Spatial and temporal habitat use of humpback whales (Megaptera novaeangliae) in relation to vessel traffic in the Gold Coast Bay, Australia

Context Humpback whales utilise coastal habitats for breeding, resting and migration where, at low latitudes, they are often exposed to vessel traffic. The Gold Coast bay (GCB) in south-eastern Queensland, Australia, is utilised by humpback whale mother–calf pairs to rest. Aims Identify core habitats of pods with and without calves and interception by vessel traffic in the GCB. Method In total, 4319 whale-sighting records from citizen science-collected data on board whale-watching vessels between 2011 and 2020 were used in this analysis. MaxEnt models were generated to determine species distribution of pods with and without calves. The distribution model was compared with automatic identification system-fitted vessel traffic available from the Australian Maritime Safety Authority over the same time to infer potential vessel impact on these sensitive cohorts. Key results Habitat use of pods with calves was focused on shallower areas close to shore and overlapped with the core habitat of pods without calves 5 km into the bay. Vessels intercepted up to 80% of the core habitat. Conclusion Vessel traffic poses a potential threat to humpback whale mother–calf pairs. Implications An assessment of all vessels leaving the seaway should be considered for the GCB and whale caution zones for vessel traffic.