LLDA SETS UP MEASURES TO
PROTECT LAGUNA LAKE FROM FISH KILLS
Martin Antonio | April 25, 2011
Amidst the recent onslaught of fish kills in
Taal Lake and in Anda and Bolinao, Pangasinan, the
Laguna Lake Development Authority (LLDA) has set up
precautionary measures to secure Laguna de Bay, the
largest freshwater lake in the country, from fish kills.
Today the Environmental Quality & Research
Division (EQRD) of LLDA has conducted an
onsite inspection at the lakeside waters in
Pinagbuhatan channel and measured the amount
of dissolved oxygen (DO) in the area which
is currently at 5.7 to 6 milligrams per
liter (mg/L). This has passed the criteria
for freshwater bodies which need at least 5
mg/L of DO for fish to survive.
On Monday, June 6, EQRD will conduct a
series of tests in five major stations
distributed in the west, east and south bays
of Laguna de Bay as part of its monthly
monitoring to ascertain the water
characteristics around the lake.
The fish kills in Batangas and Pangasinan
were caused by sudden change in weather
conditions from a hot summer to rainy
season. When it rains, the surface water
temperature goes down and in turn forces the
hot water beneath to rise. This overturn
heats the fish pens thereby minimizing
oxygen supply and leaving thousands of fish
dead.
Compared to Taal Lake which has an average
depth of 100 meters, Laguna de Bay is very
shallow at an average depth of only 2.5
meters. The DO supply in Laguna Lake is
adequate since the oxygen available in the
air above the surface water easily
penetrates the bottom water.
Experts say that overcrowding in fish pens
may have significantly contributed to the
fish kills in Batangas and Pangasinan.
Hence, LLDA has sought the cooperation of
fish pen operators for a more religious
monitoring of the water condition in Laguna
de Bay.
Accordingly, LLDA will check if the fish pen
operators are following the aquaculture
requirements of the Bureau of Fisheries and
Aquatic Resources, that is, a maximum depth
of five (5) meters and a carrying capacity
of 10,000 pieces of fish per 500 square
meters.
In the past, most of the fish kill incidents
in Laguna de Bay were caused by “river
flushing” brought about by heavy rains
wherein pollutants and wastewater find its
way to the lake. The last one occurred in
July 19, 2010 right after typhoon Basyang
where heavy wave action and re-suspension of
sediments caused pollutive agents such as
garbage and wastewater to reach and
contaminate the lake water.
LLDA General Manager Rod Cabrera says that
the Authority has been doing a series of
river rehabilitation programs such as the
“Adopt-a-River” projects to clean up the
major tributaries which bring in pollution
to the lake. “The fish kills in Taal Lake
has caught our attention and we’re doing all
that we can to prevent this from happening
in Laguna Lake”, GM Cabrera firmly said.
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