Crawdads in Danger
Whether you call them crayfish, crawdads, or anything in between, a new assessment indicates that more than half of these freshwater species are at risk. Having completed a conservation assessment for all native crayfish north of Mexico, NatureServe zoologist Jay Cordeiro recently presented his work at a conference of the International Association of Astacology, an organization dedicated to the study, conservation, and wise use of freshwater crayfish.
The work was influenced by NatureServe’s successful collaborations with the American Fisheries Society (AFS) on conservation status assessments of North American freshwater organisms as well as with our Red List partner, the International Union for Conservation of Nature (IUCN). Working closely with IUCN on a recent Red List assessment of global crayfish biodiversity, we utilized our global conservation ranks, or G-ranks, which are developed and actively monitored by NatureServe and every network program in the United States and Canada.
|% Species at Risk|
|Ferns & allies||31|
Currently there are 356 native crayfish (excluding subspecies, forms, and varieties) in the United States and Canada. The study’s results indicate 53% are at risk, including three possibly extinct species: sooty crayfish (Pacifastacus nigrescens), sandhills crayfish (Procambarus angustatus), and carrollton crayfish (Procambarus connus). While these percentages are lower than freshwater mollusks—snails (74%) and mussels (70%)—they are high compared to other groups of organisms.
Cordeiro’s presentation of the assessment was well-received and generated both interest from symposium participants in NatureServe and our ranking methodology, which found a clear correspondence with the AFS ranks. Future studies will identify regional hotspots for crayfish species imperilment by examining the proportion of species-at-risk to total species in each state/province.