INVASIVE GOLD CLAM: WHAT YOU NEED TO KNOW TO HELP STOP THE SPREAD

The invasion of the gold clam in New Zealand fresh waterways is an ongoing concern and paddlers must do their part to prevent the spread of the pest species.

The freshwater gold clam was discovered in the Waikato River in May 2023, and has since been officially classified as an “unwanted organism”. This means under the Biosecurity Act, it it is now illegal to “knowingly move or spread the freshwater gold clam or water that may contain it”.

If you are paddling in various locations within the Auckland, Waikato and Bay of Plenty areas, it is important you stay informed, take preventative measures, and support conservation efforts over the course of the coming summer.

Prevent the Spread- Check, Clean, Dry

It is incredibly easy for this pest to hitch a ride and take up residence in another location. New guidelines have been released on how to Check, Clean and Dry your boat and gear so you do not spread this or any other invasive species around when you train or compete:

If you are only using your boat and gear at ONE location:
Ensure you check and flick off any visible matter like weed, mud or adult clams, and then you are good to go.

If you are paddling at various locations, please undertake the Check, Clean and Dry method outlined below before paddling in a new water way:

CHECK for what is visible:

Flick off any visible matter like weed, mud or adult clams at the lake or river. Drain river or lake water, including removing bungs or opening hatch covers in case there is water in enclosed areas and leave to dry.

CLEAN for what is invisible:

Blast your boat inside and out with a hose, using tap-water and onto grass, beside the waterway, at the club or at home (not into a stormwater drain). Blast the paddle as well, especially if it has a split shaft.
For absorbent materials, use one of these treatments and
refer to the manufacturer’s instructions if needed:

• Soak
  in hot tap water (50°C to 55°C) for at least 5 minutes, or
• Soak
  in 5% bleach solution (5-litre mix = 250ml bleach in 4.75 litres water)
  for an hour, or
• Freeze
  till solid (overnight), or
• Soak
  in salt solution at 100ppt (parts per thousand) (5-litre mix = 500g salt
  in 5 litres warm water) for 4 hours.

DRY to be sure:

• Gear: allow gear to dry to touch, inside and out, then leave it to dry for at least 48 hours (2 days) before using again.
• Watercraft: 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 48 hours (2 days). The hull of a watercraft will dry when towed.

See full updated guidelines specific for paddlers- Waikato update for kayakers and canoeists (mpi.govt.nz) 

Why is the Gold Clam an issue?

These clams reproduce rapidly and form large populations that can clog water-based infrastructure such as electricity generation plants, irrigation systems, and water treatment plants. They are filter feeders that can potentially compete with native species for food.

Overseas, the clam has proven damaging and difficult to control. Freshwater gold clams are able to produce up to 70,000 juveniles a year, and able to survive a wide range of temperatures and salinities.

Preventing the spread to further waterways is the course of action at this stage.

Remember that awareness is the first step in reducing the impact of the golden clam invasion. We encourage you to stay informed about areas where golden clams have been identified, and any local regulations that may be in place.  Canoe Racing NZ will be keeping our community updated and informed.

For further information, including reporting procedures of suspected sightings, please visit: https://www.mpi.govt.nz/biosecurity/exotic-pests-and-diseases-in-new-zealand/pests-and-diseases-under-response/freshwater-gold-clam/