Please everyone, if you are going by Sitka, stop and see Chaik and Killisnoo. They are at the Fortress of the Bear.
Fortress of the Bear is a non-profit bear rescue. They have two bears, brothers, who were rescued after their mother died.
Admission is inexpensive! You see the bears from above their HUGE tank, which is designed as naturally as possible.
As it's just outside of Sitka, you can get a shuttle to there from Tribal Tours. I don't think there's a bookable excursion on the cruise ships. Of course, most of the excursions you purchase on a ship benefit the company that owns the ship, and this wouldn't do that, soo, well.....