Western Pacific Biotwang Mystery: Puzzling Metallic Sound Source In Mariana Trench Finally Discovered

Oddities
Western Pacific Biotwang Mystery: Puzzling Metallic Sound Source In Mariana Trench Finally Discovered Majestic Whale Encounters10 Roderick Eime / Flickr cc

Scientists have finally discovered the source of a strange sound recorded near the Mariana Trench. The metallic sound has been dubbed as Western Pacific Biotwang.

It was recorded by seafaring robots known in the marine world as “passive acoustic ocean gliders”. As reported by sources, scientists now believe the sound could be the call of a whole new type of whale.

What You Need to Know About the Whale

According to researchers, the newly discovered sound could be the call of a minke whale. It is a type of baleen whale, which is not abundantly found.

The whale produces sounds that span frequencies that reach as low as 38 hertz and as high as 8,000 hertz, according to a Live Science report. Drawing a comparison with humans, the report also laid down the fact that humans perceive sounds that are between 20 and 20,000 Hz.

“It’s very distinct, with all these crazy parts,” said faculty research asst. at Oregon State University, Sharon Nieukirk.  “The low-frequency moaning part is typical of baleen whales, and it’s that kind of twangy sound that makes it really unique. We don’t find many new baleen whale calls.”

Also, researchers believe the Western Pacific Biotwang was produced by a dwarf minke whale found off the coasts of Australia. They further added that there are several types of minke whales and not much is known about their behavior.

“We don’t really know that much about minke whale distribution at low latitudes,” said Nieukirk. “The species is the smallest of the baleen whales, doesn’t spend much time at the surface, has an inconspicuous blow, and often lives in areas where high seas make sighting difficult. But they call frequently, making them good candidates for acoustic studies.”

The Robots

The autonomous seafaring robots that captured the call are known as Passive Acoustic Ocean Gliders. The Journal of the Acoustical Society of America states the glider was equipped with a custom-designed and in-built passive acoustic recording system. The glider could dive up to 3,280 feet below surface, it added.

Acoustic signals were received by a single omnidirectional hydrophone, amplified by 36 dB, and recorded at 194 kHz sample rate and 16-bit resolution. The paper further states the system was optimized for collecting data in the frequency range 15 Hz to 97 kHz.

As a matter of fact, it was well suited for recording sounds made by both baleen and toothed whales. The five-part Western Pacific Biotwang, that lasted 3.5 seconds, was recorded both in winter and spring. Scientists are yet to determine the exact meaning of the whale’s call.