نشریه پژوهش های ماهی شناسی کاربردی
سال هفتم شماره 3 (پاییز 1398)

In order to determine the age and growth of Chub in the Gheshlagh River of Sanandaj, two areas were selected; one in upstream of the river (Naysar; high water quality) and the other in downstream (Soaryan; impaired water quality). A total of 280 fish specimen were caught during four seasons. The overall male to female ratio was 1:1.86 in Naysar and 1:0.61 in Soaryan. Both ratios were significantly different from the expected 1:1 ratio (P<0.01). The age of individuals was from 0+ to 5+ in both areas. The overall length-weight relationships were calculated as negative allometric in Naysar and isometric in Soaryan. The fork length and body weight of fish samples in Soaryan were significantly larger and heavier than those in Naysar in most of age classes and in both sexes. The average asymptotic length was calculated as 28.2 cm for male and 35.5 cm for female based on von Bertalanffy growth equation for all fish samples in Gheshlagh river system. The overall condition factor was estimated as 1.53 and 1.5 for male and female, respectively. In most of age classes, the condition factor was significantly larger in Soaryan fish samples in comparison to Naysar samples. Results showed that some Chub biological parameters were different between two study areas. These differences could be due to the entrance of Sanandaj wastewater into Gheshlagh River in Soaryan area.

Four streams with different sizes were selected for studying the effects of environmental factors on fish assemblages using indirect (Detrended Correspondence Analysis, DCA) and direct (Redundancy Analysis, RDA) gradient analysis in Golestan province. DCA of presence-absence and relative abundance data showed well gradient and linear model of species variability. In the within-site RDA, environmental factors explained 74.8 % variability for presence–absence data and 77.5% for the relative abundance data. Evaluation of two first axis of RDA showed that first axis has a high correlation with habitat characteristics and second axis correlated with channel morphology attributes. Based on RDA diagrams, Paracobitis malapterura and Capoeta capoeta gracilis presented in Zaringol and Tilabad Streams and had a high correlation with percent of in-stream vegetation and percent of cobble in first axis and low flow mean depth and low flow width in second axis. While Alburnoides bipunctatus and Neogobius fluviatilis had high correlation with percent of snag, pool and sand within streams. It should be stated that factors such as the size of the catchment, hydrographical and geomorphological characteristics, and land use change the morphology and stream habitats, and ultimately lead to the removal of some species in adjacent streams.

In this study population dynamic of Acipenser persicus with age structure model by Monte Carlo and Bootstrap approach was studied. Length frequency data a total of 4376 specimens collected from beach seine, fixed gill net and conservation force in coastal Guilan province during 2002 to 2012. Data imported to FiSAT II for length frequency analyze by ELEFAN 1. K, L∞ and t0 estimated 203, 0.08 and -0.94 respectively. Total and natural mortality estimated 0.26 and 0.14 year-1 respectively. The exploitation rate (E) was computed 0.61. Confidence limit of Z was obtained 0.195-0.327 year-1 by Bootstrap method. At Monte Carlo simulation method, confidence limit of Z was calculated 0.169-0.289 year-1 with considering sampling error. Result of the present paper demonstrating that considering the uncertainty of population parameters of selected species could be useful for increasing the accuracy at stock assessment models.

Artificial reefs are used for increasing of aquatic biodiversity and stock rehabilitation in the word.  Fish Biodiversity was evaluated in artificial reefs that is located in Bandar –E-Salakh ((Qeshm island, concrete pipe (St1)), Bandar-E-Bostaneh ((Bandar-E- Lengeh) concrete pipe, St2) and St3 (Bandar-E-Bostaneh concrete pipe, pyramidal and Reef ball) in 20 meters. For this purpose, these selected underwater visual census method and randomized complete block design from 21Mar. 2017 to 20Mar.2018 seasonally. Measuring of biodiversity indices were obtained maximum of shanon- wiener (2.5), simpson (0.88), and margalf (8.22) indices in A.Rp,p,b, furthermore were concluded   the highest values of shanon- wiener (3.17), and margalf's richness (5.02) indices related to Heniochus acuminatus and Pomacanthus maculosus respectively . A normal log model is concluded from SHE analysis in between stations, also is resulted MacArthur’s broken stick model in species level, that is shown  more balanced distribution of resources among species of the community. In this study, was determined the role of artificial reefs in increasing of fish biodiversity and was found complexity of the physical structure for more efficiency in St3.

This study was conducted to determine density and distribution of commercial fishes (Argyrops spinifer- Carangoindes talamparoides and Saurdia tumbil)  by swept area method in Persian Gulf waters (Busher province). Sampling operation (27 hauls) was done by a trawler (Tabas class) with long 26 m and width 7.4 m in fishing season. Midwater trawl ned had a 72 m head rope and mesh sizes were 400 mm and 80 mm (stretched) in square and codend respectively. The averages of  CPUA  and biomass for Saurdia tumbil - Carangoindes talamparoides and Argyrops spinifer were estimated 218.21 ± 27.71 (kg/km2) and 8851.15 tons, 159.19 ± 22.11 (kg/km2) and 6457.02 tons, 171.75 ± 30.78 (kg/km2) and 6966.68 tons respectively. The results showed that the best depth of fishing effort for Argyrops spinifer and Saurdia tumbil was 30 m but for Carangoindes talamparoides was 20–30 m. The biomass of mentioned species in Motaf area represents the potential for commercial fishing in the spring. The results of this study indicated the water depth changes affected harvesting of two species Saurdia tumbil and Argyrops spinifer and had no significant impact on the species Carangoindes talamparoides.

