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阿根廷专属经济区内鱿钓渔场时空分布年间差异比较 总被引：3，自引：1，他引：2
阿根廷滑柔鱼(Illex argentinus)是西南大西洋重要的经济性头足类,其中分布在阿根廷专属经济区的渔场是极为重要的作业海区,掌握其渔场时空分布有助于合理利用该资源。根据2008～2011年中国鱿钓船在阿根廷专属经济区内的生产统计资料,利用空间距离分析和聚类分析,对渔场时空分布及其年间差异进行了研究。结果表明,阿根廷专属经济区内2008年的产量明显高于其它三年,2008年渔场主要分布于46°S以南,与其它三年也有所差异。产量重心在各年的2月份差异最小,3月份显示出较大的差异。计算欧式距离表明,2008年和2010年产量重心空间距离最小,2010年和2011年空间距离最大。聚类分析表明,2008年与2010年归为一类,2009年和2011年为一类。对不同月份进行聚类分析发现,不同年份2月均在一类中,空间差异较小,其它月份并没有呈现出明显的规律性变化,同一年相邻月份渔场变化不明显。研究认为,阿根廷滑柔鱼年间渔场分布变化很大,今后应该结合各项生物学指标和海洋环境因子进行全面的分析。 相似文献
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进行了黄鳝喜食的天然动物性饵料蚯蚓、鲢肌肉和配合饲料对黄鳝消化酶活性影响的比较研究。结果表明：(1)黄鳝各消化组织中蛋白酶活性均以摄食蚯蚓组增加幅度最大，其次为摄食鲢肌肉组，而以摄食配合饲料的蛋白酶活性增加最小；(2)胰蛋白酶的活性变化则以摄食鲢肌肉组的增加幅度最大，以摄食蚯蚓组次之，摄取配合饲料组的增加幅度最小；(3)淀粉酶的活性以摄取配合饲料的黄鳝的增加幅度最大，其次为摄食鲢肌肉组，增加幅度最小的为摄取蚯蚓组个体；(4)脂肪酶的活性变化以摄取鲢肌肉的增加幅度最大，其次为摄食蚯蚓的，摄食配合饲料组增加幅度最小。这表明不同饲料对黄鳝消化器官消化酶的活性影响不同，这可能与不同饲料的营养组成、性质有关，食物中的不同营养物质会刺激黄鳝消化器官分泌相应的消化酶，以便更好地消化所摄取的食物。 相似文献
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Over 130 cases of equine periodic ophthalmia (p.o.), which were treated as in-patients at the Equine Clinic of the Free University of Berlin in the last 35 years, were examined statistically in relation to the age and gender of the animals involved as well as to the development of the illness and the season in which it arose. As regards aetiology, the extraction of 71 affected Trotters was investigated. Antibodies to toxoplasmosis, leptospirosis and intestinal parasites were found only in some of the patients. Younger animals, aged between one and four years, and male animals (63.6%) were predominantly affected. The results of the examinations of faeces showed no correlation between cases of p.o. and a vermination of the horses. The examinations for antibodies to toxoplasmosis gave no indication of a participation of the toxoplasmas in the aetiology of recurrent uveitis. In contrast, the results of the examinations for antibodies to leptospirosis, of which 58.8% were positive, showed a seven to ten times higher infection than in healthy horses in Berlin. Breed analysis showed that in certain breeds of Trotters and warm-blooded horses, p.o. illnesses were frequent, supporting the hypothesis that the occurrence of p.o. is due to a hereditary, allergic reaction, triggered by various factors, in particular an infection without clinical signs. 相似文献
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Influence of Colored Light on Growth rate of Juveniles of Fish 总被引：2，自引：0，他引：2
The main aim of our experiments was to study the influence of colored light on juveniles of Carassius carassius, Perccottus glenii and Poecilia reticulata. The species of fish used for studies differ in their biotopes and feeding behavior. The results of experiments demonstrated that different species of fish can have different response to light quality. Thus crucian carp developed better by green light, rotan-by blue and green, guppy - by blue light. By red light the growth rate in all species decreased. The response in different species of fish to the light environment appears to be governed by changes in energy metabolism and hormone disproportionation. 相似文献
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一国的知识产权保护状况,在当今是一个热门话题.然而,海洋领域的科学技术在开发、利用等过程中的知识产权保护状况,却甚少有学者研究.事实上,我国海洋生物技术的专利申请和保护状况不甚理想,在该领域的研究也存在一定的缺失.因此,加强对海洋生物技术专利保护现状及存在问题的研究,吸取他国有益经验并采取一定的措施,为海洋技术创新及维... 相似文献
