Internship position : Title: Modeling the hydraulic impact of river obstacles on the physical environment of migratory fish

You will be welcomed in the FREEMA research team (Functioning and Restoration of Estuarine Ecosystems and Diadromous Migratory Fish), within the EABX unit (Aquatic Ecosystems and Global Change). Your mission will be carried out within the framework of the DEBBARRAGE research project, funded by the French Nouvelle-Aquitaine region.  You will help formally represent the hydraulic consequences of obstacles to fish migration in order to produce scenarios of environmental perturbations to be used in simulations of  individual-based bio-energetic models.  Scientific Background Man-made obstacles do not only alter river continuity (Baudoin et al., 2014; Van Puijenbroek et al., 2019),but also alter other environmental conditions such as temperature, flow speed, water level, and turbulence, in a season- and flow-dependent manner. Hence, in order to understand how obstacles impact fish migration, it is important to move beyond binary alternatives (passage or non-passage) and consider how they modify the hydrodynamics in ways that affect the fish. Depending on these effects, a given obstacle may force a brief but intense locomotory effort on the fish, delay its migration, prevent recovery from previous efforts or increase mortality risks (Croze, 2008.; Haro et al., 1998). To study these effects, it is necessary at first to draw a systematic and quantitative picture of the modifications induced by obstacles on local hydraulics parameters. You will focus on those parameters that will be used subsequently in an energetic model of fish migration that is currently under development in our research team. Supervision and collaborations The internship will be co-supervised by Paul Benne (PhD student at Bordeaux University) & Mehdi Cherif (Researcher at INRAE), and integrated into an ongoing project about obstacle effects on fish migration and energetics.  You will also collaborate with Charlotte Récapet, associate professor at  the University of Pau & Pays de l’Adour. Other collaborations will happen as needed with members of the research team FREEMA , as well as an involvement in the research unit day-to-day activities. Scientific aims  The main goal is to identify the environmental variables that are modified by man-made obstacles and that affect fish migration in rivers. These patterns of hydraulic alterations will then be translated into different migration scenarios that will be fed into an individual bio-energetic model to calculate the additional energetic costs of obstacles. Milestone objectives will be set, i.e., you will:  Conduct a literary review to identify:  What are the hydraulic parameters that are modified by obstacles and that impact fish migration (e.g., water velocity, depth, discharge or turbulence).  What properties of obstacles are necessary in order to estimate these effects. Conduct an exploratory analysis of the mechanisms linking the selected hydraulic parameters and obstacle properties under various seasonal and flow-rate variations. Put forward generic mathematical formulations linking hydraulic parameters and obstacle properties. Identify scenarios for typical migration routes involving obstacles. Main tasks Search for, select, and organize the relevant information gathered from the scientific literature. Interpret and eventually analyze open-access data linking obstacles and hydraulic parameters. Conceptualize and model the impact of obstacles on the river local hydraulics. Compare and classify obstacles based on their hydraulic impacts. References  Baudoin, J.-M., Burgun, V., Chanseau, M., Larinier, M., Ovidio, M., Sremski, W., Steinbach, P., & Voegtle, B. (2014). Informations sur la Continuité Ecologique—ICE (Comprendre pour agir, p. 200). ONEMA. Croze, O. (s. d.). Impact des seuils et barrages sur la migration anadrome du saumon atlantique (Salmo salar L. ). Haro, A., Odeh, M., Noreika, J., & Castro-Santos, T. (1998). Effect of Water Acceleration on Downstream Migratory Behavior and Passage of Atlantic Salmon Smolts and Juvenile American Shad at Surface Bypasses. Transactions of the American Fisheries Society, 127(1), 118‑127. https://doi.org/10.1577/1548-8659(1998)127%3C0118:EOWAOD%3E2.0.CO;2 Van Puijenbroek, P. J. T. M., Buijse, A. D., Kraak, M. H. S., & Verdonschot, P. F. M. (2019). Species and river specific effects of river fragmentation on European anadromous fish species. River Research and Applications, 35(1), 68‑77. https://doi.org/10.1002/rra.3386