Are you using the Waikato River and its lakes?
There are new specific 'Check, Clean, Dry' requirements for that area to prevent the spread of the freshwater gold clam.
Get the 'Check, Clean, Dry' requirements for freshwater gold clam (Corbicula fluminea)
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On this page:
- Clean all gear when moving between waterways
- Legal requirement to clean gear
- The 'Check, Clean, Dry' method
- Treatment by drying
- Cleaning specific items
Clean all gear when moving between waterways
Invasive freshwater pests, including didymo, could squeeze the life out of our country's most precious rivers and lakes. They can be spread by a single drop of water or plant fragment or single fish egg. You can help to protect your favourite waterways if you always check, clean, then dry any equipment that comes into contact with the water, between every waterway, every time.
Video: Why you need to 'Check Clean Dry' when you move (3:16)
Transcript – show/hide
[ Footage of people enjoying water activities: A boat on the lake, people kayaking on a river, people fishing in a lake, people rafting in a river, kids swimming in a lake, a woman paddling on a lake.]
[Dr Tracey Burton, Manager Biosecurity and Biodiversity, Toitu Te Whenua – Land Information New Zealand, is sitting near a lake and talks to the camera.]
Dr Tracey Burton: Like many New Zealanders, I enjoy spending time around our lakes and rivers and feel a real connection to them.
[2 divers are in a lake with a notepad doing dive surveys.]
Dr Tracey Burton: For 20 years I was a freshwater ecologist carrying out dive surveys looking below the surface of the water.
[Footage of underwater meadows, kākahi and koura.]
Dr Tracey Burton: And in many of our New Zealand lakes, we have these beautiful underwater gardens, diverse communities of plants that grow right across the lake bottom and support a diverse range of other species. And this includes our taonga species such as our freshwater mussel, the kākahi, and the freshwater crayfish, the koura.
[Underwater footage of dirty water full of pest weeds.]
Dr Tracey Burton: But many of our rivers and lakes are now under attack from invasive weeds and pest species.
These species are destroying underwater ecosystems and threatening the mauri, the life force, and health of these rivers and lakes.
[Dr Tracey Burton is talking to camera.]
Dr Tracey Burton: By healthy, we mean a water body that's unimpacted by weeds and pests and supports a diverse range of life. A system that has good water quality and can support a healthy food web for the other species that live in these systems.
[Footage of an aerial view of a lake, then of a bird looking for food in a lake and of kōkopu. Diverse videos of people enjoying water activities like biscuiting, boating and fishing, then irrigation in a field and a hydro-power plant.]
Dr Tracey Burton: New Zealand has a diverse range of native plants, fish and invertebrates and birds that depend on these freshwater environments. And many of these species are endemic, found nowhere else in the world like the giant kōkopu. We also enjoy healthy water for swimming, for boating, for fishing and for the scenery. And water is also used for drinking and irrigation and power generation.
[Dr Tracey Burton is talking to camera. The 'Check, Clean, Dry' logo appears.]
Dr Tracey Burton: Understanding the threat of these invasive species helps us to see why it's so important to check, clean and dry our gear before we move between waterways.
[Underwater footage of each pest is shown as Dr Tracey Burton describes it.]
Dr Tracey Burton: Hornwort is New Zealand's worst submerged weed species. So, it can grow up to 8 metres tall. That's taller than a house and can form these large, dense floating nets on the surface of lakes. In river systems, these can roll down the system, causing real havoc to recreational activities.
Fortunately, this weed is only known to be in the North Island. Other weed species, including egeria and lagarosiphon, this is the one with the curly leaves, that are also having a big impact. These weed species have come into New Zealand with no competition. They grow faster and taller than any of our native species. And they are known as space invaders. When they come into a lake system, they simply take it over. They smother out the native plants and destroy habitats. You've probably heard of the alga didymo, or rock snot that forms these brown, slimy masses on rocks and plants in southern rivers and lakes. More recently, we've been seeing the spread of another algae called lindavia, which produces a mass of sticky mucus strands in our lakes. Invasive pest fish are also causing havoc, like the catfish and the koi carp that feed by hoovering off the bottom, creating a real mess, stirring up the sediments and creating really bad water quality.
[Dr Tracey Burton is talking to camera.]
Dr Tracey Burton: Once established, invasive species are difficult, if not impossible, to remove and can change our lake and river systems forever.
Prevention remains our best line of defence. And the common factor for the spread of these invasive species is people. It's us moving these species around.
[Message on the screen: Helps protect your lakes and rivers]
[The 'Check, Clean, Dry' logo appears, and an acknowledgement to Dr Tracey Burton and NIWA. The logos for Biosecurity New Zealand and Ko Tātou/This Is Us appear at the bottom of the screen.]
[End of transcript]
Video – How to 'Check Clean Dry' your boat and gear (2:26)
Transcript – show/hide
[The 'Check, Clean, Dry' logo is seen with a spray bottle]
[Ashton Reiser, New Zealand elite sprint kayaker is at a lake and talking to the camera.]
Ashton: Kia ora. Like a lot of New Zealanders, I really enjoy being active in our rivers and lakes.
[Video of Ashton kayaking on the lake. There is hornwort on his paddle.]
Ashton: But we all need to be careful not to take nasty hitchhikers with us if we move to another lake or river. Because invasive weeds and pests like didymo and hornwort can choke our fresh waters.
[Ashton walks around a boat, talking to the camera and showing pieces of weed on the anchor, boat and trailer.]
