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Cyprinid herpesvirus 2 (CyHV-2) is the agent of herpesviral haematopoietic necrosis (HVHN), a serious disease affecting two fish species of the Carassius genus, i.e. goldfish (C. auratus) and Prussian Carp (C. gibelio). In Poland, no asymptomatic vectors of CyHV-2 and no farms in which the virus would cause mortalities have been identified. In 2016 and 2017, mass mortalities of ornamental varieties of C. auratus were observed in a cage culture submerged in a channel receiving post-cooling water from the Dolna Odra power plant (north-western Poland). End-point PCRs and sequencing of the mA marker confirmed the presence of CyHV-2 DNA in the gills and pool (kidney, liver, gut and spleen) samples collected from four ornamental types of goldfish, i.e. Veiltail, Wakin, Red Cap Oranda and Ranchu imported from Thailand and UK. Further analysis revealed that the obtained sequences represent a new type of a 295-bp mA sequence (RSD-PL, GenBank accession no. KX852452.1), which had the greatest similarity to the AMS-8 and FR types of CyHV-2 identified in diseased fish imported from Israel and Asia, respectively. Additionally, our study identified common carp (Cyprinus carpio) individuals reared in neighbouring cages as asymptomatic carriers of CyHV-2. The virus was not detected in fish, i.e. ide (Leuciscus idus), perch (Perca fluviatilis), pumpkinseed (Lepomis gibbosus) and common bleak (Alburnus alburnus), collected from the environment of the power plant discharge channel. Identification of CyHV-2 is the first case reported in Poland and the only one in which blood, gills and pool samples of common carp were CyHV-2-positive. Our study identified the cause of mortalities of ornamental goldfish in cage culture, but also shed a new light on issues concerning the species-specificity of CyHV-2.

The utilization of fish bioindicators has become of crucial importance for ecosystem contamination assessment. Bleak (Alburnus alburnus) is a widely distributed epipelagic fish species characterized as very active with fast metabolism which can lead to a high accumulation of pollutants in tissues. Bleak is easy to sample, identify in the field by morphological characteristics, and easy to work within the laboratory. This study deals with the bleak sensitivity in detecting the pressure of the potentially toxic elements (PTEs) in the large lowland Great Morava River. The Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sn, and Zn were estimated in whole body composite (wbc) of bleak. The study was conducted at Great Morava River, near the city of Paraćin in Serbia. The highest concentrations of essential elements Zn and Fe were detected. The most toxic elements As and Hg were below detection limits. The metal pollution index (MPI) was 0.39. In large lowland rivers, point sources of pollution such as municipal wastewaters of smaller settlements usually have only local impact due to high dilution by the main watercourse. Since bleak is a site-specific species, results in this study indicated that this stretch of the Great Morava River is slightly affected by PTEs. None of the elements above the maximum permitted concentrations (MPC) in fish meat for use in the human diet, prescribed by the Official Gazette and European Commission Regulation, were not recorded.

Wildlife monitoring using passive telemetry has become a robust method for investigating animal migration. With increased use, this method progressively pollutes the environment with technological waste represented by so called ghost tags (PIT tags ending in the environment due to reproductive expulsions, shedding or animal mortality). However, their presence in the environment may lead to failed detections of living individuals. We used tagging data from studies of the asp Leuciscus aspius and the bleak Alburnus alburnus collected from 2014 to 2018 and located ghost tag positions on the monitored spawning site using portable backpack reader for their detection. We modelled virtual river-wide flat-bed antennas (widths 0.2, 0.4, 0.6 and 0.8 m) representing monitoring effort and estimated the probability of the presence of ghost tags within the antenna field. Of 3724 PIT tags used in the study, we detected on the spawning ground 173 ghost tags originating from long-term monitoring. The ghost tags accumulated in the environment in time, suggesting insufficient degradation rate or shift downstream from the research site. Number of ghost tags present on the spawning ground led to high probability of disabled readings of tagged fish passing through the antenna electro-magnetic field. We demonstrate how accumulated ghost tags may cause detection failures for focal species and incomplete data acquisition. We infer that intensive long-term monitoring using PIT tag technology may encumber future data acquisition or entail additional costs for clean-up.

This article belongs to the Special Issue Ecology and Conservation of Freshwater Fishes Biodiversity., The bleak Alburnus alburnus is native to most of Europe. This cyprinid fish is a successful invader in the Iberian Peninsula. No studies exist on its foraging strategies on a large scale for this ecoregion. The aim of the present study was to compare dietary traits of invasive bleak among the main Iberian rivers and a ‘reference’ native bleak population from France. Bleak were sampled during May–June 2019 from the Iberian Rivers Ebro, Tagus, Guadiana, Segura and Guadalquivir and the River Saône (France). Diptera larvae and zooplankton were common food categories in the River Saône. Insect nymphs were more important in the River Ebro. The intake of plant material was higher in the River Tagus. Flying insects were more consumed in the River Guadiana. Nektonic insects were important in the River Guadalquivir. Detritus was a frequent food category for all populations, in terms of occurrence and mass. Dietary parameters followed a unimodal response in relation to the latitudinal gradient, with the maximum values for the Tagus and Guadiana populations. Overall, results suggest that this wide interpopulation variability will contribute to the species’ successful establishment throughout Mediterranean Europe, which poses a serious risk to its highly valuable native fish fauna, This research was partly supported by the Spanish Ministry of Education (FPU 13/03291), the Spanish Ministry of Economy and Competitiveness (projects CGL2015-69311-REDT and CGL2016-80820-R) and the Government of Catalonia (ref. 2014 SGR 484).

