hike..another noise maker would be the small air horns that are sold to attract attention or warnings when power boating.
canoe trippers have taken to attaching them to a PFD as part of a ditch kit. i have been told that just the WHOOSH!! of a pepper sprayer will chase a bear.
however as long as i have the 357 i may as well find a way to use it as a non lethal bear defense with the lethal one as a last resort.
about that knee of yours.the best real bit of survival advice i can offer is not about 357's,fire lighters,water filters or BOB's and EDC's it's that getting a painful knee fixed could be a life saver.
on my last canoe trip i felt 20,ok 10,years younger.i could carry 35-45 pound packs over portages without rest stops and was pain free.
faced with a real survival problem like a ditched canoe and swim to shore doing that without the nasty/severe pain in my knee joint could make a huge problem a doable one.
always dealing with the knee was like dragging a cement block around and trying to run from a pack of zombies or climb over earthquake damage could make survival iffy.
i would get it replaced sooner than later.