Fish cage operators in Taal Lake were advised by experts to harvest tilapia now as the level of dissolved oxygen continues to go down, threatening to cause extensive damage to the aquaculture sector in the area.
“We are still monitoring because the fish kill is still going on in some areas,” said Elmer Bascos, Batangas Provincial Environment and Natural Resource Officer (Penro) and concurrent Protected Area Superintendent (PASu) of the Taal Volcano Protected Landscape.
Bascos said dissolved oxygen level will continue to cause fish kill until the end of the month as they expect the situation to improve only in July.
“They should harvest now. The problem with some fish cage operators, they want to maximize income by letting their tilapia grow bigger, to gain more weight,” he said, belying allegations that the number of fish cages in Taal Lake had exceeded its carrying capacity.
“The carrying capacity of Taal Lake is 6,000 fish cages. The current number of fish cages is below the carrying capacity,” he said.
Because of the incident, Bascos said he will recommend limiting the operation of fish cages to at least once a year, avoiding the months of May and June, or the period during which dissolved oxygen goes down in the lake, resulting in massive fish kill.
According to Bascos, as early as May, fish cage operators have been warned by the Bureau of Fisheries and Aquatic Resources (BFAR) about the alarming situation in Taal Lake as they monitored that the dissolved oxygen in some areas in the lake have already gone down.
According to Bascos, fish kill in Taal Lake happens seasonally, during the months of May and June, as the dissolved oxygen goes down during the period.
“They [fish cage operators] know this already. Every year, in May and June, dissolved oxygen in the lake goes down that is why they are told to harvest before this happens,” he said.
According to BFAR, dissolved oxygen should be 5 parts per million. However, the level of dissolved oxygen went down to as low as 2.8 ppm, resulting to the massive fish kill, as the dissolved oxygen went as low as 0.52 ppm at the bottom and 0.86 ppm at the surface.
As of June 1, a total of 605 metric tons (MT) of tilapia were lost to the fish kill. The damage could easily cost around P50 million.
According to DENR Regional Executive Director Maria Paz Luna, a total of 121 fish cages in Barangay Buso-Buso and Gulod in Laurel, and Barangay Banaga in neighboring Agoncillo town were affected.
The Pambansang Lakas ng Kilusang Mamamalakaya ng Pilipinas (Pamalakaya) blamed the excessive number of large fish pens for the fish kill in Taal Lake.
In a statement, Pamalakaya said that this was the third fish kill to hit Taal Lake since last year, citing the same incidents that happened in November 2018, which affected 60 MT or equivalent to P5-million worth of tilapia, and last January that killed 99.8 MT of fish.
“Fish kill is becoming the norm in Taal Lake courtesy of unsustainable aquaculture practices, which include the incessant drive of fishpen operators to increase the number and size of aquaculture structures beyond the carrying capacity of the lake. And its adverse effects are getting worse day by day, which can be seen on the increasing volume of fish killed every time this phenomenon occurs,” Fernando Hicap, Pamalakaya National chairman said in a statement.
“This is not a simple natural phenomenon as claimed by the authorities, but (the) ecological disturbance caused by the monopolization of the aquaculture industry in Taal Lake without consideration of its limit. Intensification of aquaculture demands higher feed intake, which leads to hypoxia or oxygen depletion due to unregulated nutrients and bacterial loading” said Hicap.
The fisherfolk group recalled its demand to dismantle vast tracts of fish pens in Taal Lake owned by private individuals and big fishing firms, order operators to comply with the lake’s carrying capacity, and prioritize the fishing rights of small fisherfolk who have been deprived of their traditional fishing grounds due to the privatization of the fishing water.