Kruger National Park rangers and conservation management officials have started draining operations at Silolweni Dam near Tshokwane Picnic Site today (Tuesday April 15, 2008) to prevent algal poisoning of the wildlife in the area.
KNP Rangers from Tshokwane first became aware of the situation at the dam when vultures were seen circulating on April 4, 2008. After investigation, five zebra carcasses were found and Tshokwane Section Ranger Mr Steven Whitfield suspected that blue green algae (cyano bacteria) was responsible for the deaths.
State Veterinarian Dr Roy Bengis, from the Department of Agriculture’s Veterinary Services confirmed that the animals died from algal poisoning after full post mortems were done on two of the carcasses. Water samples from Silolweni Dam confirmed that the water contained a high concentration of blue green algae.
“We understand that the large concentration of this algal poison was built up due to the high concentration of hippo currently found in the dam and we have found that the most effective way to discourage the hippos from visiting the dam is to lower the level of the water,” explained Dr Freek Venter, the park’s Head of Conservation Management.
Rangers were also concerned about the high populations of both black and white rhinoceros which often visit the dam and the decision was taken to burn the surrounding grass in an attempt to discourage grazing animals from visiting the dam until the draining operation began.
The pump apparatus will be visible from both the H1-2 tar road between Skukuza and Tshokwane and the tourist parking area near the dam itself. Silolweni Dam is very popular as a game viewing site and is visited by thousands of tourists every year.
“A number of options were considered before it was decided to drain the dam using floating pumps set up in the middle of the dam and, as this is the second case in the last 12 months where algal poisoning has caused multiple animal deaths, we are currently looking at permanent solutions to this problem,” concluded Dr Venter.
The Nhlanganzwane Dam near Crocodile Bridge Rest Camp was breached in July 2007 after it was discovered that the same algal poisoning had killed more than 54 animals.