I used to do some fishing guiding and outfitting in Southeast Alaska, and I know that the most common bear defense was 12ga 00 or 000 magnum buckshot alternating with slugs, along with .44's carried on the belt, in a shoulder holster or in the dry-bag.
For myself, I always wore a 4" 629 and carried a shotgun full of Brenneke's. Over many well lubricated late evening sessions with other experienced hands, the consensus always seemed to be that the shotgun was sufficient to "repel boarders" (i.e., shoot a bear and keep it from getting to you), while the .44 was carried more in the hopes that everybody else would have one, too. Follow me on this line of thought:
Brown Bears are horribly inefficient predators, and do not kill quickly or cleanly. Compare bear attacks with lion and leopard attacks, and you will see that people mauled by bears are usually able to survive the initial attack, if they are rescued within minutes or sometimes hours, whereas those attacked by cats are usually DRT in moments. If you are traveling in a group (common when fishing), then you will take comfort in the fact that almost everyone will have a .44 and will be able to drive off and kill the bear, eventually, even if they have to empty every revolver in the group. If you are traveling solo, however, or with a group that does not carry guns (newbies, paying clients, whatever), then you keep your 12ga close to hand at all times, because you will not have the luxury of rolling up in a ball and waiting for the hail of bullets to settle Mr. Bear's hash.
In several decades of travel to Southeast Alaska, I've never had to shoot a bear. I've sort of shot close to one a couple of times, just to get his attention and persuade him to pick a different hobby, but haven't been forced to kill one. When I'm fishing with friends, I take comfort in knowing that those in my group can shoot reasonably straight and that they carry sidearms I trust to be reliable and stoked with good ammo ('cause I clean everybody's guns, and I provide the ammo). In those circumstances, I'll leave the shotgun with the raft or driftboat hundreds of yards or even a mile or two away. When traveling solo, or with my better half (who doesn't shoot a heavy recoiling sidearm very well), I always carry my nickel plated coachgun loaded with two 3" brenneke's, and I'm never more than a couple of feet away from it.
Just my two cents worth. Your Mileage May Vary. Void where taxed or prohibited by law, and so forth.