Variation in the distribution of yellowfin sole Limanda aspera larvae in warm and cold years in the eastern Bering Sea

Multiyear periods of relatively cold temperatures (2007–2013) and warm temperatures (2001–2005 and 2014–2018) altered the eastern Bering Sea ecosystem, affecting ocean currents and wind patterns, plankton community, and spatial distribution of fishes. Yellowfin sole Limanda aspera larvae were collected from the inner domain (≤50 m depth) of the eastern Bering Sea among four warm years (2002, 2004, 2005, 2016), an average year (2006), and three cold years (2007, 2010, 2012). Spatial distribution and density of larvae among those years was analyzed using generalized additive models that included timing of sea-ice retreat, areal coverage of water ≤0°C, and water temperature as covariates. Analyses indicated a combination of temperature effects on the location and timing of spawning, and on egg and larval survival, may explain the variation in larval density and distribution among years. During warm years, higher density and wider spatial distribution of larvae may be due to earlier spawning, an expansion of the spawning area, and higher egg and larvae survival due to favorable temperatures. Larval distribution contracted shoreward, and density was lower during cold conditions and was likely due to fish spawning closer to shore to remain in preferred temperatures, later spawning, and increased mortality. Predicted drift trajectories from spawning areas showed that larvae would reach nursery grounds in most years. Years when the drift period was longer than the pelagic phase of the larvae occurred during both warm and cold conditions indicating that settlement outside of nursery areas could happen during either temperature condition.     

Long-term variations in runoff of the Syr Darya River Basin under climate change and human activities

In this study,we analyzed the hydrological and meteorological data from the Syr Darya River Basin during the period of 1930–2015 to investigate variations in river runoff and the impacts of climate change and human activities on river runoff.The Syr Darya River,which is supplied by snow and glacier meltwater upstream,is an important freshwater source for Central Asia,as nearly half of the population is concentrated in this area.River runoff in this arid region is sensitive to climate change and human activities.Therefore,estimation of the climatic and hydrological changes and the quantification of the impacts of climate change and human activities on river runoff are of great concern and important for regional water resources management.The long-term trends of hydrological time series from the selected 11 hydrological stations in the Syr Darya River Basin were examined by non-parametric methods,including the Pettitt change point test and Mann-Kendall trend tests.It was found that 8 out of 11 hydrological stations showed significant downward trends in river runof f.Change of river runoff variations occurred in the year around 1960.Moreover,during the study period(1930–2015),annual mean temperature,annual precipitation,and annual potential evapotranspiration in the river basin increased substantially.We employed hydrological sensitivity method to evaluate the impacts of climate change and human activities on river runoff based on precipitation and potential evapotranspiration.It was estimated that human activities accounted for over 82.6%–98.7%of the reduction in river runoff,mainly owing to water withdrawal for irrigation purpose.The observed variations in river runoff can subsequently lead to adverse ecological consequences from an ecological and regional water resources management perspective.     

黄海区玉筋鱼体长和体重的关系

利用2001年春汛期间黄海区拖网和沿岸定置网玉筋鱼体长和体重资料用三种方法进行拟合,结果表明:预报性回归法所换算的体重值最接近实测值,玉筋鱼体长和体重的关系为Wt=0 7×10-5×L2 9244t(r=0 9673)。     

渤海对虾洄游和分布的研究

本文根据渤海对虾标志放流与重捕资料、渤海大面水文调查资料、渔场统计资料以及幼虾相对数量试捕资料，对渤海对虾的洄游、分布和中心渔场的位置进行了研究。根据上述资料分析表明：每年6、7月份，幼对虾在渤海各海湾及河口水深10米以内的咸淡水交汇处生活；8月上旬至9月下旬由“低盐高温”区(盐度为22-28％，水温为26-28℃)游向渤海中部东侧或辽东湾中部的“高盐低温”区(盐度为30-31％，水温为20-23℃)索饵；9月下旬之后，因季风影响浅水区水温下降，原冷水团所在的深水区反而成为相对的高温区，对虾集中于“相对高温区”中。中心渔场位置及其稳定程度取决于底层水温、盐度分布及它们的稳定状况。渤海对虾具有趋向于底层水温20℃和盐度30．5％的习性。     

春季东海南部海域幼鱼分布特征及其与环境关系的初步研究

依据1998年春季东海南部海域调查的各站稚幼鱼资料，进行了鉴定分类，并结合海洋环境进行了分析研究。在该海域获取的稚幼鱼有43种，隶属于8目、26科、27属，其中．底层鱼类有16科，24属，25种；中上层鱼类有8科、13属，18种。调查发现，稚幼鱼分布区与饵料浮游动物生物量高区基本相吻合。稚幼鱼分布比较集中的有3个区域：Ⅰ区在浙江沿岸水和台湾暖流水的交汇处，表层水温在16～18℃；Ⅱ区在浙闽沿岸水与台湾暖流水交汇处偏暖水一侧，表层水温在22～25℃；Ⅲ区在东海暖水与黑潮表层水交汇处偏暖水一侧，表层水温在22～25℃。从调查分析资料来看，在钓鱼岛附近海域可能是一个多种鱼类的产卵场。     

