Fundamental and Applied Limnology / Archiv für Hydrobiologie, 2015
Reliable estimation of the diet composition of filter-feeding Asian carps is essential to evaluat... more Reliable estimation of the diet composition of filter-feeding Asian carps is essential to evaluate their effects on ecosystem functioning. In previous studies, the diet composition of these fishes was primarily determined based on the analysis of foregut contents. To assess the reliability of foregut content analysis in diet assessments, these were compared with gill raker filtrate analyses. Gill raker filtrates were found to be more reliable than foregut contents for determining food composition due to higher amounts of sample, significantly higher numbers of identifiable taxa (including both phytoplankton and zooplankton), and considerably higher numbers of intact planktonic individuals. The present findings indicate that diet composition analyses based on foregut samples alone are likely to underestimate the number of individuals and the biomass of planktonic species which are less resistant to digestive processes.
Distance-based morphometry is still widely used in ichthyology. Beside others, this methodology i... more Distance-based morphometry is still widely used in ichthyology. Beside others, this methodology is often used to characterise species or to compare intraspecific group (i.e. population level) differences. However, scarce information is available about: (a) which are the most widely used variables for these purposes, (b) how certain variables are selected for the morphometric analyses, and (c) how variable set compositions and the number of variables affect the results. To answer these questions, a literature review was compiled and our own three datasets were analysed. The results showed that although a high number of variables can be used, previous authors have measured “common” ones most often, regardless of the taxonomic position of the studied group and the goal of the survey. Additionally, our review showed that authors rarely made a variable selection and often did not standardise their datasets; these are methodical problems that make the accuracy and usability of the results...
Several recent notes prove that taxonomic relations of close relative animal groups (species comp... more Several recent notes prove that taxonomic relations of close relative animal groups (species complexes or cryptic species) can be revealed by the combined use of genetic and morphologic methodologies. At the same time scarce information can be found about how phylogeny, population origin, and sexual dimorphism affect the morphometric features of these species. In our present work, we performed simultaneous phylogenetic and morphological studies on the taxonomically still questionable Carpathian stream dwelling gudgeons (Cyprinidae, Gobio) by using two different methodologies (distance based and geometric morphometry). Our results were in correspondence with the previous findings, showing the presence of three phylogenetically more or less distinct groups in the area. The results of the whole-body geometric and the traditional, distance-based morphometry reflected the extent of phylogenetic differences. While the results of geometric scale morphometry did not correspond with the gene...
Kivonat: Jelen munkánkban 1) szakirodalmi közléseket felhasználva történeti áttekintést nyújtunk ... more Kivonat: Jelen munkánkban 1) szakirodalmi közléseket felhasználva történeti áttekintést nyújtunk az idegenhonos halfajok magyarországi folyóvizekben való megjelenéséről; 2) az utóbbi öt évben végzett országos léptékű halállomány felméréseink eredményeit térinformatikai módszerrel elemezve országos és Balatoni vízgyűjtő szintjén bemutatjuk e halfajok recens elterjedés mintázatát, és relatív abundancia adatait. Valamint 3) vizsgáljuk a tengerszint feletti magasság és a halastavak idegenhonos fajok elterjedés mintázatára gyakorolt hatásait. Magyarországi természetes vizekből 60 idegenhonos halfaj és hibrid előfordulásáról találtunk tudományos közléseket. A közlési időpontok alapján elmodható, hogy utóbbi években az előkerült idegenhonos fajok száma egyre növekszik. Ezt támasztja alá az a tény is, hogy a fajok túlnyomó részét (48) az utóbbi öt évben is jelezték természetes vizeinkből. A terepi vizsgálataink során felmért 767 vízfolyásszakasz 78,7%-ról mutattuk ki idegenhonos fajok egyedeit. A felmérések során fogott fajok 28,8%-át, illetve a fogott összegyedszám 18,27%-át az idegenhonos halak adták. A kis-és közepes vízfolyásokban az ezüstkárász, a kínai razbora és a naphal voltak a leggyakoribb idegenhonos fajok. Itt az elterjedési mintázatokat és relatív abundancia viszonyokat elsősorban a tengerszint feletti magasság, valamit a halastavak jelenléte-hiánya, illetve azok relatív helyzete befolyásolta. Nagyobb vízfolyásokban a gébfélék a domináns idegenhonos fajok. Az országos adatokkal összevetve a balatoni vízgyűjtőn fokozottabban terhelt inváziós fajokkal. Ugyanakkor az idegenhonos fajok vízgyűjtőn tapasztalt elterjedés-intázata arra utal, hogy nem elsősorban a tavak megléte, hanem inkább azok üzemrendje lehet az a tényező, ami döntően befolyásolja a környezetükben lévő vízfolyásszakaszok idegenhonos fajokkal való fertőzöttségét. Véleményünk szerint a klímaváltozás miatt újabb spontán terjedő idegenhonos fajok megjelenésére mindenképpen számítanunk kell a közeljövőben. Ugyanakkor az emberi segítséggel terjedő fajok további térnyerése jelentősen lassítható lenne, az akvarisztikai célú halkereskedelem, a horgásztavi telepítések, illetve a vízgyűjtőket átszelő halastavak közti halszállítmányozás fokozottabb ellenőrzésével.
