Occurring along Peninsula Valdés in Argentina--one of the most important calving and nursing grounds for the species, according to Dr Howard Rosenbaum of the Wildlife Conservation Society--potential explanations for the die-off include: Biotoxins, disease, environmental factors at their nursing grounds, and variations in prey availability in their feeding grounds.Raising a call to research, Dr Marcela Uhart, also of WCS, said,
We need to critically examine possible causes for this increase in calf mortality so we can begin to explore possible solutions. Finding the cause may require an expansion of monitoring activities to include the vast feeding groups for the species.
How vast? Try entirely around Antarctica.
Southern Right Whales Endangered, But Populations Increasing
Though still listed as endangered by the IUCN, with an estimated population over about 12,000 worldwide, the southern right whale is generally considered a conservation success story. Populations have rebounded since hunting of them was prohibited in 1937, growing about 7% per year since the 1970s. Northern right whale populations have not fared so well, with populations remaining low.