Factors driving the variability in diving and movement behavior of migrating humpback whales (Megaptera novaeangliae): Implications for anthropogenic disturbance studies

TitleFactors driving the variability in diving and movement behavior of migrating humpback whales (Megaptera novaeangliae): Implications for anthropogenic disturbance studies
Publication TypeJournal Article
Year of Publication2017
AuthorsKavanagh, Ailbhe S., Noad Michael J., Blomberg Simon P., Goldizen Anne W., Kniest Eric, Cato Douglas H., and Dunlop Rebecca A.
JournalMarine Mammal Science
Volume33
Pagination413-439
ISBN Number1748-7692
EndNote Rec Number11895
Keywordsanthropogenic disturbance, behavior, BRAHSS, diving, environmental context, humpback whale, Megaptera novaeangliae, migration, movement, social context
Abstract

Humpback whales (Megaptera novaeangliae) undertake one of the longest migrations of any animal and while on a broad-scale this journey appears direct, on a fine-scale, behaviors associated with socializing and breeding are regularly observed. However, little is known about which social and environmental factors influence behavior during this time. Here we examined the effect of multiple factors on the movement (speed and course) and diving behavior (dive and surfacing duration) of humpback whales during migration off the eastern coast of Australia. Focal data (202 h) were collected on 94 different whale groups with simultaneous social and environmental context data. The environmental factors water depth and wind speed were found to be important predictors of dive and movement behavior, whereas social factors were less influential at this site. Groups tended to dive for longer with increased water depth but traveled more slowly in increasing wind speeds. These baseline studies are crucial when examining the effect of anthropogenic disturbance. Determining which natural factors significantly affect behavior ensures any observed behavioral changes are correctly attributed to the disturbance and are not a result of other factors. In addition, any responses observed can be put into biological context and their relative magnitude determined.