中国水域江豚颅后骨骼的生理变异

本文根据１４２号各年龄段的江豚颅后骨颅标本（其中长江种群标本３８号,黄海种群标本５９号,南海种群标本４５号）,选用４２项颅后骨骼变量,应用ｔ－检验、协方差分析和析研究了颅后骨骼在各地理种群之间的变异。结果表明,（１）中国水域江豚不同种群之间在颅后骨骼上的差异是明显的,而且表现在包括初生幼体在内的所有的年龄段的标本中。（２）南海种群的颅后骨骼最发达。长江种群次之,黄海种群的最不发达。（３）黄海种群与     

中国水域江豚颅骨的地理变异

本文根据１４４号江豚骨骼标本（其中长江种群标本４０号,黄海种群标本５９号,南海种群标本４５号）,选用４２项颅骨测量变量,研究了颅骨在各地理种群之间的差异。ｔ－检验和协方差分析表明：长江江豚成体的颅基长比较小。南海种群吻长小于其它两个种群,而吻宽则最大,长江种群次之,黄海种群最小。黄海种群的前颌骨宽、颧宽、眶前突最大宽和眶后突最大宽比其它两个种群的小。黄海种群的上颌齿较多,而南海种群则下颌齿较多,长     

江豚生命表和种群动态的研究

根据江豚长江种群、黄海种群和南海种群的年龄鉴定数据,编制了３个种群的静态生命表,绘制了各种群的存活曲线、死亡曲线和死亡率曲线,计算了各种群的内禀增长能力。３个种群的存活曲线均为Ｃ型（Ｏｄｕｍ,１９８３）,但南海种群和黄海种群的陡度更大。各种群的０～２龄,以及黄海江豚和南海江豚的２～４龄是死亡高峰期。死亡率曲线在各种群中呈现一定的波动。各种群的性比与１∶１没有显著性差异。３个种群的Ｒ０和λ均小于１,ｒｍ均小于０,表明它们的数量有减少的趋势,需加强对它们的保护。     

中国近海的两种宽吻海豚

本文研究了采自黄海和东海的23件宽吻海豚标本及采自南海的10件南宽吻海豚标本。宽吻海豚体腹面灰白色,成体最小的全长大于2.5米,颅基长495-580毫米。南宽吻海豚体腹面具纵长形暗色点斑,成体最大的全长小于2.5米,颅基长455-497毫米。两者的颅骨和颅后骨胳各有一些差别。中国南海标本的形态性状与南非海域及巴基斯坦沿岸的宽吻海豚相似。黄海和东海标本与东太平洋的标本有一些差别,而与南非及不列颠海域的宽吻海豚标本相似。     

江豚眼的解剖学和组织学研究

统计结果表明:与黄海沿岸种群江豚相比,长江种群江豚眼中央至吻端的平均距离显著较小,与长江弱光环境相适应。长江种群平均眼裂高比较小,眼球平均相对水半径比较短,而前后径比较长。眼球较趋近于圆球型。视觉较近视。在显徽与亚显微结构方面未发现两种群之间有差异。江豚无典型的视锥,而具有细胞核和内节呈视锥状、外节呈视杆状的一种中间型视细胞。     

中国水域江豚种群遗传变异的研究

运用ＰＣＲ产物的银染测序技术,测定了中国水域江豚长江豚长江种群、黄海种群和南海种群共１２头个休的２个长度分别为３１７ｂｐ和２４５ｂｐ的ｍｔＤＮＡ控制区序列,并以此分析了江豚种遗传变异。结果表明：中国水域江豚各种群的控制区序列所定义的单倍型互不相同,无共有的单保型。以２个ｍｔＤＮＡ控制区片段的核苷酸序旬,以及把２个片段合并后产生的较大片段的序列,用ＭＥＧＡ软件中的ＵＰＧＭＡ法构建的系统树把江豚聚类为     

