Many fish die of asphyxiation

Damar Harsanto, The Jakarta Post, Jakarta

Fish in the waters around Gosong Sekati, Karya, Panggan and Pramuka islets in the Thousand Islands regency have died due to asphyxiation, according to an Environmental Management Agency statement on Monday.

Kakap (Lates calcarifer), Kerapu (Epinephalus tauvina), Pari (Elasmobranchii) and Sembilang (Plotosus sp) fish were among the species found dead on Friday around the four islets.

"The phenomenon was likely caused by a drop in oxygen content in the water due to a rapid proliferation of the phytoplankton population, which absorbs oxygen in the water," the agency's head Kosasih Wirahadikusumah told The Jakarta Post.

Kosasih said his agency had taken samples of the water from the locations and sent them to the laboratory of the Indonesian Institute of Sciences's (LIPI) oceanography for examination.

"Hopefully, the laboratory could come up with the result this week and we could know exactly what causes the deaths of the fish," he said.

Head of the Thousand Islands Marine Park Sumarto said that it had been occurring since Friday and was the third major case of its kind this year.

"I've observed that the occurrences are getting more frequent recently owing to a worsening of the ecosystem in the regency due to massive pollution from oil companies here as well as the massive waste that flows into the bay from Jakarta's 13 main," he explained to The Post.

Last year, the Jakarta administration reported at least five cases where amounts of fish, shrimp and clams died all at once.

Environmentalists have voiced suspicions that fish, shrimp and clams were being killed by high levels of pollution in the Jakarta Bay. Many have alleged that industrial plants located in the area had dumped unprocessed and toxic waste into the rivers or into the sea directly. However, not a single case to date has been heard in any courts in the capital.

Worse still, for many Jakarta residents, rivers also serve as sewage canals as there is an absence of an integrated sewage system in the city.

Last year, the Center for Marine and Coastal Natural Resources Study at the Bogor Agricultural Institute (IPB) revealed that the heavy metals found in Jakarta Bay had exceeded tolerable levels.

The lead (Pb) content stood at 0.120 milligram per liter, much higher than the standard level of only 0.008 mg per liter, Cadmium (Cd) hovered at 0.068 mg per liter compared to the standard level of 0.001 mg per liter, while Mercury (Hg) was at 0.005 mg per liter, higher than the tolerable level of 0.001 mg per liter.

According to Sumarto, the dead fish phenomenon often takes place after real heavy rains wash a lot of the scum and pollutants into the sea.

"So far, there have not been significant improvements made by the administration to reduce massive waste dumped into the city's rivers," he acknowledged.

He said that the management of the Thousand Islands Marine Park also discovered a spill of palm oil about a 100 meters off the coast of nearby Tanjung Priok Port in North Jakarta.

"The spill was 200 meters in width and 1.5 kilometers in length. But, I think that spill is unlikely the cause (of the deaths of the fish)," he said.

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