Louisiana Crawfish

(Procambarus clarkii)

This is a very invasive freshwater species of shrimp imported from Louisiana.


Louisiana crawfish are originally from the marshy, river areas of South-Central North America. The species was imported for animal farming for food in many countries, thanks to its quick, prolific growth. Having escaped from the farms, it became naturalized and is found today throughout Italy, including the islands.


Adults have a brownish-red colour that makes them easy to recognize. They can be distinguished from European river shrimp due to the presence of a small spine at the base of their pincers. This is an omnivorous and voracious species, capable of causing serious damage to aquatic ecosystems by devouring the eggs of fish, amphibians, and aquatic insects, as well as algae and aquatic plants. It competes with native European freshwater crayfish (Austropotamobius pallipes) not present in the Reserve, and in contrast to the latter, it adapts very well to turbid, polluted water. As well, it is a healthy carrier of some diseases that are lethal to native species.


This species is widespread in Lombardy, especially in the plain, and it is not the only exotic shrimp in the area. Louisiana crawfish are found on the list of Alien Invasive Species of Union Concern approved by the European Commission, and are also on the blacklist of invasive animal species subject to monitoring, containment, or eradication annexed to Regional Law 10/2008.

Observation in the Torbiera Reserve 

They are abundant in the Reserve and subject to containment.

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