مجله علمی شیلات ایران
سال بیست و هفتم شماره 3 (پیاپی 107، امرداد و شهریور 1397)

The trawl fishing is used in the waters of the Persian Gulf and the Sea of ​​Oman to catch different kinds of aquatic animals by small and large trawler. One of the most important subjects is the rate and process of aquatic escapement during fishing and standardization of the nets. This research was designed to investigate fish escapement from different parts of the trawl. Sampling was carried out with four small pockets attached in different parts of the net. After six hauling operations, aquatic animals from all of the pockets were identified and measuring. Compare between pockets showed that T. lepturus with mean length of 72.5 cm had the highest value and S. insidiator with 5.2 cm length had the lowest one. In addition, S. tumbil with mean weight of 226 g had highest level while P. semisulcatus with the value of 1.7 g had lowest mean weight. Study of pockets showed highest escapements (64.52%) which was happened in the pocket close to cod end. Comparison between four pockets showed significant difference on amounts of aquatic escapement and the most escapements happened in the pockets close to cod end.

One of the important goals in the aquaculture industry is to increase fish production with the least stress from ammonia secretion. Yucca plant (Yucca schidigera) was composed of steroidal saponins, polysaccharides, and polyphenols, which have increase the intestinal flora activity to improving the digestive process, also great absorption capacity for harmful volatile compounds, such as ammonia and hydrogen sulfide. Therefore, the aim of this study was to evaluate the effects of different Yucca schidigera extract levels on the Cyprinus carpio growth, feed performance, body composition and culture water quality for 60 days. Experimental treatments were designed which include: T1 (control without extracts), T2, T3 and T4 treatments (containing 0.5, 1 and 1.5% Yucca extract respectively). In a completely randomized design, 360 Common carp fish with weight of 2.40±0.04 g and length of 5.47±0.05 cm were reared in twelve 40-L plastic tanks. Different levels of extract were sprayed on commercial food and consumed at 4 times daily. There was significantly higher final body weights in T4 (p

The objectives of the present investigation were to study the bioaccumulation of Aldrin, Diazinon and Endrin pesticides in the edible muscle tissues of Tinca tinca, Rutilus frisii kutum, Carassius auratus, Cyprinus carpio, Silurus glanis and Esox lucius that were caught at various stations in the west, east and center of the Anzali Wetland and to compare the results with the standards of the World Health Organization (WHO). The concentration of organochlorine pesticide was determined using Gas Chromatography (GC) equipped with an electron capture detector. The concentration of organophosphorus pesticide was determined using Gas Chromatography/Mass Spectrometry (GC/MS). The highest concentration of Diazinon was detected in Esox lucius from the wetland east station (20.25 ppb). Significant differences were not observed in the amounts of Diazinon and Aldrin pesticides in the muscles of fish samples in various stations (P>0/05). The highest amounts of Endrin were observed in the muscle of Cyprinus carpio from the wetland east and west stations which were significantly different compared to that of other fish species (P

Prebiotics are non-digestive food ingredients which beneficially affect the host by selectively stimulating the growth and activity of health-promoting bacteria in the intestinal tract. This experiment was conducted to evaluate the effect of dietary supplementation of galactooilgosaccharide on the growth performances, survival and several of innate immunity parameters of rainbow trout (Oncorhynchus mykiss) larvae for 60 days. In this experiment, 360 of larvae (with average weight of 0.13±0.01g) in 4 treatments and 3 replicates (n=30 in each replicate) in a completely randomized design was divided and fed with diets containing 0, 1, 2 and 3 percent galactooligosaccharide respectively. The present results showed that highest WG, SGR and PER were observed in the diet containing 2 and 3 percent of dietary galactoologosaccharide which had a significant difference compared with other treatments (p

This study was conducted to determine heavy metals (Cu, Mo, As, Hg) in fish species of Aras River (East Azerbaijan) at four stations (From Julfa to 25km after Nourdos border) during four seasons from 2015 to 2016. Thirty eight specimens of fish were collected by using of electrofishing as the main method for sampling. The amount of heavy metals were measured by using an atomic spectrophotometer in the muscle tissue of specimens.Bioaccumulation factor were also calculated for each species. The amount of bioaccumulation factor for molybdenum was the highest and the arsenic had the lowest amount. The highest concentration of copper was in Barbus lacerta with a mean of 13.6 ± 11.3μg /g dry weight and for the molybdenum, Alburnoides bipunctatus had the highest mean concentration (11.7±4.9) μg / g dry weight. The average concentration of mercury (13.1 ± 1.5 μg / kg dry weight) was highest in Alburnus alburnus. Regarding the arsenic elements, as it was analyzed in a small number of specimens, the highest concentrations were recorded in Alburnoides bipunctatus. According to ANOVA, there were a significant difference between mean concentration of copper in different species(p