Este artículo contiene 12 páginas, 3 tablas, 4 figuras., Energy metabolism fuels swimming and other biological processes. We compared the swimming performance and energy metabolism within and across eight freshwater fish species. Using swim tunnel respirometers, we measured the standard metabolic rate (SMR) and maximum metabolic rate (MMR) and calculated the critical swimming speed (Ucrit). We accounted for body size, metabolic traits, and some morphometric ratios in an effort to understand the extent and underlying causes of variation. Body mass was largely the best predictor of swimming capacity and metabolic traits within species. Moreover, we found that predictive models using total length or SMR, in addition to body mass, significantly increased the explained variation of Ucrit and MMR in certain fish species. These predictive models also underlined that, once body mass has been accounted for, Ucrit can be independently affected by total length or MMR. This study exemplifies the utility of multiple regression models to assess within-species variability. At interspecific level, our results showed that variation in Ucrit can partly be explained by the variation in the interrelated traits of MMR, fineness, and muscle ratios. Among the species studied, bleak Alburnus alburnus performed best in terms of swimming performance and efficiency. By contrast, pumpkinseed Lepomis gibbosus showed very poor swimming performance, but attained lower mass-specific cost of transport (MCOT) than some rheophilic species, possibly reflecting a cost reduction strategy to compensate for hydrodynamic disadvantages. In conclusion, this study provides insight into the key factors influencing the swimming performance of fish at both intra- and interspecific levels., This research was supported by the Spanish Ministry of Science, Innovation and Universities (projects CGL2013-43822-R and CGL2016-80820-R, AEI/ FEDER/EU) and the Government of Catalonia (ref. 2017 SGR 548). F.R.-G. was benefitted from a predoctoral fellowship from the University of Girona (IFUdG17).

Animals that do not provide parental care have to secure the survival of their offspring by ensuring a safe reproductive environment or smart timing tactics. Nocturnal spawning behaviour of many fish species is an example of the latter behaviour in the animal kingdom and is hypothesized to provide a survival advantage to the eggs spawned during the night. In order to test the efficiency of the smart timing tactics in a freshwater fish, a study was carried out of the interaction of the rheophilic spawner (asp Leuciscus aspius) and the predator of its drifting eggs (bleak Alburnus alburnus) using passive telemetry. According to a model based on acquired data, asp laid 63% of its eggs at night, while vision-oriented bleak was present in 92% of the time during the day. This study gives support to the predator avoidance hypothesis, which expects animals to reproduce in a period when the probability of offspring predation is at its lowest.

The sexual dimorphism of physiological and biochemical parameters of trunk muscle in bleak spawners, representatives of an abundant nonexploited fish species of the Rybinsk Reservoir, has been analyzed in the prespawning period. Sex-related differences in the overall biochemical and lipid composition of trunk muscle and in muscle composition variability in age- and size-matched individuals have been assessed. The distribution of trunk-muscle lipid content is bimodal in females and unimodal in males. The variability of muscle lipid parameters in the aggregated samples is higher in females than in males. The putative reasons for the distinctive features of physiological and biochemical parameters of muscle tissue detected in bleak of different sexes in the prespawning period are discussed.

The diurnal dynamics of the activity of peptidases in fish larvae by the example of bleak Alburnus alburnus (L.) as the dominant species in the open and protected shallows of the Rybinsk Reservoir has been studied for the first time. Two peaks of enzyme activity in the intestinal mucosa of fish larvae are revealed: morning and night. The data on species composition and daily dynamics of number of fish larvae in the shallows of different types are presented.

Fish communities differ significantly between the littoral and the pelagic habitats. This paper attempts to define the shift in communities between the two habitats based on the European standard gillnet catch. We sampled the benthic and pelagic habitats from shore to shore in Lake Most and Římov Reservoir (Czech Republic). The 3 m deep pelagic nets were spanned across the water body at equal distances from two boundary points, where the depth was 3.5 m. The benthic community contained more fish, more species, and smaller individuals. The mild sloped littoral with a soft bottom attracted more fish than the sloping bank with a hard bottom and less benthos and large Daphnia. The catch of the pelagic nets was dominated by eurytopic fish—rudd (Scardinius erythrophthalmus) and roach (Rutilus rutilus) in Most and bleak (Alburnus alburnus) in Římov. With the exception of one case where overgrown macrophytes extended the structured habitat, the largest shift from the benthic to the pelagic community was observed only in the first pelagic gillnet above the bottom depth of 3.5 m. Open water catches were relatively constant with small signs of decline towards the middle of the lake. The results indicate that the benthic gillnet catch is representative of a very limited area and volume, while most of the volume is dominated by the pelagic community. This has important consequences for the assessment of the community parameters of the whole lake following the European standards for gillnet sampling design.