Background Invasive gibel carp, Carassius gibelio (Bloch, 1782) has become well-established in th... more Background Invasive gibel carp, Carassius gibelio (Bloch, 1782) has become well-established in the Hungarian waters and now are spreading in the European waters. On major concern now is the potential hybridization between gibel carp and the other invasive species in the Carassius auratus complex (CAC), which may further accelerate the spread of the whole invasive species complex. The identification of gibel carp and their hybrids is difficult because of its morphological similarity to the other species in CAC. Here we carry out a genomic assessment to understand the history of gibel carp invasion and its phylogenetic relationship with the other species in CAC. Three loci of the mitochondrial genome (D-loop, CoI, Cytb) were used to determine the phylogenetic origin of individuals and relarionship among six gibel carp populations and the other species in the CAC. Methodolgy A total of 132 gibel carp samples from six locations in Southern Transdanubia (Hungary) were collected after phe...
Recent researches suggest that functional diversity represents the response of communities to env... more Recent researches suggest that functional diversity represents the response of communities to environmental alterations better than taxonomic diversity. However, there is scarce information about how the functional diversity of freshwater fishes is affected by habitat type and the dominance of non-native species. To address this question, we analysed a large database containing 15 morpho-functional traits of 61 fish species from the Pannon Biogeographic region (Hungary). Based on a fish faunistic list and relative abundance of taxa, we quantified the taxonomic and functional diversity of riverine communities for > 700 sites of six habitat types. We asked how non-native fishes affected the taxonomic and functional diversity in different river types and at the local scale (i.e. at the site level), and how the diversity measures of native fauna elements changes along the invasion gradient. Our results showed that both functional and taxonomic richness increases with habitat complexi...
In this study, we provide the first genetically verified distribution record of Ligula pavlovskii... more In this study, we provide the first genetically verified distribution record of Ligula pavlovskii, a high-impact endoparasite of Ponto-Caspian gobies, beyond its native range. According to parasitological surveys, ligulosis was detected for the first time in monkey goby individuals collected from Lake Balaton in 2004, 34 years after the first record of monkey goby in the lake. During a Lake Balaton survey in 2018, we detected tapeworms in 44.4% of the sampled monkey gobies. This prevalence is about two to ten times higher than it was reported from within the native range of the fish hosts. The same survey revealed an uneven spatial distribution of the ligulosis in the monkey gobies inhabiting different shoreline sections of the lake. We assume that the occurrence and recent distribution data of this high-impact endoparasite may provide useful information for potential biocontrol measures of invasive Ponto-Caspian gobies in the future.
Knowledge of intraspecific variability of a certain species is essential for their long-term surv... more Knowledge of intraspecific variability of a certain species is essential for their long-term survival and for the development of conservation plans. Nowadays, molecular/genetic methods are the most frequently used for this purpose. Although, the Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) technique has become a promising alternative tool to specify intraspecific variability, there is a lack of information about the limitations of this method, and some methodological issues need to be resolved. Towards this goal, we tested the sensitivity of this method on an intraspecific level, using genetically identified individuals of a cryptic fish species complex collected from five distinct populations. Additionally, some methodologic issues, such as the effect of (1) delayed sample preparation, (2) clove oil anaesthetization, and (3) different tissue types (muscle, and brain) were investigated using the MS analysis results. Our results show tha...
Detailed knowledge on the habitat preference of invasive fishes and the bias of different fishing... more Detailed knowledge on the habitat preference of invasive fishes and the bias of different fishing methods in determining their population dynamic parameters are essential in fisheries management, ecology and conservation. This study was conducted to determine the habitat use and length frequency distribution of the invasive monkey goby and pumpkinseed in the littoral zone of Lake Balaton (Hungary) using two different sampling methods, electrofishing and fyke netting. In general, both species preferred anthropogenically modified habitat types (rip-rap shorelines and harbours) compared with natural reed habitats with silty-sand bottom. Length frequency distribution data showed significant between-gear differences, since electrofishing resulted in the capture of larger individuals in greater proportion than fyke nets for both species. This study, which includes the first detailed data about the habitat use of the highly invasive monkey goby in lakes, suggests that invasive species may benefit from the alteration of the littoral zone. It also highlights that reliance on single gear surveys can be misleading in assessing habitat use and population structure of invasive fishes.
