Southern right whale (<scp> Eubalaena australis </scp>) population demographics at major calving ground Head of Bight, South Australia, 1991–2016

• Published in: Aquatic Conservation: Marine and Freshwater Ecosystems
• Main Authors: Charlton, Claire, McCauley, Robert D., Brownell, Robert L., Ward, Rhianne, Bannister, John L., Salgado Kent, Chandra, Burnell, Stephen
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2022
• Subjects: Nature and Landscape Conservation; Ecology; Aquatic Science; Southern Right Whale
• Online Access: http://dx.doi.org/10.1002/aqc.3771; https://onlinelibrary.wiley.com/doi/pdf/10.1002/aqc.3771; https://onlinelibrary.wiley.com/doi/full-xml/10.1002/aqc.3771

Abstract Demographic parameters were estimated for southern right whales (SRWs), Eubalaena australis , using photo‐identification (photo‐ID) and count data collected during annual cliff‐based surveys at the Head of the Great Australian Bight (HoB), South Australia between 1991 and 2016. Photo‐ID and count data were contributed from the annual aerial surveys of the south‐western population in Australia (1993–2016). The HoB photo‐ID database included 1,186 non‐calf individuals, with 459 reproductive females. HoB is an open population and represents a relative proportion (0.48–0.21) of the overall south‐western population, which is decreasing with population growth. No change was detected in the growth rate at HoB over time (1992–2016) and there was no significant difference when compared to the overall south‐western population. The estimated mean rate of increase for all SRW was 3.2% (± 1.3) per annum and for females with a calf was 4.6% (± 1.7) per annum at HoB, compared to 5.5% (95% confidence interval (CI) 3.78, 7.36) and 6.01% (95% CI, 3.78, 7.36), respectively for the south‐western population during the same period. The apparent mean calving interval was 3.3 years (SD = 0.78, ± 0.14, 95% CI; 1996–2016), and a significant increase to 4 years was observed since 2015. The apparent mean age at first parturition was 9.0 years. The minimum estimated age of the oldest whale was 50 and oldest lactating female 41 years old. The SRW demographic data provides information for monitoring recovery, population status, species conservation management and global comparative studies. There is a need to understand fluctuations in calving intervals, threats to the population and implications for species recovery.