Introduction Of Exotic Fishes Research Articles

The macroparasite fauna of cichlid fish from Nicaraguan lakes, a model system for understanding host\u2013parasite diversification and speciation

The Nicaraguan lakes represent an ideal continent-island-like setting to study the colonization patterns of both fish and their parasites. The dominant fish fauna are cichlids, particularly the Midas cichlid species complex Amphilophus spp., a well-studied model for recent sympatric speciation. Here, we characterized the Midas cichlid macroparasite diversity in Nicaraguan lakes. We evaluated patterns of parasite diversity across host populations. Morphological and molecular analyses were conducted, revealing a macroparasite fauna composed by 37 taxa, including platyhelminths, nematodes, copepods, branchiurans, hirudineans and oribatids. Three invasive species are reported for the first time. The Midas cichlid was infected by 22 parasite taxa, 18 shared with other cichlids. Eight taxa conformed the core parasite fauna of the Midas cichlid. The large lakes had higher parasite diversity than the smaller and isolated crater lakes, although parasite infracommunity diversity was lower. Environmental factors along with the differential distribution of intermediate hosts, the potential resistance gained by their hosts after colonization of new lakes, competitive exclusion among parasites, or the introduction of exotic fish, may determine the observed pattern of parasite heterogeneous distribution. Our study provides a ground to explore the evolutionary history of both, hosts and parasites within the context of speciation and diversification processes.

Fish fauna of Uttarakhand, India: Present status, Diversity and Conservation

Extensive Ichthyofaunal survey of various water resources of Uttarkhand was carried out for the period of more than 15 years (2004-2019). The main objective of this paper is to know the district wise status, distribution and to recommend the strategy for the conservation and management of fishes of the state, so that clear-cut idea could be drawn, for further research and policy planning. In the present paper a total of 132 species of fish belonging to 67 genera, 27 families and 8 orders have been reported. The district wise distribution of fish represented a maximum of 101 species from Nainital, followed by 81 species from Dehradun, 75 species from Haridwar, 73 species from Udham Singh Nagar, 59 species from Pauri Garhwal, 37 species from Rudrapryag, 36 species from Almora, 35 species from Chamoli, 34 species from Bageshwar, while 32 species from Pithoragarh and Champawat and 29 species each from Uttarkashi and Tehri Garhwal. Besides these 10 species (7.5%) are in the category of Endangered, while 10 species (7.5%) are exotic in nature and 11 species (8.3%) are endemic to the Uttarakhand state. On the basis of fish catch the dominant species in upper region (hill area) are Schizothoracine species (which forms appox. 60% of fish catch) and in the plains dominant species are Barilius species (which forms 40% of fish catch) etc. Besides this after the careful observation and constant monitoring, some major factors responsible for the depletion of fish resources were listed out which include over exploitation of fish resources, lack of fish policy/laws, deforestation, destruction of spawning ground, shrinkage of water bodies, pollution/weed infestation in water bodies, introduction of exotic fish, construction of dams (which effect fish migration) and lack of awareness among masses. Moreover, the conservation and management strategy for fish has also been discussed in detail.

Externalidades ambientales y resiliencia lacustre en la Ciénega de Chignahuapan, México

Este estudio analiza los conflictos que producen los modos de apropiación de los recursos naturales y las externalidades ambientales que alteran las funciones ecosistémicas de la Ciénega de Chignahuapan o Atarasquillo. Se utilizó literatura, documentos oficiales, estadísticas y cartografía, la observación in situ y la información oral de los actores sustenta la base empírica de la investigación. Las externalidades regionales que amenazan la estabilidad del cuerpo lacustre expresan cambios de uso de suelo, disminución de los servicios hídricos del bosque, contaminación de afluentes, construcción de vialidades regionales, actividad industrial, re densificación demográfica, urbanización y sub urbanización. Las externalidades locales manifiestan alteración del régimen hidrológico, quemas de tule, introducción de peces exóticos, contaminación por descargas residuales crudas, proliferación de malezas terrestre y acuática, transferencia de los derechos de la actividad cinegética y aprovechamiento de subsistencia de los recursos lacustres. La presión exhibe un escenario desalentador que anticipa descenso de la capacidad natural del ecosistema lentico para superar las externalidades negativas. La visión sostenible prescribe estrategias de colaboración, autogestión y regulación, con el objeto de que las industrias acaten la responsabilidad ambiental para tratar y conservar el agua; los gobiernos incrementen la capacidad de tratamiento de aguas residuales y los usuarios mejoren el uso y cuidado del recurso. En las unidades de manejo monitorear el cumplimiento de la conservación, aplicar la ley en materia cinegética y prácticas ilegales, regular el arrendamiento cinegético por terceros, recuperar el conocimiento tradicional y desarrollar proyectos alternativos que moderen el uso de los recursos lacustres.Palabras clave: Externalidades, resiliencia, Ciénega, apropiación, recursos naturales.

An island invaded by exotics: a review of freshwater fish in Puerto Rico

ABSTRACT The introduction of exotic fishes in streams and water reservoirs has modified autochthonous freshwater fish communities in Puerto Rico. There are approximately 46 fish species in inland waters, and most of them were introduced during the last century. We here summarize relevant information on 46 freshwater fish species reported for the island. Approximately 80% of the species are non-native. An evaluation of the local trade revealed another 128 freshwater fish species are sold locally as pets. This raises serious concerns, as we detected a potential pool of non-native species that are either considered invasive elsewhere, or that, based on their ecology, could become invasive on the island in the near future. We also found that cichlids as a group pose the highest risk to freshwater ecosystems, with 13 species established in the wild, and another 38 potential invaders in the local pet trade. This study may be used as a baseline for the conservation and management purposes of both native and non-native fish species, including the development of strategies for preventing the release of live fish pets into the wild. More specific management for non-native fish, especially those identified here that pose significant threats to Puerto Rico’s native fish and their ecosystems, are warranted.

Cosmopolitanism vs. Statism: Issues with Modern Ethical Distribution Models and their Impact on Interplanetary Relations

The introduction of exotic fish has been detrimental to wetland ecosystems, thus making it important to understand their distributions in respect to roadway corridors in the South Florida region. We sampled fish with modified minnow traps at 18 study sites within three different landscape (urban, herbaceous marsh, forested marsh) and habitat type features (storm water ponds and canals) in order to determine the relative abundance of exotic fish. Our results suggest that exotic fish do have a higher relative abundance and proportion of biomass in the urban landscape, the canal habitat feature type, and the urban canal feature. Understanding patterns of exotic fish biomass and relative abundance in roadway corridor features could be useful for future management of these species in the South Florida region.

Stocking activities for the Arctic charr in Lake Geneva: Genetic effects in space and time.

Artificial stocking practices are widely used by resource managers worldwide, in order to sustain fish populations exploited by both recreational and commercial activities, but their benefits are controversial. Former practices involved exotic strains, although current programs rather consider artificial breeding of local fishes (supportive breeding). Understanding the complex genetic effects of these management strategies is an important challenge with economic and conservation implications, especially in the context of population declines. In this study, we focus on the declining Arctic charr (Salvelinus alpinus) population from Lake Geneva (Switzerland and France), which has initially been restocked with allochtonous fishes in the early eighties, followed by supportive breeding. In this context, we conducted a genetic survey to document the evolution of the genetic diversity and structure throughout the last 50 years, before and after the initiation of hatchery supplementation, using contemporary and historical samples. We show that the introduction of exotic fishes was associated with a genetic bottleneck in the 1980–1990s, a break of Hardy–Weinberg Equilibrium (HWE), a reduction in genetic diversity, an increase in genetic structure among spawning sites, and a change in their genetic composition. Together with better environmental conditions, three decades of subsequent supportive breeding using local fishes allowed to re‐establish HWE and the initial levels of genetic variation. However, current spawning sites have not fully recovered their original genetic composition and were extensively homogenized across the lake. Our study demonstrates the drastic genetic consequences of different restocking tactics in a comprehensive spatiotemporal framework and suggests that genetic alteration by nonlocal stocking may be partly reversible through supportive breeding. We recommend that conservation‐based programs consider local diversity and implement adequate protocols to limit the genetic homogenization of this Arctic charr population.

