头足类耳石信息分析的研究进展

耳石的轮纹结构与化学组成相当稳定,记录了个体生活过程中丰富的生物-物理-化学环境信息,是一种很好的信息载体.因此,通过耳石信息分析可以揭示头足类的生活史历程,掌握其生活史各阶段的生态环境特征,这不仅具有重要的理论意义,而且具有较为广阔的应用前景.文章依据近年来国内外有关头足类耳石信息分析的研究成果,综述了头足类耳石日轮及微量化学的研究现状,概括了耳石信息分析在渔业资源及环境科学等方面的应用,并对今后的研究工作提出了方向与内容上的展望.     

内壳在头足类年龄与生长研究中的应用进展

年龄与生长是渔业基础生物学研究的重要内容。体长频度法估算头足类的年龄并不可靠,而利用硬组织来研究头足类的年龄和生长是最为有效的方法之一。内壳作为头足类少数硬组织之一受到国内外学者的广泛关注。本文从内壳的提取、保存、制备、观察,生长纹的特征,生长纹周期性以及日龄鉴定等方面综述了其在头足类年龄和生长方面的研究进展。分析认为,柔鱼类内壳因其生长早期的生长纹不清晰而无法用来鉴定其整个生活史的年龄;乌贼类内壳因其生长受环境尤其水温的影响显著,因此并不适合用作年龄鉴定的材料;而章鱼类内壳在其年龄和生长研究中应用前景最广泛。今后的研究希望能够在年龄鉴定基础上,开展内壳时间序列上的微量元素与稳定同位素研究,为进一步分析头足类的种群结构、摄食生态、栖息环境以及生活史等内容提供基础资料。     

中国近海头足类基础生物学研究进展

本论文对中国近海头足类基础生物学的研究进展进行了回顾,重点对种类组成及地理分布、形态学测量及应用、年龄与生长、摄食生态学、发育与繁殖等方面进行了分析。分析认为,头足类组成与分布由北向南逐渐递增,渤海最少,南海最多。形态学测量及应用的研究主要集中在外形特征的描述及利用其进行种类鉴定,其它组织(如耳石和角质颚等硬组织)的研究较少,今后应该利用这些硬组织进行种类鉴别和种群划分。年龄鉴定作为头足类研究的重点之一,是生物学的基础内容,目前主要通过内壳和耳石对十腕目进行年龄与生长的研究。另外,耳石和角质颚等硬组织隐含着重要的生态信息,可利用其进行微量元素、稳定同位素与栖息环境的关系及其生活史过程等的研究。摄食生态主要用于了解头足类的生态地位,对于非养殖种类,主要研究其食物组成、摄食强度及营养级;而对于养殖种类,则可通过喂养研究其生长、成活率和孵化率等。因此,针对不同资源产业的发展阶段,中国近海头足类基础生物学的研究重点不一样,随着近海增殖放流等措施的发展,学者将注意力由头足类的自然群体转向养殖群体,更多的研究内容涉及胚胎发育、受精卵孵化、繁殖生物学、环境因子胁迫等方面。在今后的研究中,应利用乌贼类和蛸类作为实验材料,开展不同海洋环境条件下(包括海洋酸化等),头足类的生长与死亡、生活史等基础渔业生物学的研究,预测其可能产生的影响。综合分析认为,相对其它经济鱼类,近海头足类的基础生物学研究工作较为不足,应加强多学科的合作,系统、有计划地采集近海头足类样本,建立近海头足类的样本库和基础生物学库,为科学开发和利用近海头足类资源提供基础。     

头足类角质颚稳定同位素研究进展

角质颚作为头足类重要硬组织之一,结构稳定、耐腐蚀、易获取,蕴含着大量的生物与生态学信息,在头足类的年龄鉴定、生长估算、种群划分、摄食生态评估、洄游路线推测以及栖息环境重建等方面受到国内外学者的广泛关注。过去,角质颚的研究主要集中在形态与微结构的分析与应用领域。近年来,随着地球微化学手段的不断创新与进步,角质颚的稳定同位素的研究越来越受到海洋生物与生态学家的重视。本文根据国内外学者对其的研究成果,重点对碳氮稳定同位素在头足类摄食生态评估、栖息环境重建和洄游路线推测等方面的应用进行综述,旨在解读头足类不同生活史阶段的生物与生态信息,其应用前景十分广阔。     

