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Revised March 2022
Although most trout aquaculture in the U.S. involves the rainbow trout (Oncorhynchus mykiss), there are two additional species of commercial importance. Brook trout (Salvelinus fontinalis) have a natural distribution that includes northeastern North America from the Atlantic seaboard south to Cape Cod, the Appalachian Mountains southward to Georgia, westward to the upper Mississippi and Great Lakes drainages in Minnesota and northward to the Hudson Bay. Their range has been greatly expanded over the past two centuries through artificial propagation and introductions.
The natural distribution of brown trout (Salmo trutta) includes Iceland, the British Isles and the Eurasian mainland from Cape Kanin to the Aral Sea and Afghanistan westward throughout Europe. As a prized sport fish, brown trout have also been widely introduced into many parts of the world. As a result of stocking efforts beginning in the late 1800s, they are widely established throughout North America.
Brook trout and Brown trout are raised in large quantities by state hatcheries for stocking into public lakes and streams. They also are cultured in private facilities for both recreational fishing on site and for stocking into private ponds. Additionally, they can be found in the supermarket and restaurant trade as a food fish. These are cold water species, with production facilities and consumer demand somewhat limited geographically to northerly and/or high-altitude regions.
Rainbow trout are the most popular and easily reared trout species. They are a fast-growing and crowding-tolerant fish, making them well suited to captive breeding. These trout are widely used around the world for fish farming and restocking for recreational angling. In the wild they feed on invertebrates and other fish, but cultured strains do very well on a variety of artificial diets.
Genetic lines of rainbow trout in use today come from domestic strains developed to produce food size fish rapidly and efficiently under intensive farming conditions. The fish are purchased as fry by most small- to medium-size operations and reared to marketable size. In larger operations fry are often hatched in-house from eggs obtained from domesticated brood stock. Spawning begins in early spring as water temperatures approach 50°F. Eggs numbers may be as high as 12,000 per female. For optimal growth, temperatures should be maintained at about 59°F, and high protein diets are required. The pH should remain close to neutral, with an acceptable range of 6.7 to 8.2. Like most salmonid species, dissolved oxygen levels should remain above 5.0 ppm.
Like all trout, rainbow trout do best in cold, well-oxygenated waters. Like brown trout, however, they are much more tolerant of warmer temperatures than brook trout. They are capable of surviving temporarily in temperatures as high as 85°F, provided the water remains well-aerated. Most trout farms in the U.S. rely on gravity flow of spring water or cold water diverted from natural streams through tanks, ponds or rectangular concrete tanks built in a stair-step configuration (referred to as raceways). Raceways have become the system of choice for most producers, because they facilitate regular grading of the fish. As they grow, trout must be graded to reduce densities, optimize feed conversion and maintain more uniform lots of fish. Grading may be required as many as four times during grow-out.
The USDA 2018 Census of Agriculture reported that 334 trout-rearing farms were located in the U.S. that year. Total sales (eggs, broodfish, fry, fingerlings, stockers and food-size fish) totaled $116.7 million. Idaho reported $41.45 million in trout sales, the highest total of any state, from 21 farms. Washington ranked second with $26.15 million in sales, followed by North Carolina with $9.77 million, California with $7.38 million and Pennsylvania with $6.77 million. Altogether, 39 states reported trout aquaculture operations. The total value of food-size fish sold in 2018 totaled $95.9 million, followed by eggs ($10.6 million), stockers ($8.3 million), fingerlings and fry ($1.6 million) and brood fish ($322,000).
Although a downward trend was already apparent, pandemic effects appear to have severely impacted the U.S. trout industry during 2020. The total value of fish sales received by trout growers was down 13 percent over the prior year, totaling $94.6 million. The number of trout 12 inches and longer sold during 2020 totaled 25.4 million fish, down 20 percent from the previous year, although sales value of these fish, at $87.0 million, was down only 12 percent. The average price per pound was $1.97, a 2 percent increase from the previous year. Some 67 percent of these 12+ inch fish were sold to processors. In contrast, the major sales outlet for 6"-12" trout was for recreational stocking, accounting for 48 percent of total sales for this size class. The number of 6"- 12" trout sold during 2020 was also down, by 26 percent compared to 2019. The average price per pound was $3.54, down 11 percent from the 2019 price. As a result, the total value of sales for 6”-12” trout reflected a 24 percent decrease from the prior year. Similarly, the number and sales value of 1"- 6" trout sold during 2020 decreased by 17 percent and 26 percent, respectively.
Rainbow trout are typically offered for sale as fresh, fresh-frozen or smoked products sold in supermarkets and other retail outlets, live fish for the restocking of rivers and lakes for recreational fisheries, and products from hatcheries whose eggs and juveniles are sold to other farms. Marketable food-size fish size can be reached in 9 months, but 'pan-sized' fish (around 1 lb.), are harvested after 12 to 18 months. Optimal harvest size in the U.S. is generally considered to be 1.5 lb. Trout are marketed as fresh or frozen whole fish or fillets (often boneless) and as value-added products, such as smoked trout. When trout are reared for angling purposes, most are already at a harvestable size when transferred to public waters (“put-and-take fisheries”) or private ponds.
