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2008年5月20日,对海水网箱养殖的豹纹鳃棘鲈(Plectropomus leopardus Lacépède)亲鱼进行人工催产试验,并对获得的受精卵进行胚胎发育观察,描述其发育各期的形态特征及发育速度.豹纹鳃棘鲈的受精卵呈浮性,透明圆球形,卵径为816.5 μm±15.9 μm,具一直径约145.5 μm的大油球,有些受精卵还含有数个(1～6)小油球.在自然海区水温30.0～31.2℃条件下,胚胎发育时间为16 h32 min. 相似文献
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利用解剖和石蜡切片技术对驼背鲈(Cromileptes altivelis)嗅囊及嗅板细胞进行形态学和组织学研究。结果表明,驼背鲈具有2对鼻孔,前后鼻孔紧相邻,前鼻孔小,圆形,具瓣膜;后鼻孔大,为垂直长裂孔。驼背鲈嗅囊椭圆形,其长径与眼径之比为0.16,长径与短径之比为1.29。嗅囊由20～22个初级嗅板构成,嗅板辐射状,呈菊花瓣图案。嗅板游离端边缘为非感觉区,顶部上皮为单层扁平上皮。感觉区嗅上皮含有4种细胞,可大致分为感觉细胞层、支持细胞层和基细胞层,其中感觉细胞层由感受细胞和纤毛非感觉细胞构成,感受细胞在嗅板上不连续分布,嗅板感觉细胞层表面具较发达的纤毛。驼背鲈应属于以视觉为主进行活动的鱼类。 相似文献
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驼背鲈肌肉营养成分的分析与评价 总被引：1，自引：0，他引：1
采用生物化学方法测定和分析了驼背鲈（Cromileptes altivelis）肌肉的营养成分.结果显示,每100 g驼背鲈肌肉的干物质含量：粗蛋白为84.51 g、粗脂肪为5.28 g、VE为5.59 mg、VB2为0.61 mg、钙为69.60 mg、磷为757 mg、钾为1 490 mg、钠为142 mg、铁为1.05 mg、硒为0.21 mg,钙/磷含量比为1/10.88.驼背鲈肌肉的营养成分属于高蛋白低脂肪类型,肌肉的必需氨基酸模式3 001.31 mg/g优于FAO-WHO的理想模式2 190 mg/g,氨基酸的支/芳值为2.41接近正常人体的水平,氨基酸含量（97.49%）、必需氨基酸含量（48.33%）和鲜味氨基酸含量（37.37%）均较高,氨基酸种类齐全,肉味鲜美,不饱和脂肪酸含量（13.61%）较低.结果表明,驼背鲈肌肉具有较高的营养价值,属于一种优质的海产蛋白源. 相似文献
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温度对管角螺Hemifusus tuba (Gmelin)胚胎发育的影响 总被引：1，自引：0，他引：1
在pH8.1～8.3、盐度27.5～29.5的条件下,进行了不同温度对管角螺Hemifusus tuba(Gmelin)胚胎发育影响的试验。结果表明,管角螺的卵子在发育过程中分为正常卵和败育卵;其胚胎发育过程属直接发生型;孵化率达80%以上的海水温度范围为22.1~31.2℃;正常发育的胚胎5~9 d能完全消耗卵囊内的败育卵并变为自身发育的营养物质,12~18 d形成稚螺雏形,29~38 d胚胎完成发育,形成稚螺。 相似文献
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《海洋湖沼通报》2016,(5)
对人工繁育的花鲈(Lateolabrax maculatus)早期发育阶段的形态特征及苗种培育技术进行了观察与研究。结果表明:在水温17±1℃、盐度30、pH8.0、溶解氧7.0mg/L的条件下,花鲈受精卵经过72h完成胚胎发育过程。在胚后发育阶段,根据卵黄囊体积、鳍条发育情况,将花鲈前期发育划分为仔鱼期、稚鱼期、幼鱼期;仔鱼期又可分为前期仔鱼和后期仔鱼。本文对培育过程中死亡率较高的仔鱼期进行了详细观察,发现在水温16~17℃,盐度30的海水中培育,初孵仔鱼至5日龄(day post hatching,dph)仔鱼是前期仔鱼,6~35dph为后期仔鱼。花鲈个体之间发育速度差异较大、仔鱼之间的残食现象是整个培育过程中比较明显的特征,这些特征与冬季水温较低造成的越冬困难一起限制了花鲈苗种的全人工繁育技术的建立。 相似文献
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中国海水鱼类单殖吸虫研究Ⅻ新海盘虫属一新种及海盘虫属一新记录 总被引：1，自引：0，他引：1
报道了寄生于豆娘Abudefdufsp .鳃上的新海盘虫属一新种和寄生于驼背鲈Cromileptesaltivelis鳃上的海盘虫属一新记录。双曲片新海盘虫 ,新种Neohaliotremadi curvilamellatum ,sp .nov .与NeohaliotremabychowskiiZhukov ,1 976相似 ,但支持器的形态结构不同和交接管量度上有差异。驼背鲈海盘虫HaliotremacromileptisYoung ,1 968与原始描述相比 ,除交接管稍长外 ,其它量度与形态基本一致。 相似文献
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本文就汞、锌、铅3种重金属对黑鲷胚胎(包括前期仔鱼)发育的影响进行了研究和讨论,并与铜对黑鲷胚胎发育的影响作了比较。黑鲷卵和前期仔鱼对上述4种重金属的敏感顺序是:汞〉铜〉锌〉铅。初孵仔鱼对汞及胚孔封闭前的发育卵对铜较其它发育阶段更为敏感。初孵仔鱼和脊椎形成前的卵对锌、铅都比较敏感,但大大低于对铜和汞的敏感程度。值得注意的是:在脊椎形成后至孵化前的胚胎发育期间,卵对4种重金属的敏感性都远较胚胎发育的其它阶段低。汞、铅对黑鲷的胚胎发育有较明显的迟滞效应。高浓度的锌和铅引起大量初孵仔鱼的畸变,而在含汞海水中,在胚胎直至前期仔鱼的发育期间无畸变现象发生。 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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This study tests the hypothesis that the in situ void ratio of surficial marine sediments may be predicted from shear wave velocity-depth data with a reliability equal to that of other methods currently available. Shear wave velocity is fundamentally controlled by the number of grain-to-grain contacts per unit volume of material and by the effective stress across those contacts. In this study, three previously established empirical formulae are used to predict void ratio from velocity-depth data. Field data were acquired along a transect off the northern Californian coast across which water depth increased from 35 to 70 m and seafloor sediment type varied from sand to silty-sand, respectively. A towed seafloor sled device was used to collect shear wave refraction data, and a marked, systematic decrease in velocity was observed along the line, ranging from 35-70 m/s for the coarse, near-shore material to 25-40 m/s for the finer, offshore deposits. Void ratios predicted from these velocities were compared with data measured directly from box-core samples. Of the formulae used for prediction, two agree remarkably well with the control data. Both predicted and control values increase from 0.6-0.8 for the sandy material to 1.1-1.5 for the silty-sand. Thus, this study does not disprove the hypothesis set and demonstrates the potential of field shear wave velocity-depth data as a means of delineating spatial variation in void ratio for surficial marine sediments in a remote, nondestructive manner. 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
