Aquatic Invasive Species

Aquatic Invasive Species Banner
 

Rusty Crayfish (Faxonius rusticus)

What is a Rusty Crayfish?

Rusty Crayfish (Figure 1.) is a species of crayfish not native to Canada. They are native to the Ohio River Basin in the United States. 

Rusty Crayfish

Figure 1. A Rusty Crayfish. Photo credit: D. Watkinson, Government of Canada

Why are they an issue?

Rusty Crayfish are a concern to Manitoba because they:

Experience from other North American watersheds - especially those with larger-sized water bodies - indicate that once AIS establish, they are cost prohibitive to eradicate.


Prohibition

Rusty Crayfish are designated as an aquatic invasive species (AIS) in Manitoba.
It is illegal to:


Where are Rusty Crayfish found in Manitoba?

Rusty Crayfish were found in:


Distribution of Rusty Crayfish in Manitoba

A Rusty Crayfish distribution map of can be found here.


How did Rusty Crayfish get to Manitoba?

Rusty Crayfish were likely introduced by recreational anglers through an illegal bait bucket release.


How to identify Rusty Crayfish

Rusty Crayfish can be identified by their:


Figure 2. Rusty Crayfish can be identified by the above characteristics. Source: Minnesota Sea Grant.


How to tell the difference between native Northern Crayfish (Faxonius virilis) and a Rusty Crayfish?

O
Figure 3. Native, Northern Crayfish claws with no gap when claws are closed

O
Figure 4. Invasive, Rusty Crayfish claws with oval gap when claws are closed.


Figure 5. Northern Crayfish on top; Rusty Crayfish on bottom with noticeable rusty patch circled in orange. Photo credits: D. Watkinson, Government of Canada.


Northern Crayfish claws are usually blue and when closed there is no gap between the upper and lower claw portions (Figure 3.). Rusty Crayfish have an oval gap when their claws are closed (Figure 4.) as well as a rusty patch on their side (Figure 5.).


How to stop the spread of Rusty Crayfish in Manitoba

The most effective prevention is to stop the human-caused movement, introduction and spread of Rusty Crayfish. All surface water-users play a role in preventing the introduction and spread of Rusty Crayfish. Prevention is our best defense.

When Rusty Crayfish were found in Falcon Lake, the Manitoba government created a zero possession limit for crayfish (i.e., no crayfish can be in your possession) in 2008. Due to this requirement, there are no Aquatic Invasive Species Control Zones in place for this species.

Schedule A of the AIS Regulation specifies which crayfish species and in what condition it can be possessed in Manitoba. This stipulation is to allow for human consumption.

The AIS Open-water Season and Winter (Ice-covered) Season checklists are step-by-step resources that can help you prevent the spread of Zebra Mussels and comply with the Manitoba government’s AIS Regulation.

Set fines for AIS offences are in effect year-round.


What should I do if you see an AIS such as Rusty Crayfish?

If you see a Rusty Crayfish in a water body where they are not known to exist, note the location, take pictures and report to the Manitoba government’s AIS Unit by: