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We present a genome assembly from an individual female Phoxinus phoxinus (the Eurasian minnow; Chordata; Actinopteri; Cypriniformes; Leuciscidae). The genome sequence spans 950.50 megabases. Most of the assembly is scaffolded into 25 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 18.36 kilobases in length.

AbstractPhoxinus sedelnikowi is a Central Asian representative of the genus Phoxinus, occurring in the tributaries of Lake Zaisan at the southern foot of the Altai Mountains. Its systematic position has so far been unclear. It was considered a subspecies of Rhynchocypris czekanowskii, R. lagowskii and P. phoxinus. Here, we sequenced the cytochrome b gene and ATP-ase subunits 6 and 8 of representatives of P. sedelnikowi and two populations of P. phoxinus (including the topotypical population) and R. czekanowskii, R. lagowskii, and R. percnurus. We also performed an analysis of the shapes of the seven bones of the skull of all six forms examined and then performed a phylogenetic interpretation of the obtained results. Both P. sedelnikowi and Phoxinus sp. from the Solonovka population appeared to be separate from P. phoxinus from the topotypical population by Cytb: 0.11 and ATP: 0.13 distance. Therefore, they may be considered as independent species within the genus Phoxinus. We found the generic level genetic distance between Phoxinus and Rhynchocypris (Cytb: 0.24 and ATP: 0.68), which thus confirmed their independence. Genetic analyses revealed that one of the studied individuals of R. lagowskii shares the ATP haplotype with R. czekanowskii. The Cytb haplotype of this individual is also closest to that of R. czekanowskii, indicating an introgression between these forms and questioning their species status. The UPGMA and MP analysis of the selected osteological features confirmed the differentiation between Phoxinus and Rhynchocypris on the generic level. The results at lower taxonomic levels are not consistent with the identified genetic diversity, suggesting that osteological features may not be sufficient to distinguish forms at the intra-generic level.

Phoxinus sedelnikowi is a Central Asian representative of the genus Phoxinus, occurring in the tributaries of Lake Zaisan at the southern foot of the Altai Mountains. Its systematic position has so far been unclear. It was considered a subspecies of Rhynchocypris czekanowskii, R. lagowskii and P. phoxinus. Here, we sequenced the cytochrome b gene and ATP-ase subunits 6 and 8 of representatives of P. sedelnikowi and two populations of P. phoxinus (including the topotypical population) and R. czekanowskii, R. lagowskii, and R. percnurus. We also performed an analysis of the shapes of the seven bones of the skull of all six forms examined and then performed a phylogenetic interpretation of the obtained results. Both P. sedelnikowi and Phoxinus sp. from the Solonovka population appeared to be separate from P. phoxinus from the topotypical population by Cytb: 0.11 and ATP: 0.13 distance. Therefore, they may be considered as independent species within the genus Phoxinus. We found the generic level genetic distance between Phoxinus and Rhynchocypris (Cytb: 0.24 and ATP: 0.68), which thus confirmed their independence. Genetic analyses revealed that one of the studied individuals of R. lagowskii shares the ATP haplotype with R. czekanowskii. The Cytb haplotype of this individual is also closest to that of R. czekanowskii, indicating an introgression between these forms and questioning their species status. The UPGMA and MP analysis of the selected osteological features confirmed the differentiation between Phoxinus and Rhynchocypris on the generic level. The results at lower taxonomic levels are not consistent with the identified genetic diversity, suggesting that osteological features may not be sufficient to distinguish forms at the intra-generic level. [ABSTRACT FROM AUTHOR]

