THE MUD CRAB (Scylla serrata) is a high-value crustacean cultured in brackish water ponds. There is a growing demand for it in the local and export markets.
By Dr. Rafael Guerrero III
In 2012, the country produced 16,359.6 metric tons of the crab, which is locally known as “alimango.” The top mud crab-producing regions are Northern Mindanao (Misamis Occidental), Central Luzon (Pampanga), the Bicol region (Sorsogon), and Western Visayas (Capiz). Live mud crab is exported to Hong Kong, Singapore, Taiwan, and mainland China.
In many areas, the mud crab is commonly grown together with milkfish and shrimp in ponds at stocking rates of 30 to 500, 1,000, and 5,000 per hectare, respectively. With artificial feeds only available for milkfish and shrimps, the crab is given ‘trash’ fish and small clams known as “gasang” as supplemental natural feeds.
The good news is that there is now an artificial feed for the mud crab. Daniel Cabrera, market creation manager of Santeh Feeds Corp., a leading aquaculture feeds producer in the country, said that Tateh Crab Feeds are available throughout the country. “Like those for shrimp feeds, we have crumble and starter feeds for ‘fly size’ juveniles and crablets, and grower, finisher, and fattener feeds for growing the crabs to market size,” he added.
In a pond trial with cooperator Jun Robles in Northern Samar, 3,000 crablets having an average weight of 44 grams were stocked in a hectare and given 100% of the crab feeds. Initially, the young crabs were kept in a 40 x 20-meter pen made of bamboo poles and nylon netting within the pond to concentrate and train them for feeding. After 60 days in the pen, the crabs with an average weight of 220 grams were released and grownto a market size of 500 grams each after four months of culture. With a feed conversion of 0.9 kilo of feed to produce a kilo of the crab, the cost of feeding is only R50, according to Cabrera. In another pond trial with John Ong in Orani, Bataan, a pond measuring a hectare was stocked with 6,000 crablets weighing 15 grams on the average. Ten feeding trays, each measuring 1 x 1 meter, were used for checking the feed eaten by the crabs; these were stocked at the recommended feeding rates. A pond fence made of nylon netting and bamboo stakes was installed to keep the crabs from crawling out. At harvest, the crabs had an average weight of 500 grams, a feed conversion of 0.9, and a high survival rate. Crabs weighing 500 grams apiece sell for 500 to 650 pesos per kilo.
“The meat of crabs raised with 100% artificial feeds is more meaty and (has more) fat than the crabs fed with ‘trash’ fish,” says Ong, who serves the crabs he produces in his restaurant. “With ‘trash’ fish feeding of the crabs, the cost of producing a kilo of crabs can be more than 100, especially during the off season, when the supply of the feed is low,” Cabrera says. He adds that the continuous supply of artificial feeds can be assured, and crab farmers have found that ponds of artificially-fed crabs are cleaner because of natural feeds cause pond pollution.
For more information on the artificial feeds of the mud crab, interested readers may contact Daniel Cabrera through email (firstname.lastname@example.org).
This story appeared in Agriculture Monthly’s May 2014 issue.