Ma. Junemie Hazel Lebata-Ramos1, Cleresa Dionela1, Schedar Rose Novilla2, Jonas Mediavilla1, Rema Sibonga1, Ellen Flor Solis1 and Frances Patrick Alicante1

1Southeast Asian Fisheries Development Center, Aquaculture Department (SEAFDEC/AQD)
Tigbauan, Iloilo 5021, Philippines

2Department of Social Welfare and Development, Regional Office 6, Molo, Iloilo City 5000, Philippines

E-mail: jlebata@seafdec.org.ph

Keywords: Crassostrea iredalei, single oyster, pouch, SEAFDEC/AQD

Oysters are a gourmet and luxury food in developed countries but a cheap food in developing countries. In the Philippines, they are among the most in demand bivalve species because of their affordability to the low-income members of the society. Because of the high demand for the commodity, oyster farming is an important source of livelihood in many coastal communities in the country.

Oysters are among the most preferred species for culture in estuarine bays because they don’t require large capital—the spats are readily available in the wild; they don’t need to be fed; and growing them requires very minimal maintenance. Among the most established methods for oyster farming in the Philippines are the stakes, and hanging oyster shells and tyres from fixed bamboo structures or floating rafts. All these traditional methods produce clustered oysters of varying shapes and sizes.

To improve marketability of oysters, two new culture methods (pouch and tray) were tested and the products compared with two of the existing/traditional culture methods (hanging oyster shells and tyres) commonly used. Using wild spats of the slipper oyster Crassostrea iredalei, the result of the experiment showed that pouch was the best method among the four tested. Oysters with an initial size of 2.3-9.1 cm shell length (SL) (means±SE = 5.3±0.02 cm) and 2.9-77 g body weight (BW) (means±SE = 21±0.22 g) and approximately 2-3 months old from settlement were harvested after 6 months of culture, instead of the usual 12 months using traditional methods.

Harvested oysters ranged 4.7-14.7 cm SL (means±SE = 8.9 cm) and 25.7-190.2 g BW (means±SE = 87.7±0.70 g). This new method produced single oysters that are meatier, juicier and almost of uniform shapes and sizes. Using the Pacific Oyster Grading System of the Australian Seafood Cooperative Centre, 60% of the oysters harvested from pouch belong to the large and jumbo sizes. Published papers reported a 5-21% flesh to total weight ratio for oysters. On the other hand, growing single oysters, resulted to an average of 24% flesh to total weight ratio (range = 11-38%). Survival was also high at 95.2%.