Invasive freshwater clams can survive in a wide range of environments
Two species of invasive freshwater clams are present in the North Island.
- Corbicula fluminea (commonly known as 'gold clams') is native to eastern Asia and is widely established in North and South America, and Europe.
- Corbicula australis is native to Australia, where it is common and widely distributed.
They are fast breeders and can clog facilities like water treatment plants
Corbicula are prolific breeders, able to produce 400 juveniles a day and up to 70,000 juveniles a year, allowing them to reach extremely high densities in optimal conditions.
Top: Corbicula australis clam shells (A to E). The picture on the right (A, B, C) shows various sizes of the clam shells to scale. A 5 mm line is shown bottom right for reference.
Bottom: Corbicula fluminea clam shells (F to J). The picture on the right (D and E) shows 2 sizes of the clam shells to scale. A 5 mm line is shown bottom right for reference.
Photo credits: Jean-Claude Stahl and Kerry Walton, Te Papa.
Where the clams have been found in New Zealand
Corbicula fluminea: It was found at Bob’s Landing in the Waikato River near Lake Karāpiro in May 2023, and later in the Waikato River from Lake Maraetai Landing to Tuakau. It was found in Lake Rotomanu, a small man-made lake in Taranaki, in November 2025.
Corbicula australis: It was found in March 2024 in a small man-made lagoon at the Lake Taupō Aqua Park, where it is being eradicated.
