Hot dogs and minnow traps: an effective approach to controlling invasive rusty crayfish

A pack of hot dogs and a minnow trap may seem like unlikely tools for conservation, but new research from the Natural Resources Research Institute at the University of Minnesota Duluth shows they can be surprisingly effective at tackling invasive rusty crayfish in local lakes.

Although rusty crayfish are native to states within the Ohio River Basin, such as Illinois, Ohio, Tennessee, and West Virginia, they are not native to Cook County or the Great Lakes region. According to the Minnesota Department of Natural Resources, the invasive crustacean was likely introduced to northern Minnesota through improper disposal of live bait or aquarium releases.

Compared to native crayfish species, rusty crayfish have caused ecological harm in lakes by destroying aquatic vegetation and displacing native crayfish species.

“We know that rusty crayfish are becoming a problem in northern Minnesota lakes for vegetation, particularly sensitive vegetation,” said Valerie Brady, lead researcher for the rusty crayfish project with NRRI.

Brady said, “They do a lot of clipping with their claws, which is hard on wild rice.”

NRRI Tech Shelby Suhr with a full trap | Photo by NRRI

In 2023, a team of NRRI researchers launched a multi-year project to explore effective methods for protecting vegetation, including wild rice in northern Minnesota lakes, from the invasive crustacean. There are 30 known lakes in Minnesota with populations of rusty crayfish, which are bigger and more aggressive than the native populations.

With a short field season, the NRRI researchers chose three lakes to focus their efforts on, located in the areas surrounding Ely, Isabella, and Lutsen.

In Cook County, both Caribou Lake and Pike Lake have confirmed populations of rusty crayfish. Caribou Lake was chosen as the focus site for the NRRI rusty crayfish project.

Brennan Pederson, the rusty crayfish project manager, said the team of researchers tested three different trap and bait types on each of the three lakes. The researchers tested two different-sized minnow traps and a refuge trap made of PVC tubes with an open end. The refuge trap was designed to attract female crayfish carrying eggs and provided a dark hiding place for the crayfish.

Trap full of Crayfish | Photo by MAISRC Ethan O’Brien

In addition to hot dogs, NRRI researchers tested wet cat food and frozen smelt as bait. Brady, Pederson, and their team found that all three options were similarly effective. However, the goal was to identify the most practical and widely available bait so that local residents and lake property owners could easily use the method themselves.

“So that’s what we’re going to recommend people or anybody who’s interested in trapping rusty crayfish they use,” Pederson said. “They should use plain hot dogs and a standard wire mesh minnow trap with funneled entrances.”

After finishing the research project, the NRRI published additional information and guides for residents and property owners to learn more about trapping rusty crayfish. Find it here.

WTIP’s Kalli Hawkins spoke with NRRI researchers Valerie Brady and Brennan Pederson about the rusty crayfish project, including the process, challenges, types of traps and bait, the best season to trap rusty crayfish, and more. The audio from the interview is below.  

Kalli Hawkins June 30, 2025