26 research outputs found

    A survey on some biological aspects of spiny lobster Panulirus homarus for optimizing fishing season in Sistan - o – Baluchestan province

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    Research project was conducted on some biological aspects of lobster in Oman Sea in the years1385-86. During the project some parameters such as length distribution, spawning peak, length (Carapace) at first maturity, the length at which 50% of the lobsters were found to be mature sexually, sex ratio, relative frequency index and population dynamics parameters were examined. Quantitative factors and catch composition of lobster including the amount of catch in terms of weight and number of ovigerous-female, under-sized specimens and so were compared by monthly. According to the results of present study caught specimens were male with carapace length of 22 and 110 mm respectively. The smallest ovigerous female was taken as 46mm CL when length at first maturity was estimated to be 69-70mm. the male: female ratio was 0.7: 1.3 for the whole year. A closed fishing season for the species is proposed during spring and September and October in Oman Sea. A large amount of the catches for the all sampling months came from the under-sized specimens, consist of 50 to 85% of the total catch. Therefore, presence of these small length groups have direct effects on time of closing season. Population dynamics parameters were calculated as follows: K=0.57 year, L∞= 103mm and Ǿ = 8.69. Total mortality (Z), natural mortality (M) and fishing mortality (F) coefficients were calculated as 2.73, 0.87 and 1.86, respectively. Exploitation ratio for the whole population was 0.681, indicating an overexploitation of the species. Based on the available data, the recruitment pattern for lobster was obtained for two season including spring (major) and autumn (minor). Catch per unite effort (CPUE) was calculated as 0.908 kg/Cage/day which was higher in comparison with two other areas including Ramin and Chabahar. Examination of CPUE for a 10-year period showed a decreased trend and the reduction for the year 1386 was about 30% when compared to the data from the year 1375. Moreover, the mean length during 1369-70 to 1385-86 (present study) decreased for the three areas including Pozm, Ramin and Chabahar, so that the carapas length decreased up to 10 mm in length. This sudden decrease in mean length during the 10-year period should be considered as a serious precariousness for sustainable exploitation of lobster in Oman Sea along Sistan and Baluchistan province

    Investigation on feasibility polyculture of Litopenaeus vannamei with Mugil cephalus in earthen shrimp ponds

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    This study was conducted in order to optimizing of the biological condition and enhancing of the harvest efficiency for cultured shrimps of Guater site. Experimental design was consisted of three treatments and each treatment with three replications (totally 9 ponds with 600 m^2 area for each pond). After preparing and watering of ponds, the ponds was stocked with shrimp post larves in a density of 0.007±0.001 g (or 20 numbers per m^2) per m^2. After 35 days, the fingerlings of gray mullet were released to shrimp ponds in densities of 0/100 m^2 (T1/), 2/100 m^2 (T2) and 4/100 m^2 (T3). During experiment, the physicochemical parameters of water (temperature, O_2, pH, water transparency and salinity) were measured daily for two times (morning and afternoon). Also, the nitrate, nitrite, ammonia, phosphate and silicate concentrations and BOD5 as well as chlorophyll (a), phytoplanktons and zooplanktons were measured every 15 days one time. To determine the organic values of the bottom sediment of the ponds, monthly sampling was conducted. Health status of shrimps was investigated monthly too. Growth rate, mean weight, survival value, Food conversion ratios (FCR) and total shrimp harvest (Kg) were measured after 107 days rearing in ponds. ANOVA analysis showed significant differences between treatments. The highest (212 Kg, 3533 Kg; weight mean was18.4 g for each shrimp) and lowest (187 Kg, 3116 Kg; weight mean was16.23 g for each shrimp) of harvested shrimps were yielded in T3 and T1 respectively. There was not significant differences between treatments in terms of survival rate (P>0.05). After 107 days rearing, the highest (1.27 0.2) and lowest (1.2 0.1) of FCR were observed in T_3 and T_1 respectively. Although, there were no significant differences between T_2 and T_3 in ammonia, O_2, Total organic material, pH and BOD5, but, T_2 and T_3 had significant differences with T_1 in these parameters. In this study, 27 genus of phytoplanktons belonged to Diatoms (Bacillariophyceae), blue-green algal (Cyanophyceae) and dinoflagellates (Dinophyceae) were identified. Diatoms with 20 genus had more abundance than dinoflagellates (6 genus) and blue-green algal (1 genus). Also, 7 orders of zooplanktons including copepod, mollusks, nauplius of crustacean and rhizopoda were identified. Health investigation of T1 (without shrimp) showed more pathogenic pollution (parasites and bacteria) than in treatments with shrimp. In this regard, among bacteria, the Vibrio genus (V.Alginoliticus and V.Fluvialis) had more abundance and among parasites zoothamnium sp and Epistylis sp were identified which more abundance was for zoothamnium sp. In conclusion, our results concluded that mixed culturing of white shrimp and grey mullet in optimum densities is possible and is caused more production of shrimp

