Determining summer residence status and vertical habitat use of sailfish (Istiophorus platypterus) in the Arabian Gulf     

Hoolihan  John P.; Luo  Jiangang 《ICES Journal of Marine Science》2007,64(9):1791-1799

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北方地区秋季日本对虾室内高密度精养的试验   总被引：2，自引：0，他引：2  

林琼武  单保党  刘立东  黄加祺 《台湾海峡》2001,20(4):510-514

为充分利用每年的8月以后直到翌年3月份都处于休闲状态的育苗场设施资源，笔者于1999年8月在河北黄骅进行日本对虾室内高密度精养的试验。在水温23－28℃、盐度28－32下，8月27日放苗，11月24日收成，养殖时间87d，单位水体产量平均为0．818kg/m^3，平均存活率为50．1％，旬生长率平均为0．75cm，成虾体长平均8cm，饵料系数为2．51，投入与产出比为2．5，平均单位水体创利63．83元／m^3，其结果说明本养殖模式不仅是可行的，而且具有利用率和效益高、实用性强的优点。本文还就相关问题进行了讨论。  相似文献   

High Precision Geoid Models HKGEOID-2000 for Hong Kong and SZGEOID-2000 for Shenzhen, China     

Zhicai Luo  Jinsheng Ning  Yongqi Chen  Zhanji Yang 《Marine Geodesy》2005,28(2):191-200

High precision geoid models HKGEOID-2000 for Hong Kong and SZGEOID-2000 for Shenzhen, China, have been developed with a hybrid approach of so-called sequential processing, using high precision GPS/leveling data, land and sea gravity anomalies, and digital terrain models. These two local geoid models have the same 1-km resolution. The estimated accuracy (external accuracy) is better than 1.7 cm for HKGEOID-2000 and 1.4 cm for SZGEOID-2000. Some common areas are covered by HKGEOID-2000 and SZGEOID-2000. So these two geoid models, along with high quality GPS/leveling data collected on the overlapping areas, can be used to detect the systematic bias between HKGEOID-2000 and SZGEOID-2000, as well as the difference between Hong Kong Principal Datum and 1956 yellow sea height datum of China, yielding RMS errors of 1.011 m and 1,003 m, respectively. Moreover, HKGEOID-2000, along with GPS ellipsoidal heights, is employed to determine the errors of the “orthometric heights” from purely trigonometric heighting, yielding an RMS error of 0.102 m. The combination of SZGEOID-2000 and GPS ellipsoidal heights has been used to replace the traditional spirit leveling and mapping, called GPS mapping.  相似文献   

千里岩的气温变化特征及其与西北太平洋副热带高压的关系     

贾瑞丽  郭可彩 《海洋预报》1997,14(4):67-72

本文根据１９６０～１９９４年千里岩和青岛月平均气温资料，分析了千里岩与青岛３５年来气温的年、季变化特征及差别，发现３５年来，千里岩和青岛的年、季平均气温均呈变暖趋势，但千里岩增温幅度较青岛小。从分析中发现，与气温变暖趋势相对应，西北太平洋副热带高压（以下简称副高）面积、强度指数的年、季变化也呈明显的增强、增大趋势。且年平均气温与冬季副高面积指数相关最显著。最后依此关系建立回归方程，并预测了１９９６年千里岩年平均气温的变化趋势。  相似文献   

东海区小黄鱼渔业生物学现状的分析   总被引：15，自引：1，他引：15  

林龙山  程家骅 《中国海洋大学学报(自然科学版)》2004,34(4):565-570

以2001年东海区渔业资源监测调查资料为依据，对小黄鱼的体长、体重、生长、死亡等渔业生物学特征及临界年龄等进行了分析研究。结果表明，目前东海区小黄鱼优势体长组为110～130mm，占41．34％；优势体重组为20～40g，占50．91％；总死亡系数为2．05，自然死亡系数为0．58，捕捞死亡系数为1．47，临界年龄为2．18龄。对照东海区小黄鱼生物学特征的历史状况分析，目前东海区小黄鱼个体小型化、低龄化、性成熟提早现象明显，生物学参数发生较大变化。建议在东海区现行资源状态下，小黄鱼的可捕标准应充分考虑其生物学现状加以科学调整。  相似文献   

