Hyacinth coverage on 14 January 2024.

Hyacinth coverage on the Hartbeespoort Dam is currently around 31.5% and according to the Rhodes Centre for Biological Control (CBC) almost all plants show signs of damage thanks to the hyacinth bug.
“The most recent water hyacinth cover measurement taken on 14 January 2024 was 31.47%. Water hyacinth cover exactly one year prior was higher at 43.28%. Monthly surveys of its biocontrol agent Megamelus scutellaris (water hyacinth hopper) indicate a rapid increase in their abundance since satellite rearing station releases of the agent resurged in August 2023. Since then, over 550 000 hoppers have been released by the nine satellite rearing stations located around the dam.
In January 2024 the average number of hoppers recorded from five survey sites was 2522 per m2. This number of hoppers is similar to the average recorded in April 2023, an abundance which caused the water hyacinth cover to start declining,” the CBC said this week.
Magalies Water spokesperson David Magae said the Hartbeespoort Dam’s Remediation Programme aims to maintain less than 5% hyacinth coverage on the dam. “The dam is acceptably clean and biogeochemical processes have improved. Nanobubble technology has been enacted to boost oxygen, sequestrate nutrients, retard the growth rate of aquatic plants, and improve the quality of the water. Traps are being installed to trap debris at the ingress of the Crocodile and Magalies Rivers as the premier natural water transfer conduits.” He did not elaborate on the hyacinth removal programme progress.
According to Matome Malatjie of Hya Matla, who is currently removing hyacinth from the dam, two weed harvesters are permanently on the dam. “We are running up and down, following the hyacinth. We are soldiering on,” he said.