Seychelles is a dream holiday location for many, but early in the 20th century, it was a popular hunting ground for whalers. Luckily, in 1978, the Republic of Seychelles successfully lobbied to protect the Indian Ocean from whaling. Until now, it was unknown if blue whales even came back to this area, but scientists have now confirmed their return.
Over two seasons (November 2020 and 2021), scientists from the Florida International University, Oregon State University, and the University of Seychelles investigated an area of the ocean where there had been previous opportunistic sightings of blue whales back in October 2017. The team conducted visual surveys and a diver-deployed acoustic recorder that could obtain year-round recordings.
The team was able to record 23 species, including the confirmation that blue whales now visit the area, specifically, the pygmy blue whale (one of four subspecies we know to exist).
"It is remarkable to know that the largest animal on earth swims here," Dr Jeremy Kiszka, a biology professor at Florida International University and a research associate at the Island Biodiversity and Conservation Centre at the University of Seychelles, said in a statement emailed to IFLScience.
"Never in my life would I have imagined that the biggest animal on planet earth cruises our oceans here in Seychelles," said Dillys Pouponeau, a research assistant at the SOSF D’Arros Research Centre. “To me this was big news because it reflects the productivity of our oceans. It shows how regulations have helped to protect this species after whaling.”
The team were also able to identify which blue whale population the whales belonged to – the northern Indian Ocean. They found that these populations spend months in the region (primarily during March and April) and possibly could even be breeding there to produce their cute calves.
"This means the Seychelles could be really important for blue whales," Dr Kate Stafford, one of the lead investigators, told the 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."
It comes as welcome news for an area that holds a deadly past for these mammals, having previously been an opportunistic whaling ground for ships traveling to and from the Antarctic. In the 1960s, whalers killed 500 blue whales near Seychelles and it's estimated that they removed over 12,000 pygmy blue whales from the Indian Ocean as a whole.
Despite restrictions on whaling, and other conservation areas having seen blue whale numbers bounce back, experts believe that there is more work to be done to ensure the survival of these gentle giants.
“Blue whales are protected because they are no longer legally hunted, but they still face a range of threats," explained Kiszka. "Shipping traffic causes noise pollution and can lead to collisions. Climate change is changing the distribution and abundance of their key food, krill.”
The study is published in Endangered Species Research.