This record provides an overview of the NESP Marine and Coastal Hub project "Aerial survey of the Southern Right Whale ‘western’ sub-population off southern Australia". For specific data outputs from this project, please see child records associated with this metadata.
Southern right whales are listed as Endangered under the EPBC Act and are a species of national conservation significance. Monitoring of their recovery is guided by the Southern Right Whale Conservation Management Plan, which aims to improve the population’s conservation status through regular assessment of population size, calving intervals, and spatial trends.
This project continued the long-term aerial survey program of southern right whales along the southern Australian coast, spanning from Perth (WA) to Ceduna (SA). Annual surveys have been conducted since 1993, providing a continuous long-term dataset for the 'western' population and supporting national assessments of connectivity with the smaller ‘eastern’ population. The surveys contribute essential data on population trends, calving rates, and movements of individuals.
The August 2022 aerial survey ensured an uninterrupted time series in the long-term population trend data. This is particularly important given the species' non-annual breeding cycle (typically every three years). Annual surveys are essential to maintain an acceptable level of precision in estimating population trends and key life history parameters. A total of 526 whales were recorded, including 247 cow–calf pairs, 31 unaccompanied adults and one yearling. Based on long-term models, this equated to a population estimate of approximately 2,675 individuals, with an average annual growth rate of ~5.3%.
While this represents a continued population growth, results suggest a possible slowing in the rate of growth over the past 13 years (from 7.5% in 2009). The 2022 survey also recorded the lowest number of unaccompanied animals in the entire time series, extending a five-year trend of low sightings in this group. Continued monitoring of the population is needed to assess whether these changes represent longer-term shifts in population dynamics and calving intervals, and to inform adaptive management for this long-lived, slow-recovering species.
Outputs
• Estimate of relative abundance and population trend compared to long-term aerial survey sightings [dataset]
• Individual whale photo-identification data - 2021-22 season [imagery - published to ARWPIC]
• Final technical report detailing overall numbers of southern right whales observed within the survey region, their gender (and life stage where possible) and spatial distribution of individuals [written]
