Don’t let clams hitch a ride

How you can help stop the spread of invasive clams  

The invasive freshwater clam can be as small as a grain of sand. They can attach to surfaces like boats, wetsuits, and other gear. Because they can be invisible to the naked eye, they can be moved between waterways undetected.

If you’ve been in a lake, river, stream, or wetland and plan to visit another waterway, 'Check Clean Dry' your boat and gear before you move. 

North Island

How to Check Clean Dry in the North Island

South Island

How to Check Clean Dry in the South Island

Using the Waikato River 

The invasive freshwater clam is known to be present from Lake Maraetai Landing to Tuakau. There is a Controlled Area Notice in place that must be followed for all water users on this section of the Waikato River.

Waikato River Controlled Area Notice

Other lakes and rivers 

Bay of Plenty’s Te Arawa lakes also have a Controlled Area Notice in place. And there are extra protections for Lake Ōkataina.  

Te Arawa Lakes Controlled Area Notice

In Taranaki, the invasive clam was found at Lake Rotomanu on 8 November 2025. Check the Taranaki Regional Council's website to keep up to date with developments.

Council news – Taranaki Regional Council

Not for eating or gathering

During feeding, invasive clams soak up harmful toxins that can make people sick. For this reason, they are not safe to eat.

It is also illegal (under the Biosecurity Act 1996) to knowingly move the clams or water that may contain them.