Coming soon? A new invasive species found in McPherson

John Green
The Kansan
Researchers recently discovered a previously undocumented, invasive species of crawfish in Kansas' McPherson State Fishing Lake. Both male and female Rusty Crayfish were found in the waters by researchers.

It has not been found in Harvey County lakes just yet, but a new invasive and aggressive type of crayfish has been found in McPherson County. 

State wildlife officials say visitors there and to other small water bodies around the state should also be on the lookout after an initial Kansas Department of Wildlife and Parks-funded university research project focused on the freshwater crustacean found multiple Rusty Crayfish in the McPherson State Fishing Lake.

It is likely a matter of time before they make their way to Harvey County if precautions are not taken. Those measures include draining boats and livewells before leaving a lake, and not transporting wild-caught bait from one lake to another. 

According to Kyle McCaskey, director of public information for Harvey County, those guidelines are already in place for Harvey County parks. Those guidelines were issued after a zebra mussels began to spread in Kansas.  

It is not known, yet, when testing of the waters of Harvey County might occur — researchers are still working on how to test waters. 

"We have not generated [a testing] list yet," said KDWP Aquatic Nuisance Species coordinator Chris Steffen. "This is just the research phase of the project to determine protocols for future sampling. The goals of this 2-year university project are to determine the type and number of trap sets needed to detect all species of crayfish in a lake." 

Anglers, boaters, and watersport enthusiasts are encouraged to keep their eyes open for this invasive species, which can be identified by its trademark large, black-tipped claws and rust-colored spots on its upper shell.

If one is discovered, freeze it in a sealed plastic bag, note the date and location of capture, and contact KDWP’s Emporia Research and Survey Office at (620) 342-0658.

The large, aggressive crawdad is not only known to attack the feet of unsuspecting humans and animals standing in freshwater, according to a KDWP news release, but it outcompetes both native fish and crayfish species for forage. That forage also acts as an important cover for select prey species.

"It is impossible to know exactly what and exactly how severe the ecological impacts will be to a lake when an invasive species is introduced, especially in a case like this where the species is new to the state," Steffan told The Kansan. "In other areas of the country, Rusty Crayfish have reduced the amount and types of aquatic plants, invertebrate populations, and some fish populations. There is no feasible way to remove the Rusty Crayfish. Negative impacts to a lake may be permanent. "

The captured samples included both males and females of varying ages, indicating a reproducing population is established there, officials said.

Rusty Crayfish have not previously been documented in the wild in Kansas, making this official “discovery” the first of its kind. 

KDWP’s Aquatic Nuisance Species Program and Ecological Services section funded the project with the overarching goal of establishing sampling protocols that could then be used for long-term monitoring of both native and invasive crayfish in Kansas, the release stated.

To the surprise of staff and researchers, the find in McPherson validated the need for the protocols as quickly as the research project began. McPherson is just one of several small waterbodies slated to be inspected in the state.

“The most likely cause of the Rusty Crayfish making its way into Kansas is through its use as fishing bait,” stated KDWP Aquatic Nuisance Species coordinator Chris Steffen.

“This species is a prime example of the importance of always draining water from your boat, live well and bilge before leaving a water body," Steffen said. "And of never moving bait from one waterbody to another. You just never know what could be hitchhiking a ride.”

Staff and researchers working on the crayfish project will continue to experiment with multiple capture methods and techniques on a small number of water bodies around the state.

Once researchers identify an effective and efficient sampling protocol, staff will continue the sampling efforts across a large number of lakes across the state.

For information on other aquatic nuisance species in Kansas, visit

— Chad Frey, Newton Kansan, contributed to this report