Species Profiles: Life Histories and Environmental Requirements of Coastal Vertebrates and Invertebrates, Pacific Ocean Region. Report 2. Humpback Whale, Megaptera Novaeangliae.

摘要

Commercial over exploitation resulted in the depletion of the North Pacific population of humpback whales. A major component of this population winters in Hawaiian waters, where reproductive activities occur. There are no apparent identifiable trends in the status of this population. This may be due to inconsistent survey effort, the imprecision of survey techniques that are unable to detect small changes, no measurable trend, or one or any combination of these factors. During the winter breeding season, humpback whales are found within the 100-fathom isobath and shallower waters around the main Hawaiian Islands. Cow-calf pairs, in particular, demonstrate an affinity for waters of less than 50 fathoms. It appears that size, depth, and substrate of shallow bank areas are important elements in the distribution of humpback whales on their wintering grounds. The sea-surface temperature in Hawaiian waters ranges from 23.2 to 24.2 C during the winter breeding season and is at the low range of water temperatures in comparison with breeding areas in other parts of the world. The major environmental impact facing humpback whales in Hawaiian waters is the loss and modification of shallow nearshore habitat to harbor, resort, and other coastal development, and the subsequent increase in human activity including vessel traffic, which may result in disturbance and displacement of humpback whales from preferred habitat. Keywords: Environmental requirements; Hawaii, Humpback whale; Life cycles. (kt)