According to NOAA’s U.S. Trade in Fishery Products data, 17,944,842 kg (395,616,605 lb..) of trout products were imported into the U.S. in 2020, with a value of $163.8 million (an average of $4.14 per lb..) Major suppliers of imported trout, by value, were Chile ($60,238,503), Norway (57,850,381), Peru ($21,578,276), Colombia ($8,627,361) and Canada ($6,401,496). In spite of these volumes, the largest market for large farm raised trout available to U.S. producers is still processors. These processors compete directly with imports by offering fresh products and catering to buyers’ preferences for product sizes, regular delivery schedules and quality controls.
U.S. trout producers also sell significant quantities of large fish for recreational stocking, and directly to retail outlets and consumers. Government agencies, other producers and live haulers/brokers are also utilized to move larger size fish. In contrast, younger fish in the 6” – 12” range are sold primarily for recreational stocking, or to government agencies for stocking public waters, or to other producers for further grow-out. Lesser amounts are sold to processors, directly to consumers, live haulers/brokers and retail outlets.
Stocking and feeding rates determine (roughly) trout age and size at harvest. Having a number of raceways stocked at different densities may help generate regular harvests of uniform product. This, however, may also require a larger initial investment and the need to compete for market share with larger, established producers in order to justify investment costs. Successful trout farming depends on having access to a high-quality, reliable water supply. Flowing water must be available 24 hours a day, in sufficient volumes to maintain high oxygen levels and flush wastes away from the fish.
When planning a trout farming facility it will be necessary to calculate the carrying capacity of the system in order to estimate capital costs, projected production, revenues and input requirements. At this point, an evaluation can begin in order to determine if the operation will be large enough to generate profits and if so, a market analysis can be undertaken. These projections will also help determine if settling ponds or other measures will be required to reduce downstream environmental impacts from the farm discharge.
Markets must be available to accommodate your production when it is ready for harvest because maintaining trout beyond a harvestable size requires excessive feed, labor and energy costs as well as unproductive use of facilities and capital. If you will be farming on a large scale and selling to a processor, keep in mind that developing and maintaining committed relationships with both suppliers and buyers will be crucial. No matter what your scale of production will be, you will need to provide value through quality control, harvest scheduling and customer service. In turn your customers must also be willing to provide reliable outlets for your fish when you need to move them.
Accurate and detailed cost projections are essential when establishing a fish farming business. Projected costs (variable, fixed, marketing and opportunity costs) must be compared to prevailing market prices for the sizes and quality of the fish you intend to produce. Keep in mind economies of scale – a smaller operation will have higher per-fish costs and will require a number of small-volume, local markets that are willing and able to pay higher prices. When a small operation loses a customer, alternatives may be limited or nonexistent. Your input suppliers (feed, fingerlings and equipment) must be reliable and trustworthy, even when larger customers are competing with you. Consider your feed requirements – who will supply it, at what cost, and in what quantities will it be delivered? If buying in bags instead of bulk deliveries, your cost of production will automatically go up.
Small scale trout production may not be profitable without a competitive edge in local markets gained through accessibility, customer service and logistics. Fee fishing or on-site processing and sales may improve revenues, but these approaches usually involve excessive focus on permits, licenses and liability insurance. Nonetheless, any number of marketing campaigns can be developed with local retail partners ranging from in-store product demonstrations, to visits by local school groups, to targeted marketing through ethnic-oriented print and radio media that serve communities accustomed to purchasing live or fresh fish.
- Trout Production https://www.nass.usda.gov/Surveys/Guide_to_NASS_Surveys/Trout_Production/index.php USDA National Agricultural Statistics Service, 2021.
- U.S. Trout Farmers Association http://ustfa.org/
- USDA 2018 Census of Aquaculture. https://www.nass.usda.gov/Publications/AgCensus/2017/Online_Resources/Aquaculture/index.phpNational Agricultural Statistics Service, 2019.
- NFI’s Top 10 List Suggests Consumers Diversifying Seafood Consumption https://aboutseafood.com/press_release/nfis-top-10-list-suggests-consumers-diversifying-seafood-consumption/National Fisheries Institute, 2021.
- U.S. Trade in Fishery Products https://www.fisheries.noaa.gov/foss/f?p=215:2:10127503492079::NO::: National Oceanic and Atmospheric Administration, Washington D.C., 2021.
- Trout https://srac.tamu.edu/categories/view/34 Southern Regional Aquaculture Center, 2021.
- A profile of the aquaculture of trout in the U.S. https://freshwater-aquaculture.extension.org/wp-content/uploads/2019/08/Trout_Profile.pdf J. Hinshaw, G. Fornshell and R. Kinnunen, Freshwater-Aquaculture-Extension.org, 2021.
- Trout culture in the North Central region https://www.ncrac.org/files/biblio/ncrac108.pdf K. Cain and D. Garling, North Central Regional Aquaculture Center, 2019.
Revised by C. Greg Lutz, Louisiana State University Agricultural Center