Lake Bato, the seventh largest lake in the Philippines, spans 2,810 hectares across the provinces of Camarines Sur and Albay. Averaging eight meters in depth, it is a vital inland water body co-managed by the municipalities of Bato and Libon. Despite its ecological and economic significance, Lake Bato has remained relatively understudied, especially in terms of capture fisheries. Much of the existing research has focused on water quality and aquaculture, leaving a gap in understanding its wild fish stocks and the communities that depend on them.

This is beginning to change.

Under the National Stock Assessment Program (NSAP), spearheaded by the DA-NFRDI and the DA-Bureau of Fisheries and Aquatic Resources (BFAR), Lake Bato is now one of two inland lakes, along with Lake Naujan, selected for focused monitoring from 2025 to 2026. With four field enumerators stationed at eight landing sites, the lake is finally receiving the attention it deserves, not only as a productive fishing ground, but also as a possible habitat for species found nowhere else in the world. At the center of this renewed interest is a fish known locally as tabyos. Small, transparent, and often easily overlooked, tabyos have long been an integral

part of the local diet and economy. It is often confused with the sinarapan (Mistichthys luzonensis), the world’s smallest commercially harvested fish, found in nearby Lake Buhi. However, recent findings suggest that tabyos may be something else entirely, a distinct, possibly endemic goby species native only to Lake Bato.

Clarifying species identity

A major source of confusion in the taxonomy of tabyos stems from the inconsistent use of local names. In many areas, tabyos refers to sardine fry, while in the Bicol region, it can also refer to various small goby species. The term sinarapan, on the other hand, is more specific, historically used for the smallest fish endemic to Lake Buhi, caught using a gear called sarap.

Through a combination of morphological assessment and preliminary genetic work, NFRDI researchers are now identifying tabyos as likely Gobiopterus luzonensis batonensis (Aurich), a species noted in historical literature published in proceedings of the Biological Society of Washington published in 1944, but has never been fully described. This is not just a technical clarification, but potentially a major discovery.

If confirmed, this would mean tabyos is a distinct, possibly endemic species, with Lake Bato as its only habitat.

The lake’s fisheries, by the numbers

Lake Bato is a working lake. According to the recent inventory data, 1,266 fisherfolk operate on the lake, using 1,245 boats and nearly 49,000 units of fishing gear. Sixteen different gear types are in use; some specialized for catching tabyos during its seasonal peak.

During peak catch months, a single fisher can haul up to 50 kilograms of tabyos a day. It is sold fresh, dried, or fermented, and while prices vary, its value is comparable to that of sinarapan. In fact, tabyos have increasingly replaced sinarapan in markets, especially since the latter’s stocks in Lake Buhi started to crash due to overfishing and habitat degradation.

The economic pressure makes the distinction between the two species more than a scientific footnote. If tabyos is indeed unique to Lake Bato, then it’s not just a local delicacy, it is an endemic resource that needs careful management.

NFRDI’s efforts to protect stocks

To get ahead of the curve and prevent the same kind of stock collapse experienced by sinarapan, researchers are now studying tabyos’ reproductive cycle. Knowing when it breeds, how many eggs it produces, and at what size it matures can help fisherfolk decide when (or if) fishing restrictions are needed.

If successful, these efforts could offer a sustainable alternative to wild harvesting, supporting the 1,266 fishers who depend on the lake, while preserving one of its most distinctive native species. Captive rearing could also serve as a conservation tool, ensuring that tabyos populations remain viable even if wild stocks decline.

Rising threats

Not all pressures on Lake Bato come from overfishing. Another emerging issue is the rise of non-native species, introduced accidentally or through fish cage operations.

The lake has seen an increase in fish pens and cages, often stocked with other exotic species. When these escape, or are released without oversight, they can alter the food web and compete with native fish like tabyos for habitat and resources.

Early catch data already indicated a growing proportion of introduced species in the lake’s total catch. While aquaculture has become a lifeline for many rural communities, the lack of regulation around species introductions poses long-term risks to biodiversity. DA-NFRDI researchers hope the data can help inform more responsible aquaculture practices, including species control and habitat protection in the region.

Building a foundation for inland fisheries management

The work at Lake Bato is still in its early stages. But the information gathered through the NSAP will serve as a baseline for future resource management. Species identification, gear inventories, and reproductive studies all contribute to a more accurate understanding of the lake’s fisheries.

The hope is that this science-based approach will not only prevent overexploitation but also ensure that tabyos, a species that may exist nowhere else, is not lost to mismanagement or neglect. For the communities around Lake Bato, securing a resource that has long been central to their livelihood is crucial. For fisheries managers and researchers, it is a step toward filling a long-standing data gap in inland fisheries. ### (Ann Dominique del Valle and Jeremiah Barela)