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University of Victoria biologists have discovered that fish can be identified by sound alone, finding that even closely related species produce distinct vocalizations — a breakthrough that could transform how scientists monitor and protect marine life.

University of Victoria biologists have discovered that fish can be identified by sound alone, finding that even closely related species produce distinct vocalizations — a breakthrough that could transform how scientists monitor and protect marine life.

Using passive acoustics, the researchers identified unique sounds for eight different Vancouver Island fish species in their natural habitats. They then developed a machine learning model that can predict which sounds belonged to which species with up to 88 per cent accuracy.

This could have positive implications for marine conservation efforts and allow scientists to monitor specific fish species using acoustics, said Darienne Lancaster, a PhD candidate in biology who led the project.

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“We knew previously that many fish were making sounds in the wild, but we didn’t know which sounds belonged to which species, or if it was possible to tell these sounds apart. Now, just as we use bird song to identify specific bird species in the wild, we can also listen to fish sounds to identify specific fish species.”

The research, published in the Journal of Fish Biology, is part of the larger fish sounds project run out of the Juanes Lab at UVic.

While researchers have been identifying fish sounds for years, these sounds were typically recorded in a laboratory setting, rather than in the wild and whether different species made unique sounds had never been tested.

Lancaster identified unique sounds for eight different species of fish commonly found on the coast of British Columbia: the black rockfish, quillback rockfish, copper rockfish, lingcod, canary rockfish, vermillion rockfish, kelp greenling and pile perch. This was the first time, in the lab or the wild, that sounds had been identified for the canary and vermillion rockfish.

“It has been exciting to see how many different species of fish make sounds and the behaviours that go along with these calls,” noted Lancaster. “Some fish, like the quillback rockfish, make rapid grunting sounds when they’re being chased by other fish, so it’s likely a defensive mechanism. Other times, fish, like copper rockfish, will repeatedly make knocking sounds as they chase prey along the ocean floor.”

Lancaster used passive acoustic monitoring to record underwater audio and video with a sound localization array designed by project collaborator Xavier Mouy, then analyzed sound characteristics to distinguish between species.

Her machine learning model examined 47 sound features, including duration and frequency, allowing it to detect subtle differences and group species-specific calls.

“The ability of passive acoustics to identify specific fish by sound could be an important new tool for conservationists and fisheries managers,” said Francis Juanes, UVic biology professor and principal investigator on the project.

“Passive acoustics could allow us to estimate population size, monitor activity, and assess the overall health of a fish population in a way that is minimally invasive to vulnerable marine animals.”

The techniques that Lancaster developed can be adapted by scientists all over the world to decipher other fish calls.

Erin Haluschak has been a journalist in British Columbia since 2008. She has worked in print, magazines and online spaces and is a mentor with Digital Women Leaders through the Online News Association... More by Erin Haluschak