Ganges river dolphins and other biodiversity in the Mahananda River in Bihar and West Bengal: A report on the first complete survey, November 2021. Report for the Department of Environment, Forests, and Climate Change, Government of Bihar. Wildlife Conservation Trust, Mumbai, India, 35 pp.

Full text

1
Ganges river dolphins and other biodiversity in the
Mahananda River in Bihar and West Bengal
A Report on the First Complete Survey, November 2021
Submitted to
The Chief Wildlife Warden
Department of Environment, Forests, and Climate Change
Government of Bihar
by
Dr. Nachiket Kelkar and Subhasis Dey
Riverine Ecosystems And Livelihoods programme
Wildlife Conservation Trust

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Survey Team
Team Leaders
Subhasis Dey, Nachiket Kelkar
Field assistance
Akshay Kumar, Ravindra Kumar, Soumen Bakshi
Vehicle support
Shamsher Khan, Irfan
Cover image: Soumen Bakshi, WCT.
Citation: Kelkar, N. & Dey, S. 2021. Ganges river dolphins and other biodiversity in the
Mahananda River in Bihar and West Bengal: A report on the first complete survey,
November 2021. Report for the Department of Environment, Forests, and Climate Change,
Government of Bihar. Wildlife Conservation Trust, Mumbai, India, 35 pp.
Supporting Institutions
Department of Environment, Forests, & Climate Change, Government of Bihar

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Executive Summary
Our report presents the first ever population estimate of endangered Ganges river
dolphins for the Mahananda River in India. The Mahananda, until now, remained the only
major Indian river where Ganges dolphins were known to be present, but whose status had
never been assessed even once for the entire stretch. In our survey, we covered 250 km
over 10 days in November 2021 and counted 190 individual dolphins from two kayaks.
Statistical analysis of our tandem boat survey data provided a population estimate of 232 ±
11 (mean ± standard deviation) Ganges river dolphins, i.e. 0.93 dolphins/km of river. The
Mahananda thus harbours a significantly large resident and breeding population of Ganges
river dolphins. Our survey report fills a major gap knowledge gap about the status of Ganges
river dolphins in the Mahananda river in Bihar and West Bengal, and provides baseline
information that completes range-wide population status figures for India.
To describe river dolphin habitat and potential human impacts, we provide details of
river flow and depth conditions, flooding patterns, status of capture fisheries, and potential
impacts of other human activities, especially sand mining, on riverine biodiversity.
Additionally, we have included a checklist of 123 species of birds seen in the river-floodplain.
River dolphin distribution showed strong association with deep pools formed near bridges
and river training sites along embankment spurs. These sites were important fishing spots,
leading to dolphins and fishers aggregating in the same habitats. Fisheries in the
Mahananda displayed remarkable diversity of nets and gears, and fishing intensity in most
areas was related to fishing lease arrangements in different districts. We heard anecdotal
reports of recent river dolphin mortality in fishing nets in all three districts of Bihar –
Kishanganj, Purnia, and Katihar. Intensive sand mining was recorded in upstream reaches.
We conclude the report by providing some recommendations both for future research
and conservation interventions in the Mahananda River, based on our results and
documentation. We strongly believe that the report will be a valuable information resource to
the Bihar State Department of Environment, Forests, and Climate Change.

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Acknowledgments
We sincerely thank the Department of Environment, Forests, and Climate Change,
Government of Bihar, for their support to this survey. We thank Shri P.K. Gupta (IFS), Chief
Wildlife Warden and Additional Principal Chief Conservator of Forests-Wildlife for his support
and facilitation. We are grateful to Shri Abhay Kumar (IFS), Regional Chief Conservator of
Forests, Bhagalpur Circle, for providing us support from the Araria and Kishanganj forest
divisions, in the form of one kayak with paddles and accessories that we used in our survey.
We thank Dr. S. Kumarasamy (IFS), Conservator of Forests, Purnea, and Shri Naresh
Prashad (IFS), Divisional Forest Officer, Araria, for their support. We sincerely thank Shri
Umanath Dubey, Range Forest Officer, Kishanganj, for going out of his way to help us obtain
the kayak and related accessories in time for the survey. We are very thankful to officials
and staff of the Araria and Kishanganj forest divisions for their help, in particular Shri Rahul
Pandey, Shri Triloki Nath Jha, Shri Pankaj, and Shri Md. Jameel Akhtar.
Our second kayak along with accessories, and a tent required for the team, were
generously loaned to us thanks to Professor Sunil Kumar Choudhary (Former Head and
Professor) and Dr. C.B. Singh (Head), Department of Botany, T.M. Bhagalpur University,
Bhagalpur. We also thank Dr. Braj Nandan Kumar, Ms. Sadiya R., and Mr. Kanhaiya Kumar
Das for their support in this regard.
Our survey of the Mahananda River, the first ever such survey of the entire river in
the plains of Bihar and West Bengal, was made possible by funding support from the Wildlife
Conservation Trust and our grant donors DSP HMK Holdings Pvt. Ltd., BNP Paribas India
Foundation, and Duleep Matthai Nature Conservation Trust. We express sincere thanks to
Dr. Anish Andheria, President, WCT, for his constant support, and to Shri Atul Mukne and
Ms. Ami Gumashta for advice on budget and accounts. We thank Professor Jagdish
Krishnaswamy, Dean, School of Environment and Sustainability, Indian Institute of Human
Settlements, for his intellectual inputs to the hydrological data collection and statistical
methods used by us. A special word of thanks is essential for all the villagers of the Rupauli,
Dakra English, Raipur, Piyaji More, Kurhaila, and other villages where we spent the night
and morning during our camping by the river. In the process of interacting with the curious
and tolerant villagers, we were also able to spread awareness regarding the importance of
conserving river dolphins and other biodiversity, and made good local contacts for future
work. Last but not the least, we thank our families and friends for their constant support.

