Blue whales, the world’s largest mammals, are returning to Spain’s Atlantic coast after an absence of more than 40 years. But that might not be good news.
Researchers are investigating whether the climate crisis is causing the creatures to change their habits and return to an area where they were hunted to near extinction.
“I believe the moratorium on whaling was a key factor,” he told The Guardian. “In the 1970s, just before the ban was introduced, an entire generation of blue whales disappeared. Now, more than 40 years later, we are seeing the return of the descendants of the few specimens that have survived.”
The Galicia region is known for its centuries-old whaling industry and for home to a dozen whaling ports. Spain did not ban whale hunting until 1986, by which time the blue whale was virtually extinct in the region.
Search for food or ancestral memory
“I’m pessimistic because there is a big possibility that climate change will have a big impact on the blue whale habitat,” Alfredo López, a marine biologist at a Galician NGO that studies marine mammals, told the newspaper La Voz de Galicia.
“First, because they never venture south of the equator, and if global warming pushes that line north, their habitat will be reduced. And second, if that means the food they normally seek is disappearing, so what we’re seeing is dramatic and not something to celebrate.”
Díaz, in turn, speculates that the creatures may also have returned to Galicia out of a kind of “saudade”, or ancestral memory.
“In recent years, it has been discovered that blue whale migration is driven by memory, not environmental conditions,” he said. “This year there hasn’t been a noticeable increase in plankton, but here they are. The experiences are retained in collective memory and cause the species to return.”
A typical blue whale is between 20 and 24 meters long and weighs 120 tons – the equivalent of 16 elephants – but specimens up to 30 meters and 170 tons have been recorded.