Download Indus River dolphins in Pakistan

Indus River dolphins in Pakistan
© Gill Braulik
Gill Braulik is is working on two projects in Pakistan, focusing on the
Indus River dolphin.
Location: - Indus River, Pakistan
Species: - Indus River dolphin
Researcher: - Gill Braulik
The Indus (Platanista gangetica minor) and Ganges
(Platanista gangetica gangetica) river dolphins
occur only in freshwater in the separate Indus and
Ganges-Brahmaputra river systems in South Asia.
Both subspecies are listed as ‘Endangered’ by the
World Conservation Union (Braulik et al., 2004;
Smith et al., 2004), and they are among the world’s
most endangered dolphins. Both river dolphin
populations are severely fragmented by dams
and barrages, have suffered enormous (50-80%)
range declines in the last hundred years and
are threatened by declining freshwater supplies,
pollution, capture in fishing nets and hunting. The
subspecies are the only members of the Genus
Platanista which is a very primitive and ancient
cetacean group only distantly related to modern
Delphinids.
Background to the project
Despite their relatively high profile as endangered
dolphins very little is known about these animals
and there is confusion and uncertainty about their
taxonomy. On the basis of very little morphological
information the accepted classification of these
river dolphins has changed multiple times from
subspecies to separate species and back again. The
reclassification in 1998 of the two dolphin populations
from species to subspecies has caused confusion in
south Asia where the dolphins occur, has reduced
the perceived importance of the Indus dolphin
inside Pakistan and may have negatively impacted
conservation efforts by lowering their priority for
allocation of international funds.
At the ‘Workshop on the Shortcomings of Cetacean
Taxonomy in Relation to Needs of Conservation and
Management’ held in 2004 clarification of the taxonomy
The team on board the survey boat on the Indus River.
of Platanista was listed as high priority by this expert
group because the two putative species are severely
threatened and occur in only one or a few countries
“Improved
clarity with
regard to their
systematics will
have important
implications for
their conservation
and management”
(Reeves et al., 2004). Improved clarity with regard to
their systematics will have important implications for
their conservation and management.
© Albert Reichert
History of the River systems
The Indus River dolphin is thought to be highly endangered.
The Indus and Ganges-Brahmaputra River systems
have existed for at least 40 million years and evidence
suggests they have been largely separate for at least
five million years. Although the Indus and Ganges are
ancient rivers, historically rivers near the Indus-Ganges
drainage divide have been captured repeatedly and it
is possible that there was faunal exchange between
river systems even in relatively recent times. The
fish fauna is similar between the two river systems,
however there has been speciation of some catfish
and carp species.
The Study
One of the reasons that no comprehensive study on
the taxonomy of Platanista has been conducted to
date is the difficulty of a collaborative study between
Pakistan (home of the Indus dolphin) and India (home
of the Ganges dolphin) due to the political situation
in the region and problems with exporting samples to
another location for analysis. With the fairly recent
advent of DNA extraction from bone there is now an
opportunity to use museum specimens in the west
to obtain DNA for a comparative molecular study
which will allow long overdue resolution regarding the
relationship between these closely related populations.
Samples will be taken from Indus and Ganges
dolphin skeletons stored in natural history museums
in the UK, USA, Germany and Pakistan and DNA
extraction, sequencing and analysis will be conducted
at the Molecular Ecology Laboratory at the University
of Durham which has facilities for extraction of ancient
DNA.
Unique haplotypes, variable sites and the
number of base-pair differences will be identified
and compared between populations and statistical
analyses conducted on the data to determine whether
there are sufficient differences between populations to
classify them as separate species.
1
© Gill Braulik
water sources particularly the Indus River. Available
water per capita is plummeting and is approaching
1000 cubic meters per person down from 5600 cubic
meters per capita in 1947. The country is entering a
water crisis and as its greatest source of freshwater
is the Indus River system there are numerous plans
to further exploit the River by constructing dams and
increasing water diversion with little consideration of
the environmental and social impacts this may cause.
The problem is further exacerbated by climate change;
reduced glacial cover and weakening monsoon rains in
northern Pakistan are predicted to dramatically reduce
Indus River discharge within 50 years. Declining river
flows have been highlighted as perhaps the greatest
threat to the long-term survival of the Indus River
dolphin (IWC., 2001).
Survey boat with the Guddu Barrage in the background. The proliferation of river dams
are damaging the long-term survival prospects of all river dolphin species.
Location: - Indus River, Pakistan
Species: - Indus River dolphin
Researcher: - Gill Braulik
The Indus River dolphin (Platanista gangetica
minor) is one of the world’s most threatened
cetaceans. It occurs only in freshwater, in the
mainstem of the Indus River and it is endemic
to Pakistan. Dolphins are found in primarily 3
subpopulations separated by irrigation barrages
(low, gated-dams). The populations are estimated
as 602 (Guddu-Sukkur), 258 (Taunsa-Guddu
barrages) and 84 (Chashma-Taunsa barrages)
individuals. The metapopulation was estimated
to number approximately 1200 animals in 2001
(Braulik, 2006).
Background to the project
© Albert Reichert
The Indus is a highly managed river and during the
dry season all of its flow is diverted for irrigation and
municipal uses. For several months of the year largescale water extraction causes the river downstream of
Hyderabad to be completely dewatered (i.e. dry) before
reaching its delta. This large-scale and increasing
diversion of water from the Indus River has severally
reduced the quantity of dolphin habitat and is the
primary reason for its extirpation from 80% of its former
“Declining river
flows have been
highlighted as
perhaps the
greatest threat
to the longterm survival of
the Indus River
dolphin”
range. The remaining dolphins are concentrated into
the only section of the Indus River that is consistently
flowing throughout the year. Pakistan is one of the
most water stressed countries on earth, its semi-arid
climate combined with large (167 million in 2006) and
rapidly expanding (2.09%) population are placing
enormous and unsustainable pressure on existing
Project Aims/Objectives
This project aims to understand which hydrological
habitat (depth and velocity) dolphins depend
upon in the dry season. This information is vital to
understanding the impact of decreasing river flows
on dolphins, will provide valuable information for
managing the dolphin population and for lobbying the
government and water management authorities to
maintain sufficient water in the river for a functioning
ecosystem which includes dolphins.
Methodology
Three intensive study sites approximately 1km in
length will be selected for this study. A GPS integrated
depth sounder will be used to comprehensively map
the depth of the site. Water velocity will be measured
using a Marsh-McBirney Flo-Mate velocity meter
deployed from an anchored dingy. Velocity will be
measured at standard intervals in the water column
on cross sections perpendicular and parallel to the
river flow and a GPS position will be recorded to
geo-reference each record. Data will be processed
using a Geographic Information System (GIS) to create
three dimensional depth and velocity maps for each
study site in each flow state. The spatial distribution
of dolphins within each intensive study site will be
recorded over a two week period from a number of
bank-based observation points. Data will be spatially
analysed using GIS software and each dolphin record
will be assigned a depth and velocity according to its
surfacing position. Finally Generalised Linear Models
will be used to examine statistically the relationship
between the spatial distribution of dolphins and the
hydrological variables in the study site.
© WDCS
Created by WDCS UK
Brookfield House, 38 St Paul Street,
Chippenham, SN15 1LJ
T: +44 (0)1249 449500
Registered charity no: 1014705
www.wdcs.org
Gill Braulik working in the field.
2
Offices in Argentina, Australia, Germany, UK and USA