The calls of chattering birds and chirping crickets are common sounds, yet the oinks and grunts of fish are far from familiar.

Key points: Scientists use hydrophones to listen to underwater noises to monitor river health, especially when environmental water is released

Scientists use hydrophones to listen to underwater noises to monitor river health, especially when environmental water is released Fish, snails, insects, and even the river bed all give off distinctive sounds that scientists assess for river health or otherwise

Fish, snails, insects, and even the river bed all give off distinctive sounds that scientists assess for river health or otherwise One ecologist says the idea has been around since Aristotle, but has only been used by modern-day scientists for the past 20 years

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 5 seconds 5 s This is what at barred grunter sounds like under water at Talaroo Station, North Queensland. Supplied: Biosphere Soundscapes ( Supplied: Biosphere Soundscapes ) Download 148.1 KB

But the bizarre babbling of aquatic life has allowed scientists and environmentalists to gain a greater understanding of river health across Australia, particularly when environmental water is delivered.

A global leader in real-time sound processing, Toby Gifford, said fish, aquatic insects, and the physical processes of the river "all make sound".

"It's much like being in a forest at night with a soundscape of cicadas … it sounds quite similar under water," Dr Gifford said.

Environmental water project officer for the Goulburn-Broken Catchment Jo Deretic has been recording the sounds of aquatic life since 2008.

It has helped her monitor how animals and insects respond to an influx of water.

Jo Deretic sets up sound recording equipment in the Black Swamp, NSW, to monitor how aquatic life responds to the delivery of environmental water. ( Supplied: Jo Deretic )

"The environmental water was first delivered to one of our swamps here in Shepparton and we decided to put some acoustic recorders out to see what would happen," Ms Deretic said.

"The response was amazing. We had things calling pretty much straight away as soon as water hit the swamp.

"It [the sounds] shows the sites are havens and hotspots for the diversity of different species that might be struggling with really dry conditions or drought."

A researcher installs hydrophones in the Noosa River, Queensland. ( Supplied: Biosphere Soundscapes )

An orchestra of snails and insects

Ms Deretic has overseen the installation of eight recording devices in the Goulburn and Broken Rivers.

The sounds are recorded with waterproof microphones, known as hydrophones.

"We can hear snails! They'll get on the hydrophone and start trying to eat it so you can hear them rasping," she said.

"We listen for birds, we also listen for frog response and we're just getting into the space of listening to aquatic insects.

"Unfortunately for us down here in Victoria, a lot of fish don't talk like some of the fish up in Brisbane.

"But the insect sounds are showing us that the diversity does change very quickly and the response [to environmental water] is quick.

"It's just a plethora of sound."

This researcher was knee-deep in water while installing sound recording equipment at the Black Swamp in New South Wales. ( Supplied: Jo Deretic )

What do these sounds tells us about the water health?

Dr Gifford said around 20 per cent of freshwater fish make vocalisations.

"Grunters and catfish in Australia make grunts and oinks and they're quite distinctive," he said.

The creaks and chirps from beetles are also a commonly recorded noise, along with the flatulent-like sound of methane escaping from sediment along a creek bed.

"There is a sound from the interaction of flowing water with the bottom of the river that can give a sense of roughness," Dr Gifford said.

However, more research was needed to understand the link between underwater sound and ecological condition.

"The simple equation is more sound equals better ecosystem health, however that's not always going to be the case," Dr Gifford said.

"Catfish, in some places, are quite invasive so being able to listen for that gives us a sense of how far an invasion front has reached.

"Similarly, there's a lot of noisy aquatic insects that are more tolerant of degraded environmental conditions, so if you're hearing a lot of that then it's actually an indicator of poor ecosystem health."

Ecologist Dr Simon Linke recording aquatic sounds at Talaroo Station in North Queensland. ( Supplied: Simon Linke )

Ecologist Simon Linke has championed the science of 'eco-acoustics' as a way of researching freshwater ecosystems.

"It's [eco-acoustics] actually been around for millennia, as Aristotle described the calls of birds and the calls of fish in some of his writings," Dr Linke said.

"But it's only been used to actively monitor environments for the past 10 to 20 years, and for freshwater systems it has only been used for the past five to 10 years."