Teams scour side-channels to rescue fry stranded by low flows on Cowichan River
As water flows on the Cowichan River continue to drop, a rescue mission is underway to “salvage” salmon and trout fry stranded in isolated pools and side channels.
Water flows from Cowichan Lake into the Cowichan River will be reduced to 4.5 cubic metres per second effective Friday — then will hold at that level.
The fry are being salvaged by Environmental Dynamics Inc., consultants contracted by the Paper Excellence pulp-and-paper mill in Crofton. “We’re saving lives, that’s why we’re here,” said biologist Leo Chira.
The Crofton mill operates a weir, or dam, that regulates water flows from Cowichan Lake into the Cowichan River.
The goal is to maintain enough water in the lake to sustain fish and fish habitat in the river during the dry season — and also to meet the Crofton mill’s operating needs.
“We’re a big water user,” said Brian Houle, the mill’s environment manager. The mill currently uses water at a rate of 1.3 cubic metres per second, which is down from 1.6 at full operating capacity.
The mill maintains a water-intake facility about four-fifths of the way down the river.
This isn’t the first time that dry conditions have generated concerns in the river.
Pumps were installed in 2016 for the first time due to low water levels, but the pumps weren’t actually used until 2019, for three weeks, to move water from lake to river.
Fisheries and Oceans Canada, the BC government and Cowichan Tribes have all approved the plan to reduce flows to 4.5 cubic metres per second, Houle said.
On Wednesday morning, sixmountains.ca accompanied Chira and his colleague, Sharlene James, as they rescued fry alongside the Cowichan River below Skutz Falls.
One day earlier, the two biologists rescued about 850 fry, most of them coho, returning them to the main river. Two other biologists are at work elsewhere on the river.
Chira explained that the decision to salvage fry is site-specific, depending on factors such as the amount and quality of the water and the number of fish.
At one side channel no longer connected to the main river Chira obtained a temperature reading of 13.4 degrees Celsius — that’s about five degrees cooler than the river due to the influence of ground water and shade.
Adult fish become stressed when river levels reach about 20 degrees; fry are even more vulnerable.
The decision is to leave these fish where they are. “They’re doing fine,” Chira says. “This is a very large pool. And the density is low.”
Nearby, the biologists wade into a much smaller pool, working a couple of pole seines in tandem to scoop the fry up. “It’s exciting when you pull it up and there’s lots of fish,” James says.
Meanwhile, Aaron Frisby, owner of The Tube Shack in Lake Cowichan, said they’ve encountered flows of 4.5 cubic metres per second previously and will continue to operate throughout the summer. “There are no spots where people have to get out and walk or anything like that.”
Tubers who floated 2.5 hours in the past can expect to be on the river another 15-20 minutes due to the low flows, he said.
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— Larry Pynn, June 28, 2023