珠江八个入海口浮游桡足类的季节特征

2007—2008年在珠江八个入海口进行4个季节的生态调查数据,探讨了珠江八个入海口水域浮游桡足类的种类组成、多样性指数和丰度等指标及其与环境因素之间的关系,分析了优势种的季节数量变动及对浮游桡足类总数量的影响,并将本研究水域与珠江口外海水控制区浮游桡足类的生态特征做了比较。结果显示:周年共鉴定38种浮游桡足类,隶属3目10科23属。其中春季25种,夏季28种,秋季23种,冬季21种。优势种主要有中华异水蚤(Acartiella sinensis)、指状许水蚤(Schmackeria inopinus)、中华窄腹剑水蚤(Limnoithona sinen-sis)等种类,季节更替明显。四季平均丰度的变化趋势为春季(79.06 ind./L)>夏季(56.11 ind./L)>秋季(17.52 ind./L)>冬季(14.62 ind./L)。珠江口夏季浮游桡足类出现的种类数和物种多样性指数均为四季最高。相关性分析表明,春季高锰酸盐指数对浮游桡足类分布的影响极为显著,夏、秋季对浮游桡足类的分布影响显著的环境因子分别为溶解氧和硅酸盐。     

东海赤潮高发区春季浮游桡足类与环境关系的研究

根据2002年4-5月东海122°00′～123°30′E、29°00′～32°00′N海洋综合调查资料,对东海赤潮高发区春季浮游桡足类种类组成、优势种、群落特征及其与环境和赤潮生物的关系作了探讨.结果表明共鉴定桡足类40种,优势种有中华哲水蚤(Calanus sinicus)、真刺水蚤幼体(Eucheta larvae)、精致真刺水蚤(Euchaeta concinna)等,并以中华哲水蚤占绝对优势.桡足类总丰度均值为154.97 ind·m-3(5.00～649.85 ind·m-3),最高丰度区(＞500 ind·m-3)主要分布于长江口30°30′～31°15′N、123°15′E以东水域.多样性指数值在长江口以北是近海高于外海,长江口以南是外海高于近海.桡足类种类数与表层水温(℃)有非常显著的正相关性(R=O.713,P＜0.01).桡足类总丰度与表层水样中硅藻丰度,桡足类总丰度与夜光藻丰度呈非线形相关关系,前者可用肥力与产力模型描述,后者可用有效积温模型表达.     

大亚湾桡足类的生态学研究

根据2003年12月～2004年9月对纬度22.617°以北的大亚湾海域进行4个航次海域生态环境监测的资料,对大亚湾浮游桡足类的种类组成、生态类群、数量的季节变化和平面分布进行了分析。结果表明,所记录的54种浮游桡足类中,以红纺锤水蚤、亚强真哲水蚤、微刺哲水蚤和锥形宽水蚤的数量最丰富。桡足类种类数和丰度均以夏季最高,春季最低。通过这次调查,得出以下结论:大亚湾桡足类种类较多,是浮游动物第一大类群,但数量上次于毛颚类和枝角类;夏、秋2季是桡足类数量的高峰期,都以红纺锤水蚤占绝对优势;该次调查中大亚湾出现的浮游桡足类分属热带大洋类群、近岸低盐类群和广布类群,种类组成属印度西太平洋热带边缘区系。     

东海浮游桡足类的数量分布

根据1997-2000年在东海23°30′～33°N、118°30′～128°E水域进行的4个季节海洋调查资料,对东海浮游桡足类生态特征,分数量、群落特征、种类组成及优势种三部分从不同侧面作了探讨,本文为该研究的第一部分。结果表明,东海浮游桡足类丰度占浮游动物总丰度的55.5%,占饵料浮游动物总丰度的64.8%;秋季丰度最高、夏季次之、春季最低;平面分布不均匀,呈斑块状分布,一般东海近海高于外海和台湾海峡海域;高值区一般出现在不同水系的交汇区,其中,大陆沿岸水和东海外海水交汇区丰度值较其它混合区高。本次调查东海北部(29°～32°N、125°E以西)水域桡足类丰度约为20年前同期的1/3;东海浮游桡足类丰度的平面分布往往取决于中华哲水蚤(Calanussinicus)、精致真刺水蚤(Euchateconcina)和亚强真哲水蚤(Eucalanussubcrassus)的分布。     

