There may be only 5,000 blue whales left in the world, but thanks to bomb detectors, researchers may have discovered a new population of the world’s largest animal in the Indian Ocean.
A population of pygmy blue whales was likely detected because their singing was recorded by underwater microphones used to detect bombs.
“We’ve found a whole new group of pygmy blue whales in the mid-Indian Ocean,” University of New South Wales professor and marine ecologist Tracey Rogers, marine ecologist and senior author of the study, said in a statement. statement. “We don’t know how many whales are in this group, but we suspect there are many due to the sheer number of calls we hear.”
The discovery was supported by data from the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), which oversees international atomic bomb tests.
CTBTO, which has been using underwater microphones to monitor atomic bomb tests since 2002, noticed the strong vocal signals in their recordings, hearing different frequencies, tempos and structure.
It was only after the researchers analyzed the data that they realized they had encountered a new population of blue whales in the area.
Researchers may have discovered a new population of pygmy blue whales in the Indian Ocean
The minke whales were discovered because their songs were detected by underwater microphones used to detect bombs. The numbers likely come from a new group the researchers named “Chagos” after a nearby archipelago
Blue whale numbers can travel great distances, estimated to be anywhere from 125 to 300 miles
“Blue whales in the southern hemisphere are difficult to study because they live offshore and don’t jump around — they’re not show ponies like the humpback whales,” Rogers added.
“I think it’s pretty cool that the same system that protects the world from atomic bombs allows us to find new whale populations, which could help us study the health of the marine environment in the long term.”
The sounds were compared to three other known groups of blue whales in the Indian Ocean, as well as to four species of Omura whale songs.
This is likely from a new group, which the researchers have named “Chagos,” after a nearby archipelago.
“We suspect that the whales that sing the Chagos song move across the Indian Ocean at different times,” Rogers added.
“We found them not only in the central Indian Ocean, but as far north as the coastline of Sri Lanka and as far east in the Indian Ocean as the Kimberley coast in northern Western Australia.”
While blue whales can grow up to 30 feet in length in some cases, weighing nearly 200 tons, blue whales are smaller, measuring up to 78 feet in length and weighing nearly 90 tons.
If confirmed by visual observations, the new population of pygmy blue whales would be the fifth discovered in the Indian Ocean.
While blue whales can grow as long as 30 meters in some cases, weighing nearly 200 tons, dwarf blue whales are smaller, measuring up to 100 feet (30 meters) in length and weighing nearly 90 tons.
The sounds were compared to three other known groups of blue whales in the Indian Ocean, as well as four species of Omura whale songs
Blue whales have structured, simple songs, unlike humpback whales
“Without these audio recordings, we would have no idea that there was a huge population of blue whales in the middle of the equatorial Indian Ocean,” Rogers said.
Because blue whales have structured, simple songs (unlike humpback whales), the “strong signal” and frequent occurrence means they probably belong to more than just a few random blue whales.
“Thousands of these songs were produced every year,” said the study’s lead author, Dr. Emmanuelle Leroy, adding that the team looked at data going back 18 years.
‘They formed an important part of the acoustic soundscape of the ocean.
“The songs couldn’t just come from a few whales, they had to come from an entire population.”
Blue whale songs can travel great distances, estimated to be between 125 and 300 miles (200-500 km), and they can change within a species, with some populations of blue whales singing slightly different variations.
“We still don’t know if they were born with their songs or if they learned it,” Rogers said.
“But it’s fascinating that in the Indian Ocean there are animals that are constantly crossing each other, but whales from different regions still retain their distinctive song. Their songs are like fingerprints that allow us to track them as they move over thousands of miles.”
The new findings are published in Scientific Reports.