基于椭圆傅里叶分析的次南极电灯鱼矢耳石形态多样性

次南极电灯鱼矢耳石形态特征具有多样性.为了深入研究其形态特征,利用南设得兰群岛外侧水域采集的456尾次南极电灯鱼(体长范围6.0～8.8 cm)样本,对其矢耳石形态进行分析和判别.根据形态特征将次南极电灯鱼耳石分为4种类型,并采用椭圆傅里叶分析法选取表征耳石类型的77个傅里叶特征系数进行了分析.结果表明: 对4种耳石类型两两比较后发现,具有显著性差异的傅里叶特征系数最多及最少分别占总体的61%和28.6%;对77个傅里叶系数进行主成分分析,前22个主成分解释了总变异的76.6%;选取了17个傅里叶特征系数进行判别分析,建立判别函数,总体判别率为87.2%;根据椭圆傅里叶分析重建的耳石轮廓反映了4种耳石类型间的差异.4种耳石类型在不同体长及体质量的次南极电灯鱼中皆有出现,表明耳石类型具有随机性,且左右耳石类型不一致,表明其左右耳石外形具有差异性.4种耳石类型中,Ⅰ型和Ⅱ型占总体的72.6%,为次南极电灯鱼耳石的主要形态;Ⅲ型和Ⅳ型占总体的27.4%,为次要形态.     

南极鱼类耳石微化学研究进展

南大洋生态系统的特异性极为显著,栖息在该海域的鱼类资源也存在着较为明显的本地特征以及对极端环境的适应能力。耳石微化学记录了鱼类完整生活史过程,可以揭示鱼类生活史过程中经历的时空变化。利用耳石中微化学元素,可以解决鱼类生态学中,如产卵场和洄游路径推测、生活史过程重建、种群划分等一系列实际问题。随着耳石微化学技术的不断完善,耳石微化学研究在海洋鱼类中的应用越来越广泛。相对于其他海区,目前南大洋鱼类耳石微量元素研究相对较少,仅涉及3科11种鱼类,约占南极鱼类总数的5%,且主要研究集中于商业性价值较高的鱼类,包括小鳞犬牙南极鱼(Dissostichus eleginoides)、鳞头犬齿南极鱼(D.mawsoni)、次南极电灯鱼(Electrona carlsbergi)、南极电灯鱼(E.antarctica)、裘氏鳄头冰鱼(Champsocephalus gunnari)和侧纹南极鱼(Pleuragramma antarcticum)等11种南极鱼类。耳石微化学研究主要集中在鱼类栖息环境重塑、种群划分以及生活史过程重建等三个方面。今后,更为先进的技术,如微计算断层扫描技术以及人工智能等,将为南极鱼类耳石微化学研究提供重要的支撑。考虑到南大洋鱼类多数具有典型的环南极分布特征,可通过耳石微化学技术进一步探究鱼类产卵场推定以及环极连通性等,并进一步阐释南极鱼类的生物-环境相互作用,相关工作也将为南大洋鱼类资源的开发利用及有效管理提供支撑信息。     

西沙群岛鹦嘴鱼科耳石形态学物种鉴定的可行性研究

研究于2018—2021年在西沙群岛海域采集鹦嘴鱼样本,通过传统形态测量法选取的19个耳石形态指标和椭圆傅里叶分析法选取的77个椭圆傅里叶系数对其进行鉴别分析,探究耳石形态在鹦嘴鱼科物种鉴别中的可行性。结果表明,仅使用耳石形态指标鉴别鹦嘴鱼时综合判别率为56.8%,低于仅使用椭圆傅里叶系数的63.1%和两种参数结合的75.7%;而结合两种参数对其4个属的综合判别率为88.6%,其中绚鹦嘴鱼属的判别率达到100%; 15种鹦嘴鱼的耳石形态聚类结果与已有研究的进化树结果基本一致,特别是属层面的聚类,呈现高度一致,证实了耳石形态具有遗传的属性,也说明了耳石形态学用于鱼类物种鉴定的可行性。研究结果将为西沙群岛鹦嘴鱼的基础研究提供科学资料,为鹦嘴鱼资源的保护与开发提供理论依据。     

六种鲤科鱼类耳石形态以及在种类和群体识别中的应用

描述了6种鲤科鱼类的耳石形态特征,并利用耳石形态的测量性状,对其种类特征进行了判别分析。其中,对张氏(卜夕又鱼)、长鳍吻鮈、圆口铜鱼、宜昌鳅（鱼它）和鲫的判别正确率为100％,异鳔鳅（鱼它）的判别正确率为90.91％,6种鱼类的平均判别正确率达到了99.1％,说明了鱼类的耳石形态特征可以用于鉴别种类。三个区域鲫群体的平均判别正确率为68.9％,显示三个区域鲫群体的耳石形态存在一定的差别。     

