Watch your calendar. This was the advice of the Bureau of Fisheries and Aquatic Resources to owners of fish ponds and pens in Pangasinan to avoid losing their cultured bangus (milkfish) to fish kill. Regino Regpala, chemist of the BFAR research center here, said owners and caretakers of fish ponds and pens should watch the calendar for the schedule of neap tide when fish kills are likely to occur. Neap tide is characterized by very minimal tidal changes that there is almost no water movement, causing low level of dissolved oxygen in the water. It occurs when the moon is on its first quarter and last quarter phases.

Sotelo, Y. (2010, July 3). BFAR on how to deal with fish kill: Check calendar. Philippine Daily Inquirer, p. A15.