– Population dynamics modelling; a first experience in individual-based modelling
would be an additional asset.
– Interest for programming.
– Knowledge in biological aquatic science would be appreciated.

Scientific context
Fish habitat use is a key driver of population dynamics (Hayes et al., 2009), essential
knowledge for predicting how populations are likely to respond to management rules (Koster
et al., 2015). The littoral zones of lakes host a high biodiversity (Schmieder, 2004) and
provide resources available nowhere else in the lacustrine ecosystem (Zohary and Gasith,
2014). Most fishes use them during their entire life cycle for feeding, refuge or reproduction
(Winfield, 2004). Reservoirs experience anthropogenic water level fluctuations (WLF) that
affect the littoral habitats and their availability. Then, through these effects on habitat, fish
fauna can be impacted in several ways by WLF: loss of refuge areas (Kaczka and Miranda,
2014), loss of spawning habitats (Hudon et al., 2005) and loss of potential prey (Winfield,
2004). Though statements on their impact are frequent, quantification of WLF effects on biological communities, at the littoral zone scale as well as on the entire reservoir scale, remains little documented (Wantzen et al., 2008).

Study site and data
The Bariousses reservoir (France) is a hydroelectric impoundment with WLF. Adult individuals of pike, perch and pikeperch have been tracked by acoustic telemetry for 2 years (a theoretical position every ~2min) (Roy et al., 2014). This monitoring resulted in hundreds of thousands of fish positions.
The physical environment of the entire site has been characterized: littoral habitats (substrate type and vegetation) and bathymetry were mapped; the water level and a temperature profile at the deepest point were continuously measured.

Post-doctoral objectives
The proposed work aims to develop a spatialized simplified fish population model. The objective is to identify the contribution of each environmental variable (littoral habitat, temperature and water level) on the global population dynamics of three fish species.
– In a first step, adult individual movement decision rules will be built for each species. This work will be based on the habitat preferences and movement characteristics of the three species inferred from the telemetry and habitat dataset (lots of results being already available in the laboratory) and completed by a detailed review and the collection of expert knowledge on the species life-history traits.
These rules will be implemented in an individual-based model to simulate fish movements over annual cycles (e.g. Baetens et al., 2013). This will be done in a in-house developed JAVA framework (SimAquaLife). This movement model will be rigorously validated with available data on the Bariousses reservoir.
– In a second step, the choice of spawning site by adults, the eggs and larvae survivals and the juvenile growth dependent on the habitat type (Clark et al., 2008) will be plugged in the model. This work will be based on the previous detailed review (e.g. Dahlberg, 1979; Doka, 2004; Jones et al., 2003; Souchon and Tissot, 2012) and expert knowledge.
– Finally, simulations will be run to test the effect of different hydrological management rules or climatic scenario on the three species population dynamics.

Supervising committee:
Samuel Westrelin (IRSTEA Aix-en-Provence, Main supervisor)
Laurence Tissot (EDF R&D Chatou, Main supervisor)
Patrick Lambert (IRSTEA Bordeaux, Main supervisor)
Christine Argillier (IRSTEA Aix-en-Provence, Fish ecologist)
Hervé Capra (IRSTEA Lyon, fish ecologist)
Nicolas Dumoulin (IRSTEA Clermont-Ferrand, Computer scientist)
Ine Pauwels (INBO Research Institute for Nature and Forest Bruxelles, Fish ecologist)

Application deadline : 22 october 2017
Starting date : January 2018
Duration : 18 months
Location: Irstea – UR RECOVER

This work is supported by HYNES research program conducted by Irstea and EDF R&D.
Possible travels to Chatou (Paris suburb) and Bordeaux for technical works with some
committee members are expected.

Gross monthly salary: 2 560 €/month
To apply, send a CV and a covering letter to [email protected] and
[email protected]

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