LYNXVILLE, Wis. — Asian carp eggs, including late-stage embryos nearly ready to hatch, were recently identified in samples collected in May and June from the Mississippi River at Lynxville, Wis., which is about 20 miles downriver of the Minnesota border.
"The presence of eggs in the samples indicates that spawning occurred, but we do not know if eggs hatched and survived or whether future spawning events would result in live fish," said Leon Carl, Midwest regional director of the U.S. Geological Survey that took and analyzed the samples. "This discovery means that Asian carp spawned much farther north in the Mississippi than previously recorded."
The eggs are about 250 miles further upriver than any previously known reproducing population, he said. Spawning would have happened upriver of the site and the eggs drifted down.
The eggs and late-stage embryos were identified as either bighead carp or silver carp. It is also possible that some eggs could be from grass carp, although no eggs were visually identified as such. The USGS attempted genetic analyses to definitively determine which species of Asian carp the eggs belong to, but the results were inconclusive.
"Invasive Asian carp could pose substantial environmental risks and economic impacts to the Upper Mississippi River if they become established," Carl said.
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For more information on Asian carp research, the Asian Carp Regional Coordinating Committee (ACRCC) website at http://asiancarp.us.
