Prevention measures introduced for lagarosiphon lakeweed at Frankton Marina

Toitū Te Whenua LINZ and the Lake Whakatipu Aquatic Weed Management Group have introduced prevention measures at Lake Whakatipu to ensure its pristine waters remain weed-free.

Toitū Te Whenua Leader Biosecurity Tracey Burton says isolated lagarosiphon plants found in the Frankton Marina prompted an urgent and proactive approach to prevent it from becoming established in the lake.

“The Frankton Marina is a high-risk site and the Marina owners are now working with the weed management group to reduce the risk of weed fragments dispersing from here to the rest of the lake. This will help ensure Lake Whakatipu avoids an infestation like that seen at Lake Dunstan."

“We kicked off our control works in early October, with a team of divers undertaking surveillance in Lake Whakatipu, including the Frankton Marina which has been added to the control programme,” Ms Burton said.

Lagarosiphon forms thick, dense weed beds that can grow up to five metres tall. They can shade out native aquatic plants, impede water flows, and impact on recreational activities.

Otago Regional Council (ORC) Manager Environmental Implementation Libby Caldwell says monitoring leads to early detection – subsequently reducing the risk of lagarosiphon becoming established. The council supports the national Check, Clean, Dry campaign, with two summer advocates educating water users on how to prevent the spread of freshwater pests.

“Lagarosiphon can spread easily via stem fragments carried by water currents, boats, fishing gear, aquarium and pond escapes. If you are heading out on the water, please check, clean and dry all your gear – especially if you’re moving between waterways,” Mrs Caldwell said.

Queenstown Lakes District Council (QLDC) General Manager Community Services, Kenneth Bailey is encouraged with the progress made to control the weed.

"The environmental health of Lake Whakatipu is of huge importance to all those that live, work and play in the Queenstown Lakes, so successful efforts to proactively reduce, monitor and control this weed in Frankton Arm is a great result."

“QLDC continues to support a robust programme led by Toitū Te Whenua and the weed management group to manage the spread lagarosiphon,” Mr Bailey said. 

In mid-October, ORC council staff attended the World Jet Boat Marathon held in Otago and Canterbury rivers, educating attendees about Check, Clean, Dry and how it protects Otago’s waterways from biosecurity threats including lagarosiphon.

“Water users who check, clean and dry wet equipment between waterbodies play a major role in reducing the spread of lagarosiphon,” Mrs Caldwell said.

The Check, Clean, Dry campaign is led nationally by the Ministry for Primary Industries which partners with local councils. It aims to engage visitors and communities to help prevent the spread of aquatic pest species. 
 
To find out more about Toitū Te Whenua’s biosecurity control work, including current and upcoming lake weed control work, visit the Biosecurity control work section on their website.

https://www.mpi.govt.nz/outdoor-activities/boating-and-watersports-tips-to-prevent-spread-of-pests/check-clean-dry/ 

https://www.linz.govt.nz/our-work/crown-property-management/biosecurity-and-biodiversity/biosecurity-control-work