Performance of hatchery-produced and feed-weaned fingerlings of striped murrel Channa striata (Bloch, 1793) in biofloc system in the subtropical climate

The performance of hatchery-produced and pellet-feed-weaned fingerlings of striped murrel, Channa striata (Bloch, 1793) was assessed in the biofloc tanks for growth and survival, in a subtropical climate. The rearing was undertaken in two phases with an increase in fish size. In the first phase, fingerlings (weight 1.94±0.71 g, length 6.29±0.81 cm) were stocked @ 200 m-3 in the biofloc tanks, which were reduced to 15 m-3 in the second phase using the same stock. The fish attained a length of 25.44±1.81 cm and weight of 149.60±28.58 g in 10 months with overall survival of 93% at the end of the second phase. The total fish biomass recorded was 9.7 kg m-3 at the final harvest. The growth parameters were found temperature-dependent, which recorded 15±1.0 to 28±1.5ºC and 'W' values were found to follow Fulton's cube law during the entire culture period. The exponent (b) of 3.278 was recorded as the highest in July 2020 and lowest at 2.210 in December 2020. The lowest R2 was 0.768 and highest 0.943 during December and April respectively whereas, the recorded ‘K’ of 0.611 was the lowest in winter and highest being 0.908 in August. The study demonstrated a higher culture potential of striped murrel with hatchery-produced and feed-weaned seed in the biofloc system with zero-water exchange. Keywords: Condition factor, Fulton's cube law, Growth, Production, Survival, Zero-water exchange