U.S. aquacultural production comprises the production of food fish, ornamental fish, baitfish, mollusks, crustaceans, aquatic plants and algae, and some reptiles such as alligators and turtles. These organisms are grown in a wide variety of climates, in either fresh or salt water, and use a number of different production systems.
The 2005 Census of Aquaculture reported farm-level sales of $1.1 billion. The catfish industry is the largest sector in U.S. aquaculture, accounting for over 40 percent of all sales. Catfish production is concentrated in Mississippi, Alabama, Arkansas, and Louisiana. Catfish are grown in open freshwater ponds.
Other major food fish species grown in the United States are trout, salmon, tilapia, hybrid striped bass, sturgeon, walleye, and yellow perch. With the exception of salmon, these fish are normally grown in open freshwater production systems. Salmon differ somewhat from other species, as they are hatched in fresh water and then later transferred to saltwater net-pens for final growout.
Nonfood species are baitfish and ornamental fish. Baitfish are produced in freshwater ponds, with Arkansas being the largest producer. Ornamental fish production covers a large number of species and a variety of growing environments, including fresh, salt, cold, and warm water.
Aside from fish, U.S. aquaculture also produces freshwater crawfish, mainly in Louisiana, and shrimp, in brackish ponds in South Carolina, Texas, and Hawaii. The industry also farm-raises mollusk species, such as abalone, oysters, clams, and mussels. Mollusks are grown in almost every coastal area of the United States and are produced using various systems.
Other species that fall under the definition of aquaculture include the farmed production of alligators (mostly in Florida and Louisiana), turtles, aquatic plants, and algae. Aquatic plant production includes edible varieties, as well as plants for use in wetland restoration projects. The best known algae produced in the United States is spirulina, which serves as a nutritional supplement and food additive and, also, as a feed component for pets and ornamental fish.