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Atlantic Salmon
Atlantic Salmon Species Profile
Atlantic salmon are anadromous, which means they live in both fresh and saltwater. Commercial and recreational fishing for Atlantic salmon is prohibited and only farm-raised Atlantic salmon are found in U.S. seafood markets.
Atlantic Salmon
Salmo salar
Also Known As
Salmon, Sea run salmon, Kelts, Black salmon
Protected Status
ESA Endangered
Gulf of Maine DPS
Quick Facts
Weight
8 to 12 pounds, but may reach 30 pounds
Length
Up to 30 inches
Lifespan
4 to 6 years
Threats
Climate change,
Dams and culverts that block or impeded access to habitats,
Foreign fisheries,
Habitat degradation,
Low ocean survival
Region
New England/Mid-Atlantic
Atlantic salmon fish. Credit: Bob Michelson
Atlantic salmon fish. Credit: Bob Michelson
About the Species
Atlantic salmon fish. Credit: Bob Michelson
Atlantic salmon fish. Credit: Bob Michelson
Atlantic salmon, also known as the “King of Fish” are an iconic species of the Northeast and once supported fisheries throughout their range. Today, commercial and recreational fishing for Atlantic salmon in the United States is prohibited. All Atlantic salmon in the public market is cultured and commercially grown. Only farm-raised Atlantic salmon are found in U.S. seafood markets.
Atlantic salmon are migratory fish that hatch in freshwater rivers, migrate to the ocean where they mature, and then return to their natal freshwater rivers to spawn. This complex life cycle involves transitioning between different environments, requiring significant physiological adaptations to survive in both freshwater and saltwater habitats.
Atlantic salmon in the United States were once native to many coastal rivers 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 rivers in central and eastern 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 10 Species in the Spotlight. Species in the Spotlight is a NOAA Fisheries initiative to provide immediate, targeted actions to stabilize populations and prevent extinction of highly at-risk endangered species. The 2021–2025 Species in the Spotlight Action Plan for Atlantic Salmon indicates that in order to halt the decline of the GOM DPS, we need to prioritize recovery efforts that 1) increase habitat connectivity, 2) increase the number of smolts entering the marine environment, and 3) increase our understanding of and ability to improve marine survival.
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.
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.
Atlantic salmon change appearance throughout their life cycle to help them survive in different environments. While in freshwater, young Atlantic salmon 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 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.
Biology
Atlantic salmon have a complex life history and go through several stages that affect their behavior, appearance, and habitat needs.
Atlantic salmon begin their life cycle in rivers in Maine. Over several years they grow from eggs to fry to parr. After smolting, they travel through the Gulf of Maine into the North Atlantic as far as the coast of Greenland where they reach maturity before returning to Maine rivers to spawn. Credit: NOAA Fisheries
Migratory Behavior
Atlantic salmon are anadromous fish which means they live in both fresh and saltwater. Their life history begins with spawning and juvenile rearing in rivers; then migrating to saltwater to feed, grow, and mature before returning to freshwater to spawn. This behavior often requires traveling long distances from the headwaters of rivers to the Atlantic Ocean and back to their natal rivers. Mature salmon travel back to their natal rivers in Maine to spawn after 1 to 3 years in the ocean. U.S. salmon leave Maine rivers as smolts 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.
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. Young salmon returning to freshwater after 1 year at sea are known as “grilse” or 1SW.
Unlike the Pacific salmon species, Atlantic salmon do not necessarily die after spawning. Adult salmon can migrate several times to spawn—a reproductive strategy known as iteroparity—though repeat spawners are becoming increasingly rare.
Size and Growth
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 due to increased foraging opportunities (more fish and large invertebrates). 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 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 are smaller than 2SW adults and older sea-age fish and repeat spawners are larger.
Life Cycle
When spawning in the fall, the female salmon uses its tail to dig nests, called redds, in the gravel river beds where the eggs are deposited. Females lay an average of 7,500 eggs in these gravel nests which are called redds. Eggs incubate slowly due to the cold water temperatures. Over winter, the eggs hatch into very small salmon called alevin which still have their yolk sac attached. Alevins stay close to the redd for a few months hiding from predators in the spaces between gravel. During this stage they consume the yolk sac and grow in size.
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Atlantic salmon parr swimming. Photo Credit: Nick Hawkins
In the spring, the alevin emerge from the redd and enter the fry stage. Fry develop spots on their sides for camouflage and begin to feed on their own. Only about 15 to 35 percent of eggs laid will survive to the fry stage.
