By Peter Bondo, Arctic Research Centre, Aarhus University

An international research team representing various areas such as fish taxonomy, trophic ecology, fisheries science, climatology, oceanography and ecological modeling is behind the new sensational study.

The group's results are based on ecological modeling and show that the warming of the Arctic makes it possible for a number of fish species from the North Atlantic and the North Pacific to pass through the Northwest and Northeast Passage. The interchange is a result of rising temperatures and increased productivity at high latitudes and will lead to the mixing of hitherto separated fish populations.

It is nearly three million years ago that the environmental conditions last allowed an extensive transfer of species. Back then it was mainly marine species from the Pacific Ocean, which spread to the Atlantic Ocean.

Transfers can have major consequences

Redistribution and transfer of species will significantly increase fish biodiversity in coastal areas around, for instance, Greenland and Svalbard, and it will cause major changes in the interactions among species.

The now published study predicts that some commercial species will expand their distribution in the far north and thereby potentially increase fish yields. But these fish stocks will also be included in new ecological relations under the influence of climate change. And it will lead to increased competition between existing and invading species.

Associate Professor Peter Grønkjær from Aarhus University took part in the study, and he believes that the interchange between the oceans potentially provides new fishing opportunities, but that it may have negative consequences for the original ecosystems.

"When the balance between species shifts, it means that the interaction between the individual species changes. Some native species will be out-competed by the newcomers, which in turn can cause changes in other parts of the ecosystem; a cascade effect that can spread to benthic invertebrates, birds and marine mammals. It is therefore essential to monitor the development in the fragile Arctic ecosystems," says Peter Grønkjær.

Past history has shown that such a transfer of species can have serious ecological consequences. For example, the opening of the Suez Canal in 1869 meant that the marine fauna from the Red Sea spread to the Mediterranean. The current Mediterranean fish community is consequently dominated by species from the Red Sea, which has had adverse ecological and economic effects on the Mediterranean biodiversity and fisheries industry.

The coming decades will therefore offer new challenges and opportunities for fishing in the North Atlantic and the North Pacific, which today accounts for nearly 40% of the global commercial fishing.

A fishing vessel leaving the harbour of Uummannaq, Western Greenland. Interchanges of fishes via Arctic passages with climate change are predicted to create new opportunities and challenges for commercial fisheries. Photo: Julius Nielsen, University of Copenhagen, Denmark.

The research vessel RV Sanna owned by the Greenland Institute of Natural Resources conducting fish survey in the Upernavik Fjord system in Northwest Greenland. Photo: Julius Nielsen, University of Copenhagen, Denmark.

Atlantic halibut, Hippoglossus hippoglossus, a species with potential for future transfer via the NE and NW Passages. Photo: Peter Rask Møller, University of Copenhagen, Denmark.

Atlantic herring, Clupea harengus, a species with potential for future transfer via the NE Passage. Photo: Peter Rask Møller, University of Copenhagen, Denmark.

Witch flounder, Glyptocephalus cynoglossus, a species with potential for future transfer via the NE Passage. Photo: Peter Rask Møller, University of Copenhagen, Denmark.

More information:

Contact two of the leading scientists behind the results for further information: Associate Professor Peter Grønkjær, Arctic Research Centre, Department of Bioscience, Aarhus University, and Senior Researcher Mary S. Wisz, DHI, (former employee of Arctic Research Centre, Department of Bioscience, Aarhus University).

Associate Professor Peter Grønkjær, Arctic Research Centre, Department of Bioscience, Aarhus University, Aarhus, Denmark, phone: +45 2338 2177, e-mail: peter.groenkjaer@bios.au.dk.

Senior Researcher Mary S. Wisz, DHI Department of Ecology and Environment, DHI, Agern Allé 5, Hørsholm, Denmark, phone: +45 3018 3157, e-mail: msw@dhigroup.com.