Endangered blue whale We have returned to the waters near the remote islands of South Georgia near the Antarctic Continent, the largest animal ever known to exist. It was almost 100 years after the giant mammals were almost extinct due to industrial whaling.
According to researchers, a recent survey of the waters around the subantarctic island, which was the center of industrial whaling until the ban in the 1960s, found only one whale between 1998 and 2018. Ten blue whales were recorded.
“In the last few years, there have been signs that more blue whales may return to South Georgia,” marine mammal ecologist Susanna Calderan told Live Science. “But I was very positively surprised to meet quite a few people this year.”
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Calderan, a researcher at the Scottish Marine Science Society (SAMS), is the lead author of a study on the resurrection of blue whales near South Georgia, published in a journal Thursday (November 19). Research on endangered species..
In January and February of this year, she boarded the New Zealand research vessel Braveheart and took part in an expedition to the waters around South Georgia led by British Antarctic Survey whale biologist Jen Jackson, who co-authored the new study.
Scientists were surprised to find numerous blue whales in the once eradicated area — she said — 38 blue whales appeared on the surface in a few weeks, with a total of 58 whales and a “sonobuoy”. Many acoustic detections have been made. Equipped to monitor underwater whale songs.
South Georgia is the largest island in the distant South Atlantic archipelago, known as South Georgia and the South Sandwich Islands.
The island is about 2,500 miles (4,000 km) from the Antarctic coast, but within the Antarctic Convergence Line. This is the hydrological boundary between the surrounding cold water. Antarctica And the warmer waters north.
Now only a few months live every summer, but South Georgia History of Antarctic exploration..
At the beginning of the 20th century, it became the center of industrial whaling — virtually “Ground Zero” For whaling, first for humpback whales and later for blue whales.
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According to a Calderan study, more than 42,000 blue whales were killed around South Georgia between 1904 and 1971, most of them by the mid-1930s. “In the early 1900s, the South Georgia waters were flooded with blue whales. In just over 30 years, they were almost gone,” the researchers write.
“It was a matter of luck that they weren’t completely wiped out,” Calderan said. “By the end of whaling, the blue whale population was estimated to be 0.15% of pre-whaling levels. They would not have been able to stay longer.”
Although blue whale populations have increased in other parts of Antarctica in recent decades, she said, spectacular sea dwellers were rarely found in the waters around South Georgia until recent expeditions.
Resurrection of whales
As a result of the near extinction of blue whales around South Georgia in the early 20th century, a “cultural memory” of the abundance of Antarctic krill, a small swimming crustacean found in large herds of the Antarctic Ocean, is available. It may have been lost. Knowledge of the habitat of blue whales can be passed on from mother whales to calves. “Probably there was a cultural memory that the animals that came to South Georgia were lost because they were wiped out,” Calderan said. “They couldn’t convey their knowledge of the feeding grounds because no one was left.”
However, evidence from recent research suggests that at least some blue whales have rediscovered the abundance of krill in South Georgia.
“I think you’re likely to see evidence of site fidelity to a particular feeding ground. This explains why. [blue whale] Numbers began to recover in the wider Antarctica, but it took longer to recover in South Georgia, “said Calderan.
The increase in blue whales around South Georgia was found by a BAS survey. Humpback whale It is also increasing in the region — like the blue whale, humpback whales have been almost extinct by industrial whaling.
“That’s a good sign,” Calderan said. “This is an area that has been particularly hit by whaling, and it’s really encouraging to see whales again.”
Originally published in Live Science.
The Antarctic blue whale returns to South Georgia a century after it was almost wiped out.
Source link The Antarctic blue whale returns to South Georgia a century after it was almost wiped out.