نشریه پژوهش های ماهی شناسی کاربردی
سال ششم شماره 4 (زمستان 1397)

The phenomenon of climate change is the greatest environmental challenge facing in the world today. The phenomenon is expected to affect all ecosystems in the world. Freshwater ecosystems are more vulnerable to these changes, as freshwater is exposed to various human pressures such as hydrology, morphology, connectivity and water quality. Therefore, climate change along with the mentioned issues will exacerbate the impacts on freshwater communities. In this study, with using the Species Distribution Modeling (SDM) tool, the effects of climate change on the distribution of Kura bleak was modelled by nine different algorithms (i.e. GLM, GAM, GBM, RF, CTA, FDA, MARS, ANN, SRE) under two optimistic (RCP2.6) and pessimistic (RCP8.5) climatic scenarios including two temporal scales (i.e. 2050 and 2080). According to the True Skill Statistic (TSS), the overall performance of the models has been excellent. The results of modelling also show that the distribution of this species in all climatic scenarios will be seriously reduced (100%) on the both temporal scales, and no new potential area for distribution of this fish was also predicted. Therefore, the results of such research provide valuable information to decision makers in order to conserve species better.

The aim of the present study was to examine the effect of temporal variations and tidal phases on frequency of Upeneus doriae (Günther,1869) in the coast of Bandar Abbas. Sampling was performed in September 2016 to April 2017. During the lunar calendar months, the highest abundance of U. doriae  was observed in Muharram (with147/15 ± 144/37 n.G-1.day-1 ), and lowest was in Rabi Ul Awal (with 3/53 ± 3/5 n.G-1.day-1). The selected species was also most abundant in the western region of Bandar Abbas coasts (205/1 ± 137/01 n.G-1.day-1 ), and lowest frequency was observed in central region of coasts (28/55 ± 22/88 n.G-1.day-1). Data analysis approved the temporal and spatial variation of U. doriae abundance in Bandar Abbas coasts. The mean total length and weight of the specimens were also 10/57 ± 1/43 cm and 18/19 ± 5/86 gr, and the total length-weight relationship was calculated W=0/01397L3/0456. Data of Length frequency distribution also showed that length classes 10.5-11.5 and 14.5-15.5 cm had the highest and lowest abundance among the caught samples, respectively. The mean relative condition factor (Krel) and relative weights (Wr)of caught specimens were calculated as 1/005 ± 0/320 and 0/890 ± 0/178, respectively.

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.

Bone gla protein and matrix gla protein are of common origin with evolutionary relation and have similar structural features and are functional in the formation of skeletal structures The present study have been evaluated the genes encoding vitamin k-dependant proteins (VKDPs) expression at hatching time (0), 1, 3, 6, 10, 12,14, 20, 30 and 50 in skeletal Persian sturgeon sturgeon (Acipenser persicus Bordin, 1897). The results of quantitative real-time PCR showed that the transcripts of VKDPs genes including bone Gla protein (bgp) and  matrix Gla protein (mgp ) were significantly up-regulated during the transition to the exogenous feeding, confirming the hypothesis about the relevance of the above-mentioned genes in chondrogenesis at early developmental stages. Maximal levels of bgp and mgp expression at juvenile stage, indicating the importance of these genes in the mineralization of the skeleton in sturgeons, although these genes are also expressed in other body tissues. This information can be considered as a reference for other studies evaluating the quality of larvae and the influence of rearing biotic and abiotic factors in the skeletogenesis of this sturgeon species and the occurrence of skeletal deformities.

Persian sturgeon (Acipenser persicus) is one of the most valuable species of fish native to the Caspian Sea and Iran's waters. This study was designed to estimate heritability of Persian sturgeon eggs. In this study, 3 wild Persian sturgeons caught from the south coast of the Caspian Sea in Guilan and transferred to fish breeding programs in Shahid Beheshti rearing and propagation complex were used during 2016. Characteristics including the weight and diameter of eggs at blastula, gastrula and neurola embryological stages. To estimate heritability, 270 eggs were sampled at each stage of fetal development. Variance components was estimated using software R linear mixed model (LMM) closed Lme 4. Results showed that heritability of eggs weight and diameter  at blastula stage 0.218±0.422 and 0.375±0.145 ,at gastrula stage  0.033±0.062 and 0  and at stage neurola was  0.377±0.45 and 0.272±0.564 , respectively. Genetic value in female 3 and male 3 brood stocks was 0.787 and 0.287, respectively. Correlation between these two variables 0.106, 0.44 and 0.43, respectively. Overall, heritability of average egg weight and diameter showed that selection for these traits could be had a positive source of genetic origin.

