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长江口环境条件对日本鳗鲡(Anguilla japonica)鳗苗溯河洄游的影响 总被引：1，自引：0，他引：1
长江口是日本鳗鲡鳗苗的手要产区,利用2007年1-5月在长江口的长兴岛、横沙和杭州湾小洋山4个取样点得到的日本鳗鲡鳗苗渔获量数据,初步研究了鳗苗的补充时间分布以及补充量与潮汐、月相等环境因素之间的关系.发现鳗苗在长江口的补.充时间从1月下旬开始到5月中旬结束,鳗苗日产量峰值出现日期从长江口外向内逐渐推迟,与其洄游路线致.长江口附近潮汐为半月潮,每月有两次涨落潮,鳗苗溯河量与潮汐周期呈现一定的节律性,每月有两次鳗苗峰值.河口区鳗苗溯河具有潮流选择性,长江口内鳗苗溯河量起汛潮多于落汛潮:长江口外鳗苗溯河量和潮汐振幅呈现正相关趋势.日本鳗鲡鳗苗的溯河量与月相变化也有一定的关系;朔月望月的平均单网捕捞量之和占总平均单网捕捞量的93.13%,而上下弦只占6.87%.经过方差检验,朔月鳗苗溯河量多于望月,且二者之间存在极显著差异(P<0.01). 相似文献
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本文根据１９９４年７月至１９９５年４月间４个航次调查资料而得。结果表明，九龙江口ＡＴＰ的含量平均值为２７８．４μｇ／ｍ＾３，变化范围在３２．４￣８５７．６μｇ／ｍ＾３之间。ＡＴＰ与叶绿素ａ和ＰＯＣ之间存在着正相关性。Ｃｈｌ－ａ／ＡＴＰ的高值区出现在盐度为２５￣３０间。ＰＯＣ（Ｂ）／ＰＯＣ的高温区出现在盐度为１５￣２５间。该区域颗粒碳含有最大比例的活体的有机碳约占６０％。 相似文献
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牙鲆（Ｐａｒａｌｉｃｈｔｈｙｓ ｏｌｉｖａｃｅｕｓ）的常温育苗已有过一些报道［１～３］。为了提高牙鲆苗种规格，增强苗种度夏能力，缩短养殖周期，１９９５年我们在荣成市马山渔业公司育苗场进行了牙鲆升温育苗生产。截至７月６日巳育出全长５～１０ｃｍ大规格牙鲆亩种３０００００尾，至自然水温达到最高值的８月下旬，部分鱼种全长已达１５ｃｍ以上，大大增强了苗种度更能力，提高了苗种度夏成活率。１亲鱼培育及产卵１．１亲鱼培育１９９６年第５期于１９９４年１１月份购入海上捕捞的牙鲆亲鱼３３尾，全长范围４０～７５ｃｍ，体… 相似文献
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中草药添加剂应用于甲鱼养殖试验简报 总被引：2，自引：0，他引：2
中草药复方添加剂应用于甲鱼养殖,添加在甲鱼配合饲料中,按每１００ｋｇ甲鱼重添加６０ｇ实验。于１９９６年７月至１９９８年８月,２个甲鱼场的实验结果表明：稚鳖（３￣５０ｇ培育阶段）平均成活率９１．３％,幼鳖（５０￣１５０ｇ养殖阶段）平均成活率９２．６％,成鳖（１５０￣５００ｇ或以上养殖阶段）,平均成活率８８．７％,整个养殖过程成活率平均达到７５．０％。养殖周期缩短至１０￣１４个月,投入与产出比为１：１ 相似文献
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１９９５年分别在邵武欣隆绿色养殖有限公司养殖池和诏安桥东溪雅鳗场对规格１１０ｐ／ｋｇ、７２ｐ／ｋｇ、７２／ｐｋ的欧鳗用我公司开发的欧鳗专用饲料－“海马”牌黑仔７＾＃饲养７１ｄ与６７ｄ的试验。结果表明，投饵率为１．２％－１．８％；成活率为９９％；饵料效率在８２．１％－８４．５％之间。 相似文献
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闽江口浮游桡足类生态研究 总被引：7，自引：3，他引：7
１９９０年５月至１９９１年１月对闽江口进行了调查，共鉴定浮游桡足类３７种，其中近岸类群的种类最多，河口种的数量占优势，并制约了桡足类总量的季节变化。数量密集区主要出现在调查区西部的岛屿及近岸水域，东部近岸水域的种类较西部丰富。多样性的分布趋势为由河口向海洋愈趋稳定。暖温带种虫肢歪水蚤和暖水种右突歪水蚤等分别在闽江口区和九龙江口区的分布，似可指示闽江口区的暖水性生态略弱于九龙江口区。 相似文献
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岩鹭在厦门海岸带的分布及其生态考察 总被引：7，自引：0，他引：7
岩鹭是我国二级保护鸟类,处于稀有的濒危状态。１９９３年３￣５月,１９９３年９月至１９９４年９月和１９９５年５￣１０月的考察结果。证实岩鹭在厦门的居留时间为１０月上旬至６月上旬。厦门的岩鹭分布于东部海岸,该区域人为干扰和污染少,潮间带底质以砂砾,岩石为主,厦门的岩鹭为灰黑色型,单独活动,种群总数量只有３￣５只,本文根据岩鹭的生态需求、行为习怀和种群数量特点,对岩鹭的保护也进行了讨论。 相似文献
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Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
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The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
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《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
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The relationship between the flux of exotic benthic foraminiferal tests (i.e. tests which are supplied from open-sea sources alone) in a tidal inlet and that of bulk sediment was analysed, which can be expressed as two first-order linear equations. According to this relationship, in order to determine net sediment transport directions in the entrance, the test concentration in surficial sediments of the tidal basin can be compared against a ‘ critical level ’. The critical level is determined for the conditions that no net transport of bulk sediment is present within the entrance. If the observed concentration (averaged over the tidal basin) is higher than the simulated critical level, then the net sediment transport is directed to landward. This method is applied to the analysis of net sand transport at Christchurch Harbour, a tidal inlet system located in southern England. In this investigation, concentrations of exotic foraminiferal tests in the surficial sediments of the tidal basin and ebb tidal delta area were obtained from the analysis of sea-bed sediment samples. A series of probable critical levels were calculated based upon the data sets with regard to: (1) sediment discharge from the rivers; (2) magnitude of sediment discharge within the entrance during the ebb; (3) the test concentration outside the harbour; (4) the thickness of the moving layer; and (5) two parameters associated with dispersive processes. The results show that the concentration in the tidal basin sediment is higher than a number of simulated critical concentrations for representative cases. Consequently, the high level of the concentration of exotic benthic foraminiferal tests within the harbour should be explained as a result of landward net transport of sands within the entrance. 相似文献
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Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding. 相似文献
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Hoi-Soo Jung Kap-Sik Jeong Yong-Shik Chu Sung-Hyun Park Ki-Hyune Kim 《Marine Georesources & Geotechnology》2001,19(3):181-195
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors. 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2001,24(1):27-33
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake. 相似文献