South Australians Urged to Eat Oysters and Donate Shells to Help Restore Native Reefs

Residents of South Australia are being encouraged to enjoy local oysters — then clean and donate the empty shells for a state-wide initiative aimed at reviving once-vast native oyster reefs. The offer comes as part of a broader push to rebuild marine ecosystems weakened by a destructive 2025 toxic algal bloom.

The initiative has been led by marine ecologists including Dominic McAfee (University of Adelaide) and supported by community-focused conservation organisation OzFish. Volunteers are asked to clean, sun-dry and drop off oyster shells, which will then form the substrate for new shellfish reefs — giving baby oysters a surface on which to settle and grow.

Why oyster reefs matter now more than ever

Native oyster reefs once stretched along more than 1,500 km of South Australia’s coast, supporting fish habitats, stabilising seabeds, and filtering water. But decades of dredging and overharvesting reduced them to near-extinction.

The 2025 harmful algal bloom — which caused mass marine die-offs and widespread ecological damage — has sharpened focus on the need for restoration. Oyster reefs act as natural filters: each adult oyster can draw litres of water through its gills daily, removing excess nutrients and improving clarity.

Rebuilding reefs, proponents say, won’t just restore lost ecosystems — it will make coastal waters more resilient to future environmental shocks.

How the shell-donation scheme works

• Eat local oysters — order from SA growers or seafood retailers.
• Clean and sun-dry the shells — ensuring they’re free from residue or organic matter before donation. Гардиан+1
• Drop off at designated collection points — volunteers and community groups liaising with OzFish and university teams will gather the shells.
• Shells are then packed into biodegradable mesh bags or reef modules and placed on the seafloor to act as “reef-starter” substrate for native oyster (flat oyster) larvae.

The project also uses other reef-building materials — such as limestone and ceramic tiles — where shell supply is insufficient. But shells remain crucial because they replicate the natural substrate oysters historically used.

What authorities and scientists hope to achieve

The state government has backed plans to create dozens of new shellfish reefs, combining donated shells with engineered reef modules. Recently launched programmes aim to deploy shell-based reefs along the coast, restoring lost habitats and boosting marine biodiversity.

Officials say reef restoration could help buffer future environmental crises, improve water quality, support fisheries, and even help seagrass recover by reducing nutrient and sediment loads.

For many South Australians, the shell-donation call is also symbolic: a way for ordinary people to contribute meaningfully to healing the coast after ecological disruption. As one marine scientist says, shell donation is “a way for the public … to get involved and find purpose” amidst the grief caused by recent mass die-offs.

What you can do — and why it matters

If you’re in South Australia and buy oysters:

• Rinse and sun-dry the shells — then check local recycling/collection points organised by OzFish or community environmental groups.
• Encourage friends, family or restaurants to participate — collective shell donations make reef rebuilding more feasible.
• Support local conservation efforts: even if you’re not near the coast, recycled shells and community funding help scale up restoration efforts.

In doing so, each shell becomes a building block — not just for a reef, but for a healthier, more resilient marine environment. For a coast still reeling from ecological disaster, small actions like shell recycling may help restore what was lost, one oyster at a time.