A new report suggests that the Asian carp threat to Great Lakes fisheries could be greater than previously believed.
U.S. and Canadian researchers say that just 10 mature females and even fewer males could establish a population in all five lakes --- if they gain entry. Previously, some said that hundreds of carp probably would be needed for a successful invasion.
Michael Hansen, chairman of the Great Lakes Fishery Commission, calls the report sobering.
"It concludes that arrival of Asian carp is looming, and should the fish become established in the Great Lakes, that their effects on the ecosystem would be severe."
"Ever since these non-native fish first escaped and began to breed prolifically in the rivers of the Midwest, the questions everyone has been asking are: 'Can a breeding population survive in the Great Lakes and would it be a significant problem if they did?'" said Marcia McNutt, director of the U.S. Geological Survey.
"Now we know the answers and unfortunately they are 'yes and yes.'"
How might the carp gain entry into the Great Lakes? Most likely they will migrate into Lake Michigan through a series of canals that connect the Great Lakes to the Illinois River and the massive Mississippi River watershed. Already carp DNA has been found above an electric barrier intended to repel the invaders, just a few miles from Lake Michigan.
But now, sadly, carp DNA also has been found in Lake Erie.
“The results from these water samples are certainly concerning, as this marks the first time Asian carp eDNA has been detected in water samples from Lake Erie, or any of the Michigan waters intensively surveyed for the presence of invasive carp,” said Michigan DNR Fisheries Division Chief Jim Dexter.
Meanwhile, the U.S. Army Corps of Engineers still is pondering a strategy to keep the carp out of the Great Lakes.