The giant freshwater prawn in the Philippines (Macrobrachium rosenbergii), locally known as ulang in Tagalog and Hiligaynon, is a valuable aquatic product that if properly managed, can provide good profit.
The Bureau of Fisheries and Aquatic Resources (BFAR) has been introducing this valuable freshwater product to fish farmers, but not many Filipinos are aware of how the ulang is properly managed in captivity.
Giant Freshwater Prawn Description
Freshwater prawns can be found in many rivers and lakes in the Philippines but because of habitat loss, catching them from the wild is no longer profitable. The prawn can grow up to 30cm (12inch) in length and can weigh up to a kilo. They are predominantly brownish in color but can vary. Smaller individuals may be greenish and display faint vertical stripes. The rostrum is very prominent and contains 11 to 14 dorsal teeth and 8 to 11 ventral teeth. The first pair of walking legs (pereiopods) is elongated and very thin, ending in delicate claws (chelipeds), which are used as feeding appendages. The second pair of walking legs are much larger and more powerful, especially in males. The movable claws of the second pair of walking legs are distinctively covered in dense bristles (setae) that give them a velvety appearance. The color of the claws in males varies according to their social dominance.
Females can be distinguished from males by their wider abdomens and smaller second pereiopods. The genital openings are found on the body segments containing the fifth pereiopods and the third pereiopods in males and females, respectively.
Farming Status of Giant Freshwater Prawns in the Philippines
On average, farmed ulang weighs from 30 to 100 grams, which translates to 10 to 25 pieces per kilo. This is very much comparable to the medium to large or jumbo sizes of brackishwater tiger shrimps or sugpo. In the wild, ulang grows as much as 800g to a 1 kilo and sells at P450 to P700, however, the quantity harvested is limited and is dependent on its seasonality.
Despite the development of both hatchery and grow-out technologies for ulang, there is really no significant commercial production in the country yet, except in BFAR-operated hatcheries in Muñoz and in Dagupan. To date, the only private ulang hatchery is MBL Farms producing up to 150,000 PL or post-larvae per run (45 days), although there are entrepreneurs trained in Muñoz who are also operating small backyard hatcheries for prawns.
With the emerging global market for this giant freshwater prawn coupled with improved technologies, it is imperative to speed up the development of the industry in the country. However, the industry is faced with problems and constraints that include:
- insufficient breeders
- insufficient supply of post-larvae or PL for stocking
- limited market supply
- limited funds for interested stakeholders
- insufficient information
- inadequate promotion of technology transfer
- very few skilled and/or trained technicians
- research and development of ulang hatchery and grow-out are still wanting new technologies
Growing Giant Freshwater Prawns
Unlike tiger shrimp which require regular screening for diseases and facilities to keep out viruses and bacteria, freshwater prawns in extensive culture are mostly content with proper nutrition and good water quality. However, prawns are carriers of shrimp viral diseases as well, and thus farmers should still be careful not to pass on viruses to nearby shrimp farms.
Farmers can use simple ponds, cages, or even rice fields. “Cage culture is suited for marginalized fish farmers who have no land to develop into ponds and requires minimal start-up investment,” shared Dr. Maria Lourdes Aralar, a SEAFDEC retired scientist who largely developed the technology for lake-based cage culture.
The simplicity of freshwater prawn farming means it is widely farmed across Southeast Asia such as in Vietnam which produced 547 thousand tons in 2014 with Thailand coming a far second at 17 thousand tons. However, Philippine farm production in 2014 was only 9 tons although 1,700 tons were sourced from the wild.
BFAR’s Techno-Demo Projects in Cauayan, Isabela produced 150 kg in 500 m2 ponds after a 4-6 months culture period. The cost and return analysis for this Techno-Demo. Although this study had been done years ago, the result shows that the farming of ulang is highly profitable as they were able to get a net profit of P25,900.
In 2012, I bought 200 pieces of ulang juveniles from a BFAR employee. Had an aquaponic plastic drum with two tanks before and I place the ulang there. The limited resources online prompted me to feed the ulang with different types of foods including kitchen scraps, but mostly floating fish feed. They are highly cannibal so enough substrate should be added if you are raising them in limited space.
After around 6 months, around 60 pieces were left but some of them were really big. I harvested around 7 kilograms of freshwater prawns from 2 plastic drum aquaponics tanks. Breeding is not possible though unless you have brackish water that’s why juveniles must come from hatcheries that are experts in breeding.
The potential to make money with giant freshwater prawns is really high but many farmers don’t want to take risks because of the lack of experience and enough education and government support.
If you have at least 500 square meters of fishpond, I suggest you try farming this freshwater prawn species.
Where to Buy Freshwater Prawns in the Philippines
Today, hobbyists are getting active on social media so it is not really difficult to find freshwater prawn juveniles in the country especially if you want to experience them first. There are several groups on Facebook that talk about and trade freshwater prawns and even Australian red clay crayfish and other crawfish species. Tiger prawns are always available in limited quantity but if you want to do commercial farming, you can always contact BFAR Calabarzon Regional Office at Los Baños, Laguna, or their hatcheries in Rizal.
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