Scientists quack minke mystery

A MYSTERIOUS noise is heard occasionally in the southern oceans and off the coast of Australia.

The so-call ‘bio-duck’ sound first came to the attention of sub-mariners at the height of the Cold War in the 1960s. Did it come from a Soviet underwater detection system or was it produced by a sea creature? Listening devices, placed on the Antarctic seabed, recorded the mysterious sound but the source remained elusive. Now a team, led by Denise Risch at the Northeast Fisheries Science Centre, Woods Hole, Massachusetts, claim to have solved the mystery. The low-pitched repetitive pulses, with three- to four-second intervals between them, are said to resemble the low-pitched quacking of a duck. However, listening to them on the internet, I couldn’t detect a resemblance. A slight drop in frequency as the sound progresses was a clue to its possible source — whale calls usually fall in pitch.

Timing provided another piece of the jigsaw: the noises are heard in winter and spring. If their source is an animal, it’s likely to be one present only at these times of year. Minke whales became the prime suspects. They frequent Antarctic waters but their newborn calves can’t cope with extreme cold, so they migrate northwards in winter and spring to give birth. Being the name of a man, ‘minke’ should perhaps begin with a capital letter. Meincke was a Norwegian whaler who mistook this species for the blue one and was lampooned for his incompetence.