Rock mounds as rock oyster (Saccostrea cucullata von Born, 1778) bed in an intertidal zone

Abstract

Rock oyster (Saccostrea cucullata) or “sisi” are mostly gleaned from natural beds usually in a distant island. This limits the access and put gleaners, mostly women to risks. There is high demand of rock oyster and supply from the wild is not enough. There are various methods that have been tested to improve supply of raw materials however there have been no success. The paper explored the use of rock mounds as oyster bed in the intertidal zone of Catbalogan City. The peak of spawning in the rock mounds occurred in May. The length-width measurements were ranging from L=1.50-5.99 and W=1.0-5.49 cm, respectively; with mean L = 3.815cm; mean W=3.003cm. With a total surface area of 322.85 m², it produced a biomass at ~ 38.243kgs. Dominance and diversity indices were determined from a total of 62 quadrat samples. Overall mean of rock oyster settlements was at 328.2/m² with 99% relative abundance from a total of 20,546 individual samples, rock mounds were considered as effective growing cultch. The results also showed that it created relatively new biotic community, but Shannon diversity index (H’) ~0.071, and evenness index (e) ~0.028, showed <1.0, low value of indices of the community structure. Rock mounds are proven to be a better alternative in rock oyster farming. It was also found out that it also acted as coastal protection structure, serving as a breakwater.