As scorching heat grips parts of Luzon, bangus (milkfish) farmers in Pangasinan, the Philippines’ top milkfish-producing province, are sounding the alarm over a phenomenon known as “gataw.” This occurs when cultured fish, struggling with high temperatures and depleted oxygen levels in pond water, swim to the surface and gasp for air. With the heat index in Dagupan City recently peaking at a dangerous 45 degrees Celsius, industry leaders are urging farmers to take urgent measures to prevent devastating fish kills.

Christopher Sibayan, president of the Samahang Magbabangus sa Pangasinan, has warned that overcrowded fishponds, combined with extreme heat, could drastically reduce dissolved oxygen levels, creating a lethal environment for bangus. “We’re seeing minimal cases of gataw in some towns now, but with temperatures rising, we can’t afford to be complacent,” he said. The stakes are high in Pangasinan, which contributes nearly 90% of the Ilocos region’s bangus output, producing over 170,000 metric tons in 2023, according to the Philippine Statistics Authority.

A Race Against Nature

The current heatwave, exacerbated by broader climate trends, poses a severe threat to fishponds with low water levels, where fish are more vulnerable to heat stress. Westly Rosario, former chief of the Bureau of Fisheries and Aquatic Resources Dagupan research centre, explained that maintaining adequate water depth is critical. “Fish are naturally smart. If the upper layer of water is too warm, they’ll swim deeper where it’s cooler. Pond operators must ensure at least a 1-metre water level to give them that option,” he advised.

Unlike fish in sea cages, which can retreat to deeper, cooler waters, those in shallow ponds face greater risks. Rosario noted that sudden rain, often a relief in hot weather, can also be a danger. A rapid drop in pond water temperature or changes in salinity can trigger mass die-offs of plankton, further depleting oxygen and suffocating fish. Heavy nutrient accumulation from uneaten feed and pollutants also heightens the risk of algal blooms, which can collapse under changing conditions, creating a deadly domino effect.

To mitigate these threats, industry leaders are advocating proactive steps. Sibayan recommends that farmers with overstocked ponds harvest some fish early, even if they fall below the ideal 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 supports this approach, suggesting selective or partial harvesting to manage stock density and maintain water quality.

Economic Pressures and Market Volatility

The urgency to act is compounded by economic pressures facing bangus farmers. Current farmgate prices in Pangasinan range from P140 to P150 per kilo, a welcome recovery from last year’s lows of P90 to P100 per kilo, which fell below the production cost of P125 to P135 per kilo. However, the threat of fish kills looms large over an industry already battered by price volatility and rising operational costs. For many small-scale farmers, a single mass die-off could spell financial ruin.

Pangasinan’s bangus production is concentrated in key areas: mariculture parks with sea cages in towns like Anda, Bolinao, Sual, and Infanta, and fishponds in Dagupan City, Lingayen, Bugallon, and Binmaley. While sea cage operators face fewer risks from heat stress, fishpond farmers are on high alert, particularly as the rainy season approaches in April and May. Alex Soriano, president of Tiera Norte, a major player in the country’s bangus industry based in Sual, reported no fish kills in the province’s production areas so far. Nonetheless, he stressed the need for vigilance during the coming months.

Practical Solutions and Long-Term Challenges

To combat the immediate risks of gataw, which often peaks at dawn due to low overnight oxygen levels, farmers are being encouraged to invest in water pumps and aerators. Sibayan explained that many operators in Pangasinan begin aerating their ponds around midnight to boost oxygen circulation. While effective, these measures require capital investment, a challenge for smaller farmers already stretched thin by tight margins.

Beyond short-term fixes, the bangus industry in Pangasinan faces deeper, systemic challenges linked to climate change. Rising temperatures and unpredictable weather patterns are not isolated issues but part of a broader trend affecting aquaculture across South East Asia. The Philippine Atmospheric, Geophysical and Astronomical Services Administration has flagged the current heat index as within the “danger level,” a warning echoed by the Department of Health, which has cautioned against heat-related illnesses among the general population.

### A Call for Support and Adaptation

For now, Pangasinan’s bangus farmers are adapting as best they can, balancing immediate survival with the need for sustainable practices. Industry leaders are calling for greater government support, including subsidies for equipment like aerators and technical assistance to improve pond management. There is also a push for research into heat-resistant bangus strains or alternative farming methods that could withstand increasingly hostile environmental conditions.

As the heatwave persists, the resilience of Pangasinan’s bangus industry is being tested. While no major fish kills have been reported yet, the coming weeks will be critical. For farmers like those in Binmaley, meticulously segregating smaller bangus from larger milkfish to be transferred to separate ponds for further culturing, every day is a battle against nature’s unpredictability. Their efforts reflect not just a fight for livelihood but a broader struggle to adapt to a warming world—a challenge that extends far beyond the fishponds of Luzon.

With over 170,000 metric tons of bangus produced annually, Pangasinan remains a cornerstone of the Philippines’ aquaculture sector. Yet, as temperatures climb and weather patterns shift, the future of this vital industry hangs in a delicate balance. Farmers, industry leaders, and policymakers alike must act swiftly to ensure that the region’s “white gold” does not become a casualty of climate change.