Both species spend parts of their lives in both freshwater and saltwater, with the majority of their adult lives spent in the ocean. Most types of salmon 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 very important food sources not just for people but for many animals and are excellent indicators of the overall health of an ocean and coastal ecosystem.
You can learn more about the differences between these two anadromous fish below.
Left image credit: Oregon State University / Right image credit: Katmai National Park & Preserve
Main Differences Between Steelhead Trout and Salmon
- 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.
Left image credit: Fungus Guy / Right image credit: (xxxx missing)
Steelhead Trout
Appearance
Also known as rainbow trout, Steelhead trout is usually silvery when fully grown, but their coloration can range from brass to blue and even green.
Image credit: Lisac Mark, USFWS
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 and 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.
Diet
Steelhead have a varied diet depending on what stage of life they’re in. As fry, they subsist mostly on zooplankton and other small organisms found in the rivers.
By the time they migrate to the ocean, they’ve moved on to larger prey sources such as crustaceans, mollusks, and small fish.
Threats
Like all anadromous fish, steelhead requires 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
Appearance
Salmon have a bright, silvery complexion as adults with long, muscular bodies ranging 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.
When they return to the river to spawn, Salmon quickly change to colors of red, orange, pink, or brown, depending on the species. The snout of the males will become more prominent and hooked to go along with several sharp teeth in preparation for competing with each other for a mate.
Habitat
Salmon are born in rivers, where they spend the first one to three years, depending on the species. The time they spend in the ocean also depends on the species. Pink salmon return after two years, while king salmon can remain in the ocean for six years or more.
Image credit: Bureau of Land Management
Salmon will return to the same river they were born in, timing their return with large tidal fluctuations to aid them in their trip upstream.
Diet
Salmon fry will feed 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.
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.
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.
