New Genetic Insights into Polar Cod Reveal Climate Change Risks for Arctic Ecosystems Published 10.03.2025
Leuven, January 2025 – The polar cod, one of the key fish species in the Arctic Ocean, is facing significant challenges due to climate change. As a primary food source for many Arctic mammals and birds, polar cod plays a critical role in maintaining the delicate balance of the Arctic ecosystem. A new study conducted by the University of Leuven (KU Leuven), in collaboration with international research partners, provides groundbreaking insights into the genetic diversity of this species – and highlights the potential consequences of global warming.
The research team, comprising scientists from Belgium, Canada, Greenland, Iceland, Norway, the United States, Russia, Sweden, and Germany, employed state-of-the-art genetic analysis methods to investigate the population structure of polar cod. A key feature of the study is the inclusion of extensive samples from the central Arctic, collected during expeditions with various research icebreakers.
“Finding polar cod under the sea ice seems impossible. Thanks to the efforts of many colleagues and the crews of Polarstern and Sikuliaq operating the Surface and Under-Ice Trawl, and sometimes using bare hands, we were so lucky to assemble a unique sample collection from this harsh environment.” tells Hauke Flores.
The findings reveal that there are at least three genetically distinct populations of polar cod in the Arctic Ocean. One population inhabits the Beaufort and Chukchi Seas along the northern coasts of Canada, the USA, and Russia; another is found in West Greenland; and a third population spans the transpolar sea ice drift from the Siberian coast to the central Arctic Ocean, the European Arctic, and Iceland. Historically, sea ice drift and ocean currents have facilitated genetic exchange between these populations, a key mechanism supporting the species’ adaptability.
“Our results show how the genetic diversity of polar cod is driven by the environment in the different regions of the Arctic Ocean. Sea-ice drift is important for enabling genetic exchange, which is crucial to strengthen the resilience against change in all populations.” says Filip Volkaert.
However, this natural connectivity is under threat. The retreat of sea ice and changing ocean conditions could significantly reduce genetic exchange and weaken the survival prospects of polar cod populations. This, in turn, could impair the species’ resilience to the impacts of climate change and destabilize Arctic ecosystems as a whole.
“Our findings highlight the urgent need to preserve the adaptive potential of polar cod and other Arctic species,” said a spokesperson for the KU Leuven research team. “The study provides valuable insights that can serve as a foundation for conservation and management strategies tailored to the unique conditions of the Arctic.”
The rapid changes in the Arctic threaten not only its ecosystems but also have economic and cultural implications. The traditional way of life of local communities, closely tied to Arctic wildlife, is particularly at risk. The research underscores the necessity of proactive measures to mitigate the diverse effects of climate change on the Arctic region.
“Researcher Henrik Christiansen from the Greenland Institute of Natural Resources, who is one of the driving forces behind the study, emphasizes the importance of the results: ‘This study is the result of a long-term and extensive collaboration that has provided us with a large dataset to examine how polar cod populations across the Arctic are connected. It is particularly interesting that the polar cod in West Greenland shows signs of local adaptation. This should be taken into consideration when developing plans for the conservation and management of the population.'”
Contact information:
Scientist Henrik Christiansen, Greenland Institute of Natural Resources phone: +299 361200 or mail: hech@natur.gl
