Essay: Vietnam Catfish Operations Manual



Vietnam Catfish Operations Manual

https://www.fishbase.de/summary/Pangasianodon-hypophthalmus.html

Photo by: Mahalder, B.

Classification:

Actinopterygii (ray-finned fishes) → Siluriformes (catfish) → Pangasiidae (shark catfish)

Scientific name: Pangasius hypohthlamus

Common name: Tra catfish, swai, Vietnam catfish

General Biology/Ecology

“Pangasius catfish are a freshwater fish that natively live in a tropical climate. They prefer a large body of water with shallow depth.” (Coker) They are also benthopelagic and potamodromous fish.” ( Vidthayanon, 2011)

“Van Zalinge (2002) suggests size at first reproduction to be approximately at 3.5 kg or 60 cm. Khanh (1996) and Xuan (1994) published similar estimates of approximately 112,000 to 138,000 eggs per kilogram body weight after age four. River catfish reach full maturity after age ten. Absolute maximum fecundity is 2,000,000 (Khanh 1996). Mortality rates are difficult to estimate, because of the complicated life history of the river catfish. Many factors, including reproductive ecology, small egg size, and high fecundity suggest that the species is adapted to high mortality of early life stages.” ( Vidthayanon, 2011)

Maturity length, weight, and age:

“Adult Pangasius can reach up to 3 metres in length and weigh up to a maximum of 44kg. The table size can weigh up to 2kg in 6 months.” (Coker)

• Max length: 130 cm SL male/unsexed

• Max weight: 44 kg

• Maturity age: between 2-4 years; 10-15 is the best estimate of generation length

Generation length (years): 10-15

Water Quality

• pH range from 6.5-7.5

• dH range: 2-29

• Dissolved oxygen can range between 0.5-0.10 mg/litre

• Temperature can range between 22-26 degrees Celsius

• “The fish is very robust. Known next to no disease. Need no high Oxygen level in water unlike Tilapia.” (Coker)

“Being a facultative air breather P. hypophthalmus tolerates highly polluted water (chemical oxygen demand = 25) and can be stocked at densities as high as 120/m2.” (FAO, 2018)

Natural Distribution

¬ Current distribution

• Asia in the Mekong River and Chao Phraya basins. “The Mekong River Basin is probably the largest and most important inland fisheries in the world. The annual yield from capture fisheries in the lower Mekong basin (encompassing the Lao People’s Democratic Republic, Thailand, Cambodia and Viet Nam) is estimated at between 2.5 to 3 million tonnes, accounting for 2 percent of the total annual global fisheries yield including both marine and inland fisheries. This in turn represents a direct monetary value of approximately US$2 000 million annually.” (Barlow, 2006)

¬ Introduced to Indonesia, Malaysia, and Myanmar.

Main producer countries of Pangasius hypophthalmus (FAO Fishery Statistics, 2006)

General morphology

External: Elongated body, present adipose fin, forked caudal fin, scaleless, about 8-9 soft rays in the pelvic fin. “Fins dark grey or black; 6 branched dorsal-fin rays; gill rakers normally developed; young with a black stripe along lateral line and a second long black stripe below lateral line, large adults uniformly grey (Ref. 12693). Dark stripe on the middle of anal fin; dark stripe in each caudal lobe; small gill rakers regularly interspersed with larger ones (Ref. 43281).” (Fishbase, 2017)

Characteristics of this species:

(Peñafiel, 2013)

What is it good for? “Fisheries: commercial; aquaculture: commercial; aquarium: public aquariums.” (Fishbase,1878)

Trends: “It is anticipated that aquaculture production of Pangasius hypophthalmus will further increase in the medium term. Prices will initially remain stable, but may drop later if China solves its striped catfish production problems and increases output. “ (FAO, 2018)

“However, the farming of this species is a very high risk activity for household-scale production units because profit margins are extremely tight. It is likely in the medium- to long-term that household-scale grow-out producers will go out of business as the industry consolidates. Associated with increasingly strict market requirements for tracking, tracing and product certification, striped catfish farming will probably move toward large-scale vertically integrated operations.” (FAO, 2018)

Obtaining Stock

 “Wild-caught sources of this species were once an important food fish in Thailand, Lao PDR, Cambodia, and Vietnam. Roberts (1993) notes the disappearance of wild adults from Thailand during the 1980s and early 1990s. Adult individuals are still present in the Chao Phraya in small protected areas near temples, but the population status outside these protected areas is unclear (Z. Hogan pers. comm. 2011). Vidthayanon (pers. comm. 2011) states that, in the Chao Phraya River basin, the species now only exists as escapee or semi-captive populations. The species has also been extirpated from the Mekong in Thailand due to overfishing of adults.” (C. Vidthayanon pers. comm. 2011)

Local or import?

