Freshwater gold clams, which represent an enormous threat to New Zealand freshwater. Photo: Earth Sciences New ZealandThe gold clam, a southeast Asian freshwater mollusc bivalve shell, has been found in the Waikato River and elsewhere nearby. The gold clam, Corbicula fluminea, is a hermaphrodite and can self-fertilise, helping it to multiply extraordinarily rapidly. Gold clams could be imported in small boats. Gold clams were recently found in Lake Rotomanu, New Plymouth, forcing authorities to drain the entire lake out to sea.

Source: Otago Daily Times January 20, 2026 16:19 UTC