Abstract Assessing the status and distribution of fish populations in rivers is essential for management and conservation efforts in these dynamic habitats. Currently, methods detecting environmental DNA (eDNA) are being established as an alternative and/or complementary approach to the traditional monitoring of fish species. In lotic systems, a sound understanding of hydrological conditions and their influence on the local target detection probability and DNA quantity is key for the interpretation of eDNA‐based results. However, the effect of seasonal and diurnal changes in discharge and the comparability of semi‐quantitative results between species remain hardly addressed. We conducted a cage experiment with four fish species (three salmonid and one cyprinid species) in a glacier‐fed, fish‐free river in Tyrol (Austria) during summer, fall, and winter discharge situations (i.e., 25‐fold increase from winter to summer). Each season, water samples were obtained on three consecutive days at 13 locations downstream of the cages including lateral sampling every 1–2 m across the wetted width. Fish eDNA was quantified by species‐specific endpoint PCR followed by capillary electrophoresis. Close to the cages, lateral eDNA distribution was heterogenous and mirrored cage placement within the stream. In addition to the diluting effect of increased discharge, longitudinal signal changes within the first 20 m were weakest at high discharge. For downstream locations with laterally homogenous eDNA distribution, the signals decreased significantly with increasing distance and discharge. Generally, the eDNA of the larger‐bodied salmonid species was less frequently detected, and signal strengths were lower compared to the cyprinid species. This study exemplifies the importance of hydrological conditions for the interpretation of eDNA‐based data across seasons. To control for heterogenous eDNA distribution and enable comparisons over time, sampling schemes in lotic habitats need to incorporate hydrological conditions and species traits.

Since 2006, Great Cormorants Phalocrocorax carbo sinensis have wintered in the area of the river Geul, a right-bank tributary of the river Meuse, in the province of Limburg in the south of The Netherlands. Although the number of birds there is relatively small (approximately 30 birds), the local sports fishery sector is concerned about the possible impact on wild Brown Trout Salmo trutta, particularly on the young year-classes, through predation by wintering Cormorants. The number of birds, as well as their estimated fish consumption, was studied in the winter of 2012. Analysis of 70 diet samples (pellets) taken from the roost local to the area, showed that predation was primarily on young year classes of cyprinids, like Roach Rutilus rutilus. These cyprinids, and probably also the few trout consumed, were thought to have been mainly taken from farmed fish ponds in the direct neighbourhood of the river Geul. Besides predation of larger cyprinids, the Cormorants also took abundant small riverine fish species (2–10 cm) like Rhine Sculpin Cottus rhenanus and smaller cyprinid species like Minnow Phoxinus phoxinus and Gudgeon Gobio gobio. These riverine fishes have increased recently due to ameliorated water quality. The estimated fish consumption by Cormorants in the present study suggests limited or no impact on Brown Trout during winter. [ABSTRACT FROM AUTHOR]

We characterised morphologically and molecularly Diplostomum phoxini (Faust, 1918) based on cercarial isolates from the snail Ampullaceana balthica (L.) (Gastropoda: Lymnaeidae) and metacercariae from the Eurasian minnow, Phoxinus phoxinus (L.) (Cypriniformes: Leuciscidae), and provided molecular evidence for the identification of the snail intermediate host. Phylogenetic analyses based on the cytochrome c oxidase subunit 1 (cox1) gene depicted 44 molecularly characterised species and genetically distinct lineages of Diplostomum, and resulted in: (i) a re-identification/re-classification of 98 isolates plus D. baeri sampled in North America; (ii) re-definition of the composition of the D. baeri species complex which now includes nine molecularly characterised species/lineages; (iii) re-definition of the composition of the D. mergi species complex which now includes seven molecularly characterised species/lineages; and (iv) an updated nomenclature for the molecularly characterised species-level lineages of Diplostomum. [ABSTRACT FROM AUTHOR]

Anthropogenic noise can affect animals physically, physiologically, and behaviourally. Although individual responses to noise are well documented, the consequences in terms of community structure, species coexistence, and ecosystem functioning remain fairly unknown.The impact of noise on predation has received a growing interest and alterations in trophic links are observed when animals shift from foraging to stress‐related behaviours, are distracted by noise, or because of acoustic masking. However, the experimental procedures classically used to quantify predation do not inform on the potential demographic impact on prey.We derived the relationship between resource use and availability (the functional response) for European minnows (Phoxinus phoxinus) feeding on dipteran larvae (Chaoborus sp.) under two noise conditions: ambient noise and ambient noise supplemented with motorboat noise. The shape and magnitude of the functional response are powerful indicators of population outcomes and predator–prey dynamics. We also recorded fish behaviour to explore some proximate determinants of altered predation.For both noise conditions, fish displayed a saturating (type II) functional response whose shape depends on two parameters: attack rate and handling time. Boat noise did not affect handling time but significantly reduced attack rate, resulting in a functional response curve of the same height but with a less steep initial slope. Fish exhibited a stress‐related response to noise including increased swimming distance, more social interactions, and altered spatial distribution.Our study shows the usefulness of the functional response approach to study the ecological impacts of noise and illustrates how the behavioural responses of predators to noise can modify the demographic pressure on prey. It also suggests that prey availability might mediate the negative effect of noise on predation. Community outcomes are expected if the reduced consumption of the main food sources goes with the overconsumption of alternative food sources, changing the distribution pattern of interaction strengths. Predation release could also trigger a trophic cascade, propagating the effect of noise to lower trophic levels. [ABSTRACT FROM AUTHOR]

