Pangasius is an significant food fish and is farmed expansively in many parts of the world. It is one of the most important aquaculture species in Thailand, along with other farm-raised shark catfishes.
As stated earlier, it has caused much debate within the U.S., with legislation passed recently to prevent its imports from cutting into American farmed catfish sales. Prohibited to be labeled as “catfish” in the U.S., Pangasius is now labeled as “swai” (its Thai name), “sutchi catfish”, or “striped catfish”.
This fish is sometimes sold as the superior “basa”. Compared to the basa, this fish is thought to be inferior, as its meat is coarser and comes in thinner.
Despite this, swai is still common as it is much cheaper to maintain, easier to breed, and is also a faster-growing species. It is said that 90% of fish sold as basa is actually swai.
“BFAR’s concern is to study its difference from other catfish and other fish in general. They conducted a risk analysis on how safe is Pangasius as an aquaculture specie,” continued Palma.
It eats vegetable residues, rice grains (although it lowers the quality of water) It also eats fermented water hyacinth and commercial feeds. It grows bigger in a matter of six months, up to l kilo. It grows 5 to 6 grams per day. It was once called Baboy sa Tubig.
A critical stage in feeding is when it absorbs its own yolk. It becomes extra-cannibalistic when he eats all the yolk. After absorbing their own yolk sack, survival of all fries will be critical during the first three days. The cause of most mortality is cannibalism and unavailable natural plankton such as moina and artemia,
When they are young, they like to school up, but will become more and more solitary as the get older. They are generally a good community fish and can be kept with most size tank-mates.
Males are more slender than the females and have darker striping. Females have swollen round shape, soft and reddish vent abdomens, silver gray body color, and if slightly stripped, the mature female, which is ready to spawn, its yellow egg can be seen. Males have abdomens that are flat, smooth and not as big as female, vent is reddish color but not swollen. Matured male will show milt when stripped.
In 2005, the Mekong Delta produced 3 billion of larvae to be placed in their farms. In natural surroundings, the reproductive season starts from May to June. In artificial reproduction, the fish becomes full-grown and lush early through highly developed water temperature management and can lay eggs earlier than in the natural environment.
Each female Pangasius can have 67.000 eggs (taken a parent fish of around 7kg weight). The Pangasius strains used for farming have been developed out of existing wildstock. Today, the fish is fully incorporated in the farming process. Choosing the Parent Fish is most essential to ensure healthy juveniles afterwards. Strong fishes from good strains should be from 3-4 kg and namely 3 years old.
Then the sperm is stripped on top and is mixed mostly using a dry and clean chicken feather. After being stirred from 20-30 seconds, the eggs will be activated and inseminated. And at the end of the process, they will use tannin liquid or the juice of pineapple to separate the fertilized egg from the surrounding tissue.
The procedure of incubation will be in the cement tank for the eggs being separated. The density is about 20,000 to 30,000 eggs per liter for Pangasius hypophthalmus and about 500 eggs per liters for Pangasius bocourti. The size of the fish after 20 days will be around 3cm for Pangasius hypophthalmus. Before transporting to the farm sites, the juveniles are put into water managed by tanks and nylon packs with oxygen. The juveniles are ready to place into the farms at 3 centimeter and they cost the farmer around 1.300 Vietnamese Dong (around 10 US Dollar Cents) per fish.
Care and Feeding
Since they are omnivorous, the Pangasius Catfish or Iridescent Shark Catfish will generally eat all kinds of live, fresh, and flake foods. To keep a good balance, give them a high quality flake food or pellet everyday. Feed brine shrimp (either live or frozen) or blood worms. As they get older they lose their teeth, and like the Pacus, become more and more vegetarian. Keep in mind that the use of Insecticides, antibiotics, waste water and leftover food discharge to pond and other illegal chemicals will prevent progress.
Pangasius can be cultured in fishponds, concrete fish tanks, fish cages and fish pens with the acceptable water conditions: Hardness of 2-200 dGH; Ph of 6.5 to 7.5, temperature of 72-79 °F (22-26 °C) and at least 4-5mg/l of dissolved oxygen in the pond from naturally producing oxygen from phytoplantons or mechanical aerator.
Rearing in Earthen Ponds
The pond should be roughly 1,600 square meters or at least 400 square meters. Growth of the Pangasius hypophthalmus is fast, which is why the appropriate depth is approximately 1.5 – 2 meters. The pond should be situated near a water source in order to fetch in and extract water. Pond preparation is the same as general preparation for other fish ponds. Water to be used in the pond must have a fitting pH value and a proper oxygen concentration. Fingerlings to be used should be selected based on the healthiness of the fish—without wounds, no abnormalities and no disease and approximately all same size to keep them away from fighting for food. Pellet feeds are advisable for feeding to ensure faster growth.
Stocking rate is about 10-15 fish per square-meter. Foods for feeding include pellets, trash fish, water plants and small animals such as insects and worms. Given the proper feeding and management, it can grow to 1 – 1.5 kilo in 5 – 6 months time. Catching the Pangasius can be conducted using suitable net.
Rearing in Floating Cages
Location of floating cages should be near flowing water like rivers, dams and lakes. Size of cages should be 10×10 meters by 5 meter depth. Stocking rate is about 30-50 fish per cubic meter. Food for feeding are pellets, trash fish including water plants and small animals such as insects and worms. Harvest is much easier in cages compared to earthen pond. Nets that are unknotted are advisable to lessen the spones being tangled that can damage the fish.
