Ecological Disaster Threatens Photogenic Lake – Fish and Game

By DEUCHRASS, Andrea; in Queenstown

ONE of the most photographed lakes in the South Island is on the verge of a major ecological disaster, says Fish and Game New Zealand.

Picturesque Lake Hayes, near Arrowtown, has a history of nutrient poisoning from farm effluent and fertiliser run-off.

The Otago Regional Council tests the water quality every month and claims it has been improving.

But Fish and Game Wakatipu catchment officer Morgan Trotter said something had gone terribly wrong.

“I’ve probably seen about 30 to 40 dead fish and around 100 emaciated fish,” he said. “There are dead and dying ducks as well but we don’t know the true extent of the problem … the whole ecology of the lake appears to be under real threat.” Fish and Game was first alerted in December by members of the public who noticed a large algae bloom.

Residents had also reported seeing dead fish floating on the surface, he said.

“In a few weeks brown trout should start spawning but we are worried that they won’t have the energy to swim up and spawn,” he said.

While nutrification problems (where nutrients are poisoned) have been attributed to farmland that once surrounded Lake Hayes, leaking sceptic tanks might have compounded the problem, Mr Trotter said.

A catchment programme was needed to stop run-off from fertilisers and sceptic tanks getting into the lake, he said.

Fish and Game had made several complaints to the Otago Regional Council, which is responsible for the wider catchment.

“I just can’t understand how you can say the water quality is improving, when all those fish are dying,” Mr Trotter said. The Otago Regional Council, which also tests the in-flow from Mill Creek every month along with lake water quality, claims there are no major problems.

Otago Regional Council manager of resource science Matt Hickey said it had fielded complaints from Fish and Game about dead fish this season but he thought it was caused by the algae bloom early this year.

“We had a dry spring and a wet summer and the resulting bloom has a long effect over a few months.

It’s not just a one-off impact,” he said.

“We’ve just got to wait for the bloom to naturally disappear.” Algae blooms were common even in the most pristine lakes, he said.

“There is not anything unusual about our data this year.

“The monitoring of the water quality has shown a slight improvement.” The small size of the lake and land use around the catchment area made Lake Hayes prone to algal problems, Mr Hickey said.

——————–

(c) 2007 Southland Times, The. Provided by ProQuest Information and Learning. All rights Reserved.