A toxic algal bloom has been found in North Canterbury's Waipara River.

Traces of toxic algal blooms were discovered in dry watering holes.

With no rain in prospect the toxic algal levels were likely to deteriorate further.

The toxic algal species often multiply to high levels during periods of warm, sunny weather.

Kerry County Council has erected public warning signs of a potentially lethal toxic algal bloom.

The naturally occurring Red Tide phenomenon, which causes a toxic algal growth, almost ruined the industry.

A potentially toxic algal bloom was found on Lough Guitane in the Killarney Valley last week.

Its approach, in view of fish kills and toxic algal blooms, has been dishonest and harmful.

Last year GWRC said the upper Waipoua was not as prone to toxic algal blooms as the urban stretch.

People are being urged to avoid contact with a popular Queenstown lake due to concerns about toxic algal blooms.

Council defends its response Meanwhile, the Northland Regional Council is defending its actions over the potentially toxic algal bloom.

Monitoring had shown the amount of brown or black toxic algal mats growing on the riverbed had reached moderate levels.

Cyanobacteria are responsible for toxic algal blooms in lakes and rivers, and Cawthron Institute scientists are trying to better understand them.

A severe toxic algal bloom has been detected on the Waipoua River, which runs through Masterton - and it won't be helped by recent rain.

Warnings against using or drinking water from the largest of the Killarney lakes have been issued following the appearance of a potentially toxic algal scum.

It is hard to prove the exact causes of toxic algal blooms, but activists pose this formula: climate change + political inertia = cyanobacteria.