This paper reports the results from mobile hydroacoustic surveys carried out between 1994 and 2018, to assess the fish stocks in four impounded reaches, covering 19.8 km of the River Thames, England. The data are complemented with electric fishing boom boat results, collected at the same study reaches and time periods. Hydroacoustic surveys used inter-calibrated dual and split-beam scientific echosounders, with the transducers beaming horizontally across the river to provide fish abundance and distribution estimates. Electric fishing surveys provided catch per unit effort estimates and information on size structure and species composition. Catch data from the margins of the study reaches were dominated by roach (Rutilus rutilus), with bleak (Alburnus alburnus) dominant in mid-river. Hydroacoustic data demonstrated patchy spatial distribution, often associated with natural and anthropogenic habitat features. Cyclical peaks and troughs in both hydroacoustic and electric fishing abundance were found. There were periods of correspondence with electric fishing abundance estimates, but also periods of significant divergence. The concept of ‘Shifting Baseline Syndrome’ is discussed with reference to these data, illustrating the importance of viewing long term quantitative information when using meaningful reference points. The potential impact of river temperature and flow on the fish population data are discussed.

Length-weight relationships (LWRs) and length-length relationships (LLRs) were determined for six fish species: Alburnus alburnus, Blicca bjoerkna, Gymnocephalus cernua, Perca fluviatilis, Rutilus rutilus and Sander lucioperca caught using a Nordic multi-mesh gill net in Lake Kirkkojärvi in Southwestern Finland in August 2015. The measurements were done using a photographic method and the dataset is available on the Comprehensive R Archive Network (CRAN). The dataset was done with a scientific catch, which showed lower limits on specimen size than the ones from fisheries. The LWRs were calculated for the total length (TL) and found to be consistent with models from Finland. The length measurements were taken to the nearest 0.01 cm, which also allowed for juveniles to be represented in the model. The goodness of fit of the models is high, with the coefficients of determination above 95%. This study is the first one to estimate LWRs of fish species for this hypereutrophic lake, and is useful for fishery managers and biologists.

The aim of the present study was to detect the antibacterial activity of medicinal plants against fish microflora. A total of 4 ethanolic extracts of 6 plant species were collected from local environments of Slovakia and screened for antibacterial activity against bacterial microflora. Extracts of Melissa officinalis L., Mentha piperita L., Origanum vulgare L. and Malva mauritiana were used. Bacterial strains were isolated from common bleak (Alburnus alburnus) and common rudd (Scardinius erythrophthalmus) of Latvian origin. All bacterial strains were identified with the Matrix- Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS). Among fish microflora, Acinetobacter pittii, A. baumannii, Buttiauxella agrestis, Delftia acidovorans, Enterobacter cloacae, Serratia liquefaciens, Pseudomonas alcaligenes, Ps. oryzihabitans, Staphylococcus epidermidis, St. caprae, Pantoea agglomerans, Lelliottia amnigena, Providencia rettgeri, Escherichia coli and Rahnella aquatilis were identified. It has been shown that all plant extracts exhibit different degrees of antimicrobial activity against the tested bacteria. All bacterial strains in the present study were moderate sensitive to all extracts applied. The strongest antimicrobial effect of Malva mauritiana and Melissa officinalis L. against Pseudomonas oryzihabitans (6.67±1.53 resp. 9.67±0.58 mm) were found. The best antimicrobial activity of Mentha piperita L. was against Staphylococcus epidermis (7.33±0.58 mm) and strongest antimicrobial effect of Origanum vulgare L. was same against two bacterial strains Enterobacter cloacae and Serratia liquefaciens (9.67±0.58 mm).

Historic fisheries data collected from locations across the UK over several years were compared with predicted estrogen exposure derived from the resident human population. This estrogen exposure could be viewed as a proxy for general sewage (wastewater) exposure. With the assistance of the Environment Agency in the UK, fisheries abundance data for Rutilis rutilis (roach), Alburnus alburnus (bleak), Leuciscus leuciscus (dace) and Perca fluviatilis (perch) from 38 separate sites collected over 7 to 17 year periods were retrieved. From these data the average density (fish/m2/year) were compared against average and peak predicted estrogen (wastewater) exposure for these sites. Estrogen concentrations were predicted using the LF2000-WQX model. No correlation between estrogen/wastewater exposure and fish density could be found for any of the species. Year on year temporal changes in roach population abundance at 3 sites on the middle River Thames and 4 sites on the Great Ouse were compared against estrogen exposure over the preceding year. In this case the estrogen prediction was calculated based on the upstream human population providing the estrogen load and the daily flow value allowing concentration to be estimated over time. At none of the sites on these rivers were temporal declines in abundance associated with preceding estrogen (effluent) exposure. The results indicate that, over the past decade, wastewater and estrogen exposure has not led to a catastrophic decline in these four species of cyprinid fish.

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.

The bleak Alburnus alburnus (L., 1758) is a limnophilic fish native to most of Europe. This cyprinid species is a successful invader in the Iberian Peninsula, where it threatens the highly endemic fish fauna. However, studies on bleak autoecology are scarce in this region, with few data on foraging strategies. The aim of this work was to compare the dietary traits of bleak populations between contrasting habitats in Iberian fresh waters. For this purpose, bleak were seasonally collected from the small River Gevora and the Sierra Brava Reservoir (Guadiana River Basin, southwestern Spain). As percentages of occurrence and ingested mass, plant material and planktonic Crustacea were the most important food categories in the river and the reservoir, respectively. The intake of pelagic prey was higher in the reservoir, especially during summer. Benthic prey, plant material and detritus were more consumed in the river, especially benthos and detritus during spring, whereas plant intake decreased during this season. Shannon index, as a measure of trophic diversity, was higher in the reservoir, except for spring. Overall results suggest that this wide trophic plasticity will facilitate the bleak invasion process throughout Mediterranean Europe, which poses a serious risk to its highly valuable native fish fauna.

