BALAGTAS, Bulacan – Fishpond operators here blamed waste water discharged from nearby factories as the main cause of massive fishkill over the weekend that affected around 20 hectares of tilapia ponds.
Rolando Gabriel, a former overseas Filipino worker, who had invested in fishpond operations in 1993, told The STAR that it is the first massive fishkill in the town.
He said that no less than 20 hectares of fishponds were damaged by hazardous water that overflowed on their fishponds last week during a heavy downpour that coincided with the rising sea water that inundated the low lying areas in this town.
“Before lunch, pumasok sa fishpond yung maitim na tubig at nagsimula ng magtalunan ang mga isda (Before lunch, black water entered the ponds and the fishes started jumping out of the water),” Gabriel said, noting that it is a sign that oxygen under the water is depleted.
Hours later, the black water that flowed into their ponds have literally killed their tilapia stocks, including the large breeder tilapia.
Gabriel told The STAR in an interview early Monday that many of his fellow fishpond operators suspect that hazardous waste water discharged from nearby factories as the cause of the fish kill.
They claim that there were factories along the Balagtas river that manufacture soaps and nails.
“Ang alam po namin, yung pabrika ng pako ay gumagamit ng asido para hugasan yung pako (What we know is that the nail factory uses acid or chemicals),” another distraught resident, who used to catch fish along the river during high tide, said.
However, this factory was not identified in the final report released by the Bureau of Fisheries and Aquatic Resources (BFAR) in Central Luzon yesterday.
Based on the four-page report obtained by The STAR, dissolved oxygen was extremely low at 0.75 milligram per liter while the ideal is 5 milligram per liter.
The report states that dissolved oxygen can be caused by decaying organic materials like garbage, and by sewage discharges from houses and commercial establishments along the banks of the river.
For this reason, BFAR recommended regular water quality monitoring of the river system considering a strata sampling from different stations.
“Certain environmental factors needed to be studied and analyzed for such factors are essential in the sound planning of inland water management,” BFAR recommended.
They also suggested that other concerned agencies must be requested to conduct their own regular water quality monitoring on the river for other important water pollution parameters crucial in drafting management plans for sustainable use of different rivers.