Hundreds of “bangus” (milkfish) floated in ponds and cages in Barangay Salapingao here over the weekend, but many fish growers harvested their stocks before the fish kill, which was traced to a phenomenon called “neap tide” involving low oxygen levels in the water. Hundreds more bangus swam close to the water surface to take in oxygen and were quickly harvested, said city agriculturist Emma Molina. A neap tide happens twice a month when gravitational forces of sun and moon cancel each other out, generating the lowest rise and fall of the tidal levels. Because the tides are at their lowest ebb, the dissolved oxygen in the water are also at their lowest levels.

Cardinoza, G. (2015, September 24). Death of Dagupan 'bangus' in ponds blamed on tide. Philippine Daily Inquirer, p. A9.