Population Fluctuation and Resource Protection of Otter(Lutra lutra) in Changbai Mountain Nature Reserve
长白山自然保护区水獭种群数量变动与资源保护

Abstract: From 1980 to 2010, we monitored the population,habitat and the food status of otter in Changbaishan National Nature Reserve in three main rivers by field route survey (investigating along river bank) and fixed spot investigation, then analyzed the influencing factors leading to be endangered. From 2006 to 2008, we investigated the population and habitat (non frozen river surface) of otter in 18 rivers in winter. The result indicates: The population of otter is decreased significantly since 1990 in Changbaishan National Nature Reserve and surrounding rivers, and is decreased by more than 99 percent compared to 1975. The Population variety of otter is significantly correlated to aquatic biomass variety (n=8.r=0.977, P<0.01). The size of non frozen river surface benefiting to feed for otter is decreasing due to human disturbance in winter. Because of several negative influences of human activities, such as excessively fishing, pesticide applying, dam construction, etc, many wild fish disappeared, caused food shortage, which bring on the population of otter decreased quickly and even locally depopulation. Especially, river pollution result from excessive using insecticide and herbicide is the key factor.