Puerto Princesa Bay is still infected with the presence of “red tide” since May 2, 2019 that banned gathering, selling and eating of all types of shellfish from the bay, and the ban remains until present, an aquaculturist said.
“Hanggang ngayon ay hindi pa na-lift. May red tide pa tayo. Itong Puerto (Princesa) Bay,” Joven Delgado, aquaculturist of the City Agriculture Office told Palawan Daily News.
The latest was issued on October 15, 2019 through the Shellfish Bulletin No. 18 signed by Bureau of Fisheries and Aquatic Resources (BFAR) Undersecretary for Fisheries, Commodore Eduardo Gongona.
This means that the latest laboratory results showed that the shellfishes collected are still positive for paralytic shellfish poison that is beyond the regulatory limit.
Since the issuance of six other shellfish bulletins since June 28, 2019 until the latest this October, Puerto Princesa Bay has been identified and included among the areas positive of Red Tide along with other bays in the provinces of Bohol, Leyte, and Samar.
On May 2, 2019, though Puerto Princesa Bay was not included in the shellfish bulletin issued by BFAR, a Local Red Tide Warning was issued by the Office of the City Mayor, to safeguard human lives while waiting for the result of the Confirmatory Test of Shellfish Samples.
The warning signed by city administrator, Atty. Arnel Pedrosa, said that this was based on the laboratory examination conducted by the Palawan Red Tide Testing Center located in E. Valencia St.
Sometime last December 2018, a warning was issued through Shellfish Bulletin, therefore during the onset of 2019, Puerto Princesa Bay was still positive of Red Tide or HAB. This was only on February 7, 2019, when Undersecretary Gongona issued an advisory that Puerto Princesa Bay was negative for red tide toxins or Paralytic Shellfish Poisoning.
Delgado explained that as a protocol, if a specific area is declared as positive of Red tide toxin, a weekly test and sampling is made. If it yielded three negative results from red tide toxins during the laboratory test, that will be the only time that the shellfish ban and warning will be lifted.
He further said that red tide is caused by organisms that multiply in the seawater.
“Ang red tide ay sanhi ng mabilis na pagdami ng mga organismong tinatawag na dinoflagellates kaya tinatawag itong Harmful Algal Bloom (HAB).
He further said that the dinoflagellates is a small organism belonging to kingdom Protista. It can only be seen through a microscope. It is similar to a plant which will bloom if there are plenty of nutrients.
“Ang sobrang pagdami ng sustansya sa tubig, particular ang nitrate at phosphate ay maaring sanhi ng paglitaw ng red tide o pagkakaroon ng HAB,” Delgado explained.
He further said that HAB is triggered by nutrients present in the seawater. He said that this July 2019, after a long dry season, it was followed by rains, when there are surface water runoff from the upland that drains towards the sea.
“Sa ganitong sitwasyon nagiging mayaman sa sustansya ang tubig alat na nagiging sanhi ng pagdami ng dinoflagellates,” he said.
Other factors that contribute to the increase of the population of the organism are low salinity of seawater and high surface temperature of seawater. He further said that the absence of wastewater treatment is also a factor that contributed to HAB, since dirty water is drained towards the sea.