The most important goals of mechanization in aquaculture are to reduce the production costs and improve profitability, reduce production risk, observe health and prevent diseases, and observe environmental aspects in production, improving quality of farm effluents and proper nutritional management leading to higher level of productivity. This research was conducted aiming at investigating the efficiency of mechanization on quality of wastewater in dual-purpose rainbow trout culture farms in Markazi province of Iran. 30 dual-purpose rainbow trout culture farms with high production capacity and more ponds located in 5 cities of the Markazi province were selected and their mechanized tools were determined. The physical and chemical factors of inlet and outlet water, including dissolved oxygen, pH, nitrite, ammonia, nitrate, phosphate and total suspended solids were measured. Although water factors of most of the studied farms were acceptable for raising rainbow trout, various variables such as amount of production, health management, quality and quantity of washing ponds, output and discharge improper pools, failure to use siphons between two outlets, failure to implement fishing patterns, improper siphonage and drainage are effective in farm performance and disrupt the balance of physical and chemical factors of water and challenged the efficiency of mechanized devices and equipment used in the farms.

This research was aimed to investigate the effect of mechanization on the growth and nutritional indices of dual-purpose rainbow trout farms in the Markazi province (Iran). 5 cities with high production capacity and pools numbers were selected in cooperation and according to the provincial fisheries. The experts were sent to the farms to prepare necessary documents, complete the questionnaire regarding the existing and active mechanization equipment and the technologies used, the production in the farm, the type of food consumed, the factory producing the feed, type of feeding (automatic, manual), use of feed dispensers, the same size of fish to avoid competition and the dominance of larger fish during feeding, the condition and method of food storage. Growth and nutrition indicators of farms were determined. some mechanization equipments of farms included as aeration tower (90%), drum filter (23.33%), Feed storage equipped with a fan (30%), pallet in the feed store (66.67%), sediment pool (53.33%) and grading (76.67%), respectively. Mechanization and the type of food had effect on the growth process of fish, and the improvement of nutritional management, the use of resources more efficiently with the optimization and correct selection of the type, amount, method of feeding increases the economic productivity of dual-purpose rainbow trout culture ponds in the Markazi province. This study showed that various variables such as the amount of production, quantity and quality of food, health management, density, fish weight, implementing fishing patterns, construction of a sediment collection pool, fish grading, proper storage in optimal and hygienic conditions on pallets, installation of aerators and installation mesh in the windows in the feed store, periodic testing of the physico-chemical and microbial parameters of the water, can be effective in the farm's performance.

Urmia Lake has been suffered from continuous water withdrawal for more than 2 decades. It is the largest habitat of a unique brine shrimp species, Artemia urmiana, first reported by Gϋnther. This study was performed to determine if harsh environmental conditions has eliminated the A. urmiana from the lake. Six sampling sites were selected in northern and southern parts of the lake. Two stations were not accessible through the sampling campaign due to drastic water withdrawal and marshy path. Samplings were performed monthly from March 2022 to February 2023. Electeric Conductivity (EC) and Total Dissolved Solids (TDS) were determined by EC-meter WTW model LF 320 and multi-meter WTW model 3410, respectively. The water salinity was measured by refracto-meter ATAGO (Japan) model S-28E. Water level, surface area and volume were extracted from East Azarbaijan water resources management company web site. The brine shrimp samples were collected by pulling a net (25×100cm - 100 μ mesh size) in definite distance. The Artemia samples were studied under stereomicroscope Nikon. In this study, we did not observe any types of Artemia biomass (Nauplii, Meta-nauplii, young and adult Artemia). Only Artemia cysts was observed in Lake Urmia. In summer and autumn (dry season) cyst density were 0.00216 ± 0.0017 No/l and zero, respectively, whereas in spring and winter (wet season) were 0.364 ± 0.259 and 0.149 ± 0.084 No/l. In general, the results of this study show that the surface area, volume and level of the lake had the highest effects on the cyst density.

