TRAVERSE CITY, Mich. (AP) — Genetic material from Asian carp has been found in the Kalamazoo River in southwestern Michigan, but there's no indication the invasive fish have become established in the river that flows into Lake Michigan, officials said Tuesday.
DNA from silver carp was detected in one of 200 water samples taken in July from the river in Allegan County, this one from below the Caulkins Dam about 24 miles from Lake Michigan, the state Department of Natural Resources and the U.S. Fish and Wildlife Service said.
The discovery marks the first time so-called environmental DNA for silver carp has been found in Michigan's Great Lakes waters outside of Maumee Bay in Lake Erie. The term "environmental DNA" refers to genetic markers that fish leave behind as they move through waters, shedding scales, mucous or excrement.
Scientists have been testing waters for Asian carp DNA in an effort to track their progress toward the Great Lakes. Bighead and silver carp were imported to the Deep South from Asia in the early 1970s and escaped into the Mississippi River, where they have been migrating northward since. They have invaded numerous tributaries including the Illinois River, which leads to Lake Michigan, although authorities have installed electric barriers near Chicago in hopes of stopping their advance. The large, voracious fish compete with native species for food.
The discovery of genetic markers doesn't necessarily prove the presence of live carp, as scientists say it could come from other sources, such as fishing gear or bird droppings that came in contact with the DNA. But some contend the presence of live fish is the likeliest explanation.
"While we don't have evidence of a live fish in the water, we treat this finding very seriously," Michigan DNR senior water policy adviser Tammy Newcombe said.
The agency has requested assistance from the Fish and Wildlife Service for additional surveillance on the lower Kalamazoo River, and authorities planned to begin collecting an additional 200 samples Tuesday. Results should be available within a month.
Also, the DNR will boost presence of its staff along the river, which is popular for recreational activities such as fishing and boating, to ask anglers to report any Asian carp sightings. The agency plans to place information in local bait shops to heighten public awareness.
Asian carp details: http://1.usa.gov/1vNpl0c
Identification video: http://bit.ly/1vNoUmC
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