Effect of water hyacinth compost on pond productivity and gut content of rohu (Labeo rohita), fry

The present study was conducted to evaluate the effect of water hyacinth compost on pond productivity and gut content of rohu (Labeo rohita), fry. The experiment was conducted on L. rohita fry in FRP tanks (1.5x1.0x0.75 m), consisted of 5 treatments (T1, T2, T3, T4 and T5) with 3 replicates each. T1 (control) with 10,000 kg/ha cow dung manure (CDM) and four other treatments (T2 to T5) were prepared by incorporating water hyacinth compost (WHC) @ 2500 kg/haWHC+7500kg/ha cow dung manure (CDM), 5000 kg/ha WHC+5000kg/ha CDM, 7500kg/ha WHC+2500kg/ha CDM and 10,000 kg/ha WHC respectively, for 150 days. Fishes were not given any supplementary feed during the study period. WHC alone (T5) did not affect pond productivity significantly (P≤0.05), however significantly (P≤0.05) higher chlorophyceae, cyanophyceae, bacillariophyceae, euglenophyceae and total phytoplankton and copepoda, rotifera, cladocera, protozoa, ostracoda and total zooplankton population were observed in T4 treatment as compare to control (T1). Whereas, gut content analysis revealed significantly high (P≤0.05) detritus content (56.20) in T1 and low (29.25) in T4 treatment, unidentified matter was recorded maximum (16.77) in T2 and minimum (11.31) in T4 treatment. Results revealed that water hyacinth compost improved pond productivity and recorded highest in T4 (CDM 25% + WHC 75%) which also confirmed through the gut content analysis. In developing countries like India, fish farmers are unable to buy costly fish feed and chemical fertilizers, water hyacinth compost form an abundant alternative natural un-utilized resource for less expensive manure to improve pond productivity.