Warning after potentially toxic algae found at Wainono Lagoon

6:42 pm on 4 December 2021

A popular fishing spot in South Canterbury has been declared unsafe due to the presence of potentially toxic blue-green algae.

Cyanobacteria blooming in shallow water near shore

Boiling the water does not remove the toxin, and fish and shellfish from the lagoon should be avoided (File image). Photo: File photo / 123rf

The Wainono Lagoon near Waimate is considered to be of national and international significance due to the high number of native fish and birds that live there.

Canterbury District Health Board's community and public health unit issued a notice yesterday, saying people and animals should avoid contact with the lagoon or drinking its water while the warning is in place.

The unit said boiling the water does not remove the toxin, and fish and shellfish from the lagoon should be avoided because they can concentrate toxins.

It said exposure to the algae (planktonic cyanobacteria) may cause skin rashes, nausea, stomach cramps and numbness around the mouth and fingertips.

Medical officer of health Matthew Reid said anyone who experiences any of these symptoms should visit their doctor immediately and let them know if you have had contact with the lagoon water.

Animals that show signs of illness after coming into contact with algal mats or scums should be taken to a vet immediately, and the vet told that they may have been exposed to algal toxins.

Environment Canterbury will monitor the lake weekly.