基于耳石形态的鱚属鱼类鉴别

利用9个耳石形状指标对我国鱚属鱼类少鳞鱚、多鳞鱚及斑鱚共78个个体的矢耳石形态进行了多元统计分析,同时对3个群体的74个少鳞鱚矢耳石形态进行了判别分析。单因子方差分析结果显示,少鳞鱚与多鳞鱚矢耳石的9个形状指标均存在显著差异(P<0.05);反映耳石长、短轴差异程度的第1主成分与反映耳石三维特征的第2主成分解释了85.943%的形态差异;9个指标在种间判别分析中的综合判别正确率为93.6%,种内判别分析中的综合判别正确率为93.2%。研究表明形状指标法可以作为中国鱚属鱼类鉴别的有效手段。     

鲬鱼耳石形态多样性研究

硬骨鱼类的矢耳石在物种间存在明显的形态差异, 常常被用来进行鱼类的分类研究13。例如, 张国华等通过形态的观察与描述对鲤科鱼类的耳石进行了区分4; 潘晓哲等采用耳石形状指数方法对 属鱼类进行了鉴别5; 王英俊用傅里叶方法研究了多种鱼类耳石, 并记录了它们之间的形态差异6。因为耳石坚硬不易被消化, 所以在水生动物的食性研究中, 利用耳石进行胃含物内种类鉴定可大大提高工作效率与准确性。此类研究也并不鲜见, 如张波等对黄海重要饵料鱼类的耳石形态做了较为详细的描述7, Fitch, et al.依据鲸类胃含物中的鱼类耳石形态鉴定了捕食鱼类的种类进而对其食性进行了研究8。另外, 不同生活环境能够导致耳石生长和形态的差异, 这也使其成为了群体差异研究的有效手段912。       

基于矢耳石形态特征的中国鲚属鱼类种类识别

分析了中国鲚属鱼类七丝鲚、凤鲚、刀鲚和短颌鲚共4种205尾2龄鱼矢耳石的32个形态特征。对9个可量性状的主成分分析表明,反映矢耳石体积和基叶大小的第1主成分,以及与反映翼叶大小的第2主成分共同解释了总变异的91.2%,是种类判别的主要依据。对10个比例性状的逐步判别显示,4个种的平均正判率达95.6%,但交互验证结果却显示,刀鲚与短颌鲚间存在着20.1%的误判率,表现出与传统的依据外部形态分类和线粒体DNA控制区全序列分析的相似结果。这表明,短颌鲚并非有效种,而是刀鲚的淡水生态型种群,也预示着耳石形态分析在近缘种判别方面的良好应用前景。     

西南大西洋拉式南美南极鱼耳石外型特征

基于2009年12月至2010年1月西南大西洋阿根廷外公海海域采集的拉式南美南极鱼(Patagonotothen ramsayi)145对耳石样本,对其形态特征进行了分析。结果表明,拉式南美南极鱼耳石长(OL)和宽(OW)分别为4.50—7.99 mm和1.99—3.69 mm之间。耳石外型呈狭长有缺刻,基叶长,翼叶短,具明显的主间沟,后端闭合呈钝圆形,整体结构凸凹不平。左右矢耳石形态无显著性差异。耳石绝对尺寸随体长增加而增加,但相对尺寸减少,耳石的形态结构比例基本不变。耳石长、宽、面积(S)及周长(P)与体重呈对数关系,耳石背长(DL)和基叶长(RL)与体重(W)呈指数关系,耳石背宽(DW)与体重呈乘幂关系,而耳石翼叶长(ARL)与体重则呈线性关系。耳石宽、面积、背长、背宽、周长、翼叶长及基叶长与体长(L)拟合符合对数关系,仅耳石长与体长呈线性关系。本研究可为鱼类耳石形态研究提供参考,并为南美南极鱼渔业生物学研究提供基础资料。     

耳石微化学在海洋鱼类洄游类型和种群识别研究中的应用

水环境中化学元素会有规律性地在鱼类耳石上沉积。耳石可作为生境"指纹"标签的独特属性使其更能有效地应用于鱼类资源时空动态的研究。现针对了解较少的海洋鱼类耳石微化学所涉及的主要元素,综述了Sr:Ca值和多元素组合在这些鱼类生活史重建、迁移模式反演和资源种群识别上的研究进展。进展显示,海水中Sr:Ca值的微小变化可以通过在海洋鱼类耳石中的元素积累而放大,有助于把握鱼类的种间差异或种内不同发育阶段个体的差异。耳石中多元素组合的分析,亦可有效解释海洋鱼类生活史不同阶段间的生境转换和洄游特征,甚至"破译"复杂的资源种群结构。耳石微化学在海洋鱼类养护研究上具有极大的潜力,相关研究需要在我国得到更多的重视和更大的支持。     