As the water temperature rises, the fry continue to feed and grow, transitioning into the parr stage. Parr are approximately 2 inches long and camouflaged with spots and vertical bars to protect them from predators. For 2 to 3 years, the parr grow in freshwater before transforming into a migratory stage called smolts. This physiological transformation is called smoltification and prepares the salmon for life in a saltwater marine environment.
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Hatchery salmon smolt
During smoltification, Atlantic salmon imprint on the chemical nature of their stream or river to enable them to find their way back to where they were born.
During this time, the now silvery-colored smolts’ gills and organs functionally change, allowing them to migrate into the ocean to grow, feed, and mature.
After 1 to 3 years at sea, adult Atlantic salmon return to the streams and rivers where they were born to lay and fertilize eggs. After spawning, these adults, now called kelts, swim back to the ocean to possibly return to spawn again in future years.
Salmon in the Food Web
The diet of Atlantic salmon depends on their age. Young salmon eat insects, invertebrates while in freshwater, and plankton while at sea. Larger adult salmon mainly prey on fish such as Atlantic herring, alewife, rainbow smelt, capelin, sand lances, and small Atlantic mackerel. Birds, marine mammals, and larger 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 Gulf of Maine DPS at listing included the nine remnant populations in central and eastern Maine, one of which is now locally extinct. River-specific populations in Maine still persist in the Sheepscot, Penobscot (including the Ducktrap), Narraguagus, Pleasant, Machias, East Machias, and Dennys rivers.
World map providing approximate representation of the Atlantic salmon's range.
Habitat
Atlantic salmon habitat requirements change throughout their lives from shallow, cold freshwater streams and rivers to the open ocean.
Parr habitat, often called "nursery habitat," refers to usually shallow areas in freshwater streams where the water breaks over rocks or gravel and flows quickly. Parr will also congregate around the mouths of small tributaries.
Smolt habitat refers to unobstructed riverine and estuarine habitat that allow salmon to physiologically transform as they migrate from a freshwater environment to a saltwater marine habitat.
Marine habitat refers to coastal oceanic habitat that Atlantic salmon migrate to after leaving rivers, where they feed heavily and grow rapidly. Marine habitat must provide abundant food resources and have good water quality and cold temperatures for salmon to thrive.
Adult spawning habitat refers to freshwater river and stream habitat with a gravel bottom where females can dig nests. Spawning habitats must have diverse pools, riffles, and runs because adults construct nests in locations with abundant dissolved oxygen.
Scientific Classification
Kingdom
Animalia
Phylum
Chordata
Class
Actinopterygii
Order
Salmoniformes
Family
Salmonidae
Genus
Salmo
Species
salar
Last updated by NOAA Fisheries on 04/01/2025
What We Do
Conservation & Management of Protected Species
We have a specific recovery plan for the Gulf of Maine DPS of Atlantic salmon to help rebuild the depleted and endangered population. The plan focuses on increasing the amount of accessible spawning and rearing habitat in freshwater and increasing the abundance of adult returns in each of the three geographically distinct recovery units. Targeted management actions include:
Improving connections between the ocean and freshwater habitats important for salmon recovery
Maintaining genetic diversity of Atlantic salmon populations over time
Increasing the number of reproducing adults through the conservation hatchery program
Increasing the number of reproducing adults through the freshwater production of smolts
Increasing Atlantic salmon survival by improving our understanding of marine ecosystems and the factors that affect salmon in the ocean
Collaborating with partners and involving interested parties in recovery efforts
Our research projects have discovered new aspects of Atlantic salmon biology, behavior, and ecology and helped us better understand the challenges that all Atlantic salmon face. This research is especially important in rebuilding depleted and endangered populations. Our work includes:
Performing stock assessments
Researching marine ecology in West Greenland
Tracking migration survival and ecology in estuaries and coastal oceans
Researching co-evolved fish
Modeling impacts of salmon upstream and downstream dam passage
Oyster growers harvest farmed shellfish from the Damariscotta River in Maine. NOAA has awarded several grants to small businesses working to develop new tools to advance sustainable U.S. aquaculture. (Image credit: C. Katalinas/ Maine Sea Grant)
Helicopter fitted with cameras for aerial mapping. The cameras are in the gray box mounted to the underside of the cockpit in front of the landing skids. Credit: Atlantic Salmon Federation/Valerie Ouellet
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.
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 mg
Farmed Atlantic salmon makes a delicious, healthy meal! If you need some cooking inspiration, browse these recipes for salmon sushi cups, easy pesto salmon, and more!
Last updated by NOAA Fisheries on 04/01/2025
Seafood News
Fresh-caught taʻape on ice. Credit: Conservation International Hawaiʻi.
