In my opinion the best answer to, "when do they spawn" is "whenever they can". The Salmon seem to be doing pretty well on that river as far as natural reproduction is concerned even WITH all of the blatant snagging that goes on August-October....every year. It's kind of baffling really. Here's what I wanna know. If it was to become limited to daylight fishing only....when does the day begin/end? Who would enforce the policy? The answer to our problems isn't more rules/regs/enforcement. It's angler education! Most of the "problem" folks just don't seem to get it. They have no respect for the resource and in turn don't really care what happens to it.....Whether they are Billy Joe Spin Guy or Thabian the Flycast Master. Educate the masses and teach people how to be good stewards and you will get a more enjoyable resource. I believe it begins with the guides. What happened to paying someone to teach you something instead of paying someone to put you into fish...no matter what it takes. I have taken my fair share of guided trips (mostly before I got my boat) and I have to say the list of guides who provided an educational experience is short. The list of average joes willing to take $300 and hand you a D&C rig and point at a redd and say "have at it" is ENDLESS!!! This is how many of us get our start. Kinda scary eh?
I think alot of people that fish alot begin to lose interest in Salmon fishing. At least when they(salmon) are in the river for a while. I know I have. I am about 1000X happier with a 5 Wt and a #12 globug during salmon season. I'll also take a nice pocket/dropback fish in the spring over a gravel fish anyday. But, there are people who will sit there on polished gravel for hours. That baffles me too. I guess what it all boils down to what are people's individual prioritys. Do you want to spend a quality day in a beautiful place and soak it all in and maybe swim a fish or two? OR do you want to get into fish..no matter what? If the answer is the later then maybe you should take a look at yourself. Do worry too much Hal. I can come up with a list of at least 10-15 other guys my age who feel the exact same way. Us young bucks won't give her up without a fight.
PS As of last summer all boats must have a ranger station permit to float the PM during normal trout season dates. They are limited and usually the canoe liveries buy em all up.