© Rory O’ConnorThousands of dead fish have surfaced in three Central Alberta ponds and lakes because of winterkill.
Thousands of dead fish have surfaced in three Central Alberta ponds and lakes because of winterkill.
In Crimson Lake, thousands of perch died and collected around the shoreline.
While not pleasant for lake visitors to look at or smell, winterkill is a natural phenomenon.
"They're very common in Alberta," said Jessica Reilly, senior fisheries biologist out of Alberta Environment and Parks Rocky Mountain House office.
In Central Alberta, winterkill was also reported at Dickson Trout Pond and Pine Lake."Basically what happens is the plants and algae in the lake over winter die and decompose. When they decompose they use up oxygen."
The longer the decomposition, the more oxygen is used up. That is exacerbated in a long winter because oxygen can't be replenished while the water is covered by ice.
Comment: There seems to have been a high number of such incidents involving this species over the last 2 years, see also: Body of whale shark found washed ashore in Tamil Nadu, India; third in the region since May
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Whale shark found washed ashore in Tamil Nadu, India
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Dead whale shark found in Tamil Nadu, India
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Whale shark found dead at Palghar, India
Dead whale shark discovered on coast of Bukas Grande Island, Philippines