“Pangasius hypophthalmus fries were imported into Nigeria two and the half years ago, under license from the Federal Ministry of Agriculture, as a consequence of the felt needs to diversify Nigeria’s aquaculture breeds, and to ensure such breeds like Pangasius which are not carnivorous; are disease-free; can thrive on 100% plant foods especially rice bran and soya bean cakes.” (Coker)

Broodstock Management

Seed Supply:

“In the Mekong delta of Viet Nam the capture of wild Pangasius hypophthalmus seed for aquaculture stocking has been entirely replaced by the stocking of hatchery-produced seed. However, operations in Cambodia, Lao People's Democratic Republic and, to a lesser extent, Thailand still use wild-captured juveniles as seed for cage and pond culture.” (FAO, 2018)

“Mature broodstock P. hypophthalmus are induced to spawn in hatcheries using HCG or HCG and pituitary gland extract. Female broodstock are given between 2-4 hormone injections while males are injected only once when the female resolving dose is given. Broodstock are spawned in single pairs or in larger numbers and are usually dry stripped. The eggs are incubated in conical shaped jars made either of stainless steel or glass, with up-welling water flow to keep the eggs in suspension. Depending on water temperature, the eggs hatch usually hatch within 22-24 hours. Yolk sac absorption takes a further 24 hours. The larvae are transferred from the hatchery just prior to full yolk sac absorption.” (FAO, 2018)

Nursery:

“Nursing is done in 2 separate stages to reduce stocking density. Earthen nursery ponds, typically 1 000-5 000 m2, are pre-prepared by drying (1-3 days, depending on season), liming (1 t/ha), filling and stocking with Moina (20-30 kg/ha). Water supplied to nursery ponds is filtered through fine meshed cloth to exclude predators. In the first nursing phase larvae are stocked at 400-500/m2 just prior to yolk sac absorption, so that natural feeds are available and the larvae have enough space to avoid cannibalism. Water is only topped up and is not exchanged during the nursery phase unless water quality deterioration is obviously causing stress. Boiled egg yolk and soybean meal mixed into an emulsion is fed 5 -6 times a day for the first 2 weeks. Thereafter commercial pellets are fed.” (FAO,2018)

“After 4 weeks, following a 24 hour starvation period the nursery ponds are partially (about 1/3 depth) gravity drained and then pumped dry, and the 0.3-1 g fry are harvested by seine net and transferred and stocked at 150-200/m2 in another pre-prepared pond without Moina. Typical larvae to fry survival rate during the first nursing stage is 40-50 per cent. In the second nursing stage, from fry to 14-20 g fingerlings, survival rates over the 2 month nursing period are typically 60-70 per cent.” (FAO,2018)

“In the Mekong delta of Vietnam the majority of fingerlings are transported from nursery facilities to grow-out farms in transport tanks with continuously pumped water that are carried in boats. Fingerling transport is done early in the morning to avoid direct sunlight. Transportation of fingerlings overland is less commonly conducted; this involves using metal drums with car battery powered aeration. Additionally, transportation overland for very short distances can be carried out in metal drums without aeration.” (FAO,2018)

“Wild broodstock typically spawn twice annually but in cages in Viet Nam have been recorded as spawning a second time 6 to 17 weeks after the first spawning.” (FAO, 2018)

Spawning

“Spawning adults migrate upstream each year in at the beginning of the flood season. Eggs are sticky and apparently deposited on submerged vegetation (Van Zalinge et al. 2002) or onto the exposed root systems of rheophilic tree species like Gimenila asiatica. (FAO, 2018). Emerging fry disperse downstream with the rising flood waters.” (Singhanouvong et al. 1996)

Fertilization is external. “They are migrant fish going up the river when ready to spawn and travelling down the river as juveniles. They like warm water and the wet season that last in Mekong delta from March until late October each year.” (Coker)

“A migratory species, moving upstream of the Mekong from unknown rearing areas to spawn in unknown areas in May-July and returning to the mainstream when the river waters fall seeking rearing habitats in September -December (Ref. 37772). South of the Khone Falls, upstream migration occurs from October to February, with peak in November-December. This migration is triggered by receding water and appears to be a dispersal migration following the lateral migration from flooded areas back into the Mekong at the end of the flood season. Downstream migration takes place from May to August from Stung Treng to Kandal in Cambodia and further into the Mekong Delta in Viet Nam. The presence of eggs during March to August from Stung Treng to Kandal indicates that the downstream migration is both a spawning and a trophic migration eventually bringing the fish into floodplain areas in Cambodia and Viet Nam during the flood season (Ref. 37770). Common in the lower Mekong, where the young are collected for rearing in floating fish cages. In the middle Mekong it is represented by large individuals that lose the dark coloration of the juveniles and subadults and become grey without stripe (Ref. 12693).” (Fishbase, 1878)

Larval Rearing

 “Incubation of eggs and Larval Rearing:

• Pangasius eggs hatch within 24-30 hours

• After hatching, yolk sac absorption takes a further 24 hours and the larva begin to feed

• On the third day the fry are transferred to a nursery pond to avail of the natural food present in the pond.” (Peñafiel, 2013)

“Eggs are sticky and apparently deposited on submerged vegetation (Van Zalinge et al. 2002) Emerging fry disperse downstream with the rising flood waters.” (Singhanouvong et al. 1996) (FA0, 2018)

Grow-out

Types of feed: floating feed

Why?

