Biologists track invasive species reaching ‘impressive sizes’ in Neosho River

TOPEKA ( KSNT ) – Kansas wildlife officials are switching up their tactics to manage a large invasive fish species creeping into one of the state’s rivers.

Biologists with the Kansas Department of Wildlife and Parks ( KDWP ) are turning their efforts to the Neosho River in southeastern Kansas this year in a combined effort with the Oklahoma Department of Wildlife Conservation ( ODWC ) and Missouri State University (MSU) to understand the movements of invasive carp species. These fish are part of a larger family of invasive fish currently plaguing the state’s rivers, lakes and reservoirs.

Liam Odell, an invasive carp biologist with the KDWP, told 27 News in a written statement that biologists are turning their attention from invasive carp in the Kansas River to study and tag bighead and grass carp found in the Neosho River which runs from Morris County down into Oklahoma’s Grand Lake system. These fish can currently be found in the river from the dam in Oswego to the Oklahoma-Kansas state line, according to the KDWP’s Aquatic Nuisance Species waters map .

“With invasive fishes, there is always risk for expansion via flooding, hence why we have began tracking seasonal movement to gather information,” Odell said. “The furthest up they could make it in the Neosho River is to John Redmond Dam, they can not make it into the lake.”

Biologists use gathered data to monitor the seasonal movements of the invasive carp to get a better understanding of their spawning behaviors. This also helps biologists find new ways to target and remove the carp from the state’s waters.

“Bighead carp currently exist in low densities and reach impressive sizes in the Neosho/Grand Lake system,” Odell said. “We do not have any baseline data to determine the effect bighead carp are having on native fishes in the system. However, as per USGS , bighead carp are large planktivorous fish that have the potential to deplete zooplankton populations and outcompete native planktivorous fish like bigmouth buffalo and paddlefish.”

Invasive bighead carp can get up to five feet in length and regularly reach 40 pounds, according to U.S. Fish and Wildlife ( FWS ). Some members of the species have been found weighing more than 100 pounds.

The KDWP, ODWC and MSU began tagging bighead and grass carp in the spring and summer of 2024. In Kansas, there are three bighead and four grass carp which have been successfully tagged for the telemetry project and re-released, marking a shift in tactics from removing them outright upon collection from the water.

“With the new telemetry project getting started we have not been actively removing bighead carp,” Odell said. “However, with the help of Grand Lake anglers and Oklahoma Paddlefish fishing guides ODWC removed around 80 bighead carp from the system before we began tracking them.”

Generally, anglers are encouraged to remove any invasive species they find and destroy them in accordance with standards set by the American Fisheries Society. This includes spinal cord dislocation or decapitation methods for carp. It is illegal to either return a carp to the water alive or possess them in Kansas.

KDWP biologists have removed thousands of pounds of invasive carp since efforts initially began in 2022. Odell told 27 News earlier this year that 61,000 pounds of carp have been removed from the Kansas River running from the WaterOne Dam in Kansas City to the Bowersock Dam in Lawrence.

Invasive carp represent some, but not all, of the invasive aquatic species causing problems in Kansas. Other species, like zebra mussels , white perch and silver carp, are also impacting numerous reservoirs and rivers across the state.

Anglers are encouraged to use best practices to prevent them from spreading further into the state. More information on aquatic nuisance species laws and regulations can be found by clicking here .

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