Abundances and biological traits of the juveniles lamprey sampled in the survey of lamprey abundance Indice on the Oir river (France)

A survey started in 2009 is conducted every year in autumn (late September to early October) to quantify the abundance of juvenile lamprey in the Oir river in Normandy. This method uses a rectangular dredge to sample a constant and small surface of sediments in soft substrate areas. It targets all lamprey species. The data consist of abundance indices and biological traits measured on the fish sampled:length and weight. 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.