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.
Figure 1. A Rusty Crayfish. Photo credit: D. Watkinson, Government of Canada
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.
Rusty Crayfish are designated as an aquatic invasive species (AIS) in Manitoba.
It is illegal to:
Rusty Crayfish were found in:
A Rusty Crayfish distribution map of can be found here.
Rusty Crayfish were likely introduced by recreational anglers through an illegal bait bucket release.
Rusty Crayfish can be identified by their:
Figure 2. Rusty Crayfish can be identified by the above characteristics. Source: Minnesota Sea Grant.
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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.).
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.
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: