I'd like to know a little more about the conditions and time of year.. Perhaps it was mentioned but I didn't see it.

I know that I fish a small stream in SW WA that gets a great run of hatchery and wild summer steelhead. During this fishery when most fish come back (April-August) river temps rise as the season progresses. It's not uncommon in June-August to have river temps touching 60+ degrees. A friend of mine and myself are extreme egg/bait/lightline fisherman that catch and release 125-175 summerruns a season in this (creek)...

The river usually runs on average180-300 cfs and naturally with low water runs extremely clear. In all the years I've fished I can't remember a single time I've ever seen a dead summerrun in the river. One would think even if you had a 5% mortality ratio you'd have to see dead fish occasionally, but I honestly haven't... Of the 125-175 fish a year with bait many of them are hooked deep in the gills etc and with light line larger fish are played to some bit of exaustion. We have hundreds and hundreds of pictures of fish that we had taken out of the water for 30-45 seconds and I still have never seen a dead fish...

I also know that there aren't many predators along the river due to private property and many of houses. But if predators were a issue you'd still see remains of fish somewhere..

Perhaps someone could help explain these results...

Oh and I'm not a biologist but am a fish freak that's done nothing but study fish and lifecycles of them. I care a ton about our fisheries and so do all that I fish with.
Keith