Synthèse sur les connaissances disponibles sur les migrateurs en mer: Rapport d'étape 1

Very little is known about diadromous fish distribution at sea. Twelve diadromous fish have been found to occur in France. However, numerous species have declined in recent years. Here, we collated a database of 168 904 hauls from 42 fisheries dependent and independent surveys between 1965 and 2019 and analyse data containing information on diadromous fish known to occur within French marine waters. The aim of this study is to 1) evaluate the use of the existing databases to study diadromous fish, 2) improve understanding of diadromous fish ecologyat sea, 3) assess the value of marine protected areas for diadromous fish, and 4) evaluate the risk of capture of diadromous fish from the different surveys and gear types