    The study of fluctuation of large pelagic stock (yellowfin tuna, skipjack tuna, longtail tuna, Narrow-barred Spanish mackerel) in order to optimum exploitation in the Persian Gulf & Oman sea

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    The study of fluctuation of large pelagic stock (yellowfin tuna, skipjack tuna, longtail tuna, Narrow-barred Spanish mackerel ) in order to optimum exploitation in the Persian Gulf & Oman sea This study was carried out from 2005-07 in order to acquire some biological characteristics and population dynamic parameters for stock management and responsible fisheries. Thunnus albacares (yellowfin tuna), katsuwonus pelamis (skipjack tuna), Thunnus tonggol (longtail tuna) and scomberomorus commerson (Narrow- barred Spanish mackerel) were sampled. In total, length frequency of 9345 specimens of yellowfin tuna were analyzed. Size range was 37-172 cm. Teleost fishes were the most dominant prey species observed in this study (42%), Occurrence of Potunus Pelagicus was found to be the second (28%).Sthenoteuthis oualaniensis (22%), Natosquilla (5%) and octopus (3%) also were identified in the gut content of the yellowfin tuna. Length of maturity (50%) of yellow fin tuna was estimated 77.2 cm and spawning season was started from May. 8443 specimens of skipjack with size range of 32-90 cm were sampled. 48% of food items were teleost fishes. Squid and shrimp were also identified. Spawning season was begun from June. Growth parameters & fishing mortalities of yellow fin tuna and skipjack tuna were also estimated. Size range if longtail tuna was from 26-125cm Length infinity was estimated 132.3 cm with growth parameter of 0.35 per year. In total 10451 specimens of narrow- barred Spanish mackerel were sampled. Size range was from 20-164 cm. Teleost fishes were the most dominant prey species observed in the study (91.3%). Crustaceans (0.6%) and Indian squid (0.2%) also were identified in the specimens. Length maturity (50%) was estimated 83.6cm

    Growth performance and age composition of Salmo trutta caspius in Iranian part of Caspian Sea

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    The aim of this project is to study the growth and age structure in the Caspian trout, comparison with other coldwater species and check the trend of these parameters in recent years. This study was conducted during 2013 till 2015. Totally, 43 specimens for back calculation and 101 specimens for biometrical study of the Caspian trout have been caught in two month period. Biometric parameters such as length, weight and age of the fish were recorded. Base on Back calculation method in 1393, the average length of fish at ages 1, 2 and 3 years old were 18.98 ± 3.5, 30.5 ± 7.24 and 41.7 ± 9.1 cm. So these age groups are under the adult age and don’t approaching to near the beach and rivers for spawning behavior. Therefore, these length groups cannot be observed in catch composition. The result showed, the mean of gonad weight in this fish was about 11 percent of total weight and number of eggs per gram of gonad calculated about 10.8 numbers. Minimum age and maximum age of this species determined 4 years and 7 years (mean = 5.6) and the most frequency allocated to 5 age group and the frequency of 6 and 7 years has been remarkable. The average length of salmon was 69.2 ± 6.2 cm (minimum 57 and maximum 81 cm) and the average weight was measured 3323 ± 677 g (2400 to 5600 g) in the catch composition. Growth parameters such as k, L_∞ and ø’ was measured 0.18, 104 cm and 3.289 respectively. The amount of b for relation length and weight was 2.9 which imply negative allometry. L_∞ and growth coefficient (K) on the Caspian trout were acceptable range, that it shows good growth the fish in the sea water. Most of the fishes were catched from Cheshmehkileh River. As at present Shilat uses just the broods of the Tonekaboon region for restocking of this species, we recommend using the broods of the western region separately for rehabilitation of the stocks of this region

