Check, Clean, Dry: preventing didymo and other pests

[ 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]

[Footage of champion rower Mahé Drysdale, spraying a boat with water from a hose next to a lake.]

[Mahé talks to the camera, and we see images of his past success and video of his family paddling.]

"Kia ora. Like many New Zealanders, as a family, we really enjoy being active in our lakes and rivers."

[A car is seen towing a boat up the slipway, followed by footage of a boat on a river or lake.]

"But we all need to be careful not to take a nasty hitchhiker with us if we move to another lake or river.

"Because weeds and pests like didymo, hornwort, and the invasive clam can choke our fresh waters.

[Images of didymo, hornwort, and freshwater clams are shown.]

[Mahé is seen standing by a boat.]

"The rules have changed, so let's make sure you're up-to-date. Here are the three steps of Check, Clean, Dry."

[Mahé is shown, checking under and around a boat.]

"Check, for what's visible."

[Mahé removes weed from the boat.]

"Check your boat and gear and take off any weed or other matter that you may see."

[Mahé throws weed on the bank and puts weed into a bin.]

"Leave it on the bank or put it in the rubbish bin. Never wash it down a drain."

[Footage of a life jacket with weed on it, footage of an anchor with weed.]

"Remember to check your life jackets, your anchor, and any rope that's been in the water."

[Mahé checks under the bow of the boat and on the trailer]

"Get down and look under your boat and trailer too."

[Mahé drains water from the boat and pulls out a bung on the boat]

"Drain all water and remember to pull out all bungs from around your craft.

[Mahé faces the camera and then walks beside the boat and faces the camera again]

"Clean, for what's not visible. This is for all the things that are too small to see. Like fish eggs, tiny clams, or algae. Just because you can't see them doesn't mean they're not there.

[Footage of Mahé spraying the side of a boat with a hose.]

"How to clean. First, give all your craft and gear a good blast. Use tap water and don't let it run into a stormwater drain. Wash out places where things can get stuck."

[Footage of Mahé soaking a life jacket.]

"Next, use a treatment to clean gear made of absorbent materials like life jackets. You have three main treatment options."

[Details of the hot water treatment are visible on the left of the screen.]

"The most effective is very hot water."

[Detail of the bleach treatment are shown on the left of the screen]

"Or you could soak it in water with household bleach."

[Details of the freeze option are shown on the left of the screen]

"Or the third option is to freeze the item until solid, which is usually overnight."

[Picture of a boat and the word "Dry" is shown on the right of the screen.]

"Dry, to be sure."

[Footage of Mahé leaning on a boat at a river or lake.]

"And finally, any moisture helps these weeds and pests survive. So it's important you let everything dry."

[The camera zooms in to show different parts of a boat.]

"Firstly, make sure your craft and gear is completely dry to touch, inside and out. If you tow your boat for 20 kilometres on a hot day, the hull will dry."

[Footage of Mahé walking towards a boat.]

"But you may need to dry out pooled areas inside the craft with an old towel."

[Footage of a hand using a towel to dry the inside of a boat.]

"And then, leave everything to dry for at least another two full days before you use it again."

[Footage of Mahé walking towards and around a boat.]

"So those are the basics for boats. And the principle is the same for any craft or gear that you may use. That's how we protect our lakes and rivers from these freshwater invaders for generations to come.

[Mahé looks at the camera.]

"So, are you in?"

[Footage of a boat pulling up the slip way and hill with a 'Check Clean Dry' propeller protector.]

[The words 'Check Clean Dry' are shown on screen.]

[End of transcript]

[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]