中国鲚属鱼类的矢耳石形态特征

分析了205尾分布于中国的4种2龄鲚属鱼类的矢耳石形态特征。结果显示,这4种鱼类的矢耳石都具有翼叶和基叶,但无后基叶和副基叶,中央突也不明显。背侧有脊突,叶形晶状突呈小三角形,仅限于腹侧。主凹槽明显,直管状,后端封闭。4种鱼矢耳石长轴长为体长的1.68%~2.82%,矢耳石重为体重的0.26‰~1.71‰;不论绝对重量或面积,均以七丝鲚和凤鲚的最大,刀鲚的次之,短颌鲚的最小,显现出与在海水中生活的时间呈正相关性。刀鲚和短颌鲚的矢耳石较轻薄,单位面积均重1.22~1.40mg/mm2;七丝鲚和凤鲚的较厚重,单位面积均重约1.86mg/mm2。矢耳石的长轴、短轴和单位重量等的变异系数,均要小于其体长特别是体重的变异系数,矢耳石形态的稳定性显著优于其身体形态的稳定性。     

Sex-linked variations in the sagittal otolith biometry of Nemipterus randalli (Russell, 1986) from the eastern Mediterranean Sea

Few studies have been conducted on the sagittal otolith shape and morphometry of Nemipterus randalli, and none of these studies has examined the effect of sexual dimorphism on the otolith morphology of this species, therefore this study aimed to contribute to knowledge about the otolith morphology of N. randalli, an invasive fish species for the Mediterranean Sea. For this purpose, a total of 132 samples (51 female and 81 male) were obtained from İskenderun Bay with the help of commercial fishermen in November 2018. Relationships between otolith measurements and fish size were determined. Shape indices and elliptic Fourier coefficients were calculated. Significant differences were detected between males and females in all analysis. The sexes were separated from each other using both shape indices and elliptic Fourier coefficients. However, shape analysis was more effective in distinguishing sexes than traditional morphometric analysis. Asymmetry in the otolith morphology of sexes has been attributed to differences in the growth and sexual maturity of male and female fish. The results of this study indicated that sexual dimorphism in Nemipterus randalli was also reflected in the otolith morphology.     

Migration of Sakhalin taimen (<Emphasis Type="Italic">Parahucho perryi</Emphasis>): evidence of freshwater resident life history types

Sakhalin taimen (Parahucho perryi) range from the Russian Far East mainland along the Sea of Japan coast, and Sakhalin, Kuril, and Hokkaido Islands and are considered to primarily be an anadromous species. We used otolith strontium-to-calcium ratios (Sr/Ca) to determine the chronology of migration between freshwater and saltwater and identify migratory contingents of taimen collected from the Koppi River, Russia. In addition, we examined taimen from the Sarufutsu River, Japan and Tumnin River, Russia that were captured in marine waters. Transects of otolith Sr/Ca for the Sarufutsu River fish were consistent with patterns observed in anadromous salmonids. Two fish from the Tumnin River appeared to be recent migrants to saltwater and one fish was characterized by an otolith Sr/Ca transect consistent with marine migration. Using these transects as benchmarks, all Koppi River taimen were classified as freshwater residents. These findings suggest more work is needed to assess life history variability among locations and the role of freshwater productivity in controlling migratory behavior in taimen.     

基于耳石元素微化学的江苏吕泗近岸小黄鱼生境履历重建

利用电子显微探针元素分析技术,对江苏吕泗近岸海域小黄鱼矢耳石的Sr和Ca微化学特征进行了研究.结果表明: Sr含量在小黄鱼耳石的矢状面上呈非均匀分布,总体为核心部位高,其余部分明显降低.核心高Sr区域的Sr/Ca比值为(7.10±1.00),其余部分为(4.79±1.01),两者差异极显著.后者部分个体存在Sr含量更低的区域,Sr/Ca比值为(3.51±0.76).基于这些结果重建了吕泗近岸小黄鱼的生境履历： 它们在孵化及初期发育阶段生活在高盐度生境,随后的生长和发育过程则会洄游至盐度稍低的生境;部分个体的早期发育阶段还会选择利用更低盐度的生境.     

