Abundance and feeding ecology of humpback whales (Megaptera novaengliae) in Kodiak, Alaska

Abstract

A feeding aggregation of humpback whales (Megaptera novaeangliae) in the Kodiak Island region has received little previous study. A mark-recapture experiment was conducted in 2001 and 2002 to estimate its abundance. Historical abundance was back-calculated from this estimate, whaling records, and suspected survival and productivity values within a population model. The current population was estimated at 157 whales and the pre-whaling population at 343 whales. Prey consumption by humpback whales was modeled using three methods for two hypothetical diets based on prey availability surveys conducted within the study area and stomach contents of commercially caught whales. By assuming current consumption is proportional to prey availability, the current population removes an estimated 9,600 tons of prey annually. Historical populations may have removed over 19,000 tons of prey annually.