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This study was conducted to evaluate the effect of commercial probiotic including bacillus spores (5 species) on the bioremediation of the effluent of cultivation system of common carp fingerlings (Cyprinus carpio). This experiment was conducted in two treatments: Probiotic treatment (T1), the blend of bacilli which were added to the waste water of tanks at a concentration of 1×108 CFU/liter and control treatment which no bacilli were added. At the starting of the experiment and after inoculating of bacteria into the waste water, the water quality parameters, such as Total Ammonia Nitrogen, NO2-N, NO3-N, EC, TDS and turbidity were measured at the intervals of 24, 48 and 72 h. The employment of these bacterial bioremediator in the waste water of rearing system of common carp resulted in significantly lower concentrations of TAN. Also, turbidity and total count of bacteria significantly decreased after 48h and NO3-N significantly decreased after 72h (P<0.05). In another trial, the inoculated waste water with concentration of 1×108 CFU/liter and effluent water obtained from rearing tanks of carp were used for rearing system of common carp fry, respectively. After 45days the reared fish in treated water had higher final body weight, SGR, ADG%, and lower FCR in comparison with reared fish in untreated waste water.

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The purpose of this study was to assess the effluents from a rainbow trout (O. mykiss) farm located in Golestan Province, and their impact on the water quality. Water samples were taken from input and output waters of farm every 20 days during four months. Water quality analysis results showed that rainbow trout farm had a significant impact on temperature, pH, TSS, Dissolved Oxygen (DO), No2, No3, and NH3 concentrations. The amount of dissolved oxygen (DO) in the effluent water of farm decreased compared to the water input significantly, while the values of pH, TSS, NO2, NO3, NH3, increased. According to the results of this study, the water quality and physicochemical factors are influenced by the effluent from rainbow trout farm due to the changes in the environmental conditions and the farm activities. 

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Growth, hematological parameters and water quality for great sturgeon (Huso huso), were determined at three different stocking densities and three feeding rates. Stocking density were 1, 1.5 and 2 kg m-2 and feeding rates were 1, 2, and 3% body weight day-1. Sturgeon were offered to 18 tanks and 3×3 experimental design was used with two replicates per treatment. Initial average body weights of the fish were 25 ± 1.5g and were hand-fed a pelleted commercial feed (44 % protein, 20% fat, and 7% ash) twice daily throughout the experiment period. After about 7 weeks of feeding, optimal feeding rate and growth performance was observed in 1 kg m-2 and 3% of body weight day-1 and there were significant difference interaction in stocking density and feeding rate between treatments (P<0.05). The results demonstrated that hematological parameters were not significantly different in all groups (P>0.05). No mortality was abserved during the experiment. Water quality including ammonia (NH3) and dissolved oxygen (DO) showed significant differences (P<0.05) among the treatments affected by different densites and feeding rates, while temperature and pH showed no significant difference (P>0.05). Results show that the optimum feeding rate and stocking density for fishes weighing 25 to 155 would appear at a feeding rate at 3% body weight day-1 with the stocking density 1 kg m-2.

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The current research was conducted in 2021 in 5 stations in order to investigate the quality of water before the operation of Javeh Dam in Kurdistan Province. Sampling of fish and Macrobenthos was done using an electrofishing device and Surber sampler, respectively. A total of 13 fish species were identified, which belonged to 3 families: Cyprinidae, Mastacembelidae and Nemachielidae. Out of the total of 2003 fish caught in all the stations, more than 96.6% belonged to the Cyprinidae family. The highest relative frequency of 32.4% belonged to Capoeta damascina species. In addition, 2 exotic species, Carrasius auratus and Carrasius gibelio had an abundance percentage of 1.4. The diversity of fish species decreased from station 1 (upstream) to stations 2 and 3, which was probably influenced by human activities such as various types of pollution, but in station 5 of It had the maximum amount, which is due to the change in habitat conditions, such as the increase in flow rate and water depth. The results showed that the species diversity of fish had changes in different seasons, so that its minimum was estimated at 0.91 in winter and its maximum at 1.29 in summer. Macrobenthos included 10 families Chironomidae, Lumbriculidae, Simulidae, Baetidae, Hydropsychidae, Erpobdelidae, Glosiphonidae, Gamphidae, :union:idae and Potamidae. The classification of water quality based on the Karr ecological integrity showed that stations 1 and 4 were placed in the good quality class with a numerical value of 40 and 42, respectively, and stations 3 and 5 were placed in the very low and medium water quality classes with a numerical value of 9 and 34, respectively. In this way, it is necessary to manage and organize all sources of point and non-point pollutants in Gheshlagh and Gavehroud tributaries.