To inform aquatic conservation policy and management decisions, translocated freshwater fish species, i.e. those native to part but not all of Great Britain (GB), were assessed with the Aquatic Species Invasiveness Screening Kit (AS-ISK) at two spatial levels (River Basin District [RBD] and GB overall), the outcome scores calibrated and analysed to determine the relevance of geographical scale (GB, RBD and freshwater ecoregion) on AS-ISK outcome score rankings. The 16 species assessed received scores that showed limited among-RBD variation, with all but only one species (silver bream Blicca bjoerkna) receiving the same risk ranking across all RBDs for which they were assessed. A trend of increasing AS-ISK score with decreasing RBD latitudinal location was observed, with two species (bleak Alburnus alburnus and tench Tinca tinca) found to have significantly higher AS-ISK scores in west-coast RBDs than in RBDs to the north and east, and one species (bleak Alburnus alburnus) to have significantly higher AS-ISK scores in southern RBDs than in northern RBDs. The Water Framework Directive classification of Scotland was found to be inconsistent with the latitudinal gradients in that country's environmental conditions, which are better reflected in the distinction of northern and southern freshwater ecoregions. The ramifications of these legislative classifications for aquatic conservation are discussed.

Adult stages of digenean flukes are usually well studied, but their larval forms, the metacercariae, do not receive comparable attention of researchers. As a consequence, metacercariae, especially small ones, are routinely overlooked, despite their serious epidemiological and epizootic potential. Therefore, the existing distribution data are patchy and the biogeographic knowledge is far from being complete. We were not able to trace any papers focusing on the depth of penetration of digenean metacercariae in fish tissues. In this study, we were trying to determine the spatial distribution of metacercariae in the muscles of two freshwater cyprinid fishes, the roach, Rutilus rutilus (Linnaeus, 1758) and the bleak, Alburnus alburnus (Linnaeus, 1758). The study area was Lake Dąbie, a large and shallow lake of the Oder (Odra) River estuary, Poland. We studied a total of 40 roach (12.0–21.5 cm TL 30–120 g TW) and 15 bleak (10.5–14.5 cm TL). The fishes were filleted and each filet was divided into four parts. All muscle tissues were examined for the presence of metacercariae using a trichinoscope and a dissecting microscope. Dorsal muscles of an additional 12 roach were sliced and the depth of metacercariae penetration was assessed. The dominant muscle parasite was Paracoenogonimus ovatus. Metacercariae of other species (Posthodiplostomum cuticula and Apophallus muehlingi) were only sporadically found in muscles roach and bleak (with a preference to the shin). The prevalence of Paracoenogonimus ovatus in roach ranged from 66.7% to 100% and the highest infection intensity was 1973 metacercariae in one fish. The infection parameters differed between length classes.

The present contribution is devoted to the Baltic designation of the fish "bleak / Alburnus alburnus" in Lithuanian, Latvian, Prussian toponymy, and in traces of Baltic substrata in North Russian dialects and in Mari from the upper Volga basin. They are studied from the point of view of phonetic history and word formation. Any etymological attempts must be realized together with Slavic counterparts of this Baltic ichthyonym. On the basis of existing etymologies a new solution is proposed, explaining the fish-name with help of one of characteristic features of this fish, golden slime on its scales. The new etymology demonstrates their common origin in the compound *au s- & *kle i o/a - *"gold-slimed" = "fish characterized by its golden slime". This fish-name would further solidify the original Indo-European term for "gold", directly preserved in the Baltic and Italic branches, in another apophonic formation also in Tocharian, but, until now, quite unattested in Slavic.

To date, 22 alien fish species are known in the Ob River basin. Of them, nine species—Pike-perch Sander lucioperca, Freshwater bream Abramis brama, common carp Cyprinus carpio, belica Leucaspius delineatus, bleak Alburnus alburnus, Stone moroko Pseudorasbora parva, Amur sleeper Perccottus glenii, Nikolsky’s loach Misgurnus nikolskyi, and southern ninespine stickleback Pungitius platygaster—formed self-reproducing populations and started self-spreading in natural waterbodies. This paper summarizes the data on invasion of alien fish species in the Ob River basin. The data on history, rate of spread, modern distribution, and relative abundance are given. It is shown that water temperature is the main environmental factor which limits the expansion of introduced species in the Ob basin.

A specimen of late larva of bleak Alburnus alburnus with an additional pair of ventral fins sampled at the middle part of the Saratov Reservoir is described. This type of abnormality was revealed in the Saratov Reservoir for the first time.

