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用LHRH-A2埋植法诱导池养鲻鱼卵母细胞发育成熟的试验 总被引：2，自引：0，他引：2
将含LHRH－A2的药物颗粒埋植入池养人工繁殖鲻鱼Mugil cephalus Linnaeus雌鱼体内，以诱导其性腺发育成熟，试验为期81d。发现用LHRH－A2埋植的试验组鱼的卵母细胞直径超过500μm以上，达到成熟的个体比率为30％，而空白对照组鱼达到成熟的个体比率为0％。试验结果表明，采用激素埋植的方法，可促进鲻鱼卵母细胞的发育。 相似文献
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海产鱼类单殖吸虫——头锚虫及其一新种的描述 总被引：1，自引：0，他引：1
本文报道1964年8月从福建惠安及1978年4月从厦门集美采获的鲻鱼Mugil cephalus鳃上寄生的二种头锚虫Ancyrocephalus,其中一种为新种。现记述如下:(文中数据以毫米为单位)。 相似文献
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目前世界上已养殖或正在试验的鲻鱼种类近二十余种。共中以鲻鱼Mugil cePhalus分布最广。它食物链低、适盐性广及生长快,已成为很多国家咸水和半咸水水域的主要养殖或试验养殖对象,共生产潜力业已引起各国的重视。 近年来鲻鱼人工繁殖研究尤着重于人工诱 相似文献
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本文研究环境光强与黄鳍鲷(Sparus latus)和普通鲻鱼(Mugil cephalus)两种幼鱼视网膜运动反应的关系,结果表明:当光强分别低于10~(-3)1x和10~(-2)1x时,对黄鳍鲷和普通鲻鱼幼鱼视网膜运动反应无明显影响;当光强分别高于10~(-3)1x和10~(-2)1x时,光强越高,两种幼鱼视网膜从暗适应状态过渡到明适应状态的时程越短。黄鳍鲷幼鱼从暗视向明视过渡的照度界限为10~(-3)—10~(-1)1x;普通鲻鱼幼鱼的相应过渡照度界限为10~(-2)—10~01x。 相似文献
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本研究使用稳定同位素方法,分析及比较了吕泗渔场两种重要石首鱼科鱼类(小黄鱼Larimichthys polyactis、棘头梅童鱼Collichthys lucidus)的营养生态学特征。结果表明,不同体长组间小黄鱼和棘头梅童鱼的稳定碳同位素差异不显著(p0.05),而稳定氮同位素差异显著(p 0.05)。小黄鱼的营养级要显著高于棘头梅童鱼(p 0.05)。聚类分析的结果可将小黄鱼的体长组分成两大组,包括 140～190、 130～140、 120～130、 80～90 mm一组和剩余的体长组;棘头梅童鱼的体长组可分为140～190、130～140 mm一组和剩余体长组。Iso Source模型的结果显示,浮游植物对小黄鱼、棘头梅童鱼的碳源贡献比例为43.38%和36.38%;底质有机物(Sedimental Organic Matter,SOM)对小黄鱼、棘头梅童鱼的碳源贡献比例为40.66%和43.70%。因此判定小黄鱼和棘头梅童鱼的潜在碳源主要是浮游植物和SOM。本研究还发现小黄鱼食性转变的体长临界点为80 mm,而棘头梅童鱼为110 mm,反映了棘头梅童鱼在生活史中转变食性行为的发生时间可能比小黄鱼晚。 相似文献
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运用多变量形态度量学分析方法,对我国沿海的四个鲻鱼群体110个个体的形态变异进行了分析。聚类分析和主成分分析结果表明,位于我国南部沿海的广东湛江群体(ZJ)与福建厦门群体(XM)形态最为接近,位于北部沿海的河北塘沽群体(HB)与山东青岛群体(QD)的形态最为接近;而南、北部群体间的趋异程度较大,有一定程度的形态分化。主成分分析前3个主成分对不同群体间总变异方差的贡献率分别为:50.00%、12.16%、11.10%,累积贡献率为73.25%。主成分分析结果表明,四个鲻鱼群体在形态上的差别很大程度上是由体型的高低、长短引起的,且主要集中在胸部和尾部。判别分析中采用9个不同的变量,分别构建了四个鲻鱼群体的判别公式,判别正确率达到99.1%。 相似文献
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采集丹东近海的黑鳃梅童鱼29个个体和海洲湾近海的棘头梅童鱼30个个体,开展2种梅童鱼形态特征比较研究。对2种梅童鱼的顶枕部小棘、臀鳍第一鳍棘、鳔侧枝、鳃腔和耳石等部位进行拍照及形态描述,并进行了2种梅童鱼传统形态学的8个分节特征和14个量度特征的判别分析、主成分分析和单因子方差分析。结果显示:2种梅童鱼的顶枕部小棘、鳔侧枝、鳃腔颜色和耳石形态存在明显差异;除鳔侧枝数有明显差异外,其它可数性状均无显著差异。采用贡献率大的8个参数建立2种梅童鱼的判别公式,判别准确率达100%;黑鳃梅童鱼和棘头梅童鱼在外部形态可量数据上虽存在个别交叉,但仍能形成各自相对集中的组;在P=0.01显著性水平下进行单因子方差分析,结果2种梅童鱼在7个变量上存在显著性差异。 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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Rahul Sharma 《Marine Georesources & Geotechnology》2000,18(3):237-250
Observations on seafloor features from subbottom profiling and seabed photography data show that the undisturbed and natural conditions before the benthic disturbance undergo a substantial change after operation of the disturber. The effects can be seen in the form of deep trenches and grooves, formed by the action of the sleds and the pumping of the sediment along its path, as well as sediment piles on either side of the track. Biological traces such as fecal coils, casts, tubes, burrows, and trails get obliterated in the areas of disturbance and resedimentation. The smooth, uniform nature of the seafloor observed in predisturbance phase shows microtopographic changes in and around the disturbed area as a result of sediment excavation and resettlement. Vertical mixing as well as lateral transport of sediment alter the geological, biological, physical, and chemical conditions on the seafloor, which need to be monitored over time to assess the process and the time taken for restoration of environmental conditions. 相似文献
