Mulloway

Sound is an important communication tool for many marine animals, particularly in a murky environment like the river, where light doesn’t penetrate.

Male mulloway use a croaking call produced by vibrating their swim bladder to attract female mulloway into an area to breed.

While the fish vocalisations are fascinating in themselves, the data offers valuable insights into fish population and behaviour to aid species management strategies.  

Researchers at Curtin University have been studying the calls of mulloway, deploying long-term sound recorders to capture thousands of hours of fish sounds. Scientists use the sound data to estimate the number of calling fish and, because males and females produce different sound, they can also estimate the sex ratio of fish in the area. Fish choruses also have different characteristics depending on their location in the river and peaks in ‘singing’ activity are related to tide, lunar cycle and season.

Remarkably, the sound produced by the mulloway’s swim bladder is extraordinarily loud and varied. Sounds have been described as a short grunt or “bup”, long grunt or “baaarp” and short call or “thup”. Listen to some of the incredible calls below.