جستجوی مقالات مرتبط با کلیدواژه « کیفیت آب » در نشریات گروه « شیلات »

Density and seasonal changes of polychaet communities in Tiab estuary, located in Hormozgan province, were studied at different seasons in 2015. Sampling from 4 stations was performed using Van vin Garb (0.04 m2) in triplicates. The average total density of Polychaetes (±sd) was 226.04±193.06 per square meter. 21 families, 28 genera and 39 species were identified. The Cossuridae family had the highest frequency (38.8%). The highest average of Margalef index recorded in station 1 (4.6) and those lowest in station 2 (2.8). Regarding Shannon index, the maximum and minimum value were recorded in station 3 (2.7) and station 1 (2.2), respectively. The results of multivariate CAP analysis showed the effective relationship between environmental parameters and dominant Polychaetes. It was found that Aglaophamus malmgreni was the indicator species of station 4 in all seasons and the most important parameters affecting the distribution of this species were TOM, Silt and NO3. It was also shown that Cossura longocirrata is the dominant species of station 2 in spring and the amount of oxygen and increasing its concentration showed a close relationship with the distribution pattern of this species in the presence of the predominant presence of Prionospio steenstrupi at the same station in summer. Chlorophyll a was as an effective factor in distribution of this species. In the case of Cossura spp. and Nephtys spp. It was found that higher temperature with high concentration of PO4 and at the same time the species are resistant to oxygen deficiency and finally PO4 was identified as the most important factor affecting the distribution of Prionospio banyulensis as the dominant species in stations 1 and 3. The results showed Tiab Estuary with high biodiversity, balanced distribution of Polychaets and dominant sensitive species to pollution and environmental stress and the fluctuation of Polychaete communities is influenced by seasonal fluctuations and quality of water and sediment parameters in this aquatic ecosystem.

In order to evaluate the quality of effluent pollutants from the rainbow trout breeding farms in the selected farms of Kohgiluyeh and Boyer Ahmad Province, water samples were taken from five individual farms during the years 2021-2022. The physical and chemical indicators of water including acidity, biological oxygen demand, dissolved oxygen, electrical conductivity, nitrite, nitrate, phosphate, total suspended solids, total dissolved solids, total hardness, alkalinity, iron, oxygen saturation were measured once in each season from the inlet and outlet water (each treatment with 3 replicates). Based on the results, the range of pH changes (5.93-7.29), biological oxygen demand (6.41-7.56 mg/l), ammonium (0-0.319 mg/l), nitrite (0-0.181 mg/l), nitrate (2.19-19.2 mg/l), phosphate (0. 1-0.18 mg/l), total alkalinity (132-238), dissolved oxygen (3.35-8.11 mg/l), electrical conductivity (311-899 microsiemens/cm), TDS (203.7-607.9), and total hardness (312-157.77 mg/l) were obtained. The results showed that the concentrations of ammonium, nitrite, nitrate, phosphate, EC, and total dissolved solids parameters in the effluent compared to the input from the different farms has increased due to the increase of metabolism, fish density, concentration of nutrients, drugs and disinfectants, intensity and speed of water and the oxygen concentration in the effluent of the farms has decreased due to more metabolic activities than the input from the rearing ponds. Also, the amount of biochemical oxygen demand (BOD) and environmental chemical oxygen demand (COD) were increased and the dissolved oxygen was consumed and its amount decreased due to the increase of organic substances, nitrate, and the provision of oxidation conditions.

In this study, due to the importance of Doiraj Dam Lake, which supplies an important part of agricultural water of Dehloran and Mosian, the assessment of the lake water was carried out in order to develop aquaculture activities and investigate the possibility of fish farming in the lake behind the dam. For this, 4 stations selected, the entrance, before and ater the lake and sampling were done in three seasons by using Van veen grab with with 0.0625 m2. The results of this study were determined based on the biological indicators. In benthic indices, the quality of water was evaluated by determining the species composition and biological value of different species using Shannon-Wiener diversity indices and Hilsenhoff Family Biotic Index (HFBI). The HFBI index in the studied stations ranged from 3.07 to 6.07. In general, based on the biological indicators, in most of the stations and seasons, moderate pollution was observed, which was more evident in the stations before the dam due to its without move nature than the entry and after stations.

