نشریه پژوهش های ماهی شناسی کاربردی
سال دوازدهم شماره 1 (بهار 1403)

The Persian Gulf and the Oman Sea contain a variety of aquatic species. Among which, scomberoides commersonnianus fishes are important that has increased its catch in recent years. In this research, the demographic characteristics of Talang queenfish fish were estimated by collecting data from April 2022 to March 2023 from 4 catchment areas including Pezam, Kanarak, Breis and Pasbandar on the coasts of Sistan and Baluchistan province. In this study, more than 1900 fish at the research stations were biometric and the growth parameters were infinite length of L∞ = 137 cm, growth factor K = 0.54 (yr-1), natural mortality M= 0.52(yr-1), mortality and mortality (yr-1), F = 2.21, total mortality (yr-1), Z = 2.73 and exploitation coefficient (yr-1), E = 0.8, and the time zero was -0.19. According to the calculations, the average initial biomass was obtained 98 (56-173) thousand tons, the average current biomass 44(20-58) thousand, the average maximum sustainable yield (MSY) around 14 (8-22) thousand tons. The ratio of current fishing mortality to maximum sustainable yield (F/FMSY) was showed greater than one (1.33) and the ratio of current biomass to maximum sustainable yield (B/BMSY) is less than one (0.9). This study shows that the annual harvest of Talang queenfish stock has reached its maximum and any increase in fishing effort will affect this fish stock and will reduce the amount of exploitation in the long run.

In the issue of aquatic management and assessment of freshwater fish species, it is important to examine habitat preference and habitat suitability indices, because the presence of many species in an aquatic ecosystem indicates the suitable conditions of their habitat. Therefore, this study was carried out to investigate and preference habitat of Oxynoemacheilus zarzianus in the Sirvan River. Sampling was done from different parts of the river (regarding depth, width and etc.)  in 7 stations each with 3 repetitions and a total of 21 stations. Sampling was performed along 30 m at each station against the direction of the river velocity, from the downstream of the river to the upstream. Ten environmental factors including pH, temperature, total dissolved solids, electrical conductivity, Altitude, depth, river width, velocity, and bed slope were measured. The results showed that the highest and lowest total SI values ​​for studied species were obtained for the altitude (0.237) and river width (0.1), respectively. The results showed that the highest abundance and presence of O. zarzianus were in places with gravel beds, which probably preferred these places to avoid predators. The value of the total suitability index also showed that this river is not a suitable habitat for Zarzian loach. Therefore, it is necessary to consider special management measures for this species, whose presence has been reported in this river recently.

The aim of this study was to investigate the effect of in fall and winter on the hematological and serum biochemical factors of 3-4 years old great sturgeon in the penclture ) located in the Gorgan Bay (Caspian sea) and processing sturgeon center of Marjani for 6 months.  Huso huso individuals were anesthetized withclove powderand 5 mL of bloodwas sampling from a total of 15 great sturgeon specimens were apparentlyhealthy by caudal venous puncture each of the examined panes (3 pins)in different seasons.Blood was analyzed with routine method and standard formulas used in fish hematology. the results showed thatthere are no any differences between the mean corpuscular volume, cortisol levels and activity of Alanine aminotransferase enzyme in the different season(p>0.05).But, by examining other parameters, the highest WBCs number, Activity of aspartate aminotransferase and alkaline phosphatase enzymes in summer, the highest RBCs number, hematocrit concentration, total serum protein in spring, the highesthemoglobin concentration, the mean corpuscular hemoglobinand themean corpuscular hemoglobin concentration in autumn and the highest glucose levels in winter were observed, which were significantly increased in comparison with other seasons (p<0.05). Overally, based on these results, it can be rectified that temperature changes as a result of season transition may have an important role on Blood factors of Huso huso. As with the same ecological conditions, with changing the temperature of the environment, we will see different changes in the blood factorsin the Beluga.

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 .

The aim of this research is to investigate the effects of different levels of olive leaf polyphenol (POL) on salmon. The rainbow is Oncorhynchus mykiss. Number of 120 pieces of fish with an average weight of 6.5 ± 0.1 grams were randomly divided into four treatments with three replications in 100 liter storage tanks and with four diets containing zero, 0.5, 1 and 2 grams (POL) per kilogram. The food was fed for 8 weeks. At the end of the period, growth factors, non-specific immune indices of mucus and serum and the relative expression of immune genes were investigated. Investigation of serum safety indicators, blood sampling from the caudal stem of the treatments was done completely randomly. To measure mucus safety indicators, sampling and collection of mucus from all treatments was done completely randomly. Relative expression of immune genes was investigated from sampled intestinal tissues. The obtained results showed the improvement of growth indices in fish fed with three different levels (POL). In terms of non-specific immunity, the results showed an increase in total serum and mucus immunoglobulin in the groups fed with a diet containing 1, 2 g/kg (POL) (P<0.05). The amount of lysozyme activity of total serum and mucus was also affected by (POL) and fish fed with 1 and 2 grams of (POL) showed a significant increase (P<0.05). The relative expression of the immune gene was also affected by feeding with the above supplement in the mentioned treatments (P<0.05). The highest relative expression of the interleukin gene was obtained in the treatment of 2 g/kg and tumor necrosis factor in the treatment of 1 g/kg (POL). Consumption of 2 g/kg olive leaf polyphenol supplement can have a favorable effect on the growth and rearing quality of trout fry.