Environmental Engineering and Management Journal, 2016
We examined the effluent from a municipal (Nyíregyháza, Hungary) wastewater treatment plant (WWTP... more We examined the effluent from a municipal (Nyíregyháza, Hungary) wastewater treatment plant (WWTP) on hydrophysicochemical properties and on diversity, community structure, and stability of fish assemblages at the recipient low flow channel system during a two-year period. The WWTP outflow increased significantly the nutrient concentrations (e.g. NO2 and NO3 concentrations increased to 4x and 8x respectively), and the regime (with the permanent ~0.23m 3 /s load) at the recipient channel sections. The wastewater outflow not only altered, but stabilized the physico-chemical variables measured, and the water regime in the recipient channels. Thus the natural, periodic fluctuation of the environmental variables was diminished in the study period. The WWTP outflow caused significant changes in the fish fauna as well. High abundances and taxa richness were found in the stocks inhabiting the charged watercourse sections. At the same time, species composition and relative abundances of fish stocks proved to be more constant at the impaired sites. Our results show that the WWTP outflow caused altered, but significantly more stable environmental conditions. These alterations were favourable for the emergence of a more diverse and more stable fish community on the recipient channel sections. Hence, the dynamic variability in fish assemblage structure that is characteristic of natural lowland stream was not apparent in these perturbed, semi natural habitats.
Quantifying the relative importance of how local (environmental or niche‐based) and regional (dis... more Quantifying the relative importance of how local (environmental or niche‐based) and regional (dispersal‐related or spatial) processes regulate the assembly of communities has become one of the main research avenues of community ecology. It has been shown that the degree of isolation of local habitats in the landscape may substantially influence the relative role of environmental filtering and dispersal‐related processes in metacommunities. Dendritic stream networks are unique habitats in the landscape, where more isolated upstream sites have been predicted to be primarily structured by environmental variables, while more central mainstem rivers by both environmental and spatial variables (hereafter the network position hypothesis, NPH). However, the NPH has almost exclusively been tested for stream macroinvertebrates, and therefore its predictions warrant confirmation from multiple taxa. We examined the validity of the NPH for benthic diatoms, macrophytes, macroinvertebrates and fis...
Due to its central position in the Danube basin and its considerable fishery sector, Hungary play... more Due to its central position in the Danube basin and its considerable fishery sector, Hungary plays a key role in the spread of non-native fish species in Europe. Nevertheless, the status of non-native fish has not yet been reviewed for Hungary. Therefore, our aims were 1) to give a comprehensive historical overview regarding the occurrence of non-native fish species of Hungary, 2) to show their recent distribution patterns using GIS, and 3) to evaluate the importance of the possible drivers in their spread. Literature data show 59 non-native fish species from Hungary. The appearance of new species-mostly due to aquarium fish releasesshows an accelerating trend nowadays. Although non-native fish have appeared at 78.7% of the studied 767 sites during our recent countrywide survey, their distribution was uneven. Lowland streams, lowland rivers, and the River Danube were the most affected by non-native fish, particularly the gibel carp, topmouth gudgeon and pumpkinseed escaped from fish/angling ponds, and the recent invasion of Ponto-Caspian gobies. Our results indicated that in order to reduce the effects and intensity of further invasions, more rigorous control of aquarium trade, angling pond stockings, and inter-watershed fish transports are necessary. keywords: invasion, invasive species, fisheries, aquarium trade, ecological risks, Carpathian basin Fish faunistic surveys were made within the frame of the following projects: OTKA CNK80140, OTKA K104279, OTKA PD115801, and a KEHOP2015 project of the General Directorate of Water Management. We would like to express our thanks to colleagues at the General Directorate of Water Management, but Gy. I. Tóth and T.A. Zagyva for their help in several phases of the work. Data analysis was supported by the GINOP 2.3.2-15-2016-00004 project. Árpád Ferincz was supported by the Bolyai Fellowship of the Hungarian Academy of Sciences.
Running head: fish metacommunities in stream networks types in riverscapes, and niche based speci... more Running head: fish metacommunities in stream networks types in riverscapes, and niche based species sorting mechanisms are more influential in their structuring than dispersal ones. Landscape classifications are useful for a better understanding of the structuring of metacommunities in both the freshwater and the terrestrial realm.
