Attila Mozsár
University of Debrecen
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Featured researches published by Attila Mozsár.
Molecular Phylogenetics and Evolution | 2016
László Antal; Brigitta László; Péter Kotlík; Attila Mozsár; István Czeglédi; Miklós Oldal; Gábor Kemenesi; Ferenc Jakab; Sándor Alex Nagy
Three species of small-sized rheophilic Barbus fishes are endemic to and widely distributed throughout the mountain regions in the Danube River basin. In Hungary, barbels referred to as B. petenyi occur in streams in the foothills of the Carpathians near the borders with Slovakia, Ukraine and Romania. However, up to now, no genetic investigations were carried out on rheophilic barbels in this region. This study aims to clarify the taxonomic identity and distribution of the rheophilic barbels in the Hungarian plain based on molecular and morphological analyses. Two mitochondrial genes (cytochrome b, ATPase 6/8) and one nuclear gene (beta-actin intron 2) were sequenced and several morphometric and meristic characters were recorded. Phylogenetic and morphological analyses revealed that there are four genetically distinct lineages among the rheophilic barbels in the Carpathian Basin. The results demonstrated that North-Hungarian Barbus populations belong to B. carpathicus and that B. petenyi presumably does not occur in Hungary. As expected, B. balcanicus was only recorded in samples from the Balkans analyzed for reference. A distinct species, new to science, was discovered to be present in Sebes-Körös River (Crişul Repede) in eastern Hungary and western Romania and is formally described here as B. biharicus Antal, László, Kotlík - sp. nov.
Hydrobiologia | 2016
Judit Görgényi; Gergely Boros; Zoltán Vitál; Attila Mozsár; Gábor Várbíró; Gábor Vasas; Gábor Borics
The gut contents of filter-feeding fish often contain considerable amounts of viable phytoplankton cells; thus, these animals can act as vectors in the horizontal and vertical transport of algae. In this study, the potential role of the introduced filter-feeding Asian carps (hybrids of silver carp Hypophthalmichthys molitrix and bighead carp H. nobilis) in algal dispersion was studied in the oligo-mesotrophic Lake Balaton (Hungary). We examined the algal composition in the lake water, gut contents (foregut and hindgut), and occasionally in the filtered suspensions collected directly from the gill rakers (filtering apparatus) of fish. Microscopic analyses revealed that the phytoplankton composition of the ingested food differed considerably from what we found in the lake water. Cryptophytes, dinoflagellates, and euglenophytes were observed in both the lake water and foregut samples but were absent in the hindgut samples. However, in the cultured hindgut samples, we found viable cells of several phytoplankton taxa (e.g., diatoms, blue-greens, desmids, volvocalean and chlorococcalean green algae), which managed to survive the physical and chemical digestion. These results imply that the presence of these filter-feeding fish can alter the phytoplankton species composition and promote the dominance of taxa that are able to resist digestion.
Hydrobiologia | 2017
Diána Árva; Mónika Tóth; Attila Mozsár; András Specziár
Environmental heterogeneity plays a determinant role in structuring taxonomic and functional composition of local assemblages via various interacting processes as synthesized in the metacommunity theory. In this study, we evaluate the relative roles of local environmental and landscape filters, spatial constraints and seasonality in organization of assemblages of Chironomidae (Diptera), a diverse aquatic insect group with winged adults, in an extremely heterogeneous wetland system, Kis-Balaton, Hungary. As expected, local environmental variables explained a substantial proportion of assemblage variance mainly along sediment structure, macrophyte coverage, and decomposing plant matter gradients. Considering the narrow spatial range of the study area, pure spatial influence was unexpectedly strong, likely because of the dispersal limitation related to tall terrestrial vegetation patches and mass effect related to the uneven distribution and area of certain microhabitats and their species pools. However, landscape- and season-related variability proved to be low or negligible. Taxonomic and functional feeding guild (FFG)-based approaches revealed the same main trends in assemblage data; however, FFGs seemed to track environmental changes more tightly. We argue for the common use of taxonomic and functional-based approaches and advise the improvement of species optima and tolerance spectra databases to expand bioassessment power.
