Phenology and biological traits of migrating eels sampled by trapping in the survey in the Bresle river (France)

Since 1982, migratory eels have been captured on the Bresle basin, first as a bycatch from salmonid trapping, then to observe migration phenology and quantify their abundance. 15 km from the river estuary a trapping system controls silver eels migration for a period of 6 months per year (3-6 months per year historically) and since 1994 an upstream trap captures yellow eel in their upstream migration 3 km from the estuary. On the occasion of the capture, biometric characteristics are taken to characterize the population in order to feed this data set.