Species conservation target for freshwater fishes inhabiting Bengal sub-tropical montane rivers of Eastern Himalayas: an indexed value approach for priority determination.

Identifying conservation strategy is essential regarding prioritization, planning, and managing biodiversity. The Eastern Himalayan freshwater reaches contain diverse taxa of fish species. Despite having several coarse scales of assessment, the information regarding the fine-scale conservation priorities is scanty. The development of indices from multimeric attributes has been proved efficient, aiding conservation planning, in-depth research, exploitation, policy-making, and public awareness. Therefore, this study aims to provide detailed indexing of conservation values for the freshwater fish species inhabiting the sub-Himalayan Terai–Dooars ecoregion of the Eastern Himalayas. Based on three years of extended sampling in six freshwater reaches, 170 indigenous fish species were identified. Each fish species was assigned a discrete conservation value following their rarity, taxonomic singularity, contribution to β diversity, global threat status, regional importance, and maximal achievable body lengths. Neolissochilus hexagonolepis has the highest conservation value. In contrast, the lowest values were observed for Pethia gelius, Pethia guganio, and Pethia phutunio. The freshwater habitats of upper and lower elevation harbor essential fish species for conservation, driven by precipitation, topographic, and land cover variability. Such results were accomplished through spatial interpolation and prioritization regarding fish conservation, protection, and vulnerability toward the human footprint for this region of the Eastern Himalayas. [ABSTRACT FROM AUTHOR]