RE: Bow black bear
As stated above, it is illegal to possess a hand gun in Canada. It is also illegal to take pepper spray into Canada. It is however legal to take bear maize. I was checked last year and since the can said bear on it it was legal. Doesn't make a lot of sense to me, but thats how the border patrol explained it to me.
I wouldn't worry about taking a gun for a backup. My experience has been that black bears are more interested in running away than at you. You just need to watch out for sows w/ cubs as they are protective. I am assuming your hunting w/ an outfitter and he should be able to fill you in on any safety requirements. The one I hunted w/ would always take a slug gun along when tracking. He indicated that in 20+ years of guiding he had never used it.