest recorded, while the subsequent year classes have shown closer to normal variability around the long term average. The SSB estimate is sensitive to the egg survey estimates. The egg surveys are only performed every third year. Catch statistics are an important input parameter in the stock assessment. Earlier analyses demonstrated that the unaccounted mortality due to slippage and discards is significantly higher than that officially reported. Several measures have been adopted to improve control, and the problem of unreported catches has decreased in recent years.

Ecosystem/Biology

Mackerel is a pelagic and fast swimming fish species. It is distributed in the Northeast Atlantic from the Northwestern part of Africa north to the Barents Sea, and westwards in the Norwegian Sea to Iceland and Jan Mayen. Mackerel also enters the Baltic Sea, and furthermore exists in the Mediterranean Sea and Black Sea.

Mackerel is a typical zooplankton feeder on the abundant copepod Calanus finmarchicus, but also feed on molluscs (Limacina retroversa) and small fish that can be swallowed, mainly sandeel, herring and sprat. 

Mackerel in European waters are managed as one stock, Northeast Atlantic mackerel, which exists of three spawning components: North Sea mackerel which spawn in the central part of the North Sea and Skagerrak (May-July); western mackerel which spawn west of Ireland and the British Isles (May-July); and southern mackerel which spawn in Spanish and Portuguese waters (February-May).

After spawning the western and southern mackerel migrate to the Norwegian Sea, and after a while also migrate to the North Sea and Skagerrak where the mackerel mix with the North Sea mackerel. The southern and western components remain here the whole autumn and further during winter (December-May), until they migrate back to their respective spawning areas.

Catch and survey data from recent years indicate that the stock has expanded north-westwards during spawning and the summer feeding migration. This distributional change is likely a reflection of increased stock size coupled with changes in the physical environment and the zooplankton concentration and distribution.

 

 


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