Scores of dead fish have surfaced along the banks of a small river that connects Crooked Lake and Round Lake on Cowessess First Nation.

Edward Aisaican, a resident of Cowessess, first noticed the fish Sunday evening.

"I noticed there was lines and lines of dead fish along there [the riverbank]. And I pulled over and I stopped, and I took a few pictures, and I dropped my cousin off,” Aisaican said. “This isn’t common, not this bad. I’ve never seen it this bad.”

Aisaican contacted the Saskatchewan Water Security Agency shortly afterwards. The Agency began their investigation into what caused the fish kill on Monday.

After some initial tests, cyanobacteria, also known as blue-green algae has been found on the fish and in the water. The Agency doesn’t believe the deaths are directly related to any type of sewage dumping as was rumoured, but instead believe it’s extremely likely the toxic algae is to blame.

"We looked into it but there was nothing to substantiate to say that [sewage] was the cause,” said Patrick Boyle, Executive Director of Communications and Client Services with the Water Security Agency. “I know that’s an immediate concern but ultimately if there is that, the sewage dumping into a body of water, what it does is add nutrients in [the water], and that helps the formation of blue-green algae.”

Cyanobacteria usually forms at the beginning of the summer months, but recent warm fall weather and the mostly dry summer could be to blame for the formation of the algae.

“For this time of year it’s not all that surprising given, outside of the rain we’re getting currently, we have had a really dry year so far.”

The Agency says they expect the algae will clear up within two to three weeks, although the process could be sped up by colder weather conditions. Until then nearby residents are instructed not to eat any of the fish from the river and to not allow pets or livestock to drink from the water, causing concerns for residents like Aisaican on the First Nation.

"All of our people go out this time of year and start to hunt, and they feed their families with this meat and I’m really concerned that somebody might get ill.”