BATANGAS CITY—The Bureau of Fisheries and Aquatic Resources on Tuesday advised fish cage owners to wait for the oxygen levels in Taal Lake to normalize before resuming operations.
A fishkill wiped out an estimated 800 metric tons of mostly milkfish on Friday and affected the towns of Talisay, San Nicolas, Angono, Laurel and Balite, as well as Tanauan City.
Authorities have blamed the onset of the rainy season, particularly the sudden drop in the lake water’s oxygen levels for the fishkill.
Rosario del Mundo, fisheries officer for BFAR, said fish cage operators need to wait until the dissolved oxygen (DO) level has increased to more than six parts per million (ppm).
She said water tests conducted on May 18, prior to the fishkill, showed the DO was 8.84 ppm but the oxygen levels were measured at 3.4 ppm after the fishkill.
“On May 29, the level was 3.7 ppm,” she added.
She said cleaning of the affected fish cages in the lake was still ongoing as of Tuesday.
In Talisay, Mayor Zenaida Mendoza said another 200 metric tons of fish were killed in Barangay Sampaloc on Monday.
“Right now, we are in the process of disposing the newly killed fish in the town,” she said.
Ginette Segismundo, provincial information officer, cited overcrowding of the fish as one of the contributing factors for the fishkill.
A fishkill was also reported on Sunday in Anda and Bolinao towns in Pangasinan.
“Fishkills usually starts with milky water forming in the upper section of the Kakiputan Channel. I have been observing this phenomenon for as long as I can remember. Milky white water, about a meter deep, forms before every fishkill. I have worked with fishermen and researchers and nobody can explain what causes it,” said Florante Garcia, chair of Bolinao’s fishery and agriculture management council.
The fishkill resulted in an initial loss of about 70 tons of bangus in Bolinao and Anda.
But Dr. Westly Rosario, head of the National Integrated Fisheries Technology Development Center in Dagupan City, said the milky water could be due to a substance released by seaweeds that die because of a decrease in water salinity and other factors. With a report from Yolanda Sotelo, Inquirer Northern Luzon