江豚的年龄鉴定、生长和生殖的研究

本文根据在长江中下游,长江口和中国东北沿海收到的68头江豚标本,对江豚年龄鉴定的方法作了摸索和研究。从年龄,生长和生殖的角度系统分析了江豚的一些种群生物学特征。江豚年龄与生长的关系在一定范围内遵循的幂函数型式。4-5龄以前,江豚的生长迅速,此后减慢。江豚首次性成熟年龄雌性4龄,雄性4.5龄。性成熟时体长雌性133cm,雄性140cm。根据16头胎儿资料,用对数分割法反推出江豚的交配期较长,并有两个可能的交配高峰,分娩的高峰为2-4月。断奶年龄约为0.5龄。粗略估算长江江豚的年生殖率为20％。长江的江豚和中国沿海的江豚在形态和种群结构上各具特点。从江豚的年龄组成看出,幼龄组(0-4龄)的比例较大,结构基本正常。       

江豚小肾及肾小球的测量和计数研究

作者做了江豚的小肾和肾小球的测量和计数,首次报道了肾小球总数及体积。长江标本和黄海沿岸标本的小肾数量和直径,肾小球数量和体积都没有显著差异,说明其小肾化程度和肾小球数目与环境盐度不直接相关。江豚的肾小球数量和体积都比体重与之相近的陆生兽类大得多。鲸类由于水生生活,新陈代谢较高,因而其肾的小肾化可能与排泄量大有关系。     

江西水域枯水期长江江豚种群数量和分布特征

研究于2021年11—12月,设置12条考察路线,采用同步目视考察法,对包含长江干流江西段、鄱阳湖和赣江下游的江西水域长江江豚数量和分布开展了考察,结合历史资料,探讨了该水域长江江豚种群数量和分布规律及江湖迁徙关系。结果显示, 11月考察观测到长江江豚217群次、454头次, 12月考察观测到长江江豚236群次、569头次,受水位和天气等环境条件影响,两次考查观察到的长江江豚数量差异显著(t=–2.23, P<0.05)。11月和12月江豚分布规律基本一致:长江江西段,江豚主要分布在湖口石钟山-彭泽三号洲水域;鄱阳湖适宜水深范围水域都有长江江豚分布,其中吴城望湖亭-渚溪河口、都昌船厂-黄金咀-三山-瓢山水域是江豚高密度分布区;赣江下游,长江江豚分布在扬子洲渔业村附近水域。两次考察目击率分别为1.00和1.08次/km,均高于往年调查结果,由此推测,鄱阳湖长江江豚种群数量可能有所增长。鄱阳湖通江水道蛤蟆石-石钟山水域,两次考察分别仅发现3头和2头长江江豚,推测调查期间长江江豚在长江干流和鄱阳湖之间的迁移行为较少,未来需进一步管控江湖迁移水域的人类活动,促进江湖迁移。吴城望湖亭-渚溪...     

江豚的外形和骨骼

江豚Neomeris phocaenoides(Cuvier)是我国沿海及长江中下游常见的小型齿鲸,属于海豚科Delphinidae。秉志(1925)曾记述过本种一例骨骼,Howell(1927)记述过数例骨骼,寿振黄(1938)也记述过一例颅骨。我们采用了新鲜标本16例(包括一例胎儿),并制成完整骨骼5例,头骨5例(包括一例分散头骨和一例胎儿头骨),进行了较系统的观察。一例胎儿比较少见,对胎儿骨骼的观察有助于了解骨骼的分界、头骨的演变和个体发生过程中某些结构的退化或加强现象。     

Mitochondrial control region variability of baiji and the Yangtze finless porpoises,two sympatric small cetaceans in the Yangtze river

