海洋鱼类摄食生态与食物网研究进展

首先总结归纳了海洋鱼类摄食生态与食物网研究中的实验方法,主要包括胃含物分析法、碳氮稳定同位素法、特定化合物同位素法等实验方法的发展历史和应用现状；随后介绍了海洋鱼类摄食生态与食物网最新研究进展和取得的成绩,主要包括海洋鱼类摄食生态中食物组成、摄食方式、摄食量和食物用于机体各种生命活动分配方式,以及海洋食物网研究中以传统胃含物分析法为基础、以简化食物网为核心,碳氮稳定同位素技术和生态系统模型的应用发展；最后,着重分析了我国海洋鱼类摄食生态和食物网研究中有待解决的问题,并对该领域今后的发展趋势进行了展望。     

稳定同位素模型在水生生态系统食物网中的研究进展

水生生态系统食物网具有错综复杂的营养关系。稳定同位素技术的发展对了解生物间的摄食关系和食物网结构发挥着极为重要的作用。其中，稳定同位素混合模型(stable isotope mixing models, SIMMs)近年来的迅猛发展为进一步解决水生食物网的复杂性问题提供了有力的手段，尤其是在确定食物来源贡献和构建营养生态位方面。在本研究中，作者综述了稳定同位素模型的发展历程、主要模型的特点以及运行这类模型的条件；同时，对稳定同位素混合模型在水生生态系统食物网领域中的应用前景与局限性进行了总结与展望，以期为相关研究者提供参考     

南极磷虾胃含物分析进展及其在食性研究中的应用

南极磷虾(Euphausia superba Dana)丰富的生物量和所处食物网中的重要地位使之成为南极生态系统中的关键物种, 其生态作用和摄食活动越来越受到重视。南极磷虾是典型的植食性浮游动物, 同时也具有一定的杂食性, 其摄食对象会因所在海域优势浮游植物种类不同而有所差异, 有着作为浮游植物自然采样器的潜力。有关南极磷虾胃含物研究已有较长的历史, 但研究内容存在着显著的时空异质性, 研究区域极为零散, 且环南极分布不均。随着食性研究领域新兴方法的应用, 胃含物分析因方法费时、劳动密集, 且需高水平的专业知识和经验, 近年来缺乏及时且必要的研究。但作为一种检验南极磷虾短期内摄食的直接手段, 将胃含物分析这种传统的食性研究方法与脂质生物标记物、稳定同位素、聚合酶链反应(PCR)等新兴方法相结合, 可以突破单种方法的局限性, 并为后续开展相关研究提供更为准确且全面的摄食生态学信息。本研究从南极磷虾胃含物研究现状、研究方法与应用、胃含物主要组成及季节、海区、个体差异等方面进行总结和归纳, 并进一步探讨了南极磷虾作为南大洋浮游植物采集器的潜力, 为之后研究南极海洋生态系统营养动力学提供科学依据。     

鱼类早期发育阶段摄食行为研究现状

对鱼类早期阶段的摄食行为研究进行了综述。重点阐述了胃含物分析法、饥饿对摄食的影响、摄食器官的形态发育特征与摄食行为的关系、食物选择及其生理生态因子对摄食的作用。初步探讨了仔稚鱼饥饿后的捕食量和捕食速度的变化,并结合食物保障,分析了食物选择性指数I在鱼类摄食行为研究中的应用。     