The dire implications of releasing marine ornamental fishes into the wild: first reported case from the Red Sea

This study provides the first documented incidence of aquarium-based introduction of exotic fishes into the Red Sea, in the Coral Beach Nature Reserve in Eilat, Israel. A clown triggerfish Balistoides conspicillum and a queen angelfish Holacanthus ciliaris were sighted inside the marine protected area, then captured and examined, and Photobacterium damselae ssp. piscicida was isolated from the kidney of H. ciliaris. This is the causative agent of “fish pasteurellosis”, which has been responsible for massive kills in natural fish populations. The finding of this pathogen in the angelfish is worrisome, and exemplifies the concerns associated with the introduction of non-indigenous fish together with unwanted pathogens. Our findings underscore the vital importance of raising public awareness against such practices in order to curb future ecological impairment of this biologically fragile natural habitat.

Impact of the historical introduction of exotic fishes on the chironomid community of Lake Azul (Azores Islands)

Little is known about the effect of top predator introduction in historically fishless communities, especially on remote islands. This issue is important because it might strongly affect climate reconstructions derived from biota assemblages such as chironomids. Head capsule larval remains of chironomids have been studied in a 660years lacustrine sedimentary sequence from Lake Azul (Sao Miguel Island, Azores archipelago) to assess the extent and timescale of the effect of the predator introduction occurring in this historically fishless lake. Analysis of similarity showed that the chironomid assemblage was statistically different before and after predator introduction (R=0.78; p<0.001). Abundance of chironomids was about 40% greater in the fishless lake period compared to the period in the presence of predator. Results show major change in chironomid assemblage coinciding with the first time of goldfish introduction (around 1790CE), followed by carp (1890CE) and pike (1979CE) introductions. The composition of feeding group guilds changed following a pattern characterized by a decrease in abundance of detritivorous and predaceous taxa and an increase in abundance of grazing chironomid taxa. This study suggests that predator introduction was the most important factor affecting the chironomid assemblages in this natural, Azorean fishless lake, but predators did not affect all chironomid species. Other external forcings like major climate oscillations, anthropogenic activities in the catchment basin, and volcanic eruptions seem to play an additional role. The latest stage of the warm and arid Medieval Climate Anomaly (1000–1300CE) favoured the occurrence of some warm-adapted chironomid taxa, which were absent through the Little Ice Age (ca. 1450–1850CE) cool period.

Occurrence of Ornamental Fishes:A Looming Danger for Inland Fish Diversity of India

India is known for its immense aquatic wealth, in particular freshwater fish resource. But, the ongoing ornamental fish trade and introduction of exotic fishes in the wild pose a serious threat to India's native aquatic diversity. Recent studies from several parts of India have revealed the presence of several ornamental fishes in inland water bodies, including the biologically sensitive areas such as Chalakudy River in the Western Ghats, a biodiversity hot spot which harbours 16 endangered and 4 critically endangered species. So far, 27 ornamental species have been reported in the inland wetlands of India. Among them, 15 have already established a good breeding population and have emerged as a threat to the native species. Awareness among the public, policy makers and researchers about the impacts of ornamental fishes in inland water is the need of the hour. Stringent measures should be taken to monitor the aquarium fish trade and accidental release of exotic species into inland waters. If not, the invasion of ornamental fishes may demolish the inland aquatic diversity of native Indian breeds.

The long-term effects of bottom-up and top-down forcing on zooplankton: An example from sedimentary bosminid records of Lake Dianchi and Lake Fuxian

