Cause of  Hartbeespoort Dam fish death still unknown

By Molaole Montsho

The cause of mass fish death in the Hartbeespoort Dam near Brits is not yet known.

Masses of fish were found dead at the canal of Venice Village Estate, in the Hartbeespoort Dam area on October 18. The dead fish were buried on an unoccupied piece of land.

Following the  incident, Magalies Water team responded promptly by collecting water samples on October 22 the following day Magalies Water, together with the department of water and sanitation (Enforcement and Compliance) and the Madibeng local municipality, conducted a site inspection.

“No visible signs or evidence was found to indicate the cause of the fish kill, and water quality results did not reveal any abnormalities in the sampled water. As the incident was reported three days after it occurred and water quality conditions can change rapidly, we urge the community to report fish kills immediately to Magalies Water and the department of water and sanitation, as well as any accompanying visual evidence of the affected fish and the exact location,” said Magalies Water spokesperson David Magae.

“To date, we have recorded only one fish kill case at Venice Village Estate.  

While this incident is cause for concern, and can cause public panic, Magalies Water advises communities to ensure that they monitor all developments pertaining to the water safety of the Hartbeespoort Dam through official communication issued by the department of water and sanitation and/or Magalies Water.”

Magae said since this incident, they continue with regular sampling of the raw water in the precinct of the dam, and to date no further abnormalities have become apparent.

“It is common cause that the current situation of the growth of the hyacinth and salvinia have an adverse effect on the amount of oxygen on the waterbody which can also result in the death of other aquatic species, such as the fish found in the dam.”

He said Magalies Water has previously commented publicly on the high levels of loaded pollutants that enter the dam which also contributes to the sprawling growth of the hyacinth water plant, which brings about other challenges in the preferred conditions of the raw water in the catchment and dam.  

“Work continues despite these challenges, and the department of water and sanitation together with stakeholders are regularly updated on all interventions, challenges as well as mitigation measures which are designed to stall the speed at which the invasive plant is spreading over the dam.”

In 2023 investigations conducted by the department of Water and Sanitation revealed that the fish that died on April,11, at the Hartbeespoort Dam, was due to extremely low oxygen levels in the dam.