Scientists say mysterious ‘quack-like’ sounds in ocean may be whales talking

By Stephen Beech

Mystery "quack-like" sounds detected in the ocean over 40 years may have been whales talking, suggests a new study.

The noises were picked up in the Southern Ocean, off the coast of New Zealand, in July 1982.

But the source of the four short bursts resembling a quack - dubbed the “Bio-Duck” - has never been definitively identified.

Scientists based in New Zealand recorded the unidentifiable sounds as a part of an experiment to characterize the soundscape of the South Fiji Basin.

Researcher Dr. Ross Chapman, of the University of Victoria in Canada, said: “The sound was so repeatable, we couldn’t believe at first that it was biological.

“But in talking to other colleagues in Australia about the data, we discovered that a similar sound was heard quite often in other regions around New Zealand and Australia.”

The researchers came to a consensus that the sounds had to be biological.

Dr. Chapman said: “I became involved in the analysis of the data from the experiment in 1986.

“We discovered that the data contained a gold mine of new information about many kinds of sound in the ocean, including sounds from marine mammals.

“You have to understand that this type of study of ocean noise was in its infancy in those days.

"As it turned out, we learned something new about sound in the ocean every day as we looked further into the data - it was really an exciting time for us."

But the "quack" sounds have never been conclusively identified.

Dr. Chapman says there are theories they were made by Antarctic Minke whales, since the sounds were also recorded in Antarctic waters in later years.

However, there was no independent evidence from visual sightings of the whales making the sounds in the New Zealand data.

No matter the species, Dr. Chapman believes that the sounds could be a conversation.

He explained that the data was recorded by an acoustic antenna, an array of hydrophones towed behind a ship.

The uniqueness of the antenna allowed the research team to identify the direction the sounds were coming from.

Dr. Chapman said: “We discovered that there were usually several different speakers at different places in the ocean, and all of them making these sounds.

“The most amazing thing was that when one speaker was talking, the others were quiet, as though they were listening.

"Then the first speaker would stop talking and listen to responses from others.”

He presented his analysis of the mystery recordings, as well as further evidence that the work was a conversation between multiple animals, at a virtual meeting of the Acoustical Society of America.

Dr. Chapman added: “It’s always been an unanswered issue in my mind.

"Maybe they were talking about dinner, maybe it was parents talking to children, or maybe they were simply commenting on that crazy ship that kept going back and forth towing that long string behind it.”