Invasive Crayfish Are a Serious Problem in Missouri
Invasive crayfish (also called crawdads) displace crayfish species naturally found in bodies of water (“native” species). They introduce disease, hurt fishing, and harm aquatic ecosystems. Our best hope of controlling them is to prevent their introduction to new locations.
Here's what you can do:
- Fish with live crayfish only on the body of water where the crayfish were collected. (Read more below about how even native crayfish can become invasive if moved to new waters.)
- Do not release any live bait back into waters, including crayfish. The release to the wild of live crayfish or any other bait is a violation of the Wildlife Code of Missouri and can harm the very fish and bodies of water anglers care about.
- If you purchase crayfish for bait, use only northern crayfish (Orconectes virilis), also known as “virile” crayfish, from in-state sources for live bait.
Native Crayfish are Important
Crayfish play a vital role in water quality. They break down decaying material such as leaves, woody debris, grass and dead animals in streams and lakes, which help keep debris from clogging the water and which provides food for many other animals.
Crayfish also serve as prey for more than 200 species of insects, fish, amphibians, reptiles, birds and mammals. They are the desired food for many popular game fish and the most important food for smallmouth bass and goggle-eye.
No crayfish species is found statewide
Of the 35 known species of crayfish in Missouri, eight are found nowhere else in the world. Missouri has greater numbers of crayfish per area of water or “densities” than almost anywhere else in the world. Each species of crayfish occurs only in certain areas of Missouri that provide for its special requirements. No species of crayfish is “native” to the entire state.
Browse our Identifying Crayfish guide for detailed information on Missouri crayfish species, distribution, attributes, and other information.
“Native” crayfish become invasive when moved into new waters
Even crayfish naturally found in an area of Missouri can become invasive if they are moved to new areas of the state where they are not naturally found. These invasive crayfish tend to unbalance aquatic food chains by rapidly overpopulating waters where they have been introduced.
Invasive crayfish spread disease, hurt fishing, and harm aquatic ecosystems
Invasive crayfish out-compete crayfish naturally found in an area for food and habitat. Invasive crayfish can also spread disease when moved to new areas where they are not naturally found. When invasive crayfish populations explode, they over-consume aquatic insects, snails and other food sources that native crayfish and game fish, such as trout, bass, and catfish, depend on. Less food results in fewer and smaller game fish.
Population explosions of invasive crayfish also lead to the reduction or elimination of aquatic plant beds. These important habitats support insects and smaller fish that are food for game fish. They also serve as spawning and nursery habitats for game fish such as bass and sunfish.
As a result, crayfish invasions hurt fishing for Missouri’s million-plus anglers. Fishing in Missouri generates more than $2.1 billion dollars to state and local economies.
Crayfish invasions are happening in Missouri and in other states and countries
MDC has documented 25 crayfish invasions in the state. In all of them, the invading species were naturally found in some part of Missouri. In half of them, the invading species are one of the four native crayfish species currently allowed to be sold for live bait (northern or virile crayfish, White River crayfish, red swamp crayfish and papershell or calico crayfish).
Invasive crayfish have also caused serious problems in Arizona, California, Idaho, Iowa, Louisiana, Maryland, Michigan, Minnesota, Montana, New York, North Carolina, Pennsylvania, Utah, Washington, Wisconsin and Wyoming, along with parts of Africa, Canada, Europe, and in Japan.
Missouri's bait regulation is a step to prevent new invasions
The Conservation Commission approved the commercial sales of only northern crayfish (Orconectes virilis), also known as “virile” crayfish, from in-state sources for live bait, effective March 1, 2014.
The regulation limits the sale, purchase, and importation of other species of live crayfish in the state to human consumption, scientific research, or as food for confined animals kept by approved entities, such as research institutions, agencies or publicly owned zoos.
The regulation prohibits the importation, sale, or purchase of other species of live crayfish in the state for all other uses, such as fishing bait, pond stocking or as pets or pet food.
This regulation does not apply to other types of bait or to dead or preserved crayfish.
Other states already ban the sale, use or importation of live crayfish as bait to some degree. Those states include Arizona, Idaho, Maryland, Minnesota, Nevada, Oregon, Utah, Virginia, Washington, Wisconsin, and Wyoming. Arkansas and Pennsylvania are considering a ban.
MDC will focus on education about invasive crayfish
MDC will keep the 2014 regulation in place, and staff will focus on educating anglers, bait shops, and others about the problems invasive crayfish cause.
MDC has been communicating with businesses, anglers and others that may be affected by this regulation and is considering their concerns related to the issue.
MDC will continue to work with these stakeholders on solutions to the problem of invasive crayfish.
Missouri anglers may still catch and use live crayfish, but should not dump them
- Anglers may still harvest a maximum of 150 crayfish per day from Missouri waters and must be in possession of a valid fishing license to do so.
- Anglers are strongly encouraged to fish with live crayfish only on the body of water where the crayfish were collected.
- Anglers should not release any live bait back into waters, including crayfish.
The release to the wild of live crayfish or any other bait is a violation of the Wildlife Code of Missouri and can harm the very fish and bodies of water anglers care about.
Missouri's commercial fishers and CFM support the regulation
MDC surveys of commercial fishers showed that most (70 percent) of all 70 Missouri commercial fishers who use bait were either supportive of a regulation that would prohibit live crayfish bait sales and purchase, but still allow for anglers and commercial fishermen to catch and use their own live crayfish bait. The Conservation Federation of Missouri also supports the MDC crayfish regulation.
Sales of live crayfish are a small part of business for Missouri's baits shops, aquaculturists, and pet shops
MDC surveys of bait shops, aquaculturists, and pet shops showed that:
- About 30 percent of registered bait shops reported getting an average of 7 percent of their annual income from live crayfish sales, with 1 percent the most commonly reported value.
- Almost 30 percent of all registered Missouri aquaculturists reported getting an average of 4 percent of their annual income from live crayfish sales with 0–2 percent the most commonly reported values.
- Only about 10 percent of Missouri pet shops reported selling live crayfish, with those sales amounting to an average of 1 percent of their total annual income.
MDC’s estimation of economic impact to bait shops, pet shops, aquaculturists, and pet shops was based on survey responses provided by these three groups.