卵形鲳鯵人工育苗技术的研究

在卵形鲳鯵人工育苗技术的研究中，进行了不同饵料对仔鱼生长及成活率影响的试验，培育出体长3～5cm鱼苗23万尾．平均成活率为57．5％。结果表明用螺旋藻强化培育轮虫和采用二次培育方法进行卵形鲳鯵人工育苗．可提高鱼苗的成活率。     

花尾胡椒鲷室内与室外人工育苗的比较研究

将花尾胡椒鲷(Plectorbinchus cinctus)的受精卵在室内育苗池和室外大池不同环境下进行人工育苗比较试验,在26℃～28．8℃的水温条件下,室内培育盐度保持26左右,室外大池的盐度变动范围为26．2～22．9,经过36d的培育,结果显示：①在室内育苗池培育的鱼苗成活率最高为13．9％,最低为6．4％,平均为11．0％;室外培育的成活率仅为6％,室内培育相对室外培育的成活率增加45．5％。②室内培育的鱼苗平均体长为34．5mm,室外培育为52．1mm,室外培育相对室内培育鱼苗体长增加33．6％。③活力试验。室内培育的鱼苗成活率最高为94．8％,最低82．4％,平均为90．9％,而室外培育的鱼苗成活率则达到99．6％,室外培育相对室内培育鱼苗活力试验的成活率增加8．0％。因此,室内培育鱼苗的成活率相对较高,但生长缓慢,活力较差;室外培育鱼苗成活率相对较低,但生长快,活力强。     

营养强化的轮虫在鲻鱼育苗中的效用

经连续2a采用小球藻轮虫、酵母轮虫和乌贼肝油＋小球藻进行营养强化的轮虫培育鲻鱼苗，直观比较鱼苗的存活率和生长发育情况。结果表明：以乌贼肝油营养强化轮虫为饵的鱼苗，经35d的培育存活率最高，为25％－61％；以小球藻轮虫为饵的鱼苗次之，存活率为13％－24％；而以酵母轮虫为饵鱼苗的存活率是最低的，仅培育10－15d，仔鱼就全部死亡；以乌贼肝油营养强化轮虫为饵的鱼苗生长速度最快，个体大小整齐、肥满，变态时间比小球藻轮虫组提早1－2d，最长达3－4d。     

南麂海区美国红鱼网箱养殖试验

1996年 1 0月底从青岛引进平均体长为 2 .1 cm、体重为 0 .5 g的美国红鱼苗 75 0 0尾在南麂海区进行网箱养殖试验 ,养至 1 997年 1 2月 2 5日止 ,其平均体长为 3 2 .8cm,尾均重达6 92 .8g,鱼苗期成活率为 5 5 .7% ,养成期成活率达 98.4% ,饵料系数为 7.2 2～ 9.5 9。此外 ,还对该鱼的放养时间、苗种培育、鱼病防治、人工增殖以及网箱抗风浪措施等问题进行了初步探讨     

提高日本对虾人工育苗成活率的研究

通过日本对虾Penaeusjaponicus人工育苗中饵料配给、水质处理和控制,以及幼体病害防治的单因子和多因子正交试验及大面积生产验证,对提高日本对虾人工育苗成活率的几项关键措施进行了探讨。结果表明：（1）在Z期,添加螺旋藻Spiralsp.粉10g·（1．0×106尾·d）-1、光合细菌2ml·（m3·d）-1和Z3期添加卤虫Artemia无节幼体1-2个·ml-1,使Z1－M1期幼体的成活率提高10％-15％;（2）用36％甲醛0．065－0．13mmol·dm-3和光合细菌2ml·（m3·d）－1处理并改良育苗水质,以及在N期1次性加水75％,至M3期加满,P1-5期换水6％－10％,P6-10期换水15％－20％,用此方法控制育苗水质,作用显著;（3）用间投联用0．5g·（m3·d）－1抗菌素的方法预防幼体细菌病效果良好;（4）在10个总水体为543m3的育苗池中,共育出P8-10期的虾苗3．026×107尾,单位平均出苗量为5．5×104尾·m－3,N-P8-10期的成活率最高达65％,平均为54．6％。     

