مجله علمی شیلات ایران
سال سی و دوم شماره 3 (پیاپی 137، امرداد و شهریور 1402)

The Sefidroud River is the largest river in the north of Iran and has a special importance in the survival of Caspian anadromous fish. In this study, the biodiversity and abundance of fish were investigated in eight points of the Sefidroud River and one point on the sea coast from March 2022 to January 2023. There were identified a total of 40 species of fish from various ecological groups; riverine (26 species), migratory (6 species), and estuarine-marine (8 species). The highest and the lowest number of species were observed in the mid-region of the river and the marine area with 21 and 17 species, respectively. The spatial ecological niche was observed for some species such as three Gobiidae species Caspian goby (Neogobius caspius), Caucasian dwarf goby (Knipowitschia caucasica), and Iranian Goby (Ponticola iranicus) occupied the sea coast, the estuary, and the upstream area, respectively. Mugilidae species were also seen up to 10 km from the sea. The eggs and larvae of anadromous fish were observed in the highest station. Kutum (Rutilus frisii) and Danube bleak (Alburnus chalcoides) fry fish had the highest abundance among the identified species of with 222 and 92 number/200m2, respectively. Bream (Vimba persa), Leaping mullet (Chelon saliens), European bitterling (Rhodeus amarus), Sanias spined loach (Cobitis saniae), North Caucasian bleak (Alburnus hohenackeri) had moderate frequency between 27 to 59 number/200m2 and the abundant of other species was low between 0.014 to19 number/200m2. The lowest Shannon's diversity index was in the furthest distance from the Caspian with value 1.03, while the highest value, with significantly difference p<0.05, was observed in 5 km to the sea with value 1.6  Also, the highest and lowest values ​​of the index were observed in November 2022 and January 2023, respectively.

In this study, the effects of dietary extruded oak acorn flour on growth performance and carcass composition of common carp were studied. Four diets were investigated in a completely randomized design included 1- extruded wheat flour (17%), 2- non-extruded wheat flour (5%) and extruded wheat flour (12%), 3- non-extruded acorn flour (5%) and extruded wheat flour (12%), and 4- extruded acorn flour (5%) and extruded wheat flour (12%). The culture was started in round tanks with a volume of 250 liters and a density of 15 fish in each tank with an initial weight of 5.4 g in three replicates. After 4 weeks, no significant difference was observed in the weight and total length of fish, but after 8 weeks, the highest weight and total length were observed in the fish fed diet 4. Extrusion of acorn flour had a significant positive effect on the weight and total length of fish, but extrusion of wheat flour did not have such an effect. Diets had no significant effect on the condition factor, specific growth rate, feed intake, feed conversion ratio, protein efficiency ratio, lipid efficiency ratio, protein retention, carcass moisture content and survival rate. Extrusion of wheat flour and acorn flour had significant positive effects on lipid retention and these effects were much greater when the extruded acorn flour was consumed. The levels of carcass protein and ash were significantly reduced by feeding on non-extruded acorn flour. Consumption of non-extruded wheat flour or acorn flour caused a significant reduction in carcass lipid and this reduction was more severe when using non-extruded acorn flour. Overall after peeling the oak acorn, its flour can be used instead of wheat flour at the level of 5% of the extruded diet for common carp.

Fish epidermal mucus protein extraction for bioassay-guided screening is challenging and variable. In this study, four different protein extraction methods, including acetone, trichloroacetic acid (TCA)-acetone, methanol, and solid-phase extraction (SPE), were investigated to study their efficiency in ultrafiltration and to obtain the appropriate peaks in HPLC to measure biological activities. The presented data shows that the solid phase extraction method is better than the other three tested methods in quantity (total protein yield) and quality (protein profile observed in SDS-PAGE) of proteins and peptides from the epidermal mucus of Caspian monkey goby. On the other hand, due to the epidermal mucus hydrophobic nature, all three extraction methods including acetone, (TCA)-acetone and methanol led to the irreversible proteins aggregation, makes ultrafiltration, HPLC, and consequently bioactivity screening impossible. In this study, the highest amount of protein (4.676 μg/ml) (P<0.01) and the best protein profile (13 bands) were related to solid phase extraction. Also, this method simultaneously leads to the extraction, concentration, and initial purification of the samples and therefore improves the efficiency ultrafiltration and HPLC. Thus, we introduce this method for the isolation of active proteins and peptides from various complex biological samples, including fish epidermal mucus.

