Where will you be??? Any wildlife viewing will require tours- if you want more than a brief distant glance. Interior- Denali Park is the best bargain for land animals. Consider the shuttle to Eielson at the least you need the Tundra Wilderness tour. Humpbacks- whale watching out of Juneau. (orcas only come in every 5-10 days) if you want orcas- tour out of Victoria BC, or Friday Harbor Wa. You can take a chance out of Ketchikan for bear watching- you are early in the season. Overall- binoculars are necessary- wide angle for any marine wildife spotting.
As Karn said, it depends on where you will be, what excursions you take, and how much time you put in to it. From the ship, you cannot expect to see that much, except for a whale on other marine wildlife from a distance. It you take whalewatching tours from Juneua or Seward, you will see humpbacks and hopefully orcas, harbor seals, sea otters, you may spot sheep or goats on the hill tops, could see a bear on the beach or shore, moose can be anywhere. If you go to Denali Natl Park and spend a day or two, you could take the shuttle or tundra wildlife tour. These are 6-9 hour school bus trips down a gravel one way road into denali and back out. If there, you should see grizzlies, caribou, goats, sheep, maybe a wolf, moose. We have seen hundreds of these on a one day trip including 8-10 bears, some right near bus.
So it depends where you are going and what you book. Read old posts on this board and cruisecritic, lots of questions and info on same subject.