ADULT FISH COUNT
a count of adult fishes passing by a fish-viewing window. Such windows can be placed at the upstream end of fish ladders on dams. Observers count the number of fish according to pre-set criteria, e.g. by species and size, for 50 minutes of every hour for 16 hours per day. Extrapolations can then be made for times when fish are not observed. Separate counts can be made for adults and jacks (precocious male salmonids that can be identified by their smaller size)