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.

This study was conducted to evaluate the influence of exogenous supplement Natuzime plus enzyme on growth performance, body composition and survival rate of beluga (Huso huso) juveniles. Juveniles (n = 17 fish per each tank with initial weight of 30 g) were randomly distributed in 150-L tanks and fed with four diets (each in three replicates) containing 0, 2, 5 and 10 % of Natuzime plus multi enzyme for eight weeks. Results showed that survival rate of the fish were in the range of 83-95 % and there were significant differences between treatments. The highest weight gain was recorded in fish fed with 2 % enzyme and being different from the other groups. The specific growth rate was to be ranged from 1.96 (10 % enzyme) to 2.32 (2 % enzyme). Feed conversion ratio, protein efficiency ratio and daily growth rate were significantly higher in the diets containing enzymes compared to the control group; and the best performance was attained in 2 % enzyme in the diet. The highest (69.5 %) body protein content was recorded in the fish fed with 2% enzyme in the diet. The results obtained suggest that dietary inclusion of 2% Natuzime plus enzyme can improve the growth performance and survival rate of beluga juveniles.

The research was accomplished to determinate sub lethal concentration (LC5096h) of Nikel and Iron on Rutils frisii kutum. The study was performed by Water Static Method during 96 hours. The experiments were done by 13 fish with avrage weight 1±0.5 g. The fish were encountered with different concentrations of Ni (5, 15, 25, 30, 35, 40 mg/l) and Iron (100, 120, 140, 150, 155, 160 mg/l) respectively. Sulphate Nikel salt and Iron Sulphate salt were used as source of Nikel ion and Iron respectively. A group of fish was considered as control. Tempereature and pH were stable in experiments.  Under stable condition and aeration, the lethal concentration of Nickle  and Iron were detected  equivalent 40 mg/l and 155 mg/l respectively. Sub lethal concentration of Nickle and Iron were  19.35 mg/l and 124.52 mg/l respectively by used of linear regression of mortality percentage to ammonia different concentrations. Results indicate significant differences between treatments with each other (p<0.05). However,  in the high concentrations of Nikel and Iron nominal signs of toxicity as convulsion and opened operculum were observed. In microscopic tissue studies of gills showed hyperemia, hemorrhagi cell necrosis and influx of inflammatory cells.

Regarding the revealing side effect of chemical medications, such as antimicrobial resistance and etc, herbal medications have been considered as one of potential alternative to chemical one. The main purpose of this study was to evaluate the in vitro antibacterial effect of lavender ( Lavandula angustifolia) and ajwain ( Trachyspermum ammi) essential oil on two important rainbow trout bacteria; streptococcus iniae and Lactococcus garvieae .In addition, antifungal activity of Clove (Eugenia aromatic) and lavender essential oil were assessed as well. Disc diffusion method was used to test antibacterial activity. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by using standard procedure Broth- microdilution. The results obtained demonstrated that Streptococcus iniae and Lactococcus garvieae were most sensitive to ajwain with inhibition zone of respectively 26±1mm & 24.33±1.15mm , which was significantly higher than amoxicillin , erythromycin and lavender (p<0.05). Moreover, ajwan essential oil showed the lowest MIC (0.049±0.01) compared to the other group. Antifungal activity of clove oil and lavender did not show significant difference comparing to Clotrimazol. However, these two herbal agents could not compete with Amphotericin b whith the highest zone of inhibition (13mm) (p<0.05). Therefore clove oil , lavender and ajwain essentialsare suggested as natural anti fungus and anti bacteria agents in aquaculture activities.

The present study was conducted on the comparison of morphometric and meristic factors among Alosa caspia (Eichwald, 1838) populations in the southern Caspian Sea basin. A total of 285 Alosa caspia specimens were caught from three localities, from west to the east of Caspian Sea including Guilan (Bandar Anzali), Mazandaran (Sari) and Golestan (Miankale) provinces. Thirty morphometric and ten meristic traits were examined. The results of principal components analysis, the discriminant factor analysis and canonical variates analysis on the counting traits indicate the little difference of specimens among populations. Therefore, it can be stated that differences in environmental and nutritional conditions caused relatively poor morphological differences among the populations studied. However, these results need to be verified by further studies on genetic, physiological and osteological characteristics in the populations.