October 2025
Kia ora koutou,
Welcome to the latest edition of the Check Clean Dry Working Group newsletter, your update on the mahi happening across Aotearoa to protect our precious lakes, rivers and wetlands.
Our network of ambassadors, champions, and partner agencies are gearing up for the summer. From awareness campaigns to boots-on-the-ground initiatives, this edition brings you fresh stories, local highlights, and inspiring examples of how our collective efforts are helping stop the spread of invasive freshwater weeds, pests, and algae.
The Check Clean Dry programme remains a key part of New Zealand’s freshwater biosecurity strategy. empowering water users to take simple steps that make a big difference.
Our Working Group brings together representatives from Bay of Plenty Regional Council, the Department of Conservation (DOC), Environment Canterbury, Fish & Game, Land Information New Zealand (LINZ), Otago Regional Council, Waikato Regional Council and Biosecurity New Zealand.
Together, we’re protecting what we love.
The Check Clean Dry ambassador programme gears up nationwide
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Did you spot us last summer? If you took the Cook Strait ferry, visited a popular lake or river, or attended a water-sport event last summer, chances are the Check Clean Dry campaign popped up on your phone. If you did then you weren’t alone, the ‘Learn More’ button on these advertisements was clicked over 2 million times. Featuring grumpy water-users covered in invasive weeds and pests, the campaign definitely turned heads and is even a finalist in one the NZ Digital Awards categories – watch this space for the outcome. This summer, we're back at it. You might recognise a few familiar faces (and weeds), but we're mixing things up with a fresh look and new messages to keep it interesting and remind everyone that together we can stop the spread of freshwater pests like the freshwater clam. Wherever your adventures take you this season, remember to Check Clean Dry. If you see our campaign, again make sure to give it a click as you never know what, you’ll discover! 
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This summer, you can expect to see Check Clean Dry ambassadors championing the fight against the spread of freshwater weeds and pests, in every region throughout the country. The 2025/26 programme will be bigger than ever, bringing energy and action to our lakes and rivers with one mission: to stop the spread of invasive species through good biosecurity practices. With peak summer recreation season drawing thousands to our waterways, the programme focuses on talking to people at popular lakes, riverside events, and outdoor hotspots. Since launching in the summer of 2018, the ambassador programme has been instrumental in spreading the word on Check Clean Dry. Biosecurity New Zealand will support regional ambassadors through training, providing Check Clean Dry collateral, and ongoing assistance throughout the season to help them engage effectively with kayakers, boaties, anglers, swimmers, and other freshwater users. Their role is to raise awareness of the Check Clean Dry protocol and encourage practical actions that help protect our rivers and lakes. By having informed, respectful conversations, they help people understand how small changes can make a big difference. From working with event organisers and hosting pop-up info stands, to connecting with retailers and water user groups, these local legends are out to make biosecurity second nature for every outdoor enthusiast. Each regional programme is tailored to their region’s needs - whether they are holiday destinations, popular lakes for day-trippers, tramping areas, or places that attract mobile visitors. Ambassadors will also be out maintaining signage, making sure the Check Clean Dry message is seen and heard loud and clear. With every region on board this year, the 2025/26 CCD ambassador programme is set to be a nationwide force for freshwater protection. So, if you're heading to the water, make sure to say kia ora to your local ambassador, and don’t forget to Check Clean Dry when you move between waterways! |
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Lake Karāpiro leads the charge in biosecurity awareness and event excellence
Sir Don Rowlands Centre, Mighty River Domain, Lake Karāpiro. Photo credit: GL Events
Nestled in the heart of the Waikato, Lake Karāpiro is more than just a picturesque setting. It’s a playground for recreational activities such as kayaking, swimming, and powerboating, and is renowned as one of Aotearoa’s premier rowing and waka ama venues, attracting thousands of athletes and spectators each year for major events.
