News from the 7th Fisheries Science Conference held in Tagaytay.
By Dr. Rafael D. Guerrero
The NFRDI, based in Quezon City, is the research and development arm of the BFAR conducting studies for the “management, conservation and protection of the country’s fisheries and aquatic resources.”
Researchers of the NFRDI are deployed in its three centers, namely the National Freshwater Fisheries Research and Development Center (NFFRDC) in Butong, Taal, Batangas, the National Marine Fisheries Research and Development Center in Guiuan, Eastern Samar, and the National Brackishwater Research and Development Center in Lala, Lanao del Norte.
Frederick Muyot of the NFFRDC reported on the socioeconomics of cage aquaculture in Taal Lake, Batangas.
His survey revealed that the more than 5,000 floating cages in the lake produced 4-5 tons of fish (mostly Nile tilapia) per cage per cycle for a total of 30,877 metric tons valued at over R3.7 billion. The results also showed that cage culture operating costs ranging from R25,000 – R500,000 and a net income ranging from R20,000 – R100,000 per operator.
Researcher Maria Theresa Salamida and her co-workers at the NMFRDC studied the biology and ecology of the Asian moon scallop (Amusium pleuronectes), locally known as “tipay,” in the coastal waters of Samar and Leyte in the Eastern Visayas. They found the bivalve present in the sandy-muddy bottoms of bays and straits at depths of 6-21 meters. The species is a hermaphrodite (having both sex organs) with a shell height of 55-70 millimeters when harvested by divers. It is sold in Manila markets at R150- R200 per kilo.
Aniceto Labastida and co-researchers of the NBFRDC determined the abundance of the “agihis” (Domax sp.), a small bivalve used as a natural feed for cultured shrimp and crabs, in Panguil Bay. They found the species to have a density of 42,571 per square meter at the sea bottom. Mature clams were abundant in the months of May to August and December to February. With its populations declining due to overfishing, the researchers recommended conservation measures.
Aside from the studies of the NFRDI researchers, we also obtained fisheries information from the research conducted by workers in other institutions.
From the Mariano Marcos State University in Currimao, Ilocos Norte, Michelle De Vera and M.G. Ramos discovered that the baker’s yeast (Saccharmyces cerevisae) was an effective immunostimulant for sea bass fingerlings (Lates calcarifer) against the pathogenic bacterium Aeromonas salmonicida. By supplementing the diet of the fish with 30 and 40 grams of baker’s yeast per kilo of the feed, the mortality rate of the fish was reduced to 8.33%, compared to 100% mortality without baker’s yeast.
Researchers of the University of the Philippines Visayas’ Institute of Fish Processing Technology in Miagao, Iloilo, led by Karmelie Jane Manaya, showed that the residue remaining after the production
of oyster sauce was rich in nutritious compounds such as protein and lipids, and antioxidants that have free radical scavenging activity. The extract can be dried in powder form and used as a food or feed supplement.
Did you know that there is a new mussel (“tahong”) species in the country? It is the blue or charru mussel, Mytella charruana, according to Michael Price and co-authors. The mollusk was first found in the country in 2015 in Dagupan City and was first reported by Dr. Wesley Rosario of the BFAR. It is believed to have been introduced in Manila Bay through the ballast water of ships coming from the Western Pacific Coast of South America where it is naturally found.
Compared to the green mussel (Mytilus smaragdinus) already being cultured in the country, the researchers believe that the new species has culture potential for growing at salinity levels below 35 parts per thousand which the green mussel cannot tolerate.
This story appeared in Agricultural Monthly’s January 2017 issue.