Researchers have discovered a new population of blue whale, according to a paper recently published in Endangered Species Research. The researchers behind the paper recorded a novel blue whale song and verified it in the western Indian Ocean. The song was heard from the Arabian Sea coast to the Chagos Archipelago in the central Indian Ocean and even as far as Madagascar. 

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A blue whale tail emerging from the ocean.

Blue Whales are the largest mammals ever known on the face of the Earth. While available in all oceans (except the Arctic), various unique subspecies show up in different regions. Each population of blue whale is identified by its unique song. 

Lead researcher and co-author of the study Dr. Salvatore Cerchio first recorded the sound in 2017 while researching Omura’s whales. Dr. Cerichio, who is also the Director of the African Aquatic Conservation Fund’s cetacean program, has been leading research into the new population since then. 

Part of a blue whale emerging from the ocean and expelling water.

“It was quite remarkable,” said Cerchio, “to find a whale song in your data that was completely unique, never before reported, and recognize it as a blue whale.” Given that researchers have extensively studied whale sounds, this finding was a big deal in scientific circles. “With all that work on blue whale songs, to think there was a population out there that no one knew about until 2017, well, it kind of blows your mind,” Cerchio added.

The findings lead some researchers to raise concerns about the possibility of additional undiscovered blue whale population. According to Andrew Willson from Five Oceans Environmental Services LLC, who was part of the research team, blue whales and Arabian Sea Humpback whales may comprise several unique subspecies. 

Part of a blue whale emerging from the ocean.

“These populations appear to be unique among baleen whales, in the case of the Arabian Sea humpback whales because of their year-round residency in the region without the same long-range migration of other populations,” Willson said. The finding now opens doors for researchers to determine the status of the unique subspecies. 

Meanwhile, Suaad Al Harthi, Executive Director of the Environment Society of Oman, touches on the balance between looking into this new population while also saving the endangered Arabian Sea Humpback. “For 20 years we have focused work on the highly endangered Arabian Sea humpback whale, for which we believe only about 100 animals remain off the coast of Oman. Now, we are just beginning to learn more about another equally special, and likely equally endangered, population of a blue whale,” said Al Harthi.


Images via NEAQ