By Dan Egan of the Journal Sentinel
July 13, 2012
The battle against Asian carp has taken on a new front.
Evidence of the voracious, jumbo carp that have been advancing up the Chicago Sanitary and Ship Canal toward Lake Michigan shows the fish – or at least their DNA – have recently been detected in the Great Lakes, in Lake Erie.
Six water samples taken in August show the presence of silver and bighead carp in the shallowest – but most fish-friendly – of the five Great Lakes, said Chris Jerde of the University of Notre Dame.
Jerde said the nearly yearlong lag between the sampling and Friday’s announcement was because that sampling wasn’t part of a concerted hunt for Asian carp. Instead, it was used to test the lake for a range of potential invasive species. That created a lab backlog.
Politicians pounced at the news, saying it’s time to bump up the effort to stop the spread of a fish that some say could destroy the Great Lakes $7 billion recreational and commercial fishery.
“This alarming discovery underscores the need for action now to stop Asian carp and other invasive species from devastating our Great Lakes and the hundreds of thousands of Michigan jobs that depend on them,” U.S. Sen. Debbie Stabenow of Michigan said in a news release. “Temporary fixes have proven inadequate, and evidence of this dangerous invasive species is now being detected for the first time in the Great Lakes.”
Several bighead carp had been netted in Lake Erie since the mid-1990s, but biologists have never detected a breeding population. Scientists who studied the carcasses to trace their growth rate have speculated the carp had somehow arrived in the lake from fish farms.
Four of the positive samples announced Friday were from bighead carp; two were from silver carp.
DNA sampling on the Chicago Sanitary and Ship Canal since 2009 have shown evidence of both species, though to date only one bighead carp had been caught above an electric barrier on the canal designed to stop the fish. That fish was caught in the summer of 2010 about 6 miles south of Lake Michigan.
The Lake Erie positive samples didn’t surprise Jerde because of the previous finds. He said the samples can’t reveal anything about fish numbers or whether there is a reproducing population, but he does believe they indicated at least some fish are swimming in Lake Erie.
“There is every reason to believe there might be a few live bigheads swimming around Lake Erie,” he said.
The federal government has maintained positive DNA samples in the Chicago waters near Lake Michigan do not equate to the presence of live fish.
Federal scientists have contended that the genetic material could be arriving above the barrier by some other means, such as barge bilge water, bird excrement or sewer outfalls.
Asian carp are on the menu of many Asian restaurants.