Scientists have documented an “astonishing” number of blue whales off the sub-Antarctic island of South Georgia — a region where they had been almost wiped out by commercial whaling in the early 20th century, the BBC reported. The international team of researchers counted 55 blue whales during a 25-day survey period. In contrast, a 2018 survey sighted just one blue whale.
“To think that in a period of 40 or 50 years, I only had records for two sightings of blue whales around South Georgia,” Trevor Branch, a cetacean specialist at the University of Washington who was on the survey team, told the BBC. “Since 2007, there have been maybe a couple more isolated sightings. So to go from basically nothing to 55 in one year is astonishing.”
The scientists tracked whales in near-shore waters off South Georgia both visually and acoustically. They also retrieved skin and breath samples to study the health of the whales.
Sub-Antarctic blue whales were once one of the biggest blue whale populations in the world, with an estimated 239,000 individuals before the onset of commercial whaling from South Georgia in 1904. The industry peaked in 1931, with 30,000 blue whales killed in a single year, according to the International Union for Conservation of Nature. A 1998 estimate put the whales’ sub-Antarctic population at just 2,280 individuals. For years, scientists spotted just one or two blue whales during annual surveys.
“We know that 100 years ago, South Georgia was a good place for blue whales and now, after decades of protection, it seems the territory’s waters are a good place for them once again,” Jennifer Jackson, the survey team leader and a whale ecologist at the British Antarctic Survey, told the BBC.