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Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease (0.84% ～ 1.88%) of organic carbon content from the upper reaches to the estuary.δ13C values of particulate organic carbon was in the range of -24.9×10-3 to -26.6×10-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ13C and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs (soil organic matter) among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream. 相似文献
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Andrzej Chybicki 《Marine Geodesy》2018,41(1):1-23
Current trends of development of satellite derived bathymetry (SDB) models rely on applying calibration techniques including analytical approaches, neuro-fuzzy systems, regression optimization and others. In most of the cases, the SDB models are calibrated and verified for test sites, that provide favorable conditions for the remote derivation of bathymetry such as high water clarity, homogenous bottom type, low amount of sediment in the water and other factors. In this paper, a novel 3-dimensional geographical weighted regression (3GWR) SDB technique is presented, it binds together methods already presented in other studies, the geographically weighted local regression (GWR) model, with depth dependent inverse optimization. The proposed SDB model was calibrated and verified on a relatively difficult test site of the South Baltic near-shore areas with the use of multispectral observations acquired by a recently launched Sentinel-2 satellite observation system. By conducted experiments, it was shown that the proposed SDB model is capable of obtaining satisfactory results of RMSE ranging from 0.88 to 1.23[m] depending on the observation and can derive bathymetry for depths up to 12m. It was also shown, that the proposed approach may be used operationally, for instance, in the continuous assessment of temporal bathymetry changes, for areas important in the context of ensuring local maritime safety. 相似文献
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N. H. Khadge 《Marine Georesources & Geotechnology》2000,18(3):251-258
As a part of the environmental impact assessment studies, geotechnical properties of sediments were determined in the Central Indian Basin. The undrained shear strength and index properties of the siliceous sediments were determined on 20 box cores of uniform dimension collected from various locations in five preselected sites. The maximum core length encountered was 41 cm and most of the sediments were siliceous oozes consisting of radiolarian or diatomaceous tests. The shear strength measurements revealed that surface sediments deposited in recent times (0-10 cm) have a shear strength of 0-1 kPa; this value increases with depth, reaching 10 kPa at 40 cm deep. Older sediments have greater strength because of compaction. Water content varies in the wide range of 312-577% and decreases with depth. The clay minerals such as smectite and illite are dominant and show some control over water content. Wet density, specific gravity, and porosity do not indicate any notable variation with depth, thereby indicating a uniform, slow rate of sedimentation. The average porosity of sediments is 90.2%, specific gravity 2.18, and wet bulk density 1.12 g/cm 3 . Sediments exhibit medium to high plasticity characteristics, with the average plasticity index varying between 105% and 136%. Preliminary studies on postdisturbance samples showed an increase in natural water content and a decrease in undrained shear strength of sediments in the top 10- to 15-cm layer. 相似文献
