We propose a matrix population modelling
approach in order to describe the dynamics of a grayling
(Thymallus thymallus, L. 1758) population living in the Ain
river (France). We built a Leslie like model, which integrates the
climate changes in terms of temperature and discharge. First, we
show how temperature and discharge can be related to life history
traits like survival and reproduction. Second, we show how to use
the population model to precisely examine the life cycle of
grayling : estimated numbers of individuals at the beginning of
the reproduction season, estimated number of individuals in
summer, comparison between observed and simulated numbers of
individuals. Finally, we discuss our results in the framework of
the assessment of impact of possible climate changes on grayling
populations.