小黄黝鱼繁殖期与非繁殖期的两性异形

两性异形可能在促进入侵种成功入侵过程中扮演重要角色而促使研究者进行广泛的探讨。本文利用传统形态性状测量及框架性状分析方法定量研究了滇池流域典型入侵鱼类小黄黝鱼Micropercops swinhonis繁殖期与非繁殖期的两性异形特征,为系统研究小黄黝鱼的繁殖生态与入侵机制的关系奠定基础。研究结果显示,小黄黝鱼种群在5—6月出现世代交替,可以划分出5月前的世代Ⅰ和6月后新成熟的世代Ⅱ2个繁殖群体。这2个繁殖群体繁殖期雄鱼体长均显著大于雌鱼,提示小黄黝鱼是偏向于大个体雄性的两性异形物种。非繁殖期,小黄黝鱼雌雄体长差异无统计学意义。单因素方差分析显示,小黄黝鱼雌雄个体无论繁殖期还是非繁殖期均在多个测量参数中呈现显著差异。主成分分析显示,世代Ⅰ繁殖群体繁殖期雌雄鱼在第二主成分PC2轴上显著分离,尾柄高/体高、腹鳍起点-臀鳍起点/体长等是导致两性形态差异的主要指标,提示雄鱼尾柄增大及雌鱼腹腔增大以提高两性的繁殖成功率等策略是促使两性异形的重要因素;世代Ⅱ繁殖群体在第一主成分PC1轴上显著分离,全长、体长、尾柄长/头长、尾柄高/体长、头宽/体长、胸鳍起点-臀鳍起点/体长等与生长及腹腔增大有关的指标是导致两者形态差异的主要因素;非繁殖期雌雄鱼形态性状差异不明显。判别分析结果则进一步支持了雌雄鱼形态性状差异繁殖期明显、非繁殖期不明显的结论。小黄黝鱼两性异形与提高其繁殖输出及后代早期存活率密切相关,对其入侵与种群扩张有积极意义。     

四川裂腹鱼和重口裂腹鱼形态差异的多元分析

通过聚类分析、判别分析和主成分分析3种多元分析方法,对乌江总溪河89尾四川裂腹鱼(Schizothorax kozlovi)和岷江青衣江33尾重口裂腹鱼(S.davidi)的10个常规可量性状与20个框架性状进行了比较研究。聚类分析结果显示,3次采集的四川裂腹鱼聚为一支,而重口裂腹鱼单独为一支;主成分分析结果显示,提取的8个主成分对总方差的累计贡献率为73.762%,贡献率大的性状集中在吻端和躯干后侧;通过两次判别分析,最终建立四川裂腹鱼和重口裂腹鱼两个判别方程,综合判别率为100%。研究结果显示,四川裂腹鱼和重口裂腹鱼是独立的两个种,在形态上的主要差异体现在吻端和躯干后侧,运用多元分析方法能有效地将其区分开来,而3次采样的四川裂腹鱼为同一种群。     

河南省淮河流域鳑鲏亚科5种鱼形态差异分析

为进一步从可量性状比较中华鳑鲏(Rhodeus sinensis)、越南鱊(Acheilongnathus tonkinensis)、大鳍鱊(A. macropterus)、兴凯鱊(A. chankaensis)和斑条鱊(A. taenianalis)的种间形态差异, 丰富鳑鲏亚科鱼类的形态分类特征, 研究采用多变量形态度量学方法对河南省淮河流域这5种鱼的形态进行比较分析。结果表明: 这5种鱼在体宽/体长、头长/体长、吻长/体长、尾柄长/体长、背鳍基底长/体长、腹鳍长/体长、臀鳍长/体长和头长/吻长8个比值性状上存在极显著性差异(P< 0.01), 在全长/体长、体高/体长2个比值性状上存在显著性差异(P<0.05), 这些差异主要集中在鱼体的头部、尾部和鳍等部位。主成分分析、聚类分析和判别分析显示5种鱼存在显著性形态差异, 斑条鱊与越南鱊的差异程度最大, 与大鳍鱊差异程度最小。判别分析获得的判别准确率在82.35%—100.00%变化, 可以从一定的角度区分这5种鱼。     