温度和元素浓度对Sr在褐牙鲆仔稚鱼耳石中的沉积影响

科学认识鱼类耳石中微量元素沉积与主要水环境因子的关系是基于耳石微化学方法重新构建鱼类生活史及反演其环境履历的重要前提。本研究以环境与耳石中重要元素Sr为例，研究在不同水温(16℃、19℃和22℃)和不同元素浓度(1×、2×和3×Sr)下Sr在褐牙鲆(Paralichthys olivaceus)仔稚鱼耳石形成生长过程中(孵化后15~93 d)的沉积(Sr∶Ca比)特征。结果显示，在不同水温下，耳石中Sr∶Ca比随水体中Sr浓度的升高呈线性增长，而元素分配系数(DSr)随元素浓度的升高先降低然后趋于稳定。在不同Sr浓度下，耳石中Sr∶Ca比及DSr均随水温升高呈增长趋势，二者在22℃时的值均显著高于在其他水温时的值。耳石中Sr沉积能够表征褐牙鲆仔稚鱼所经历的水环境中Sr浓度和水温的变化，可作为元素指纹应用于褐牙鲆早期生活史的重建和环境履历的反演。     

中国南海南沙群岛海域鸢乌贼耳石微量元素组成特性

耳石是头足类重要的硬组织之一,存储了大量微化学信息,能够反映其栖息环境变化,是研究头足类生活史的重要材料。本文根据2017年3月—5月我国灯光罩网渔船于中国南海南沙群岛海域采集的1002尾鸢乌贼样本,利用激光剥蚀电感耦合等离子质谱法(LA-ICP-MS)分析了17枚鸢乌贼耳石微量元素的组成及分布。结果表明：南沙群岛海域的鸢乌贼耳石主要由56种微量元素组成,含量最多的前10种元素依次为钙(Ca)、锶(Sr)、钠(Na)、磷(P)、硅(Si)、钾(K)、镁(Mg)、铁(Fe)、钡(Ba)和硼(B)。方差分析表明,不同性别间Ca、Sr、Na、P、Si、K、Mg、Fe、Ba、B的分布均无显著性差异；不同孵化期的群体间Ca、Sr、Na、P、Si、K、Mg、Fe、Ba、B的分布也无显著性差异；不同耳石部位间Si、K、Fe无显著性差异,而Ca、Sr、Na、P、Mg、Ba、B则有显著性差异。     

基于耳石微化学分析的鱼类种群生态学研究进展

研究鱼类的种群生态学,破解其数量特征、生境利用、种群结构和动态变化等种群属性是保护和合理开发天然渔业资源的基础。耳石微化学分析是破解鱼类的种群生态学难题的新颖而有力的手段,不仅可以反演鱼类生活史过程中所经历的环境条件,还可溯源资源群起源的产卵场等关键生境,在鱼类资源种群空间结构形成机制研究及动态评估中具有优势。本文在分析耳石元素组成及其沉积特征的基础上,重点介绍了耳石微化学分析在鱼类种群生态学(如反演鱼类生活史、评估种群结构、把握关联性和破解混合群体的构成与来源等)中的应用进展,也客观评述了耳石微化学分析在鱼类种群生态学研究中的局限性与解决途径,并对今后相关技术的发展趋势及需要关注的科学问题进行了展望。     

头足类鞘亚纲繁殖力研究进展

头足类具有生长快、世代更替周期短、资源量丰富等特点,既是海洋生态系统中重要的生物种类,也是世界海洋渔业开发利用的重要捕捞对象。为深入掌握头足类的生活史特性,认知种群数量变动及其资源量补充过程,就头足类鞘亚纲种类繁殖力的研究现状进行了概括,包括繁殖力的定义及测定方法、头足类的繁殖力水平以及繁殖力变化特征等。结果显示,种间的繁殖力水平存在明显差异;繁殖力水平与亲体体型呈线性相关性,且与配子大小密切相关;栖息环境对头足类繁殖力特性有重要影响,繁殖力水平自低纬度向高纬度海域呈递减趋势,水温、初级生产力是重要的影响因素。深入认知头足类繁殖力特性,将有助于头足类资源的可持续开发利用及评估管理政策的制订。     