In 2023, Bobs Landing, 1.5km upstream from the Lake, became the first site in New Zealand to detect the invasive freshwater clam. Follow-up testing confirmed its presence from Lake Maraetai Landing to Tuakau.
Minister Hoggard at Bob's Landing with Te Arawa River Iwi Trust, Mercury Energy and Biosecurity New Zealand
The lake remains open for recreational use, but it’s important that all water users do their part by following the Check Clean Dry protocol to prevent the spread of freshwater clams and other pests and weeds, such as hornwort (another challenge for Lake Karāpiro that you’ll read about later in this newsletter) to other waterways.
At the Lake’s centre is the Mighty River Domain, one of New Zealand’s premier event venues. Managed by Liz Stolwyk for over 20 years, this iconic Waipā district location is once again home to the Check Clean Dry ambassador programme, which Liz will lead for the third consecutive summer.
Thanks to the dedication of Liz and her experienced ambassador team, this pathway management approach has become deeply embedded at Karāpiro.
Over the past two years, the Karāpiro ambassadors have raised awareness of freshwater pests at events while working closely with organisers, participants, and spectators. This year they’re helping both new and returning event teams to set up and integrate strong biosecurity measures into their planning and operations.
Backed by Biosecurity New Zealand and Waikato Regional Council, the team’s work now reaches beyond the Lake and includes coordinating event activities across the wider Waikato region in collaboration with Tūwharetoa Māori Business Trust and other regional ambassador teams.
With headline events like the Waka Ama Nationals, Rowing Champs, and Swim Fest set for March 2026, Lake Karāpiro is as busy and iconic as ever and through the leadership of the ambassador team, is proving that hosting world-class events and protecting the environment can go hand in hand.
Waka Ama champions for clean waterways
Photo credit: Waka Ama Aotearoa NZ
Written by Waka Ama Aotearoa NZ
Waka Ama is more than a sport, it's a connection to our waterways, our communities, and our culture. With 102 clubs and 6300+ paddlers, spread from Kaitaia to Invercargill, we have a special relationship with the rivers, lakes, and harbours we train and race in. As kaitiaki (guardians) of our roto (lakes) and awa (rivers), Waka Ama Aotearoa NZ emphasises the importance of following the Check, Clean, Dry steps for our whānau to ensure we do not spread the invasive clam or any other species around the motu.
Every time we move our waka between waterways, we run the risk of spreading freshwater pests like didymo and hornwort. These invasive species can choke our taiao (environment), damage ecosystems, and even make paddling less enjoyable.
By making Check Clean Dry part of our paddling routine when we move between waterways, we protect the places we love and ensure future generations can enjoy clean, safe water for racing, recreation, and wairua (spirit).
LINZ kicks off summer aquatic weed control across Aotearoa
Lagarosiphon at Lake Benore (The Neck). Photo credit: Earth Sciences New Zealand
Written by Toitū Te Whenua Land Information New Zealand
Toitū Te Whenua Land Information New Zealand (LINZ) has kicked off its summer programme to combat two of New Zealand’s most invasive aquatic weeds, hornwort and lagarosiphon, as part of its nationwide biosecurity programme.
At Lake Karāpiro, control work targeting hornwort is about to begin. Using boat and helicopter spraying, LINZ and delivery partner Boffa Miskell Limited will focus on areas near popular boat ramps, ski lanes, and swimming spots.
“Lake Karāpiro is a key recreational and rowing hub,” says LINZ Senior Biosecurity Advisor Shaun Thomason.
“Hornwort forms dense surface reaching mats that smother native aquatic life and choke waterways, so it’s vital we keep it contained.”
In Canterbury, divers have started work in Lake Aviemore, with monitoring and control activities. Once completed, the team will move on to Lake Benmore, with work expected to wrap up there by early November.
Meanwhile, in Otago, divers are working to keep Lake Wakatipu free of invasive weeds by actively monitoring and hand-removing lagarosiphon plants. Additional control efforts are planned for Lake Wānaka, Lake Dunstan, and the Kawarau River over the summer months.
