Oversized, underwater vacuums are being trialled on the Hauraki Gulf seabed as a way of eradicating the aggressive seaweed, caulerpa, that smothers everything in its path.
But some question whether the Ministry for Primary Industries (MPI) is doing enough, fast enough, to see it off as a serious threat to New Zealand's marine life.
A vacuum with a difference. It's what the government hopes will help save the Hauraki Gulf and beyond by sucking up the introduced pest weed, caulerpa.
"Underneath the waters, we have an invasive predator that absolutely places at risk the marine life and all that we know," said Ngāti Manuhiri CEO Nicola MacDonald.
The destructive weed was first detected at Aotea/Great Barrier in 2021 but since then, it's spread fast to Great Mercury Island, Waiheke and Kawau Islands and it's now been found outside the Hauraki Gulf - at Te Rāwhiti Inlet in the Bay of Islands.
It may look fairly innocuous but a Hauraki Gulf Forum report says once caulerpa spreads it can reduce fish stocks by 30 to 50 percent.
"We've got to do something, and it's absolutely about action, the times of studying caulerpa are over," MacDonald said.
The suction dredge trial started on Monday at Aotea, Great Barrier Island. Divers have been able to clear around a tonne of caulerpa from a 60 square metre area per hour. It's estimated over 10 tonnes will be removed by next Wednesday.
"And also, as part of that, then also trialling on those areas that have been suction-dredged putting mats down with chlorine treatment underneath to see how effective that is at controlling it and stopping it coming back," said Biosecurity New Zealand's deputy-director general Stuart Anderson.
The weed was first discovered two years ago, and there's no exact timeline for the full removal of the weed. Some question whether MPI is doing enough, fast enough.
"We're not moving fast enough at all, actually. I'm wanting the Crown, the Government, to fully invest, remove some of the restrictions around getting into the water, allow and support communities who have qualified commercial divers to assist NIWA, to assist MPI, so we can get on with the job," MacDonald said.
MacDonald wants more community divers, with commercial qualifications, in the water removing the weed, now.
MPI said it's taking the threat seriously, and a lot of work has been done.
"It is a difficult, challenging pest, in the marine environment, it's been difficult overseas but we are committed to working with everyone," Anderson said.
Hoovering up what would otherwise smother everything in its path.
