At the hatchery of the river I usually fish I always see soreback steelhead. Whats the deal with that? is it only nates that don't die? Also what would happen if these potientially "Rotter Fish" spawned with nates?
This has got me confused.
Tyler

Not all steelhead return to the sea after spawning. A large number actually dies. I'm not sure why this occurs but it's probably a combination of age and perhaps not getting enough valuable minerals and nutrients when feeding prior to spawning.

in the ball park of 7-15% of steelies spawn more than once

This is what happens when there slime gets rubbed off of them. It is a protective coating from infections. That is why you need to be extra careful when releasing the natives.

I see the same thing with natives in the spring when the rivers first open.Had one that hung around in a canyon pool well into jully.I knicked named her old moldy!Used to feed her worms!

The spawning run is very stressful to a steelhead and when they're near spawning time, their immune system is suppressed, so they are very prone to infection. What you are seeing are opportunistic fungal infections. The nates are usually genetically more immunocompetant (resistant) to the infectious agents in a particular river, and tend to suffer less frequently from these infections.