Hessian matting has been laid at several sites in Lake Wanaka by Land Information New Zealand to suppress 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 said from mid to late December between 15 to 20 marker buoys would be installed at Paddock Bay, Glendhu Bluff Bay and Parkins Bay where the matting had been laid.
Boat operators needed to avoid approaching by boat or fishing across those areas as there was a risk of prop and fishing lure entanglement which damaged the matting and made it ineffective, she said. “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,” Ms Reid said.
Checking, cleaning and drying boat props and trailers, jet skis, kayaks and paddleboards, and equipment such as fishing lines before they entered the water limited 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 was available at Otago Regional Council offices. Check, Clean, Dry campaign advocates would be out and about again this summer, Ms Reid said.
