Algae blooms found at southeastern Lake Taupo swimming sites

Green algal mats visible at Whareroa South Beach. Photo / Supplied

More algae blooms have been found in Lake Taupo.

Waikato Regional Council staff have collected samples from algae blooms found during an inspection of southeastern Lake Taupo swimming sites this weekend.

Algal mats and surface-water bloom samples were collected from Kuratau Beach, Mission Bay, Motutere Bay, Hatepe, Halletts Bay and Whareroa South Beach.

The samples were analysed by regional council scientists todayto determine whether there were any toxic species.

The results were due to be reported to the Toi Te Ora Medical Officer of Health .

In the meantime, members of the public are urged to exercise caution and to avoid entering algae-affected areas.

These samples followed the closure of five popular swimming beaches at Lake Taupo on Friday and a warning from health officials that the toxic algae bloom could result in breathing difficulties.

A public health officer told a media briefing on Friday that contact with the phormidium algae could cause eye irritation, breathing difficulties if inhaled and stomach upsets.

"It also produces a neurotoxin, which causes tingling, numbness and difficulties with breathing," he said.

While the algae occurs naturally and blooms are triggered by warm-water temperatures and hot, settled conditions, it also feeds off nitrogen and phosphorus in the water.

Waikato Regional Council water scientist Dr Eloise Ryan said significant rain and cooler temperatures were needed to slow the algae growth.

"In my experience we won't see the bloom disappear ... If these conditions persist, we may see the recurrence of this bloom over summer."

Ryan said the algae might not yet be producing toxins but could do so at any time so the council would continue regular monitoring.

The water would be tested weekly, she said.

Medical officer of health Dr Neil de Wet said just because not all lake areas were listed as no-go zones, it did not necessarily mean they were safe, and people should be vigilant.

"Even in those areas of the lake where we don't yet have information or haven't yet issued a warning, be aware and look before using the lake because blooms can occur rapidly. It's important you check and if there's any visible algal material or any strange odour from the lake it's best not to use the water if there's any doubt."