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.
  • It could also have a major threat to native crayfish species by transmitting the crayfish plague.

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

Is it found in Northern Ireland?
  • Not present in 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: @ the Centre for Environmental Data & Recording (CEDaR) - Or via the iRecord App.
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 Invasive Non Native Species (INNS) Team in the Northern Ireland Environment Agency on 028 9056 9558 or Email:
Invasive Species Northern Ireland

Invasive Species Northern Ireland