Steelhead trout and Rainbow trout are the same species of fish (Oncorhynchus Mykiss). However, Rainbow trout are only found in freshwater whereas the Steelhead trout go out to sea, making them anadromous. This dual pattern (being in both salt and freshwater) of the Steelhead or Rainbow Trout makes the species as a whole more adaptable to changes that occur in their environment than fish that only stay in one system.There are a number of variances between the anadromous and freshwater form of the species, but the most observable difference might be in the roe they produce. Rainbow trout produce smaller firmer eggs with milder flavor, while Steelhead have larger beads that are more similar to salmon caviar than freshwater trout.
Here's some key information on the Rainbow (Steelhead) Trout:
Another name for the Rainbow trout is Steelhead trout or Sea-run Rainbow trout.
The average size of the Rainbow trout at maturity is between 8-11 lbs. up to a recorded 40 lbs.
Rainbow trout spawn in the spring. They usually prefer fast moving currents but they tend to spawn in water that is calmer and easier to dig into the river bed.
Similar to the Chinook Salmon, Rainbow trout have both summer spawning runs and winter spawning runs.
Unlike Pacific Salmon, Rainbow trout don't necessarily die after spawning and can spawn more than once.
Spawning runs in the winter are closer to the ocean and require less travel time than summer runs.
After hatching, the developing trout will remain in the gravel for a little more than a month. During this time, they are called alevins.
Once the newly developed Rainbow trout leave the gravel, they are called fry.
Alevin - The lifestage of a salmonid between egg and fry. An alevin looks like a fish with a huge pot belly, which is the remaining egg sac. Alevin remain protected in the gravel riverbed, obtaining nutrition from the egg sac until they are large enough to fend for themselves in the stream.
Anadromous - Fish that live part or the majority of their lives in saltwater, but return to freshwater to spawn.
Fry - A juvenile salmonid that has absorbed its egg sac and is rearing in the stream; the stage of development between an alevin and a parr.
Parr - Also known as fingerling. A large juvenile salmonid, one between a fry and a smolt.
Smolt - A juvenile salmonid which has reared in-stream and is preparing to enter the ocean. Smolts exchange the spotted camouflage of the stream for the chrome of the ocean.
Substrate - The material which comprises a stream bottom.