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The discovery of whale products and their many uses saw humanity hunt blue whales to near extinction in the waters surrounding the sub-Antarctic island of South Georgia. Now, 50 years on, they have returned to the region and a new study published in the journal Endangered Species Research thinks humpback whales may be following suit.
The research analyzed 30 years’ worth of sightings, recordings and photographs to investigate how the diminished population was faring following a pivotal ban on whaling in the 1960s. From 1998 to 2018, only a single blue whale was sighted by dedicated whale surveyors practicing on ships in South Georgia, but the past two years these enormous marine mammals appear to have been making a comeback.
A survey carried out in just February of 2020 recorded 58 blue whale sightings as well as an abundance of sound recordings. Blue whales emit loud, low frequency calls which can be picked up by the team’s recording equipment even across long distances and in bad weather. The sightings and recordings combined with photo evidence have enabled the researchers to identify 41 blue whales in South Georgia from 2011 to 2020, but strangely none of these matched the 517 whales in the current Antarctic blue whale photographic catalogue.
Blue whales were once abundant around South Georgia but a boom in whaling in the early 20th-century saw 42,698 of them killed from 1904 to 1971, most of which died at the hands of whalers before 1930. As a species they were pushed to near extinction, but this recent bounce back paints a hopeful future for the world’s biggest animal.
"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,” said lead author Susannah Calderan of the Scottish Association for Marine Science (SAMS) in a statement. “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."
Human activity has impacted the lives of Antarctic blue whales in many ways. Research in 2017 discovered that in response to the din created by human pursuits in the oceans, blue whales changed the frequency of their calls making them lower so that they could hear one another amid the racket. However, these resilient animals endure and this good news story joins that of Californian blue whales who were also reported to have bounced back from whaling back in 2014.
