Boaties are being urged to check for unwanted hitchhikers before moving between lake and river spots this long weekend - to stop the spread of an invasive freshwater pest.
The gold clam has been found in the Waikato River so MPI has issued guidelines to stop it taking hold in new waterways.
It's manus [dive bombs] only in Lake Ōkataina right now.
Boaties and fishers have been banned for a month to protect this precious roto [lake] from a foreign pest.
"I'm happy with what they're doing," said local resident Ana Te Whata-Jacobs.
"We've got a clam invasion here, so that's what they're here for to make sure that doesn't overtake our beautiful lake of Ōkataina," she told Newshub.
Gold clams have colonised a 99-kilometre stretch of the Waikato River, only discovered in May.
How they got here is still unknown.
They can clog water pipes and hydro dams, and overrun native species.
While they haven't been discovered anywhere else in Aotearoa, they spread easily and multiply by the tens of thousands.
"They've only been in New Zealand, in the Waikato River, for two or three years, so we don't know how bad they could be here," said John Walsh, director of readiness and response services at Biosecurity NZ.
"But overseas they have become quite problematic in a lot of countries," he told Newshub.
Te Moana a Toi / Bay of Plenty iwi Ngāti Tarāwhai asked Biosecurity NZ to close Lake Ōkataina to fishing and boating and even hired security after online threats to drop clams in the lake.
And as we head towards warmer weather, officials have issued a plea to boaties: check, clean and dry.
"So check means have a look at the equipment, the boat, for anything that's visible - whether that's weed, or mud, or clams, or sand, and remove it," Walsh said.
"Clean means wash it down with a high pressure hose," he added.
Experts say it's impossible to eradicate the clam but keeping its numbers down is feasible - if water users chip in to help.
"So if somebody's got even a few drops of water in the bottom of their boat, or on some gear, they take that to another lake, and you could easily spread the clams that way," Walsh said.
Fish & Game says Biosecurity NZ needed to spring into action faster to stop the clams' spread.
"We know that steps have been put in place now, but we're worried about the speed that that's taken and the potential implications of the transmission of the gold clam from the Waikato River to other areas," said Corina Jordan, CEO of Fish & Game.
Because once invaders take hold in precious lakes like Ōkataina, it's too late.
