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用颗粒饲料驯化养殖瓦氏黄颡鱼鱼种,夏花鱼种的放养密度为10450尾/667m2,其中瓦氏黄颡鱼、鲢、鳙和鲫的鱼种分别放养10000、200、200和50尾。经132d饲养,平均单产为691.9kg/667m2,其中瓦氏黄颡鱼589.1kg,平均规格60.3g,成活率97.7%;鲢39.3kg,平均规格213.1g,成活率92.3%;鳙49.3kg,平均规格257.5g,成活率95.8%;鲫14.2kg,平均规格316.5g,成活率90.0%。平均每667m2池塘投喂颗粒饲料1400kg,平均饲料系数2.32(其中瓦氏黄颡鱼饲料系数为2.38)。 相似文献
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为充分利用养殖水体,提高综合养殖效益,河北省唐山市丰南区迎春水产养殖合作社2019年利用1口面积为0.533 hm2的池塘,进行了加州鲈与黄颡鱼套养试验,共收获加州鲈8126 kg,黄颡鱼825 kg,加州鲈平均规格525 g/尾,黄颡鱼平均规格240 g/尾,获毛收入34.5665万元,养殖利润12.0417万元。试验证明,加州鲈与黄颡鱼套养技术饲料系数低,发病率低,养殖效益明显。 相似文献
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上海郊区翘嘴鲌、黄颡鱼池塘高效混养技术 总被引：1，自引：1，他引：0
为探索翘嘴鲌、黄颡鱼新型养殖模式,于2015-2016年在上海市青浦区某标准化水产养殖场进行了翘嘴鲌、黄颡鱼池塘混养试验,并搭养适量的鲢、鳙,综合运用精准投饲、水质调控等技术。试验结果:翘嘴鲌平均亩产(15亩=1 hm~2,下同)556.5 kg,平均规格610.2 g/尾,成活率91.2%;黄颡鱼平均亩产1 318.4 kg,平均规格128.5 g/尾,成活率85.5%。平均亩产值3.85万元,平均亩利润1.00万元。试验获得成功并取得了较好的经济效益,可以作为一种高效混养模式进行推广。 相似文献
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为探索翘嘴鲌、黄颡鱼新型养殖模式,于2015—2016年在上海市青浦区某标准化水产养殖场进行了翘嘴鲌、黄颡鱼池塘混养试验,并搭养适量的鲢、鳙,综合运用精准投饲、水质调控等技术。试验结果:翘嘴鲌平均亩产(15亩=1 hm2,下同)556.5 kg,平均规格610.2 g/尾,成活率91.2%;黄颡鱼平均亩产1 318.4 kg,平均规格128.5 g/尾,成活率85.5%。平均亩产值3.85万元,平均亩利润1.00万元。试验获得成功并取得了较好的经济效益,可以作为一种高效混养模式进行推广。 相似文献
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经197 d培育,鱼种成活率70.7%,单产18.28 kg/m2,平均规格17.25 g/尾,最大个体25 g,最小个体10 g,饵料系数1.34。鱼种经170多d养殖,成活率80%,产商品鱼9 454 kg,单产32.8 kg/m2,平均规格77.5 g/尾,最大个体174 g,最小个体69.5 g,饵料系数2.24。总产值226 896元,折合788元/m2;净产值128 425元,折合445元/m2。投入产出比1∶2.3。 相似文献
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为了对4种不同开口大小的六边形开口方形人工鱼礁在4种迎流角度下数值模拟和水槽模型试验的阻力系数进行对比验证,分别利用水槽模型和数值模拟试验方法对4种不同开口比（γty=0.0625,0.14,0.25,0.39）六边形开口方形人工鱼礁在4种迎流角度（θ=0°,15°,30°,45°）状态下的阻力进行测定,并计算两种方法的阻力系数。结果表明：（1）在数值模拟和水槽模型试验中,人工鱼礁模型阻力均随着开口比的增大而减小;礁体迎流角度的变化可改变礁体阻力,且在4种迎流角度下,人工鱼礁阻力在θ=30°时最大。（2）人工鱼礁数值模拟与水槽模型试验中,当θ为15°、30°和45°时,阻力系数均随着开口比的增加而增加,具有明显的线性关系,且阻力系数在迎流角度θ=30°时最大。（3）数值模拟与模型试验阻力的相对误差在0.12%~17.18%,平均误差7.43%;礁体阻力系数的相对误差在0.03%~14.64%,平均误差5.26%。阻力及阻力系数误差均在20%以下。水槽模型试验与数值模拟阻力和阻力系数相关系数R分别为0.99和0.80,P<0.001,具有极强的相关性。因此,利用数值模拟精细化研究人工鱼礁水动力性能是可行的。 相似文献
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Michael H. Meeuwig Christopher S. Guy Wade A. Fredenberg 《Ecology of Freshwater Fish》2011,20(2):315-325
Abstract – Bull trout, a species of char listed as threatened under the US Endangered Species Act, have been displaced from portions of their historic range following the introduction of nonnative lake trout. It has been suggested that competitive exclusion as a result of trophic overlap between bull trout and lake trout may be the causal mechanism associated with displacement of bull trout. This study used stable isotope data to evaluate trophic relationships among native bull trout, nonnative lake trout and other fishes in seven lakes in Glacier National Park (GNP), Montana. Bull trout and lake trout had greater δ15N values relative to other fishes among lakes (δ15N ≥ 3.0‰). Lake trout had greater δ15N values relative to bull trout (δ15N = +1.0‰). Bull trout had greater δ13C values relative to lake trout in six of the seven lakes examined. Although both bull trout and lake trout had greater δ15N values relative to other fishes within lakes in GNP, differences in δ15N and δ13C between bull trout and lake trout suggest that they are consuming different prey species or similar prey species in different proportions. Therefore, displacement of bull trout as a direct result of complete overlap in food resource use is not anticipated unless diet shifts occur or food resources become limiting. Additionally, future studies should evaluate food habits to identify important prey species and sources of partial dietary overlap between bull trout and lake trout. 相似文献
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Yukihiro Kitade Michiko Nakamura Hirotoshi Endo Satoru Fukuda Kazuyoshi Kuwano Naotsune Saga 《Fisheries Science》2006,72(3):639-645
ABSTRACT: A cDNA ( PyARP4 ) containing an open reading frame for a protein of 573 amino acids was identified in the marine red alga Porphyra yezoensis . The conceptual PyARP4 protein exhibits significant similarity to actin-related protein (ARP) 4 in the terrestrial plant Arabidopsis . Comparison of the deduced amino acid sequence showed moderate sequence identity (30%) to a conventional actin in P. yezoensis , as seen in comparisons between ARP and conventional actins of other organisms. A putative bipartite nuclear localization signal and an actin motif were found within the PyARP4 amino acid sequence. In a phylogenetic analysis, the PyARP4 was found to cluster with the ARP4 of other organisms. The expression level of PyARP4 did not change significantly among four developmental stages of life cycle and was lower than that of a conventional actin. This cDNA therefore may serve as a useful internal standard in gene expression analyses of differentially expressed genes in P. yezoensis . 相似文献
