Scientists Finally Crack Ocean "Quack" Mystery
After decades of mystery, scientists have discovered the source of the ocean "quack" heard from the depths of the Southern Ocean. The culprit, according to a study published in the journal Biology Letters, is the Antarctic minke whale.
In the study, researchers tagged and recorded at Wilhelmina Bay the so-called "bio-duck" sound off the western Antarctic Peninsula.
Submarine crews first heard the oceanic quack, which consists of a series of repetitive, low-pitched pulsing sounds, in the 1960s.
"For decades, the bio-duck sound has been recorded in the Southern Ocean, but the animal producing it has remained a mystery," Denise Risch of Integrated Statistics told Discovery News.
Antarctic minke whales, it turns out, produce the loud, Donald-Duck-esque sound that every scientist thought was coming from a fish, Risch told Live Science.
In February 2013, Risch's colleagues tagged two Antarctic minke whales (Balaenoptera bonaerensis) with suction-cup tags containing underwater microphones. The researchers meant to study the whale's feeding behavior and track their movements, but ended up unintentionally solving an oceanic mystery.
The noises occur seasonally - every winter and spring - near Antarctica and Western Australia and come in sets spaced about 3.1 seconds apart. Now that researchers have identified their source, they have plenty of data to study from thanks to audio recordings obtained over the past 50 years.
Scientists speculate that the whales use this strange sound as a means of communication or navigation, or possibly for breeding purposes.
"Identifying their sounds will allow us to use passive acoustic monitoring to study this species," Risch said. "That can give us the timing of their migration - the exact timing of when the animals appear in Antarctic waters and when they leave again - so we can learn about migratory patterns."
Not only do these ocean recordings allow scientists to study the Antarctic minke whales, but they offer an alternative research method to controversial Japanese whaling practices.
"It shows killing is not necessary," Risch added.