Inland fisheries, found in rivers, lakes, and reservoirs, are vital sources of food, livelihood, and identity for millions of Filipinos. Though often overlooked compared to marine fisheries, inland fisheries play a crucial role in supporting rural economies, feeding inland communities, and conserving unique aquatic biodiversity.

According to the Philippine Fisheries Profile published by the DA-Bureau of Fisheries and Aquatic Resources (BFAR), inland fisheries in the Philippines, mostly small-scale operations in lakes, rivers, and wetlands, produced an estimated 174,500 metric tons (MT) in 2023, supporting thousands of fisherfolk and aquaculture workers.

These fragile ecosystems, often closed or semi-closed, are highly vulnerable and struggle to recover once overexploited. With mounting threats such as overfishing, pollution, invasive species, and unregulated aquaculture, the sustainable management of inland fisheries depends on one critical foundation: science.

From science to policy

The DA-NFRDI, as the research arm of the DA-BFAR, has worked for years to support inland fisheries management through science. One of its key tools is stock assessment, which involves collecting and analyzing data on fish catch, fishing effort, fish size, species abundance, and spawning patterns. These studies provide a solid scientific foundation for managing inland fisheries, aiming to protect fish stocks while sustaining the livelihoods of communities that rely on them.

The Institute’s inland fisheries research largely began in Lake Taal. From 1996 to 2024, the lake served as a hub for scientific studies. Researchers monitored the population of Sardinella tawilis, the world’s only freshwater sardine, studied introduced species, documented the reproductive cycles of native fish, and tracked changes in fishing practices over time.

The findings from these studies informed key policy decisions, including seasonal fishing bans during spawning periods, restrictions on destructive fishing gear, and establishment of no-take zones. The Protected Area Management Board (PAMB), which oversees the lake, used this science-based evidence to guide its management strategies. In this way, research became a bridge to action, benefiting both ecosystems and communities.

Since these management decisions were grounded in scientific evidence, they earned credibility not only among government agencies but also among local government units (LGUs) and communities. Science helps foster consensus, making policies more effective and defensible.

Strengthening research partnerships

DA-NFRDI’s inland stock assessment efforts are steadily expanding. In 2023, the program extended beyond Lake Taal to include Lake Buhi, home to sinarapan (Mistichthys luzonensis), the world’s smallest commercial fish. While not yet endangered, sinarapan is considered vulnerable to threats including overfishing and predation.

In 2025, two more lakes (Bato and Naujan) were added to the program, each with distinct ecological and fisheries profiles. And with the recent partnership between NFRDI and the Laguna Lake Development Authority (LLDA), research initiatives are now being extended to Laguna de Bay, the country’s largest freshwater lake. Across all sites, DA-NFRDI applies a consistent approach: collecting data on catch, effort, gear use, and biological indicators to better understand and manage inland fish stocks.

Simultaneously, the National Stock Assessment Program (NSAP), implemented by DA-BFAR regional offices with technical guidance from DA-NFRDI, has expanded monitoring efforts to rivers in the Cordillera Administrative Region (CAR) and Lake Mainit in Caraga region, further broadening the scope of inland fisheries research nationwide.

Despite the ecological differences among these water bodies, the core research questions remain the same: What is the condition of fish stocks? How much is being caught? What types of gear are used, and how is fishing effort distributed over time and space?

Armed with these insights, policymakers are better equipped to make informed, science-based decisions on conservation, regulation, and sustainable development.

Going beyond stock assessment

DA-NFRDI’s inland fisheries research goes beyond monitoring fish stocks. In 2022, the Institute led a one-year ecological risk assessment of introduced species across five major lakes, including Laguna de Bay, Naujan, Buhi, Mainit, and Paoay.

Using the Aquatic Species Invasiveness Screening Kit (AS-ISK), the study identified potentially invasive non-native species, such as janitor fish and certain tilapia strains, which pose threats to native biodiversity and local fisheries.

That same year, DA-NFRDI conducted a study on the aquaculture carrying capacity of Lake Taal. The research estimated the lake’s ecological limits for fish cage production, supporting the development of local policies to regulate the number and location of cages, ensuring a balance between aquaculture expansion and environmental sustainability.

Equally significant were ichthyoplankton assessments or studies focused on fish eggs and larvae to identify key nursery and spawning areas. In Lake Taal, a four-year assessment provided the scientific basis for establishing Tawilis Reserve Areas in four municipalities, now formally recognized through a PAMB resolution. A similar one-year study in Lake Buhi was also completed and presented to the PAMB, offering early guidance for protecting native species habitats.

These research outputs are more than technical reports; they are decision-making tools. Across project sites, NFRDI has strengthened the capacity of LGUs, Protected Area Management Offices (PAMOs), state universities and colleges (SUCs), and fisherfolk communities through training, field collaboration, and open access to scientific findings. These initiatives have also generated employment opportunities for local fisheries graduates, many of whom are now trained and employed as technical data enumerators, transforming science into a platform for both skills development and livelihood.

As climate change, development pressures, and resource competition continue to grow, inland fisheries face increasing challenges. Through applied science and strong local partnerships, DA-NFRDI works to protect the health of freshwater ecosystems while sustaining their productivity for future generations.

With science as its compass and collaboration as its strength, DA-NFRDI remains committed to securing the future of inland waters, where life, livelihood, and learning converge. ### (Ma. Lourdes Merilles)