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The variation of virulence of Renibacterium salmoninarum , the causative agent of bacterial kidney disease (BKD) in salmonid fish, was studied by infecting rainbow trout, Oncorhynchus mykiss (Walbaum), with two isolates (strains 325 and 932) from diseased Atlantic salmon, Salmo salar L., and one isolate (strain 4366) from an apparently healthy Atlantic salmon. Coho salmon, Oncorhynchus kisutch (Walbaum), were injected with the strain 932 to estimate difference in fish species resistance. Fish were removed by random sampling for other study purposes, a study design possible with analysis of lifetime distributions incorporating both sampling-, death- and survival-times. At the end of the experiment, the rainbow trout infected with strains 325, 932 and 4366 had a survival probability of 33%, 51% and 72%, respectively. The coho salmon infected with strain 932 had a 26% survival probability. The strain differences were significant according to the log-rank test, and the risk ratio between the strains ranged from 1·8 to 5·4. The strain from the apparently healthy fish was least virulent. The survival of the fish species was different over time. Rainbow trout were more likely to die early in the time course, but high numbers of coho died later, resulting in an overall risk of mortality of 1·4 in favour of rainbow trout. Differences in virulence may reflect changed selective pressure on R. salmoninarum when introduced from feral stocks into the environment of fish farms. 相似文献
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多囊桁拖网选择性研究中对照网囊网目尺寸的选择 总被引：2，自引：1，他引：1
对比作业法是拖网渔具选择性研究中重要的试验方法之一,而对比试验中对照网囊网目的选择至关重要。研究利用多囊桁拖网不同网目尺寸(20、30、35和40mm)网囊捕获的哈氏仿对虾、小黄鱼和棘头梅童鱼渔获体长分布数据,应用几何相似原理,分析过滤性渔具的选择性,并按不同假设条件下(假设1:符合几何相似原理对渔获具有一定的选择性;假设2:对渔获种类没有选择性),探讨如何合理选择对照网囊网目尺寸。结果表明,对照网网囊网目尺寸为20mm,在上述2种假设下,对选择性模型的拟合、简化及对其它网囊的选择性参数没有显著的影响;在考虑了桁拖网渔具各网囊具有相同相对作业强度,以及桁拖网渔具与普通拖网渔具选择性分析方法上的差异等因素后,认为在此项研究中,将小于20mm网目尺寸的网囊视为没有选择性的对照网囊是可行的。 相似文献
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重金属离子对鱼类血液指标影响的研究 总被引：1，自引：0，他引：1
此次试验的目的是研究鲤鱼经短时间高浓度的重金属溶液的暴露,几项血液学指标的变化情况。鲤鱼分别在铅、铜、镉、锌溶液中暴露3h后,随即转置于清洁水中,并立即随机抽取血液样本,以后隔天抽样,到第96h抽样后完成。结果发现:在红细胞系中,红细胞比容短暂升高,红细胞计数正常,红细胞体积发生临时膨胀,原红细胞比率增加。在白细胞系中,由于淋巴细胞数量的下降导致白细胞计数减少,嗜中性白细胞比率增加。结果表明:即使是在高浓度的重金属离子溶液中短时间的暴露,也会诱发鱼体的应激反应,机体加大能量的消耗来满足红细胞系的适应性变化,白细胞系内则出现了明显的免疫抑制反应,从而导致它们对疾病抵抗力的降低。 相似文献
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Evaluation of transportation methods of juveniles of the Australasian sea cucumber,Australostichopus mollis 
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下载免费PDF全文 The transport of juvenile sea cucumbers to grow‐out sites is problematic as they are prone to damage and mortality. The response of juvenile Australostichopus mollis to simulated transport conditions with and without seawater for different periods of time (2, 4, 8, 12 and 24 h) at different temperatures was evaluated in this study. Sea cucumbers were placed in plastic bags with seawater or wrapped in a seawater‐soaked cloth. Monitoring of evisceration, skin lesions, feeding activity and survival was used to evaluate the success of transportation. The juveniles of this species can withstand being without seawater for up to 8 h with no consequences to their survival and feeding activity. Complete immersion of the juveniles in seawater was found to be the only option for transportation over longer