Sulfur upwelling triggers fish kill in Taal Lake

MANILA, Philippines - Sulfur upwelling in Taal Lake has caused fish kill in four barangays in Talisay, Batangas late last week, according to the Bureau of Fisheries and Aquatic Resources (BFAR). 

Various fish species were found “gasping for air” along the shoreline on the night of Jan. 16. The following day, a blue-green discoloration of water was observed in the barangays of Aya, Quiling, Tumaway, and Sampaloc.

BFAR has been monitoring the phenomenon since 2000. Sulfur upwelling in Taal Lake usually occurs from November to February when the northeast wind disturbs the sediments in the lake, resulting in the upwelling of hydrogen sulfide, a poisonous gas.

Of the 2,000 fish cages in Talisay, 51 were affected. Production losses were placed at 70 tons for bangus (milkfish) and 50 tons for tilapia – valued at P10.5 million.

BFAR Director Asis Perez said fish cage owners and operators had been informed beforehand of the possible occurrence of sulfur upwelling during the cold months.

He said fish cage operators were advised to conduct emergency harvest of marketable sizes of tilapia and bangus.

Water pumps were also issued to fish cage operators to increase the dissolved oxygen level, which was deemed critical based on the water monitoring report, he said.

To ensure that the dead fish would not be marketed, members of Taal Lake Aquaculture Alliance Inc., Task Force Taal Lake, the Department of Environment and Natural Resources, the local governments concerned, and the BFAR have been monitoring and supervising their proper disposal.             – With Arnell Ozaeta