Effect of using different types of organic animal manure on plankton abundance, growth performance and survival of Carps fry in fiberglass tanks

In this research, the effect of organic fertilizers was studied on the growth performance of carps fry. This experiment was conducted in a completely randomized design with seven treatments and three replications in 300 liters of tanks within 3 months. 60 pieces of fish fry with an average weight of 0.6 ± 0.05 g were randomly storage in each tank per 0.5: 1.5: 2: 6 (respectively, 5%, 15%, 20% and 60% respectively big head, grass carp, common carp, silver carp). Seven treatments were included control (C), vermicompost of 1 kg/m3 (T1), vermicompost fertilizer  1.5 kg/m3  (T2), compost fertilizer 1 kg/m3  (T3), compost fertilizer 1.5 kg/m3 (T4), cow manure 1 kg/m3  (T5), chicken manure 0.6 kg/m3 (T6) used in 3 replicates. Primary production, plankton and water quality parameters (temperature, chemical oxygen demand, dissolved oxygen, nitrogen-ammonium and phosphate) were measured weekly or twice weekly. At the end of the experiment period, the growth indices were measured. The results showed that the highest amount of dissolved oxygen, chlorophyll a concentration, phytoplankton and zooplankton was observed in T1 treatment and the lowest in control group (p<0.05). The highest amount of benthos was observed in T6 treatment compared to other group. Based on the results, the best growth performance was observed in T1 treatment, except to T6 treatment with other treatments (p<0.05). Overall, the results of this study suggest that vermicompost application of 1 kg/m3  can improve the quality parameters of water, plankton and performance of Carps fry.