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 and in a number of locations in the wider Waitamata Harbour in Auckland.

If you suspect you have found this pest anywhere else in New Zealand (apart from Lyttelton and the Waitemata) 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

When this fanworm species (Sabella spallanzanii) was detected in Lyttelton Port in May 2008, MAFBNZ embarked on a $3.6 million five-year local programme to attempt local elimination of the pest.

The elimination work programme involved ongoing control of the fanworm by diver search and removal and regular monitoring to detect any hidden populations. A communications programme was also undertaken to encourage the owners of moored vessels to keep their boat hulls clean to avoid spreading the pest.

In 2009 the elimination programme was extended to treat what was thought to be a small population of the fanworm in Auckland's Viaduct Basin. In January 2010, the worm was, however, found in large numbers throughout the wider Waitemata Harbour. Consequently in June 2010 a decision was made to cease the elimination programme as, given the wide spread of the population, it was no longer considered feasible to eliminate the fanworm from New Zealand.

Further information on this decision is at: http://www.biosecurity.govt.nz/media/14-06-10/fanworm-response-close