Cyanobacteria Toxic Algae

Cyanobacteria, more commonly known as 'toxic algae', are naturally present in New Zealand river waterways, lakes and marine water. It only becomes a problem when an increase in high concentrations forms blooms. Not all cyanobacteria species produce toxins, which can be potentially fatal if ingested. It is found living on the bed of rivers and lakes and in the upper reaches of estuaries, but can also occur in slow-moving water in rivers.

Toxic algae is generally found in clean water but can grow when river flows are low and stable and temperatures are consistently warm. Planktonic ('floating') cyanobacteria is present all year in lakes and coastal waters but generally increases over summer with warmer temperatures.

Council routinely monitors its cyanobacteria levels at recreation sites on the Maitai and Wakapuaka rivers, as well as Poorman Valley Stream in Isel Park. 

CURRENT ALERT LEVEL IS GREEN (low risk) for MAITAI at AVON TERRACE

Check weekly council monitoring and alert updates.

Please note that not all rivers are monitored. Please check out our Frequently Asked Questions and refer to our Fact Sheet for tips on identifying toxic algae. If you're swimming, check out LAWA's Can I Swim Here? website.