Rookie question

[WT]

I have been fly fishing for a number of year, but this will be the first year that I attempt to go steelheading and I was wondering if anyone could explain the difference to me between a steelhead and a RB trout. Especially the difference between a "half-pounder."

[Bill Kiene semi-retired]

A Rainbow trout that has access to the ocean is a Steelhead trout.

They go down stream to the ocean and feed on the vast food sources there which helps them grow faster.

We think 'Half-pounders' are just a smaller Steelhead that actually didn't really get out into the ocean. Maybe they go down into the brackish water of the bays where they can feed on small grass shrimp which are the size of tiny cocktail shrimp.

Jeff Putnam is going to have some free one hour demonstrations on how to fly fish for Half-pounder Steelhead in the Lower American River.

[WT]

Thanks Bill. I will have to check out those classes that Jeff is going to be putting on.

As a follow up question, are there any visiable differences or identification markers which would alert someone to the fact that what they have caught is a 20 inch steelhead and not a 20 inch RB?

[Bill Kiene semi-retired]

I don't think we have many 20 inch Rainbows in the river. but we would never be sure.

Right now the half-pounders should have their ocean colors with dark backs, silver sides and white bellies.

After a month or two in the river they might look for like big Rainbow trout.

[WT]

Thanks Bill for the information

[bubzilla]

"Half-Pounder" is a term that is misused quite a bit, but that actually has a very specific scientific meaning. Half-pounders are sexually immature steelhead that have been out to the Pacific, resided in the salt for a short time, and then returned on a false spawning run only to return to the sea again until they reach maturity. After that, they come back in as adults. As a result of this life history, the adults on rivers with half-pounders tend to be somewhat undersized from other systems that do not have half-pounder life history. Although the term is used extensively, there are only a handful of rivers with true half-pounder runs, the best known being the Klamath and Rogue. Lots of people will refer to small steelhead as half-pounders, but that is not necessarily true--particularly unless the fish in question is caught on one of the very few rivers with half-pounder life history. In Oregon, for example, the Rogue is the only system, of all the dozens of rivers in Oregon with steelhead that has half-pounders.

There was an article in Fly Fisherman a few years back focusing on the fishing opportunities in Northern California that described the science behind half-pounders. One of the theories discussed, which would explain the very limited distribution of half-pounders as an exception to typical steelhead life history, was the annual presence of the Humbolt Upwelling in the Pacific off of the coast of Northern California/Southern Oregon. The theory was that the poor ocean conditions for steelhead created by this phenomena drove the fish back into the rivers for shelter each fall. Once it subsided, they were able to return to the ocean. Interesting theory, but I do not believe we are sure what causes the behavior for sure. We do know it appears to be highly unique to a very limited number or rivers.