Steelhead

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Classification

Steelhead: Oncorhynchus mykiss [1]
Kingdom Animalia
Phylum Chordata
Class Actinopterygii
Order Salmoniformes
Family Salmonidae
Genus Oncorhynchus
Species mykiss

Steelhead Life History

Life cycle of Salmon and Steelhead [2]

Steelhead (Oncorhynchus mykiss) is the name for anadromous rainbow trout. Generally, anadromous fish spend the majority of their lives in the ocean and spawn in fresh water, but mature steelhead have been observed to remain in freshwater environments for multiple seasons. Steelhead are distinct among Pacific salmonid species because they are both anadromous and iteroparous. Iteroparous fish are capable of reproducing multiple times over the course of their lifespans.

Steelhead exhibit a wide range of life histories and development is dependent on the local environment [3]. After hatching, juvenile steelhead generally spend 2-4 years maturing before migrating to the ocean. However, on occasion an individual will remain in freshwater environment for up to 7 years before moving to an estuarine environment to mature. Mature adults do not reproduce every year; when they do, they will return to the stream of their birth. The maximum lifespan for steelhead is estimated to be around 11 years [4].

Habitat

Steelhead critical habitat[4]

Steelhead are capable of surviving in a wide range of habitats, but prefer streams with a dissolved oxygen content of at least 7 ppm. They spawn in fast flowing streams with a gravel substrate with low silt content.

In the United States, steelhead are found along the entire west coast. NOAA has designated much of the California coast, as well as sections of Oregon, Washington, and Idaho as Critical Habitat [4].

Conservation

Steelhead were first listed as threatened under the Endangered Species Act (ESA) in 1998 [5]. The complex life cycle for steelhead provide a number of management challenges.

Links

References

  1. NOAA fisheries http://www.westcoast.fisheries.noaa.gov/stories/2014/14_stearns_dam_removal.html
  2. UC Davis Salmon and Steelhead life history
  3. Satterthwaite WH, Beaks MP, Collins EM, Swank DR, Merz JE, Titus RG, Sogard SM, Mangel M. 2009. Steelhead life history on California's Central Coast: insights from a state-dependent model. Transactions of the American Fisheries Society 138:532-548
  4. 4.0 4.1 4.2 NOAA Fisheries: Steelhead trout information http://www.nmfs.noaa.gov/pr/species/fish/steelheadtrout.htm
  5. U.S. Fish and Wildlife Species Profile: steelhead http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=E08D

Disclaimer

This page may contain student work completed as part of assigned coursework. It may not be accurate. It does not necessary reflect the opinion or policy of CSUMB, its staff, or students.