Both species spend parts of their lives in fresh and saltwater, with most of their adult lives spent in the ocean. Most salmons grow much larger than the smaller steelhead, but steelhead trout are also well known for being some of the hardest fighting and most difficult fish to catch on a fishing pole. Both are considered critical food sources not just for people but for many animals and are excellent indicators of the overall health of an ocean and coastal ecosystem.
Continue reading to learn more about the differences between these two anadromous fish below.
Images credit: NOAA Fisheries
Steelhead Trout vs. Salmon: Main Differences
Steelhead and salmon both have high nutritional value. They are rich in protein and omega-3 fatty acids, which are important for heart and brain health. Some of the main differences are explained as follows:
Appearance: Salmon has a bright silver coloration, with the different species having subtle differences in coloration and spots. Steelheads also have bright coloration but also have a tell-tale pink stripe on their back behind the dorsal fin and, on occasion, can have a brassy or blue coloration.
Size: Salmon tend to be larger than steelhead trout, and in some cases, can be much bigger with king salmon capable of weighing more than 100 pounds while steelhead tends to weigh around seven pounds.
Habitat: Both species are anadromous, meaning that they are born and spawn in freshwater but spend most of their lives in saltwater.
Diet: Salmon eat a variety of prey depending on the type, with their food sources ranging from krill to other fish. Steelhead feeds primarily on mollusks, fish eggs, and minnow-size fish.
Reproduction: Steelhead can return to the river several times to spawn, while most salmon perish after spawning once.
We’ll explore more about these ocean creatures below.
Who Would Win?
In a hypothetical battle between a steelhead trout and a salmon, the outcome would depend heavily on factors like size, age, and the specific salmon species involved.
Steelhead trout, renowned for their fighting spirit and acrobatic leaps, possess remarkable strength and stamina. Their streamlined bodies and powerful tails allow for bursts of speed and agility.
Salmon, depending on the species (Chinook, Coho, etc.), can vary significantly in size and fighting prowess. Larger salmon species like Chinook (King) salmon could overpower a steelhead with sheer size and brute force.
However, a mature steelhead, with its honed fighting instincts and agility, could potentially outmaneuver and tire out a smaller or less experienced salmon.
In a scenario where both fish are of comparable size and experience, the battle could result in a stalemate. Both fish, exhausted and potentially injured, might disengage from the fight.
Ultimately, the victor would be determined by a complex interplay of individual characteristics and environmental circumstances.
Steelhead Trout
Steelhead trout (Oncorhynchus mykiss) possess a streamlined, torpedo-shaped body built for speed and agility in navigating rivers and open waters. Their dorsal fin, located on the back, acts as a stabilizer and rudder, while the adipose fin, a small fleshy fin near the tail, provides additional balance. The pectoral fins, positioned on the sides behind the gills, aid in steering and maneuvering.
The pelvic fins, further back on the underside, contribute to stability and braking. The anal fin, near the tail on the underside, assists with balance and direction changes. Finally, the powerful caudal fin, or tail fin, provides the primary thrust for propulsion and rapid bursts of speed.
Steelhead trout is usually silvery when fully grown, but their coloration can range from brass to blue and even green.
Steelhead trout are also referred to as rainbow trout, but they lead different lifestyles. Rainbow Trout are freshwater fish and steelhead trout are rainbow trout that migrate to the ocean and then return to freshwater to spawn. Many rainbow trout stay in freshwater their entire lives. The factors influencing this decision can include genetics and environmental conditions.
On average, they weigh 6 to 7 pounds though they can reach more than 20 pounds on occasion. The average length is between 18 and 24 inches though bigger specimens can reach 45 inches.
Habitat
Steelheads are born in rivers where they spend the first two years of their life before migrating to saltwater. After three to four years, they return to the rivers to spawn.
They exhibit a remarkable life cycle that encompasses both freshwater and saltwater habitats.
As anadromous fish, they begin life in freshwater streams and rivers, where they hatch and spend their juvenile years feeding and growing.
Once mature, they undergo a physiological transformation called smoltification, preparing them for the ocean. During this stage, their bodies adapt to saltwater, and they embark on an epic migration downstream to the vast expanse of the ocean.
After several years at sea, a homing instinct guides them back to their natal streams to spawn, completing their extraordinary life cycle.
Diet
Steelhead have a varied diet depending on what stage of life they’re in. In the marine environment, steelhead trout roam widely, feeding on a variety of prey like smaller fish, squid, and crustaceans.
As fry, they depend mostly on zooplankton and other small organisms found in the rivers.
Reproduction
After spending years maturing in the ocean, they return to their freshwater birth streams, often traveling hundreds or even thousands of miles. This upstream migration is triggered by environmental cues like changing water temperatures and increased flow. Upon reaching suitable spawning grounds, females excavate nests, known as redds, in the gravel bed using their tails.
Males compete for access to females. Fertilization occurs externally as the female releases her eggs into the redd while the male simultaneously releases his milt (sperm). The fertilized eggs are then covered with gravel, providing protection from predators and ensuring proper oxygenation.
