Updated management plans have been released for Lake Dunstan, Lake Wakatipu, and Lake Wānaka as part of long-term efforts to protect them from the aquatic weed lagarosiphon.  

The 10-year-plans were developed for Toitū Te Whenua Land Information New Zealand (LINZ) by Earth Sciences New Zealand (formally NIWA), in collaboration with local lakeweed management committees.  

LINZ biosecurity manager Tracey Burton said the plans focus on controlling and preventing the spread of lagarosiphon, one of New Zealand’s worst aquatic weeds.  

“If left unchecked, lagarosiphon can form dense weed beds that smother native aquatic plants and restrict recreational access,” she said. 

“With lagarosiphon currently confined to only a few lakes in the South Island, our updated management plans will help us stay ahead of the spread and ensure these iconic lakes remain healthy for people and nature, now and into the future.” 

Tracey said the plans are tailored to reflect the unique conditions of each lake and the extent of lagarosiphon infestation, and the goal for Lake Dunstan is “to minimise the impact the weed is having”. 

The plans incorporate the latest research and best practices for controlling lakeweed, including hessian mats, divers hand-cutting weeds in high-use areas, aquatic herbicide, ongoing monitoring and surveillance, and public awareness initiatives to encourage lake users to check, clean, and dry their gear.  

The plans were developed in collaboration with stakeholders including local community groups, regional councils and other organisations to take a coordinated approach to controlling lagarosiphon. 

“These plans are a great example of collaborative biosecurity in action. Everyone has a role to play in protecting our lakes, from government agencies to lake users,” Tracey said. 

The new management plans are part of the LINZ wider biosecurity and biodiversity programme. 

LINZ aquatic weed control programme in the Otago region, delivered by its biosecurity partner Boffa Miskell Limited, is scheduled to begin in October. 

View the management plans here.

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