The genetic structure of European mudminnow populations throughout the species range was examined... more The genetic structure of European mudminnow populations throughout the species range was examined using mitochondrial DNA and seven microsatellite loci. Ten mitochondrial haplotypes were detected, suggesting three phylogeographic lineages, which likely diverged during the Early and Middle Pleistocene. These three lineages geographically correspond to three regions: the Danube drainage including the Drava system and Dniester Delta, the Sava system, and the Tisza system. High genetic diversity observed using mtDNA was confirmed with microsatellite data, suggesting the existence of 14 populations in the studied area. The isolation-with-migration model showed that migration rates between populations were generally low, and were highest between the Drava and its tributary Mura. According to the inferred relative population splitting times, U. krameri likely spread from the eastern part of the species range to the west, which also showed the highest genetic diversity and largest population size. As reported by the time-calibrated phylogeny, separation of the European and American Umbra occurred roughly at the end of Late Cretaceous and in the first half of the Paleogene (60.57 Ma with 95% highest probability density of 39.57-81.75). Taking these results into account, appropriate guidelines are proposed to conserve European mudminnow populations.
We compared the repeatability, reproducibility (intra-and inter-measurer similarity), separative ... more We compared the repeatability, reproducibility (intra-and inter-measurer similarity), separative power and subjectivity (measurer effect on results) of four morphometric methods frequently used in ichthyological research, the "traditional" caliper-based (TRA) and trussnetwork (TRU) distance methods and two geometric methods that compare landmark coordinates on the body (GMB) and scales (GMS). In each case, measurements were performed three times by three measurers on the same specimen of three common cyprinid species (roach Rutilus rutilus (Linnaeus, 1758), bleak Alburnus alburnus (Linnaeus, 1758) and Prussian carp Carassius gibelio (Bloch, 1782)) collected from three closely-situated sites in the Lake Balaton catchment (Hungary) in 2014. TRA measurements were made on conserved specimens using a digital caliper, while TRU, GMB and GMS measurements were undertaken on digital images of the bodies and scales. In most cases, intra-measurer repeatability was similar. While all four methods were able to differentiate the source populations, significant differences were observed in their repeatability, reproducibility and subjectivity. GMB displayed highest overall repeatability and reproducibility and was least burdened by measurer effect. While GMS showed similar repeatability to GMB when fish scales had a characteristic shape, it showed significantly lower reproducability (compared with its repeatability) for each species than the other methods. TRU showed similar repeatability as the GMS. TRA was the least applicable method as measurements were obtained from the fish itself, resulting in poor repeatability and reproducibility. Although all four methods showed some degree of subjectivity, TRA was the only method where population-level detachment was entirely overwritten by measurer effect. Based on these results, we recommend a) avoidance of aggregating different measurer's datasets when using TRA and GMS methods; and b) use of image-based methods for morphometric surveys. Automation of the morphometric workflow would also reduce any measurer effect and eliminate measurement and data-input errors.
Risk assessment of non-native fishes in the catchment of the largest Central-European shallow lak... more Risk assessment of non-native fishes in the catchment of the largest Central-European shallow lake (Lake Balaton, Hungary).
The European mudminnow (Umbra krameri) is a Middle Danubian endemic fish species, which is charac... more The European mudminnow (Umbra krameri) is a Middle Danubian endemic fish species, which is characterised by isolated populations living mainly in artificial habitats in the centre of its range, in the Carpathian Basin. For their long term preservation, reliable information is needed about the structure of stocks and the level of isolation. The recent distribution pattern, and the population genetic structure within and among regions were investigated to designate the Evolutionary Significant, Conservation and Management Units (ESUs, CUs, MUs) and to explore the conservation biological value of the shrinking populations. In total, eight microsatellite loci were studied in 404 specimens originating from eight regions. The results revealed a pronounced population structure, where strictly limited gene flow was detected among regions, as well as various strengths of connections within regions. Following the results of hierarchical structure analyses, two ESUs were supposed in the Carpat...
Present study established correlations between the spatial distribution of three stream-dwelling ... more Present study established correlations between the spatial distribution of three stream-dwelling fish species (chub, stone loach and gudgeon), the environmental variables which affect their distribution, and the genetic structure of their assemblages, in a North Hungarian drainage system. The spatial distribution of gudgeon and stone loach (which have more specific habitat needs) was affected by elevation, slope and distance from the mouth. Chub occurred frequently in the wider and deeper streams of the hills with higher velocity, but was repeatedly caught in lowland situated sections close to the mouth as well. Genetic data obtained with AFLP were correlated with distribution and as a result higher genetic distances were revealed among gudgeon and stone loach than among chub assemblages. The assemblages of the former two species show a clear pattern of isolation by distance. Results suggest that lowland sections of the studied streams might act as ecological barriers for stone loach and gudgeon assemblages, but not for the chub. Hence, in this drainage system the stone loach and gudgeon appear with separated populations while the chub is characterized by a metapopulation structure.
