Farming fish is a form of agriculture. While it doesn’t involve soil and tillage, it does involve the raising of an animal species in a domesticated setting, for food. And like all livestock farming, it involves manure management, feeding, animal wellness and slaughter.
“Intensively selecting aquatic animals from the wild, in an attempt to farm them, as the wild populations we had could not sustain” the demand for seafood, began about 50 years ago, Dr. John Jensen, Professor Emeritus, Schools of Fisheries, Aquaculture and Aquatic Sciences, Auburn University said. “There are tremendous opportunities to grow fish in the U.S. Until recently, animals from out of the vast ocean satisfied our demand for seafood.”
Many ocean fish species collapsed in the 1980s, leading to attempts to farm fish. Today, 130 species of fish, crustaceans and mollusks are farmed. Farmed seafood production provides about 55 percent of the world’s seafood demand.
Fish species selected for aquaculture production are easily domesticated, taste good, respond to feeding, and grow fast, Dr. Jensen said, making them similar to sheep, goats, cows, pigs and chickens — traditional livestock species.
In the United States, imported seafood makes up over 90 percent of what we consume. Currently, the market demand for seafood in this country focuses on shrimp, salmon, tilapia, catfish and pangasius — a Chinese species, all of which can be farmed; plus pollock, crab, tuna, clams and cod.
Aquaculture, or the “breeding, rearing, and harvesting of plants and animals in all types of water,” can meet much of this demand, Dr. Terry Hanson, Agriculture Economist, Auburn University, said.
Aquaculture occurs in both marine and freshwater environments. Fish raised in aquaculture production aren’t all destined for the table, either. Fish are grown for sport, for ornamental uses, for their eggs and for bait. Restocking native populations for conservation is also a use for aquaculture products. The pharmacy, nutritional, and biotechnology industries also are markets for aquaculture products.
Aquaculture occurs in ponds, oceans, pens, tanks, cages and raceways. Even some marine species can be supported in recirculating systems, rather than in the ocean. In the United States, the East Coast accounts for 38 percent of marine aquaculture production. Freshwater species, dominated by catfish, are more often grown inland, in ponds or manmade water environments.
“We have a lot of room to grow,” Dr. Hanson said. With 1,300 food fish farms; 700 mollusk farm; 300 sport fish farms; 500 farms producing crustaceans; 150 growing bait fish; and 250 raising fish for the ornamental trade: the market has plenty of room for expansion.
New York, New Jersey and Pennsylvania produce a large amount of aquaculture products. Pennsylvania, along with Texas, are the first in catfish production, with New York and New Jersey close behind. The entire Northeast leads in trout production, and mollusk production is centered on the East and West coasts.
New York, New Hampshire and Massachusetts follow the Southeastern states and Gulf of Mexico region in crustacean farming. Maine is number one for salmon farming, and the Mid-Atlantic states, plus New York and Pennsylvania, are tops in striped bass production.
Aside from food use, the Northeast dominates in ornamental fish production, as well as bait fish and sport fish. New York is number one in sport fish production, with New Jersey, Pennsylvania, and Virginia following.
Feeding fish requires either fish meal or soybean meal. With the cost of fish meal rising, many farms are turning to soy. Amino acids are added to make the soybean ration complete. If feed ingredient prices are kept low, then production can more readily intensify, Dr. Hanson said.
Types of production systems
Low intensity systems are those based in the wild. Harvesting fish from natural environments progresses to stocking the fish. Adding fertility to the water intensifies production. Semi-intensive modes of production include using pens, tanks and ponds and feeding fish. When fish are completely fed, and raceways and cages are added, the entire system is controlled in an intensive aquaculture production system.
Today, aquaculture is intensifying, similar to the industrialization that occurred in chicken farming in the 1950s, Dr. Jesse Chappell, Auburn University, said. The move from pastures to chicken houses is the equivalent of the changes seen as aquaculture intensifies today.
“Advanced conservation of water and utilization of inputs in a more efficient way,” is the focus on today’s aquaculture,” he said. “Confinement of fed species coupled with the continuous removal of waste solids produced by the fish,” is the focus of production today.
Enhanced pond systems have allowed production to double, or more, while reducing production costs by 30-50 percent, he said. Fish are kept in raceways within the pond “like a river within a pond,” where the water is constantly moving. A white water system, using a blower, drives the water through the raceway units.
Manure is collected in a fixed raceway system, via vacuum suction. This is in operation 24 hours per day and is very efficient. In a floating floor raceway, the manure is collected at the bottom, rather than the end, of the raceway, by passive settling out of manure solids. The white water unit in these systems features a diffuser grid, which moves the water via a continuous blower system. The air rises and expands, and directs the flow of the water, while manure settles to the bottom.
Recirculating Aquaculture Systems (RAS) are the next step, making aquaculture technology today “akin to modern swine production,” Dr. Chappell said. Year-round production, a similar time frame to harvest, a focus on slaughter waste recovery and an emphasis on resource conservation are features of modern swine and modern aquaculture farming.
RAS will “emphasize resource conservation while minimizing risk and optimizing yield,” he said, resulting in a “fully integrated production system.”
Here, feed mills will be onsite, and the production, harvesting, processing and by-product recovery will all occur on the farm. Technology to collect waste nutrients, both solid and liquid, and to utilize these to produce methane, fertilize plants, or otherwise integrate them back into the production system will be key innovations, and no by-products will need to be exported.
Drs. Chappell, Hanson and Jensen presented this topic via a NRCS conservation webinar, available at www.conservationwebinars.net