The culprit behind the massive fish kill in Cañacao Bay in Cavite was algal bloom, the Bureau of Fisheries and Aquatic Resources (BFAR) revealed.
BFAR Spokesperson Nazario Briguera said algal bloom is a natural phenomenon that usually occurs in nature, especially in marine waters.
“Pinatingnan din natin kung bakit nagkaroon ng pagbagsak ng dissolved oxygen level, and as of yesterday ay may inilabas na bagong resulta ang aming laboratoryo at lumalabas na nagkaroon po ng algal bloom doon sa area ng fish kill kung saan nangyari iyong paglutangan ng mga patay na isda (We also asked them to check why the dissolved oxygen level went down, and as of yesterday, a new result from our laboratory came out and it showed that an algal bloom happened in the area of the fish kill where the dead fishes floated),” he said in a televised media briefing on Thursday, Nov. 17.
According to the BFAR official, algal bloom happens when there is an increase of micronutrients in the water.
“Ito po iyong nangyayari kung bakit nagkakaroon ng algal bloom at kapag may algal bloom po, ibig sabihin dumami iyong mga micro algae doon sa tubig, nagkakaroon po ng paghigpit ng oxygen. So ito pong dissolved oxygen kasi, napakahalaga nito para sa survival po ng isda doon sa tubig (This is what happens why there is an algal bloom and when there is an algal bloom, it means that those microalgae increase in the water, there is a restriction of oxygen. So this is dissolved oxygen because it is very important for the survival of fish in the water),” Briguera explained further.
The BFAR noted that there is no way of knowing when and where an algal bloom will occur, and when it will vanish.
“Ang tanging puwede lamang nating gawin ay magkaroon ng continuous monitoring doon sa water quality (The only thing we can do is to have continuous monitoring of the water quality),” the spokesperson added.
Briguera stated that climate change may have caused the algal bloom which killed the fishes in the said bay in Cavite.
“[A]lgal bloom kasi could be attributed to the changing of temperature, iyong pag-init, tapos biglang pag-ulan. So, doon po natin mai-attribute iyan (Algal bloom could be attributed to the changing of temperature, that warming, then sudden rain. So, we can attribute it to that),” he said.
He also said that there are literatures suggesting that one of the factors that causes algal bloom is pollution.