Fundamental and Applied Limnology / Archiv für Hydrobiologie, 2015
Reliable estimation of the diet composition of filter-feeding Asian carps is essential to evaluat... more Reliable estimation of the diet composition of filter-feeding Asian carps is essential to evaluate their effects on ecosystem functioning. In previous studies, the diet composition of these fishes was primarily determined based on the analysis of foregut contents. To assess the reliability of foregut content analysis in diet assessments, these were compared with gill raker filtrate analyses. Gill raker filtrates were found to be more reliable than foregut contents for determining food composition due to higher amounts of sample, significantly higher numbers of identifiable taxa (including both phytoplankton and zooplankton), and considerably higher numbers of intact planktonic individuals. The present findings indicate that diet composition analyses based on foregut samples alone are likely to underestimate the number of individuals and the biomass of planktonic species which are less resistant to digestive processes.
Distance-based morphometry is still widely used in ichthyology. Beside others, this methodology i... more Distance-based morphometry is still widely used in ichthyology. Beside others, this methodology is often used to characterise species or to compare intraspecific group (i.e. population level) differences. However, scarce information is available about: (a) which are the most widely used variables for these purposes, (b) how certain variables are selected for the morphometric analyses, and (c) how variable set compositions and the number of variables affect the results. To answer these questions, a literature review was compiled and our own three datasets were analysed. The results showed that although a high number of variables can be used, previous authors have measured “common” ones most often, regardless of the taxonomic position of the studied group and the goal of the survey. Additionally, our review showed that authors rarely made a variable selection and often did not standardise their datasets; these are methodical problems that make the accuracy and usability of the results...
Several recent notes prove that taxonomic relations of close relative animal groups (species comp... more Several recent notes prove that taxonomic relations of close relative animal groups (species complexes or cryptic species) can be revealed by the combined use of genetic and morphologic methodologies. At the same time scarce information can be found about how phylogeny, population origin, and sexual dimorphism affect the morphometric features of these species. In our present work, we performed simultaneous phylogenetic and morphological studies on the taxonomically still questionable Carpathian stream dwelling gudgeons (Cyprinidae, Gobio) by using two different methodologies (distance based and geometric morphometry). Our results were in correspondence with the previous findings, showing the presence of three phylogenetically more or less distinct groups in the area. The results of the whole-body geometric and the traditional, distance-based morphometry reflected the extent of phylogenetic differences. While the results of geometric scale morphometry did not correspond with the gene...
Kivonat: Jelen munkánkban 1) szakirodalmi közléseket felhasználva történeti áttekintést nyújtunk ... more Kivonat: Jelen munkánkban 1) szakirodalmi közléseket felhasználva történeti áttekintést nyújtunk az idegenhonos halfajok magyarországi folyóvizekben való megjelenéséről; 2) az utóbbi öt évben végzett országos léptékű halállomány felméréseink eredményeit térinformatikai módszerrel elemezve országos és Balatoni vízgyűjtő szintjén bemutatjuk e halfajok recens elterjedés mintázatát, és relatív abundancia adatait. Valamint 3) vizsgáljuk a tengerszint feletti magasság és a halastavak idegenhonos fajok elterjedés mintázatára gyakorolt hatásait. Magyarországi természetes vizekből 60 idegenhonos halfaj és hibrid előfordulásáról találtunk tudományos közléseket. A közlési időpontok alapján elmodható, hogy utóbbi években az előkerült idegenhonos fajok száma egyre növekszik. Ezt támasztja alá az a tény is, hogy a fajok túlnyomó részét (48) az utóbbi öt évben is jelezték természetes vizeinkből. A terepi vizsgálataink során felmért 767 vízfolyásszakasz 78,7%-ról mutattuk ki idegenhonos fajok egyedeit. A felmérések során fogott fajok 28,8%-át, illetve a fogott összegyedszám 18,27%-át az idegenhonos halak adták. A kis-és közepes vízfolyásokban az ezüstkárász, a kínai razbora és a naphal voltak a leggyakoribb idegenhonos fajok. Itt az elterjedési mintázatokat és relatív abundancia viszonyokat elsősorban a tengerszint feletti magasság, valamit a halastavak jelenléte-hiánya, illetve azok relatív helyzete befolyásolta. Nagyobb vízfolyásokban a gébfélék a domináns idegenhonos fajok. Az országos adatokkal összevetve a balatoni vízgyűjtőn fokozottabban terhelt inváziós fajokkal. Ugyanakkor az idegenhonos fajok vízgyűjtőn tapasztalt elterjedés-intázata arra utal, hogy nem elsősorban a tavak megléte, hanem inkább azok üzemrendje lehet az a tényező, ami döntően befolyásolja a környezetükben lévő vízfolyásszakaszok idegenhonos fajokkal való fertőzöttségét. Véleményünk szerint a klímaváltozás miatt újabb spontán terjedő idegenhonos fajok megjelenésére mindenképpen számítanunk kell a közeljövőben. Ugyanakkor az emberi segítséggel terjedő fajok további térnyerése jelentősen lassítható lenne, az akvarisztikai célú halkereskedelem, a horgásztavi telepítések, illetve a vízgyűjtőket átszelő halastavak közti halszállítmányozás fokozottabb ellenőrzésével.