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An Improved Calibration of Satellite Altimetric Heights Using Tide Gauge Sea Levels with Adjustment for Land Motion 总被引：2，自引：0，他引：2
Gary T. Mitchum 《Marine Geodesy》2000,23(3):145-166
Several major improvements to an existing method for calibrating satellite altimeters using tide gauge data are described. The calibration is in the sense of monitoring and correcting temporal drift in the altimetric time series, which is essential in efforts to use the altimetric data for especially demanding applications. Examples include the determination of the rate of change of global mean sea level and the study of the relatively subtle, but climatically important, decadal variations in basin scale sea levels. The improvements are to the method described by Mitchum (1998a), and the modifications are of two basic types. First, since the method depends on the cancellation of true ocean signals by differencing the altimetric data from the tide gauge sea level time series, improvements are made that produce a more complete removal of the ocean signals that comprise the noise for the altimetric drift estimation problem. Second, a major error source in the tide gauge data, namely land motion, is explicitly addressed and corrections are developed that incorporate space-based geodetic data (continuous GPS and DORIS measurements). The long-term solution, having such geodetic measurements available at all the tide gauges, is not yet a reality, so an interim solution is developed. The improved method is applied to the TOPEX altimetric data. The Side A data (August 1992?February 1999) are found to have a linear drift component of 0.55 + / 0.39 mm/yr, but there is also a significant quadratic component to the drift that is presently unexplained. The TOPEX Side B altimeter is estimated to be biased by 7.0 + / 0.7 mm relative to the Side A altimeter based on an analysis of the first 350 days of Side B data. 相似文献
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Extreme sea levels associated with severe cyclonic storms are common occurrences along the east coast of India. The coastal districts of Orissa have experienced major surges in the past. The recent Paradip super cyclone is one of the most severe cyclones, causing extensive damage to property and loss of lives. Extreme sea levels are major causes for coastal flooding in this region. Damages can be minimized if the extreme sea levels are forecast well in advance. In the present study, we develop a location specific, fine resolution model for the Orissa coast on the lines similar to that of IIT-D storm surge model (Dube et al. 1994). The model runs on a personal computer. The bathymetry for the model is extracted from very fine resolution naval hydrographic charts for the region extending from the south of Orissa to south of West Bengal. A simple drying scheme has also been included in the model in order to avoid the exposure of land near the coast due to strong negative sea surface elevations. An attempt was made in this study to simulate extreme sea levels along the Orissa coast using the data of past severe cyclones. The model results reported in the present study are in good agreement with available observations or estimates. 相似文献
