This week, thousands of fish died in the Hartbeespoort Dam, and investigations are under way to discover the cause of the mass mortality.
A terrible scene greeted members of the Ifafi Aquatic Club on Tuesday morning, with thousands of fish floating dead and dying among the hyacinths close to the shore. At the same time, the Schoemansville Oewer reported dead fish floating among the hyacinths close to the shore, and authorities and local fish experts were alerted.
Casper Kruger of Hartbeespoort Optimum Fisheries and Research rushed to the site and brought in an aerator to add oxygen to the water after a quick evaluation.
He assumed that the mass deaths were caused by a lack of oxygen in the water as a result of the dense hyacinth coverage.
“I have been in contact with Sefako Makgatho Health Sciences University to test water samples and perform tests on dead and alive fish.
“By late Tuesday afternoon, the situation seemed to be slowly improving, with fewer fish dying in the area of the aerator.
“There were fewer fish coming up to the surface and dying.
“I also found lice on some of the fish, something you usually find when their immune systems are compromised,” said Kruger.
According to Professor Julie Coetzee from Rhodes University’s Centre for Biological Control, oxygen deprivation seemed the most probable explanation.
She said she spoke to a scientist from the Department of Water and Sanitation, and his view was that the large numbers of dead fish pointed to a lack of oxygen in the water.
The DWS said it was aware of the recent fish deaths at the Hartbeespoort dam in North West and was collaborating with the Sefako Makgatho Health Science University (Medunsa) to investigate and analyse samples at the dam to ascertain the cause of the deaths.
Wisane Mavasa, spokesperson for the DWS, said a detailed statement would be issued once the investigation had been concluded.
“With regard to the hyacinth growth problem at the dam, the department recently appointed its entity, Magalies Water, to develop a resource management and remediation plan for Hartbeespoort Dam.
“The objective is to address the poor water quality in the dam’s upstream catchment, which leads to dam pollution, as well as minimise and control the algae and hyacinths that compromise water quality and dam use,” Mavasa said.