NMML Harbor Porpoise Aerial Survey, Alaska Peninsula, Replicate 1, 1992

Employing a Twin Otter as the survey platform, the first of two identical saw-tooth tracklines was flown at an altitude of 152.2 m (500ft) and at an airspeed of 100 kn. Line-transect methodology was used, and only those observations made during optimal conditions were analyzed.

Density of harbor porpoises was calculated using line transect estimates based on perpendicular distances of sightings to the cruise track of the airplane. On average, porpoise group size and density off the south side of the Alaska Peninsula was 1.1 (SE = .10) and 2.03 groups/100 km^2 (SE=1.65).