Chum salmon runs were hit hard this year, by first drought and then flooding, with their numbers decimated in the face of extreme weather.

ThatB次元官网网址檚 according to Peter McCully, a technical advisor for the volunteer-run Goldstream Hatchery who also works with the Department of Fisheries and Oceans. The hatchery had projected 20,000 chum would enter the river this year. They saw about 4,000.

B次元官网网址淭he drop was precipitous and weB次元官网网址檙e all sort of scratching our heads B次元官网网址� why is that?B次元官网网址� he said. B次元官网网址淏ecause other species like coho and chinook did appreciably well.B次元官网网址�

There are a number of factors, McCully said. Higher water temperatures, not just in the rivers but offshore in the Pacific Ocean, have changed a lot of things, from the quality of food chum are getting to the number of predators in the same waters. Coho and chinook salmon, which stay closer to shore than chum, are less impacted. Not only are less chum returning to spawn, theyB次元官网网址檙e also smaller.

READ MORE: VIDEO: Goldstream salmon swim beside picnic tables amid surging stormwaters

While salmon species in the area have somewhat adapted to the seasonal shifts in water levels and temperatures, changes between summer and fall are becoming more extreme, said Bethany Coulthard, a University of Nevada hydro-climatologist who lives and works in Shawnigan Lake.

B次元官网网址淲e are getting to the point where species probably arenB次元官网网址檛 able to cope,B次元官网网址� she said. B次元官网网址淭hey canB次元官网网址檛 be resilient to the level of extremes that theyB次元官网网址檙e facing under climate change now.B次元官网网址�

While there are a number of long-term impacts, one of the most pressing may be the damage the flooding caused to river habitat, McCully said.

The impacts of NovemberB次元官网网址檚 heavy rains were spread throughout the province and affected a number of salmon spawning beds. But the Goldstream River may have it worse, he said.

The additional water flows washed away large amounts of gravel, which salmon depend on to form nests and lay their eggs. McCully said itB次元官网网址檚 a particular problem because the Goldstream River is fed by a reservoir, which doesnB次元官网网址檛 gradually supply the river downstream with more gravel.

The gravel could be replaced, but it would take a lot to rebuild the riverbed habitats, he said.

B次元官网网址淪o much of it is left up to mother nature too, but I donB次元官网网址檛 think the different government agencies really have a handle on the scope of the damage. ItB次元官网网址檚 going to take years to rectify it.B次元官网网址�

bailey.moreton@goldstreamgazette.com
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