The marbled crayfish is a mutant species that clones itself
One way to get rid of this problem is if they taste good, market them to Asian restaurants.<p>Right now spicy crawfish boils are fashionable in China, and I'm pretty sure the other East/Southeast Asian countries like crawfish also.<p>Just like with jellyfish. Chinese people already eat jellyfish, so if there's an infestation of jellyfish in the ocean, figure out a way to eat that species. A billion people can really put a dent in any wild population.