El Nio/La Nia影响下北部湾海域浮游桡足类种类组成与多样性

以1998年1月至1999年5月对北部湾海域进行的4个航次生态环境综合调查的资料为基础,分析El Nio/La Nia期间北部湾四季浮游桡足类种类组成与多样性,并对其与气候及海洋水文的关系进行初步探讨。结果显示,调查期间共出现浮游桡足类122种,其中32种周年出现,以春(82种)、夏(84种)较多,秋(52种)、冬(67种)较少;四季共出现优势桡足类13种,以广温广盐类型占主导,除微刺哲水蚤(Canthocalanus pauper)外,其余12种为季节性优势种;冬、夏两季受El Nio影响较大,优势种以中型桡足类为主;秋、春季大型桡足类优势地位较高,受La Nia影响明显;北部湾浮游桡足类多样性较高。分析表明,夏季北部湾水温和盐度对浮游桡足类群落多样性有一定影响,但在其他季节,这种影响不明显。     

舟山近岸海域秋季桡足类种类组成和数量分布

为揭示舟山近岸海域桡足类的种类组成和分布现状,同时也为舟山近岸海域渔业生态系统修复提供基础数据库,于2015年11月(秋季)对舟山近岸海域(N 29.0°~31.0°,E 121.5°~123.0°)进行了浮游生物生态综合调查,并对该海域桡足类的数量分布特征进行了研究。结果表明,本次调查海域共鉴定桡足类28种,优势种为中华哲水蚤、海洋真刺水蚤、近缘大眼剑水蚤、小拟哲水蚤等11种。桡足类的总丰度为839.3个/m~3,其外海丰度均值为1300个/m~3,近岸丰度均值为320个/m~3。秋季桡足类的数量呈现近海多,近岸少的分布趋势。本次调查还发现,小型桡足类种类数占优势,可能暗示着浮游动物有小型化的趋势,造成此现象的发生可能与舟山近岸的环境变化、海域各水系的分布和消长变化有关。     

黄海北部春季和夏季浮游动物生态特性与时空分布

根据2015年3月(春季)和6月(夏季)对黄海北部辽宁近岸海域的浮游动物调查结果,分析了两个季节的浮游动物种类、生物量、丰度等群落结构特征。此次调查共鉴定出浮游动物47种,其中春季42种,夏季34种。浮游动物以浮游幼虫和小型桡足类为主。桡足类幼虫、棘皮动物幼体、桡足类幼体、洪氏纺锤水蚤、短角长腹剑水蚤、小拟哲水蚤、拟长腹剑水蚤和腹针胸刺水蚤为春季优势种;夏季浮游动物优势种依次为桡足类幼体、洪氏纺锤水蚤,拟长腹剑水蚤、短角长腹剑水蚤、桡足类幼虫、小拟哲水蚤和腹针胸刺水蚤。春季浮游动物平均生物量为512.09mg/m~3,平均丰度为15 522.18个/m~3;夏季浮游动物平均生物量为218.84mg/m~3,平均丰度为7582.39个/m~3;浮游动物生物量和丰度均为春季较高。黄海北部辽宁沿岸海域的浮游动物生物量、丰度较高。水温是影响浮游动物群落结构的重要环境因子。     

三道河水库浮游甲壳动物群落结构特征的初步研究

研究了湖北省三道河水库2007年8月至2008年4月浮游甲壳动物的群落结构及现存量的时空变化。三道河水库6个采样点(Ⅰ～Ⅵ)共鉴定出浮游甲壳动物8科、13属、21种,其中枝角类5科、9属、14种,优势种为简弧象鼻溞(Bosmina coregoni)、短尾秀体溞(Diaphanosoma brachyurum)和透明溞(Daphnia hyalin);桡足类3科、4属、7种,优势种为广布中剑水蚤(Microcyclops leuckarti)和汤匙华哲水蚤(Sinocalanus dorrii)。浮游甲壳动物年平均密度为92.6个/L,枝角类和桡足类分别为36.9个/L和55.7个/L;平均生物量为1.126mg/L,枝角类和桡足类分别为0.737mg/L和0.389mg/L。浮游甲壳动物现存量的季节变化明显,密度和生物量由高到低依次为秋季>夏季>冬季>春季。浮游甲壳动物密度的水平分布差异明显,采样点的密度和生物量由高到低为Ⅱ>Ⅵ>Ⅲ>Ⅰ>Ⅳ>Ⅴ。     

