For the first time since the ban on catching fin whales, a research team in the Antarctic has discovered larger populations of the more than 20 meter long animals. During two expeditions near the Antarctic Peninsula in 2018 and 2019, the team led by biologists Helena Herr from the University of Hamburg and Bettina Meyer from the Alfred Wegener Institute in Bremerhaven documented more than 100 sightings of one or more fin whales.

Usually there were one to four animals, sometimes more. Groups of around 150 whales were even registered twice in the historic feeding area, the team reports in the specialist magazine “Scientific Reports”.

Fin whales, which can weigh over 70 tons, feed primarily on krill and small schooling fish. According to the researchers, they had been almost wiped out by whaling in the southern hemisphere. In 1976, hunting them was already banned there – even before the whaling moratorium that applies to all large whales.

In the 2000s, more fin whales were finally sighted off the Antarctic Peninsula. Herr and Meyer’s team counted the whales using helicopter and drone flights as well as sightings from the ship.

“The observed group sizes of up to 150 animals are unique today and were last described at the beginning of the 20th century, i.e. at the beginning of whaling in Antarctica,” said Helena Herr, first author of the study. “Even if we don’t know the total number of fin whales in Antarctica due to a lack of synchronous observations, it could be a good sign that the fin whale population in Antarctica is recovering almost 50 years after commercial whaling was banned,” added Bettina Meyer.

The increased stocks affected the entire ecosystem of Antarctica. According to the information, the excrements of the fin whales provide more nutrients in the upper water layers. This benefits other living beings. “The microorganisms that benefit from the richer supply of nutrients absorb a lot of carbon dioxide and thus make an important contribution to the reduction of carbon in the atmosphere,” said Herr.

“The study confirms the ongoing good recovery trend in fin whale stocks in the Antarctic,” said whale expert Heike Zidowitz from the nature conservation organization WWF. But the dangers are not completely averted. “The growing commercial krill fishery, especially around the Antarctic Peninsula, harbors the danger of bycatch in the nets and reduces the availability of food.” Feed krill heavily.