For first time, DNR tags carp in bid to learn more about invasive fish
The Minnesota DNR has captured a bighead carp and, for the first time in the state, tagged it to learn more about invasive carp.
After a period of acoustic telemetry tracking to learn more about its range and other behaviors, the tagged invasive carp will be removed from the water and euthanized. The data will increase the DNR’s ability to capture invasive carp when they enter Minnesota waters.
“This new tool is another proactive step Minnesota is taking to prevent the spread of invasive species,” DNR invasive fish coordinator Nick Frohnauer said. “The more we can learn about these species, the more effectively we can continue to minimize their potential impact, with the help of Minnesotans who use rivers for business or recreation.”
On Friday, July 28, the DNR captured a 37-pound, 43-inch bighead carp in the St. Croix River, surgically implanted a thin, 4-inch long tracking tag and returned the fish to the river. Daily tracking by boat has shown the fish’s precise range, feeding areas and other details about the types of conditions these species prefer.
The DNR won’t know some things about this fish, such as whether it’s an egg-bearing female, until after they recapture, euthanize and examine it.
The Minnesota Legislature granted the agency the authority to use tagging as a research tool. Legislative approval was needed because the agency is putting an invasive species back into the water for a period of weeks.
“It’s important and legally required, as always, that anyone who catches a bighead, grass or silver carp in Minnesota contact the DNR immediately,” Frohnauer said. “Invasive carp are rare in Minnesota, with typically just a few individual fish reported in the state each year. We can keep it that way with the public’s help, more research and continued vigilance.”
The DNR is permitted to track up to two invasive carp in the St. Croix or Mississippi River at any given time. Anyone who catches a bighead, grass or silver carp must report it to the DNR immediately. Call 651-587-2781 or email firstname.lastname@example.org. Take a photo and transport the carp to the nearest fisheries office or make arrangements for it to be picked up by a DNR official.
The DNR has been preparing for the opportunity to tag and track invasive carp. Last summer, DNR fisheries biologists John Waters and Joel Stiras successfully tested the technique on a bigmouth buffalo, a native river fish similar in habits to invasive carp. They netted the fish in Pool 2 of the Mississippi near Inver Grove Heights and implanted it with an acoustic transmitter. After releasing the fish, they tracked it for several days and re-captured it in a backwater area near Cottage Grove.
Invasive carp have been progressing upstream since the 1970s, when they escaped into the Mississippi River from southern fish farms, where they were used to control algae. These large fish compete with native species and pose a threat to rivers and lakes. While no breeding populations have been detected in Minnesota waters, individual bighead and silver carp have been caught in the Mississippi, St. Croix and Minnesota rivers.
More information about invasive carp is available at www.mndnr.gov/invasivecarp.