Three research cruises were carried out using Ferdous 1 research vessel equipped with a bottom trawl net in the waters of Khuzestan province during 2018-2021 (except for 2020) to monitor the aquatic demersal resources of the northwestern waters of the Persian Gulf. During this three years’ survey, a total of 51 stations were randomly selected for sampling at 10-50 m depths for further Biomass and Catch Per Unit of Area (CPUA) estimation by Swept Area Method. Four important and commercial species including silver pomfret (Pampus argenteus), tiger-tooth croaker (Otolithes ruber), Sobaity seabream (Sparidentex hasta) and orange-spotted grouper (Epinephelus coioides) were selected. The estimated biomass for years 2018, 2019 and 2020 were 1.1,0.0 and 7.1 tons for silver pomfret; 46.8, 23.3 and 57.6 tons for tiger-tooth croaker; 59.8, 76.7 and 137.3 tons for sobaity seabream and 30.3, 3.1 and 0.0 tons for orange-spotted grouper, respectively. During this period, silver pomfret with 0.01% (in 2018), Sobaity seabream with 3.37% (in 2021) had the minimum and maximum ratio of total biomass, respectively. From point of fisheries management, the following recommendations are proposed:- Prevent any increase in catch per unit of effort (such as number of fishing vessels)          
- Control and supervise the fishing activities, fishing grounds and prohibit the illegal fishing

In this research, the effect of selenium nanoparticles on the performance of antioxidant enzymes, including superoxide dismutar (SOD), glutathione peroxidase (GPx), malondialdehyde (MDA), and catalase (CAT) levels, and male reproductive egg ions of rainbow trout was investigated. The number of 144 fertile pieces of 4-year-old Iranian females was divided into four treatments in three replications. The treatments were fed with diet containing zero (control), 0.5, 1 and 2 mg of selenium nanoparticles per kg of diet for 60 days until egg maturation. Based on the results of the research, the values of SOD, CAT, and MDA have shown significant differences in the eggs from different treatments (p<0.05). The lowest level of SOD enzyme and the highest level of CAT enzyme were observed in the control treatment, which showed a significant difference with other treatments. There was no significant difference in the amount of GPx enzyme between different treatments (p>05). The amount of MDA enzyme showed a significant difference among the treatments, while the control group had the highest level of 363±16.8 mmol/ml and the fish fed with selenium nanoparticles at 2 mg/kg had the lowest level of 181±9.5 mmol/ml Comparing the average amounts of magnesium and calcium among different treatments showed a significant increase in the amounts of the mentioned ions in the treatment fed with selenium nanoparticles at the rate of 2 mg/kg of food compared to other treatments (p<0.05). In general, considering the decreasing role of antioxidant enzymes and its increasing role in the amounts of magnesium and calcium inorganic compounds in the eggs of mothers fed with more selenium nanoparticles, this essential micronutrient can be used as It should be considered as a suitable candidate for further research in order to improve the quality of spawning eggs of female rainbow trout by adding to the diet.

Probiotics are non-pathogenic microorganisms that have beneficial effects on living organisms. Also, zinc as a micronutrient has useful properties and is essential for the body of living organisms. Probiotics and zinc can have a positive role in the health of living organisms with their synergistic effects. Small amounts of micronutrients are needed for the growth and development of living organisms, but large amounts of them can be toxic. Micronutrients are found in nature in two forms, inorganic and organic, which the organic form is less toxic. Bacteria and fungi are among the microorganisms that can convert minerals into organic forms and reduce their toxicity. Therefore, in this study, two probiotics, Lactobacillus acidophilus and Candida utilis, were selected and their ability to absorb and accumulate mineral zinc as well as the growth rate of the microorganisms were investigated. For this purpose, 9 different concentrations of zinc sulfate including 0.05, 0.2, 15, 10, 5, 25, 50, 75, and 100 mmol/l were used. Based on the results, the growth inhibition of L. acidophilus and C. utilis probiotics was obtained at 100 and above 50 mmol/L, respectively. The highest and lowest amounts of zinc absorption in L. acidophilus were 2364 and 498.8 ppm, respectively, and in C. utilis were 41830 and 13174 ppm, respectively. Based on the findings of the present study, it can be concluded that each of these two probiotics has specific capacities in zinc absorption and tolerance based on their cellular structure. The reason for that can be in the mechanism and mode of action and intracellular mechanisms and bacteria have a lower absorption rate than yeast due to the presence of a cell wall. Therefore, the selected bacteria and yeast can absorb zinc and they have various applications in the food and drug industry as a zinc-enriched probiotics.

