Current stocking program of the sterlet (Acipenser ruthenus, L.) can negatively shape its genetic variability in the Middle Danube

The Danube River was originally inhabited by six native sturgeon species, but currently, the sterlet (Acipenser ruthenus L.) is the only native sturgeon species still occupying the Slovak–Hungarian stretch of the Middle Danube. All sturgeon species are facing extinction, suffering from overfishing, water pollution, illegal fishing, poaching or other negative impacts. Urgent and proper actions are needed to prevent their extinction, and evaluating its genetic diversity is one of the essential tools of conservation programs. Since the management actions are primarily local in nature, we first focused on comparing and analysing local sources of fish for population recovery and natural (wild) population in the adjacent stretch of the Danube River. We used 2 fragments of mitochondrial DNA and 12 microsatellites to analyse the genotype of the three groups of sterlets, i.e. wild, broodstock and stocked individuals from Slovak part of the Danube. Mitochondrial markers of all groups were diversified similarly to populations from other parts of the Danube. This confirmed that broodstock and stocked fish belong to the original Danube population. Microsatellites revealed very similar patterns among groups compared, but we detected possible negative trends reflected in losing polymorphism in a few loci in broodstock and stocked individuals

MULTIDISCIPLINARY EVALUATION OF THE FUNCTION AND IMPORTANCE OF THE SMALL WATER RESERVOIRS: THE BIODIVERSITY ASPECT

ABSTRACT Small water reservoirs are the very important landscape elements for effective water management. Although these man-made artificial biotopes change the proportion of lotic and lentic habitats and thus influence the species community structure, them secondarily offer a broader scale of microhabitats and, in general, can significantly influence the fauna's sustainable development. The evaluation of the function and importance of small water reservoirs in the biodiversity development on all levels is still unappreciated. In this case, preliminary results of the study on six small water reservoirs in West Slovakia are presented. The research has covered the major species groups (phytobentos, macrophytes, benthic and pelagic invertebrates, mollusks, fish and birds). As the first step, we are focusing on the description of the biodiversity patterns within the particular water reservoirs followed by the analyses of species links to the environmental variables using the multidimensional methods (neural networks, ordination methods and generalized linear methods) as the second step. The third step covers the compilation of obtained results and evaluation of the function and importance of the small water reservoirs. The major benefits of this study are as follows: (i) significant improvement of the knowledge on the biodiversity of aquatic ecosystems influenced by small water reservoirs, (ii) implementation of the innovative methods of the multidisciplinary ecological research, (iii) support for sustainable development of the biodiversity in artificial biotopes, development of the multidisciplinary network of researchers and experts from the applied sphere, (iv) effective application of outputs in the ecological management oriented to the sustainable development of the artificial aquatic ecosystems in combination with their primary use and implementation of the results gained at the international scale. L. Pekárik et al. -Multidisciplinary evaluation of small water reservoirs: the biodiversity aspect (105 ~ 112) 106 RÉSUMÉ: Evaluation multidisciplinaire de la fonction et de l'importance des étangs. L'aspect de la biodiversité. Les petits corps d'eau sont des éléments de paysage très importants pour la gestion efficace de l'eau. Même si ces biotopes artificiels changent les proportions des habitats lotiques et lentiques, elles offrent également une échelle plus large de microhabitats et, généralement, elles peuvent influencer de manière signifiante le développement durable de la faune. L'évaluation de la fonction et de l'importance des étangs dans le développement de la biodiversité à tous niveaux est encore sous appréciée. Dans ce cas, nous présentons les résultats préliminaires d'une étude effectuée sur 6 étangs anthropiques de l'Ouest de la Slovakie. La recherche a compris les groupes spécifiques majeurs (phytobentos, macrophytes, invertébrés benthiques et pélagiques, mollusques, poissons et oiseaux). En première étape, nous nous sommes concentrés sur la description des modèles de biodiversité de ces étangs suivie, en deuxième étape, par l'analyse des relations entre les espèces et les variables de l'environnement en utilisant des méthodes multidimensionnelles (des réseaux neuronaux, des méthodes d'ordination et des méthodes linéaires généralisées); la troisième étape comprend la compilation des résultats obtenus et l'évaluation de la fonction et de l'importance des étangs. Les bénéfices majeures de cette étude sont les suivantes: (i) amélioration significative de la connaissance de la biodiversité des écosystèmes aquatiques sous l'influence des étangs, (ii) l'implémentation des méthodes nouvelles dans la recherche écologique multidisciplinaire, (iii) un support pour le développement durable