Regional features of alien macroinvertebrate invasion into the water ecosystems of the Ob River basin

The peculiarities of invasion of alien macroinvertebrates into the water bodies of the Ob river basin have been studied. It has been noted that the construction of hydropower plants and fishery management play the key role in the invasion of alien fauna. The main invasion corridors and the tendencies of long-term alterations in them have been revealed. The common and distinctive features of the alien fauna of the Ob River basin and the invasive species of large European rivers have been determined. It is shown that a considerable number of alien invertebrates have been introduced into the Ob river accidentally.     

Range expansion of rotan <Emphasis Type="Italic">Perccottus glenii</Emphasis>, sunbleak <Emphasis Type="Italic">Leucaspius delineatus</Emphasis>, and bleak <Emphasis Type="Italic">Alburnus alburnus</Emphasis> in the Ob River basin

The ranges of three alien fish species (rotan Perccottus glenii, sunbleak Leucaspius delineatus, and bleak Alburnus alburnus) in the Ob River basin, West Siberia, have expanded. Our data prove the expansion of rotan and sunbleak ranges to the north. In particular, for the first time, populations of rotan are reported from the lower section of the Ob. We also present new data about range expansion of the studied fish species southward. All three species have probably reached the southern limits of their possible distribution in the Upper Ob system, entering the potamon/rhithron transition zone, because the species under study prefer lowland waters. The spatio-temporal dynamics of their expansion reveals the role of the Ob River as the main invasion corridor, enhancing their distribution mostly in meridional direction. In the system of the Upper Ob, rotan and sunbleak were found by us in isolated ponds and lakes, as well as in floodplain systems. This is in agreement with the concept of two invasion vectors: the translocation of fish by humans between water bodies and self-distribution along the river courses.     

广东省主要水系外来水生动物初步调查

【背景】广东省是我国遭受外来生物入侵最严重的地区之一,许多外来水生动物在广东省的河流均有分布,但有关其具体分布和数量缺乏系统研究。【方法】通过野外调查的方式对广东省鉴江、韩江、潭江、西江、北江、东江等水系的外来水生动物的分布和数量进行了初步调查,并对调查到的外来水生动物的生态学特征和入侵机制进行了初步研究。【结果】共调查到13种外来水生动物,包括巴西龟、尼罗罗非鱼、莫桑比克罗非鱼、奥利亚罗非鱼、下口鲶、革胡子鲶、食蚊鱼、麦瑞加拉鲮、露斯塔野鲮、斑点叉尾鮰、大口黑鲈等11种脊椎动物和福寿螺、克氏原螯虾2种无脊椎动物;其中以福寿螺、巴西龟和3种罗非鱼的分布最为广泛。【结论与意义】几种外来水生生物主要通过水产养殖、观赏渔业和生物防治引种入侵;典型的"R"策略者、对环境具有较强耐受力的生物、杂食性鱼类更容易成功入侵。     

The status and causes of alien species invasion in China

Data of classification, origin, pathway and environmental impacts of invasive alien micro-organisms, invertebrates, amphibians and reptiles, fish, birds, mammals, weeds, trees, and marine organisms in terrestrial, aquatic and marine ecosystems of China, were analyzed, based on literature retrieval, field survey and consultation. Some 283 invasive alien species were recorded in China, including 19 invasive alien micro-organisms, 18 aquatic plants, 170 terrestrial plants, 25 aquatic invertebrates, 33 terrestrial invertebrates, 3 amphibians and reptiles, 10 fish, and 5 mammals. Of the invasive alien species, 55.1% originated from North and South America, 21.7% from Europe, 9.9% from Asia, 8.1% from Africa and 0.6% from Oceania. Many institutions and individuals in China lack adequate knowledge of ecological and environmental consequences caused by invasive alien species, with some ignorance of the dangerous invasion in the introduction of alien species. For instance, 50.0% of invasive alien plants were intentionally introduced as pasture, feedingstuff, ornamental plants, textile plants, medicinal plants, vegetables, or lawn plants, 25% of alien invasive animals were intentionally introduced for cultivation, ornament, or biological control, In addition, more efforts are being made in the introduction of alien species, and little attention is paid on the management of introduced alien species, which may cause their escape into natural environment and potential threats to the environment. There were also gaps in quarantine system in China. All microorganisms were unintentionally introduced, through timber, seedling, flowerpot, or soil; 76.3% of alien invasive animals invaded through commodity or transportation facility because of the failure of quarantine. Therefore, quarantine measures should be strictly implemented; and meanwhile the intentional introduction of alien species should be strictly managed and a system of risk assessment should be implemented.     

