Invasive crayfish
a virile crayfish next to a native crayfish
Crayfish in Virginia are all in the family Cambaridae. The two most common native species in the Rivanna watershed are Cambarus acuminatus and Cambarus longulus. However, there have been at least two sightings of an invasive crayfish, the virile crayfish (Orconectes virilis) in the Rivanna watershed. This invasive has also been found in the James River, New River and Potomac River watersheds.
The virile crayfish is native to Montana, Wyoming, the Upper Mississippi River, the Great Lakes drainages, and the Hudson River. It was probably introduced in Virginia as food and as bait.
The virile crayfish is much larger than native crayfish, and more aggressive. It tends to out-compete native crayfish, and can therefore become the dominant crayfish species in its habitat. In addition, virile crayfish can survive out of the water, and can move from stream to stream.
To help stop the spread of this invasive, you can:
- Report sightings of unusually large crayfish
- Responsibly dispose of unused bait when fishing
- Ask bait suppliers to avoid selling virile crayfish and other non-native crayfish
References
- Brian Watson, Virginia Department of Game and Inland Fisheries
- http://www.dnr.maryland.gov/streams/pubs/virile_crayfish_factsheet.pdf