In the United States, crayfish production is strongly centered in Louisiana, with 93% of crayfish farms located in the state as of 2018. In 1987, Louisiana produced 90% of the crayfish harvested in the world, 70% of which were consumed locally. In 2007, the Louisiana crayfish harvest was about 54,800 tons, almost all of it from aquaculture. About 70–80% of crayfish produced in Louisiana are "Procambarus clarkii" (red swamp crawfish), with the remaining 20–30% being "Procambarus zonangulus" (white river crawfish). Optimum dietary nutritional requirement of freshwater crayfish, or crayfish nutrient specifications are now available for aquaculture feed producers