Fish sounds could help scientists understand their marine world

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Turns out Pisces are a talkative bunch. They share everything about which region of the sea has the best food, where predators can hide and, of course, their desire for a mate.

Now researchers from universities in Canada, the United States and Brazil have created an online portal called FishSounds that allows people to view an inventory of sounds made by sea creatures. People can listen to the underwater footage and learn that a sablefish emerges while the orange-coated triggerfish plays a drum roll.

Sarah Vela, senior data manager in a marine environment research group at Dalhousie University and lead developer of the portal, said FishSounds provides researchers with information about whether a fish species is noise and its geographical extent.

“It’s a data set that didn’t really exist before. There are a lot of projects out there that work with orca sounds… normal whale sounds,” she said. “Fish is something that is not studied.”

Scientists use a hydrophone, or underwater microphone, to monitor and record these sounds, which are then identified by an expert, Vela said. The project also involves teaching a computer to associate sounds with specific fish species to build machine learning.

The portal contains data on approximately 1,200 fish species, collected from scientific literature and other sources. Of these, 1,061 made detectable sounds, according to a study published by the portal’s creators in Ecological Informatics last month. The website has records of more than 260 species of fish so far.

“Remote sensing of active and passive fish sounds through passive acoustic monitoring offers the opportunity to answer many questions about ecology, evolution and management in marine, brackish environments and fresh water,” the study says.

Co-author Kieran Cox from Simon Fraser University said that sound is a means for fish to exchange large amounts of information, just like humans. He said that this sharing of information is crucial because the deeper the ocean, the darker it becomes and visual interaction is not always possible.

“Fish have been singing for much longer than birds,” Cox said. “And I mean that only from an evolutionary perspective.”

When he dived in Belize to research fish sounds, he said he could hear fish chewing on coral and seaweed near a reef.

“There’s a certain element of this soundscape that we’re all familiar with, but then you can’t really appreciate it unless you know what you’re listening to.”

Fish, he said, make two types of sounds: active and passive. Active sounds are made intentionally with the mouth or other parts of the body, and can include the release of bubbles, maneuvers of different muscles to produce a specific sound, or moving a bone to produce a repetitive click. Others make a sound like a beating drum with their swim bladders, he added.

The plainfin midshipman, a species of fish native to the eastern Pacific, lives most of its life in the deep, but comes to the intertidal zone to reproduce, where males build nests in which -females lay eggs. Males produce a distinctive buzz to attract a mate, Cox said.

“Basically, the name of the game with the nest is to build almost an amphitheater for sound. Think of it like a concert hall, if you will. It is a cliff nest from which they sing. They use this to attract mates and the females come to lay eggs in these nests. The amount of eggs they give a male is proportional to the quality of their song, the length of their song, and how far they can hear it outside the nest. It’s really a general interaction facilitated by noise,” Cox said.

“If you’re on the beach at night and these fish are there, you can hear them buzzing all night.”

Passive sounds are background sounds that arise in everyday life, such as chewing or digging.

“You can imagine that a fish enjoying a good meal makes a lot of noise, and that noise provides valuable information to other fish nearby,” he said.

There are 34,000 species of fish in the world, and scientists know that more than 1,000 make noise and contribute to background noise, he said. But the seas hold more mysteries of fish sounds that scientists have yet to uncover.

He said learning about fish sounds will help scientists understand, conserve and restore habitats flooded by noise from ships and boats. It could also help understand how fish behave in light of climate change, as some parts of the ocean are warming faster than others, Cox said.

“There is a biological cacophony of sounds in the ocean,” he said. “If we don’t understand that, then we don’t understand how it changes when we introduce large amounts of noise pollution. We won’t even understand how we can save him.”

This report by The Canadian Press was first published on January 24, 2023.

Hina Alam, The Canadian Press

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