The researchers, including scientists from the University of Seychelles, described the discovery as a “conservation win” after the Soviet whaling fleet decimated the population in the 1960s.

One of the lead investigators, Dr Kate Stafford, told BBC News: “It turns out if you stop killing animals on mass scales and you give them a chance to rebound, they can recover.”

The discovery, published in the Journal of Endangered Species Research, was the result of fixing a “sound trap” to the seabed close to the tiny island nation.

Dr Jeremy Kiszka from Florida International University, a lead scientist on the study, told BBC News that the diversity and abundance of marine mammals in the region was “exceptional”.

One major concern is protecting important areas for blue whales from noise pollution, which travels equally efficiently through the water.

“There’s not a tremendous amount of ship traffic in the Seychelles so perhaps we could think of it as a nice, quiet, safe place for blue whales,” said Dr Stafford.

Saved 79% of original text.