濒危鱼类稀有白甲鱼沅江种群与西江种群形态度量学性状的差异性

分别以采自沅江水系142例和西江水系92例稀有白甲鱼标本为材料,采用差异系数法、方差分析法、判别分析法和主成分分析法,研究了稀有白甲鱼沅江种群、西江种群包括10个可数性状和31个比例性状等形态度量学性状的差异性.方差分析表明,2个种群之间共有6个可数性状和27个比例性状存在着显著性差异(P＜0.05).判别分析筛选出了9个对区分2个种群贡献较大的比例性状,并建立了2个种群的判别函数式.主成分分析显示,稀有白甲鱼种群鱼体沿背腹轴、头尾轴分别有16和6个比例性状表现出了明显的变化,在尾部有2个比例性状差异明显.可见2个种群之间形态度量学性状已显示了明显的分化.这可能是两个种群长期隔离,在不同水系生态环境中产生了适应性进化的结果.然而,差异系数的计算结果表明,两个种群之间形态度量学性状的差异尚未达到亚种分化的水平.     

华南沿海地区西部入海水系中间黄颡鱼的形态变异及地理分化

为探讨不同水系中间黄颡鱼(Pelteobagrus intermedius)的形态差异及地理分化问题,采用形态学方法, 测量12个水系中间黄颡鱼150尾样本的18个形态性状,进行主成分分析.其结果显示,前3个主成分累积贡献率为58.918%,并可将这12个水系的群体分为3簇.华南沿海地区西部诸独立入海小水系中的中间黄颡鱼群体与海南岛群体之间的相似性大于与西江干流群体的相似性.防城港地区3条直接入海的小水系的群体在形态特征上已发生了一定程度的分化,其分化主要表现在吻、眼和尾的变异.     

基于耳石几何形态测量学的长江安徽江段刀鲚群体识别研究

为了解长江安徽江段刀鲚耳石的形态特征和尝试识别不同群体,研究选用基于地标点的几何形态测量学手段,对不同年份采于长江安徽安庆、铜陵江段长颌鲚和短颌鲚2种生态表型的5个群体刀鲚矢耳石形态差异性进行了比较研究。基于12个地标点,将其坐标进行相对扭曲主成分分析及判别分析,经薄板样条分析和网格变形,使其耳石形态变异矢量可视化。结果显示,在相对扭曲主成分分析中,提取的地标点中多为Ⅱ类地标点,其贡献率为69.48%,说明Ⅱ类地标点是耳石形态差异的主要来源。5个群体刀鲚判别分析的综合判别准确率为95.6%,表明这些刀鲚群体耳石形态的差异总体显著。这种差异显著性尤其存在于长颌鲚与短颌鲚生态表型间及长颌鲚和短颌鲚不同群体间,显示出刀鲚不同生态表型分化及其群体间差异性已可体现在耳石的形态特征上。上述发现可为长江十年禁渔前后安徽江段刀鲚群体组成和群体差异性的客观评价提供理论支撑。     

华南沿海地区西部入海水系中间黄颡鱼的形态变异及地理分化

为探讨不同水系中间黄颡鱼 (Pelteobagrus intermedius) 的形态差异及地理分化问题,采用形态学方法, 测量12个水系中间黄颡鱼150尾样本的18个形态性状,进行主成分分析。其结果显示,前3个主成分累积贡献率为58.918%,并可将这12个水系的群体分为3簇。华南沿海地区西部诸独立入海小水系中的中间黄颡鱼群体与海南岛群体之间的相似性大于与西江干流群体的相似性。防城港地区3条直接入海的小水系的群体在形态特征上已发生了一定程度的分化,其分化主要表现在吻、眼和尾的变异。     

