Mise à jour sur les quatre baleines franches australes marquées
There have been some remarkable developments from the four southern right whales that were tagged in Walker Bay, South Africa, in October 2021. The whales were tagged with the aim of improving our understanding of the migratory and foraging behaviour of southern right whales that use the coast of South Africa as a calving ground. Two females in particular have completed very long treks, one to the Patagonian shelf, a feat that has thus far been undocumented, and another to the South Sandwich Islands. Both these journeys are more than 10,000 km long and reveal migratory routes which were previously not known for southern right whales which calve in South Africa. These new migratory routes could be a sign of a changing Southern Ocean whereby southern right whales are responding to changes in the distribution of prey driven by environmental alterations. They also reveal a connection with the Argentinian population, which was previously indicated only from DNA analyses. This work demonstrates that the two populations mix on the main feeding grounds used by Argentinian southern right whales. The other two whales have been feeding in foraging grounds which are thought to be more frequently used by South African southern right whales. One was foraging for an extended period in waters surrounding Crozet Island but the tag stopped transmitting after 135 days. The other was last detected near Bouvet Island. There is still a great deal we do not know about the offshore migratory and foraging behaviour of southern right whales that use South Africa as a calving ground, and this data Is crucial to improving our understanding.