The effect of Rainbow trout fish farms effluents on macroinverebrate communities and water quality of Peredanan river (West Azarbajan)

The comparison of growth, survival rate and behavior of Oscar fish (Astronauts ocellatus) fries fed by Artemia urmiana, earthworm and beef heart supplemented diets

Aras Dam Lake is a strategic aquatic ecosystem in Iran and there are reports of toxic phytoplankton blooms in this reservoir. This study was performed to determine the effect of meteorological variables on the formation and expansion of toxic phytoplankton communities in Aras dam reservoir. The data of this project have been obtained using field studies and satellite data (MODIS and Sentinel-2). Sampling to determine the composition of phytoplankton communities in the area was carried out seasonally in two time periods from 2003 to 2014, and environmental assessments were also performed based on meteorological and satellite data over an 18-year period (2003–2020). The Chlorophyll-a content was obtained from MODIS and correlated with meteorological data. The statistical analysis showed that the highest coefficient of determination is related to the correlation of chlorophyll-a and Evaporation (R2 = 0.86). Also, the relative root mean square error is equal to 18%, 18.1% and 21.2% for the chlorophyll-a -SST, chlorophyll-a -wind and chlorophyll-a -Evaporation relations, respectively. Moreover, in a supplementary study, correlation between the chlorophyll-a content with selected meteorological variables including evaporation, wind speed and water surface temperature were investigated seasonally. The results showed that the trend of changes in chlorophyll-a content with three considered variables are parabolic functions and chlorophyll-a -Evp (R2 = 0.86, MAPE = 15.2%) model indicates better performance. The results also showed that the eutrophication rate of the reservoir during lockdown period increased in comparison with the same time at pre-pandemic period, which can be related to increase of incoming waste loads in this reservoir.

Urmia Lake is one of the largest permanent hypersaline lakes in the world. The lake can be characterized as an oligotrophic lake concerning phytoplankton production. Due to agriculture development and low precipitation in recent years in Urmia Lake’s basin, the water level has declined as much as 4 m compared to 15 years ago. Water level decline influence the phytoplankton population through increased water salinity. Furthermore, Artemia urmiana Gunther as the major zooplankton in hypersaline lakes may affected on phytoplankton populations. Therefore, the purpose of the present study was evaluation how A. urmiana impact on the phytoplankton structure in Urmia lake. Eight stations were selected in south and north parts of the lake. Sampling were performed monthly during May 2018 to June 2020. Phytoplankton structure were analysed by inverted microscopy. Environmental parameters water temperature, pH, salinity, water level, Total Dissolved Solids (TDS), Electric conductivity (EC) were determined in each sampling. Seasonal fluctuations of algal abundance influence A. urmiana population in temperate large hypersaline lakes such as Urmia Lake. However, A. urmiana grazing pressure has significant effects on microalgal density. This study indicated that salinity is not increased directly by water level decline in Urmia Lake.

Urmia Lake is the second largest hypersaline lake in the world, covering average 5000 km2 when full. The lake moderates extreme temperatures of the region and many tourists visit it for recreation, swimming and mud treatment during summer. During last two decades, increased demands for agricultural water in the lake's basin and recent droughts have shrunk the lake dramatically, exposing 60-80% of the lake bed. This review indicates that increased water demand in the lake basin, recent droughts and global warming are the main drivers for the Urmia Lake shrinkage. The Iranian government has made restoration of this remarkable ecosystem a crucial priority. Here we concluded the causes and consequences of Urmia Lake shrinkage and provide a brief discussion of the impacts on its fauna and flora, coloration, wetlands and islands. As Urmia Lake shrinking persists, many environmental, economic and social advantages will be completely lost in the lake's basin. Keywords: Urmia Lake, restoration, wetlands, shrinking, ecological disaster.

Mighan Lake is located 8 kilometers northeast of Arak city. Lake surface area is 112 km2. Dunaliella salina (Dunal) Teodoresco composing main phytoplankton population and food chain in the lake. Salinity depending on season and water input is between 20-120 g/l. This study evaluated the impact of salinity and physicochemical factors on the lake’s phytoplankton communities. Sampling was done monthly during March to December 2019. Species and phytoplankton density were determined by inverted microscopy. Twelve algal species were identified which D. salina consisted 87.3% of phytoplankton composition. Indeed, salinity as a major limiting factor reduced phytoplankton diversity in Mighan Lake.

