20-8-2023 ULLAL DE BALDOVI, ALBUFERA - RED SWAMP CRAYFISH (Procambarus clarkii)

Procambarus clarkii, known variously as the red swamp crayfish, Louisiana crawfish or mudbug,[3] is a species of cambarid crayfish native to freshwater bodies of northern Mexico, and southern and southeastern United States, but also introduced elsewhere (both in North America and other continents), where it is often an invasive pest.

The native range of P. clarkii is from northern Mexico and far southeastern New Mexico, through the Gulf States to the Florida Panhandle, as well as inland north through the Mississippi Basin to southern Illinois and Ohio. It has also been introduced, sometimes deliberately, outside its natural range to countries in Asia, Africa, Europe and elsewhere in the Americas. In northern Europe, the populations are self-maintaining but not expanding, while in southern Europe, P. clarkii is multiplying and actively colonizing new territories at the expense of the native crayfish, Astacus astacus and Austropotamobius spp. Individuals are reported to be able to cross many miles of relatively dry ground, especially in wet seasons, although the aquarium trade and anglers may have hastened the spread in some areas (anglers using P. clarkii as fishing bait are thought to have introduced it to the state of Washington). Attempts have also been made to use P. clarkii as a biological control organism, to reduce levels of the snails involved in the lifecycle of schistosomiasis, leading to the dispersal of P. clarkii in, for instance, Kenya.

 P. clarkii has also been introduced elsewhere for cultivation, such as Spain, where its success is attributable to its ability to colonize disturbed habitats that would be unsuitable for the native crayfish (Astacus astacus). P. clarkii is also marketed by biological supply companies for teaching and research. P. clarkii also exhibits different colour morphs, including white, blue and orange, which are commonly sold in pet stores.

The introduction of P. clarkii has also resulted in economic losses in some regions. In the Baixo Mondego region of Portugal, it caused a decrease in 6.3% of profits in rice fields. However, this was on a wet-seeded field. All negative effects of crayfish can be avoided if adult crayfish are separated from the seed and seedlings.