BFAR explains causes of Metro Manila fish kill

October 11, 2019
Fish kill
Workers collect thousands of dead fish among rubbish that washed ashore on Freedom Island, a protected area for migratory birds, along Manila Bay on October 11, 2019. An agriculture department official said the government suspects the fish kill was caused by water pollution on Manila Bay, one of the most polluted waterways in the country. / AFP / Ted ALJIBE

THE  fish kill in the coastal areas of Las Piñas and Parañaque was not caused by blast fishing but from the poor level of oxygen and high levels of ammonia and phosphates in said water body.

Based on the tests conducted by the Bureau of Fisheries and Aquatic Resources-National Fisheries Laboratory Division and BFAR 4A on the water quality in three sampling areas, it showed that there is a poor level of dissolved oxygen and higher levels of ammonia and phosphates than the standard level.

The  sampling areas were in San Dionisio and Bay City, both in Parañaque.

In a statement, the BFAR said that the standard level of dissolved oxygen is 5.0 parts per million (ppm) but based on the results, the level of dissolved oxygen in San Dionisio was recorded at .70 ppm while in two sampling, both in Bay City, they were recorded at 2.00 ppm and .70 ppm, respectively.

The standard level of ammonia and phosphates, on the other hand, are 0.05 ppm and 0.5 ppm, respectively, but based on the results, the level of ammonia and phosphates recorded from San Dionisio area were at 3.51 ppm and 6.45 ppm, respectively.

The levels of ammonia and phosphates from the two sampling areas in Bay City were recorded at 1.29 ppm, 1.68 ppm (ammonia) and 7.11 ppm and 8.28 ppm (phosphates), respectively.

The BFAR said that ammonia is a chemical compound produced naturally from decomposing organic matter, including plants and animal wastes.

It added that the ammonia in the water supply might have also come from agricultural, domestic and industrial wastes.

Phosphates, on the other hand, is one of the primary material sources for many forms of algae and could come from sources like domestic sewage and runoff from agricultural land, urban areas and green areas.

“These chemicals at high levels may cause detrimental effects which may result in fish kill,” the BFAR said in its statement.

According to BFAR, the fish kill resulted in the loss of an estimated volume of one to two tons of fish which consists of bagaong, bakule, sapsap, tilapia, bakoko, siliw, manabon and barakuda.

The BFAR said it is collaborating with the concerned government agencies for the continuous conduct of monitoring of water quality in the area.

It will also provide technical assistance to the local government units of Las Piñas and Parañaque in the implementation of necessary management measures during fish kill occurrence such as proper disposal of dead fish.

“This is to ensure that dead fish will not reach the market and prevent sanitary-related diseases from happening,” the BFAR added.