The invasive Asian carp might have made its first appearance in Minneapolis, about 25 miles from the Wisconsin border. The Minnesota DNR said yesterday that samples near the Ford Dam on the Mississippi River have tested positive for the carp’s DNA. That’s about four months after similar DNA indicated a presence of the silver carp on the Saint Croix River at the Wisconsin border.
Minnesota’s DNR says it will hire a commercial fisherman begin netting-and-searching operations below the Ford Dam, to see if any actual Asian carp can be found.
It is too early to know what effect, if any, the animal, a copepod -- a crustacean known as Neoergasilus japonicus -- will have on the lake. Researchers have seen little damage in Saginaw Bay, a part of Lake Huron, where the copepods were found in 1994.
"It seems to be a relatively innocuous parasite," said Rochelle Sturtevant, the regional extension coordinator for Michigan Sea Grant. "But they do have the potential to disperse quickly."
The copepods, which are native to eastern Asia, first appeared in Europe in the 1960s. Within 20 years, they had crossed the continent.
From there, they moved to Finland and Cuba.
In 1994, they were found in an aquaculture pond at Auburn University, in Alabama. Every fish there was infected.
The copepods have since been spotted in Colorado, in Saginaw Bay and, on Sept. 26, in the western basin of Lake Erie.
A biologist there found two samples on the dorsal fin of a green sunfish.
The animals are tiny. Adults are just a half-millimeter long.
They make up for it with numbers: Each female can produce 2,000 eggs, which mature within 21 days.
Copepods use hooks at the ends of their antennae to latch onto a fish's dorsal fin. U.S. researchers have found as many as 44 on a single fish.
Sunday, October 23, 2011 at 1:43PM 
