Skip to main content

More about Mediterranean Fanworm (Sabella)

On this page: Identifying features, Why fanworm is a risk, How you can help, If you're on the Coromandel, What we're doing to prevent its spread, More information.

report this pest request info


Waikato Regional Council and the Ministry for Primary Industries (MPI) are working together to protect the Coromandel waters you love from Mediterranean fanworm (Sabella spallanzanii).

IMG_7511 fanworm.JPG

Infected hull keel. Photo: Irene Middleton, Northland Regional Council

Report it

If you see this marine pest, call the MPI Pest and Diseases hotline on 0800 80 99 66. If possible, please take photos and record the name of the vessel and where it was moored, or the location if it was found on the sea floor or structures.

Ou biosecurity team is also keen to hear about any unusual marine plants or animals you’ve spotted in Waikato waters, or boats with heavily fouled hulls. Call us on 0800 800 401.

Identifying features

Mediterranean fanworm - also known as Sabella - has become well established in many parts of the Waitemata Harbour and inner Hauraki Gulf, including in marinas, as well as parts of Whangarei Harbour.

It forms dense colonies and has the the following identifying features:

  • A tube, which is generally fixed to a hard surface but can grow in sediment, usually looks muddy and could be up to 60cm long.
  • Long feathery tentacles that look like a single spiral fan and extend out of the top of the tube.
  • A white fan banded with pale fawn, orange or brown.

Why mediterranean fanworm is a risk

Mediterranean fanworm hitchhiked its way to New Zealand on ships from Australia. Make sure it doesn't catch a ride on your boat to your favourite marine destination. If it does, it could:

  • damage your boat by clogging the motor, pipes or propellers
  • increase drag and therefore fuel costs
  • impact on your catch by smothering native species like scallops, paua and mussels
  • affect your enjoyment of activities like diving by changing the underwater character.

How you can help stop its spread

Help us to protect the waters you love by helping to stop the spread of Mediterranean fanworm.

Clean your boat hull twice a year, or before travelling to another region.

Slip and clean your boat Apply antifouling paint Report anything unusual
Mediterranean fanworm can grow from fragments so it’s important that anything scraped off is put in a bin and disposed of at a landfill.  Apply a good coat to your boat and don’t miss those underwater fittings. If you see any unusual marine plants or animals, or boats with heavily fouled hulls, call 0800 80 99 66.
Pay special attention to underwater gear and fitting parts that stick out or retain water like the keel, intakes and outlets, propellers and shafts, rudders and casings.    


Boat hull being cleaned. Photo: Marlborough District Council Apply antifouling paint to your boat.


If your boat has a live bait tank or a bow thruster you'll need to check these. Take a careful look at the sides of the live bait tank as this is a prime location for very small fanworms.

Make sure you dispose of any fanworms you find onto land - they'll keep growing if put back into the sea.

If you're on the Coromandel

To prevent the spread of Mediterranean fanworm, and other marine pests, Coromandel marinas require skippers of visiting vessels to show that they’ve:

  • antifouled their boat hull in the last six months; OR
  • lifted and washed it within the last month.

Please keep receipts of haul outs and/or antifouling.

Even if you don't intend to visit a marina, you may get a spot check from a regional council representative while you're at anchor.

What we're doing to prevent its spread 

Mediterranean fanworm was found inside Coromandel Harbour on the hull of Auckland-based barges in 2013. Waikato Regional Council and the Ministry for Primary Industries (MPI) worked together on the response.

In our 2015-2025 Long Term Plan, our council approved funding to enable us to carry out surveys of our Coromandel harbours and the Firth of Thames to accurately guage the size and scale of the problem to ensure we proactively limit pests spreading. 

We continue to work with MPI to protect the waters you love. 

Logo - Clean below? Good to go

More information

Brochure: Protect the waters you love [PDF, 835 KB]

Ministry for Primary Industries