Here a betime story for you, all about this little problem:

Once upon a time there was a brilliant scientist named W.E Ricker, who deduced that the survival of the eggs from each fish declined when too many spawned, and so he developed a mystic curve who's apex showed the exact density of fish spawning that produced the highest survival of the eggs from each fish. This density he converted into numbers for each river that were optimum, and decreed that every fish that escaped above this number was a waste and should be harvested. This magical point was enthroned as the God MSY (maximum sustainable yield), drummed into the heads of all educated bioligists, and used to this day to manage fish returns. When the WDFW/Tribal High Priests of fish biology decree that a river is at maximum escapement, they mean that it is at MSY, thus all is well.

Problem is, W.E. in all his brilliance never bothered to try to figure out why, if it was bad for the fish to escape above MSY, they continued to do so when left to their own hedonistic devices. Even the most simple pagan ecologist knows that species do not evolve undesirable traits and survive for very long. So if overescapement is undesirable, why do salmon do it?

The obvious answer is this: What to our eyes appears to be gross overescapement is a desirable trait and ensures survival, thusly: The first to spawn clean the silt out of the gravel so that the majority of subsequent spawners have high quality incubation conditions. In times of ocean disaster and low return the first fish use only the best sites remaining from the previous year's excessive activities. In times of extreme floods the abundance of late spawners still have a chance to keep the run going. Predators (natural ones anyway) are satiated and leave most of the fish alone. Those salmon who's eggs are dug up nourish next year's young and all their diverse relatives (cutts, resident rainbow, steelhead smolts, dollies, etc). And because of the poor nutrient conditions in high rainfall river systems that salmon prefer, all those tons of dead fish fertilize the entire ecosystem and grow all of the invertebrates that their young need to survive and reach the ocean in high numbers and prime condition. Plus a number of other good things pagan ecologists haven't thought of yet and that High Priests of biology would never even consider, as it defiles the God MSY.

The river on MSY therefore has dirty gravel so egg survival plummets, as there are no good sites left without intersticeis in the gravel plugged by years of silt. If the river floods all are wiped out. Natural predators are reviled because they are destroying the run, which the unnatural predators sanctioned by the High Priests have already reduced to MSY, and are harrassed and hunted by the unnatural predators who are the only beings capable of holding the run down to MSY. All the resident fish die out even before ESA can notice them, and most of the lovely cutts and dollies live in remnants only on ESA because there is nothing else to eat. And everyone's remaining offspring starve in the unproductive river and enter the ocean undersized, in poor condition, and in low numbers, as there are no nutrients in the ecosystem.

Sorry, they did not all live happily ever after. In the end very few if any lived at all.