Since mid-July, an estimated one million chum salmon have migrated into the Yukon River from the Bering Sea, according to Fisheries and Oceans Canada. Yet, researchers caution that this surge does not necessarily indicate a positive trend for the species’ population.
Experts observed a troubling decline in chum salmon numbers in 2020, raising concerns about the lack of understanding behind both the decline and the recent increase. Sebastian Jones, a wildlife analyst at the Yukon Conservation Society, expressed worry over the ecosystem’s unpredictability, emphasizing the limited control or knowledge of such phenomena.
Canadian-origin salmon constitute around 12% of the returning fish, a decrease from the typical range of 20-30%. Despite this, Jones noted an improvement compared to recent years, with hopes for 100,000 chum salmon crossing into Canada this year, although still below the desired range of 150,000 to 250,000.
Stephanie Peacock, a scientist at the Pacific Salmon Foundation, highlighted chum salmon as one of the two salmon species returning to the Canadian side of the Yukon River, alongside chinook salmon. Peacock underlined the significance of chum salmon’s late migration, providing essential nutrients in the fall.
Both chum and chinook salmon populations have witnessed declines, with a gradual decrease in chinook since the 1990s and a more rapid decline in chum salmon in recent years, raising greater concern. Researchers are investigating changes in the Bering Sea, the starting point for these salmon’s upstream journey, where shifts like rising water temperatures and increased industrial trawl fishing have occurred, impacting the ecosystem in incompletely understood ways.
Peacock urged cautious optimism, emphasizing the continued decline in Yukon chum salmon numbers over the long term, despite the recent influx. She stressed the need to address the ongoing concerns to ensure the species’ sustained well-being.