First silver carp, the 'flying' invasive fish, is captured in St. Croix

A silver carp, the invasive fish with the notorious reputation for flying out of the water to the peril of boaters, has been captured for the first time in the St. Croix River bordering Minnesota and Wisconsin, conservation officials said Thursday.

The Minnesota Department of Natural Resources said it confirmed the capture, made Friday by a commercial angler near Prescott, Wis., who was working in conjunction with a DNR fisheries biologist.

"This news is disappointing but not unexpected," said DNR invasive fish coordinator Nick Frohnauer.

Frohnauer said this carp, measuring 33 inches long and weighing 13 pounds, was captured within sight of where the St. Croix and Mississippi Rivers meet. In 2014, two silver carp were captured in the Mississippi a short distance upstream from the confluence.

In 2011, state and federal conservation officials announced that DNA tests had suggested presence of the silver carp in the St Croix as well as the Mississippi.

The same commercial angler also caught a bighead carp, also invasive but not known to bound out of the water. Bighead have previously been caught at this same location and farther up the St. Croix.

Frohnauer noted that while the DNR is concerned about the potential impact of invasive carp in the St. Croix, these specific captures do not indicate reproduction or an established population of either bighead or silver carp in the river.

"The location where the carp were captured is a well-known overwintering area for several species of fish," Frohnauer said. "At this time, it is hard to predict if these individuals would have moved further upstream in the St. Croix River, or back into the Mississippi River when water temperatures warm up in the spring."

Once the ice clears, DNR staff will work with commercial anglers to watch for additional invasive carp near Prescott.

Videos have been online for years showing silver carp flying out of the water and landing in boats and striking their occupants. One video alone has been viewed nearly 6 million times showing two boaters ambushed by silver carp along the Wabasha River in Indiana.

Minnesota boaters "shouldn't fret too much" that the same flying frenzy is imminent on this state's rivers and lakes, said John Waters, a DNR fisheries specialist.

"We haven't seen any jumping silver carp" in Minnesota, and the chances of that phenomenon happening in the state are "real low right now," Waters said. "Usually, we see them jump in areas where there are a lot of them." Discoveries so far in Minnesota have been just one or two at a time.

To prevent the spread of various unwanted carp, the DNR's invasive species program has partnered with state and federal agencies, conservation groups, university researchers and commercial businesses.

The Minnesota Aquatic Invasive Species Research Center at the University of Minnesota is testing various deterrents to carp in Mississippi River locks and dams. These strategies include manipulating the lock and dam's spillway gates to create consistent, high-velocity stream flows too powerful for the carp to overcome, and installing a noise-blasting system that is paired with lights and a deflecting shield of air bubbles.

While no breeding populations have been detected in Minnesota waters, individual invasive carp have been caught in the Mississippi near the Twin Cities, the St. Croix River and the Minnesota River.

Various breeds of invasive carp, native to China, were brought here to cleanse algae from fish farms and sewage treatment ponds in the South. They have been progressing upstream since escaping into the Mississippi River amid flooding in the 1970s.

These large fish compete with native species and are a potential threat to recreational boating in every Great Lakes state and Ontario. Electric barriers are set up in the hope of keeping them out of Lake Michigan.

Since 2010, more than $388 million has been spent to battle the invasive species — mostly by the federal government.

The Associated Press contributed to this report.
Paul Walsh • 612-673-4482