Habitat use and conservation Threats of Otters in the western bend of Karnali River, Nepal

Abstract

Otters are carnivorous mammals in the family Mustelidae. They face many conservation challenges, including habitat loss, pollution, lack of resources, illegal hunting and trade. Three species of otters- the Eurasian otter (Lutra lutra), the smooth-coated otter (Lutrogale perspicillata), and the Asian small-clawed otter (Aonyx cinerea) are recorded from Nepal. Due to limited studies, baseline information on otters is lacking for most of the wetland sites in Nepal. This study investigated the habitat use and conservation threats of otters in the Western Bend of the Karnali River in western Nepal. Otter distribution was surveyed using direct observations and recording indirect signs, such as scat, pugmarks and food remains, environmental and anthropogenic variables potentially affecting their occurrence were also recorded in the field. Logistic regression model identified key habitat factors influencing otter occurrence, including river width (CI -4.36–0.62, P < 0.05), water current (CI = -2.35 to -0.8, p < 0.05), and substrate type width (CI 0.49–2.12, P < 0.05). Results indicate that otters prefer narrower river sections with small stone bank substrates and moderate water flow, while avoiding areas with high human density (CI -10.15– -3.12, P < 0.05) and domestic dog presence (CI 0.95–4.94, P < 0.05). Conservation threats such as habitat degradation, illegal fishing, and human encroachment were documented from the study area. The study highlights the need for targeted conservation efforts, including habitat protection and community-based program to mitigate human activities as well as dog-otter conflict, to ensure the long-term survival of otters in this ecologically significant region. Findings provide baseline data for future monitoring and management initiatives.