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This study surveyed Intrabasin variation in the growth models of C. capoeta in 5 streams of Gorganroud River basin during the reproduction season between April and May, 2010 and 2011. A total number of 1500 specimens were caught through electro-shocking. Total length, total weight, sex and b-value were determined. Total length ranged between 4.1 and 20 cm and total weight ranged between 0.81 and 108.34 g in Pishkamer and Tilabad streams, respectively. The growth models were estimated separately for each sex. The b-value ranged from 2.90 for the males of Pishkamer and Tilabad to 3.13 for the females of Chelchai. Growth model was positive allometric (b>3) for most of the females, while the males had different growth models. A comparison between the b-value of the streams can aid the identification of the factors contributing to the growth model of the populations. In fact, different types of habitats differ in their general environmental conditions which can cause reactions. This reflects a change in the body form with population. This variation in the allometry coefficient of C. capoeta suggests different growth strategies for the populations.

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In order to identify and estimate the population of fish and its relationship with environmental factors, sampling was done seasonally from summer 2009 to spring 2010 by electrofishing (DC, 200-300V) in Shirabad stream. Results show four identified species of fish including: Spirlin (Alburnoides eichwaldii), Sand Goby (Neogobius fluviatilis), Loaches (Paracobitis malapterura) and Chub (Squalius cephalus). The estimated population was calculated as for density in different seasons. Sand goby and Spirlin were caught in different seasons in a way that Sand Goby were estimated as the dominant species with the highest frequency (52%) in all four seasons. However, in some seasons Loaches and Chub were observed. In Shirabad stream, the presence of Sand goby was significantly and positively correlated with turbidity and water temperature and the presence of Chub had the highest positive correlation with pH levels. In addition, the presence of Spirlin were positively correlated with stream width, channel incision and water depth The presence or absence of Loaches were correlated to environmental factors such as phosphate and water discharge rate.

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The total number of 460 specimens of Cyprinus carpio was collected from the product of fishery corporation companies located in Gorgan Rud estuary between December 1987 and June 1988. After doing the biometry processes, age of specimens was determined using scales and the fecundity of the fish is calculated by weighting and numerical methods. The mean length and weight of the fish were 466.7±79.92 mm, 1494.4±813.38 g and 430.04±85.26 mm, 1105.62±694.95 g for female and male ones, respectively. Also, the mean values of condition factor were 1.07±0.09 in females and 1.55±0.17 for males. In addition, the dominate age group was observed as 5+ (33.48% of total numbers) and 6+ (45.2% of total numbers) for females and males, respectively. Weight- length relationship showed a positive allometric growth (b=3.025) for females and a negative allometric growth (b=2.92) for males. The Von Bertalanffy growth equations were calculated as: Lt= 1054 (1-e-0.11(t+0.041)) and Lt = 901(1-e-0.12(t+0.402)) for females and males, respectively. Results also showed that growth performance index was equal to 5, mean gonadosomatic index in females was 16.98±2.46 and the maximum value was observed during the end of April to May and finally, average absolute fecundity for Cyprinus carpio was 185254±75778 eggs.

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The outbreak of diseases is a limiting factor in fish farms. A large number of plants are being used in traditional medicine for the treatment and control of diseases. One of such plants is ginger (Zingiber officinale). In this study antimicrobial effects of alcoholic extracts of ginger on six important positive and negative gram bacteria including Vibrio alginolyticus, Vibrio parahemolyticus, Micrococcus luteus, Staphylococcus epidermicus, Bacillus cereus, Stereptococcus zoo epidermicus were analyzed. Extraction was conducted on rhizomes of Ginger using 80% ethanol in laboratory. In order to assess antimicrobial effects of the ginger extract on the studied bacterial species, diffusion test on agar media using disk method on studied bacteria was conducted. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were determined by serial dilution assay using Liquid culture in 96 wells microplates. Results indicated that ginger alcoholic extracts have inhibitory effects on the bacterial growth and is lethal for all bacterial strains. Also ginger alcoholic extract has the most and the least growth inhibitory and lethal affects on Vibrio alginolyticus and Vibrio parahemolyticus, respectively.