DNA条形码在马鞍列岛海域皮氏叫姑鱼胃含物鉴定中的应用

采用分子生物学手段与传统观测手段相结合的方法,对2014年夏季在马鞍列岛海域捕获的201尾皮氏叫姑鱼进行了胃含物分析。解剖后发现其空胃率较高,传统的观测方法仅获得口虾蛄、日本鼓虾、沙蚕、日本蟳幼体4种胃含物,所获得的胃含物中存在大量不可辨认的虾类、蟹类。针对不可辨认的食物糜提取组织DNA,选用线粒体基因细胞色素C氧化酶亚基Ⅰ(mitochondrial cytochrome oxidase subunitⅠ,COⅠ)作为分子标记,在Gen Bank中进行比对分析,并利用MEGA 6.0构建NJ系统进化树,结果鉴定出中华管鞭虾、鲜明鼓虾、巨指长臂虾、日本鼓虾、中国毛虾、褐菖鲉、日本鳀等10种胃含物种类,实验中所获得的基因序列在Gen Bank中的相似度达到97%以上。通过对不可辨认糜的鉴定,在较大程度上解决了对食物团中不可辨认成分鉴定的困惑;同时,发现了新的摄食对象,了解到更加多样的皮氏叫姑鱼的摄食种类信息。因此,DNA条形码技术在不可辨认饵料生物鉴定中的应用价值应得到重视。     

基于DNA分子生物学食性研究领域的文献计量分析

食物网及其动态变化研究有助于理解群落生态学和生态系统的功能机制,而运用准确的技术手段来确定消费者的生态位宽度和食物组成对该领域研究至关重要[1 ].目前关于食性分析方法主要分为3类:传统方法(直接观察、消化道内容物分析和显微镜镜检等)、生化方法(脂肪酸组成分析和稳定同位素分析等)和分子方法(同工酶电泳、单克隆抗体与多克...     

长江口及南黄海水域春季生物摄食生态的稳定同位素研究

根据长江口及毗邻南黄海水域多种生物的碳稳定同位素比值，计算其摄食生态类型，结果表明，一些生物的摄食生态类型计算结果存在时空与计算方法差异，其原因是生物的食性存在季度或年际上的时间变化，并会随栖息环境的变化而相应发生改变；统一稳定同位素法与胃含物分析法计算生物摄食生态的判断类型后，2种方法计算的结果基本一致，24种共有生物有21种生物的判断结果一致，推断稳定同位素法计算生物摄食生态类型可行。     

凤凰山天池断线麦穗鱼的摄食生态研究

为了解断线麦穗鱼(Pseudorasbora interrupta)在凤凰山天池的种群生物学特征,对其基础生物学特征进行了系统研究。2016年4月-2017年3月,于凤凰山天池共采集断线麦穗鱼281尾,利用胃(肠)含物分析法,分析其摄食强度、食物组成和摄食生态位。结果表明:断线麦穗鱼的摄食强度春季最低,夏、秋季较高,春秋季节差异明显。其饵料生物包括18个类群,以硅藻门占绝对优势(IRI=79.25%),其余依据IRI大小依次为绿藻门、水生昆虫、枝角类、甲藻门等。断线麦穗鱼的食物组成呈现季节变化,除全年均占绝对优势的硅藻外,次优势类群的四季差异明显。其中春季以水生昆虫和花粉较为常见;夏季以绿藻门和甲藻门较为常见;秋季以枝角类最多;冬季则为绿藻门占优。以特定饵料丰度和出现频率作图对摄食策略分析结果表明:断线麦穗鱼属于广食性鱼类,具有较为宽广的营养生态位。     

黑龙江黑斑狗鱼的食性及其随体长和空间的变化

为了解黑斑狗鱼（Esox reicherti Dybowski）的食性及其随体长和空间的变化，2022年10—11月用网目2～8 cm的流刺网和网目0.9～3.5 cm的定置刺网在黑龙江抚远和呼玛江段采集到138尾黑斑狗鱼，鉴定和测量其体长和体质量及胃含物种类与重量，研究摄食习性及其随体长和空间的变化。结果表明：这些黑斑狗鱼的饵料生物共有27种（包含未鉴定种），分为5个类群：鱼类、两栖类、甲壳类、水生昆虫和其他饵料，其中鱼类为黑斑狗鱼最主要的食物类群，数量在食物中占90.17%,然后依次为两栖类、水生昆虫和甲壳类。食物类群随着黑斑狗鱼的体长增加存在不显著的差异。体长350～450 mm组黑斑狗鱼主要摄食幼鱼；体长450～550 mm之间时开始摄食的饵料鱼个体增大，还摄食两栖类和少量水生昆虫；550～650 mm体长组的黑斑狗鱼则全部以鱼类为食。不同空间的黑斑狗鱼食物组成无明显差异。平均饱满指数和空胃率结果显示，黑斑狗鱼的摄食强度随着其体长的增长显著变化，摄食的高峰期在450～550 mm体长组之间，摄食强度无明显的空间差异。     

