For more than 40 years it had disappeared from the Atlantic coast of Spain, but now it seems to be returning to its old habitat: The blue whale. According to the Guardian, the world's largest mammals first reappeared off the coast of the Galicia region in northwest Spain in 2017. Since then, sightings have increased. Experts disagree on why the sea creatures are returning after such a long time. According to them, the climate crisis could be one reason, but also the increasing bans on whaling.

"Return of the descendants"

"I believe that the moratorium on whaling was a key factor. In the 1970s, just before the ban was introduced, a whole generation of blue whales disappeared. Now, more than 40 years later, we are seeing the return of the descendants of the few survivors," the Guardian quotes Bruno Díaz, a marine biologist and director of the Bottlenose Dolphin Research Institute (BDRI) in Galicia. Díaz discovered the first blue whale to return in 2017.

Galicia had a centuries-old whaling industry and a dozen whaling ports, according to the Guardian. Spain did not ban whaling until 1986, by which time the blue whale was all but extinct in the region. According to Díaz, the three specimens discovered so far could be descendants of whales that were native to the marine region at the time. Their return could indicate some kind of homesickness or a form of inherited memory of the old habitat.

"Blue Whale walks by memory"

"In recent years, it has been found that blue whale migrations are controlled by memories and not by environmental conditions," says Díaz. "This year there was no significant increase in plankton, but they are there. Experiences are stored in the collective memory and cause the species to return." According to this, blue whales have a kind of folk memory or cultural knowledge.

The return of the whales could therefore be a good sign. However, not everyone is so optimistic. Alfredo López, a marine biologist with the Galician NGO Cemma, sees it more as a sign of the climate crisis. "I am pessimistic because climate change will most likely have a big impact on the blue whale's habitat. Firstly, because they never stay south of the equator, and if global warming moves that line north, their habitat will shrink. And secondly, if that means that the food they normally eat disappears, then what we are seeing here is dramatic and no cause for celebration," he tells La Voz de Galicia newspaper.

Sea dweller is currently "endangered

So there is no clarity yet on the reasons why the blue whales are returning to their old habitat. According to the World Conservation Union (IUCN), the blue whale has "endangered" status as of the latest survey of 2018. According to the organisation, the number of specimens worldwide is tending to increase. There are still between 5,000 and 15,000 specimens worldwide. It is not only the blue whale that is endangered. Other species such as the sperm whale are also becoming increasingly rare. Amazon Web Services and Capgemini have recently developed an AI that is supposed to track these marine mammals and thus avoid collisions with ships (we reported).

The blue whale is an impressive sea creature. According to the WWF, it is probably the largest known creature that has ever lived on earth. They reach an average body length of 24 to 27 metres and weigh about 130 to 150 tonnes. The heart of a blue whale is the size of a VW Beetle. The largest blue whale found so far was over 35 metres long, the heaviest weighed about 190 tonnes.

Found on: Blauwal kehrt nach über 40 Jahren zu spanischer Küste zurück – Tech & Nature (techandnature.com)