On May 1, 2024, the Argentinian government reported that legislation passed during the 1946 International Convention for the Regulation of Whaling is still compounding—sei whales returned to the South American nation’s coastal waters for the first time in nearly a decade. Mass overhunting during the 1920s and 1930s led these massive blue-grey giants to abandon their native, ancestral waters in Argentina; when species leave their natural habitat, there is often a high risk for extinction or endangerment. “After nearly a century of being hunted to near extinction, sei whale populations are now bouncing back and returning to their former habitats,” said Mariano Coscarella, a biologist and marine ecosystem researcher at Argentina’s CONICET scientific agency, who added that the 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.”
The third largest whale in the world, the sei can grow up to 64 feet (20 meters) in length and weigh up to 31 tons (28 tonnes). It’s also among the fastest whales in the world and is certainly the fastest for its size group. It can swim 31 mph over short distances.
Despite being recognized on the IUCN Red List as Endangered, there are estimated to be 50,000 sei whales in a global population that is trending up.
Apart from sei whales and Argentina, a recent survey in the Seychelles sighted 10 groups of at least a few blue whales, the first such observations since 1966.
Back in March, a New England Aquarium aerial survey team sighted a gray whale off the New England coast last week, a species that has been extinct in the Atlantic for more than 200 years.