Functional traits can covary to form "functional syndromes." Describing and understanding functional syndromes is an important prerequisite for predicting the effects of organisms on ecosystem functioning. At the intraspecific level, functional syndromes have recently been described, but very little is known about their variability among populations and—if they vary—what the ecological and evolutionary drivers of this variation are. Here, we quantified and compared the variability in four functional traits (body mass, metabolic rate, excretion rate, and boldness), their covariations and the subsequent syndromes among thirteen populations of a common freshwater fish (the European minnow, Phoxinus phoxinus). We then tested whether functional traits and their covariations, as well as the subsequent syndromes, were underpinned by the phylogenetic relatedness among populations (historical effects) or the local environment (i.e., temperature and predation pressure), and whether adaptive (selection or plasticity) or nonadaptive (genetic drift) processes sustained among‐population variability. We found substantial among‐population variability in functional traits and trait covariations, and in the emerging syndromes. We further found that adaptive mechanisms (plasticity and/or selection) related to water temperature and predation pressure modulated the covariation between body mass and metabolic rate. Other trait covariations were more likely driven by genetic drift, suggesting that nonadaptive processes can also lead to substantial differences in trait covariations among populations. Overall, we concluded that functional syndromes are population‐specific, and that both adaptive and nonadaptive processes are shaping functional traits. Given the pivotal role of functional traits, differences in functional syndromes within species provide interesting perspectives regarding the role of intraspecific diversity for ecosystem functioning. Previous works have shown that functional traits can be involved in multiple covariations, generating functional syndromes. This study quantifies and assesses the determinants of the variability in functional syndromes among thirteen populations of the European minnow (Phoxinus phoxinus). We found that syndromes were heterogeneous among populations, and that both adaptive processes related to water temperature and predation pressure and nonadaptive processes (genetic drift) modulated these syndromes. [ABSTRACT FROM AUTHOR]

Phoxinus phoxinus is a small Leuciscinae species predominantly found in cool and well-oxygenated streams throughout a wide area encompassing Europe, Siberia and East Asia. It is believed that the populations in Korea hold important clues to how the species has been distributed south along the Eurasian continent to the Korean Peninsula. We characterized the complete mitochondrial genomes of two individual fin-clip samples collected from the two Korean river systems. The whole sequences were 17,665 and 18,220 bp, respectively, and included 13 protein-coding genes, 2 ribosomal RNA genes and 22 transfer RNA genes. The genome size difference was due to the considerably different sizes of the control region. The overall genome structures were identical to those observed in other Leuciscinae species.

Management decisions in conservation of threatened species require trading off social needs against biodiversity values, including the prioritization of conservation locations, i.e. where conservation efforts should take place. To improve conservation decisions for the thick-shelled river mussel, Unio crassus, a highly threatened temporary parasite on fish, we performed a field study on how mussel and host fish density (European bullhead, Cottus gobio, and common minnow, Phoxinus phoxinus) affect reproduction potential of the mussel at different sites along a river. We assumed that the proportions of gravid mussels would be higher at high mussel density, and result in enhanced glochidia (mussel larvae) encapsulation rates on fish. We also expected the highest 'glochidia density'—a proxy for the potential number of recruits per stream area, assessed by multiplying glochidia encapsulation rates on fish by fish density, to occur at high mussel density sites. Such river sites, producing many offspring and conveying important conservation values, may thus be prioritized. However, contrary to our assumptions, higher glochidia density and higher proportions of gravid mussels occurred at lower density mussel sites. We also found that P. phoxinus had higher glochidia encapsulation rates than C. gobio, possibly related to species-specific behavioural and life-history traits. Even so, glochidia density was similar for both fish species, reflecting comparable ecological functions in hosts. The results of this study suggest that mussel and host fish densities should be considered along with glochidia density in conservation prioritization and management trade-offs. [ABSTRACT FROM AUTHOR]

