The bear facts:
The bad news is there are lots of bears in Alaska, the good news is I do not run into many. The exception is streams full of fish or garbage people have left out. The bears in the pictures were not shot with a telephoto lens.
I have spent about 11 months out in the woods of Alaska and have seen a lot of bears but have never had an incident. I am convinced there are two types of bears, city bears and out in the woods bears. Bears that have learned to live off of humans are likely to be a problem, those who work for a living out in the woods are focused on their mission and you are not part of it. Make sure he knows where you are and if he wants to fish in your stream he wins.
Bears are like sharks, 99 percent will leave you alone and one percent gets up on the wrong side of the log and wants to eat you. You have two options:
Guns have the advantage of stopping the bear dead in his tracks as long as you have it ready when he charges you in your fishing hole, you can get off several shots in a few seconds, and you have high velocity big bullets.
Spray has the advantage of always being with you and the disadvantage of a 20 foot range.
I started out with my 12 gauge shotgun with slugs and now use spray. I would prefer to have a big side arm but you cannot take it through Canada. You can take a riffle or a shotgun as long as the barrow is over 18 ½ inches. Guns will insure you get inspected when you go through customs in Canada.