The Dolphin Institute - Dolphin Research Summaries

(C) 1986 University of Hawaii

Five studies are presented describing pod characteristics, general behavior, and behavior in the presence of vessels of humpback whales in Hawaii. A sixth study on the timing of migration by humpbacks is presented as an appendix.

Study I: Pod Characteristics. Aerial surveys of the eastern Hawaiian Islands, 1977 – 1980, indicated that pod sizes were small (mean = 2.45), increased over the course of the season, and were smaller on the island of Hawaii than in other areas. Calves were most common at Maui, Penguin Bank, and Kauai. The percentage of calves declined over the four years of the study, from 9.7% – 6.1%.

Study II: Pod Characteristics. Shore observations from west Maui, during 1983 and 1984, yielded pod sizes slightly smaller on average than those indicated by aerial surveys. Unlike previous reports, no trend was found for increasing pod size over the course of the season.

Study III: Effect of Vessel Numbers on the Distribution of Humpbacks. There was no significant correlation between numbers of vessels and numbers of humpbacks whales in the Olowalu area of West Maui. It was suggested that this was attributable to the transitory nature of humpbacks in Hawaii

Study IV: Behavior and Response to Vessels, Aerial Surveys. Swimming speed was found to increase with pod size and the number of vessels within .25 miles of a pod. Pods with calves swam at slower speeds and engaged in more contractual behavior than did pods without calves

Study V: Behavior and Response to Vessels, Shore Observations. Larger pods were associated with higher rates of social exchange, head lunges, rapid swimming, and higher blow rates. Calf pods were associated with lower rates of social exchange, fewer fluke-up dives, slower swimming speeds, and higher rates of no-blow rises, fluke-down dives, and head rises. Affiliations were associated with breaching and head lunges, while disaffiliations were associated only with head lunges. Swimming speed, social exchange, and aerial behavior were all higher in Hawaii than in Alaska. Blow rates increased with physical case study showed that nursing was associated with fluke extensions by the mother. Vessel numbers, speed, proximity, and direction changes were generally associated with higher swimming speeds, higher rates of affiliations, disaffiliations, lateral fluke displays, no-blow rises, blows, and peduncle slaps. These vessel characteristics were also associated with lower rates of flipper extensions and flipper slaps. In general, smaller pods and pods with a calf were more affected than larger pods

Study VI: A Magnetic Correlate of Migration. The migration timing of humpback whales was found to be associated with changes in atmospheric magnetic characteristics.

Bauer, G. B. (1986). The behavior of humpback whales in Hawaii and modification of behavior induced by human intervention. Unpublished doctoral dissertation, University of Hawaii, Honolulu

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