Do You Know: Steelhead?

Drawing: Steelhead in Marine Phase

Quick Facts:

  • Scientific name: Oncorhynchus mykiss.
  • Steelhead were at one time considered a trout species but have been discovered by biologists to be more closely related to Pacific salmon than other trout.
  • The fresh water variant of steelhead is known as rainbow trout.
  • Unlike most other Pacific salmon, some steelhead individuals live to spawn more than once.  

A legendary fighter, the steelhead has a long history in BC’s angling community, although recent population declines in the Georgia Basin area have seen many protective measures come into effect in order to restore dwindling stocks.

Steelhead trout can be found from southern California to the Alaska panhandle, with major spawning grounds centered between Oregon and northern BC in coastal rivers and streams as well as tributaries to major river systems.

Steelhead Migration Map

Steelhead Migration Map

Steelhead live up to nine years and spend between one and three years in freshwater before smolting and entering the ocean. After spawning, many adult steelhead return to the sea and some (up to 20 per cent, mostly females) return to freshwater after recuperation to spawn a second time – unlike other Pacific salmon which die after their first and only spawning. Some individuals can spawn many times and those that repeat spawn are referred to as “kelts”.

Drawing: Steelhead in Spawning Phase

Young steelhead live for one to three full years in fresh water before travelling to the sea as smolts. This migration takes place in spring. Normally two or more summers are spent in the Pacific Ocean before the steelhead return to seek their spawning streams at the age of four or five.

Young steelhead are brightly coloured with tints of red, green-yellow, orange and gold. As they mature they more closely resemble the Atlantic salmon in structure and appearance with heavier spotting. Steehead differ from other Pacific salmon in having a shorter anal fin containing less than 12 supporting rays. When in the sea the body is mainly silvery with a blue back. At spawning time, a band of red colour develops along each side of the body.

Material for this page taken from Underwater World: Pacific Salmon and The Incredible Salmonids (out-of-print), and additionally supplied by the Fisheries and Aquaculture Management Branch of DFO.