中西太平洋金枪鱼围网高产渔区年间变化及其原因分析

金枪鱼类是中西太平洋海域重要的经济鱼种,其中鲣产量约占到总产量的50%。本研究利用1995-2010年16年的中西太平洋（20°S~20°N,120°E~155°W）鲣围网生产统计数据和Niño3.4海区（5°S~5°N,120°~170°W）海表温度异常数据,对这16年鲣产量最高的十大渔区（5°×5°）进行时空格局分析,讨论渔场分布差异及CPUE与ENSO指数的关系。结果表明:16年间十大作业渔区主要分布在5°S~5°N、130°~175°E区域,这十大渔区产量占总产量的比重达47.5%,其中5°S~0°、155°~160°E,0°~5°N、130°~135°E,0°~5°N、135°~140°E及5°S~0°、160°~165°E等4个渔区产量占高产渔区产量的比重均超过10%,是中西太平洋重要的鲣产区。高产渔区的分布受海表温度影响较大,在厄尔尼诺时期,高产渔区分布明显偏东,主要分布在155°~180°E海域;在拉尼娜时期,高产渔区分布明显偏西,主要分布在130°~160°E海域。     

西北太平洋海域柔鱼的产量分布及作业渔场与表温的关系研究

为了解渔业资源的时空分布及与海洋环境之间的关系 ,根据 1995～ 2 0 0 1年 6～ 11月西北太平洋海域我国鱿钓生产统计及其表温度数据 ,利用地理信息系统软件和数理统计方法分 3个海区 (14 0°E～ 15 0°E ,15 0°E～ 165°E和 165°E～ 180°E)对柔鱼产量分布、作业渔场与表温关系进行分析。研究表明 ,柔鱼产量主要分布在海区I和II ,且资源密度大 ;在海区III海域产量比重低 ,资源密度也低。 6～ 7月作业渔场广泛 ,平均日产量基本上在 1t /d以下 ;8～ 10月作业渔场集中在海区II,平均日产量基本上在 1.5t/d以上。在同一时期 ,不同海区作业渔场的最适表温有较大差异 ,并表现出自西向东逐渐降低趋势。在海区I,7～ 11月各月最适水温分别为 17～ 19℃ ,18～ 2 2℃ ,17～ 19℃ ,13～ 18℃和 10～ 14℃。在海区II ,6～ 11月各月最适水温分别为 12～ 14℃ ,14～ 17℃ ,15～ 19℃ ,14～ 18℃ ,12～ 15℃和 10～ 13℃。在海区III ,6～ 7月最适表温均为 11～ 15℃。以上结果经非参数统计的K～S检验是可信的。 3个海区柔鱼资源密度、产量分布及其作业渔场形成与各自海洋环境条件有着密切关系。     

夏季黄海南部沿海表层流刺网渔获物组成分析

结合银鲳和小黄鱼流刺网网目选择性试验,对夏季黄海南部沿海三层表层流刺网渔获物组成进行了调查分析.总共鉴定出渔获品种25种,其中优势种为梭子蟹(Portunus triuberbuculatus)、灰鲳(Stomateoidesnozawae Ishikawa)和银鲳(Stromatecoides argenteus),分别占总渔获量的59.2%,21.5%和11%,灰鲳体长分布范围为17～30 cm,优势体长范围为21～24 cm,占71.6%;银鲳体长分布范围为13～23 cm,优势体长范围为15～21 cm,占95.8%.数据分析表明,三重流刺网作业网具选择性较差,渔具兼捕种类多,捕获量大,占总渔获量的66.5%;渔获的灰鲳和银鲳处于生长型捕捞期,不利于资源的可持续利用,建议适当改良渔具,避免对其资源造成过度破坏.     

