Freshwater gold clam

General description

There are no other New Zealand freshwater shellfish that look anything like the gold clam.

The adult clams are 2-3cm in length and are typically dirty white, yellow or tan in colour.

They have an obvious ribbed texture on the shell.

They are found in freshwater or brackish water, sitting on top of sandy or muddy substrates or buried shallowly within them.

It was first found in the Waikato River in May 2023. Gold clam has not yet been found in the Auckland Region.

What you need to know

To help protect our environment:

• You must not distribute or release any freshwater gold clam within the Auckland region.

If you swim, boat or row in the Waikato River, follow the Check Clean Dry guidelines to help stop the spread of this clam to other rivers and lakes.

Habitats

Lakes, rivers, estuaries.

Impact on environment

This shellfish is native to eastern Asia but has become widespread in North and South America and Europe where it has become a pest.

Freshwater gold clams are prolific breeders, able to produce large populations groups that can clog electric generation plants, irrigation systems and water treatment plants.

Their shells will wash up and smother sandy lakeside beaches.

They can potentially compete with native species for food.  However, we do not yet know how this species will respond in New Zealand conditions.

Control

Check equipment and vessels for freshwater pests, clean everything that has been in contact with the water and dry everything thoroughly.

For more information about the freshwater gold clam or to report a sighting contact Biosecurity New Zealand 0800 80 99 66.