Question: Why do grunters grunt?
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We may think of fish as silent animals, but hundreds of species of fish worldwide are known to make sounds, and grunter fish are no different. If you have ever been inland fishing up north, you might be familiar with grunting fish and found yourself wonder why they are making such a strange sound. Grunter fish is a common name for a variety of fish in Australia. Sooty grunter or black bream is what most fishermen will be familiar with. It is a large, tasty and sustainable fish that is loved by both indigenous and recreational fisherman.
![One species of bream communicates using verbal sounds. It is assumed they use the grunting noises to ward off predators and to find a mate. One species of bream communicates using verbal sounds. It is assumed they use the grunting noises to ward off predators and to find a mate.](/images/transform/v1/crop/frm/silverstone-ct-migration/f4c00f74-fc42-4b03-8e4e-1db212772783/r0_0_1000_750_w1200_h678_fmax.jpg)
"[Grunter or grunting] are terms to describe the fact that they talk or communicate," Recfishing Research program coordinator Matt Barwick says. No behavioural studies have been done on what sooty grunters are grunting about, but Barwick can make an educated guess.
"A lot of fish species communicate for a lot of different reasons; generally, it is about warding off a predator, finding mates and staying close to them".
Fish can do more than just grunt: Clown fish chirp and click, New Zealand big eyes pop, and the plainfin midshipman grunts, growls, and can make a constant humming noise like a cross between a swarm of bees and an electric guitar amplifier which lasts for longer than an hour.
Fish have evolved vocal organs very differently to our own. In humans, air passes from our lungs over vocal folds in our larynx which vibrate. Bony fish (teleosts) have evolved to have the largest range of sound-producing organs among all vertebrates, such as snapping their jaw teeth, vibrating rigid or bony body parts, plucking stretched tendons or using specialised organs – such as "drumming muscles" – combined with their swim bladder.
With the increased amount of boats, cars and industrial uses in our waterways, how do fish make themselves heard to attract mates and keep the bad guys away? According to a study by Auburn University in the United States, they shout. Just like humans raising their voices in noisy environments – called the Lombard effect – fish can raise their voices over the noise to make themselves heard. This was discovered when researchers put a fish known to growl and knock, blacktail shiners, in a loud environment and watched to see if they would move closer together. They were pleasantly surprised to find they increased their volume.
The researchers plan to explore this in other fish species, and see how sounds affect growth and reproduction.
Response by: Jesse Jorgensen-Price, Fuzzy Logic
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