Effect of vermicomposting fertilizer and other organic fertilizers on plankton abundance, growth indices, and survival of Caspian kutum (Rutilis kutum) fry

In this study, the effect of vermicompost fertilizer and other organic fertilizers on plankton abundance, growth indices and survival of Caspian kutum fry was studied. For this purpose, Caspian Kutum fry with an initial weight of 0.15 ± 0.01 g (mean ± standard deviation) were obtained from the Shahid Rajaee fish hatchery center (Sari, Mazandaran) and transferred to a fish farm. Fish were acclimatized to the experimental conditions for two weeks. After acclimation, these fish were divided into 7 experimental treatments: control treatment (C) : no fertilizer, treatment 1 (T1): vermicompost 10 ton / hectare (1 kg / m³), treatment 2 (T2): vermicompost 15 ton / hectare (1.5 kg / m³), treatment 3 (T3): 10 ton compost / hectare (1 kg / m³), treatment 4 (T4): compost 15 ton / hectare (1.5 kg / m3), treatment 5 (T5): cow manure 10 ton / hectare (1 kg / m³), treatment 6 (T6): poultry manure 5 ton / hectare (0.5 kg / m³). The fish, with a mean weight of 0.15 ± 0.01 g, were reared for 60 days in fiberglass tanks. The results showed that application of organic fertilizers had a significant effect on growth indices. The best growth and survival performance was observed in the treatment of vermicomposting 10 ton/ha and poultry manure. Plankton populations were affected by the amount and types of organic fertilizers and the highest phytoplanktonic and zooplanktonic populations were observed in vermicomposting 10 ton/ha and poultry manure treatments. These results suggested that 10 tons per hectare of vermicompost has positive effect on growth parameters and plankton water population in fish breeding of Caspian kutum.