Session B5: The Danube Fish Bypass System of Vienna/Freudenau and its Importance as a Lifecycle Habitat

Abstract: For the fish bypass at the Danubehydropower station Wien/Freudenau the functioning as migration facility has been classified as functional after construction in 1997. The importance of habitat support for the lifecycles of Danube fish species becomes clearly visible in times when degraded, impounded, current speed reduced section of the river are dominating the fluvial ecosystem. Central parts of impounded areas are not supporting all the needs of riverine fish: Gravel-spawning grounds, suitable flow velocity and diverse 0+ fish habitats are missing. Upper most part of impoundments, tributaries and artificial rivers, like fish bypass systems, can function as essentially needed last habitats. The fish bypass system of Wien/Freudenau has a length of 1.6 km and a discharge of at least 1.5 m³. 2/3 of the system has been constructed as a near-natural circumvention stream and 1/3 as a nature-like pool pass. After 15 years of operation it becomes clearly visible that fish use the bypass system as spawning ground extensively and therefore it can make an important contribution for the maintenance of several endangered species, like the nase (Chondrostoma nasus) and the barbel (Barbus barbus). In the present study a monitoring was conducted throughout a year. Seasonal changes in abundances, species diversity and spawning events were observed. A total of 35 species colonize the bypass with temporary and spatial fluctuations. In early spring (February and March), the indicator species of the free flowing Danube, nase and barbel, migrated into the fish pass in very high quantities. After spawning in April and May the adults disappeared and a few weeks later thousands of young-of-theyear were observed. The present data show, that the chosen natural like solution of a bypass system serves in contrast to a hard technical construction, - additionally to its migration function - like a Danube tributary of the grayling zone. 23 species of young-of-theyear fish classes’ inhabited the system in 2014. Some of them have been proved in larval stages by barcoding

Ökonomische, ökologische und Tierwohlaspekte der Weidehaltung von Hochleistungskühen

Dieses Projekt zielte darauf ab, die Grünlandnutzung durch Weidehaltung für Milchkühe mit zu untersuchen. Vor dem Hintergrund, dass der Energiebedarf durch alleinige Weidehaltung in den Sommermonaten nicht gedeckt werden kann und Weidehaltung mit einem höheren Arbeits-aufwand verbunden sein kann, jedoch gleichwohl positive Effekte auf die Tiergesundheit dokumentiert wurden, war es das Ziel zu untersuchen, ob ein ökonomisch messbarer Weideeffekt besteht und welche Rolle das Tierwohl sowie die ökologischen Landschaftsfunktionen des Grünlandes spielen. Die Ergebnisse der on-farm Analyse zeigten, dass bei kombinierter Stall- und Weidehaltung ähnlich hohe Milchleistungen wie bei ganzjähriger Stallhaltung möglich sind. Auffälligkeiten am Integument der Tiere resultieren hauptsächlich aus Mängeln in der Haltungsumwelt und können das Tierwohl erheblich beeinträchtigen. Die Haltung auf der Weide bringt unter diesem Aspekt deutliche Vorteile, allerdings werden die Regenerationseffekte im folgenden Winter größtenteils wieder neutralisiert. Die Berücksichtigung dieser Aspekte in der Effizienzmessung zeigte, dass das mitunter größte Einsparpotential im Sinne einer Verbesserung der technischen Effizienz bei den Lahmheiten liegt. Es lässt sich kein Arbeitsmehraufwand bei den Weidebe-trieben im Saisonwechsel feststellen, da durch Einsparungen bei anderen Arbeitsvorgängen der Mehraufwand der Weidearbeiten ausgeglichen wurde. Das größte Potenzial bietet die Futterversorgung über die Weide. Hierfür ist ein eng aufeinander abgestimmtes Weide- und Herdemanagement essentiell, da unangepasstes Weidemanagement zu unterschiedlich ausgeprägten Trittschäden und in der Konsequenz zu Ertragsausfällen und Veränderungen der Futterqualität infolge von Verschieben der Artenzusammensetzung führt. Die Ergebnisse zeigten weiterhin, dass Grünlandnutzung als Weide zu einer erhöhten Humusspeicherung und somit zu einer echten klimawirksamen Kohlenstoffsequestrierung führt

Novel Human Parvovirus 4 Genotype 3 in Infants, Ghana

Human parvovirus 4 has been considered to be transmitted only parenterally. However, after novel genotype 3 of parvovirus 4 was found in 2 patients with no parenteral risks, we tested infants in Ghana. A viremia rate of 8.6% over 2 years indicates that this infection is common in children in Africa

Assessment of the ecological functionality of anthropogenically created habitats in the impoundment of the hydropower plant Freudenau (Vienna, Austria) with bi- and multivariate statistical analyses

The construction of the hydropower plant Freudenau was accompanied by the introduction of new structures and habitats. This study processes and evaluates the ecological fish data for the periods 1999/2000 and 2003/2004. The area was subdivided into five sections and 19 habitats (stream kilometer 1914.50 to 1994.60). Bi- and multivariate analyses were inducted with SPSS© (SPSS 2007). The CPUE values show that most fish remain in the Transition Zone and in the Head of Reservoir. The cluster analyses of the individual habitats show that these can be characterized primarily by abiotic factors. There was a strong statistical relationship between the individual habitats and the Danube mainstream. We conclude that fish have access to the habitats and that there is interconnectivity between these habitats. In general, the habitats were highly accepted by the fish species: all contained both juvenile and adult fish. The differentiated spectrum of species points to complex relationships. In principle the newly created habitats can be considered to be good replacement environments