NOAA Fisheries, in collaboration with Blue Ocean Mariculture, is conducting a multi-year pilot study to evaluate observational methods and tools for studying Hawaiian monk seal behavior. Courtesy of Blue Ocean Mariculture
The Gulf of Maine DPS of anadromous Atlantic salmon is one of NOAA Fisheries’ Species in the Spotlight. This initiative is a concerted, agency-wide effort launched in 2015 to spotlight and save the most highly at-risk marine species.
In the Spotlight
Gulf of Maine Distinct Population Segment of Atlantic Salmon
The Gulf of Maine DPS of anadromous Atlantic salmon is one of NOAA Fisheries’ Species in the Spotlight. This initiative is a concerted, agency-wide effort launched in 2015 to spotlight and save the most highly at-risk marine species.
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Atlantic salmon are an iconic species of the Northeast. They once returned by the hundreds of thousands to most major rivers along the northeastern United States, but now only return in small numbers to rivers in central and eastern Maine (Androscoggin to Dennys).
In the 1900s, Atlantic salmon from Maine were so highly valued that, for more than 80 years, the first one caught in the Penobscot River each spring was presented to the U.S. president. The last presidential salmon was caught in May 1992 because there are now too few adult salmon to sacrifice even one.
Atlantic salmon once supported lucrative commercial and recreational fisheries in New England. They were of great cultural and historical importance to Native American tribes in Maine, as well as a source of food. If this species goes extinct, the services it once provided to the American and Native American people will be lost.
The Gulf of Maine DPS of Atlantic salmon was initially listed as an endangered species in 2000. A subsequent rule issued by U.S. Fish and Wildlife Service and NOAA Fisheries in 2009 expanded the geographic range for the Gulf of Maine DPS to include the Penobscot, Kennebec, and Androscoggin Rivers.
Because of the rapid decline and dire status of the Gulf of Maine DPS, we and our partners have made it a priority to stabilize and prevent extinction of this iconic species.
Where Gulf of Maine Atlantic Salmon Live
Young salmon spend 2 to 3 years in the rivers and streams of Maine, then undergo physical changes to prepare them for life in the ocean. Once Gulf of Maine Atlantic salmon leave Maine streams and rivers, they migrate to the ocean. Some salmon return to Maine after their first winter at sea, but most spend a second year feeding in the Labrador Sea off the southwest coast of Greenland. Most Gulf of Maine salmon return to rivers in Maine after two winters at sea.
Population Status
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Atlantic salmon are endangered, with only a few runs remaining in Maine rivers.
The Gulf of Maine population of Atlantic salmon has declined significantly since the late 19th century. Historically, dams, overfishing, and pollution led to large declines in salmon abundance. Improvements in water quality and stocking from hatcheries helped rebuild populations to nearly 5,000 adults by 1985, but in the early 1990s there was a substantial decrease in marine survival that contributed to a significant population decline. Since 2015, annual returns to Gulf of Maine rivers have averaged less than 1,200. The rapid decline and dire status of the ESA-listed Gulf of Maine DPS makes it a priority for NOAA Fisheries and partners to prevent its extinction and promote its recovery.
Threats
Dams limit or block salmon access to important habitats in Maine. More than 90 percent of Maine's rivers and streams are affected by dams, which directly kill or injure a significant number of Atlantic salmon on upstream and downstream migrations. Dams also harm important habitats by flooding free-flowing rivers, reducing water quality, and changing fish communities. Finally, dams worsen the effects of climate change by limiting Atlantic salmon's access to cool-water habitats in higher elevation areas in Maine. Of the more than 400 dams along rivers and streams that support wild Atlantic salmon, only 75 have fishways, a structure that allows fish to swim around dams to reach their spawning grounds.
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Coopers Mill Dam in 2016 before dam removal by Atlantic Salmon Federation.
Gulf of Maine DPS salmon survival in the ocean has decreased over the last 25 years. This means that an increasing number of salmon die in the ocean before they can return to Maine to spawn. Many Atlantic salmon die in the ocean due to predation, starvation, diseases and parasites, and changing ocean conditions. Marine survival is poor throughout the Atlantic Ocean and is affected by both nearshore and open ocean survival rates. This ongoing and significant threat has pushed populations of Atlantic salmon in the United States closer to extinction. The North Atlantic Salmon Conservation Organization leads international efforts to control and better manage foreign fisheries to reduce their impacts on Atlantic salmon born in the United States. Not all causes of low ocean survival are well-known. Threats like climate and ocean changes, plus shifts in predator and prey abundance and distribution, appear to affect salmon survival at sea.