秋季额木尔河江鳕的摄食生态

2022年10月，用网目1～3 cm的定置刺网和网目4.0 mm的地笼在额木尔河流域捕获148尾江鳕（Lota lota），体长107.0～372.0 mm，体质量8.91～372.36 g。取其胃含物进行食性鉴定，采用传统胃含物分析法，通过质量百分比、数量百分比、出现频率和相对重要性指数等指标，分析江鳕的食物组成和摄食强度，及其随体长和空间变化特征，为江鳕的资源保护提供参考。结果表明，额木尔河江鳕主要以鱼类、水生昆虫和甲壳类等食物类群为食。江鳕的食物组成随着体长的增加食性明显转换，鱼类的质量百分比逐渐增加，水生昆虫质量百分比逐渐减少。不同体长的江鳕平均饱满指数和空胃率均未随体长而显著变化（P>0.05）。额木尔河流域江鳕的食物组成在空间分布上未出现明显的食性转换，不同空间的平均饱满指数（P>0.05）和空胃率（P>0.05）差异不显著。     

Generalist feeding strategies in Arctic freshwater fish: A mechanism for dealing with extreme environments

Generalist feeding strategies are favoured in stressful or variable environments where flexibility in ecological traits is beneficial. Species that feed across multiple habitat types and trophic levels may impart stability on food webs through the use of readily available, alternative energy pools. In lakes, generalist fish species may take advantage of spatially and temporally variable prey by consuming both benthic and pelagic prey to meet their energy demands. Using stomach content and stable isotope analyses, we examined the feeding habits of fish species in Alaska's Arctic Coastal Plain (ACP) lakes to determine the prevalence of generalist feeding strategies as a mechanism for persistence in extreme environments (e.g. low productivity, extreme cold and short growing season). Generalist and flexible feeding strategies were evident in five common fish species. Fish fed on benthic and pelagic (or nektonic) prey and across trophic levels. Three species were clearly omnivorous, feeding on fish and their shared invertebrate prey. Dietary differences based on stomach content analysis often exceeded 70%, and overlap in dietary niches based on shared isotopic space varied from zero to 40%. Metrics of community‐wide trophic structure varied with the number and identity of species involved and on the dietary overlap and niche size of individual fishes. Accumulation of energy from shared carbon sources by Arctic fishes creates redundancy in food webs, increasing likely resistance to perturbations or stochastic events. Therefore, the generalist and omnivorous feeding strategies employed by ACP fish may maintain energy flow and food web stability in extreme environments.     

Trophic Ecology of Arapaima sp. in a ria lake—river–floodplain transition zone of the Amazon

Neotropical floodplains are usually productive systems that are maintained by the nutrient, detritus and sediment inputs provided by the main river channel flood pulse. Ria lakes represent a special feature and habitat in the Amazonian floodplains, being characterised by a dendritic morphology and dependence on terrestrial inputs provided by an intricate stream network. Our objective was to evaluate the trophic ecology of the arapaima (Arapaima sp.). We combined stomach content analysis with measurements of carbon and nitrogen stable isotope values from dorsal muscle to infer the ontogenetic changes in trophic level and isotopic niche width in floodplain and ria lakes. Arapaima diet was dominated by fish from low trophic positions. While most of the stomachs sampled in the study ria lake were full, empty stomachs predominated in samples taken in the floodplain lakes. These differences indicate that ria lakes may provide better feeding grounds for arapaima during the dry season, presumably because ria lakes are interconnected with a large stream network and the main river channel year round. Nitrogen stable isotope results further indicated an ontogenetic dietary shift in arapaima, with piscivory increasing as a function of length in both environments. Carbon stable isotope analysis indicated that energy sources used by arapaima varied by environment, with arapaima using a greater diversity of food sources in ria lakes than in floodplain lakes. Information about the main carbon sources is useful for fishery management because stakeholders may choose to conserve key vegetal groups to ensure the productivity and diversity of aquatic ecosystems.     

