Predicting downstream migration of silver eels in a large river catchment based on commercial fishery data

• Main Authors: Durif, C., Elie, P.
• Other Authors: INSTITUTE OF MARINE RESEARCH OSLO NOR, CEMAGREF BORDEAUX EPBX
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2008
• Subjects: ANGUILLA ANGUILLA; MIGRATION; DYNAMIQUE DE POPULATION; ESPECE MENACEE; ENDANGERED SPECIES (IUCN); POPULATION DYNAMICS; Anguilla anguilla
• Online Access: https://irsteadoc.irstea.fr/cemoa/PUB00023964

Worldwide, populations of catadromous eels are in decline. Knowledge on downstream migration patterns is needed to mitigate damage caused by hydroelectric stations. Silver eel migration and its relation with environmental factors were investigated using data from a fishery located in the lower reaches of a large catchment (110 000 m2). Migration days, indicative of different proportions (50%, 75% and 95%) of the annual run of eels (i.e. represented by the annual catch), were predicted using discriminant analyses. Efficiency of prediction was 5895% depending on the proportion of the run targeted. The onset of migration was correlated with sunshine hours, August temperature and discharge. Julian days (i.e. photoperiod) was significantly correlated with migration days, indicating between-year similarity in the dynamics of the runs. The size of migrants varied within the migration season, reflecting differences in their initial spatial distribution.