Getting to know the Mediterranean fanworm


Top of the North Marine Biosecurity Partnership

The notorious Mediterranean fanworm, Sabella spallanzanii, first appeared in New Zealand in March 2008 in Lyttelton Harbour. Despite intensive efforts to restrict its spread, it’s managed to spread throughout much of the Waitemata Harbour, as well as Whangarei and Coromandel harbours. It’s also been detected in a few other locations where the local efforts to get rid of it appear to be successful.

The Mediterranean fanworm has the potential to be a major nuisance for aquaculture in New Zealand, since it’s highly adaptable and can grow directly on the outer shell of cultured shellfish, such as mussels and oysters.

The Mediterranean fanworm. Photo credit: S Wilkens

To come up with a plan of action to get rid of this pest, it’s important to find out more about its basic biology and how it lives in New Zealand conditions, especially in the context of mussel farms.

To that end, a PhD research project has been co-funded by the Ministry for Primary Industries, Coromandel Marine Farmers Association, University of Auckland, and a coalition of regional councils from the Top of the North Marine Biosecurity Partnership.

“We’ll be looking at the settlement, growth and reproductive behaviour of fanworm in the context of Greenshell mussel farms in the Coromandel area,” says Sarah Brand, student researcher. “That includes a close look at what seasons the worm reproduces in, how the larvae grow and whether these worms can survive after being damaged during mussel harvesting.”

Mediterranean fanworm attached to mussels at a mussel farm. Photo credit: K Walls
MedFanwormLab v2
Student researcher, Sarah Brand in the lab getting up close and personal with a Mediterranean Fanworm

"Back at the lab we’re developing methods for artificially inducing spawning and raising the larvae of fanworms so we can observe their development and behaviour first hand,” Sarah explains “We’re using some new methods to detect microscopic larvae in water samples and on settlement surfaces deployed at the mussel farms.”

Sarah says she’s already finding major differences in the biology of fanworm living in New Zealand compared to reports of those overseas. She hopes the knowledge gained through her studies will help to manage fanworm in aquaculture, and in the control of fanworm more widely around New Zealand.