H

undreds of tons of fish, cultivated in floating net cages, or keramba, in Lake Maninjau, Agam regency, West Sumatra, have died following strong winds in the area.

'€œThe strong winds have driven sediment, such as sulfur, fish feed and household garbage, to the surface, or upwelling. While on full stomachs, the fish were hit by high levels of ammoniac, resulting in a lack of oxygen, which led to death,'€ Agam Regency Fisheries and Maritime Affairs Office head Ermanto said on Wednesday.

According to Ermanto, the phenomenon occurs almost every year, but the incident that killed tons of fish on March 13 was the first in the last three years.

'€œThe phenomenon could occur in other locations due to recent weather, that'€™s why we have urged all keramba owners to immediately harvest their fish before the weather changes,'€ he said.

As of Wednesday, most of the 175.5 tons of dead fish had been left to float in the lake.

The dead fish were found in one of the dozens of locations in Lake Maninjau where keramba can be found '€” in Koto Malintang, Tanjung Raya district.

The Agam regency administration has asked the keramba owners to bury the dead fish.

'€œWe have asked them to remove the dead fish because they are large-scale entrepreneurs who can afford to do so and they don'€™t have the permits to do business there. But as of Wednesday, only a few of them have done as asked,'€ he said.

The Agam regency administration, added Ermanto, had planned to take legal action against the entrepreneurs who failed to remove the dead fish.

The keramba, owned by 10 entrepreneurs from outside the area, are manned by local residents. The entrepreneurs were estimated to have incurred losses of at least Rp 3.5 billion (US$309,000), as the price of the tilapia and carp fish varieties could fetch Rp 20,000 per kilogram.

This is the third time such an incident has occurred this year. On Jan. 23 and 29, 11.5 tons and 10 tons of dead fish were found in the keramba, respectively. The presence of the keramba in Lake Maninjau has caused a serious problem in Agam regency. Currently, 15,000 keramba cages can be found in the 99.5 square- meter lake, producing 60 tons of fish, which are sold to Riau, Jambi and Bengkulu, while between 50 and 80 tons of feed are brought in from Medan, North Sumatra. The keramba owners, who hail from North Sumatra, Riau and Bukittinggi (West Sumatra), hire local workers to man their keramba. However, as none of them hold business permits, the regency administration earns nothing from their business. Local authorities, however, have been met with resistance from local residents during attempts to curb business.