Background Invasive gibel carp, Carassius gibelio (Bloch, 1782) has become well-established in th... more Background Invasive gibel carp, Carassius gibelio (Bloch, 1782) has become well-established in the Hungarian waters and now are spreading in the European waters. On major concern now is the potential hybridization between gibel carp and the other invasive species in the Carassius auratus complex (CAC), which may further accelerate the spread of the whole invasive species complex. The identification of gibel carp and their hybrids is difficult because of its morphological similarity to the other species in CAC. Here we carry out a genomic assessment to understand the history of gibel carp invasion and its phylogenetic relationship with the other species in CAC. Three loci of the mitochondrial genome (D-loop, CoI, Cytb) were used to determine the phylogenetic origin of individuals and relarionship among six gibel carp populations and the other species in the CAC. Methodolgy A total of 132 gibel carp samples from six locations in Southern Transdanubia (Hungary) were collected after phe...
Recent researches suggest that functional diversity represents the response of communities to env... more Recent researches suggest that functional diversity represents the response of communities to environmental alterations better than taxonomic diversity. However, there is scarce information about how the functional diversity of freshwater fishes is affected by habitat type and the dominance of non-native species. To address this question, we analysed a large database containing 15 morpho-functional traits of 61 fish species from the Pannon Biogeographic region (Hungary). Based on a fish faunistic list and relative abundance of taxa, we quantified the taxonomic and functional diversity of riverine communities for > 700 sites of six habitat types. We asked how non-native fishes affected the taxonomic and functional diversity in different river types and at the local scale (i.e. at the site level), and how the diversity measures of native fauna elements changes along the invasion gradient. Our results showed that both functional and taxonomic richness increases with habitat complexi...
In this study, we provide the first genetically verified distribution record of Ligula pavlovskii... more In this study, we provide the first genetically verified distribution record of Ligula pavlovskii, a high-impact endoparasite of Ponto-Caspian gobies, beyond its native range. According to parasitological surveys, ligulosis was detected for the first time in monkey goby individuals collected from Lake Balaton in 2004, 34 years after the first record of monkey goby in the lake. During a Lake Balaton survey in 2018, we detected tapeworms in 44.4% of the sampled monkey gobies. This prevalence is about two to ten times higher than it was reported from within the native range of the fish hosts. The same survey revealed an uneven spatial distribution of the ligulosis in the monkey gobies inhabiting different shoreline sections of the lake. We assume that the occurrence and recent distribution data of this high-impact endoparasite may provide useful information for potential biocontrol measures of invasive Ponto-Caspian gobies in the future.
Knowledge of intraspecific variability of a certain species is essential for their long-term surv... more Knowledge of intraspecific variability of a certain species is essential for their long-term survival and for the development of conservation plans. Nowadays, molecular/genetic methods are the most frequently used for this purpose. Although, the Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) technique has become a promising alternative tool to specify intraspecific variability, there is a lack of information about the limitations of this method, and some methodological issues need to be resolved. Towards this goal, we tested the sensitivity of this method on an intraspecific level, using genetically identified individuals of a cryptic fish species complex collected from five distinct populations. Additionally, some methodologic issues, such as the effect of (1) delayed sample preparation, (2) clove oil anaesthetization, and (3) different tissue types (muscle, and brain) were investigated using the MS analysis results. Our results show tha...
Detailed knowledge on the habitat preference of invasive fishes and the bias of different fishing... more Detailed knowledge on the habitat preference of invasive fishes and the bias of different fishing methods in determining their population dynamic parameters are essential in fisheries management, ecology and conservation. This study was conducted to determine the habitat use and length frequency distribution of the invasive monkey goby and pumpkinseed in the littoral zone of Lake Balaton (Hungary) using two different sampling methods, electrofishing and fyke netting. In general, both species preferred anthropogenically modified habitat types (rip-rap shorelines and harbours) compared with natural reed habitats with silty-sand bottom. Length frequency distribution data showed significant between-gear differences, since electrofishing resulted in the capture of larger individuals in greater proportion than fyke nets for both species. This study, which includes the first detailed data about the habitat use of the highly invasive monkey goby in lakes, suggests that invasive species may benefit from the alteration of the littoral zone. It also highlights that reliance on single gear surveys can be misleading in assessing habitat use and population structure of invasive fishes.