Species Recovery
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Atlantic salmon coming out of the top of the Milford fish lift on the Penobscot River.
To work toward recovery of these fish, NOAA Fisheries and the U.S. Fish and Wildlife Service worked with scientists, tribes, and other partners to develop a recovery plan, which was finalized in February 2019. The recovery plan builds upon scientific studies and other observations and information sources to identify gaps in our knowledge and the research needed to fill those gaps. The recovery plan also identifies specific criteria that will signal the recovery of the species.
Primary threats with the potential to limit recovery of the Gulf of Maine DPS of Atlantic salmon include:
Dams and road stream crossings
Climate change
Low marine survival
Loss of genetic diversity
Additionally, the recovery plan identifies numerous secondary threats that, when combined, significantly affect the species chance of survival and recovery. They include:
Reconnect the Gulf of Maine with headwater streams.
Improve habitat productivity to increase the number of salmon smolts entering the ocean.
Increase understanding of and ability to improve marine survival.
In the first five years of Species in the Spotlight initiative (2016-2020), NOAA Fisheries and our partners took important steps toward stabilizing this species and preventing its further decline. Our accomplishments included activities in several areas:
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Releasing a tagged salmon.
Fish Passage
Worked with dam owners to make dams safer for migrating salmon.
Five new fishways planned at hydro dams since 2015.
Habitat Connections
70 aquatic connectivity projects completed in 2018–2019.
Improved access to approximately 250 miles of streams and rivers.
Improvements at road crossing provide for more resilient infrastructure during flooding
Reduce Mortality at Sea
Negotiated 15 metric ton catch reduction at West Greenland for 2018–2020, as well as an improved licensing and catch monitoring program.
Continued work with the North Atlantic Salmon Conservation Organization.
Satellite Tagging to Study Migrations
Satellite tag project to better understand ocean habitat use and migratory patterns.
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2023 Partner in the Spotlight Award
In her capacity as Senior Biologist with the Maine Department of Marine Resources, Joan Trial supervised the assessment, research, and management activities surrounding endangered populations of Atlantic salmon in Maine. Even after departing her role in state government in 2013, she continued to make important contributions by co-authoring several peer-reviewed publications, serving on graduate committees, and working with Project SHARE to lead the assessment work related to habitat rehabilitation in the Narraguagus River. Joan passed away on March 5, 2023, after a short battle with cancer. Her intellect, enthusiasm, and gusto will not be replaced, but will be remembered fondly by many throughout northern New England and beyond.
Maranda Nemeth was named a Partner in the Spotlight in 2021 for her work with the Midcoast Conservancy to remove the Coopers Mills Dam and to partially remove the Head Tide Dam on the Sheepscot River. Combined, the two projects restored access to more than 60 miles of Atlantic salmon spawning and rearing habitat in the Sheepscot River in the Merrymeeting Bay recovery unit. The restoration of the Sheepscot River is a top priority, as it hosts one of the remaining eight river-specific stocks in the Gulf of Maine DPS.
John Banks served as the director of the Penobscot Indian Nation's Department of Natural Resources from 1980-2021. John developed and administered a comprehensive natural resources management program for the Tribe. His program advanced an integrated management approach that recognizes the interconnectedness of all things in the natural world. He has served on numerous boards, commissions, and delegations. These include the U.S. delegation to the North Atlantic Salmon Conservation Organization and the board of directors for the Penobscot River Restoration Trust.
Andy Goode, Vice President of U.S. Programs for the Atlantic Salmon Federation, has been a leader in negotiating dam removals throughout the state of Maine. He was instrumental in negotiating and implementing the Penobscot River Restoration Project. The project removed two mainstem dams on one of the last remaining Atlantic salmon rivers in the United States. In addition, he successfully negotiated the removal of Coopers Mills Dam on the Sheepscot River.
Commercial fishing for Atlantic salmon in the United States is prohibited, making all Atlantic salmon in the U.S. market farmed salmon.
Aquaculture
Atlantic salmon commercially reared in marine net pens on salmon farms are the same genus and species as wild Atlantic salmon (Salmo salar). All Atlantic salmon sold in U.S. seafood markets are farm-raised salmon. The U.S. production of farmed Atlantic salmon is a small segment of the worldwide market, and most of the Atlantic salmon sold in the United States is imported from other countries. Atlantic salmon from U.S. salmon farms is a smart seafood choice because it is sustainably managed and responsibly harvested under U.S. regulations.