Inland Waters | 2017
Zoltán Vitál; Vilmos Józsa; András Specziár; Attila Mozsár; István Lehoczky; Balázs Kovács; Piotr Hliwa; Gergely Boros
Abstract The worldwide spread of bigheaded carp (Hypophthalmichthys spp.) is considered an ecological threat and problem in many countries. The aim of this study was to consider the likelihood of bigheaded carp reproduction in Lake Balaton and its catchment area (Hungary). The within-year trends of gonadosomatic index values show that female bigheaded carp increase ovary masses from spring until midsummer, after which a decline is typical. This trend may indicate bulk egg release, but the lack of a sharp drop in fecundity (number of eggs in the ovary) values during and after the potential spawning period suggests that a general and considerable ovary evacuation does not likely explain the declining gonadosomatic index values. Rather, it is more probable that female bigheaded carp resorb their eggs, supported by the presence of atretic oocytes in the ovaries after the potential spawning season. In turn, postovulatory follicles were present in the posterior ovary segments of 2 individuals, indicating that mature eggs were released by some females. The evidence of sporadic egg release does not necessarily imply that successful reproduction has occurred, however. The genetic analyses showed remarkable deviation from Hardy-Weinberg equilibrium within the stock, suggesting that bigheaded carp do not constitute a natural reproductive community in Lake Balaton. Thus, the present bigheaded carp stock in Lake Balaton likely derives primarily from external origin (i.e., from the surrounding fish ponds).
Hydrobiologia | 2017
Attila Mozsár; András Specziár; Izabella Battonyai; Gábor Borics; Judit Görgényi; Hajnalka Horváth; Mátyás Présing; László G.-Tóth; Zoltán Vitál; Gergely Boros
Abstract Planktivorous silver carp and bighead carp (collectively, the bigheaded carps) have been stocked worldwide and their invasion has caused severe impacts on many freshwater ecosystems. Exploiting the chance provided by the specific hybrid bigheaded carp stock in Lake Balaton (Hungary) covering the entire morphological range between the two species (including gill raker morphology), we implemented a comprehensive study (1) to reveal the feeding habits of hybrid bigheaded carps living in a mesotrophic, lacustrine habitat and (2) to assess how biotic and abiotic environmental factors and gill raker morphology affect diet composition. We found that all bigheaded carps utilized primarily zooplankton and neglected the scarce and inefficiently digestible phytoplankton, irrespective of gill raker morphology. Moreover, we observed strikingly high levels of inorganic debris consumption, but the proportion of inorganic matter in the guts was not associated directly with the concentration of suspended inorganic particles. Variance in the diet composition of bigheaded carps was related mostly to environmental factors, including the wind-induced resuspension of inorganic particles and seasonally variable availability of food resources. In conclusion, the effects of abiotic environmental factors and available food resources could overwhelm the effect of gill raker morphology in shaping the feeding habits of bigheaded carps.
Journal of Applied Ichthyology | 2014
Gergely Boros; Attila Mozsár; Z. Vitál; A. S. Nagy; András Specziár
Journal of Applied Ichthyology | 2015
Attila Mozsár; Gergely Boros; Péter Sály; László Antal; Sándor Alex Nagy
Aquatic Ecology | 2012
Gergely Boros; Jussi Jyväsjärvi; Péter Takács; Attila Mozsár; István Tátrai; Martin Søndergaard; Roger I. Jones
Archive | 2015
Zoltán Vitál; András Specziár; Attila Mozsár; Péter Takács; Gábor Borics; Judit Görgényi; László G.-Tóth; Sándor Alex Nagy; Gergely Boros
International Review of Hydrobiology | 2015
Sára Kati; Attila Mozsár; Diána Árva; Nastasia Julianna Cozma; István Czeglédi; László Antal; Sándor Alex Nagy; Tibor Erős