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Background to the Survey Report
The Mahananda River that flows in Bihar and West Bengal is one of the important
large tributary rivers of the Ganga, and a potentially important habitat for endangered
riverine species such as India’s National Aquatic Animal, the Ganges river dolphin. However,
the entire stretch of the river has never been surveyed so far. Approximately 250 km of the
Mahananda from Piyaji More in West Bengal to its confluence with the Ganga at Manikchak
has perennial flow. The Mahananda was first discovered to have resident Ganges river
dolphins, when the upper 45 km were surveyed by Subhasis Dey and team from T.M.
Bhagalpur University, with support from the Bihar Forest Department in April 2019. This
team recorded 14 river dolphins in this part
1
.
Following this initial report and subsequently with the Covid-19 pandemic, the
Mahananda remained the only major river in India’s range of Ganges river dolphins, where
their population was never surveyed. To address this important knowledge gap, our team at
WCT planned a complete survey of the Mahananda in November 2021 by kayak. This report
presents the first ever population estimate of Ganges river dolphins for the Mahananda. It
also updates the total population estimate for the state of Bihar and for India as well, making
it a critical contribution to the ongoing IUCN Red List Assessment of Ganges river dolphins.
It also marks the first baseline documentation of biodiversity, fisheries, and human use of the
river, which will help in future surveys, biodiversity assessments, and conservation planning.
Objectives
1. To conduct a population estimation survey of Ganges river dolphins and document
other biodiversity in the Mahananda River (250 km).
2. To generate baseline data on hydrological conditions (river flow) in the post-monsoon
dry-season.
3. To identify and enlist the impacts of human activities on river dolphins and other
biodiversity in the Mahananda, with a focus on riverine capture fisheries.
Study Area
The Mahananda River is a perennial river originating from Mahaldiram in the
Darjeeling Himalaya. Its flow is formed from two channels named the Mahananda: the main
stream from Darjeeling in Northern West Bengal and another stream entering India from
Nepal. The river enters the plains at Siliguri (West Bengal), where a barrage has been
constructed to receive water from the Teesta through the Teesta-Mahananda link canal,
1
A news report of this survey can be found here: https://www.downtoearth.org.in/news/wildlife-
biodiversity/gangetic-dolphins-found-in-bihar-s-mahananda-river-65413.

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after which other canals further withdraw water to irrigate the plains of Kishanganj, Purnea,
Katihar, Malda, and Uttar Dinajpur districts of Bihar and West Bengal. Downstream of the
barrage, the Mahananda flows along the India-Bangladesh border for a few kilometres
before entering India again near Haptia Gachh in Darjeeling district of West Bengal.
Major tributaries of the Mahananda are the Balason, Mechi, East and West Kankai,
and Parman from the west, and the Dauk (Donk) from the east. Annual rainfall in the region
is around 1400 mm and the peak monsoonal flooding season is from July to October, which
receives over 80% of the annual precipitation
2
. The dry-season begins in November and
ends by April, by which time the river flow recieves contributions from snowmelt and pre-
monsoon rainfall (Rana 2018).
In the plains, the Mahananda bifurcates and its distributary channel runs from India
into Bangladesh, where it joins the Padma (Ganges) river at Godagirighat. The main channel
that flows within India joins the Ganga near Manikchak in Malda district, West Bengal. Nearly
75% of the annual flow or runoff of the river flows in this main channel, which is sometimes
referred to as the Fulahar river (NRSC 2020). The flow of the Mahananda main stem in India
is characterized by meandering and braiding channels, with highly dynamic channel course
changes caused by flooding and related sediment erosion-deposition processes (Momin et
al. 2020). The Barind plains tract, a region of older alluvium between the Kosi megafan and
the Mahananda floodplain, is thought to be a region of highly fertile soils (Rana 2018).
Figure 1. The location of Mahananda river and major tributaries in the lower Gangetic plains. Base
map source: Global Surface Water Explorer data
3
, Pekel et al. 2016.
2
https://indiawris.gov.in/wiki/doku.php?id=mahananda_basin
3
https://global-surface-water.appspot.com/

