نشریه پژوهش های ماهی شناسی کاربردی
سال هشتم شماره 2 (تابستان 1399)

Some 78 specimencs of trout barb (Capoeta trutta) from four rivers of Bushehr Basin were caught by seine net to compare their morphology using geometric morphometrics. The specimens after anestethizing in 1% clove oil, were fixed in bufferd 10% formalin and transferred to the Isfahan University of Technology Ichthyology Museum for further studies. Geometric morphometric method were applied to accomplish the biometric studies. For statistical analysis, Canonical Variable Analysis (CVA), Principle Component Analysis (PCA), Cluster Analysis (CA) and Discriminant Function Analysis (DFA) were employed. The PCA, CVA and CA showed differences between KheirAbad and Fahlian populations from Bushehr Basin in geometric morphometrics. This result showed that geometric morphometric methods could separate many populations of Bushehr Basin from each other. However, for more details, molecular studies are needed.

Fish sampling was conducted to evaluate the species diversity of fish in 4 stations in Sanandaj Azad dam ecosystem seasonally from summer of 2017 to spring of 2018. A total of 1057 fish were caught in 12 species, of which more than 80% were caught in the lake behind the dam. The Cyprinidae family had 11 species with the most species diversity and only Sasanidus kermanshahensis belonged to the Noemachilidae family. There was no significant difference between Shannon species diversity in the lake behind the dam (with a mean of 1.11 ± 0.32) and Komaci River (P> 0.05), and in summer with other seasons there was a significant difference (P <0.05). The size and weight of the population living in the lake habitat behind the dam were significantly higher than the population living in the river habitat (P <0.05). Among the identified fish species, 5 species Carrasius auratus, Cyprinus carpio, Hemiculter leucisculus, Hypophthalmicthys molitrix and Pseudorasbora parva are exotic species. Among the influences of exotic fish is its competition with native fish for food, and this will have a significant impact on the species diversity of the fish, population dynamics and fish populations. Also Sasanidus kermanshahensis is an endemic species for Iran, which is very important for protection. Considering the importance of endemic species and the presence of a considerable number of exotic fish species in the Azad dam ecosystem, the results of this study are of considerable importance.

Knowledge of biological requirements of aquatic organisms in perennial rivers is necessary for protection of biological diversity in riverine ecosystems. Habitat knowledge includes using models for estimating specific properties from physical structure of rivers by simple and accurate methods. Fuzzy regression model was investigated for two common endemic and benthic fishes, Paracobitis hircanica and Neogobius fluviatilis, in Zarin Gol River of northern Iran. P.hircanica and N.fluviatilis overlapped in mesohabitat use, both fish preferred riffle to pools. Further analyses based on stepwise multiple regressions showed that fish abundance was significantly correlated with riparian vegetation and substrate for P.hircanica, but correlated with water depth, stream width, velocity, and discharge for N.fluviatilis. The obtained results showed that fuzzy regression can be an appropriate complementary or alternative method for statistical regression when the relationship between the variables is vague or there are errors due to vagueness in regression equation structure. The result recommends that the various substratum compositions may have accounted for the co-existence of these two benthic fishes. It would also provide important information for habitat management and ecological engineering of mountain rivers in Iran.

Morphological similarities of the populations and species of the genus Ponticola in the southern Caspian Sea make their identification difficult based on the provided keys. Molecular markers are used as a supplementary tools to better understanding of the fishes’ taxonomic statues. This study was conducted to understand taxonomic statues of gobiids from 6 rivers (Siah, Zaringol, Babol, Tajan, Sefid vis. Bijar and Kisum populations, and Kelsian) in Southern Caspian Sea basin based on DNA barcoding using mitochondrial COI gene by reconstructing phylogenetic tree based on ML and BI methods and drawing haplotype network and assessment of the geographic and genetic distances. The results show a mean genetic distance (K2P) of 0.69-1.68 between the studied populations that is too low for considering them as distinct species based on the genetic criteria. Also, BI and ML cladograms and haplotype network showed all populations are haplotypes of P. gorlap.

