MINNEAPOLIS - Scientists have found evidence that invasive Asian carp have spawned much farther north in the upper Mississippi River than previously recorded.
The U.S. Geological Survey says Asian carp eggs, including late-stage embryos nearly ready to hatch, were recently identified in samples collected as far north as Lynxville in southwestern Wisconsin. That's 250 miles upstream from previously known reproducing populations. And it says the spawning would have occurred upstream from the site.
The service's Midwest regional director, Leon Carl, says the presence of eggs in the samples shows that spawning occurred, but it's not known if any eggs hatched and survived in that area.
Scientists are still trying to confirm whether the eggs are from bighead or silver carp, though it's possible some of the eggs are from grass carp.