Up to 150 southern fin whales have been filmed feeding together in an “exciting” spectacle in Antarctica, which scientists have hailed as a sign of hope for the world’s second largest animal.
The ocean liners are second only to blue whales in length, with slender bodies that help them glide through the water at high speeds.
However, they could not escape industrial whaling and were slaughtered to near extinction in the 20th century as hunters systematically crushed whale populations around the world.
“They were reduced to 1 or 2 percent of their original population size,” said Helena Herr of the University of Hamburg, lead author of the study, published in the journal Scientific Reports. “We’re talking about a few thousand animals left for the entire southern hemisphere.”
While scientists say southern fin whale numbers have slowly recovered since a 1976 whaling ban, these mysterious animals have been spotted few in large groups at their historic feeding grounds.
But in scenes Herr described as “one of nature’s greatest events,” researchers and filmmakers were able to capture footage of up to 150 southern fin whales in Antarctica.
Drone footage captured by BBC wildlife filmmakers shows the fin whales dashing and plunging through the water, emitting large puffs of air as they surface while birds circle the sky overhead.
“The water was boiling around us because the animals were coming up all the time,” Herr said Thursday. “It was exciting to just stand there and watch it.”
During two expeditions in 2018 and 2019, researchers recorded 100 groups of fin whales ranging from small aggregations of a few individuals to eight massive aggregations of up to 150 animals.
Previously, recorded feeding groups had a maximum of about a dozen whales.
Using data from their surveys, the authors estimate that there may be nearly 8,000 fin whales in Antarctica.
Fin whales can live to around 70 or 80 years when left alone and only have one calf at a time, so population recovery is a slow process, Herr said.
She said the increasing number of southern fin whales is an encouraging sign that conservation efforts may be working, although she noted other threats, including being run over by boats.
The International Union for Conservation of Nature now lists fin whales as “vulnerable” and estimates the world population at 100,000, most of them in the northern hemisphere.
More whales could also bode well for the health of the oceans in general – and even for efforts to combat climate change.
Whales feed on iron-rich krill, but they also defecate into surface waters, returning nutrients to the ocean that fuel the growth of tiny phytoplankton, the foundation of the marine food web. Like plants on land, phytoplankton use photosynthesis, using the sun’s rays to convert carbon dioxide into energy and oxygen.
They are “ecosystem engineers,” says Herr, who accidentally discovered a large group of whales for the first time in 2013 during a research mission to study Antarctic minke whales.
She is now planning more missions to investigate the enduring mystery of these ocean giants – where they breed. “We don’t know where they’re going,” Herr said, adding that much more is known about fin whales in the northern hemisphere.
The animals can grow to 27 m (88 ft), although Herr said they were now tending to average 22 m, especially after whaling, which targeted the largest creatures.
In total, around 700,000 individual fin whales were killed for the oil in their body fat in the 20th century.