SOUTH GEORGIA — Roughly 50 years ago, whaling practices nearly rendered the Antarctic blue whale extinct. Now, British researchers are happily reporting this critically endangered species have made a triumphant return to South Georgia. That’s not the southern U.S. state however, but an island close to the continent of Antarctica.
Additionally, the new study finds humpback whales also seem to be returning to that area.
Commercial whaling has been outlawed since the 1960s. Since then, researchers have gathered 30 years’ worth of sightings, photographs, and underwater sound recordings to come to their conclusions.
Back in the early 20th century, blue whales made regular appearances off the coast of South Georgia. Unfortunately, it’s estimated that between 1904 and 1971 industrial whaling killed off 42,698 blue whales. Most of those deaths are believed to have taken place before the 1930s.
In the 60s and 70s, these whales essentially disappeared from the area. Between 1998 and 2018, a blue whale was spotted just once by dedicated whale surveys on ships near South Georgia.
After 2018 however, this story is beginning to change. In 2020 alone, surveyors reported 58 blue whale sightings and many other acoustic detections.
“The continued absence of blue whales at South Georgia has been seen as an iconic example of a population that was locally exploited beyond the point where it could recover,” says lead author Susannah Calderan of the Scottish Association for Marine Science (SAMS) in a press release. “But over the past few years we’ve been working at South Georgia, we have become quite optimistic about the numbers of blue whales seen and heard around the island, which hadn’t been happening until very recently. This year was particularly exciting, with more blue whale sightings than we ever could have hoped for.”
Keeping an ear out for blue whales
Besides just using their eyes, researchers also searched for the whales via listening devices capable of detecting the loud, low frequency calls of whales across vast distances and poor weather. Study authors also enjoyed access to all reported whale sightings in the South Georgia Museum made by mariners and tourists.
In total, 41 distinct blue whales have been photographed near South Georgia between 2011 and 2020.
“We don’t quite know why it has taken the blue whales so long to come back. It may be that so many of them were killed at South Georgia that there was a loss of cultural memory in the population that the area was a foraging ground, and that it is only now being rediscovered.” Calerdan adds.
“This is an exciting discovery and a really positive step forward for conservation of the Antarctic blue whale,” notes study co-author and whale ecologist Dr. Jennifer Jackson of the British Antarctic Survey. “With South Georgia waters designated as a Marine Protected Area by the Government of South Georgia and the South Sandwich Islands, we hope that these increased numbers of blue whales are a sign of things to come and that our research can continue to contribute to effective management of the area.”
The study is published in Endangered Species Research.