中国近海主要鱼类种群变动与生活史型的演变   总被引：2，自引：0，他引：2  

罗秉征  卢继武  兰永伦  黄颂芳  朱德林  孔祥雨 《海洋科学集刊》1993,(34):124-137

物种为了种族的延续和繁衍,在历史的长河中,通过自然选择形成了适应其生存的一系列生态学特征,即生活史的选择型。具有不同生活史型鱼种的数量变动形式也不同,换言之,种群数量的变动方式是各个种生活史的反映,种群动态与其生活史选择型有着密切关系。 随着海洋渔业的发展,以及人类对海洋渔业资源开发与利用的增强,一些传统经济种类的资源受到严重威胁。有的资源潜力削弱,甚至有的生物种群的再生机制受到破坏,使其资源面临着枯竭的危险。在强大的捕捞压力下,海洋渔业资源的结构发生了很大变化。生命周期长的种类被生命周期短的种类所代替;传统的经济种类被低质的小型种类所代替。渔业组成处于不断变化和演替之中,水域生态系统的结构与功能将会发生变化,生态平衡将遭到破坏。 对各个生物种群来说,上述变化将不同程度地改变它们的生存条件。物种为了延续和生存,通过自然选择对其所处的环境进行适应性调节,因而,种群原有的生态学特征将产生一系列的变化,如生长速度提高、性成熟加快等。在渐变过程中,物种生活史选择方向也将发生变化。研究鱼类种群的变动及其生活史型的演变过程,对科学利用海洋渔业资源和保护物种的多样性,在实践和理论上都具有重要意义。  相似文献   

The nonlinear hydrodynamic model for simulating a ship steering in waves with autopilot system     

Ming-Chung Fang  Jhih-Hong Luo 《Ocean Engineering》2005,32(11-12):1486-1502

In the paper, a hydrodynamic numerical model including wave effect is developed to simulate ship autopilot systems by using the time domain analysis. The PD controller and the sliding mode controller are adopted as the autopilot systems. The differences of simulation results between two controllers are analyzed by cost function composed of heading angle error and rudder deflection, either in calm water or in waves. The results in calm water show that both controllers are tracking well for the desired route with the similar cost function value by tuning the key design parameters. However, the course tracking ability of the controller using sliding mode in waves is generally better even the cost function value is similar.  相似文献   

红海湾水域溶解氧、pH值、盐度和营养盐分布特征及相互关系研究   总被引：10，自引：0，他引：10  

王小平  贾晓平  林钦  李纯厚  甘居利  蔡文贵  王增焕  吕晓瑜 《海洋通报》1999,18(5):35-40

通过１９９８年６月对广东省红海湾海水养殖水域环境因子的调查,阐述了海水中溶解氧、盐度、ｐＨ值和营养盐的分布特征及其变化规律,并讨论了它们之间的相互关系,结果表明,溶解氧及海水ｐＨ值随温度由北（除１５￣１７号站）向南（除６号站）增高而增高。同时证实了光合作用是导致溶解氧含量和ｐＨ值增高的主要原因。而营养盐与盐度呈密度的负相关,浮游植物总量随营养盐由北向南降低而明显增高。  相似文献   

Stochastic Response Analysis of Piled Offshore Platform Excited by Stationary Filtered White Noise     

Luo Chuanxin Wu Zhiping Professor 《中国海洋工程》1997,(1)

In this paper,the analysis method of stochastic response of piled offshore platform excited bystationary filtered white noise is presented.With this method,the strong ground motion is considered asthree direction stationary filtered white noise process,the theoretic solutions of three special integrationequations are derived with the residue theorem,and the expression of response nodal displacements andmember forces of offshore platform excited by the stationary filtered white noise is put forward.Thestochastic response of a piled offshore platform excited by the stationary filtered white noise,which is lo-cated 114.3m in water depth,is computed.The results are compared with those obtained with the re-sponse spectrum analysis method and the stationary white noise model analysis method,and the corre-sponding conclusion is drawn.  相似文献   

A three-dimensional ocean general circulation model for mesoscale eddies——Ⅱ Diagnostic analysis     

Wang Ji  Moto Ikeda 《海洋学报(英文版)》1997,16(1):29-43

A three-dimensional density field associated with mesoscaie unstable waves generated by the 3-D, primitive-equation model (Wang and Ikeda, 1996) is provided to the quasi-geostrophic pressure tendency and ω-equations, and to the (ageostrophic) Q-vector equation. Diagnostic analyses, analogous to the approaches in meteorology: ω-equation and Q-vector method, are for the first time developed to examine the mesoscaie dynamical processes and mechanisms of the unstable waves propagating in the mid-latitude ocean. The weaknesses and strengths of these two diagnostic approaches are evaluated and compared to the model results. The Q-vector method is then recommended to diagnose the vertical motion associated with the mesoscaie dynamics from a hydrographic CTD (conductivity-temperature-depth) array, while the quasi-geostrophic equations produce some small-scale features (errors) in the diagnosed fields.  相似文献