Environmental Engineering and Management Journal, 2016
We examined the effluent from a municipal (Nyíregyháza, Hungary) wastewater treatment plant (WWTP... more We examined the effluent from a municipal (Nyíregyháza, Hungary) wastewater treatment plant (WWTP) on hydrophysicochemical properties and on diversity, community structure, and stability of fish assemblages at the recipient low flow channel system during a two-year period. The WWTP outflow increased significantly the nutrient concentrations (e.g. NO2 and NO3 concentrations increased to 4x and 8x respectively), and the regime (with the permanent ~0.23m 3 /s load) at the recipient channel sections. The wastewater outflow not only altered, but stabilized the physico-chemical variables measured, and the water regime in the recipient channels. Thus the natural, periodic fluctuation of the environmental variables was diminished in the study period. The WWTP outflow caused significant changes in the fish fauna as well. High abundances and taxa richness were found in the stocks inhabiting the charged watercourse sections. At the same time, species composition and relative abundances of fish stocks proved to be more constant at the impaired sites. Our results show that the WWTP outflow caused altered, but significantly more stable environmental conditions. These alterations were favourable for the emergence of a more diverse and more stable fish community on the recipient channel sections. Hence, the dynamic variability in fish assemblage structure that is characteristic of natural lowland stream was not apparent in these perturbed, semi natural habitats.
Quantifying the relative importance of how local (environmental or niche‐based) and regional (dis... more Quantifying the relative importance of how local (environmental or niche‐based) and regional (dispersal‐related or spatial) processes regulate the assembly of communities has become one of the main research avenues of community ecology. It has been shown that the degree of isolation of local habitats in the landscape may substantially influence the relative role of environmental filtering and dispersal‐related processes in metacommunities. Dendritic stream networks are unique habitats in the landscape, where more isolated upstream sites have been predicted to be primarily structured by environmental variables, while more central mainstem rivers by both environmental and spatial variables (hereafter the network position hypothesis, NPH). However, the NPH has almost exclusively been tested for stream macroinvertebrates, and therefore its predictions warrant confirmation from multiple taxa. We examined the validity of the NPH for benthic diatoms, macrophytes, macroinvertebrates and fis...
Due to its central position in the Danube basin and its considerable fishery sector, Hungary play... more Due to its central position in the Danube basin and its considerable fishery sector, Hungary plays a key role in the spread of non-native fish species in Europe. Nevertheless, the status of non-native fish has not yet been reviewed for Hungary. Therefore, our aims were 1) to give a comprehensive historical overview regarding the occurrence of non-native fish species of Hungary, 2) to show their recent distribution patterns using GIS, and 3) to evaluate the importance of the possible drivers in their spread. Literature data show 59 non-native fish species from Hungary. The appearance of new species-mostly due to aquarium fish releasesshows an accelerating trend nowadays. Although non-native fish have appeared at 78.7% of the studied 767 sites during our recent countrywide survey, their distribution was uneven. Lowland streams, lowland rivers, and the River Danube were the most affected by non-native fish, particularly the gibel carp, topmouth gudgeon and pumpkinseed escaped from fish/angling ponds, and the recent invasion of Ponto-Caspian gobies. Our results indicated that in order to reduce the effects and intensity of further invasions, more rigorous control of aquarium trade, angling pond stockings, and inter-watershed fish transports are necessary. keywords: invasion, invasive species, fisheries, aquarium trade, ecological risks, Carpathian basin Fish faunistic surveys were made within the frame of the following projects: OTKA CNK80140, OTKA K104279, OTKA PD115801, and a KEHOP2015 project of the General Directorate of Water Management. We would like to express our thanks to colleagues at the General Directorate of Water Management, but Gy. I. Tóth and T.A. Zagyva for their help in several phases of the work. Data analysis was supported by the GINOP 2.3.2-15-2016-00004 project. Árpád Ferincz was supported by the Bolyai Fellowship of the Hungarian Academy of Sciences.
Running head: fish metacommunities in stream networks types in riverscapes, and niche based speci... more Running head: fish metacommunities in stream networks types in riverscapes, and niche based species sorting mechanisms are more influential in their structuring than dispersal ones. Landscape classifications are useful for a better understanding of the structuring of metacommunities in both the freshwater and the terrestrial realm.
