Virile crayfish

Orconectes virilis


Photo credit: ©Chris Lukhop 
Orconectes virilis
Common Names:
  • Virile crayfish

  • Freshwater lakes, ponds, rivers, streams, canals.

  • The virile crayfish is a chestnut to chocolate brown crayfish with a wine glass shaped light brown pattern, and is up to 12cm long. The claws are broad and the same colour as the body.

Origin and Worldwide Distribution:
  • The virile crayfish is native to North America, was imported to Europe for the aquarium trade.
  • It was first recorded in the wild in 2004 in the Netherlands and is now also present in the United Kingdom.
  • It is most likely to have been deliberately released into the wild due to the disposal of unwanted aquarium collections.

Potential or Known Impacts:
  • As with other invasive alien crayfish, the virile crayfish can spread very rapidly into new waterbodies due to its high reproductive rate and fast growth.
  • High population density impacts heavily on freshwater habitats since they consume massive quantities of food and disrupt the natural food chain.

How could it get here?
  • Through the pet trade and likely deliberately released due to unwanted aquarium collections.

Is it found in Ireland or Northern Ireland?
  • Not present in Ireland or Northern Ireland.

Methods for Prevention:
  • In view of the species’ strong invasive potential, a ban on keeping, including in aquaria, or releasing the species, a rapid eradication of any newly emerging populations, and the management of already established populations should prevent the species from spreading or being introduced to other areas or Member States. At present there is no easy or cost-effective way to control any of the non-native crayfish populations once they become established.
  • Record all sightings.

You can help by reporting any sightings:
Current Legislative Position (Listed on 03 August 2016)
  • This species must not intentionally be brought into the Union; kept; bred; transported to, from or within the United Kingdom, unless for the transportation to facilities in the context of eradication; placed on the market; used or exchanged; permitted to reproduce, grown or cultivated; or released into the environment.
For further queries, you can contact the Non Native Invasive Species Team in the Northern Ireland Environment Agency on 028 9056 9558.
Invasive Species Ireland

Invasive Species Ireland