The Waituna Lagoon, situated southeast of Invercargill, is a habitat for native birds, fish, and plants. Recently, the lagoon was threatened by a toxic algae outbreak, known as a cyanobacterial bloom. To combat this, the lagoon was opened to the ocean in January.
Karen Wilson, the chief scientist at Environment Southland, stated that the lagoon is no longer experiencing the bloom. Recent tests show that the water quality has returned to normal. However, the full impact of the bloom won’t be known for a while.
This was the first time the regional council had to deal with a bloom of this size at the lagoon, so there are no previous data to compare the progress. Despite this, Wilson is hopeful that the lagoon will regain its ecological health over time, thanks to ongoing monitoring and collaboration with experts.
To gather more data, a high-frequency monitoring device was temporarily installed. The opening of the lagoon to the sea helped disrupt the bloom, but it also affected the rupia, an aquatic plant vital to the area’s ecology.
Nicki Atkinson, the Department of Conservation’s freshwater science lead, said that they are still waiting for the results of recent rupia surveys. She added that it’s important to protect the rupia’s growing season in the upcoming spring and summer.
One major issue affecting the lagoon is nutrient run-off from nearby farms. However, Atkinson noted that people are making efforts to reduce this problem. She emphasized the community’s concern for the lagoon’s condition.
In 1976, the Waituna Lagoon made history as the first area in the country to be recognized under the Ramsar Convention as a wetland of international significance.