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This study focused on investigating the synergistic effects of potassium sorbate and Lactobacillus casei in rainbow trout fry (Oncorhynchus mykiss) with the initial weight of 2.45±0.05.A completely random designed  experiment was carried out for 8 weeks using six treatments, including: commercial diet (control), diet 10⁷ CFU/ g bacteria (treatment 1), a diet containing 0.5% of potassium sorbate (treatment 2), a diet containing 1% potassium sorbate (treatment 3), the composition of the diet with %0/5 of potassium sorbate and 10⁷ CFU/ g Lactobacillus casei (treatment 4), and the composition of the diet with 1% potassium sorbate and 10⁷ CFU/ g Lactobacillus casei (treatment 5).The results showed that the highest final weight, SGR, FCR and PER were observed in the treatment 4 which revealed significant differences with other treatments (P<0.05). However, no significant differences were observed between the different treatments regarding the carcass structure (P>0/05). WBC was significantly higher (P<0.05) in T4 compared with the other groups. No significant difference in the amount of RBC, Hb, HCT, MCV, MCH, MCHC were observed (P>0/05). In addition, the number of intestinal bacteria and lactobacillus showed significant differences among the different treatments. and highest rate was observed in treatment 4 (P<0.05) In total, according to the results and the positive observed effects, the addition compound CFU/ g 107 bacteria (Lactobacillus casei) and 0/5% of potassium sorbate in the diet of rainbow trout diet is recommended.

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So far, the Caspian black-striped pipefish (S. caspius) is the only recorded species of the Syngnathidae in Caspian Sea. In this research, 50 specimens of pipefish were collected from brackish water of Gorgan Bay, and the basic information related to 21 morphometric and 6 meristic characteristics and population dynamic parameters including L-infinity, t-zero , instant growth rate, and condition factor were estimated. Results show the existence of two distinct populations with significant differences in some morphological parameters, especially in eye diameter, snout length, anal and pectoral fins height and mouth height in pipefish inhabiting southeast Caspian Sea. However, there was no significant difference between the two populations in meristic characteristics. Aging using opercula revealed 5 age groups (0+-4+). The maximum total length was observed 144 cm (3+ years) and 149 cm (4+ years) in male and female genus, respectively. Von Bertalanffy model was Lt=177.94 (1-e0.3(t+0.56)) and Lt=153.69 (1-e0.3(t+1.07)) for Caspian population and semi-Black Sea population, respectively. Growth pattern was reported as negative allometric model in two populations. Separation of the studied populations in Gorgan Bay were proved via investigating some biometric parameters of Caspian pipefish using multivariate statistical methods of PCA and DFA. Final identification of species or subspecies needs genetic studies.

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Effects of Dimethoate Pesticide and Bacilar Bio-fertilizer on Some Blood Biochemical Parameters of Common Carp (Cyprinus carpio)
 
Abstract
 
Dimethoate pesticide and bacilar bio-fertilizer are two common inputs widely used in Iranian agriculture which washed by run-off and transmitted to aquatic ecosystems where they can cause biological and physiological problems for aquatic organisms. The objective of this research was to study the combined effects of dimethoate pesticide and bacilar bio-fertilizer on blood biochemical parameters of common carp. To this end, 270 fish were selected and allocated into 9 treatment including: control group, treatment A (0.016 mg/L pesticide), treatment B (0.032 mg/L pesticide), treatment C (0.1 ml/L fertilizer), treatment D (0.2 ml/L fertilizer) and combined treatments AC, AD, BC, BD, in triplicate. Fish were exposed to different concentration of dimethoate pesticide and bacilar fertilizer for 14 days. The blood biochemical parameters including Triglyceride (TG), Cholesterol, Glucose, Protein, Albumin, and Globulin were measured. The amount of TG in treatments A, C and D showed significant increment in comparison with control group. The amount of Cholesterol in treatments A and B had been increased in comparison with control group but in treatment AD had been decreased. The amount of Glucose showed no significant differences in all treated groups in comparison with control group. Protein had been increased in treatments C, D and other combined treatments except AC. The amount of Albumin in all treatments except A had significantly increased. The amount of Globulin in all treatments except B did not have any significant differences with control group. The results of this study revealed that combined treatment of dimethoate and bacilar bio-fertilizer did not showed remarkable differences from their singular treatments and more research with higher concentrations of pollutants are required for better understanding of their interactional effects.
 
Key words: Agricultural pollutants, organophosphate pesticides, physiological parameters, fishes

 

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This study was carried out with the aim of investigating the possibility of separation of Caucasian faeces with the aid of grapefruit traits (Berg, 1916) Knipowitschia caucasica between two areas of Gomishan wetland and Gorgan Bay in the spring of 1395. In this study 120 samples of this species were studied. In this study, the method of analysis of the main components of the possibility of separating the two reserves was studied. The properties studied were separately compared to each other. The traits were standardized before being used by Bagam method. The KMO coefficient was 0.81, indicating the suitability of the decomposition method to be the principal components for examining the possibility of separating the reserves. The output of the experimental model to the main components indicated that there were four factors with special values ​​greater than one for morphometric traits and six factors for relative morphometric characteristics. The results of this study showed that the Caucasian gastropods in these two regions can be divided into two separate reserves despite the presence of partial mixing.

