PREY SPECIES AND SIZE SELECTION OF ODONTOBUTIS POTAMOPHILA

Odontobutis potamophila Günther is a carnivorous and high-priced fish species. Shrimp is the prey of O. potamophila which has high cost, so, prey fish with lower price may be more suitable for O. potamophila culture. In this study, we verified the prey selection of O. potamophila during different growth stages using eight prey species, and identifid prey species of a suitable size for O. potamophila culture in three different sizes. The results showed that O. potamophila had a strong selectivity for Cirrhinus mrigala Hamilton, with the preference index which was significantly higher than that of the seven other prey species. O. potamophila also exhibited strong selectivity for small-sized individuals, such as Squaliobarbus curriculus Richardson. Significantly positive linear relationship was observed between the total length of O. potamophila and C. mrigala. Prey-to-predator size ratio (PPR) for C. mrigala consumed by O. potamophila ranged from 0.23 to 0.73 (0.49±0.1: mean±SD). With the increase in O. potamophila sizes, PPR for C. mrigala consumed by O. potamophila decreased. Moreover, O. potamophila fed relatively smaller C. mrigala during different growth stages. Overall, the results indicated that C. mrigala with PPR of 0.38—0.6 could be used as a prey for O. potamophila culture.