| Poster PS56A | |
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| Janice Kielbassa |
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| Laboratory of Biometry and Evolutionary Biology, University Claude Bernard Lyon 1 (France) |
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| Title | A temperature-dependent von Bertalanffy growth model applied to bullhead (Cottus gobio) |
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| Abstract | Global change, in particular climate warming is known to have a strong impact on aquatic populations. Water temperature is one of the most important environmental factors for the life cycle of fish due to direct effects on growth, survival and reproduction. In this respect, understanding and modelling of temperature effects on life-history characteristics of aquatic organisms can significantly contribute to ongoing attempts to predict climate-change effects at population and community levels. The most studied growth model among length-age models in fish is the von Bertalanffy equation. Although the von Bertalanffy equation is a suitable descriptor for length-at-age data, it can not be used to predict fish growth given changing environmental conditions. The main objective of our study was thus to propose a temperature-dependent form of the von Bertalanffy growth model. We included mean annual water temperatures in the von Bertalanffy growth equation by correlating the growth coefficient and the growth performance with the water temperature. The growth coefficient was related to temperature via Rosso's equation, and the growth performance was related to temperature via an increasing linear equation. These relationships included parameters with an obvious biological relevance that facilitated their identification. The asymptotic length was also linked to the water temperature via the growth performance that related the growth coefficient and the asymptotic length. We used our model to fit growth data of bullhead (Cottus gobio). The population we studied was that living in different locations of the River Bez network (France); this species appeared to be particularly sensitive to temperature fluctuations and field sampling sites along the river network corresponded to different mean annual temperatures. We proposed different assumptions to describe temperature correlations between parameters leading to several competing von Bertalanffy growth models. Graphical analyses as well as rigorous statistical methods and model selection criteria were combined to compare, to evaluate and to validate our models. We showed that our temperature-dependent growth model was an appropriate descriptor for the data set. Furthermore, we showed that this model fitted significantly better than other tested models assuming no dependency between temperature and the growth coefficient as well as between temperature and the growth performance. Such a temperature-dependent model may have broad implications if applied to data sets from other river networks or other species. |
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| Coauthors | Marie Laure Delignette-Muller, Sandrine Charles |
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| Location | Woodward Lobby (Monday-Tuesday) |
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