Fish Talk More Than You Think—Mostly About Food and Sex

Scientists have known some fish make sounds but little was known about why or how often they communicated with noise.

Goldfish swimming with mouth open
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Apparently, fish have a lot to say.

A new study finds that fish are much more likely to communicate with sounds than previously thought.

“Instead of being limited to just a few species and families, we found that evidence for acoustic communication is widespread among fishes, occurring across nearly the entirety of the fish ‘family tree,’” lead author Aaron Rice, a researcher at the K. Lisa Yang Center for Conservation Bioacoustics at the Cornell Lab of Ornithology, tells Treehugger.

Researchers found sound communication in “primitive” fish like sturgeons, bichirs, and tarpons, as well as more evolutionarily advanced fish such as sculpins, grouper, and triggerfish.

“What really surprised us is how many times sound production appears to have evolved independently,” Rice says. “My initial hypothesis was that it was ancestral to the group, but the evolutionary modeling suggests that it has evolved independently 33 times. However, it is ancestral for a few major groups of fish.”

Scientists have known that some fish make sounds but little was known about why or how often they communicated with noise.

“When I started grad school, I initially had no idea that fish made sounds to communicate. Growing up being fascinated by fish, my mind was somewhat blown to learn that this world of acoustic communication in fishes was something that hadn’t even occurred to me,” Rice says.

“So in digging into it, there were plenty of isolated accounts of fishes making sounds, and a few great reviews trying to pull the information together, but it became clear (even 20 years ago) that there was not a comprehensive synthesis providing a holistic understanding of what is known about fish sounds.” 

Scientists believed that fish likely used sound for communication and likely even to select mates. Early on, sounds were only studied in a few fish and those were usually those whose sounds could be heard by the human ear above the water’s surface. Later, an underwater microphone called a hydrophone became key for researchers listening to sounds underwater.

Studying Fish Sounds

For their study, researchers studied ray-finned fish. This is the largest class of fish which includes more than 34,000 species.

They studied existing recordings and research papers that discussed and described fish sounds. They also analyzed the anatomy of fish species to see whether they had the right structure to make sounds, including an air bladder and specific muscles and bones. They also researched references in 19th century literature to fish sounds before the hydrophone was invented.

They found that sound communication was evident in 175 of the 470 families analyzed. The results were published in the journal Ichthyology and Herpetology.

Researchers believe the fish are talking about all sorts of things including food and sex.

“We know that it parallels the behavioral functions that we see in tetrapods (frogs, birds, mammals, etc). In many cases it’s a critical component of mate attraction, where males call to attract females to reproduce,” Rice says.

“The other behavioral context is that it’s involved in agonistic displays, where fish are using sounds to scare away predators, or defend food or territories. However, there are plenty of species where we don’t know the exact behavioral function, and that provides plenty of opportunity for discovery.”

Why Fish Sounds Were Overlooked

Fish sound communication was likely overlooked or underestimated in the past for several reasons—in part because researchers studied fish without hydrophones. But even with the underwater microphones, fish can be difficult to hear, Rice says, unless you are listening in the right place at the right time.

“The second reason is that an anthropocentric perspective is pervasive when thinking about what fishes can and cannot do. Simply put, many scientists have viewed the fish through the perspective that if humans can’t do something underwater, then why would fish be able to do it?” Rice says.

“It was initially thought that fish can’t smell underwater because humans can’t smell underwater, even though fish very clearly have nostrils and well-developed olfactory regions of the brain. The same is true for seeing ultraviolet light (which coral reef fish see quite well), as well as producing or detecting sounds. As the technology gets better and cheaper, it will be much easier to hear all of the crazy sounds that fish are making.”

View Article Sources
  1. Rice, Aaron N., et al. "Evolutionary Patterns in Sound Production Across Fishes." Ichthyology & Herpetology, vol. 110, no. 1, 2022, doi:10.1643/i2020172

  2. lead author Aaron Rice, a researcher at the K. Lisa Yang Center for Conservation Bioacoustics at the Cornell Lab of Ornithology