ESR 29:59-68 (2015)  -  DOI: https://doi.org/10.3354/esr00702

The Endangered Ganges River dolphin Platanista gangetica gangetica in Nepal: abundance, habitat and conservation threats

Shambhu Paudel1,2,*, Prabhat Pal2, Michael V. Cove3, Shant Raj Jnawali4, Grant Abel5, John L. Koprowski6, Rishi Ranabhat7

1Kathmandu Forestry College, PO Box 8973, Kathmandu, Nepal
2The Himalaya, Kathmandu, Nepal
3Department of Applied Ecology, North Carolina State University, Raleigh, North Carolina 27695, USA
4Hariyo Ban Program, World Wildlife Fund (WWF-Nepal), Kathmandu, Nepal
5Ocean Park Corporation, Hong Kong
6Wildlife and Fisheries Science, School of Natural Resources and the Environment, University of Arizona, Tucson, Arizona 85721, USA
7Department of National Parks and Wildlife Conservation, Kathmandu, Nepal
*Corresponding author:

ABSTRACT: Conservation of the last remaining Ganges River dolphins Platanista gangetica gangetica in Nepal will require robust population estimates and better information on suitable habitat characteristics. To gain a better understanding of these parameters, we conducted boat-based surveys in the 3 major river systems (Karnali, Sapta Koshi, and Narayani) of Nepal. We recorded covariates at high spatial resolution and utilized these data to inform occurrence and abundance models. We allowed for detection bias by applying occupancy and N-mixture models that account for imperfect and heterogeneous detection. Occupancy results indicate that dolphin site use varies among the different river systems, across 2 seasons, and increases with river depth. River effects received nearly 100% of the model support and had the strongest influence on dolphin occurrence and abundance. The seasonal influence on dolphin occurrence in the systems (Σωi = 0.997) revealed that occupancy probabilities were heightened during the pre-monsoon season. Deep pool habitat was also identified as a predictor of dolphin habitat use, which accounted for 41.02% of all dolphin sightings occurring in this habitat. Although estimates vary depending on season, we estimate that there are between 37 and 42 (95% CI: 28 to 52) Ganges River dolphins distributed in the rivers of Nepal. Results suggest that seasonality and each specific river affect dolphins and their habitat in Nepal; we strongly recommend site and season-specific conservation actions. Further research on the integration of additional and alternative abundance techniques, behavioral studies, and pursuit of a conservation genetics approach are all important steps in the management of this endangered species.


KEY WORDS: Ganges River dolphin · Endangered species · Abundance · Habitat · Distribution · Nepal


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Cite this article as: Paudel S, Pal P, Cove MV, Jnawali SR, Abel G, Koprowski JL, Ranabhat R (2015) The Endangered Ganges River dolphin Platanista gangetica gangetica in Nepal: abundance, habitat and conservation threats. Endang Species Res 29:59-68. https://doi.org/10.3354/esr00702

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