Individual and spatial variation are as important as species‐level variation to the trophic complexity of a lentic food web

Ecological complexity may improve ecosystem function, stability and adaptability to natural and anthropogenic disturbances. Intraspecific trophic variation can represent a significant component of total community variation and can influence food web structure and function. Thus, understanding how trophic niches are partitioned between intraspecific and interspecific processes could improve our understanding of food web dynamics. We examined gut contents, fatty acids and stable isotope ratios in round goby (Neogobius melanostomus) and yellow perch (Perca flavescens) across six sites in Lake Michigan, USA, to determine patterns in intra‐ and interspecific trophic composition (i.e., mean gut or fatty acid composition) and diversity (i.e., the diversity of gut items or fatty acids). We also examined relationships between fatty acid diversity and gut content characteristics to understand potential mechanisms shaping individual trophic phenotypes. There was significant variation in both trophic composition and diversity among sites, and individual and spatial variation was as important to total trophic variation as species identity. Round goby that consumed dreissenid mussels had more diverse fatty acid profiles than those that consumed other benthic invertebrates, whereas yellow perch fatty acid diversity was not related to gut content composition. Our results confirm that intraspecific variation in resource use can be as important to trophic dynamics as interspecific variation, and that spatial variation in lower level food web processes or habitat may strongly structure local food web dynamics. Individual‐level examination of trophic diversity, in concert with trophic composition, could provide additional information about the resilience, function and adaptability of local food webs.     

Trophic structure of a pond community dominated by an invasive alien species: Insights from stomach content and stable isotope analyses

1. Invaders affect native species across multiple trophic levels, influencing the structure and stability of freshwater communities. Based on the ‘trophic position hypothesis’, invaders at the top of the food web are more harmful to native species via direct and indirect effects than trophically analogous native predators are.
2. However, introduced and native predators can coexist, especially when non-native species have no ecological and behavioural similarities with natives, occupy an empty niche, or natives show generalist anti-predator strategies that are effective at the community level.
3. At present, conservation efforts are focused on eradicating invaders; however, their removal may lead to unwanted and unexpected outcomes, especially when invaders are well established and strongly interspersed with natives. This highlights the need to consider invaders in a whole-ecosystem context and to consider the evolutionary history and behavioural ecology of natives and invaders before active management is applied.
4. Here, stomach content and stable isotope analyses were combined to investigate a pond system dominated by invaders in order to understand the effects of the interactions among upper level predators and lower level members of the food web on the whole community structure.
5. Both diet and isotope analyses showed that several invaders contributed to the diet of natives and invaders. A significant isotope overlap was found among upper level predators. However, stomach content analysis suggested that predators reduced the potential competition differentiating the food spectrum by including additional prey in their diet. Both native and non-native upper level predators, by preying on invaders, seem not to exert a strong suppressive effect through predation and competition on native species.
6. This research confirms the importance of studying food webs to identify ecological conditions that forecast the potential for deleterious impacts before management is applied. In cases where invaders cannot be eradicated, management efforts should follow a conciliatory approach promoting the coexistence of native species with invaders.