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Vance P. Vicente 《Marine Ecology》1989,10(2):179-191
Abstract. Long-term changes in the distributional patterns of commercial sponges ( Spongia spp. and Hippospongia spp.) within the West Indian Region indicates that: 1) commercial sponges had a widespread distribution throughout the whole West Indian Region and were ubiquitous in very shallow water until about the first half of the present century; 2) they were fished commercially not only in the traditional northern Caribbean sites (Florida, Gulf of Mexico, Bahamas) but also in the Greater ( e. g. , Hispaniola, Jamaica) and Lesser Antilles; and 3) they became extinct throughout most of the Lesser Antilles ( e. g. , Puerto Rico, Vieques, St. Thomas) sometime during the first half of this century. Mortalities of spongiids within the Antilles were found to differ from other marine mortalities in that: 1) species disappeared from a large region; 2) species vanished from different habitats and depths; and 3) natural populations never recovered. Species richness patterns suggest that commercial sponge genera ( Spongia and Hippospongia ) evolved under slightly cooler elimatic conditions than those found at present, and that these extinctions occurred as a direct or indirect effect of positive thermal anomalies in sea surface and atmospheric temperatures between 1900–1950. The concept that species diversity is stable on a regional scale is questioned. 相似文献
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The behaviour of an axially pre-loaded cylindrical member of an offshore structure, hit by a supply ship, has been investigated. The effects of axial pre-loading on the dynamic properties of members, the extent of damage and propagation of dynamic instability in the tubular members have also been investigated. Numerical models have been validated using available experimental data from the literature although these are mostly static with no pre-loading. Axial pre-loading was found to change the dynamic characteristics of some cylindrical members quite dramatically while it had no significant effect on others. The study examined whether there was any change in the behaviour between local and global modes when the loading was dynamic rather than static. The effect of damping on the dynamic instability of axially pre-loaded tubes under lateral dynamic loads was also studied. It was observed that for some geometries the quasi-static response can be used to define the boundary between bounded and unbounded dynamic responses. The main contribution of this study, compared with previous investigations reported in the literature, is that both pre-loading and dynamic effects have been included. 相似文献