Bear spray LOL. Practice Bear avoidence. If Bears are that big of a problem then only a 870 with 3 inch slugs will help you !
So long as your quick draw is faster than a decent size bear!
I don't know about Black bears but rest are pretty damn fast and like to ambush prey. They are always gonna smell us first.
Most cases I think we're pretty safe, they keep to themselves we keep to ours. It's pretty simple but a lot of noise goes a long way and a long with the spray, you should be more than fine. Be mindful of the surroundings. The only other thing I can think is pick your time of day.
Since bears do their best to avoid people, if you are gonna be in obvious bear territory especially along the river during a feed/spawning. Do go at first light, fishings great but all your gonna do is walk in one, surprise it and thats a worst case scenario.
Oh also... don't be these guys
http://www.youtube.com/watch?v=TakfR9rzKTkNo dogs too.