Ecosystem modelling to quantify the impact of historical whaling on Southern Hemisphere baleen whales

• Published in: Fish and Fisheries
• Main Authors: Tulloch, Vivitskaia J. D., Plaganyi, Eva E., Matear, Richard, Brown, Christopher J., Richardson, Anthony J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley-Blackwell Publishing 2017
• Subjects: Antarctic; Baleen whale; Commercial whaling; Ecosystem model; Krill; Multispecies model; 1104 Aquatic Science; 1105 Ecology; Evolution; Behavior and Systematics; 1910 Oceanography; 2308 Management; Monitoring; Policy and Law; Indian; Antarc*; Balaenoptera musculus; Balaenoptera physalus; baleen whale; baleen whales; Euphausia superba; Megaptera novaeangliae
• Online Access: https://espace.library.uq.edu.au/view/UQ:685472

Many baleen whales were commercially harvested during the 20th century almost to extinction. Reliable assessments of how this mass depletion impacted whale populations, and projections of their recovery, are crucial but there are uncertainties regarding the status of Southern Hemisphere whale populations. We developed a Southern Hemisphere spatial "Model of Intermediate Complexity for Ecosystem Assessments" (MICE) for phytoplankton, krill (Euphausia superba) and five baleen whale species, to estimate whale population trajectories from 1890 to present. To forward project to 2100, we couple the predator-prey model to a global climate model. We used the most up to date catch records, fitted to survey data and accounted for key uncertainties. We predict Antarctic blue (Balaenoptera musculus intermedia), fin (Balaenoptera physalus) and southern right (Eubalaena australis) whales will be at less than half their pre-exploitation numbers (K) even given 100 years of future protection from whaling, because of slow growth rates. Some species have benefited greatly from cessation of harvesting, particularly humpbacks (Megaptera novaeangliae), currently at 32% of K, with full recovery predicted by 2050. We highlight spatial differences in the recovery of whale species between oceanic areas, with current estimates of Atlantic/Indian area blue (1,890