The caulerpa dredge in the Bay of Islands collects up to 250 tonnes at a time. Photo: Supplied / Rana Rewha
The government is putting another $10 million towards new tools aimed at removing invasive seaweed caulerpa from New Zealand's waters.
Described as the world's worst marine pest and the "cancer of the sea", exotic caulerpa spreads rapidly and smothers other species, threatening fish and shellfish populations.
It is increasingly invading New Zealand's waters, spreading off Aotea Great Barrier, Waiheke Island, a reef near Kawau Island, and thick infestations at Rāwhiti in the Bay of Islands.
Other countries have been unsuccessful in trying to control or eradicate the pest.
In a statement on Wednesday morning, Biosecurity Minister Andrew Hoggard said the funding would go to projects like the dredging project in Northland.
"The $3.3 million large-scale mechanical suction dredging project in in Omakiwi Cove in Northland made some significant advances but found that achieving fast and cost-effective removal is still challenging and further research and development is required," Hoggard said.
The locally designed and built dredge is like an underwater vacuum with a nozzle the size of a small car, which in minutes sucks as much caulerpa off the seafloor as a diver could in a day.
Hoggard said other projects included cameras which could be mounted on boats or towed and use AI to locate the weed in real time, and campaigns to teach communities not to spread it.
"We know affected communities want to continue the battle against this challenging problem and there have been some promising technology developments that we would like to push further," he said.
"This additional $10 million will keep the momentum going in improving the technology and tools that we have identified and will also be used to help slow the spread."
"We are also aware of other promising technology developments that have been self-initiated by iwi, communities, scientists and others. All this effort needs to be built on and, while we have a seriously difficult problem with exotic caulerpa, there is some cause for optimism."
The new funding brings government support to $15m, well shy of the $100m Northland Regional Council last month said was needed.
Hoggard said a National Advisory Group aimed at tackling the pest had also been set up, and would work with biosecurity officials to help prioritise the funding allocation and work on other options for tackling caulerpa.