Ashton: And that's why we need to check, clean, dry. There are a few things to know. Firstly, if you move between waterways, there's a risk of spread. Secondly, some parts of your gear are more risky than others. Like places on your trailer where weed can snag.
And remember to check your anchor and any places where water can pool and keep unwanted organisms alive.
Let's go through the 3 steps of check, clean, dry.
[The 'Check, Clean, Dry' logo appears with a spray bottle. The word "Check" is highlighted.]
[Ashton is seen looking over the boat and all its gear, including the anchor and chain, propeller, and tow hook-up, and picking any plant material he finds. He leaves them on the bank and puts some in a rubbish bin.]
Ashton: Check your gear and take off any bits of weed you can see.
Leave it on the bank or put it in a rubbish bin. Never wash weeds down the drain.
[The 'Check, Clean, Dry' logo appears with a spray bottle. The word "Clean" is highlighted.]
[Ashton is sitting on the grass with a plastic bin of water and a bottle of dish detergent. He is using a measuring cup to put detergent into the water.]
[Message on the screen: For things you can’t see, use 10% dishwashing liquid with water.]
Ashton: Clean any gear that's been in contact with lake or river water using a cleaning mix. That will kill algae like didymo or lake snow. Most people use a mix of 10% dishwashing liquid with water. But you could use 2% bleach or hot water.
[A lifejacket is shown being submerged in the bucket of sudsy water. Then a hand switches on a water tap.]
Ashton: Using water alone doesn't kill these weeds and pests. In fact, it keeps them alive longer. Leave for 10 minutes before rinsing with tap water.
[Ashton sprays cleaning mix all around the boat, like the engine turbine, anchor rope and carpet areas.]
Ashton: Be strategic. Spray the areas that could remain damp or wet.
Include gear that's made of absorbent materials like the anchor rope or carpeted areas.
When you tow your boat, the outside of the house should dry. So you don't need to clean that.
[The 'Check, Clean, Dry' logo appears with a spray bottle. The word "Dry" is highlighted.]
[Ashton walks around the boat. On screen is an image of didymo on a fishing rod. Different parts of the boat are shown dry]
Ashton: It's best if your boat and gear are completely dry before you go into another river or lake. Didymo for example, can survive for a month on damp gear. Drying completely is an acceptable alternative to cleaning with detergent.
That's it for powerboats. And these principles apply to all water activities. This is how we protect our rivers and lakes from freshwater invaders for generations to come. So, are you in?
[The truck drives aways towing the boat.]
[Message on the screen: Helps protect your lakes and rivers]
[The Check, Clean, Dry logo appears, and an acknowledgement to Ashton Reiser and NIWA. The logos for Biosecurity New Zealand and Ko Tātou/This Is Us appear at the bottom of the screen.]
[End of transcript]
Legal requirement to clean gear
The South Island is a Controlled Area for the invasive freshwater algae didymo (also known as rock snot), which was first detected there in 2004. This makes it a legal requirement to clean all gear used in the water before going from one South Island waterway to another waterway. So far, no didymo has been found in the North Island.
Under the Biosecurity Act (1993) there is a requirement not to spread invasive freshwater weeds and pests anywhere in New Zealand.
The 'Check, Clean, Dry' method
To prevent the spread of invasive freshwater pests (like didymo), whenever you move between waterways you must check, clean, and dry all your gear that comes into contact with water. If you don't want to treat your gear, make sure you only use it in one waterway.
Check
Remove any plant matter from your gear and leave it at the site (the river or lake bank), or put it in the rubbish. Don't wash plant material down any drain.
Clean
Use 10% dishwashing detergent mixed with water and leave the item wet for 10 minutes.
The rule of thumb for 10% detergent mix is:
- for a 250ml (small) spray bottle, put in 1 and half tablespoons
- for a 500ml (large) spray bottle, put in 3 tablespoons
- for a 10-litre bucket, put in 1 litre of detergent.
Cleaning options
| Option | Amount | Treatment time2 |
|---|---|---|
| Dishwashing detergent or nappy cleaner | 10% mix | Soak or spray all surfaces and leave wet for at least 10 minutes |
| Bleach | 2% mix (200mls diluted to 10 litres in water) |
Soak or spray all surfaces for at least 1 minute |
| Hot water1 |
Above 60°C Above 45°C |
Soak for at least 1 minute Soak for at least 20 minutes |
| Freezing | Until solid | |
|
1 60°C – hotter than most tap water; 45°C – uncomfortable to touch 2 Allow longer times for absorbent items. |
||
Cleaning large volumes of gear
If you have large amounts of gear (for example if you have a fishing or diving business), you can find other suitable options in Appendix 3 of Check, Clean, Dry: Information for sporting event organisers.
'Check, Clean, Dry' for sporting event organisers [PDF, 2.6 MB]
Make sure you:
- follow the manufacturer's safety instructions for any cleaning products
- choose a method that won't damage your gear
- check the cleaning mix has penetrated right through the item before you soak it for the recommended time
- check our cleaning instructions for specific items – some have different cleaning requirements.
Dry
Ensure your gear is completely dry to touch, inside and out, then leave dry for at least another 48 hours before you use it (didymo can survive for months on moist gear).
Treatment by drying
Drying can be used as stand-alone treatment for non-absorbent items if you take great care to:
- make sure gear is completely dry to touch, inside and out
- leave dry for at least another 48 hours (after drying), before entering a different waterway.
Cleaning specific items
Most items can be cleaned using the standard 'Check, Clean, Dry' method, but some have additional requirements.
