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Species Profile

Steelhead Salmon

Oncorhynchus mykiss

Sea-run rainbow, built to return
David A Litman/Shutterstock.com

Steelhead Salmon Distribution

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Invasive Species

This map shows coastal regions where Steelhead Salmon are found.

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Steelhead trout swimming

At a Glance

Wild Species
Also Known As Rainbow trout, Sea-run rainbow trout, Sea-run rainbow, Steelie, Sea trout, Pacific rainbow trout
Diet Carnivore
Activity Diurnal+
Lifespan 5 years
Weight 25 lbs
Status Least Concern
Did You Know?

Steelhead and rainbow trout are the same species: Oncorhynchus mykiss-the difference is life history (anadromous vs. resident).

Scientific Classification

Steelhead are the ocean-migrating (anadromous) ecotype of the Rainbow Trout. They hatch in freshwater, migrate to the sea to grow, and return to rivers to spawn; unlike many Pacific salmon, individuals may survive spawning and return again (iteroparity).

Kingdom
Animalia
Phylum
Chordata
Class
Actinopterygii
Order
Salmoniformes
Family
Salmonidae
Genus
Oncorhynchus
Species
mykiss

Distinguishing Features

  • Sea-run form of Rainbow Trout (same species), often more silvery with fewer visible spots while in marine phase
  • Returns from ocean to freshwater to spawn; may spawn more than once
  • Typically more streamlined and larger on average than resident rainbow trout from the same watershed

Did You Know?

Steelhead and rainbow trout are the same species: Oncorhynchus mykiss-the difference is life history (anadromous vs. resident).

Recorded maximum size for O. mykiss: 120 cm total length and 25.0 kg (FishBase species summary data).

Maximum reported age for O. mykiss is 11 years (FishBase).

Steelhead often show "silvering" at sea: a bright, reflective body that helps camouflage in open water (countershading).

Unlike most Pacific salmon (genus Oncorhynchus) that usually die after spawning, steelhead are notable for iteroparity-some individuals can return to the ocean and spawn in more than one year.

Steelhead runs are often described by run timing: "summer-run" (enter rivers sexually immature, hold months) vs. "winter-run" (enter closer to spawning).

Like other salmonids, they navigate with strong homing ability, using olfactory imprinting to relocate natal waters-yet some "straying" occurs, aiding colonization of new habitats.

Unique Adaptations

  • Smoltification (physiological switch for seawater): remodeling of gills and ion-transport systems enables transition from freshwater osmoregulation to saltwater tolerance-a hallmark adaptation shared across anadromous salmonids.
  • Streamlined, high-performance swimming: a fusiform body, powerful caudal peduncle, and high aerobic capacity support long upriver migrations and strong station-holding in currents.
  • Countershading and ocean "silvering": darker back + bright sides reduce visibility to predators/prey in open water; many steelhead lose prominent freshwater spotting while at sea.
  • Cold-water respiration efficiency: as salmonids (family Salmonidae), steelhead have high gill surface area and oxygen uptake suited to cold, oxygen-rich rivers-yet they are sensitive to warm-water stress, shaping their distribution.
  • Life-history plasticity (resident ↔ anadromous): O. mykiss can express different growth/maturation pathways, allowing populations to persist across variable river and ocean conditions.

Interesting Behaviors

  • Anadromous migration pattern: hatch and rear in freshwater; smoltify and migrate to marine/brackish waters for rapid growth; return upstream to spawn in gravel (redd) nests.
  • Iteroparity (repeat spawning): after spawning, some steelhead "kelts" survive, return downstream, recondition in the ocean, and may spawn again in later years.
  • Run-timing strategies: summer-run fish may enter freshwater months before spawning and hold in deep pools/covered habitats; winter-run fish typically migrate upriver nearer to spawning time during higher flows.
  • Redd construction and spawning: females excavate a gravel redd with vigorous tail beats; eggs are deposited and fertilized; the female then covers the nest with gravel to protect embryos from predation and oxygen deprivation.
  • Juvenile habitat use: young O. mykiss often establish feeding territories in riffle/run habitats, balancing drift-feeding opportunities against predation risk.
  • Homing and sensory orientation: like other salmonids, steelhead rely heavily on chemical cues (olfaction) for natal stream recognition; they also use flow, temperature gradients, and geomagnetic/orientation cues during migration.
  • Flexible life history: within the species, some individuals remain resident (rainbow trout form) while others become anadromous-this plasticity can vary among populations and environmental conditions.

