1. Marine Pests
  2. Marine pests
  3. Identify
  4. American slipper limpet

American slipper limpet


American slipper limpet (Crepidula fornicata)

Not established in Australia

Features: Large internal aperture with a shelf extending half its length. Smooth oval-shaped shell. White, yellow or pink streaked. Irregular growth lines. Up to 5cm long.
Habitat: Shallow estuaries and coastal bays.
Affects: Native species, aquaculture.
Movement: Vessels, translocation with oysters.

American slipper limpet (Crepidula fornicata) competes with native species for food and space. It may alter sediment characteristics by removing suspended sediments from the water column.

What to look for


  • shell is white, yellow or pink with red-brown streaks
  • large internal aperture with a shelf extending half its length
  • oval-shaped smooth shell
  • irregular growth lines
  • may be found in stacks
  • up to 5cm long.

Where to look

Look in or around:

  • mud
  • rocks
  • sand.

Likely habitats include:

  • shores and shallow waters.

Similar native species

These native species look similar to American slipper limpet. They do not need to be reported.

Expand all

Northern slipper shell (Bostrycapulus pritzkeri)


  • brown and white shell
  • spines or bumps on shell
  • up to 3cm long.


  • attached to other shells
  • mangroves
  • mud
  • rocks
  • sand
  • shores and shallow waters.

Known locations are from Shark Bay in Western Australia around northern Australia to south–east Victoria.

Notoacmea mayi


  • light brown to grey with mottled bands
  • no internal shelf of shell
  • up to 1.5cm long.


  • hard surfaces in upper shores.

Known locations are New South Wales, Victoria, Tasmania, and eastern South Australia.

Nerita polita


  • white, cream, grey or pink shell
  • smooth glossy-shell with fine growth lines
  • marbled, streaked or banded patterns on shell
  • up to 3cm long.


  • often buries in sand
  • surfaces at low tide to feed, on rocks.

Known locations are from the North West Cape of Western Australia to Sydney, New South Wales.

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 (screenshot your map app or enable photo geotagging on your phone)​
  • 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:

  • Check anchors and other equipment for tangled algae.
  • 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.