The mackerel has its breeding grounds from the Bay of Biscay to the North Sea. But now it has been documented that mackerel also grow up north of the Nordkapp.
– It is not because the sea has become warmer in the north, but it is connected to the explosive growth in the mackerel population between 2006 and 2014.
This is what researcher Leif Nøttestad says in a message from Institute of Marine Research.
Threefold
The stock almost tripled in less than ten years, and from 2006 to 2014 the mackerel stock in the North-East Atlantic increased from 2.2 to 5.9 million tonnes, according to the researchers’ calculations.
– Many people don’t understand that I bother
Almost a triple, that is.
Warmer seas in the same period were probably a reason for good conditions and population growth – but not the actual reason for moving north, according to the researchers.
– It was their own need for space with an internal fight for food that meant that the mackerel had to expand its grazing area in a big way, says Nøttestad.
The adult mackerel subjugated the entire Norwegian coast and the Norwegian Sea, as far north as Svalbard.
– In such a climate, the mackerel is a very flexible fish. It thrives in anything between four and twenty degrees. But like everyone else, it needs food for survival and growth, says the researcher.
A new player in the ecosystem
The mackerel’s northern expansion broke new records last autumn. Then the researchers found mackerel fry at the North Cape.
PIR: Also young mackerel – or pir – can now be found in northern Norway. It indicates that the mackerel grows up there. Photo: Åse Husebø / Institute of Marine Research
Young mackerel establishing themselves in new places could in theory mean that there will be more competition for food – especially for herring and other mackerel.
– We know that each mackerel lost weight in the same period as the stock increased, and that there was probably less zooplankton in the sea in the same period.
– But it is difficult to establish whether one has led to the other, says Nøttestad.
