The rusty crayfish is one of approximately 350 crayfish species that can be found in North American waters.

Rusty crayfish as the name implies, have a brown body, and greenish-rusty coloured claws with dark black bands near the tip. The rusty crayfish has more robust claws and is larger than other native species of crayfish.

There are prominent rusty patches on either side of the carapace. On average, they are 10 cm/3.9 inches long, not including the claws.


Rusty crayfish are found in lakes, rivers, ponds and streams with adequate rock, log and debris cover. They prefer river/lake bottoms that consist of clay, silt and gravel. They are most active from spring to fall when temperatures are above 8°C. When the rusty crayfish reproduce, they can lay 50-575 eggs at one time.

Rusty crayfish are omnivores so they will eat anything but prefer high protein foods. They feed on aquatic plants, aquatic worms, snails, leeches, aquatic insects, decaying plants and animals, fish eggs and small fish.


Rusty crayfish originate from streams in the Ohio, Kentucky and Tennessee watersheds. Used as baitfish by anglers, these crayfish have invaded portions of Ontario, Minnesota, Wisconsin, New York, Vermont and Maine.

The first Ontario reports of this species were from the Kawartha Lakes in the early 1960s. Since then, rusty crayfish have become established in several areas of the southern and northwestern parts of the province.

Rusty Crayfish

The rusty crayfish is native to North America, but the problem with the crayfish occured when it was introduced outside of its native ecosystem. Its native distribution is small, contained to only a single watershed.

It is likely that the rusty crayfish was introduced as bait by non-resident fishermen with the first findings in Ontario as early as the 1960s. To the uninformed, these crayfish to do seem to pose a threat to any ecosystem.

The rusty crayfish is one of approximately 350 crayfish species that can be found in North American waters. However the problem is that native crayfish are at highest at-risk along with plants and animals. Many species are vulnerable, imperiled, critically imperiled or presumed extinct.