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The people of the Mahananda plains are mainly dependent on agriculture, fisheries,
local construction works, and are involved in small agri-businesses. Several villagers work
as migrant labourers or workers in far-flung urban areas. As per the districts the river flows
through, the dominant languages spoken are Hindi, Surjapuri (a dialect of Bengali/Maithili),
and Bangla. We carried out our interactions mainly in Hindi and Bangla with local informants.
Field Schedule
We covered a river distance of 250 km in ten (10) days by two kayaks (Table 1).
Table 1. A day-wise breakup of the km distance travelled by our two kayak teams on the
Mahananda River.
Date
Day
River segment covered
River distance
(km)
16 Nov
1
Piyajimore* to Taiyabpur*
26
17 Nov
2
Taiyabpur to Raipur*
23
18 Nov
3
Raipur to Maujabari bridge
21
19 Nov
4
Maujabari bridge to Ganphaliya*
26
20 Nov
5
Ganphaliya to Rupauli*
28
21 Nov
6
Rupauli to Kurhaila*
22
22 Nov
7
Kurhaila to Durgapur
32
23 Nov
8
Durgapur to Dakra English*
22
24 Nov
9
Dakra English to Narkatti bridge*
24
25 Nov
10
Narkatti bridge to Ganga
confluence
26
2021
Total 250 km
*Night camping locations.
One of our night camping locations near Raipur, Kishanganj district, Bihar. Photo: Soumen Bakshi.

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Methodology
Our methods were focused on 1) Ganges river dolphin population estimation surveys, 2)
documentation of other biodiversity seen in the river-floodplain area, 3) estimation of river
flow (discharge) at selected reference sites, 4) documentation of human activities and fishing
practices to assess their potential impacts on biodiversity along the Mahananda river.
1. Ganges river dolphin population estimation surveys
We used the tandem-boat method to count Ganges river dolphins, based on the
principle described by Braulik et al. (2012) for Indus dolphins. This method is also alluded to
in the Field Manual prepared by Wildlife Institute of India (Qureshi et al. 2021) for Ganges
dolphin surveys. Due to the generally shallow conditions of the river, we chose to survey
river dolphins from two kayaks navigated with paddle-oars. Each kayak had two observers,
one in the front and one in the rear, with the rear observer handling the main steering and
navigation, and the front observer recording data. Kayaks allowed us great flexibility in terms
of negotiating shoals along the river channel. The two kayak teams looked for dolphins
independently by maintaining a distance of 500 m to 1 km from each other. For any
communication regarding difficulties during surveys and maintaining regular distance, paired
license-free walkie-talkie sets were used. Team recorders did not share any information on
dolphin sightings with each other, thus leading to “independence” of teams in the repeated
survey design implemented. As a result, every km of the river was surveyed twice on each
day, once by each team. This method of repeated detections “in tandem” helped assess the
uncertainty involved in detecting all animals present at a site. This was especially important
because the kayak observer height was about 0.8 m from the water surface, which meant
that detectability of river dolphins would rapidly drop with increasing distance from the kayak,
likely in very wide channels (> 500 m). For each dolphin sighting, care was taken to record
exact group sizes. In case of more than one dolphin, simultaneous surfacings of individuals
ensured that the teams did not double-count dolphins that surfaced again. For non-
simultaneous sightings very close to each other, we maintained a cut-off time of 2 seconds,
and only dolphins seen surfacing within this tiny interval were recorded as different
individuals. Size-classes of observed dolphins were recorded as “adult”, “sub-adult”, or “calf”,
depending on their apparent length and surfacing, which in adults exposed a greater length
between the blowhole and dorsal hump (Smith & Reeves 2000, Choudhary et al. 2012). We
recorded radial distance and angles from the kayak, for clearly separate individuals. We
recorded geographic coordinates, sighting time, and odometer reading of each sighting in
Garmin etrex GPS sets carried by each team, of which the coordinates and odometer
readings were used as information to match unique and common sightings between the two

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teams. The assumption made to assign common ”matches” and unique sightings was that
the relative position of dolphins in the river channel, when they were detected by the first
team, would not change for the second team, following at a distance of 500 m to 1 km. The
average kayak speeds ranged between 6 and 7 kph, which meant that the two kayak teams
were separated only by a time of about 10 minutes of rowing. Such a short interval was
unlikely to cause responsive evasive movement or other violations of the above assumption
about relative positions of dolphins. For areas where larger groups were seen, we used a
buffer of 300 m radius around each individual dolphin’s first-sight location, and any re-
sightings by the second team in this circular area were assigned as “matching”.
Survey Conditions
All surveys from 16th to 25th November were conducted in excellent weather
conditions. Apart from minor afternoon glare or light wind (state of 1) on some days and light
fog on the first hour of day 9 of the survey, sighting conditions were uniformly clear and
allowed for unambiguous long-distance detection in a window of at least 500 m. As the river
channel width mostly ranged between 150 and 400 m, this detection distance range was
more than adequate to maximize detections of surfacing dolphins.
Each day would start with a discussion between the kayak teams about distance to be covered, the
speed to be maintained, and the manner of information exchange. Photo: Soumen Bakshi.
Assessing detection bias and availability bias
Ganges river dolphins in shallow rivers often show quiescent surfacing as compared
to those in deeper channels, as per the field observations of many surveyors including
ourselves. The same was true for the Mahananda river. Dolphin surfacing patterns and
behaviours near the kayak appeared to be indifferent. To calculate detection bias, we

