Cyanobacteria Signage for Waimea River

The Council is installing signage to warn of the presence of cyanobacteria (blue-green algae), which forms thick, dark brown mats, in Waimea River.

Cells within the thick cyanobacteria mats sometimes produce toxins that can be fatal to dogs and potentially harmful to humans, livestock and wildlife if a detached mat is swallowed.

Residents and visitors are asked to avoid contact with the water in the Waimea River. Dogs and livestock should also be kept out of the water for safety reasons.

River monitoring is also underway for the major rivers in the District. Most cyanobacteria will be washed away with the next substantial rainfall event.

If you are concerned about your animals, you should contact a veterinarian immediately. You or your vet can report any animal illness resulting from contact with the blue-green algae to the council.

Further Information

Information about cyanobacteria is available from the Customer Service Centre and on our website:

• Contact the Customer Services Centre
• Read more about toxic algae in our waterways

 

About Cyanobacteria
 

Cyanobacteria (also known as blue-green algae) is present in all streams and rivers and can grow to form thick dark brown mats under natural conditions, particularly in mid to late summer if the water flow is stable and temperature is warm.

The cyanobacteria mats are most prevalent, covering boulders in shallow riffle areas where it can readily photosynthesise.

If you swim your dog or take water for livestock or human consumption from the river, avoid contact with any thick dark brown cyanobacteria mats, particularly those that are easily accessible, exposed on river edges or floating in shallow areas of riverbanks or near rocks.

If cyanobacteria mats are widespread in a river you should presume that the water may be unsafe. Cells within the thick cyanobacteria mats sometimes produce toxins that can be fatal to dogs and potentially harmful to humans, livestock and wildlife if the detached mat is swallowed.

Please note that harmless freshwater algae (green and light brown forms) are also present in our streams and rivers over summer months.

Most cyanobacteria will be washed away with the next substantial rainfall event.

The public is encouraged to contact the Customer Service Centre if they require more information or have any concerns about water quality.