In the wake of humpback whales in the icy waters of Antarctica | TV5MONDE

In the frozen sea of ​​Antarctica, the Colombian scientist Andrea Bonilla recorded with her camera the tail of a humpback whale, the human equivalent of a fingerprint.

Since 2014, he has been working with other scientists to develop a catalog based on visual analysis of the tail fins of these large whales, which can be up to 18 meters long and weigh up to 40 tons.

“What we are doing is following the story of each individual,” a researcher from the American Cornell University on board the ARC Simon Bolivar, a ship of the Colombian Navy, explains to AFP.

His team has identified 70 whales over the years and hopes to track down some of them to study their evolution, movements or even their growth.

“The color and patterns of each whale (tail) is unique, it's like a fingerprint, so what we do is we look at the different markings that they have, the different scars, and based on that and the color, we can know exactly which individual it is,” Andrea Bonilla told AFP.

Threatened with extinction by commercial fishing for years, the mammal has benefited from an international hunting ban since 1985, which has allowed its population to recover.

Today, there are 84,000 humpback whales in the world, according to the Red List of the International Union for Conservation of Nature.

A study published in late February in the journal Royal Society Open Science, however, found that in addition to collisions with ships and noise, they were also suffering from the effects of climate change, which is altering marine ecosystems and the availability of prey.

Map of the continent

Between 2012 and 2021, the number of humpback whales fell by 20% in the North Pacific, from 33,000 individuals to just over 26,600, according to this study, which was based on the largest set of photo data ever created to identify a large marine mammal.

Photographic identification is common in the study of marine mammals, although caudal fin identification is more commonly used with humpback whales due to their unique markings and habit of sticking their tails out of the water when diving.

The species migrates very long distances between warmer breeding grounds and food-rich areas in cold regions.

“They take advantage of this large biomass of food that is here (in Antarctica) and, for several months, they just accumulate energy,” explains Ms. Bonilla.

From May, they “start moving back towards the tropics” and experience a “fasting” period of about six months, she continues.

Inside Simon Bolivar's ARC, she uses an image editing program to crop photos and zoom in on details.

From the photos taken, she also draws on paper the details of the photographed tails.

The goal of Colombian scientists is to compile a comprehensive catalog of humpback whales to compare with those existing in “other breeding areas” and to consolidate a map of the continent in order to then implement conservation initiatives.

“If the whale always comes to the same area to reproduce, it is important to protect these areas. If they disappear or are disturbed, the whale will have nowhere else to go,” warns Andrea Bonilla.

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