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Published: 2014-10-30 00:00:00

A new plan to tackle the spread of the dangerous marine pest Mediterranean fanworm into Coromandel harbours and the Firth of Thames has today been endorsed by Waikato regional councillors at their meeting in Hamilton.

Council staff will now develop a small-scale management programme under the Biosecurity Act which will encourage boaties coming into Waikato waters to clean their hulls regularly. The primary way fanworms are spread is when they are carried on boat hulls.

“Mediterranean fanworm or sabella, officially categorised as an unwanted organism in New Zealand,is a nasty pest which has become well-established in Auckland’s Waitemata harbour and is found in other parts of the country as well,” said animal pest team leader Dave Hodges.

“It has also been detected in Coromandel harbour twice in recent years. Given fanworm’s ability to crowd out shellfish in harbours and in mussel farms, we want to keep it from getting well-established in Waikato waters, particularly the Coromandel coast and the Firth of Thames, so as to protect our $50 million a year mussel and oyster farming industry in the region.

“A small-scale management programme will help us encourage boaties to make sure they undertake usual routine maintenance on their hulls, and gives us the basis to recover costs if we have to step in and clear up fanworm outbreaks they are responsible for.”

Mr Hodges said it was intended to have the new measures in place by February next year. Education about the new rule requiring regular hull clearance if using the Firth or Coromandel harbours will be undertaken before then.

The council’s agreement today to the new small-scale management programme follows an incursion of the fanworm into Coromandel harbour last year which to date has cost about $100,000 to clear up. The council was unable to recover costs from the owner of the two barges from Auckland that are believed to have brought in the fanworm that got established then.

Currently, a $70,000 a year fanworm monitoring and control programme is in place, co-funded by the council and the Ministry for Primary Industries.

A staff report to today’s meeting said it was believed the risk of another incursion being detected was “extremely high due to the high number of vessels moored in the harbour with varying states of hull fouling, our proximity to the heavily infested Waitemata Harbour and the popularity of the Coromandel Peninsula for recreational boat users travelling to and from the Waitemata”.

By having boaties regularly clean their hulls, any fanworm on them should not be able to grow to breeding size, the report said.

“Vessel owners can easily comply with this rule if they adhere to reasonable maintenance regimes for their vessel which include regular hull antifouling treatments,” it added. For most recreational vessels costs varied between $500 and $2000 depending on who carried out the work. Mr Hodges said it was likely cleaning would be required once every one to two years.

Owners of structures such as moorings and wharves will also be required to keep them clear of sabella under the new rules. It was expected these costs would be relatively low as fanworm in the Waikato region has only been detected in Coromandel harbour to date and numbers are very low.

Voluntary compliance with the rules was anticipated in the majority of cases but the new plan would give the council power to enforce rules when this is not the case, the report said.