The Bureau of Fisheries and Aquatic Resources (BFAR) on Wednesday said it has observed significant improvement in the dissolved oxygen and water transparency of Taal Lake, nearly a month after the reported sulfur upwelling in the area.
BFAR Director Asis Perez, citing reports from BFAR-4A regional office, said “the water quality in the lake which has been affected by the recent sulfur upwelling is now getting back to normal,” said Perez.
According to the report, two of four barangays in Talisay, Batangas that were affected by the recent fish mortality have already fully recovered from sulfur contamination.
The dissolved oxygen levels in Barangays Aya and Tumaway are 6.1 miligram per liter (mg/L) and 6.5 mg/L, respectively, which are higher than the 6.0 mg/L acceptable continuous exposure level in water for fish culture.
Barangay Quiling, on the other hand, recorded a dissolved oxygen level of 4.9 mg/L while Barangay Sampaloc’s is at 5.4 mg/L, both of which are above the 3.0 mg/L level in water associated with fish mortality.
“The current dissolved oxygen levels in barangays Quiling and Sampaloc in Talisay municipality have already improved and will not likely cause fish mortality,” Perez explained.
To recall, a blue-green discoloration of the waters associated with fish mortality was observed in the said barangays on January 17.
Of the 2,000 units of fish cages allowed for the town of Talisay, only 51 units in the four barangays had been affected, causing the death of 120 tons of tilapia and bangus combined.
Perez said the fish deaths were kept minimal by the proactive efforts of the different agencies concerned.
The lake municipalities, the fish cage owners as well as the fisherfolk were informed beforehand of the possible occurrence of sulfur upwelling during the cool months of November to February.
Fish cage operators were likewise advised to conduct emergency harvests of marketable sizes of tilapia and bangus.