Mediterranean fanworm

Sabella spallanzanii

Legal Status: Unwanted Organism - MFish

Status in New Zealand: Established

Organism: Water snails, crabs, shellfish, starfish, and other aquatic

This pest is an unwanted organism and is present in New Zealand. It has been detected in Lyttelton Port where a programme is underway to attempt to eliminate it. A single specimen of the fanworm was detected in August 2009 near the entrance to Auckland's Viaduct Basin. MAFBNZ is currently assessing its response to this latest find.

If you suspect you have found this pest anywhere else in New Zealand, including other locations in Auckland, please call 0800 80 99 66.

If you are the owner/operator of a moored boat, you can help prevent the spread of this marine pest by ensuring your boat's hull is clean and well antifouled.

Mediterranean Fanworm
Lyttelton fanworm out of its tube.
Photo: G. Read, NIWA

Description

The Mediterranean fanworm is a marine animal that is typically found in estuaries or sheltered sites, found at depths of anywhere between one to 30 metres.

It consists of a tube which is always anchored to a hard surface, topped with a single spiral fan (radiole). The tube is tough and flexible and often muddy in appearance. It can often have other organisms growing on the surface.

Mediterranean fanworms grow up to 40 cm tall. The fans are white, banded with brown and orange, and the central stem is orange.

This particular fanworm looks different to New Zealand native fanworms in that it is larger and it has the single fan. Fanworms with two spiral fans are NOT this pest.

Impact

The Mediterranean fanworm (Sabella spallanzanii) can form dense groups that could affect native species by competing for food and space. Recent studies have indicated some impact on the establishment of new generations of some species, and on nutrient flow.

The presence of dense mats of this species could also have an impact on the aesthetics of an area for diving, potentially impacting on dive tourism activities.

While they have not yet been recorded to have had significant impacts on fisheries or aquaculture, there is potential that dense beds could become a nuisance to recreational and commercial fishers through the clogging of dredges and fouling of other fishing gear.

MAFBNZ programme to eliminate Mediterranean fanworm in Lyttelton Port

MAFBNZ has embarked on a $3.6 million five-year local programme to rid Lyttelton Port of the marine pest Mediterranean fanworm.

The fanworm (Sabella spallanzanii) was detected in the port in May through the Ministry of Agriculture and Forestry's targeted marine pest surveillance programme.

Since then, MAFBNZ has carried out interim measures such as thorough surveillance and a diver search and removal operation. Research has shown this method to be the only effective way to treat the pest. Information obtained from these measures indicates that the incursion is relatively recent and appears to be confined to Lyttelton Port.

The elimination work programme will involve ongoing control of the fanworm by diver search and removal and regular monitoring to detect populations. There will also be a communications programme to encourage the owners of moored vessels in the area to keep their boat hulls clean to avoid spreading the pest.