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Rusty Crayfish

Rusty crayfish, Orconectes rusticus, ID, photo by US Army Corps of Engineers

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Common Name: Rusty crayfish
Scientific Name: Orconectes rusticus
Origin: Southern United States

Description

The rusty crayfish has a dark brown body, distinguishable by dark, rusty spots on either side of the carapace. It has larger, more robust claws than other members of the same genus. The claws are grayish-green to reddish-brown with dark black bands on the tips. When closed, the claws have an oval gap in the middle. The move-able claw is smooth and S-shaped.

Habitat

Rusty crayfish inhabit lakes, ponds and streams, preferring areas with rocks, logs or other debris for shelter. Clay, silt, sand, gravel and rock all serve as suitable bottom types; however, O. rusticus prefers cobble habitat, which allows it to hide if necessary.

Threat

Rusty crayfish are opportunistic feeders. They are a very aggressive species that often displace native crayfish. Rusty crayfish also reduce aquatic plant diversity by destroying the plants as they feed. They can harm fish populations by eating fish eggs, reducing invertebrate prey, and through loss of habitat (aquatic plants).

Management

Many chemicals kill crayfish and some are even selective for crayfish; however, none are currently registered for crayfish control and none selectively kill rusty crayfish without killing other crayfish species. Intensive harvest will not eradicate crayfish, but may help reduce adult populations and minimize some impacts. The best method of control, however, is to prevent their introduction. Educating anglers, crayfish trappers, bait dealers, and teachers about the threats posed by rusty crayfish will help reduce the risk of spreading rusty crayfish to new areas.

Regional Distribution

Locally Common

WNY PRISM Priority

Tier 4-Local Control

Invasive Species Priorities – Tier Chart

Pathways

Rusty crayfish were introduced to New York through aquarium releases and use as bait.

Rusty crayfish are a prohibited species in New York State – for more information on Prohibited and Regulated Species, visit http://www.dec.ny.gov/animals/99141.html.