Hypersaline environments are important natural assets that have significant economic, ecological, scientific and natural value. Management and protection of these variable ecosystems depend on understanding the influence of salinity on biological productivity and community structure. The object of the present study is to investigate the relationships between two basic components in Urmia Lake i.e. microalgae and physico-chemical parameters, particularly salinity level in order to provide a better understanding dynamics of this unique ecosystem. 3 sampling sites were selected in north and south of Urmia Lake. Samplings (2 samples in each site) were carried out monthly from April 2018 to October 2019. Water level, salinity, Electrical Conductivity (EC), Total Disolved Solids (TDS), pH, transparency, Phosphate and Nitrate (PO4 -3 and NO3 -) were analyzed. phytoplankton species composition and density were also determined. Statiscal analysis were performed by PAleontological STatistics (PAST) version 3.04. Totally, seven algal species were identified in Urmia Lake in this study. Bacillariophyta with 5 species was the most abundant algal group in the lake. Chlorophyta and Cyanobacteria both had 1 species, however, Dunaliella salina as the only representative of green alga alone composed about 99.5 percent of total algal density of Urmia Lake. This study indicated that salinity, TDS and EC have the highest effects on phytoplankton population structure and Dunaliella spp. dominance in Urmia Lake. However, other factors such as PO4 -3 and NO3 might have been masked by three main factors.

Skin coloration has a key role in ornamental fish trade. The amount of carotenoid pigments has a decisive influence on the color of muscle and skin of edible and ornamental fish. Also, there is a need to add carotenoids in the diet of cultured fish. Live foods especially Artemia play an important role in ornamental fish feeding regarding growth and skin color and thus marketing. In this study, the effects of different diets including concentrate, 67% concentrate and 33% frozen earthworm, 67% concentrate and 33% frozen Artemia urmiana as well as 67% concentrate and 33% frozen cow heart on total carotenoids and carotenoid pigments of Oscar fish skin was studied. A total of 360 Oscar fish with initial weight of approximately 1.6 g were cultured for 2 months in 4 feeding treatments, each in 3 replicates. The total carotenoids, astaxanthin, cantaxanthin and β-Carotene contents of the fish were analyzed. Results indicated that in all treatments asthaxanthin was the highest amount of carotenoid pigmentation of Oscar skin. Adding Artemia urmiana in the diet induced the higher total carotenoid and asthaxanthin levels in the skin of Oscar fish.

This study was performed to determine relationship between dam reservoir physico-chemical parameters and the phytoplankton structure in 7 reservoirs of west Azarbaijan province. Samplings were carried out during July 2016. Samples were collected for phytoplankton identification and enumeration, chemical analyses at each sampling site. Principal component analysis (PCA), Detrended Correspondent Analysis (DCA) and two-way unweighted pair group method with arithmetic mean (UPGMA) were performed to determine the environmental variables affecting phytoplankton community dynamics. Seventy-three species belonging to five divisions were determined during this study. The result of PCA and DCA was confirmed by UPGMA analysis, in which three main groups were clustered on the basis of their correlation with phytoplankton community changes and environmental parameters. Totally, highly disturbed reservoirs contained different phytoplankton community than undisturbed ones.

The effects of water physico- chemical factorson phytoplankton communities of Shahrchaidam reservoir were studied. 6 samplingsites were chosen along Shahrchai dam and surfaceand deep layers were sampled during 3 seasonsin 2015-2016. In this study, phytoplanktonsamples were fixed with 4% formalin and transferredto laboratory. Identification and enumerationof the phytoplankton were performed byinverted microscope equipped with 5 ml countingchamber. Totally 34 species of phytoplanktonbelonged to Green algae, Diatomes, Cyanobacteriaand Euglenophyta were determined.Statistical analysis was carried out by PCA andUPGMA methods. The analysis of data by PCAshowed that first and second axis created 99%of changes alone. There were 3 completely distinctgroups of samples regarding the samplingseasons. The most effective physico- chemicalfactors influenced the phytoplankton communitieswere water transparency, EC and water temperature.

