Intersessional working group report: Multi-ocean assessment of southern right whale demographic parameters and environmental correlates
Doug Butterworth, Justin Cooke, Claire Charlton, Els Vermeulen, Andrea Ross-Gillespie, Anabela Brand?o, et al.
The work of the Intersessional Working Group (WG) ?Multi-ocean assessment of southern right whale (SRW) demographic parameters and environmental correlates?? aims to compare SRW population demographics across the main southern hemisphere (SH) wintering grounds. This is to be achieved by applying a common demographic model to the populations in each region: Southwest (SW) Atlantic (Argentina/Brazil), Southeast (SE) Atlantic (South Africa), Australia and New Zealand, in order eventually to test hypotheses for the relationships between reproductive success and environmental variables. The project is an integral component of the International Whaling Commission Southern Ocean Research Program (IWC-SORP) Theme 6, ?The right sentinel for climate change: linking foraging ground variability to population recovery in the SRW?. The IWC-SORP funding proposal related to this WG, submitted in January 2020 (SC/68b/O01), was successful.
Key progress made between April 2021 and March 2022 includes:
The Southern Right Whale Consortium was established to facilitate multi-ocean collaboration and to develop data quality control standards ? the related Memorandum of Understanding has initially been signed by 11 southern right whale researchers, and remains open to all those interested.
At the time of the last report, the version of the common model applied to the SW Atlantic data incorporated an additional ?unsuccessful mother? component. This explicitly modelled the number of females experiencing late abortions or early calf deaths, as this was found to be important for fitting to the data for the region. This component was not present in the version of the model applied to the South African data. Since then, this component has been included in the formal specification of the common model. The coding for this inclusion is almost complete, with model-fitting to commence soon. The model will first be fit to the South African data, then to the other available data sets.
A global desk-top assessment of southern right whale sightings South of 40?S was completed by honours student Cuyler van Jaarsveld (University of Pretoria). Data were collected from multiple sources and used to produce maps in order to visualize where and when SRWs were sighted. A total of 357 sightings data points were collected from 13 separate sources, including SOWER cruises, CCAMLR, Happywhale, PROANTAR, ObsInt, IWC reports and the South Georgia Heritage Trust Database. A full report can be seen at SC/68d/SHxx