In Pangasinan, ‘bangus’ growers brace for fish kills amid extreme heat

POND WORK Fishpond workers in Binmaley, Pangasinan, segregate smaller "bangus" caught in their net as the bigger milkfish will be transferred to separate ponds where these will be further cultured. —WILLIE LOMIBAO

DAGUPAN CITY—“Bangus” (milkfish) industry players in Pangasinan are urging fish farmers to prepare for “gataw,” a phenomenon where cultured fish swim to the surface and gasp for air due to high temperatures and low oxygen levels in the water as parts of Luzon suffer from extreme heat.

Christopher Sibayan, president of the Samahang Magbabangus sa Pangasinan, warned that extreme heat, combined with overcrowded fishponds, could deplete dissolved oxygen levels, potentially leading to fish kills.

Westly Rosario, former Bureau of Fisheries and Aquatic Resources Dagupan research center chief, said ponds with low water levels are more vulnerable to heat stress.

“Fish are naturally smart. If the upper layer of water is too warm, they will swim deeper where it’s cooler. That’s why pond operators must maintain at least a 1-meter water level,” he said.

Rosario added that fish grown in sea cages are less affected by heat stress since they can retreat to deeper, cooler waters.

Proactive measures

Sibayan noted that while “gataw” cases remain minimal in some towns, the rising temperature calls for proactive measures.

As of Thursday, the heat index in Dagupan City peaked at 45 degrees Celsius, which is considered within the “danger level,” according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration.

Sibayan warned that sudden rain could drastically change pond water temperatures, increasing the risk of fish kills.

To mitigate losses, he advised pond operators with overstocked ponds to harvest some fish early, even if they are below the marketable size of 350 grams.

“You may lose some fish now, but it’s better than suffering a full-blown fish kill,” he cautioned.

Rosario echoed this advice, recommending selective or partial harvesting to manage stock density and maintain water quality.

SPECIAL SKILL It takes a keen eye, speed and experience to become a “bangus” classifier, known as “managsaysay,” as newly harvested milkfish are unloaded daily at Magsaysay fish market in Dagupan City. —WILLIE LOMIBAO

Call for vigilance

In Sual town, Alex Soriano, president of Tiera Norte, a major player in the country’s bangus industry, reported no cases of fish kills in the province’s production areas.

However, he warned that operators must remain vigilant, especially during April and May when the rainy season begins.

Rosario explained that heavy nutrient accumulation from uneaten fish feed and pollutants could lead to algal blooms in production areas.

A sudden change in temperature and salinity due to rain could cause these planktons to die off, leading to a sharp drop in dissolved oxygen and suffocating the fish.

To counter this, Sibayan recommended investing in water pumps and aerators to improve oxygen circulation in ponds. He noted that low dissolved oxygen levels, which trigger “gataw,” typically occur at dawn.

“That’s why we start aerating our ponds around midnight,” he said.

Farmgate prices

The farmgate prices of bangus are currently pegged at P140 to P150 per kilo in Pangasinan.

For several months last year, prices plummeted to P90 to P100 per kilo, way below production cost of P125 to P135 per kilo.

According to the Philippine Statistics Authority, Pangasinan remains the top bangus-producing province in the Ilocos region, contributing nearly 90 percent of the region’s total output in 2023. The province produced 170,870 metric tons of bangus that year.

Major bangus production areas in Pangasinan include mariculture parks in Anda, Bolinao, Sual and Infanta towns for sea cages, while fishpond production is concentrated in Dagupan City and Lingayen, Bugallon and Binmaley towns.