1. Recent findings highlighted the central role of the structure of the river network in shaping spatial patterns of genetic diversity in riverscapes. However, the influence of multiple anthropogenic stressors on these patterns may be just as important and the relative impacts of these two types of predictors have rarely been quantified simultaneously in river networks. Here, we contributed to filling this gap by investigating the relative contribution of both network structure and multiple anthropogenic stressors in shaping spatial patterns of genetic diversity in two freshwater fishes (Gobio occitaniae and Phoxinus phoxinus). 2. We focused on two rivers in which the two fish species were sampled along the upstream-downstream gradient. Microsatellite markers were used to quantify genetic diversity from three indices: allelic richness, private allelic richness and genetic uniqueness. Each sampling site was physically characterised according to its position in the network, and was described for multiple anthropogenic stressors including habitat degradation, fragmentation and stocking. This multiple-stressors approach was conducted using a fully explicit and generalisable analytical framework designed to cope with strong collinearity among environmental variables. 3. Overall, the contribution of network structure to the variance in genetic diversity was 1.8 times higher than the contribution of anthropogenic stressors. Both the position of sites along the upstream-downstream gradient and stocking were strong and consistent drivers of genetic variability. Conversely, the local influences of habitat degradation and fragmentation were species- and river-specific, sometimes even varying along the river channel, thus preventing any generalisations. 4. We concluded that the natural structure of networks and stocking strongly influence spatial patterns of genetic diversity in a predictable way, whereas the influence of other human activities may be much more difficult to predict over species and contexts. [ABSTRACT FROM AUTHOR]

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

This study focuses on plerocercoids of the cestode Diphyllobothrium ditremum in brown trout Salmo trutta from the subalpine lake Øvre Heimdalsvatn in south-central Norway. Salmo trutta was the only fish species in this lake until European minnow Phoxinus phoxinus was registered in 1969. The P. phoxinus population increased substantially in the following years. In contrast with the 1969-1972 period, when plerocercoids of D. ditremum were practically absent in S. trutta, there was a high prevalence and intensity of infection in the 2013 S. trutta samples. Because the life cycle of D. ditremum involves two larval stages, in copepods and salmonids and mature worms in piscivorous birds, such as mergansers and loons, a change in feeding ecology of S. trutta or changes in population densities of copepods, fish or birds might have influenced the infection pattern. No relationships between D. ditremum infection and muscle-tissue δ15N signature or Hg concentration were found, indicating that infection is not a result of piscivory or cannibalism. Furthermore, consumption of copepods by S. trutta during summer and autumn was low. On the other hand, the number of piscivorous birds has increased, probably due to the presence of P. phoxinus as a new and numerous prey. An increased number of final D. ditremum hosts may have produced a higher output of cestode eggs, resulting in more infected copepods that in turn are consumed by S. trutta. Indirectly, P. phoxinus may therefore have caused the observed increased infection in S. trutta and thereby imposed further negative effects on S. trutta in high mountain areas. [ABSTRACT FROM AUTHOR]

Background: Molecular taxonomy studies and barcoding projects can provide rapid means of detecting cryptic diversity. Nevertheless, the use of molecular data for species delimitation should be undertaken with caution. Especially the single-gene approaches are linked with certain pitfalls for taxonomical inference. In the present study, recent and historical species descriptions based upon morphology were used as primary species hypotheses, which were then evaluated with molecular data (including in type and historical museum material) to form secondary species hypotheses. As an example of cryptic diversity and taxonomic controversy, the European Phoxinus phoxinus species complex was used. Results: The results of the revision showed that of the fourteen primary species hypotheses, three were rejected, namely P. ketmaieri, P. likai, and P. apollonicus. For three species (P. strandjae, P. strymonicus, P. morella), further investigation with increased data sampling was suggested, while two primary hypotheses, P. bigerri and P. colchicus, were supported as secondary species hypotheses. Finally, six of the primary species hypotheses (P. phoxinus, P. lumaireul, P. karsticus, P. septimanae, P. marsilii and P. csikii) were well supported by mitochondrial but only limitedly corroborated by nuclear data analysis. Conclusion: The approach has proven useful for revision of species complexes, and the study can serve as an overview of the Phoxinus genus in Europe, as well as a solid basis for further work. [ABSTRACT FROM AUTHOR]

