نشریه پژوهش های ماهی شناسی کاربردی
سال سوم شماره 1 (بهار 1394)

Shemaya (Alburnus chalcoides) is the most important bony fishes in the Caspian Sea that migrate to breed in Anzali wetland. The present study was conducted in order to study reproductive biology in male migrant Shemaya to Anzali wetland during spawning phase from March 2013 to Jun 2014. Microscopic images of histological gonad and rate of sex steroid hormone in 16 numbers of adult male fish were studied. Results showed that the testis of fish was lobular. The result of histological image inmale fish showed that gravid fish was in the beginning of active spawning phase¡ and the spermatogonia (SG) in addition with different stage of spermatogenesis (Sc¡ St¡ Sz) were poorly observable in their tissue sample. This is while there was not observed primary stage of spermatogenesis (Sc1¡ Sc2) and spermatogonia in spawning fish andtheir lumen was full of spermatozoa that indicated the final stage of spawning. The result of sex steroid hormones showed that the rate of testosterone hormone in spawning fish was 12.13±0.68 ng/ml and in gravid fish its value was calculated as 8.77±0.55 ng/ml (P

To determine genetic diversity of Paracobitis hircanica in Tilabad, Touskestan and Zaringol rivers of Golestan province, six microsatellite markers were utilized all of which showed polymorphism. Investigation of genetic differentiation revealed the Fst of 0.028, indicating low genetic differentiation among the samples of the studied regions. Also, investigation of Hardy-Weinberg equilibrium showed significant deviation from Hardy-Weinberg equilibrium in 16 samples of 18 tests of population-loci mostly due to the observed heterozygosity deficiency. The number of alleles and observed heterozygosity was 8-16 (the average of 11.94) and 0.03-1/00 (the average of 0.52), respectively, which are slightly higher than the amount reported for fresh water fish. Results indicated that P. hircanica has high allelic richness and considerable genetic diversity in the investigated regions. Additionally, analysis of molecular variance revealed that most of the observed diversity was within populations and there is low diversity among the populations. Results from genetic distance represented that there is probably separate populations of P. hircanica in Golestan Rivers.

This study was carried out to identify the impact of some environmental variables including water surface temperature, air pressure, and wind current speed on the catch rate of grouper fish (Epinephelus coioides) using long line method in the north west water of the Persian Gulf (coastal province of Khuzestan). Sampling was carried out in three seasons of spring, summer and autumn in 1391 and two seasons of summer and autumn in 1392. Data analysis revealed high correlation among current speed, air pressure and catch rate. The study showed that the amount of catch in the summer increased significantly with a rise in surface temperature, air pressure and a decrease in current speed. Therefore, summer is better than other seasons to catch this species

The Present study was conducted to determine some population dynamics parameters of Paracobitis hircanica in Garmabdasht River in Golestan Province during 2011. Sampling was done seasonally using electrofishing (in five stations). The results showed that the male to female sex ratio is1:1.17 which is not significant. The results indicated that the growth rate is greater (or faster) in females than males and also the infinite length of females is greater than males. Both sexes had negative allometric growth model and the condition factor for both sexes was the highest in summer which depends on the better nutritional conditions of this season in comparison with the other season

Ammonia accumulation in the earthen ponds is unavoidable and is considered as one of the serious problems of aquaculture. In this study susceptibility to chronic exposure of sub lethal ::::::union::::::ized ammonia (NH3) in Caspian roachwas investigated. In this regard, two treatment groups and one control group (with three replicates for each one) were considered. Fish of treatment groups were exposed to 0.2 and 0.02 mg/l ::::::union::::::ized ammonia (NH3),respectively during one month rearing period while no ammonia exposure was done in fish of control group. According to the results, most growth factors in theexposed fish to 0.2 mg/l ::::::union::::::ized ammonia were significantly lower compared to both control group and theexposed fish to 0.02 mg/l ammonia (P&le0.05). In hematology study, hemoglobin, hematocrit, MCH and MCHC counts for theexposed fish to 0.2 mg/l were recorded lower compared to fish of both control and the exposed fish to 0.02 mg/l ammonia. However, blood MCV index were significantly recorded higherin theexposed fish to 0.2 mg/l ammonia compared to fish of other groups. According to the results of present study although chronic ammonia exposure at 0.2 mg/l concentration did not lead to mortality in Caspian roach, it can be considered as a harmful dosage for growth and hematologic indices in this fish. This is while long-time exposure to 0.02 mg/l ::::::union::::::ized ammonia has no negative effect on growth and hematological indices in Caspian roach fingerlings

