The invasive species that produce 70,000 offspring a year – each

Scientists are calling it an invasion.

In parts of the Waikato River, gold clam clusters int 3000 individuals per square metre. Now they've just been detected in another New Zealand waterway.

Gold clams – originating in east Asia – were first discovered at Bob's Landing near Cambridge in May 2023.

The clams clog both irrigation systems and water treatment plants, they also compete for food with native species such as freshwater mussels.

"[They] can strip out a lot of the nutrients from our waterways, which our native species need to also grow and thrive," said Michele Melchior, a freshwater ecologist from Earth Sciences NZ.

The clams posed an especially critical issue at present, as scientists believed we're in their breeding season.

With one clam able to produce 70,000 babies a year, the speed at which they've spread was not surprising.

Now scientists wee attempting to stop the invasion – and called on the public for help.

"New Zealanders can all do their part in terms of keeping their gear clean, making sure that it's dry before they go from one waterway to another, then everybody can play a really important role in keeping the invasive species where it is," said Dr Deborah Hofstra, a freshwater scientist with Earth Sciences.

The clams were recently detected in Lake Rotomanu in Taranaki, marking the species' first identification outside of the Waikato River.

The body of water was drained in response, but the focus wasnow on preventing outbreaks in other parts of the country.

One Waikato University incentive aimed at their prevention has employed dogs Lily and Chino, which are being trained to sniff out the clams at public water entryways.

Researcher Lucy Tannahill explains: "The idea is to get them down at boat ramps, searching vehicles and things that are about to enter the water. So they're kind of like a last line of defence before a vehicle or a boat that's got clams on it enters the water and then potentially infects it."

The protection of native shellfish species comes down to humans and dogs because once the clams are in – eradication is nearly impossible.