Mass die off of fish in fish farms of Jakarta, Indonesia
Mass death of fish in the reservoir allegedly caused water pollution leading to a reduction of dissolved oxygen (Dissolved Oxygen / DO).
Pollution of the waters of the reservoir is not only due to the existence of floating net cages exceed the carrying capacity of the environment, but because it is a downstream reservoir watershed that has been contaminated by sewage.
Floating net cage fish farmers (KJA) in waters Cirata, West Java, helm obtain weather forecast information hostile conditions the next few weeks. The Meteorology, Climatology and Geophysics (BMKG) predicts the peak of the rainy season occurs early January to February 2015.
Learning from the experience of previous years, entered the peak of the rainy season means it will appear threat of mass death of fish (KMI) in waters Cirata. Signs before the events of the IMA, usually cloudy sky for a few days with the wind.
Therefore, these days most of the farmers did not dare to speculate with the weather conditions. “Because the weather is getting a bit ugly, some farmers to harvest fish early KJA. There are also farmers who plant the seeds reduce fish so great loss, “said fish farmers KJA, Maman, told The Jakarta, last week.
Farmer losses could reach millions of dollars for failing to harvest fish cultivation KJA. Head of the Regional Office Technical Implementation Unit (UPTD) Aquaculture Fisheries Development Center Public Bodies Cirata, Ade Durahman, giving examples of November occurred KMI around 153 tonnes due to the quality of water decreases dramatically.
Of the total of KMI, which absorbed about 85 percent of the market price of six thousand dollars per kilogram. “Dead fish only sold six thousand dollars, whereas fish fresh condition can be sold up to 18 thousand dollars per kilogram,” said Ade, last week.
In fact, said Ade, dead fish could not have prices so the majority of farmers accidentally let it rot in the waters of the reservoir. This fish spoilage and polluting the waters thereby increasing the environmental burden in the reservoir.
“The carcasses of dead fish are left to rot in the waters of the reservoir can cause odor and make the water reservoir becomes rancid and slimy,” said researcher Associate environmental technology Agency for the Assessment and Application of Technology (BPPT), Nawa Suwendi, told The Jakarta, recently .
To prevent pollution of the water reservoir once the IMA, originally was published in West Java Governor Decree No. 41 of 2002 on Development and Utilization of Agricultural Land and Reservoir Region. KJA development in Cirata limited to 12 thousand plots. “In fact, now this number reached 53 thousand plots KJA,” said Ade.
Approach is difficult to apply the law, deception Ade, because Cirata wide. This reservoir has a total area of 7,111 hectares (ha) (including land) and a broad pool of approximately 6,200 ha. In addition, the presence of reservoirs in the three districts, namely West Bandung, Purwakarta, and Cianjur it difficult for enforcement.
When law enforcement does not work, the researchers tried to find the root causes of the IMA to offer a solution. KMI in Cirata allegedly caused water pollution leading to a reduction of dissolved oxygen (Dissolved Oxygen / DO).
Investigate a investigate, water pollution Cirata not only due to the presence of KJA which exceeds the carrying capacity of the environment, more so because Cirata is downstream of the flow of water from the River (Citarum and Cicendo) actually has contaminated domestic and industrial waste in the form of organic materials and inorganic.
“The level of pollution of the waters of the reservoir influenced their activities in the upstream watershed (DAS) that goes into the reservoir and the activity in the reservoir itself,” said Nawa. The effects of increasing pollution of reservoirs in the form of organic load and downs of the carrying capacity of the environment may cause a reduction in DO.
DO condition that usually gets worse when the weather is less friendly. Nawa explain the rainy season like now it will affect the discharge of rivers that flow into the reservoir to be able to cause the flow pattern in the waters of the reservoir. Flow pattern in this reservoir can cause the spread of pollution and sediments in the reservoir teraduknya.
“Teraduknya reservoir bottom sediment (organic matter) can interfere with the process of photosynthesis in aquatic organisms resulting in lower levels of DO,” said with a doctorate from the University of Indonesia.
Decreased levels of DO in the rainy season, said Nawa, compounded when the winds blowing parallel to the coast resulting in flows perpendicular to the coast, causing upwelling. Occurrence will result in the lifting of the upwelling of nutrients that exist in the base to the surface. The high nutrients in the surface can lead to hinder the process of photosynthesis organisms that live in the waters.
“Disruption of the process of photosynthesis means that inhibits the production of oxygen in aquatic organisms,” explained Nawa. The process of photosynthesis is also disturbed when clumps of clouds covering the sun rays to the Earth’s surface.
Nawa continue lasting cloud cover also affect the temperature of the air at the surface. The surface air temperature would then affect the temperature of the water reservoir, causing reduction in DO. “Reduced DO is what causes the IMA,” said Nawa.
Based on the research Nawa, KMI in Cirata in a year can occur more than once. In addition to the environmental impact, a negative impact on the economy KMI KJA owners who lost their capital and workers who have lost their livelihoods.
The collectors and fish traders are also affected because they could not sell. In the end, the supply source of protein ordinary people who eat fish also disrupted.
Cirata fish production, said Ade, so far to supply the protein source community in West Java, Central Java, and Jakarta. “Cirata fish production reached 240 tons per day,” he said.
Therefore, Nawa KJA suggested that fish farmers should not lose money in producing fish farming remains the balance between environmental, economic, and social. The balance of these three aspects are the pillars of sustainable development.
That is, when building a fish farming business KJA still consider the carrying capacity of the environment to the economy they are not disturbed because acaman KMI. No less important than that, the supply of protein for fish consumption did not break down.