Headed for the Lady in Red. Your looking at a time frame that is narrow by natures terms. You need to look at 15 to 20 life cycles of the creature. Your point is well taken and was mine until CM and PS made me look to the time thing and out of the present and human terms.

Your stuck in your view of time in human terms rather than natures, and your going to be be very disappointed. As to the CR nothing is natural. Dams, irrigation, cities, all have altered things ( and the power dams and people are going no place ) so that nothing mirrors the natural processes other than the act of reproduction, and that is limited.

The simple fact is salmonids and modern human society are incompatible. It is only a question of how many natural spawning populations will remain 100 years from now that is in doubt. What is not in doubt is that very few will remain and mixed stock ocean harvest will no longer exist.