黄海南部及东海中小型浮游桡足类生态学研究Ⅱ.种类组成及群落特征

重点探讨黄海南部及东海(28°00′～34°00′N、121°00′～127°00′E)中小型浮游桡足类的种类组成和多样度以及与环境的关系.结果表明鉴定到种的中小型浮游桡足类有71种,4季皆出现的种类比例高达83.1%,种类季节变化不大明显.种数平面分布呈南部高、北部低、外海高、近海低的分布特征,种数分布与该海域水团势力消长相关,在水系交汇处,种类较多的往往位于暖流的一侧.4季共出现优势种15种(优势度Y≥0.02),主要有拟长腹剑水蚤(Oithona similis)、小拟哲水蚤(Paracalanus par)和近缘大眼剑水蚤(Corycaeus affinis)等,但在秋季,上述优势种类由尖额保猛水蚤(Aegisthus mucronatus),孔雀丽哲水蚤(Calocalanus pavo),锦丽哲水蚤(Calocalanus pavoninus)等替代.优势种更替率R值分析结果表明,黄海南部及东海调查区中小型桡足类群落所栖息的环境从夏季转至秋季的变化较大,从冬季转至夏季的变化相对较小.桡足类物种多样度(H′)、均匀度(J′)和单纯度(C)指数4季均值分别为2.58(2.27～2.99)、0.72(0.64～0.7)和0.26(0.21～0.38),H′值平面分布趋势与种数分布基本一致.     

黄海南部及东海中小型浮游桡足类生态学研究Ⅰ.数量分布

根据1981年2-11月在黄海南部及东海(28°～34°N、121°～127°E)海域进行的4个季节的海洋调查资料,对该海域中型浮游生物网采集的中小型浮游桡足类丰度作了探讨.结果表明调查区桡足类总丰度4季均值为376.40ind·m-3,夏季(846.34 ind·m-3)＞春季(338.91 ind·m-3)＞秋季(204.96 ind·m-3)＞冬季(115.41 ind·m-3).黄海南部(32°N以北)和东海(28°～32°N)调查海域4季均值分别为271.05 ind·m-3和403.59 ind·m-3,季节变化趋势与全调查区一致,但在夏季,黄海南部平均丰度(492.04 ind·m-3)明显低于东海(938.2 ind·m-3).根据优势度和回归贡献分析表明冬、春、夏3季总丰度分布主要取决于拟长腹剑水蚤(Oithona similis)、小拟哲水蚤(Paracalanus parvus)和近缘大眼剑水蚤(Corycaeus affinis)等的分布,而秋季主要取决于尖额保猛水蚤(Aegisthus mucronatus)、孔雀丽哲水蚤(Calocalanus pavo)和锦丽哲水蚤(Calocalanus pavoninus)等.文中还对影响中小型浮游桡足类总丰度分布的主要因子盐度、水温和水系等与总丰度的关系进行了探讨.     

环境DNA分析技术—一种水生生物调查新方法

掌握珍稀濒危和外来入侵物种的分布状况对于物种保护和管理十分重要。环境DNA(Environmental DNA)分析通过收集、分离和分析环境样品中的DNA来检测物种是否存在,是一种低耗、高效、高灵敏度的无损伤性物种监测新技术(e DNA)。本文综述了环境DNA技术的发展、分析方案、优势及存在的问题,主要综述了该方法在外来入侵物种足迹追踪、濒危珍稀水生生物资源调查和物种多样性分析中的研究现状,并对环境DNA分析技术在生物多样性保护研究中的应用前景进行了展望。     

三都澳大型底栖动物种类组成特点

根据2009年5月至2010年2月期间共9个航次在三都澳水域采集的底泥样品,分析三都澳大型底栖动物种类组成特点及其与养殖活动之间的关系.结果表明,三都澳水域底泥样品中共出现大型底栖动物119种,其中多毛类动物种类数量优势明显,达65种,占总种类数54.62％；甲壳动物和软体动物也是此水域常见类群,种类数分别为21种(占...     