In this study, the effects of Tarragon and Savory essential oils on oxidative stability of ready-to-eat shrimp (Metapenaeus stebbingi) during three months at frozen storage were investigated. Samples were treated with Tarragon and Savory essential oils and cooked by different cooking methods (frying, oven baking and steaming). Butylated hydroxytoluene (BHT) was used as a reference to compare antioxidant activities. During frozen storage, fat hydrolysis was evaluated through measuring free fatty acid value and oxidation products were measured via peroxide value and thiobarbutiric resistance substance. At the end of storage, the highest amount of free fatty acids (following the control) was observed in steamed savory treated samples (3.2% oleic acid) and the lowest amount in Savory and Ttarragon fried samples (1.11 and 1.75% oleic acid). Following BHT, the lowest amount of peroxide value was obtained from steamed shrimps treated with tarragon (0.92 meq/kg of fat). Also, thiobarbutiric acid values in fried and oven baked samples containing Savory essential oil (0.55 and 0.42 mg MA/kg of fat) was higher than samples containing Tarragon essential oil (0.44 and 0.38 mg MA/kg of fat). The results of the present study indicated that Tarragon and Savory essential oils retarded the oxidation and samples treated with Tarragon essential oil showed slower hydroperoxide and malonaldehyde formation than those of Savory-treated or the untreated samples. The best storage period of the fried, oven baked and steamed products treated with Tarragon and Savory were 1, 2 and 3 months, respectively.

In this study, mouth morphological development and the importance of size of pellet food at the onset of exogenous feeding, with respect to mouth size from hatching through 60s day after hatching (DAH), were studied in larval and juvenile Vimba bream (Vimba vimba). The samples were randomly taken at 1-8 DAH, then with 2, 5, and 10 days intervals until 60 DAH (being released into the sea). Morphological examinations of mouth were followed using SEM. The length of upper and lower jaws as well as the size of mouth gap at 45° and 90° were calculated to estimate the size of pellet food. The larval mouth opened at 1 DAH and filiform papillae, and lips began to form at 2 DAH. The first taste buds developed at 3 DAH. The larval mouth developed a crescent shape at 4 DAH and the structure of papilla became clear. A number of neuromast cells were observed around the mouth at 8 DAH. Finally, it can be concluded that with the onset of exogenous feeding, Vimba vimba larvae is probably able to ingest and digest 110 µm pellet food since 8 DAH. Thus, since 20 DAH until the end of larval rearing period, formulated diets can only be used.

In this study, the effect of dietary phytase and wheat bran on some growth performances and phosphorus absorption function of common carp fry for 60 days was assessed. A total number of 180 common carp fry (20±1 initial weight) was randomly distributed in six experimental groups including, control group without any additive (basal diet), T1 (basal diet� IU/Kg phytase), T2 (basal diet IU/Kg phytase), T3 (basal diet g/Kg wheat bran), T4 (basal diet g/Kg wheat bran) and T5 (basal diet� IU/Kg phytase g/Kg wheat bran). The highest body weight (150.02±4.76 g), specific growth rate (0.65±0.19%), and condition factor (3.20±0.26%) was observed in T5 (p

The effects of nitrate (750-2250 mg/L), phosphate (20-60 mg/L) and photoperiod (8-24 h) on the growth, chlorophyll content and lipid yield of Chlorella vulgaris were studied using central composite design (CCD) method. The second-order quadratic model was used to predict the effects of input variables on the output responses and the results were verified by F test, ANOVA and regression analyses. Results showed that maximum growth (255.88 ×106) as well as highest chlorophyll content (15.34%) were observed at 16 h of light, 1500 mg/L of nitrate and 40 mg/L of phosphate concentration. Also, condition of 24 h of light, 750 mg/L nitrate and 20 mg/L phosphate concentrations resulted in maximum percent of lipid content (17.74%). The optimization of culture condition for simultaneous achievement of highest levels of growth, chlorophyll and lipid content were investigated.