中国外来入侵物种的分布与传入路径分析

外来物种入侵已成为全球性的环境问题,本文采用文献调研,实地考察与专家咨询相结合的方式,调查了全国陆生,淡水水生生态系统中外来入侵微生物,无脊椎动物,两栖爬行类,鱼类,鸟类,哺乳类,杂草,树木和海洋生态系统中外来入侵物种的种类及分类地位,起源,引入路径和环境影响等内容。查明我国共有283种外来入侵物种,其中外来入侵微生物,水生植物,陆生植物,水生无脊椎动物,陆生无脊椎动物,两栖爬行类,鱼类,哺乳类分别为19种,18种,170种,25种,33种,3种,10种和5种,来源于美洲,欧洲,亚洲,非洲,大洋洲的外来入侵物种分别占55.1%,21.7%,9.9%.8.1%和0.6%。我国对外来物种的引进存在一定程度的盲目性;50.%的外来入侵植物是作为牧草或饲料,观赏植物,纤维植物,药用植物,蔬菜,草坪模特而引进的;25%的外来入侵动物是用于养殖,观赏,生物防治的引种,对外来物种只重引进,疏于管理,也可能导致外来物种逃逸到自然环境中,造成潜在的环境意传入的;76.3%的外来入侵动物是由于检查不严,随贸易物品或运输工具传入我国的。因此,我国既要加强检疫工作,又要对外来物种的有意引进进行严格管理,实行外来物种引进的风险评估制度。     

Opisthorchis felineus (Rivolta, 1884) and Metorchis bilis (Braun, 1890) infections in population of some regions of the Ob River Basin

The incidence of Opisthorchis felineus (Rivolta, 1884) and Metorchis bilis (Braun, 1890) infections among people living in several regions of the Ob River basin in the West Siberia has been assesed in this work. Our results suggest that Metorchis bilis infection was common in many of the serologically tested people. Moreover, this helminth was obtained from the biliary ducts of humans in autopsy.     

Popularity and Propagule Pressure: Determinants of Introduction and Establishment of Aquarium Fish

Propagule pressure is frequently cited as an important determinant of invasion success for terrestrial taxa, but its importance for aquatic species is unclear. Using data on aquarium fishes in stores and historical records of fish introduced and established in Canadian and United States waters, we show clear relationships exist between frequency of occurrence in shops and likelihood of introduction and of establishment. Introduced and established taxa are also typically larger than those available from stores, consistent with the propagule pressure hypothesis in that larger fish may be released more frequently due to outgrowing their aquaria. Attempts to reduce the numbers of introductions may be the most practical mechanism to reduce the number of new successful invasions.     

Invasive species threats to native aquatic insect biodiversity and conservation measures in Hawai’i and French Polynesia

Impacts of invasive species, and of attempts to control them, on the aquatic invertebrate fauna of Hawaii and French Polynesia are reviewed and discussed, as a foundation for determining conservation need. Aquatic insects are poorly documented in the region, with many species undescribed, so that practical conservation must be pursued with highly incomplete basic taxonomic knowledge. The establishment of at least one dedicated reserve for aquatic invertebrates is recommended for each high island in an archipelago, as an aid to safeguarding local endemic species, and other recommendations include increased monitoring for new alien species (particularly of fish), planning for removal of alien species from selected water bodies where alien species are less likely to recolonize, effective protection of key sites with high biodiversity value, and securing sites for future restoration and translocation or rare and endangered species.     

First record of the invasive snail Melanoides tuberculatus (Gastropoda: Prosobranchia: Thiaridae) in the Paran? River Basin, GO, Brazil.

The Thiarid snail Melanoides tuberculatus (Müller, 1774), native to Asia and East Africa was recorded for the first time in the Paran? River basin, Goiás State. There is no evidence concerning introduction vectors but aquarium releases is the most probable vector. Specimens were collected at three different water bodies after twenty-seven rivers were investigated. The possible spread of this species to other habitats and potential effects on native thermal water communities are discussed.     

