Invasive gold clam in New Zealand waterways

The story so far

Authorities confirmed invasive freshwater gold clams in Taranaki and began increasing detection and prevention efforts in the Whanganui River.^{18 Nov 2025} The species is already established in Waikato and can produce up to 400 juveniles a day under ideal conditions, and the Whanganui River Clam Response Group is working to stop it spreading.^{18 Nov 2025} The clam was found in Lake Rotomanu in New Plymouth on 8 November, the first time it has been found outside the Waikato River.^{10 Dec 2025} In Northland, the deputy chair of the Northland Regional Council called on 3 December for the immediate closure of the Kai Iwi Lakes boat ramp because of the clam threat.^{3 Dec 2025} The Kaipara District Council had previously decided to keep the Lake Taharoa ramp open.^{3 Dec 2025}

Latest

Lake Rotomanu is being drained this week so scientists can assess the clam infestation there.^{10 Dec 2025}

What's next

Lake Rotomanu will be emptied this week to help scientists assess the infestation.^{10 Dec 2025}

Key moments

1. 18 Nov 2025Gold clams confirmed in Taranaki, prompting Whanganui River detection and prevention efforts.
2. 3 Dec 2025Northland council deputy chair calls for immediate closure of Kai Iwi Lakes boat ramp.
3. 10 Dec 2025Clam discovered in Lake Rotomanu on 8 November, first find outside Waikato River.
4. 10 Dec 2025Lake Rotomanu to be drained this week for infestation assessment.

Written from the stories below; each sentence links to its sources.