The seven lakes are: Sampaloc, Palacpaquen, Mohicap, Calibato, Bunot, Pandin, and Yambo. Just like any other body of water, the lakeshore area harbors human settlement. The lakes are sources of water for domestic consumption such as bathing or cooking, with a nearby spring as source of drinking water. The lakes are a source of food, a variety of fish, shrimps, and mollusks such as Corbicula, commonly called tulya. Parts of the lakes are navigable. The lakes traditionally have been a common resource for everyone, without any restrictions on their use; any member of the community can fish in them. But what are the consequences for a resource common to everyone if used without restrictions and corresponding responsibilities?

In the mid-1970s, aquaculture of Tilapia nilotica was introduced in the country as an alternative source of cheap protein to answer the needs of our growing population. The tilapia grew successfully in fish pens in Laguna Lake, and eventually, fish cages were set up in nearby Sampaloc Lake. Setting up fish cages, seeding them with tilapia fry, and feeding the fish up to the adult stage require a significant investment, affordable only by middle-class members of the community or outside investors. This permit system virtually converted 10-12% of the lake for private use.

The introduction of aquaculture to the lakes deprived the poorer members of the lakeshore community of access to the totality of the common resource for open fishing and navigation. With the increase in population over the years, deterioration of the seven lakes commenced because of aquaculture practices, effluents from households, nutrient run-off and siltation from agriculture, and effluents from small-scale industries. The sustainability of the lakes was threatened. Would the lakes, through ecological succession, just be converted into a wetland dominated by water hyacinths and the edible kangkong?

Aquaculture in Philippine lakes was introduced by BFAR in the mid-1970s during the Marcos regime. With the projected growth of the country’s population and the consequent demand for food, Tilapia nilotica was brought in. The cage culture of tilapia was initially tested in Laguna Lake using fish pen structures. Tilapia easily acclimated to the tropical waters of Laguna Lake with high returns on investments so this simple technology was introduced to the lakeshore community of San Pablo City.

Tilapia aquaculture using fish cages was introduced to Sampaloc Lake in 1976. The industry expanded from 6 hectares to 28 hectares in 1989. Total production is now 4,383 metric tons or an average of 60 metric tons/hectare per year. With the success of this aquaculture practice, the technology was also introduced to the other lakes of San Pablo.