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Selenium is an essential nutrient for physiological function, including immunity, Reproduction and nervous systems. This element as glutathione peroxidase enzyme cofactor, improve fish growth and propagation index via reducing of free radicals. In the present study, the effect of different levels of organic selenium were evaluated on some antioxidant indices, such as total antioxidant capacity (TAC) and malondialdehyde (MDA) and Reproduction indices including, gonadal development, histology evaluation, fertilization rate and survival of the treated fish larva. Adult goldfish were fed with 0 and 0/5 mg of organic selenium (Selplex) per kg food for 8 weeks, and HCG hormone was injected Intraperitoneally to induce the gonadal development in the treated broodstocks. Results showed that the TAC in blood serum treated with selenium broodstocks was increased and MDA levels were also significantly reduced. Histological studies showed selenium treated testicular tissue broodstocks, the level of mature spermatozoa are significantly higher than the control group and in the ovarian tissue, sexual maturation in the control group and treated group were in stage 2 and 5 respectively. In addition, rates of fertilization (%91/17), deformity (%8/45) and survival (%87) in the Selenium treatment compared to the control group showed significant improvement. Therefore, Significantly higher body weight, antioxidant function, gonadal development in the fish treated with 0.5 mg selenium were shown in compare to the control group, to which no organic selenium was fed.

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Today in aquaculture to prevent negative effects of antibiotics The use of alternative, such as probiotics, prebiotics, organic acids, That can have positive effects on fish physiology activities. This study in order to done the synergistic effects of organic acid (potassium sorbate) and probiotic (Lactobacillus casei) in rainbow trout fry (Oncorhynchus mykiss). For this purpose of 360 pieces of rainbow trout with an initial weight (2.45±0.05), at 6 treatments with 3 replication include: Commercial diet (control), diet 10⁷ CFU/g probiotic (Lactobacillus casei) (treatment 1), a diet containing 0.5% of potassium sorbate (treatment 2), a diet containing 1% potassium sorbate (treatment 3), The composition of the diet with %0/5 of potassium sorbate and 10⁷ CFU/g probiotic (L. casei) (treatment 4) and the composition of the diet containing %1 potassium sorbate and 10⁷ CFU/g probiotic (L. casei) (treatment 5) was carried out. Feeding in two stages and trial period of 60 days. Sampling of fish To search Digestive enzymes, intestinal Histomorphology and juveniles resistance against pathogenic bacteria (Yersinia ruckeri), was conducted At the end of the experiment. The results showed, The activity of digestive enzymes was significant in the different treatments (P<0.05). Also Survey intestinal Histomorphology showed no significant difference In different treatments (P>0.05). Results of the test resistance to pathogenic bacteria (Y. Ruckeri) showed That mortality rate during the 14 days was significant among treatments (P<0.05). In total, according to the results of this study, suggested Add, combine %0/5  potassium sorbate and 10⁷ CFU / g probiotic (L. casei) in diets for rainbow trout.

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Gorgan Bay and the southeastern coasts of the Caspian Sea in the Golestan Province are important biological and fisheries areas., while in recent years, they have been heavily contaminated. In present study, the dynamic of fishes, using stable nitrogen and carbon isotopes was evaluated to determine the diet and its trophic status, which can accurately chart the ecosystem's biological conditions. Accordingly, in September-October 2015 at 5 ecological stations, sampling of prephytones, macrophytes, macro invertebrates and fish, were taken and dominant species were subjected to isotope analyzes using the EA-IRMS device. The results of the nitrogen-15 and carbon-13 isotopes indicate an imbalance in ecosystem conditions that alters the diet of the organisms and reduces the efficiency of the food web. The main factors of pressure on the ecosystem, the closure of the main channels of the sea to the bay, the entry of various pollutants into the ecosystem and weak physiography of Gorgan Bay, were determined.

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The present study was performed to measure heavy metals (Pb, Zn, Cd and Cu) in the muscle, liver, gonad, intestine and digestive parasites of Pike (Esox lucius) in Anzali wetland. For this purpose, 90 fish Pike were sampled from Anzali wetland during 2020 and in the reproductive season (winter). During the experiment, total length, fork length, standard length and total weight were measured. The age and sex of the fish were also determined. After emptying the viscera, muscle tissue, gonads, intestines, liver, and parasites were isolated. Then, chemical digestion and metal analysis were performed. The results showed that liver (especially copper: 220.270 mg / kg and zinc: 99.199 mg / kg) and intestine (especially copper: 650.1 mg / kg and zinc: 605,014 mg / kg) had the highest levels of metals. It was heavy in duck fish (P<0.05). The study showed that there was no significant difference between males and females in most cases (P>0.05). Also, middle-aged fish had higher amounts of heavy metals (P<0.05). However, this was not accurate and in many cases the same age did not have a significant effect (P>0.05). In addition, high amounts of heavy metal were observed in fish parasites (P<0.05). Parasites appear to act as absorbers of heavy metals or transport them from the outside environment to the fish body. In terms of heavy metals, the amount of lead (average of total organs: 0.005 mg / kg) and cadmium (average of total organs: 0.0105 mg / kg) was lower than the other two heavy metals. Copper, lead, and cadmium levels were in most cases below the WHO standards. Since the amount of heavy metals in the muscle and even the gills of duckfish (in terms of food) is much less than the allowable limit, it can be said that there is no problem in terms of human consumption and to some extent the presence of these elements in The fish ignored. But oral consumption of the liver and intestines has the highest risk among the organs. In addition, the oral consumption of two different species of duck fish does not differ in the rate of absorption of heavy metals and its effect on humans.

