1st of 2 parts
KITCHARAO, Agusan del Norte (MindaNews / 6 December) — Along the stretch of the Pan-Philippine Highway connecting Butuan City and Surigao City, motorists catch sight of Lake Mainit, its deep blue waters stretching beside the road like a piece of the sea.
At small roadside stalls, vendors wave pieces of paper over piles of dried pijanga (Glossogobius giuris), the lake’s well-known native goby fish, inviting motorists to stop and “buy a piece of the lake.”
For the families living around Lake Mainit, the lake is more than a passing view; it is deeply intertwined with their lives.
Among those who know its waters best is Danny Merida, born and raised on its shores in Barangay San Roque, Kitcharao, Agusan del Norte. Now 53, he still fishes in the lake, keeping alive a tradition that has sustained his family and many others for decades.
But worry is growing among the community and stakeholders. A recently released stock assessment has revealed a troubling decline in pijanga, urging action to prevent a vital part of Lake Mainit from slipping away.
Stock assessment
Lake Mainit, the fourth largest lake in the Philippines, covers about 17,060 hectares, with a shoreline of 62.1 kilometers. At 219.35 meters deep, it is the country’s deepest lake. The lake is shared almost equally between the provinces of Agusan del Norte and Surigao del Norte, with 31 lakeshore barangays in the municipalities of Mainit, Alegria, Kitcharao, and Jabonga.
In July 2025, stakeholders from municipalities surrounding Lake Mainit gathered in Jabonga, Agusan del Norte, as the Department of Agriculture–Bureau of Fisheries and Aquatic Resources (DA-BFAR) Caraga presented key findings from the stock assessment of pijanga, conducted under the ongoing National Stock Assessment Program.
Joyce Baclayo, senior aquaculturist of DA-BFAR Caraga, confirmed that pijanga catches have been steadily declining from 2014 to 2024. In an exclusive interview with MindaNews, she said the trend raises growing concerns about the stock’s sustainability.
According to data shared with MindaNews, the decline was measured using landed catch figures. From 2014 to 2024, pijanga remained the dominant species in the lake, accounting for 78% of the total annual fish catch in Lake Mainit—one reason the stock assessment focused on it.
Baclayo said that the figures came from monitoring conducted almost every month for 20 to 21 days, with two-day breaks in between, making the data robust and reliable.
The assessment showed that the pijanga fishery has exhibited a sustained downward trend over time, with a particularly notable drop in the last four years, from 2020 to 2024.
“This pattern highlights growing concerns about the stock’s sustainability and the need for effective management measures,” she said.
Catches peaked at 373 metric tons in 2016 and 2019. In 2020, the landed catch dropped significantly to 252 metric tons. From 2022 to 2024, catches ranged between 235 and 260 metric tons, showing only slight fluctuations.
Baclayo pointed out that comparing the peak in 2016 (373 metric tons) to 2024 (260 metric tons) indicates a 30.3-percent decline. She added that there are currently no signs of recovery.
Performance indicators
On top of analyzing landed catch trends, Baclayo said the team also assessed the biological condition of pijanga.
“When we talk about biological condition, we consider measurements like length at first maturity and catch per unit effort. These are the biological indicators of the stock,” she said.
These measurements, Baclayo explained, form the foundation for evaluating the health of the stock—whether the population remains abundant or is in decline.
For the analysis, models and analytical tools were applied alongside the catch trend, confirming the sustained downward pattern.
The first biological indicator examined was the percent mature, which measures the proportion of fish in the catch that have reached their first reproductive maturity. Baclayo said there is a clear problem with this indicator.
“Ideally, fish should be caught at or above their first maturity size—for example, pijanga at 14 cm. However, many of the fish caught are smaller, from 6 cm to 9 cm. When calculated as a proportion, immature fish dominate the catch,” she said.
Baclayo explained the reference points used to interpret the percent mature in the catch. The target reference point for sustainability is 90-100% of the total catch being mature fish.
“This is the ideal range, meaning most of the catch has reached reproductive maturity and the stock is being harvested sustainably,” she said.
The second reference point, called the trigger reference point, is 51–89% mature fish, which is considered a warning zone, indicating that the percent mature has fallen below the target but is not yet critical.
The last reference point, the limit reference point, is when less than half of the catch is mature. This signals overfishing and insufficient reproduction.
Baclayo said that the current stock of pijanga is already below the 50% threshold, with percent mature values ranging from 18% to 34% between 2015 and 2022.
“This proportion of immature fish is a key indicator that recruitment is affected. There are not enough mature fish to reproduce, and replacement of the population is problematic,” Baclayo said.
Fishing pressure
Merida, president of the Kitcharao Maharlikan Fishermen Cooperative (which was founded in June 2023 and currently with 43 members), said he has noticed a decline in pijanga catches.
Using laya, a legal traditional fishing method in Lake Mainit that is a modified boat cast net, he now harvests about 20 kilograms of pijanga per trip, a roughly 50% decrease from what he could catch in the early 2000s.
By comparison, a 2008 assessment conducted under the Sustainable Fisheries Management Program for Lake Mainit, a study funded by the Department of Science and Technology aimed at establishing a comprehensive fisheries management program to sustain the lake’s resources, found that the peak mean catch per fisherfolk per trip using laya was 90 kilograms. Merida attributed the decline partly to the growing number of fishermen now operating in the lake.
While no recent comprehensive data exists for all fishers operating across Lake Mainit, data from the Sustainable Fisheries Management Program for Lake Mainit across six municipalities — Mainit, Alegria, Kitcharao, and Jabonga as well as along the Kalinawan River in Santiago and Tubay — showed that some 1,754 fishers and 1,546 fishing boats were involved in Lake Mainit fisheries in 2008.
In addition to declining landed catches and maturity percentage, the biological condition of pijanga is reflected in its catch per unit effort (CPUE), which measures how much fish is caught per unit of fishing effort, in this case, per fishing boat. BFAR Caraga data from 2018 to 2022 show a clear downward trend.
“In 2018, one boat could catch 43 kilograms of pijanga. Now, the same effort yields only 28 kilograms,” Baclayo said.
Dr. Asuncion B. de Guzman, a marine biologist at Mindanao State University Naawan Foundation for Science and Technology Development and project leader of the Sustainable Fisheries Management Program for Lake Mainit from 2007 to 2009, told MindaNews in an interview that fishing pressure in Lake Mainit is high.
“The fishing effort is high. There are so many fishers and so many different fishing gears being used. For a relatively small lake like Mainit, the diversity of gear is extreme,” she said.
In their study, De Guzman noted that they were able to list 36 different types of fishing gear, many of them modified versions of common nets, some of which are highly unsustainable.
She added that the combination of too many fishers and highly diversified gear is a major factor driving overfishing in the lake.
“Fishing in such a small water body with so many fishers and so many gear, what do you expect?” De Guzman said. (Ivy Marie Mangadlao / MindaNews)
Next: Catching the saguyon threatens the pijanga
This story is published with the support of Canal France International under the Media for One Health program.
