Without more data, some salmon in B.C. and Yukon could face 'undocumented extinction,' study says

CBC

26-01-2025

A lack of crucial data in vast Northwestern watersheds risks "undocumented extinction" of some salmon, according to a new study.
Produced by the Pacific Salmon Foundation, a B.C.-based non-profit organization, the research looks at a region that encompasses B.C., Alaska and Yukon. The river basins in the area are roughly 110,000 square kilometres — more than three times the size of Vancouver Island.
And yet, there's a huge blindspot on the keystone species there, the study says.
"We actually know very little about most salmon in the northern transboundary region, and this is because monitoring has tended to focus on economically important stocks," said Stephanie Peacock, the lead author.
That monitoring data on chinook and sockeye salmon is limited to major basins, including the Alsek and Taku Rivers.
Pink, chum and steelhead — basically, a type of rainbow trout that migrates — are also in the region which is so ecologically intact the study calls it a "salmon stronghold."
But it also states there's little to no monitoring of those species, or in smaller basins of, among others, the Chilkat River, near Haines, Alaska. For some salmon, like those that spawn in the Blanchard River, located near the B.C.-Yukon border along the Haines Road, there are no surveys whatsoever. That means the status of fish there is unknown.
Peacock said this problem is because of how fish are managed under the Pacific Salmon Treaty, which by and large focuses on counting the number of fish swimming into major rivers. That treaty was signed by Canada and the U.S. in 1985 as way to cooperatively manage and conserve Pacific salmon stocks.
Together, the countries gauge the strength of a given run to help determine sustainable harvest levels. At least that's the intent of the agreement.
However, Peacock said as designed, the system overlooks things.
"Monitoring in this region doesn't capture biodiversity," she said. "Salmon are not homogenous."
Within every run are genetically diverse groups. Some salmon are just wired differently. Take sockeye, some of which prefer to spawn in rivers, while others do so in lakes, the study states.
Peacock said this needs to be accounted for in the region, along with the age and size of fish.
Without that key information, she said how to conserve the fish will remain a big question mark.
"If we're not monitoring to try and understand how those diverse groups are doing, we run the risk that they might be declining or even becoming extinct — without us even knowing," Peacock said.
What's the research suggest?
Across the board, the study suggests salmon in the region are facing a decline in abundance from decades ago. For instance, like their Yukon River cousins, chinook numbers in the region have experienced steep drop-offs since around 2000, the study states.
But when researchers dug a little deeper into available data and assessed salmon biodiversity they found some silver linings. One potential bright point: the strength of a distinct group of coho.
Monitoring along the Klukshu River, a tributary of the Alsek, whose headwaters are in the Yukon, shows that the number of coho increased by about 600 per cent compared to the historical average. That's about 12,000 fish.
However, Peacock cautions that because the full extent of the run hasn't been monitored, this could be an anomaly. Coho also spawn late, when ice possibly covers rivers. The study states this makes surveys challenging.
Then there are sockeye, which also appear to be trending in the right direction, Peacock said. During the same year and in the same river, there were about 13,700 of them. That's a roughly 16-per-cent increase compared to the historical average.
In October, the Alaska Department of Fish and Game de-listed Klukshu sockeye as a "stock of concern."
There's big tension in the region. Many rivers are glacially fed, making water temperatures potentially more hospitable in the face of climate change, the study states. But there are also risks to habitats: wildfire and mining.
The study states large fires in 2018 in northern B.C. affected 100 per cent of summer spawning habitat for steelhead in the Stikine.
The study states there are 120 mines — active or otherwise — across the region. Of those, 28 are located within known spawning habitat.
"It is probable that there is much more salmon habitat across the region, which we were not able to identify due to limited publicly available data on spawning locations," the study states.
"The transboundary region is rich in mineral resources and there is a high likelihood that mining development will increase substantially in the years to come, particularly as glaciers recede and new habitats become accessible to mining exploration."
Elizabeth MacDonald, with the Yukon Salmon Sub-Committee, a non-governmental advsiory body, said the research is important because it highlights northern needs.
"These fish are so very, very important to people and I think oftentimes, because they do get forgotten about, it does a great disservice not just to the environment but the people who depend upon them," she said.
What needs to happen?
The Pacific Salmon Foundation says several things need to happen, including filling in existing data gaps with information on salmon biodiversity, conducting more research on habitats and their quality, and making data readily accessible and easy to comprehend.
Examples of all these include attaching radio tags to salmon to understand their long voyages and patterns in between, as well as developing more comprehensive mining threat assessments, which evaluate the risks such as tailings dam failures.
Peacock also suggests giving First Nations more resources to develop and carry out monitoring and management efforts of their own.
"This means funding, training opportunities, infrastructure, but also supporting less conventional projects that bring people together, engage youth and foster that connection," Peacock said. "That will be critical to ensuring salmon have a future. People need to care about salmon."
The Pacific Salmon Treaty is about to be renegotiated, as it is every 10 years. Peacock said now is the time to advocate for broader provisions, to account for biodiversity among salmon. A new agreement will be implemented in 2028.
"Both in salmon, but also in their habitats. This might involve things like moving away from reliance on hatchery production and greater incentives for habitat protection and restoration, with the goal of promoting self-sustaining diverse, wild salmon populations," Peacock said.