In today’s modern world, the role of science extends beyond the confines of the laboratory. Translating research results into management policy underscores the importance of using scientific knowledge in decision-making. It ensures that policies are science-based, leading to more effective, efficient, and sustainable outcomes.

The National Fisheries Research and Development Institute (NFRDI), an attached agency of the Department of Agriculture (DA) and the primary research arm of the Bureau of Fisheries and Aquatic Resources (BFAR), has been conducting relevant research and development (R&D) initiatives to provide the scientific foundation for government policies and strategies that contribute to food security efforts in the country.

The study on Sardinella tawilis was NFRDI’s key research initiative, leading to the development of management strategies and policies on fishery management and conservation.

The R&D Program on Tawilis Conservation, initiated and established by the Freshwater Fisheries Research and Development Center (FFRDC) in Taal, Batangas, specifically focused on determining the spawning season and spawning grounds of tawilis. The scientific information generated from this study served as the basis for recommending the conservation and management of the tawilis population in Taal Lake.

Economic importance of tawilis

Tawilis, or Bonbon sardine, is the only freshwater sardine endemic to Taal Lake, the third-largest lake in the Philippines. This fish species primarily feeds on plankton, making it a planktivore.

Originally, tawilis and other sardine species were marine fish. However, after the eruption of Taal Volcano in 1754, Taal Lake was separated from Balayan Bay, and the marine tawilis population eventually adapted to the freshwater environment of Taal Lake.

Tawilis is the most important commercial fishery in Taal Lake, leading to the lake’s designation as a protected landscape in 1996 through Proclamation No. 923.

Among the major sardine species in the Philippines, the closest to tawilis are Sardinella albella (Balayan Bay) and Sardinella hualiensis (Cagayan Province).

Tawilis is a culinary delicacy highly valued among Filipinos. It is processed into various food products and can be eaten dried, salted, or smoked. There are countless ways to prepare tawilis, but the most popular dish is fried and crispy tawilis, often served with vinegar or accompanied by unripe mangoes, tomatoes, and onions.

NFRDI’s R&D initiatives on tawilis

In a series of studies conducted by FFRDC led by Dr. Maria Theresa Mutia, Scientist I and Chief Science Research Specialist, it was found that tawilis production declined by more than 50 percent from 1996 to 2018.

Consequently, in 2018, the International Union for Conservation of Nature (IUCN), the global authority assessing the conservation status of species, declared tawilis as “endangered.” This classification indicates that the species faces a very high risk of extinction in the wild, necessitating urgent conservation actions.

The NFRDI study revealed that tawilis has a high exploitation value of 0.53-0.65, indicating overfishing at unsustainable levels. Factors contributing to the decline include overfishing, habitat degradation, pollution, and the introduction of invasive species, all of which have significantly impacted the tawilis population in Taal Lake.

To generate scientific information for the conservation and management of the tawilis population in Taal Lake, FFRDC launched the R&D Program on Tawilis Conservation. This program focused on determining the spawning season and spawning grounds of tawilis.

The results indicated that the spawning season occurs from March to April, with the gonadosomatic index (GSI) and the percentage of gravid tawilis peaking during this period. The spawning grounds were identified in the lake vicinities of Balete, Mataasnakahoy, Cuenca, and San Nicolas in Batangas. Additionally, the study determined that the appropriate gillnet mesh size for tawilis, corresponding to the length at 50 percent maturity, was 3.05 cm (11k).

Scientific findings from Dr. Mutia’s group were published in various scientific journals, including the Philippine Journal of Science and The Philippine Journal of Fisheries. These scientific data have also served as the basis for issuing various fishery regulations and proclamations within Taal Lake.

Closed season and other conservation efforts

With the publication of NFRDI studies on tawilis, particularly on its spawning season and spawning grounds, conservation efforts have been undertaken to protect and replenish the stocks to sustainable levels.

NFRDI conducted a series of presentations of its research findings to stakeholders, leading to the issuance of TVPL-PAMB Resolution No. 49, Series 2018: Closed Fishing Season of Tawilis. This resolution cited the NFRDI study on the spawning patterns and larval distribution of tawilis.

The resolution was further expanded with the issuance of TVPL-PAMB Resolution No. 63, Series 2019: Expansion of Resolution No. 49 Closed Fishing Season of Tawilis, and TVPL-PAMB Resolution No. 64, Series 2019: Establishment of 4 Tawilis Reserved Areas/Tawilis Sanctuaries.

The NFRDI studies have also become the basis for the Unified Rules and Regulations for Fisheries (URRF) specific to tawilis, designed to manage and conserve the species in Taal Lake. These include implementing a closed season, regulating mesh size, and establishing Tawilis Reserve Areas (TRA).

Implementing a closed season from March to April, the breeding period of tawilis, allows the population to reproduce and grow without fishing pressure. Fishing gear restrictions prohibit the use of specific types of fishing gear harmful to tawilis and other aquatic life. It includes banning fine mesh nets that catch juvenile tawilis and other non-target species.

Fishers are also required to adhere to minimum size limits for catching tawilis, ensuring that only mature individuals are harvested, and younger fish have the opportunity to grow and reproduce. Most importantly, certain areas of Taal Lake are designated as protected zones where fishing is restricted or entirely prohibited, creating safe havens for tawilis to thrive.

These regulations are part of a comprehensive approach to ensure the long-term conservation and sustainability of the tawilis population in Taal Lake.

Since 2022, NFRDI has been collaborating with the Department of Environment and Natural Resources-Taal Volcano Protected Landscape-Protected Area Management Office (DENR-TVPL-PAMO) to strengthen the enforcement of the tawilis closed fishing season. As part of these efforts, a motorcade is held every February around the coastal municipalities of Lake Taal to raise public awareness.

Now in its fifth year, the closed fishing season is continuously being implemented in the country. “Through our research at NFRDI, the spawning season and grounds of tawilis were confirmed, providing scientific data for the formulation of conservation policies for tawilis,” Dr. Mutia said.

She also reported a high compliance rate and strong support from local government units. “A harmonious relationship among government agencies, non-government organizations, and fisherfolk organizations is imperative in securing the livelihood of small-scale fishers while conserving the lake’s fishery resources,” Dr. Mutia underscored.

Ways forward

NFRDI continues to collaborate with relevant agencies and stakeholders to safeguard the sustainability level of tawilis in Lake Taal.

Among these initiatives include continuous Information, Education, and Communication (IEC) campaign, strict implementation of the closed fishing season and Tawilis Reserve Areas (TRAs), livelihood assistance for tawilis fisherfolk affected by the closed fishing season, and development of the Tawilis Conservation Roadmap.

NFRDI has also been involved in several collaborative projects on tawilis breeding with the Bureau of Fisheries and Aquatic Resources – National Inland Fisheries Technology Center (BFAR-NIFTC) and BFAR Region 4A, as well as in ongoing research and development on the stock assessment of Lake Taal fisheries.

Results of the stock assessment of Lake Taal from 2014 to 2016 showed that the average catch of tawilis was about 11 kilograms per day. However, from 2017 to 2018, the average catch of tawilis dropped to only 6 kilograms per day. Conservation efforts began in 2019 with the issuance of various TVPL-PAMB Resolutions to implement a closed fishing season. From 2021 to 2023, an NFRDI stock assessment study in Lake Taal showed that the average catch of tawilis has increased to more than 10 kilograms per day. “This data proves that the implementation of the closed season on tawilis is having a positive impact on the sustainability of tawilis,” Dr. Mutia concluded. (Rita dela Cruz)