Bamboo raft technology boosts oyster harvest

Traditionally, oyster culture is done in shallow estuarine water using tulos or bamboo stakes attached with discarded oyster shells or sliced tires to collect spat and grow the oysters. This method takes seven to eight months and results in relatively small oysters at harvest and production rate of 12-15 kg oysters per square meter.

To boost local oyster production and provide additional livelihood to fisherfolk in Pangasinan, the National Fisheries Research and Development Institute (NFRDI) introduced the bamboo raft technology to oyster-producing fisherfolk associations in five municipalities of Pangasinan–Alaminos, Bani, Bolinao, Anda, and Sual, collectively known as ABBAS. 

The technology uses bamboo as rafts with plastic drums as floaters. Attached vertically to the raft are plastic straps where oyster spats can attach and grow. It is also a mobile structure which can be transferred to another site when necessary.

The NFRDI, in collaboration with BFAR-National Fisheries Development Center, conducted a hands-on training on the construction of floating bamboo rafts for spat collection and growing oysters. Each identified association in the five sites were provided with 20 floating bamboo rafts for growing oysters and bamboo rafts for spat collection. Some of the associations also constructed floating huts for sorting, weighing, and packing of oysters in the site.

“This is a better culture method for oysters because the straps where the oysters are attached do not touch the bottom of the water. It should be at least 1.5 meters above bottom during the lowest low tide. This is the reason oysters are cleaner, with little or no sand in the shells, and can easily detach from straps at harvest,” explained project leader Dr. Joseph Rayos.

Rayos added, “culture period is also shorter in the floating bamboo rafts. Within five to six months, 22-24 kg oysters per square meter or 1,000-1,300 kg oysters per raft can be harvested. The size is bigger because the oysters get more nutrients from the natural food circulating in the water.”

Fifty seven-year old Teodorico Boton, a resident of Baleyadaan, Alaminos City, is a frequent trader of oysters.  Every day for almost six years, he buys several sacks of oysters at the Alaminos project site. “The good-size (big) oysters cost PhP 1,000/sack while the bad-size (small) oysters cost PhP 400/sack. I now order oysters from the project partner, Baleyadaan Fisherfolk Association, because I have seen that oysters cultured in the bamboo rafts are of better quality than oysters cultured in the traditional method. I sell this to oyster sellers along the road in Lucao, Dagupan, which they pay in cash two or three days after delivery,” said Boton.

Michael Bautista, president of the Samahang Magsasaka at Mangingisda ng Baley-adaan, Alaminos City, Pangasinan shared, “October to February are peak months to market oysters. At least, 100 sacks with an average weight 30 kg per sack of good-size oysters are sold, at the most, to four traders only. But during lean months, we only have four buyers, who order five sacks of good-sized oysters and seven sacks of bad-size oysters. This really affects our income but we are still thankful since this is compensated during the peak months.”

Bautista added that during the first cropping of oysters, they were able to produce 14.5 sacks of good-size oyster and 196 sacks of bad-size oysters, with a combined income of PhP 97,150.00. Remarkably, Bautista achieved an initial return on investment of 56% for the first cropping of oysters.

Local traders are mostly the clients of the oysters produced and the local community through the Agri-Fisheries trade fair and other local events organized by the municipal government. The association hopes to reach markets outside of Pangasinan on a regular basis. (### Maria Elena M. Garces)