“The fish has not been used before for it was mostly a bottom feeder and could have some problems in taste through this habit but since the development of an industrial produced enhanced floating feed that could be taken by the fish from the top of the water surface also Pangasius hypophthalmus could be used and farmed successfully. They feed mostly from the ground, have no teeth, in the wild they are omnivorous and diet consists of Crustaceans other fish and plant matters.” (Coker)

Feeding

 

Feeding time (Photo: J. Garrison/MRC) Making home-made feed (Photo: SUFA, FSPS)

“Pangasius has a low protein feed content compared to Clarias. It is succulent and palatable. Nowadays, some 98% of the exported Pangasius belongs to the Hypophthalmus species. They do not cannibalize.” (Coker)

“In the 1990’s, most Vietnamese striped catfish on-growing producers used farm-made feeds prepared from various ingredients, including trash fish, rice bran, soybean meal, blood meal, broken rice, cottonseed flour, milk, eggs and vegetables (e.g. water spinach and green peas), supplemented with Vitamin C and E premixes. The ingredients are mixed together, cooked and fed in balls or extruded into noodle strands or pellets.” (FAO, 2018)

“From 2008, with food safety concerns and fluctuating farm-made feed quality, there is now an increasing trend towards the use of commercial pellets. The unit cost of farm-made feeds is cheaper but these feeds have FCRs of 2.8-3.0:1 and cause greater water quality deterioration. The feed conversion ratio of P. hypophthalmus fed commercial pellets is typically 1.7-19:1. Larger-scale producers in Viet Nam only use commercial pellets, while medium-scale grow-out producers typically usually use commercial pellets for the first month and the last month of the ongrowing period and farm-made feeds for the middle four months. This technique reduces the cost of each kilogram of fish produced despite the higher FCRs of farm-made feeds. Depending on rearing intensity feed represents 65-85 percent of on-growing costs.” (FAO, 2018)

Production Planning

Production cycle of Pangasius hypohthlamus

Harvesting

Techniques:

o “Striped catfish are harvested from ponds by netting, following partial tidal gravity drainage and pumping. Cages are harvested by raising the cage netting by hand. It is normal for an entire pond or cage to be harvested at a single time to meet the large volume requirements of processing plants. Net pens are harvested by seine netting on spring low tides. (FAO, 2018)”

Processing

Processing striped catfish fillets for export (Photo: Erik Keus)

“The harvested fish are usually transferred to processing plants live in well boats without aeration by river.” (FAO,2018)

“The majority of striped catfish is exported in freezer containers by sea as frozen fillets (2.7-3.3 kg of fish is required to produce 1 kg of fillet). Live whole fish are sold in the domestic market, being transported either in well boats without aeration or in tanks on trucks with aeration.” (FAO,2018)

Production Costs

“Production costs for household-scale intensive pond-reared P. hypophthalmus are relatively stable but margins are extremely tight. Production costs in early 2009 for commercial-scale striped catfish grow-out producers were approximately VND 15 000/kg (USD 0.83/kg) excluding capital investment costs; this was offset by sale prices of VND 16 000/kg (USD 0.89/kg). At that time household-scale grow-out producers were only being paid VND 14 000-15 000 (USD 0.78 – 0.83/kg) for market sized fish by processing plants but their production costs at approximately VND 13 000 – 14 000 (USD 0.72 – 0.78 kg) excluding capital investment costs were lower . Most grow-out farmers view capital investment costs as a ‘sunk cost’. Profit margins in early 2009 were so tight that striped catfish grow-out farmers in Vietnam were unlikely to recover their capital investment costs fully.” (FAO, 2018)

Use, Market, and Trade

“The species, including eggs and fry. are heavily exploited. Annual harvests have been estimated to be as much as 100,000 to 150,000 tons per year (MRC 1992; Csavas 1994), although culture of pond-stocked fry accounts for the majority of this production (MRC 1992). Until recently, an estimated 200,000,000 to one billion eggs and fry are collected annually from Cambodia and Viet Nam. Juveniles of this species are popular for aquarium trade.” (Vidthayanon, C. & Hogan, Z. 2011) (IUCN, 2011)