The Iberian Peninsula has been subjected to numerous fish introductions and the colonization of new areas by non-native species is constantly reported. However, there is a lack of knowledge about many aspects of the bio-ecology of these species and their invasive success within the environmental context of Mediterranean temporary rivers. This study aimed to address the following questions: (i) what are the main regional and local environmental drivers influencing fish assemblages and differentiating native from non-native species, particularly A. alburnus?, (ii) what are the environmental and anthropogenic disturbance factors responsible for the occurrence and abundance of A. alburnus?, (iii) is there a pattern in the spatiotemporal distribution of A. alburnus size classes, along the tributaries of reservoirs where the species occurs? Data on fish species, environmental variables, and anthropogenic disturbance were collected in 77 sites of the Guadiana and Sado river basins in the south of Portugal. Additionally, a seasonal sampling was performed along an upstream-downstream gradient of several tributaries from three reservoirs in these river basins. A multivariate analysis and a multi-model approach were used in data analyses. Native and non-native fish assemblages showed different environmental drivers and responses to anthropogenic disturbance levels, though A. alburnus has revealed similarities with native species. The occurrence of A. alburnus was mainly determined by hydrological and morphological disturbances driven by anthropogenic activities. Furthermore, this species apparently performed seasonal movements along the tributaries of several reservoirs, profiting from these lentic habitats as a stepping-stone for further invasions. This study highlighted the wide ecological plasticity of A. alburnus, as it benefits from the anthropogenic hydrological disturbance (induced by reservoirs), and is also able to cope with the natural hydrological disturbance (resulting from the intermittency of these streams), to guarantee and enhance its invasive success in Mediterranean intermittent streams. It also gives a sound contribution to understand the spread of A. alburnus in these vulnerable freshwater ecosystems, and to delineate management measures, namely by identifying critical points in the river network along with prioritizing river restoration measures that benefit native species.

The Velika Morava River is the greatest national Serbian river and the significant tributary of the Danube River. The major problems in the Velika Morava River Basin (VMRB) represent untreated industrial and municipal wastewaters. In this study, the level of genotoxic potential at the sites along the VMRB was evaluated by parallel in vitro and in situ approach. Within in vitro testing, genotoxicity of native water samples collected from the sites in VMRB was evaluated by SOS/umuC test on Salmonella typhimurium TA1535/pSK1002 and by the comet assay on HepG2 cells. DNA damage in situ was assessed in bleak (Alburnus alburnus) erythrocytes by the comet (alkaline and Fpg-modified comet) and micronucleus assays. Additionally, the concentration of heavy metals in fish tissue was measured and this data, compiled with the data of the physico-chemical parameters measured in water, was used as a measure of the pollution pressure at the sites. Results showed that applied in vitro tests with native water samples are less sensitive in comparison with in situ tests and should be taken with precaution when making predictions on the status of the ecosystem. Within applied battery of in situ assays differential sensitivity of assays was observed where alkaline comet assay showed the highest potential in differentiation of the sites based on genotoxic potential. Integrated biomarker response showed that usage of the battery of bioassays provides better insight in a genotoxic effects in animals, and consequently, that the holistic approach is more suitable for this type of study.

This study was conducted to determine heavy metals (Cu, Mo, As, Hg) in fish species of Aras River (East Azerbaijan) at four stations (From Julfa to 25km after Nourdos border) during four seasons from 2015 to 2016. Thirty eight specimens of fish were collected by using of electrofishing as the main method for sampling. The amounts of heavy metals were measured by using an atomic spectrophotometer in the muscle tissue of specimens. Bioaccumulation factor was also calculated for each species. The amount of bioaccumulation factor for molybdenum was the highest and the arsenic had the lowest amount. The highest concentration of copper was in Barbus lacerta with a mean of 13.6 ± 11.3μg /g dry weight and for the molybdenum, Alburnoides bipunctatus had the highest mean concentration (11.7±4.9) μg / g dry weight. The average concentration of mercury (13.1 ± 1.5 μg / kg dry weight) was highest in Alburnus alburnus. Regarding the arsenic elements, as it was analyzed in a small number of specimens, the highest concentrations were recorded in Alburnoides bipunctatus. According to ANOVA, there were a significant difference between mean concentration of copper in different species (p

Swimming capacity is a vital function for aquatic organisms because it is essential for obtaining food, reproduction and survival. This is estimated from the critical swimming speed (Ucrit), the maximum metabolic rate (MMR) and the standard metabolic rate (SMR), which can be influenced by the total length (TL), the total weight (BW) and the morphology of the species. These parameters have been analyzed by six species, three cyprinids (Alburnus alburnus, Phoxinus bigerri and Rutilus rutilus), a centrurid (Lepomis gibbosus), and two cyprinodontides (Aphanius iberus and Gambusia holbrooki). The measurements of critical swimming speed (Ucrit), the maximum metabolic rate (MMR) and the standard metabolic rate (SMR) have been obtained experimentally in the laboratory through swimming tunnels coupled to a respirometer. For the morphological measures, we have used the "tpsDig232" program, which can measure areas and perimeters from the photographs of the specimens. The statistical analysis consisted in the application of Covariance Analysis (ANCOVA) between the physiological and morphological variables with the total length and the total weight of the individuals, analysis of the Variance (ANOVA) when there was no linear regression between the variables physiological and morphological factors with total length and total weight and, also, an analysis of correlations between the physiological and morphological variables. Finally, we have used the Analysis of Main Components (PCA) for all the species and the variables studied. The results obtained showed an increase in Ucrit as the total length increases and an inversely proportional relationship between Ucrit and MMR. MMR and SMR have been found to be related to total weight so that individuals with higher weight present higher oxygen (mg O2/h) intake. High values of Fineness ratio, Aspect ratio, Propulsive ratio and Caudal peduncle factor are determinants of hydrodynamic morphology of species, and therefore they were related with the Ucrit, the MMR and the SMR. High values of Muscle ratio have been observed in non-migratory species which showed low Ucrit. Furthermore, high values of Aspect ratio have been observed in migratory species which showed a high Ucrit. The life style of the species and its morphology seemed to play a key role in determining the swimming capacity (Ucrit) and metabolic rates (MMR and SMR) of the species studied