Expert judgment is regularly used in ecology for assessing the suitability of habitats, in particular of rare or endangered species or species with limited empirical data. Yet, differences in expert judgment of habitat suitability and consequent implications for ecosystem management have not been evaluated and are largely ignored. Here, we evaluated the variability of 13 expert judgments and the related uncertainty in hydraulic habitat suitability modelling using the riverine fish species Phoxinus phoxinus as a model species. We found (i) the highest agreement among experts identifying the best and fully unsuited habitat conditions, but (ii) that disagreement among experts is surprisingly large, (iii) with largest differences related to the experts' perception of flow velocity and (iv) that semi-suitable transition areas between high and low habitat suitability are most susceptible to disagreements. We emphasize that expert judgment of habitat suitability is useful for many applications and especially highly suitable habitats would be reliably identified by experts. However, expert judgment-based assessments should be iterative processes that include both different experts and feedback on the potential effects of their assessments. Furthermore, we recommend that expert judgment should not replace data-driven empirical ecology but its benefits can rather complement it. [ABSTRACT FROM AUTHOR]

Minnows of the genus Phoxinus are promising candidates to investigate adaptive divergence, as they inhabit both still and running waters of a variety of altitudes and climatic zones in Europe. We used landmark-based geometric morphometric methods to quantify the level of morphological variability in Phoxinus populations from streams and lakes of Northern Italy and the Danube basin. We analyzed body shape differences of populations in the dorsal, lateral, and ventral planes, using a large array of landmarks and semilandmarks. As the species identification of Phoxinus on morphological characters is ambiguous, we used two mitochondrial genes to determine the genetic background of the samples and to ensure we are comparing homogenous groups. We have found significant body shape differences between habitats: Minnow populations inhabiting streams had a deeper body and caudal peduncle and more laterally inserted pectoral fins than minnows inhabiting lakes. We have also found significant body shape differences between genetic groups: Italian minnows had deeper bodies, deeper and shorter caudal peduncles, and a shorter and wider gape than both groups from the Danube. Our results show that the morphology of Phoxinus is highly influenced by habitat and that body shape variation between habitats was within the same range as between genetic groups. These morphological differences are possibly linked to different modes of swimming and foraging in the respective habitats and are likely results of phenotypic plasticity. However, differences in shape and interlandmark distances between the groups suggest that some (though few) morphometric characters might be useful for separating Phoxinus species. [ABSTRACT FROM AUTHOR]

Our understanding on the role of chemical signals in parasite-mediated sexual selection is still limited, and only some existing studies have focused on fish. Furthermore, published studies on the effect of parasite infection on behavioral sexual competition of the male hosts have yielded contradictory results. Here, we examined whether the infection of the body cavity-dwelling parasitic nematode Philometra ovata influences odor-based female choice and behavioral sexual competition (dominance and courtship behavior) between males in the European minnow ( Phoxinus phoxinus), the cyprinid fish host. In contrast to our predictions, we found that naïve females showed no preference between the odors of infected and non-infected males, thus indicating that P. ovata infection may not affect odor-based female choice. Moreover, P. ovata did not impair sexual competitiveness of their hosts either. Our results indicate that despite its relatively large size, P. ovata may not alter sexual cues and the success of the male hosts in sexual selection. [ABSTRACT FROM AUTHOR]