Use of focal species in marine conservation and management: a review and critique

1. Focal species (i.e. indicators, keystones, umbrellas, and flagships) have been advocated for the management and conservation of natural environments. 2. The assumption has been that the presence or abundance of a focal species is a means to understanding the composition and/or state of the more complex community. 3. We review the characteristics of focal species, and evaluate their appropriateness and utility judged against conservation objectives. 4. It appears that indicator species (of both composition and condition) may be of greatest general utility, and that several types of focal species may exhibit useful indicator properties. Copyright © 2001 John Wiley & Sons, Ltd.     

Population crash in Lesotho's endemic Maloti minnow Pseudobarbus quathlambae following invasion by translocated smallmouth yellowfish Labeobarbus aeneus

1. A genetically distinct population of the Maloti minnow Pseudobarbus quathlambae (Lesotho's only endemic fish) is known only from the Mohale catchment, and was formerly abundant in the Senqunyane, Bokong and Jorodane rivers which flow into Mohale Reservoir.
2. Situated ~4 km downstream of Mohale Reservoir, the Semongkoaneng waterfall has historically prevented larger fish species from moving upstream into areas inhabited by P. quathlambae. After the filling of the Mohale Reservoir in 2003, an inter‐basin transfer (IBT) linking it to Katse Reservoir was opened and in 2006 the smallmouth yellowfish Labeobarbus aeneus, a larger more aggressive species, was recorded in the reservoir, presumably introduced via the IBT.
3. The objectives of the present study were to: (1) establish whether any additional non‐native fish species were present in the Mohale catchment; (2) ascertain whether L. aeneus has dispersed into the rivers flowing into Mohale Reservoir; and (3) gauge whether the Mohale population of P. quathlambae is in decline. Twenty‐eight sites situated on major rivers flowing into the reservoir, and four sites in the reservoir itself, were surveyed to evaluate changes in fish populations and habitat quality.
4. Results indicate that P. quathlambae has all but disappeared from its natural range: only five individuals were recorded in the Jorodane and Bokong rivers, and none were recorded in the Senqunyane River – a former stronghold for the species. On the other hand, L. aeneus was recorded in all three rivers and is probably responsible for the decline of the P. quathlambae population, given that there does not appear to have been major deterioration in habitat conditions. Another non‐native fish, the Orange River mudfish Labeo capensis, was recorded in the Mohale catchment for the first time. Urgent conservation action is required to prevent the Mohale lineage of P. quathlambae from becoming extinct.

Copyright © 2016 John Wiley & Sons, Ltd.     

On species and speciation with reference to the fishes

The nature of species and the processes in which they participate are subjects of continuing debate among evolutionary biologists. I begin by examining how ichthyologists treat species empirically. Such treatments provide a pattern of species and their relationships over time and space. I suggest that this empirical record points to a predominant mode of speciation: vicariant, Model I, allopatric speciation. I also suggest that species are real and that they are individuals. There is a single species concept, the evolutionary species concept (ESC), that best captures the way we think about fish species. This concept is also well integrated with the manner in which species are treated in Phylogenetic Systematics and with the philosophical concept that species are particulars rather than universals.     

黄河口及其邻近水域浮游动物群落结构特征及其季节变化

根据2013年8月、10月和2014年2月、5月在黄河口及其邻近水域4个航次的调查数据,分析了该海域浮游动物的种类组成、数量变动、优势种、种类多样性及其季节变化。本次黄河口及其邻近水域调查共鉴定浮游动物43种,其中原生动物、毛颚动物、尾索动物和栉水母各1种,刺胞动物8种,浮游甲壳类18种,浮游幼体及鱼卵、仔稚鱼共13种(类)。浮游动物的平均丰度为2115.64 ind/m~3,不计夜光虫的平均丰度为95.93 ind/m~3,其中浮游甲壳类占71.43%。浮游动物丰度存在显著的季节变化,数量高峰出现在春季(5月),其次为冬季(2月)、秋季(10月)和夏季(8月)。毛颚动物强壮箭虫(Sagitta crassa)和双刺纺锤水蚤(Acartia bipinnata)、小拟哲水蚤(Paracalanus parvus)等桡足类为夏、秋、冬三个季节的主要优势种,夜光虫(Noctiluca scintillans)为春季的绝对优势种。浮游动物群落物种丰富度指数(D)、Shannon-Wiener指数(H')和均匀度指数(J')的变化趋势一致,表现为夏秋季高,冬春季低。黄河口及其邻近水域浮游动物的群落结构特征具有明显的季节变化;桡足类和浮游幼体是主要类群,对该水域浮游动物的数量变动及种类多样性的变化具有较大影响。     

