WWF survey of the entire range of the Indus River dolphin - 2001
Gill Braulik, WWF-Pakistan
Braulik, G. 2012. WWF survey of the entire range of the Indus River dolphin - 2001. Data downloaded from OBIS-SEAMAP (http://seamap.env.duke.edu/dataset/848) on yyyy-mm-dd.
Halpin, P.N., A.J. Read, E. Fujioka, B.D. Best, B. Donnelly, L.J. Hazen, C. Kot, K. Urian, E. LaBrecque, A. Dimatteo, J. Cleary, C. Good, L.B. Crowder, and K.D. Hyrenbach. 2009. OBIS-SEAMAP: The world data center for marine mammal, sea bird, and sea turtle distributions. Oceanography. 22(2):104-115.
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 1535 km of survey effort was conducted, consisting of 1375 km of the Indus River main channel, 136 km of Indus River secondary channels, and 24 km 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 unsurveyed channels and application of a correction factor to account for missed dolphins indicates that the metapopulation may number approximately 1,200 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.
Data contains information on both the detection location, which is the location of the boat when a dolphin was sighted, and also an exact location, which was the position of the boat when the dolphins were perpendicular. Exact locations were plotted but detection location was used if an exact location was not available.
BHL are best, high, low estimates of group size. Best estimates were used for the observed count.
Actual survey tracks followed the winding pattern of the Indus River. Tracks presented here are very approximate straight-line visual representations of the actual track. These visually indicate which river sections were surveyed but should not be used for any analysis.
Braulik, G.T. 2006. Status assessment of the Indus River dolphin, Platanista gangetica minor, March-April 2001. Biological Conservation. 129:579-590.
Braulik G.T., A.P. Reichert, T. Ehsan, S. Khan, S.P. Northridge, J.S. Alexander and R. Garstang. 2012. Habitat use by a freshwater dolphin in the low-water season. Aquatic Conservation: Marine and Freshwater Ecosystems. 22:533-546.
Attributes described below represent those in the original dataset provided by the provider.
This section explains attributes included in the original dataset. OBIS-SEAMAP restricts the attributes available to the public to date/time, lat/lon and species names/counts only. Should you need other attributes described here, you are encouraged to contact the data provider.
Attributes in dataset provided
|Rays and sharks||0|
|Latitude||25.51 - 32.78|
|Longitude||68.20 - 71.41|
|Coord. prec.||6 decimal digits|
|Data type||Animal sighting|
|Effort||YES (ID: 849)|
|Sharing policy||CC-BY-NC (Minimum)|
|Also availalbe from||iOBIS|
|See metadata in static HTML|
|See metadata in FGDC XML|
|See download history / statistics|