The need for research and monitoring on the impacts of translocated sharptooth catfish,Clarias gariepinus,in South Africa

The sharptooth catfish, Clarias gariepinus (Burchell, 1822), is a widespread African freshwater fish species which occurs naturally from the Nile to the Orange River. Through translocation aquaculturists, farmers, anglers and engineers have helped to extend its range into many South African rivers where it did not occur naturally and where it is now an alien invasive species. Being a very hardy fish species it will have a major impact on a range of aquatic, amphibian and avian biota, impacts that should not be under-estimated and which urgently require study. Ironically, the illegal introduction of catfish into some dams has impacted on sport fisheries for another alien: bass. There is also a serious potential impact from alien catfish on freshwater eels. Anglers and farmers need to be educated about the adverse consequences of introducing catfish and a serious look needs to be taken at interbasin transfers of biota by engineers.     

Changes in the ranges of pasture ixodid ticks of the genus Ixodes Latr., 1795 (Parasitiformes, Ixodidae) in West Siberia

The distribution pattern of two tick species, Ixodes persulcatus and Ixodes pavlovskyi, in the plain part of West Siberia is analyzed. The exact northern range boundary of I. persulcatus in the Khanty-Mansi Autonomous Area is determined based on long-term data on the population density of adult and immature ticks (1960–2011). The shift of the southern boundary of the species range in West Siberia as related to anthropogenic transformation (reforestation measures, reduced or stopped sanitary forest cutting, road construction, etc.) is demonstrated. The specific traits of distribution of the taiga tick I. persulcatus in some localities of Southwest Siberia are analyzed. The modern state of the tick population in the areas co-inhabited by the two species is characterized. The possible reasons of changes in the structure of tick communities toward complete prevalence of I. pavlovskyi in recreational zones of Novosibirsk and Tomsk are discussed. The most significant changes in the distribution pattern of these two tick species in West Siberia seem to have occurred after 1990. During this period, the local stable populations of the taiga tick to the south of its main range in West Siberia (within Omsk and Novosibirsk provinces) were formed, the pattern of its distribution on the right bank of the Ob River (Novosibirsk Province) and in the Tom River valley (Tomsk Province) changed, whereas I. pavlovskyi became the dominant species.     

Genetic Analysis of Betanodaviruses in Subclinically Infected Aquarium Fish and Invertebrates

Betanodaviruses causing viral nervous necrosis (VNN) have been detected and isolated from several species of cultured marine fish worldwide. In Korea, VNN was identified in several species of cultured marine fish. This study presents data on the amplified nested PCR product (420 bp) of 11 nodavirus strains from different species of apparently healthy aquarium fish and invertebrates collected in one private commercial aquarium in Korea. Phylogenetic analyses based on the partial nucleotide sequence (177 bases) of the RNA2 coat protein gene were identical to the redspotted grouper nervous necrosis virus (RGNNV) genotype (96%–100%). The presence of the RGNNV type of betanodaviruses in these subclinically infected aquarium fish and invertebrates imported from different countries probably indicates that the samples were contaminated inside the aquarium and represents a serious challenge for its management of viral nervous necrosis. These positive samples can be an inoculum source of betanodavirus infection to other susceptible fish species inside the aquarium.     

柳江鱼类群落结构及多样性研究

为了解柳江鱼类群落结构、多样性及其与环境因子的关系, 2018年7月和12月在柳江9个江段(榕江、从江、融安、柳城、象州、永福、鹿寨、河池和宜州)开展鱼类和环境调查。共采集鱼类36474尾, 隶属于5目20科80属115种; 其中, 鲤科鱼类最多(68种), 占59.13%。Shannon-Wiener多样性指数、Simpson指数、Pielou均匀度指数和Margalef丰富度指数的变化范围分别为2.13—3.12、0.81—0.93、0.58—0.80和4.65—7.18。鱼类优势种以银Squalidus argentatus、大眼华鳊Sinibrama macrops、胡Microphysogobio chenhsienensis、银鲴Xenocypris macrolepis和南方拟?Pseudohemiculter dispar等小型鱼类为主。丰度/生物量比较曲线表明, 宜州、榕江、鹿寨、柳城、象州和融安江段鱼类群落受到中度或严重干扰, 河池、从江和永福鱼类群落结构相对稳定。采用非度量多维标度排序(NMDS)方法对鱼类群落的时空分布特征进行分析, 将鱼类划分为3个类群: 柳江上游的从江-榕江类群, 洛清江支流的永福-鹿寨类群, 柳江中下游及龙江支流的融安-柳城-象州-河池-宜州类群。采用典范对应分析(CCA)分析鱼类群落与环境因子的关系, 发现河宽、海拔和pH是柳江鱼类群落结构差异的主要影响因子。与历史资料相比, 柳江鱼类群落结构发生显著变化, 经济鱼类占比减少, 鱼类个体呈现小型化和低龄化。建议从以下几个方面加强柳江鱼类多样性保护: 加强执法力度, 严厉打击偷捕、电捕等非法行为; 对主要经济鱼类开展增殖放流; 恢复河流的连通性; 对流域珍稀特有鱼类进行监测、救护和繁育。     

