Analysis of morphological and physiological parameters during the silvering process of the European eel (Anguilla anguilla) in the lake of Grand-Lieu (France)

• Main Authors: Durif, Caroline, Elie, Pierre, Dufour, S., Marchelidon, J., Vidal, B.
• Other Authors: Ressources aquatiques continentales (UR RABX), Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF), Muséum national d'Histoire naturelle (MNHN)
• Format: Article in Journal/Newspaper
• Language: French
• Published: HAL CCSD 2000
• Subjects: FRANCE; LOIRE ATLANTIQUE; GRAND LIEU LAC; [SDE]Environmental Sciences; Anguilla anguilla
• Online Access: https://hal.inrae.fr/hal-02579605

[Departement_IRSTEA]GMA [TR1_IRSTEA]12 - MILEAU / REPIGE National audience The aim of the current study was to describe the morphological and physiological changes, which occur during the transition from yellow to silver eel (Anguilla anguilla). We investigated the different stages present in an eel population prior to the downstream migration. We were thus able to observe the sequence of changes during the metamorphosis. Measurements were taken on 205 eels captured in the lake of Grand-Lieu (france). To evaluate the degree of metamorphosis, gonads, digestive tract, and liver were weighed and the level of gonadotropic hormone was measured. Principal component analysis was carried out on a subsample of eels for which we had all four physiological parameters in order to determine homogeneous groups according to their sex and degree of maturation. Thus, three groups were identified : the first one corresponding to male silver and intermediate eels, the second one, silver and intermediate females, and the third group yellow eels. Discriminant functions based on morphological variables were then calculated and used to reclassify individuals in their initial category. Eels were correctly reclassified at 94 %. These functions were then applied on the whole sample. Results of the classification were compared to initial data, allowing the identification of four different stages as well as the sequence of events during the beginning of the metamorphosis. L'objectif de cette étude a été de décrire de façon précise les différents stades d'anguilles (Anguilla anguilla) avant leur migration d'avalaison de manière à visualiser la succession des changements au cours de la transition anguille jaune - anguille argentée. Des mesures ont été effectuées sur 305 anguilles provenant du lac de Grand-Lieu (Loire-Atlantique). Afin d'évaluer le degré de métamorphose des anguilles, nous avons mesuré les poids des gonades, de l'intestion et du foie ainsi que la teneur en GtH. Une analyse en composantes principales a été effectuée sur ...