10
investigated differences in encounter-rates during weather conditions of wind, glare, or fog
that occasionally deviated from the generally clear conditions. Kayak height was a constraint
in accurate group size detection in general. This constraint was overcome by checking
matching counts of group size made by the two teams at their most conservative. We found
that our mean effective strip width of sighting individuals was in the region of 200-300 m,
which was thought to be rather adequate given the narrow channels of the Mahananda.
Detection probabilities were estimated directly from the double-observer analysis of our
survey data, which used, for our present purpose, a Chapman’s bias-corrected form of a
simple two-sample mark-resight estimator (Chao & Huggins 2010).
Due to the use of kayaks, boat speeds barely exceeded 7 kph. For this speed, and
based on the general estimate of about 4 minutes used as average re-surfacing time of
diving dolphins, we estimated a maximum availability bias of about 2% for a sighting window
of 200 m, based on the model of Sucunza et al. (2018).
2. Surveys of other biodiversity
Avifaunal diversity seen during the dolphin surveys was opportunistically recorded and
species-wise counts were made, with the corresponding GPS coordinates throughout the
surveyed area. In each km of river surveyed, banks and mid-channel islands were checked
once or twice with 8 x 42 binoculars to look for the presence of basking reptiles, mainly
turtles, mugger crocodiles, gharials, and otters. Similarly, banks were scanned occasionally
in locations wher sand levees were thought to have otter holts, seen as depressions carved
out in the upper portions of eroded river banks. Wherever possible, we also showed
photographs of the above species to local villagers and informants to record any reports of
sightings they may have witnessed or heard of.
Surveys were only conducted on clear weather days with excellent sighting conditions. Photo:
Soumen Bakshi.

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3. River flow studies
We assessed two main aspects of river flow conditions, as follows: 1) we estimated dry-
season river discharge at selected reference sites, by using the Manning’s equation, and 2)
we compiled and analysed available data from the Flood Management Information System,
Government of Bihar (www.fmis.bih.nic.in) to assess patterns and trends in flooding from
2013 to 2021. The Central Water Commission, Government of India, maintains gauging
stations at Taiyabpur, Maujabari, Dhengraghat, Jhawa (Jhaua) bridge, and Teljana, to
regularly record any of water level or stage, discharge, sediment concentration, and water
quality variables. However, these data being “classified” for the dry-season, are usable only
by government institutions with special permission. So, we decided to conduct direct
measurements of river cross-section depths at eight selected reference sites to estimate
discharge using the Manning’s equation (see Dey et al. 2019 for details on its application).
We obtained the river slope for the reference sites from SRTM
4
Digital Elevation Models
(DEMs) and alluvial roughness coefficients were estimated from lookup tables (Arcement &
Schneider 1984). In addition to cross-section data, data on river depth, flow velocity, channel
width, geomorphology, and habitat features were collected at regular intervals in our
surveys. The mapping of river depth along the thalweg and other shallow areas, along with
cross-section depth data, allowed us to describe the channel flow profile of the river from
upstream to downstream. River channel width was recorded from one bank to the other
using a Bushnell laser range finder.
During measurement of river depths along cross-sections, both kayak teams combined effort in data
collection. Photo: Soumen Bakshi.
4
Shuttle Radar Topography Mission.

12
4. Documentation of human activities and fishing practices
We enumerated all activities observed during our surveys along river banks and in the
river. In particular, we counted fishing and ferry-crossing boats, fishing nets and gears used,
and any indicators of fishing practices that might impact biodiversity negatively or positively.
Human use of the river floodplains for agriculture, domestic utilities, boat movement,
construction, sand mining, pollution, were systematically mapped during the survey. For this,
GPS coordinates of each human activity were recorded at the instance of approaching the
area with the said activity. For fisheries, we also asked local fishers and informants basic
details of diversity of nets, traps, and gears used, tenure or lease systems prevailing in the
area, and their understanding of impacts of fishing on river dolphins. We also asked
questions related to hunting or poaching and the use of dolphins to people, to identify their
immediate responses. We also recorded locations where boats were likely to be fishing the
catfish Clupisoma garua, using dolphin oil.
A fisher lays out his gillnet in a channel alongside a village embankment. Photo: Nachiket Kelkar.

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Results and Discussion
1. First ever Ganges river dolphin population estimate for the Mahananda
Combining all sightings from both teams, including uniques to each, we recorded a
total count of 190 Ganges river dolphins in 250 km of the Mahananda River (encounter
rate: 0.76 dolphins/km). Kayak team 1 counted a total of 138 dolphins in the river, and
team 2 counted 128, of which 76 dolphins were confirmed to be commonly sighted, through
three rounds of repeated checking of relative positional data from the GPS sets of both. Of
the 190, we recorded the size-classes of dolphins as 125 “adults”, 59 “sub-adults”, and 6
“calves”. These counts confirm a substantial and important year-round resident and
breeding population of Ganges river dolphins from the Mahananda. Our population
estimate for Ganges river dolphins was 232 ± SD 11 (95% C.I. 210-254), with an
estimated encounter-rate of 0.93 dolphins per km of the Mahananda river.
Accounting for dolphin group sizes in their localized habitat use of deep pools and
deeper channels with eroded banks and hydraulic scouring, river dolphins occurred in 94
(37.6%) of the 250 1-km segments. Over 90% of the dolphin abundance (172 of 190) was
recorded in the last 132 km of the river. Detection probabilities for the two teams were
estimated at 0.59 and 0.55 respectively. Our first Ganges river dolphin sightings came after
59 km from the starting point of the survey in Piyajimore, West Bengal. From local reports,
we estimate that the range of Ganges river dolphins, even in the monsoon season, is
unlikely to extend upstream of the Sonapur Hat river bridge.
Figure 2. Dolphin sighting locations marked as GPS points by both kayak teams. Base image:
LandSat 8 OLI TIRS Level-1 product, EarthExplorer, USGS.

