Mō ngā awa te aroha, he waiaroha — For the love of rivers
Freshwater pests like didymo and the invasive gold clam damage river ecosystems and the native life they support. Paddle craft and gear are a high risk for carrying pests between waterways. River conservation is an important aspect of WWNZ, which is why we want all river users to Check, Clean, Dry every time we move between rivers.
The invasive gold clam (Corbicula) was found in the Waikato River in 2023 and has since spread along it from Lake Maraetai to Port Waikato. In late 2025 it was confirmed in Lake Rotomanu in New Plymouth, with warnings issued for the Whanganui River.
Gold clam is an Unwanted Organism under the Biosecurity Act. You must not knowingly move the clams, or water that may contain them, and they are not safe to eat. A Controlled Area covers the Waikato River from the Whakamaru Dam to Port Waikato. If your gear or craft has been in that water, you must follow the Check Clean Dry steps before moving it elsewhere.
There is a specific, updated Check Clean Dry method for the North Island. Because the situation keeps changing, always follow the current official advice.
Watch the video for advice on cleaning your kayak. Other paddle craft follow the same steps.
For the current, official method, see the Check Clean Dry advice here.
If you think you have seen gold clam, note the location, take a photo, do not handle it, and report it to Biosecurity New Zealand on 0800 80 99 66.
