Warming of the Barents Sea Threatens Fish Stocks
A significant rise in temperatures in the Barents Sea is endangering the spawning grounds and food supply of key fish species. This is the conclusion of a new resource overview by the Norwegian Institute of Marine Research, presented in early February 2026 at the Arctic Frontiers conference in Tromsø.
According to the report, surface temperatures in Norwegian waters in recent years have been between 0.5 and 2.5 degrees above the previous average. The northern and eastern parts of the Barents Sea, as well as waters west and north of Svalbard, are particularly affected.
The director of the Institute of Marine Research, Nils Gunnar Kvamstø, emphasized during the presentation the growing importance of reliable data on fish stocks. In light of geopolitical tensions, ensuring food security is becoming increasingly important. At the same time, climate change and political developments are making sustainable management of marine resources more difficult.
Graphs presented by marine researcher Geir Huse show clear temperature changes over the past three decades. While the upper layers of water have warmed significantly, temperatures in deeper layers remain comparatively stable.
At the same time, scientists are observing a marked decline in fish stocks. Pelagic fish in particular, which live in open water, are losing biomass. Researchers see a key cause in the combination of rising temperatures and a decline in plankton, the primary food source for many fish species.
Arne Pedersen, chairman of the East Finnmark Fishermen’s Association, described the development as alarming. The plankton species Calanus, a key food source in the Arctic ecosystem, has declined significantly. “Even whales depend on this plankton,” says Pedersen. For many fish species that spawn in fjords, Calanus is crucial for the survival of juvenile fish.
Economically important stocks such as Arctic cod are also now under pressure, according to the institute. The stock has reached a critical level, mainly because too few young fish are replenishing the population. At the same time, in recent years, more cod has sometimes been caught than recommended.
In December 2025, Norway and Russia therefore agreed on the lowest cod quota since 1991.
Overall, fish stocks in waters around Norway have halved since 2013, according to the institute. At that time, the estimated total biomass was around 35 million tonnes. Today, it has reached its lowest level since the year 2000.
Pedersen is therefore calling for much stricter protection measures for spawning grounds. “In some fjords, fish can no longer spawn sufficiently,” he says. “If we want there to still be fish in the future, these areas must be able to recover.”
Heiner Kubny, PolarJournal
