The St. Joseph and Kalamazoo rivers showed no signs of invasive silver and bighead carp, environmental DNA samples collected May 1 show.
According to Michigan Department of Natural Resources fisheries biologist Nick Popoff, none of the 260 eDNA samples indicated the presence of genetic material for the carp. The samples were analyzed by the U.S. Fish and Wildlife Service.
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The eDNA surveillance program is a collaborative effort between the Great Lakes states and the U.S. Fish and Wildlife Service that samples high-priority locations for the presence of bighead and silver carp genetic material.
Samples were taken from 200 sites on the Kalamazoo River and 60 sites on the St. Joseph River. The Grand, St. Joseph and Kalamazoo rivers have two more monitoring events scheduled this summer, with lab results expected in July and August, according to the DNR.
Concerns regarding invasive carp reaching Michigan waters increased when an 8-pound, 27-inch-long silver carp was captured June 22 in the Illinois Waterway during an Asian Carp Regional Coordinating Committee monitoring event.
According to the DNR, the fish was caught nine miles from Lake Michigan, about 27 miles beyond the electric barrier system meant to keep the fish from entering the Great Lakes.
“Invasive carp thrive and reproduce in large, warm-water rivers with ample flow,” said Nick Popoff, a DNR fisheries biologist. “Michigan’s southwestern Great Lakes tributaries provide suitable habitat and sufficient food, in the form of algae, to support these species.”
The state of Michigan only has jurisdiction and management authority over Michigan’s waters, and the Illinois Waterway and the Chicago Area Waterway System locks are operated by the Army Corps of Engineers.
According to the DNR, Michigan waters could sustain major ecological changes that could cause losses to the $7 billion commercial and sport fishing industry. Also, the potential of injury to boaters and swimmers caused by leaping silver carp could negatively affect the state’s $38 billion tourism economy.
“Along with our participation in the eDNA surveillance program, we continue to be diligent with early detection efforts, such as conducting fish population surveys, increasing awareness among anglers, and maintaining an invasive carp reporting website for anglers to share any suspicious catches or observations that occur during their outings,” said Tammy Newcomb, the DNR’s senior water policy advisor.
According to the DNR, if invasive carp are detected in Michigan waters, the state has a plan that includes intensive monitoring, netting and electrofishing to remove invasive fish. If necessary, an aquatic pesticide, rotenone, would be applied.
“Controlling and eradicating aquatic invasive species is an extremely costly, difficult and long-term undertaking, with no guarantee of success. Preventing invasive carp from entering the Great Lakes is a far better prospect,” Newcomb.
Anglers are asked to report potential invasive carp sightings at michigan.gov/invasivecarp.
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