Modelling the migration opportunities of diadromous fish along a gradient of salinity and dissolved oxygen in the Zeeschelde estuary (Belgium)
Maes, J.; Stevens, M.; Breine, J.J. (2009). Modelling the migration opportunities of diadromous fish along a gradient of salinity and dissolved oxygen in the Zeeschelde estuary (Belgium), in: Breine, J. Fish assemblages as ecological indicator in estuaries: the Zeeschelde (Belgium) = Visgemeenschappen als ecologische indicator voor estuaria: de Zeeschelde (België). Doctoraten van het Instituut voor Natuur- en Bosonderzoek = PhD theses of the Research Institute for Nature and Forest, T.2009.1: pp. 86-107 In: Breine, J. (2009). Fish assemblages as ecological indicator in estuaries: the Zeeschelde (Belgium) = Visgemeenschappen als ecologische indicator voor estuaria: de Zeeschelde (België). Doctoraten van het Instituut voor Natuur- en Bosonderzoek = PhD theses of the Research Institute for Nature and Forest, T.2009.1. PhD Thesis. KU Leuven/INBO: Leuven. ISBN 978-90-403-0299-2. 263 pp., more In: Doctoraten van het Instituut voor Natuur- en Bosonderzoek = PhD theses of the Research Institute for Nature and Forest. Instituut voor Natuur- en Bosonderzoek, more |
| Keywords | Chemical elements > Nonmetals > Atmospheric gases > Oxygen > Dissolved gases > Dissolved oxygen
Fish
Migration
Models
Taxa > Species > Amphihaline species > Anadromous species
Water pollution
Belgium, Zeeschelde [Marine Regions]
Marine/Coastal; Brackish water; Fresh water |
| Abstract | The relationship between poor water quality and migration opportunities for fish remains poorly documented, although this knowledge is essential for a correct implementation of the EU water legislation. In this chapter, we model environmental constraints that control the movements of anadromous and catadromous fish populations that migrate through the tidal watershed of river Schelde, a heavily impacted estuary in Western Europe. Local populations of sturgeon, sea lamprey, sea trout, Atlantic salmon, houting and allis shad were essentially extirpated around 1900. For remaining populations (flounder, three-spined stickleback, twaite shad, thinlip mullet, European eel and European smelt), a data driven logistic model was parameterized. The presence or absence of fish species in samples taken between 1995 and 2004 was modelled as a function of temperature, dissolved oxygen concentration, river flow and season. Probabilities to catch individuals from all diadromous species but three-spined stickleback, increased as a function of the interaction between temperature and dissolved oxygen. The hypoxic zone situated in the freshwater tidal part of the estuary was an effective barrier for upstream migrating anadromous spawners since it blocked the entrance to historical spawning sites upstream. Similarly, habitat availability for catadromous fish was greatly reduced and restricted to lower brackish water parts of the estuary. The model was applied to infer preliminary dissolved oxygen criteria for diadromous fish, to make qualitative predictions about future changes in fish distribution given anticipated changes in water quality and to suggest necessary measures with respect to watershed management. |
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