Atlantic Salmon
Salmo salar
Quick Facts
About the Species
Atlantic salmon in the United States were once native to almost every coastal river northeast of the Hudson River in New York. But dams, pollution, and overfishing reduced their population size until the fisheries closed in 1948. Currently, the only remaining wild populations of U.S. Atlantic salmon are found in a few rivers in Maine.
Commercial and recreational fishing for Atlantic salmon in the United States is prohibited. Only farm-raised Atlantic salmon are found in U.S. seafood markets. All Atlantic salmon in the public market is cultured and commercially grown.
Atlantic salmon in the United States were once native to almost every coastal river northeast of the Hudson River in New York. But dams, pollution, and overfishing reduced their population size until the fisheries closed in 1948. Currently, the only remaining wild populations of U.S. Atlantic salmon are found in a few rivers in Maine. These remaining populations comprise the Gulf of Maine distinct population segment (DPS), which is listed as endangered under the Endangered Species Act. In addition, the Gulf of Maine DPS is one of eight Species in the Spotlight. This means that NOAA Fisheries has made it a priority to focus recovery efforts on research to better understand the major threats and stabilize the Gulf of Maine DPS by improving access to quality habitat and thus, preventing its extinction.
Our dedicated scientists and partners use a variety of innovative techniques to conserve Atlantic salmon and to protect and rebuild depleted endangered populations. NOAA Fisheries also works with partners to protect federally designated critical habitat for Atlantic salmon and makes every effort to engage the public in conservation efforts. Learn more about protected Atlantic salmon.
Appearance
Atlantic salmon have a spindle-like body shape—rounded, broad in the middle, and tapered at each end. The shape is somewhat flattened toward the sides, which is typical of salmon species. The head is relatively small, about one-fifth of the body length. The underside paired fins are prominent, especially on juveniles.
While in freshwater, young Atlantic salmon—known as parr—have brown to bronze-colored bodies with dark vertical bars and red and black spots. These markings camouflage and protect them from predators. Once young salmon are ready to migrate to the ocean, their appearance changes; their vertical barring disappears and they become silvery with nearly black backs and white bellies. When adults return to freshwater to spawn, they are very bright silver. After entering the river, they will again darken to a bronze color before spawning in the fall. After spawning, adults—now called kelts—can darken further and are often referred to as black salmon. Once adults return to the ocean, they revert to their counter-shaded coloration dominated by silver.
Typically, an Atlantic salmon returning to U.S. waters will be 4 years old, having spent 2 years in freshwater and 2 years at sea. These fish are called “two sea winter fish,” or 2SW, and are usually 28 to 30 inches long and 8 to 12 pounds. The size of adults returning to freshwater from the ocean depends on how long they lived at sea. Young salmon returning to freshwater after 1 year at sea (known as “grilse” or 1SW) are smaller than 2SW adults. Adult salmon can migrate several times to spawn—a reproductive strategy known as iteroparity—though repeat spawners are becoming increasingly rare.
Biology
Atlantic salmon are migratory. They travel long distances from the headwaters of rivers to the Atlantic Ocean before returning to their natal rivers. For example, U.S. salmon leave Maine rivers in the spring and reach the seas off Newfoundland and Labrador, Canada, by mid-summer. They spend their first winter at sea south of Greenland and their second growing season at sea off the coast of West Greenland and sometimes East Greenland. Maturing fish travel back to their native rivers in Maine to spawn after 1 to 3 years. Unlike the Pacific salmon species, Atlantic salmon do not die after spawning, and adults can repeat the breeding cycle. They live for 4 to 6 years.
Females lay an average of 7,500 eggs in gravel nests, called redds. Eggs incubate slowly due to cold winter water temperatures, and about 9 to 20 percent of the eggs survive to the fry stage. Fry remain buried in the gravel for about 6 weeks and emerge in mid-May, when they quickly disperse from the redds and develop camouflaging stripes along their sides, entering the parr stage. Parr eventually undergo a physiological transformation called smoltification that prepares them for life in a marine habitat. During smoltification, fish imprint on the chemical nature of the stream or river to enable them to find their way back to where they were born. After smoltfication is complete in the spring, smolts migrate to the ocean to grow, feed, and mature.
Atlantic salmon growth rates are variable and depend on several factors including season, habitat quality, age, sex, and population density. They grow much faster in saltwater than in freshwater. After 2 years at sea, adult salmon can grow to an average length of 28 to 30 inches and weight of 8 to 12 pounds.
The diet of Atlantic salmon depends on their age. Young salmon eat insects, invertebrates while in freshwater, and plankton while at sea. Larger adult Atlantic salmon mainly prey on fish such as Atlantic herring, alewife, rainbow smelt, capelin, mummichogs, sand lances, flatfish, and small Atlantic mackerel. Birds, marine mammals, and fish prey on Atlantic salmon.
