Steelhead

Steelhead are the anadromous (migrating) version of rainbow trout. Rainbow trout are the "land locked" version, and remain in freshwater throughout their life. 

Oncorhynchus mykiss

Identification Characteristics:

  • Head blunt, jaw short - does not extend past the eye
  • Distinct dark spots on dorsal fin
  • Square-shaped tail fin with radiating pattern of spots
  • Often has reddish stripe along sides, gill cover reddish
  • Length up to 45 inches

Steelhead migrate from the ocean into freshwater to spawn, and then can swim back out to the ocean again if they wish. Since steelhead are not semelparous (meaning they do not die after spawning) they are not an "official" Pacific Salmon. But, steelhead are often a favorite of local fishers for their large size and feisty attitude.

Steelhead have the most complex life history patterns of any Pacific salmonid species (Shapovalov and Taft 1954). In Washington, there are two major run types, winter and summer steelhead. Winter steelhead adults begin river entry in a mature reproductive state in December and generally spawn from February through May. Summer steelhead adults enter the river from about May through October with spawning from about February through April. They enter the river in an immature state and require several months to mature (Burgner et al 1992). Summer steelhead usually spawn farther upstream than winter stocks (Withler 1966) and dominate inland areas such as the Columbia Basin. However, the coastal streams support more winter steelhead populations. 

Juvenile steelhead can either migrate to sea or remain in freshwater as rainbow or redband trout. In Washington, those that are anadromous usually spend 1-3 years in freshwater, with the greatest proportion spending two years (Busby et al. 1996). Because of this, steelhead rely heavily on the freshwater habitat and are present in streams all year long.

Photos from Inland Fishes of Washington by Whitney and Wydoski, © 1979 University of Washington Press. Reprinted by permission of the University of Washington Press.