Erratic weather harmful to Pangasinan ‘bangus’
BINMALEY, PANGASINAN—At 2 a.m. of May 16, Joebert Correa, 57, waded into his fishpond here after noticing the “bangus” (milkfish) he was raising were gasping for air following a light rain.
“I already turned on the aerator at 12 a.m., but I observed that the fish were not swimming toward the area where the water was moving. So I got a water pitcher and poured water on them so they would swim toward the aerator. Otherwise, they would have died due to lack of dissolved oxygen,” Correa told the Inquirer.
He was fortunate to save his milkfish stock. But elsewhere in the town, a fish pen operator suffered big losses after being forced to harvest his bangus stock when the fish began gasping for air following the rains in recent days.
The rains have already resulted in “gataw” in some fishery areas in Pangasinan. Gataw happens when cultured fish swim to the surface and gasp for air due to high temperatures and low oxygen levels in the water.
Joey de Leon, a fishpond owner and fishery technician, said the towns of Binmaley, Lingayen and Bugallon have been affected by massive gataw, forcing operators to harvest their stocks early.
In Binmaley, at least four barangays have already been affected by gataw, while one barangay in Dagupan City has also experienced the phenomenon following the recent rains.
Challenge
Rain after prolonged hot weather poses a challenge to aquaculture operators because it disrupts thermal stratification, causing warm, oxygen-poor water from below to rise while cooler, oxygen-rich water from the surface sinks.
“The upturn of water could result in low or even depleted oxygen in the upper water column, and the fish gasp for air. Without aeration, the situation could result in fish kill. Gataw is expected during the onset of the rainy season,” said Ronald Eugenio, a fish cage operator in Sual town.
Aerators, such as paddle wheels, are commonly used in aquaculture areas to generate current that circulate oxygenated water throughout ponds.
Bangus growers fear the worst especially with the onset of a strong El Niño, expected from June to August.
“Most of us, especially fishpond owners, are ready with aerator machines like paddle wheels. Those whose stocks are ready for the market harvest the fish. Those with stocks that are still not marketable are sometimes also harvested but sold at very low prices,” he said.
De Leon said fish affected by gataw remain safe for consumption, but are usually sold for only P90 to P120 per kilo after forced harvest, below the production cost of P130 to P150 per kilo.