北太平洋150°E～165°E海域柔鱼渔场与表温及水温垂直结构的关系

根据 1998～ 2 0 0 1年 8～ 10月 38°N～ 4 4°N各站点水温和生产数据 ,对 15 4°E～ 15 7°E海域柔鱼作业渔场与表温及水温垂直结构的关系进行了分析。结果认为 ,38°N～ 4 4°N各站点水温结构随时间有较大差异。 8～ 9月 38°N～ 4 4°N各站点在 10 0m以内均形成明显的温跃层 ,10月份随着亲潮势力加强 ,跃层强度有所减弱 ,表层混合水可达 5 0m深 ,其温跃层基本上在 5 0～10 0m间。在 15 0°E～ 16 5°E海域 ,渔获产量主要集中在 4 2°N～ 4 4°N ,盛渔期为 8～ 9月。 8月在4 0°N～ 4 1°N海域温场最适表温为 2 0～ 2 2℃ ,在 4 2°N - 43°N海域为 16～ 19℃ ,在 4 4°N附近海域为 14～ 16℃ ,0～ 5 0m、0～ 10 0m温度梯度为 0 .16～ 0 .2 3℃ /m和 0 .11～ 0 .13℃ /m ;9月渔场最适表温、0～ 5 0m和 0～ 10 0m温度梯度为 15～ 2 0℃、0 .15～ 0 .18℃ /m和 0 .12～ 0 .14℃ /m ;10月为12～ 17℃、0 .11～ 0 .2 0℃ /m和 0 .0 9～ 0 .11℃ /m。灰色关联度表明 ,对作业渔场影响最大的是表温、0～ 5 0m温度梯度、0～ 10 0m温度梯度和纬度 ,其关联度均在 0 .8以上。渔获产量受到众多因素的影响 ,其中捕捞努力量、资源丰度、0～ 10 0m温度梯度和纬度是影响渔获量主要因子。     

基于延绳钓观察员数据的热带太平洋中东部食物网拓扑结构分析

热带太平洋是金枪鱼类、旗鱼类等渔业的主要作业海域,但目前针对此海域食物网的研究仍十分缺乏。本文根据2017年6月-11月中国金枪鱼科学观察员在热带太平洋中东部海域（13°09''N -34°27''S, 100°03''-176°17''W）采集的鱼类样品,结合胃含物及其他分析方法以35个物种间的摄食关系为基础对此海域的食物网结构进行了分析。拓扑学指标（节点强度,D;中心性指数,BC和CC;拓扑重要性指数,TI¹和TI³;关键性指数,K、K_t和K_b）和Key-Player算法（KPP-1和KPP-2）用来筛选关键种,并结合体长数据建立了基于关键种的简化食物网。肯德尔相关性分析和聚类分析结果表明,不同拓扑学指标筛选出的关键种是一致的。大多数关键种与太平洋其他海域的研究结果是相同的,如剑鱼（Xiphias gladius）、长鳍金枪鱼（Thunnus alalunga）、小吻四鳍旗鱼（Tetrapturus angustirostris）头足类和鲭属。移除5个关键种后,食物网将被离散为许多互不连接的部分（F=0.632,F^D=0.795,R^D=0.957）,表明这些物种在维持食物网结构和稳定性中的必要性。物种体长是本研究构建简化食物网时的决定性因素。研究结果有助于提高对热带太平洋食物网结构的认识,同时为进一步的生态系统动力学研究提供科学依据。     

基于GAM模型分析印度洋大眼金枪鱼和黄鳍金枪鱼渔场分布与不同环境因子关系

印度洋金枪鱼延绳钓渔业作为我国重要的远洋渔业之一,探究其渔场时空变动及与环境因子之间的关系十分必要。本文根据2016年1—6月收集的印度洋金枪鱼渔业生产数据,并结合卫星遥感获取的环境因子数据,运用ArcGIS和GAM模型分析了印度洋大眼金枪鱼和黄鳍金枪鱼渔场时空变动及与环境因子之间的关系。研究结果表明:大眼金枪鱼和黄鳍金枪鱼1—6月CPUE均呈现先减小后增加的趋势,4月均达最高值,分别为2.45尾/千钩和3.56尾/千钩,各月CPUE均存在显著性差异（P<0.001）;大眼金枪鱼和黄鳍金枪鱼渔场时空变动基本趋于一致,均为先向东北移动,后向西北移动,最后再向东北移动的趋势;GAM模型分析显示,大眼金枪鱼CPUE与模型因子的解释率为32.1%,纬度和250 m水深温度影响最显著,黄鳍金枪鱼CPUE与模型因子的解释率为37.2%,200 m水深温度影响最显著;协同分析表明,1—6月,印度洋金枪鱼延绳钓中心渔场分布于1°S~9.5°N,47°~64°E,且海表温度在29.3~30.8℃的海域。     