     

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。     

Dietary map of Nile tilapia using stable isotopes in three tropical lakes,Ethiopia

Comprehensive analysis of food webs requires identifying dietary sources that support the production of all major organisms within the food web/food chain. Here, we use stable isotope ratios (δ¹³C, δ³⁴S and δ¹⁵N) to assess the relative contribution of different basal carbon sources to the diet of Nile tilapia (Oreochromis niloticus L.) in three tropical lakes Hawassa (also Awasa in literature), Ziway and Koka (Ethiopia). Computations were carried out with Stable Isotope Analysis in R (SIAR) model to quantify the dietary proportion of each prey for the tilapia fish. Basal food sources were distinguishable based on their δ¹³C, δ³⁴S and δ¹⁵N values. In Lake Ziway, macrophytes (64%) were the dominant assimilated diet of tilapia while particulate organic matter (POM) and zooplankton contributed only 20% and 16%, respectively. In parallel, Nile tilapia in Lake Hawassa assimilated macrophytes (35%), POM (33%) and zooplankton (32%) at comparatively equal proportion. The dietary sources of the fish in Lake Koka were POM (49%) and zooplankton (51%). In contrast with earlier studies based on gut content analysis, the present results reveal that macrophytes contributed more and phytoplankton less than previously reported especially in macrophyte‐dominated lakes Ziway and Hawassa. The ecological condition of the lakes might have been predominantly accountable for the diet change of the tilapia. As dietary data are prerequisite for food web/food chain analysis and aquaculture industry, re‐evaluating the diet of aquatic organisms appear relevant.     

Seasonal and spatial variations of the food web structure in a shallow eutrophic lake assessed by stable isotope analysis

Stable isotope analysis was used to investigate seasonal and spatial variations of the food web structure in a large eutrophic lake ecosystem (Lake Taihu, China). Basal food sources, invertebrates and fish were sampled in two lake regions with different environmental conditions and spatial variations in the isotopic composition of lake food webs were found. Overall, more depleted δ¹³C and enriched δ¹⁵N isotope values of organic matter sources and consumers were found in the phytoplankton-dominated lake region than in the macrophyte-dominated region. Wide seasonal variations in the isotopic ratios were also observed in the lake biota, with a general trend towards enriched δ¹³C and δ¹⁵N values in summer and depleted values in winter. This pattern could be explained by a combination of environmental (e.g., irradiance and nutrient inputs) and biotic (e.g., availability of food sources and plasticity in prey item choice) features. Results of isotope mass balance suggest that macrophytes provide some trophic support in the macrophyte-dominated area, but in both lake regions it is more likely that aquatic food webs are phytoplankton based rather than macrophyte based under eutrophic conditions.     

Diet composition of the Italian crested newt (Triturus carnifex) in structurally different artificial ponds based on stomach contents and stable isotope analyses

1. In order to evaluate the effects of ecological disturbances, such as climate change, human‐induced habitat modification, or species introduction, and in order to adopt appropriate management policies for their conservation, knowledge of the trophic ecology of protected or threatened species is crucial. The Italian crested newt, Triturus carnifex (Laurenti, 1768), is listed in annexes II and IV of the European Habitats Directive. For this species, changes in water quality and habitat loss represent major threats, potentially impairing its breeding and feeding activities.
2. Artificial aquatic habitats, such as cattle‐drinking pools, represent valuable refuges and suitable breeding sites for T. carnifex. The aim of this study was to determine the food niche of the Italian crested newt in these habitats, evaluating its prey selection strategy in relation to a range of environmental conditions and differing availability of resources. Stomach contents (indicative of short‐term diet) and δ¹³C and δ¹⁵N signatures of tails (indicative of medium‐term diet) of adult newts from three artificial ponds in central Italy, where traditional silvo‐pastoral activities are still important, were determined. Potential prey were also sampled and processed for stable isotope analysis.
3. Triturus carnifex, similar to other newt species, is an opportunistic predator, feeding on a wide variety of prey that includes terrestrial and aquatic macroinvertebrates. In particular, the opportunistic use of temporally available small zooplankton was identified from stomach contents analysis. Conversely, stable isotope analysis highlighted the consumption of larger, soft‐bodied prey that the stomach‐contents‐based approach underestimated. These included terrestrial oligochaetes, which turned out to be the most important and energy‐rich food source in the medium term.
4. These results emphasize the usefulness of combined approaches for studying the trophic ecology of salamanders and also highlight the importance of the integrated management of aquatic breeding habitats and neighbouring terrestrial habitats, as sources of food, for newt conservation.