DAGUPAN CITY, Feb. 5 (PNA) — Red tide, caused by harmful algal bloom during sunny months when the salinity of water is unusually high, is closely related to fish kill.
This was bared by Dr. Westly Rosario, chief of the National Integrated Fisheries Technology and Developmenf Center in Dagupan City.
In 2001, said Rosario, there was a big fish kill that occurred in Bolinao and Anda, two big milkfish-producing areas in western Pangasinan.
“We in the center believed it was caused by the depletion of dissolved oxygen in the water, particularly along the Caquipotan Channel.
The University of the Philippines Marine Science Institute (UPMSI), which has a marine laboratory in Bolinao, believed more than this factor.
UPMSI insisted that the cause of the fish kill was the harmful algal bloom that eventually died off in the water and when it rotted caused red tide toxin. The red tide organism consumes dissolved oxygen, leaving a little for the fish in captivity.
Rosario recalled that it was in 2001 when the first episode of red tide was felt in Bolinao. The seeds of red tide eventually spread to the neighboring town of Anda, Wawa, Bani; and Alaminos City.
“After red tide was introduced in Pangasinan in 2001, we cannot lick this anymore. Since we can not remove this anymore, we have to learn to live with it,” he said.
Incidentally, said Rosario, the just concluded red tide episode was the longest ever felt in western Pangasinan as it lasted for more than four months. Previous episodes lasted for just one month, he noted.
He said the length of time that red ride lingered on may have something to do with the heavy deposit of organic nutrients along tne Caquipotan channel, where many fish cages for milkfish are located.
Thus, Rosario reiterated his previous recommendation for fish farmers along the Caquipotan channel to relocate their fish cages in the meantime to ensure the flushing of organic nutrients deposited in the bottom of the water after decades of human activities.
The organic nutrients fertilize the algae in the water and allow them to bloom. When they die off, red tide occurs soon, said Rosario.
“The ball is now in the hands of the local government units, whether they will heed our recommendation or not. If they will, red tide episodes each year may be shorter,” he added. (PNA)