Aquaponic system, which is a combination of recycling aquaculture and hydroponic plant cultivation, is consistent with the goals of sustainable development in the aquaculture industry. This experiment was conducted in the form of a completely randomized design with five experimental treatments and each treatment with three replications, which includes the control group: 30 carp (Cyprinus carpio) in a 300-liter tank (without lettuce), A1: 10 lettuce (Lactuca sativa) per m2 (without fish) along with liquid fertilizer, A2: 30 lettuce plants per m2 (without fish) along with liquid fertilizer, A3: 10 lettuce per m2 and 30 fish, and A4: 30 lettuce per m2 along with 30 fish for 60 days. The average weight of the fry fish (50.18 ± 1.23 g) and lettuce plant (10.32 ± 1.49 g) at the beginning of the experiment was the same in the experimental groups. The amount of dissolved oxygen in all experimental treatments was significantly higher than the control group (5.76±1.18 mg/liter) and the highest leve was obtained in A2 treatment (6.80±1.24 mg/liter) (p<0.05). At the end of the experiment, the average total suspended solids (1245.8±60.84 mg/liter), alkalinity (133.64±15.7 mg/liter), nitrite (0.18±0.04 mg/liter), and nitrate (62.40±2.15 mg/liter) were significantly higher in the control group (p<0.05) and the lowest values were seen in A2 treatment. There was no statistically significant difference regarding the performance of growth and feed utilization of the fish between the experimental treatments and the control group (p>0.05). However, the length and final weight of the plant and the relative growth rate of lettuce showed a significant difference between the experimental treatments and the control group (p<0.05) and the highest amount of the mentioned indicators was recorded in A4 treatment. To sum up, the results of this experiment showed that in the aquaponic system containing carp with a density of 100 carp per m2 and a density of 30 lettuce plants per m2, it leads to an improvement in the productivity of carp and lettuce production with proper water quality.

The aim of the study was to determine the quality of the inlet and outlet water of five selected rainbow trout breeding farms in Mazandaran Province (Haraz, Chalous, Tonekabon, and Sari) based on environmental parameters during four seasons in 2021-2022. Forty samples were collected and measured based on standard methods. According to the results, the range of water temperature (3.0-24.0°C), air temperature (2.0-25.0°C), DO (6.16-12.24 mg/l), BOD5 (0.24-2.76 mg/l), COD (2.40-93.70 mg/l), EC (284-783 µs/cm), turbidity (1.12-220-0 NTU), TSS (2-288 mg/l), pH (7.44-8.62), total phosphorus (0.2-2.12 mg/l), phosphate (0.01-0.206 mg/l), ammonium (0.012-0.538 mg/l), ammonia (0.001-0.018 mg/l), nitrite (0.001-0.426 mg/l), nitrate (0.52-6.10 mg/l), fecal coliform count (6-1000 CFU/100ml) and water quality index (WQIIR) (62.0-91.0) were registered. The water quality of this river was placed in class III (low pollution) based on the average parameters of organic pollution (BOD5 and COD) and human activities were not one of the main factors in the increase of organic matter in the river. The concentration of ammonium and nitrite was within the threshold limit, but the concentration of phosphate in all the inlet and outlet stations and in different seasons was more than the maximum limit of unpolluted rivers. The results showed that the WQIIR was in the range of 62-91. 7.5% of the total data and the mean of this index indicated the relatively good quality of the inlet and outlet water of the rainbow trout breeding farms. The highest quality of water, i.e. very good quality, is recorded in 12.5% of all data, which is observed at the inlet water of rainbow trout breeding farms. The outlet quality index of the farms was lower than its inlet, but it was categorized as good quality. The overall WQIIR (77.4±6.6) in all inlet and outlet stations indicates that the water of this farm is suitable for fish and wildlife and also suitable for rainbow trout breeding.

