Unlike many harmful invasive species in Ontario, the Rusty Crayfish does not come from overseas, but rather from our neighbors to the south. The Rusty Crayfish is native to the Ohio River basin in the United States. This species was likely introduced to Ontario by anglers from other areas discarding the crayfish they were using as bait. Another possibility is that the Rusty Crayfish may also have been introduced by people who acquired them as pets or through the scientific supply trade.
Rusty Crayfish are commonly found in lakes, rivers, ponds, and streams with clay, silt, and gravel bottoms that contain rocks, logs, or other debris the crayfish can hide under. They eat large quantities of vegetation and their large size and aggressive nature helps protect them from being eaten by native fish. A single female with 200 fertilized eggs can start a new population in an area not previously colonized by the Rusty Crayfish. There is currently no practical way to remove this invasive species once it has been established.
The Rusty Crayfish was first recorded in Ontario in the early 1960’s from the Kawartha Lakes region. They can now be found throughout much of south-central and southeastern Ontario, including Manitoulin Island, the Magnetawan River, the Kawartha Lakes Basin, the Ottawa River Basin, and in northwestern Ontario.
Help Stop the SpreadOntario Invaders Species Account PDF