The green algae-like spots that have been spotted for the past few days on the surface of Sungai Melayu near here have raised fears among the fishing community and local residents. Fishermen claimed they have experienced itchiness after getting in contact with the water, drawing the conclusion that it gave a side effect to humans.
Here are the things you need to know about the algae in Sungai Melayu:
Diatom Algae Bloom
It has been confirmed by the Johor Fisheries Department director Noraishah Hashim that the algae is diatom algae bloom. Noraishah told a local newspaper that the algae bloom covered an area of about 10km from the Pendas waters up to Sungai Melayu.
She said the phenomenon is called eutrophication from the initial observation, which happens when there is an enrichment in the water body of nutrients involving that sort of algae.
“It is an algae (plankton) bloom where it is (possibly) due to agricultural, domestic sewage or seabed dredging contamination or marine recycling work.
In addition, if there is a dramatic weather change, the bloom of algae may also occur. It can also arise from the enrichment of nutrients in the water body,” she told reporters after the algae bloom location inspection.
Noraishah said a water sample had been taken for analysis on the algae and water quality in the area to identify the cause of the incident as well as its impact on the environment.
“We have sent the sample to the Batu Maung Fisheries Research Institute, Penang while the sample to find out the water quality had been sent to Gelang Patah Fisheries Research Institute, here in Johor.
“The results of the algae will be known within a week, while the results of the water samples may be ready tomorrow or the day after,” she said.
Is it Harmful to Humans?
As regards the fishermen’s argument that the water containing the algae has an impact on humans, such as itching, Noraishah claimed that the algae was not harmful to marine life as a result of preliminary findings, but its effects on humans had not been determined yet.
Diatom algae are usually regarded as harmless (to marine life); although the dissolved oxygen content can decrease and cause the death of fishes.
“We have advised the fish-farmers around here to sell their products, such as fish that have reached the size required to be marketed or to install a blower to increase oxygen levels at night,” said Noraishah.
She said it could take a week or two for the algae bloom to vanish from the waters. The region currently has 106 marine fishermen, 20 mussel breeders and six caged-fish breeders.