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 fish feed to edible protein. Alternative feeds have been developed to reduce the amount of fish meal and fish oil from forage fish.
Farming Methods
Farmed U.S. Atlantic salmon are raised from eggs in on-land hatcheries until they are large enough to transfer to net pens in coastal waters (up to one year).
Human Health
U.S. farmed Atlantic salmon is a healthy option rich in omega-3 fatty acids and vitamin B12.
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 and Wildlife Service, U.S. Department of Agriculture, the Environmental Protection Agency, the Food and Drug Administration, the Bureau of Ocean Energy Management, and the U.S. Coast Guard.
View into Superior Fresh's land-based salmon tank system. Credit: Superior Fresh
U.S. salmon farming begins in on-land hatcheries, where eggs are fertilized and incubated in freshwater tanks. After about a year, the salmon fry go through a complex transformation called smoltification that prepares them for an adult life in saltwater. The fish are then loaded into large, aerated water tanks and transported to marine net pens in coastal waters.
In the net pens, farmed salmon are fed specially formulated feeds and regularly monitored for health and growth until they are large enough to be harvested (approximately two years). Following harvest, the fish are cleaned, placed on ice, and transported to a processing facility where they are packaged for distribution to U.S. markets.
Feeds
Compared to other meats that humans consume for protein, farmed salmon are incredibly efficient at converting fish feed to edible protein. Farmed U.S. salmon eat feeds that are designed to replicate their diets in the wild and made with natural ingredients. Because salmon are carnivorous, their feed typically includes fish meal and fish oil, as well as vitamins, and minerals. Their diet also influences the color of their meat—U.S. farmed salmon are not fed or injected with artificial dyes.
As commercial aquaculture expands to meet the needs of a growing human population, new alternative plant-based feed ingredients are being used to reduce the amount of fish meal and fish oil from forage fish used in salmon feed.
Fish farming can affect water quality and the seafloor health if there is more uneaten food and fish waste than the ecosystem can handle. Potential environmental impacts are largely avoided with proper farm siting, husbandry, management, and modern technologies. Environmental data collected at potential farm sites is used to build mathematical models that help estimate the impacts of the farms. These models allow regulators to understand the risks and benefits of potential fish farms and 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 in areas with strong tidal currents, any additional nutrients from farming are generally not detectable in the water column.
Seafloor Impacts
U.S. salmon farmers use several strategies to limit the impacts of farming on the seafloor:
Choosing locations with strong tidal currents that help disperse and dilute nutrients from farm waste
Using advanced technologies to optimize feed amounts and distribution, minimizing waste
Leaving net pens empty for a period of time between harvests, a practice known as “fallowing.” Fallowing can also help prevent the spread of disease and parasites, including sea lice, by breaking the lifecycle of pathogens that may have inhabited the previous harvest.
Escapes
On rare occasions, farmed salmon escape from marine net pens. If this happens, the fish can negatively impact wild salmon populations. Farmed salmon can increase competition for food and space, disrupt wild salmon spawning behavior, and introduce genetic traits that make the population less fit to survive in the wild.
To reduce the likelihood of escapes, federal and state permits require annual audits of containment management systems at all marine sites. Any escapes of farmed fish are reported to state and federal representatives for awareness and potential identification and removal.
Aquaculture farms can provide a wide range of benefits, from creating habitat for fish and crustaceans to helping improve water quality around farm sites. These benefits are referred to as ecosystem services.
Salmon farms can provide ecosystem services when managed sustainably. For example, the net pens and artificial structures built for farming can also provide refuge for smaller invertebrates and may increase biological productivity directly underneath and around the cages.
Farmed and wild fish, like all animals, are susceptible to bacterial, viral, and parasitic infections. The effects of diseases can vary depending on the environment and condition of the host. Some infections may be overcome by the individual’s immune system. Other diseased fish may express symptoms that lead to compromised health or even death. These effects likely go unnoticed in the wild because unhealthy fish quickly become prey.
Some pathogens that affect salmon are a result of human intervention and fish farming practices. For example, stocking fish from hatcheries into the wild to support recreational fisheries or help recover wild populations can result in the introduction of pathogens.
Disease Treatment and Prevention
Fish farmers keep their fish healthy and disease-free through:
Rigorous fish health and monitoring programs
Vaccinations for specific pathogens
Maintaining healthy farm conditions with a low stress environment through practices such as limiting the density of fish in each pen, and
High-quality, nutritious, food and in some cases probiotics
Most states have comprehensive aquatic animal health regulations, such as requiring routine monthly health exams and prescribing any needed medication by veterinarians.
