Invasive Species | Fish and Invertebrates

Invasive Crayfish

Invasive Crayfish

Spinycheek crayfish (Orconectes limosus) and the Virile crayfish (O. virilis).

French common name: Les écrevisses

New Brunswick has one native crayfish, the Appalachian brook crayfish (Cambarus bartoni),  and two introduced invasive crayfish species; Spinycheek crayfish (Orconectes limosus) and the Virile crayfish (O. virilis). Both of these invasive crayfish are expanding their range within NB and have impacts on our native crayfish and other aquatic species in an increasing number of lakes and rivers.

Problem:  

These invasive crayfish are very aggressive, and outcompete our native crayfish for food and resources, which impacts larger aquatic food webs. They can also impact native fish species by damaging aquatic vegetation necessary for reproduction and spawning. Invasive crayfish can also spread rapidly, as females produce large amounts of eggs every year and carry them under their tail to protect them from predation. 

Species identification:

Invasive crayfish are typically larger than our native crayfish, growing up to 55mm in length versus the native at 30 mm. Invasive crayfish also have distinct features not present in the native species including;  

  • Prominent spines on the side of the head  

  • A pair of brownish, greenish, or reddish spots on the top of the tail section (see photos in file) 

In general, invasive crayfish also have a longer point between their eyes (known as a rostrum) compared to the native species.

How it’s spread:  

Invasive crayfish have been introduced and spread throughout the province through live bait for sport fishing and other introductions into local waterbodies. It is important to remember Don’t Let it Loose, and never release invasive crayfish into local waterbodies. Be sure to only use appropriate live bait species, and dispose of any unused bait in a secure trash area at least 30 metres away from the shore before leaving a waterbody. See https://www.dfo-mpo.gc.ca/species-especes/ais-eae/prevention/index-eng.html for more information.

 

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