Hydrology, hydrobiology and environmental pollution in the southern of Caspian Sea

The phytoplankton, zooplankton, Macrobenthos and ctenophore Mnemiopsis leidyi with Physico-chemical parameters and pollutants of water were investigated in the Caspian Sea during 2007-2008. The sample station located between 48° to 54° longitude and 36° to 39° latitude. The samples were gathered in four seasons and eight transects (half-line perpendicular to the coast) in Astara, Anzali, Sefidrud, Tonekabon, Noshahr, Babolsar, Amirabad and Turkmen. Sampling was done of 5, 10, 20, 50 and 100M depth of different layers. Nonparametric test and multivariate analysis (PCA) were used for statistical methods. Physico-chemical factors: The results showed that the changes of physico-chemical factors, includes: water temperature, salinity, organic nitrogen and inorganic nitrogen (ammonium) are most important than other factors. The lowest sea surface water temperature was recorded in winter (7.2°C) and highest in summer (29.8 °C) (p0.05). The lowest salinity was recorded in winter (10.42±0.14ppt) (p0.05). The most inorganic nitrogen was determined (ammonium ion: 40.8±2 µg.l^-1) in winter and the highest organic nitrogen (660.6±92 µg.l^-1) in summer (p0.05).The maximum concentrations of total nitrogen were measured at the near-shore stations (640.6±28 µg.l^-1). The annual average water transparency was 4.91±0.24 m and increased in away from the beach (p0.05). However, there was significantly in other groups (p0.05). The maximum of ctenophore abundance and biomass were belonged to the depth of low than 20m (p0.05). The maximum concentration values of OCPs in all groups in seawater were determined in winter (99%) (p0.05). The only DDT group in the seabed sediment had significant difference in different seasons (P0.05). In correlation matrix, the groups of Endosolfan and Drins in seawater and sediment were had equal variance and the changes were included. There was high correlation of between Endosulfan and Drin with DDT group in seawater and with Heptachlor group in the sediment of seabed. Surfactant: Mean surfactant concentration (LAS) between different seasons had significant difference (P0.05). Based on existing standards, Surfactant concentration in the southern Caspian Sea region was not critical

Investigation of growth performance and feeding efficiency of rainbow trout (Oncorhynchus mykiss) in floating cages in the southern Caspian region

Information on the aquaculture of rainbow trout Oncorhynchus mykiss in brackish water, especially in the Caspian Sea, is very limited. In this study, the growth performance and feeding efficiency of rainbow trout in an enclosed environment (5 floating cages) in an offshore farm (5 km distance from the beach) in the southern Caspian Sea region were investigated. This study was performed in Mehrangostar Caspian Sea farm in the Tuskatok area of Nowshahr City, Mazandaran Province, Iran. The fish were introduced to the cages with a density of 21 fish/m3 and also biomass of 3.33 kg/m3 and weight of 110 to 180 g. The duration of the rearing period and the average survival rate of fish were 123-158 days and 95.8 ± 0.5%, respectively.  In addition, the feed conversion ratio and protein efficiency ratio were 0.94 ± 0.01 and 2.66 ± 0.01, respectively. In this brackish farm, the fish average daily growth rate and the average specific growth rate were 3.3 ± 0.9 g/day and 1.07 ± 0.01%/day. Moreover, the average weight of fish yield was 16 kg/m3. The results showed that the growth trend of rainbow trout in the brackish water of the Caspian Sea in floating cages was suitable. Therefore, the introduction of rainbow trout to floating cages in the southern Caspian Sea by different weights, density of 3.33 kg/m3 and also by managing the harvest of 15 kg/m3 in different times or in a whole single catch is quite possible

Effects of rainbow trout farming on water quality around the sea farms in the south of the Caspian Sea

The purpose of this study was to investigate the physical and chemical factors of seawater to determine the water quality index around two marine farms of rainbow trout in the south of the Caspian Sea. Each farm had four floating polyethylene cages with a final fish harvest of 60 tons. The water sampling was performed in January and March 2014 as well as May and August 2015 from around the cages (close: cage shade, 50 m and 100 m; distant: 1000 m) in three geographical directions: east, west, and south. The water quality parameters including pH, temperature, transparency, salinity, electrical conductivity (EC), total dissolved solids, dissolved oxygen, and nutrients (nitrogen and phosphorus compounds) were determined. The results of the analysis of variance of data at both farms showed that changes in physical and chemical parameters of water had only significant differences at the time of sampling (p < 0.05). The highest value of variance in the principal component analysis (PCA; 30.23% from 84.75%) was related to EC, temperature, salinity, total nitrogen, pH, and organic phosphorus. Iran Surface Water Quality Index (IRWQISC) at near and far distances from farms was determined to be moderate (40-55). The main reasons for this result can be attributed to the small-scale and short fish farming period along with the hydrological conditions of the region

