One variable rarely discussed is the unnatural concentrations of fish created by hatchery releases. Predators get used to where their food will be and when. If there are wild fish in the vicinity they are at greater risk. This may be more meaningful/problematic in the Columbia basin but predators are predators regardless. If we concentrate a food source it makes it easier and more attractive for the predators...any wild fish (alevin, fry, parr or smolt) that happen to be in the vicinity is at much greater risk, and hatchery smolt are predators. Each spring on the Klickitat the hatchery semi's pull through town accompanied by flocks of seagulls. The seagulls and fish eating ducks follow the mass of hatchery smolts down the Klickitat and into the Columbia where they continue to follow, and of course the pikeminnows are waiting also. Any wild fish in the vicinity is at greater risk. I'd bet >50% of the hatchery releases are consumed well before they get to the Pacific and if there are wild fish in the mix they get consumed at a similar rate...it's PURE economics for the predators.