我国伊犁河鱼类群落结构及外来鱼类适生性

2012-2019年,在我国伊犁河流域的6个断面开展了鱼类群落结构调查,结果显示我国伊犁河流域现有鱼类共计29种,大多属于鲤形目。鱼类群落组成与20世纪末期相比发生了变化,银色裂腹鱼、短头鲃、银鲫、鲢、北方泥鳅在本研究中未出现,尤其是银色裂腹鱼,截至目前为止的鱼类资源调查中,均无捕获记录。历史研究中未见的乌鳢与大口鲇在本研究中有捕获。外来鱼类的出现率和数量均有所增加。对鱼类群落结构特征进行分析,显示伊犁河流域鱼类群落多样性较低,下游干流和上游支流的鱼类群落结构差异较大。现阶段,我国伊犁河流域主要的优势种外来鱼类有鲤、和鲫。利用最大熵生态位模型（MaxEnt）对鲤、和鲫的适生区域进行预测,与鱼类资源调查获得的鱼类实际分布区对比,显示鲤和在我国伊犁河流域的分布范围与预测结果是吻合的,而鲫在进入伊犁河流域之后开始向上游支流河段扩散。由于这几种外来鱼类在一开始引入的时候未采取管控措施,又具有极强的适应能力,且伊犁河流域的鱼类多样性较小,因此极易形成规模并扩散。外来鱼类的入侵,会对土著鱼类造成巨大的威胁。基于本论文研究结论,应当将已发生生态位漂变的鲫其作为重点关注种类,关注外来鱼类的生活史对策,深入研究外来鱼类的入侵机制和诱因;对上游支流河段的生境进行监测,关注气候和水文变化,尤其是土著鱼类产卵场、索饵场和越冬场的变化,尽可能减小人类活动干扰;对伊犁河流域的鱼类资源进行长期监测,关注鱼类群落结构变化,一旦发现异常及时采取措施;增加对土著鱼类的增殖放流;严格控制进出口贸易和增殖放流时夹带的外来鱼类。维护我国伊犁河流域的生态安全。     

新疆伊犁河不同河段鱼类的物种多样性和优势种

为了了解伊犁河鱼类群落结构和多样性特征, 于2012—2014年连续3年对我国境内新疆伊犁河上、中和下游不同河段进行鱼类资源调查。获得27种鱼类样本, 隶属于6目9科23属。伊犁河中、上游河段主要以斯氏高原鳅、新疆裸重唇鱼、新疆高原鳅和伊犁裂腹鱼等土著鱼类为优势种, 下游河段的优势种主要有鲤、草鱼和鲫等外来种。伊犁河中、上游河段鱼类种类稀少, 大中型鱼类资源稀少, 鱼类群落多样性低。梯级水电站的开发、过度捕捞以及外来种入侵对伊犁河鱼类鱼类群落造成了很大的影响。     

雅砻江中游支流力丘河鱼类资源现状

为了解雅砻江中游支流力丘河的鱼类多样性现状及栖息地保护价值,于2019年9月和2020年6月、11月在力丘河11个采样点进行了3次鱼类资源调查,共采集鱼类2 557尾,隶属于2目4科9属13种。西溪高原鳅Triplophysa xiqiensis、软刺裸裂尻鱼Schizopygopsis malacanthus、短须裂腹鱼Schizothorax wangchiachii和齐口裂腹鱼Schizothorax prenanti数量较多、分布较广,其余种类仅有零星分布。丰度/生物量比较曲线表明,力丘河鱼类群落受到中等程度干扰。Spearman秩相关性系数显示,鱼类多样性与海拔呈显著负相关。非度量多维标度分析表明,不同海拔区域的鱼类群落空间结构差异显著,雅砻江干流的许多鱼类仅分布到力丘河下游普沙绒乡罗让以下河段,力丘河中游甲根坝乡以上河段及塔拉沟、色物绒沟等支流仅分布有西溪高原鳅和软刺裸裂尻鱼。由于相对较低的鱼类多样性、严酷的生态环境和海拔对鱼类分布的限制,力丘河作为雅砻江中游干流水电开发后鱼类栖息地的保护价值将一定程度降低,建议同时考虑雅砻江干流鱼类栖息地的保护。     

