Mediterranean fanworm
| Common name: | Mediterranean fanworm, sabella |
| Scientific name: | Sabella spallanzanii |
| Management programme: | Unwanted organism |
Report this pest!
If you think you have seen this pest, we need to know. Please report it.
Mediterranean fanworms can form dense beds of up to 1000 individuals per square metre. They can outcompete native species, including filter-feeding organisms, for food and space. They can also threaten commercially and culturally important kaimoana species, such as kuku/kūtai (mussels), tio (oysters) and tipa/tupa (scallops).
Fanworms spread by attaching to vessels (fouling) or equipment used for underwater farming. This also increases harvesting and fuel costs, clogs fishing gear and dredges, and impacts fishing operations.
The Mediterranean fanworm is native to the Mediterranean Sea and parts of the North-Eastern Atlantic coast.
The Mediterranean fanworm was first detected in 2008 in Lyttelton Harbour, where it is now well established. Since then, it has spread around the country, and has been detected in Otago and Bluff Harbours.
We are working to prevent the establishment of Mediterranean fanworm in Otago and help prevent its spread into pristine environments and neighbouring areas such as Fiordland.
- Size: This tube-dwelling worm usually reaches between 10–50 centimetres but can grow up to 80 centimetres on occasion.
- Appearance: Tubes are leathery and flexible with a muddy appearance. A prominent spiral crown of feeding tentacles extend out of the tube.
- Distinctive features: A single large spiral of feeding tentacles, often banded in bright colours, such as orange, purple or white.
- Similar species: It can often be mistaken for similar-looking native species; however, native sabellid and serpulid tubeworms are smaller (<20 centimetres) and have two fans. For more information, visit this identification guide from marinebiosecurity.niwa.co.nz.
- Habitat: It attaches to a wide variety of hard surfaces, including rocks, wood, steel, concrete, shellfish and artificial materials, but can also be buried up to 10 centimetres deep in soft substances.
Late summer to autumn (February to April). During this period, Mediterranean fanworms are easier to spot due to their extended feeding plumes. Warmer temperatures often encourage growth and reproduction, increasing their presence.
It is an offence to breed, knowingly communicate, exhibit, multiply, propagate, release, or sell, an unwanted organism (Biosecurity Act 1993).
ORC is currently developing a marine biosecurity programme and needs to obtain more information on species distributions before pursuing management options.
If you think you have spotted Mediterranean fanworm, please let us know.
Report this pest!
If you think you have seen this pest, we need to know. Please report it.
Preventing the spread of Mediterranean fanworm is the best strategy, as removal of invasive marine pests is both difficult and expensive.
Cleaning your craft and gear for biosecurity purposes is an important way to help protect the marine environment. Just as regular maintenance keeps your equipment in good condition, biosecurity cleaning keeps the ocean healthy for everyone.
The three main types of marine biosecurity cleaning for boaties are:
Unwanted organism
An unwanted organism is not managed under the ORC Pest Plan but may be controlled as part of our Biosecurity Strategy.
Protect our Paradise
Do you know what’s lurking beneath your boat? The ORC Biosecurity team works hard to stop harmful pests from spreading in Otago’s coastline and helps people learn how to keep these pests out.
November 2019
PDF | 5 MB
The Otago Regional Pest Management Plan focuses on dealing with harmful pests that impact our environment, economy, and communities. It identifies species like rabbits, wallabies, gorse, and wilding conifers that cause problems on our land. Guided by the Biosecurity Act 1993, the plan works with stakeholders to set rules and controls for managing pests. Through consultation, it aims to protect our region's unique ecosystems and species from the damage caused by these invasive organisms.
November 2025
PDF | 412 KB
Mediterranean fanworms can form dense beds of up to 1000 individuals per square metre. They can outcompete native species, including filter-feeding organisms, for food and space. They can also threaten commercially and culturally important kaimoana species, such as kuku/kūtai (mussels), tio (oysters) and tipa/tupa (scallops).
www.orc.govt.nz/fanworm