Some pathogens can be very difficult to manage with and may require complete removal of the infected fish from the farm. These are included in a list of pathogens of special concern and most states have restrictions on interstate transfers of any fish that has been diagnosed.
Managing Parasites
Parasites such as sea lice are controlled on fish farms through a number of methods:
Healing or curative agents such as Hydrogen Peroxide
Mechanical means through specially designed delousing vessels that spray warm water over the fish to remove the lice
Other species, like cleaner wrasses, that eat parasites off of other fish
Relocating or re-stocking farm sites (fallowing) between production cycles
These methods are highly effective at removing most parasites on the fish and eliminating them from the water.
Antibiotic Use
U.S. salmon farmers do not give fish antibiotics to prevent diseases. In the United States, vaccines have been effective in reducing, and in some cases eliminating, the need for antibiotics. Antibiotics are only given under the direction of an on-site veterinarian to treat bacterial infections on a case-by-case basis. In some cases, special permits are required from the U.S. Food & Drug Administration.
Human Health
Contaminants
Both wild and farmed salmon contain low levels of polychlorinated biphenyls (PCBs). The chemicals are passed up the food chain when salmon eat anchovies, herring, capelin, and other fatty fish. Farmed salmon have higher levels of PCBs than the wild population because they are fed a diet rich in fish meal and fish oil. However, the levels in farmed salmon are still significantly below the FDA’s “safe limit.” There are also many efforts underway to develop alternative feeds that don’t rely as heavily on fish meal and fish oil harvested from forage fish.
Aquaculture feeds are also regulated and monitored by the FDA to ensure they do not contain heavy metals, methyl mercury, or other contaminants that could harm fish and human health.
Farmed salmon are not fed or injected with artificial dyes. The rich color of salmon meat is the natural result of their diet, which includes a lot of naturally occurring beta-carotenes.
Health Benefits
As with wild salmon, farmed Atlantic salmon is low in sodium and contains high levels of omega-3 fatty acids and vitamin B12. The specific diet used by salmon farmers will affect the quality, composition, and nutrient levels of the raw meat.
The Gulf of Maine distinct population segment (DPS) of Atlantic salmon is listed as endangered under the Endangered Species Act and is in danger of extinction. In the United States, NOAA Fisheries works to protect all Atlantic salmon.
ESA Conservation & Management
Management Overview
The Gulf of Maine distinct population segment (DPS) of Atlantic salmon is listed as endangered under the Endangered Species Act (ESA) and is in danger of extinction.
In the United States, NOAA Fisheries works to protect all Atlantic salmon. We have specific recovery actions and management strategies for the Gulf of Maine DPS because it is endangered. Recovery of these salmon will be achieved when conditions have been attained that allow self-sustaining populations to persist under minimal ongoing management and investment of resources.
Status
Worldwide, Atlantic salmon populations among individual rivers can range considerably. Atlantic salmon returns to rivers in Northern Europe can exceed nearly a quarter million in some years. However, some populations are small, numbering in the low hundreds or even single individuals. In the United States, wild Atlantic salmon are only found in a few rivers in Maine.
Threats
The most significant threats to the survival of Atlantic salmon include impediments like dams and culverts that block their access to quality habitat, low freshwater productivity, fisheries off the shores of Greenland, and changing conditions at sea. Salmon also face other threats, such as poor water quality, degraded freshwater habitats from land use practices, fish diseases, predation from introduced and invasive species, and interbreeding with escaped fish raised on farms for commercial aquaculture. All of these factors are compounded by climate change—Atlantic salmon are the most vulnerable finfish in the Northeastern United States to this overriding stressor.
Recovery Planning and Implementation
Recovery Action
Under the ESA, NOAA Fisheries must develop and implement recovery plans for the conservation of listed species. The ultimate goal of the plan is to recover the species, with an interim goal of down-listing its status from endangered to threatened.
The recovery plan for the Gulf of Main DPS of Atlantic salmon recommends the following major actions:
Improve connections between ocean and freshwater habitats important for salmon recovery.
Maintain genetic diversity of Atlantic salmon populations over time.
Increase the number of reproducing adults through the conservation hatchery program.
Increase the number of reproducing adults through the freshwater production of smolts.
Increase Atlantic salmon survival by improving our understanding of marine ecosystems and the factors that affect salmon in the ocean.
Consult with all involved tribes on a government-to-government basis.
Collaborate with partners and involve interested parties in recovery efforts.
The Collaborative Management Strategy is a governance process that describes the working relationships between the two Federal agencies (U.S. Fish and Wildlife Service and NOAA Fisheries), Maine’s Department of Marine Resources, the Penobscot Indian Nation, and other partners.