Thomason says keeping lagarosiphon out of Wakatipu is a major priority.
“If it takes hold, it’s incredibly difficult to remove and poses serious environmental and recreational risks.”
LINZ leads this vital biosecurity work in partnership with local councils, community groups, and agencies including Meridian Energy, Environment Canterbury, Contact Energy, Otago Regional Council, Mercury Energy and the Waipā District Council.
To learn more, visit www.linz.govt.nz
The latest on the invasive freshwater clam (Corbicula fluminea)
Photo credit: Earth Science New Zealand
Clams can’t be moved – don’t eat them!
We are often asked if Corbicula, commonly known as the invasive clam, can be harvested and eaten. While they are eaten in some places overseas, the Corbicula clam should not be moved or eaten.
It’s an offence under the Biosecurity Act 1993 to move the clam. They aren’t safe to eat as they are filter-feeding shellfish that eat deposits from the river or lakebed. The clams may also consume harmful algae or other toxins when they feed that may make people sick. See more on the MPI website invasive clam pages
Earth Sciences New Zealand has developed an identification guide for those on the lookout for Corbicula in waterways and lakes. It includes photos showing how to distinguish the clam from the native kākahi and native pea-clam (sphaeriids). Identifying the invasive clam Corbicula
Additional wash stations to support compliance
Planning is underway for additional designated wash stations for boaties using Te Arawa Lakes and Lake Ōkataina in the Bay of Plenty. To enter Te Arawa Lakes or Lake Ōkataina, all boaties must have proof their boats and trailers were cleaned at a designated wash station, if they have been in the Waikato River. The current designated wash station is at 338 Te Ngae Road, Rotorua.
A second wash station is planned for Rotorua and another at Whakatane for this summer, which will save time for those travelling from the Bay of Plenty and north of Lake Ōkataina. The Controlled Area Notices (CANs) will be updated once the new wash stations are in place.
To keep updated see the MPI website: Rules to stop the spread of Corbicula | NZ Government
Surveillance update
Iwi and regional council partners have carried out regular surveillance for the invasive freshwater clam (corbicula) in high-risk water bodies with water sampling and visual surveys and have had no new detections.
Winter and spring surveillance occurred in both the North and South Island and showed no new detections of corbicula outside the current known infested areas. Surveillance includes eDNA and visual inspections in high use waterways.
A surveillance working group including the Department of Conservation, Te Arawa Lakes Trust, Te Uru Kahika and Biosecurity New Zealand is coordinating surveillance efforts. Planning is underway for summer surveillance.
General and special permissions
There are permission requirements in place for specific water users and operators in the Waikato River catchment to help us contain the clam to known areas.
The general permission lists activities allowed for consent holders, commercial users, recreational users, and kai (food) gathering. Kai gathering is permitted in the river for customary harvest of kākahi (freshwater mussels) or tuna (eels). It is an offence to move, gather or harvest the invasive clam because it is an Unwanted Organism under the Biosecurity Act 1993. To find out more click here: General permissions
Special permissions are required for those who need to transfer water or substrates from the controlled area, for example to carry out sampling or research, if activity is not permitted under the General Permissions. To apply for a special permit, email corbiculalongterm@mpi.govt.nz
Ballast tank treatment
Biosecurity New Zealand is working with Earth Sciences New Zealand to test a hot water system designed to safely clean ballasted boats, like wake boats, without spreading freshwater pests such as clams. The system is being trialled on a range of ballast tank types, including hard and soft tanks. Guidelines for the system will be developed to support boat owners and operators to use it. Once the research is complete, we’ll consider how this treatment could be used under the Waikato River Controlled Area Notice.
Reminder: Wake or ballasted boats that have operated within the Waikato River controlled area at any time since 28 November 2023 must stay within the area unless they have an exemption.
