Marine Pests

While you are out beachcombing, you can help protect WA by keeping an eye out for marine pests which are marine plants or animals that could be introduced to the State. They are a significant threat to global biodiversity and can damage the economy, environment, social amenity and human health.

Once well-established, marine pests are virtually impossible to eradicate. To increase the chances of a quick response and successful removal of marine pests, early detection is essential. Being aware of marine pests – we’ve added four (green mussels, European shore crab, Japanese kelp/Wakame and Northern Pacific seastar) to this guide but there are others – and reporting anything new and unusual is a great way to help protect WA.

If you think you have found or seen a marine pest: 

1. Photograph it – from different angles, e.g. top, bottom, etc. Place an object for scale, or a ruler if possible, next to the specimen and photos of the location where you found it.

2. Record it – size, colour, depth and how and where it was found, using GPS readings if available. Otherwise describe the area in which it was found in as much detail as possible.

3. Collect it – collect a sample in a plastic bag and refrigerate it or keep it on ice but do not freeze it.

4. Report it – contact the FISHWATCH 24 hour hotline on 1800 815 507, or use the free WA PestWatch app. – links below (NOTE: If you collect samples please report it to FishWatch immediately).


For more information and how you can help recognise marine pests, visit