Lake users asked to avoid weed infested areas of Lake Wānaka

17 December 2020

Boaties, tourism operators and recreational users on Lake Wānaka are being asked to be extra careful this summer to avoid damaging biodegradable matting installed to control lakeweed.

Land Information New Zealand leads restoration operations on Otago’s lakes. As part of these operations, hessian matting has been laid at a number of sites in Lake Wānaka to supress the spread of the highly invasive waterweed, lagarosiphon. 

Left uncontrolled lagarosiphon takes over lakes, creating dense forests of weed below the water’s surface. It can block boats’ motors, ruin swimming, and smother precious native plants.

LINZ Biosecurity and Biodiversity Group Manager Megan Reid says from mid-late December 15 to 20 marker buoys will be installed at the following locations to clearly mark out areas where matting is laid: 

  • Paddock Bay
  • Glendhu Bluff Bay
  • Parkins Bay

Boat operators need to avoid approaching by boat or fishing across these areas as there’s a risk of prop and fishing lure entanglement which damages the matting and makes it ineffective, she says.  

Check, Clean, Dry – it’s what we do

Ms Reid says as well as avoiding the areas with matting on Lake Wānaka all lake and river users are being asked to help protect and get behind lake restoration efforts.

“The presence of lagarosiphon and the risk of infestation from other water weeds such as hornwort poses a very real and serious threat to the future of Otago’s lakes,” she says.

Ms Reid says checking, cleaning and drying boat props and trailers, jet skis, kayaks and paddleboards, and equipment such as fishing lines before they enter the water limits the spread of weeds. 

“If we want to continue using lakes and rivers as we always have and see native birds, plants and fish return, then we need to check, clean and dry boats and sports equipment between waterways.”

Advice on how to effectively clean equipment to remove weeds is available on the MPI website (see link below) and the Otago Regional Council’s Check, Clean, Dry campaign advocates will be out and about again this summer.

Check, Clean, Dry

Ms Reid say our rivers and lakes are national treasures and culturally important to local iwi;

“There are numerous kāinga mahinga kai (food gathering places) and kāinga nohoanga (settlements) around many of our lakes.

“We use our lakes and rivers to kayak, swim, boat, waterski and take scenic trips. They are vital economic assets, supporting electricity generation and the tourism industry throughout the year and we can’t take them for granted.”

LINZ has significantly increased its investment in biodiversity restoration in Lake Wānaka and other sites as a result of budget increases over the past two years.

More information

To find out more about areas to avoid on Lake Wānaka call 0800 638 943. 

MPI’s Check Clean Dry programme is the national campaign aimed at engaging communities to prevent the spread of lagarosiphon (and other aquatic pests) through checking, cleaning and drying all water sports equipment. Keep an eye out for this year’s Check Clean Dry advocates Mandy, Ben and Sam from the Otago Regional Council.

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