Washington, United States

In a win for conservation efforts, researchers found that blue whales have returned to a region of the Indian Ocean near Seychelles from where the largest animals on Earth were once wiped out due to whaling. The research, findings for which were published in the journal of Endangered Species Research, was based on a year’s worth of underwater audio recordings which found that the animals spend months in the region.

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What is the study about?

The study published earlier this month is based on researchers and filmmakers who managed to capture the footage of blue whales between 2020 and 2021 which also features in the documentary film Return of the Giants.

According to the National Oceanic and Atmospheric Administration (NOAA), blue whales are the largest animals on Earth and are found in all oceans except the Arctic Ocean. However, their numbers significantly declined during the 1900s after commercial whaling. 

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The International Union for the Conservation of Nature lists blue whales as an endangered species primarily due to commercial whaling which has left a lasting impact on the number of these mammals which is said to be a fraction of what they used to be. 

The study also noted how the Seychelles was once an “opportunistic whaling ground” in the 1960s for Soviet whalers who illegally killed as many as 500 blue whales. 

The study was conducted by a group of researchers and filmmakers during a month-long expedition where one of the lead researchers, Dr Kate Stafford, as per BBC, would spend a few hours each day using a hydrophone in the hopes of capturing the sound of blue whales in the region. 

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This was in addition to a “sound trap” which was reportedly fitted for a year near the seabed close to Seychelles and comprised of underwater microphones, batteries and recording devices. These devices would record 15 minutes of every hour each day. 

What did the researchers find?

The research suggests that blue whales may be using the region as a breeding ground after the mammals’ signature – a very low-frequency – song was caught on record by the fitted a “sound trap”. Blue whales, as per researchers, sing during the breeding season and the song was heard particularly during March and April. 

“This means the Seychelles could be really important for blue whales,” Dr Stafford told BBC. 

“They sing during the breeding season and we think it’s probably the males who are singing, based on what we know about other whales,” added one of the lead authors.

She also spoke about the region being a possible “breeding area or a nursery area”. 

The researcher noted that since the island nation does not receive a lot of ship traffic, it is a “nice, quiet, safe place” for blue whales. 

Seychelles, as a part of the “debt for nature” swap, has formally protected about 400,000 square kilometres around the island, in exchange for having around $22 million of its national debt written off. 

Scientists also found that the blue whales would only communicate when they were not around and that’s why it was only through the analysis of the recordings from the sound trap that they were able to discover blue whales in the region. 

(With inputs from agencies)