Ventilation and dive patterns of humpback whales, Megaptera novaeangliae, on their Alaskan feeding grounds

Abstract

Noncalf humpback whales in Frederick Sound, Alaska, were tracked for periods of up to 12.5 h during July through September 1982, 1983, and 1984. Ventilation and dive patterns in presumably undisturbed humpback whales were characterized for six behaviors. Humpbacks appeared to restrict their dives to 150 m and rarely exceeded depths of 120 m, as determined by echo sounder tracings. Duration of dives and surfacings, number of blows per surfacing, and mean blow interval were positively correlated with the depth to which whales dived. Ventilation and dive variable values were significantly elevated in 1983 relative to 1982 and 1984. This was likely due to an increase in the depth of available prey during the 1983 season. The depth to which a feeding whale dove could be related to the depth of the target prey patch with greater than 84% accuracy based upon ventilation and dive variables.