A NIWA-led programme to develop effective, and culturally-attuned strategies for managing the freshwater gold clam.
Stopping the spread of the freshwater gold clam (Corbicula fluminea) is of critical importance for preserving native biodiversity, protecting infrastructure, and maintaining the cultural and recreational value of Aotearoa-New Zealand's waters.
Alongside establishing practical control methods, the research programme will determine the gold clam’s ecological, social, cultural and economic impacts in Aotearoa-New Zealand, and predict its spread for early detection and targeted intervention.
This MBIE-funded Endeavour research programme will:
Understand the impacts of the gold clam (ecological, economic, and cultural)
Predict dispersal and future establishment enabling the prioritisation of locations for monitoring and early intervention
Develop a suite of effective interventions (tools) to reduce the risk of transfer and to manage the gold clam at different scales.
Key collaborators include NIWA, Ngaati Koroki Kahukura, Waikato Tainui, Raukawa, University of Waikato, and international experts.
From the field
Deborah Hofstra, ESNZ
Earth Sciences NZ, Taranaki Regional Council and Blake Interns surveying clams by sieving lake substrates (sampled by the team in waders) from Lake Rotomanu following a drawdown, to get a better understanding of the clams abundance. This information that is needed to support the development of the next stage of the response.
Deborah Hofstra, ESNZ
Blake interns Anna and Elenor surveying substrate from Lake Rotomanu alongside the Earth Sciences NZ research team (December 2025).
They’re not lying down on the job; they’re scanning the lakebed for an invader. Earth Sciences NZ ecologists and visiting clam expert from Ireland, Prof. Frances Lucy, at Bob’s Landing on Lake Karāpiro prior to a December 2025 lakeside hui.
Alex Fear, ESNZ
One News filmed an invasive gold clam story after seeing the media release and video. This will run over the Christmas break.
Alex Fear, ESNZ
Researcher Michele Melcheir shows kahui clams and discusses ESNZ research at lakeside hui at Bob’s Landing, Lake Karāpiro. Aso presenting was visiting Irish professor Frances Lucy.
Michele Melchior, ESNZ
Presentation to Karāpiro Lake users group meeting in October of Earth Sciences NZ decontamination research and process.
Blake Interns are working alongside the team on the first of our benthic barrier (control tools) experiments. Here Te Kūwaha Summer Intern Fleur Passau is taking a water sample from dead clams at our Ruakura facility (December 2025).
Brian Smith, ESNZ
MPI Ambassador training at Karāpiro lake 16 November 2025 presentation by Earth Sciences NZ researcher Brian Smith.
ESNZ ecologist Brian Smith presenting at the NZ Freshwater Science Society conference in December 2025.
A dive survey of Lakes Maraetai and Karaapiro was conducted in May 2025. Multiple sites were surveyed as part of the programme aim to assess changes in population structure and spatial spread over time. This survey will be repeated in 2026 and 2027 to understand how the abundance of clams and kaakahi at these different sites changes.
Juvenile gold clams are difficult to detect in aquatic environments due to their small size. To survey gold clam infested environments NIWA are testing Hester-Dendy multi-plate samplers. In March 2025, 16 samplers were deployed at Bob’s Landing, Lake Karāpiro.
International collaboration - Brian Smith (NIWA) and Dr Yu Cao (Wuhan Botanic Gardens, Chinese Academy of Science) examining the clams at the lakeside clam hui.
Elizabeth Graham (NIWA) identifies clam species during a Corbicula fluminea density survey in Lake Maraetai, Waikato River, May 2024.
Michele Melchior, NIWA
Research team sorting and collating samples from the May dive survey in Lakes Maraetai and Karaapiro.
In the lab
Brian Smith, ESNZ
Gold clam larvae under the microscope. These juveniles are around 0.2 to 0.3 of a mm making them almost impossible to see with the naked eye. For prospective the average size of a pinhead is 1.5 mm. These are recovered from the passive samplers at Bob’s Landing in March/April 2025.
Research is been undertaken at NIWA’s Ruakura Aquatic Research Facility and by our international collaborator Dr Yu Cao (Wuhan Botanic Gardens) to understand the impact of high clam population densities on aquatic plants.
Dissections help us understand the anatomy and function of this newly-introduced invasive species and how they are adapting to the New Zealand environment.
