Response to freshwater gold clam discovery in Waikato River

Friday 26 May 2023, 5:53AM

By Waikato Regional Council



Waikato Regional Council has responded to news today that a highly invasive freshwater gold clam has been discovered across a 45km stretch of the Waikato River.

The announcement was made by Biosecurity New Zealand, which is leading the national response in partnership with mana whenua, after the discovery of the new-to-New Zealand clam species near Lake Karāpiro.

Initial checks have found the freshwater gold clam present from 1.5km upstream of Bob’s Landing and downriver to Wellington Street Beach in Hamilton.  

Waikato Regional Council Chief Executive Chris McLay said: “It is hugely disappointing that this invasive species has been discovered in the river, which is a vital source of life for such a large part of our rohe.

“It’s been found over an especially popular stretch of the river. Lake Karāpiro alone has 50 days of events every year that attract thousands of competitors, and through summer our maritime officers can find hundreds of boats, jet skis and kayaks using the lake on any given day. Even in winter it continues to be heavily used.

“It’s possibly one of the most busy and congested stretches of inland water in New Zealand.

“To protect our precious waterways – not just here in the Waikato region, but right around New Zealand – we strongly urge water users to make sure they’re following the Check Clean Dry approach. It will be vital to stopping the spread of this species elsewhere,” Mr McLay said.

Waikato Regional Council is taking guidance from Biosecurity New Zealand and supporting the national response that’s now underway under their leadership.

To help identify the species, there is full information, including clear images of the clam, on the Biosecurity New Zealand website at:

Suspected sightings can be reported to Biosecurity New Zealand on 0800 80 99 66 or by completing the online reporting form at It is helpful to note the precise location and provide a close-up photo of the clam as well as one that shows the surroundings. Please do not disturb the organism. 


Remove any visible matter, including any clams you can see, along with plant material or mud. Drain all river water.


Do a washdown of your gear and watercraft with tap-water onto grass, beside the waterway or at home and not into a stormwater drain system. This will flush off clam larvae, which can be too small to be seen.

For gear made of absorbent materials, which will stay wet longer, apply a cleaning treatment.


Allow gear to dry to touch, inside and out, then leave it to dry for at least 5 days.

Dry areas inside the watercraft where water has pooled, for example with an old towel, and then leave the craft to dry for at least five days. The hull of a watercraft will dry when towed.