Seed production practices of striped catfish, Pangasianodon hypophthalmus in the Mekong Delta region, Vietnam

Hatchlings to fry, and fry to fingerling rearing of the striped catfish (Pangasianodon hypophthalmus) sectors of the Mekong Delta (8°33’- 10°55'N; 104°30’-106°50'E), Vietnam, a practice that has witnessed an explosive growth (1,094,879 tonnes, in 2008), in an area of approximately 7,000 ha, and the produce exported to over 100 countries, is presented. The findings are based on a survey of 45 hatcheries and 47 nursery farms located in three provinces (Dong Thap, An Giang and Can Tho) where these activities are predominant. Hatchery and nursery farm size ranged from 0.2-15 ha (2.5 ± 0.5 ha), with 0.05-10 ha (1.59 ± 0.3 ha), and from 0.09-11 ha (mean 1.9 ± 0.4 ha), with 0.01-8 ha (1.36 ± 0.28 ha) under water, respectively. Hatcheries maintained 350 to 29,200 (8,042 ± 805) fish, of which 240-11,300 (4,100 ± 454) are considered as broodstock, the rest being potential broodstock. The mean weight of male and female broodstock ranged from 0.5-8 kg and 0.5-12 kg, respectively, maintained at a ratio of 0.05-1.0 (mean 0.34 ± 0.03). Fish spawned were at least 1.75 kg (female) and 1.5 kg (males), and induced spawned by injection with HCG. Females received four or five doses at a time (averages 542, 597, 893 and 3,442 IU/kg or 500, 500, 500, 1500 and 3000 IU/kg; injected at 0, 23, 46, 56 and 66 hrs). Ovulation occurred 5-11 hours after the last injection (at 28-29 °C). The relationship of relative fecundity and larvae per kg to body weight are:Eggs/ kg (mil.) = 0.151 - 0.015 x female wt (kg) (P = 0.006, Adj. R2 = 0.179)Larvae/ kg (mil.) = 0.108 - 0.012 x female wt (kg) (P = 0.006, Adj. R2 = 0.182)