Innovative Aqua Techniques from PCAARRD

By Dr. Rafael D. Guerrero III

At the recent “SIPAG ni Juan” festival of the Philippine Council for Agriculture, Aquatic and Resources Research and Development (PCAARRD) of the Department of Science and Technology (DOST) in Los Baños, Laguna, innovative technologies related to aquaculture with support from the PCAARRDDOST were featured.

“SIPAG” stands for “Strategic Industry S&T Programs for Agri-Aqua Growth.” The technologies were a seaweed-based rice growth enhancer, an automatic fry counter, the culture of a marine annelid for mangrove crab broodstock, and the production of soft-shell mangrove crabs.

Seaweed-based rice growth enhancer

Rice plants in pots treated with, and without, the Carrageenan Plant Growth Regulator.

Known as “Carrageenan Plant Growth Regulator” (CPGR), this was developed by scientists of the University of the Philippines Los Banos’ National Crop Protection Center led by Dr. Gil Magsino using irradiated carrageenan (a polysaccharide of red seaweed) produced by the Philippine Nuclear Research Institute (PNRI) of the DOST. From field trials conducted in Pulilan (Bulacan), Victoria (Laguna), and Munoz (Nueva Ecija), the plant food supplement or organic fertilizer was seen to increase rice yields by 15 to 30%.

The application of 3 to 6 bags of NPK plus 9 liters of CPGR per hectare significantly increased rice yields compared to the yield of rice fertilized with only 9 bags of NPK.It is believed that CPGR improves the growth, development, and immune system of the rice plant and makes it resistant to lodging and diseases. CPGR is also environmentally-friendly because it enhances “the presence of the natural enemies “of the insect pests of rice.

According to the PNRI, a liter of CPGR only costs 100 pesos.

The Automatic Fry Counter developed by UPV-CFOS.

Automatic Fry Counter (AFC)

The tedious, time-consuming and inaccurate method of counting milkfish fry can now be replaced by the low-cost, rapid, and accurate AFC, developed by researchers headed by Dr. Crispino Saclauso of the University of the Philippines Visayas’ College of Fisheries and Ocean Sciences in Miagao, Iloilo.

Consuming less time and causing less stress on the fry, the ATC—which consists of a counting channel, a light source (laser), receptor (phototransistor) mechanism, and a small processor, can count the fry at 6 per second. It has an accuracy of 95% and costs less than Php5,000.

Technology for the culture of a marine annelid for mangrove crab broodstock

The marine annelid (polychate) Marphysamossambica, found locally, has been bred and cultured artificially as food for the broodstock of the mangrove crab (“alimango”) by Dr. Veronica Alava and co-workers of the Southeast Fisheries Development Center’s Aquaculture Department (SEAFDEC/AQD) in Tigbauan, Iloilo.

The marine annelid cultured by the SEAFDEC/AQD.

With the high levels of total lipids and unsaturated fatty acids in  the worm, feeding it to the crab spawners as 20% of their diet improved production of the larvae (zoea) as well as their growth and survival. The worm can be fed live or as a dry meal in the feed of the crabs. It has 62% crude protein and 0.8% crude fat on a dry weight basis.

Technology for the production of soft-shell mangrove crabs: Soft-shell crabs are crabs that have just molted (change of shell) and are preserved while their new shells are still soft for cooking and being eaten whole (including shell and limbs). Such crabs are highly valued in seafood restaurants and can be exported to Hong Kong, Singapore, and Taiwan.

Newly-molted crab (right) beside its old shell. (Source: SEAFDEC/AQD)

A technology for the production of soft-shell crabs was developed by Dr. Emilia Tobias-Quinitio and co-researchers using hatchery-bred crablets (young crabs) at the SEAFDEC/AQD (Southeast Asian Fisheries Development Center-Aquaculture Department). The crablets (3-4 centimeters or cm in size) are first grown in brackish water ponds for 1.5-2 months to 60-100 grams each. Then the crabs are individually placed in perforated plastic boxes or bamboo cages that are floated with PVC pipes and fed with mollusks like the kuhol (“Golden Apple Snail”) or trash fish.

While in the floating boxes/cages, the crabs are monitored every four hours to check whether they have molted. The newly molted crabs are removed and transferred to aerated containers with freshwater for one hour to kill them and prevent their soft shells from hardening. They are then sorted, packed, and frozen for the market.

For more information on these technologies, interested readers may contact the Executive Director of PCAARRD through email: [email protected]

This appeared in Agriculture Monthly’s May 2016 issue.

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