基于转录组测序的缺须盆唇鱼微卫星标记特征分析

缺须盆唇鱼(Placocheilus cryptonemus)是云南省怒江流域特有的一种高原经济鱼类.通过在Illumi-naHiSeq 2500平台上对缺须盆唇鱼进行转录组测序(RNA-seq)分析,利用MicroSAtellite (MISA)微卫星识别工具对1～6个碱基重复、碱基数在10 bp以上的微卫星进行鉴定.结果 表明,在缺须盆唇鱼转录组中共发现分布在36764条Unigene上的30500个SSR位点,包含序列的SSR数量为18078,发生频率为49.17％.获得的单纯SSR中共有215种重复基元,其中单核苷酸重复基元类型数量最多,为88个,六碱基重复的SSR最少,其他的重复从二、三、四、五、六碱基开始,SSR的形成呈现递减规律.SSR位点的重复次数主要发生在6～10次和11～15次重复之间,发生频率分别为38.59％和36.02％.本研究对缺须盆唇鱼的转录组数据进行测序鉴定,得到了数量较多的SSR标记,同时对得到的缺须盆唇鱼SSR数据特点进行归纳总结.本研究不仅提供了一个有价值的转录组资源,而且建立了一套SSR标记,可以为缺须盆唇鱼的基础研究、应用研究提供有效的分子标记.     

黄河流域鱼类食性同资源种团的时空变化

鱼类资源保护是黄河流域生态保护和高质量发展的重要环节。通过历史资料整理和野外调查发现,1960—2019年,黄河流域共分布鱼类16目35科201种。其中,鲤形目物种数最多,占比60.7%;鲈形目次之,占比10.0%。1960—1980年分布鱼类15目28科182种;1980—2019年分布鱼类10目23科112种。源区、中游和下游鱼类物种总数显著降低,上游河段略有升高。两个时期间源区、上游、中游和下游的鱼类物种相似度指数分别为34.2%、46.0%、42.4%和35.7%。依据鱼类摄食偏好将黄河鱼类划分为8个食性同资源种团:着生藻类食性、草食性、浮游植物食性、浮游动物食性、杂食性、水生昆虫食性、软体动物食性和鱼食性。相较1960—1980年,1980—2019年间黄河流域水生昆虫食性鱼类占比显著降低;着生藻类食性、草食性、浮游植物食性、杂食性和鱼食性鱼类占比显著升高。1960—1980年,水生昆虫食性鱼类在源区和上游占比较高,于海拔2000～3000 m的河段开始沿河流连续统降低;而鱼食性鱼类在源区和上游占比较低,于海拔2000～3000 m的河段开始沿河流连续统升高。1980—2019年,水生昆虫食性鱼类占比自源区沿河流连续统呈线性降低趋势;鱼食性鱼类占比自源区至中游升高,在下游降低。梯级水电开发、水质污染、流量不足、酷鱼滥捕和外来鱼类入侵是造成黄河鱼类食性同资源种团时空变化的重要因素。     

赤水河鱼类资源的现状与保护

赤水河是长江上游右岸一级支流,为长江上游珍稀特有鱼类国家级自然保护区的重要组成部分。为了了解赤水河鱼类资源现状,于2007年4-10月在赤水河流域进行了鱼类资源调查。在干、支流共51个采样点采集了鱼类标本;对茅台镇、赤水市和合江县三个江段的渔获物进行了统计和分析。共采集到鱼类119种(亚种),隶属于5目16科75属。其中25种为该水域的新记录;34种为长江上游特有鱼类,尤其是宽唇华缨鱼(Sinocrossocheilus labiatus)仅分布于赤水河。在上、中、下游分别采集到鱼类36、61和100种。宽鳍鱲(Zacco platypus)、中华倒刺鲃(Spinibarbus sinensis)、光泽黄颡鱼(Pelteobagrus nitidus)、张氏(Hemiculter tchangi)和蛇鮈(Saurogobio dabryi)为赤水河中主要的经济鱼类,同时,各江段渔获物的组成也存在一定的差别。本研究表明,赤水河流域鱼类种类相对丰富,但过度捕捞和涉水活动导致鱼类资源出现了一定程度的衰减。     

