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Elsevier, Biological Conservation, 4(129), p. 579-590, 2006

DOI: 10.1016/j.biocon.2005.11.026

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Status assessment of the Indus River dolphin, Platanista gangetica minor, March–April 2001

Journal article published in 2006 by Gillian T. Braulik ORCID
This paper is available in a repository.
This paper is available in a repository.

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Data provided by SHERPA/RoMEO

Abstract

A survey was conducted in March and April 2001, to assess the status of the Indus River dolphin, Platanista gangetica minor, throughout its present range. A total of 1535km of survey effort was conducted, consisting of 1375km of the Indus River main channel, 136km of Indus River secondary channels, and 24km of the Panjnad River, a tributary of the Indus. The effective range of the Indus dolphin has declined by 80% since 1870. The sum of best group size estimates produced an abundance estimate of 965 dolphins. Extrapolation of encounter rates to un-surveyed channels and application of a correction factor to account for missed dolphins indicates that the metapopulation may number approximately 1200 individuals. Dolphins occur in five subpopulations separated by irrigation barrages. A pronounced increase in dolphin abundance and encounter rate was observed in each subsequent downstream subpopulation (except the last). The three largest subpopulations were between Chashma and Taunsa Barrages (84 dolphins; 0.28/km), Taunsa and Guddu Barrages (259 dolphins; 0.74/km) and Guddu and Sukkur Barrages (602 dolphins; 3.60/km). Reasons suggested for the high encounter rate between Guddu and Sukkur Barrages, include high carrying capacity, low levels of anthropogenic threat, effective conservation, and augmentation of the subpopulation by downstream migration of dolphins from upstream.