Brown mussel


Have you seen brown mussel?

Be on the lookout for brown mussel and report it to Biosecurity Queensland. Early detection helps protect Queensland's natural marine environment, the businesses that rely upon it and our way of life.

Call us on 13 25 23.

Brown mussel is an invasive and prohibited marine pest not found in Queensland waters. They can be introduced via ship's ballast water, as biofouling on boat hulls and through internal seawater systems.

They grow up to 12cm long and have a smooth shell with concentric growth lines. They are a prolific fouler and can out-compete native species. It is illegal to import, or in any way deal with brown mussel.

You must report any suspected sightings to Biosecurity Queensland.

Scientific name

Perna perna

Similar species

  • Hairy mussel (Trichomya hirsuta)


  • Smooth, dark brown shell with concentric growth lines.
  • Thin at the edges, thicker towards the narrow end.
  • Straight with proportionally long hinge line.
  • Shell is up to 12cm long.
  • Accumulates toxins and heavy metals, which can cause shellfish poisoning if eaten by humans.


  • Hard and soft substrates (dead shells, rocks, piers, stones, buoys)
  • Intertidal and subtidal
  • Prefers areas rich in organic matter and plankton carrying low loads of suspended sediments


  • Not found in Queensland. Native to the tropical and subtropical waters of Africa and introduced to the northwestern Indian Ocean, Gulf of Mexico, Caribbean Sea and southwestern Atlantic Ocean.

Life cycle

  • The mussel uses external fertilisation during the spawning season between May and October, although this is also reported to occur in December.
  • Females release eggs that are fertilised in the water producing veliger larvae.
  • 15 hours after fertilisation the larvae have well-developed hinge teeth.
  • 10–12 days after fertilisation the larvae undergo metamorphosis where byssal threads are secreted where the larvae can then settle on rocky surfaces or attach to a solid surface.

Affected animals

  • Native aquatic animals



  • Fast growing, prolific fouler and out-competes native species.


  • Forms dense colonies that can foul hard and soft surfaces including dead shells, rocks, piers, stones, buoys and mangroves.
  • Can clog seawater cooling pipes and intake systems.


  • Can negatively affect the visual amenity and our way of life. Marine pests can:
    • lead to depleted fish stocks
    • lead to boating and fishing restrictions in affected areas
    • impact significantly on the marine industry that many people rely on for employment and recreational purposes.


Look. Report. Protect.

Marine biosecurity – everyone plays a part.

  • Clean your boat regularly.
  • Check for marine pests on structures and surrounds.
  • Report any suspected marine pests.

Slipway operators, vessel inspectors and vessel owners should regularly and thoroughly check and clean vessel hulls, looking out for pests or growth. Pay particular attention to the nooks and crannies of your vessel including internal seawater systems.

Inspect, clean and dry equipment and gear before moving to a different location. This includes pots, nets, fishing or diving gear, anchors and ropes.

If you think you have seen brown mussel, report it immediately to Biosecurity Queensland on 13 25 23. Until an authorised officer contacts you, please take reasonable and practical steps to prevent it from spreading.

Legal requirements

  • Brown mussel is a prohibited marine animal under the Biosecurity Act 2014.
  • Report any suspected sightings to Biosecurity Queensland on 13 25 23 immediately.
  • Biosecurity is a shared responsibility and by law everyone has a general biosecurity obligation (GBO) to take all reasonable and practical steps to avoid introduction or spread of marine pests.

Further information