de la biodiversité dans les biotopes artificiels, le développement des réseaux multidisciplinaires des chercheurs et d'experts de la sphère appliquée, (iv) l'application effective des résultats dans la gestion écologique orientée vers le développement durable des écosystèmes aquatiques artificielles combinée à leur utilisation primaire et l'implémentation à l'échelle internationale des résultats obtenus. REZUMAT: Evaluare multidisciplinară a funcţiei şi importanţei iazurilor: aspectul biodiversităţii. Iazurile şi heleşteele sunt elemente peisagistice foarte importante pentru gestiunea eficientă a apei. Deşi aceste biotopuri artificiale modifică proporţiile habitatelor lotice şi lentice şi influenţează astfel structura comunităţilor biologice, ele oferă secundar o gamă mai largă de microhabitate, în general, pot influenţa de manieră semnificativă dezvoltarea durabilă a faunei. Evaluarea funcţiei şi importanţei iazurilor în dezvoltarea biodiversităţii la toate nivelurile este încă neglijată. În acest caz, sunt prezentate rezultatele preliminare ale unui studiu pe şase iazuri mici, din vestul Slovaciei. Cercetările au acoperit grupele majore de specii (fitobentos, macrofite, nevertebrate bentice şi pelagice, moluşte, peşti şi păsări). Într-o primă etapă, ne-am concentrat pe descrierea modelelor de biodiversitate, aplicate la iazurile studiate, apoi am efectuat analiza relaţiilor interspecifice cu ajutorul metodelor multidimensionale (reţele neuronale, metode de ordonare şi metode liniare generalizate) care au constituit a doua etapă a studiului. A treia etapă a acoperit compilarea datelor obţinute şi evaluarea funcţiei şi importanţei iazurilor. Beneficiile principale ale studiului sunt următoarele: (i) ameliorarea semnificativă a cunoaşterii biodiversităţii ecosistemelor acvatice sub influenţa iazurilor, (ii) implementarea de metode noi, inovatoare în cercetarea ecologică multidisciplinară, (iii) suport pentru dezvoltarea durabilă a biodiversităţii în biotopurile artificiale, dezvoltarea de reţele multidisciplinare de cercetători şi experţi din sfera aplicată, (iv) aplicarea efectivă a rezultatelor gestiunii ecologice, orientate spre dezvoltare durabilă a ecosistemelor acvatice artificiale, în paralel cu utilizarea lor primară şi implementarea rezultatelor obţinute la scară internaţională. Transylv. Rev. Syst. Ecol. Res. 8, (2009), "The Wetlands Diversity" 107 INTRODUCTION Small water reservoirs The artificial small water reservoirs were built on small streams in the first place for the purpose of their potential for irrigation and as flood protection. But also their contribution to the nature protection through the water self-purification is not negligible Small water reservoirs are very important landscape elements for effective water management. Although these man-made artificial ponds change the proportion of lotic and lenitic habitats and thus influence the species community structure, secondarily offer a broader scale of microhabitats and, in general, can significantly influence the fauna sustainable development. The evaluation of the function and also of the importance of the small water reservoirs on the biodiversity development on all levels is still unappreciated. Ertl The aim of the project SAV-FM-EHP-2008-03-04 is to identify the function of small water reservoirs in the system of aquatic biotopes of the Slovakia in respect to preservation and development of water biota diversity. The results should enable to model the development of the biodiversity for the purpose of reservoir management with the respect of ecological value of the reservoirs. Management should involve the primary purposes of reservoirs together with effective protection of the nature. This paper brings first results of limnology of selected six reservoirs of the west Slovakia

Distribution patterns and habitat requirements of the species of the family Cobitidae in Slovakia

Distribution patterns and major environmental correlations of the species of the family Cobitidae are presented here. All three species are still relativem widely distributed in Slovakia. Comparing with the past, no rapid ganges have been found. However, river regulation, pollution and the lowland amelioration affected the distribution of these species. Following the results of the occurrence of Balkan spined loach (Sabanejewia balcanica) within the mesohabitat scale, distance from source, slope, water depth and vegetation cover are the most influential variables in the proposed model. All these variables that contribute to our model explanation determine the stream morphology that affects the consequences of local temperature conditions and other abiotic factors as oxygen amount. Switching to microhabitat spatial scale, several microhabitat variables significantly influence the spatial distribution of analysed species. Depth more than 40 cm, refuges stones and point near bank (<15% of river width) are the most influential ones supplemented with substratum sand, substratum cobbles, substratum boulders, no refuges, refuges woody, depth 0-10 cm and maximum velocity none. Balkan spined loach occurs in the microhabitats occupied also by young-of-the-year (YOY) individuals and common minnow (Phoxinus..

The sterlet (Acipenser ruthenus) in the middle Danube: What are the causes of the average weight increase?