The thick-shelled river mussel Unio crassus is an endangered freshwater bivalve species with a life cycle that includes an obligate glochidial larval stage that attaches to the gills of freshwater fish for several days to months., Fish hosts were identified in nine north-eastern French rivers in order to improve unionid conservation management., Eurasian minnow Phoxinus phoxinus was the most important host at all study sites, with prevalence ranging from 15-100% (122 of 238 individuals infested), and bullhead Cottus gobio usually the second most important (prevalence 0-73%; 37 of 121). Other host species had a relatively low rate of infestation: chub Squalius cephalus (5 of 41), roach Rutilus rutilus (1 of 23), gudgeon Gobio gobio (2 of 50), stone loach Barbatula barbatula (2 of 58) and dace Leuciscus leuciscus (1 of 19). No glochidia were found on spirlin Alburnoides bipunctatus (0 of 24)., Parasitic load usually ranged between one and three per fish (60% of cases), and rarely exceeded 10. First results suggest that U. crassus glochidia influence the weight:length ratio of P. phoxinus but not C. gobio, with infested fish being heavier., To date, the ecological function of P. phoxinus (and C. gobio) in small streams has been largely underestimated or ignored as the species is small, common and of no interest to anglers. There is increasing evidence, however, that P. phoxinus deserves conservation management owing to the essential role it plays in the reproduction, development and distribution of U. crassus., Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The influence of trophically transmitted parasite infection on fitness-related locomotor performance in fish as definite hosts has been studied relatively rarely and is thus mostly unknown. In this study, we examined the effect of body cavity dwelling nematodePhilometra ovataon the swimming performance, fitness-related traits (male body quality) and male sexual ornamentation of their definitive host, European minnow (Phoxinus phoxinus). Despite the fact thatP. ovatais relatively large in body size and thus presumably costly for their host minnows, we found that the abundance of the parasite did not correlate with the swimming performance of the male minnows. Neither did the infection ofP. ovataimpair the male sexual ornamentation or the male body quality. These partly unexpected results highlight the fact that theP. ovatainduced impairment on fitness-related traits of host male minnows is not straightforward, and thus additional physiological studies in infected minnows are needed before final conclusions about the actual harmfulness of the parasite can be made. [ABSTRACT FROM AUTHOR]

Neutral and selective processes can drive repeated patterns of evolution in different groups of populations experiencing similar ecological gradients. In this paper, we used a combination of nuclear and mitochondrial DNA markers, as well as geometric morphometrics, to investigate repeated patterns of morphological and genetic divergence of European minnows in two mountain ranges: the Pyrenees and the Alps. European minnows ( Phoxinus phoxinus) are cyprinid fish inhabiting most freshwater bodies in Europe, including those in different mountain ranges that could act as major geographical barriers to gene flow. We explored patterns of P. phoxinus phenotypic and genetic diversification along a gradient of altitude common to the two mountain ranges, and tested for isolation by distance ( IBD), isolation by environment ( IBE) and isolation by adaptation ( IBA). The results indicated that populations from the Pyrenees and the Alps belong to two well differentiated, reciprocally monophyletic mt DNA lineages. Substantial genetic differentiation due to geographical isolation within and between populations from the Pyrenees and the Alps was also found using rapidly evolving AFLPs markers (isolation by distance or IBD), as well as morphological differences between mountain ranges. Also, morphology varied strongly with elevation and so did genetic differentiation to a lower extent. Despite moderate evidence for IBE and IBA, and therefore of repeated evolution, substantial population heterogeneity was found at the genetic level, suggesting that selection and population specific genetic drift act in concert to affect genetic divergence. [ABSTRACT FROM AUTHOR]

Seasonal life cycle of body cavity dwelling (BCD) Philometra ovata (Nematoda: Philometridae) has been reported in southern and central European countries, but its swim bladder dwelling (SBD) stage and northern populations have remained unstudied. In this study, we investigated the seasonal life cycle and infection ecology of P. ovata in both swim bladder and body cavity in the European minnow (Phoxinus phoxinus) in Finland. The larval P. ovata infected the swim bladder of minnows mainly in August. Female SBD P. ovata emigrated to body cavity mostly in September, grew to their full size by the end of the next June, and evacuated from minnows in July. In addition, female SBD P. ovata retarding their development and staying in swim bladder were found commonly in minnows, thus the mean monthly prevalence (6·7 ± 3·9%) and mean intensity (1·4 ± 0·8) of BCD P. ovata was lower than that of SBD P. ovata (37·8 ± 15·1% and 2·0 ± 1·5, respectively). Finally, despite the large size of BCD individuals, infection of P. ovata did not impair body condition and relative gonad size of minnows, but increased the mortality and caused physical damages in their hosts during the evacuation period. [ABSTRACT FROM AUTHOR]

