Invasive fanworm discovered
The flower-like heads of Sabella spallanzanii from Lyttelton Port. When fully-spread in life, each fan is neatly spiralled. (Photo: Geoff Read, NIWA)
When NIWA taxonomist Geoff Read slit open a leathery marine fanworm tube from a March port surveillance sample, he knew immediately the worm hidden inside was not a native. Close examination of the specimen collected from a wharf pile in Lyttelton by NIWA’s dive team confirmed that the invasive pest, Sabella spallanzanii, had reached New Zealand.
The flower-like Mediterranean fanworm S. spallanzanii is one of eight unwanted marine species targeted in MAF Biosecurity New Zealand’s port surveillance programme. So far, only eight further specimens have been collected from Lyttelton Port in subsequent surveys carried out by NIWA and the Cawthron Institute. These were distinguished from native tube-dwelling fanworm species by Dr Read.
S. spallanzanii can build tubes longer than 30 cm, carpeting pontoons, piles, hulls, floats, and ropes, as well as spreading over the seabed. It is a space-occupier, crowding out other species, and may compete with native species for food as well as space. The worm may not yet be established and breeding in the murky Lyttelton waters. NIWA is now coordinating a further search of the known infested area for MAF Biosecurity New Zealand. Divers will remove any Sabella specimens they find.