近年来云南高原湖泊面临富营养化、渔业活动增强等多重环境压力的叠加影响,对湖泊的有效治理与生态修复急需对多重压力下生态系统的响应模式进行系统了解.现有研究表明在系统生产力和捕食压力的不同配置下,湖泊系统主要组成(如浮游动物)的响应特征可能出现差异且捕食压力可能随营养水平的变化而改变,目前对云南湖泊生态系统的研究主要集中于单一环境压力下的生态响应.本研究以目前分别处于重富营养和中-贫营养水平的滇池和抚仙湖为研究对象,应用湖泊沉积物记录进行多指标分析,探讨受外来鱼类影响下两个大型湖泊浮游动物长期响应模式的异同.通过象鼻溞生物量与个体大小等指标,重建了近百年来滇池与抚仙湖典型浮游动物的变化历史,结果表明随着湖泊生产力水平(如沉积物色素生产量)的增加,2个湖泊中象鼻溞生物量显著增加,同时物种相对组成出现明显变化(如Bosmina longispina被B.longirostris取代),指示湖泊上行效应对浮游动物的控制作用.同时象鼻溞的生物量、壳长与触角长度的变化在1960s与1980s有明显降低的趋势,与同期外来鱼类(如银鱼)引入与渔业产量增加的时间一致.进一步应用多变量回归分析与方差分解方法来定量评价上行与下行效应对象鼻溞生物量变化的驱动强度,结果表明富营养化(沉积物色素)和捕食作用(象鼻溞壳长)对浮游动物长期变化的驱动强度比较相似(分别解释了生物量变化的77.25%和83.59%),然而在滇池下行效应对象鼻溞生物量的独立影响比在贫营养的抚仙湖中更强(分别为15.46%和10.39%),上行效应对象鼻溞生物量的影响在抚仙湖要明显强于滇池(分别为69.74%和19.67%),而在滇池上行与下行效应的相互作用强度明显强于抚仙湖(分别为42.12%和3.46%).结果表明随着湖泊营养水平的升高,浮游动物的生物量在2个湖泊中均显著增加,而外来鱼类(如太湖新银鱼)的引入和经济鱼类数量的增加加剧了对浮游动物的捕食压力,造成了浮游动物的生物量降低和个体减小.但在快速富营养化的滇池,对浮游动物的捕食压力随营养水平的变化出现较强的依赖性,而在总体处于中-贫营养水平的抚仙湖中此相互作用较弱.结果表明在不同营养水平的大型湖泊中,营养水平的变化幅度可以导致鱼类捕食压力的差异性变化,指示了对鱼类捕食压力的评价和浮游动物长期变化的特征分析需要考虑湖泊的营养水平与富营养化过程的差异.总之,富营养化和外来鱼类的引入导致了高原湖泊生态系统的快速响应与结构变化,因此对高原湖泊的生态修复需要考虑湖泊营养水平对生态系统结构与食物链作用的影响.;In recent years, lakes of Yunnan Plateau have increasingly experienced the pressure of multiple environmental stressors like eutrophication and fish invasion, as well as their synergic effects. To date, most studies have focused on the ecological impacts of a single stressor, in spite of the interaction of these multiple stressors. This paper selected Lake Dianchi and Lake Fuxian, which are currently hypo-eutrophic and oligo-mesotrophic respectively, and conducted multi-proxy analyses of lake sediments from both lakes. We aim to quantify the impacts of both eutrophication (bottom-up control) and predation pressure (top-down control) in driving the long-term changes of zooplankton production, and to compare the intensity of their single forcing and interaction between both lakes. Our results showed that both lakes experienced increased primary production (i.e. the production of sedimentary pigments) since the mid-20^th century, which was consistent with the eutrophication history revealed by lake monitoring data. Concurrently, the production of zooplankton (i.e. sedimentary bosminid production) increases significantly with a general trend of the oligotrophic taxon of Bosmina longispina replaced by B. longirostris found in both lakes. However, the bosminid production and body size (i.e. carapace and antennule length), displayed a decrease during the 1960s and 1980s, when exotic fish were introduced and/or established stable populations. With the methods of multiple regression and variance partitioning, our further analyses suggested that top-down control (as indicated by bosminid carapace length) exerted stronger impact on zooplankton production at Lake Dianchi than at Lake Fuxian (15.46% and 10.39%, respectively), while Lake Fuxian displayed a much stronger control of bottom-up (represented by sedimentary pigment concentration) forcing than Dianchi (69.74% and 19.67%, respectively). In addition, we found that the interaction between bottom-up and top-down is much more significant at Lake Dianchi than the Lake Fuxian (42.12 % and 3.46 %, respectively), despite that both forcing exerted a similar degree of control on zooplankton production at Lake Dianchi (77.25%) and Lake Fuxian (83.59%). These results indicate the significant control of lake eutrophication on zooplankton production at both lakes, while the introduction of exotic fish intensify the predation pressure on zooplankton, which also showed strong dependence on the rapid increase of trophic status at the hypo-eutrophic shallow lake of Lake Dianchi. In contrast, the strength of the interaction between bottom-up and top-down control was insignificant at the oligo-mesotrophic deep lake of Fuxian. Over all, our results infered that eutrophication and fish predation have led to the significant changes of ecosystem structure and trophic interaction at both large plateau lakes. Therefore, trophic status, the history of eutrophication and lake typology should be taken into account for sustainable management and ecological restoration of the plateau lakes in Yunnan.

