Mediterranean fanworm

Mediterranean fanworm is a tube-dwelling worm up to 80 centimetres tall. It can form dense beds that compete with native filter-feeding organisms and commercial aquaculture industries.

Description

• Tube-dwelling worm, usually reaching between 10–50 cm but can grow up to 80 cm on occasion.
• Tubes are leathery and flexible with a muddy appearance.
• Prominent spiral crown of feeding tentacles that extend out of the tube.
• The spiral crown is often banded orange or white.
• It can be mistaken for the New Zealand native fanworm. They can be differentiated as the Mediterranean fanworm is larger and has a single fan (rather than the two of the New Zealand species).

Attaches to a wide variety of hard surfaces including rocks, wood, steel, concrete, shellfish and artificial materials, but can also be buried up to 10cm deep in soft substances.

Can be spread on vessels, primarily as hull fouling. However the movement of aquaculture equipment or other marine structures may also contribute to its spread.

What you need to know

Can form dense beds (up to 1000 individuals per square metre) that out-compete other species including competing with native filter-feeding organisms for food and space. They can also clog fishing gear and dredges.

In high densities, Mediterranean fanworm is likely to also impact commercially and culturally important kaimoana species including kuku / kūtai (mussels), tio (oysters), and tipa / tupa (scallops).

The tubes of the Mediterranean fanworm may attach themselves to aquaculture equipment or vessels and this may increase harvesting or fuel costs, respectively.

Management approach

Unwanted organism

An unwanted organism is an organism classified as a pest by the Ministry for Primary Industries (MPI) because it is capable of causing harm to the natural environment, physical resources or human health in Aotearoa/New Zealand.

Rules

Any species declared a pest cannot be sold or be in a place where plants are being sold. Pests cannot be propagated, bred, multiplied, communicated, released, caused to be released, or otherwise spread.

See the MPI website for more information about unwanted organisms.

Control

To help us build a bigger picture of the distribution of Mediterranean fanworms, report any sightings to us. If possible, please take photos and record the location. The location could be the name of a vessel and where it was moored, or the physical location if it was found on the sea floor or structures.

Protect Canterbury's beautiful waterways and marine ecosystems by keeping a clean hull.

Limiting the fouling on your hull stops pests from catching a ride with you into uncontaminated areas or transferring from your vessel to others when moored or berthed in a marina. Keeping your vessel in good shape will also improve its fuel economy and speed.

Check out our handy guide to good boat maintenance practices.

For more information on Mediterranean fanworm and other invasive marine species, visit Marine Biosecurity Porthole.