哥斯达黎加外海茎柔鱼耳石的微量元素

实验通过激光剥蚀电感等离子质谱法分析哥斯达黎加外海茎柔鱼耳石的微量元素,了解其微量元素组成及其与表温关系,推测其不同生活史阶段的栖息环境.结果表明,茎柔鱼耳石含有54种元素,其中Ca、Na和Sr为主要元素.总体耳石Sr/Ca大于太平洋褶柔鱼、巴塔哥尼亚枪乌贼和黵乌贼.胚胎期耳石Sr/Ca最高,随着年龄增加而下降.Sr/Ca与表温呈反比例关系.不同孵化月份的茎柔鱼在不同生长阶段的耳石Sr/Ca差异不明显.Ba/Ca可看做茎柔鱼垂直移动的指标元素,茎柔鱼仔鱼至成鱼期耳石Ba/Ca呈“U”型变化,与其幼体生活在海水表层,成体生活在较深层海水相对应.茎柔鱼耳石Mg/Ca核心高外围低,可能与耳石生长率逐渐减小有关,Mg/Ca与表温呈正相关.此外,研究认为茎柔鱼胚胎期是以自身携带的卵黄囊为营养物质,此时耳石的微量元素与亲体的遗传因素相关,与外界水环境无关.     

冬季厄尔尼诺发生期日本海太平洋褶柔鱼耳石外形的生长特征

耳石是研究头足类年龄与生长、种群结构和生活史的重要材料。根据2018年厄尔尼诺发生期冬季（12月）我国鱿钓船在西北太平洋日本海海域生产调查期间采集的530尾太平洋褶柔鱼(Todarodes pacificus)样本,首次对厄尔尼诺发生期太平洋褶柔鱼的耳石外形生长特征进行了报道。结果表明,日本海太平洋褶柔鱼的耳石具有宽大的背区、侧区和翼区,以及较狭长的吻区。主成分分析表明,耳石总长(TSL)、侧区长(LDL)、翼区长(WL)和最大宽度(MW)可以作为描述日本海太平洋褶柔鱼耳石外形生长特征的表征参数。协方差分析表明,耳石各外形表征参数与胴长、体质量间的生长关系不存在性别间显著性差异。赤池信息准则表明,TSL、LDL、MW与胴长、体质量的生长关系适用幂函数生长模型表示,WL与胴长、体质量的生长关系适用线性生长模型表示。随着太平洋褶柔鱼个体逐渐生长,其耳石整体外形轮廓的绝对尺寸生长逐渐减缓,但耳石整体外部轮廓的相对尺寸基本维持原状。本研究为后续利用耳石研究太平洋褶柔鱼的生活史过程提供了参考,也为研究异常气候事件对头足类硬组织生长的影响提供了科学依据。     

Methods for studying spatial behaviour of freshwater fishes in the natural environment

Spatial behaviour of fishes in fresh and brackish water ranges in temporal scales between localized diel movements, often associated with foraging and predator evasion, to seasonal or life‐cycle related events involving movements between freshwater habitats or freshwater and marine biotopes. Recent technological advances have resulted in dramatic improvements in the range of techniques available for the study of spatial behaviour of freshwater fishes in the natural environment, and broadly may be divided into two categories: capture dependent and capture independent. The former incorporates those methods that rely on sampling marked fish (mark–recapture) or unmarked fish (density estimates, catch per unit effort) over defined scales of time and space in order to derive information on distribution and movement. Captured fish may also be tagged with transmitters that radiate energy, enabling the fish to be tracked and/or environmental data to be gathered. Biochemical analysis of samples from fish, requiring non‐destructive sampling (genetic analysis and scale microchemistry) or destructive sampling (otolith microchemistry) may also provide information on migration and ontogenetic processes. Capture independent techniques include visual observation and video techniques, hydroacoustics and automated fish counting. Catch per unit effort and mark–recapture techniques are most efficient where long‐term fishery or monitoring studies are in place and data on crude spatial and temporal scales are acceptable. They also have the advantages of low technical requirements and low equipment costs. Where specific management or ecological questions are pertinent, recapture independent techniques may be more appropriate. Telemetric methods can provide high resolution information at the individual level, while hydroacoustics is increasingly providing information at the population level in large lake and river environments. Biochemical methods are becoming increasingly useful in determining the extent of population segregation, where DNA analysis is used, and in the study of migration and ontogenetic changes in behaviour, where otolith microchemistry and stable isotope analysis is used.     

