Lake snow link to Seattle algae

The algae has been identified in Lake Wanaka, Lake Hawea and Lake Wakatipu and other lakes in Canterbury and Southland. Photo/ODT files

No immediate measures will be taken to stop the potential spread of lake snow now scientists have found a genetic link between the organism in several South Island lakes and a lake overseas.

A report commissioned by the Otago Regional Council and authored by scientists from Landcare Research has found the algae which produces the lake snow mucus is highly likely to have been introduced to New Zealand.

Genetic testing of lake snow samples found specimens from all of the New Zealand lakes which have been identified as containing the algae were identical to specimens found in Lake Youngs, near Seattle, Washington.

The algae has been identified in Lake Wanaka, Lake Hawea and Lake Wakatipu and other lakes in Canterbury and Southland.

While it did not pose any health risks to humans, the slimy mucus constantly clogged water filters and fouled boat motors, costing residents and the Queenstown Lakes District Council hundreds of thousand of dollars each year.

The regional council's technical committee chairman Andrew Noone said a more intensive research programme could now get under way to understand the organism and work towards potential solutions to minimising the effects of lake snow.

At this stage there were no plans to introduce new measures to stop any potential spread of the slime, such as those put in place when didymo was discovered, Cr Noone said.

''It's not 100% certain yet but seems fairly clear this is an invasive species, but we still don't know how this has got into the country.''

It was clear the issue now needed to be headed at a governmental level with input from the regional councils, Cr Noone said.

The regional council would now work with Environment Canterbury, Environment Southland, and the Ministry for Primary Industries to identify appropriate ways to manage lake snow.

He acknowledged some residents in the Queenstown Lakes districts felt the council had been too slow in acting on the problem but wanted to reassure them it was heading towards finding a potential solution.

The report was the first in a series of studies designed to gain a greater understanding of the organism and the formation of lake snow.

Guardians of Lake Wanaka chairman and the Guardians of Lake Hawea member Dr Don Robertson said the study was a positive step in understanding lake snow but more research was needed to understand whether the organism could be controlled and if so, how.

''Maybe it's possible to manage, but given it's a fraction of the size of didymo and didymo has been very difficult to manage, despite a very active programme of check, clean and dry for the past 10 years, we will have to wait and see.''

Dr Robertson said comprehensive management and a monitoring programme was still needed on the health of the southern lakes, not just to control lake snow but also to understand and manage the overall health of the lakes and their catchments.