No shield for corals in storms
Dr. Angel C. Alcala
With the coming of the typhoon season in the Philippines, a national scientist has expressed concern over the damage to coral reefs, particularly in marine protected areas (MPAs).
The southern Philippine area has the most number of marine reserves in the world, but it is also hit by four typhoons between 2008 and 2013, compared to only two typhoons in the 24-year period from 1983 to 2007, Dr. Angel C. Alcala of Silliman University-Angelo King Center for Research and Environmental Management (Suakcrem) said.
Two of these typhoons—“Sendong” and “Pablo,” which hit the country in December 2011 and in December 2012, respectively—destroyed the MPA of Apo Island off the coast of Dauin town in southern Negros Oriental province.
“The coral reefs—the habitat of fish—were also destroyed,” he said during the Forum on Climate Change, Poverty and Development organized by Silliman and the Oscar M. Lopez Center for Climate Change Adaptation and Disaster Risk Management Foundation Inc.
The Apo Island marine sanctuary has been protected from fishing since 1982. It was generating 150 tons of fish catch per kilometer before Sendong.
“The more than 25 years of protection of the marine sanctuary on Apo resulted in 27 times more biomass, and 11 times more species of large predatory fishes,” said Alcala, who was named national scientist by President Aquino in June 2014.
After the typhoons, Dr. Rene Abesamis of Suakcrem, Dr. Garry Russ of the School of Marine and Tropical Biology at James Cook University in Australia, and Dr. Alcala conducted a study on Apo Island and found that the marine sanctuary had “zero live coral cover” after Sendong and Pablo and 60 to 70 percent coral cover by 2008.
Through the baited remote underwater video surveys in December 2014 on Apo Island, Abesamis and his team found that the number of fish, like the yellow-tailed butterfly fish, groupers (“lapu-lapu”) and snappers (“maya-maya”), also decreased. The parrot fish (“mulmol”) survived relatively better.
Negative implications
The study found that the reduced abundance of fish and loss of biodiversity have negative implications on the aspect of food security.
Video footage at 30 to 40 meters underwater showed badly damaged coral reefs. At 40 to 80 meters deep, there were no well-developed coral reefs, and the layer of rock that could be seen consisted of dead coral boulders that rolled down the slope on the sand.
The scientists concluded that it was unlikely that the mobile predatory fish (snappers) took refuge in the deeper waters as there was no good habitat there.
Alcala stressed the need to relocate the MPA on Apo Island to the western part of the island that is not disturbed by typhoons.
The new MPA is expected to build up a high abundance of adult fishes over time, and produce larvae to sustain the abundance in the other areas of the island.
Alcala cited his earlier studies on Pescador Island off the western coast of Cebu, where 5 to 11 percent of hard corals per year (or about 45 percent of live hard corals in four years) are expected to recover, if no typhoon hits the marine sanctuary.
Another adaptation measure is for the fishers to use bamboo traps to catch fish, “instead of the habit of using steel-bar traps—which is bad,” he said.
He urged the people to stop fishing and eating parrot fish to help hasten the recovery of shallow reefs.
Competition
Parrot fish graze on algae found on chunks of corals that are torn from a reef. They pulverize portions of coral reefs to get to the algae-filled polyps.
Algae compete with coral recruits for sunlight, and would shade the coral recruits, preventing them from growing.
“If the people stop eating parrot fishes, and fishermen lay off fishing for parrot fish, there will be more parrot fish that will eat the algae that compete with the growth of coral recruits,” Alcala said.
The mulmol, which usually come in a combination of orange, yellow, green and blue, is sold for P180 a kilo in the local market because of their abundance around tropical reefs.
In Polynesia (including Hawaii), it is served raw. It was once considered “royal food” eaten only by the king.
Alcala warned on the effects of climate change on coastal waters including an increase in its acidity and an increase in its temperature. “Warm waters cause coral bleaching, or the whitening of the corals due to the loss of algae living in them,” he said.
He also warned on the rise of the sea level. “This, in turn, accelerates the erosion of beaches, the flooding of low-lying or flat islands (resulting in the displacement of people), and it favors the expansion of mangroves toward the land, and seawater intrusion into our land.”
Alcala added that climate change could cause storm surges that destroy coral reefs, “which, in turn, kill or displace fishery species and other species of marine biodiversity.”
