共查询到20条相似文献，搜索用时 515 毫秒
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花尾胡椒鲷人工繁殖及育苗技术研究 总被引：1，自引：0，他引：1
海水网箱饲养的3龄花尾胡椒鲷，催产前2个月进行培育，用绒毛膜促性腺激素（HCG）和LRH－A3激素进行催产，混合或单一使用，剂量视亲鱼性腺的成熟度而定，受精卵在盐度为31，PH为80－8．4，水温20－23℃的海水中，经35－36h完成胚 发育，破膜卵孵出成仔鱼。室内水泥池，在盐度为25－26，PH为8．0－8．4，水温24－26℃的海水中，仔鱼经36d培育，态进行幼鱼期；室土肥有苗，在海水盐度为22－31．1，PH为8．0－8．4，水温19－24℃时，仔鱼经30d培育，完成变态进入幼鱼期。 相似文献
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对养殖岱衢洋大黄鱼进行人工催产、自然产卵获得受精卵,在人工培育条件下观察了其胚胎及仔稚幼鱼发育过程。结果表明:1)岱衢洋大黄鱼受精卵呈圆球形,浮性;2)在水温23.0~24.0℃、盐度22.1条件下胚胎发育历时25.5h,主要经历了卵裂期、囊胚期、原肠胚期、神经胚期、器官形成期及孵化期等阶段;3)在水温22.0~24.0℃、盐度22.1~23.4条件下,仔鱼发育经历了前期仔鱼(0~7日龄)和后期仔鱼(8~18日龄);4)19日龄进入稚鱼前期,各鳍齐全;5)29日龄进入稚鱼后期,鳞片出现;6)36日龄以后全身被鳞,进入幼鱼期。仔稚幼鱼生长方程为TL=0.570 3 D+0.750 1(R2=0.965 8),全长和日龄呈极显著线性相关。 相似文献
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为开展黄鳍东方鲀(Fugu xanthopterus)批量全人工育苗、胚胎及仔稚幼鱼发育特征研究, 作者使用地欧酮(DOM)、促黄体释放激素类似物(LRH)及绒毛膜促性腺激素(HCG)对性成熟黄鳍东方鲀进行人工催产。结果表明黄鳍东方鲀亲鱼效应时间为39～60h, 获产率为55.0%～92.5%; 卵受精率为35.5%～84.7%, 3 年产卵7 400 g; 受精卵在海水水温17.0～23.2℃、盐度21～30、pH8.0～8.2 人工条件下孵化, 孵化率为33.6%～91.7%, 孵出仔鱼499 万尾; 2005 年、2006 年经前期培育, 共培育出黄鳍东方鲀后期仔鱼394.5 万尾, 成活率为68.2%～94.3%; 室内水泥池后期培育出平均全长2.6 cm±0.2 cm 幼鱼3100 尾, 成活率为15.5%; 池塘生态培育出平均全长3.7 cm±0.5 cm 幼鱼53.3 万尾, 成活率为11.2%～13.8%。黄鳍东方鲀受精卵为沉性黏性卵, 近椭球形, 乳白色, 卵膜厚且不透明, 卵径0.9～1.0mm,在海水水温18.2～22.2℃条件下, 3 h 分裂为2 细胞; 3 h 20 min 4 细胞; 3 h 45 min 8 细胞; 10 h 10 min 多细胞; 17 h 30 min 囊胚出现; 28 h 原肠期; 57 h 15 min 胚体形成期; 69 h 20 min 心跳出现; 130 h 50 min出膜期; 144 h 孵出仔鱼。初孵仔鱼全长2.2～2.4 mm, 体圆而粗短, 尾部细长、透明; 孵出后第20 天, 胸鳍、臀鳍、背鳍基本形成, 进入稚鱼期; 孵出后第45 天, 上下颌门齿发达, 各鳍发育完整, 小刺基本形成, 进入幼鱼期。 相似文献
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Mian状黄姑鱼的早期发育研究 总被引：13，自引：2，他引：11
本文对Ｍｉａｎ状黄姑鱼的胚胎和仔、稚鱼各发育阶段的形态特征进行了描述。Ｍｉａｎ状黄姑鱼的爱精卵的为圆球形浮性卵,无色透明。在水温２０￣２３℃,盐度２６￣３０的条件下,经２４ｈ３５ｍｉｎ陆续孵出仔鱼。胚胎发育分为２６期。初孵仔鱼至孵化后４日龄为仔鱼前期;孵化后５￣２２日龄为仔鱼后期;孵化后２３￣３２日龄为雅鱼期;孵化后３３日龄进入幼鱼早期。仔、稚鱼培育水温１８￣２８℃,盐度２０￣３０。仔鱼２日龄稍开 相似文献
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作者对鱼(Miichthys miiuy)的早期发育(从受精卵到45日龄幼鱼)形态特征及生态习性进行了描述。鱼的受精卵在水温21.4℃～22.0℃,盐度25.7条件下,经过29 h30 min仔鱼孵出。从受精卵到仔鱼出膜可分为卵裂期、囊胚期、原肠期、胚体形成期等4个主要时期,然后进入胚后发育阶段。孵出后的3日龄仔鱼已能在水体中平游,极少数个体可开口摄食轮虫。4日龄仔鱼全部开口摄食,并对光反应敏感,出现明显的集群现象。22日龄的后期仔鱼各鳍鳍条发育形成,鳞片开始出现,进入到稚鱼期。39日龄后,鱼全身披满细小的鳞片,全部分布于育苗池的底部,开始进入到幼鱼发育阶段。根据仔、稚、幼鱼形态特征和生活习性对鱼的分类进行了探讨。 相似文献
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《海洋科学》2010,(1)
作者对鮸鱼(Miichthys miiuy)的早期发育(从受精卵到45日龄幼鱼)形态特征及生态习性进行了描述。鮸鱼的受精卵在水温21.4℃~22.0℃,盐度25.7条件下,经过29 h30 min仔鱼孵出。从受精卵到仔鱼出膜可分为卵裂期、囊胚期、原肠期、胚体形成期等4个主要时期,然后进入胚后发育阶段。孵出后的3日龄仔鱼已能在水体中平游,极少数个体可开口摄食轮虫。4日龄仔鱼全部开口摄食,并对光反应敏感,出现明显的集群现象。22日龄的后期仔鱼各鳍鳍条发育形成,鳞片开始出现,进入到稚鱼期。39日龄后,鮸鱼全身披满细小的鳞片,全部分布于育苗池的底部,开始进入到幼鱼发育阶段。根据仔、稚、幼鱼形态特征和生活习性对鮸鱼的分类进行了探讨。 相似文献
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Chandralata Raghukumar G. Sheelu P. A. Loka Bharathi Shanta Nair C. Mohandass 《Marine Georesources & Geotechnology》2001,19(1):1-16
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance. 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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海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。 相似文献
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Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification
An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm. 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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Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations. 相似文献
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Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans 总被引：1，自引：0，他引：1
A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level. 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