Parasite infection of 256 specimens of BREAM (Abramis brama orientalis) surveyed in Aras Dam Lake in the years of 2008-20009. According to the results, 5 parasites recognized. including Trichodina sp (prevalence=25%, Mean intensity±Standard=2.41±0.11 and Range in number 1-11, Gyrodactylus sp (prevalence=23/43%, Mean intensity±Standard=2.49±0.12 and Range in number1-8), Dactylogyrus sp(prevalence=10/54%, Mean intensity±Standard=1.81±0.09 and Range in number 1-6), Diplostomum sp metacercariae (prevalence=4/29%, Mean intensity±Standard=3.73±0.1 and Range in number 1-6) and Ligula intestinalis plerocercoid (prevalence=45/7%, Mean intensity±Standard=3.09±0.07 and Range in number 1-6). The frequency and infection of parasites were statiscally different between age classes, stages, male and female. In different age's most and latest prevalence infection due were 56/92% to L.intestinalis in 3+ and 0% to Dactylogyrus sp and Diplostomum sp in 2+ respectively. In different male most and latest prevalence infction due were 53/8% to L.intestinalis and 0% to Diplostomum sp respectively. In different female most and latest prevalence infection due were 44/6% to L.intestinalis and 5/39% to Diplostomum sp respectively. In different 4+ most and latest prevalence infections due were 56/92% to L.intestinalis and 4/61% to Dactylugyrus sp respectively. In different stages most and latest prevalence infections due were 71/65% to L.intestinalis in first stage and 17/3% to Diplostomum sp respectively in second stage. There species of Gyrodactylus sp and Diplostomum sp are reported in BREAM for the first time from Aras Dam Lake.

This study was conducted to examine morphometric and meristic characteristics alongside pigmentation patterns of BREAM larvae, Abramis brama orientalis, in four stages of larval development. Morphological characters including total length (TL), standard length (SL), notochord length (NL), head length (HL), head depth (HD), eye diameter (ED) and mouth width (MW) were examined from hatching time through 30 days after hatching (DAH). The re-sults showed morphometric variations in the different larval stages. Growth and development of fins occurred mainly at the Post Flexion stage with the completion of caudal fin at 9 mm TL and pelvic fin at 13.33 mm TL. At all larval stages, the highest concentration of pigments was seen on dorsal, ventral and somewhat on the lateral sides of body in descending order. The highest density of melanophores at larvae yolk sac stage was observed on the yolk sac and the back of head zone, while at preflexion and flexion stages melanophores were dominant on the back of head and on the skin folds which resulted from yolk absorption. At post flexion stage, high density of melanophores was found on the back of the head, bases of fins and caudal fin, while less concentrations of these cells were evident on the lateral sides of fish' body. In conclusion, a clear change in the growth and main morpho-logical characters were observed in postflexion stage. This may be due to the main development of fins, which would suggest enhanced swimming capabilities and also prey capture efficiencies.

BREAM (Abramis brama orientalis) is one of the most commercially valuable fish in the Caspian Sea. The aim of this study was to compare levels of genetic polymorphism between wild and farmed BREAM populations using seven microsatellite loci. Genetic diversity was investigated by studying samples collected from two regions; Chaboksar and the Artificial Propagation Center of Guilan province. Allele frequency was found to have declined in wild and cultured fish due to inbreeding and genetic drift. Significant population differentiation (Fst) was observed between wild and farmed populations, which could be explained by the low number of alleles in two populations. Significant deviations from the Hardy-Weinberg equilibrium were found at more loci. Beyond the null alleles' hypothesis, heterozygote deficiency may have arisen due to inbreeding. Both populations showed lowest genetic diversity according to the number of alleles and genotypes per each locus. This approach was carried out for the first time and could provide information regarding the genetic variability of farmed and wild abramis brama fish using microsatellite markers. Results could be used for the management and conservation of artificial BREAM propagation programs.

Common BREAM (Abramis brama orientalis) is one of the valuable bony fish of Caspian Sea and Aras Lake. In the present study parasite infections of Common BREAM in Alagol Lake have been studied. In this regard, 31 fish specimens were considered for abdominal cavity parasite study. After biometry and parasite isolation, final detection of parasites species was done in Iranian National Parasitology Museum, faculty of veterinary medicine of the Tehran University. According to the result 2 nematodes parasite including Eustrongylides excisus and Anisakis simplex and 2 trematode parasites including Asymphyllodora tinca and Pronoprymna ventricosa were isolated from abdominal cavity of specimens. Result showed 58% of specimens were infected with parasite that Asymphyllodora tinca has highest prevalence and intensity of parasites and Eustrongylides excisus has lowest prevalence and intensity of parasites in this study. In this study Anisakis and Eustrogylides because of their zoonotic properties are most important in human health so in this regard, health hazards should be considered by consumers.

