From a recent article by the CBC:
An unusually cool spring is being blamed for a high number of fish dying along Lake of the Prairies in recent weeks.
The man-made reservoir from the Shellmouth Dam was drained by the provincial government this year to control flooding, and now it's at the lowest level it's ever been. Videos have surfaced on YouTube in recent days, including one showing many dead walleye in shallow waters along the lake.
Some fishermen are blaming the province for the fish kill, but officials say the fish are getting trapped under the ice because of the lack of spring runoff and the fact that there is still a lot of ice.
"An active runoff would have filled these depressional areas and re-oxygenated the water in which the fish are … being impacted due to low oxygen levels," Steve Topping, who works in the province's water management division, told CBC News.
"[In] 2011 we had the same situation, but we didn't get a fish kill. And the reason was it was much earlier runoff," he added.
Topping said when officials lowered the reservoir levels, they had thought the spring runoff would have arrived by now.
The impact of the fish kill on fishing is expected to be minor, Topping said.
Visit http://www.cbc.ca/news/canada/manitoba/story/2013/04/18/mb-dead-fish-lake-of-the-prairies-manitoba.html for more details.