The sterlet is the last regularly documented native sturgeon species in the Slovak-Hungarian stretch of the middle Danube. The current status of the species is generally unknown because there is lack of the data. There is no commercial fishing there and the only reliable data are the catches recorded by Slovak Anglers Club Union. We have used the data on the catches and the weights of all sampled sterlets between the yeas 2003 and 2014. Catches are continuously decreasing and the average height is increasing. Two hypotheses are available, the changes in angling practises to catch larger fishes or the increasing age of the population. The angling practises changed in last two decades with using larger hooks with favourite baits so there is higher probability to sample larger specimens. On the other hand, the number of sampled individuals are decreasing as well. Further research is needed to uncover the population characteristics of the sterlet in the middle Danube as well as to increase of the knowledge of spawning, feeding and wintering habitats

Rozšíření a habitatové nároky druhů čeledi Cobitidae na Slovensku

RozSfienfa habitatov6niroky druhrfiieledi Cobitidaena Slovensku Mgr.LadislavPek6rik (souhmk dizertadnipr6ciDistributionpattemsandhabitatrequirementsof the speciesof thefamily Cobitidaein Slovakiav deskdmjazyce) V5echnytii druhydelediCobitidaejsouv soudasnostinaSlovenskurelativnESiroceroz5iien6(s vjjimkou Baltskdhorimoii).Cobitiselongatoidesje nejroz5iienEj5ianejpodefirdjBijak v distdform6tak i v hybridnichdiploidnE-polploidnichkomplexech.$s$rtuje sev iekdchi v primrirnfcha sekund6rnichakvatic[fch habitatechniLin.Z primrirnichbiotopripreferujeiidni koryto atEZiStE rnjslqrtuv sekundr{rnichtypechbiotoptije v melioradnichkan6lechat1ilebnichjam6ch.Pii porovnrinfs roky 1955-1965nedoSlokvlraznf zmEnEv roz5iienitohotodruhu.Typick6druhovdspoledenstvopro tentoreofilni druhtvoii eurytopnfalimnofilni druhy.Sabanejewiabalcanicasevyskytujevdt5inouv sdednichrisecichvodnichtokt, v prvniiaddv povodiBodrogu(iekyLaborec,OndavaaTopl'a)na v'-ichodnimSlovensku.Y zhpadniddstiSlovenska(povodiDunaje)setentodruhvyskytujev men5i miie aspi5eosfi:rivkovitd.Av5akv poslednichletechbyli objevenydaltsipopulacev zhpadnid6sti SlovenskaapravdEpodobndje jeji roz5iieniv t5rtooblastipodhodnoceno.Distribucedruhuje omezena jenomnaprimrirnibiotopy,ato ieky stwdBimsubstr6tem.Tentodruhbyl dlovdkemv minulosti nejviceovlivnEnato...Distribution patterns and major environmental correlations of the species of the family Cobitidae are presented here. All three species are still relativem widely distributed in Slovakia. Comparing with the past, no rapid ganges have been found. However, river regulation, pollution and the lowland amelioration affected the distribution of these species. Following the results of the occurrence of Balkan spined loach (Sabanejewia balcanica) within the mesohabitat scale, distance from source, slope, water depth and vegetation cover are the most influential variables in the proposed model. All these variables that contribute to our model explanation determine the stream morphology that affects the consequences of local temperature conditions and other abiotic factors as oxygen amount. Switching to microhabitat spatial scale, several microhabitat variables significantly influence the spatial distribution of analysed species. Depth more than 40 cm, refuges stones and point near bank (&lt;15% of river width) are the most influential ones supplemented with substratum sand, substratum cobbles, substratum boulders, no refuges, refuges woody, depth 0-10 cm and maximum velocity none. Balkan spined loach occurs in the microhabitats occupied also by young-of-the-year (YOY) individuals and common minnow (Phoxinus...Katedra zoologieDepartment of ZoologyPřírodovědecká fakultaFaculty of Scienc

Current stocking program of the sterlet (

The Danube River was originally inhabited by six native sturgeon species, but currently, the sterlet (Acipenser ruthenus L.) is the only native sturgeon species still occupying the Slovak–Hungarian stretch of the Middle Danube. All sturgeon species are facing extinction, suffering from overfishing, water pollution, illegal fishing, poaching or other negative impacts. Urgent and proper actions are needed to prevent their extinction, and evaluating its genetic diversity is one of the essential tools of conservation programs. Since the management actions are primarily local in nature, we first focused on comparing and analysing local sources of fish for population recovery and natural (wild) population in the adjacent stretch of the Danube River. We used 2 fragments of mitochondrial DNA and 12 microsatellites to analyse the genotype of the three groups of sterlets, i.e. wild, broodstock and stocked individuals from Slovak part of the Danube. Mitochondrial markers of all groups were diversified similarly to populations from other parts of the Danube. This confirmed that broodstock and stocked fish belong to the original Danube population. Microsatellites revealed very similar patterns among groups compared, but we detected possible negative trends reflected in losing polymorphism in a few loci in broodstock and stocked individuals

