With the summer holiday season now well underway, Otago Regional Council (ORC) and the Ministry for Primary Industries
are reminding everyone in Otago of the importance of cleaning their equipment between waterways to avoid the spread of
unwanted freshwater pests including the invasive alga didymo.
“Unwanted freshwater pests such as didymo, lake snow, and hornwort pose a serious threat to our rivers, streams and
lakes. Once in a waterway they can disperse rapidly and destroy the environmental, recreational and aesthetic values of
our waterways,” says Richard Lord Team Leader Biosecurity.
“We are asking people moving between waterways to Check, Clean, Dry any equipment that has come into contact with river
or lake water. Some freshwater pests, like didymo, are microscopic and can be spread by a single drop of water. Even if
you can’t see the danger you could be spreading it.”
Mr Lord says before leaving a waterway, people should check items and leave any weed or debris they find at the
waterway.
“All items should then be cleaned for at least one minute with a five percent solution of biodegradable dishwashing
solution. That’s about one tablespoon of detergent per 250ml.”
“Water absorbent materials such as lifejackets, wetsuits and boots require longer soaking times to allow thorough
saturation.
“Drying will kill didymo, but even slightly moist items can harbour didymo and other microscopic pests for months. To
ensure didymo cells are dead by drying, the item must be completely dry to the touch, inside and out, then left dry for
at least another 48 hours before use,” says Mr Lord.
“Following these simple procedures will help slow freshwater pests like didymo from spreading throughout New Zealand
waterways. It’s everyone’s responsibility to try to preserve the environmental integrity of our waterways for future
generations.
“Just remember to Check Clean Dry when moving from one waterway to another, anywhere in New Zealand.”
For more information about didymo and freshwater pests go to: www.mpi.govt.nz/check-clean-dry.