Success Stories In Asian Aquaculture - Library - Network of ...

132 N.T. Phuong and D.T.H. Oanhproduction and culture techniques; (2) establishment and expansion of exportmarkets; (3) development of feed and processing infrastructure;, and (4) supportivepolicies the government. It is expected that this sector will continue to grow further,albeit at a reduced rate, and will be sustainable.7.1 Why is it Striped/Tra Catfish ( Pangasianodonhypophthalmus )?The Mekong delta in the southern part of Vietnam is known as the region forcatfish farming (Plate 7.1 ). Catfishes in Vietnam comprise two genera,Pangasius with ten species and the single species genus Pangasianodon . Thesespecies also occur in Cambodia, Laos, and Thailand ( www.fishbase.org ). Ofthese, Pangasius bocourti and Pangasianodon hypophthalmus have beenfarmed in the Mekong delta for decades. The former has been commerciallyfarmed in cages since the beginning of the 1960s, and reached its peak productionin 1994 (Phuong 1998) . In the early phases of the culture of the catfishspecies, the seed stock was caught from Cambodian and Vietnamese waters,particularly in the confluence region of the Mekong, Bassac, and Tonle Saprivers. The second species has been traditionally farmed in small ponds usingwild seed for few decades, and commercial culture in cages, pens, and pondscommenced with the development of artificial mass seed production in 2000(Tuan et al. 2003) . These fishes were very common and served as a daily foodfor many Vietnamese people who live in the southern part of Vietnam, especiallyin the Mekong Delta.7.2 Striped Catfish: Life CycleStriped catfish ( P. hypophthalmus ) is a migratory species. The fish moves upstreamof the Mekong River at the end of flooding season (from October toFebruary) and returns to the main stream at the beginning of the rainy season(from June to August). The spawning ground of striped catfish is generallyknown to be in the upstream of the Mekong River Delta, more especially, belowthe Khone Falls on the Lao-Cambodia border (MRC 2002 cited by Trong et al.2002 ). The fish spawns at the beginning of the rainy season and the adhesive eggsare deposited on roots of aquatic macrophytes and other types of substrates. Thenewly hatched larvae drift downstream with the water current and swept intofloodplain areas in southern part of Cambodia and the Mekong delta in Vietnam.Striped catfish is an air-breathing species (Browman and Kramer 1985 cited byCacot 1999) , which allows the fish to withstand low levels of dissolved oxygen.However, this fish prefers deep and flowing water, and therefore, farming areas ofstriped catfish are mostly along the branches of Mekong River banks and largecanals (Fig. 7.1 ).