Widespread all over the country till the end of the last century, the otter has rapidly declined. In 1973 when hunting was definitely closed, the otter was already threatened and restricted to a few localities. In 1889, the Belgian Ministry of agriculture decided to pay bounties for otters, a system which was cancelled only in 1963. Game statistics of the past century allow the annual otter bag to evaluated as roughly 25 % of the standing population. As it is the case in other European industrialised countries, freshwater habitat loss and water pollution lead to a considerable decrease of the river carrying capacity. Almost all the rivers flowing in the Northern part of Belgium are now lifeless or at least in a very bad condition. South of the river Meuse, some accidental pollutions are regularly reported (chloring in the river Ourthe in 1993; chloracetic acid in the Sûre in 1990.) and the level of organic pollution rises from year to year. Moreover, the tourism (angling, camp sites, kayak) nare more and more intensive leading to major disturbances, particularly during the summer months. Finally, the Ministery of equipment is developing a policy of big hydraulic works (dams, embankments, dredging.) along the river Ourthe, one of the last to be occupied by a few otters.