Nuclear bomb detectors find a hidden sub-species of blue whales
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A nuclear bomb detection system has found a large group of massive blue whales of a previously unknown population hiding deep in the oceans for decades, according to a recent scientific study.
A team of scientists led by the University of New South Wales (UNSW) Sydney discovered a new population of pygmy blue whales, the smallest subspecies of blue whales, in the Indian Ocean, using data provided by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), that monitors international nuclear bomb tests.
"I think it's pretty cool that the same system that keeps the world safe from nuclear bombs allows us to find new whale populations, which long-term can help us study the health of the marine environment," says UNSW Professor Tracey Rogers, marine ecologist and senior author of the study.
After analyzing the data, the researchers discovered that had not previously been heard before. The researchers identified the whale group when the CTBTO's microphones captured a particular blue whale song, of which frequency and tempo were analyzed. The team concluded that these sounds were not similar to any previously recorded whale sounds.
"At first, I noticed a lot of horizontal lines on the spectrogram. These lines at particular frequencies reflect a strong signal, so there was a lot of energy there," said Dr Emmanuelle Leroy, the lead author of the study, in a statement. "Thousands of these songs were being produced every year. They formed a major part of the ocean's acoustic soundscape. The songs couldn't have just been coming from a couple of whales — they had to be from an entire population."
According to scientific data, songs of blue whales can travel anywhere between 125 to 310 miles underwater though they remain mostly inaudible to the human ear.
The pygmy blue whales are generally 24 metres long. Although confirmation of a species comes with visual observation, the researchers say it is difficult and "unlikely to be verified" soon because of its purely wild nature.
"Discovering a new population is the first step to protecting it," says Dr Leroy. The study, published in Scientific Reports, is expected to give a whale survival guide of how the species adapted to warming ocean temperatures over the past 18 years and of possible evolution.