Biosecurity Spotters logo

Asian clam (Corbicula fluminea)

The Asian clam is an invasive freshwater species detected along the Brisbane River in Queensland, and it could become a major pest in Western Australia. Its rapid growth and reproduction can allow it to spread and cause ecological and infrastructure problems.

Key facts

Type: Pest animal, invertebrate.

Native to: Eastern and southern Asia.

Established in: QLD, NSW.

Other names: Freshwater gold clam, Asiatic clam, Golden clam.

Best time to act: Inspect year-round, paying particular attention to accessible shallow areas, and coordinate any control work with the relevant biosecurity agency.

Identification

  • The shell has distinct, evenly spaced concentric ridges and may reach 50 to 65 mm long, although it is usually less than 25 mm.
  • Juvenile shells are oval, while adult shells become more triangular.
  • Shell colour ranges from yellow-green or light brown to olive-green or black.
  • The outer shell layer can flake off to reveal a white layer underneath.
  • The shell has three cardinal teeth and serrated, rather than smooth, anterior and posterior lateral teeth.
  • Look-alike: Native freshwater clams may look similar; the Asian clam's concentric ridges, shell shape and serrated lateral teeth help distinguish it.

Where it lives

In Australia it occurs in freshwater environments, including the Brisbane River, and can colonise a range of river habitats.

Why it matters

  • It can displace native clams.
  • Dense populations can diminish water quality.
  • Clams can block pipes and damage water infrastructure.
  • Its rapid growth and high reproductive rate can help it colonise a wide range of habitats.

How it spreads

  • It can be transported between locations in ballast water or through the aquarium trade.
  • Its larvae can be carried over large areas by river flows.
  • Boats and fishing equipment may pose a risk of moving aquatic pests between waterways.

Control methods

  • Do not move live clams, water, sediment or contaminated equipment from an infested site to another waterway.
  • For localised infestations, seek advice from the relevant state or territory biosecurity agency before attempting physical removal, and contain removed clams and material so they cannot return to the water.
  • Use only control methods approved for the waterbody and follow agency advice; do not apply chemicals unless specifically authorised for that use.
  • Recheck treated areas for surviving or newly settled clams, and report suspected sightings promptly to the relevant biosecurity agency.

Site hygiene and welfare

  • Clean boat hulls, fishing equipment and other gear on land, and prevent any fouling aquatic life from re-entering the water.
  • Ensure boats and equipment are dry before moving them to another location.
  • Use methods set out in the national model codes of practice and standard operating procedures for the species.
  • Coordinate control with neighbours and the local government biosecurity plan, as isolated effort is quickly undone by reinvasion.

Classification by state

  • Australia (national): National priority exotic pest. On the National Priority List of Exotic Environmental Pests, Weeds and Diseases, so any new detection should be reported straight away.
  • Queensland: Restricted matter, categories 2, 3, 4, 5. Report it to Biosecurity Queensland within 24 hours; do not give it away, sell or release it into the environment; do not move it; do not keep it. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Prohibited matter. It is an offence to deal with it, and you must notify NSW DPIRD as soon as you become aware of it.
  • Victoria: Noxious aquatic species. Declared a noxious aquatic species under the Fisheries Act 1995, so it must not be brought into Victoria, kept, sold, moved or released into waters. Report any sighting to the Victorian Fisheries Authority on 13 FISH (13 3474).
  • South Australia: Not declared. Not declared under the Landscape South Australia Act 2019. Other laws may still apply.
  • Western Australia: Noxious fish. Prescribed as a noxious fish under the Fish Resources Management Regulations 1995, so it must not be brought into WA, kept, sold or released. Report any sighting to FishWatch on 1800 815 507.
  • Tasmania: Not a declared pest. Not a declared pest or prohibited matter in Tasmania. Importing animals is still controlled by Biosecurity Tasmania.
  • Northern Territory: Not a declared pest. Not on an NT declared or prohibited list. Check with the NT Government before keeping, moving or releasing it.
  • Australian Capital Territory: Not declared. Not declared under the Biosecurity Act 2023 (ACT). A general biosecurity duty still applies.

Legal obligations

Every state and territory places a duty on landholders and people working on land to prevent the spread of invasive species, such as the general biosecurity obligation in Queensland and the general biosecurity duty in New South Wales. Declarations and control requirements differ between states and local government areas, so check the current official list before work starts.

  • Queensland: Biosecurity Act 2014 (Qld), administered by Biosecurity Queensland (13 25 23)
  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development

Sources