Persistent red tide in Tagbilaran Bay needs engineering solution – BFAR

HAB SOLUTION.  (From left) BFAR7 regional director Mario Ruinata and assistant director for technical services Isidro M. Velayo Jr. (PIA Bohol)

TAGBILARAN CITY, Bohol (PIA) — The Bureau of Fisheries and Aquatic Resources (BFAR) is pushing for alternative livelihoods in the form of fish cages for fisherfolks affected by the persistent harmful algal bloom (HAB), commonly known as red tide, in Tagbilaran Bay.

“The fish cages could be deployed in areas away from the affected waters, so the fish could be free from contamination,” said BFAR assistant director for technical services Isidro M. Velayo Jr.

This move is seen as a temporary solution to address the longtime red tide problem affecting the bay’s gleaning areas.

BFAR said an engineering solution is the most appropriate and sustainable solution to the growth of red tide algae blooms in the affected areas.

Both Velayo and BFAR regional director Mario Ruinata agreed that unless the flow of water is facilitated to drain the artificial lagoon, the problem would continue.

POOLED WATER

BFAR noted that the red tide in Tagbilaran Bay, which is mostly confined inside the artificial lagoon land, is caused by the pooled water after the land bridges leading to Borja Bridge in Dauis-Mansasa Junction and the Causeway Bridge in Poblacion I restricted the draining flow of the tides.

Both bridges feature long land bridges or causeways, broken only by a short span to allow the tides to pass in and out of the artificial lagoon.

However, the exits are too narrow to allow the free flow of water.

This also causes most of the tide water in the lagoon to quickly pass through and follow a strong current that moves out of the other bridge, leading the water away from the current to normally swirl on the sides and keep the algal bloom contamination within the lagoon.

“This is the reason why the red tide has not been eliminated in the waters there,” said Velayo.

Ruinata also pointed out that the HAB is also possibly fed by improper solid waste management in the area.

The coastline of the artificial lagoon from Tagbilaran City to Dauis is heavily populated, while storm water also drains into the lagoon.

PARALYTIC SHELLFISH POISONING

On March 15, BFAR issued Shellfish Bulletin No. 05, Series of 2024, warning people living in areas affected by red tide to be aware of Paralytic Shellfish Poisoning (PSP).

PSP is a syndrome that people can develop if they eat seafood contaminated by a red tide.

The bulletin, which also mentioned the coastal waters of Dauis and Tagbilaran City to be affected by PSP, warned against consumption of all types of shellfish and shrimp gathered in the affected areas.

Shellfish and shrimps are bottom feeders that feed on the affected algae, which could be toxic for humans.

The Tagbilaran City government initially provided relief assistance to shellfish gatherers who lost their livelihoods due to the Red Tide ban, but this has since stopped.

The municipal government of Dauis also implemented an assistance system during the first few years of the identification of the PSP.

In a separate interview during one of his visits to Bohol, former Public Works Secretary Mark Villar said there was a plan to introduce culverts along the entire stretch of the land bridges to facilitate the flow of water and introduce more outlets for the proper drainage of the artificial lagoon.

The plan, however, did not push through after Villar was replaced as DPWH secretary.

While an engineering solution has yet to be implemented, Ruinata said all they could do is keep monitoring the HAB levels in the area and publish the information immediately.

BFAR provincial fishery officer Candido Samijon said they will also ask local research institutions to look into the Tagbilaran Bay waters so they can guide the government on what to do to flush out the red tide. (RAHC/PIA7 Bohol)