Spray
Bear spray.
We are gun people and tend to think that way. "What gun will work best?" There's a lot of evidence that, in the case of the big bears, bear spray works better.
We get to read the cases where the guy walking his dog is attacked and kills the charging bear with his .44 snubbie or somesuch - great for him - but we don't read on these fora about the times the gun didn't work.
I don't live in AK. I do fish there. I carry bear spray which is convenient, accessible and can be worked with one hand. Fortunately, I've never seen a bear up close.
I'm carrying a fishing rod on that walk from the highway through 100 yards of woods down to the river. I wouldn't want to have to unlimber a shotgun.
If, though, I did take a SG, it would have Brenneke slugs in it. I'd stay away from Buckshot - poor penetration and, given the size of the pattern at short distance, you're as apt to miss as with a slug.
Pete