This study represents the first comprehensive molecular assessment of freshwater fishes and lampreys from Germany. We analysed COI sequences for almost 80% of the species mentioned in the current German Red List. In total, 1056 DNA barcodes belonging to 92 species from all major drainages were used to (i) build a reliable DNA barcode reference library, (ii) test for phylogeographic patterns, (iii) check for the presence of barcode gaps between species and (iv) evaluate the performance of the barcode index number ( BIN) system, available on the Barcode of Life Data Systems. For over 78% of all analysed species, DNA barcodes are a reliable means for identification, indicated by the presence of barcode gaps. An overlap between intra- and interspecific genetic distances was present in 19 species, six of which belong to the genus Coregonus. The Neighbour-Joining phenogram showed 60 nonoverlapping species clusters and three singleton species, which were related to 63 separate BIN numbers. Furthermore, Barbatula barbatula, Leucaspius delineatus, Phoxinus phoxinus and Squalius cephalus exhibited remarkable levels of cryptic diversity. In contrast, 11 clusters showed haplotype sharing, or low levels of divergence between species, hindering reliable identification. The analysis of our barcode library together with public data resulted in 89 BINs, of which 56% showed taxonomic conflicts. Most of these conflicts were caused by the use of synonymies, inadequate taxonomy or misidentifications. Moreover, our study increased the number of potential alien species in Germany from 14 to 21 and is therefore a valuable groundwork for further faunistic investigations. [ABSTRACT FROM AUTHOR]

Recruitment and dispersal of freshwater mussels of the Unionoida is strongly linked to their host fishes on which the larvae develop into juvenile mussels. Host limitation has been suggested as one of the potential causes for the decline of the formerly widespread thick-shelled river mussel ( Unio crassus), although quantitative data analysing the importance of this factor are still missing., In this study, the status of host fish populations was assessed in nine U. crassus streams within the Danube drainage system situated in southern Germany. In particular, links between recruitment patterns of U. crassus populations, fish species composition and quantitative data of host fish densities in functional and non-functional streams were established., Fish species composition and richness ranged between three and nine species with no difference in presence data between functional and non-functional streams. Despite this high variability, functional U. crassus streams with high proportions of juvenile mussels had significantly higher (mean: 40 Ind. per 100 m2) densities of primary hosts ( Phoxinus phoxinus, Squalius cephalus, Gasterosteus aculeatus) than non-functional streams (mean: 8 Ind. per 100 m2). In contrast, no relationship was found between the numbers and densities of juvenile mussels and densities of poor hosts as well as of non-hosts., The results of this study indicate that the recruitment status of U. crassus strongly depends on the density of primary host fish species. Host limitation is likely to play a major role in a lack of juvenile recruitment and consequently in the decline of central European U. crassus populations. Therefore, future conservation for this endangered mussel species should more thoroughly incorporate management of host fish species and consider both the requirements of mussels and their hosts in habitat restoration., Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Although high mountain lakes are naturally fishless, there have been numerous trout introductions to such ecosystems in many areas of the world with negative ecological consequences. In recent decades other fishes, such as minnows, have been introduced to some mountain areas, including the Pyrenees. These introductions may cause further ecological problems, since minnows also occupy the top of the food chain, and are difficult to manage since such introductions occur without permission from the authorities. In this study we have analyzed the process of minnow introductions in all high mountain lakes of the southern slope of the Pyrenees to find out which particular factors best explained their present distribution and to evaluate which management measures have been most effective for stopping introductions. We found 27 % of the lakes had minnows ( Phoxinus sp.) present, 52 % had trout and 47 % were fishless. Trout presence was the most significant variable explaining 27 % of deviance of minnow presence data in a generalized additive model. Recreational fishing using minnows as live bait is likely responsible for these introductions. Minnow introductions are therefore mediated by a preceding invasive species and facilitated by human activity. We also compared the number of minnow introductions in non-fishing areas of National Parks with other areas where managed fishing takes place. We found that the number of lakes with minnow introductions was increasing in all areas except those where fishing was prohibited, indicating that prohibiting fishing is an effective management practice for stopping minnow introductions. [ABSTRACT FROM AUTHOR]

Phoxinus phoxinus is a small Leuciscinae species predominantly found in cool and well-oxygenated streams throughout a wide area encompassing Europe, Siberia and East Asia. It is believed that the populations in Korea hold important clues to how the species has been distributed south along the Eurasian continent to the Korean Peninsula. We characterized the complete mitochondrial genomes of two individual fin-clip samples collected from the two Korean river systems. The whole sequences were 17,665 and 18,220 bp, respectively, and included 13 protein-coding genes, 2 ribosomal RNA genes and 22 transfer RNA genes. The genome size difference was due to the considerably different sizes of the control region. The overall genome structures were identical to those observed in other Leuciscinae species. [ABSTRACT FROM AUTHOR]

