DNA tests of Greenland cod change history
Analyses found that there was a sharp increase in cod in local Greenland stock during the boom
New genetic analyses of fish samples from an old collection in Nuuk have revealed that the fish in Greenland’s ‘great cod boom’ in the 1960s did not come from Iceland but were as a result of a sharp increase in a local Greenland stock.
Up untill now it has been believed that the vast amount of cod caught during the boom, the total catch of which could reach 400,000 tonnes per year, was transported from Iceland by the ocean currents as eggs and larvae to the nursery areas in Greenland.
But researchers at DTU Aqua at the Technical University of Denmark (DTU) have now looked at genetic differences between cod from a variety of stock in terms of growth, sexual maturation and stress. The analyses have so far revealed that the cod in Greenland waters belong to at least four difference stocks, which breed independently of one another. Three of them spawn in Greenland waters and one in Icelandic waters.
Nina Overgaard Therkildsen, DTU Aqua, said: “One of the most exciting findings is that these samples, which were caught by west-coast fishermen when the fishing boomed between the 1930s and the 1950s, are very similar to the fish we find there today. This indicates, at least to a certain extent, that it was a sharp increase in a local Greenlandic stock, and not an inflow from the east or from Iceland, that gave rise to the fishery boom at the time.”
DTU Aqua researchers say they hope the findings will make it easier for the Parliament of Greenland to agree on how to protect Greenland cod, as well as change the way the cod fishery is administered.