Estado de conservación de los peces de la familia Goodeidae (Cyprinodontiformes) en la mesa central de México

Conservation status of Goodeidae familiy fishes (Cyprinodontiformes) from the Mexican Central Plateau. To establish the conservation status and threats for Goodeidae fishes in the high plateau of Mexico, I assessed limnological descriptions, and the reduction in range and in number of localities where they are found, in 53 localities (58.8% of historically reported localities). This assessment included the comparison of current collections with historical records. A principal component analysis of limnological variables showed that most remnant Goodeid species inhabit localities characterised by low environmental degradation: few appear to have a high tolerance to environmental degradation. Overall, 65% of species suffered a reduction in number of localities where they are found. Almost all species face some conservation threat, considering the criteria and categories established by the International Union for the Conservation of Nature (IUCN). Data suggest that one species is extinct (Allotoca catarinae), one more is extinct in the wild (Skiffia francesae), eight are critically endangered (Allodontichthys hubbsi, Allotoca goslinei, Allotoca regalis, Allotoca zacapuensi, Ameca splendens, Characodon audax, Hubbsina turneri, and Zoogoneticus tequila), eleven are endangered, eight can be regarded as vulnerable, four are "near threatened" and only two appear to under "least concern". Habitat loss, introduction of exotic fish, and being species with restricted physiographic range or ecologically specialised, are the main factors leading to the threat of extinction of the Goodeidae family. Recovery actions are needed for the conservation of this fish group.

Distribution and Population Characteristics of African Jewelfish and Brown Hoplo in Modified Wetlands in South Florida

Abstract The introduction of exotic fish can have profound effects on wetland ecosystems, making it important to understand wetland vulnerability to invasion. Recently, African jewelfish (Hemichromis letourneuxi) have invaded wetlands in a hydrologically altered agricultural landscape at Archbold Biological Station in peninsular Florida. We sampled 45 wetlands using minnow traps to determine the current distribution and relative abundance of African jewelfish and brown hoplo (Hoplosternum littorale), another established exotic fish. We examined whether wetland area, depth, or distance to nearest ditch influenced the distribution or catch-per-unit-effort (CPUE) of these species. We also measured the total length and weight of 864 African jewelfish and examined gut contents to determine the body condition and diet of this newly established population. African jewelfish were found in only 22% of wetlands but were the most frequently captured vertebrate in those wetlands (mean 8.30 ± 0.81 se individuals/trap-...

The invasive potential of parasitic monogenoids (platyhelminthes) via the aquarium fish trade: an appraisal with special reference to India

AbstractAquaculture, the rearing of aquatic organisms under controlled or semi‐controlled conditions to produce organisms, mainly for food, ornamental and sporting purposes, is a fastest‐growing animal‐food‐producing sector in the world. The human‐mediated introduction of exotic fish has played an important role in the success story of aquaculture. Nonetheless, many exotic fish have been implicated in the loss of native fish biodiversity, largely through the transmission of parasites and diseases amongst others. Whilst the transmission of parasites following the introduction of exotic food fish is well documented, transfer of those carried by exotic ornamental fish has received little attention. This article provides the first summary review of the global translocation of the platyhelminthes class Monogenoidea via the aquarium fish trade to draw attention to the growing parasitological risk factors associated with this form of commerce. By examining the invasive characteristics of both aquarium fish and monogenoids, I review how the monogenoids fit into the different stages that an introduced species goes through when invading the destination environment. For this, I use a theoretical framework, synthesising published reports on the aquarium fish trade with current knowledge on monogenoids to model invasion success. Next, I provide examples of invasive monogenoids on exotic Indian aquarium fish and briefly discuss the vulnerability of India to colonisation by imported aquarium fish and their parasitic monogenoids. I conclude that the aquarium fish trade is a perfect gateway for worldwide translocation of monogenoids. As this trade continues to increase and intensify, global translocation of monogenoids will expand even further.