Harnessing the potential for otolith microchemistry to foster the conservation of Amazonian fishes

1. Freshwater environments host roughly half of the world’s fish diversity, much of which is concentrated in large, tropical river systems such as the Amazon. Fishes are critical to ecosystem functioning in the Amazon River basin but face increasing human threats. The basic biology of these species, and particularly migratory behaviour, remains poorly studied, in part owing to the difficulty associated with conducting tagging studies in remote tropical regions.
2. Otolith microchemistry can circumvent logistical issues and is an increasingly important tool for studying fish life histories. However, this approach is still new in the Amazon, and its potential and limitations to inform fish conservation strategies remain unclear.
3. Here, otolith microchemistry studies in the Amazon are reviewed, highlighting current possibilities, and several key factors that limit its use as a conservation tool in the Amazon are discussed. These include the dearth of spatiotemporal elemental data, poor understanding of environment–fish–otolith pathways, and insufficient funding, facilities, and equipment.
4. A research initiative is proposed to harness the potential of this technique to support conservation in the Amazon. Key aspects of the proposal include recommendations for internal and external funding, which are critical to acquiring and maintaining technical staff, cutting-edge equipment, and facilities, as well as fostering regular scientific meetings and working groups. Meetings can facilitate a systematic approach to investigating environment–otolith pathways, broadening the chemical baseline for most Amazonian tributaries, and exploring potential valuable elements.
5. These outcomes are urgently needed to conserve biodiversity and ecosystem functioning in the Amazon, especially given threats such as widespread hydroelectric damming. The initiative proposed here could make otolith microchemistry an important, cost-effective tool to inform and foster conservation in the Amazon, and act as a template for other imperilled tropical river basins, such as the Mekong and the Congo.

     

Spawning areas and migration patterns in the early life history of Squalius cephalus (Linnaeus, 1758): Use of otolith microchemistry for conservation and sustainable management

1. In the context of the River Rhône restoration programme, the objective of this study was to assess the dispersal and population connectivity of the European chub, Squalius cephalus (Linnaeus, 1758) in a section of the natural, free-flowing part of the lower River Rhône.
2. The elemental water signatures for Sr:Ca and Ba:Ca were measured at seven stations within the river section, including its tributaries and backwaters, to determine whether they could be differentiated by microchemistry. From August to October the signatures differed among three sectors of the study reach: the Rhône; the Ardèche; and the backwaters.
3. The elemental signatures of the otoliths of 178 young-of-the-year (YOY) chub from the stations were measured to assess spawning areas and identify early migratory life histories. Analyses of otolith microchemistry identified the natal origin of 95% of the fish. Sr:Ca signatures of otoliths showed early downstream migration for 30.4% of the YOY chub; however, 70% of the fish recruited relatively close to their spawning origin suggesting a potential inshore retention of fish.
4. The results showed (i) a non-negligible contribution of the tributaries and backwaters in the recruitment of fish into the main channel; and (ii) the ability of chub to migrate over several kilometres during their first few months of life.
5. This study shows that the combination of water and otolith microchemistry analyses of fish growth increases the understanding of fish life history. Moreover, the study revealed that half of the YOY fish from this river section came from the tributaries and the other half came from reproduction in the River Rhône (despite its high anthropization).
6. These methods offer promising future applications of otolith microchemistry for river management in the context of ecological rehabilitation, especially to assess the effectiveness of measures applied in the restoration of floodplain connectivity for riverine fish population conservation.

