The endangered blue whales – one of the largest animals known to exist – have returned to the waters near the island of South Georgia, almost a century after the blue whale was made extinct due to industrial whaling. The industrial whaling in the waters around the Sub-Antarctic island was banned in the 1960s.
Recent research published in the Endangered Species Research recorded dozens of blue whales near the remote island where a single blue whale had been noticed between 1998 and 2018. Susannah Calderan, a marine mammal ecologist and lead author of the research, said that they have had indications in the previous years that there could be more blue whales coming back to South Georgia.
In February this year, Susannah went on an expedition with Jen Jackson, a whale biologist and co-author of the research. They were surprised to notice dozens of blue whales in an area where they were eradicated – 38 sightings over a few weeks, including 58 blue whales, and many acoustic recordings.
According to Susannah`s study, over 42.000 blue whales were killed between 1904 and 1971 in South Georgia. In the 1900s, South Georgia waters were crowded hoarded with blue whales, but within 30 years they were all gone. Even though populations of blue whales have been rising in some parts of the Antarctic, they were almost unseen in the waters near South Georgia until the exhibition.
Susannah said that the extinction of blue whales in the waters near South Georgia in the 20th century could have resulted in the loss of their cultural memory of Antarctic krill, small crustaceans found in large swarms in the Southern Ocean, and the only food of whales.
However, a recent study showed that some blue whales have found out the abundance of krill in South Georgia.
The rise in blue whales around South Georgia came after the research, suggesting that the population of humpback whales had also increased. Like blue whales, humpback whales were also driven to extinction caused by industrial whaling.