Salmon belong to the family Salmonidae, and their closest relatives include trout, char, grayling, and whitefish. Rainbow trout (Oncorhynchus mykiss) is especially close, sharing both genetics and ecological overlap.
20–60 in (50–150 cm)
Length
4–100 lbs (1.8–45 kg)
Weight
About
The Salmon is one of the world’s most celebrated fish, known for its epic migrations, cultural significance, and ecological importance. Belonging to the family Salmonidae, which also includes trout and char, salmon are primarily found in the North Atlantic (Salmo salar) and the Pacific (Oncorhynchus species). Their life cycle, in which they hatch in freshwater rivers, migrate to the ocean, and then return to their natal streams to spawn, is one of nature’s most extraordinary journeys.
Salmon exhibit incredible diversity, with several species recognized: the Atlantic salmon in the Atlantic, and Pacific salmon such as Chinook, Sockeye, Coho, Chum, and Pink. Sizes range from the small pink salmon, typically 3–5 pounds (1.5–2.5 kg), to Chinook salmon, which can exceed 100 pounds (45 kg). They are distinguished by their streamlined, silvery bodies that often shift to vibrant reds, greens, or purples during spawning.
Their diet varies with age and habitat. Juveniles feed on aquatic insects and plankton, while adults in the ocean consume fish, squid, and crustaceans, which contribute to their rich, fatty flesh. This diet not only fuels their migrations but also makes salmon a nutritional powerhouse for humans, providing omega-3 fatty acids and high-quality protein.
Ecologically, salmon are a keystone species. Their spawning migrations bring marine nutrients into freshwater ecosystems, feeding bears, eagles, wolves, and even forests through decaying carcasses. Culturally, they hold deep significance for Indigenous peoples of the Pacific Northwest and have long been central to human diets and economies worldwide.
Conservation challenges include overfishing, habitat loss, climate change, and obstacles like dams that block spawning routes. Efforts to restore salmon runs through hatcheries, dam removal, and habitat protection highlight their importance.
With their resilience, beauty, and vital ecological role, salmon symbolize the interconnectedness of rivers, oceans, wildlife, and human cultures.
Threatened:
Extinct
Critically Endangered
Endangered
Vulnerable
Near Threatened
Least Concern
Physical Characteristics
Salmon are iconic migratory fish, recognized for their streamlined bodies, silver sheen, and dramatic physical transformations during spawning.
Body:
They have a sleek, torpedo-shaped body built for long migrations between freshwater and saltwater. Their skin is covered in small, cycloid scales that reduce drag in fast-flowing currents.
Coloration:
At sea, salmon are typically silver with a bluish or greenish back, helping with camouflage in open water. During spawning, their colors shift dramatically—males often turn reddish, copper, or dark green, with hooked jaws and humped backs developing in some species.
Mouth and Teeth:
They have a large mouth lined with small, sharp teeth used to grasp prey. During spawning, males often develop an exaggerated hooked jaw called a kype for fighting rivals.
Fins:
Salmon possess a single dorsal fin and a small fleshy adipose fin, characteristic of salmonids. Their caudal fin is forked, built for endurance swimming.
Size:
Size varies widely by species. Smaller salmon, like the pink salmon, average 20–25 in (50–64 cm) in length, while Chinook salmon can exceed 60 in (150 cm).
Weight:
Most species weigh between 4–15 lbs (1.8–6.8 kg), but large Chinook can surpass 100 lbs (45 kg), making them the heaviest salmon.
The salmon’s silver ocean form, spawning transformations, and strong swimming body make it one of the most recognizable and remarkable migratory fish in the world.
Reproduction
Salmon are famous for their dramatic reproductive migrations, returning from the ocean to the freshwater streams where they were born.
Mating and Courtship:
When salmon reach maturity, they undergo a spawning migration, traveling hundreds of miles upstream. Males often develop hooked jaws (kypes), vivid coloration, and aggressive behaviors to compete for females.
Spawning Grounds:
Females choose gravel-bottomed stream beds with clean, oxygen-rich water. Using powerful tail movements, they dig shallow nests called redds where eggs will be deposited.
Egg Laying and Fertilization:
Females lay hundreds to several thousand eggs in a redd. Males release milt (sperm) over the eggs for external fertilization. The female then covers the fertilized eggs with gravel for protection.
Eggs and Development:
Eggs develop over several weeks to months depending on water temperature. Embryos hatch as alevins, still attached to yolk sacs, which provide nourishment.
Fry Stage:
Once yolk sacs are absorbed, young salmon, now called fry, emerge from the gravel to feed on insects and plankton.
Smolt and Migration:
As juveniles grow, they undergo a physiological change called smoltification, adapting their bodies to saltwater before migrating to the ocean.
