NESP MaC Project 1.26 - Relative abundance of the ‘western’ population of southern right whales from an aerial survey off southern Australia, 2021-2022 (Murdoch Uni)

This record provides an overview of the NESP Marine and Coastal Hub bridging study - "A photo-identification study of southern right whales to update aggregation area classification in the southwest of Australia". For specific data outputs from this project, please see child records associated with this metadata.

The southern right whale (Eubalaena australis) is listed as Endangered under the Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act) 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 outlines the current status of, and threats to, the southern right whale in Australian waters and prioritises recovery actions during this period. The long-term vision for the recovery of this species in Australian waters is to increase the population size to a level that the conservation status improves, and the species no longer qualifies for listing as threatened under any of the EPBC Act listing criteria. 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 (W.A.) to Ceduna (S.A.) since 1993, as part of a long-term program to monitor the recovery, and inform the Conservation Management Plan (2011-2021), for this Endangered species. In Australia’s south-east, there has been little sign of recovery in southern right whale numbers following intense commercial whaling. A working hypothesis assumes separation between the ‘western’ and ‘eastern’ populations, largely due to loss of ‘cultural memory’ of whales migrating to the eastern range breeding areas. Given the relative paucity of animals that visit the southern Australian coast in areas other than south-west Australia, the western population is considered to represent the majority of the ‘Australian’ southern right whale population. The count data from these aerial surveys provide data on population trend and estimates of population size for the ‘western’ population, and hence the majority of the Australian southern right whales. Associated photo-identification data provide life history information (such as calving intervals) and connectivity between the ‘western’ and ‘eastern’ populations and contribute to the national southern right whale photo-id database: the Australasian Right Whale Photo-Identification Catalogue (ARWPIC).

The 2020 aerial survey program recorded substantially lower numbers of whales than in the previous 13 years, and the lowest number of non-calving whales since the program started. This project conducted new aerial surveying in August 2021 to provide a relative estimate of annual population size for determining longer term population trends and contribute to determining if 2020 was an anomalous year or an indicator of some longer-term change to recent recovery rates and the female breeding cycle.

Outputs
• Aerial whale survey data (counts by size class, number, and location) - 2021-22 season [dataset]
• Individual whale photo-identification data - 2021-22 season [imagery - published to ARWPIC]
• Final Project Report including a short summary of recommendations for policy makers of key findings [written]

Tags: National Environmental Science Program (NESP) Marine and Coastal Hub, aerial survey, endangered, photo-identification, southern right whale, threatened species
Organization: Australian Ocean Data Network