Background. Freshwater fishes are among the most threatened taxa worldwide. The proliferation of introduced species in the Iberian Peninsula is currently one of the main drivers of native fish declines. One of such species, the bleak, Alburnus alburnus (Linnaeus, 1758), has become widespread in the last 25 years and, due to its phylogenetic proximity, poses a high risk of hybridization with native species. The aim of this study was to improve the current knowledge on this issue by 1) evaluating the presence of hybrids with Alburnus alburnus in the wild, using molecular screening of individuals representing the intermediate morphology and 2) testing if artificial crosses between Alburnus alburnus and the highly threatened native cyprinid Anaecypris hispanica (Steindachner, 1866) resulted in viable hybrid offspring. Materials and methods. The genetic profile of Alburnus alburnus was established using the cytochrome b and beta-actin genes to allow comparisons with the profiles of the sympatric species with which it could potentially hybridize: Anaecypris hispanica; Squalius alburnoides (Steindachner, 1866); and Squalius pyrenaicus (Günther, 1868). This profile was further used to assess if fish with the intermediate morphological features were indeed hybrids. Finally, artificial crosses between Alburnus alburnus and Anaecypris hispanica were conducted to test the viability of the offspring. Results. Alburnus alburnus individuals were genetically identical to the stocks introduced in Spain and the Czech Republic. A reference library composed of 15 species-specific nDNA loci was built and used to characterize wild fish showing intermediate morphological features. Results showed that Alburnus alburnus is currently hybridizing with males and females of Squalius alburnoides and that morphometric identification is insufficient for a reliable detection of the hybrids. Artificial crosses between the bleak and the highly threatened Anaecypris hispanica did not result in viable offspring. Conclusion. Phylogenetic relatedness, traduced in the absence of pre- and post-zygotic barriers to reproduction, together with other factors related to the ecology and life history of the species involved are essential for hybridization to occur. As such, the proliferation of the bleak through the Iberian hydrographical network represents a serious additional threat for the already imperilled native Squalius and Anaecypris species.

A hybrid Leuciscus leuciscus × Alburnus alburnus was found during the ichthyofaunistic studies in the Bystrzyca River, a left-bank tributary of the Odra River (SW Poland). The hybrid was identified on the basis of its intermediate features and characteristics of the parent species (biometrical, osteological and anatomical) such as opercular and dental bones, pharyngeal bones and teeth, shape of scales, number, form and structure of radial canals of the scales, and air bladder and a complex of meristic and morphometric characters. With respect to its characteristics, the hybrid is closer to dace than to bleak. The small abundance of the hybrid shows that the hybridisation was rather accidental.

The Sava River Basin is under strong impact of stressors related to anthropogenic activity, yet the consequences that the stressors might have on aquatic biota are not properly addressed. This dissertation aims to provide data on genotoxic potential along the Sava River. Research was organized in two campaigns. In the first campaign, preliminary research was conducted to indicate optimal bioindicator, season, sample preservation and bioassays for performing the research on the scale of the whole Sava River. The second campaign consists of comprehensive survey along the 900 rkm of the Sava River. With combined in vivo and in vitro approach, 12 sites were analyzed in total. The genotoxic potential was assessed using a complex battery of bioassays performed in prokaryotes and aquatic eukaryotes (freshwater fish). Battery comprised evaluation of mutagenicity by SOS/umuC test in Salmonella typhimurium TA1535/pSK1002. The level of DNA damage as a biomarker of exposure (comet assay) and biomarker of effect (micronucleus assay) and the level of oxidative stress as well (Fpg - modified comet assay) was studied in blood cells of bleak and spirlin (Alburnus alburnus/Alburnoides bipunctatus respectively). Results indicated differential sensitivity of applied bioassays in detection of genotoxic pressure. Comet assay showed higher potential in differentiation of the sites based on genotoxic potential in comparison with other assays. Data presented in this dissertation are a snapshot of the current status of the river. Genotoxic potential along the river can be traced to the deterioration of water quality by communal and industrial wastewaters. The major highlight of the study is that the complex set of data was obtained from a single source (homogeneity of analyses for all samples). Слив реке Саве је под снажним утицајем стресора антропогеног порекла, међутим последице које стресори могу имати на водену биоту нису довољно испитане. Ова дисертација има за циљ да испита генотоксични потенцијал дуж реке Саве. Истраживање је организовано у две целине. У овиру прве целине испитивало се који биоиндикаторски организам је оптималан за истраживање на нивоу читаве реке. Такође испитивао се утицај сезоне на одговор биомаркера као и методологија очување узорка на резултате анализа. У оквиру друге целине рађено је комплексно истраживања дуж 900 ркм реке Саве. Коришћен је комбиновани in vivo и in vitro приступ, при чему је анализирано укупно 12 локација. Генотоксични потенцијал је праћен употребом сложене батерије биотестова на прокариотским и еукариотским организимима. Батерија је обухватала процену мутагеног потенцијала SOS/umuC тестом на бактерији Salmonella typhimurium TA1535/pSK1002. Ниво оштећења ДНК, као биомаркер излагања (кометни тест) и биомакер ефекта (микронуклеус тест) као и ниво оксидативног стреса (Fpg - модификовани кометни тест) праћен је у крвним ћелијама риба (Alburnus alburnus/Alburnoides bipunctatus). Резултати су показали различиту осетљивост примењених биолошких тестова у детекцији генотоксичног потенцијала. Комет тест је имао већи потенцијал у диференцирању локалитета по генотоксичном потенцијалу у поређењу са другим примењеним тестовима. Подаци представљени у овој дисертацији представљају слику тренутног стања реке. Генотоксични потенцијал забележен дуж реке се може везати за нарушен квалитет воде утицајем комуналних и индустријских отпадних вода. Подаци приказани у овој студији потичу из јединственог извора (хомогеност анализа за све узорке) упркос великој географској површини коју студија покрива што јој додатно даје на значају.

