In this study, the serum enzymes (ALT, AST, ALP, LDH) levels were determined in three carp species: Grass carp, silver carp, and common carp. For this purpose 50 blood samples were taken from each species. The fishes were apparently normal.The averages of LDH, ALP, ALP, AST, ALT values in common carp were 1125, 285, 53 and 18 unit respectively. These averages in grass carp were 1540, 255, 34 and 16 unit, and in silver carp were 1556, 126, 40 and 14 respectively. The range of LDH activity in grass carp was between 1484 and 1595. This range for silver carp was between 1462 and 1650 and 1000 and 1250 in common carp. For ALP this range in grass carp was between 196 and 314, in silver carp between 97 and 156 and in common carp between 234 and 337. The range of AST activity in grass carp was between 26 and 44 in silver carp 33-34 and 43-63 common carp. The ALT activity was 13-18 in grass carp 11-16 in silver carp and 11-16 in silver carp and 15-21 in common carp. The range of LDH enzyme activity in common carp was significantly higher than two other species (p<0.05).ALP level in silver carp was significantly lower than in the other species (p<0.05). The average of AST activity in common carp was significantly higher than grass carp (p<0.05). There wasn't any significant difference between these three fish species in the ALT levels.

Objective: Isolation and identification of fungi from gill lesions.Samples: Gill specimens from the common carp (Cyprinus carpio), silver carp (Hypophthalmichthys molitrix), grass carp (Ctenopharingodon idella).Procedure: The samples were obtained from the five fish farms in Mazandaran province and transferred to mycology laboratory with ice conditon. The samples were inoculated in culture media (Sabouroed glucose agar, glucose pepton agar and corm meal agar+ choloramphenicol).Statistical analysis: Chi-square and t-test. Results: Thirty-nine species of fungi were isolated from the gill lesions. The most important pathogenic fungi were Branchiomyces, Saprolegnia, Fusarium, Phoma and Exophiala. The most frequency isolated fungi were Fusarium (46.4ko3/4%l) and saprolegnia (25ko3/4%l), whereas Exophiala (3.6ko3/4%l) was showen the lowest frequency.Conclusion: This is the first report of isolation of Branchiomyces, Phoma and Exophila from fish in Iran. It is concluded that the above-mentioned isolated pathogenic fungi may play an important rule in fish diseases. Thus, this study should be continued into the future.

BACKGROUND: Maturity of silver carp (Hypophthalmichthys molitrix) ovary takes place at 2-8 years old and it is depends on photoperiod and environmental water temperature.OBJECTIVES: The aim of this study was to identify macroscopical and microscopical structure of silver carp ovary in two categories of body weight, total body length and at 2 and 4 years old in Khuzestan province climatic conditions.METHODS: 20 silver carp ovaries were studied in two groups: Group 1(G1): 10 fish with total body length 46±1.33 Cm and weight 1050±0.09 grand approximately 2 years old. Group 2(G1): 10 fish with total body length 86±3.64 Cm and weight 5460±800 gr and approximately 4 years old. For the histometrical studies, 5-6 m sections were made by routine paraffin embedding method and stained by H&E and PAS.RESULTS: Microscopic results showed that ovaries of G1 covered by a thin loose connective capsule which numerous of egg-bearingtrabecula extended from capsule into ovaries. These trabecula contained primary germ cells, oogonium, chromatin nocleolus, perinocleolus and cortical alveolus follicles. Ovaries of G1 do not have yolk and mature follicles. But in ovaries of G2, growth and mature follicles were observed and mature follicles were most follicles. Histometrical results showed that there are not a significant differences in diameter of follicles, oocytes and oocytes nucleolus in G1 and 2. The maximum and minimum diameter of follicles were seen in mature and chromatin nucleolus follicles respectively. The Zona plucida thickness was increased from corticalalveolus (1.53±1.11 mm) to mature follicles (6.88±0.21 mm) significantly (p<0.05).CONCLUSIONS: The most interesting finding of this study is that in Khuzestan Province climate, the ovary of silver carp fish in G1, with average weight 1050±0.09 gr and total length 46±1.33 Cm and approximately of 2 years old is immature but ovary of G2 with average weight of 5460±800 gr and total length 86±3.64 Cm and approximately 4 years old is mature.

