The decline of otter Lutra lutra populations in the region of the pays de loire, Western France
Résumé
In the Pays de Loire region of western France, a field survey carried out between 1984 and 1991 showed that otter populations decreased over 54·2% of sites and are now highly fragmented. In 1991 only 9·5% of 348 sites produced positive records compared to 20·7% in 1984. The decline was most notable in the larger rivers whereas the relative use of marsh habitat increased. Populations become more vulnerable when riparian vegetation declines. Accidental drowning in eel Anguilla anguilla fyke nets appears to be the major cause of accidental mortality. The scarcity of otter populations is an indication of serious degradation of aquatic ecosystems.