The aquaculture industry is one of the most important sectors of food production and protein supply and creating food security needed by society. This study aimed to determine and identify the drivers that affect the future of the farming shrimp industry in Hormozgan province in the horizon of 1420 and then determine the importance and priority of each of the identified drivers. To achieve this goal, with a comprehensive review of research literature and upstream documents, 30 propellants were identified and provided to experts, and finally, 23 propellants were selected as key propellants affecting the farming shrimp industry in Hormozgan province. Then, the selected key drivers from the previous stage were provided to the experts in the form of Mikmak questionnaire. The average of their opinions in Mikmak software was analyzed and the direct and indirect effects of the drivers were evaluated, and finally, according to the ranking of the drivers by the software, 10 drivers Selected as key drivers for the farming shrimp industry in Hormozgan province, all 10 drivers were repeated in direct and indirect effects, including 1. infrastructure and equipment; 2. Producer supply; 3. New technologies of shrimp industry; 4. Labor training; 5. Shrimp diseases; 6. Shrimp feed quality; 7. Biosafety and health conditions; 8. Production costs; 9. Research and development in the shrimp industry and 10. Farm monitoring.

Infectious Pancreatic Necrosis (IPN) is an acute and highly transmissible viral disease in fish. So far, this virus has been identified in different species of fish, but this disease is more severe in the Salmonidae family and causes an acute systemic disease with high mortality, especially in fry and juveniles, hence it is an important economic disease in the Salmonidae farming industry. The causative agent of infectious necrosis pancreas is a virus from the Birnaviridae family, the genus Aquabirnavirus (Aquabirnavirus) without an envelope with a thickness of about 65 nm, which has a double-stranded RNA genome, and serologically, they are divided into two groups, A and B. IPNV is a very resistant virus that has little sensitivity to desiccation and UV rays and can survive in a wide range of salinity and temperature. There are a variety of transmission routes for IPNV, adult fish are carriers of the disease after recovery and can transmit the virus vertically (in eggs) and horizontally (through contaminated feces), the disease can also be transmitted through contaminated water, blood-sucking parasites, Contaminated equipment and fish-eating birds are also transported. Considering that a commercial vaccine with high efficiency and effectiveness for this disease has not been developed yet, familiarity with the characteristics of this disease, its transmission and its spread methods can play an effective role in preventing and reducing the incidence and casualties caused by this disease and in reducing economy loses that caused by this global disease could be useful and effective in the fields of aquaculture in the country.

This study focused on the changes in the phytoplankton community of the southern Caspian Sea with an emphasis on the climate change effect. The present study was conducted in the Anzali coast at 10 m depth in May 2023. A total of 33 genera and species were identified from the phyla of Ochrophyta, Chlorophyta, Cyanobacteria, and Myzozoa. The total phytoplankton abundance was measured 135,000±53.000 cells/l. Among the phytoplankton taxa, Ochrophyta had the highest abundance about 99,900±63,000 cells/l. These findings showed an increase in the abundance of phytoplankton in 2023 was 7-fold more than in 2008. The non-native phytoplankton, Dinophysis acuminata from Myzozoa phylum was recorded in the Caspian Sea for the first time. The abundance of D. acuminate was 1620 ± 730 cells/l and the size of the phytoplankton was 30 µm. Probably increase in salinity (13 psu) and increase in sea surface temperature (Climate change) of the Caspian Sea caused the appearance of D. acuminate species.

The fortification of food products with fish meat, which contains essential amino acids and unsaturated fatty acids, can increase the nutritional value of the basic products. On this basis, in the present study, Fatir bread was fortified with the meat of two fish species and then its nutritional value and quality attributes were evaluated. Different concentrations of rainbow trout and silver carp meat were added to the Fatir bread. Proximate composition, chemical, microbial, textural, sensory, and color properties of prepared breads were measured during the refrigeration storage (4°C) for 28 days. The results showed that the protein, lipid, and moisture content of fortified breads were higher than the control bread at first (day 1) and end of the storage period (day 28). Furthermore, the fortified Fatir breads had higher TVB-N, peroxide value, and total bacteria count than control breads during the storage period. In terms of flavor index, the control and fortified Fatir breads were acceptable until 28 and 15 days, respectively. Based on the obtained results, it can be concluded that the nutritional value of the fortified Fatir breads was higher than the control Fatir bread, but their sensory acceptance and shelf life were lower.