GENERAL SANTOS CITY (MindaNews/28 June) — Around P3.9 million worth of tilapia were destroyed in another major fish kill in lakes Seloton and Sebu in Lake Sebu town in South Cotabato.
Justina Navarrete, chief of the South Cotabato Office of the Provincial Agriculturist (OPAG), said Tuesday the fish kill occurred in portions of the two critical lakes in the last three weeks, with the onset of almost daily rains in the area.
She said it affected five fish cage operators situated in Sitio Lamsufo in Lake Sebu and one in Lake Seloton.
The fish kill, the fourth in Lake Sebu this year, destroyed around 4,000 kilos of tilapia in Lake Sebu and 320 kilos in Lake Seloton, she said.
“It was mainly caused by the sudden change of the weather in the area,” Navarrete said.
She was referring to “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.
Rex Vargas, OPAG’s fishery coordinator, said the phenomenon occurs when cold rainwater, which is heavier than warm water, settles at the abyssal zone of the lake.
“This 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,” he explained.
Vargas said 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.”
In April and May, around 10,800 kilos of tilapia were destroyed in a series of fish kills blamed on “kamahong” in lakes Sebu and Seloton. The municipal government reported the first fish kill in January.(MindaNews)