A dozen specimens of the invasive Mediterranean fanworm have been found in the Port Nelson marina, prompting the Nelson City Council to ask boat owners to be vigilant and careful.
The fanworm, which can quickly form big masses and poses a threat to marine farming, was first spotted on May 3 on the hull of the Chatham Islands Shipping Co vessel Manini as it was being made ready for slipway work. It was considered too small to breed, and disposed of.
A council release today says an initial survey at the beginning of November found one immature specimen under a pontoon at the marina.
A more exhaustive search was commissioned in partnership with the Ministry for Primary Industries, and another 11 worms were found.
"The good news is that none of the specimens showed signs of being able to reproduce," said council communications manager Angela Ricker.
The fanworm, which is thought to have arrived in New Zealand from Australia, is rampant in Auckland's Waitemata Harbour and is also present in Whangarei, Lyttelton and the Coromandel.
Ms Ricker said recreational boaties were being asked to pay particular attention to cleaning and antifouling their boats before leaving Nelson for the summer holidays.
The owners of commercial vessels were also being asked to ensure that their vessels were regularly maintained, with good, effective antifouling in place.
The fanworm (Sabella spallanzanii), one of the six unwanted marine organisms on the national priority list, can smother native marine species and alter underwater ecosystems.
It was first found at Lyttelton in 2008, and biosecurity officials have said it is too well established here to be eradicated.
It anchors a tube up to 40 centimetres long to a hard surface, with a spreading fan emerging from the top.
❏ Suspected unwanted organisms should be reported to MPI's exotic disease and pest hotline, 0800 80 99 66.
Information on stopping the spread of marine pests is under marine cleaning at www.biosecurity.govt.nz.
- © Fairfax NZ News
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