A few videos on youtube showing fish kills in USA in 2009
Big Fish Kill on Big Eau Pleine
By Paul A. Smith of the Journal Sentinel
Apr. 2, 2009
As the ice recedes from Wisconsin waters, the annual assessment of winter fish kills begins. One of the biggest of the season is being reported on Big Eau Pleine Reservoir near Wausau.
According to Tom Meronek, DNR fisheries biologist in Wausau, as many as 70 to 80 percent of the fish in the lower section of Big Eau Pleine may have died.
While some fish kills are natural, the Big Eau Pleine event is being linked to water management practices and runoff from agricultural sources. The water level this winter reached 17 feet below full pool, according to Mike Paul, vice president of the Big Eau Pleine Citizens Organization (BEPCO).
"That's about as low as it's ever been," said Paul. "Some fish got stranded in pools and died. Others got hit by the low oxygen level and couldn't survive."
Rafts of dead fish are washing up on shorelines in the 6,830-acre impoundment on the Big Eau Plaine River. The reservoir connects to Lake DuBay and the Wisconsin River system. The dead fish include walleye, northern pike, crappie, musky and rough fish.
The water's dissolved oxygen level dropped to 0.1 to 0.2 parts per million, said Meronek, so low that even carp and bullhead couldn't survive.
Although an aerator was used to help increase oxygen levels, it couldn't prevent the fish kill. Meronek said levels of oxygen were higher in some of the riverine arms of the reservoir; it won't be known until later this month how many fish survived by swimming into such areas.
The large fish kill is particularly disheartening to anglers; the Big Eau Pleine had become a prized destination for walleye in recent years. Walleye, northern pike and crappie reproduced naturally and showed good growth rates in the reservoir. Only musky were stocked, according to the DNR.
According to a 2003 DNR fisheries assessment, the reservoir had about 7 adult walleye per acre. And in spring 2006, after yet another kill, the DNR found 250 walleye per hour in a shoreline electroshocking survey.
"The numbers of walleye were outstanding," said Meronek. "We'll do another assessment this month to help understand how bad the fish kill was."
The lake, which receives substantial agricultural runoff, has been hit with numerous fish kills in the last decade.
The water levels in Big Eau Pleine are controlled by the Wisconsin Valley Improvement Corporation; it uses water in the reservoir to provide power for the area, including paper mills. WVIC has a permit from the Federal Energy Regulatory Commission that allows it to lower water levels to 17 feet below full pool.
So it was acting within its permit this winter. But BEPCO, the local citizens' group, intends to petition FERC to alter the permit.
"We've got to get the water level maintained at a higher minimum level," said Paul. "This can't happen again."
Perhaps one of the bright spots in a grim story is this - after successive fish kills, local citizens decided they needed to organize and become active in issues related to the flowage. BEPCO was formed just three months ago, said Paul.
The fishery is likely to take several years to recover. Meronek said results of the DNR's walleye assessment should be known at the end of April.
In southeastern Wisconsin, some dead fish have been reported on Big Muskego Lake, on Vern Wolf Lake in Kenosha County and on the boating channels around Okauchee Lake. But the numbers are pretty typical, said Sue Beyler, area fisheries supervisor for the DNR, and not cause for special concern.
Anglers or others who spot unusual numbers of dead fish are encouraged to contact their local DNR office.