“The red crayfish”- this is one of the most popular crayfish, red-swamp crayfish (Procambarus clarkii). It is the most wide-spread crayfish in the world as well as in the USA. (Photo: Sujan Henkanaththegedara).
How many crayfish species occur here in the United States? Many people will say the red kind, the blue kind, the green kind and the brown kind…some may add a few more such as the green and brown kind and the red and brown kind.
Although the USA is the global hotspot for crayfish diversity and they are virtually everywhere in southeastern US, it is surprising how little general public knows about crayfish (except crayfish as a food!). North America harbors more than 80% of global crayfish diversity (385+ species) which is mainly concentrated in southeastern United States. Virginia has about 28 species excluding some potential new species.
One of the challenges of crayfish identification is they all look very similar. Typical identification process considers the habitat and morphology focusing on claw shape and size, carapace shape and structure, distribution of spines and tubercles together with color patterns. However, if you want to be certain on the identification of a crayfish species, you need to find a type I (reproductively active) male to look at their genital (gonopodia) morphology.
So next time you find a crayfish in your creek or lake, have a closer look!