British Columbia sockeye salmon spawning was affected by a waterfall. (Photo: Stock File)
Cement blocks come to the rescue of ailing salmon
Wednesday, August 17, 2011, 22:50 (GMT + 9)
Large cement blocks have been flown in and placed within the Kwinageese River to help returning salmon reach their spawning beds. Airlifted by helicopter, nearly 40 blocks meant to raise a 3m-pool below a waterfall were placed in this tributary of the Nass River in British Columbia (BC).
Thus far, salmon have been unable to get past the waterfall and raising the pool will give the fish a better chance of clearing it, said Harry Nyce, Nisga’a Lisims Government fish and wildlife director.
“It was a combination of putting our heads together – our people, federal fisheries and our biologists,” he commented.
Meetings between provincial, federal and Nisga’a officials bred a plan in late July and into early August with final permits finally issued last week. The whole project may cost CAD 50,000 (USD 50,686) and is shared by several agencies, Terrace Standard reports.
In the long term, officials want to blast the slide, but not until the winter season when water levels are low, Nyce explained.
Meanwhile, officials will be observing the salmon closely to determine if the block scheme worked.
It started in 2009 when biologists and others with the Nisga’a Fisheries and Wildlife Department first began to perceive a sharp decline in spawning Kwinageese River salmon.
Although Kwinageese numbers were up at test fishery locations, people noticed that very few actually reached the spawning grounds, according to biologist Richard Alexander.
The Department of Fisheries and Oceans (DFO) closed a part of the Nass commercial sockeye run this year and the Nisga’a also restricted fisheries to allow as many Kwinageese salmon as possible to get upriver.
But more people began to suspect that the salmon might be up against a physical obstruction, and they finally noticed that a 3m-wall was disabling the salmon from getting past. It was caused when large chunks of rock fell off a canyon wall and into the water, creating a waterfall some 3m-tall.
“What we say is that anything above 2 m is impassable. That’s 6.5 ft,” said Alexander. “At 3 m, you're getting on to 10 ft.”
Fisheries officials believe the blockage has been up for at least several years, which explains why spawning numbers have been low as of 2009.
Alexander explained that officials are trying to determine the exact date through satellite imagery dating back several years, so they can better gauge the types of closures and restrictions that should be enforced to ensure as many Kwinageese salmon as possible make it up the Nass to their spawning grounds in the coming years.
Returns for 2014 and 2015 are thus far expected to be paltry.
By Natalia Real