Water pollution is a major global problem that affects plants and living organisms. Factors affecting water pollution include industrial, agricultural, and human pollutants. Qarasu river is very important in terms of pollution due to the use of river water in the agriculture and aquaculture sectors. In this research, the effect of intensive fish farms and the riverbed material was investigated on the abundance of macrobenthic communities. For this purpose, four stations 1) the station upstream and before the fish farms (as control station), 2) the station between the fish farms, 3) the last station of the farms, and 4) the downstream station at a distance of 4 km from the last farm were selected. A sampling of the macrobenthos and riverbeds was done in two seasons, winter and spring, and their frequency was calculated in the sampling stations and months. The highest abundance was related to the family’s Chironomidae (1456 numbers per m2) and Simolidae (2737 numbers per m2) from the Diptera order, which were observed in the effluent of station 2 and station 4 in the winter season, respectively. In addition, the type of the river bed was determined to find the correlation with macrobenthic species. The identified macrobenthos was classified into trophic groups and the relationship with the type of substrate was determined using the Pearson correlation. The correlation of different macrobenthic species with sampling stations and months was found using Canoco software and CCA statistical analysis. The present study showed that the effluent from intensive fish farms had an effect on the abundance of macrobenthos in the Qarasu River, which could be due to the increase in nutrients in the river water from the release of the effluent, and decrease in temperature and decrease in the decomposition of nutrients in the winter season. Therefore, based on the findings, the presence of different functional macrobenthic groups is affected by the type of riverbed and different seasons of the year.

This study was conducted in sturgeon farms along the Caspian Sea coast in Gilan province. The aim was to evaluate the quality of incoming water and effluent of 6 farms. Sampling was performed from April to December 2017. Turbidity parameter by turbidimeter, total soluble solids by TDS meter, orthophosphate and total phosphate by Ascorbic acid method of antimonyl tartrate, ammonium by initial generation distillation, nitrate by cadmium reduction method, dissolved oxygen with Winkler method, coliform bacteria were measured by MPN, oil and fat by gravimetric method and other parameters were measured by standard methods. There was a significant difference in the mean of the parameters in all centers. The average field phosphate was measured 0.17±0.05 mg / l, which was much higher than the WHO standard. Also, the average field effluent turbidity (29.69±1.60 Ntu) was slightly higher than the EPA standards WHO showed. Also, according to the obtained results, the average of total water-soluble solids showed values much higher than the standard of the World Health Organization with an average of 4466.07± 87.70 (mg/l). Another parameter considered in the present study was the average number of coliform bacteria in the effluent, which showed high values compared to the standard. Based on these results, treatment of effluent before its release into aquatic environments is recommended, which in addition to reducing the transmission of microbial contamination, minimizes the risk of atrophy and reduces the effects on the health of aquatic organisms.

Biofloc system is a new technology that used in intensive and semi intensive aquaculture systems. The main advantage of this system is reducing the water use, along with increasing the intensity of production based on heterotrophic bacteria than autotrophic bacteria. The fish were divided into 4 groups in 3 replicates. The first group (A) was reared in normal culture situation as a control. In subsequent treatments, juvenile were rearing in a biofloc system containing various carbon sources, including: maize flour (B), Wheat flour (C) and barley flour (D) as different treatments. One hundred and twoenty fingerlings of common carp with initial average body weight of 15.18±2.07g introduced into the experimental treatments and cultured for 45 days. At the end of the experiment, water quality, growth preformance, and metabolic nitrogen excretion rates compared among treatments. Based on the results, water quality improved among all biofloc treatments compared to the control group (p<0.05). Growth indices significantly improved in all biofloc treatments (p<0.05). The highest growth rate and the lowest feed conversion ratio were recorded in the biofloc system containing barley flour (p<0.05). Ammonia and urea excretion in biofloc treatments were significantly higher than the control group (p<0.05). The highest ammonia and urea excretion rates were recorded in the biofloc treatment containing barley flour (p<0.05). Therefore, it was concluded that the use of barley flour as a carbon source in the biofloc system can be used for rearing of common carp. The use of this carbon source, in addition to improving of water quality, is effective in promoting the growth of common carp in the biofloc system..

