Modélisation bioénergétique de la variabilité des traits d’histoire de vie de l’anchois et de la sardine entre le golfe du Lion, le golfe de Gascogne et la Manche
Small pelagic fish show a general decrease in size and body condition over the past two decades in the North-East Atlantic. The underlying factors are still not well understood, however recent studies point to a bottom-up control. In order to understand how the environment impacts the main biologica...
| Main Author: | |
|---|---|
| Format: | Report |
| Language: | French English |
| Published: |
2020
|
| Subjects: | |
| Online Access: | https://archimer.ifremer.fr/doc/00667/77900/80092.pdf https://archimer.ifremer.fr/doc/00667/77900/ |
| Summary: | Small pelagic fish show a general decrease in size and body condition over the past two decades in the North-East Atlantic. The underlying factors are still not well understood, however recent studies point to a bottom-up control. In order to understand how the environment impacts the main biological functions, i.e. growth, reproduction and maintenance, we adopted a bioenergetic modelling framework based on the Dynamic Energy Budget theory. To improve the robustness of our study, we chose a comparative approach between two species, Engraulis encrasicolus and Sardina pilchardus, both living in three areas, namely the English Channel, the Bay of Biscay and the Gulf of Lion. Our model is calibrated over the Bay of Biscay and then applied to the other areas, over the early 2000s and the mid-2010s. The environment alone, temperature and zooplankton, explained well the observed spatial differences in growth. The Gulf of Lion had a lower fit than the other areas, which might suppose local genetic adaptation. However, we could not highlight any significant trends between 2000 and 2015 in the environmental data we used. Thus, no significant differences have been observed in the model's outputs between the early 2000s and the mid-2010s. This could result either from the lack of interannual variability in our environmental data, and/or from a change occurring on a finer scale, such as a change in the size of zooplankton or a change in the structure of zooplankton's communities. Les petits poissons pélagiques de l'Atlantique nord-est montrent une baisse de taille et de condition au cours de ces vingt dernières années. Les processus sous-jacents ne sont pas clairement définis, cependant des études récentes mettent en avant à un contrôle bottum-up. Afin de comprendre comment l’environnement impacte les principales fonctions biologiques, i.e. croissance, reproduction et maintenance, nous avons utilisé un modèle bioénergétique basé sur la théorie Dynamic Energy Budget. Afin d'améliorer la robustesse de notre étude, nous ... |
|---|