“Viet Nam exports P. hypophthalmus to over 80 countries, including several in Europe (especially Poland and Spain), Asian countries, Mexico, Australia, the United States of America, and the Middle East. New markets such as Russia are emerging. The European Union remains the most significant market (35 percent by volume, 40 percent by value).” (FAO, 2018)

“Viet Nam has the capacity to process 3 500 tonnes of aquatic product daily and the capacity is increasing. There are presently 405 industrial-scale processing plants in Viet Nam, of which 301 are certified for export to Europe and 30 are certified to export to the Russian Federation; 16 percent are currently ISO certified.” (FA0, 2018)

“Following low prices at the end of 2008 many Vietnamese farmers failed to stock their ponds in 2009, thus raising market price. The 2009 indicative price of 170 g skinless IQF striped catfish fillets imported into Europe from Viet Nam was USD 2.65/kg.” (FAO, 2018)

“The farming of Pangasius hypophthalmus has seen it emerge as a commercial freshwater species that is now a significant component of global whitefish supplies. While trade in frozen products generally stagnated in 2007 and 2008, P. hypophthalmus was the exception, with trade increasing 311 percent, traded primarily as frozen IQF fillets. This species is now a highly competitive, high value white fish product on many markets.” (FAO, 2018)

Status

“However, the farming of this species is a very high risk activity for household-scale production units because profit margins are extremely tight. It is likely in the medium- to long-term that household-scale grow-out producers will go out of business as the industry consolidates. Associated with increasingly strict market requirements for tracking, tracing and product certification, striped catfish farming will probably move toward large-scale vertically integrated operations.” (FAO, 2018)

Works Cited

Coker, Muyiwa, and Kayode Oni. “PANGASIUS HYPOPHTHALMUS.” SlidePlayer, slideplayer.com/slide/4482067/.

“FAO Fisheries & Aquaculture Pangasius Hypophthalmus.” Fao.org, FAO of the UN, 14 Jan. 2010, www.fao.org/fishery/culturedspecies/Pangasius_hypophthalmus/en.

Hogan, Z, Baird, I.G., Radtke, R. and Vander Zanden, J. 2007. Long distance migration and marine habitation in the Asian catfish Pangasius krempfi. Journal of Fish Biology 71: 818-832.

Pasculita, Sa-a. “Pangasius Bocourti Summary Page.” FishBase, www.fishbase.de/summary/Pangasius-bocourti.html.

Peñafiel, Rodney. “Hatchery Technology of Pangasius.” LinkedIn SlideShare, 12 Oct. 2013, www.slideshare.net/jhong2x/hatchery-technology-of-pangasius.

Poulsen, Anders, et al. “Part 2 Species Paper.” Capture-Based Aquaculture of Pangasiid Catfishes and Snakeheads in the Mekong River Basin. www.fao.org/tempref/docrep/fao/011/i0254e/i0254e02.pdf.

Rainboth, Walter J. “Fishes of the Cambodian Mekong.” Google Books, Food and Agriculture Organization of the United Nations, books.google.com/books?id=sZQbV75rtAQC&pg=PA255&dq=Pangasius%2Bpangasius&hl=en&sa=X&ved=0ahUKEwi1_6qZjdTaAhXnq1QKHTTsAQIQ6AEIQTAF#v=onepage&q=Pangasius%20pangasius&f=false.

Roberts, T.R. 1993. Artisanal fisheries and fish ecology below the great waterfalls of the Mekong River in southern Laos. Siam Society – Natural History Bulletin 41: 31-62.

Roberts, T.R. 1993. Artisanal fisheries and fish ecology below the great waterfalls of the Mekong River in southern Laos. The Natural History Bulletin of the Siam Society 41: 31-62.

Singhanouvong, D., Soulignavong, C., Vonghachak, K., Saadsy, B. and Warren, T.J. 1996. The main wet-season migration through Hoo Som Yai, a steep-gradient channel at the great fault line on the Mekong River, Champassack Province, Southern Lao PDR. Indigenous Fishery Development Project, Fisheries Ecology Technical Report No. 4.. Technical Section, Dept. of Livestock-Fisheries, Ministry of Agriculture-Forestry, Lao People's Democratic Republic.

Van Zalinge N., Sopha, L., Peng Bun, N., Kong, H., and Valbo-Jorgensen, J. 2002. Status of the Mekong Pangasianodon hypophthalamus resources, with special reference to the stock shared between Cambodia and Viet Nam. Mekong River Commission, Phnom Penh.

Vidthayanon, C. & Hogan, Z. 2011. Pangasianodon hypophthalmus. The IUCN Red List of Threatened Species 2011: e.T180689A7649971. http://dx.doi.org/10.2305/IUCN.UK.2011-1.RLTS.T180689A7649971.en.