Scientists on a frozen icebreaker make a surprising discovery in the heart of the Arctic Ocean

In cold waters, researchers have found cod and squid, which can apparently thrive much farther north than previously thought.

The Polarstern is a German research vessel and icebreaker that conducts important research in the coldest regions of the world. Among other things, the icebreaker froze in the Arctic Ocean, allowing scientists on board to subject their immediate surroundings to a thorough inspection. It leads to a surprising discovery. Because in deep water in the heart of the Arctic Ocean, they unexpectedly found fish and squid.

Peach
First, scientists aboard the Polarstern discovered that some small fish swim at a depth of around 200 to 600 meters in the so-called Amundsen basin. But they were even more surprised when they suddenly caught four bigger fish 350 to 400 meters deep. Additionally, three of the four fish turned out to be cod; a predatory species which, so far as was thought, has not been found so far north. Moreover, cod is a typical coastal fish. The researchers therefore did not expect to find this fish in an ocean basin four kilometers deep more than 500 kilometers offshore.

Cod
Laboratory analyzes show that the discovered cod have been living in the arid waters of the Arctic for six years. And this when it was thought that cod are more comfortable at a water temperature between 0 and 20 degrees Celsius. However, research shows that the fish can also thrive in colder temperatures and have apparently found a pleasant home in the Arctic Ocean. “A small number of specimens seem to be able to find enough food to stay healthy for a long time,” said researcher Pauline Snoeijs Leijonmalm.

Calamari
In addition to cod, the researchers discovered another remarkable species using an offshore camera deployed under the pack ice. For example, in the deep waters in the heart of the Arctic Ocean there are also squids of the family Gonatidae for swimming. This also means that this species is found much farther north than previously thought.

Squid spotted using an underwater camera in the heart of the Arctic Ocean. Image: EFICA Consortium

According to the researchers, these surprising findings have put some pieces of the puzzle back together. “The presence of small and even larger fish could explain why seals, walruses and polar bears can be found in the Arctic,” says biologist Hauke ​​Flores. “Although the fish and mammals are there in small numbers, they are there.” The immigration of large fish from the Atlantic thus contributes to the pelagic food web of the central Arctic ecosystem, possibly representing an important food source for mammals living in the Far North.

protection
Snoeijs Leijonmalm emphasizes that it is of great importance that this fragile but fully functioning ecosystem receives strong international protection. Global warming is hitting the Arctic harder than the rest of the world. And this means that in a few decades not only icebreakers, but also ordinary ships will be able to navigate the Arctic Ocean. However, based on the new findings, the researchers conclude that today and in the future, there are too few fish swimming in the waters to be able to catch them. “That was to be expected,” says Snoeijs Leijonmalm. “The Arctic Ocean is known for its low nutrient content and very low biological productivity. Even with more Atlantic fish swimming in the waters, the capacity of the Arctic Ocean ecosystem to support larger fish stocks is undoubtedly quite limited.

As a precautionary measure, Canada, China, Greenland, Iceland, Japan, Norway, Russia, South Korea, the United States and the European Union have already negotiated an agreement to prevent fishing on the unregulated high seas in the central Arctic Ocean. “This agreement prohibits commercial fishing for at least 16 years and puts ‘science first’,” said Snoeijs Leijonmalm. “A wise political decision and a good start for full protection.”