For decades, scientists have been baffled by a mysterious sound resonating through the ocean. The sound is said to resemble a quack, thus earning it the nickname “bio-duck.” However, researchers have finally revealed its source as coming from whales that spend a lot of time in the region of Antarctica.
Acoustic recorders have found that the sound comes from the underwater conversations of the Antarctic Minke whale. The sound appears most frequently in winter and spring in the Southern Ocean. Denise Risch, a lead researcher with the project, reportedly stated that it was initially “hard to find the source” of the sound.
There have been a number of suggestions to explain the sound over the years, but until now, no one was able to verify where the sound originated. The repetitive nature of the noise led some to believe that it was made by submarines or other man-made objects. Fish were also suspect for some time.
Last year in February, scientists tagged two Antarctic Minke whales using suction cup tags. They wanted to measure their feeding behaviour and track their progress. The attached tags also held microphones. Researchers were able to use the recorded sound to compare with other existing data on the noise made by the bio-duck sound. They were found to be the same source.
However, it is still unknown what the quacks might mean between the animals. Nevertheless, it is has been revealed that the sounds are made when the whales are close to the surface of the water and just before they dived deep down in the ocean in order to feed. Researchers are confident that solving the mystery of the bio-quack will unlock further secrets about the Antarctic Minke whales.
Dr. Risch has reportedly said that, through the identification of these sounds, researchers will be able to further study the animals. They plan to use “passive acoustic monitoring” to gain a deeper understanding of the creatures. They intend to use the information gathered through tags and recording to track the migration of the whales. The scientists can look at when the animals arrive in Antarctica, how long they stay, and when they leave again. This will show their migration routes and give a better understanding of their movements between different regions.
The team working with Dr. Risch means to study the recordings made by the Perennial Acoustic Observatory in the Antarctic Ocean, (PALAOA) station. The station is located on the ice shelf of Atka Bay in Antarctica. The PALOAOA has been recording sounds continuously in the Southern Antarctic Ocean for a number of years. The name itself, which is not quite an anagram, comes from the Hawaiian word for whale.
The bio quack is not the only sound to have its mysterious source revealed. Another baffling ocean sound, which is known as the “Bloop” was found to be caused by ice cracking in Antarctica. Researchers have yet to discover whether the quack that the whales are making is coming from males or females of the species.
By: Sara Watson