Poor oxygen levels caused fish kills: BFAR

However, BFAR said the ammonia in the water samples, “might have also come from agricultural, domestic and industrial wastes.” (File Photo By Bureau of Fisheries and Aquatic Resources (BFAR)/Wikimedia Commons, Public Domain)

MANILA – – Poor levels of dissolved oxygen and higher levels of ammonia and phosphates than the standard level caused the recent fish kills off the coastal areas of Las Piñas and Parañaque cities.

On Oct. 10, the Bureau of Fisheries and Aquatic Resources (BFAR) conducted an assessment after about one to two tons of dead fish were found floating off Las Piñas and Parañaque.

“The water quality test conducted in three sampling areas by BFAR’s National Fisheries Laboratory Division and BFAR (Region) 4A shows poor levels of dissolved oxygen and higher levels of Ammonia and Phosphates than the standard level,” BFAR said in a statement Friday.

According to its chart, dissolved oxygen should be greater than five parts per million (ppm) but tests showed it was only 0.70 to two ppm.

There was also a high level of ammonia at 3.59 ppm when it was supposed to be less than 0.05 ppm.

Ammonia is a chemical compound produced naturally from decomposing organic matter, including plants, animals and animal wastes.

However, BFAR said the ammonia in the water samples, “might have also come from agricultural, domestic and industrial wastes.”

Phosphates, on the other hand, are one of the primary nutrient 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 to the fish which may result in a fish kill.

Scientific examination conducted by the BFAR 4A (Calabarzon) Regional Fisheries Protection and Law Enforcement Group also showed that “fish mortality was not caused by blast fishing.”

The BFAR said it will continuously monitor water quality in the area and provide technical assistance to the local government unit of Las Piñas and Parañaque in the implementation of necessary management measures during a fish kill 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, it said.