Cultural Significance

Steelhead (anadromous Rainbow Trout) are a key sport fish in the Pacific Northwest. They are important to Indigenous river and salmon lifeways, local subsistence and trade, and drive conservation and water-management debates because they need connected cold-water habitat from headwaters to sea.

Myths & Legends

Many Indigenous peoples, including Coast Salish, hold First Salmon rites, welcoming the fish and returning bones to the river so Salmon People will keep offering themselves. Steelhead (anadromous Rainbow Trout, Oncorhynchus mykiss) are often included.

Northwest Coast Salmon People stories say salmon are people who take off a salmon "cloak" to live in underwater villages. They teach that respectful human actions bring salmon and steelhead back each year.

"Salmon Boy" (Tlingit story): A boy who doesn't respect salmon is taken to live with them, learns their ways, then returns to teach his people respect — an origin lesson about salmonids returning to rivers.

Conservation Status

LC Least Concern

Widespread and abundant in the wild.

Population Stable

Protected Under

  • United States: Numerous steelhead Distinct Population Segments (DPS) are listed under the Endangered Species Act (ESA) as Threatened or Endangered (e.g., Southern California steelhead DPS-Endangered; California Central Valley steelhead DPS-Threatened), with critical habitat designated for several DPS.
  • Canada: Some steelhead/rainbow trout designatable units have been assessed at risk by COSEWIC; legal protection under the federal Species at Risk Act (SARA) varies by population and listing decisions.
  • HUBS summary (O. mykiss complex): Global species status is LC, but conservation outcomes are driven by population-level listings ranging from not-at-risk to Endangered. Common threats include barriers and flow alteration, warming waters, sediment/pollution, hatchery genetic impacts, and mixed-stock harvest; notably imperiled units include Southern California and several Columbia-Snake and Central Valley steelhead populations.

Life Cycle

Birth 4000 frys
Lifespan 5 years

Lifespan

In the Wild
2–11 years
In Captivity
2–11 years

Reproduction

Mating System Polygynandry
Social Structure Aggregation Group
Breeding Pattern Transient
Fertilization Substrate Spawning
Birth Type Substrate_spawning

Spawning occurs in river aggregations where females excavate gravel redds and release eggs while one or more males compete and simultaneously release milt (external fertilization). Both sexes may spawn with multiple partners within and across seasons; no pair bond or parental care follows.

Behavior & Ecology

Social School Group: 25
Activity Diurnal, Crepuscular
Diet Carnivore Forage fish (small pelagic fishes) during the marine growth phase; in freshwater rearing habitats, drifting aquatic insects (mayfly and caddisfly larvae, and fly larvae) are core foods.
Seasonal Migratory 1,864 mi

Temperament

Freshwater juveniles and adults commonly territorial over feeding stations; dominance hierarchies form in confined habitats
Boldness/aggression varies with size, density, and food availability; larger fish typically dominate
During spawning migrations, tolerance increases and fish aggregate temporarily in holding pools
Generally wary/avoidant of predators; risk-taking increases under low light (crepuscular periods)

Communication

None documented; salmonids are generally considered non-vocal in natural contexts
Chemical/olfactory cues: natal homing and mate/spawning-site recognition via dissolved odors E.g., pheromonal cues
Visual signals: lateral displays, fin erection, and body postures used in aggression and courtship
Mechanosensory cues: lateral-line detection of neighbor movements supports spacing in shoals/schools
Tactile contact: close-body interactions during courtship and spawning Pair alignment, nudging

Habitat

Biomes:
Freshwater Marine Wetland Temperate Forest Temperate Rainforest Mediterranean Boreal Forest (Taiga) Alpine +2
Terrain:
Riverine Coastal Mountainous
Elevation: Up to 8858 ft 3 in

Ecological Role

Mobile mesopredator linking marine, estuarine, and freshwater food webs; also an anadromous nutrient/energy vector.