对黑龙江省渔业的简短意见

1957和1958年,我极其荣幸地参加了研究与黑龙江流域水利建设有关问题的中苏综合考察队,与中国鱼类学家一起工作。我们这个人数不多的小组的主要任务是研究松花江中鱼类的繁殖特性,鱼卵、鱼胚和鱼苗的发育和漂流规律。研究这些问题,对于预报泾流调节对松花江和黑龙江中鱼类资源的影响以及在水利建设中应进行何种增殖措施,是很必要的。     

云南元江水系三条支流鱼类β多样性比较

元江水系具有代表性的３条支流南溪河、绿汁江、李仙江共有土著鱼类８２种,分隶于１５科,６０属。研究中将每条支流视为一个样本。对这３条支流鱼类从种和属两个层次进行β多样性指数分析。结果表明：绿汁江与李仙江相比,鱼类多样性差异不大：它们分别与南溪河相比,鱼类多样性差异性均十分明显。绿汁江与李仙江鱼类的共有种、属最少,它们的种分化隔离程度最大;南溪河与绿汁江共有种、属最多,它们的种分化隔离程度最小。它们的     

长江武穴江段鱼类早期资源现状

鱼类早期资源调查聚焦于揭示鱼类的产卵与仔鱼阶段的时空分布特征,如产卵持续时间、产卵场位置,其研究结果对渔业资源科学的保护与管理具有重要的指导意义[1]. 长江水系是我国淡水鱼类最重要的栖息地和繁殖场所之一,包括四大家鱼、鳊、铜鱼等多种重要经济鱼类.     

长江上游青衣江支流周公河鱼类资源现状

为了解长江上游青衣江一级支流周公河的鱼类资源现状,于2015年4月—2016年2月对周公河18个采样点进行了5次调查,共采集鱼类4 924尾,隶属于3目8科27属34种。其中,鲤形目Cypriniformes 20属24种,鲇形目Siluriformes 6属8种,鲈形目Perciformes 1属2种;鲤形目中鲤科Cyprinidae鱼类最多,共15种,占总种数的44. 12%。四川省重点保护鱼类有重口裂腹鱼Schizothorax (Racoma) davidi 1种,长江上游特有鱼类9种,列入《中国脊椎动物红色名录》的鱼类有重口裂腹鱼(濒危EN)、齐口裂腹鱼S.(S.) prenanti (易危VU)和白缘Liobagrus marginatus(易危VU)。周公河现有分布的鱼类以小型种类为主,钝吻棒花鱼Abbottina obtusirostris和宽鳍Zacco platypus为优势种。梯级水电开发可能对周公河鱼类资源造成了不利影响。     

Comparison of in vitro and in vivo effects of different species specific GnRH and their analogs

Mammalian, salmon and chicken gonadotropin-releasing hormones (mGnRH, sGnRH, cGnRH) and their analogs were synthesized and tested for their ability to stimulate in vitro LH and FSH release from cultured and superfused rat pituitary cells and also their in vivo effect were investigated on the artificial propagation of fishes. The LH and FSH releasing activity of sGnRH, cGnRH and their analogs were lower than the appropriate mammalian ones from cultured rat pituitary cells, but two of the cGnRH analogs showed increased LH and FSH secretory activity from superfused rat pituitary cells compared to the mGnRH. At the same time these two analogs are very potent to stimulate reproductive function of fishes and using these peptides we were able to fulfill the artificial propagation of fishes which could not be artificially propagated before.     

