Evidence of humpback whale calving in south-west Western Australia

Abstract

An understanding of the spatial and temporal range of marine mammals, and identification of habitats that support critical behaviours is fundamental for effective species management and conservation. The humpback whale (Megaptera novaeangliae), while considered to be recovered in Australian waters, is subject to increasing levels of anthropogenic pressure across its migratory range. Historically, the Western Australian (WA) population has been known to calf in the north-west of WA in the Kimberley region (15–18° S), with recent records of calving extending as far south as Exmouth, Western Australia (21–22° S). This paper presents recent evidence of humpback whale calves being born over 1500 km further south in southwest WA (33–34° S), along their northern migratory route, including live sightings of neonates, and strandings of deceased neonate calves. The presence of neonates outside of known calving grounds presents challenges for species conservation and management with effective mitigation and management of anthropogenic pressures contingent on a contemporary understanding of species presence and behaviour. Further, there is considerable concern for the viability of calves this far south on their migratory route where water temperatures are cooler and sheltered areas for resting are more limited.