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The Ripple Effects of Atlantic Salmon Conservation
Consulting on Actions That Affect Salmon and Their Critical Habitat
Any federal agencies conducting or permitting projects that may affect Atlantic salmon or adversely modify their critical habitat must consult with us, as required by Section 7 of the ESA.
In 2009, we designated specific freshwater and estuarine areas in Maine as critical habitat for Atlantic salmon. We designated these areas because they contain features that are essential for Atlantic salmon survival. These areas provide important spawning, feeding, and migratory habitats for Atlantic salmon.
Julie Crocker, Endangered Species Branch Chief , (978) 282-8480, julie.crocker@noaa.gov
Dan Tierney, Atlantic Salmon Recovery Coordinator, (207) 866-3755, dan.tierney@noaa.gov
Rory Saunders, Atlantic Salmon Recovery Coordinator for the Downeast SHRU, (207) 866-4049, rory.saunders@noaa.gov
Matt Buhyoff, Atlantic Salmon Recovery Coordinator for the Merrymeeting Bay SHRU, (207) 866-4238, matt.buhyoff@noaa.gov
Dan Kircheis, Atlantic Salmon Recovery Coordinator for the Penobscot SHRU, (207) 866-7320, dan.kircheis@noaa.gov
Conservation Efforts
Habitat Restoration and Fish Passage
Atlantic salmon need a wide range of well-connected habitat types. In freshwater, dams and other barriers to migration block or impede salmon from accessing important spawning and nursery habitats. Approximately 90 percent of Atlantic salmon’s historical freshwater habitat remains impeded by dams.
NOAA Fisheries is working with dam owners to find solutions that will allow salmon to recover. We have provided significant resources for the oversight, funding, and monitoring of dam removals throughout the Gulf of Maine DPS.
Furthermore, NOAA Fisheries staff continue to work with hydropower owners to plan for effective downstream and upstream fish passage at most major hydropower dams within the designated critical habitat area for Atlantic salmon. The goal is to restore access to climate resilient watersheds that contain habitat suitable for Atlantic salmon spawning and rearing.
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The Ripple Effects of Atlantic Salmon Conservation. Salmon restoration benefits the ecosystem as a whole by reconnecting rivers to the ocean, improving freshwater habitat, and building resilient ecosystems.
Captive Breeding and Stocking Programs
Hatchery programs have supported Atlantic salmon populations throughout New England and have prevented extinction in many of Maine's rivers where local populations were at critically low numbers that are needed for the species to reproduce and create the next generation. They also provided opportunities for an economically important recreational fishery to operate through the early 1990s.
The U.S. Fish and Wildlife Service currently has two hatcheries in Maine that conduct a conservation hatchery program. This is a river-specific stocking program, meaning that the program releases the offspring of individuals collected from a specific river back into that river. The program aims to increase the size of wild and captive river-specific populations and to have a reserve of captive salmon for stocking into vacant habitat or rivers in which wild salmon are not returning to their native habitats.
The hatchery program will continue to support conservation activities, including artificial breeding, stocking, and broodstock collection from several rivers throughout Maine. As part of ongoing recovery efforts, the facilities will also maintain captive brood lines for the Gulf of Maine population for as long as needed.
Producing Young Salmon
Producing more naturally reared smolts is the primary objective for the Atlantic salmon program during times when few salmon survive in the ocean. NOAA Fisheries aims to get more smolts, or young salmon, successfully out of rivers and into the ocean.
In the short term, smolt production could increase by changing hatchery and stocking practices. For example, researchers could target habitats that do not currently have any salmon. This can help offset the population decrease caused by ongoing threats, but has limited ability to fully recover imperiled salmon populations. Increasing accessibility to critical habitats is one of the many goals of the program and is part of the multifaceted Atlantic salmon recovery program currently in place.
International Cooperation
International fisheries, such as those in Greenland, can catch salmon that originate from the United States. The North Atlantic Salmon Conservation Organization sets catch limits and licensing requirements for fisheries in Greenland. Canada, Denmark, the European Union, Norway, the Russian Federation, and the United States are members of NASCO and work together to manage Atlantic salmon throughout their range. NASCO also works to reduce the Greenland fishery's impact on U.S.-origin fish.
You can contribute significantly to Atlantic salmon recovery by implementing best management and land stewardship practices:
Maintain forested areas next to rivers and streams to provide shade, nutrients, and cover to support Atlantic salmon and other fish.
