‘Oyster blankets’ use biodegradable mesh to encourage marine life settlement.
As part of Seymour Whyte’s commitment to building sustainable infrastructure and leaving a positive legacy in the communities where we work, our M1 Pacific Motorway Upgrade – Palm Beach to Tugun (PB2T) project team is trialling an innovative, nature-based solution to stabilise the banks of Saltwater Creek at Currumbin on the Gold Coast.
In a first for Seymour Whyte, more than 300 kilograms of oyster shells – sourced from local restaurants and fish markets – have been repurposed into living barriers that enhance biodiversity, prevent erosion, and improve water quality.
A natural solution to erosion control
Ongoing erosion along Saltwater Creek had been damaging vegetation, aquatic habitats, and even a natural oyster bed. Rather than relying on conventional hardscaping, which can disrupt ecosystems, the team worked with OzFish Unlimited to trial a regenerative, nature-based solution.
The approach was informed by successful oyster reef restoration efforts in Moreton Bay and inspired by the Billion Oyster Project in New York.
Recycled oyster shells were UV-treated to remove pathogens and biosecurity risks, then placed in steel cages, quilted baskets, and biodegradable mesh bags (also known as oyster blankets).
These structures mimic natural oyster reefs – creating habitat for marine life, locking away carbon, and naturally filtering the water.
Oyster shells encased in steel cages form living, breathing barriers that support biodiversity and stabilise creek banks.
Small shell, big environmental impact
Oysters are powerful natural living filters – one adult can purify up to 150 litres of water a day.
This trial section has the potential to support up to 2,000 kilograms of live oysters, which could sequester an estimated 240 kilograms of carbon and prevent 734 kilograms of CO₂ emissions through erosion mitigation over three years.
Six-monthly monitoring has shown strong early results:
- April 2024: The first oyster was spotted growing on a recycled shell
- November 2024: Fifteen live oysters were recorded growing on recycled shells
- April 2025: Hundreds of oysters and estuary mussels were observed, along with marine species such as tube worms, fish, stingrays, and crustaceans.
Innovation recognised, with long-term potential
This initiative was highly commended in Seymour Whyte’s 2024 Bright Ideas Award for its creativity and commitment to sustainability.
“This approach supports a circular economy by repurposing waste, reduces the use of carbon-intensive raw materials, and contributes meaningfully to marine conservation.”
— Brooke Larance, Project Environment Manager
Collaboration was key with support from the Department of Transport and Main Roads (TMR) and OzFish Unlimited.
Together, the team navigated complex challenges – from sourcing materials to addressing biosecurity and landfill diversion.
OzFish Unlimited continues to monitor outcomes to inform future applications in waterway rehabilitation.
Project Environment Manager Brooke Larance (second from left) receives a Highly Commended certificate at the 2024 End-of-Year event.
Building smarter, greener infrastructure
This trial is part of Seymour Whyte’s broader strategy to decarbonise operations and deliver enduring environmental and community benefits.
It shows how engineering ingenuity and environmental vision can transform waste into a tool for regeneration.
“This kind of work represents the future of infrastructure – where our projects don’t just minimise harm, but actively regenerate the environments they touch.”
— Brooke Larance, Project Environment Manager
Watch the short video to see how the project team turned oyster waste into a waterway solution that benefits people, the planet, and project performance.
Learn more about our commitment to the environment and sustainability here.