Diversity of life strategies of pikepech <Emphasis Type="Italic">Sander lucioperca</Emphasis> (L.) in the Lower Volga (by the data of microelement composition of otolithes)

Strontium (Sr) and calcium (Ca) contents and Sr/Ca ratios in otoliths of pikeperch Sander lucioperca have been studied by X-ray fluorescent microanalysis. A sample of 95 specimens from the Lower Volga region are studied. The fish were obtained in a section of the Akhtuba River at a distance of 250–279 km upstream from the Caspian Sea. Some specimens in the sample have low strontium content throughout the otolith. The other fish have increased both Sr content and Sr/Ca ratios in core zones of otolith or near its outer edge: the Sr/Ca ratio is over 6.00 × 10^–3, with a maximum at 10.02 × 10^–3. The fish with a low Sr/Ca ratio live in freshwater and demonstrate a resident life history strategy. Pikeperch that have increased ratios of Sr/Ca in outer zones of otolith demonstrate a migratory life history strategy. These fish leave the freshwater of the Volga and feed in brackish water of the Northern Caspian Sea. Some migratory fish migrate to the sea as underyearlings, stay in a brackish water for 1 year or less, and then return back to fresh water for the rest of its life. The other group migrates back and forth from freshwater to the sea several times during their life. Finally, some fish leave freshwater for 1–2 years, spending this time in the Northern Caspian Sea. The conclusion is that the pikeperch stock in the Lower Volga has a complicated composition and consists of freshwater (residents and rheodromic ones) and migratory (anadromous and semianadromous) fish.     

Histopathology and cellular response in Enteromyxum leei (Myxozoa) infections of Diplodus puntazzo (Teleostei)

Enteromyxum leei is an intestinal parasite responsible for serious outbreaks in Mediterranean sharpsnout sea bream Diplodus puntazzo. E. leei infection was experimentally transmitted to healthy D. puntazzo (R) by cohabitation with infected donor fish. Haematological changes and histopathological damage were evaluated in relation to the course of infection. The prevalence of infection in R fish was 100% from day 10 post-exposure (p.e.) onwards, and the infection intensity and histopathological damage increased progressively. Different developmental stages were found in the infected intestines, including proliferative (stages 1–3) and sporogonic (stages 4 and 5) stages. Intestinal damage consisted of vacuolation, necrosis, detachment and sloughing of epithelium, and was correlated with the progression of the infection and with the development of the parasite. Sporogonic stages appeared from day 20 p.e. onwards. Initially, D. puntazzo seems to counteract the infection through the increase in leucocyte numbers, respiratory burst activity, haematopoietic activity and MMC. Two types of eosinophilic granular cells (EGC1 and EGC2) were detected in the intestinal epithelium and lamina propria. EGC1 numbers decreased with the progression of infection, whereas an increase in EGC2 occurred, mainly in the lamina propria. The involvement of the cellular immunity in the response of D. puntazzo to E. leei was demonstrated. The depletion of this response at a certain point of the infection could contribute to the high virulence of this myxozoan in this fish species.     

Otolith Shape Analysis as a Tool for Species Identification and Studying the Population Structure of Different Fish Species

An analysis and a comparison of the methods of geometric morphometrics as applied to fish species identification and to studies on the population structure of fish stocks based on peculiarities of the otolith shape are performed. A review of the geometric morphometric methods used in studies on fish otoliths is provided. The results of our own research on possible utilization of elliptical Fourier analysis for species identification are also described.     

东太平洋公海茎柔鱼饵料中鱼类和头足类组成初步分析

茎柔鱼(Dosidicus gigas)广泛分布于东太平洋海域,在海洋生态系统中扮演着重要角色。本研究根据2019年6—12月我国鱿钓生产船在东太平洋公海采集的62尾茎柔鱼样本,对其胃含物残留的4131个耳石和75个角质颚样本进行鉴定分析。结果表明: 茎柔鱼主要摄食鱼类10种、头足类4种。从摄食饵料的出现频率和数量百分比来看,主要摄食的鱼类饵料为荧串光鱼、朗明灯鱼和墨西哥尾灯鱼,荧串光鱼在不同胴长组的茎柔鱼胃内均有出现,是茎柔鱼最重要的饵料;摄食的头足类主要有茎柔鱼、鸢乌贼和爪乌贼。随着胴长的增大,茎柔鱼摄食的饵料种类不断增加,头足类和灯笼鱼饵料比例增加,且摄食的饵料尺寸增大,摄食营养结构发生改变,摄食营养水平随之提高。研究结果可为评估不同饵料生物在茎柔鱼食性转变过程中的食物贡献提供基础资料。     

A first attempt at determining larval growth in three Antarctic fish from otoliths and RNA/DNA ratios

Otolith growth and RNA/DNA ratios of larval stages of Notolepis coatsi, Gobionotothen gibberifrons and Trematomus scotti, three Antarctic fish, were studied during early 1998. RNA/DNA ratios were significantly different between the notothenioids and paralepidids (P<0.01), but similar among notothenioids (P>0.05). The ratios were independent of larval total length and water temperature. Recent otolith growth (based on the last five increments) and biochemical indices correlated slightly, but not significantly. N. coatsi inhabited deeper and colder waters of the Weddell Sea and showed less growth than the other species, which are associated with the Antarctic Peninsula. In all three species, some larvae had very good growth rates though most were rather poor. Recent growth indices might allow the detection and back-dating of growth changes in Antarctic larvae, and provide insight into a crucial yet poorly understood life-phase of these fish.