The researchers had not expected this: during the “Mosaic” expedition they came across cod in the middle of the central Arctic. And the fish were also up to 70 centimeters in size.
Bremerhaven – Cod and squid can live much further north than previously assumed: During the “Mosaic” expedition with the research ship “Polarstern”, scientists discovered individual large specimens of these sea creatures in the Central Arctic.
The consortium “Efica” (European Fisheries Inventory in the Central Arctic Ocean) now describes the find in the journal “Science Advances”. For a long time, science assumed that there were no fish in the central Arctic Ocean – and if there were, then only very small ones, said Hauke Flores, a biologist at the Alfred Wegener Institute (AWI) in Bremerhaven.
During the expedition, which lasted from 2019 to 2020, the researchers caught, among other things, three specimens of Atlantic cod, which is actually an coastal fish. A fish measured 67.5 centimeters. “It was a total surprise,” Flores said. The laboratory showed that the fish came from Norwegian spawning grounds and were up to six years old.
Few nutrients in Central Arctic
“A small number of individuals seem to be able to find enough food to survive over long periods of time,” said Pauline Snoeijs Leijonmalm, coordinator of the EFICA consortium and professor of marine ecology at Stockholm University. With the help of a deep-sea camera, squid and sardines were also discovered during the expedition. “The availability of small and even some larger fish in the Atlantic water layer could explain why seals, walruses and polar bears can be found even at the North Pole,” Flores said.
At the same time, the researchers emphasize that the low nutrient content in the Central Arctic prevents a larger population of fish. However, changes are possible due to climate change, while at the same time navigating an ice-free Central Arctic in summer is only a matter of decades.
As a precaution, an international agreement came into force in 2021, which was signed by the USA, Canada, Russia and the European Union, among others. “This agreement prevents any commercial fishing for at least 16 years,” said Pauline Snoeijs Leijonmalm. Science therefore has time to continue researching the fish stocks. This is a “good start on the way to comprehensive protection,” said the scientist. dpa
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