SUSTAINABLE SNAKEHEAD AQUACULTURE DEVELOPMENT IN THE LOWER MEKONG BASIN OF CAMBODIA

Farming snakehead is prohibited in Cambodia due to its dependence on freshwater small-sized fish (FSF) for sourcing key dietary nutrient inputs and seed collected from the wild, while lack of technologies on developing of snakehead hatcheries through breeding, weaning and grow-out on formulated or pelleted diets.  This study was conducted to investigate weaning and grow-out performance of the wild indigenous Channa striata (non-domesticated) in Cambodia compared to those of domesticated snakehead imported from Vietnamese hatcheries on formulated or pelleted feed (FF or PF) and to assess economic efficiency and product quality of the two types of snakehead fed on different diets at the end of experimental grow-out. In the experiment 1 (weaning): 3 day-old larvae of both types of both C. striata were stocked in 50 L-tank at a density of 5 fish L-1 and fed on Moina, FSF and FF (45% CP) to satiation four times daily for 45 days. In experiment 2 (grow-out): the experiment was conducted in 18 hapa-nets (1.8m x 2.5 m x 1.8 m) placed in 3 earthen ponds (300 m2 each) at a density of 100 fingerlings hapa-1 (3 replicated hapas for domesticated fingerling and 3 replicated for non-domesticated). Snakehead fingerlings (12-13 g fish-1) were fed on three diets: 1) FSF (Pond 1); 2) PF (40% CP, Pond 2); and 3) 50:50 mixtures of FSF and PF (Mix, Pond 3). The fish was fed to satiation twice daily for 6 months. The results of the study showed that weaning of non-domesticated and domesticated C. striata larvae on FF can start at 17 days after hatch with replacement ratio 10% FF day-1 for substituting FSF. Feed intake (107 mg fish-1 day-1) and final weight (170 mg) of domesticated snakehead was higher than the ones (85 mg fish-1 day-1 and 146 mg, respectively) of non-domesticated snakehead, while survival rate (29%) and Cannibalistic rate (47%) of the domesticated was lower than the ones (36% and 51%, respectively) of the non-domesticated. In grow-out experiment, both snakeheads can accept formulated or pelleted feed. However, the domesticated snakehead showed higher survival rate (75%), better growth performance (final body weight 367 g fish-1), higher feed intake (3 g fish-1 day-1) and food conversion ratio (FCR; 1.5) than the non-domesticated snakehead (69% and 233 g fish-1, 2 g fish-1 day-1 and 1.7, respectively) since the domesticated hatchery snakehead has been gone through more than two-decade domestication. Considering economic efficiency, replacing freshwater small-sized fish by pelleted feed up to 100% is possible and profitable for both snakeheads. However, the domesticated snakehead (about US$ 0.35/kg fish produced) showed higher profit than the non-domesticated snakehead (US$ 0.25/kg fish produced). In regards to product quality, pelleted feed does not significantly affect the fillet quality of both cultured snakeheads compared to a diet of FSF and a mixture.