Millions of tiny engineers help to restore health of marine ecosystem in WA

Once mussels attach to the ropes and start developing, their shells provide a surface for seaweed and other marine flora to grow. (Supplied: Byssal)

Beneath the peaceful surface of Cockburn Sound (Derbal Nara), south of Perth, millions of tiny marine engineers are hard at work.

A project is harnessing the remarkable abilities of the humble mussel to help restore the health of the sound.

Cockburn Sound was once home to a thriving mussel farming industry that aquaculturalist Glenn Dibbin worked in for nearly four decades.

Glenn Dibbin has long been a part of Cockburn Sound's mussel farming industry. (ABC Perth: Rachel Stowers)

Over that time he witnessed a "rollercoaster of a boom-bust cycle in regard to seafood and fish life". As commercial mussel farming declined and operators closed or relocated, much of the infrastructure was left idle.

Today some of that infrastructure is being given a new purpose by the Byssal project, which reimagines mussel farming for ecosystem restoration rather than seafood.

The blue mussel is native to Cockburn Sound. (ABC News: Rachel Stowers)

The project was founded by Mr Dibbin alongside Recfishwest, representing the interests of WA recreational fishers, as well as industry partners Indo-Pacific Environmental and Commercial Maritime.

Glenn Dibbin says the ropes act in a similar way to an artificial reef, but are significantly cheaper to set up. (ABC News: Rachel Stowers)

Mussels, like most bivalves, are filter feeders that draw water through their gills, extracting microscopic food particles and, in the process, improving water clarity.

"An adult mussel can filter up to three litres of water an hour," Mr Dibbin said.

"So when we talk about 1,000 tonnes [of mussels], when we start doing those numbers, the zeros … you can't use a calculator, there's so many zeros."

The project gets its name from the byssal threads — "beards" — produced by mussels to help them attach to surfaces. (ABC News: Rachel Stowers)

According to Recfishwest, nearly 80 per cent of the Cockburn Sound's seagrass meadows have been lost since the 1960s.

In addition to providing critical habitat, seagrass meadows also stabilise sediments and store vast amounts of carbon from the atmosphere.

Byssal's mussel farm is close to the Kwinana Grain Terminal jetty. (ABC News: Rachel Stowers)

According to Mr Dibbin, murky water is a key factor in the loss of the area's seagrass.

"The sunlight penetration couldn't get down into the deeper waters, because there's so much activity above them … so mussels, by filtering the water, clean that water so it act