Sampaloc Lake

Solid and liquid waste. One notable observation for Sampaloc Lake is the long-standing problem with the improper disposal of solid and liquid wastes by informal settlements, tourists, households, and private establishments. According to the participants of the Sampaloc Lake FGD, informal settlements that used to encroach Sampaloc Lake since before the 1980 until 2017 had no garbage bins and sewerage systems, and discharged garbage and wastewater directly into the lake. In addition, tourists disposing garbage improperly since before 1980 increased in number due to the development of Sampaloc Lake for ecotourism. Further, the lack of  solid waste management at the barangay level, which can be traced to households not segregating their wastes, contributes to the solid waste problem in the barangays surrounding the seven lakes until 2022. The waste management facility with a sanitary landfill managed by the local government unit (LGU) of San Pablo is located in barangay Sto. Niño Baloc San Pablo. As of 2022, 43 out of 80 barangays in San Pablo have their own dump trucks, however, the dump trucks of the barangays are not used regularly and the wastes collected are not segregated. Moreover, the black and gray wastewater coming from households and private establishments with no proper sewerage system further contribute to the pollution of the lake.

Increased surface runoff due to anthropogenic activities. Another long-term stressor for Sampaloc Lake is the increase in surface runoff due to anthropogenic activities in the surrounding barangays. This usually happens when it rains, and sources of contaminants such as dirt, fertilizer, and chemicals include houses, businesses, vehicles, and farms. 

Proliferation of fish cages. Starting the 1990s until 2017, the number of fish cages increased to more than the 10% carrying capacity of the lake. This equated to lake water eutrophication, mainly due to the overcrowding of fish cages and overfeeding. Eutrophication, in turn, caused algae growth and a number of fishkills (Natuel, 2023?). This was resolved by gradually removing the unregistered fish cages and establishing a fish cage belt zone, where the 10% aquaculture carrying capacity of Sampaloc was transferred in 2018.

Introduced / invasive species. Lastly, locals estimated that introduced species, such as red devil fish and jaguar fish, entered the lake between 1991 and 1995. The residents who reside near the lake said that these species of fish are being dumped in the lake by hobbyists when they no longer want to keep them. However, since there is no evidence to validate this claim, BFAR cannot interfere with hobbyists who choose to raise ornamental fishes, among other species, since this is legal and not considered high risk.

Another potential source is fishermen who outsource their fingerlings, which might include eggs of introduced or invasive species. Although the government cannot constantly monitor the lake, BFAR has programs to prevent the entry of introduced or invasive species into the seven lakes.