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The continental margin of northern Sinai and Israel, up to Haifa Bay, is the northeastern limb of the submarine Nile Delta Cone. It is made up predominantly of clastics from the Nile and its predecessors. The continental shelf and coastal plain of Israel are built of a series of shore-parallel ridges composed of carbonate-cemented quartz sandstone (locally named kurkar), a lithification product of windblown sands that were piled up into dunes during the Pleistocene. The drop in global sea level and regression during the last glacial period exposed the continental shelf to subaerial erosion and created a widespread regional erosional unconformity which is expressed as a prominent seismic reflector at the top of the kurkar layers. The subsequent Holocene transgression abraded much of the westernmost kurkar ridges, drowned their cores, and covered the previous lowstand deposits with marine sands, which were in turn covered by a sequence of sub-Recent clayey silts. The Mediterranean coasts of Sinai and Israel are part of the Nile littoral cell. Since the building of the Aswan dams the sand supplied to Israel's coastal system is derived mainly from erosion of the Nile Delta and from sands offshore Egypt that are stirred up by storm waves. The sands are transported by longshore and offshore currents along the coasts of northern Sinai and Israel. Their volume gradually declines northward with distance from their Nile source. The longshore transport terminates in Haifa Bay where some sand is trapped, and the test escapes to deeper water by bottom currents and through submarine canyons, thus denying Nile-derived sand supply to the 40-km-long 'Akko-Rosh Haniqra shelf. The sand balance along Israel's coastal zone is a product of natural processes and human intervention. Losses due to the outgoing longshore transport, seaward escape, and landward wind transport exceed the natural gains from the incoming longshore transport and the abrasion of the coastal cliffs. The deficit is aggravated by the construction of (1) seaward-projecting structures that trap sands on the upstream side and (2) offshore detached breakwaters that trap sands between themselves and the coast. The negative sand balance is manifested by the removal of sand from the seabed and the consequent exposure of archaeological remains that were hitherto protected by it. The sediments that escape seaward from the longshore transport system form a 2.5- to 4-km-wide sandy apron adjacent to the shore that extends to where the water is 30 - 40 m deep. The apron's slope (0.5 - 0.8) is steeper than the theoretical equilibrium slope for the median grain-size diameter in this zone (0.1 - 0.3 mm). The beach sands and the apron's surficial sands are well sorted. Their grain size decreases with distance from shore, from 0.2 - 0.3 mm nearshore to 0.11 - 0.16 mm by the drowned ridge. The coarse-grained fraction consists of skeletal debris (commonly 5 - 12% carbonate matter) and wave-milled kurkar grains (locally named zifzif). In deeper water, the basal sands underlying the fine-grained sediment cover consist of 1- to 30-cm layers whose composition ranges from silty sands to various types of sands (fine, medium, coarse, and gravelly) to zifzif. For the most part, they contain large amounts of skeletal debris (20 - 60%) and small fragments of kurkar. Two types of kurkar rock were encountered offshore: a well-sorted, fine- to medium-grained (0.074 - 0.300 mm) lithified dune sand with variable amounts of carbonate cement, ranging from hard rock of low permeability to loose sand; and a porous sandstone made up predominantly of algal grains and skeletal debris (calcarenite). 相似文献