Aerial survey of the Southern Right Whale ‘western’ sub-population off southern Australia

PROJECT 2.7

The Southern Right Whale is listed as Endangered under the Environmental Protection and Biodiversity Conservation Act 1999 and is subject to conservation listings in five Australian states due to severe population declines caused by historical whaling.

The Southern Right Whale Conservation Management Plan 2011–2021 provides a framework for collaborative efforts between countries and other stakeholders to protect and rebuild populations, as required under Australia’s membership of the International Whaling Commission. The plan must be periodically updated to reflect new knowledge and prioritise the research needed to monitor population recovery and predict the impacts of threats such as climate change.

Aerial surveys of Southern Right Whales have been conducted across the southern Australian coast from Perth, WA to Ceduna, SA since 1993, as part of a long-term program to monitor their recovery. The surveys data provide a long-term population trend for this ‘western’ population, and provide an understanding of connectivity with the ‘eastern’ population as part of a national population assessment. The NESP Marine Biodiversity Hub (a predecessor to the NESP Marine and Coastal Hub) funded the aerial surveys in 2015–2020 and the Marine and Coastal Hub funded the survey in 2021. (See Project 1.26.)

The 2022 survey will ensure an uninterrupted time series in the long-term population trend data for this Endangered species. This is particularly important given the non-annual breeding cycle (typically every three years), such that annual surveys are essential to maintain an acceptable level of precision in estimating population trends and key life history parameters (calving intervals) to track the recovery of the species. Continued monitoring of the population is needed to evaluate whether there is a longer term and continuous change (in population size and calving intervals) in the population as indicated by recent sightings and population trend data.

Aerial survey between Cape Leeuwin and Ceduna

An aerial survey utilising established protocols developed and used in previous surveys (since 1993) of the south-west Australian region will be undertaken during August 2022 when seasonal whale numbers are estimated to be highest across the region. The surveys will be conducted using a high wing, single engine aircraft crewed by a pilot/observer, photographer/observer and data scribe along the southern coast of Australia (to 1nm offshore) between Cape Leeuwin (Western Australia) and Ceduna (South Australia) at a survey altitude of 1000 feet. Dependent on weather, it is expected that the return survey time will be ~5–6 days to fly the survey region and back (based on previous surveys).

Photo-identification images of encountered whales are taken and life history data is obtained by matching whales to the Australasian Right Whale Photo Identification Catalogue (ARWPIC) dataset managed by the Australian Antarctic Division Data Centre of the Department of Climate Change, Energy, the Environment and Water.

Whale numbers recorded by the survey will provide a relative estimate of annual population size, and when combined with the longer term dataset, a relative trend of the ‘western’ population. Photographs will be processed and uploaded to ARWPIC and then coded and matched against the catalogue to identify potential resights of individuals. The data from the survey will be an essential contribution to a larger dataset aimed at determining absolute abundance, spatial connectivity, changes in life history parameters across the population and environmental influences on these, however it is beyond the scope of this project to carry out such analyses.

The findings of this project will contribute to informing the Australian Government’s Southern Right Whale Conservation Management Plan 2011–2021, and in particular provide further information on population trends and the extent to which 2021 might be considered an anomalous year. These outputs will be important for identifying priority areas of research for the species, in light of a review of the management planand development of future management plans.

The data resulting from this project will also contribute to the International Whaling Commission Southern Ocean Research Partnership (IWC-SORP) funded project “Multi-ocean assessment of southern right whale demographic parameters and environmental correlates” through the Australian Southern Right Whale Consortium. This is a collaboration between countries from the South West Atlantic (Brazil/Argentina), South East Atlantic (South Africa), Australia and New Zealand, with the aim to compare population demographics across the main Southern Hemisphere wintering grounds.

Project location

Across the southern Australian coast from Perth, WA, to Ceduna, SA.

Related projects