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What to do with the fish pens in Laguna de Bay


By Dr. Emil Q. Javier

Dr. Emil Q. Javier

Dr. Emil Q. Javier

‘There are those who look at things the way they are, and ask why… I dream of things that never were, and ask why not?’  – Robert Kennedy

The order of the President to dismantle the big fish pens in Laguna de Bay while welcome to the ears of the thousands of fishermen in the lakeshore towns of Rizal and Laguna who depend on the open waters of the lake for their livelihood as well as to environmentalists who perceive aquaculture as spoiler of the environment raises a basic question on the place of aquaculture in our future.

We hope the order of the President was meant to merely regulate fish culture and not eliminate altogether all the fish pens and fish cages in the lake which supplies a significant source of the fish needs of Metro Manila. That will be unwise and myopic as this will adversely impact on the future of aquaculture upon which we have to increasingly rely for our fish needs as capture fisheries decline and stagnate over time with overexploitation.

It will be a mistake to look at the competition between fishermen and fish pen/fish cages operators in isolation as this is just as example of the intensifying conflicts between the needs of our growing population and expanding economy for food, water, energy and human settlements and their impacts on the state of our natural resources, health of the environment and welfare of our people. There are many other conflicts with impacts even more profound, longer lasting and potentially more divisive which need to be resolved with better science, more commonsense and a stronger sense of community.

Conflicts among competing users of laguna de bay

In fact, as far as Laguna de Bay is concerned, this is just the tip of the iceberg. In addition to the intramural conflict within fisheries (capture fisheries versus aquaculture), there is a looming worsening intense sectoral competition for water among fisheries, agriculture (irrigation) and water supply for domestic and industrial uses.

Each year towards the dry season as the waters of Laguna lake subside, and during high tide, seawater from Manila Bay intrude into the lake via Pasig River. The periodic intrusion of seawater is important to the ecology of the lake as sodium ions in salt water flocculate the negatively charged clay colloids in suspension in the lake waters. This phenomenon reduces lake turbidity, increases sunlight pentation and allows growth of more phytoplankton which fish feed upon.

However, salinization makes the lake waters less ideal for irrigation and water supply for drinking and industrial use. Thus to control intrusion of saltwater into the lake, the Napindan Hydraulic Control Structure (NHCS) was built in the 1980s over the objections of the fishery sector. Mindful of the adverse consequences of the NHCS on the primary productivity of the lake for plant growth and hence fish production, the fishery sector demands that the NHCS be left open most, if not all, the time.

Another continuing source of conflict is the need to protect the lower sections of Metro Manila from flooding during the rainy season. The engineering solution was to redirect the voluminous waters of the Marikina river into Laguna de Bay with the construction of the Manggahan Floodway (MF), which together with the Napindan Hydraulic Control Structure (NHCS) temporarily store/hold back the rising waters of Laguna de Bay until they could be gradually and safely released through the Pasig River.

While the two structures served the purpose of storing floodwaters in Laguna de Bay to prevent inundation of parts of the city, they shifted the burden to the lakeshore communities of Rizal and Laguna which suffered from higher and longer lasting floods.

A third even larger looming conflict is the plan to build a dike road to improve traffic flow in the southern part of Metro Manila as well as to protect the communities in the Rizal towns where the dike road will initially be built. The rest of the lakeshore towns, mainly in Laguna, are rightfully objecting because they will have to live with higher and longer lasting floods.

Fish pens as relatively minor, transient problems

Laguna de Bay serves several important useful purposes namely: 1) source of fish, 2) temporary storage of flood waters, 3) water for irrigating crops, 4) hydropower generation, 5) transport, 6) recreation and tourism, 7) increasingly as source of fresh water for households and industry, and  sadly, 8) a sink for wastes from all sources in the Laguna Lake basin.

For now the dominant use of the lake is for fish production. However if we come to think of it, the competition between catch fisheries and aquaculture while seemingly urgent politically is really relatively minor and transient compared with the broader, more complex, more contentious challenge of reconciling the overlapping, conflicting demands enumerated above. And more long-term, the challenges of abating water pollution and siltation which will finally kill the lake.

