A salmon swimming up a river of British Columbia. (Photo: Stock File)
Fraser River floodgates could affect salmon survival
Thursday, October 05, 2017, 22:50 (GMT + 9)
Two new studies show that floodgates on the Fraser River could be reducing habitat for salmon — and there is little oversight when it comes to checking the ecological impact of that infrastructure.
“Past research in our lab had found that these floodgates were associated with low oxygen quantity in the creeks flowing into the Fraser through the floodgates,” said Rebecca Seifert, the lead author of a study by Simon Fraser University (SFU), Metro News reported.
“They were seeing a dead zone where it was hard for sensitive fish like trout and salmon to survive,” the scientist pointed out.
Researchers explained that the floodgates reduce the flow of water, meaning more algae grows around the gates and lowering the oxygen level and found more invasive species and fewer native species near floodgates.
When the gates are closed, juvenile salmon can’t get out of the creeks where they were born to pass down the Fraser River and out to the open ocean, an important part of the salmon life cycle.
Seifert wanted to know just how often the floodgates were closed, so she installed timelapse cameras. She found that many of the gates, which close when high water pressure pushes them closed, are shut almost all the time during the high-water spring season. That’s also when juvenile season are trying to migrate to the Fraser.
A separate study by the University of Victoria and Watershed Watch found that there is a regulatory gap when it comes to tracking the impact infrastructure like floodgates are having on fish.
“We want municipalities, who often own and maintain flood infrastructure, to build it to be fish-friendly,” said Lina Azeez, a campaigner with Watershed Watch. “The technology exists.”