The largest animal ever to have lived on Earth appears to be making a comeback.
Record numbers of the Antarctic blue whale have been tallied off South Georgia Island in the South Atlantic, spurring hopes that this species will join the recovery of humpbacks and other whales that were once decimated by commercial whaling.
Whaling — for science
For nearly a month during the current sub-Antarctic summer, the British Antarctic Survey’s South Georgia Whale Project circled South Georgia Island in the research vessel R/V Braveheart.
They were hoping to document southern right whales, but were mostly disappointed.
It appeared that the right whales were feeding farther north this year, off the Argentinian mainland.
But humpbacks were found in abundance—790, to be precise.
And what really captured attention were 55 blue whales.
A single blue whale (Balaenoptera musculus) can be 165 tons and over 100 feet long.
Historically, a major Antarctic population of blue whales summered by the tens of thousands off South Georgia, feeding on the currents carrying krill north from the Antarctic Peninsula.
Then, a century ago, commercial steam-powered harpoon whaling moved in.
Commercial whaling ban
In the coming decades, whalers killed at least 42,000 individual blue whales, and the population was reduced to the low hundreds by the 1960s when a ban went into effect.
After that, blue whale sightings off South Georgia Island plummeted to less than five total over the past 60 years — until now.
Researchers and conservationists hope that the commercial whaling ban will see the same results with blue whales and southern right whales that it has with humpbacks and other species.
Some 20,000 humpbacks feed around South Georgia now, and it is believed that their numbers have largely rebounded from pre-1960 lows.
The current expedition brought scientists from five countries to learn as much about whales and their prey as possible.
3D acoustics
They used underwater microphones to record whale songs — and caught sight of the big blues breaching the ocean’s surface.
Using drones, the team was also able to get overhead images and collected water from blowholes.
With “biopsy darts,” the scientists took blue whale skin samples that will provide valuable data on genetic identity and diversity, as well as diet.
The scientists also used an “echosounder,” which uses acoustics to create a three-dimensional image of whales’ environment to better understand what the whales are feeding on.
While the Earth’s largest — and perhaps its most charismatic — megafauna appears to be coming back from the brink of extinction, ecologist Jennifer Jackson, the team’s leader, told BBC News that there are no guarantees.
Blue whales will need ongoing protection, she said, and scientists will need to continue monitoring them to determine whether this “unprecedented number of blue whale sightings” is a long-term trend.
Sources: BBC News, British Antarctic Survey: “South Georgia whale expedition in full swing,” “Blue whale comeback at South Georgia!”