Ecology, Status and Stock Identity of Beluga Whales, Delphinapterus Leucas, in Yakutat Bay, Alaska

摘要

A field project was conducted in the summer of 2005 to study the little known group of beluga whales, Delphinapterus leucas, in Yakutat Bay, Alaska. A genetic investigation was also initiated to establish the origins, genetic composition and stock status of these whales, and a thorough review of documented sightings was undertaken. This study was conducted in association with a separate study of Traditional Ecological Knowledge (TEK) of beluga whales in the Yakutat area. A combination of aerial, shore- and boat-based surveys sighted beluga whales on most days between 5/3/05 and 5/19/05. Most sightings were in the upper reaches of Disenchantment Bay, and the maximum number observed was 12 whales. Group size ranged from 1-12 individuals. Group composition varied from all adult groups to mixed-age groups. No newborn calves were observed. Three discrete high-use areas were identified in the intensively surveyed area of upper Disenchantment Bay. The first, a remote, protected bay located between the Hubbard and Turner Glaciers, appeared to be used primarily for rest, socialization and possibly molting. The second, the waters at the face of the Turner Glacier, appeared to be an important feeding location. The third was a narrow strip along the shore between the first two and appeared to be primarily a transit corridor. Although tide and time-of-day may have played a role in beluga whale behavior, no clear diurnal or tidal patterns were evident. Other areas may have been used beyond the observation range of this study.