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Figure 3. Villages recorded along the Mahananda in relation to dolphin hotspots (larger bubble size
indicates large group sizes in particular locations). Dolphin hotspots were mainly detected in three
areas: Maghana-Rupauli-Puranaganj (Purnia), Jhaua bridge (Katihar), Bholabari-downstream of
Narkatti bridge (Malda).

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2. Flow conditions in the Mahananda river
Using the Manning’s equation and our estimated coefficients, we calculated the average
discharge along the river to be approximately 523 m3/s (standard deviation: 326 m3/s) across
the eight reference sites in November 2021. Discharge values from upstream to downstream
showed a continued increase until the Mahananda distributary point, after which a reduction
in discharge was seen at the sites 7 and 8. The increasing discharges highlighted the
important flow contributions of tributary confluences with the Mahananda, especially the
Dauk, Mechi, Parman, and Kankai rivers. Some of the bridge sites with embankments seem
to be leading to the formation of deep pool habitats, which may be serving as refuges for
Ganges river dolphins in the peak dry-season (April-May). A quick comparison based on
satellite images from April revealed little change in river width at the bridge sites.
Figure 4. Cross-sectional profiles of eight selected reference sites along the Mahananda, upstream to
downstream (1-8). Seven of the reference sites were selected at rail or road overbridges, where river
flow is constrained by embankments so that channel width does not change except in relation to
changes in discharge. At Kurhaila, a cross-sectional profile “suitable” for use by Ganges river dolphins
is seen, with a deep area adjacent to shallower channel sites that dolphins may prefer to feed along.

16
Thalweg depths also responded to the effects of bridges and tributary confluences.
The heat map for depths shown in Figure 5 illustrates this effect. Channel depths increased
in the lower part of the river as the channel became well-defined. Maximum thalweg depths
ranged from 10-15 m at reference sites. Overall, at a few sites, depths greater than 20-25 m
were recorded near large embankment spurs constructed on the river banks to prevent
erosion and contain river flow into narrow, fast-flowing sections.
Figure 5. Ganges dolphin hotspots (circles or bubbles indicating group size) showed high overlap
with depth hotspots.

17
Ganges dolphin distribution also appeared to respond strongly to tributary confluences, as is
well known from the literature on their ecology. Dolphin sightings became increasingly
regular and less-spaced after nearly 120 km downriver (Figure 6). This pattern has been
described by Choudhary et al. (2012) for regulated tributary rivers of the Gangetic plains.
Figure 6. Occurrence of Ganges river dolphin across 1-km river segments from Piyajimore to Ganga
confluence. Most sightings are seen to occur after nearly 120 km of the starting point.
Flooding in the Mahananda: 2013-2021
The flood pulse in the Mahananda River is marked by irregular, flashy and jagged
hydrographs. These highly variable patterns probably result from the numerous tributaries of
the Mahananda, with each varying in its yearly flooding pulse and timing. In all areas where
we visited, local villagers told us that their lands were lost and houses damaged by the flood
of 2017, which was the most severe flood they had witnessed since 1987. Flood erosion and
risk to property has been a common and persisting issue for villages along the river (Young
2016). At the same time, the Mahananda is a productive fishery, maintained by flood-pulse
intensity and dynamics. We found stable trends in flood pulse peaks in general (Figure 7),
but an analysis of the variability within flood-pulses is required.
Figure 7. Time-series data on flood water levels for the Dhengraghat and Jhawa bridge sites
maintained by the Central Water Commission. Source: Flood Management Information System, Bihar.

18
Box 1. Fishing-induced river dolphin mortality in the Mahananda: a frequent occurrence?
We heard reports of river dolphin mortality from informants in many villages where we
stopped or camped overnight. The names of the villages or stops were: Taiyabpur, ghat near
Kishangank agriculture college, Ganphaliya, Rupauli, Kurhaila, Durgapur, Dakra English, and
Narkatti. Of a total ten reports of mortality, seven were attributed to entanglement in fishing nets, two
were of unknown causes, and one to the stranding of a sub-adult sized dolphin in a shallow braided
channel of the river at Marhi village.
We observed at least four boats using the method of fishing with oil-baited hook-lines. Though
we deliberately did not confirm this by asking anyone (for the sensitivities involved), we are aware that
such fishing methods are typically employed when dolphin oil is used along with offal or other flesh
bait. Areas with dolphin-oil fishing occurrence are highlighted in the map below.
The anecdotes and observations compiled from local people indicate that river dolphin bycatch is
probably not an uncommon occurrence in the Mahananda. Given that the Mahananda is heavily
fished in most areas with a diversity of nets and gears used, this may not be surprising. Impacts of
fishing-induced mortality needs to be monitored in the near future. The level of awareness regarding
the illegality of using dolphin products is likely to be low among fishers. Therefore, steps in this
direction may help greatly in reducing killing or use of dolphins. It also needs to be studied whether
the products derived from dolphins being utilized in the Mahananda are traded between fishing
groups along the Mahananda and Ganga, or even elsewhere.

