The spring thaw has at Kyrktjärn, a lake in the northern Swedish county of Jokkmokk, has uncovered huge quantities of dead fish. As the thick ice began to melt after the winter freeze, the dead fish - mostly pike - rose to the surface. Locals suspect that the cause was the snow machines used on nearby ski slopes, which have pumped water from the lake leading to a lack of oxygen....
Apparently, during a winter fishing competition at the lake, no fish were caught at all. New water should have been pumped back into the lake during snow making. This didn't happen though, because of fears that it would lead to dangerously thin ice.
http://www.thelocal.se/article.php?ID=3755&date=20060509