Mother Nature Network is reporting that a team of scientists led by the British Antarctic Survey (BAS) counted 55 Antarctic blue whales during their 2020 expedition to the sub-Antarctic island of South Georgia — a number they called “unprecedented.” In a previous BAS survey in 2018, only one Antarctic blue whale had been sighted.

In addition to Antarctic blue whales, the team recorded 790 humpback whales during the 21-day survey and estimated that there are now more than 20,000 of them feeding off the island seasonally.

During the period of factory-ship whaling, Antarctic blue whales were hunted to near extinction. From an estimated 239,000 whales in the 1920s, their numbers dropped to a low of roughly 360 in the early 1970s. Since the whaling moratorium of 1982, the Antarctic blue whales have grown in number at an estimated rate of 7% per year.  Recent data suggest that there may now be as many as 10,000 Antarctica blue whales.

As we posted in 2014, the California blue whale population has rebounded so that today it is approximately 97% of pre-whaling levels. While the rebound is good news, in absolute terms, it represents a relatively small group of whales. There are currently around 2,500 California blue whales.

According to the National Oceanic and Atmospheric Administration (NOAA), with whaling outlawed, the main threats to blue whales today are vessel strikes and entanglements in fishing gear.

The blue whale, which can grow to a length of almost 100′ and weigh over 170 tonnes, is the largest animal known to have ever existed.

Thanks to Alaric Bond for contributing to this post.