Coral bleaching in some parts of Tubbataha Reef has been observed from May to June as the corals may have been stressed by changes in conditions such as temperature, light, or nutrients, according to the monitoring results released by the Tubbataha Management Office (TMO) last July 13.
During the annual fish and coral monitoring in Tubbataha from May 26 to June 2, TMO researchers observed some coral bleaching in the permanent monitoring sites in the vicinity of Kook, Delsan Wreck, and Jessie Beazley Reef.
Fire corals (Millepora) were the most affected in these sites, the researchers said.
The coral colonies observed at the time were not completely white in color but were only partially bleached, they said.
However, the team said two massive corals (Porites) near the dive site Terraces were completely bleached.
In its monitoring conducted from June 23 to 24, the TMO researchers observed that other kinds of corals have turned from florescent to completely white in color.
“These include encrusting (Isopora), branching (Stylopora, Poccilopora, and Millepora), foliose (Montipora), massive (Goniopora), solitary corals (Fungia), and even soft corals in most sites in Tubbataha,” they said.
“Coral bleaching was observed in patches,” they added.
Citing the Philippine Coral Bleaching Watch’s five-point bleaching scale, the TMO said the severity of bleaching in the North and South Atolls can be considered mild to moderate (Category 1 to 2), while bleaching can be described as moderate (Category 3) in the eastern side of Jessie Beazley Reef.
They further observed that behind the ranger station inside the lagoon are varying degrees of bleaching among branching and tabular (Acropora), massive (Porites), solitary (Fungia), and other kinds of coral.
“Some of the corals have started to show signs of stress, turning florescent, while others were completely white,” they said.
The severity of bleaching in the lagoon was described as moderate (Category 3).
They noted that coral bleaching was observed between the depths of two to 15 meters, with water temperature between 300 to 310 degrees Celsius.
A bleached coral is not yet dead and can bounce back when conditions become bearable and tolerable.
But if faced continuously by stressors, bleached corals could die in the long run.