The term salmon originally referred to the Atlantic salmon ( Salmo salar ), but today it includes similar fishes in the family Salmonidae, especially the Pacific salmon of the genus Oncorhynchus . Six species of Pacific salmon exist: sockeye, coho, chum, king, pink, and cherry salmon. The Atlantic salmon is native to rivers on both sides of the North Atlantic. Salmon are known for their life cycle. They hatch in streams, migrate to the ocean, and then return to their birthplace to spawn and die. They use their sense of smell and ability to sense Earth’s magnetic field to navigate back to their home stream. Salmon are a popular food and sport fish.

Where do salmon live?

Salmon can be found in both freshwater and marine environments. They live in the sea, but migrate to fresh water to breed. Pacific salmon reside in the northern Bering Sea to Japan, and the Columbia River of the American Northwest, while the Atlantic salmon is native to rivers on both sides of the North Atlantic. They spawn in cold, clear lakes or upper streams, laying eggs in gravel beds. After hatching, young salmon consume the yolk before seeking food. Salmon are known for their homing instinct, returning to their birth stream to reproduce. They use their sense of smell to locate their natal stream from the ocean. Pacific salmon live most of their lives in the ocean, but as adults they return to the stream where they hatched in order to spawn.

Salmon are mostly predators that eat other fish and large invertebrates. However, the process of evolution modifies and adapts species to exploit a variety of food resources. As young fry, salmon consume the yolk in their attached sac before seeking food. As they mature, their diet expands. In the ocean, salmon eat zooplankton and other small organisms. Some farmed salmon are fed chicken and grain products, while others eat products derived from wild-caught fish. Adult salmon do not eat when they run upriver to spawn, though they may strike at fishing lures.

How do salmon reproduce?

Salmon exhibit an anadromous life cycle, migrating from the sea to fresh water to breed. They spawn in cold, clear lakes or upper streams, laying eggs in gravel beds. Pacific salmon put all their energy into returning to their birthplace to spawn, ceasing to eat and relying on stored energy. This journey can be very strenuous, with some species swimming over 2,000 miles to reach their spawning grounds. After changes occur in color and external features, adult salmon return to fresh water to spawn. Females produce large eggs, 4 to 8 mm in diameter, with a large yolk to nourish the developing embryo. After spawning, Pacific salmon die, ensuring the next generation's survival. Some Atlantic salmon die after spawning, but others return to the sea.

Why do salmon swim upstream?

Salmon swim upstream from the ocean to the freshwater streams where they were born to spawn and die. This journey can be very long and strenuous, with some species swimming over 2,000 miles. The reasons salmon swim upstream: * Reproduction Salmon return to their birthplace to lay eggs. * Energy Salmon have bodies rich in oils that give them the energy needed to navigate the journey upriver. * Anadromous adaptation Salmon are anadromous fish, meaning they live in the sea and migrate to fresh water to breed. * Homing instinct Salmon are able to return to their hatching streams due to their experiential imprinting and strong sense of smell.

How are salmon important to people and the environment?

Salmon are vital to both people and the environment. As a food source, they have been a primary sustenance for cultures of the Plateau region, who relied on various methods to catch and preserve them. Today, the economic value of trout and salmon is well-recognized, with governments investing in maintaining their production for both sport and commerce. Ecologically, salmon play a crucial role in their native habitats. After spending their adult lives in the ocean, they return to their birthplace in freshwater streams to spawn. This journey enriches the streams with marine-derived nutrients, as Pacific salmon die after spawning, ensuring the next generation has the best chance of survival.

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Images & Videos

Several Pacific salmon leap up a rushing waterfall in Brooks River, Katmai National Park, Alaska, as they swim upstream to spawn.

Kamchatka brown bears and the annual salmon run

Slices of rye bread topped with butter and bright orange salmon caviar arranged closely together.

A person uses chopsticks to pick up a slice of salmon sashimi from a bowl filled with ice, with side dishes and condiments on the table in Nakhon Pathom, Thailand.

