Algae spread may be impossible to halt

Biosecurity New Zealand concedes it may not be possible to prevent the invasive algae didymo spreading throughout the country's waterways.

Biosecurity NZ's surveillance and incursion response manager, David Hayes, said after a meeting with Environment Canterbury yesterday that it was likely didymo, or rocksnot, would be found in other South Island catchments.

He emphasised that the Ministry of Agriculture and Forestry prime focus in attempting to contain the spread of didymo was educating the public to take personal responsibility for curbing the algae's spread.

"Whilst disappointing, it's not totally unexpected that we might get additional finds of didymo in the South Island."

Mr Hayes repeated that it was not known how the algae arrived in New Zealand or how long it had been here.

"In terms of managing the long-term issues of didymo and reducing the impacts, we also have a science strategy which is looking at ways that potentially could help reduce the impacts of didymo within the river systems," Mr Hayes said.

That work was continuing.

"We don't know what solutions we may find out of that research, but it's under way at the moment."

The meeting yesterday was called after reports that several areas in the lower reaches of the Waitaki River in South Canterbury had become infested with didymo.

Also at yesterday's meeting were representatives from Meridian Energy, which has expressed serious concern about the possible effects of the algae on its hydroelectric canals and turbines on the Waitaki River.

Fish and Game central South Island spokesman Jay Graybill said the issue affected more than just recreational water users.

His organisation had issued a "clear message" to anglers that it was not the time to be complacent about the algae's spread.

It was essential to take all possible measures to stop it from reaching the North Island.

- NZPA