I live in the heart of bear country and the only thing I have found to work is a baited electric fence. I've had bears scale the side of a building to get to hives on the roof, climb of a 25ft high roof top, and rip thru 8ft high fencing. I have also found out that all electric fences are not created equal, and you get what you pay for.....go figure. :roll:
I have found Parmak fencers to work well and they have become my fencer of choice. I have had their solar ones covered in snow for months at a time and still continue to work. On the other hand I had (gave it away now) a Zareba solar one that couldn't go more than a few cloudy days before dying.
Baiting the fence is critical. If they don't get zapped on the nose/tongue they will just walk right through the fence as their fur insulates them from the fence. I take strips of metal screening and fold it around the fence and smear peanut butter on it.
It doesn't take more than a few strands of baited wire to protect your hives. For what it is worth, a few years ago I had 4 bears in my yard and they got into my chicken coop killed a couple of guineas hens and drug out a bag of feed. The kept coming back for days trying to tear the door of the coop until I finally put a single baited wire around it. Didn't have any trouble after that. All during this time, I had a trailer of bees not more than 50ft away that was never touched.