Lateral anatomical diagram of a salmon showing trunk muscles, with labeled sections for epaxial and hypaxial musculature, myomeres, myosepta, and the horizontal septum.

Diagram showing four types of fish scales: ctenoid scales from a bass, cycloid scales from a salmon, ganoid scales from a gar, and placoid scales from a shark, each illustrated with a close-up and the corresponding fish silhouette.

At a Glance

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Quick Facts

Related Topics:: fish; teleost; Why do salmon die after spawning?; Atlantic salmon; Pacific salmon

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Top Questions

What is a salmon?
The term salmon originally referred to the Atlantic salmon (Salmo salar), but today it includes similar fishes in the family Salmonidae, especially the Pacific salmon of the genus Oncorhynchus.

Six species of Pacific salmon exist: sockeye, coho, chum, king, pink, and cherry salmon. The Atlantic salmon is native to rivers on both sides of the North Atlantic.

Salmon are known for their life cycle. They hatch in streams, migrate to the ocean, and then return to their birthplace to spawn and die. They use their sense of smell and ability to sense Earth’s magnetic field to navigate back to their home stream. Salmon are a popular food and sport fish.
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Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Where do salmon live?
Salmon can be found in both freshwater and marine environments. They live in the sea, but migrate to fresh water to breed. Pacific salmon reside in the northern Bering Sea to Japan, and the Columbia River of the American Northwest, while the Atlantic salmon is native to rivers on both sides of the North Atlantic. They spawn in cold, clear lakes or upper streams, laying eggs in gravel beds. After hatching, young salmon consume the yolk before seeking food.

Salmon are known for their homing instinct, returning to their birth stream to reproduce. They use their sense of smell to locate their natal stream from the ocean. Pacific salmon live most of their lives in the ocean, but as adults they return to the stream where they hatched in order to spawn.
4 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
What do salmon eat?
Salmon are mostly predators that eat other fish and large invertebrates. However, the process of evolution modifies and adapts species to exploit a variety of food resources.

As young fry, salmon consume the yolk in their attached sac before seeking food. As they mature, their diet expands. In the ocean, salmon eat zooplankton and other small organisms. Some farmed salmon are fed chicken and grain products, while others eat products derived from wild-caught fish. Adult salmon do not eat when they run upriver to spawn, though they may strike at fishing lures.
5 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
How do salmon reproduce?
Salmon exhibit an anadromous life cycle, migrating from the sea to fresh water to breed. They spawn in cold, clear lakes or upper streams, laying eggs in gravel beds. Pacific salmon put all their energy into returning to their birthplace to spawn, ceasing to eat and relying on stored energy. This journey can be very strenuous, with some species swimming over 2,000 miles to reach their spawning grounds.

After changes occur in color and external features, adult salmon return to fresh water to spawn. Females produce large eggs, 4 to 8 mm in diameter, with a large yolk to nourish the developing embryo. After spawning, Pacific salmon die, ensuring the next generation's survival. Some Atlantic salmon die after spawning, but others return to the sea.
5 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Why do salmon swim upstream?
Salmon swim upstream from the ocean to the freshwater streams where they were born to spawn and die. This journey can be very long and strenuous, with some species swimming over 2,000 miles.

The reasons salmon swim upstream:
* Reproduction Salmon return to their birthplace to lay eggs.
* Energy Salmon have bodies rich in oils that give them the energy needed to navigate the journey upriver.
* Anadromous adaptation Salmon are anadromous fish, meaning they live in the sea and migrate to fresh water to breed.
* Homing instinct Salmon are able to return to their hatching streams due to their experiential imprinting and strong sense of smell.
5 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
How are salmon important to people and the environment?
Salmon are vital to both people and the environment. As a food source, they have been a primary sustenance for cultures of the Plateau region, who relied on various methods to catch and preserve them. Today, the economic value of trout and salmon is well-recognized, with governments investing in maintaining their production for both sport and commerce.