Regulates aquatic and terrestrial-subsidized insect prey in rivers via drift/surface predation Predation on small fishes and crustaceans influences community structure in freshwater and nearshore/marine habitats Transfers marine-derived energy/nutrients into freshwater ecosystems through returning adults, carcasses (when mortality occurs), and excretion-even in iteroparous systems where some individuals survive spawning Serves as prey for higher-level predators (e.g., pinnipeds, otters, piscivorous birds), supporting broader food-web stability

Diet Details

Main Prey:
Aquatic insect larvae Terrestrial insects Other fish Crustaceans Cephalopods

Human Interaction

Domestication Status

Semi domesticated

Steelhead are the sea-migrating form of rainbow trout (Oncorhynchus mykiss). While the species is widely farmed and bred by people as “rainbow trout” (freshwater) and “steelhead” (anadromous), wild river steelhead are usually managed as wild or hatchery origin, not fully domesticated. Hatcheries breed, rear to smolt, and release fish, causing partial human selection and gene flow into rivers.

Danger Level

Low
  • Minor puncture/cuts from fins, gill covers (opercular edge), or hooks/terminal tackle during handling/angling
  • Foodborne illness risk if improperly handled or undercooked (general seafood hygiene risk)
  • Environmental risk during interaction: wading/boating in cold, fast rivers and nearshore surf where steelhead are fished can increase drowning/hypothermia risk (indirect hazard)

As a Pet

Not Suitable as Pet

Legality: Usually not legal or practical to keep Steelhead (Oncorhynchus mykiss) as a household pet. Many U.S. and Canadian areas restrict possession, transport, and stocking; permits and disease rules may be required. Check local fish and wildlife laws.

Care Level: Expert Only

Purchase Cost: $25 - $250
Lifetime Cost: $5,000 - $50,000

Economic Value

Uses:
Recreational angling (high social and tourism value) Hatchery production/stock enhancement (management and mitigation) Aquaculture/food production (marketed as steelhead or rainbow trout depending on system) Cultural and subsistence importance (including Tribal/First Nations fisheries where applicable) Ecosystem services (marine-derived nutrient transfer to freshwater via spawning runs)
Products:
  • Food fish (fresh/frozen fillets; value-added smoked products)
  • Roe
  • Guided sport-fishing services and river/ocean fishing-related tourism spend
  • Hatchery smolts/fingerlings for authorized stocking and mitigation programs

Relationships

Ecological Equivalents 6

Animals that fill a similar ecological role in their ecosystem

Atlantic Salmon
Atlantic Salmon Salmo salar Anadromous salmonid that occupies the same freshwater spawning and marine growth role as steelhead. Adults return to their natal rivers and can spawn more than once. Individuals typically smolt after approximately 1–4 years in freshwater, then spend approximately 1–3 or more years at sea.
Sea Trout
Sea Trout Salmo trutta Ecologically convergent life history: facultative anadromy with coastal marine feeding migrations, returning to rivers to spawn. Repeat spawning (iteroparity) is common in many populations, making them functionally similar to steelhead's iteroparity as opposed to semelparous Pacific salmon (Quinn 2018).
Coho Salmon Oncorhynchus kisutch Overlaps strongly with steelhead in Pacific coastal watersheds: juvenile rearing in streams, smoltification, ocean feeding, and upstream spawning migrations; frequent sympatry and a shared prey base in both freshwater (aquatic insects) and marine phases (forage fishes and krill) (Quinn 2018).
Chinook Salmon
Chinook Salmon Oncorhynchus tshawytscha Shares large-river spawning migrations and marine growth with steelhead. Where they co-occur, adult steelhead and Chinook overlap in migration corridors, use similar thermal refuges, and share predator communities (pinnipeds, orcas) (NOAA Fisheries; Quinn 2018).
Bull Trout
Bull Trout Salvelinus confluentus Coldwater large-river and tributary predator that often shares the same basins. Bull trout can be migratory (fluvial/adfluvial) and occupy overlapping rearing and holding habitats with steelhead, especially in cold, complex river networks (USFWS/Quinn 2018 summaries).
Rainbow Trout
Rainbow Trout Oncorhynchus mykiss Same species as the anadromous form — this is the resident freshwater ecotype (not anadromous). They interbreed, and their offspring may become anadromous or remain in freshwater depending on genetics and environmental conditions. Steelhead (the anadromous rainbow trout) are generally larger, about 51–102 cm in length and 2.3–9.1 kg in weight, with records up to ~25 kg.

