@article{Best_Brandão_Butterworth_2020, title={Demographic parameters of southern right whales off South Africa}, url={https://journal.iwc.int/index.php/jcrm/article/view/296}, DOI={10.47536/jcrm.vi.296}, abstractNote={<p>Aerial counts of right whale cow-calf pairs on the south coast of South Africa between 1971 and 1998 indicate an annual instantaneous<br>population increase rate of 0.068 per year (SE = 0.004) over this period. Annual photographic surveys since 1979 have resulted in 901<br>resightings of 550 individual cows. Observed calving intervals ranged from 2-15 years, with a principal mode at 3 years and secondary<br>modes at 6, 9 and 12 years, but these make no allowance for missed calvings. Using the model of Payne et al. (1990), a maximum calving<br>interval of 5 years produces the best fit to the data giving a mean calving interval of 3.12 years (95% confidence interval: 3.07, 3.17). The<br>same model produces an estimate for adult female survival rate of 0.983 (95% CI: 0.972, 0.994). The Payne et al. (1990) model is extended<br>to incorporate information on the observed ages of first reproduction of grey-blazed calves, which are known to be female. This allows the<br>estimation of age at first parturition (median 7.88 years 95% CI 7.17, 9.29). Updates of estimates and confidence intervals for the other<br>demographic parameters are: adult female survival rate 0.986 (0.976, 0.999); first year survival rate 0.913 (0.601, 0.994) and instantaneous<br>population increase rate 0.071 (0.059, 0.082). These biological parameter estimates are shown to be compatible with the observed increase<br>rate of the population without the need to postulate immigration.</p>}, journal={J. Cetacean Res. Manage.}, author={Best, Peter B. and Brandão, Anabela and Butterworth, Doug S.}, year={2020}, month={Oct.}, pages={161–169} }