BATANGAS - The Bureau of Fisheries and Aquatic Resources (BFAR) on Tuesday warned fish cage operators in Batangas of a possible fish kill in Taal Lake due to the low levels of oxygen in three fishing municipalities.
Lea Villanueva, Assistant Regional Director of BFAR-Calabarzon, said they found out that the level of "dissolved oxygen" (oxygen beneath the lake) was "very low" off the towns of Agoncillo, Laurel and San Nicolas, all in Batangas.
Villanueva said that in April this year, the coastal town of Mataas Na Kahoy experienced a minor fish kill incident, where some 10 to 20 metric tons of fish died.
"With the rainy season fast approaching, overturns or resurfacing of decomposed materials and bacteria from the bottom of the lake can cause depletion of oxygen and will lead to fish kill," Villanueva explained.
Villanueva said the lowest oxygen level as of Tuesday morning was recorded at 3.2-4.7 parts per million (ppm). The ideal oxygen level is above 5 ppm for bangus (milkfish) farming in areas like the Taal Lake.
Villanueva advised fish farmers to conduct an emergency harvesting of their fish stocks that are already in their "harvestable sizes" and move their fish cages over to areas with higher oxygen levels.
"These naturally occurring phenomena are usually affected by temperature changes especially in the warm months of April to August and during the rainy months when typhoons occur," she said.
"We already sent a technical team to monitor the situation in the area and conduct regular advisory to the fish cage owners and their maintenance people about the impending fish kill."
Villanueva said the Bureau of Soil and Water Management of the Department of Agriculture has already lent water pumps and aerators last year to improve the quality of water in Taal Lake.
In 2011, fish kill incidents hit the towns of Mataas na Kahoy and Cuenca, as well as Lipa City, leaving at least 20 metric tons of milkfish and tilapia dead.