Ecologically, salmon play a crucial role in their native habitats. After spending their adult lives in the ocean, they return to their birthplace in freshwater streams to spawn. This journey enriches the streams with marine-derived nutrients, as Pacific salmon die after spawning, ensuring the next generation has the best chance of survival.
6 Britannica Sources
Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

salmon, originally, the large fish now usually called the Atlantic salmon (Salmo salar), though more recently the name has been applied to similar fishes of the same family (Salmonidae), especially the Pacific salmon, which constitute the genus Oncorhynchus.

The six species of Pacific salmon (Oncorhynchus) are the following: the sockeye or red salmon (O. nerka), which ranges from the northern Bering Sea to Japan and the Columbia River of the American Northwest; the coho or silver salmon (O. kisutch), ranging from the Bering Sea to Japan and the Salinas River of Monterey Bay; the chum or dog salmon (O. keta), ranging from the Mackenzie and Lena rivers in the southern Arctic southward to Japan and the Rogue River; the king, spring, or chinook salmon (O. tshawytscha), from the Yukon River to China and the Sacramento River; the pink or humpback salmon (O. gorbuscha), from the Arctic to Japan and the Klamath River; and the cherry salmon (O. masu), which is found off Japan. The Atlantic salmon is native to the rivers on both sides of the North Atlantic.

The adult Atlantic salmon averages about 10 pounds (4.5 kg) in weight, while the king salmon averages about 23 pounds (10 kg), though individuals of 50–80 pounds (22–36 kg) are not uncommon. Chum salmon average about 10–12 pounds (4.5–5.5 kg); coho salmon weigh about 7–10 pounds (3–4.5 kg); sockeye, about 4–7 pounds (2–3 kg); and pink salmon, 3–6 pounds (1.3–2.7 kg).

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Pacific salmon live most of their life in the ocean, but as adults they return to the stream where they hatched in order to spawn. They use their olfactory senses (their sense of smell) to find their spawning grounds in their home river, and at least one species, the sockeye salmon (Oncorhynchus nerka), can also sense differences in Earth’s magnetic field to navigate back to its home stream from the open ocean. The female digs a pit in the stream gravel into which she and a male spawn simultaneously, and she then covers up the eggs with gravel. Adult Pacific salmon die soon after spawning, but many Atlantic salmon return to the sea and after one or two years in open waters may spawn again, some up to three or four times. Most salmon spawning takes place in late summer or fall, and the eggs usually hatch in late winter. Incubation rates depend on temperature, taking from 60 up to 200 days. After hatching, the salmon fry consume the yolk in the attached sac before wriggling up through the gravel to seek food. Young pink salmon descend almost immediately to the sea, while chum salmon leave in a few weeks. Coho salmon remain an entire year in the streams, while young king and Atlantic salmon may remain feeding in streams for one to three or more years. Young sockeye salmon dwell for one to five years in lakes before migrating seaward.

Salmon are silvery-sided fishes while in the ocean, but during the breeding season a change in coloration occurs that varies from one species to another. The males generally develop hooked jaws. The changes are most striking in male Pacific salmon. Adults run upriver in spring or fall and take no food, although they will strike at fishing lures. The spawning grounds may be close to the sea, but the king and chum salmon swim more than 2,000 miles (3,200 km) up the Yukon River to spawn in its headwaters. The migrating salmon, impelled by instinct, fight rapids and leap high falls until they reach their spawning grounds. Even landlocked salmon, which mature in deep lakes, ascend tributary streams to spawn.

Atlantic salmon, though fished commercially in certain areas, are valued chiefly as sport fish. They are farmed in fish pens in many parts of the world. The king and coho salmon are prized sport fish in the larger rivers of the Pacific coast. The commercial fishery of Pacific salmon nets millions of pounds annually, of which nearly half is pink salmon, one-third is chum salmon, and most of the remainder is sockeye.

This article was most recently revised and updated by Amy Tikkanen.

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