基于捕捞努力量的中西太平洋鲣鱼围网渔业入渔预测分析

中西太平洋是全球主要的鲣鱼（Katsuwonus pelamis）围网作业渔场,渔场极易受到海洋环境的影响,但渔场分布在众多岛国的管辖海域,如何科学指导企业准确入渔是重要的研究课题。本文根据1995-2012年中西太平洋鲣鱼围网捕捞生产统计数据,选取产量最高的22个海区（5°×5°）,结合Niño3.4区海表温度距平值（SSTA）和作业海域表温（SST）,研究中西太平洋鲣鱼围网渔场的空间分布规律,同时,以各海区捕捞努力量（作业次数）所占的百分比为入渔指标,建立基于环境因子的入渔决策模型。研究认为,中西太平洋鲣鱼捕捞努力量在纬度方向上主要分布于5°S~5°N,其累计捕捞努力量占所有作业海区的87.4%,其中以130°~140°E经度范围为最高,其捕捞努力量占22个海区的45.08%。入渔指标与Niño3.4区的SSTA、作业海域SST均符合正态模型（P<0.01）,Niño3.4区的SSTA最适值为0.25℃,作业海域SST最适值在29.5℃左右。对预测和实际排名前十的海域进行统计发现,预测值与实际值基本一致。研究认为,所建立的入渔预测模型可有效指导企业的渔业生产,为提高企业生产效率提供支撑。     

印度洋东部金枪鱼延绳钓渔业研究--大眼金枪鱼(Thunnus obesus)的生物学特征

根据作者在印度洋东部海域的延绳钓生产实践,对渔获的大眼金枪鱼群体的群体构成、摄食、繁殖等基本生物学特征进行了初步探讨.结果表明,渔获群体由纯重10～115kg、叉长80～195cm个体组成,纯重与叉长关系式w=2.000×10-5×L2.969;渔获物以3～5龄个体为主,雄性个体所占比例明显高于雌性个体,且随年龄增长雄性个体所占比例逐步提高.鱼群在该海域产卵期较长,不同年龄组性腺发育节律有明显差异.     

黄海南部黄鲫Setipinna taty(Cuvier et Valenciennes)渔业生物学研究

本文对黄海南部黄鲫群体进行了常规生物学测定.研究分析了体长组成和体重组成、体长和体重关系、性比的变化及性腺的发育情况.总样品的性比为♀/♂=0.96,体长与体重的关系式为W=1.77×10-2L2.73.优势体长为12-15cm,占74.8%;优势体重为20-40g,占67.8%;年龄组成为1-4龄,以1龄和2龄鱼占优势.     

大型深冷金枪鱼延绳钓典型渔具性能的初步研究

延绳钓是中国远洋金枪鱼渔业的主要作业方式,为探讨其渔具结构与性能特征,提高生产效率,笔者于2003年12月～2004年2月期间,在西印度洋5°30′N～6°30′S,44°00′E～62°00′E一带海域,以国内大型深冷金枪鱼延绳钓典型渔具为对象,研究了不同位置钓钩所处水深、上钓率及渔获效率.结果显示,调查期间钓钩水深分布范围约100～300 m,渔具对大眼金枪鱼上钓率以4～6组钓钩较高,对黄鳍金枪鱼则以2～4组钓钩最高.通过减少相邻浮子间钓钩数量至11枚,理论上可使钓钩水深大幅减小,并提高产量22.73%左右.     

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.     

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。     

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.     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

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.     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

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.     

INFORMATION FOR AUTHORS

<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,     

Estimation of Sediment Properties during Benthic Impact Experiments

Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges.