Abundances and biological traits of the juveniles salmon sampled in the survey of Salmon abundance Indices in the Oir river (France)

A survey started in 1993 is conducted every year in early autumn (late
September to early October) to quantify the abundance of juvenile
Atlantic salmon in the Oir In Normandy. The electric fishing protocol
of Prévost and Baglinière (1995) is used. It targets Atlantic salmon
young of the year (0+ parr), but older fish (juvenile salmon ≥1+) are
also caught and included in this dataset. Sampling is restricted to
areas with shallow running water flowing on coarse bottom substrate,
i.e. the preferred habitat of young of the year salmon. The data
consist of abundance indices and biological traits measured on the
fish sampled: sex, maturity status, length, weight and age. The latter
is ascertained from scale samples taken from the fish which size does
not allow to determine their age unambiguously. The survey is carried
out under the Research Observatory on Diadromes Fishes in Coastal
Streamss (ERO DiaPFC) program. The data are stored in the database of
the ERO. They are used to develop predictive models and tools for
providing scientific advice to improve the management of this heritage
species.