Oxygen depletion causes massive fish kill in Lake Buhi,says gov’t fisheries agency


By Rhaydz B. Barica

LEGAZPI CITY, 25Aug2013 (PNA) – Thousands of fishermen in Camarines Sur were affected by the recent fish kill in Lake Buhi due to the depletion of oxygen and other environmental factors.

Over 1,000 fishermen in Buhi town affected by fish kill reported total losses of P 3 million.

Ranilo Leal of BFAR Bicol, said P 3 million worth of tilapia in Lake Buhi died a few days ago after the oxygen level in the lake was nearly depleted.

The latest fish kill occurred last Aug. 20-21, Leal said.

Fish kill in Lake Buhi, he said, occurs almost yearly due to poor oxygen supply and environmental degradation after the number of fish cage operators ballooned.

Data from the Buhi local government unit in 2007 showed there were 15,597 registered fish cages that occupied 226 hectares of the 1,707-hectare lake.

This number of registered fish cage operators is expected to become higher when proper accounting will be implemented by the LGU.

Data showed that over 90 percent of the lake has been occupied by fish cages, contrary to the 10 percent prescribed by law.

Lake Buhi has an area of 18 square kilometers, with an average depth of eight meters.

The lake lies in a valley formed by two ancient volcanoes — Mt. Asog and Mt. Malinao.

The lake is famous for its being one of the few bodies of water that contain the sinarapan (Mistichthys luzonensis), which is known as the world’s smallest commercially harvested fish.

Lake Buhi serves as the main source of livelihood for the residents of Buhi town,

Fourteen tributaries converge into the lake.

It supplies the National Irrigation Administration with water, irrigating at least 12,000 hectares in the Rinconada area — including the Municipality of Pili and Iriga City.

Historically, an episode of mass fish kill has been recorded in the lake but the worst took place in 1998, where the fish killed reached an estimated 25 million pieces of tilapia.

In 2003, a large fish kill that also hit the area and was blamed on sulfur contamination.

The fish kill is locally called by the fishermen in Buhi as “kanuba” for the sulfur smell that accompanies the phenomenon.

The Kanuba is traced to upwelling, a sudden influx of warm water in the lake.

The problem of oxidation, however, cannot totally be ruled out.

The area has a slight problem with agricultural run-off but the biggest source of anxiety for the municipality is the unmitigated proliferation of fish cages.

In 2010, another fish kill was reported due to almost depleted oxygen levels.

On Aug. 20, Ermie Mora, BFAR laboratory division chief, reported that the oxygen was almost depleted and, aggravated by Typhoon “Maring,” triggering the fish kill. (PNA)


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