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Oyster reef restoration and research

Published 24 June 2024 Restoring and researching natural oyster reefs to improve water quality, aquatic habitat and biodiversity.


‘Originally the oyster beds extended from Darling Harbour to the Flats in more or less quantities, but a few years back they became almost extinct from over-dredging.’ NSW Inspector of Oyster Beds, 1877.

Oyster reefs - A forgotten ecosystem

Prior to the 19th century, oyster reefs were a common feature of NSW estuarine and coastal areas providing tremendous environmental benefits.

During early European colonisation, vast quantities of natural oyster reefs were harvested unsustainably for food and as a source of lime for use in construction. Increasing water pollution from upper catchments and disease also impacted the oyster reefs, and by the late 1800s they had all but disappeared in NSW.

Today, oyster reefs don’t provide the benefits like they once did because they have almost completely disappeared. An estimated 99% of oyster reefs are 'functionally extinct' in Australia (1).

An engraving from old newspaper clipping showing oyster shells for lime piled in a large heap. A man stands beside the heap of shells, it is as tall as him.

Oyster reefs – what are they?

The most commonly known reefs are coral reefs, but another form of reef exists - oyster reefs.

Oyster reefs consist of colonies of living oysters and old shell. They can occur in the intertidal zone or be permanently submerged underwater.

Native reef-forming species in NSW include Sydney Rock Oyster (Saccostrea glomerata), Leaf Oyster (Isognomon ephippium), and Native Flat Oyster (Ostrea angasi).

Oyster reefs are culturally important to coastal Aboriginal people and provide a wide range of benefits. These include:

  • providing food, shelter and protection for a diverse range of fish and other marine creatures
  • filtering and cleaning the water, improving water quality, reducing turbidity and supporting the growth of seagrass
  • protecting shorelines by buffering wave energy and enhancing sediment deposition. This supports the growth of other marine habitats such as seagrass beds and saltmarsh which further protect shorelines.

infographic showing benefits of oyster reef and how many litres an average wild oyster filders in an hour - it's 2 litres an hour, 50 litres a day!

What is oyster reef restoration?

The natural recovery of oyster reefs is largely thought to be limited by a lack of suitable hard material for baby oysters (known as spat) to settle.

Oyster reef restoration reintroduces materials such as rock or sterile shells to the estuary floor so the baby oysters can settle and start to regrow a new oyster reef.

Ideally, this occurs in areas with good levels of natural spat settlement. Where there’s not enough wild spat, ‘seeding’ of oyster reef bases, with hatchery-reared spat, may also be needed.

Over time, given the right conditions, these young oysters grow and reproduce, creating a self-sustaining vibrant ecosystem with all the benefits of a natural oyster reef.

What are we doing?

The Oyster reef restoration and research project is learning more about the ecology of oyster reefs and restoring oyster reefs in NSW so they can do their job again – naturally.

This includes working with partners to:

  • deliver landmark oyster reef restoration projects, including at Port Stephens, Narooma and Kamay/Botany Bay, and evaluate these restoration projects to measure the level of success
  • conduct ground-breaking research to learn more about the ecology of the State’s oyster reefs and oyster reef restoration methodology
  • map current oyster reefs to better understand where reefs are and identify where they could be restored. You can check out Oyster reef maps for your local estuary via the DPIRD Fisheries Spatial Data Portal
  • educate the NSW community about oyster reefs and engage them in the restoration of this long-forgotten ecosystem.

What have we achieved so far?

The Oyster reef restoration and research project is delivering some exciting results across the marine estate.

Monitoring of the Port Stephens oyster reef restoration project is revealing that to date, 34 million oysters have naturally recruited and established on the reefs and the reefs are filtering over 9 million litres or over 3.5 Olympic-sized swimming pools of water an hour!

Check out the latest monitoring results of our Port Stephens project.

The Wagonga Inlet Living Shoreline project at Narooma is kicking many first goals for NSW including the landmark restoration of a subtidal Native Flat Oyster (Ostrea angasi) reef which included a novel 'remote settlement' restoration technique to settle 2 million baby oysters (spat) onto prepared clean shell (cultch).

(1) Beck  et al (2009) Beck MW, Brumbaugh RD, Airoldi L, Carranza A, Coen LD, Crawford Defeo CO, Edgar GJ, Hancock B, Kay M, Lenihan H, Luckenbach MW, Toropova CL and Zhang G (2009). Shellfish Reefs at Risk: A Global Analysis of Problems and Solutions. The Nature Conservancy, Arlington VA. 52 pp.

Lead agency

  • Department of Primary Industries and Regional Development


  • The Nature Conservancy, Australia
  • Eurobodalla Shire Council
  • Nature Coast Marine Group
  • OzFish Unlimited
  • Joonga Land and Water Aboriginal Corporation Divers and Planting team
  • Wagonga Inlet oyster farmers
  • Worimi Knowledge Holders
  • Port Stephens oyster farmers
  • Australian National Maritime Museum
  • Southern Cross University
  • Macquarie University
  • University of NSW
  • University of Sydney
  • Sydney Institute of Marine Science
  • Newcastle University
  • University of Melbourne
  • Port Macquarie Hastings Council
  • Shoalhaven City Council
  • Tweed Shire Council
  • Greater Sydney Local Land Services
  • Hunter Local Land Services
  • North Coast Local Land Services
  • Australian Government
  • OceanWatch Australia

More information

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