细鳞斜颌鲴三个群体形态差异

将传统形态学数据与现代框架数据相结合,分析了细鳞斜颌鲴3个群体(龙窝湖群体、梁子湖群体和淮河群体)的形态差异,探讨了它们的形态亲缘关系。方差分析表明,3个群体间8个可数性状参数差异不显著(P0.05)。聚类分析显示,龙窝湖群体与梁子湖群体首先聚为一类,然后再与淮河群体相距。在28个测量参数中挑选7个对判别贡献较大的参数建立判别函数,判别效果极显著(P0.01),判别准确率93.55%～100%,综合判别率96.81%,通过判别函数可将这3个群体很好地区分开。主成分分析概括出方差贡献率较大的3个主成分,累计方差贡献率为82.99%。主成分1主要反映鱼体躯干部的形态变化,方差贡献率52.83%;主成分2主要反映鱼体头部的形态变化,方差贡献率22.22%;主成分3主要反映鱼体尾柄部的形态变化,方差贡献率7.94%。主成分1和2二维平面图显示,虽然龙窝湖群体和梁子湖群体有少量重叠区域,但3个群体还是可以清晰分开的。3个群体间形态性状的差异系数均小于1.28,群体间尚未达到亚种差异水平。     

四种杂交组合奥尼罗非鱼及其亲本的生长对比研究

通过RFID电子标记注射、跟踪和生长性状测量,对2个奥利亚罗非鱼品系(ZZ、AA)、2个尼罗罗非鱼品系(XX、EE)自交群体及其杂交奥尼罗非鱼4个群体(XZ、XA、EZ、EA)进行生长对比研究,罗非鱼亲本来自国家罗非鱼产业技术体系研发中心。结果表明:XZ、XA、EZ、EA四个奥尼罗非鱼群体雄性率均达94%以上,全长、体长、头长、体高等性状特征值显著高于亲本品系(P<0.05),奥尼罗非鱼的生长速率相对其亲本品系具有一定的优势,同时4个奥尼群体间生长性状特征值也存在显著差异(P<0.05);生长性状相关分析显示罗非鱼各配组群体的体质量与尾柄长相关性较低(0.690—0.846),与全长、体长、体高、体厚相关性较高;对罗非鱼各配组群体的比例性状进行主成分分析,第1主成分主要代表BS、HS、CDS、BWS性状特征,第2主成分主要代表TS、HS、CLS性状特征,通过第1、第2主成分作图可将AA与其他6个罗非鱼配组群体有效区分。     

凡纳滨对虾各月龄性状的主成分与判别分析

为了研究凡纳滨对虾各性状增长规律和判定最佳生长季节凡纳滨对虾的体格与月龄的关系,选择1～6月龄凡纳滨对虾各1000只,选择全长、体长、第一腹节背高、第三腹节背高、第一腹节背宽、头胸甲长和体重共7个性状,进行主成分与判别分析.结果表明:各月龄凡纳滨对虾性状之间均呈现显著的正相关(P<0.01), 其中以全长与体长的相关性最为明显,1月龄凡纳滨对虾体重与形态性状的相关系数较小.各月龄凡纳滨对虾的主成分有所不同,1～2月龄凡纳滨对虾的第一主成分为长度因子,第二主成分为宽度因子,第三主成分为高度因子;3月龄凡纳滨对虾的第一主成分与1～2月龄凡纳滨对虾一致,但第二主成分为高度因子,第三主成分为体重因子;4～6月龄凡纳滨对虾的第一主成分为体重因子,第二主成分为高度因子,第三主成分为宽度因子.1～3月龄凡纳滨对虾形态性状的增长优先于体重, 4～6月龄凡纳滨对虾体重优先于形态性状的增长.错过最佳生长季节的凡纳滨对虾的与体格大小相符的月龄可通过建立的判别式来判断,总的判别准确率为98.98%,其中2～4月龄凡纳滨对虾的判别准确率为100%.     