19
A fisherman catching fish with hook-lines suspended from his boat. Photo: Nachiket Kelkar.
3. Other biodiversity: avifauna
A total of 123 species of birds was recorded during our survey along the river floodplain
and adjacent tracts. Due to the survey season, we were able to record most early wintering
migratory birds, which included waterfowl, waders, and some interesting raptors in passage
(see Table 2). Noteworthy records included Barheaded Goose, Mallard, Greater Scaup,
Greater Adjutant, Amur Falcon, Peregrine Falcon, Himalayan Buzzard, Longlegged Buzzard,
Pied Avocet, Northern Lapwing, Pacific Golden Plover, Lesser Coucal, and Shorteared Owl.
The most abundant species were Ruddy Shelduck, River Lapwing, Common Greenshank,
Great and Little Cormorants, common egret species, and Asian Openbill.

20
Table 2. Avifauna recorded in the Mahananda river survey.
Species name
Scientific name
Local status
Remarks and peculiar observations
Lesser Whistling-
Duck
Dendrocygna
javanica
Uncommon
Two ducks seen flying towards floodplain
wetland along river.
Greylag Goose
Anser anser
Uncommon
2
Barheaded Goose
Anser indicus
Frequent
20-25
Ruddy Shelduck
Tadorna ferruginea
Common
Abundant along the river
Cotton Pygmy-
Goose
Nettapus
coromandelianus
Uncommon
Seen in floodplain wetland along river.
Gadwall
Anas strepera
Common
Northern Pintail
Anas acuta
Uncommon
About 15 ducks seen in river
Mallard
Anas platyrhynchos
Uncommon
Redcrested
Pochard
Netta rufina
Common
5-10 ducks seen
Tufted Duck
Aythya fuligula
Uncommon
A small group seen in the river.
Greater Scaup
Aythya marila
Rare
Single bird seen among flock of Ruddy
Shelduck. ID confirmed from Tufted Duck by
larger size and greyish back.
Great Crested
Grebe
Podiceps cristatus
Common
Asian Openbill
Anastomus oscitans
Common
Nesting sites in villages along river recorded.
Abundant.
Woollynecked Stork
Ciconia episcopus
Uncommon
A few individuals recorded.
Lesser Adjutant
Leptoptilos javanicus
Uncommon
About three sightings in the lower Mahananda
only.
Greater Adjutant
Leptoptilos dubius
Rare
Solitary individual seen flying atop village near
Kishanganj. Was recorded in April as well.
Red-naped Ibis
Pseudibis papillosa
Common
Striated Heron
Butorides striata
Common
Black-crowned
Night-Heron
Nycticorax
nycticorax
Common
Indian Pond Heron
Ardeola grayii
Common
Grey Heron
Ardea cinerea
Common
Cattle Egret
Bubulcus ibis
Common
Great Egret
Casmerodius albus
Common
Intermediate Egret
Mesophoyx
intermedia
Common
Little Egret
Egretta garzetta
Common
Darter
Anhinga
melanogaster
Rare
Seen only once.
Little Cormorant
Phalacrocorax niger
Common
Great Cormorant
Phalacrocorax carbo
Common
Common Kestrel
Falco tinnunculus
Common
Abundant winter visitor seen a number of times
along the river floodplain and banks.
Lesser Kestrel
Falco naumanni
Rare
A single sighting.
Amur Falcon
Falco amurensis
Rare
A single sighting.
Peregrine Falcon
Falco peregrinus
peregrinator
Rare
A single individual recorded.
Black Kite
Milvus migrans
Common
Osprey
Pandion haliaetus
Common
Oriental Honey-
Buzzard
Pernis ptilorhynchus
Uncommon
Shikra
Accipiter badius
Common
Himalayan Buzzard
Buteo burmanicus
Rare
Three individuals seen.
Longlegged
Buzzard
Buteo rufinus
Common
Upland Buzzard
Buteo hemilasius
Rare
A single individual recorded.

