ERIE, PA — Trace amounts of genetic material from an invasive fish species known for leaping errantly from the water has been detected in Lake Erie.
On July 21, the Pennsylvania Fish and Boat Commission (PFBC) disclosed that environmental DNA, or eDNA, from silver carp — an invasive fish formerly known as one of four different types of Asian carp — was found in routine sampling around Presque Isle Bay in Erie, Pennsylvania.
The sample was collected in May by the U.S. Fish & Wildlife Service (FWS), which notified the state on July 11. The genetic material was found at only one of 100 sample sites around the bay. No live fish were found and the DNA presence doesn’t automatically mean a fish is present.
Nonetheless, the detection triggered an electrofishing search around the bay which did not turn up any silver carp, said Mike Parker, spokesperson for the PFBC.
“The protocol moving forward is just to continue testing,” he said. The FWS is expected to conduct follow-up testing when lake temperatures cool in the fall and conditions are more favorable.
“It’s a red flag but a small one compared to what would occur if repeated or multiple samples came up positive,” Parker said.
The detection is a first for Presque Isle Bay, but not the first time invasive bighead or silver carp eDNA detection has sparked a search in Great Lakes waters far from where the fish are known to be established in parts of Illinois, Ohio, Indiana, Kentucky and West Virginia.
Genetic material testing is used by researchers and officials as an early warning too. In Michigan, a positive eDNA sample from the Kalamazoo River sparked a 2014 search that did not find any fish or more positive samples. A similar, fruitless search was performed in parts of the Ohio River in Pennsylvania that year after invasive carp DNA samples were found.
Invasive silver and bighead carp are established in the Ohio River and various tributaries downstream of the Robert C. Byrd Locks & Dam at Gallipolis, Ohio.
The U.S. Army Corp of Engineers studied the potential for invasive carp to cross from the Ohio River watershed to the Lake Erie watershed in 2010 and found no viable pathways.
Should they become established in the Great Lakes, bighead and silver carp would have a major disruptive impact on sport fishing and recreational boating. Silver carp could injure people by leaping from the water when disturbed and both species would likely compete with native fish for food and habitat.
Most attention has been paid to the invasive carp in Illinois, where an $850 million effort is beginning to fortify the Brandon Road Lock & Dam, a chokepoint dam on the Des Plaines River near Joliet positioned as a last line of defense to keep the fish from Lake Michigan.
“Any detection of eDNA is concerning but we have seen this happen before without evidence of a fish or a history of detection,” said Molly Flanagan, chief operating officer for the Alliance for the Great Lakes nonprofit in Chicago, an advocate for the Brandon Road measures.
“You need a critical mass of fish to establish a population,” Flanagan said. “One detection of eDNA doesn’t give you a critical mass and there are lots of ways eDNA could get into the water.”
In a news release, the PFBC posited several potential scenarios for the detection, including “bird feces, water transported in the live well of a recreational boat recently in waters infested with silver carp, or from melted ice used to store silver carp at fish markets that flowed into storm sewers.”
Flanagan said the detection underscores the need to keep momentum behind the Brandon Road project, which is undergoing pre-construction engineering and design work.
Flanagan said Illinois needs to sign an agreement with the U.S. Army Corps by the end of 2022 to keep it on schedule. The Alliance is expecting the project to get an assist from Congress, where lawmakers are working to increase the federal government’s share of the project cost to 90 percent with a 10 percent match from affected states.