Black bears are found in most forested parts of Alaska [1], though not on certain Southeast Alaskan islands. They are distinguished from grizzlies and brown bears by their size (much smaller), the shape of their face (much narrower), and the lack of a shoulder hump. Black bears are actually more dangerous to people than grizzlies: There have been more attacks and maulings in Alaska by black bears than by brown.
Two places on Tongass National Forest [2] offer a fine opportunity to watch black bears as they catch salmon: Anan Creek Bear Observatory near Wrangell [3] and Margaret Creek Fish Ladder near Ketchikan [4].
Links:
[1] http://www.moon.com/destinations/alaska
[2] http://www.moon.com/destinations/alaska/southeast-alaska/tongass-national-forest
[3] http://www.moon.com/destinations/alaska/southeast-alaska/wrangell/sights/anan-creek-wildlife-viewing-site
[4] http://www.moon.com/destinations/alaska/southeast-alaska/ketchikan