While rainbow trout live throughout their lives in freshwater lakes, steelhead live only 1 to 2 years in freshwater before migrating into the ocean. They live in salt water for 2 to 3 years, then return to their freshwater home to spawn. Although they start their lives with the appearance of rainbow trout, migrating into saltwater leads to adaptations in their physical appearance. This makes them grow larger than the trout, also taking on different color patterns.

Native to the western United States, Canada, and Asia, Steelhead are prized among commercial and recreational fishermen alike. They have an appealing taste and are an excellent source of protein, calories, omega-3, and other nutrients for humans and land animals that pursue them. Many recipes are available for cooking these tasty fish. Because they are revered by fishermen and for their nutrition, the fish are now also farmed in regions like California, Washington state, Idaho, British Columbia, and Chile.

Despite the salmon-like attributes and behavior of steelhead, these fish do not die after their first spawning. Instead, they can spawn up to four times before dying.

5 Steelhead Salmon Facts

  • Can hatch rainbow trout or steelhead salmon: The offspring of a steelhead salmon can stay in freshwater as a rainbow trout throughout its life or migrate into saltwater as a steelhead salmon.
  • Do not die upon spawning: Unlike other salmon species, the North American steelhead trout does not die after one spawning and may live for up to 4 sessions of reproduction.
  • 2 “runs” of steelhead each year: Steelhead salmon can return to freshwater for spawning at one of 2 times each year, for either the winter run or summer run of migration.
  • Mating with rainbow trout: Because steelhead salmon and rainbow trout share genetics, one type of fish can fertilize the other’s eggs.
  • Environmental adaptations: Steelhead in the Pacific waters and tributaries of Russia are documented to spawn up to 10 times before dying.

Classification and Scientific Name

The steelhead salmon bears the scientific name Oncorhynchus mykiss. Often called just “steelhead,” other names for this fish include salmon trout and steelhead trout. They are in the order Salmoniformes, family Salmonidae, and genus Oncorhynchus. The steelhead’s genus Oncorhynchus is derived from the Greek word ónkos, meaning “lump” or “bend,” and rhúnkhos, meaning “snout.” Mykiss, from the fish’s scientific name, is the Kamchatka, a Russian word for “trout.”

Steelhead share a scientific name with rainbow trout because these two fish also share genetic makeup. Instead of being two different species, these fish are the same. The exception to this identical makeup is that the fish migrating into saltwater as steelhead show size changes, color changes, and other external adaptations to their new environment. The steelhead also migrate back to their freshwater origin for spawning.

Appearance

Despite being genetically the same, steelhead salmon differ from rainbow trout in appearance. Because of their migration and lifestyle in the ocean, steelhead take on a darker color scheme. They feature a long, silvery body with dark blue and brassy tones. There is generally a pink or red stripe running along the side of the fish’s body, along with a peppering of black dots. Steelhead can measure up to 45 inches long and weigh up to 55 pounds. The name “steelhead” comes from their rounded, silver head.

Closeup of a steelhead trout

Steelhead salmon are silver and grey with dark blue backs or pink and orange specks.

Distribution, Population, and Habitat

Steelhead salmon are native to the western United States, western Canada, and Pacific Asia. They have been introduced to multiple regions of the Americas, such as through farming.

Steelhead salmon are listed as endangered in Southern California. Ten other populations of the fish in the western United States are listed as threatened. Although specific counts of the population are not available, these fish are known to suffer population decreases from habitat loss, commercial fishing, and recreational fishing. If a steelhead salmon becomes trapped within a freshwater habitat and cannot access saltwater, such as after its initial return for spawning, it can survive as a freshwater fish.

Where to Find Steelhead Salmon and How to Catch Them

Steelhead salmon spend the first 1 to 2 years of their lives in or near the freshwater habitat where they are born. They then migrate into their saltwater habitat for the next 2 to 3 years. Returning to their freshwater home for spawning is called a “run” by fishermen and biologists. These runs take place in summer and winter. It is typically during one of the runs that steelhead are easiest to locate and catch.

Fly fishermen prefer to fish for steelhead during the daytime when the fish can see their flies. Spinning fishermen see better results in the evening and at night when the fish are more active.