Asexual Reproduction Does Not Apparently Increase the Rate of Chromosomal Evolution: Karyotype Stability in Diploid and Triploid Clonal Hybrid Fish (Cobitis, Cypriniformes, Teleostei)

<div><p>Interspecific hybridization, polyploidization and transitions from sexuality to asexuality considerably affect organismal genomes. Especially the last mentioned process has been assumed to play a significant role in the initiation of chromosomal rearrangements, causing increased rates of karyotype evolution. We used cytogenetic analysis and molecular dating of cladogenetic events to compare the rate of changes of chromosome morphology and karyotype in asexually and sexually reproducing counterparts in European spined loach fish (<i>Cobitis</i>). We studied metaphases of three sexually reproducing species and their diploid and polyploid hybrid clones of different age of origin. The material includes artificial F1 hybrid strains, representatives of lineage originated in Holocene epoch, and also individuals of an oldest known age to date (roughly 0.37 MYA). Thereafter we applied GISH technique as a marker to differentiate parental chromosomal sets in hybrids. Although the sexual species accumulated remarkable chromosomal rearrangements after their speciation, we observed no differences in chromosome numbers and/or morphology among karyotypes of asexual hybrids. These hybrids possess chromosome sets originating from respective parental species with no cytogenetically detectable recombinations, suggesting their integrity even in a long term. The switch to asexual reproduction thus did not provoke any significant acceleration of the rate of chromosomal evolution in <i>Cobitis</i>. Asexual animals described in other case studies reproduce ameiotically, while <i>Cobitis</i> hybrids described here produce eggs likely through modified meiosis. Therefore, our findings indicate that the effect of asexuality on the rate of chromosomal change may be context-dependent rather than universal and related to particular type of asexual reproduction.</p></div

Representative karyotypes of hybrid biotypes after GISH and/or DAPI/Giemsa staining.

<p>(A) EN hybrid metaphase with hybridization pattern of <i>Cobitis elongatoides</i> gDNA in green, <i>C</i>. <i>tanaitica</i> gDNA in red. (B) ET hybrid with <i>C</i>. <i>elongatoides</i> in red, <i>C</i>. <i>taenia</i> in green. (C) EEN hybrid with <i>C</i>. <i>elongatoides</i> in green, <i>C</i>. <i>tanaitica</i> in red. (D) EET hybrid with <i>C</i>. <i>elongatoides</i> in red, <i>C</i>. <i>taenia</i> in green. (E) ENN hybrid with <i>C</i>. <i>elongatoides</i> in red, <i>C</i>. <i>tanaitica</i> in green. (F) ETT hybrid with <i>C</i>. <i>elongatoides</i> in red, <i>C</i>. <i>taenia</i> in green. Capital letters represent haploid genome sets: E, <i>C</i>. <i>elongatoides</i>; N, <i>C</i>. <i>tanaitica</i>; T, <i>C</i>. <i>taenia</i>. Chromosomes were arranged in a decreasing size order and classified in four morphological groups: metacentric (m), submetacentric (sm), subtelocentric (st) and acrocentric (a). Probes labelled with biotin-16-dUTP were detected with FITC-streptavidin (green signals on chromosomes); probes labelled with digoxigenin-11-dUTP were detected with anti-digoxigenin-rhodamin (red signals on chromosomes). To visualize the morphology of chromosomes DAPI (A, B, C, D) or Giemsa (E, F) stained karyotype was used. Captured DAPI stained karyotypes were inverted. Bars equal 5 μm. Detail information about individuals used is provided in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0146872#pone.0146872.s004" target="_blank">S1 Table</a>.</p

Ultrametric phylogenetic tree demonstrating estimated speciation times of parental species and the Hybrid clade I.

<p>Species-specific karyotypes arranged from Giemsa stained chromosomes are shown along the right side of cladogram. Confidence intervals of nodes of interest are in grey colour. TT, <i>C</i>. <i>taenia</i>; NN, <i>C</i>. <i>tanaitica</i>; EE, <i>Cobitis elongatoides</i>. Chromosomes were arranged in a decreasing size order and classified in four morphological groups: metacentric (m), submetacentric (sm), subtelocentric (st) and acrocentric (a).</p