Individual Identification, Behavior, Reproduction, and Distribution of Humpback Whales, 'Megaptera novaeangliae', in Hawaii

摘要

One hundred and fifty humpback whale adults, 15 subadults, and 42 calves were identified in the waters off the west coast of Maui, Hawaii in 1982 and 1983 through analysis of underwater and surface photographs. Each whale was categorized according to the pigment patterns on its flippers, flukes, throat grooves, flanks, and abdomen, the spatial-numerical pattern of its lip grooves, and the shape of its dorsal fin. The pigment patterns of these whales were found to be similar to the pigment patterns of humpback whales photographically identified in Hawaiian waters during the period 1975-1981 and to the pigment patterns of humpback whales taken through the whaling industry in waters off British Columbia and the Ryukyu Islands. During the period 1977 through 1983, fourteen females were sighted with a calf in two or more years. Three females had a one year reproductive interval producing calves in two successive years. The sex ratio of calves was 47.1% females, and 52.9% males. The sex of 39 escorts and 9 singers was determined. All were males. A decrease in the percentage of mothers and calves sighted in nearshore waters off the west coast of Maui, Hawaii has occurred since the period 1977-1979. Increasing human activities including direct interactions between whales and vessels, increased usage of specific areas by boaters and concessionaires, increased land runoff, and the occurrence of changing water quality and pollution could be significant factors contributing to the change in distribution of mothers and calves.