Biologists are trying to get to the bottom of a mystery at Buffalo Pound. Thousands of fish have been found floating on the surface of the lake.

The Saskatchewan Wildlife Federation has been investigating and Fisheries Biologist Adam Matichuk did some initial testing last week, thinking low oxygen levels in the lake caused the fish to die. But that wasn't the case and now they're looking at other possible causes. "Perhaps a toxin, herbicide or pesticide or something completely different because it could be a disease as well."

Some specimens have been sent to Saskatoon for further testing. Matichuk doesn't think there is a risk to anyone using the lake, including those who eat fish caught in the lake.