Rasmus Berg Hedeholm and Greenland map (Photo Credit: TUBS CC BY-SA 3.0 /FIS)

Cod thought to be Icelandic could have been 'made in Greenland': study

It turns out that the fish in Greenland’s great cod boom in the 1960s came from Greenland itself and not from Iceland as experts had believed.

It was thought that the enormous amount of cod in the country’s territorial waters during the boom had been carried over from Iceland by ocean currents as eggs and larvae.

”Since the 1930s, biologists have tagged more than 100,000 Greenland cod. When these cod are recaptured, the data can be used to map their migration route. Many fish from the great year classes have been recovered near Iceland, which has been taken as an indication that the fish swam back to Iceland to spawn,” explained Rasmus Berg Hedeholm, a biologist at the Greenland Institute of Natural Resources in Nuuk.

Fish geneticists at DTU Aqua at the Technical University of Denmark are now conducting DNA analyses as part of a research project about Greenland cod from a climate perspective at the Greenland Climate Research Centre (GCRC). They examined genetic differences between cod from multiple stocks in terms of factors including growth, sexual maturation and stress.

They believe that the cod in Greenland waters belong to at least four different stocks, each of which spawns individually -- three in Greenland and one in Iceland.

”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,” said postdoctoral fellow Nina Overgaard Therkildsen of DTU Aqua. “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.”

This knowledge is useful for something like assessing the conditions required for a new and robust cod population to return to Greenland, and if it is confirmed that the stocks from the 1960s were actually “made in Greenland,” it might be easier to reach an agreement on how to protect today’s stocks.

The inshore stock has been rising in recent years and the International Council for the Exploration of the Sea (ICES) recommended a 2013 quota of 8,000 tonnes, which the Parliament of Greenland has increased to 15,000 tonnes.

By Natalia Real
[email protected]
www.seafood.media

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