GUEST
Visitors to Nelson Lakes National Park are being asked to help to protect its pristine alpine lakes from an alga that causes mucus-like ‘lake snow’.
The microscopic alga Lindavia that causes the sticky mucus-like substance known as ‘lake snow’ `is in the park’s Lake Rotoiti and Lake Rotoroa.
Department of Conservation wants to prevent it being spread to other lakes in the park; Rotomairewhenua/Blue Lake, Rotomaninitua/Lake Angelus and Rotopōhueroa /Lake Constance and to alpine tarns.
To help safeguard Blue Lake, which is thought to have the clearest freshwater in the world, and other lakes, hut wardens are at the busy Blue Lake Hut over the summer peak visitor season to speak to trampers about preventing the spread of Lindavia and other aquatic pests.
Blue Lake Hut Warden Shep Joice, who grew up in Saint Arnaud, has been posted to the hut since December and will be joined by rostered volunteer wardens until Easter.
Both Blue Lake and Lake Constance are tapu (sacred) to Ngāti Apa ki te Rā Tō iwi, and people are asked not to touch the water in these lakes to uphold their mauri (life force) and pureness.
“The Blue Lake hut wardens are talking with visitors about respecting the sacredness of Rotomairewhenua and Rotopōhueroa lakes by not touching the water or swimming in these lakes,” DOC community ranger Sandra Wotherspoon says.
“People shouldn’t wash or put anything in the lakes, including not filling drink bottles.
She says this will also help protect Blue Lake’s outstanding water clarity from being ruined by lake snow.
“Already this summer, there have been up to 50 people staying at the hut and campsite some nights - both international and Kiwi trampers. Shep has been really happy so far with the respect and understanding trampers are showing for the lakes.”
Trampers are asked to make sure all gear has been cleaned and is completely dry before swimming or taking water from Lake Angelus and other tarns. There are no known control or eradication methods for Lindavia, so preventing its spread is a priority.
“As Lindavia is a microscopic organism, it can be spread to a new area in just one drop of water,” Sandra says. “Clothing, boots, drink bottles and swimming, tramping and fishing gear could harbour Lindavia which could then be washed out when entering a different lake or river.
“Lindavia is a tricky alga. It floats just below the surface and is hard to detect unless it multiplies in a bloom. When it’s not blooming, people won’t even know there’s contamination though the alga will be present.
It’s not known how Lindavia will affect the ecology and health of the lakes. It is not toxic to humans or livestock and poses no risk from food sourced from the lakes.
Only small amounts of lake snow have been seen in the Rotoiti and Rotoroa lakes to date, with Lindavia having been in the lakes a relatively short time.
