Technical report

File type: PDF

Smith JN, Double M and Kelly N (2024) Relative abundance of the ‘western’ population of southern right whales (Eubalaena australis) from an aerial survey off southern Australia: Final Report on 2023 survey. Report to the National Environmental Science Program. Murdoch University (Lead organisation).

Overview

This final technical report provides the results from the 2023 aerial survey of the ‘western’ population of southern right whales in Australian waters, which contributes to the long-term population trend data used to evaluate the recovery of the species. The results directly inform State and Commonwealth government management of this Endangered species, specifically providing a status on the abundance and population trend of the ‘western’ population to directly inform the Southern Right Whale Recovery Plan. There continues to be considerable inter-annual variation in whale numbers that makes it difficult to detect consistent and reliable changes in abundance from one year to the next, and while there is an increasing population trend in abundance there is also evidence of a potential slowing down in the rate of increase of female-calf pairs. Consequently, it is difficult to identify immediate threats to the population and reliably understand potential impacts from anthropogenic activities on species recovery. Importantly, there are several natural and anthropogenic threats that affect southern right whales that are likely to interact, and their cumulative effects may severely affect recovery of the species. Continued annual population aerial surveys to inform long-term population trend data from the western population will be the best approach to assess species recovery and any potential slowing of the population growth rate.

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