Metacercariae of trematodes from the genus Diplostomum are major helminth pathogens of freshwater fish, infecting the eye or the brain. The taxonomy of the genus Diplostomum is complicated, and has recently been based mainly on the molecular markers. In this study, we report the results of the morphological and molecular genetic analysis of diplostomid metacercaria from the brain of the minnow Phoxinus phoxinus from three populations in Fennoscandia (Northern Europe) and one population in Mongolia (East Asia). We obtained the data on the polymorphism of the partial mitochondrial cox1 gene and ribosomal ITS1–5.8S–ITS2 region of these parasites. РСА-based morphological analysis revealed that the parasites in the Asian and the European groups of Diplostomum sp. were distinctly different. Metacercariae from the brain of Mongolian minnows were much larger than those from the brain of Fennoscandian minnows but had much fewer excretory granules. Considering that the two study regions were separated by a distance of about 4500 km, we also tested the genetic homogeneity of their host, the minnow, using the mitochondrial cytb gene. It was shown that Diplostomum -infected minnows from Mongolia and Fennoscandia represented two previously unknown separate phylogenetic lineages of the genus Phoxinus. Both molecular and morphological analysis demonstrated that the parasites from Fennoscandia belonged the species Diplostomum phoxini , while the parasites from Mongolia belonged to a separate species, Diplostomum sp. MТ. Each of the two studied Diplostomum spp. was associated with a specific, and previously unknown, genealogical lineage of its second intermediate host, P. phoxinus. • Two distinct species of ' Phoxinus phoxinus ' complex inhabit in Fennoscandia and Mongolia. • Two distinct species of ' Diplostomum phoxini ' complex parasitize brain of minnows in Fennoscandia and Mongolia. • Each of brain species is associated with specific genealogical lineages (European and Asian) of minnow as the second intermediate fish host. [ABSTRACT FROM AUTHOR]

As reported, previous studies ofPhoxinus phoxinus ujmonensis(Cypriniformes: Cyprinidae) have focused primarily on morphology and ecology. In this study, we cloned and sequenced the complete nucleotide sequence of the mitochondrial genome forP. phoxinus ujmonensis. The mitogenome was 17,738 bp in length, including 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and 1 control region. All genes were encoded on the heavy strain except for ND6 and eight tRNA genes. The overall base composition of the heavy strain was 28.50% for A, 28.24% for T, 25.32% for C and 17.94% for G. The control region was revealed to contain tandem repeats. The mitogenome data ofP. phoxinus ujmonensisshould contribute to phylogenetic analysis and studies of population genetics ofPhoxinusfishes. [ABSTRACT FROM AUTHOR]

The harvest of animals by humans may constitute one of the strongest evolutionary forces affecting wild populations. Vulnerability to harvest varies among individuals within species according to behavioural phenotypes, but we lack fundamental information regarding the physiological mechanisms underlying harvest-induced selection. It is unknown, for example, what physiological traits make some individual fish more susceptible to capture by commercial fisheries. Active fishing methods such as trawling pursue fish during harvest attempts, causing fish to use both aerobic steady-state swimming and anaerobic burst-type swimming to evade capture. Using simulated trawling procedures with schools of wild minnows Phoxinus phoxinus, we investigate two key questions to the study of fisheries-induced evolution that have been impossible to address using large-scale trawls: (i) are some individuals within a fish shoal consistently more susceptible to capture by trawling than others?; and (ii) if so, is this related to individual differences in swimming performance and metabolism? Results provide the first evidence of repeatable variation in susceptibility to trawling that is strongly related to anaerobic capacity and swimming ability. Maximum aerobic swim speed was also negatively correlated with vulnerability to trawling. Standard metabolic rate was highest among fish that were least vulnerable to trawling, but this relationship probably arose through correlations with anaerobic capacity. These results indicate that vulnerability to trawling is linked to anaerobic swimming performance and metabolic demand, drawing parallels with factors influencing susceptibility to natural predators. Selection on these traits by fisheries could induce shifts in the fundamental physiological makeup and function of descendent populations. [ABSTRACT FROM AUTHOR]