Life Cycle Completion:
After spending 1–5 years at sea, salmon return to their natal streams to spawn and, in most species, die shortly after reproduction—a process known as semelparity.
The salmon’s epic migration and life cycle make its reproduction one of the most extraordinary events in the animal kingdom.
Lifespan
Salmon have varied lifespans depending on the species, but all follow a cycle of hatching in freshwater, maturing in the ocean, and returning to spawn.
Lifespan in the Wild:
Most salmon live 2–7 years. Pink salmon are the shortest-lived, completing their life cycle in about 2 years, while Chinook salmon are the longest-lived, sometimes reaching 7 years.
Species Variation:
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Pink salmon: ~2 years
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Sockeye salmon: 4–5 years
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Coho salmon: 3–4 years
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Chum salmon: 3–5 years
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Chinook salmon: 4–7 years
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Atlantic salmon (not a Pacific species): 4–6 years, with some surviving longer.
Post-Spawning Survival:
Pacific salmon species are semelparous, meaning they die after spawning. In contrast, Atlantic salmon are iteroparous, meaning some survive spawning and may return to the ocean to spawn again.
Lifespan in Captivity:
Salmon in hatcheries or aquaculture generally live 2–5 years before harvest, but under controlled conditions they can reach their natural maximum lifespan.
The salmon’s lifespan reflects both its intense migratory life cycle and its species-specific adaptations, ranging from the brief two-year life of pink salmon to the seven-year span of Chinook.
Eating Habits
Salmon are opportunistic predators whose diet changes significantly between freshwater and marine stages of life.
Diet (Freshwater Juveniles):
Young salmon, called fry and parr, feed mainly on aquatic insects, insect larvae, plankton, and small crustaceans. This high-protein diet fuels rapid early growth.
Diet (Marine Adults):
In the ocean, salmon feed heavily on fish such as herring, capelin, and anchovies, as well as squid, shrimp, and krill. Their marine diet contributes to their rich, fatty flesh.
Feeding Behavior:
They are visual hunters, relying on sharp eyesight to locate prey. Salmon are active feeders, often hunting near the surface or in midwater zones.
Foraging Strategy:
Salmon migrate great distances at sea, following schools of prey fish and seasonal shifts in food abundance. Their diet adapts to whatever prey is available in their oceanic range.
Spawning Season:
As salmon return to freshwater to spawn, they stop feeding entirely, relying on stored energy reserves to complete their migration and reproduction.
The salmon’s flexible diet, shifting from insects in rivers to fish and squid at sea, underpins their ability to thrive in both freshwater and marine environments.
Uniqueness
Salmon are extraordinary fish, renowned for their epic migrations, ecological importance, and cultural value.
Epic Migration:
They travel hundreds, sometimes thousands, of miles from the ocean back to their natal freshwater streams to spawn, guided by an exceptional sense of smell and geomagnetic navigation.
Life Cycle Variety:
Most Pacific salmon die after spawning (semelparity), while Atlantic salmon may survive and spawn multiple times (iteroparity), a rare distinction among salmonids.
Physical Transformations:
During spawning, salmon undergo dramatic changes—males develop hooked jaws (kypes), vivid red or green coloration, and even humped backs in some species.
Ecological Role:
Their death after spawning provides vital nutrients to freshwater ecosystems, feeding bears, eagles, and forests alike, making salmon a keystone species in many habitats.
Cultural and Economic Significance:
For centuries, salmon have been central to the diet, culture, and spirituality of Indigenous peoples and remain one of the world’s most valuable commercial and sport fish.
The salmon’s combination of epic migrations, transformative life cycle, and ecological importance makes it one of the most unique and iconic fish species on Earth.
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FAQ’s
1. What species is closest to the salmon?
2. How does the salmon compare to other species in the same family?
Compared to trout and char, salmon are generally larger, more migratory, and undergo more dramatic physical changes during spawning. While trout often remain in freshwater, salmon complete long ocean migrations.
3. What national parks provide the best opportunities to see a salmon?
Salmon can be seen in Katmai National Park and Preserve (Alaska), Olympic National Park (Washington), and Glacier Bay National Park (Alaska), where their migrations attract bears, eagles, and visitors alike.
4. In what parts of the world can you find salmon?
They are native to the North Pacific and North Atlantic Oceans, along with connected rivers in North America, Europe, and Asia. Introduced populations also exist in South America, New Zealand, and Australia.
5. How many types of salmon are there?
There are six main species: five Pacific salmon (Chinook, Coho, Sockeye, Chum, and Pink) and one Atlantic salmon (Salmo salar). Numerous subspecies and landlocked forms also exist.