Behavioural syndromes in fishes: a review with implications for ecology and fisheries management

This review examines the contribution of research on fishes to the growing field of behavioural syndromes. Current knowledge of behavioural syndromes in fishes is reviewed with respect to five main axes of animal personality: (1) shyness-boldness, (2) exploration-avoidance, (3) activity, (4) aggressiveness and (5) sociability. Compared with other taxa, research on fishes has played a leading role in describing the shy-bold personality axis and has made innovative contributions to the study of the sociability dimension by incorporating social network theory. Fishes are virtually the only major taxon in which behavioural correlations have been compared between populations. This research has guided the field in examining how variation in selection regime may shape personality. Recent research on fishes has also made important strides in understanding genetic and neuroendocrine bases for behavioural syndromes using approaches involving artificial selection, genetic mapping, candidate gene and functional genomics. This work has illustrated consistent individual variation in highly complex neuroendocrine and gene expression pathways. In contrast, relatively little work on fishes has examined the ontogenetic stability of behavioural syndromes or their fitness consequences. Finally, adopting a behavioural syndrome framework in fisheries management issues including artificial propagation, habitat restoration and invasive species, may promote restoration success. Few studies, however, have examined the ecological relevance of behavioural syndromes in the field. Knowledge of how behavioural syndromes play out in the wild will be crucial to incorporating such a framework into management practices.     

Protection against lethal freezing temperatures by mucus in an Antarctic limpet

The antarctic limpet, Patinigera polaris, is sometimes caught in near-shore ice and exposed to temperatures substantially below ?2 °C. In-frozen animals always secrete an envelope of mucus which prevents extracellular ice propagation down to ?10 °C. Survival in limpets without mucus protection is significantly lower. Ice propagation through limpet mucus is retarded below its equilibrium freezing point in a manner similar to polar fishes. The capacity of mucus as a cryoprotectant has not previously been described.     

Acquisition of fishes and aquatic invertebrates for zoological collections. Is there a future?

The majority of the freshwater fishes in the ornamental trade now originate from captive‐bred sources, as do a large proportion of the freshwater species exhibited in public aquariums. In contrast, commercial operators who also supply marine specimens to the ornamental trade remove directly from the wild approximately 98% of the marine fishes and invertebrates exhibited in public aquariums. The common perception prevails that captive propagation is inherently a better alternative to obtaining animals from the wild. Although captive propagation has been shown to have many benefits for terrestrial species, there are a number of features unique to marine species that challenge the idea that every species should be bred in captivity. Some of the key issues relating to the development of widespread conservation‐oriented captive propagation programs include: 1) the high taxonomic diversity in marine animals; 2) the resultant variety in their reproductive methods; 3) their ecological, behavioral, physiological, and nutritional needs; and 4) our general lack of knowledge on their husbandry and medical care. There are several characteristics of marine fish and invertebrate populations that make them suitable candidates for sustainable harvest. For instance, marine teleosts are “r‐selected,” meaning that they have an extremely high fecundity, and most marine teleosts have a wide distribution and the ability to disperse over long distances. In locations considered for fish collection, appropriate management techniques should be employed to ensure that fishes and invertebrates are collected with as little impact on the ecosystem as possible. The collection of marine fishes and invertebrates for public aquariums and the hobby trade should be managed like a fishery to ensure long‐term sustainability. The public aquarium community should support marine organism certification initiatives, such as the Marine Aquarium Council (MAC). Marine organism certification will create market incentives that encourage and support quality and sustainable practices by creating consumer demand and confidence for certified organisms, practices, and industry participants. The creation of refuges that supply propagules to harvested areas, the rotation of areas fished, species‐specific size limits and seasons, and standardization of collecting, handling, and transportation techniques should be used to manage these fisheries and harvest areas. Zoo Biol 22:519–527, 2003. © 2003 Wiley‐Liss, Inc.     

