A significant decline in the Red Tide episode in Tambobo Bay in Barangay Bonbonon, Siaton town in Negros Oriental was noted by the Provincial Agriculture’s Office (PAO) in its latest testing, however, the alert level still remains in effect against human consumption of shellfish.
Wilmencita Pialogo, a marine biologist of the Provincial Agriculture’s Office (PAO) and team leader of the Provincial Red Tide Task Force, disclosed Tuesday that the latest laboratory tests on water samples from Tambobo Bay on Monday showed a significant drop in the density of the Red Tide organism, pyrodinium bahamense.
But she cautioned that water sampling results vary with the bio assay, a laboratory test, of shellfish meat collected from the contaminated waters of the bay.
Pialogo disclosed that the Siaton municipal agriculturist’s office already took shellfish samples from Tambobo Bay, which will be sent to Cebu for forwarding to the central office of the Bureau of Fisheries and Aquatic Resources (BFAR) for bio assay testing.
The level of toxicity of the Red Tide event at Tambobo Bay will be determined through the bio assay, thus for now, residents in the area are still advised not to collect and eat shellfish from the bay.
Red Tide, also known as algal bloom, becomes potent during high concentrations of nitrates and phosphates, usually associated with agricultural run-offs or water leaving farm fields and carrying with them substances such as fertilizer.
It is the BFAR central office that has the authority to declare whether Tambobo Bay is free of the Red Tide episode, depending on the result of the bio assay, said Pialogo.
According to Pialogo, they are also looking further into the presence of this particular type of organism, pyrodinium bahamense, which she describes as something “new” and not previously seen here.
The pyrodinium bahamense is a “potent species”, she added.
On July 26, the red tide occurrence of increased level was first monitored following sampling taken from at least three areas in Tambobo Bay, where private yachts and other fishing vessels are docked or anchored.
Pialogo disclosed that laboratory sampling showed a high level of density of the red tide organism at 219 micrograms SPX per 100 grams of shellfish meat tested.
The tolerable level is only pegged at 60 micrograms SPX per 100 grams of shellfish, she further disclosed.
Initial testing also showed the presence of what she describes as a “potent species” of the Red Tide toxins that have contaminated the water and the shellfish in the bay area.
By July 31, another sampling was once again done as part of their regular weekly monitoring of the Red Tide event, also known as algal bloom, said Pialago.
When asked what had caused the algal bloom, she said she believes it was agricultural run-offs, such as fertilizer from the sugarcane fields following continuous heavy rains that may have triggered the Red Tide event.
Pialago explained that red tide organisms are present everywhere but at a tolerable level that would not pose harmful effects to humans or animals.
However, when the presence of nitrates and phosphates are at higher levels, they trigger algal blooms that cause Red Tide to occur.
So far, authorities have not received reports of people coming down with shellfish poisoning in the area.
As for fish consumption, residents in Tambobo Bay and nearby areas are advised to properly clean the fish taken from the bay by removing its gills and guts. (Judy Flores Partlow/PNA)