利用单胞藻培养池进行真鲷育苗技术

１９９３年，于文登市小观海珍品育苗养殖场，在海湾扇贝和对虾育苗结束后，利用其配套的单胞藻培养地进行真鲷育苗，利用对虾育苗池和卤虫孵化池培养轮虫。在不增加任何设备的前提下，育成全长３．０１～６．５０ｃｍ，平均全长３．４４ｃｍ的真鲷商品鱼种１６１１１６尾，从仔鱼培育到商品苗种的成活率达到２４．７２％，平均单位水体出苗量达到２６８５尾，１９９３年７月１９日通过了文登市科委组织的验收。正材料和方法１．１育苗设施亲鱼产卵池（１个）和鱼苗培育池（６个）皆用单胞藻培养池（规格为３．８ｍ×３．７ｍ×０．８ｍ，水…     

不同饵料对斜带髭鲷稚鱼生长和存活的影响

采用5种饵产分别投喂斜带髭鲷（Hapalogenys nitens Richardson）33日龄稚鱼，27d后测定其全长和成活率。结果表明，投喂卤虫无节幼体，斜带髭鲷稚鱼生长最快，成活率最高。全长增长达2．22－2．82倍，平均成活率达21．8％－22．5％；投喂枝角类，斜带髭鲷稚鱼生长也较快，全长增长1．99－2．07倍，平均成活率18．2％。投喂轮虫和人 工配合饲料，斜带髭鲷稚鱼的生长和成活率均很低，全长增长分别仅为1．63－1．72倍和1．47－1．56倍，平均成活率分别仅为1．3％－2．0％。投喂卤虫无节幼体和枝角类的试验组，分别有41．2％－100％个体发育至幼鱼阶段，而投喂轮虫和配合饲料的试验组，全部个体仍停留在稚鱼阶段。可以认为，卤虫无节幼体和枝角类是斜带髭鲷稚鱼较适宜的饵料。     

红鳍笛鲷池塘人工育苗技术初步研究

本文报道了在海水池搪进行红鳍笛鲷人工育苗的实验结果．实验水温为26～32℃，盐度为25～31，经过33～35d的培育，3口池塘鱼的苗平均全长分别为35．3、32．3、28．5mm，成活率分别为16．7％、18．1％、7．8％．本文还对仔鱼的放养密度、生长状况、饵料系列以及池塘中主要生物饵料密度变化作了较为详细的阐述。     

5种淡水浮游藻对萼花臂尾轮虫饵料效果的比较研究──藻的最适投喂密度及轮虫相应的种群增长

于1993年9月在山东省胶南市鱼苗繁殖地池塘采得萼花臂尾轮虫,采用种群累积培养法,对其摄食5种淡水浮游藻的最适密度及其相应的种群增长进行研究。结果表明,该轮虫摄食这5种藻的最适密度（×106cell／ml）分别是：蛋白核小球藻,45;斜生栅藻,25;小球衣藻,5;卵形隐藻,0．2;中型裸藻,0．1。导出了藻的细胞大小（x）和最适投喂密度（y）之间的回归方程为：y＝－15．5＋216／x（r＝0．9826,P＜0．01）。在5种藻的最适密度下比较了投喂轮虫的饵料效果,结果是,5种藻中以蛋白核小球藻和斜生栅藻为最优,其它依次为卵形隐藻、小球衣藻和中型裸藻。据此,认为蛋白核小球藻和斜生栅藻是该轮虫批量培养乃至工厂化培养的首选饵料。     

菲律宾蛤仔苗种土池中间培育及越冬生产实验

利用2．6hm^2和3．13hm^2 2个养虾池,经过池底清淤、底质改良、敌害清除、培养用水处理、繁殖基础饵料生物等工作后,分别移入在室内培育的菲律宾蛤仔（Ruditapes philippinarum（Adams et Reeve））壳顶后期幼虫和双水管稚贝各80亿粒和9．7亿粒,经土池中间培育、越冬后,生产出2000-3000粒／500g幼贝7．9亿粒。自移入幼虫和稚贝到幼苗出池,成活率分别为4．5％和44．3％,达到了较高水平的中间培育、越冬成活率。     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

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.     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

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.     

A Review of Some Environmental Issues Affecting Marine Mining

This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested.     

Increased Particle Fluxes at the INDEX Site Attributable to Simulated Benthic Disturbance

Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement.     

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.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

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。     

Determination of In Situ Sediment Shear Strength from Advanced Piston Corer Pullout Forces

The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments.     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

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.     

Flow Cytometric Analysis of Coastal Lagoon Bacterioplankton and Picophytoplankton: Fixation and Storage Effects

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.