May we eat biodiversity? How to solve the impasse of conservation and exploitation of biodiversity and fishery resources

Some of the characteristics of the African Great Lakes are the numerous species of fish, crustaceans, mollusks, plankton, and other phyla, most of them endemic. The usual sources of perturbation when speaking about Great Lakes also have their impacts on the African Great Lakes, such as overfishing, dumping of untreated sewage, pebble and sand mining, agricultural run-off and other threats. Should this biodiversity be protected in times of sheer poverty of the riparian populations? Should it be exposed to exploitation for food security? What are the values of these endemic species in economic terms? This article reviews the impacts on biodiversity by human-induced factors like exotic fish introductions and the invasive water hyacinth, but also by indirect factors like climate change. Lake Victoria has a long history of fish introductions and invasive weeds, but on Lake Tanganyika the original species composition of many taxa can still be preserved and protected, at a cost. The Great Lakes surrounding these countries, by means of conventions and regional management bodies, sought to protect the environments and called for international collaboration to improve management of the natural resources, both terrestrial and aquatic. The way forward will be to involve local fishing communities in nature conservation and management, but there are many communities and many fishermen. How to reach them in areas where there is no municipal electricity supply, no portable phone network, nor internet facilities. In the 21st century, around the African Great Lakes the keyword is survival, not only of biodiversity, but also of the inhabitants of their basins.

Perceptions of environmental changes and Lethargic crab disease among crab harvesters in a Brazilian coastal community

BackgroundLethargic Crab Disease (LCD) has caused significant mortalities in the population of Ucides cordatus crabs in the Mucuri estuary in Bahia State, Brazil, and has brought social and economic problems to many crab-harvesting communities that depend on this natural resource. The present work examined the perceptions of members of a Brazilian crab harvesting community concerning environmental changes and the Lethargic Crab Disease.MethodsField work was undertaken during the period between January and April/2009, with weekly or biweekly field excursions during which open and semi-structured interviews were held with local residents in the municipality of Mucuri, Bahia State, Brazil. A total of 23 individuals were interviewed, all of whom had at least 20 years of crab-collecting experience in the study region. Key-informants (more experienced crab harvesters) were selected among the interviewees using the "native specialist" criterion.ResultsAccording to the collectors, LCD reached the Mucuri mangroves between 2004 and 2005, decimating almost all crab population in the area, and in 2007, 2008 and 2009 high mortalities of U. cordatus were again observed as a result of recurrences of this disease in the region. In addition to LCD, crabs were also suffering great stock reductions due to habitat degradation caused by deforestation, landfills, sewage effluents, domestic and industrial wastes and the introduction of exotic fish in the Mucuri River estuary. The harvesting community was found to have significant ecological knowledge about the functioning of mangrove swamp ecology, the biology of crabs, and the mass mortality that directly affected the economy of this community, and this information was largely in accordance with scientific knowledge.ConclusionsThe study of traditional knowledge makes it possible to better understand human interactions with the environment and aids in the elaboration of appropriate strategies for natural resource conservation.

An Appraisal of the Status and Distribution of Waterbirds of Algeria: Indicators of Global Changes?

Summary. An appraisal of the status and distribution of waterbirds of Algeria: indicators of global changes? North Africa is generally thought to play a key role for wintering and staging migrant birds. This study presents a detailed assessment of the status of waterbirds of Algeria with an emphasis on changes in species composition and distribution of breeding wetland and marine birds. A total of 97 species of waterbirds were identified with 41 species breeding. Marked environmental changes in North Africa over the past two hundred years that are relevant to waterbirds have included wetland drainage, persecution, introduction of exotic fish, increases in open-air refuse dumps and climate change. These changes have affected waterbirds differentially with some species increasing in numbers and expanding their range and others teetering on the verge of local extinction. When examining changes in the present breeding avifauna since the nineteenth century or the mid-twentieth century, the guild renewal rates ...

DNA barcoding of the ichthyofauna of Taal Lake, Philippines

This study represents the first molecular survey of the ichthyofauna of Taal Lake and the first DNA barcoding attempt in Philippine fishes. Taal Lake, the third largest lake in the Philippines, is considered a very important fisheries resource and is home to the world's only freshwater sardine, Sardinella tawilis. However, overexploitation and introduction of exotic fishes have caused a massive decline in the diversity of native species as well as in overall productivity of the lake. In this study, 118 individuals of 23 native, endemic and introduced fishes of Taal Lake were barcoded using the partial DNA sequence of the mitochondrial cytochrome c oxidase subunit I (COI) gene. These species belong to 21 genera, 17 families and 9 orders. Divergence of sequences within and between species was determined using Kimura 2-parameter (K2P) distance model, and a neighbour-joining tree was generated with 1000 bootstrap replications using the K2P model. All COI sequences for each of the 23 species were clearly discriminated among genera. The average within species, within genus, within family and within order percent genetic divergence was 0.60%, 11.07%, 17.67% and 24.08%, respectively. Our results provide evidence that COI DNA barcodes are effective for the rapid and accurate identification of fishes and for identifying certain species that need further taxonomic investigation.

