Undersea crooners: whale songs are incredibly
complex and change every year.
Image courtesy of iStockphoto

Dr McCauley, of Curtin University of Technology’s Centre for Marine Science and Technology, has spent 20 years studying the songs of blue whales, humpbacks and minkes, as well as the sounds made by fish, and is recognised as one of the world’s foremost expert on the phenomenon.

Yet, he claims, researchers still know “next to nothing” about biological sea noise, particularly whale song.

“I recognise about 10 per cent of what I hear, but I don’t often know exactly what its specific purpose might be,” he says.

“Whale songs are incredibly complex, and there is a vast amount to learn. Humpbacks are probably the best know. They have a song and they change it each year.”

Rather like humans in conversation, whales use sounds to attract or impress a mate, to scare off a rival for their affections, or to tell each other where the food is. The song between a mother and a calf is different again.

“The young adults are taught that particular year’s song by a ‘song master’,” Dr McCauley says.

He has tracked a single juvenile swimming beside a single adult male.

“The adult was singing the song and the juvenile was repeating it and making mistakes and getting out of time and the adult was repeating it again.”

Varying in pitch, intensity and length, some of the sounds travel hundreds of kilometres.

“You can relate whale song to the complexity of bird song, while fish noise can be related to frog sound,” he says.

Dr McCauley has highly sensitive sea noise loggers to pick up the songs of humpbacks, minkes and pygmy blue whales – a sub-species of the blue whale and almost as large – in the Perth Canyon, near Rottnest Island, and off the Kimberley coast.

He wants funding to place loggers off Ningaloo, so that the route of the whales as they pass up and down the WA coast to breed and feed, is more comprehensively tracked.

Tracking whale and fish noise enables researchers to extract information about breeding, spawning and population trends.

“It also has huge management implications,” he says. “We spend a lot of time and effort untangling trapped whales, dolphins and other sea life from lobster pots and fishing lines. If we could be more aware of when and where they move, it would save a lot of effort and unnecessary deaths.”

Sea noise loggers would also assist the study of much of the other incredible sea life of the world’s largest fringing coral reef.

“There are quite a lot of fish that make noise at Ningaloo; they’ve just never been studied,” Dr McCauley says. “And those that don’t make noise, we can often track by following the sounds made by their prey. They will be where the food is.”