The red swamp crayfish is native to Louisiana. The crayfish have been introduced in many countries, like China and Spain, to farm and this was such an economic success that China has become the largest producer of crayfish worldwide. The drawback is that the crayfish have escaped on a large scale and spread to the environment and has even become a pest in Europe and China.
Crayfish often don’t need feeding in ponds because they can find the food themselves in the pond. The pond then only needs to be fertilized, so there is not wild-caught fish needed to let the crayfish grow, and that is sustainable. Currently however, additional food is sometimes used, which reduces the sustainability. Next to the escapes, the problem is that there is no or little data on the effect on the environment.