Oncorhynchus mykiss (Fishes)

Species Description

Steelhead are a unique type of salmonid. Unlike most other salmonids, Steelhead are iteroparous, which means they can spawn more than once during their lifetime. Furthermore, individuals develop differently depending on their environment. While all O. mykiss hatch in gravel-bottomed, fast-flowing, well-oxygenated rivers and streams, some stay in fresh water all their lives. These fish are called rainbow trout. The Steelhead that migrate to the ocean develop a much more pointed head, become more silvery in color, and typically grow much larger than the rainbow trout that remain in fresh water.

Steelhead can live for as long as 11 years and grow as large as 55 pounds. They may spend as long as seven years in fresh water before migrating downstream to the estuaries as smolts and then into the ocean to feed and mature. Their coloring is quite distinctive: from dark olive green on their backs shading to silvery-white underneath, they sport a pink racing stripe down the side. They are able to tolerate a greater range of water temperatures than other salmon, which may explain their longevity.

The Endangered Species Act permits the federal government to protect imperiled species, subspecies, and distinct population segments. The term “distinct population segment” is a term of art that allows the government to protect portions of an entire species before a particular threat or population decline becomes so severe that the entire species is placed in jeopardy. There are two federally protected distinct population segments of Steelhead in the GGNP: the California Central Valley Steelhead DPS and the Central California Coast DPS.

The California Central Valley steelhead DPS includes all naturally spawned populations of Steelhead in the Sacramento and San Joaquin Rivers and their tributaries, excluding steelhead from San Francisco and San Pablo Bays and their tributaries. They are thus transient in the GGNP, passing through the Park’s marine waters only when traveling from the ocean or to the Steelhead’s natal spawning streams.

Click the image above for a large map of this Steelhead DPS’s range.

Although Steelhead are believed to be more tolerant than other salmonids to fluctuations in habitat conditions, Steelhead populations suffered major declines when large dams were built throughout California, destroying Steelhead spawning habitats. This population was protected as threatened under the Endangered Species Act in 1998, and this decision was affirmed in 2006.

Conservation Action Item

Fund restoration:
Ask public officials for more GGNRA restoration funding

Steelhead need cool, clean waters to reproduce successfully. Water diversions, dams, and water pollution are all lethal to their continued existence.

Please urge your public officials to increase funding for National Parks such as the Golden Gate National Parks, so that they can protect Steelhead through research, education, and restoration of Steelhead habitats.

Big Year Competitors have reported 0 sightings and taken 0 actions to help this species recover so far this year.

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