Assessment of humpback whale swimming speeds in two eastern Australian bays

Context Humpback whales (Megaptera novaeangliae) are capital breeders, travelling several thousand kilometres between their breeding and feeding sites annually. Along the migration route, humpback whales utilise locations such as Hervey Bay and the Gold Coast bay for resting. Methods Here we used sightings data from 2066 boat-based surveys spanning 11 years. Aims To compare and analyse the sighting data and evaluate the swimming speed in Hervey Bay and the Gold Coast bay. Key results During southward migration, swimming speeds observed in Hervey Bay and the Gold Coast bay for both pods with and without calves were slower than are migration speeds reported in literature for each pod type. Whales swam faster in the Gold Coast bay (mean = 4.14 km h−1) than Hervey Bay (mean = 3.32 km h−1); however, the effect of location on swimming speed was small. In Hervey Bay, swimming speeds of pods without calves were faster (mean = 3.48 km h−1) than swimming speeds of pods with calves (mean = 3.15 km h−1). Conclusions Our findings contribute to the understanding of swimming speeds in different humpback whale cohorts and their movements in nearshore environments. Implications Understanding the importance of the role of humpback whale swimming speed in nearshore environments for assessment of habitat use can help management of such areas for effective protection of humpback whales.