Major changes in trophic dynamics in large, deep sub‐alpine Lake Maggiore from 1940s to 2002: a high resolution comparative palaeo‐neolimnological study

Summary1. We describe the changes in trophic dynamics in Lake Maggiore from c. 1943 to 2002 using subfossil cladoceran data from a high resolution sediment record, long‐term contemporary data series and historical information. During this period the lake went through a eutrophication phase until 1980 followed by oligotrophication.2. During the eutrophication period a major increase occurred in the abundance of Chydorus sphaericus, the proportion of planktonic cladocerans and total abundance of cladocerans in the sediment. Since 1980 the abundance declined again and subfossil Eubosmina mucro length and contemporary Daphnia body length increased, most probably as a result of higher abundance of invertebrate predators.3. Changes in the fish stock composition caused by the introduction of exotic fish during the pre‐eutrophication period and a complete ban on fishing because of Dichloro‐diphenil‐ethanes (DDTs) pollution of the lake (during oligotrophication) could also be detected in the community assemblage and size structure of the sediment zooplankton.4. We found good correspondence between trophic changes inferred from cladoceran subfossils (community composition, size and predation pressure) and contemporary data, suggesting that sediment samples can be used to infer past development in trophic dynamics, including predation by fish and pelagic invertebrates in lakes with scarce neolimnological data.5. Furthermore, by combining palaeolimnological cladoceran data rarely obtained from contemporary samples (e.g. benthic and plant‐associated cladocerans, mucro length of bosminids) with contemporary data of organisms poorly represented in the sediment record (e.g. remains of Bythotrephes and fishes) a more complete understanding of changes in trophic dynamics was obtained.6. The detection in the sediments of meteorological events whose effects on zooplankton had been recorded in the long‐term studies also provided evidence that eutrophication tends to override climate signals.7. We conclude that a combined palaeo‐neolimnological approach can be a powerful tool for elucidating past changes in the trophic dynamics of lakes and the interaction with climate induced changes, not least when high resolution sediment records are available.

A molecular identification key for freshwater mussel glochidia encysted on naturally parasitized fish hosts in Maine, USA

A molecular identification key for freshwater mussel glochidia encysted on naturally parasitized fish hosts in Maine, USA

Freshwater fishes of Patagonia in the 21st Century after a hundred years of human settlement, species introductions, and environmental change

We review the status of the freshwater fish fauna of Patagonia, an assemblage with 26 native species, comprising fishes of Gondwanan origin, marine dispersants, and oceanic elements of local origin. Several processes, old and new, have shaped the landscape of Patagonia and its fauna: a Gondwanan heritage, the Andes uplifting, Pleistocene ice, volcanic activity, introduction of exotic fishes, mostly Salmonids, and climate change. While there is a significant tradition of taxonomic work on native fish species, research on life history, trophic relationships, and community structure has started to emerge only in the last 15 years. Most studies were conducted in oligotrophic lakes of the Andes; while fauna of streams remains poorly observed. While documentation of impacts by salmonids is scarce, there is some compelling evidence indicating that freshwater communities have been significantly shaped by exotic fish. Impacts by exotic species appear to be dependent on temperature on the east side of the Andes, and land use and watershed perturbation on the west side.In general, freshwater habitat conditions and how they affect fishes are poorly studied. In lakes, habitat complexity and its specialized use by native fishes may have ameliorated the impact by introduced salmonids. Although impacts on rivers abound, led by dam construction, the relationship between stream habitat integrity and native species health is still poorly understood. The future of freshwater resources will largely depend on how able we are to inform managers, the general public and colleagues about their value and the costs of not taking action. But current research capacity is insufficient to deal with most demands because of limitations in people, resources and baseline information. To support our claims, we need to promote regional assessments of freshwater resources and of major threats to their integrity, the building blocks of a regional agenda for their sustainable use.