In this research the effect of starvation on growth performance, insulin and blood serum metabolites were studied in order to assess compensatory growth mechanism in Persian sturgeon (Acipencer persicus) juveniles with average weight of 108.04± 0.28 gr (± SEM) in the same rearing condition during 8 weeks. This survey was designed in random with 5 treatments in 3 replicates which consist of control group (C, without fasting), 1w (1 week), 2w (2 weeks), 3w (3 weeks) and 4w (4weeks) starvation followed by 4 weeks of re-feeding in satiation. Results revealed that morphological factors including body weight, specific growth rate (SGR), condition factor (CF) and weight gainwere decreased significantly during starvation period.However, growth was increased after re-feedingand weight was compensated in different treatments.In addition, Blood plasma glucose and insulin during fasting and re-feedingdid not change significantly in comparison with the control group. This indicates high performance of this species in themaintenance of blood glucose during starvation and recovery of plasma glucose level after re-feeding. Whereas, plasma total lipid and triglyceride level in fasting treatments were increased. This showed a significant increase in 3w treatment that in 3w treatment(p

A fish species that lives in two different geographical regions may have some minor or evident differences in frequency and diversity of ectoparasites. Physical and chemical differences of water source, presence of intermediate hosts of some parasites and many other complicated factors interfere in this aspect. This research was done during 36 months from 1388 to 1391 in rainbow trout farms of Qazvin province to study the effect of water source in frequency and diversity of ectoparasites of Cultured Rainbow Trout. For this purpose 1150 rainbow trouts with clinical signs from seven farms with will source and average temperature of 15ͦ c and three farms which receive water from river system with average temperature of 11 ͦ c were caught and transferred alive to the laboratory of veterinary medicine department of Qazvin. Parasite experiments were done using the wet smear of skin, and checked with identification key. Results showed that the farms with river system, despite situating one after another, had less frequency and diversity of ectoparasites in comparison with fish which receive water from the will with higher average temperature. The parasites in river-system farms were consist of Trichodina sp. with the most frequency in spring, Ichthyophthirius sp., Gyrodactylus sp., Dactylogyrus sp. and Ichthyobodo sp. with the most ffequency in summer and also Chilodonella sp. with the most frequency in winter. The parasites in will farms were consist of Ichthyophthirius sp.,Trichodina sp.,Gyrodactylus sp., Dactylogyrus sp. , Chilodonella sp., Lernaea sp., Epistylis sp., Tetrahymena sp., Cryptobia sp. and Vorticella sp. from which the most frequent infections were Ichthyophthirius sp. and Tricodina sp. with the most frequency in summer and fall, respectively, and Chilodonella sp. with the most frequency in winter

The present studywas conducted to evaluate the effect of different levels of dietary alphamune and protexin alone and/or in combination on growth performance of juvenile common carp (Cyprinus carpio). This experiment was conducted using juvenile common carps with initial average weight of 7.01±0.02 g during 60 days. The investigated were protexin (0 and 0.75 g/kg) and alphamune (0, 0.5 and 1 g/kg) based on which six experimental diets were formulated. Each experimental diet was randomly assigned to triplicate 40-L tanks with stocking density of 10 each. Fish were fed by hand three times day at 3-5% biomass during the experiment. Results showed that inclusion of dietary alphamune significantly affected growth related parameters, such as final weight, growth and specific growth rate (p