Lobster-like invasive species linked to ecosystem havoc now confirmed in Ontario

A lobster-like invasive species of crayfish has now been confirmed in Ontario, with officials warning of the potential long-term impacts on freshwater ecosystems in the event that the creature continues to spread and establish breeding populations.

The red swamp crayfish (Procambarus clarkii) is a highly adaptable and aggressive invasive species originally native to the southeastern United States, particularly the Gulf Coast region from Florida to Mexico and the Mississippi River to southern Illinois and Indiana.

The species has since been introduced to Europe and multiple other U.S. states, including the watershed of Lake Michigan and into the Sandusky Bay of Lake Erie in Ohio, according to the provincial government.

In Ontario, the "freshwater lobsters" are regulated as a prohibited invasive species under the Invasive Species Act, 2015, making it illegal to import, deposit, release, transport, breed, buy, sell, or trade them.

Photo: Davide Zanin Photography/Shutterstock.com

According to the Ontario Federation of Anglers and Hunters Membership (OFAH), the presence of red swamp crayfish is confirmed in Ontario, with a reproducing population in Tilbury and a localized population in  Lake Aquitaine, Mississauga.

The lobster-like creatures are typically found in various freshwater habitats with muddy or sandy bottoms and lots of organic debris. Their problematic nature is specifically tied to their adaptability, as red swamp crayfish can withstand a wide range of oxygen levels, temperature, pollution, and pH.

Their feeding behaviours are especially problematic for other species, as red swamp crayfish have the tendency to reduce the density of aquatic plants and decrease critical habitats. They're also known for over-consuming species like small fish, molluscs, and amphibians, as well as eggs and larvae.

Photo: Andre Muller/Shutterstock.com

Females have the capacity to carry between 100 and 500 fertilized eggs under their tails, allowing them to quickly establish their dominance in various ecosystems.

Red swamp crayfish can be identified by their dark red bodies, with an elongated head and claws. Adults typically reach between five and 13 centimetres in length, and have raised bright-red, white, or black spots that cover their bodies and claws.

The species is eaten across the world, including in the U.S. (particularly in Louisiana), China, Cambodia, the Caribbean, Australia, and Africa, and has been used as bait by some anglers.

To prevent its spread, the provincial government notes that you should never buy, keep, or breed the species as a pet, and illegal activity should be reported immediately.