Data analysis issued from the survey of moving fauna near Braud et Saint Louis plant

• Main Authors: Lambert, Patrick, Pronier, Olivier, Rochard, Eric, Martin Vandembulcke, Delphine
• Other Authors: Ressources aquatiques continentales (UR RABX), Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF), irstea
• Format: Report
• Language: French
• Published: HAL CCSD 1997
• Subjects: CEMAGREF; RABX; FRANCE; AQUITAINE; GIRONDE; GIRONDE ESTUAIRE; BRAUD ET SAINT LOUIS CENTRALE; [SDE]Environmental Sciences; Anguilla anguilla
• Online Access: https://hal.inrae.fr/hal-02578491

A survey of the moving fauna near the Baud et Saint Louis plant (France) has been conducted since the end of the 70's. The resulting database allows us to determine the evolution of abundance of shad juvenile (Alosa alosa), white shrimp (Palaemon longirostris), and glass-eel (Anguilla anguilla) in the mesohaline sector of the Gironde estuary.Three main points can be highlighted : a decrease in shrimp stock, showing a lower density near the plant (right estuary bank) an increase in shad abundance associated with rising variability a glass-eel evolution in three steps, firstly, an important decrease at the beginning of the 80's, secondly, a low plateau from 1983 to 1991, and thirdly, a higher plateau since 1993. This database is key to propose hypotheses about the ecology of the populations studied. The fluctuations in shrimp abundance seems to mimic a predator-prey dynamic; the glass-eel distribution in the estuary shows the relationship between depth and animal density. The database also allows to invalidate others hypotheses like the directing function of the Saintonge bank in anadromous glass-eel migration. However, the limits of this database are demonstrated : data incorrectly filled in or partially missing, difficult interface with other databases, main predators not included in the survey. Un suivi de la faune circulante aux abords de la Centrale de Baud et Saint Louis est réalisé depuis la fin des années 70. Cette source d'informations, mise sur support informatique, nous a permis de suivre l'évolution de l'abondance des juvéniles d'aloses (Alosa alosa), des crevettes blanches (Palaemon longirostris) et des civelles d'anguilles (Anguilla anguilla) dans la partie mésohaline de l'estuaire de la Gironde. Ont été mises en évidence une tendance décroissante du stock de crevettes avec des densités plus faibles en rive droite au niveau de la centrale, une augmentation des abondances des alosons associée à une variabilité croissante et des quantités de civelles qui connaissent une chute brutale au début des ...