The sampling of fishes and Macrobenthic were performed in Goharbaran Mazandaran province by selecting four stations at a depth of 5 meters and four stations at a depth of 10 meters a monthly basis from May 2013 to April 2014 and fish samples of coastal blade caught were used. During the study, a total of 565902 Macrobenthic invertebrates isolates belonging to 22 species of 9 families. Oligochaeta worms were identified at the level of the class and Polychaeta worms including 5 genera and species were. Crustacea with 16 species had the highest number of species than other species. Among the 6 species of fish, Rutilus kutum and Liza aurata were 73.05% and 24.67% of the total catch, respectively.The present study showed that Bivalvia, especially Cerastorderma, have a high relative importance for Rutilus kutum and the importance of Gastropoda, Crabs, Fish eggs, Filamentous alge was rare for this species. Also the most feeding of Cyprinus carpio, Liza auratus, and Liza saliens species were from Detrite. After Detrite, the most important food items for Cyprinus carpio were Bivalvia, Abra ovata, Gastropoda, Oligochaeta, Nereis, Fish eggs, Filamentous alge. After Detrite, the most important food items for Liza auratus were Foraminifera, Porifera and Balanus and for Liza saliens were related to Gastropoda, Bivalvia and Porifera. Due to the combination of  Macrobenthic invertebrates and the reduction of Bivalvia in the Goharbaran region, bait Food is not enough for the Rutilus kutum stocks. The present study showed that Bivalvia, especially Cerastorderma, have a high relative importance Rutilus kutum. The relative importance of Bivalvia in feeding carp was far more than other foods. In Ditritus, Mugillidae of fish in the present study was consistent with the results of other studies.

The study aimed to estimate the effect of ecological factors such as day and night on catch species composition in fishing landings in the perisan Gulf in May 2016. In this study, were catched about 34937.18 kg marine speceis and identified of 64 groups of species and family including 56 groups of bonyfishes, 6 groups of invertabrate, 2 groups of cartilage fishes. Meanwhile, the Bushehr, Hormozgan and Khuzestan province catched 22696.38, 10611.5 and 1629.3 kg respectively. The highest percentage of catches occuored in the stations sampled including Nemipteridae, Rey Fishes, Suaridae, S. Guttatus, Platycephalus Indicus and Sphyraenidae. In terms of catch weight Diagramma  pictum, Saurida tumbil and Rey fishes accounted for over 10% of the total catches. Result of catch per unit fishing effort (CPUE) for the Persian Gulf during day and night time showed that 22 groups of fishes have a significant difference, although there was no significant difference in the catches of 27 groups in day and night, which couse to have different patterns of migration during the day (lighted conditions) and night (dark conditions) and short sampling period of this research. According the little biological information during day and night for implementing and stock assessment models, The results of this study can be used to provide the target species in the trawl using during periods of light and dark.

Fish farming in recirculating aquaculture systems (RAS) has been expanding in the recent years, but the effects of water reuse are not well known. The aim of the present study was to compare the growth parameters, stress response and muscle stress- and growth- related gene expression of rainbow trout (Oncorhynchus mykiss) in open system (OS) versus water reuse system (WRS). For this purpose, young rainbow trout were studied in stocking density of 44 Kg/m3 and loading density of 1 L/min/Kg of fish in an OS (100% make-up water) and WRS (66% reused water) for 60 days. The results showed that water NH3 concentrations increased significantly in WRS compared to OS. In addition, final body weight in the WRS decreased by 6.5% compared to OS on day 60. No differences were observed between treatments in terms of fish length (total, fork, standard), specific growth rate and condition factor. In contrast, feed conversion ratio increased significantly in WRS respect to OS. Moreover, blood plasma cortisol levels as well as RNA expression of heat shock protein 70 (HSP70) in muscle increased significantly in WRS versus OS. However, no significant changes were found in muscle mRNA levels of insulin-like growth factor-1 (IGF-1) and myosin heavy chain (MHC) between the two treatments. In conclusion, water reuse protocol reduced some growth parameters, and induced measurable stress in fish in a manner not related to the expression of IGF-1 and MHC genes.

This study aimed to determine the fat requirement and effect of dietary fat levels on growth and body composition indices of hybrid Asp (Leuciscus aspius ♀) × Caspian Kutum (Rutilus frisii ♂). For this purpose, 252 fish with an average weight of 29.3 ± 5.8 g were introduced in a completely randomized design with six treatments each with triplicate groups. After two weeks of adaptation, fish were fed by 6 isonitrogenic diets (40% crude protein) with different fat levels including 7, 10, 13, 16, 19 and 22%, 3 times daily according to satiation for 56 days. Some growth indices including final weight, body weight  increase, specific growth  rate, condition factor, feed conversion ratio, protein efficiency ratio, hepatosomatic index and visceral index were considered for this study. The results showed significant differences in various levels of dietary fat in feed conversion ratio and protein efficiency ratio (P<0.05). There was no significant difference on body composition, total protein, total lipid, cholesterol and triglyceride (P>0.05). From the results of the present study, it can be suggest that increasing dietary fat levels up to 16% for better growth performance of this fish.

The effect of different levels of vitamins C and E on growth survival and blood factors were studied on common carp (Cyprinus carpio). 9 mixed diet containing 0, 200 and 400 mg / kg of vitamin C and0, 200 and 400 mg / kg vitamin E for 6 weeks were performed in triplicate. Total of 270 common carp with an average weight of 12.29 g were introduced into the 27 number of rearing tanks. At the end of the experiment the fish using cut stem tail vein blood samples were collected. The results showed that the different groups in terms of weight, length and survival observed difference is statistically significant (P < 0.05).The mean length and weight on the diet treated with 400 C + 400 E 6 mg / kg of vitamins. The results showed that the value of FCR, SGR, BWI, ADG and CF difference is not statistically significant (P > 0.05).The results of this study showed that the addition 400 C + 400 E mg / kg of the vitamin would be best growth and survival of common carp.