Knut Korsbrekke is one of the scientists who are out on the skreitokt with the vessel “Johan Hjort” in the Lofoten islands in these days.
This is one of several raids that the researchers make in the course of a year. The data they collect says a lot about the state of the stocks of fish in the sea.
When the NRK talk with Korsbrekke Monday, reports the including about 25 per cent less fish in the Vestfjorden compared with the previous year. The same for Værøy and Røst.
Measurements show that there are more fish this year than two years ago.
however, It is not this that is the great “snakkisen” on board. Korsbrekke tells that they got a real surprise in the Vestfjord.
At the end of march they observed namely skreiflo unlike anything they have seen before.
dollar value on the six billion
A skreiflo is an aggregate of gytende cod from the Barents sea. On the sonar, as you see the photo of the top in this case, ses fish as red spots.
the Phenomenon occurs every year. But never have they seen anything like this.
What is special is that the fish have been close to the land, and very concentrated, ” explains Korsbrekke, who is the cruise leader on board.
the Fish benefits usually over a larger area. But here is the density of the fish “quite extreme”, says the researcher.
– This is the highest number of fish per square kilometer, the researchers has ever seen.
On havforskningas Facebook page there is an image of what huge amounts of fish there are to talk about:
on board the Johan Hjort is released skreifangsten in a bucket on the deck before it is measured in the laboratory. This catch is around one ton of fish.
Photo: Knut Korsbrekke / Imr
“Between fifty and sixty thousand tons of fish on an area that is two to three square kilometers means seven million fish with an average weight of around eight pounds. Should this cod be sold in the shop for a hundred crowns per kilogram, gives it a dollar value on six billion”.
Unique experience
Why fish flock together so, have not the scientists no good answer.
But Korsbrekke says that cod is a social being.
Researcher Knut Korsbrekke is the cruise leader on the vessel “Johan Hjort”.
Photo: Martin Steinholt / NRK
– The stock sound during the spawning period, especially the males. How the social relationship is in such a huge concentration of spawning fish, we can’t fathom. It must be very special.
When the capelin and herring gather in large shoals, one can get enormous density of fish in a small space. But that this happens for large cod, is especially.
– This was a unique experience. It was fantastic to see, ” says Korsbrekke.
Important in forvaltningsarbeidet
When the scientists look down in the sea, so it is sonar that is used.
This gives a hint of how it looks under the sea.
When the cruise is over, the data are studied in more detail. Then you’ll also be able to say something about how much fish it is of the various årsklassene.
the Results from the surveys is important for researchers to advise on how Norway should manage the various fish stocks, one can read on the websites of The institute of marine research.