BaijiLipotes vexillifer (Miller, 1918) and the Yangtze finless porpoiseNeophocaena phocaenoides asiaeorientalis (Pilleri and Gihr, 1972) are two sympatric small cetaceans inhabiting the middle and lower reaches of the Yangtze River. In this study, a fragment (420–428 bp) of the mitochondrial control region was sequenced to provide the first comparative survey of genetic variability and population structure in these two endangered species, with samples of finless porpoises from the Yellow/Bohai Sea, East China Sea, and South China Sea also included. Low values of haplotype diversity and nucleotide diversity were found for both species, especially for the baiji and the Yangtze River and South China Sea populations of finless porpoises. The analysis of molecular variance (AMOVA) supported a high level of overall genetic structure among three porpoise populations in Chinese waters, with greatest differences found between either the Yangtze River population or the Yellow Sea population and the South China Sea population. The differentiation between the Yangtze and Yellow Sea populations was not significant, and the males have higher genetic differentiation than the females, suggesting a significant female-biased dispersal between these two populations. This study showed that the Yangtze finless porpoise, unlike the sympatric baiji, was not a genetically isolated population. The Yangtze and Yellow Sea porpoises should be included in the same management unit, but further studies using more samples and especially based on more molecular markers are urgently needed to confirm this.     

POPULATION GENETIC STRUCTURE OF FINLESS PORPOISES, NEOPHOCAENA PHOCAENOIDES, IN CHINESE WATERS, INFERRED FROM MITOCHONDRIAL CONTROL REGION SEQUENCES

Seven hundred and twenty base pairs (bp) of the mitochondrial control region from 73 finless porpoises, Neophocaena phocaenoides , in Chinese waters were sequenced. Thirteen variable sites were determined and 17 haplotypes were defined. Of these, 5 and 7 were found only in the Yellow Sea population and the South China Sea population, respectively, whereas no specific haplo-type was found in the Yangtze River population. Phylogenetic analyses using NJ and ML algorithm did not divide the haplotypes into monophyletic clades representing recognized geographic populations of finless porpoises in Chinese waters, suggesting the existence of migration and gene flow among populations. Analysis of molecular variance showed the obvious population genetic structure (φ_st= 0.41, P < 0.05); however, the structure was mainly between either the Yangtze River population or the Yellow Sea population and the South China Sea population. The genetic diversity (nucleotide diversity and haplotypic diversity) of the Yellow Sea population was significantly higher than those of the Yangtze River population and the South China Sea population, suggesting the relatively later divergence of the latter two populations and supporting the Yellow Sea population as the original center of Neophocaena .     

Sequence Polymorphism and Geographical Variation at a Positively Selected MHC-DRB Gene in the Finless Porpoise (Neophocaena phocaenoides): Implication for Recent Differentiation of the Yangtze Finless Porpoise?

Sequence polymorphism at the MHC class II DRB locus was investigated in three finless porpoise (Neophocaena phocaenoides) populations in Chinese waters. Intragenic recombination and strong positive selection were the main forces in generating sequence diversity in the DRB gene. MHC sequence diversity changed significantly along the study period. Significant decrease in heterozygosity and lost alleles have been detected in the Yangtze River population and South China Sea population since 1990. Furthermore, there is a trend of increasing population differentiation over time. Especially, the genetic differentiation between the Yangtze River population and the Yellow Sea population was very low prior to 1990 (F _ST = 0.036, P = 0.009), but became very significant after 1990 (F _ST = 0.134, P < 0.001), suggesting a recent augmentation of genetic differentiation between both populations probably in a relatively short-term period. Porpoises from the Yangtze River displayed divergent frequencies of shared and private alleles from those displayed by two marine populations, which suggest that the former riverine population has been under a different selection regime (characteristic of a fresh water environment) than that of its marine counterparts.     

长江江豚繁殖生物学研究概述

长江江豚,即江豚扬子亚种,是仅分布于长江及附属湖泊中的唯一江豚淡水亚种,也是3个江豚亚种中最濒危的一个亚种。本文概述了30 年来国内外关于长江江豚繁殖生物学方面的研究成果,主要从繁殖生态学、组织解剖学、生理学以及行为学等4 个方面阐述了长江江豚繁殖生物学研究现状,并对其中一些相互矛盾和有争议的问题进行了分析。探讨了今后研究中应注意的重点问题,力图为长江江豚的繁殖生物学研究指明方向,为早日实现长江江豚的人工繁殖奠定基础。
     

Genetic Variation Analysis of Mugil cephalus in China Sea Based on Mitochondrial COI Gene Sequences