Stock structure analysis of Labeo rohita (Hamilton, 1822) across the Ganga basin (India) using a truss network system

In this study the intraspecific variation of wild Labeo rohita was investigated on the basis of morphometric characters using the truss network system constructed from the fish body. Altogether 435 fish samples were collected from six drainages of the Ganga basin in India. Data were subjected to principal component analysis, discriminant function analysis and univariate analysis of variance. The first principal component (PC1) explained 47.88% of the total variation, while PC2 and PC3 explained 17.22 and 8.33%, respectively. The step‐wise discriminant function analysis retained three variables that significantly discriminated the populations. Using these variables, 62.3% of the original groups were classified into their correct samples and 53.1% of the cross‐validated groups omitting one procedure were classified into their correct samples. Misclassification was higher for samples from the River Gomti (28.6%). Of the total of 31 transformed truss measurements, 30 exhibited significant differences among populations. These findings indicate the presence of six different stocks of L. rohita in the Ganga basin.     

Morphological variability between wild populations and inbred stocks of a Chinese minnow, Gobiocypris rarus

Gobiocypris rarus, a small, native cyprinid fish, is currently widely used in research on fish pathology, genetics, toxicology, embryology, and physiology in China. To develop this species as a model laboratory animal, inbred strains have been successfully created. In this study, to explore a method to discriminate inbred strains and evaluate inbreeding effects, morphological variation among three wild populations and three inbred stocks of G. rarus was investigated by the multivariate analysis of eight meristic and 30 morphometric characters. Tiny intraspecific variations in meristic characters were found, but these were not effective for population distinction. Stepwise discriminant analysis and cluster analysis of conventional measures and truss network data showed considerable divergence among populations, especially between wild populations and inbred stocks. The average discriminant accuracy for all populations was 82.1% based on conventional measures and 86.4% based on truss data, whereas the discriminant accuracy for inbred strains was much higher. These results suggested that multivariate analyses of morphometric characters are an effective method for discriminating inbred strains of G. rarus. Morphological differences between wild populations and inbred strains appear to result from both genetic differences and environmental factors. Thirteen characters, extracted from stepwise discriminant analysis, played important roles in morphological differentiation. These characters were mainly measures related to body depth and head size.     

Morphometric and meristic variation in Galician threespine stickleback populations,northwest Spain

Synopsis We evaluated morphological differentiation among populations of threespine stickleback, Gasterosteus aculeatus, from the Limia and Miño basins (Galicia, NW Spain), the river Karup (Denmark) and Aiguamolls de l’Empordà (Girona, northeast Spain), using multivariate analysis of morphometric and meristic characters. Multivariate discriminant analysis and hierarchical cluster analysis uncovered significant differences among the four main groups, between the two groups from Galicia and among populations within the Miño basin. The stickleback from Galicia differed from the Danish group in head and body armour characters. Between the Miño and Limia groups, we found differences in both head and body proportions as well as in number of gill rakers. Within the Miño basin populations varied with respect to head and body armour traits and the number of lower gill rakers. Clustering analysis divided these populations into two groups based on the latter trait: fish from the upper section of river Miño and tributaries (a lower number of lower gill rakers) and fish from the central and lower reaches of the river. Overall, morphometric traits were more useful than meristic ones; however, the two types of data provided congruent information about the morphological differentiation of stickleback populations.     

Geographic variation in Leporinus friderici (Bloch) (Pisces: Ostariophysi: Anostomidae) from the Paraná-Paraguay and Amazon River basins

Morphological variation among populations of Leporinus friderici (Bloch), an anostomid fish of widespread neotropical distribution, has been hypothesized but never conclusively demonstrated. We used multivariate procedures to examine patterns of morphometric variation among populations of L. friderici from three South American biogeographic regions: the Paraná-Paraguay River and Amazon River basins of Brazil, and the Marowijne River basin of Suriname. Samples from the southern Paraná-Paraguay basin are completely distinct from the northern Amazonian and Suriname regions in principal components analysis, primarily on the basis of body elongation and orbit differcnces. Samples from the two northern regions were separated in a size-free canonical variates analysis by differences in relative body depth. These results emphasize a need for further studies of neotropical fish species with similar distribution patterns.     

