Results of trial months off

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It will be about three months before it is known if a trial using new equipment to remove lagarosiphon from Lake Dunstan could be deemed a success, people connected to control of the invasive weed say.
A long-reach excavator equipped with a rake attachment was used in the trial at the Kawarau Arm, near the Cromwell sewage ponds, on Friday morning. It was organised by the Guardians of Lake Dunstan.
Representatives of Land Information New Zealand (Linz), its contractor Boffa Miskell, Fish and Game, and the guardians attended the trial.
Linz biosecurity manager Dave Mole said results of the trial would be assessed in about two to three months’ time to gauge the level of regeneration.
‘‘Underwater photographs before the weed was removed have been taken and the area will be re-photographed by divers from the North Island.’’
The draft 10-year Lake Dunstan lagarosiphon management plan would also be launched at Clyde on September 2, although he could not say if there would be anyincrease to the $100,000 annual budget for control work.
The Crown-owned agency remained committed to controlling the weed at the lake’s high-value areas including swimming bays and boat ramps.
Guardians chairman Andrew Burton said he was pleased with the trial but would like it carried out in another part of the lake.
‘‘The area targeted was disgusting with so much mud and driftwood. It is estimated at the end of the three-hour period there was about half a metre of mud on the bank. We were meant to be hauling out lagarosiphon, not mud.’’