Divers to inspect boat hulls for pests at popular holiday spots

The number of boat hulls checked for marine pests will almost quadruple in Northland this summer with local authority divers poised to inspect about 1500 vessels at popular holiday spots.

Northland Regional Council Chairman Bill Shepherd says as well as a big increase in hull inspections (about 400 were done last summer) the region's marinas are also playing their part in the war on marine nasties and are now insisting on tougher entry criteria.

Dive contractors Vince Kerr and Associates will have a four-strong team checking vessels for a range of marine pest animals and plants including Mediterranean fanworm, the sea squirt styela clava and the seaweed undaria.

Councillor Shepherd says depending on the pests found, owners will be asked to haul the vessels out and clean or treat them in what can potentially be a costly process.

"As well as reducing the risks from a biosecurity perspective, it also makes good financial sense to check your vessel carefully before heading to Northland."

He says other parts of New Zealand, including Auckland, have established populations of unwanted pests like Mediterranean fanworm and the council's usual message for boaties to check their hulls before venturing north remains.

Councillor Shepherd says Northland's marina operators have come up with a plan to protect their own assets from marine pests and now require evidence of a clean hull before they will allow entry.

"Operators will need to see a receipt proving a vessel conforms to what's been dubbed the 'six or one' initiative; being either 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, some vessels that have adhered to the recommended 'six or one' messaging have still encountered issues with fanworm surviving in 'niche' areas anti-foul has not reached.

"Marine pests can be concealed in these niche areas and can easily be missed during antifouling or cleaning. We strongly suggest you double check areas like the base of the keel, behind anodes, and the bow thrusters before your vessel goes back in the water."

Councillor Shepherd says in recent months council staff have found fanworm in previously uninfected areas including Tutukaka, Whangaroa Harbour and Parua Bay, reinforcing the need for extra vigilance and reporting even for local, Northland-based vessels.

However, there has been some good news too; a newly discovered fanworm population in Tutukaka was caught early before it had a chance to become well-established and Marsden Cove Marina had reduced fanworm in its main marina to a level where it is no longer consider a risk to vessels berthed there.

"We encourage people to be our eyes on the water and report any sightings of fanworm or other unusual marine pests to either the Ministry for Primary Industries via its free hotline (0800) 809 966 or by emailing our own biosecurity experts at [email protected]

As well as the dive contractors inspecting boat hulls, regional council staff are also back out on the water again, talking with vessel owners and making sure they are aware of Northland's marine biosecurity and pollution rules.

Councillor Shepherd says staff are happy to chat to boat owners or other members of the public and answer any questions they may have.

Meanwhile, he says general information on marine pests can be found at www.biosecurity.govt.nz