periods, but preventive measures should be taken to avoid detrimental levels of temperature, oxygen and pH. Overall, the existing constraints to moving juvenile sea cucumbers to grow‐out sites can be overcome through preventing desiccation during short‐term transport without seawater, and by the control of temperature for long‐term transportation with seawater. The results suggest that in juvenile sea cucumbers, feeding activity and the presence of skin lesions are more sensitive indicators of the success of transport than evisceration and survival. 相似文献
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实验采用生态毒理学方法,以NH4Cl为实验药物,设置0、50、150和250mg/L实验浓度。通过对野生和养殖群体的四鼻须鲤鱼氨氮对肝脏谷胱甘肽巯基转移酶（GST）活力的影响,比较两个群体抗氨氮能力。结果表明：在相同的氨氮浓度和胁迫时间下,四鼻须鲤鱼养殖群体GST酶活力的变化趋势与野生群体大致相同。除250mg/L浓度组在胁迫5d和10d时,野生群体酶活性略低于养殖群体外,在其余时间点的野生群体酶活性均高于养殖群体,而且,在高浓度氨氮胁迫下,野生群体肝脏的GST酶活性达到峰值的时间比养殖群体更短,显示出较强的抗氨氮能力。 相似文献
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ABSTRACT: Cage aquaculture is increasing in importance in fisheries. However, in past studies the relationship between drag force and volume coefficient of the cage bag, and four key factors affecting its efficiency, i.e. flow velocity, ratio of depth to width of the cage, twine diameter to bar length of netting ( d/l ), and weight of the cage has been limited to partial regression and qualitative discussion. This paper establishes two non-linear regressions of the drag force and volume coefficient of a cage bag with seven flow velocities, five ratios of depth to width of the cage, four d/l , and five weights of the cage. The experimental data are processed using the forward selection method in the stepwise regression selection procedure in order to prioritize each factor, and then establish non-linear regressions of the drag force and volume coefficient using multiregression analysis. The results show that factors affecting the drag force are, in order of importance, flow velocity, ratio of depth to width of the cage, d/l and weight. With respect to the volume coefficient, factors in order of importance are flow velocity, weight, ratio of depth to width of the cage, and d/L. The two regressions can predict drag force and volume coefficient more comprehensively than those in previous studies. Finally, the regressions are applied to the full-scale structure of the cage by Tauti's modeling rules. 相似文献
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为了阐明长湖5种土著鲌类摄食器官形态特征间的差异,于2014年采集红鳍原鲌(Chanodichthys erythropterus)、翘嘴鲌(Culter alburnus)、达氏鲌(C.dabryi)、蒙古鲌(C.mongolicus)、拟尖头鲌(Erythroculter oxycephaloides)等5种鲌类共277尾,采用非参数检验、方差分析和判别分析等对5种鲌类的11个摄食器官形态指标和食物组成进行比较分析。结果显示,长湖5种鲌类摄食器官形态特征存在差异,差异主要表现在上、下颌伸展度、口宽3个性状上;典型判别分析显示5种鲌种间离散程度较高;聚类分析表明翘嘴鲌和达氏鲌摄食器官形态相似度最高,蒙古鲌和红鳍原鲌相似度最低。长湖翘嘴鲌、达氏鲌、蒙古鲌的食物主要以、鲫鱼、麦穗鱼和虾为主;水草是红鳍原鲌食物的重要组成部分,昆虫在拟尖头鲌食物中占有一定比例。表明5种鲌在食物组成上有一定的相似性,但在主要饵料的种类和比例上存在差别。由此可以看出,长湖5种鲌摄食器官形态与食性之间表现出一定程度上的适应性。 相似文献
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Evangelia Gouva Cosmas Nathanailides Ioannis Skoufos Ioannis Paschos Fotini Athanassopoulou Ioannis S. Pappas 《Aquaculture Research》2020,51(8):3255-3267