African lakes and their fishes: conservation scenarios and suggestions

Synopsis Man has been associated with a variety of lakes throughout his evolutionary history in Africa. Lakeside dwellers have a close association with and understanding of these lakes. In the past four decades, however, overexploitation, introductions of alien fishes and the possibility of oil pollution present frightening prospects of irreversible losses and massive extinction. The development of scientific understanding of the life support processes, the ecosystems and the rich communities of these lakes has been so outpaced by exploitation and manipulations that accurate predictions regarding the future are impossible. Shallow lakes are more sensitive to physico-chemical changes caused by climatic as well as agricultural and industrial development than deep lakes, but their biotae are endowed with a resilience which facilitates recovery from major depletions to population size. In contrast, the speciose endemic cichlid faunae of deep lakes are sensitive to fishing pressure, are awkward to manage and should be regarded as representing a much smaller resource than initially imagined. The clupeids of Lake Tanganyika can sustain intensive fishing, but their introduction into other natural lakes is not recommended. Enormous changes to native faunae followed the introduction of Lates niloticus to lakes Kyoga and Victoria with dramatic consequences for the fisheries, for the socio-economic status of the region and for the maintenance of biotic diversity. Extinction of almost 300 fish species is a possible further consequence of L. niloticus predation. Intensive selective fishing for L. niloticus is being initiated, but is unlikely to resolve the problem. In the time necessary to substantially reduce L. niloticus, numerous endemic fishes may suffer extinction. A viable alternative to extinction of these species is captive propagation. Conservation of fishes by captive propagation is not a common or well documented practice. To encourage the acceptance of this conservation option a theoretical scenario in which the concepts and protocols are applied to the fishes of Lake Victoria is given. The possibility of returning rescued populations to the lake at a later date, assuming L. niloticus populations have been reduced, is also discussed. It is recommended that captive propagation should be practised to conserve species and to retain the option of returning rescued taxa. Scientists are urged to seek the funding to study tropical ecosystems so that conservation and rational development may acquire a sound foundation.     

The conservation of the fishes of Lake Victoria,Africa: an ecological perspective

Synopsis The African Great Lakes are considered to be dynamically fragile ecosystems that are relatively resistant to minor changes with which they have co-evolved but vulnerable to major perturbations such as overfishing, the introduction of alien species and pollution. These lakes are inhabited by large species flocks of cichlid fishes which are characterised by a complex structure of interaction both between and within species, as is typical of mature ecosystems. Major perturbations, such as the disruption of trophic interactions through the introduction of alien fishes, may reverse the domination of relatively precocial, specialised forms and result in the creation of conditions that are conducive to the survival of more altricial, generalised forms with strong colonising abilities. The introduction of Nile perch and Nile tilapia, as well as other alien fishes, into Lake Victoria, combined with overfishing for the indigenous cichlid species, has resulted in marked changes to the fish communities and the fisheries that depend on them. The most important impacts of the Nile perch appear to be predation and aggressive effects whereas those of the tilapias include hybridization, overcrowding, competition for food and possibly the introduction of parasites and diseases. While the three proposed methods of conserving the indigenous flocks of cichlid fishes (captive propagation, reducing Nile perch stocks and closure of the haplochromine trawl fishery) all have merit, the changes that are occurring in Lake Victoria are basically irreversible. The highest priority should be to assist the governments of the riparian countries (Tanzania, Uganda and Kenya) with monitoring and research programmes and to support their policies of non-introduction of further alien fishes into any of the African Great Lakes so as prevent the same cycle of events from occurring, for example, in Lakes Tanganyika and Malawi. The diverse animal and plant communities of the African Great Lakes are a heritage of all mankind and it is the duty of every country to play a role in their conservation. It is therefore proposed that an internationally funded research programme should be mounted on the African Great Lakes on the scale of the tropical forest biome project of the IUCN. Editorial     

Cytonuclear evidence for hybridogenetic reproduction in natural populations of the Australian carp gudgeon (Hypseleotris: Eleotridae)

Although most vertebrates reproduce sexually, a small number of fishes, amphibians and reptiles are known in which reproduction is asexual, i.e. without meiotic recombination. In fishes, these so-called unisexual lineages usually comprise only females and utilize co-occurring males of a related sexual species to reproduce via gynogenesis or hybridogenesis. Here, we examine patterns of microsatellite and mitochondrial DNA (mtDNA) variation in a widespread group of freshwater fishes (carp gudgeons; Hypseleotris spp.) to investigate a long-standing proposal that this group includes unisexual forms. We show that the mtDNA genome of most carp gudgeons in tributaries of the Goulburn River belongs to one of two deeply divided clades (～10% cyt b divergence) and that nuclear variation divides the same individuals into four distinct groups. Group 1 exhibits the genotypic proportions of a random mating population and has a 1:1 sex ratio. Two other groups are extremely sex-biased (98% male, 96% female), exhibit excess heterozygosity at most loci and share at least one allele per locus with group 1. We propose that these two groups represent 'unisexual' hybridogenetic lineages and that both utilize co-occurring group 1 as sexual host. Interestingly, the fourth distinct group appears to represent hybrid offspring of the two putative hybridogenetic lineages. The propagation of clonal haploid genomes by both males and females and the ability of these clones to unite and form sexually mature diploid hybrid offspring may represent a novel mechanism that contributes to the dynamics of coexistence between hybridogenetic lineages and their sexual hosts.     

