Effects of salinity on selected reproductive physiological parameters of striped snakehead (Channa striata)

Abstract

This study aimed to investigate the effect of salinity on reproductive physiological parameters of striped snakehead (Channa striata). Striped snakehead with the body weight of 400 grams were cultured in three salinities including 0‰ (control), 3‰ and 6‰ with three replicates. A recirculating culture system was used for each treatment, which consisted of two 500L-biofilter tanks and three 1m3 rearing tanks. Thirty fish were stocked in each tank. After 4 months of culture, the growth of fish was highest in the control treatment (279±165 g/fish) and the lowest was at 6‰ treatment (196±142 g/fish). Physiological parameters such as haemoglobin, haematocrit were significantly higher in 6‰ treatment if compared to 3‰ and control treatments. Red blood cells ranged between 3.07±0.3x106 and 3.44±0.3x106 cells/mm3, while the highest of white blood cells was at 6‰ (116.7±39.3x106) which was significantly higher than in the control (62.9±16.9x106). Osmolality and Cl- ion concentrations in 6‰ treatment (301±5.5 mOsm/kg and 104±3.86 mM, respectively) were higher than that of 3‰ treatment (294±6.20 mOsm/kg and 99.9±3.23 mM) and the control treatment (287±6.9 mOsm/kg and 95±5.31 mM). The results also showed that the highest of gonadosomatic index of female (5.8±2.62%) was in the 3‰ treatment, while the lowest (3.85±1.95%) was in the control. The vitelline concentration was highest in the 6 ‰ treatment, and lowest in the control. The absolute fecundity and the relative fecundity were highest at 3‰ treatment and the lowest were in 6‰ for absolute fecundity and in the control for relative fecundity.