Pollution is bigger threat, experts say

WHILE water hyacinth causes some problems, the fish in the Swartkops are more threatened by the pollution that the hyacinth absorbs.

That is the view of NMU fish ecology specialist Professor Nadine Strydom, who was commenting on the Department of Water Affairs-funded water hyacinth removal project.

“Sewage and heavy metals threaten our aquatic systems and indigenous fish like mullet, moonies and barbs. At least some of this pollution is absorbed by the water hyacinth,” she said.

Even if some removal of hyacinth had to take place, this should be done physically or via bio-control until a comprehensive study was done proving that the chosen herbicide was safe for other river life.

Swartkops Conservancy conservation officer Jenny Rump said they had called for some hyacinth to be left behind as the clearing was done in different areas.

“The pollution is our main problem and we know the water hyacinth absorbs it.”

Janine Adams, the director of the Institute for Marine and Coastal Research at NMU, said that while the hyacinth was causing problems in the Swartkops, the real culprit was the heavy pollution in the river and urgent steps needed to be taken to alleviate it.

“Water hyacinth is an alien invasive plant, so it is good it is being removed.

“But it is responding to the high nutrient input from the wastewater treatment plants upstream. If the water hyacinth is removed it will likely be replaced by another invasive plant because the river system is highly disturbed.”

Besides the Kelvin Jones Waste Water Treatment Works in Uitenhage there is another plant in KwaNobuhle and a third in Despatch,

“If the hyacinth is removed completely then toxic micro-algaes might take its place and these can threaten livestock and even human health if they are ingested,” Adams said. – Guy Rogers