As I have not studied these issues in depth, I don't purport to understand them very well. However, there is one statistic which is overwhelmingly the most troubling to me, because it clearly points out what we know, namely that that there are many things beyond catching fish (commercially, for sport or for FSC First Nation purposes) that are destroying Chinook salmon populations. The statistic is this one: total fishery mortalities [from fishing] are 16.9% with remaining 83.1% of run going to spawning grounds. Unless, I am mistaken, this suggests it is not overfishing that is the principal cause, or even any cause at all, for this huge decline in the salmon numbers over the last decade or so.
This means that the salmon are not reproducing and/or dying in the ocean without ever being caught by fisherman at rates that will see their permanent demise unless we find out why and do something about if we can. Habitat loss, ocean warming due to climate change, and pollution generally may be the largest reasons for this and if so, I fear that our beloved Chinook are doomed. The changes we all need to make to stop and reverse (where possible) habitat loss, pollution, climate change and ocean warming are for all practical purposes impossible for any meaningful short or even long term recovery to take place. The modern world is built on, and entirely dependent upon, a life of economic consumption that is based on plastic, fossil fuels and other things that are destructive of nature and her bounty. More people want more stuff and the earth pays the price.
This is nobody's fault in particular, but rather the fault of all of us. Until we radically rethink how we live and, most importantly, how we choose to use science and technology to change the planet and our lives, things do not look promising for the natural world, including salmon. Until all of us, worldwide, get a handle on this, debates like the ones on these forums are really just arguments about who should get the last few of a disappearing species. We should instead be looking to save the species, if we can. Even the small steps add up. Use fewer plastic bags, recycle more, burn less fuel, buy less stuff. If millions or billions of people do so, it can make a difference until we figure out how to live without destroying the planet. There are future generations coming and its the least we can do for them.