The Pangasius, same as all other fishes can get diseases such Ichthoyophthirius species parasite, the Trichodina species parasite, inflammation of stomach disease, diseases from the Dactylogyrus species parasite or flat-body parasite and the rice-shape wart disease. This is why it’s important to have traceability of the production (from processing plant to farm hatchery and feed mill) and an appropriate culturing environment (double check site selection and production practices, as well as sanitation).
It was during the first four months of 2006 that progress in farmed Pangasius production in Vietnam along with buoyant international whitefish demand took a significant increase in export volumes. Compared to January-April 2005, Vietnamese volume exports of Pangasius jumped by over 150% to 83,000 tones while the value of exports raised by 140% to $200 million, according to Vietnamese trade figures. 2005 in total amounted to 141,000 tones in export worth $328 million.
The increases during the past year mark acceleration in the upward trend in Vietnamese exports which has been obvious over the past five years. They are also a confirmation of the mounting role of Pangasius products in international whitefish markets, which is reflected in increasing penetration among European retail chains.
In line with an expanding production area devoted to Pangasius farming, Vietnamese output has increased strongly over the past ten years. From 40,000 tones in 1997, farmed volumes passed the 200,000 tone mark in 2004. For 2005, volumes are estimated to have increased by a further 47% to 376,000 tones.
Among EU markets, Vietnamese trade figures point to large increases in sales to Poland, Spain and the Netherlands this year. At 10,000 tones, Poland was the largest customer within the EU during the first four months of 2006 with Vietnamese exports to this market jumping from less than 1,000 tones during the January-April 2005 period. Sales to Spain doubled over the period to 7,000 tones while volumes to the Netherlands were up from less than 300 tones to over 5,000 tones.
The increase in exports to European markets contrasts with declines in Vietnamese volume sales of Pangasius to China (-22%), and Australia (-7%). These declines were, however, more than balanced by the European increases as well as by increased exports to other Asian markets excluding China. Once considered one of the main markets for Pangasius, the US decline this year confirms the steady downward trend.
Freshwater fish species are expected to be cheaper substitutes for white fish which are preferred by many EU customers but which are increasingly expensive due to reduced landings and quota policies. Low price is the main competitive advantage of Pangasius compared with other fish.
According to Eurostat, Germany imported 4,403 tonnes of frozen fillets of freshwater fish during the first eight months of 2005, an increase of 67% compared to the same period of 2004. Vietnam has now overtaken Russia to become the biggest supplier of frozen freshwater fillets to Germany with a share of 37% this year. The strong performance of Vietnam appears to have been helped by a low price level. The unit price for Vietnamese products, at 2.16/kg, was much lower than the overall average unit price of 3-55/kg and lower than the average unit prices for other key suppliers such as the Netherlands (4.90/kg) and Russia (4.40/kg).
In Italy, Vietnam has also achieved a good growth rate this year, with Italian imports of frozen freshwater fillets from Vietnam up 122% for the first eight months of 2005. The 45% Vietnamese share of Italian imports in this category this year compares with 32% during the same period last year. The average unit price of Vietnamese product (2.20/kg) is somewhat lower than the overall category average of 2.50/kg, a differential which may help explain the Vietnamese volume increase.
In Spain, the average import unit price for Vietnamese frozen fillets, at 2.37/kg, is also lower than the overall average of 2.58/kg. The average unit price for Vietnamese product is down 7% this year while unit prices for competing products have been increasing. The Vietnamese share of Spanish volume imports remains strong at almost 70%, an increase on the 65% share during the first nine months of 2004.
In line with the positive import trends in other EU markets, Belgian imports of frozen freshwater fish fillets increased by 36% during the first nine months of 2005 compared to the same period of 2004. With imports from Vietnam up by 65%, the Vietnamese share of Belgian imports increased from 20% of 2004 to 24% of 2005, confirming its number one supplier position.
The viewpoint for additional increase potential for Pangasius products appears optimistic.
Consumer curiosity in balanced protein diets should mean continued buoyancy in whitefish markets. With
comparatively immobile or declining supplies of traditional whitefish species, market awareness in price competitive aquaculture products such as Pangasius should carry on to expand. On the production side, adaptation to a larger scale market situation will remain a key challenge for the industry over the medium term. And ultimately, the future looks bright for Pangasius and those who want to culture it.
Skewers of arugula-wrapped pangasius with shrimp broth Nutritional value (110 g raw)
- Calories: 65
- Cholesterol: o mg
- Lipides: 500 g
- Sodium: 330 mg
- Saturated fat: o mg
- Proteins: 14 g
- Look for flesh that is firm, moist and has a pleasant fresh smell. Full fillet is about 3 pounds. 6 to 8 oz per serving.
- Wrap well in plastic wrap or place in a covered container.
- Refrigerate for up to 3 days or you can freeze for up to 3 months providing your freezer operates at -18°C.
- Due to its low water content, it is recommended that you marinate for 15 minutes in court bouillon with your favorite spices before baking, broiling or barbecuing.
- Its pink boneless flesh has a delicate flavor and fine texture.
- Dip the fish fillets in beaten egg, then in bread crumbs. Season.
- Fry in oil until golden for about 3 minutes on each side until crispy. Serve with pesto potatoes.
author: Hans Audrice B. Estalbo, Marid Digest, photo from diytrade.com