The CAO attributed the fish kill to "aquatic stratification."
A report submitted by CAO chief Jose Gil Parreñas said, "emphasis is necessary for the regular monitoring of the seepages that mixed up with the water flowing towards the Calajunan Creek as this tributary is directly above the area that was greatly affected."
In earlier interview, Mayor Jerry Treñas ruled out the possibility that a seepage from the Calajunan dumpsite which passes through the Calajunan creek could be the reason behind the fish kill. The mayor, however, was not yet equipped with Parreñas's report during the interview.
The affected areas was recorded from Barangay Sooc, Arevalo to Mandurriao along B. Aquino Bridge until Jalandoni and Forbes Bridges. Both the fishermen and nearby residents were greeted Saturday morning with dead gobies, eels, tarpons, crabs, shrimps, catfishes and tilapia. Before these fishes and crustaceans were seen floating in the river, they showed common signs of surfacing and gasping behavior.