Morphometric variation of snakehead fish,Channa punctatus,populations from three Indian rivers

The present study was undertaken with the objective to investigate the intraspecific variation of Channa punctatus on the basis of morphometric characters using the truss network system that was constructed from the fish body. Fish samples were collected from the Narora (n = 62) and Kanpur sites (n = 46) of the Ganga River, the Firozabad site in the Yamuna River (n = 66) and at the Lucknow site of the Gomti River (n = 60). Data were subjected to principal component analysis, discriminant function analysis and univariate analysis of variance. The first principal component (PC I) analysis explained 47.75% of total variation while PC II and PC III explained 8.18 and 7.48%, respectively. The step‐wise discriminant function analysis retained seven variables that significantly discriminated the populations. Using these variables 81.85% of the original groups were classified into their correct samples. Misclassification was higher for the samples from Ganga River (19.6% at the Kanpur site and 19.4% for the Narora site). Of the total 27 transformed morphometric measurements, 23 exhibited significant differences among the populations. These findings indicate the presence of different stocks of fish from the three rivers.     

珠江水系鱼类群落多样性空间分布格局

珠江是我国南方第一大河,是我国重要淡水渔业生产基地和水生生物资源基因库。珠江鱼类在维持生物多样性、提供鱼类种质资源方面举足轻重。但是到目前为止,关于其鱼类空间分布格局的研究甚少。特别是近几十年来各种水工建设和过度捕捞使得渔业资源急剧衰退,鱼类空间分布的研究显得尤为重要。2015年对珠江全流域13个站位进行了全面调查,共采集渔获物10119尾,隶属于94种72属17科。鲤科鱼类占显著优势,其次种类较多的依次为鲿科、鳅科。采用非度量多维标度排序(NMDS)方法对鱼类群落空间分布特征进行了分析,结果表明珠江鱼类被划分为3个类群,即以餐、南方拟餐、黄颡鱼等小型鱼类为主的中上游类群、以赤眼鳟、鲮鱼、广东鲂等中型鱼类为主的中下游类群和以罗非鱼为主的重要支流类群。同时发现中下游物种多样性高,上游及河口江段多样性低的格局。采用冗余分析方法(RDA)分析了鱼类多样性与环境因子的关系,发现年均气温、降雨量、年均径流量、河流宽度与透明度是珠江水系河流鱼类群落结构差异的主要影响因子,其中年均气温是影响鱼类群落分布的最关键因子之一。与历史资料对比后发现,珠江鱼类种类明显减少、空间分布也发生了巨大改变。研究是珠江水系野生渔业资源长期调查的一部分,研究结果将对渔业资源的多样性保护和可持续利用具有指导意义。     

Molecular differentiation of species of the genus Zungaro (Siluriformes, Pimelodidae) from the Amazon and Paraná-Paraguay River basins in Brazil

Fish species of the Zungaro genus (Siluriformes, Pimelodidae) are amongst the largest migratory fish in Latin America and have considerable economic importance for commercial fishing in Brazil. However, natural populations of this large catfish are experiencing a severe decline. There are significant taxonomical inconsistencies for this fish. Two geographically separated species of the fish were initially described, one endemic in the Amazon and another in the Paraná-Paraguay River basins. A taxonomic review had recently proposed that there is only one Zungaro species in Brazil, based on morphological data. We made a molecular study of Zungaro populations in an attempt to solve taxonomical inconsistencies and to analyze genetic diversity in natural populations of this genus. We analyzed two regions of the mitochondrial DNA (the control region and the ATPase 6 gene region) of individuals sampled from the Paraná-Paraguay River and Amazon River basins. Analyses based on p-distances and maximum likelihood phylogenetic models showed a genetic difference between populations corresponding to different species. Genetic differentiation between Zungaro populations was at the same level as that observed between other Siluriformes species, using the same DNA sequences. We conclude that Zungaro species of the Paraná-Paraguay River basin do not belong to the same species found in the Amazon basin. This finding has a significant implication for conservation of this fish, given that populations are disappearing at a high rate in the Paraná-Paraguay River basin, mainly due to impoundments.     

