Migration of the Southern Right Whales | Polarjournal
The Southern Right Whales are called “Right whales” in English because they were the ‘right’ whales for whaling due to their buoyancy and low swimming speed. For more than 350 years, the population in the South Atlantic has been heavily exploited. In 2009, the global population was estimated at 13,611 animals. Photograph: wildestanimal/Shutterstock

Scientists from the British Antarctic Survey have discovered where Southern Right Whales(Eubalaena australis),which go all around the sub-Antarctic island of South Georgia in search of food, reproduce during the winter months. This knowledge of where the animals migrate from will provide protection for their recovery after years of whaling. The findings will be published this week in the Journal of Heredity.

Southern Right Whales were hunted almost to extinction after centuries of whaling. In the most comprehensive study of its kind, 30 researchers from 11 countries examined 15 skin samples of whales seeking food near the sub-Antarctic island of South Georgia and compared them to 149 samples collected from the waters around Argentina, Brazil and South Africa, where the whales mate and give birth to their calves. New samples were collected from South Georgia during an expedition led by the British Antarctic Survey in 2018 and combined with samples stored by a network of staff around the world.

Using a new genetic tool, the team discovered that most of the animals that came to South Georgia were born in South America, not South Africa. This had previously been suspected, but not confirmed. Dr Emma Carroll, from the University of Auckland, lead author of the study, said: “Genetic methods are important to link the mating areas of the whales – areas closely monitored for population recovery – to the food causes that are and will be affected by climate change. Only when we know these connections will we understand how whale populations will be able to cope in a changing world.”

A Southern Right Whale off South Georgia, the epicentre of modern whaling in the southern hemisphere with more than 170,000 animals killed. The South Georgia Right Whale Project is now tracking whales equipped with GPS transmitters to better protect them. Photo: Amy Kennedy

In collaboration with Chilean colleagues, the team also analyzed the very first DNA sample of the endangered Southern Right Whale population off Chile and Peru. They found that the Chile-Peru whale is genetically a mixture of animals born in Indo-Pacific and Atlantic waters, suggesting that the Chile-Peru region acts as a “stepping stone” to these two areas.

Whale ecologist and senior author Dr Jennifer Jackson from the British Antarctic Survey, who led the project, said: “This is an important part of the puzzle to understand the geographical reach of Souther Right Whales. Identifying the migratory relationships of recovering whale populations is critical to obtaining accurate assessments of how well whale populations are recovering and to understand how vulnerable these populations are to anthropogenic threats throughout their life cycle.” She adds that over the last 17 years, Argentina has had inexplicably high mortality rates for whale calves at the Valdéz Peninsula. Thus, much remains to be done to protect this species throughout its migratory area.

The team also tracks the movements of two South Georgian Right Whales in real time using satellite tags. A whale is already migrating towards the South American coast, providing further evidence of the migration route. Map: South Georgia Right Whale Project, British Antarctic Survey

The movements of the whales can be tracked under the following link: https://www.bas.ac.uk/project/south-georgia-right-whale-project/south-georgia-right-whale-project-whale-tracking/

Source: British Antarctic Survey

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