DOC call to prevent spread of invasive algae
Nelson Lakes National Park visitors are being asked to use new cleaning stations to prevent invasive algae spreading to the park’s pristine alpine lakes and rivers.
The microscopic algae lindavia and didymo, which can produce snot-like blooms, are in the national park’s lakes Rotoiti and Rotoroa, and in Lake Tennyson on the park’s eastern edge. The algae are also in some Marlborough rivers.
Lindavia arrived accidentally and was identified in the Buller River in 2019 and then in Lakes Rotoiti and Rotoroa. It’s also in Lake Tennyson in Molesworth Recreation Reserve and Nelson’s Maitai reservoir.
The Department of Conservation (DOC) asks people to clean gear that is wet or damp from any river or lake water at cleaning stations near the main access points at Coldwater, Lakehead and Sabine huts.
“Gear needs to be soaked for just 10 minutes in the 10% detergent solution at the cleaning stations to kill the microscopic algae,” says Melissa Griffin, DOC Nelson Lakes Senior Biodiversity Ranger.
“If gear has been dry for at least 48 hours and is bone dry, it’s safe to use. But, if people have swum in Lakes Rotoiti or Rotoroa one day and they plan to swim elsewhere the next day, their togs should be treated with the detergent solution even if dry.”
Lindavia can cause a sticky mucus-like substance known as ‘lake snow’ that hangs below the water surface. Didymo, also known as ‘rock snot’, can form large, unsightly mats on the bottom of lakes, rivers, and streams.
For the third summer, there will be hut wardens at Blue Lake Hut to speak with trampers about preventing the spread of the algae and other aquatic pests in Nelson Lakes.
The hut wardens will also talk about respecting the sacredness of Rotomairewhenua/Blue Lake, and Rotopōhueroa/Lake Constance which are tapu/sacred to mana whenua iwi, particularly to Ngāti Apa ki te Rā Tō. People are asked not to touch the water in these lakes or to swim in them to uphold their mauri/life force and purity.