Evaluation of the biomass and distribution pattern of target and indicator fish species in Zaragosa Marine Sanctuary, Badian, Cebu, Philippines : its implication to coastal resource management / by Joselito Francis A. Alcaria.

Thesis (Master of Science in Marine Biology) University of San Carlos

Includes bibliographical references.

The population densities, biomass and distribution pattern of “Indicator” and “Target” fish species inside and outside the Zaragosa Marine Sanctuary in Badian, Cebu, Philippines have been evaluated from April to September 2000 after more than a decade of protection. Four 50-meter transects were laid perpendicular to the reef crest at two depths: 3-5 meters and 8-10 meters in the marine sanctuary with an aggregate area of 2000 m’. The same sampling size and method were followed outside the sanctuary, which serve as the control area.

Results of the fish visual census using SCUBA over a six-month monitoring identified a total of 17 indicator species and 56 target species belonging to six families inside the sanctuary and 18 indicator species and 40 target fish species belonging to six families outside the sanctuary. Fish species inside the sanctuary are more diverse than outside and differ significantly. Within the sanctuary species diversity ranged from 0.73 to 0.89 at 8-10 meters depth and 1.04 to 1.28 at 3-5 meters depth which was higher at the shallow portion of the reef based on the Shannon-Weaver Species Diversity Index.

The average population density of both indicator and target species in the sanctuary was 1,462 ind/2000m? while outside 772.33 ind/2000m?. Population densities between the two sites differed significantly based on the t-test at 5% level of significance with t-value of 2.5339. In both sites that are inside and outside of the sanctuary, the fish population based on Morisita’s Index was aggregately distributed except in September when outside the sanctuary the distribution pattern became random. This shift in the distribution pattern was attributed to the low population counts in the non-sanctuary site.

The monthly biomass estimate of the target and indicator fish species showed an increasing trend in the marine sanctuary with two peaks, the first in July (78.46 gm/m”) and the second in September (95.44 gm/m’) with average biomass of 62.53 gm/m? or 62.50 tons/km’. Outside the sanctuary, the biomass followed no distinct pattern with a peak only in August at 25.57 gm/m? or 25.57 tons/km’ and an average of 24.87 gm/m? or 24.87 tons/km’. Fish biomass between the marine sanctuary differed significantly with that obtained in the fished area.

Findings of the study have shown that there was a positive increase on the number of species, population density and biomass estimate of target and indicator species belonging to six families as compared to the 1996 survey. New species recruits have been observed in the sanctuary while some species particularly the Lutjanidae were no longer observed in the sampling areas. In Spite these changes, the result of the t-test revealed that only the number of species between the two data sets differed significantly. The data on the population density and biomass estimate of the six families evaluated were not significant. This implied that the resources in the sanctuary are being protected and maintained and there are no indications that the sanctuary area has been disturbed due to human activities,

Other parameters monitored during the study are dissolved oxygen, salinity and surface water temperature both inside and outside the sanctuary. All values were within the normal limits set by the Department of Environment and Natural Resources. Human Pressure Index observed in the whole Badian Bay where the marine sanctuary is located include the encroachment of a commercial mariculture industry that displaced some marginal fishers from their traditional fishing ground and the unabated illegal extraction of beach sand along the coastal zone which threaten the important habitats of the bay.

The economic status of the fishers in Zaragosa Island based on the gross monthly income from fishing (2 4,116.19/month) showed that most of the fishers are living above the poverty threshold set by NEDA in 1997 at B 4,107.00/month for a family of six living in rural areas in Central Visayas. The fishery profile of the area showed that there are six types of fishing gears used by the Badian Bay fishers and the commonly used is fish net. The average fishing trip per week by the fishermen is 5.11] trips spending an average of 6.66 hours per trip. The average fish catch per trip is 5.535 kg and are sold directly to Badian Public Market at B 40-60 per kilogram for medium size fish.

Majority of the respondents perceived that the marine sanctuary has enhanced fish diversity in the area, increased fish catch and attracted guests and visitors. They also perceived that control and management of the area are shared responsibilities of the community. Other positive impacts perceived are the socio-economic conditions had improved, their skills and capabilities to become confident were developed and their environmental awareness enhanced.

Submitted to the University Library 08/04/2020 T-5987