    Biomass estimation of demersal resources in the Persian Gulf and Oman Sea by swept area method

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    Regarding to monitor of demersal resources in the Persian Gulf and Oman Sea, and also biomass and CPUA estimation of them, ten research cruises were carried out by using R/V Ferdows-1 equipped with bottom trawl, covering the area from 49º 00´ E in the west (north-west Persian Gulf) to 61º 25´ E in the east (borderline with Pakistan) from 2012 to 2014 The study area was stratified into 17 strata (A to Q) of which 10 strata (A to J) were in the Persian Gulf and 7 strata (K to Q) were in the Oman Sea, covering the depths of 10-50 m in the Persian Gulf and 10-100 m in the Oman Sea. A total of 316 stations were randomly selected and the biomass and CPUA were estimated by swept area method during this three years period, the strat A and B weren’t covered. The comparison between two regions indicated that the percentage of density of demersal fishes in the Persian Gulf during years 2012, 2013 and 2014 were 1.0, 1.4 and 1.6 times more than the Oman Sea and totally 50-60% of total biomass was found for the Persian Gulf. Also a comparison among 17 strata the highest biomass was found for K region (Sirik to Jask) in the Oman Sea in 2012 & 2014; and C region (Genaveh to Bordkhoon) in 2013 in the Persian Gulf. The same comparison was done for CPUA of commercial, non-commercial and total in both water bodies and it was found that in years 2012 to 2014 the region K (Sirik to Jask) in the Oman Sea and Stratum Q (Bersi to Gwatr) had the highest value of CPUA. On the contrary, the stratum M (Biahi to Galak estuary) showed the lowest value of biomass for both commercial and non-commercial fishes. With review the mean CPUA in different depth layers for years 2012, 2013 and 2014, it was concluded that in the Oman Sea with increasing the depth, the mean CPUA is decreased and the lowest CPUA belongs to depths of 30-50 m The comparison between commercial and non-commercial groups in both ecosystems, it concluded that the density of commercial species were higher than non-commercial ones; and for years 2009, 2010 and 2011 the commercial species consist of 63.4, 65.0 and 59.7 % of total biomass. In all years the Persian Gulf indicated higher values than the Oman Sea. The most abundant fishes were Rays, Ribbon fishes, Carangids, Grunts, Japanese threadfin bream, Lizardfish and Barracuda for both Persian Gulf and Oman Sea

    BIOLOGICAL INVESTIGATION OF TIGER-TOOTHED CROAKER, OTOLITHES RUBER, IN OMAN SEA ALONG SISTAN AND BALUCHISTAN PROVINCE

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    During the years 2003-2004, biological aspects of Tiger-toothed Croaker, Otolithes ruber, was investigated in Oman Sea along Sistan and Baluchistan Province. Based on the frequency of developed maturity stages (IV,V), a prolonged spawning activity extending from August to March was determined for 0. ruber. The Gonadosomatic Index (GSI) suggests two peaks which a minor one in October and a major one in March-April. Comparison of Hepatosomatic Index (HI) and Condition Factor (Kn) with the spawning peak indicated a reverse relationship. According to length at first maturity (Lm50%=40cm) data and exploitation of fish at lengths more than 40cm, the stretched optimum mesh size of nets was calculated at 100mm. Analysis of stomach food items, showed that fish group dominated the diet (80%), of which Anchovy accounted for 40% of the total frequency. We estimated the exploitation rate of the fish at E= 0.6. The length infinity (L¥), natural mortality (M), fishing mortality (F), total mortality (Z) and Growth Coefficient per year (K) were calculated at 68.6, 0.69, 1.05, 1.74 & 0.35 respectively. The relationship between length and weight of the fish in the province was also determined. The parameters a, b and r (correlation coefficient) of the relationship were 0.0085, 3.0435 and 0.98 respectively