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The aim of this study was to investigate the effect of adding lactic acid to the diet of rainbow trout on growth indices, activity of digestive enzymes and microbial flora of the fish gastrointestinal tract. For this purpose, 4 diets containing 0, 5, 10 and 20 g of lactic acid per kg of diet were made and each diet was offered to fish in three replications for 8 weeks. The results showed that there was no significant difference in growth and survival indices between different treatments (P> 0.05). The highest activity of gastric pepsin enzyme was observed at the level of 10 and 20 g of lactic acid in the diet (P <0.05). The highest alpha-amylase activity was observed at the level of 10 g of lactic acid in the diet (P <0.05). Lipase activity in the control treatment and 10 g of lactic acid in the diet was similar and significantly higher than the treatments of 5 and 20 g of lactic acid in the diet (P <0.05). Intestinal protease activity in treatments of 5 and 10 g of lactic acid in the diet was higher than the control treatment and the highest activity was related to 10 g of lactic acid (P <0.05). Treatment of 20 g of lactic acid in the diet had lower protease activity than the control treatment (P <0.05). The highest number of total intestinal bacteria was observed at the level of 5 and 10 g of lactic acid in the diet (P <0.05). The number of intestinal lactic acid bacteria in lactic acid treatments was significantly higher than the control treatment (P <0.05). The highest number of lactic acid bacteria was observed in the treatment of 10 g of lactic acid in the diet (P <0.05). According to the results, the addition of lactic acid to the rainbow trout diet has no effect on growth, although it does increase the activity of digestive enzymes. However, adding 10 g / kg of lactic acid leads to an increase in lactic acid bacteria in the gut of the fish.
 

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Synbiotics and rare elements such as selenium strengthen non-specific defense in aquaculture industry and improve digestion and absorption of diets. The aim of this research was to determine the effect of diet supplemented with organic selenium (Selenomethionine) and synbiotic Dipro+ separately and combined on digestive enzyme activities, intestinal bacterial flora and intestinal histology in Salmo caspius. In this research, 540 pieces of Caspian Sea with an average weight of 66.34 ± 1.45 grams were prepared. After adapting to the experimental conditions, the fish were randomly distributed in 27 fish ponds. This experiment was conducted in the form of a completely randomized design under 8 experimental treatments and a control group (each with 3 repetitions) for 8 weeks. Experimental treatments include: 2 grams of synbiotics per kilogram of diet (treatment 1), 3 grams of synbiotics per kilogram of diet (treatment 2), 2 milligrams of organic selenium per kilogram of diet (treatment 3), 4 milligrams of synbiotics biotic per kg of diet (treatment 4), 2 grams of synbiotic and 2 mg of organic selenium per kg of diet (treatment 5), 2 grams of synbiotic and 4 mg of organic selenium per kg of diet (treatment 6), 3 gram of synbiotic and 2 mg of organic selenium per kg of diet (treatment 7), 3 grams of synbiotic and 4 mg of organic selenium per kg of diet (treatment 8). Then, at the end of the experiment, in order to examine digestive enzyme activities, blood was taken with the an insulin syringe from the caudal artery or vena cava or by cutting the caudal stem. Also, in order to measure intestinal tissue changes, samples were taken from intestine. The highest amount of digestive enzymes, including: amylase, lipase and protease, was recorded in treatment 1, that is, the group fed with 2 grams of synbiotic dipro⁺, which was significantly different from the control group (P < 0.05). The lowest amount of lactic acid bacteria (LAB) and the total number of intestinal bacteria (TVC) were significantly present in the control group (P < 0.05). The results showed that there was a significant difference between the intestinal tissue indices in the groups fed with nutritional supplements combined and separately with the control group. Altogether, the results showed that the combined use of synbiotic dipro⁺ and organic selenium could reduce tissue damage and is recommended as a supplement in the diet of Salmo caspius .