Is road salt killing Pacific salmon? That's what a new B.C. study is trying to find out

Salmon spawning in B.C.'s Stoney Creek. (Image credit: UBC)

As wintry weather hits Metro Vancouver, a team of researchers is looking at whether an increase in the use of road salt could be harming and even killing local salmon.

Dr. Chris Wood, a professor in the department of zoology at the University of British Columbia, is one of the lead researchers on a five-year project that will engage academics and citizen scientists in an attempt to measure salt levels in local rivers and streams and the impact on both the salmon and their food sources.

"We know that Pacific salmon are in precipitous decline and the situation with the runs in the Vancouver Lower Mainland is especially critical. It's a multi-factorial, multi-stress situation we believe. But one important component -- which we believe has been overlooked -- is the potential impact of road salt runoff," Wood tells CTV News.

"We know that this salt is dangerous to aquatic life."

First, with the help of locals, "streamkeepers" data will be gathered measuring the salt levels in 30 to 50 local streams set to be studied.will be measured. Then, lab-based researchers will expose freshly-fertilized salmon eggs to the same levels of salt and observe the impact.

"We're trying to see whether the salt levels we're recording in the streams in the Lower Mainland are impacting the growth of the fish, the survival of the fish, the behavior of the fish, the physiology of the fish and in the end -- their ability to go to sea," Wood explains.

At the same time, researchers will be conducting similar studies on some of the invertebrates that salmon eat – like worms, midges and mayflies.

"We may find, in fact, that the impact on the food source is actually greater than the impact on the health of the fish themselves," Wood says.

One of the reasons behind the study is a significant uptick in the use of road salt. In Canada, the amount used is increasing at about 2.5 per cent per year. In B.C. the amount has increased five-fold in the last decade, Wood says, from 200,000 metric tonnes to one million. This data, he notes, is based on voluntary reporting and may not be 100 per cent accurate.

"But certainly the apparent trend is upward both nationally and provincially," he says.

Wood says the project will see collaboration between scientists from three universities, a network of volunteers and citizen scientists, and the Canada's Department of Fisheries and Oceans. In addition, it will have an outreach component, meant to encourage people to reconsider how much salt they use, opt for pet-friendly products that are thought to be less harmful to salmon, and to use sand as an alternative if possible.

“If we can educate the public and create some interest in the political sphere, that's going to help the salmon in the long run," Wood says.