Lake snot siren sounds

SHARE
Lake Snow... Some Wanaka fishermen say Lake Snow is clogging their gear and preventing them from fishing in certain parts of the lake. PHOTO:MARGOT TAYLOR

Otago Fish & Game has raised its serious concerns about invasive lake snot with the highest levels of Government.

Council boss Niall Watson has written to environment Minister Nick Smith and copied in Prime Minister John Key.

Watson wants the government to fund more research into the phenomenon, recently found in Queenstown’s Lake Wakatipu.

Otago University’s Dr Marc Schallenberg is conducting research into the lake goo – thought to be a clumping of bacteria, algae and mucus.

“But we now consider this issue requires a much bigger and more urgent response,” Watson says in his September 3 letter.

It’s not clear whether “lake snow” is developing because climate change, urbanisation, or if it “is a biosecurity incursion which warrants a didymo scale response,” he says.

Both offices have acknowledged receipt of the letter.

Lake snot has been in Lake Wanaka for about eight years, but more recently it’s been found in Lake Wakatipu and possibly Lake Hawea.

It was also detected in Canterbury’s Lake Coleridge in January 2015.

Watson says there needs to be a much greater understanding of what is going on “particularly if lake snow can be transferred from one lake to another by contamination”.

Lake snot is now clogging domestic water supply filters in Queenstown, along with motor boat cooling systems and anglers reels.

It is not a health concern, according to Queenstown’s council.

Watson describes the “two pristine alpine lakes” as important fisheries for trout and landlocked salmon.

He says with the surrounding land they “form a cornerstone for our international and domestic visitor industry” in the district.

Otago Regional Council’s Gavin Palmer says:

Mountain Scene went to Minister Smith for comment but he had not responded by deadline.

But in May the government announced a new Freshwater Improvement Fund of $100 million over the next decade to support initiatives to clean up New Zealand rivers, lakes and aquifers.

Fish & Game manage the country’s fish and game resources, issuing licences and protecting the environments.

Lake Hayes water quality is on the agenda next Saturday with residents planning to put the squeeze on new ORC councillors.

Councillors Maggie Lawton and Michael Laws are expected to attend the Friends of Lake Hayes AGM at the Events Centre, at 9am.

Schallenberg, who’s a research fellow in the university’s zoology department, and Fish & Game’s Helen Trotter will provide expert opinion.

Trotter, also an MSc student, is halfway through a study focused on algal blooms in the lake.

It’s different from lake snot but causes various problems for lake users.

Trotter says: “Lake Hayes and Lake Johnson have high nutrient levels compared to other lakes. It’s an historic problem.

“I’m still working through my samples and analysis so can’t draw too many conclusions but there are some interesting observations.”

Trotter’s looked at the layering of the lake, the algae, zooplankton [water fleas] and collected fisheries information.

“It’s those feeding relationships and how might we manage the fishery to enhance the grazing effect of the zooplankton on the algae to potentially mitigate the bloom.”

Trotter says Fish & Game’s recorded the lowest use of Lake Hayes by anglers in 20 years.

“People have maybe heard the lake’s not in good nick.”

Friends chairman Kerry Dunlop says he bought a $124 fishing licence last year: “And actually didn’t catch one fish.

“It’s certainly declined. There’s not been many fish caught in recent years.”

Dunlop says the algae can cover the lake in a rusty brown colour.

He says they’ve “been a wee bit frustrated” with ORC in recent years.

“But with these two new candidates and Jim Boult as mayor I think we’ll get some traction.”

Boult’s deputy chairman of the Friends.

The Friends plan to apply for funding through the Freshwater Improvement Fund, which could be used to apply a aluminium oxide to tackle the problem. That could cost up to $500,000. A monitoring buoy would be a further $75,000.

paul.taylor@scene.co.nz