Where They Live
Range
Atlantic salmon are the only salmon native to the Atlantic Ocean. There are three groups of Atlantic salmon: North American, European, and Baltic. These groups are found in the waters of North America, Iceland, Greenland, Europe, and Russia. The North American group, including the Canadian and U.S. populations, was historically found from northern Quebec southeast to Newfoundland and southwest to Long Island Sound. In Canada, healthy populations still exist today, however, many populations are severely depleted.
In the United States, Atlantic salmon were once native to almost every river north of the Hudson River. Due to the effects of industrial and agricultural development (including habitat destruction, dams, and historic overfishing), most populations native to New England were eradicated. Now, the only native populations of Atlantic salmon in the United States are found in Maine. The GOM DPS at listing included the nine remnant populations in central and eastern Maine.
River specific populations in Maine still persist in the Sheepscot, Penobscot (including the Ducktrap), Narraguagus, Pleasant, Machias, East Machias, and Dennys rivers. GOM salmon leave Maine rivers in the spring and reach the seas off Newfoundland and Labrador, Canada, by mid-summer. They spend their first winter at sea south of Greenland and their second growing season at sea off the coast of West Greenland and sometimes East Greenland. Maturing fish travel back to their native rivers in Maine to spawn after 1 to 3 years.
Habitat
Atlantic salmon are anadromous—they leave the ocean to return to freshwater streams and rivers to breed. Atlantic salmon spawn in the coastal rivers of northeastern North America, Iceland, Europe, and northwestern Russia. After spawning, they migrate through various portions of the North Atlantic Ocean.
After hatching, young Atlantic salmon (called parr) remain in rivers or streams for the first 1 to 2 years of life, preferring shallow, cool, fast-flowing water with shade. After this period, the salmon migrate to open ocean waters where they spend about 2 to 3 years feeding, then return to their natal streams or rivers to spawn during the fall.
Scientific Classification
Atlantic salmon are the only salmon native to the Atlantic Ocean. There are three groups of Atlantic salmon: North American, European, and Baltic. These groups are found in the waters of North America, Iceland, Greenland, Europe, and Russia. The North American group, including the Canadian and U.S. populations, was historically found from northern Quebec southeast to Newfoundland and southwest to Long Island Sound. In Canada, healthy populations still exist today, however, many populations are severely depleted.
In the United States, Atlantic salmon were once native to almost every river north of the Hudson River. Due to the effects of industrial and agricultural development (including habitat destruction, dams, and historic overfishing), most populations native to New England were eradicated. Now, the only native populations of Atlantic salmon in the United States are found in Maine. The GOM DPS at listing included the nine remnant populations in central and eastern Maine.
River specific populations in Maine still persist in the Sheepscot, Penobscot (including the Ducktrap), Narraguagus, Pleasant, Machias, East Machias, and Dennys rivers. GOM salmon leave Maine rivers in the spring and reach the seas off Newfoundland and Labrador, Canada, by mid-summer. They spend their first winter at sea south of Greenland and their second growing season at sea off the coast of West Greenland and sometimes East Greenland. Maturing fish travel back to their native rivers in Maine to spawn after 1 to 3 years.
Atlantic salmon are anadromous—they leave the ocean to return to freshwater streams and rivers to breed. Atlantic salmon spawn in the coastal rivers of northeastern North America, Iceland, Europe, and northwestern Russia. After spawning, they migrate through various portions of the North Atlantic Ocean.
After hatching, young Atlantic salmon (called parr) remain in rivers or streams for the first 1 to 2 years of life, preferring shallow, cool, fast-flowing water with shade. After this period, the salmon migrate to open ocean waters where they spend about 2 to 3 years feeding, then return to their natal streams or rivers to spawn during the fall.
Scientific Classification
Kingdom | Animalia | Phylum | Chordata | Class | Actinopterygii | Order | Salmoniformes | Family | Salmonidae | Genus | Salmo | Species | salar |
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Featured News
Seafood Facts
Is Atlantic Salmon Sustainable?
U.S. farmed Atlantic salmon is a smart seafood choice because it is grown and harvested under U.S. state and federal regulations. Commercial and recreational fishing for Atlantic salmon in the United States is prohibited.
Availability
Wild-caught Atlantic salmon is not available. Farm-raised Atlantic salmon is available year-round.
Source
Atlantic salmon found in the market is from coastal salmon farms, mostly in Maine or Washington. Commercial and recreational fishing for Atlantic salmon in the United States is prohibited.
Taste
Buttery, rich taste.
Texture
Firm and fatty, rich in omega-3 fatty acids.
Color
Like wild-caught salmon, the flesh is reddish-orange or pink.