The purpose of this study was to investigate the effects of dietary supplements of Pediococcus acidilactici bacteria and Agaricus bisporus mushroom powder separate and combined (combined supplement) on the skin mucosal immune indices of common carp (Cyprinus carpio) in exposure to silver nano-particles. For this purpose, 180 fish with mean weight 29.6±0.4 g were fed in four treatments: bacteria (1 g/kg of diet), mushroom powder (10 g/kg of diet), combined bacteria and mushroom powder (1 and 10 g/kg of bacteria and mushroom) supplements and control (nutritionally non-supplemented) treatments and each treatment with 3 replicate (15 fish per replicate) for 60 days. After the end of the feeding period, the fish were exposed to sub-acute concentration of nano-silver (1 mg/l) for 14 days. Sampling of skin mucosa was performed to evaluate the immune-related parameters on days 1, 7 and 14 (5 sampling per replicate). Results showed that activity of lysozyme, alkaline phosphatase enzymes, soluble protein and total immunoglobulin in diets containing dietary supplements had a significant difference in nano exposed groups with control treatments (p

The aim of this study was to determine the qualitative characteristics of ready-made fish paste made from minced meat (Clupeonella cultriventris) and silver carp (Hypophthalmichthys molitrix) and its shelf-life at a refrigerated temperature.This compilation was performed in five treatments including amounts 100, 75, 50 and 25 percent of processed fish meat were cured. The treatments were packed in heat-resistant glass after pasteurization. Samples were stored at 4 oC for 40 days.The amount of TVB-N in the experimental treatments during the course of the change was increased that this factor varied between15.25-31.25 mg/100 g of meat in experimental treatments. This factor was in the 100% rolled silver carp treatment until the end of the shelf life in the standard range. The amount of tybarbibacteric acid increased during storage period varied between 0.13-2.11mg malondialdehyde/1000g in experimental treatments, but this factor was in the 100% treatment of silver carp paste after the end of the maintenance period in the standard range (less than 1.8 mg/100gr), in other treatments, after 30 days, was more than standard limitation. The pH changes in treatments did not significantly decrease (P>0.05), this factor varied between 5.05 to 5.93 in the experimental period. Total bacterial counts, psychrophilic bacteria and coliform and molds were not observed in experimental treatments during storage period. Microbial contamination was not observed during the storage period in the refrigerator in the experimental treatments. The taste and texture in silver carp treatment (100%) were better than other treatments. The ash, protein and fat in 5 treatments did not significantly change during storage (p>0.05). The moisture content was not significantly increased in all five treatments during storage (p>0.05). Results showed treatment of processed carp (100%) was better than other treatments (p<0.05).

The effect of different levels of herbal supplement of Cumin powder (Cuminum cyminum) on growth, survival and carcass composition of the Litopenaeus vannamei was evaluated in the summer of 1395 for 56 days at the Persian Gulf Aquaculture reproduction and reconstruction center. For this purpose, four groups of shrimp with an average weight of 3.45±0.3 g in 300 liter fiberglass tanks with a density of 60 shrimp per tank, with different levels (0.5, 1 and 1.5 percent) was supplemented. The Cumin powder was fed with 3 replicates. At the end of the period, growth indices (average body weight gain, body weight gain, specific growth ratio and feed conversion ratio), survival rate, and chemical composition of these treatments were compared with control treatment. The results showed that the treatment with 1% Cumin powder had higher growth indices and better survival than other treatments (p<0.05). In the case of carcass biochemical analysis, the results showed a significant increase in protein and fat content and a significant decrease in moisture content in Cumin powder treatments compared to control (p <0.05). The results of this study showed that 1% Cumin powder in diet could be used to improve the growth performance, survival and quality of the carcass composition of white shrimp (Litopenaeus vannamei).

Efficiency of various meshes of gillnet and trolling gear was investigated for catching kingfish (Scomberomorus commerson) in coastal waters of Sistan and Baluchestan province in 2007. In gillnets with mesh sizes between 57 to 110 mm and netting of monofilamnet and multifilament, the size distribution of kingfish ranged between 40 to 78 cm of fork length, which all specimen caught were immature. In mesh size of 146 mm and 171 mm, the length range of the species was larger, in which the frequency of immature fish for the respective mesh sizes was 19 and 11. In general, most fish was captured by wedging in the all mesh sizes. The size range of kingfish captured by the trolling was between 52 and 147 cm, of which more than 50 percent of caught fish were immature. The proportion of kingfish catches in the gillnets of 57-110 mm mesh sizes is about 13% of the total catch composition, for which the mesh sizes are considered as the dominant gillnets for capturing the species in this area. The conribution of kingfish catches in 133, 146, and 171 mm mesh sizes was 1.1, 52.3 and 18.9% respectively, with a 146-mm mesh size is considered as a dominant gillnet for this species. The implementation of the ban on the use of 57 to 110 mm mesh sizes for exploitation of kingfish is mandatory, which the mesh size of 146 mm and above seems to be appropriate for responsible fishery of the species. However, recommendation of standard mesh size needs to be re-examined in field trials.

Due to the inevitable achievement of nanoparticles to aquatic ecosystems, the limitation of existing reports, and the inadequate understanding of their possible biological reactions with aquatic organisms, this study in the pioneering step was aimed to toxicity assessment of aqueous suspension of chemical magnetic nanoparticles (Fe3O4) in zooplanktonic species such as barnacle larvae Amphibalanus amphitrite (sea water index) and rotifer Brachionus rotundiformis (fresh water index). For this purpose, serial concentrations (0, 10, 50, 100, 200, 500 mg / l) of magnetite nanoparticles were prepared in 24 well plates with 5 replicates. After that, the zooplanktons (50 barnacle nauplii and 20 neonate rotifer to each well) were introduced to plates and the sensitivity of the samples were evaluated for the toxicity of nanoparticles at a time interval of 12-48 hours. The results of this study showed that the toxicity effects of chemical magnetite nanoparticles on barnacle nauplii larvae and neonate rotifer were increased with increasing time and concentration of magnetite nanoparticles. Differences between control and treatment groups were significant (P<0.05). However, after 48 hours of exposure, the mortality rate at the highest concentration (500 mg/l) in barnacles was 62% (LC50= 466.5 mg/l) and in rotifer 34% (E50>1000 mg/l). Regardless of species variation in barnacles and rotifers, according to the results, magnetite nanoparticles are in the group of non-toxic contaminants for these zooplanktonic organisms.

The vitellogenin gene expression can be altered by some estrogenic plant compounds like Genistein and β-sitosterol. Therefore, the measurement of vitellogenin gene expression can be used as an indicator to determine their effect on reproductive performance of aquatic animals. In order to evaluate the effects of genistein and β-sitosterol on the expression of vitellogenin gene in the liver and ovary of Rutilus frisii Kutum, the fish were separately exposed to 3 levels of genistein and beta-sitosterol (500, 50 and 10 ng/L). After 21 days, the RNA extracted and expression of vitellogenin gene in both the liver and ovary was investigated by Real-time PCR. The results showed the level of vitellogenin gene expression in fish exposed to genistein was higher in liver than control and β-sitosterol treatment. This difference was not observed in the ovarian tissue. Because the main site of vitellogenin synthesis expressed liver and it was controlled by endogenous estrogen (E2), so, it seems phytoesterogenic compound such as genistein has been able to increase the relative expression of this gene in fish Exposed to 500 ng/L.

A 30-day research was conducted to evaluate the effects of different feeding rate (formulated diet) (2, 4, 6, 8 and 10% of wet body weight/day) and also fresh food (20% of wet body weight/day) on growth performance and feed utilization of Sparidentex hasta fry in nursery phase. Growth performance including final weight and specific growth rate (SGR) significantly increased with increasing feeding rate (p<0.05). The relationship between SGR (% per day) and ration level (% per day) was an asymptotic curve described as SGR = 0.2809X+1.4191. Feed efficiency ratio (FER) decreased significantly with increasing ration levels, and the relationship between FER and ration level (% per day) described as FER = -0.0586X+1.3184. Hepatosomatic index significantly increased with increasing feeding rate (p<0.05). Based on the above results, it may be concluded that a ration size of 8% of body weight per day is optimal for good growth and feed conversion efficiency of juvenile S. hasta in nursery phase.