The purpose of this study was to investigate the effects of aliphatic sodium butyrate on some blood parameters and growth factors in carp fingerling with an average weight of 10 g. This experiment was conducted for 8 weeks by using four different diets with three replications including: control (without supplement) and three levels of sodium butyrate (0.25, 0.5 and 1%). Feeding was performed for 2 months daily 2 times 3% of the body weight of the fish and were taken biometric 2 times in a month. At the end, blood parameters (including the number of red blood cells, white blood cell count and fractional count, hematocrit and hemoglobin), and growth factors (final weight, specific growth factor, feed conversion ratio and consumable food intake) were evaluated between the experimental  groups. This experiment was done in a completely randomized design. Data analysis was performed using SPSS and Excel software packages. Finally, there was no significant difference in final weight, specific growth factor, feed conversion ratio and food intake between experimental groups. The results of this study showed that sodium butyrate had no effect on the number of red blood cells, hematocrit, hemoglobin, mean corpuscular vein (MCV), moderate hemoglobin (MCH), and moderate hemoglobin concentration (MCHC). There was also a significant difference between the levels of white blood cells between the levels of 0.25% and 1% in the control group. There was no significant difference between the levels of 0.5% and the control group. The results of this experiment showed that the addition of sodium butyrate to carp diet did not affect the growth and blood factors of this fish, but the white blood cell count decreased by 0.25% and 1%.

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.

In recent years, drugs have been identified as newly emerging and threatening the aquatic and terrestrial environments. Accordingly, in this study, the effect of indomethacin on oxidative stress in Cyprinus carpio was investigated. In order to determine the LC50, the fishes were exposed to various concentrations of indomethacin and daily losses were recorded during hours. In the next step, the fishes were exposed to various concentrations of indomethacin in five treatments including T1 (control), T2 (0.01 mg), T3 (0.02 mg), T4 (0.05 mg), T5 (0.1 mg) for 28 days. At the end of the experiment, antioxidant enzymes such as catalase (CAT), glutathione peroxidase (GPX) and malondialdehyde (MDA) were measured in the liver and gill tissues treated fishes.the lethal toxicity (LC50) of indomethacin was obtained for carp (328.49 mg/l). GPX enzyme activity in gill and liver tissue in all treatments increased significantly in compared to the control group (p<0.05). MDA levels in liver tissue in T4 and T5 groups and gill tissue in T3 and T4 groups showed a significant increase in compared to the control group (p<0.05). Also, CAT activity in liver and gill tissue in T4 and T5 groups was increased significantly in compared to the control group (p<0.05).The results of this study demonstrated that presence indomethacin in an aqueous environment can influence the antioxidant status and health of the fishes.

This study was conducted to survey of distribution and abundance of cutlassfish (Trichiurus lepturus, Linnaeus 1758) as target species between the fishing grounds of Bushehr and Hormozgan provinces. Sampling operations were carried out during the summer season in Bushehr province and autumn season in Hormozgan province in 2013. The fishing operation was done using commercial trawler vessel with a length of 27 m, the width of 7.2 m during 73 times net hauling in the fishing seasons. The used net in this research was a mid-water trawl net with a polyethylene yarn and mesh size of 75 mm (stretched) in the codend. The highest length frequency of cutlassfish was observed in the length range of 84-92 cm and the least length frequency was in the length range of 28-36 cm. The biomass and mean CPUA in Bushehr were 17169.55 tons and 8624.42 ± 1076.58 (kg nm-2) and in Hormozgan were 7425.804 tons and 8105.74 ± 1529.87 (kg nm-2), respectively. Also based on depicted maps by GIS software and CPUA index, Most densities of trapped cutlassfish in Hormozgan fishing grounds were around Hengam and Greater Tomb islands, and in Bushehr (Motaf area), there was a horizontal distribution in the western waters of this province.

The aim of this study was to evaluate the effects of silver nanoparticles (AgNPs) on taste feeding behavior of Persian sturgeon (Acipenser persicus) juveniles, including taste palatability index, fishing efficiency and the number of consumed pellets, to some amino acids. Taste Feeding behavior was investigated following exposure to 0.01, 0.005 and 0.001 mg L-1 AgNPs for 21 (each group with 3 replicates and each replicate with 7 fishes). Then, the feeding behavior of fishes was investigated by using of experimental pellets containing chromium oxide 0.3%, agar 2% and amino acids in question (Serine, Arginine, Cysteine, Tyrosine, Glutamic Acid, and Aspartic Acid).  The results showed that the taste palatability index was negative for all amino acids and pellets containing the Chironomidae larvae extract in concentrations of 0.01, 0.005 mg L-1 AgNPs. Also, the number of consumed pellets was significantly lower than the control for all amino acids (pFurthermore, AgNPs at all concentrations significantly reduced the fishing efficiency in amino acids of Arginine, Cysteine and Tyrosine. Considering that in this study the lowest Concentration of AgNPs also had a negative effect on taste feeding behavior of Persian sturgeon, therefore, it is recommended that the amount of AgNPs is less than 0.001 mg L-1 before release to aquatic environments.