Cardigan River's waters are clear after last year's fish kill, and residents are cautiously optimistic
DFO unable to determine what caused over 300 fish to turn up dead in the eastern P.E.I. river
The cause of a fish kill last summer in an eastern P.E.I. river remains a mystery, and some are keeping a close eye on the state of the water.
Fish began showing up dead in the Cardigan River, near the 48 Road, in June 2024. The total number of more than 300 dead included brook trout, rainbow trout, juvenile salmon and stickleback.
Nearly a year later, the waters are clear, which has people who use the river pleased.
"It's really encouraging, because I'm actually putting my fishing line in… I can follow it all the way down, I can see it all the way down," said Ivan Hughes, who grew up fishing in the Cardigan River.
"I think if it's good for me, it's also going to be good for the fish."
Fish kills can happen for several reasons: algal blooms, droughts, infectious diseases, or heavy rain washing silt into a shallow water system, possibly accompanied by traces of agricultural or industrial chemicals.
At the time the dead fish were discovered, officials also noticed a thick, smelly sludge in the water.
But testing of samples done by Fisheries and Oceans Canada, or DFO, the month after the fish kill showed no abnormalities in the water and were inconclusive as to the cause.
This month, DFO said that remains the case.
"On July 9, 2024, Fisheries and Oceans Canada (DFO) received the results from Environment and Climate Change Canada, which showed no abnormalities in the water chemistry of the collected samples," the agency said in a statement to CBC News.
"As such, the tests are inconclusive and DFO has closed the investigation in this matter."
The report does suggest water quality could have been an issue at the time. It said things like water temperature or nutrient levels could have been issues.
While the tests showed higher levels of chloride, sodium and nitrogen near a fish hatchery settling pond, the amounts were within environmental guidelines.
Gideon Pringle, the managing director of the Mowi hatchery, said in an email, "There is no reason to believe that our facilities were in any way connected with the fish kill that was reported."
We want people to come back into... the streams around Cardigan and fish again and enjoy them just like we did 30, 40 years ago.— Ivan Hughes, Cardigan River Community Group
There is cautious optimism from people like Hughes about what could happen with the river this year.
He put together a group of around 20 concerned residents, the Cardigan River Community Group, who have been working with Mowi and the provincial and federal governments to keep the waters clean.
"You're almost devastated thinking that we had nice healthy waters here and how would this happen, why would it happen? Just quite concerned for the stream itself because this was an enjoyable place to be and for fish to be killed in it, we weren't very happy," he said.
"The name of the game here is we want people to come back into this stream and the streams around Cardigan and enjoy them and fish again and enjoy them just like we did 30, 40 years ago."
About 4,000 brook trout fingerlings were released into the river after the kill, and Hughes said he hasn't seen any dead fish in the area since the fish kill last June.
With files from Tony Davis