Protecting our rivers - protecting whitebaiting
Written by the Department of Conservation.
Every year, New Zealanders fish the rivers of Aotearoa during the whitebait season which runs from 1 September to 30 October. Alongside the enjoyment of this long-standing tradition comes a serious responsibility to protect and support whitebait species and their habitats. Whitebait are the juveniles of six native fish species and four of these are considered threatened, or at risk. At all stages of life, whitebait need clean, unpolluted water to thrive.
The Check, Clean, Dry protocol is a vital piece of New Zealand’s freshwater biosecurity strategy, aiming to curb the spread of invasive pests like gambusia, didymo, hornwort, lindavia, corbicula (freshwater clam), and more. These pests can easily hitchhike on damp fishing gear, clothing, or equipment, and that’s where Check, Clean, Dry comes in for whitebaiters.
Whitebaiting Check Clean Dry sign on the Manawatū river, Foxton Beach Photo credit: DOC
We recommend dedicating your gear to a single river for the season, especially in high-risk areas like Waikato, and following the correct procedures to clean your gear throughout the season and when the season ends.
For whitebaiters, following Check Clean Dry is straightforward. First, carefully Check all nets, waders, buckets, and other gear for plant fragments or debris before leaving a waterway. Clean, all absorbent items by soaking in a 5% bleach solution for one hour, making sure to flush out hollow net frames afterward to avoid spreading bleach in the environment. Dry all gear thoroughly, both inside and out, for at least two days.
Following Check, Clean, Dry helps safeguard whitebait habitats from biosecurity threats, meaning there’ll still be a thriving habitat and tasty whitebait fritters for years to come.
Koi Carp Classic taking on Check Clean Dry
The annual Koi Carp Classic, hosted by the New Zealand Bowhunters Society, returns 1-2 November, and it promises to be bigger and better than ever. Now entering its 35th year, this unique bowhunting competition not only offers thrilling sport enjoyed by all but also plays a vital role in protecting the Waikato River and its catchments from invasive koi carp.
Historically, the record tonnage for koi taken over the weekend stands at 8.6 tonnes. The cumulative total in the history of this event is now past the 100-tonne mark. That’s a lot of invasive koi and their eggs removed from our waterways!
Game Recording Officer Dave Gousmett, who first took aim at koi in 1988, says it’s pretty simple: “Shoot and kill as many koi as possible using a bow and arrow.” Competitors battle it out for top prizes including most carp, heaviest fish, and even the smallest carp, which as you’d imagine requires a serious amount of skill.
A happy hunter Photo credit: NZ Bow Hunters
Beyond the competition, the event supports a broader environmental mission. Koi carp are a serious pest as they degrade water quality, uproot native aquatic plants, and outcompete indigenous species.
Importantly, the organisers are biosecurity-savvy, with clear rules in place to manage the movement of people and gear between waterways during the competition. At the end of the event, all boats and equipment are thoroughly checked and cleaned, and participants are reminded to follow the Check, Clean, Dry protocol, ensuring everything is left to dry for at least two days before entering another waterway.
This is fantastic work by the organisers and participants who are doing their part to stop the spread of aquatic weeds and pests.
To find out more visit: www.nzbowhunters.nz
And that’s a wrap.
As we move further into the summer season, the Check Clean Dry Working Group is focused on building momentum, supporting more coordinated action, deeper partnerships, and stronger community engagement right across the motu. From growing our presence at high-profile events to deepening our mahi with national sporting bodies, we’re continuing to scale up efforts to protect our freshwater taonga.
But success depends on all of us. Please help spread the word, share this newsletter with your networks, colleagues, and communities. The more people we reach, the greater our collective impact.
Whether you’re part of a council, community group, iwi organisation, or simply love getting out on the water—your voice and your actions matter.
Together, let’s keep Check Clean Dry front of mind, every time we move between rivers and lakes.
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