     

Do Eurasian minnows (Phoxinus phoxinus L.) inhabiting brackish water enter fresh water to reproduce: Evidence from a study on otolith microchemistry

Dynamics of coastal fish assemblages in the Baltic Sea are still rather poorly understood. In particular, little information is available on migrations and movements of the small‐bodied littoral fish species like Eurasian minnow (Phoxinus phoxinus L.). Minnow is considered typically as a river and lake species, but it also inhabits brackish coastal waters of the Baltic Sea. In this study, we investigated movement patterns of brackish water inhabiting minnows using otolith microchemistry. Fish were collected from four different sites (from two bays and two stream mouths) around Saaremaa Island. The results indicated that at least three distinct migration patterns exist: (i) seawater residency, (ii) fast springtime migrations to fresh water or to bays with lower salinities (areas near stream mouths) and (iii) prolonged migrations to fresh water (some cases overwintering in streams). Migration patterns listed above were not evenly distributed among sites, and some individuals did not migrate to fresh water in every year. None of the analysed fish were freshwater residents. Additionally, potentially ontogenetic effects on Mn and Sr concentrations were observed in the otolith core regions, which may have important implications for the interpretation of otolith chemistry data. The overall findings of this study demonstrate that much more complex migration patterns exists in brackish water inhabiting minnow populations than previously thought and at least some individuals do enter freshwater to reproduce.     

脊椎骨在软骨鱼类年龄、摄食及洄游研究中的应用

软骨鱼类(鲨、鳐和银鲛类)多位居海洋食物网的顶端或近顶端, 通过下行效应调控海洋生态系统结构和功能, 多为生态系统中的关键性物种。脊椎骨是软骨鱼类支撑身体的重要硬组织, 其生长贯穿整个生活史, 主要应用于鉴定年龄。随着微化学技术的兴起, 并结合脊椎骨轮纹的特殊结构, 可进而掌握鱼类整个生活史中摄食及洄游信息。目前, 国内外基于脊椎骨的微化学研究主要集中在稳定同位素和微量元素分析, 并已取得一定的进展。本文在归纳国内外应用脊椎骨在软骨鱼类生长、摄食及洄游中的应用案例基础上, 着重分析了脊椎骨应用于年龄鉴定及校正、摄食及洄游等核心问题上的研究现状和发展前景, 以期为今后学者展开基于软骨鱼类脊椎骨的相关研究提供参考。     

南极鱼类年龄与生长研究进展

南极鱼类生长相对缓慢,独特的生物学特性使其年龄鉴定较其他海区鱼类更为困难。但考虑到鱼类年龄鉴定是开展渔业资源评估的基础,因此过去一些年来,硬质部位,如鳞片、鳍条(棘)、脊椎骨以及耳石等仍成为南极鱼类的主要鉴龄材料。本文对南极鱼类年龄鉴定的方法和材料进行了总结回顾,将年龄鉴定的方法和材料进行比较,分析各自优缺点。结果显示:(1)对于具鳞的南极鱼类,因鳞片在鱼类生长过程中存在重吸收现象,因而利用鳞片及鳍条(棘)单独鉴龄所得出的结果通常小于耳石的鉴龄结果,缺乏精确性;(2)南极鱼类生活跨度较大,高龄鱼体长频次分布严重重叠,以致无法准确判断其年龄结构;(3)耳石重量法易受到特殊个体影响而误判年龄;(4)因鳍条易损坏,脊椎骨采集较为困难,且许多南极鱼类无鳞,目前大多数南极鱼类使用耳石鉴定年龄,其也成为目前最为精准的南极鱼类鉴龄方法,但同时利用鳞片和耳石重量等对鉴定结果进行验证;(5)南极鱼类尚存在无统一的鉴龄标准、人为主观性较强以及缺乏早期生活史研究等不足之处;(6)为了研究南极鱼类早期生活史,耳石微化学及微结构等方法将被广泛利用。     

几种前处理方法所获刀鲚(Coilia nasus)耳石年轮的效果比较

本研究较为系统地比较了刀鲚(Coilia nasus)耳石的几种碾磨方法及耳石酸蚀前处理所获刀鲚耳石年轮的效果.结果显示,耳石横截面碾磨法更易获取较为清晰的年轮,而矢状面碾磨法的效果不及前者,但后者在用于耳石微化学的研究中却更有优势.经5％EDTA处理过的耳石,比用1％HC1处理过的耳石,更容易获得较好的年轮效果.本研究还发现,刀鲚耳石年轮形成过程中的一些形态变化,与刀鲚生活史中的生境变化有关联性.     

