Impact of B.C. drought on province’s fish could be severe, experts say

The province’s drought has become a problem almost every year in British Columbia, but while drought concerns mostly surround how it will affect the wildfire situation, it’s also affecting fish survival.

“Drought basically occurs with high water temperatures as well and it basically has two major effects, it reduces the quantity of water and the quality of water which means the water is less suitable for the fish to survive in,” said Eric Taylor, a UBC professor in the Department of Zoology.

Retired UBC professor in the Department of Earth, Ocean and Atmospheric Sciences, Michael Healey, adds that in some cases the drought can be fatal for fish.

“Just like us — when the temperatures get too high, their body functions start to shut down and they die. Similarly, if temperatures get too low then they also start to lose body function and die,” Healey said.

With the drought causing water levels to drop, Taylor says this could prevent fish from moving to different lakes or streams, creating higher concentrations of fish in smaller areas.

“If the fish get concentrated and the water temperature is high, there’s more fish trying to get a smaller amount of oxygen,” Taylor said.

“So the higher the water temperature, the less oxygen is in the water and particularly for fish like salmon or trout they need that cool water because they just prefer that cool water, but also they have a relatively high oxygen demand.”

If these severe droughts and extremely high temperatures persist year after year, there could be bigger problems, especially in the Okanagan.

“I would think if temperatures rise much more, the Okanagan is quite likely to become uninhabitable by salmon,” Healey said.

The Okanagan was just recently moved to a level 4 drought and while that’s not welcome news for the region, the drought may not be the biggest problem for fish, Healey says. It’s the extreme heat that likely will be.

Taylor says people have to start being mindful of their water usage during restrictions, to help mitigate the drought.

“The thing is to follow the advice and take responsibility and be informed about drought levels in your particular area and to act on the advice of municipal and provincial authorities. To say, ‘I didn’t know about water restrictions,’ you can’t act that way anymore,” said Taylor.