The steelhead trout is an anadromous fish, meaning it returns to fresh water rivers to spawn. The scales of the steelhead shine flecks of silver with a gray spotted back from head to tail and an intensely white belly; the two colors separated by a hint of opalescent pink. Steelhead trout is one of the most popular fish for recreational fishing, a major industry in Washington State.
The steelhead trout (Salmo gairdnerii) was adopted by the Legislature as a state symbol in 1969.
Like salmon, steelhead are anadromous: they return to their original hatching ground to spawn. Steelhead rejuvenate after spawning, so they may return to the oceans to start the anadromous cycle once again. The steelhead smolts (immature or young fish) usually remain in the river for about a year before heading to sea, whereas salmon typically return to the seas as smolts. Different populations of steelheads migrate upriver at different times of the year. "Summer-run steelhead" migrate between May and October, before their reproductive organs are fully mature. They mature in freshwater before spawning in the spring. "Winter-run steelhead" mature fully in the ocean before migrating, between November and April, and spawn shortly after returning. Similar to Atlantic salmon, but unlike their Pacific Oncorhynchus kin, steelhead are iteroparous and may make several spawning trips between fresh and salt water. The maximum recorded life-span for a rainbow trout is 11 years.[4] Salmon is often sold as a replacement because they taste similar
Rainbow trout are predators with a varied diet, and will eat nearly anything they can grab, in contrast to the legendary, selective image people often have of the fish's dietary habits. Rainbows are not quite as piscivorous or aggressive as the brown trout or lake trout (char). When young, insects make up a large portion of the diet, smaller fish (up to 1/3 of their length), along with crayfish and other crustaceans make up the remainder. As they grow, though, the proportion of fish increases in most all populations. Some lake dwelling lines may become planktonic feeders. While in flowing waters populated with salmon, trout will eat salmon eggs, alvein, fry, smolt and even salmon carcasses
Rainbow trout and steelhead are both highly desired food and sportfish. A number of angling methods are commonly employed. Rainbow trout are a popular target for fly fishers. Spinners, spoons, and small crankbaits can also be used productively, either casting or trolling. Rainbow trout can also be caught on live bait; nightcrawlers, trout worms, and minnows are popular and effective choices.
Steelhead trout have declined due to a number of human and natural causes. The U.S. National Marine Fisheries Service has a detailed description of threats. Steelhead that spawn in Southern California streams (south of Point Conception) have been affected by habitat loss due to dams, confinement of streams in concrete channels, water pollution, groundwater pumping, urban heat island effects, and other byproducts of urbanization.
The U.S. National Marine Fisheries Service has identified 15 populations, called Distinct Population Segments(DPSs), of steelhead trout in Washington, Oregon and California.[7][8] Eleven of these DPSs are listed under the U.S. Endangered Species Act (ESA).[9] One DPS on the Oregon Coast is designated a U.S. Species of Concern. Species of Concern are those species about which the National Marine Fisheries Service has some concerns regarding status and threats, but for which insufficient information is available to indicate a need to list the species under the ESA.
The rainbow trout is susceptible to enteric redmouth disease. There has been considerable research conducted on redmouth disease, as its implications for rainbow trout farmers are significant. The disease does not affect humans.[10]
Rainbow trout, and subspecies thereof, are currently EPA approved indicator species for acute fresh water aquatic toxicity testing.
They are farmed in many countries throughout the world. Since the 1950s commercial production has grown exponentially, particularly in Europe and recently in Chile. Worldwide, in 2007, 604,695 tonnes of farmed salmon trout were harvested with a value of 2.589 billion USD dollars.[6] The largest producer is Chile. In Chile and Norway, the ocean cage production of steelhead has expanded to supply export markets. Inland production of rainbow trout to supply domestic markets has increased strongly in countries such as Italy, France, Germany, Denmark and Spain. Other significant producing countries include the USA, Iran, Germany and the UK.[6]
There are tribal commercial fisheries for steelhead in the Puget Sound, the Washington Coast and in the Columbia River.
