The discovery was made as council contractors were preparing to begin their annual Northland-wide hull inspection programme, with more than 2000 hulls scheduled to be checked over the next few months.
Mr McKenzie said the council understood the boat involved had been on a mooring at Tapu Point since early July, and before that had been anchored at Matauwhi Bay. Council records showed it had been inspected at Otiao Bay (Urupukapuka Island) in late 2015, at which time it had some hull fouling, but no marine pests were present.
The council was now organising contractors to survey the mooring area and seafloor where the vessel has been as soon as possible, and would begin the hull inspection programme there.
Last season's survey had found six vessels with fanworms on their hulls at Matauwhi Bay.
"We did a follow-up survey in late July, checking the reef, structures, moorings and adjacent hardstand area where incidents had been recorded, but no fanworms were found," Mr McKenzie said.
Pests did not discriminate when it came to infesting vessels, and last season council contractors had checked the hulls of about 1700 vessels ranging from recreational boats to superyachts, fishing boats and barges. Unfortunately, despite the collective efforts of a range of Northlanders over a number of years, the Mediterranean fanworm was now established in Whangarei Harbour.
"No one wants them spreading any further, and with boat owners [both Northlanders and from other regions] now starting to plan their summer excursions, we want to ensure their vessels are clear of any marine pests before they move to new areas," he added.
For some time now most Northland marinas had been requiring a receipt proving a vessel conformed to the 'six or one' initiative, having been antifouled within six months of leaving a known fanworm-infected area or having undergone a 'lift and wash' within one month of leaving an infected area like Auckland.
However, pests can remain concealed in "niche areas," and be missed during antifouling or cleaning.
The council strongly suggested double-checking areas such as the base of the keel, behind anodes, live bait tanks and bow thrusters before vessels went back in the water.
Depending on what pests were found, owners would be told to haul their vessels out and clean or treat them in what could potentially be a costly process. A $500 fine could also apply.
More information on marine pests can be found at www.nrc.govt.nz/pestcontrolhub, while the council's rules and marina requirements can be found at www.marinepests.co.nz
