Session E2: Benefits of New Management of the Haringvliet Sluices and the Effects on Fish Migration

Abstract: The Rhine West Water Council is responsible for the regional implementation of the Water Framework Directive (WFD) and contributes to the River Basin Management Plan of the Rhine. The Rhine-West river basin is situated in the most western part of the Netherlands. It is highly industrialized and urbanized. Yet it is of major ecological importance with several ecologically important areas and main open connections from the sea to the rivers of the Dutch Delta. Thus, the Rhine-West region is a gateway to Europe, both economically and ecologically. In this duo-presentation, we would like to focus on: The Rhine-West Roadmap for Fish Migration, which complements the (inter)national Masterplan for fish migration (ICPR) which focuses on national waters. The roadmap highlights the importance of connecting the highways (national waters) to the regional roads (waters) in regards to fish migration. Its planning method makes good use of regional fish expert knowledge. The Roadmap easily identifies obstacles to fish migration and enables the selection and prioritizing of successful measures. The method is relevant to the restoration of all migratory fish, particularly in regard to the EU Eel Directive. The re-opening of the Haringvliet sluices (the Kier), one of the main hotspots for fish migration in The Netherlands. The presentation will highlights how ‘the Kier’ will give a strong impulse to the recovery of estuarine fish such as salmon, eel and sea trout in the Rhine and Meuse river basins. The presentation will also focus on the difficult decision making process which was necessary to re-open the estuary partly, with respect to all water users in the delta (including agriculture, fisheries, industry and drinking water)

Quantifying measures to limit wind driven resuspension of sediments for improvement of the ecological quality in some shallow Dutch lakes

Although phosphorus loadings are considered the main pressure for most shallow lakes, wind-driven resuspension can cause additional problems for these aquatic ecosystems. We quantified the potential effectiveness of measures to reduce the contribution of resuspended sediments, resulting from wind action, to the overall light attenuation for three comparable shallow peat lakes with poor ecological status in the Netherlands: Loosdrecht, Nieuwkoop, and Reeuwijk (1.8–2.7 m depth, 1.6–2.5 km fetch). These measures are: 1. wave reducing barriers, 2. water level fluctuations, 3. capping of the sediment with sand, and 4. combinations of above. Critical shear stress of the sediments for resuspension (Vcrit), size distribution, and optical properties of the suspended material were quantified in the field (June 2009) and laboratory. Water quality monitoring data (2002–2009) showed that light attenuation by organic suspended matter in all lakes is high. Spatial modeling of the impact of these measures showed that in Lake Loosdrecht limiting wave action can have significant effects (reductions from 6% exceedance to 2% exceedance of Vcrit), whereas in Lake Nieuwkoop and Lake Reeuwijk this is less effective. The depth distribution and shape of Lake Nieuwkoop and Lake Reeuwijk limit the role of wind-driven resuspension in the total suspended matter concentration. Although the lakes are similar in general appearance (origin, size, and depth range) measures suitable to improve their ecological status differ. This calls for care when defining the programme of measures to improve the ecological status of a specific lake based on experience from other lakes.

A Cognitive Model of an Epistemic Community: Mapping the Dynamics of Shallow Lake Ecosystems

