18 May 2017

Govt to double spending on Otago lake weed

10:10 am on 18 May 2017

The government has offered to double the money it puts into stopping an invasive weed in Central Otago's Lake Dunstan if the regional council matches it - but one critic says that's still a drop in the bucket.

Lagarosiphon has infested Lakes Dunstan and Wanaka and is now threatening Lake Wakatipu.

Lagarosiphon has infested Lakes Dunstan and Wanaka. Photo: Weedbusters

Otago Regional Council and Land Information New Zealand (LINZ) are under public pressure to do more to stop the oxygen weed lagarosiphon, which has spread from Lake Wanaka to Lake Dunstan and is now threatening the near pristine Lake Wakatipu.

The weed is popular for home fish aquariums, and probably got established from dumping in the 1970s.

After months of public questions and criticism, the managers of the government's lagarosiphon control programme yesterday briefed regional councillors on progress.

Dave Mole said LINZ would put in $50,000, doubling its Lake Dunstan control funding, if the council would do the same.

Dave Mole said LINZ would put in an extra $50,000, doubling its Lake Dunstan control funding, if the council would do the same. Photo: RNZ / Ian Telfer

Land Information New Zealand's biosecurity manager, Dave Mole, told councillors those criticisms were largely unfair because the programme was going very well.

He said the $380,000 programme for managing the weed in Lake Wanaka was making good progress.

But Mr Mole recognised community concern, so came with an offer on Lake Dunstan weed control. He said LINZ would put in another $50,000 - doubling its present funding - if the council would invest the same.

Regional councillor Michael Laws, who has been on crusade on lagarosiphon, said it was good the problems were now out in the open - but nobody seemed to be doing anything, allowing the invasion to become inevitable.

He said the offer of an additional $50,000 was just a drop in the bucket and the council should be putting in millions.

"Here's an Otago Regional Council that has spent hundreds of thousands of dollars [stopping a handful] of wallabies, yet when it's got an exotic pest ruining the waters of Otago, it does nothing," said Mr Laws. "It defies belief," he said.

The programme has been fighting the weed with suction dredges, big cutters and, more recently, water-safe herbicides, but on current progress the waters will not be clear for decades.

Marcus Girvan wants a $1 million programme to get rid of lagarosiphon in Lake Wanaka.

Marcus Girvan wants a $1m programme to get rid of lagarosiphon in Lake Wanaka. Photo: RNZ / Ian Telfer

Project manager Marcus Girvan told councillors there was "not enough tea in China" to clear the waters of lagarosiphon right now, but with funding, new technology would make it possible one day.

He wanted a $1 million programme for the source of the problem, Lake Wanaka, tripling the current spending on that lake.

The council will consider funding of the Lake Dunstan programme in its annual plan deliberations next month.

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