Encephalization in Gobioidei (Teleostei)

We have measured the brain and body weight and determined the encephalization index for 180 species of fishes belonging to six families of the suborder Gobioidei. Within the Teleostei, these fishes exhibit a remarkably broad range in the values of their encephalization indices, but most values are in the low to middle range. Within the Gobioidei there is relatively little difference in the degree of encephalization among the different families and subfamilies except the Kraemeriidae and Amblyopinae which have low encephalization indices and the Oxudercinae (including Periophthalmus) and Rhyacichthyidae which are highly encephalized. We have shown that the form of the body has an effect on the degree of encephalization. Elongate fishes have low values, probably because of the excessive mass of their body skeleton which raises the body weight relative to the brain size. The environment in which the fishes live is correlated, in general, with their relative brain size. The values of the encephalization index arranged from low to high by habitat are as follows: muddwelling fishes, freshwater fishes, brackishwater fishes, burrowing marine fishes, freeliving marine fishes, torrent fishes and amphibious fishes. The low values of the Amblyopinae and Kraemeriidae can be explained in terms of their being both mud-dwelling and elongate.     

Close encounters with eddies: oceanographic features increase growth of larval reef fishes during their journey to the reef

Like most benthic marine organisms, coral reef fishes produce larvae that traverse open ocean waters before settling and metamorphosing into juveniles. Where larvae are transported and how they survive is a central question in marine and fisheries ecology. While there is increasing success in modelling potential larval trajectories, our knowledge of the physical and biological processes contributing to larval survivorship during dispersal remains relatively poor. Mesoscale eddies (MEs) are ubiquitous throughout the world''s oceans and their propagation is often accompanied by upwelling and increased productivity. Enhanced production suggests that eddies may serve as important habitat for the larval stages of marine organisms, yet there is a lack of empirical data on the growth rates of larvae associated with these eddies. During three cruises in the Straits of Florida, we sampled larval fishes inside and outside five cyclonic MEs. Otolith microstructure analysis revealed that four of five species of reef fish examined had consistently faster growth inside these eddies. Because increased larval growth often leads to higher survivorship, larvae that encounter MEs during transit are more likely to contribute to reef populations. Successful dispersal in oligotrophic waters may rely on larval encounter with such oceanographic features.     

Psychological and social well-being of bony fishes in zoos and aquariums

Research on the behavior of animals in zoos has been conducted for decades and observations have provided information that has improved the psychological and social well-being of animals. However, research on fishes in zoos and aquariums seems to be lacking. Here we assess the current state of research on fishes in zoos and aquariums by surveying peer-reviewed literature. Our assessment differs from previous surveys in that we examine the taxonomic classes Chondrichthyes (sharks and rays) and Osteichthyes (bony fishes) separately. Our survey finds that bony fishes have been drastically underrepresented in zoo journals, more so than chondrichthyans, revealing an urgent need for zoos and aquariums to conduct research on the behavior of the bony fishes in their care, to ensure a positive state of psychological and social well-being. To plot a course for the future, we discuss the few studies that have been conducted on the behavior of bony fishes in zoos and aquariums, and we discuss research conducted on bony fishes in food-fish aquaculture and biomedicine to identify the types of studies that could be conducted in zoos and aquariums. We conclude that data-driven analyses of fish behavior could aid in development of evidence-based practices that enhance the well-being of bony fishes in zoos and aquariums, just as they already do for terrestrial animals.