In the first place, artificial fish culture while far more productive need not completely displace capture fisheries. Both systems of production can co-exist and be justified on ecological and social equity grounds.

In 1973 when there were only 4,800 hectares of fish pens in the lake, milkfish production was reported at 19,200 tons or an equivalent yield of 4.0 tons fish per hectare per year. The catch of wild fish during the same period was 20,720 tons from over 85,000 hectares or an equivalent productivity of only 254 kilograms fish per hectare per year. These numbers need to be updated but the economic productivity advantage of aquaculture versus capture fishery is abundantly clear.

Nevertheless, there is a universally accepted concept of safe carrying capacity in the exploitation of natural resources beyond which the ecosystem deteriorates and its long-term productivity placed at risk. Obviously, it is foolhardy to convert all the 90,000 hectares of Laguna lake into fish pens and cages although it came close to that in 1984. Laguna lake  fish culture became so profitable that 51,000 hectares, more than half of the total lake hectarage, were converted into fish pens and fish cages. This provoked armed conflict between the small fisher folks who felt unjustly deprived of their traditional livelihood versus the big-time fish pen operators.

Government succeeded in diffusing the conflict by reducing the areas reserved for fish pens. The Laguna Lake Development Authority (LLDA DENR) which is mandated by law to regulate use of the lake proceeded to approximate the “safe” carrying capacity at 10-15 percent of the lake’s total area i.e. a maximum of 15,000 hectares. Ten thousand hectares were allocated for fish pens and 5,000 hectares for fish cages. These were embodied in a Laguna Lake Fishery Zoning and Management Plan (ZOMAP) of 1983, which was later revised in 1999 as a component of the Master Development Plan (MDP) for the entire Laguna de Bay region. The ZOMAP designated separate areas for fish pens and fish cages, fish sanctuaries and lanes for navigation.

The LLDA ZOMAP for Laguna de Bay is as good a plan as any and until and unless a better plan is developed, it is a matter of resolutely implementing the plan. The problems of constriction of navigation lanes and the location and identification of illegal fish pens and fish cages can now be easily enforced with GPS technology and aerial photography with use of drones.

The two outstanding remaining concerns are equity i.e. poor participation of small producers versus the large producers and the adverse of contribution of fish culture to the eutrophication of the lake.

As of 2006 the registered fish pens and fish cages covered 12,117 hectares and 998 hectares, respectively. Therefore by the ZOMAP plan, 2117 hectares of fish pens are illegal and therefore ought to be dismantled. More worrisome though is the gross undersubscription of fish cages i.e. 1,000 hectares actual us 5000 hectares planned.

Fish cages require less initial capital than fish pens and therefore more accessible to small producers. Government is morally obliged to provide conditions or incentives to facilitate broader participation of small fisherfolk in fish cage culture. Small fish cage operators need access to affordable credit and more organized marketing to get better prices for their fish. Government therefore ought to persevere in organizing and providing business and market support to small fishers’ cooperatives.

Finally, how serious is the contribution of fish culture to the eutrophication of the lake. Lasco, et al (2005) in the UN-sponsored Millennium Ecosystems Assessment exercise on Laguna de Bay estimated that 13,800 tons of nitrogen are dumped into the lake each year, of which 79 percent come from domestic sources, 16.5 percent from agriculture activities and 4.5 percent from industrial effluent. However, Santiago et al from the SEAFDEC Binangonan Freshwater Station estimated that the nitrogen contribution from aquaculture is only in the order of 38.6 tons nitrogen per year. Thus, fish pens/cages may in fact be really very minor contributors to the eutrophication of the lake and is a trade-off we can live with. This methodology needs further validation.


Dr. Emil Q. Javier is a Member of the National Academy of Science and Technology (NAST) and also Chair of the Coalition for Agriculture Modernization in the Philippines (CAMP). For any feedback, email eqjavier@yahoo.com.

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  • DanteCatalino Garcia

    What to do? Dismantle once and for all!