The genetic structure of European mudminnow populations throughout the species range was examined... more The genetic structure of European mudminnow populations throughout the species range was examined using mitochondrial DNA and seven microsatellite loci. Ten mitochondrial haplotypes were detected, suggesting three phylogeographic lineages, which likely diverged during the Early and Middle Pleistocene. These three lineages geographically correspond to three regions: the Danube drainage including the Drava system and Dniester Delta, the Sava system, and the Tisza system. High genetic diversity observed using mtDNA was confirmed with microsatellite data, suggesting the existence of 14 populations in the studied area. The isolation-with-migration model showed that migration rates between populations were generally low, and were highest between the Drava and its tributary Mura. According to the inferred relative population splitting times, U. krameri likely spread from the eastern part of the species range to the west, which also showed the highest genetic diversity and largest population size. As reported by the time-calibrated phylogeny, separation of the European and American Umbra occurred roughly at the end of Late Cretaceous and in the first half of the Paleogene (60.57 Ma with 95% highest probability density of 39.57-81.75). Taking these results into account, appropriate guidelines are proposed to conserve European mudminnow populations.
We compared the repeatability, reproducibility (intra-and inter-measurer similarity), separative ... more We compared the repeatability, reproducibility (intra-and inter-measurer similarity), separative power and subjectivity (measurer effect on results) of four morphometric methods frequently used in ichthyological research, the "traditional" caliper-based (TRA) and trussnetwork (TRU) distance methods and two geometric methods that compare landmark coordinates on the body (GMB) and scales (GMS). In each case, measurements were performed three times by three measurers on the same specimen of three common cyprinid species (roach Rutilus rutilus (Linnaeus, 1758), bleak Alburnus alburnus (Linnaeus, 1758) and Prussian carp Carassius gibelio (Bloch, 1782)) collected from three closely-situated sites in the Lake Balaton catchment (Hungary) in 2014. TRA measurements were made on conserved specimens using a digital caliper, while TRU, GMB and GMS measurements were undertaken on digital images of the bodies and scales. In most cases, intra-measurer repeatability was similar. While all four methods were able to differentiate the source populations, significant differences were observed in their repeatability, reproducibility and subjectivity. GMB displayed highest overall repeatability and reproducibility and was least burdened by measurer effect. While GMS showed similar repeatability to GMB when fish scales had a characteristic shape, it showed significantly lower reproducability (compared with its repeatability) for each species than the other methods. TRU showed similar repeatability as the GMS. TRA was the least applicable method as measurements were obtained from the fish itself, resulting in poor repeatability and reproducibility. Although all four methods showed some degree of subjectivity, TRA was the only method where population-level detachment was entirely overwritten by measurer effect. Based on these results, we recommend a) avoidance of aggregating different measurer's datasets when using TRA and GMS methods; and b) use of image-based methods for morphometric surveys. Automation of the morphometric workflow would also reduce any measurer effect and eliminate measurement and data-input errors.
Risk assessment of non-native fishes in the catchment of the largest Central-European shallow lak... more Risk assessment of non-native fishes in the catchment of the largest Central-European shallow lake (Lake Balaton, Hungary).
The European mudminnow (Umbra krameri) is a Middle Danubian endemic fish species, which is charac... more The European mudminnow (Umbra krameri) is a Middle Danubian endemic fish species, which is characterised by isolated populations living mainly in artificial habitats in the centre of its range, in the Carpathian Basin. For their long term preservation, reliable information is needed about the structure of stocks and the level of isolation. The recent distribution pattern, and the population genetic structure within and among regions were investigated to designate the Evolutionary Significant, Conservation and Management Units (ESUs, CUs, MUs) and to explore the conservation biological value of the shrinking populations. In total, eight microsatellite loci were studied in 404 specimens originating from eight regions. The results revealed a pronounced population structure, where strictly limited gene flow was detected among regions, as well as various strengths of connections within regions. Following the results of hierarchical structure analyses, two ESUs were supposed in the Carpat...
Present study established correlations between the spatial distribution of three stream-dwelling ... more Present study established correlations between the spatial distribution of three stream-dwelling fish species (chub, stone loach and gudgeon), the environmental variables which affect their distribution, and the genetic structure of their assemblages, in a North Hungarian drainage system. The spatial distribution of gudgeon and stone loach (which have more specific habitat needs) was affected by elevation, slope and distance from the mouth. Chub occurred frequently in the wider and deeper streams of the hills with higher velocity, but was repeatedly caught in lowland situated sections close to the mouth as well. Genetic data obtained with AFLP were correlated with distribution and as a result higher genetic distances were revealed among gudgeon and stone loach than among chub assemblages. The assemblages of the former two species show a clear pattern of isolation by distance. Results suggest that lowland sections of the studied streams might act as ecological barriers for stone loach and gudgeon assemblages, but not for the chub. Hence, in this drainage system the stone loach and gudgeon appear with separated populations while the chub is characterized by a metapopulation structure.
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