Lawrence Christian Verzosa

Home of ecosystem services, San Pablo’s seven lakes served as the lifeline of local communities and tourism in Laguna—bringing forth the beauty that was accidentally created by phreatomagmatic eruptions.

Photo Courtesy of San Pablo City Association.

Lakes Bunot, Calibato, Palakpakin, and Sampalok are used for fishery mainly for milkfish or tilapia, while Lakes Mojicap, Pandin, and Yambo are sites for ecotourism.

As vital sources of income, these lakes eventually gave rise to human activities, demanding for up-scaled production and technology such as construction of fish pens.

Consequently, these gifts of nature are in danger as their water quality deteriorates, according to the recent water assessment of the University of the Philippines (UP) Los Baños and the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development of the Department of Science and Technology (DOST-PCAARRD).

In a Saribuhay episode, UP Los Baños Assistant Professor John Vincent Pleto said that the ongoing anthropogenic and ecological processes led to problems with pollution and overcrowding of fish pens which are the primary prospects for the said degradation. 

“Dahil din sa pagbabago sa kalidad ng tubig at presensya ng invasive species, nagkakaroon ng fish kill o pagkamatay ng maraming isda na nakakaapekto sa kabuhayan ng komunidad na umaasa sa mga lawa,” Pleto said.

Pleto, in coordination with DOST-PCAARRD, started the project “Development of Models for the Assessment and Monitoring of the Seven Lakes of San Pablo,” which includes the water quality index and the Bayesian network model.

The water quality index is an aggregated water parameter that measures the lake’s physical, chemical, and biological properties to describe its overall quality.

On the other hand, the Bayesian network model uses the correlation between water quality, climate, and aquaculture practices to forecast the occurrence of fish kill.

In their recent scorecard, only the water quality of Lakes Yambo and Pandin were classified as ‘excellent’ which indicates outstanding condition that is suitable for aquatic life, while the rest falls to ‘good’ that shows satisfactory levels of water due to moderate presence of pollutants.

Pleto highlighted the importance of monitoring water quality as it provides evidence in making sound decisions for the lake ecosystem.

”To conserve and protect our lakes and its biodiversity is to maintain ecological balance and ensure the future generation of the beauty and resources we have now,” he said.

Along these models, they are looking forward to conducting a stakeholders forum to discuss recommendations and policies for the lakes’ welfare.