Determinants of Smooth-coated Otter (Lutrogale perspicillata) Latrine Occurrence and Diet in the Karnali River, Nepal.

Smooth-coated Otter (Lutrogale perspicillata) depends on riverine prey and bank habitat for foraging and scent-marking, but evidence from the large, braided rivers in Nepal is limited. We assessed habitat correlates of latrine presence patterns and diet composition of Smooth-coated Otter in the lower section (39 km) of the Karnali River. Latrine presence-absence was surveyed across 70-belt transects distributed along both banks of the river with 21.43% presence and modelled using generalised linear model (binomial) with river characteristics. Diet analysis was done through hard-component analysis of 32 spraints and spraint placement was examined with measured distance from river and substrate type. The presence of latrine sites decreased with increasing proximity to settlement, river width and water velocity, and was lower at sites with a retaining wall. Spraint placement analysis showed that higher spraint counts were observed with increasing distance from river (r = 0.481, p = 0.0046) and the highest count on sand substrate. Diet from spraint analysis revealed dominance of fish species followed by crabs and birds. Fishing net was observed in 46.9% of analysed spraints, indicating frequent interaction with fishing gear. Our findings suggest that maintaining escape cover, limiting bank modification and reducing fishing gear exposure should be prioritised to improve habitat suitability and to reduce emerging threats in the Lower Karnali River.