During 1381 year, morphometric specialities, meristic and proportion of morphometric particulars of the BREAM (Abramis brama orientlis) the Caspian sea (90 pieces) and Anzali wetland (120 pieces) was studied and compared. According to results, average of changes coefficient the above factor in the BREAM of Caspian sea were respectively 22.36, 3.24 and 7.56 percent and in the BREAM of Anzali wetland were 22.76, 4.63 and 21.56 percent. Meanwhile, it is observed the different meaningful of statistical (ANOVA), from 40 morphometeric factor, 16 morphometric spacialities respectively in 33, 3 and 26 factor. According to test of Factor Analysis BREAM of this two area choosing in 6 first morphometeric (Total leanght, forke length, standard length, head length, head height, snout length) 80.02% changes (rate of KMO equal 0.94), in 4 first meristic (number of scale the lateral line, number of scale under the lateral line, number of scale above the lateral line, number radius of dorsal fin) factor 60.42 % changes (rate of KMO equal 0.47) and in 7 first factor proprtion of the morphometeric (proportion of head length to standard length, head height to head length, snout length to head length, mount width to head length, mount length to head length, throat length to head length and eye diameter to head length) 73% rate of KMO equal 0.82 of this factor, caeuse separating of two population from together. So, according to the Descriminatiion test according to two first and secind factors of morphometeric (Total leanght, forke length), meristic(number of scale the lateral line, number of scale under the lateral line) and proportion of the morphometeric specialities (proportion of head length to standard length, head height to head length) of the Abramis brama orientalis of this two area will totally separate (rate of focus espectively equals 0.88,0.3 and 0.86). finally, with attention to results, we can say that there are significant different between the BREAM of Caspian sea and Anzali, wetland in morphometeric factors, while, this different is very little in meristic factors, the reason of this differents, is causing of variation condition of habitat and the effected on the meristic factors. Because, this factor is not affected on the meristic factors is dependant of genetical changes.

BREAM (Abramis brama orientalis) is one of the most commercial valuable fish species of the Caspian sea. Total catch of this species was 17 tons in 2000 -2001 fishing season, which constitute 0.10 % of the all commercial catch of fish species in Iranian coastal water. The mean fork length, weight and age of this species was 21.7±3.3 cm, 191±99.9 gr and 2.72±0.91 year (X±S.D) respectively. Length - Weight relationship was expressed as W = 0.2312 L 2.90 (R 2= 83.34 %, r = 0.91, N=160). Length growth parameters of BREAM based on Von Bertalanffys can be written as: Lt = 45 [ 1 -exp -0125(t+2.768)] The instantaneous rate of total (Z) , Natural (M) and fishing (F) mortality coefficients were 0.92 year -1, 0.28 year -1 and 0.64 year -1 respectively .The exploitation ratio (E) was calculated as 0.7 . Based on cohort analysis, the biomass of this species was calculated as 46.362 tones and according of this amount of biomass, the MSY was estimated as 14.99 tones which is less than the catch of this species.

Some biological aspects of BREAM (Abramis brama) such as seminal plasma indices (ionic and organic composition) and their relationships with sperm motility were investigated. Seminal plasma contained 59.05±8.27 mmol/l Na+, 1.65±0.354 mmol/l K+, 5.95±1.45 mg/dl Ca2+, 18.36±3.46 mEq/l Mg2+, 0.150±0.055g/dl protein, 29.42±7.17 mg/dl cholesterol and 38.11±8.59 mg/dl glucose. Semen spermatocrit was 35.35±8.06%, pH 7.69±0.227 and duration of spermatozoa movement was 56.30±14.18s. The sodium/potassium and calcium/potassium ratios were 35.78 and 3.60, respectively. Spermatazoa in two out of 10 BREAM semen samples were motile in seminal plasma.There were no significant correlation between ionic and organic composition of the seminal plasma and sperm motility (p>0.05), but there were significant negative correlation between glucose and spermatocrite (r=-0.785, p<0.01).Consequently, although there were no definite correlations between biochemical and spermatological parameters, it was observed that higher spermatocrite content had negative effect on glucose content.

In the present study LHRHa2 was tested along with Metoclopramide and Chlorpromazine on 52 pieces of Abramis brama orientalis in May 2008. In order to identify the optimum doses which were proved to be (1, 2, 3, 4 mg/kg) for LHRHa, (5, 10, 15, 20 mg/kg) for Metoclopramide and (2, 5, 10, 12 mg/kg) for Chlorpromazine. The treatment sample fish were classified into five categories, and then the injected solvents were prepared. The procedures of the study included injection operations into the muscles and cupping was in the form of sagittarius hemal. After that, GTH II was conducted on the basis of RIA. The findings proved that all the compositions in a stimulating process resulted in an increase in the ration of GTH II and at P<0.05 resulted in meaningful differences in optimum dose. LHRHa2 (3 mg/kg) led to 0.554 IU/L, Metoclopramide (5 mg/kg) caused 0.618 IU/L and also Chlorpromazine (10 mg/kg) resulted in 0.522 IU/L increase in the ratio of GTH II.

The aim of the present study is to evaluate the inhibitory effect of bacterial strain Staphylococcus equorum on growth performance of pathogenic bacteria, Aeromonas dhakensis. As A. dhakensis is a pathogenic strain for many kind of the fish species in the domain of aquaculture industry and being introduced as a threat, it will be beneficial to inhibit this bacterium by use of a biological procedure instead of using chemical antibiotics, such as applying probiotics. Staphylococcus equorum seems to be a good candidate among the staphylococci group. In this regard after preparing pure cultures of both strains, the inhibitory effect was being determined through inducing both strains in BHI media and monitor the growth curve and also inducing the strains in TSA media and counting the colonyforming units. The results showed that Staphylococcus equorum has an inhibitory effect on Aeromonas dhakensis, but the reduction of colony forming units were not significant (P>0.05), and can be introduced as a remarkable probiotic strain, but it should be mentioned that it is necessary to distinct the inhibitory process.