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Assessing the ecological recovery of shellfish reefs following restoration in southern Australia

Published Article

Australia, South Australia, Western Australia

Publication date: July 17, 2025

File format: URL

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Shellfish reefs are among the most degraded coastal habitats in southern Australia, but large‑scale restoration began in the mid‑2010s. This study reports ecological outcomes from 22.7 ha of restored Ostrea angasi and Mytilus galloprovincialis reefs across Victoria, South Australia and Western Australia between 2017 and 2020. Monitoring shows increasing shellfish density and size, along with the development of diverse associated communities including fish, mobile invertebrates and epifauna. Several species of commercial and recreational interest, such as pink snapper (Chrysophrys auratus), were prominent. These early results demonstrate clear progress toward restoration benchmarks and highlight the potential for rebuilding endangered shellfish reef ecosystems at scale.

Subject Tags

  • Biodiversity
  • Habitat restoration
  • Reefs

Abstract

Shellfish reefs are among the most degraded of all coastal habitats due mainly to historical wild commercial harvest, sedimentation, introduced species, and disease. Until the 20th century, most estuaries and bays across southern Australia contained shellfish reefs. Efforts to restore these endangered ecosystems commenced in the mid-2010s. This study reports ecological responses to some of the first restored shellfish reefs in southern Australia comprising Ostrea angasi (native flat oysters) and Mytilus galloprovincialis (blue mussels). Here we report the methods used to restore 22.7 ha of shellfish reef area (restoration footprint of 18,027 m2) at locations in Victoria (Port Phillip Bay), South Australia (Gulf St Vincent), Western Australia (Oyster Harbour) and provide an overview of the ecological trajectory and biodiversity outputs from the restoration areas compared to control sites across the period 2017–2020. We document progress toward restoration benchmarks for shellfish, fish, and species richness metrics. The early results of these restoration efforts demonstrate progression toward restoration targets due to increasing shellfish density and size, as well as the development of the associated ecological community, including fish, mobile invertebrates, and epifauna. Finally, we identify the predominant species in the associated faunal community, including species of commercial or recreational interest such as Chrysophrys auratus (pink snapper).

Citation

Bayraktarov, E., Rullens, V., Sandry, B., Valesini, F., Fitzsimons, J. A., Branigan, S., ... & Reeves, S. E. (2025). Assessing the ecological recovery of shellfish reefs following restoration in southern Australia. Restoration Ecology, 33(7), e70115. https://doi.org/10.1111/rec.70115

TNC Authors

  • Elisa Bayraktarov
    Data and Science Director, Australia
    The Nature Conservancy
    Email: e.bayraktarov@tnc.org

  • Vera Rullens
    Geospatial Information Coordinator, Australia
    The Nature Conservancy
    Email: vera.rullens@tnc.org

  • Brenten Sandry
    The Nature Conservancy

  • Fiona Valesini
    The Nature Conservancy

TNC Authors

  • James A. Fitzsimons
    Senior Advisor, Global Protection Strategies
    The Nature Conservancy
    Email: jfitzsimons@tnc.org

  • Simon Branigan
    The Nature Conservancy

  • Anita Thomas
    Conservation Coordinator, Australia
    The Nature Conservancy
    Email: anita.thomas@tnc.org

  • Boze Hancock
    Senior Marine Restoration Scientist, Massachusetts
    The Nature Conservancy
    Email: bhancock@tnc.org