In this study, genetic diversity and population genetic structure of flathead grey mullet, Mugil cephalus, among four China Sea populations were investigated by COI sequences. All the populations studied had high values of haplotype and nucleotide diversity, except for the Yellow Sea population. In the phylogenetic tree, these haplotypes clustered in two groups, one for the populations from the Bohai and East China seas, and the other from the Yellow and South China seas. Analysis of molecular variance indicated that the northern populations (Bohai and East China) had lower genetic divergence (0.0725, P > 0.05) than that of the southern population (South China) (0.4530-0.6827, P < 0.001), suggesting that two distinct genetic groups exist in Chinese waters. Tests of neutral evolution and mismatch distribution indicated that no historical demographic expansion occurred in these populations. The results provide new information for genetic assessment, fishery management, and conservation of this species.     

中国近海银鲳线粒体COⅠ基因序列变异分析

对采自黄海、东海和南海的7个银鲳群体的线粒体COⅠ基因序列变异进行分析,研究银鲳的遗传多样性、遗传结构和群体历史动态。在所分析的111个个体中检测到16个单倍型。7个群体呈现出高的单倍型多样性（h=0.564～0.688） 和低的核苷酸多样性（π=0.001～0.003）。单倍型遗传学关系、两两群体间的F_ST值和分子方差分析均表明中国近海7个银鲳群体间的遗传分化不显著。中性检验和核苷酸不配对分析均表明中国近海银鲳经历了晚更新世的群体扩张事件,扩张时间约为6.0×10⁴～1.04×10⁵ 年前。研究结果表明,银鲳的卵和幼体具有较强的扩散能力、中国近海的海洋环流以及近期的群体扩张可能是造成中国近海银鲳群体在线粒体COⅠ基因序列上存在较高的遗传同质性的原因。     

Lack of genetic structure in endangered large yellow croaker Larimichthys crocea from China inferred from mitochondrial control region sequence data

The large yellow croaker Larimichthys crocea is an important commercial marine fish species in China. However, information about the population structure of this species is limited. In the present study, mitochondrial DNA (mtDNA) control region was sequenced from four populations of the yellow croaker in the southern Yellow Sea, East China Sea and South China Sea to investigate the genetic structure of this species. A total of 54 haplotypes were detected among 62 individuals of large yellow croaker. High levels of population genetic diversity were observed. Among the four populations, the haplotype diversity was between 0.9895 ± 0.0193 (Xiamen) and 1.0000 ± 0.0524 (Lvsi, Zhoushan). The nucleotide diversity ranged from 0.0208 ± 0.0108 (Xuwen) to 0.0246 ± 0.0138 (Lvsi). The results of AMOVA detected no significant differences among populations. The conventional F_ST statistics were negative and insignificant values. These indicated lack of population genetic structure throughout the Yellow Sea, East China Sea and South China Sea, and random mixing of individuals among the samples. Biological characters of large yellow croaker and lack of physical barrier in the studied area could be the reasons for lack of genetic structure in this species.     

Development of tetranucleotide microsatellite loci for the finless porpoise (<Emphasis Type="Italic">Neophocaena phocaenoides</Emphasis>)

The finless porpoise, Neophocaena phocaenoides, is endemic to the coastal waters of the Indo-Pacific, ranging from the Persian Gulf to Japan. Nine tetranucleotide microsatellite loci were isolated from the finless porpoise (Neophocaena phocaenoides). Polymorphism of each locus was assessed in 39 unrelated individuals from the Yellow Sea and the South China Sea of the Chinese waters. The number of alleles per locus varied from 2 to 11. The ranges of observed and expected heterozygosity were 0.154–0.795 and 0.146–0.839, respectively. Cross-species amplification of these loci was tested in other cetacean species. These microsatellite markers described here will be suitable for population genetic studies of finless porpoises and other cetacean species.     

江豚的小肾结构指数和尿浓缩能力

对江豚的六项小肾结构指数的测定发现,黄海沿岸江豚的小肾结构指数明显高于长江江豚的。提示前者具有较高的尿浓缩能力。对尿的分析所获结论相同,反映出二者对所栖水域的不同渗透浓度的适应。