Karyotype and number of chromosomes of silver carp (Hypophtlulmichthy. molitrix) were determined by using tissue-squashing method and gimsa staining. In this experiment 80 larvae and 10 fingerlings (weighting 1-8 g) wer examined and totaly 30 chromosomal slids were prepared. The obtain result indicated that the number of chromosomes in this species was found 2n=48 (with 88 chromosomal arms). Consist of 6 pairs metacentric (M), 14 pairs submetacentm (SM) and 4 pairs of Acrocentric (A). The karyotype formula can be stated as: (6M 14SM + 4A).

This investigation carried out on 6 silver carps (Hypophthalmichthys molitrix) with average weight 440 gr. that were in soil pond with natural products. Type, abundance and digestion amount of nutrient particles determined in gut content of these fishes. The fishes randomly caught and were sent to the lab. After biometry, they dissected and some samples were obtained from initial (5-10 cm), center (30-60 cm) and end (100 cm or more) of intestine (10 samples of each place). Then the samples were observed by microscope and the nutrient particles were identified and accounted. The results showed abundance and digestion of detritus and protozoa were more than other particles. In point of importance for consumption the feed of silver carp consist detritus, protozoa, other algae, diatoms and green algae, respectively.

In order to investigate the differences in the shape of the big-head and two morphotypes of Phytophagous fish by geometric morphometric technique, 30 samples of each group, with a mean standard length of 25 ± 3 cm, were prepared. After fish were anesthetized by 1% Clove powder extract and stabilized in formalin buffer 4%, 6-megapixel digital images of the left profile of the specimens were prepared. A total of 17 morphological landmarks were digitized by tpsDig2 software and the tps files were prepared. All non-shaped data were removed from landmark coordinates by generalized procrustes analysis. After the approval of regression between shape space and tangent space, data were analyzed using Principal Component (PCA), Canonical Variation (CVA) and Cluster Analyzes (CA) methods in PAST and TPS series. According to the results, the head length and height, the size of dorsal fin, the length of pre ventral distance, the height of caudal peduncle and the degree of posterior position of the pectoral fin in bighead carp, are some of the distinctive morphological features among species, mainly related to their ecological niche (specially feeding strategies). In the case of silver carp variants, the posterior position of pectoral fin base in silver carp-R that is close to bighead carp, may be due to hybridization between bighead carp and silver carps.

A study was conducted during the 1388 to 1389 parasites argulus foliaceus in some common fish living in marmisho lake of Urmia city were studied.63 Total numbers of fish in revier near the lake and Form Lake in winter, spring and summer caught by net fishing. Fish diction cyprinus carpio (number=33) abramis brama (number=14) capoeta capoeta (number=25) rutilus rutilus caspicus (number=9) silver carp (number=9) and grass carp (number=3). The results of these studies showed that, in 11.11 % of all fish have argulus foliaceus parasites. Parasites in the Marmisho Lake for the first time were observed and recorded.

Introduction: Mercury (Hg) toxicity, its ability to be accumulated in organism’s tissues and its stabilization throughout the natural food chain for a long period has already been proven. Mercury pollution in the environment could occur via natural physico-chemical reactions on earth crust or due to human activities which cause mercury volatilization. Both organic and inorganic components of mercury could be found in the nature. In a natural aquatic reservoir, mercury initially observed and accumulated in the members of lower trophic levels. Then it will be magnified in the tissues of top consumers. This is called biomagnification. Mercury causes disorders in respiration and blood circulation, neurotic problems, and declines the reproduction abilities in fish. Fish are known as suitable bio-indicators to detect and track heavy metals, particularly mercury in aquatic ecosystems. Accumulated mercury has been measured in different tissues of a fish. Muscle tissue, as the most consumed part of a fish body is the most important tissue to determine the level of accumulated mercury in fish. Previous studies showed that the level of mercury in Sanandaj Gheshlagh Reservoir was higher than limits established by the World Health Organization and Iranian Standard Center (i.e., 1 mg/L). Field observations verified that intensive agricultural activities and other pollutant sources such as industrial activities were not developed in Sanandaj Gheshlagh Reservoir watersheds and its upper areas. In addition, previous studies on the geological structures and soil types of the region reported high levels of mercury in the bed rock and soil texture. Therefore, it seems Sanandaj Gheshlagh Reservoir mercury pollution has a natural source. The most favorite and consumed fish in the region are Common carp and Silver carp due to their abundance and relatively low price. Therefore, the present study was designed to track and determine and compare the level of total accumulated mercury (THg) in muscle tissues of Common carp (Cyprinus carpio) and Silver carp (Hypophthalmichtys molitrix) from Sanandaj Gheshlagh Reservoir during July to December 2009.