Threat of non-native crayfish introductions into Turkey: global lessons

Introductions of crayfish species from their home range to new environments have been carried out in many parts of the world. The most important introduced crayfish species are Procambarus clarkii, Pacifastacus leniusculus, Cherax destructor, C. quadricarinatus, Orconectes limosus, O. rusticus and Astacus leptodactylus. The environmental impact of crayfish introductions can be positive, negative or neutral. However, native crayfish populations in Europe have been negatively affected by introductions of non-indigenous crayfish species from America. Negative effects of non-native crayfish introductions included displacement of native crayfish species, transfer of disease (crayfish plague), consumption of fish eggs, reduction of fish stocks, consumption of large amounts of macrophytes, indirect and direct effects on other invertebrates and upsetting production in rice fields. As a result of non-native crayfish introductions, the natural harvest and crayfish industry in Europe have been severely affected. Large quantities of Turkish A. leptodactylus were harvested (approximately 7,000 tonnes annually) and exported to Europe before the crayfish plague was observed in these populations. The total harvest of A. leptodactylus in Turkey reduced dramatically to 320 in 1991 after the plague. Therefore, although Turkey currently has no known non-native crayfish species, there is a threat of non-native crayfish introduction in order to increase crayfish productions and subsequent harvest. The North American spiny-cheek crayfish, O. limosus, has been spreading quickly down the River Danube and could soon reach neighboring countries including Turkey. The North American signal crayfish, P. leniusculus is known from Greece and could be a threat to native stocks if it is introduced into Turkey for aquaculture. Additional threats may come from the release of other North American species, which are widely available through the aquarium trade. We conclude that the spread of non-native crayfish introductions throughout Turkey will increase local problems, because introductions of non-native crayfish in many parts of the world have been known to have caused important reductions in population density and numbers of native crayfish species. Furthermore, freshwater ecosystems may be altered by such introductions and the economic viability of native crayfish species fisheries could be severely reduced in Turkey.     

A risk assessment of aquarium trade introductions of seaweed in European waters

Aquaculture and maritime traffic have been identified as the main vectors for introductions of alien marine species. Except for one notorious case of Caulerpa taxifolia, the role of aquarium trade towards the introduction of alien seaweeds has been largely unassessed. Here, we address the risk of accidental release of seaweed species from the aquarium trade market in European waters. We assessed the importance and diversity of seaweed species in the European online aquarium retail circuit. Our web survey revealed more than 30 genera available for online sale into Europe, including known introduced and invasive species. A second aspect of the study consisted in sampling algal diversity found in aquaria. While allowing direct and accurate identification of the specimens, this approach was targeting not only ornamental species, but also seaweeds that may be accidentally present in the aquarium circuit. By DNA-barcoding we identified no less than 134 taxa, 7 of which are flagged as introduced in Europe and 5 reported as invasive. Climate envelope models show that at least 23 aquarium species have the potential to thrive in European waters. As expected by the tropical conditions in most aquaria, southern Atlantic regions of Europe and the Mediterranean are the most vulnerable towards new introductions. Further predictions show that this risk will increase and shift northwards as global warming proceeds. Overall our data indicate that aquarium trade poses a potential risk of new seaweed introductions, and calls for a cautious approach.     

Are alien fish a reliable indicator of river health?

