Following the detection of an algal bloom in Waituna Lagoon, Environment Southland is advising the public against swimming, fishing or taking seafood from the lagoon.

The algae is still being tested to determine whether it is toxic or not, but Environment Southland is encouraging a precautionary approach in the meantime.

This represents the second algal bloom warning issued in as many days by Environment Southland, after the toxin was found on Tuesday (9 Jan) at the dam on the Waihopai River.

Team leader aquatic ecosystems Ash Rabel says there are species of toxic algae (planktonic cyanobacteria) present within the lagoon, but the actual species and the total biovolume will need to be confirmed by the Cawthron Institute following testing of samples taken on Wednesday. 

“Samples have been sent and we have asked for these to be processed promptly.” 

Toxic algae poses both human and animal health, and ecological risks. It’s difficult to see, but the water might be cloudy, discoloured, or have small greenish globules suspended in it. 

You should always assess the situation carefully before you or your dog enter the water. It is better to be cautious and avoid the area.

The Waituna community has been communicated with directly about the situation. 

“High toxic algae levels combined with the high phosphorus and nitrogen levels indicate we will need to keep a close eye on the ecological health of the lagoon.

“While we await key results, we will increase sampling frequency to ensure any changes are quickly picked up on. 

“Once we have the results we will be able to confirm public health warnings around interactions with the lagoon. 

“In the meantime, we urge the public to avoid swimming, fishing or taking seafood from Waituna Lagoon,” Ash Rabel says.