Brown mussel

Body contents

Brown mussel (Perna perna) is a fast growing pest that competes with native species. It fouls navigation buoys, petroleum platforms, wrecks, jetties and other hard surfaces.

This pest can accumulate heavy metals and toxins, causing shellfish poisoning if eaten by humans.

What to look for


  • dark brown
  • smooth with evenly-spaced growth lines
  • straight and proportionally long hinge
  • thin at edges and thickens towards narrow end
  • around 9cm long, but can be 5cm to 17cm long
  • forms dense groups.
Brown mussel
Photo Evan Rees, Department of Agriculture and Water Resources

Where to look

Look on or around:

  • buoys
  • mangroves
  • other shells
  • piers and wooden structures
  • rocks and stones.

Likely habitats include:

  • hard surfaces, but may form aggregations on soft surfaces
  • shores and shallow waters.

Similar native species

These native species look similar to Brown mussel. It does not need to be reported.

Hairy mussel (Trichomya hirsuta)

Missing media item.


  • shell covered in short bristles
  • external radial ribs
  • internal shell is smooth and bright (mother of pearl)
  • forms clumps
  • up to 6cm long.


  • attached to each other or rocks on sea floor
  • in intertidal or shallow subtidal areas.


Report it

See something unusual? Report it. Even if you’re not sure.

If you see something you think is a pest:

  • note the exact location
  • take a photo (use something for size reference, like a coin or note)
  • contact your state or territory authority.


Stop the spread of marine pests

Start with these simple steps:

  • Inspect and clean your boat or yacht. Make sure you check hard to reach areas.
  • Treat the hull of your boat or yacht regularly.
  • Clean and dry your fishing and diving gear after every use.

How you can stop the spread of marine pests.

Your location

Check our marine pests map.

The map shows known pests and pests to look for around Australia.

Brown mussel

Brown mussel (Perna perna)

Not established in Australia

Features: Dark brown. Smooth shell with concentric growth lines. Thin at edges of shell. 5cm to 17cm long.
Habitat: Intertidal and subtidal, primarily hard substrates
Affects: Native species, buoys, seawater cooling pipeswater intakes, and human health.
Movement: Vessels.