An introduction to species concepts and speciation of fishes

More than 22 different species concepts have been proposed. The concepts in general reflect the philosophical outlook, particular expertise, and the groups on which the authors are working. The full‐length papers in this special issue dedicated to species concepts relative to fishes are based on presentations by the authors at the 2001 annual meeting of the American Society of Ichthyologists and Herpetologists at University Park, Pennsylvania, USA and generated much discussion on the topic of what constitutes a species.     

Heads you win,tails you lose: Life‐history traits predict invasion and extinction risk of the world's freshwater fishes

1. Freshwater fishes have the distinction of being both a highly imperilled taxonomic group as well as one that has produced many invasive species with widespread ecological impacts. Faced with the difficult task of identifying those species with the greatest need for management action, ecologists have turned to using predictive suites of ecological and life‐history traits to provide reasonable estimates of fish invasion and extinction risk. Whether traits associated with invasiveness are the inverse of those associated with imperillment, known as the ‘two‐sides‐of‐the‐same‐coin’ hypothesis, remains unclear.
2. A global trait analysis (including maximum total body size, longevity, size at maturation, age at maturation, fecundity and egg size) for 6293 freshwater fishes was conducted to examine the trait correlates of species proneness to invasion or extinction. A meta‐analytical procedure was deployed using univariate and multivariate trait analyses that accounted for the effects of shared phylogeny.
3. Mean trait differences (measured as Hedges' d effect size) were found between invasive and threatened species when compared with native species, thus supporting the two‐sides‐of‐the‐same‐coin hypothesis for freshwater fish. Invasive species were characterized by larger body size, greater longevity, delayed maturation and higher fecundity than threatened species. Furthermore, invasive species were found to display greater trait variability compared with threatened species, suggesting that different traits may be selected at different stages of the invasion process (from pathway entrainment to establishment) whereas more specific trait combinations may predispose species to higher extinction risk.
4. The present study demonstrated a strong trait basis to global‐scale invasion risk and extinction vulnerability for freshwater fishes. Given that both time and resources are too limited for detailed species‐by‐species assessments, the results suggest that trait correlates provide a reasonable estimate of invasion and extinction risk that can inform more targeted and proactive conservation strategies.

     

Species concepts and speciation of fishes: concluding remarks

The definition of the species category has stimulated more debate than perhaps any other topic in the biological sciences. There are currently more than 22 different species concepts and the debate continues on which concepts apply to all organisms, which concepts are operational and which concepts should be used in specific circumstances. The first major division of the types of concepts depends on whether one views species as constructs that exist for ordering biodiversity and information retrieval (i.e. classes), or views species as ontological individuals that exist in nature. If species are categories that can be defined, then theoretically, a single species can arise more than once in different places or at different times. If, on the other hand, species are individuals, then they are historical events, monophyletic and each species is unique.     

广西桂林青狮潭水库鱼类物种组成及多样性分析

2015年4月至2016年1月按季度对青狮潭水库库区鱼类资源进行了调查,采集鱼类样本3 750尾(153.28kg),经鉴定有鱼类32种,隶属于5目12科27属,其中以鲤形目鱼类为主,分别占总物种数和总个体数的53.13%和61.92%。相对重要性指数分析表明,鲫(Carassius auratus)、■(Hemiculter leucisculus)和鲤(Cyprinus carpio)为优势种;鱼类多样性分析结果显示,各季节丰富度指数(D)为2.58~3.52,Shannon-Wiener多样度指数(H')为1.62~1.92,Pielou种类均匀度指数(J')为0.53~0.63,其中夏季多样性最高、冬季相对较低;空间上,鱼类多样性呈现从河流入库口、近岛水区向湖心降低趋势。聚类及相似性分析(ANOSIM)表明,鱼类群落组成时空差异不明显。