With the whitebait season starting today anglers are being asked to ensure they check, clean and dry their equipment between waterways to avoid spreading fresh water pests.

The Ministry of Primary Industries is asking whitebaiters in the Bay of Plenty to help prevent the spread of didymo and lagarosiphon by following the above steps – check, clean and dry.

National coordination team manager John Sanson says didymo and lagarosiphon pose a serious threat to rivers, streams and lakes.

He says they can clog nets and choke waterways, including whitebait habitats.

'Once in a waterway they can disperse rapidly and destroy the environmental, recreational and aesthetic values of our waterways.

'Restricting your whitebaiting to one catchment only is the best way to stop the spread of unwanted pests. However, if you are going to be moving between waterways we ask you to check, clean, dry any equipment that has come into contact with river or lake water - particularly nets and waders.”

Freshwater pests, such as didymo, are often invisible to the naked eye and can be spread by a single drop of water.

John says people should treat every waterway as though it is infected.

'Even if you can't see the danger you could be spreading it.”

He says before leaving a waterway, people should check items and leave any plant debris they find in their equipment at the waterway.

'All equipment should then be cleaned for at least one minute with a five per cent solution of biodegradable dishwashing solution. That's about one tablespoon of detergent per 250ml.

'Water absorbent materials such as boots and waders require longer soaking times to allow thorough saturation.”

John says 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 to dry for at least another 48 hours before use.

'Following these simple procedures will help slow the spread of freshwater pests throughout New Zealand waterways. It's everyone's responsibility to try to preserve the environmental integrity of our waterways for generations to come.”