According to the National Oceanic and Atmospheric Administration, the most common places for fishing for steelhead in the United States include rivers and streams in these regions:

  • California’s Central Valley
  • Central California Coast
  • Lower Columbia River
  • Middle Columbia River
  • Northern California
  • Puget Sound
  • Snake River Basin
  • South-Central California Coast
  • Upper Columbia River
  • Willamette River
  • Middle Columbia River

Steelhead are in high demand for fishermen because the fish provide a thrilling sporting opportunity while also making a great-tasting meal. Steelhead provides healthy calories, Omega-3, protein, and other nutrients. There are a bounty of recipes available online and in cookbooks for this delicious, flaky fish.

Predators and Prey

Steelhead salmon are omnivores. They enjoy a diet of almost any food they can find in their freshwater and saltwater habitats. These fish are also rich in protein, calories, and omega-3, making them a delectable meal for humans and a wide range of other animals.

What eats steelhead salmon?

Because of their light taste and healthy nature, steelhead salmon are one of the most popular fish for chefs, with a bounty of recipes to choose from. In fact, humans catching so many of these fish each year is one of the major factors threatening this species. Other animals vying to eat steelhead salmon are bears, raccoons, birds, otters, lampreys, and other fish.

What do steelhead salmon eat?

A steelhead starts its life as a troutling or fry feeding on zooplankton. As adults, they progress into eating insects from the water and air, mollusks, crustaceans, fish eggs, minnows, and other small fish.

Reproduction and Lifespan

Using its homing behavior, a steelhead salmon leaves its saltwater habitat after 2 to 3 years and returns to its freshwater origin. This journey is often hundreds of miles, taking place in summer or winter. Steelhead use this homing behavior along with the sun’s position and magnetic north to find their birthplace for spawning. It is a miraculous journey that often takes them over many obstacles like rocks, waterfalls, dams, manmade structures, and rapids.

When spawning, the steelhead lays its eggs on the gravel bottom of the freshwater river or stream. The female trout first digs a 6-inch to 14-inch hole in the river bottom to deposit up to 9,000 eggs. A male steelhead then fertilizes the eggs, after which the female buries the fertilized collection under 1 foot of gravel. The eggs remain there until they hatch, 3 weeks to 4 weeks later. The adult steelheads may then return to the ocean to repeat the process for as many as 4 spawning seasons. Steelhead salmon can live up to 11 years in the wild.

Steelhead Salmon in Fishing And Cooking

Steelhead salmon is both a recreational and commercial fishing target. They are caught in purse seine nets and gillnets by commercial fishermen, as well as by individuals using lures, bait, or flies. Indigenous fishermen use spears, harpoons, nets, traps, and fish wheels to catch steelhead during their seasonal runs. Sport fishermen can catch the fish just before winter temperatures drop to freezing in both the air and water. Summer recreational fishing can take place in June, July, and August.

Because steelhead is so similar to salmon and must thrive in the ocean for a period of time, its meat is much like salmon in consistency and color. The tender, pink-orange flesh is both flaky and filling, with a cross between trout and salmon. The most popular way to cook steelhead salmon is like other salmon or trout, using lemon, butter, or oil, and a mix of spices. The fish is wrapped in foil to allow the flavors to permeate while baking in the oven.

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Sources

  1. Biological Diversity / Accessed April 21, 2022
  2. Seapedia / Accessed April 21, 2022
  3. Pacific Salmon Foundation / Accessed April 21, 2022
  4. CBC Radio Canada / Accessed April 21, 2022
  5. Difference Between / Accessed April 21, 2022
  6. Wikipedia / Accessed April 21, 2022
  7. LCSD Wednet / Accessed April 21, 2022
  8. April Vokey / Accessed April 21, 2022
  9. Guidesly / Accessed April 21, 2022
  10. Biological Diversity / Accessed April 21, 2022
  11. NOAA Fisheries / Accessed April 21, 2022
  12. Chefs Resources / Accessed April 21, 2022
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Steelhead Salmon FAQs (Frequently Asked Questions)

Steelhead salmon are native to rivers and streams along the Pacific coast of the United States and Canada, as well as in Asia. The most populous regions in America for these hearty fish are Alaska, Washington and Oregon. In California, populations of steelhead are mostly threatened or endangered.