Alburnus alburnus (Linnaeus, 1758), Bleak Cyprinus alburnus Linnaeus 1758: 325. Alburnus alburnus — Kottelat and Freyhof 2007: 164. Material examined. Table 1; Fig. 7C. Presence of 45–48+3 lateral line scales; 17–20 branched anal-fin rays; and 16–22 gill rakers on first gill arch. It is an abundant species and is absent only in ponds; recorded in all sampled rivers at a distance of 26 to 500 km from the source. In upstream sections of rivers (up to 25 km from the source), its occurrence rate was 28.2%; in other water bodies, the rate varied from 16.1% in landlocked oxbows to 37.5% in flowing oxbows. The percentage of A. alburnus in catches increase with the size of the river, reaching 40% in sections of river between 200 and 500 km from the source. Its abundance in other water bodies is considerably smaller, about 1–9.1%., Published as part of Artaev, Oleg & Ruchin, Alexander B., 2017, The ichthyofauna of the Moksha River, a tributary of the Volga river basin, Russia, pp. 185-202 in Check List 13 (4) on page 193, DOI: 10.15560/13.4.185, {"references":["Linnaeus C (1758) Systema naturae per regna tria naturae: secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis, ed. 10. Laurentii Salvii, Holmiae, 824 pp. https: // doi. org / 10.5962 / bhl. title. 542","Kottelat M, Freyhof J (2007) Handbook of European Freshwater Fishes. The authors, Cornol / Berlin, 646 pp."]}

Predator-prey relationships are often perceived simply as a situation in which a predator enhances its own fitness while reducing the fitness of its prey. However, this relationship may become reversed when the prey feeds on the juvenile predator stages. We investigated this phenomenon in a model asp (Leuciscus aspius; predator)-bleak (Alburnus alburnus; prey) relationship. The adhesive asp eggs are available for bleak predation after a spawning event for only tens of seconds before they adhere to the stones, where bleak do not forage. Gut content analysis demonstrated that eggs were utilized in high quantities, especially in the spawning peak of the asp reproductive season. Furthermore, using underwater video, we recorded the bleak feeding efficiency on naturally drifting asp eggs as the percentage of eggs eaten. Within the 40 cm egg trajectory captured by our cameras, total egg mortality was 21.2 ± 2.2% on average. The highest survival chances occurred among eggs drifting in aggregations, since the short drifting distance together with their aggregated distribution satiated bleak and part of the egg aggregation could attach to the spawning ground. This study emphasizes the potential efficiency of predator egg utilization by prey, which may have further consequences in predator-prey dynamics.

Besides food quality control of fish or cephalopods, the novel mass spectrometry (MS) approaches could be effective and beneficial methods for the investigation of biodiversity in ecological research. Our aims were to verify the applicability of MALDI-TOF MS in the rapid identification of closely related species, and to further develop it for sex determination in phenotypically similar fish focusing on the low mass range. For MALDI-TOF MS spectra analysis, ClinProTools software was applied, but our observed classification was also confirmed by Self Organizing Map. For verifying the wide applicability of the method, brains from invertebrate and vertebrate species were used in order to detect the species related markers from two mayflies and eight fish as well as sex-related markers within bleak. Seven Ephemera larvae and sixty-one fish species related markers were observed and nineteen sex-related markers were identified in bleak. Similar patterns were observed between the individuals within one species. In contrast, there were markedly diverse patterns between the different species and sexes visualized by SOMs. Two different Ephemera species and male or female fish were identified with 100% accuracy. The various fish species were classified into 8 species with a high level of accuracy (96.2%). Based on MS data, dendrogram was generated from different fish species by using ClinProTools software. This MS-based dendrogram shows relatively high correspondence with the phylogenetic relationships of both the studied species and orders. In summary, MALDI-TOF MS provides a cheap, reliable, sensitive and fast identification tool for researchers in the case of closely related species using mass spectra acquired in a low mass range to define specific molecular profiles. Moreover, we presented evidence for the first time for determination of sex within one fish species by using this method. We conclude that it is a powerful tool that can revolutionize ecological and environmental research.