Health Benefits
Farmed salmon is low in sodium and contains high levels of omega-3 fatty acids and vitamin B12.
Nutrition Facts
Servings: 1; Serving Weight: 100 g (raw); Calories: 142; Protein: 19.84 g; Total Fat: 6.34 g; Total Saturated Fatty Acids: 0.981 g; Carbohydrate: 0 g; Total Sugars: 0 g; Total Dietary Fiber: 0 g; Cholesterol: 55 mg; Selenium: 36.5 mcg; Sodium: 44 mgMore Information
Seafood News
Aquaculture
Only farm-raised Atlantic salmon are found in U.S. seafood markets. U.S. farmed Atlantic salmon is a smart seafood choice because it is sustainably managed and responsibly harvested under U.S. regulations.
Commercial fishing for Atlantic salmon in the United States is prohibited. The Gulf of Maine distinct population segment (DPS) of Atlantic salmon are protected under the Endangered Species Act.
Environmental Impact
Federal and state regulations and monitoring requirements ensure that salmon farming (as practiced in the United States) has minimal impact on the environment.
Feeds
Farmed salmon are incredibly efficient at converting feed to edible protein. Alternative feeds have been developed to reduce the amount of fish meal and fish oil from forage fish.
Farming Methods
Atlantic salmon are spawned and raised in on-land hatcheries until large enough for transfer to net-pens in coastal waters.
Human Health
Atlantic salmon are rich in omega-3 fatty acids. They are not fed or injected with dyes. Antibiotic use is strictly limited in the United States and is prescribed only on a case-by-case basis by an on-site veterinarian.
Management
Permitting for salmon aquaculture is governed by federal, state and local governments. The federal agencies involved are NOAA, the Army Corps of Engineers, U.S. Fish & Wildlife Service, U.S. Department of Agriculture, the Environmental Protection Agency, the Food and Drug Administration, the Bureau of Ocean Energy Management, and the Coast Guard.
Salmon farms must adhere to federal regulations including those in the Magnuson-Stevens Fishery Conservation & Management Act, the Endangered Species Act, the National Environmental Policy Act, the Clean Water Act, and the Marine Mammal Protection Act.
Farming Methods
Atlantic salmon are spawned and raised in on-land hatcheries until large enough for transfer to net-pens in coastal waters.
Feeds
Farmed salmon are incredibly efficient at converting feed to edible protein. Alternative feeds have been developed to reduce the amount of fish meal and fish oil from forage fish.
Environmental Considerations
Water Quality and Benthic Impacts
Impacts to the environment can occur around fish farms when organic nutrients from uneaten food and fish waste exceed the capacity of the ecosystem to assimilate them. Potential environmental impacts are largely avoided with proper farm siting, husbandry, management, and modern technologies. Modeling interactions of farms and the environment can help guide decisions about siting locations.
Water Quality
Fish farms in the United States are required to meet waste discharge standards under the Clean Water Act. When farms are sited in well-flushed water, nutrient enrichment in the water column is generally not detectable.
Benthic Impacts
Proper siting in well-flushed erosional sea floors, and practices such as fallowing, control the impact of fish farms on the benthic environment.
Escapes
On rare occasions farmed fish escape and can possibly interact with their wild counterparts. Federal and state permits require containment management systems at all marine sites. NOAA is using models to understand the risk of escaped fish affecting the genetic diversity of wild populations.
Animal Health
Management and Remedies
Fish diseases occur naturally in the wild, but their effects go unnoticed because dead fish quickly become prey. Vaccines, probiotics, limiting farming density, high-quality diets, and controlled use of antibiotics prevent bacterial diseases in fish. Management of viral infections occurs through thorough monitoring, healthy culture conditions, low stress environments, and good nutrition and genetics.
Parasites are controlled on farms using therapeutants, fallowing farm sites, and pest management such as the use of cleaner wrasses. Most states have comprehensive aquatic animal health regulations, such as routine health exams by veterinarians.
Antibiotic Use
In the United States, antibiotics may only be used to treat bacterial infections in marine fish under direction of a veterinarian on a case-by-case basis. Antibiotics are considered a method of last resort and cannot be preemptively fed to fish. Special permits obtained from the Food & Drug Administration may be required. Vaccines have been effective in reducing, and in some cases eliminating, the need for antibiotics.
Human Health
Contaminants
Aquaculture feed is regulated and monitored by the FDA and state agencies to ensure feeds are not contaminated with heavy metals or methyl mercury. Both wild and farmed seafood contain low levels of polychlorinated biphenyls (PCBs). PCB levels in farmed salmon are orders of magnitude below the FDA lower limit.
Farmed Atlantic salmon is low in sodium and contains high levels of omega-3 fatty acids and vitamin B12.
Science Overview
NOAA Fisheries conducts various research activities on the biology, behavior, and population health of Atlantic salmon. The results of this research are used to inform management decisions for this species.