1. The ability of many introduced fish species to thrive in degraded aquatic habitats and their potential to impact on aquatic ecosystem structure and function suggest that introduced fish may represent both a symptom and a cause of decline in river health and the integrity of native aquatic communities. 2. The varying sensitivities of many commonly introduced fish species to degraded stream conditions, the mechanism and reason for their introduction and the differential susceptibility of local stream habitats to invasion because of the environmental and biological characteristics of the receiving water body, are all confounding factors that may obscure the interpretation of patterns of introduced fish species distribution and abundance and therefore their reliability as indicators of river health. 3. In the present study, we address the question of whether alien fish (i.e. those species introduced from other countries) are a reliable indicator of the health of streams and rivers in south‐eastern Queensland, Australia. We examine the relationships of alien fish species distributions and indices of abundance and biomass with the natural environmental features, the biotic characteristics of the local native fish assemblages and indicators of anthropogenic disturbance at a large number of sites subject to varying sources and intensities of human impact. 4. Alien fish species were found to be widespread and often abundant in south‐eastern Queensland rivers and streams, and the five species collected were considered to be relatively tolerant to river degradation, making them good candidate indicators of river health. Variation in alien species indices was unrelated to the size of the study sites, the sampling effort expended or natural environmental gradients. The biological resistance of the native fish fauna was not concluded to be an important factor mediating invasion success by alien species. Variation in alien fish indices was, however, strongly related to indicators of disturbance intensity describing local in‐stream habitat and riparian degradation, water quality and surrounding land use, particularly the amount of urban development in the catchment. 5. Potential confounding factors that may influence the likelihood of introduction and successful establishment of an alien species and the implications of these factors for river bioassessment are discussed. We conclude that the potentially strong impact that many alien fish species can have on the biological integrity of natural aquatic ecosystems, together with their potential to be used as an initial basis to find out other forms of human disturbance impacts, suggest that some alien species (particularly species from the family Poeciliidae) can represent a reliable ‘first cut’ indicator of river health.     

Taxonomic diversity of parasites in agnathans and fishes from the Volga River basin v. Nematoda and Gordiacea

The checklist of Nematoda and Gordiacea parasitizing agnathans and fishes in the Volga River basin is presented. Hosts and areas of distribution are indicated for each parasite species. The checklist includes 39 species and 11 nonidentified larval forms of nematodes from 51 fish species. Larvae of Gordius sp. are found in 5 fish species. The nemadote species Sinoichthyonema amuri have been introduced into the Volga basin occasionally during the process on introduction of fish species from Amur River.     

How do invasive species travel to and through urban environments?

Globalisation has resulted in the movement of organisms outside their natural range, often with negative ecological and economic consequences. As cities are hubs of anthropogenic activities, with both highly transformed and disturbed environments, these areas are often the first point of entry for alien species. We compiled a global database of cities with more than one million inhabitants that data had on alien species occurrence. We then identified the most prominent pathways of introduction and vectors of spread of alien species in these cities. Most species were intentionally introduced to cities and were released or escaped from confinement. The majority of alien species then spread within cities through natural means (primarily unaided dispersal). Pathway prominence varied across the taxonomic groups of alien species: the most prominent pathway for plants and vertebrates was the escape pathway; for invertebrates the stowaway and contaminant pathways were most likely to facilitate introductions. For some organisms, pathway prominence varied with the geographical and climatic characteristics of the city. The characteristics of the cities also influenced the prominence of vectors of spread for alien species. Preventing the natural spread of alien species within cities, and into adjacent natural environments will be, at best, difficult. To prevent invasions, both the intentional and unintentional introduction of potentially harmful alien species to cities must be prevented. The pathways of introduction and vectors of spread identified here should be prioritised for management.     

塔里木盆地鱼类入侵及区系演变趋势

鱼类入侵是塔里木盆地土著鱼类濒危的关键性影响因素之一,结合历史文献数据及近年调查数据,系统综述了塔里木盆地鱼类入侵现状,并就鱼类入侵引起的鱼类区系均一化问题进行了分析。结果显示,该地区记录鱼类63种,其中土著种19种,入侵种44种。尽管入侵鱼类提升了塔里木盆地鱼类群落属级及科级的多样性水平,但相应的G-F多样性指数却明显下降,表明该区鱼类群落从物种组成简单、分化明显的特点演变为物种成分复杂、分化贫乏的特点。入侵种中源于长江和额尔齐斯河分别有30种(68.2%)和7种(15.9%),源于美欧和亚洲其他区域的有7种(15.9%)。入侵鱼类的进入引起塔里木盆地与其相关区域鱼类区系相似性显著上升(P0.01),并导致该区鱼类区系从单一的中亚高原山区复合体演变为多区系混合体。进一步利用鱼类个体生态矩阵分析方法研究显示,外来种在塔里木盆地适应性广泛,能够占据水域各种栖息生境,显著压缩了土著种的栖息空间,进而通过捕食、食物竞争及其他作用途径严重危及土著鱼类种群的续存,提示须采取有力措施限制入侵种的进一步扩散及对濒危土著物种迅速开展人工保育工作。