The moisture content of β-cyclodextrin/Danube fish oils complexes (common barbel, Pontic shad, European wels catfish, common bleak) was evaluated by thermal methods. Saturated and monounsaturated fatty acids were the most concentrated in fish oils (25.3–30.8% and 36.1–45.0%). ω-3 And ω-6 fatty acids were identified in low concentrations of 2.8–12.1% and 4.1–7.1%. The moisture content was significantly lowered after β-CD complexation, as revealed by thermogravimetric (TG) analysis (13.3% for β-CD, 2.5–6.5% for complexes). These results are consistent with the differential scanning calorimetry (DSC) data for the peaks corresponding to dissociation of water (calorimetric effect of 536 J g −1 for β-cyclodextrin and 304–422.5 J g −1 for complexes). Furthermore, both TG and DSC results support the formation of inclusion complexes. This is the first study on the nanoencapsulation of Danube fish oils in β-cyclodextrin.

Dužinsko-maseni odnosi i dužinsko-dužinski odnosi određeni su za šest vrsta riba: ukliju (Alburnus alburnus), krupaticu (Blicca bjoerkna), balavca (Gymnocephalus cernua), grgeča (Perca fluviatilis), bodorku (Rutilus rutilus) i smuđa (Sander lucioperca) ulovljenih pomoću nordijske mreže s više manjih mreža u jezeru Kirkkojärvi u jugozapadnoj Finskoj u kolovozu 2015. godine. Mjerenja su provedena pomoću fotografske metode i skup podataka je dostupan na Comprehensive R Archive Network (CRAN). Podaci su dobiveni znanstvenim ulovom koji je pokazao niže granice veličine uzoraka od onih iz ribarstva. Dužinsko-maseni odnosi su izračunati za totalnu dužinu te je utvrđeno da su u skladu s podacima iz Finske. Mjerenje dužine odvijalo se na najbližu dužinu od 0,01 cm, što je omogućilo da i mlađ bude zastupljena u modelu. Sposobnost prilagodbe modelu je visoka, s koeficijentom determinacije većim od 95%. Ovo istraživanje je prvo koje procjenjuje dužinsko-masene odnose ribljih vrsta za ovo hipereutrofno jezero i korisno je za ribarsku proizvodnju i biologe., Length-weight relationships (LWRs) and length-length relationships (LLRs) were determined for six fish species: Alburnus alburnus, Blicca bjoerkna, Gymnocephalus cernua, Perca fluviatilis, Rutilus rutilus and Sander lucioperca caught using a Nordic multi-mesh gill net in Lake Kirkkojärvi in Southwestern Finland in August 2015. The measurements were done using a photographic method and the dataset is available on the Comprehensive R Archive Network (CRAN). The dataset was done with a scientific catch, which showed lower limits on specimen size than the ones from fisheries. The LWRs were calculated for the total length (TL) and found to be consistent with models from Finland. The length measurements were taken to the nearest 0.01 cm, which also allowed for juveniles to be represented in the model. The goodness of fit of the models is high, with the coefficients of determination above 95%. This study is the first one to estimate LWRs of fish species for this hypereutrophic lake, and is useful for fishery managers and biologists.

Desert rivers are highly dynamic systems in which dry periods, frequently involving the cessation of superficial flow, alternate with violent flash floods. In spite of their territorial importance and high functional and biological diversity, desert rivers have received little attention in the scientific literature, especially in Northern Africa. This study investigated the distribution of non-native fish, their relationship with river damming and their potential impacts on native biodiversity in the main river basins draining arid areas of Morocco (Oued Draa, Oued Ziz and Oued Ghir), based on field sampling covering 84 stream reaches. Thirteen fish species were recorded, eight of which are non-native. Two species (stone moroko, Pseudorasbora parva, and bleak, Alburnus alburnus) had not been previously recorded in Morocco, while the native sandsmelt (Atherina boyeri) had not been cited as an invader. Pumpkinseed (Lepomis gibbosus) was the most widely distributed non-native fish. Non-native fish species were associated with reservoirs, colonizing the regulated downstream reaches. In contrast, unregulated upstream reaches tended to be free of non-natives. The low abundance of native fish in reservoirs seems to be caused by the impacts of introduced fish species. Management options for environmental flow are limited, owing to reduced water availability. Non-native fish management should thus focus on limiting the spread of species already introduced and avoiding new introductions, especially into reservoirs. Copyright © 2014 John Wiley & Sons, Ltd.

The aim of the study was to determine the degree of overlap in the feeding niches of early developmental stages of roach, Rutilus rutilus (L.), perch, Perca fluviatilis L., bleak, Alburnus alburnus (L.) and sunbleak, Leucaspius delineatus (Heckel). The hypotheses were that (i) larvae of different fish species of similar body sizes feed on similar food, and that (ii) smaller fish compete with larger ones for similar prey. The results of the analysis was to answer the question of whether the diet overlap of juvenile fish stages decreases with ontogenetic development. The study was conducted for two years (2001-2002) in two shallow, polymictic, eutrophic lakes. The diets of early developmental stages of fish species of similar body sizes differed. The few instances of diet overlap resulted from the abundance of food resources in the environment. However, fish of smaller body sizes exploited the same food resources as did individuals of the same species that belonged to different cohorts.