By Allen Sam V. Estabillo
Workers haul their catch of clams and mussels in the late afternoon at the Navotas fish port in Manila on Tuesday. President Duterte is set to discuss rights and access of Filipino fishermen to the disputed West Philippine Sea during his visit to China on October 19-21.(MNS photo)
GENERAL SANTOS CITY (PNA) – Around 9,000 kilograms of tilapia were destroyed as another major fish kill hit Lake Sebu in South Cotabato.
Rudy Muyco, lake warden of Lake Sebu town, said Tuesday the ongoing fish kill started in parts of the lake last week as its dissolved oxygen dropped anew to the critical level due to the onset of the rains in the area.
Citing their monitoring, he said the decline in dissolved oxygen levels affected about 50 percent of the 354-hectare lake.
“At least 9,070 kilos of tilapia were so far destroyed because of the fish kill,” Muyco said in a radio interview.
The Bureau of Fisheries and Aquatic Resources in Region 12 earlier reported that 19 fish cages owned by nine operators in Barangay Poblacion were affected by the fish kill.
Muyco said other fish cage operators at the lake were forced to conduct emergency harvests to avoid further losses.
As a result, the price of tilapia from Lake Sebu in the local markets dropped to as low as PHP50 per kilo.
Lake Sebu Mayor Antonio Fungan clarified that the tilapia from the emergency harvests that are being sold in the markets are safe for consumption.
To address the fish kill, the mayor said he has ordered the continuous cleanup of water hyacinths in portions of the lake.
Fishery officials earlier noted that the presence of water hyacinths in Lake Sebu compounded the occurrence of “kamahong,” a phenomenon caused by the sudden rise in the water’s temperature.
“Kamahong,” which usually occurs during the rainy season, triggers the rise of sulfuric acid in the lake’s waters that eventually caused the massive fish kill.
The Office of the Provincial Agriculturist said the phenomenon occurs when cold rainwater, which is heavier than warm water, settles at the abyssal zone of the lake.
It causes the upturn or upwelling of warm water carrying silts, sediments and gases such as hydrogen sulfide, ammonia, sulphur and methane gas produced by the decomposing organic matter such as fish feeds.
Such situation results in the reduction of dissolved oxygen in the water, “forcing fishes to take in oxygen directly from the atmosphere and eventually die,” it said.
From April to June, around 14,000 kilos were also destroyed in a series of fish kills blamed on “kamahong.” The municipal government reported the first fish kill in January.