Algae growth turns Pertang River green, says Fisheries Dept

The Negri Sembilan Department of Fisheries (DOF) has reported that excessive algae growth in the Pertang River, located in Mukim Pertang, Jelebu, has caused the water to turn green. This phenomenon was attributed to the prolonged hot weather and lack of rainfall, according to Kasim Tawe, the DOF director. The green algae growth in nearby fish ponds was responsible for the color change, rather than pollution, Tawe explained.

The DOF has been actively monitoring the area, as the impact of algae growth on fish populations can vary depending on the density and species of fish present. Under controlled conditions, the algae serves a beneficial purpose, providing dissolved oxygen, acting as a natural food source, and improving water quality. It also acts as a natural shield against the sun's rays, reducing stress on fish.

However, uncontrolled algae growth can lead to a rapid drop in dissolved oxygen levels, especially at night, and cause sudden fluctuations in water pH, which may result in clogged fish gills. Fish breeders are advised to take several measures to control algae growth, such as using waterwheels at night, gradually changing the water, reducing feeding, installing shading nets, applying probiotics, and lowering the fish population in the ponds.

The 29.54-hectare former mining pond, which is utilized for breeding baung, red tilapia, and Lee Koh fish, is currently being closely monitored by the Jelebu police and the Jelebu District Fisheries Office to maintain the situation under control.