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Sarah C. F. Hawkshaw Michael P. Gillingham J. Mark Shrimpton 《Ecology of Freshwater Fish》2014,23(3):383-394
Flooding river valleys following construction of dams restrict fluvial environments to reaches that were formerly headwaters. Whether remaining habitat is suitable for all life stages of fluvial species is poorly understood. A fluvial species, Arctic grayling Thymallus arcticus, showed a dramatic decline following flooding of the Upper Peace River and the formation of the Williston Reservoir. We related landscape and field site‐specific features with occurrence of juvenile Arctic grayling using an information theoretic approach. For the landscape model, an association was identified between stream order and Arctic grayling occurrence although stream order alone was a poor predictor. A positive association between juvenile Arctic grayling occurrence and distance from the Williston reservoir and stream order, as well as a negative association with water temperature and temperature variance, was deemed important for the field site model. Both modelling approaches indicated size of stream system to be an important influence on occurrence of juvenile grayling in the Williston watershed. River length required for suitable river habitat for salmonids has not previously been identified, but should be factored into future management plans when evaluating the impact of proposed hydroelectric dams and subsequent flooding of river systems. 相似文献
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We address the importance of the isoelectric point (IEP) of proteins and membrane components such as phospholipids for our
understanding and interpretation of isoforms and opposite charge interactions in the formation of complexes. Five examples
drawn from the literature are newly approached from the IEP point of view to clarify general principles. 相似文献
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An experiment designed to measure the volume variation of a bag-net within a set-net was conducted in Jaran Bay, Kosung, Korea. Three radio-acoustic-linked positioning (RAP) buoys, a time controller with a personal computer and seven pingers were used to measure the volumes of the bags. During the April neap tide, the minimum and maximum volumes of the bag-net were 4173 m3 (at 17.00 h) and 4757 m3 (12.00 h), respectively. The average current directions and speeds were 99.9°, 12.9 cm/s and 104.0°, 2.4 cm/s, respectively. During the spring tide, the minimum and maximum volumes of the bag-net were 2016 m3 (18.30 h) and 4454 m3 (15.00 h), respectively. The average current directions and speeds were 315.6°, 16.1 cm/s and 289.0°, 5.7 cm/s, respectively. The minimum (2016 m3) and maximum (5568 m3) volumes of the bag-net were observed during the period when the spring tide changed to the neap tide. 相似文献
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Abstract This study aimed to develop and test an electrode array for a resistivity fish counter that could be easily installed in a small river without a weir. An electrode array consisting of three steel cables laid in parallel across the stream channel and connected to a microprocessor-based counter was tested in an Atlantic salmon, Salmo salar L., spawning tributary. The accuracy of the counter was assessed by observing fish movements with closed-circuit television. Most salmon moving upstream were registered correctly (90% overall). Detection of downstream movement was less reliable (60% overall), as a consequence of downstream swimming behaviour. The accuracy of the downstream count was improved by tensioning the cable electrodes, but remained lower than that of the upstream count. Since salmon swam repeatedly up- and downstream, this discrepancy resulted in an overestimate of the net upstream count. The accuracy of the downstream count needs to be improved before a bed-mounted electrode array could be used for routine salmon counting. 相似文献