The eggs incubate within the gravel for several weeks to months, depending on water temperature. Upon hatching, the tiny fry emerge and seek refuge in sheltered areas of the stream, gradually developing into the next generation of ocean-bound steelhead.
Threats
Like all anadromous fish, steelhead require several different habitat zones to remain healthy and intact to ensure their survival. Major threats to their native streams have put them at risk in many places.
Dams prevent steelhead from reaching their spawning grounds, while deforestation, agriculture, and climate change are raising river temperatures and lowering the water’s oxygen content.
Salmon
Salmon undergo a dramatic transformation throughout their life cycle, making their appearance quite diverse depending on the stage.
Salmon has a sleek, streamlined body in its oceanic phase for efficient swimming. Their scales shimmer with a metallic silver sheen, providing camouflage against the blue backdrop. The dorsal (top) fin is typically dark, often with black spots, while the lower fins may have a dusky hue.
As salmon embark on their arduous journey back to freshwater to spawn, their bodies undergo significant changes. Their once-silvery scales darken, taking on hues of red, green, or brown.
Males, in particular, develop a pronounced kype, a hooked jaw used for fighting and dominance displays. Their bodies may also become laterally compressed and develop a humped back. This transformation reflects their focus on reproduction and survival in the challenging river environment.
Salmon bodies range from 20 to 60 inches depending on the species.
Most individual species have slight differences, such as in the color of their spots near the base of the tail and the coloration of their gums to help tell them apart.
Habitat
Salmon inhabit a dynamic range of environments throughout their life cycle. Born in freshwater streams with clean, cold water and gravel beds, they embark on an epic journey to the open ocean. There, they mature and roam vast distances.
As the urge to reproduce arises, salmon return to their natal rivers, navigating estuaries and overcoming obstacles to reach their spawning grounds. Their habitat encompasses a diverse array of ecosystems, from pristine mountain streams to the vast expanse of the ocean, reflecting their remarkable adaptability and resilience.
Pink salmon return after two years, while king salmon can remain in the ocean for six years or more.
There are six main species of salmon. These include the Atlantic Salmon, Chinook Salmon, Coho Salmon, Sockeye Salmon, Pink Salmon, and Chum Salmon. However, there are also several subspecies and regional populations, so the total number can vary.
Diet
Salmon fry feeds on various organisms that reside in the river, including small zooplankton and insects. As they grow, larger individuals may start to feed on smaller fry and fish of other species.
Once entering the ocean, most types focus on smaller schooling fish like herring, sand lance, and capelin. Red or sockeye salmon, though, eat plankton primarily as adults, giving their flesh a distinctive reddish color and the inspiration for their name.
Upon returning to their native stream, salmon stop eating.
Reproduction
Salmon reproduction is a fascinating and complex process that begins in freshwater rivers or streams. Adult salmon, after spending several years in the ocean, return to their natal freshwater habitats to spawn. This journey is known as the salmon run.
The female salmon selects a suitable spot and digs a nest, called a redd, where she lays thousands of eggs. The male then fertilizes these eggs with his sperm. After spawning, most species of salmon die, providing nutrients to the ecosystem. The fertilized eggs remain in the redd throughout winter, and by spring, they hatch into alevins – small, yolk-sac larvae.
These alevins eventually develop into fry, then parr, before migrating back to the ocean to mature. Upon hatching, salmon fry are tiny and translucent, relying on camouflage and shelter to avoid predators. As they grow into parr, they develop distinctive vertical bars along their sides, known as “parr marks.” The life cycle then repeats as these mature salmon return to freshwater for reproduction.
Threats
Many of the same threats to steelhead also apply to salmon. Deforestation and dams, specifically in the Pacific Northwest, have caused population numbers to drop or vanish completely in some rivers.
Overfishing further magnifies the problem, and gathering accurate estimates can be difficult when setting quotas.
Ocean Insights: Hear From Our Experts
By Hamna Faizan
Marine Life Researcher and Lecturer, with an MSc in Zoology
FAQs
What’s the difference between farmed and wild salmon?
Farmed salmon is almost always Atlantic salmon as they are more tolerant to being kept in high concentrations. The majority of salmon farms are open net pens, meaning that ocean water is allowed to mix. Research has also shown that salmon farms can have a negative effect on nearby wild salmon stocks, with salmon lice and other harmful parasites jumping from farmed to wild salmon.
Is Steelhead trout the same as salmon?
After being referred to as trout for many years, researchers have determined that steelhead are more closely related to salmon. Despite this, the mixing of the two names has created a lot of confusion, with the most common solution simply calling them steelhead.
What is the largest steelhead or salmon ever caught?
The biggest steelhead or salmon ever caught was a king salmon near the southeast Alaska town of Petersburg in 1949. It was caught in a river fish trap and weighed 126 pounds. The largest salmon ever caught on a traditional fishing pole was landed on the Kenai River in Alaska and weighed 97 pounds.
What eats salmon and steelhead?
Salmon species are an important food source for many animals and are a valuable commercial product for humans. Before reaching the ocean, salmon, and steelhead are food for larger fish, gulls, eagles, other birds, and river otters. Upon entering the ocean, even larger predators like orca whales, seals, and sea lions rely on salmon as their primary food source.