21
Tawny Eagle
Aquila rapax
Common
Eurasian Coot
Fulica atra
Common
Bronzewinged
Jacana
Metopidius indicus
Common
In floodplain wetlands by the riverside.
Pied Avocet
Recurvirostra
avosetta
Uncommon
A single bird seen in a flock of greenshank.
Blackwinged Stilt
Himantopus
himantopus
Common
Seen more often in sites with sand mining.
Northern Lapwing
Vanellus vanellus
Common
Usually a rare winter visitor but commonly
encountered in sizeable flocks in the
Mahananda.
Greyheaded
Lapwing
Vanellus cinereus
Common
A mixed flock of Greyheaded and Northern
Lapwings was recorded.
River Lapwing
Vanellus duvaucelli
Common
Abundant and nesting on river islands.
Redwattled Lapwing
Vanellus indicus
Common
Pacific Golden
Plover
Pluvialis fulva
Rare
A single bird recorded.
Little Ringed Plover
Charadrius dubius
Common
Kentish Plover
Charadrius
alexandrinus
Common
Eurasian Curlew
Numenius arquata
Uncommon
A single individual.
Marsh Sandpiper
Tringa stagnatilis
Uncommom
Common Sandpiper
Actitis hypoleucos
Common
Green Sandpiper
Tringa ochropus
Common
Common
Greenshank
Tringa nebularia
Common
Highly abundant, seen in large flocks.
Little Stint
Calidris minuta
Uncommon
Small Pratincole
Glareola lactea
Common
Large flocks seen in search of floodplain
nesting sites.
Greater Painted-
Snipe
Rostratula
benghalensis
Uncommon
Pallas’Gull
Larus ichthyaetus
Uncommon
A single bird
Brownheaded Gull
Chroicocephalus
brunnicephalus
Uncommon
Four birds seen.
Blackheaded Gull
Chroicocephalus
ridibundus
Uncommon
A single bird in a flock of greenshanks.
River Tern
Sterna aurantia
Rare
A total of five birds was recorded along the
river.
Common Pigeon
Columba livia
Common
Oriental Turtledove
Streptopelia
orientalis
Common
Red Collared Dove
Streptopelia
tranquebarica
Uncommon
Eurasian Collared
Dove
Streptopelia
decaocto
Common
Spotted Dove
Stigmatopelia
chinensis
Common
Yellowfooted Green
Pigeon
Treron
phoenicopterus
Common
Recorded on a banyan tree near river camping
site
Roseringed
Parakeet
Psittacula krameri
Common
Asian Koel
Eudynamys
scolopacous
Common
Greater Coucal
Centropus sinensis
Common
Lesser Coucal
Centropus
bengalensis
Uncommon
A single sighting near Piyaji more, Darjeeling
district, where we started the survey.
Short-eared Owl
Asio flammeus
Uncommon
Six individuals seen in floodplain scrub flying
about in broad daylight.
Asian Palm Swift
Cypsiurus
Common

22
balasiensis
Common Hoopoe
Upupa epops
Common
Indian Roller
Coracias
benghalensis
Common
Whitethroated
Kingfisher
Halcyon smyrnensis
Common
Pied Kingfisher
Ceryle rudis
Common
Common Kingfisher
Alcedo atthis
Common
Lesser Goldenback
Dinopium
benghalense
Common
Small Minivet
Pericrocotus
cinnamomeus
Common
Brown Shrike
Lanius cristatus
Common
Winter visitor.
Longtailed Shrike
Lanius schach
Common
Black Drongo
Dicrurus
macrocercus
Common
Blackhooded Oriole
Oriolus xanthornus
Common
Whitethroated
Fantail
Rhipidura albicollis
Uncommon
Seen near Narkatti bridge village in bamboo
clump.
Rufous Treepie
Dendrocitta
vagabunda
Common
House Crow
Corvus splendens
Common
Plain Martin
Riparia paludicola
Common
Sand Martin
Riparia riparia
Uncommon
A single flock of 10-15, seen with Plain
Martins.
Wiretailed Swallow
Hirundo smithii
Common
Barn Swallow
Hirundo rustica
Common
Redrumped
Swallow
Cecropis daurica
Common
Bengal Bushlark
Mirafra assamica
Uncommon
Regularly encountered by the river, in sandy
and grassy open floodplain
Greater Short-toed
Lark
Calandrella
brachydactyla
Common
Sand Lark
Calandrella raytal
Uncommon
A single sighting from floodplain scrub.
Ashy-crowned
Sparrow-Lark
Eremopterix griseus
Common
Redwhiskered
Bulbul
Pycnonotus jocosus
Common
Redvented Bulbul
Pyconontus cafer
Common
Jungle Prinia
Prinia sylvatica
Common
Blyth’s Reed
Warbler
Acrocephalus
dumetorum
Common
Black Redstart
Phoenicurus
ochrurus
Common
A single sighting near Dakra English
Common Babbler
Turdoides caudata
Uncommon
A single sighting near Taiyabpur.
Jungle Babbler
Turdoides striata
Common
Jungle Myna
Acridotheres fuscus
Common
Common Myna
Acridotheres tristis
Common
Bank Myna
Acridotheres
ginginianus
Uncommon
Recorded only one nesting colony along the
river.
Asian Pied Starling
Gracupica contra
Common
Chestnut-tailed
Starling
Sturnia malabarica
Common
Oriental Magpie-
Robin
Copsychus saularis
Common
Pied Bushchat
Saxicola caprata
Common
Common Stonechat
Saxicola torquatus
Common
In floodplain scrub.
Purple Sunbird
Cinnyris asiaticus
Common

23
House Sparrow
Passer domesticus
Uncommon
Encountered in villages by the river.
Indian Silverbill
Euodice malabarica
Common
White Wagtail
Motacilla alba
Common
Yellow Wagtail
Motacilla flava
Common
White-browed
Wagtail
Motacilla
maderaspatensis
Common
Paddyfield Pipit
Anthus rufulus
Common
Olivebacked Pipit
Anthus hodgsoni
Uncommon
A single sighting.
Some bird species seen along the Mahananda River: 1) Woollynecked Stork, 2) Lesser Adjutant, 3)
Little Egret, 4) Ruddy Shelduck, 5) Northern Lapwing, and 6) Osprey. Photos: Subhasis Dey, Soumen
Bakshi, Nachiket Kelkar.
No signs or evidence of crocodiles, gharials, or otters was recorded during our surveys.
Box 2. An absence of turtles!
Our survey was marked by a particularly worrying observation, in that we did not record a single
turtle in the entire 250 km stretch that we surveyed. As our survey was in November, we expected to
see river turtles basking on the sand banks of the Mahananda. This complete absence of turtle
sightings indicated that turtles probably occurred in extremely low numbers in the Mahananda, on
account of human impacts through sand mining, hunting, and fishing. Fishers in some areas shared
with us that turtle hunting continues to a significant extent in the Mahananda. However, the dominant
factors behind the low abundance or decline of turtles still need to be carefully examined.

