JOURNAL OF APPLIED ICHTHYOLOGICAL RESEARCH
Year:2020 | Volume:8 | Issue:2|Papers Count:10

Seventy-eight specimens of trout barb (C. mondica) were captured from four rivers of the Bushehr Basin by seine net for geometric morphometric analysis. After anesthetizing of animal in 1% clove oil, samples were fixed in 10% neutral buffered formalin and transferred to the Isfahan University of Technology Ichthyology Museum for further studies. Geometric morphometric methods were applied to accomplish biometric studies. For statistical analysis, canonical variable analysis (CVA), principle component analysis (PCA), and cluster analysis (CA) were employed. The PCA, CVA, and CA showed differences between KheirAbad and Fahlian populations. This result showed that geometric morphometric methods can be used to separate the populations of the Bushehr Basin. However, further molecular studies are required to address more details.

Sampling was conducted to evaluate the fish species diversity in fourstations in the Sanandaj Azad Dam ecosystem from summer 2017 tospring 2018. A total of 1, 057 fish including 12 species were captured, 80%of the fishes were captured from the dam lake. Cyprinidae was the mostdominant family with 11 species and only one species fromNoemachilidae family (Sasanidus kermanshahensis) was recorded. Therewas no significant difference between Shannon species diversity in thedam lake (mean ± SE: 1. 11 ± 0. 32) and Komaci River (p> 0. 05), However, a significant difference was observed in the summer compared to otherseasons (p <0. 05). The size and weight of the populations in the dam lake were significantly higher than those in the river (p <0. 05). Among the identified fish species, five species Carrasius auratus, Cyprinus carpio, Hemiculter leucisculus, Hypophthalmicthys molitrix, and Pseudorasboraparva are exotic species. The competition of exotic fish species withnative species for food could have a negative impact on the speciesdiversity, population dynamics, and population of native fish species. Sasanidus kermanshahensis is an endemic species for Iran, which is veryimportant for protection. Considering the importance of the endemicspecies and the presence of a considerable number of exotic fish species inthe Azad Dam ecosystem, the result of this study is important forimplementing protection and management strategies.

Knowledge of the biological requirements of aquatic organisms in perennial rivers is necessary for the protection of biological diversity in riverine ecosystems. Habitat knowledge includes using models for estimating specific properties from the physical structure of rivers by simple and accurate methods. A fuzzy regression model was used to investigate the abundance and diversity of the two endemic fish species (Paracobitis hircanica and Neogobius pallasi) in the Zarin Gol River (located in northern Iran) in summer 2017. P. hircanica and N. pallasi overlapped in mesohabitat use, both fish species preferred riffles 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. pallasi tilis. The 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 the regression equation structure. The result recommends that the various substratum compositions may have accounted for the coexistence of these two benthic fish species. It also provides important information for habitat management and ecological engineering of Mountain Rivers in Iran.

Due to the high morphological similarities among populations and species of Ponticola genus in the southern Caspian Sea, it is difficult to identify them based on the provided keys. Molecular markers are used as a supplementary tool to a better understanding of the taxonomic status of fish species. This study was conducted to understand the taxonomic status of gobiids from six rivers (Siah, Zaringol, Babol, Tajan, Sefid vis. Bijar and Kisum populations, and Kelsian) in the southern Caspian Sea basin. The taxonomic status was studied 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 showed a mean genetic distance (K2P) of 0. 69-1. 68 among the studied populations which is too low to consider them as distinct species based on the genetic criteria. Also, BI and ML cladograms and haplotype network showed that all populations are haplotypes of P. gorlap.

The present study examines the developmental stages of the eye retina in Caspian kutum during the pre-hatch stage to the end of the larval stage. Fertilized eggs were obtained from Shahid Ansari Center for the reproduction of teleost fish (Guilan Province, Iran). Sampling was conducted for one month until when the larval stage completed and the yolk sac completely depleted. Samples were studied using optical and electron microscopy. On the third day after fertilization (68hpf), the primary optic structure was observed. The undifferentiated neural epithelium was placed around the lens placode originated from ectoderm. At 5dpf (120hpf), the eye was spherical and the optic cup was formed. The first retinal stratification was initiated at the 9dpf (216h. dpf) and cone cells appeared in the retina, while rod cells that only function in low light conditions, appeared after hatching at the fourth posthatching day. The cellular arrangement continued until several days after hatching. Along with the growth and development of the eye, the lens grew by the addition of secondary lens fibre cells proliferated from lens epithelium cells. Also, the primary lens fibre losing nuclei and other membranous intracellular organelles. The results obtained from the diameter of the lens and the cone density represented that the visual acuity of Caspian kutum larvae increases at the end of the larval stage.

The present study aimed to investigate the effects of dietary aliphatic sodium butyrate on some haematological parameters and growth indices in common carp fingerling with an average weight of 10 g. This experiment was conducted for 8 weeks using four different diets with three replications including control (without supplement) and three levels of sodium butyrate (0. 25, 0. 5, and 1%). Fish were fed twice a day (3% body mass of the fish) for 2 months and the biometric measurements were taken 2 times in a month. At the end, haematological parameters (including the number of red blood cells, white blood cell count and fractional count, hematocrit, and haemoglobin), and growth factors (final weight, specific growth factor, feed conversion ratio, and consumable food intake) were evaluated among the experimental groups. This experiment was performed in a completely randomized design. Data analysis was performed using SPSS and Excel software packages. Finally, there was no significant difference in the final weight, specific growth factor, feed conversion ratio, and food intake among the experimental groups. The results of this study showed that sodium butyrate had no effect on the number of red blood cells, hematocrit, haemoglobin, mean corpuscular vein (MCV), moderate haemoglobin (MCH), and moderate haemoglobin concentration (MCHC). There was also a significant difference in the levels of white blood cells in 0. 25% and 1% groups compared to the control group. No significant difference was observed in the levels of white blood cells between the 0. 5% group 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 haematological parameters, however, the number of white blood cells decreased in 0. 25% and 1% groups.

