More chum salmon entering Yukon River, but experts say that’s not a clear sign of recovery

Since the fall chum salmon season began in mid-July, Fisheries and Oceans Canada said it estimates about a million salmon have entered the Yukon River from the Bering Sea.

However, researchers say this increase is not necessarily a sign the population of this particular species is on an upward trend.

In 2020, researchers recorded an alarming drop in chum salmon numbers.

“It’s very worrying, and not least because we don’t really know why the numbers have gone down, just like we don’t know why the numbers came back up this year,” said Sebastian Jones, a wildlife analyst at the Yukon Conservation Society.

“It shows just how little control or understanding we have of some of these ecosystems.”

Researchers say the number of Canadian-origin salmon makes up about 12 per cent of the returning fish, when it usually falls between 20 and 30 per cent.

While the number is still low, “it’s definitely considerably better than we’ve seen in the last few years,” said Jones.

Last year, he added, about 25,000 chum salmon crossed the border into Canada. This year, the hope is for 100,000 fish to cross.

“It’s still not quite up where it should be, when we’d like to see … 150,000 and 250,000 chum salmon coming into the Yukon,” said Jones.

Cautiously optimistic

Stephanie Peacock is a scientist with the Pacific Salmon Foundation. She said chum salmon are one of two salmon species that return to the Canadian side of the Yukon River. The other being chinook salmon.

“[Chum salmon] tend to migrate later than chinook,” Peacock continued, saying they provide a “really important” source of nutrients later in the fall.

Both species have seen a drop over time.

“For chinook, we saw a pretty gradual steady decline since the 1990s,” Peacock said. “I think the decline in chum salmon is almost more concerning because it’s happened over a much shorter time scale.”

Jones said researchers were investigating the Bering Sea, where the Yukon River feeds into the ocean, and where these salmon begin their journey upstream.

“It’s kind of an enclosed ocean, an enclosed ecosystem,” Jones said, adding that it’s seen a number of changes in recent years, such as an increase in average water temperature and more industrial trawl fishing.

Jones said those two factors have impacts on the ecosystem “we don’t fully understand.”

Looking at the current numbers, Peacock says “it’s good to be optimistic” but cautioned can’t be thrown to the wind.

“We have to take a step back and look at how much things have declined over the longer term and realize there’s still a pretty big concern for Yukon chum salmon.”