from the Canadian government website:
http://www.pac.dfo-mpo.gc.ca/fm-gp/s...el-arc-eng.htm
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.