Evidence for a widely expanded humpback whale calving range along the Western Australian coast

• Published in: Marine Mammal Science
• Main Authors: Irvine, LG, Thums, M, Hanson, CE, McMahon, CR, Hindell, MA
• Format: Article in Journal/Newspaper
• Language: English
• Published: Soc Marine Mammalogy 2017
• Subjects: Biological Sciences; Ecology; Population Ecology; Broome; West Cape; Humpback Whale; Megaptera novaeangliae
• Online Access: https://doi.org/10.1111/mms.12456; http://ecite.utas.edu.au/125805

The recognized calving grounds of humpback whales ( Megaptera novaeangliae ) that breed along the Western Australian coast (Breeding Stock D) extend along the Kimberley coast between Camden Sound and Broome (1518S). However, there are reports of neonates further south, suggesting that the calving areas may be poorly defined. During aerial photogrammetric research in 2013 and 2015, we sighted large numbers of humpback whale calves along North West Cape (2147′2243′S). We estimated the minimum relative calf abundance to be 463603 in 2013 and 557725 in 2015. We categorized the calves as either neonate or post neonate according to their color and size. The majority of calves sighted in both years (85% in 2013; 94% in 2015) were neonates. Our observations indicate that a minimum of approximately 20% (17.1.3%) of the expected number of calves of this population are born near, or south of, North West Cape. We thus demonstrate that the calving grounds for the Breeding Stock D population extend south from Camden Sound in the Kimberley (15S) to at least North West Cape (2243′S), 1,000km southwest of the currently recognized calving area.