Ocean conditions are the driving factor in salmon returns, habitat is a driving factor in maintaining some sort of population base. No habitat = no returns, marginal-to excellent habitat, ocean conditions dictate returns.
I couldn't agree more with this statement...pristine habitat, no overharvest, and good ocean conditions will result in excellent abundance...pristine habitat and no overharvest during periods of poor ocean conditions will preserve the functionality of the population while it waits for the ocean conditions to turn around...in the case of steelhead, the population may even spend more of its productivity creating resident rainbows to avoid the ocean altogether. When the ocean changes for the better, they then contribute to the now more advantageous anadromous life form.
Kill off the buffer of resident rainbows and good river habitat, and there won't be enough left to take advantage of good ocean conditions when they do return.
Fish populations going through magnitude ten natural cycles boom and bust has always been part of the natural environmental conditions...but kicking 'em when they're down during the bust part of the cycle might end any chance of having that boom when things turn around...
Fish on...
Todd
P.S. When I hear of the predator problems on the Columbia River system...terns, cormorants, mergansers, bass, walleye, sea lions, whatever...I call that a "habitat" problem...there wouldn't be a bunch of warmwater fish eating salmon fry if there weren't dams there creating the habitat for the predator fish to flourish in. There wouldn't be a bottleneck of sea lions at Bonneville if there wasn't a bottleneck created there to pin the fish up against, and there wouldn't be a tern problem if we didn't dredge the channel out and make artificial islands for them to nest on.
The cormorant and merganser problem can also be equated with a hatchery problem...wild fish emerge and migrate at all different times and places, but clouds of hatchery fish coming down six inches under the surface every time they release a few million at once attracts those birds in a way that they never would have been attracted before.
Those predator problems are not being addressed properly, in my opinion...getting rid of the predators is getting rid of the symptom...the actual problem is what created an environment friendly to those predators.