GENERAL SANTOS CITY -- The Municipal Government of Lake Sebu in South Cotabato is planning to declare the area under the state of calamity due to another major fish kill that already destroyed around P6.5-million worth of tilapia.
Zaldy Artacho, Lake Sebu municipal agriculture officer, said Tuesday, January 31, that the ongoing fish kill started late last week in portions of the lake after its dissolved oxygen dropped to critical levels anew.
He said the phenomenon, known locally as “kamahong,” came after almost a week of sporadic heavy rains in the area.
Artacho said several fish cage operators initially reported on Friday afternoon that some of their tilapia appeared gasping for air.
"By night time, the fish kills already started in a number of fish cages," he said in a radio interview.
Citing their initial assessment, Artacho said a total of 72,335 kilos of tilapia have been destroyed as a result of the incident.
The prevailing farm gate price for tilapia in Lake Sebu is P90 per kilo.
Artacho said this figure only came from 19 affected fish cage operators in Barangays Poblacion and Takonel.
He said the validation and assessment is ongoing for the other affected fish cage operators. It was earlier estimated at more than 300.
Some operators were forced to conduct massive emergency harvests over the weekend in a bid to save the remaining tilapia, he added.
As a result of the incident, Artacho said Mayor Antonio Fungan ordered their office and the barangays affected to prepare the necessary data for the declaration of a state of calamity.
The affected barangays were also ordered to to fast-track their calamity declarations.
Fishery officials had blamed the fish kills to 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, eventually causing a 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.
Last year, the Municipal Government of Lake Sebu recorded at least eight fish kills that destroyed around P1.4-million worth of tilapia. The major fish kill in the area was in 2014. (PNA)