Status of Windowpane Oysters (Placuna Placenta) at Municipality of Tigbauan, Iloilo, Philippines

Abstract

The Windowpane oysters (Placuna Placenta) are considered as shells which have high quality value. These shells are used as raw materials for shell craft products (SEAFDEC, 2006) like chalk, shells, soldering lead, and paint (Ingole & Clemente, 2006). Furthermore, windowpane oysters were identified as second priority mollusk species for research, which located at the Philippines. In this connection, Philippines is a major source of windowpane shells fishery as cited by Madrones-ladja, 1997. Therefore, this study aimed to determine the status of windowpane oysters (Placuna Placenta) at the Municipality of Tigbauan, Iloilo, Philippines. Using the Line Intercept Transect (LIT) technique (English et al., 1997), the windowpane oyster shells (Placuna Placenta)were determined. At each site, 2-3 transect lines were laid on the intertidal floor parallel to the shore. For the physico-chemical measurements: water temperature was measured using thermometer; the transparency of the water was assessed using secchi disc; salinity and pH were measured using refractometer and pH meter; and the dissolved oxygen was measured using Winkler’s methods. Windowpane shells were collected randomly in the proposed site. Meristimatic measurements like length, thickness of the shell, and width are measured using measuring board. The data collected were analyzed to get the biometric relationship. The number of oyster increases as substrate from muddy-sandy to soft muddy slowly changes as depth increases. Common windowpane oysters found are juvenile (31- 45 mm) and having a shell thickness of 1.89 mm. The length-width relation and length-shell thickness relation are highly related, with an r value of 0.9439 and 0.5872, respectively. The populations of the site are mostly juvenile, which imposing a windowpane oyster sanctuary in it natural bed is highly recommended.Keywords: Marine Ecology, windowpane oyster, assessment, sanctuary, length-width relationand length-shell thickness relation, Southern Central Iloilo, Philippines