Fish ecological assessment of an Austrian impoundment (HEPP Freudenau, Vienna) with cluster and discriminant analysis implicating dominances after Tischler (1949)

According to the demands of the European Union Water Framework Directive, natural structures and habitats were implemented during the construction of the hydropower plant Freudenau. Ecological data were processed and evaluated from the years 1999 to 2000 as well as from the years 2003 till 2004. The study area was divided into five parts, which were further divided into 19 habitats. The statistical software SPSS (© SPSS Inc. 2007) was used for statistical analysis. The dominances after Tischler were calculated and consulted for further analysis. In the context of this project an increase in the number of fish species from 1993 to 2004, showing a peak before and after the power station construction, was demonstrated. The CPUE values proved high magnitudes in the habitats B, D and I. The lowest number of individuals shows the Free Flowing Stretches. Both juvenile and adult fish could be proved in many habitats. A more exact analysis with the dominances after Tischler confirmed previous results. Nevertheless the change in the current spectrum of fish species points out interventions to the habitats. Anthropogenically created habitats are only substitutes for natural habitats

Growth and Nutrient Removal Efficiency of Sweet Wormwood (<i>Artemisia annua</i>) in a Recirculating Aquaculture System for Nile Tilapia (<i>Oreochromis niloticus</i>)

The maintenance of optimal water quality for fish production is one of the major challenges in aquaculture. Aquaponic systems can improve the quality of water for fish by removing the undesirable wastes and in turn produce a second marketable crop. However, there is no information on the growth and nutrient removal capability of Artemisia annua in aquaponic systems. This study evaluated the effect of plant density on water quality, the growth of A. annua and Oreochromis niloticus in a small scale aquaponic system in Kenya. The aquaponic system consisted of three treatments representing different plant densities (D1: 48 plants/m2, D2: 24 plants/m2 and D3:0 plants/m2). The high plant density system contributed significantly (p &lt; 0.05) to the removal of all nutrients. The removal efficiency of ammonia was significantly higher in D1 (64.1 &#177; 14.7%) than in D2 (44.5 &#177; 6.8%) and D3 (38.0 &#177; 12.1%). Nitrates and nitrites were inconsistent, whereas phosphorus increased gradually in all treatments. The productivity of plants was higher in D1 than D2. Fish growth rates were significantly higher in D1 (0.35 &#177; 0.03 g/d) and D2 (0.32 &#177; 0.02 g/d) than in D3 (0.22 &#177; 0.04 g/d). The results show that A. annua can be cultivated in aquaponic systems due to its nitrogen removal capabilities

The Role of Citrate Homeostasis in Merkel Cell Carcinoma Pathogenesis

Merkel cell carcinoma (MCC) is a rare but highly aggressive tumor of the skin with a poor prognosis. The factors driving this cancer must be better understood in order to discover novel targets for more effective therapies. In the search for targets, we followed our interest in citrate as a central and critical metabolite linked to fatty acid synthesis in cancer development. A key to citrate uptake in cancer cells is the high expression of the plasma membrane citrate transporter (pmCiC), which is upregulated in the different adenocarcinoma types tested so far. In this study, we show that the pmCiC is also highly expressed in Merkel cell carcinoma cell lines by western blot and human tissues by immunohistochemistry staining. In the presence of extracellular citrate, MCC cells show an increased proliferation rate in vitro; a specific pmCiC inhibitor (Na+-gluconate) blocks this citrate-induced proliferation. Furthermore, the 3D in vivo Chick Chorioallantoic Membrane (CAM) model showed that the application of Na+-gluconate also decreases Merkel cell carcinoma growth. Based on our results, we conclude that pmCiC and extracellular citrate uptake should be considered further as a potential novel target for the treatment of Merkel cell carcinoma

Effects of aerated and non-aerated biofilters on effluent water treatment from a small-scale recirculating aquaculture system for Nile tilapia (Oreochromis niloticus L.)

Most recirculation aquaculture systems (RAS) use aerated biofilters to maintain suitable water quality for fish production. However, application of non-aerated biofilters may provide opportunities to lower aeration costs, water usage and concentration of all nitrogenous wastes in the effluent water. Our study aimed at comparing the biofiltration performance characteristics of two biofilters: a conventional aerated biofilter and a non-aerated biofilter receiving the same effluent water from a small-scale RAS. The two biofilters were evaluated in triplicate and tested concurrently for seven months. Water quality parameters were monitored at the biofilter inlets and outlets and in the fish tanks. At the beginning of the experiment, the concentration of ammonia at the two biofilter outlets were not significantly different. However, the concentrations decreased with time reaching mean values of 1.33 ± 0.02 mg L−1 and 1.23 ± 0.21 mg L−1 N-NH4 in the aerated and non-aerated biofilters, respectively. Whereas phosphorus and nitrate levels were significantly high in the aerated biofilter. There was no significant difference in the growth of fish between the aerated and non-aerated biofilters. The results suggest that non-aerated biofilters can be as effective as aerated biofilters in maintaining suitable water quality for O. niloticus production