Health New Zealand has lifted the algal bloom health warning for the Ashley River at Gorge Bridge, following a reduction in potentially toxic algae levels.
Recent surveys indicated that the cover of benthic cyanobacteria, a type of potentially harmful algae, has fallen below levels of concern for public health.
Medical Officer of Health Dr Cheryl Brunton said monitoring by Environment Canterbury would continue until the end of summer and resume next summer when conditions are more favourable for cyanobacteria growth.
Cyanobacteria, often identified by its dark brown or black mats attached to rocks along riverbeds, can increase rapidly during warmer months. Growth is influenced by factors such as nutrient availability, stable low water flows, and warm weather. While high river levels can wash away algal blooms, detached mats can accumulate along the shore and pose a risk of exposure to toxins.
