Following the reported fish kill incident in Lake Buhi, the DA-BFAR Bikol’s Fisheries Integrated Laboratory Section conducted water quality testing for aquaculture use on July 24, 2024.
Twenty-four water samples were collected from the surface, middle, and bottom of eight stations in Lake Buhi (Salvacion, Cabatuan, Tambo, Iraya, Center of the Lake, Ipil, Sta. Cruz, and San Buena-Sta. Elena). Each sample was tested for dissolved oxygen (DO), temperature, transparency, total dissolved solids, salinity, and ammonia.
Based on the laboratory results, dissolved oxygen and ammonia were found to be at stressful levels for fish.
Dissolved oxygen readings ranged from 0.46 ppm to 5.16 ppm. Of the 24 samples collected, 23 had low DO levels. Normal DO level should not be less than 5 ppm.
Ammonia ranged from 3.57 ppm to 310.6 ppm, with all 24 samples exceeding the recommended range of 0-0.05 ppm for aquaculture use. This means the ammonia levels exceeded the recommended range by 70 to 6,000 times. Ammonia, a by-product of fish metabolism, is toxic to fish at stressful levels.
Overturn may have triggered the incident wherein during heavy rains, it brings upward low dissolved oxygen waters together with toxic by-products decomposition from the lake bottom.
In coordination with the LGU Buhi, it was reported that about seven tons of tilapia were lost to the fish kill since its occurrence on July 23, 2024.
BFAR Bikol reminds the public that it is not safe to eat tilapia or any other fish from a fish kill caused by high levels of ammonia. Ammonia toxicity can accumulate in the fish, making it unsafe for human consumption. Consuming such fish could lead to food poisoning or other health issues. Always ensure that fish are sourced from safe and uncontaminated waters.
It is also recommended that the fish carcasses be hauled and buried to prevent further deterioration of the lake’s water quality
(Source: BFAR Bicol)