Red swamp crayfish

Procambarus clarkii


Photo credit: ©Trevor Renals
Procambarus clarkii
  • It is a red or red-brown crayfish, measuring up to 12 cm long, with a cylindrical body.
  • It has a granular carapace with marginal spines. Its chelae are long and narrow with bright red tubercles and spines.

Origin and Worldwide Distribution:
  • It is native to north-eastern Mexico and south-central USA. It has been introduced to Belgium, Cyprus, France, Germany, Italy, Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom.

Potential or Known Impacts:
  • It outcompetes the native European crayfish and transmits the crayfish plague Aphanomyces astaci.
  • It degrades riverbanks because of its burrowing activity.
  • It accumulates heavy metals and toxins produced by Cyanobacteria, and can transfer them to its consumers, including humans.

How could it get here?
  • Intentional introduced for aquaculture, but can spread also by anglers for local consumption, and as bait.
  • It is widely available in the aquarium trade.

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

Methods for Prevention:
  • Monitoring and surveying pathways of introduction.
  • Removal of use for live bait.
  • Report any 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