This study aimed to investigate the effects of heavy metals, such as copper, zinc, iron, cobalt, chromium, aluminium, manganese and molybdenum, on zebrafish egg hatching rate and the subsequent survival rate of the larvae. Each metal was used in the various concentrations of0.05 mg/L, 50 mg/L and 500 mg/L to detect the threshold limit of tolerance. The study's results showed significant differences in the hatching and survival rate of larvae between the control group and most of the experimental groups when adding heavy metals in various concentrations. The highest concentration (500 mg/L) of the induced heavy metals tested in this study resulted in total egg or larval mortality within 96 hr and significantly lower egg or larval life expectancy. Among the tested metals, zinc and molybdenum had the most significant impact on hatching time, in contrast to iron that did not differentiate the results from the control group. Copper, cobalt, chromium, aluminium and manganese did affect zebrafish eggs depending on their exposure concentrations, which differentiated the results from the control group. Also, the study's findings demonstrate a significant dependence of the hatched egg heart rate on the metal concentration, and in particular, higher concentrations of metals correspond to higher heart rate. Zinc, Molybdenum and copper was proved to be the most toxic heavy metals causing increased hazard rate to mortality up to 96 hr and shorter life expectancy. Finally, skeletal deformities that occasionally observed did not significantly affect the total life expectancy of the hatched eggs. 相似文献
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中华鳖群体DNA指纹分析中的RAPD技术优化 总被引：1，自引：0，他引：1
以中华鳖(Pelodiscus Sinensis)4种不同区域代表性群体黄河鳖、太湖鳖、台湾鳖和日本鳖为研究材料,采用不同反应条件(如退火温度和循环次数等)对RAPD扩增技术进行了优化研究,结果表明,在条件优化后(退火温度为38℃,循环次数为40次)有20个RAPD引物在4个群体中均有扩增条带,其中随机引物S105能将黄河鳖群体和太湖鳖、台湾鳖、日本鳖群体区分开;随机引物S327能将日本鳖群体鉴别出来;而随机引物S474可将台湾鳖群体与其他群体分开.由此表明,退火温度和循环次数的优化有利于中华鳖RAPD鉴定技术的建立.本研究旨在为中华鳖的种质鉴定与保护提供技术支撑. 相似文献
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《Fisheries Research》1988,6(2):181-189
Bottom-set gillnets are affected by tidal flow. Water pressure pushes the netting out of the vertical plane into curves and the headline height is lowered. The use of self-recording manometers to measure gillnet height in the sea is described. Records of height variation over tidal cycles are given and related to water current measurements. Large changes in headline height were observed at peak tidal flows, particularly in nets set perpendicular to the flow. 相似文献
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Abstract. Papillomatosis of the European eel Anguilla anguilla L. occurs predominantly in waters of low to medium salinity (3–20%). Tumour-bearing eels were kept under laboratory conditions for several weeks in salt concentrations of 8, 15 and 30%. As opposed to those kept in freshwater, the experimental animals showed significant decreases in tumour growth rate. At the same time the tumour tissue underwent a marked redifferentiation, i.e. the originally poorly differentiated neoplastic tissue developed numerous mucous and club cells. The characteristic intercellular spaces of tumorous tissue disappeared with the formation of regular membrane interdigitations between adjacent cells. The nucleus to cytoplasm ratios of the neoplastic cells decreased to one-third of those of the untreated tumour. These changes resulted in a reversion of the neoplastic tissue to a structural condition essentially similar to that of normal epidermis. After a period of 2 to 3 months an adaptation to the altered salinity of the external medium was evident in that the tumorous tissue began to return to its original state. 相似文献