AbstractThe study investigated the effects of substituting fishmeal with different levels of hydrolyzed protein on the serum biochemical composition and immune system of beluga (Huso huso) fry over a 48-day period. A total of 750 fish were randomly assigned to five groups: a control group (no hydrolyzed protein), three groups with varying levels of hydrolyzed protein (2.75%, 5.5%, and 8.25%), and a positive control group (commercial feed). The study found significant differences in glucose levels among the groups (P<0.05), with the control group having the highest glucose level. Treatment 2 had the highest total protein and lipid levels, which significantly differed from the other groups (P<0.05).  Liver enzyme levels (ALT, AST and ALP) did not vary significantly among the groups (P>0.05).  There were no significant differences in cholesterol levels (P>0.05). Regarding immune factors, treatment 2 exhibited significantly higher total immunoglobulin levels compared to all other groups except for treatment 3 (P<0.05). Lysozyme levels did not differ significantly between the control group and treatments 1, 3, and 4 (P>0.05); however, treatment 2 displayed the highest level. IgM and ACH50 activity did not differ significantly across all groups (P>0.05). In conclusion, replacing fishmeal with hydrolyzed protein at a concentration of 2.75% to 5.5% improved performance in blood biochemical and immune parameters of beluga fry when compared to the control group.

The aim of this study was to determine the optimal salinity for rearing the juveniles of Starry Sturgeon (Acipenser stellatus) in enclosed environments. Sturgeon with an average initial weight of 54.11 ± 1.54 g were raised in 500-liter fiberglass tanks (average temperature 22.58 ± 0.14 °C)in a control group (freshwater) and two treatment groups (6  and 12 ppt) in 3 replicates for 60 days. They were fed with commercial feed (Faradaneh) twice a day. At the end of the rearing period, specific growth rate (SGR), weight gain (WG), condition factor (CF) and hepatosomatic index (HIS) in experimental fish (12 ppt) were significantly elevated compared to control fish (p≤ 0.05). Food conversion ratio (FCR), on the other hand, was significantly reduced in the experimental fish (p≤ 0.05). The survival rate of fish was 100%. Intestinal villi length and internal space were significantly elevated and reduced in 12 ppt salinity, respectively (p≤ 0.05). The results suggest that the optimal salinity at this point of Starry Sturgeon life is the Caspian Sea water salinity (12 ppt) which provides the conditions for introducing this species as a suitable species for rearing in enclosed environments in natural water resources. Considering that A. stellatus lives in waters with diverse salinities at different stages of its life, it is important to know the appropriate weight and salinity for releasing in order to increase the percentage of survival and improve growth.

In order to investigate the possibilities and solve the obstacles and problems of ornamental fish farmers, information was collected online by designing an electronic questionnaire. The results of the 66 investigated farms in the country showed that, on average, 14 species of freshwater ornamental fish are produced in each farm, and 10% of the farms produced more than 25 freshwater species in each farm, of which 9 species were oviparous—according to Friedman's test, Biomare, Tetra, and Tropical food brands had the highest demand and level of satisfaction among imported brands in Iran, respectively. The most important live food consumed in the ornamental fish industry is Artemia, which was reported as one of the most important challenges of Artemia in Iran, its high price with 66.2% and low hatch percentage with 58.5%. About half of the farmers did not have communication with universities and the Iranian Fisheries Organization to solve their problems. One of the reasons for visiting the university was to solve the problem of fish diseases, to increase the reproduction rate, and then to improve the quality of water and wastewater. For disease problems, the main priority of farmers was to consult with other farmers and refer to literature. Based on the results of the chi-square test, water restrictions, and water quality control, the quality of Iranian feed brands, the hire of experts and skilled workers, the lack of credit aids and bank facilities, the lack of suitable feed, and the final price, the lack of formation of a trade :union: council, the increase in the price of inputs and currency, and the lack of space for fish farming has greatly affected this industry in Iran.