After Snake Island was closed to the public, the Ecosystems Research and Development Bureau (ERDB) assessed in 2016 the condition of the island’s marine resources, and continuously monitors the post-coral bleaching in the Island.

The Island, located in Honda Bay, Puerto Princesa, Palawan, was closed in 2012 following its inauguration as DENR’s National Coastal and Marine Center for Research under the DENR Administrative Order (DAO) 2011-12.

During the assessments, a natural phenomenon called coral bleaching occurred in the 7.5 hectare snake-shaped island as a result of elevated seawater temperature.

According to Mr. Jose Isidro Michael (Jim) Padin, Supervising Science Research Specialist of ERDB, the change in temperature made the corals expel algae living in their tissues called zooxanthellae which give corals their color. This causes their appearance to turn pale white.

“However, the corals do not die right away because of bleaching,” Padin quipped. He explained that hard corals can survive a bleaching event and return to their normal state unless unfavorable conditions continue for a prolonged period of time.

Post-coral bleaching

After two years of monitoring, ERDB’s research team discovered that significant portions of the reef are providing spaces for settlement of young coral colonies. However, some parts have been found to have a high algal cover which is known to hinder the recovery of affected corals.

Padin cited that rapid succession of algae on reef structures might be caused by the reduced population of herbivorous or plant-eating fish species coupled with an influx of excess nutrients from nearby tributaries. He adds that algal-feeding fish, such as the parrotfishes, siganids, acanthurids, and wrasses among others, were observed but they must be constantly protected from fishing to increase their meager numbers.

The assessment found out that exhaustive fishing in the area resulted in the decline of algae-feeding fish, leaving no natural control measure for the increasing algal growth. ERDB, along with other stakeholders, subsequently called out to local fishermen and the LGU of Palawan to propose a demarcation for no-fishing zones to facilitate the reef’s rehabilitation.

According to the ERDB Director, Dr. Sofio B. Quintana, “in order to protect the Island and to help in the recovery of the corals in the area, there is a need to delineate areas for fishing and non-fishing. This will allow the coral reefs to recover”.

Emerging issue

Another factor which can hinder the recovery of the coral reef is the growing population of sea stars, Acanthaster planci (Linnaeus, 1758). These sea stars belong to a species which feed on healthy coral polyps leading to the bleaching of some Acroporid corals. The outbreak of sea stars may be caused by increased nutrients in the water or the removal of its predators, or both.

The ERDB research team is continuously monitoring the population of the sea stars and is looking at the possibility of resorting to the necessary control methods such as manual removal or induced death.

Preliminary findings of the ERDB team have been presented last January 10-11, 2018 to concerned stakeholders which include the Bureau of Fisheries and Aquatic Resources (BFAR), DENR-CENRO Puerto Princesa City, DENR-PENRO Palawan, Environmental Management Bureau (EMB), Palawan Council for Sustainable Development (PCSD), Puerto Princesa City Tourism Office, and the Puerto Princesa City Environment and Natural Resource Office (City ENRO).

Among the solutions discussed were science-based coral transplantation, restocking of herbivorous fingerlings, and the continuous monitoring of water and other marine resources of the island.

A fishing moratorium to increase fish population in Snake Island has also been up for discussion. This is also seen as a long-term solution for the reported decline of fish stocks in Honda Bay.

ERDB Director Dr. Quintana assures that ERDB will continue to provide science-based information which will help in protecting the natural beauty of Snake Island.