We used fuzzy cognitive mapping (FCM) to develop a generic shallow lake ecosystem model by augmenting the individual cognitive maps drawn by 8 scientists working in the area of shallow lake ecology. We calculated graph theoretical indices of the individual cognitive maps and the collective cognitive map produced by augmentation. The graph theoretical indices revealed internal cycles showing non-linear dynamics in the shallow lake ecosystem. The ecological processes were organized democratically without a top-down hierarchical structure. The steady state condition of the generic model was a characteristic turbid shallow lake ecosystem since there were no dynamic environmental changes that could cause shifts between a turbid and a clearwater state, and the generic model indicated that only a dynamic disturbance regime could maintain the clearwater state. The model developed herein captured the empirical behavior of shallow lakes, and contained the basic model of the Alternative Stable States Theory. In addition, our model expanded the basic model by quantifying the relative effects of connections and by extending it. In our expanded model we ran 4 simulations: harvesting submerged plants, nutrient reduction, fish removal without nutrient reduction, and biomanipulation. Only biomanipulation, which included fish removal and nutrient reduction, had the potential to shift the turbid state into clearwater state. The structure and relationships in the generic model as well as the outcomes of the management simulations were supported by actual field studies in shallow lake ecosystems. Thus, fuzzy cognitive mapping methodology enabled us to understand the complex structure of shallow lake ecosystems as a whole and obtain a valid generic model based on tacit knowledge of experts in the field.Comment: 24 pages, 5 Figure

Session E2: Downstream Migration of 2+ Salmon Smolts (Salmo Salar) in the River Meuse in the Netherlands

Abstract: Downstream migration of 2+ salmon smolts (Salmo salar) was studied in the Meuse in the Netherlands, in the period 2009-2013. Smolts (n =897) with implanted NEDAP transponders, were released at different locations in the lower part of the Meuse in Belgium (Berwijn, Moelingen) and the upper part of the Meuse in the Netherlands (Stevensweert, Linne), and tracked by NEDAP trail stations at 41 fixed locations distributed along the Meuse and the Berwijn to the North sea (distance more than 300 km). Over the period 2009-2013 70% (n =628) of the smolts were detected. Numbers of smolts reaching the North sea varied per year, with a minimum of 0% and a maximum of 15% of the detected fish. The route prevailingly used to migrated to sea by way of the Haringvliet. Duration of smolt migration was mostly less than one month, with average migration speeds always below 1.2 m/s. The influence of the hydro power station (HPS) Linne on the migration was examined. Yearly mortality per km of smolts, over the river stretch Linne – Lith (130 km) turned out to be higher especially in a short distance downstream of the HPS, indicating a vulnerability of the species which is higher for passing the hydropower station than for passing the weir. Also attention was paid on losses by predation of Cormorants

Atomic Excitation Caused by α-Decay of the Nucleus

The prevailing theory of Migdal for predicting the excitation probabilities of an atom from α-decay of the nucleus, considers the α-particle, after it has been emitted by the nucleus, as following a classical trajectory and interacting with the atom quantum mechanically. Recently an attempt was made to properly model this quantum mechanical phenomenon, in one dimension, with a quantum wavefunction treatment of the decaying α-particle, but a discrepancy was found between the new predictions and that of the traditional method. In light of this discrepancy, we have studied the various approximations made in that work. Our results concur with recent follow up work suggesting that agreement should be found between a fully quantum mechanical model and with the classical model of α-particle propagation where the α-particle is treated as a point particle.ThesisMaster of Science (MSc

Interaction and evolutionary algorithms

Evolution and Interaction are two processes in Computer Science that are used in many algorithms to create, shape, find and optimize solutions to real world problems. Evolution has been very successfully applied as a pow-erful tool to solve complex search problems in fields ranging from physics, chemistry and biology all the way to commercial application such as aircraft fuselage design and civil engineering grading plans. Defining interaction is a big part of algorithm design. Not only defining the inputs and outputs of an algorithm but for a complex algorithm the interactions inside of an al- gorithm are as important. This thesis will concentrate on where Evolution overlaps Interaction. It will show how evolution can be used to evolve in- teraction, how the interaction inside an evolutionary algorithm impacts its performance and how an evolutionary algorithm can interact with humans. By touching on these three forms of overlap this thesis tries to give insight into the world of evolution and interactionThis work is part of the research programme of the Foun-dation for Fundamental Research on Matter (FOM), which is part of the Netherlands Organisation for Scientific Re-search (NWO). FOM Project: An evolutionary approach to many-parameter physics, project nr.: 03TF78-2, werkgroep FOM-L-24UBL - phd migration 201