Bulacan fishkill damages tilapia ponds

BALAGTAS, Bulacan – Fisheries officials said yesterday that very low dissolved oxygen in water has caused the fishkill here over the weekend.

Camen Agustin, chief of the fish health section of the Bureau of Fisheries and Aquatic Resources (BFAR) in Central Luzon, told The STAR in telephone interview  that more than two hectares of tilapia fishponds were affected in Barangay Panginay.

The fishponds are being managed by farmers Oscar Madlangawa, Ricardo Martin, Rolando Gabriel and Greg Gonzalvo. Some 200,000 tilapia which were supposed to be harvested in three weeks time, were affected.

Last Thursday, the farmers noticed that tilapia in their ponds started jumping ouf of the water, a sign that there is low oxygen underwater.

The next day and until the weekend, the farmers said their tilapia stocks were all dead.

This led Agustin and other BFAR staff to conduct an investigation on Sunday.

Agustin told The STAR that they collected water samples in three different locations, two in a nearby creek and one inside the fishpond of Martin.

Based on initial BFAR reports, collected water from Panginay Creek have .06 dissolved oxygen, while water samples collected inside the fishpond and at the bridge near Inchem factory at the boundary of Guiguinto and Balagtas town have .94 and .61 dissolved oxygen, respectively.

Agustin said tolerable dissolved oxygen level should be five milligram per liter.

Low dissolved oxygen in water, she said, may be caused by water quality and abrupt change in temperature.

Agustin added that deterioration in water quality maybe due to discharges of waste water from households or nearby industries.