Pacific Salmon Move North to Arctic Canada When Conditions Are Right

pacific-salmon-move-north

Pacific salmon are extending their range northward into Arctic Canada. This shift is largely due to warming ocean temperatures, which create favorable conditions for the fish to travel further than before.

The phenomenon is a significant indicator of how climate change is affecting marine ecosystems.

Researchers have noted that these movements are linked to a series of warm, ice-free periods in the Arctic Ocean near Alaska.

The collaboration between scientists and local communities in western Canadian Arctic regions has been crucial in documenting and understanding these ecological changes.

Favorable Warm Conditions in the Northern Seas Enhance Pacific Salmon Migration Northwards

Two chum salmon show the distinctive stripes that emerge after they enter freshwater to spawn.

Movement of Pacific salmon into Arctic waters is becoming increasingly common as the northern seas warm.

Research has shown that when the Bering Sea, Chukchi Sea, and Beaufort Sea experience warm conditions simultaneously, the migration path for salmon extends all the way to the Western Canadian Arctic.

Residents in Arctic Canadian communities have observed fluctuations in salmon availability, prompting scientists from Canada and Alaska to investigate.

A study revealed that for salmon to traverse the Bering Strait, cross the Chukchi Sea, and enter the Canadian Beaufort Sea, warm conditions are essential throughout these vast ocean areas.

Joe Langan from the University of Alaska Fairbanks, a lead author of the study published in Global Change Biology, explained the necessity of a warm Chukchi Sea during late spring.

This is typically accompanied by a warm Northern Bering Sea. Beyond the Chukchi, a warm coastal Beaufort Sea is also crucial for the migration corridor to remain open.

Historically, these seas did not always follow the same temperature patterns, with some remaining cold while others warmed.

The melting of sea ice earlier in the season results in rising water temperatures and delayed ice formation, leading to more simultaneous warming. This convergence allows the ocean gateway for salmon migration to remain open more consistently.

Pacific salmon appearances in the Canadian Arctic waters remain unpredictable.

In 2019, a year marked by uniformly warm ocean waters, abundant Pacific salmon were seen, and harvests were high. Conversely, in 2022, colder waters led to no salmon being caught in these Arctic Canadian communities.

Karen Dunmall from Fisheries and Oceans Canada, another lead author, pointed out that successful passage through the Bering Strait, Chukchi Sea, and Beaufort Sea is only part of the process for salmon populations to establish themselves that far north.

In 2017, a significant discovery was made when a juvenile chum salmon was found in Jago Lagoon, near Canada-Alaska border on the Arctic coastline—a sign of successful reproduction in new Arctic territories.

Since then, more discoveries have been made.

In the previous year, a team from the University of Alaska Fairbanks found roughly 100 chum salmon spawning in tributaries of the Colville River, a major river on Alaska’s North Slope flowing into the Beaufort Sea.

Though spawning does not guarantee successful reproduction, it marks another significant step in the northward spread of Pacific salmon.

Arctic Canadian community residents, who have traditionally harvested Arctic species, have expressed concerns about the implications of salmon presence.

Questions arise about potential disruptions. They ask if the salmon will dominate the rivers, affect other species like the char, or compete for food resources.

Even in places like the Mackenzie River, where salmon harvesting is part of the tradition, the appearance of different salmon species can be unsettling. Concerns extend beyond the practical to what these changes signify about a transforming climate and Arctic.

Researchers continue to investigate the impact on native species like Dolly Varden, which also spawns in freshwater before migrating to the saltwater.

While the Arctic’s warming trends make it possible for salmon reproduction that far north, the cold winter remains a challenge. Salmon must meet specific conditions during their reproductive cycle to succeed.

Ongoing research is focused on the food sources available to salmon in the Arctic and whether the new arrivals might introduce disease pathogens.

Meanwhile, other species like pollock and Pacific cod are also moving northward, through the Bering Strait and into the East Siberian Sea, as indicated in a Russian study published in the Progress in Oceanography.

These species are leaving behind warmer waters that now have less ice due to climate change.

As Arctic communities and ecosystems adapt, scientists emphasize the importance of monitoring these movement patterns to understand the broader implications of climate change on marine life.

Posted by Thomas Callaghan

I hold a degree in Marine Biology and have spent years conducting fieldwork, from the coral reefs of the Pacific to the deep trenches of the Atlantic. My work focuses on understanding the intricate relationships within marine ecosystems and the impact of human activity on these fragile environments.