For detailed information about stock status, management, assessments, and resource trends, you can search for Atlantic salmon, and any other species of interest, using NOAA’s StockSMART web tool.
Researching Atlantic Salmon in Maine
For salmon in Maine, most current research focuses on two priorities – the impact of dams on populations and survival of salmon in the ocean.
Atlantic salmon may be facing new challenges in the Gulf of Maine due to changing environmental conditions. Increasing numbers of hatchery-raised Atlantic salmon smolts are entering the ocean via the Gulf of Maine, but fewer are returning to spawn, raising questions as to what is happening to these fish at sea. A 2011 study co-authored by a NOAA Northeast Fisheries Science Center researcher suggests that changing spring wind patterns, warming sea surface temperatures, and new predators along altered migration routes are affecting the survival of Atlantic salmon.
Learn more about Atlantic salmon research
Aquaculture Research
Alternative Feeds
NOAA and USDA launched the Alternative Feeds Initiative in 2007 to identify alternative ingredients to fishmeal and fish oil in aquaculture feeds. NOAA's Northwest Fisheries Science Center Aquaculture Program has been investigating production and use of alternative feed ingredients, processing fish waste, determination of nutrient requirements, and alternative lipid sources.
Growth & Reproduction
NOAA's Northwest Fisheries Science Center (NWFSC) has been exploring larval fish physiology and nutrition. The NWFSC uses genetics to understand how fish grow, resist disease, and mature.
Genetics & Genomics
NOAA’s Southwest Fisheries Science Center has been using genetics and genomics to evaluate broodstock selection and investigate how genetics of reared fish relate to health and fitness.
NOAA Fisheries and partners developed the OMEGA Model which is being used to address the genetic and ecological effects of escaped fish on wild fish of the same species.
Nutrient Impacts
The National Ocean Service’s CAPP Program assesses aquaculture environmental interactions and develops spatial planning and ecoforecasting tools.
NOAA works with academic partners and fishermen in New Hampshire to grow steelhead trout using Integrated Multi-Trophic Aquaculture, which allows multiple marine species to grow at the same time within and around a single structure. Net pens of steelhead trout are surrounded by blue mussels and sugar kelp, which absorb nitrogen waste released by the trout, resulting in a net removal of nutrients from the water column.
More Information
- Atlantic Salmon Ecosystems Research
- Protecting Endangered Atlantic Salmon in New England
- Atlantic Salmon Population Monitoring and Stock Assessment
- Atlantic Salmon and Ocean Ecology
- Learning About Atlantic Salmon in Greenland via Satellite Tags
- International Salmon Research
- U.S. Fish and Wildlife Service Northeast Fishery Center
Recent Science Blogs
Documents
Recovering Threatened and Endangered Species Report to Congress (FY 2021-2022)
This Report to Congress summarizes efforts to recover all transnational and domestic species under…
Atlantic Salmon Assessments
The U.S. Atlantic Salmon Assessment Committee monitors the population status of U.S. Atlantic…
2022 Report: Collaborative Management Strategy for the Gulf of Maine Atlantic Salmon Recovery Program
2022 report of the 2021 CMS committee activities
Guidance Document: Collaborative Management Strategy for the Gulf of Maine Atlantic Salmon Recovery Program
The strategy establishes a system of governance that describes the working relationships between…
Data & Maps
U.S. Atlantic Salmon Assessment Committee Database
This database contains historic adult return, adult stocking, juvenile stocking, egg production,…
Recovery Action Database
Tracks the implementation of recovery actions from Endangered Species Act (ESA) recovery plans.
Research
Farm Raised Salmon Letter of Authorization (LOA)
This Letter of Authorization (LOA) allows any federally permitted aquaculture company to possess farmed Atlantic Salmon in the Exclusive Economic Zone (EEZ).
Atlantic Salmon Research: An Ecosystem Approach
Salmon habitats are complex and support multiple species. We work across these systems and fish communities to better inform conservation efforts.
Priorities for Atlantic Salmon Habitat Restoration Partnership Grants
The following information relates to the FY2021 Atlantic Salmon Habitat Restoration Partnership Grants, published by the NOAA Restoration Center. Please refer to the funding opportunity for a full description of program priorities and evaluation criteria.
Frequent Questions: Atlantic Salmon Habitat Restoration Partnership Grants
Find answers to frequent questions about the Atlantic Salmon Habitat Restoration Partnership Grants.
Outreach & Education
Sea-Run,Go! Wild Atlantic Salmon
In this lesson students will use the Agents of Discovery™ app on their mobile devices to learn…
Outreach & Education
Sea-Run,Go! Wild Atlantic Salmon
In this lesson students will use the Agents of Discovery™ app on their mobile devices to learn…