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Climate change may be contributing to fish kills and algae blooms, P.E.I. scientists say

More than 200 fish were found dead in the Morell River last weekend, and blue-green algae warnings have been issued for two ponds in eastern P.E.I. (Brian Higgins/CBC - image credit)
More than 200 fish were found dead in the Morell River last weekend, and blue-green algae warnings have been issued for two ponds in eastern P.E.I. (Brian Higgins/CBC - image credit)

Climate change may be starting to have an impact on aquatic life on Prince Edward Island, scientists say.

One week ago, crews removing a culvert blockage spotted the first signs of a fish kill in Morell, and two instances of blue-green algae blooms sparked provincial warnings in eastern P.E.I. this week.

Data scientist Gregor McEwen said when water temperatures change, the level of aquatic life in a location will change, too.

"Animals have heat tolerances… There's a certain temperature range, so if it gets too hot, things will just die. "

The reasons behind fish kills are complex and multifaceted. But the hot sun warming shallow water doesn't help.

The fish kill in Morell, which happened in a shallow branch of the river, left more than 200 fish dead.

The hotter river water gets, the less oxygen it has — and preliminary tests of the water showed there wasn't enough oxygen for some fish to survive.

Rosie MacFarlane, a provincial fisheries biologist, said sections of the Morell River can reach the mid-20s in summer.

Kate McKenna/CBC
Kate McKenna/CBC

"We did have a heat wave this year, and things got very warm."

Added McEwen: "A temperature rise here will cause lots of issues for local life because they're used to different temperatures."

Blue-green algae produces toxins that are harmful for people and animals. Blooms are fairly uncommon on P.E.I., with only 14 being reported in the last 20 years. But there are two being monitored at the moment, one at Black Pond in the Souris area and the second at MacLures Pond in Murray River.

Heat is a factor in how long such blooms will last, McEwen said.

As one adaptation measure, he suggests planting trees along waterways to keep water temperatures down.

"It shows the possibility that such things may increase unless we do things to mitigate the effect."