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[RalphH]

Chinook salmon barely stand a chance against climate instability on the Nooksack River

Globe and Mail
Nathan Vanderklippe
Dec 15, 2021

Inside the trays stacked 16-deep at the Skookum Creek Fish Hatchery, 740,000 eggs are being incubated into spring Chinook salmon. They are almost certainly the only fish of their kind this year in the south fork of the Nooksack River, the Washington state waterway that has been home to one of the more successful fish restoration programs in the United States.

Months of severe weather have dealt the program a major setback. First, summer heat killed thousands of fish in the river. Then November’s flooding scoured the gravel beds where survivors had deposited their eggs. The confluence of disasters has, in vivid fashion, brought to the fore the toll of rising temperatures on the natural world and demonstrated how climate instability can create a deadly succession of dangers.

“That’s two historical events the salmon have gone through in one season,” said Dana Wilson, a fisherman and member of the Lummi Nation, which today is situated at the outlet of the Nooksack.

There have been moments this year where he has found himself thinking: “Is this the end of the world?”

“This is all part of the connections of the natural ways of things,” he said. “What devastation is coming next year – or even this spring?”

For the Lummi, who have worked to bring back these fish, the double hit to the spring Chinook is likely to diminish the possibility of continuing a harvest of the fish, only recently restarted, in years to come. It’s also raising new questions about the river’s ability to support a natural population of the salmon, a concern for Canadian waterways, too, since the Nooksack flows just 20 kilometres from the Fraser River, which is experiencing similar climatic conditions.

Nooksack Chinook are “very vulnerable right now, and there’s a lot of evidence that things aren’t looking good for them into the future,” said Tom Chance, the salmon enhancement program manager for the Lummi, who oversee the Skookum Creek hatchery.

The Lummi have longed valued Chinook for their size and early runs, which traditionally marked an end to the lean season. The fish are also a preferred source of food for a small population of resident orcas in Puget Sound and the Salish Sea, which are classified as an endangered species. The effort to nurse the Lower Nooksack spring Chinook back to health has been considered important enough to merit its own funding from Congress. In 2015, just 11 fish came back to the Nooksack’s south fork. Since then, the number has reached hundreds, and the hatchery has in recent years incubated about 1.9 million eggs.

This year, however, it was only able to gather less than half that. “We lost 2,500 fish out in the river before they could even make it back to the hatchery,” said Mr. Chance. Record summer heat hastened the spread of bacterial infections, leaving the Nooksack littered with bleached white salmon bodies.

Then came the mid-November floods, which sent torrents coursing down the river (some of its flood waters poured into the Abbotsford area of British Columbia, submerging farms and drowning animals). Chinook salmon dig their redds – a depression where they deposit eggs – as much as 30 centimetres into the river bottom. In one part of the Nooksack measured by the U.S. Geological Survey, the river gouged almost two metres out of its bottom.

“Anything that had laid eggs, its progeny is gone,” said Kevin Clark, the regional hatchery manager for the Washington Department of Fish and Wildlife. For many salmon, the risks of increasingly severe weather mean that “without hatcheries, the habitat is just not there to support it any more,” he said. Already, researchers have estimated that native salmon runs in the area have declined to less than 8 per cent of their size in the late 1800s.

In the Fraser River system, researchers believe this year’s floods caused “significant” damage to salmon populations, but it will take years to know exactly how serious it was, said Marvin Rosenau, a fisheries biologist at the B.C. Institute of Technology. But the floods didn’t just destroy redds, he noted, as another concern is the “stranding of juvenile and adult fish that wandered out into the floodplain during the high discharges and then couldn’t find their way back to the main stream.”

Salmon and other fish have the capacity to navigate torrential rivers, and Mr. Clark has been impressed by the ability of later-season species, such as chum salmon and steelhead trout, to push through flood waters.

At the state-run Kendall Creek hatchery, however, the bodies of dead chum salmon lay floating in brood ponds on a recent morning. The hatchery is located on a Nooksack tributary, and unusually high numbers of fish have returned this year covered in fungus. “They’re not in good shape,” Mr. Chase said. He believes sediment driven at high velocity by flood waters abraded their flesh, stripping away the mucus that normally protects them from pathogens.

“How do we prevent this in the future? We have very few options,” he said. To help the salmon, “you have to get rid of the levees.” Restoring the rivers to their natural floodways would help restore salmon habitat.

People living in those floodways have called for the opposite, saying it’s time to raise levees to prevent further flooding.

For some in the Lummi Nation, however, this year’s deadly toll on salmon makes the case for a new approach. “We should acknowledge floodplains and we should yield to them,” said Troy Olsen, a Lummi fisherman.

Mr. Wilson also pointed to the headwaters of the Nooksack, part of which flows from glaciers in the North Cascades mountains that have lost roughly 30 per cent of their volume since 1984. The shrinking glaciers have created further concern for salmon, since they are a source of water flows in the warmer months, with scientists warning that lower water levels could damage salmon’s ability to spawn.

The fate of the Nooksack’s salmon, Mr. Wilson said, underscores the immensity of the climate-related problems now accumulating, and the importance of addressing fundamental causes.

“Are we at a time that we need to really look at climate change and quit thinking it doesn’t exist?” he said.

“There isn’t a quick fix on this.”

https://www.theglobeandmail.com/world/article-chinook-salmon-barely-stand-a-chance-against-climate-instability-on/

[CohoJake]

There are a couple of slight inaccuracies in this story, but it is good overall. Neither tribal fishers nor anglers have been allowed to fish for South Fork chinook since the population has been rebuilt - only North Fork fish, which is a distinct population with better returns overall. The South Fork unfortunately is naturally a much warmer stream and it will be a miracle if any of these fish can survive a few more degrees of climate warming.

I think the hatchery fish could have fared better if they were released much farther upstream as smolts, so they would have gotten to the cooler headwaters before the summer temperatures climbed too high. The hatchery isn't very far up the South Fork. I know there is a steady population of Summer Steelhead that spawn in the South Fork, and I didn't hear about any mortality for those fish, I think because they were all upstream past the dangerous temperatures before it was too late.

[RalphH]

Thanks for filling in some detail. I think hatcheries will have to look at changing how they operate. Releasing smolts upstream so returning adults head to the same location and avoid  spending the summer in warmer water sounds like a good approach but no doubt will impose financial costs.

I also though the article is indicative of how  climate change and extreme events such as this summer's heat dome and the November floods impact salmon stocks in our local rivers, streams, lakes and wet lands.