Lindavia intermedia was discovered in Lake Waikaremoana in 2008 and it has now been confirmed in Lake Taupō. Further investigation has indicated it is also present in Lake Rotoaira.
Waikato Regional Council is collecting and testing water samples collected from hydro lakes downstream from Lake Taupō, as well as Lake Rotongaio.
While other waterways may also have Lindavia intermedia, rivers and streams with fast moving flows do not provide an ideal environment for the algae to thrive.
Lindavia intermedia is an extremely small algae species that floats in water and has the potential to create lake snow.
In the scientific world Lindavia intermedia is known as a diatom, meaning its cells are made out of silica.
There are an estimated 100,000 different types of diatoms world-wide. With so many different species it isn’t possible for scientists to study them all in great detail. Lindavia intermedia is one of the less researched species, so we know comparably very little about it.
Like all diatoms, Lindavia intermedia is microscopic. It’s smaller than the width of a human hair and it’s therefore difficult to detect its presence in lakes unless specific tests are carried out.
Lindavia intermedia poses no risk to food sourced from lakes, and there are no human or animal health risks. There is currently no known impact on the health of lakes.
Councils are working with stakeholders and researchers to find out more about what conditions influence the growth of Lindavia intermedia. In particular, we are keen to understand what causes it to produce lake snow like it has in some South Island lakes.
Lake snow is sticky and looks like strands of mucus or slime “hanging” under the water.
Lake snow may be found by members of the public as slime on fishing gear and boat hulls. It could also cling to them when swimming. It can clog boat filters, as well as industrial and domestic water supply filters.
Researchers don’t know for sure what causes Lindavia intermedia to produce lake snow. What we do know is that it’s likely to have been in these Waikato and Manawatū-Whanganui region lakes for more than a decade. Over that time, it has not produced lake snow and we have no evidence of it causing issues.
There is currently no known way of removing Lindavia intermedia or lake snow once it is present in a lake. Our aim is to prevent the spread.
NIWA research for lake snow presence in the South Island identified that methods used in Clean, Check, Dry are appropriate for use with lake snow.
You can help to protect your favourite waterways if you always check, clean, then dry any equipment that comes into contact with the water, between every waterway, every time.
Drying can be used as stand-alone treatment for non-absorbent items if you take great care to:
Report anything that looks like lake snow to the Ministry for Primary Industry’s pest and diseases hotline: 0800 80 99 66.