Keeping Gisborne didymo free

An awareness campaign to combat the threat of didymo or ‘rock snot’ in Gisborne waterways is underway over summer.

Didymo awareness advocate Toni Stirton will be visiting local freshwater spots. She will be talking to people about the importance of checking equipment, cleaning it and drying it properly before leaving the water. ‘This is the best way to prevent didymo and other freshwater pests from spreading into our clean waterways,” says Ms Stirton.

Didymo is a microscopic algae that can be spread through a single drop of water. It can survive a long time in moist conditions out of waterways.

“Even if you cannot see it you could be spreading it that is why it is so important to ‘Check Clean Dry’ every time.”

‘Check Clean Dry’ is a habit all New Zealanders and visitors need to adopt when doing freshwater activities. The didymo algae have already spread throughout some rivers, streams and lakes in the South Island, and there has been a major effort to stop it getting into North Island waters.

Didymo is nicknamed ‘rock snot’ as it forms a thick slime on the rocks and base of a river. It harms native fish, trout, plants and insects. Rivers, streams and lakes become really unpleasant to go swimming, boating or fishing in. It is invisible in water until it gathers to form a smelly, slimy mat. It sticks to river beds by stalks and can form flowing ‘rats tails’ that turn white at the ends and look similar to tissue paper.
Preventative measures for all freshwater pests include checking and removing all obvious debris, cleaning and soaking all gear and equipment in a five percent detergent and water solution for five minutes, drying all gear completely then leaving it to dry for a further 48 hours.

Trevor Freeman, environmental services manager with Gisborne District Council is grateful for the Biosecurity NZ funding that has enabled Toni to spread the message in this district and down to as far as Wairoa. "Aquatic pests are very difficult to eradicate, if not impossible. Every freshwater user needs to take responsibility for keeping them out".

The Gisborne District Council and the Department of Conservation have collaborated to reinforce the ‘Check Clean Dry’ message. Any suspected sightings of the algae in the Gisborne region should be reported to MAF Biosecurity New Zealand on 0800 80 99 66.