After over a century of absence, the majestic sei whales have returned to the waters off Argentina's Patagonian coast. These giant blue-grey creatures were once on the brink of extinction due to relentless hunting during the 1920s and 1930s. Whaling ships, operating along and beyond Argentina's shores, decimated the sei whale population, leading to their disappearance from the region.
However, thanks to global bans on commercial whaling enforced in recent decades, the sei whales are returning to their erstwhile waters.
Mariano Coscarella, a biologist and marine ecosystem researcher at Argentina's CONICET scientific agency, explained to Reuters that they had disappeared because they were hunted. “They did not become extinct but were so reduced that no one saw them,” he said.
"After nearly a century of being hunted to near extinction, sei whale populations are now bouncing back and returning to their former habitats," he added.
It has taken decades for sei whale numbers to rebound sufficiently for sightings to occur again, he further said, adding in this case, it took over 80 years.
According to Mr Coscarella, these whales reproduce every two or three years, "so it nearly took 100 years for their population to reach a level where people could notice their presence."
Sei whales belong to the baleen whale family. They are characterised by their sleek, streamlined bodies, typically bluish-grey in colour. These whales are known for their distinctive tall, curved dorsal fin and their relatively small, pointed flippers.
Sei whales can reach lengths of up to 62-66 feet and weigh up to 28-45 metric tons. They feed on small fish and plankton by filtering water through their baleen plates.
Argentina's CONICET team recently fitted some sei whales with satellite trackers to monitor their migration patterns. The project was funded by National Geographic's Pristine Seas project. They gathered valuable footage of the whales in action via drones and underwater recordings.
Mr Coscarella said this was “a success of conservation on a global scale”, attributing the recovery to the worldwide ban on whaling.