Maintain native plants along waterways which support healthy forests and keep dirt and other materials out of streams. Dirt fills in spaces between rocks that Atlantic salmon use to lay eggs and hide from predators.
Avoid removing wood from Maine waterways and their banks. Wood provides important habitat for Atlantic salmon and other fish to feed and find shelter.
Participate in programs to conserve land and water resources for Atlantic salmon habitats.
Learn About Bycatch
One of the main threats to marine animals is entanglement in fishing gear, especially gillnets. Fishermen sometimes catch and discard animals they do not want, cannot sell, or are not allowed to keep. This is collectively known as bycatch.
Know the Law Before You Fish
It is illegal to fish for, catch, or keep fish from the Gulf of Maine Atlantic salmon DPS.
Report a Violation
Call the NOAA Fisheries Enforcement Hotline at (800) 853-1964 to report a federal marine resource violation. This hotline is available 24 hours a day, 7 days a week for anyone in the United States. You may also contact your closest NOAA Office of Law Enforcement field office during regular business hours.
In 2017, NOAA Fisheries announced the initiation of a 5-year review for the Gulf of Maine Distinct Population Segment (DPS) of Atlantic Salmon (Salmo salar).
NOAA Fisheries is required by the Endangered Species Act (ESA) to conduct 5-year…
We, NOAA Fisheries, issue a final rule designating critical habitat for the Atlantic salmon (Salmo salar) Gulf of Maine Distinct Population Segment (GOM DPS). We previously determined that naturally spawned and several hatchery populations of Atlantic…
We (NOAA Fisheries and U.S. Fish and Wildlife Service, collectively referred to as the Services) have determined that naturally spawned and conservation hatchery populations of anadromous Atlantic salmon (Salmo salar) whose freshwater range occurs in…
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.
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.
Co-Evolved Fish
The health of Atlantic salmon is directly affected by the health of their ecosystem, which includes the other species living in that ecosystem. Atlantic salmon co-evolved and historically shared the rivers of Maine with many other fish that provide alternative food sources for salmon predators and the salmon themselves. Co-evolved fish also influenced the amount of nutrients available and the habitat quality. Our scientists study how changes in co-evolved fish populations affect the recovery of Atlantic salmon.
Smolt Dam Passage
Salmon are famous for fighting their way upstream to spawn, but their trip downstream as young smolts is no less important. Our scientists study how passage through or around dams affects smolts. Scientists surgically implanted tags into 941 smolts in the Penobscot River between 2005 and 2013. Each tag emits a sound unique to the fish carrying it. Receivers then pick up the sound as the fish travels down the river to track its progress.
This research reveals that even if smolts make it past the dams, they might suffer injuries that make them more likely to die days or weeks later in the estuary, where the river meets the sea. And for each dam a smolt passes, researchers found that the smolt’s chance of dying in the estuary increases by 6 to 7 percent.
Researching Atlantic Salmon in Maine
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Salmon migrating upstream through a fish passage. Credit: NOAA Northeast Fisheries Science Center
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.
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.
The National Ocean Service’s CAPP Program assesses aquaculture environmental interactions and develops spatial planning and eco forecasting 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.
Genetic Diversity & Genomics
NOAA Fisheries is monitoring the genetic diversity of Atlantic salmon to ensure that salmon born in hatcheries can have a good chance at surviving in the wild. We also want to make sure that wild salmon are genetically diverse and this diversity is maintained in the captive broodstock lines held at the hatchery. This information will help us monitor the overall genetic diversity within the Gulf of Maine distinct population segment (DPS) and inform best practices for hatchery management and supplementation efforts supporting recovery.
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.
Disease Surveys
Our scientists study the parasites, bacteria, and viruses that can affect Atlantic salmon health. Populations that are already threatened are especially vulnerable to disease outbreaks, so it is important to understand how specific pathogens could affect the Gulf of Maine DPS. Scientists have sampled several fish species for pathogens, including cod, eel, halibut, mackerel, trout, smelt, and flounder. Since 2000, scientists have sampled over 5,000 fish representing 23 species. These 23 species can all interact with Atlantic salmon in shared habitats. Collaborative efforts will help improve our understanding of diseases and our ability to prevent and manage disease outbreaks.
Stock Assessments
Determining the number of salmon in the Gulf of Maine DPS—and whether the population is increasing or decreasing over time—helps resource managers assess the successes and failures of enacted conservation measures and helps to guide future recovery actions. Our scientists collect information and present these data in annual stock assessment reports.
This database contains historic adult return, adult stocking, juvenile stocking, egg production, and aquaculture data for Atlantic salmon in New England Rivers.
