For the past three years, a new aquatic invasive species has been making waves in Michigan. Many of you have had this species as a classroom pet, eaten it at a buffet or perhaps used it as bait for fishing. If you guessed red swamp crayfish, you guessed right! When I mention red swamp crayfish (Procambarus clarkii), many friends and colleagues from the south chuckle and say that it is a good problem to have as they are tasty! However chuckles aside, this species poses some serious problems. Red swamp crayfish's native habitat occurs in Northern Mexico, Gulf Coast States and Mississippi River watershed. They prefer slow moving freshwater such as retention ponds, small lakes and golf ponds, and utilize burrows on land. They are generally 2-5 inches in length, but some larger ones have been found (a 7 inch long one was found in Michigan in 2017) with a triangular rostrum. Body color is hard to use an identifier as their color can range from dark red, black or brown, however,they do have bright red dots unlike native crayfish found in Michigan (see picture below). Their diet consists of vegetation, snails, fish and amphibians. They are problematic as they are very aggressive towards native crayfish (and each other), and will out-compete them for food and habitat. Their burrows can be to 3 feet deep, and can be identified by the chimneys nearby (large mounds of sand and soil by the hole). They create many burrows which will eventually result in bank destabilization and erosion. They have also been associated with cyanobacteria blooms and eutrophication. It is thought that they were introduced via people releasing the contents of their aquariums into ponds or rivers, classroom pet releases, escapees from outdoor seafood boils, and bait dumping. The state of Michigan banned the possession of live red swamp crayfish in 2013, and in July of 2018, DNR worked with the Canadian Border Patrol to seize 2000 pounds of live crayfish at the border! If you are interested in cooking with them, I have found pre-cooked red swamp crayfish in the frozen seafood section of our local grocery store. While red swamp crayfish really is a rather tasty problem, it is important to prevent this species from becoming established in the wild! If you see any crayfish that looks like the red swamp crayfish, please contact me at [email protected] or give me a call at (517) 395 - 2089. You can also report sightings at https://www.misin.msu.edu/report . If you can safely take a picture that clearly shows the claws and its back, that would be very helpful for identification purposes. For more information: DNR. 2020. Red swamp crayfish. https://www.michigan.gov/invasives/0,5664,7-324-68002_74188-367863--,00.html, Date Accessed: August 20, 2020 Smith, K. et al. 2018. Assessment of invasion risks for red swamp crayfish (Procambarus clarkii) in Michigan. Management of Biological Invasions. https://www.researchgate.net/profile/Seth_Herbst/publication/326271116_Assessment_of_invasion_risks_for_red_swamp_crayfish_Procambarus_Clarkii_in_Michigan_USA/links/5b435d3daca2728a0d6627e3/Assessment-of-invasion-risks-for-red-swamp-crayfish-Procambarus-Clarkii-in-Michigan-USA.pdf
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AuthorShikha Singh is the coordinator for the JLW CISMA. She has a BSc. in Biology from University of Western Ontario, and her master's and PhD at Michigan State University from the Dept. of Fisheries and Wildlife. Her areas of expertise include water quality, water policy, invasive species, education/outreach and public speaking. |