新疆阿勒泰地区额尔齐斯河和乌伦古河流域鱼类多样性演变和流域健康评价

为了解阿勒泰地区额尔齐斯河和乌伦古河流域的鱼类多样性现状和历史演变,本研究于2013–2016年间在该流域的鱼类多样性进行了连续调查,并结合历史资料和标本,以Margalef丰富度指数、Shannon-Wiener多样性指数、Pielou均匀度指数分析评估了流域内鱼类的多样性水平和时空变化。该流域历史上分布有土著鱼类23种,当前记录到19种,流域内还有外来鱼类15种。阿勒泰鱼类的区系组成以鲤科种类为主,其中特有和珍稀濒危物种占比高,具有重要的保护价值。多样性指数计算结果显示,2013–2016年鱼类多样性情况整体稳定,额尔齐斯河鱼类物种数多于乌伦古河。研究还基于鱼类生物完整性指数(Fish Index of Biological Integrity,F-IBI)对34个采集点的河流健康状况进行了评价,结果显示额尔齐斯河流域大多数调查点的健康状况处于"亚健康"或"一般"水平,乌伦古河流域多数调查点的健康状况处于"健康"水平。水利工程、外来物种、过度捕捞是影响阿勒泰地区鱼类多样性的重要因素。未来应通过水利工程的联合调度、下泄合理生态流量、布设鱼类通道、规范养殖渔业、严控外来物种、本地土著鱼类的人工增殖放流,以及合理的就地保护措施对阿勒泰地区的鱼类多样性加以保护,提升水体健康程度。

上海苏州河治理中鱼类多样性及群落结构变化

为了评估近20年来上海苏州河环境综合整治过程中鱼类多样性的变化状况,本文于2019年6月(夏季)和9月(秋季)对苏州河13个断面的鱼类样本进行了采集,对鱼类多样性和群落结构作了分析。结果显示,2次采集共获得鱼类样本10,102号,隶属于8目15科37属45种。夏季和秋季,上游8个断面的鱼类均为36种,下游5个断面则为12种和15种。从上游到下游,Shannon-Wiener多样性指数(H’)、Margalef种类丰富度指数(D)和Simpson优势度指数(C)总体呈逐渐降低的趋势。相对重要性指数(IRI)显示,夏秋两季上游断面共同的优势种为似鳊(Pseudobrama simoni),下游为鲫(Carassius auratus)和泥鳅(Misgurnus anguillicaudatus)。丰度生物量曲线表明,全河段鱼类群落结构总体上并不稳定,特别是夏季的下游河段。Cluster聚类和非参数多维标度排序分析可明显将鱼类群落分为上游群组(I)与下游群组(II),似鳊、泥鳅、鲫、光泽黄颡鱼(Pelteobagrus nitidus)和兴凯鱊(Acheilognathus chankaensis)等是造成群组间差异性的主要分歧种。与2001年的43种、2006年的28种相比,本次调查的物种数出现了明显回升,特别是下游河段。这种上游鱼类向下游迁移的趋势,预示着下游中心城区与上游郊区河段的水质差别正在缩小,水生态系统恢复迹象明显。本文认为,上下游之间鱼类群落结构差异的缩小以及翘嘴鲌(Culter alburnus)、红鳍原鲌(Cultrichthys erythropterus)、棒花鱼(Abbottina rivularis)、子陵吻虾虎鱼(Rhinogobius giurinus)等在下游河段的出现,可作为苏州河综合整治效果的重要生态标志。

南水北调中线工程对海河流域鱼类入侵风险分析

海河流域是南水北调中线工程的受水区之一,为评估中线工程引发海河流域鱼类入侵的风险,本研究统计了南水北调引水区和受水区海河流域鱼类物种多样性差异,采用水生生物入侵能力筛查系统(aquatic species invasiveness screening kit,AS-ISK)和外来鱼类入侵风险评估体系筛选引水区有入侵风险的鱼类物种,并用MaxEnt模型预测有入侵风险的鱼类物种在海河流域的潜在适生区。结果表明,丁鱥(Tinca tinca)、陈氏新银鱼(Neosalanx tangkahkeii)和大口鲇(Silurus meridionalis)是具有高入侵风险的鱼类,另有3种鱼类具有中入侵风险,均需重点监控;而具入侵风险鱼类的适生区预测结果表明,海河流域南部的徒骇马颊河水系、海河水系的漳卫南运河以及环渤海地区的河流是极易发生鱼类入侵的水域。因此在海河流域高入侵风险水域应开展持续性的水生生物监测,针对具有高入侵风险的鱼类应进行早期筛查,此外在水资源利用和分配上应加强管理,从源头上杜绝鱼类入侵的发生,还应尽快开展针对东线工程的鱼类资源调查和入侵风险评估工作。

Blubber fatty acid compositions in different geographic populations of finless porpoise in Chinese waters:implications for thermal adaptation

The stratification of blubber fatty acids(FAs)is a widely used strategy in marine mammals and can be influenced by many factors,including their diet,environmental temperature,and physiological status.There are 3 distinct finless porpoise species/subspecies in Chinese coastal and inland waters in a wide range from 20°N to 40°N.The biochemical stratification of the blubbers of finless porpoises in different regions may provide valuable information for understanding their environmental adaptations.The FA compositions of 4 geographic populations of finless porpoise(FP)collected from the Bohai Gulf,East China Sea,South China Sea,and Yangtze River were therefore analyzed and compared.The blubber FA compositions of finless porpoises were dominated by∑MUFAs,followed by∑SFAs and∑PUFAs,and were generally consistent with those of other cetaceans.The blubber of finless porpoises was significantly stratified with increasing levels of∑MUFAs and decreasing levels of∑SFAs and∑PUFAs from the inner to the outer layers.The 3 marine populations shared more similarities in their FA compositions and stratifications compared to the freshwater porpoises,particularly regarding the PUFAs in the inner layers,which might have been mainly influenced by the diet compositions of marine and freshwater porpoises.Contrary to what was expected,in the 3 marine populations,the SFA and MUFA levels showed opposite correlations(negative and positive,respectively)with habitat temperatures,possibly indicating an adaptation mechanism in finless porpoises characterized by a trade-off between the insulation and fluidity properties of the blubber through the adjustment of the compositions and gradients of MUFAs and SFAs across the blubber depth in response to environmental temperature/latitude changes.

Population genetic structure in wild and aquaculture populations of Hemibarbus maculates inferred from microsatellites markers

The objective of this study was to investigate 4 aquaculture populations Shanghai(SH),Hangzhou(HZ),Kaihua(KH)and Xianju(XJ)and one wild population Yingshan(YS)of spotted barbell(Hemibarbus maculates)to assess their genetic diversity level and investigate the genetic structure of the populations.The dendrogram and STRUCTURE revealed that the populations XJ,KH,and HZ jointly formed one cluster,to which the populations SH and YS were sequentially adhered.The genetic diversity of the cultured populations maintained better,possible due to favourable hatchery conditions that decreased the effect of environmental selection present in wild populations.The results of the present study will contribute to the management of spotted barbell genetic resources,but also demonstrates how the genetic diversity of freshwater species is vulnerable to human activity.

Radiation dose rate estimates to marine biota resulting from the routine radioactive releases of the nuclear power plants in Daya Bay

Five marine organisms in Daya Bay are selected for estimating the dose rates. Internal exposure and its 5 pathways are also considered. The concentrations of 43 kinds of background and additional radionuclides in seawater are from the survey of background radioactivity and the prediction of routine radioactive releases of the 4 reactors. Point source dose distribution functions are used to estimate the dose rates to various organisms from a and β radiation.