    EVALUATING THE EFFECTS OF PERIOD OF STRUCTURES ON SOIL-STRUCTURE INTERACTION

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    The Thirteenth East Asia-Pacific Conference on Structural Engineering and Construction (EASEC-13), September 11-13, 2013, Sapporo, Japan

    Comparing the effect of low and high emittance on synchrotron radiation and beamline design

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    In this paper, we have discussed about the role of two emittance values suggested for Iranian Light Source Facility (ILSF) (3.278 and 0.476 nm.rad) on different radiation features of the synchrotron light sources (bending magnet, shaker and oscillator) such as spot size, divergence of the beam on light spot, brilliance and important quantities in beamline design such as photon cross-section, optical element sizes and energy resolution &nbsp

    Apelin�13 protects against memory impairment and neuronal loss, Induced by Scopolamine in male rats

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    The present study aimed to evaluate the effects of Apelin�13 on scopolamine�induced memory impairment in rats. Forty male rats were divided into five groups of eight. The control group received no intervention; the scopolamine group underwent stereotaxic surgery and received 3 mg/kg intraperitoneal scopolamine. The treatment groups additionally received 1.25, 2.5 and 5 µg apelin�13 in right lateral ventricles for 7 days. All rats (except the control group) were tested for the passive avoidance reaction, 24 h after the last drug injection. For histological analysis, hippocampal sections were stained with cresyl violet; synaptogenesis biochemical markers were determined by immunoblotting. Apelin�13 alleviated scopolamine�induced passive avoidance memory impairment and neuronal loss in the rats� hippocampus (P<0.001). The reduction observed in mean concentrations of hippocampal synaptic proteins (including neurexin1, neuroligin, and postsynaptic density protein 95) in scopolamine�treated animals was attenuated by apelin�13 treatment. The results demonstrated that apelin�13 can protect against passive avoidance memory deficiency, and neuronal loss, induced by scopolamine in male rats. Further experimental and clinical studies are required to confirm its therapeutic potential in neurodegenerative diseases. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature

    An efficient automated incremental density-based algorithm for clustering and classification

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    Data clustering divides the datasets into different groups. Incremental Density-Based Spatial Clustering of Applications with Noise (DBSCAN) is a famous density-based clustering technique able to find the clusters of variable sizes and shapes. The quality of incremental DBSCAN results has been influenced by two input parameters: MinPts (Minimum Points) and Eps (Epsilon). Therefore, the parameter setting is one of the major problems of incremental DBSCAN. In the present article, an improved incremental DBSCAN accorded to Non-dominated Sorting Genetic Algorithm II (NSGA-II) has been presented to address the issue. The proposed algorithm adjusts the two parameters (MinPts and Eps) of the incremental DBSCAN via the iteration and the fitness functions to enhance the clustering precision. Moreover, our proposed method introduces suitable fitness functions for both labeled and unlabeled datasets. We have also improved the efficiency of the proposed hybrid algorithm by parallelization of the optimization process. The evaluation of the introduced method has been done through some textual and numerical datasets with different shapes, sizes, and dimensions. According to the experimental results, the proposed algorithm provides better results than Multi-Objective Particle Swarm Optimization (MOPSO) based incremental DBSCAN and a few well-known techniques, particularly regarding the shape and balanced datasets. Also, good speed-up can be reached with a parallel model compared with the serial version of the algorithm. © 2020 Elsevier B.V
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