The percentage determination of Rutilus frisii kutum (200, 500 and 1000 mg) resistance to salinity, turbidity and decrease of oxygen by usage of the river water at the releasing meantime

The survey effect of salinity, turbidity and dissolved oxygen performed on Rutilus frisii Kutum juveniles with aim, which was determined about survival rate and histological changes in gill and kidney tissues. Juveniles provided from the Rajai's fish propagation center and then examined in Caspian Sea Ecology Research Center laboratory. The juveniles were investigated on three weight group (200-75%) had shown in 400-<600mg weight group with dissolve oxygen: 3.8±0.15SE mg/l. In addition, the lowest survival rates under turbidity stress (95.83%) had shown that in weight group less than 400 mg with turbidity 15600 FTU. Therefore, survival of juveniles was high. However, gill tissue of juveniles under turbidity and salinity stress became short (necrosis) and thick (edema and hyperplasia) in the end of experiments. The juveniles gill tissues were not changes in the river clear freshwater. Therefore, the factors of gill tissue deformation were salinity and suspended particles in the water. However, the structures of kidney in the different groups of juveniles were similar. Nevertheless, juveniles glomerular diameter increased with increasing weight (p<0.05, Duncan test). Furthermore, there was a increasing the internal cavity of the proximal and distal tubules and decreasing of glomeruli in diameter in the transfer of juveniles from freshwater to brackish water. Although the survival rate of juveniles is acceptable in this study, but there was abnormal changes in the structure of them gills. It appears that this change will cause a disruption in trend of juvenile's growth

A study on water quality and physio- chemicals parameters in surface water, underground water and wastewater of Mangol dam basin (Mazandaran province)

This study was conducted to determine water quality of surface water (7 stations), ground water (5 stations) and wastewater (4 stations) at Haraz River during instruction of Mangol Dam in 2009-2010. This study is to follow physico-chemical fluctuation of waters and compared the data obtained with previous studies and standard levels. Results of current study showed that annual mean with standard error of temperature, DO, BOD_5, COD, HCO^3-, CO_3^2-, TA, Ca^2+, Mg^2+, TH, TSS, TDS, Cl^-, PO_4^3-, NH^4+, NO2- and NO3- were observed 12.7 (±0.61) centigrade, 10.13 (±0.12), 2.1 (±0.1), 7.71 (±0.99), 28.1 (±6.1), 14.34 (±1.64), 36.30 (±2.33), 64.66 (±2.34), 28.84 (±1.52), 271.62 (±8.41), 0.37 (±0.03), 0.30 (±0.02), 28.02 (±1.96), 0.06 (±0.01), 0.010 (±0.001) and 0.94 (±0.03) mg/l, pH was 8.00 (±0.02) and EC 0.50 (±0.02) ms/cm in surface water. The annual mean with standard error of temperature, HCO^3-, CO_3^2-, TA, Ca^2+, Mg^2+, TH, TSS, TDS, Cl^-, PO4^3-, NH^4+, NO^2- and NO^3- were observed 21.62 (±1.03) centigrade, 54 (±5), 11 (±5), 57 (±5), 208.6 (±42.5), 109 (±23), 1088 (±165), 0.065 (±0.017), 0.97 (±0.11), 317.8 (±76.2), 0.25 (±0.06), 0.06 (±0.01), 0.0007 (±0.0001) and 0.78 (±0.05) mg/l, pH was 7.37 (±0.07) and EC 1.98 (±0.23) ms/cm in underground water. In addition, the annual mean with standard error of temperatute, DO, BOD5, COD, TSS, TDS, and NO3- were observed 12.7 (±0.61) centigrade, 13.59 (±0.87), 9.80 (±0.12), 2.22 (±0.18), 7.54 (±1.02), 0.50 (±0.03), 0.320 (±0.008) and 0.990 (±0.016) mg/l, pH was 7.95 (±0.02) and EC 0.64 (±0.01) ms/cm in wastewater. Quality of surface water of Haraz River and its branches were almost contained suitable for usual applications, but sometimes the quality of surface water based on BOD5 need to more attention for man uses (such as supply of drinking water). In addition, the quality of surface water was relatively suitable for aquatic based on the aquatic standard levels. Results also showed that water quality index (WQI) was declined from upstream to downstream and some parameters were not in standard ranges. The quality of surface water classified in group II at all stations based on water classification rules which it shows serious water quality changes due to environmental destroyed and domestic, agriculture sewage pollutions. Groundwater were affected by different springs at middle and downstream which they caused change physico-chemical characteristics and water quality. Wastewater was classified from good to moderate based on BOD5. The quality of wastewater was declined at downstream with decreasing DO and pH and increasing BOD5 and pollutants