Study finds fin whales return to Antarctic waters

From afar, it looked like a thick fog across the horizon. But as the ship approached, ocean bubbles like 150 whale fins, the second largest creatures on the planet, sank and darted onto the surface of the water.

Six weeks after a nine-week expedition, near the coast of Elephant Island, northeast of the Antarctic Peninsula, researchers have found the largest concentration of fin whales ever documented.

“It was one of the most exciting observations I received,” said Helena Hare, a marine mammal ecologist at the University of Hamburg. “The fin whales looked crazy because of the load of food they encountered. It was very exciting.”

Dr. Hare and her colleagues have documented the return of large numbers of fin whales to the waters that were their historic feeding grounds in A research paper published Thursday in the journal Scientific Reports. The research provides a glimmer of good news in what is otherwise a troubling landscape of global biodiversity, and the species of ocean dwellers in particular.

Humans Rapid extinction at an unprecedented rateAccording to UN estimates. in the oceans modern modeling It has been estimated that global warming caused by continued emissions of greenhouse gases could lead to the mass death of marine species by the year 2300.

However, the fin whale population recovery offers “a sign that if you enforce management and conservation, there are opportunities for the species to recover,” said Dr. Hare.

For most of the 20th century, the landscape in the waters around Antarctica was markedly different. Between 1904 and 1976, commercial whalers descended on rich feeding grounds and killed an estimated 725,000 fin whales in the Southern Ocean, draining their populations to less than 1 percent of their pre-whaling size.

At the parties to the International Whaling Commission at the end Voted to ban whaling in 1982After a decade-long campaign by environmental groups to save whales, a number of species – including fin, sperm and whales – have already been hunted to the brink of extinction.

But after 40 years of commercial whaling bans, researchers studying other species in the Southern Ocean are beginning to notice the return of increasing numbers of fin whales.

This was the case in 2013 for Dr. Hare and her colleagues. At the time, they were investigating minke whales when they came across large populations of fin whales “by chance”. They decided to apply for funding to study the revival of fin whales.

In 2018 and 2019, researchers returned to the Antarctic Peninsula to conduct the first dedicated study of fin whales. Through aerial surveys, researchers have recorded 100 groups of fin whales, ranging in size from one to four individuals. They also documented eight large groups of up to 150 whales that gathered to feed them.

Jarrod Santora, a National Oceanic and Atmospheric Administration fish biologist who was among the first researchers to document the fin whale population increase while studying krill, said the survey “confirms that this pattern is still continuing and is emerging stronger.” (He was not involved in this new research.)

Whale researchers have warned that not all whale species have recovered successfully since whaling was banned. Sally Mesrush, a fish biologist who has studied whales since 1979 and was not involved in the research, described fin whales as “very successful.” Unlike other species, such as blue whales, fin whales can forage over great distances and feed on a variety of food sources.

Scientists are not sure why some of the clusters are so wide. Dr. Hare noted that the sightings they saw had at least some similarities with historical reports written before the widespread spread of commercial whaling. For example, naturalist William Spears Bruce described seeing whales appearing and erupting “from horizon to horizon” on an Antarctic expedition in 1892.

Recent research has suggested that bouncing off whale populations is beneficial not only to whales but also to the entire ecosystem, through a concept known as the “whale pump”. Scientists hypothesize that when whales feed on krill, they excrete iron, which was trapped in the crustaceans, back into the water. This, in turn, could boost phytoplankton, which are microscopic organisms that use carbon dioxide in photosynthesis and serve as the base of the marine food chain.

Dr. Santora said that because fin whales bring krill to the surface of the water, they could also facilitate the success of other predators, including seabirds and seals. “There is much more cooperation and symbiosis than we give credit to the ecosystem.”