MARINE RESERVES INDICATE LOW FISH POPULATION

Corregidor Sanctuary Shows Redeeming Performance

A summary of the survey of coral reefs by Silliman University and the Australian Research Centre of Excellence for Coral Reef Studies, James Cook University, Australia, under the “Bohol Sea Marine Reserves and Connectivity Project.”

Coral reefs are natural food factories. With their continued decimation, our fish gets smaller, fewer, and more expensive. Saving strategic reefs could demonstrate the role of conservation.
Sampling surveys were conducted on 30 August to 7 September 2006 at 11 reefs in Surigao del Norte: 2 in Dinagat, 4 in Siargao, 5 in Surigao City. Target reef fish biomass, or the collective weight of fishes per unit of area of coral reef, ranged from 10 tons per sq km at Union (Dapa) and Corregidor in Casulian Island, Dapa.
The biomass values found in Surigao del Norte reefs were a small fraction of the biomass recorded for areas that have benefited from a significant duration of protective management using no-take marine reserves as in the case of Corregidor Marine Sanctuary, which was established in 1998.
Surigao del Norte reefs had less than 3% of the target fish biomass recorded for Balicasag Marine Reserve in Bohol, a reserve established for 21 years. At best, the reefs in the province had only 18% of the target fish biomass recorded for Bil-isan Reserve in Bohol, a relatively young marine reserve established 4 years.
The low biomass found for Surigao del Norte reefs was considered as not the result of poor habitat condition, but rather, of overharvesting.
Overfishing. Predatory reef fishes belonging to the families of groupers (baghak, pugapo), jacks (langog) snappers (maya-maya), emperors, (dugso) contribute significantly to the standing stock on healthy coral reef. Top predators are the first to disappear from an overfished reef.
In the reefs of Surigao del Norte, this group of fishes was practically absent, indicating overharvesting. There are however, indications of potential recovery of these important target fish in some areas if protective management is enforced.
Destructive fishing. Blast fishing was actually noted at the time. In the surveys in Casulian Island (Dapa) an average of 1 blast every 15 minutes during the dive. Anecdotal information revealed fishers now employ regular household bleach to catch octopus from reefs.
Options. Numerous studies have shown that with effective, long–term protection from fishing, populations of exploited species can recover dramatically inside a no-take marine reserves (Russ 2002). Increased abundance of target species inside marine reserves is expected to benefit fisheries outside reserves through the net export of adult fish or spill over, and larvae recruitment subsidy, expected to occur within hundreds of meters of reserve boundaries within the barangay or municipality, while recruitment subsidy could occur over tens to hundreds of kilometers within the province and beyond.
Local spillover benefits may prove important in convincing communities to support establishment and protection of marine reserves.