Today, harmful cyanobacerial bloom is consideredas a main problem in freshwater ecosystemsall over the world. The Microcystis is an importantgenus in cyanobacteria composed of about 23species. This genusforms various shaped coloniesincluding spherical or oblong cells which wholecolony is surrounded by a mucilage sheath. Manypopulations and species of the genus produce severblooms and often toxins in eutrophic freshwaters.The genus Microcystis has been defined based onmorphological, morphometrical and genetical criteria,however, its classification under the genuslevel is still indistinct and presence of traditionalmorphological species within the genus is doubtful.Therefore, determining of the natural diversityunder the genus level in Microcystis has a crucialimportance. The purpose of this study was to determinethe species of Microcystis in Aras reservoir.The samples were collected from 6 sampling siteson 18 August 2013. Morphological and morphometricalstudies of Microcystis was carried out byNikon 50i microscope equipped with Nikon DSFicamera and Nikon monitor with length measurmentsoftware. Principal Component Analysis(PCA) and two-way Unweighted Pair GroupMethod with Arithmetic Mean (UPGMA) byPAleontological STatistics (PAST) version 3.04were performed to determine biosystematics variationsbetween Microcystis populations. The resultsindicated that Microcystis from Aras reservoirwas composed of two distinct groups based on theshape and size of cells, colony form, presence andabsence of gelatinous sheath around the colonies,etc).These two groups may be considered as twomorphospecies of M. botrys which are separateddue to different ecological factors.

The Aras reservoir, located in the north-west of Iran, plays an important role in fisheries, drinking and agricultural water supplies and recreational activities in the region. This study was performed to characterize the seasonal fluctuations of phytoplankton communities and their relationship with environmental factors in the Aras reservoir from August 2013 to May 2014. Sampling was carried out seasonally from 5 sampling locations. In each location three samples were taken for phytoplankton identification and enumeration, chemical analysis and chlorophyll a determination. In total, 72 species belonging to 5 divisions were determined. Cyanobacteria contained the highest density (74%) during the study period with Pseudanabaena limnetica as the most abundant species. This group retained its dominance the whole year round which indicated the poor quality and high nutrient load of the Aras reservoir, mainly due to human activities. On average, Trophic State Index (TSI) showed that water in the reservoir was eu-hypereutrophic. The results indicated that phytoplankton density negatively correlated with Secchi disc depth (R-2 = -0.479), total alkalinity (R-2 = -0.564), total hardness (R-2 = -0.727) and HCO3 concentration (R-2 = -0.589). On the other hand, there was a positive correlation between the phytoplankton density and TP (R-2 = 0.734). A comparison between the present and a previous study indicated that the cyanobacterial bloom pattern in the Aras reservoir has shifted from warm season toward an all year round cycle which in addition to basin pollution due to anthropogenic activities, can be related to global warming and climate change.

This study was performed to compare the efficiency of six microalgae namely Dunaliella tertiolecta, Tetraselmis suecica, Nannochloropsis oculata, Chaetoceros sp ., Chlorella sp. and Spirolina sp . on the growth, survival rate and reproduction efficacy in Artemia urmiana in laboratory conditions. Artemia cysts were harvested from Urmia Lake and hatched according to the standard method. Live microalgae were cultured using the f/2 culture medium. Artemia survival was determined in treatments on days 8, 11, 14, 17 and 20. A highly significant difference (p <0.01) were found among three microalgae in terms of length growth, survival rates and reproduction characteristics in A. urmiana. In spite of higher length growth of A.urmiana fed on N. oculata than A. urmiana fed by T. suecica but survival and reproduction in the latter was better than the first treatment. In general, D. tertiolecta was more efficient than other microalgae examined in the present study on A. urmiana concerning not only to growth and survival but also to reproduction mode. So, it is preferred to feed A. urmiana

AbstractThis study was undertaken to determine the phytoplankton structure and the environmental variables comprising the driving factors leading to cyanobacterial blooms in Aras Reservoir. Sampling was carried out seasonally at five sampling sites along the main body of the reservoir. Samples were collected for phytoplankton identification and enumeration, chemical analyses and chlorophyll‐a (Chl‐a) concentrations at each sampling site. Principal component analysis (PCA) and two‐way unweighted pair group method with arithmetic mean (UPGMA) were performed to determine the environmental variables affecting phytoplankton community dynamics. Seventy‐two species belonging to five divisions were determined during this study. Cyanobacteria contained the highest density (74%) during the study period, with Pseudanabaena limnetica being the most abundant species. The Shannon diversity index was low (0.44–1.87), indicating a high level of cyanobacteria dominance and eutrophic water status. Principal component analysis indicated that total phosphorus and temperature were significantly associated with cyanobacteria growth. Two‐way clustering by UPGMA indicated a close relationship among sampling sites during the same season from the perspective of the phytoplankton density. The findings of this study suggested Aras Reservoir could be highly affected by agricultural runoff and untreated sewage loadings. Thus, the proper use of fertilizers and sewage treatment should be taken into account in considering effective conservation and management plans.

In this study, enriched emulsion of Artemia was made with reverse engineering using home country potentials. The ingredients of imported Selco were analyzed in chemistry lab of Uremia University. Then different resources containing animal oils with highly unsaturated fatty acids, from waste materials and by products of south water resources aquatic animals harvest (liver oil of shark), vegetable oils provided from wastes of oil extraction factories and regional vegetable oils such as sunflower were studied. Fatty acid profiles of extracted oils from internal sources were analyzed by Gas Chromatography (GC). Provided emulsions were compared with foreign samples as control treatment. Then, the samples were analyzed by GC. The next step was to perform pilot project tests. In the pilot tests, first Artemia enrichment operation with enrichment emulsions was carried out by interior potential and foreign resources according to standard methods. All data were analyzed using SPSS software by one way ANOVA and Duncan test. The enriched nauplii were analyzed chemically by GC. The results showed that the absorption of emulsions in Artemia in interior and foreign samples were 37.47% and 25.30%, respectively. Then, enriched live Artemia nauplii immediately transferred to Ziveh cold water fish farm containing 500 newly feeding larvae of Oncorhynchus mykiss consisted of 3 treatments and a control larval treatment, in which some biologic performances like the mortality rate, growth, Feed conversion ratio and survival rate were determined. Abnormality in larvae, were studied. The results revealed that treatments 1, 2, had a significant difference with treatments 3, 4, on survival rate, growth coefficient, mortality rate and abnormality. The survival rate and growth coefficient and mortality rate and abnormality of treatment 3 had not any significant difference with control. Final results showed that there is the potential of Selco enrichment oils production similar to foreign samples by interior potential.

In this study, enriched emulsion of Artemia was made by reverse engineering using home country potentials. The ingredients of imported selco were analyzed in chemistry lab of Urmia University. Then different resources containing animal oils with highly unsaturated fatty acids, from waste materials and by products of south water resources, aquatic animals harvest (liver oil of shark), vegetable oils provided from the wastes of oil extraction factories, regional vegetable oils such as sunflower were studied. Fatty acid profiles of extracted oils from internal sources were analyzed by GC. Provided emulsions were compared with foreign samples as controls. Then, the samples were analyzed by Gas Chromatography. The next step was to perform pilot project tests. In the pilot tests, first Artemia enrichment operation with enrichment emulsions was carried out by interior potential and foreign resources according to standard methods. All data were analyzed using SPSS software by one way ANOVA and Duncan test. The enriched nauplii were analyzed by G.C. The results showed that the absorption of emulsions in Artemia in interior and foreign samples were 37.47% and 25.30%, respectively. Then, enriched live Artemia nauplii immediately transferred to Ziveh cold water fish farm containing 500 newly feeding larvae of Oncorhynchus mykiss consisted of 3 treatments and a control larval, in which the mortality rate, growth and survival rate were determined. Abnormality in larvae, were studied. The results revealed that treatments 1, 2, had a significant difference with treatments 3, 4, on survival rate, growth coefficient, mortality rate and abnormality. The survival rate and growth coefficient and mortality rate, and abnormality of treatment 3 had not any significant difference with control. Final results showed that there is the potential of selco enrichment oils production similar to foreign samples by interior potential.

Artemia is the most widespread live food used in the production of different stages of many aquaculture organisms. It is a non-selective filter feeding organism. Generally, microalgae are the most favorable feeds for Artemia, particularly when the algal species have suitable size, digestibility and nutrient values. This study was performed to compare the efficiency of three microalgae namely Dunaliella tertiolecta, Tetraselmis suecica and Nannochloropsis oculata for growth, survival and reproduction efficiency of Artemia urmiana in laboratory conditions. Artemia cysts were harvested from Urmia Lake and hatched according to standard methods. Live microalgae were cultured using the f/2 culture medium. Artemia survival was determined in treatments on days 8, 11, 14, 17 and 20. The results indicated a significant difference (P<0.01) among three microalgae in terms of growth, survival rates and reproduction characteristics in A.urmiana. In spite of higher length growth of A.urmiana fed on N.oculata than T.suecica but survival and reproduction in A.urmiana fed on T.suecica was better than the first treatment. In general, D.tertiolecta was more efficient than T.suecica and N.oculata on A.urmiana, hence, it is preferred for feeding A.urmiana.