An otolith microchemistry study of possible relationships between the origins of leptocephali of European eels in the Sargasso Sea and the continental destinations and relative migration success of glass eels

Martin J, Daverat F, Pécheyran C, Als TD, Feunteun E, Réveillac E. An otolith microchemistry study of possible relationships between the origins of leptocephali of European eels in the Sargasso Sea and the continental destinations and relative migration success of glass eels.
Ecology of Freshwater Fish 2010: 19: 627–637. © 2010 John Wiley & Sons A/S Abstract – Little is known about the extent to which Atlantic eels coming from different European rivers converge on the same spawning site. Our aim was to evaluate the spatial homogeneity of eel spawning area(s) with an otolith microchemistry approach. This work compared the elemental signatures of otolith’s core region of Anguilla anguilla leptocephali caught in the Sargasso Sea in 2007 with those of glass eels and elvers sampled in European estuaries during 2006, 2008 and 2009. Using laser ablation inductively coupled plasma mass spectrometry, the same annular ablation trajectory along the first feeding mark was applied on otoliths of glass eels, elvers and leptocephali. The concentrations of thirteen isotopes in the otoliths of glass eels/elvers did not vary among three annual cohorts collected in eleven European locations. However, otolith elemental fingerprints of leptocephali differed significantly from glass eels otolith’s signature. Although the mechanisms that regulate the differences in trace element signatures among leptocephali and glass eels/elvers are unknown, we propose that the sampled glass eels/elvers were born in a spawning site or region where favourable transport and/or feeding conditions occurred. Conversely, the leptocephali may have been sampled in a less favourable region in the Sargasso Sea, with a low probability of reaching continental growth areas.     

Identification of stocked muskellunge and potential for distinguishing hatchery‐origin and wild fish using pelvic fin ray microchemistry

The effectiveness of pelvic fin ray microchemistry of muskellunge, Esox masquinongy Mitchill, to identify stocked individuals along with the potential to identify naturally reproduced fish were evaluated. Fish and water samples were obtained from one hatchery and seven lakes with natural differences in water Sr:Ca to determine whether location‐specific environmental signatures were recorded in sectioned muskellunge pelvic fin rays, including fish of known environmental history. Water and fin ray Sr:Ca were strongly correlated. Six lakes in Illinois possessed Sr:Ca signatures that were distinct from the hatchery where muskellunge were raised, resulting in pronounced shifts in Sr:Ca across sectioned fin rays of stocked fish. Hatchery and lake‐specific Sr:Ca signatures were stable across years. Sixteen of 19 individual fish known to have been stocked based on PIT tags implanted at stocking were correctly identified as hatchery‐origin fish using fin ray core Sr:Ca. Results also indicated that the hatchery Sr:Ca signal can be retained for at least 7 years in fin rays of stocked fish. Fin ray microchemistry is a non‐lethal approach for determining environmental history of muskellunge that could be used to assess movement patterns in lake and river systems and the degree to which muskellunge populations are supported by natural reproduction and stocking.     

长江短颌鲚耳石Sr/Ca值变化特征及其江海洄游履历

为确证长江刀鲚生殖洄游季节的短颌刀鲚是否为江海洄游个体,采用X射线电子探针微区分析技术(EPMA)研究了2013年4月27日采自长江靖江段的1尾短颌鲚(XGC-A)和1尾长颌鲚(XGC-B)矢耳石的锶(Sr)和钙(Ca)的微化学特征,同时将实验结果与确认是江海洄游型长江刀鲚矢耳石的Sr和Ca的微化学特征进行了比对分析。定量线分析结果显示,短颌鲚和长颌鲚个体的Sr/Ca值均波动显著,不仅具有对应淡水生活的低值(1.59±0.80、1.55±0.74),而且出现了对应于海水生活的高值(4.38±1.33、3.56±0.94),显示出其溯河洄游的履历;耳石元素面分布分析结果同时验证了短颌鲚和长颌鲚均参与江海洄游的事实。研究表明,目前长江中存在参与江海洄游的短颌鲚个体。