Warming oceans welcome salmon to the Arctic

Recent research has revealed a fascinating development in the Arctic: Pacific salmon, traditionally scarce in these icy waters, are venturing into the Canadian Arctic in greater numbers.

This shift, linked to warmer ocean temperatures, suggests that climate change is paving new pathways for these fish.

Pacific salmon in the Arctic

Salmon have not typically thronged the Arctic Ocean and its tributaries. However, in recent years, local fishermen have reported occasional increases in salmon catches.

This uptick in sightings and captures has been particularly notable among subsistence fishermen, hinting at significant ecological changes.

These changes suggest that Pacific salmon are not only adapting to – but also thriving in -environments previously considered too harsh for their survival, potentially altering the local marine ecosystem.

How salmon navigate new waters

Researchers at Fisheries and Oceans Canada and the University of Alaska Fairbanks, in collaboration with local communities in the western Canadian Arctic, have discovered that the surge in salmon numbers correlates with a series of warm, ice-free periods in the Arctic Ocean north of Alaska.

The study highlights a two-part mechanism facilitating this migration. Initially, warm late-spring conditions in the Chukchi Sea, northwest of Alaska, lure the salmon northward.

If these conditions extend into the summer in the Beaufort Sea, northeast of Alaska, the salmon journey continues into Canadian waters.

This correlation was confirmed by comparing data from the National Oceanic and Atmospheric Administration (NOAA) with local salmon catch rates since the year 2000, underscoring a clear link between salmon abundance and favorable ocean conditions.

“You need both gates to be open, which is fascinating in itself. If they don’t align in terms of having open, ice-free water, salmon don’t turn that corner,” noted Professor Curry Cunningham.

Broader implications

The Arctic Salmon Program, a collaborative effort with Indigenous communities, has tracked these unexpected salmon appearances for over two decades.

Subsistence harvesters, targeting species native to Arctic waters, have documented salmon catches outside their typical range, providing valuable insights into the changing Arctic ecosystem.

Karen Dunmall, a research scientist, noted the broader implications of these findings. “It really helps to address some questions from community members about biodiversity change and subsistence and how they feed their families,” she said.

Local observations

The research not only informs local communities but also contributes to a greater understanding of how species adapt to rapidly changing climates.

Frankie Dillon, an Indigenous fisherman, shared his surprise upon encountering his first salmon in 2010 in the northern Yukon. “I had to ask, ‘What kind of fish was that?’” Dillon recalled.

Before this encounter, the only salmon he had seen were on television, highlighting the rarity of such sightings in the region.

Northward Pacific salmon migration

With climate models predicting that the conditions enabling this northward migration of salmon through the Chukchi and Beaufort seas will become more common by the 2040s, the study’s findings are not just a local phenomenon but a sign of broader ecological shifts affecting the entire region.

These changes are not confined to Canada; salmon are also appearing off the coast of Alaska, indicating a region-wide impact.

Joe Langan, a postdoctoral fellow who co-led the research, emphasized this broader perspective: “It’s not as if these fish are all skipping Alaska and heading to Canada. Some of these salmon are ending up on Alaska’s North Slope too.”

As the Arctic waters continue to warm, the migration of salmon into these new territories not only reshapes local fishing practices but also provides a clear, swim-by-swim report of how global climate change is altering our world.

Pacific salmon 

Pacific salmon are a group of fish known for their anadromous life cycle, meaning they are born in fresh water, migrate to the ocean for their adult life, and then return to fresh water to reproduce and die. 

This fascinating life journey is marked by remarkable transformations in their body physiology and coloration to adapt to different environments. 

Main species

The five main species of Pacific salmon – Chinook, Coho, Sockeye, Pink, and Chum – are primarily found in the rivers and coastal waters of the northern Pacific Ocean, particularly around North America and northeastern Asia.

Ecological role 

These fish play critical roles in their ecosystems. They serve as prey for a variety of wildlife, including bears, eagles, and orcas, and their decaying bodies provide important nutrients to aquatic systems and forest ecosystems when they die after spawning. 

Cultural and economic significance 

Pacific salmon are also culturally significant to many indigenous groups in the Pacific Northwest, who rely on them for food, trade, and as a central element of their spiritual and cultural practices.

Commercially, Pacific salmon are a valuable resource for fisheries, with their rich, oily meat being highly prized for its flavor and nutritional content. 

Threats 

However, they face several threats, such as habitat loss, pollution, climate change, and overfishing, which have led to significant declines in some populations, prompting efforts to manage and conserve these iconic fish.

The study is published in the journal Global Change Biology.

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