Duckshooters asked to avoid spreading water pests

This piece of live hornwort - a nuisance weed - was found on a boat trailer moving from Lake Taupō to Lake Otamangakau, where there is no known hornwort. Photo / supplied

Duck shooting is startng this weekend and shooters are reminded to clean their equipment between waterways - to avoid spreading fresh water pests.

Horizons Regional Council and the Ministry for Primary Industries are hoping shooters will check, clean and dry between waterways to avoid spreading nuisance organisms - including the invasive algae didymo.

Horizons biosecurity programme coordinator for plants Craig Davey says unwanted freshwater pests such as hornwort pose a serious threat to our duck shooting waterways.

"Once in a waterway aquatic plant fragments can disperse and grow rapidly, destroying the environmental, recreational and aesthetic values of our waterways. We are asking hunters moving between waterways to check, clean, dry any equipment that has come into contact with river or lake water – particularly decoys and boots.

"Some freshwater pests, like didymo and lake snow, are microscopic and can be spread by a single drop of water. It is very easy to spread pests without knowing you are," Davey explained.

Before leaving a waterway, people should check items and leave any weed or debris they find behind.

All items should then be cleaned for at least one minute with a five percent solution of biodegradable dishwashing solution. This is approximately one tablespoon of detergent per 250ml.

Water absorbent materials such as 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," Davey said.

"Following these simple procedures will help slow freshwater pests like didymo from spreading throughout our waterways. It's everyone's responsibility to try preserve the environmental integrity of our waterways for future generations."

For more information about freshwater pests visit www.mpi.govt.nz/check-clean-dry.