东海带鱼主要体征与个体繁殖力的关系

利用2003年4～8月在东海长江口渔场和舟山渔场采集的带鱼(Trichiurushaumela)样品,对东海带鱼的个体繁殖力、以及个体繁殖力与各主要体征指标的关系进行分析。结果表明,个体绝对繁殖力r、相对繁殖力r/L和r/W均呈正态分布,分别为r～N(39233　4.5810×108)、r/L～N(150.33　2940.89)和r/W～N(140.95　284.26);个体绝对繁殖力r和相对繁殖力r/L与各度量体征指标呈幂函数关系,与称量指标则为线性相关关系;个体相对繁殖力r/W与各体征指标的关系均不十分密切;个体绝对繁殖力r与肝重的关系为:r=WLiv/(6.8531×10-6WLiv 2.4326×10-5);个体绝对繁殖力r与各体征指标的多元逐步回归方程为:r=-91304.2 225.1L 18070.1Lk 389.3Lh 801.0WLiv;个体相对繁殖力r/L与各体征指标的多元逐步回归方程为r/L=14.12057 1.021L 3.484WLiv,用肛长和肝重的变化可以反映个体相对繁殖力r/L的变动。     

东海磷营养盐变动模型的建立与应用

基于磷营养盐的变动由线性趋势和周期性波动构成的假设，构建了东海磷营养盐变动模型；提出了对非等间隔时间序列实测数据求解周期等模型参数的逐步选择法。运用模型对东海磷营养盐的历史调查资料进行验证及预测检验均取得了良好效果。分析还表明，周期性成分引起的波动对东海磷酸盐变动的影响要比相应的趋势项成分大得多；模型的构成周期中并没有特别卓越的成分在其中起支配作用，决定东海磷酸盐变动的是多个时间尺度上的周期性现象的共同作用。     

东海深海底层鱼类群落及其结构的研究

本文据东海深海1981年底鱼资源调查资料,按不同站、水深带之间计算渔获物组成的相似性指数C_2,应用聚类分析方法等综合分析,结果表明:调查海区底层鱼类可区分为东海大陆架(外缘)群落、东海大陆被群落和冲绳海槽(西侧)群落等三个(主)群落。其中,东海大陆坡群落还可细分为大陆坡上部、中部和下部等三个亚群落。同时,应用种类多样性、均匀性、丰盛度和优势度指数(H~1;D、J、d和D_2),对群落结构进行分析,结果表明:H~1、D、J或d值,一般是水深浅处较小,深处较大,它们随水深的变化趋势相似;D_2值则与以上各值大致相反。作者认为除种类组成和多样性指数外,种类相似性指数也是反映生物群落结构的一个重要特征。     

不同品种大果沙棘种子特性研究

在黑龙江绥棱和内蒙古磴口试验区对俄罗斯11个大果沙棘品种和蒙古1个大果沙棘品种的种子特性进行了探讨,结果如下:(1)中国沙棘种子千粒质量、种子特征值明显低于引进大果沙棘品种.绥棱试验点供试的11个引进品种千粒质量及种子特征值均比磴口试验点高;根据种子长宽比及形状,对中国沙棘与大果沙棘进行了初步的划分.(2)大部分品种种子的宽度及长度在遗传和对环境适应上具有紧密相关性,种子厚度的遗传比较稳定,对环境的变化不敏感.(3)种子特征指标,如种子长度、宽度、长宽比3个指标与千粒质量呈极显著相关,特别是种子长度;千粒质量与百果质量呈现极显著线性相关.(4)发芽初期,中国沙棘的发芽率较引进品种高;发芽第14天时,所有供试品种的发芽率均达到了最大,发芽率高的品种有乌兰格木、丰产、巨人、绥棘1号、卡图尼礼品,发芽率≥67%.(5)不同大果沙棘种子的总黄酮、维生素E含量均具明显差异;引进品种的饱和脂肪酸显著高于中国沙棘;不同大果沙棘品种的饱和脂肪酸差异明显.     

海岛棉杂交一代主要农艺性状及经济性状的杂种优势分析

选用自育的高代品系及南疆本地培育品种作亲本,对海岛棉杂交一代主要产量性状及品质性状的杂种优势及其相关关系进行分析。结果表明,大多数组合的产量性状具有正向的中亲优势,衣分和单株铃数的超亲优势及竞争优势也大多为正向优势;各组合纤维长度、强度的杂种优势基本为正向。纤维长度和纤维强度的各杂种优势间均为正向显著或极显著相关,其他性状间的杂种优势相关关系各为不同的相关表现。