TThis study examined the possibility of improving the quality of Macrbrachium rosenbergii larvae and water quality using different levels of Bacillus subtilis and Lactobacillus plantarum probiotics separately in semi-enclosed shrimp culture system. For the research conduction, 24000 newly hatched larvae of the giant freshwater shrimp obtained from the Ghasre-shirin hatchery center and were stocked in the experimental tanks by 40 larvae/liter density for one month. This experiment was designed in 25 liter tanks with four treatments; the first treatment (control without probiotic), the second treatment (106cfu/g), the third treatment (107cfu/g) and the fourth treatment (108cfu/g) in triplicates (for each of probiotics were designed separately). The results showed that with increasing the concentration of Bacillus subtilis probiotic up to 107 bacteria per gram, the parameters including DO, ORP, TDS, LSI and LCI have significantly an increase trend and at higher concentrations these parameters are reduced. It also showed that the bacterial density of Bacillus subtilis can be represented as a limiting factor and in higher concentration of 107 has negative results on larval growth and water quality. In L. plantarum probiotic treatment, increasing the number of bacteria, affected larvae quality and water quality, In the treatment of 108, the best probiotic performance of L. plantarum was recorded. In general, according to the results, the concentrations of 107 and 108 for B. subtilis and L. plantarum probiotics are respectively recommended in the hatchery centers of the giant freshwater shrimp.

Ornamental fish keeping is the second most popular hobby in the world, and its popularity is growing every day. The ornamental fish farming industry provides entrepreneurship and income generation opportunities, so it is important to focus on various aspects of ornamental fish farming. Several physical and chemical parameters of water are discussed in this study, including pH, hardness, ammonia, nitrite, and nitrate, as well as optimal water conditions. The physical, chemical and biological parameters of water are interrelated in aquatic ecosystems. Thus, physical and chemical parameters of water must be analyzed together. The ornamental fish production centers have greater expertise than edible farmed fish in terms of water quality management since ornamental fish are sensitive to low water quality. Water quality management is more critical when it comes to ornamental fish since they are kept in greater densities than edible fish. In tanks that hold a large number of fish, water quality factors such as pH, water hardness, and excess nitrogen compounds must be measured daily, so the producer needs to take measures to manage them. It is essential for high density aquarium fish rearing tanks to monitor water quality daily, change the water regularly, and ensure adequate aeration.

The most important factors affecting water quality are its physical, chemical and biological properties. Considering how water quality is one of the main and influential factors in aquaculture, in this study, the trend of fish growth and changes in water quality in dual-purpose rainbow trout farming ponds in Sistan region were studied. For this purpose, biometry of fish and water quality conditions were performed by sampling fish and water, respectively from five pools in Zabol, Zahak, Nimroz, Hamoon and Hirmand cities. Sampling was performed monthly from December to April (simultaneously with the breeding period) from all pools. The highest and lowest production rates are related to Hamoon pools (1039.44 kg) and Zahak (913 kg), respectively. The highest final length and weight of fish was recorded in Hamoon pool with 26.3 cm and 366 g. Measured factors included water temperature, dissolved oxygen (DO), pH, salinity, transparency, electrical conductivity (EC), hardness, alkalinity, nitrite, ammonia, sulfate, carbon dioxide (CO2), phosphate and nitrate. The results showed that the amount of dissolved oxygen between 7.76 to 8.34 mg.l-1, phosphate and nitrate between 0.4 to 1.6 and 0.4 to 1.9 mg.l-1 respectively, EC between 1/95 to 5.5 mmhos.cm-1 and pH ranged from 7.5 to 7.93. These results showed that water temperature changes, as the most important factor limiting the breeding of rainbow trout in this region, in the cold seasons of the year is in the optimal range for breeding this fish and in different ponds of Sistan region is not considered a limiting factor. Changes in water temperature during the breeding period in these areas varied between 14.78-15.24. Other water quality indicators were also in the optimal range for breeding this fish and not much change was observed in the pools of this area.

The purpose of this study was to investigate the effects of using two levels of Sanyar prebiotics (powder and liquid) on growth performance, feed productivity, digestive enzyme activity and non-specific immunity of Cyprinus carpio juveniles in the biofloc system. Common carp (10.09 ± 0.45 g) were stocked into 18 tanks (35 L) in six treatments for 60 days, including: Control treatment without additive and with clean water (C), Control treatments without additive with Floc (FC), Floc treatments with 0.1 and 0.2 g (FP1 and FP2) powder prebiotic and Floc treatments with 1 and 2 ml (FL1 and FL2) liquid prebiotic per 100 g of basic diet. Water parameters are maintained at the standard level for this species. Total ammonia concentration (TAN) was statistically significant between experimental treatments. The growth of fish was obtained significantly higher and the feed conversion ratio was lower in FP1. The highest intestinal protease activity (8.42± 0.05) was obtained in FP1 treatment. The lowest serum cortisol and glucose were observed in FP1. The immunoglobulin and lysozyme serum in FP2 and FL1 were significantly higher than other treatments. The results of this study showed that the use of 0.1 g of Sanyar prebiotic powder per 100 g of basic diet in the biofloc system could improve growth performance, and the immune status of C. carpio.

In current study, the effect of different times of molasses addition on water quality and immune performance of Nile tilapia (Oreochromis niloticus( mucus in biofloc system with limited water exchange was investigated. Nile tilapia with an average weight of 1.53 g was cultured in fiberglass tanks (circular cross section) with a volume of 130 liters of water at a density of one fish per liter for 37 days. Five experimental groups were considered including a control (without biofloc) group without carbonaceous substance addition and four biofloc treatments with molasses added daily (biofloc 1), once every two days (biofloc 2), once every three days (biofloc 3) and once every four days (biofloc 4). 2.5 ml/l microbial mass was added as a starter to biofloc treatments. Also, molasses carbonaceous material (65% of the input feed) was used to adjust the carbon to nitrogen ratio. According to the results, water quality in biofloc treatments showed that the lowest amount of total ammonia nitrogen (0.23 mg/l) and the highest amount of nitrate (25.5 mg/l) were obtained in biofloc 1 treatment (daily molasses addition), that showed a significant difference with other treatments (p<0.05). Based on the results of immune function of tilapia mucus, the lowest amount of total immunoglobulin (43.66 mg/100 ml) and lysozyme activity (17.33 ml/min) were observed in the control (without biofloc) group (p<0.05). Generally, the current research showed that the water quality in the biofloc system is improved with the addition of molasses on a daily basis and also the immune function of Nile tilapia mucus in biofloc system is more active than the normal system without microbial floc.

In the present study, the effect of different carbon sources on water quality and growth performance of common carp (Cyprinus carpio) fingerlings by adding synbiotic into biofloc system (BFT) were investigated for 45 days. Three experimental treatments (B, C and D) containing corn, wheat and barley flours together with a control group (A) were prepared. The used synbiotic was a mixture of Bacillus circulans and B. lichiformis along with a Celmanax liquid commercial prebiotic at a final concentration of 1.5×108 CFU/ml to each treatment. Fish fingerling (15.98±1.93 g) was distributed randomly into 12 tanks (4 treatments × 3 riplicated) with 30 liters of capacity. At the end of the experiment, the nitrate, total hardness and total suspended solidsin in all treatments significantly increased compared with the control (P<0.05). While, the dissolved oxygen in all treatments was lower than the control (P<0.05). NO3 was measured higher than the control only in corn and barley treatments (P<0.05). The highest final weight (40.31±11.20 g), SGR (1.59±0.27%), TGC (0.98±0.09%), condition factor (2.21±0.17), FCE (106.09±29.47%), PER (4.71±1.31), PEL (18.22±5.04) and PEE (0.13±0.04) were recorded in corn flour treatment. However, the lowest feed conversion ratio (1.01±0.25) and relative feed intake (11.94±3.79%) were observed in corn flour treatment (P<0.05). The highest excretion rates of ammonia (1011.45±14.27 mg.kg-1BW.day-1), urea (25.30±3.57 mg.kg-1BW.day-1) and energy wast by excretion rates of ammonia (25.36±3.50 mg.kg-1BW.day-1) and urea (6.21±0.78 mg.kg-1BW.day-1) were recorded in barley flour (P<0.05). In conclusion, the results demonstrat that the use of corn flour with synbiotic in the BFT system, compared to other carbon sources was more effective to improve the water quality and promoting of growth preformance of common carp fingerlings.

An experiment was conducted to determine the efficiency of two kinds of substrata (Polypropylene and cotton sheet), as biofilter media on removal of N-compounds and fish growth in a recirculating culture system for a 6-week period. Rates of survival was significantly different between treatments(p < 0.05). The mean (± SD) initial individual weight of fish was 3.4 ± 0.20 g and the fish attained to 9.19 ± 0.53 and 7.79 ± 0.38g in treatments with cotton sheet and polypropylene, respectively at the end of experimental period. Concentration of total nitrogen, total ammonia-N and nitrate were significantly different (p < 0.05) between treatments at the end of the experiment. Concentration of total ammonia-N reached to 0.050 ± 0.0021 and 0.054 ± 0.0039 mg L-1 in cotton sheet and propylene treatments, respectively. The electro-conductivities were significantly different and attained to 970± 0.32 and 900 ± 51.3µmos/cm in treatments with cotton sheet and propylene, respectively, at the end of experiment(p < 0.05). It was concluded that cotton sheet, can be used as an efficient bacterial substrate or medium in a recirculating carp culture system.

This study aimed to investigate the effect of reduction of feeding rates on water quality, growth performance, and immune response in bio-floc common carp (Cyprinus carpio) and clean water systems. Fish (9.04 ± 0.44 g mean initial weight) were stocked into 18 tanks (50 L) through a 2×3 factorial design consisting: The use of commercial feed of 100, 85 and 70% (2.5, 2.12 and 1.75 % of body weight) in bio-floc groups (BF1, BF2 and BF3) and non-floc groups (NF1, NF2 and NF3) for 60 days. At the end of the experiment, Total ammonia nitrogen (TAN) concentration was significantly lower in bio-floc compared to non-floc. The highest fish growth performance and the lowest feed conversion ratio were obtained in the bio-floc groups with 2.5 and 2.12% feed intake (BF1 and BF2), respectively. After 60 days, the serum lysozyme and total immunoglobulin levels were significantly increased and serum cortisol levels decreased in the bio-floc groups. This study showed that reducing the feeding rates (2.12 to 2.5% of body weight) have a positive effect on growth performance and immune response in bio-floc common carp culture system compared to clean water system.

In the last two decades, the Caspian Sea has faced various ecological events, such as harmful algal blooms and increasing in the trophic level. It is necessary to conduct monitoring studies in this water body, because of applying the Caspian Sea for fisheries activities. The objectives of the present paper are the study of algal bloom potential and trophic level in the Iranian coastal of southern Caspian Sea up to 30m depth, during the year of 2018-2019 as well as the comparison of the obtained results to the condition in previous years. Boundary lines for the beginning of blooms (annual median+5%) based on the chlorophyll-a concentration, abundance, and biomass of phytoplankton were obtained 2.02 (mg/m3), 176 (million cells/m3), and 312 (mg/m3), respectively. The lowest percent frequency of bloom (13%) was recorded in spring and summer based on the chlorophyll-a, abundance, and biomass of phytoplankton, respectively. According to calculations based on the accumulation of the aforementioned parameters, water has excellent quality (oligotrophic state) in summer and moderate quality (mesotrophic state) in other seasons. An interannual study of trophic states showed oligotrophic, mesotrophic, oligo-mesotrophic, and mesotrophic level in 1996-97, 2009-10, 2013-2014, and 2018-2019, respectively. The highest seasonal abundance of species (187 cells/ml) was recorded in Pseudonitzschia seriata. This species is considering a serious ecologic problem and decreasing water quality in the winter season. The bloom potential of Pseudonitzschia seriata was obtained in the “medium density” group. It should be noted that the increasing trend of inter-annual trophic levels is the alarm of environmental health and show the ability of the ecosystem to thrive the harmful algal blooms. The environmental alarm is more emphasized in the central region (with a history of macroscopic toxic algal blooms) because the water quality in the central area (medium quality) was lower than in the eastern and western areas.