To prevent the negative impacts of antibiotics, it is recommended to use other alternatives such as probiotics, prebiotics, and organic acids, which can have positive effects on the physiology of aquatic animals. This present study aimed to investigate the synergistic effects of organic acid (potassium sorbate) and probiotic (Lactobacillus casei) on rainbow trout fry (O. mykiss). Three hundred and sixty rainbow trout fry (mean weight ± SE: 2. 45 ± 0. 05g) were provided and randomly distributed in six treatments with three replications for each treatment including commercial diet (control, treatment 1), 10 7 CFU/g probiotic (L. casei) (treatment 2), a diet containing 0. 5% of potassium sorbate (treatment 3), a diet containing 1% potassium sorbate (treatment 4), a diet containing 0. 5% potassium sorbate and 10 7 CFU/g probiotic (L. casei) (treatment 5), a diet containing %1 potassium sorbate, and 10 7 CFU/g probiotic (L. casei) (treatment 6). The feeding trial was applied in two stages for a period of 60 days. At the end of the experiment, digestive enzyme activity, intestinal histomorphology, and the resistance of fry fish against pathogenic bacteria (Yersinia ruckeri) were investigated. The highest alkaline phosphatase and protease enzyme were observed in treatment 5 and the lowest in the control group. Intestinal histomorphology showed the highest length of Vili and its diameter in treatment 5 and 6 and the lowest was observed in the control group. After the resistance test against Y. ruckeri pathogen bacteria, the highest mortality rate was observed in the control group and the lowest observed in treatment 5 and 6. Based on the results of this study, it seems the use of combination probiotic and organic acid in the diet can increase the production of rainbow trout

In recent years, drugs have been identified as newly emerging and threatening pollution in aquatic and terrestrial ecosystems. Therefore, in this study, the effect of indomethacin on oxidative stress in Cyprinus carpio was investigated. In order to determine the LC50, fish were exposed to various concentrations (30. 60. 100, 150, 250, and 400 mg/l) of indomethacin and daily mortality were recorded during 96 hours. In the next step, fish were exposed to various concentrations of indomethacin (0, 0. 01, 0. 02, 0. 05, and 0. 1 time of LC50 96h) in five treatments including T1 (control), T2 (3. 3), T3 (6. 4), T4 (6. 6), and T5 (32. 8 mg/l) 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. The lethal toxicity (LC50) of indomethacin was obtained for carp (328. 49 mg/l). GPX had higher activity in gill and liver in all treatments compared to the control group. MDA levels in liver in T4 and T5 groups and gill tissue in T3 and T4 groups showed a significant increase compared to the control group. Also, CAT had higher activity in liver and gill in T4 and T5 groups compared to the control group. Indomethacin leads to stress by increasing the production of reactive oxygen species and increasing lipid peroxidation, therefore, it is exposed to the antioxidant system of liver tissue and gills of fish and induces a response in the form of increased antioxidant enzyme activities. The results of this study demonstrated that the presence of indomethacin in an aqueous environment can influence the antioxidant status and health of the fishes.

This study was conducted to survey the distribution and abundance of cutlassfish (Trichiurus lepturus, Linnaeus 1758) as a target species in the fishing grounds of Bushehr and Hormozgan Provinces. Sampling was carried out during summer 2013 in the Bushehr Province and autumn 2013 in the Hormozgan Province. The fishing operation was performed using a commercial trawler vessel with a length of 27 m and 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 from 84 to 92 cm and the least length-frequency was from 28 to 36 cm. The biomass and mean CPUA in Bushehr Province were 17169. 55 tons and 8624. 42 ± 1076. 58 (kg nm-2 ) and in Hormozgan Province were 7425. 804 tons and 8105. 74 ± 1529. 87 (kg nm-2 ), respectively. Also based on depicted maps using 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 Bushehr Province.

This study aimed to evaluate the effect of silver nanoparticles (AgNPs) on taste feeding behaviour including taste palatability index, fishing efficiency, and the number of consumed pellets to some selected amino acids in juvenile Persian sturgeon (A. persicus). Taste Feeding behaviour was investigated in the following exposure concentrations: 0. 01, 0. 005, and 0. 001 mg L-1 AgNPs for 21 days (each group with three replicates and each replicate with seven fish). Then, the feeding behaviour of fish was investigated using experimental pellets containing 0. 3% chromium oxide, 2% agar, and some selected amino acids (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 two concentrations of 0. 01 and 0. 005 mg L-1 AgNPs. Also, the number of consumed pellets was significantly lower than the control for all amino acids. Furthermore, AgNPs at all concentrations significantly reduced the fishing efficiency in some amino acids including arginine, cysteine, and tyrosine. Considering that the even the lowest concentration of AgNPs (0. 001 mg L-1) had negative impact on taste feeding behaviour of Persian sturgeon. Therefore, it is recommended to keep the concentration of AgNPs at the minimum level (less than 0. 001 mg L-1) before releasing to the aquatic ecosystems.