Preliminary results for a photo-identification-based assessment of southern right whales in South African waters

Abstract

This working paper presents preliminary results of a photo-id based assessment of southern right whales in South African waters using the three-mature-stages (receptive, calving, resting) model of Cooke et al. (2003). The application of the approach is near-identical to that of Cooke et al. (2003), except that here the starting population is not assumed to reflect a steady age-structure corresponding to the Leslie matrix model describing the population dynamics. The photo-id data for grey-blazed female calves, which are identifiable when giving birth themselves, are used to link the dynamics of the mature females with the output of their reproduction by allowing for estimation of parameters for first-year mortality and the maturity ogive.