Chicago crayfish: Invasives and natives, options and possibilities, unabridged Q&A with Kevin Irons

The unabridged Q&A with Kevin Irons on what is right and wrong in dealing with native and invasive crayfish.

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A bag of red swamp crayfish, part of a collection from the North Shore Channel and North Branch of the Chicago River on July 31 by staff from Keller Lab of Loyola University. Credit: Dale Bowman

A bag of red swamp crayfish, part of a collection from the North Shore Channel and North Branch of the Chicago River on July 31 by staff from Keller Lab of Loyola University.

Dale Bowman

My column Saturday about an ongoing study of crayfish, especially invasive red swamp crayfish, by the Keller Lab at Loyola University drew much interest. So I reached Kevin Irons, the assistant fisheries chief for the Illinois Department of Natural Resources, who specializes in invasives.

Here is the unabridged version of the Q&A.

Even if you captured red swamp crayfish yourself, it is illegal to transport them live or use them as live bait, right?

‘‘Correct. They are not an approved aquatic life, so possession and transportation is not permitted. You can see in the fishing regs that any wild-caught live or dead bait can only be used in the waters where caught. Baitfishing rules are on pages 4-5 in the fishing regulations.”

Would it be legal to transport and use them as bait if they were dead?

‘‘No, it is only appropriate to use live or dead wild-caught bait in waters where captured. The regs (see crayfish regs below) do allow four species of crayfish to be used live in waters where captured.’’

Could people trap them for a crayfish boil, if they killed them right away?

“Yes, I saw some comments and cringed a bit, however. As you know the water/sediment quality in the topic of the story might be questionable. Yes you can eat them, I would not likely eat them due to other advisories for aquatic life from the water where captured e.g. signs posted along waterway, so, I guess it depends where they are caught. I would have little problem eating crayfish (moderate frequency/quantities) from Lake Michigan.”

What should people do if they capture a red swamp crayfish?

‘‘Certainly, I recommend eating them out of appropriate water. Like all of our aquatic life, I would suggest dispatching and placing on ice immediately to protect quality. These are quality bait and can be used in the water where captured but not transported.

‘‘If an angler does not want to harvest the crayfish, several photos from top, bottom and sides can be taken and sent to, or you can call (217) 785-8772. With either method . . . provide contacts so we can [follow up]. While we prefer nuisance/invasive species are removed, it is permitted to immediately return such to the waters where caught. Many prefer not to kill/harm any species, and this is OK.

‘‘Crayfish are available for bait at local bait stores. They follow regulations and sell bait that is appropriate for selling in Illinois under appropriate screenings and permits. Also, they sell some crayfish DEAD to prevent spread or introduction of crayfish species. Again, by working together, we can keep our waters great!’’

Considering red swamp crayfish are distinctive, I doubt people reporting they caught them from odd waters are misidentifying them. Are more around than we realize?

‘‘We are looking into that with [Loyola professor Reuben Keller] and others. Red swamp crayfish are native to Illinois, native in those waters in extreme southern Illinois. Crayfish, in general, are highly invasive outside their native ranges, so transport of any live wild bait, including crayfish, is not allowed. Certainly less work is done on crayfish than fisheries in the state, so it would not surprise me to see them pop up in various locations due to movement from these satellite populations or other bait/food introductions.

“Historically bait, science classes, pet stores, and sacks for crawfish boil were made up of red swamp crayfish but we are limiting these imports much more now due to our heightened awareness of the harm they can do. Clearly, reaching out to those dealers on Illinois regulations, so they too can BE A HERO – TRANSPORT ZERO. Populations start up with a ‘free-Willy’ event from these or escapees (unintentional). As I said, we all need to be working toward the same goal.

“Red swamps are invasive around the country and world. You can see the drainages in the US where native and individals (minimum) have been found:

What should people do if they catch or capture what they suspect is an invasive in an unusual area?

“There are many online resources these days, but if a strange known or unknown critter is caught, I recommend taking photos with your cellphone from many angles (top, bottom, sides, head). [Then email or call (217) 785-8772. Provide a name and contact.] We have so many species in Illinois—more than 115 fish species in our large rivers alone, many times it may be a case of mistaken identity. We have identified species this way and followed up with our biologists. The mores eyes out there the better!”

Speaking of online resources, the best basic guide for local crayfish is “Common Crayfishes of the Chicago Region.”

Crayfish regs

Here are the crayfish rules from page 6 of the fishing regulations:

CRAYFISH It is a violation of state law to import, possess, sell or use as bait LIVE Rusty Crayfish. The Rusty Crayfish may be distinguished by a dark rusty spot on both sides of the carapace (body) and a rusty-red band followed by a dark stripe on the large pincers (claws). Rusty Crayfish destroy aquatic vegetation and eat the eggs of various fishes, which negatively affects fish reproduction. DEAD Rusty Crayfish may be used as bait. Any species of crayfish not found on the Aquatic Life Approved Species List are illegal to import, possess, sell or use as bait LIVE within the State of Illinois. DEAD crayfish of any species, excluding endangered or threatened species, may be used as bait. Endangered or threatened species may NOT be taken for use as bait, LIVE or DEAD. The following crayfish species shall be allowed for use as LIVE bait in Illinois using legal sized cast nets, shad scoops, and minnow seines, provided that they are not sold or bartered: White River Crayfish Procambarus acutus, Papershell Crayfish Orconectes immunis, Northern Crayfish Orconectes virilis, Devil Crayfish Cambarus diogenes. Crayfish may be collected with traps of metal screen or hardware cloth, plastic, or nylon mesh or netting. Such traps may not be more than 24 inches in width or diameter or more than 36 inches in length nor use a mesh of more than 1/2 inch bar measurement. Each entrance aperture may not exceed 1 1/2 inches in diameter. If unattended, such devices must be tagged with the name,mailing address and phone number of the person operating the device. Crayfish collected in such devices may only be used on the waters where collected, may only be taken for personal use, and may not be sold or bartered. Collected crayfish may NOT be transported between water bodies LIVE or DEAD.


The Illinois Conservation Foundation finally released the free app Outdoor Illinois. Get it where you get your apps. For more, go to


The Blackhawk Field Archers’ 28th annual Traditional-Only Shoot is this weekend in Rockton. Contact David Lee at (708) 476-0305.

Stray cast

Is Indians pitcher Zach Plesac, a Sox fan as a youth, considered a native or an invasive? (Or just a dumbass?)

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