珠江源头入侵种波氏吻虾虎的遗传多样性分析

为了解入侵种波氏吻虾虎Rhinogobius cliffordpopei在珠江源头地区的遗传多样性分布特征及其影响成因,本研究以线粒体细胞色素b(cyt b)基因为分子标记,对珠江源头的9个水库自然种群进行了遗传多样性与遗传分化分析。获得该物种cyt b基因全序列1 141 bp,其中保守位点1 072个,变异位点69个,无插入和缺失位点。96只个体具有5个单倍型,群体单倍型多样性为0.359±0.059,核苷酸多样性为0.021±0.010,表现为低单倍型多样性与高核苷酸多样性的群体遗传特征。以外群子陵吻虾虎R.giurinus、褐吻虾虎R.brunneus和短吻红斑吻虾虎R.rubromaculatus构建的分子系统发育树和网络分支图显示,波氏吻虾虎群体的所有单倍型与外群物种分开,构成一个单系群,并分化为2个明显的系统分支。分子变异分析结果表明,种群间和种群内的遗传变异率分别为62.99%、37.01%,固定指数为0.630(P<0.01),证实波氏吻虾虎群体形成了显著的遗传分化结构。波氏吻虾虎在珠江源头入侵地具有较高的遗传多样性水平与显著的遗传结构,入侵种群可能受到了奠基者事件和遗传瓶颈效应的影响,而多次人为引入和水利大坝的隔离作用可能为该物种扩散分布和积累突变提供了条件。研究结果将为防治波氏吻虾虎的入侵危害及保护土著鱼类物种多样性提供科学指导。     

Genetic and morphological studies of Nothobranchius (Cyprinodontiformes) from Malawi with description of Nothobranchius wattersi sp. nov.

Molecular and morphological data were used to explore evolutionary differentiation among populations of Nothobranchius in the Lake Malawi–upper Shire River and the Lakes Chilwa–Chiuta drainage systems in Malawi. The aim of the study was to test the hypothesis that Nothobranchius of the Malawi–Shire system constitute a separate evolutionary group from Nothobranchius kirki. Mitochondrial and nuclear sequence data show a strongly supported phylogenetic split into two monophyletic groups separating the Lake Malawi basin fish from N. kirki. Unlike N. kirki, Lake Malawi–Shire fish do not deviate from neutrality and express an excess of rare haplotypes and mutations in terminal branches, characteristic of recently expanded populations. Further, the two groups significantly differ in morphology. Two body characters (dorsal‐fin base length and pre‐pelvic–pre‐anal distance) are significantly different between the two species in both sexes. Several other characters are significantly different in either male or female comparisons with respect to both standard and head lengths, and robust morphological differentiation is detected by multivariate analysis. The two groups are readily distinguished on the basis of male colouration, especially in scale centres and the caudal fin. On the basis of this differentiation at the molecular and morphological levels, in addition to colouration, the Lake Malawi–Shire fish are hereby formally recognized as constituting a new species, Nothobranchius wattersi. This distinction is in agreement with the geomorphologic and recent climatic history in the region.     

Gobies of the genus <Emphasis Type="Italic">Rhinogobius</Emphasis> (Gobiidae) of primorye and water bodies of Central Asia and Kazakhstan: II. Comparative craniological analysis of gobies introduced to Central Asia

The craniological analysis of the gobies introduced from China to Central Asia and identified previously as Rhinogobius cheni based on the sample from the Akkurgan fish farm (basin of the Chirchik River) and the sample from the Saryyazyn water reservoir (basin of the Murgab River) is given. The morphological characteristics of the studied gobies are discussed in connection with the data on the skull structure of the other species of the suborder Gobioidei. It is shown that the level of divergence by the craniological indices between two naturalized populations of the Chinese goby is higher than that between the local populations of the studied species of the European gobies and their populations from the basins of different seas, that can be explained on the basis of the founder principle proceeding from the start states of divergence deviating from the parameters modal for the species.