24
4. Impacts of human activities
The main human impacts seen on the river were intensive fishing activity with a
diversity of nets and gears, sand mining, pollution or solid waste dumping at village and
bridge sites, and construction of embankments for flood control. In general, sewage runoff
into the river, and intensive bank-side agriculture, were found to be low in intensity. Chemical
runoffs are mostly likely from sand mining and tea gardens, both concentrated in the upper
reaches, and their impacts need to be understood further, though upstream sites have
generally been identified as with poor water quality (Shil et al. 2019). At village sites,
washing, bathing, cattle-cleaning, cremation ghats, and pilgrimage ghats were common uses
of the river. With the recently concluded Chhatth festival in Bihar, a lot of organic waste was
found dumped along ghats in the places we stayed. Open defecation was also a regular
occurrence. One exception to this was the Dakra English village, where most villagers were
seen to use toilets and not river banks.
Box 3. Sand-mining in the Mahananda.
Sand and gravel or pebble mining is intensive in the upper reaches of Mahananda, upstream of
Sonapur Hat. Downstream, major mining is present only in a few locations, mostly in the Kishanganj
and Purnia districts. Contracts for substrate mining appear to be legally allotted to contractors on a
regular basis, through an e-tendering system. The map below shows numbers of sand mining clusters
along the surveyed river channels. Of the 48 clusters found, 40 were in Kishanganj district alone.

25
Fishing pressure and its impacts
The Mahananda river appears to provide a highly productive ecosystem for riverine
capture fisheries, which is observed in the intensive levels of fishing seen in and along the
river floodplains. The fishing intensity here is far greater compared to that on the Gandak
and Kosi, which are also northern perennial tributaries of the Ganga. As we have already
indicated (Box 1), fishing-induced river dolphin mortality may not be uncommon here, as a
result. The capture fisheries on the river are mainly divided into three forms of tenure and
leasing arrangements. 1. In the braided channels of the upper reaches of the Mahananda in
Kishanganj and Purnia, channels and inlets are denoted as “jalkars” and leased out to
private or cooperative bidders every year. The leased areas are usually defined to be
between two successive river bridges and are administered at the scale of block
cooperatives or police-district level purview. 2. In Katihar district, fishing is “free” under the
“Nishulk Shikarmaahi” or free fishing scheme for traditional fishers implemented on all rivers
by the Government of Bihar in September 1991 (Gazette No. 34191, No. 1906). 3. In Malda
district, fishing is directly controlled by cooperative leases granted to members of villages
residing on river banks. The differences within Bihar are interesting, and probably result from
the fact that the Mahananda becomes a single, well-defined river channel only by the time it
enters southern Purnia and Katihar districts. Accordingly, leasing systems have been
implemented differently in the upstream braided channels and the main stem downstream.
Fishing methods on the Mahananda: a) portable small gillnet, b) large gillnet deployed and drifted
from boat, c) small gillnet drifted in channel inlet, d) lift nets along river banks, e) hook-line fishing by
recreational fishers, f) push nets or dip nets used in canal from Mahananda barrage.

26
Box 4. Quotes from Francis Hamilton-Buchanan on fisheries in the Mahananda (1809-1811).
Francis Hamilton-Buchanan travelled across the erstwhile Bengal province from 1806-07 to the early
1820s. His voluminous and exceedingly detailed journal notes on the Purnia and Dinajpur regions
offer us a remarkable glimpse into the riverscape and its fisheries from the early 19th century. Here,
we cite some quotes that serve a reminder of how important – and how neglected – the Mahananda
has been.
“On the whole the lands watered by the Mahananda and its branches are by far the richest. Those
watered by the Kosi, especially towards the north and east, are rather poor and sandy.” -- page 5,
Account of the District of Purnea.
Similarly, on pages 28-38 of his Purnea Account, Hamilton-Buchanan provided a detailed description
of the Mahananda tributaries and distributaries. He also noted the large numbers of fisher families
settled along the Ganga and Mahananda in erstwhile Purnea district (including present-day
Kishanganj and parts of Katihar), and commented: “Those (fishers) on the Mahananda are much more
expert than most of the others” (p. 239-240).
Similarly, in his Dinajpur account, he mentions that “porpoises are pretty numerous in the large rivers,
but are not applied to any use” (p. 136). Ganges river dolphins were referred to as “porpoises” by
British officials back in the day. This remains, prior to our surveys, the only reference to river dolphins
occurring in the Mahananda basin rivers, to this day. The following pages (p. 137-144) describe
fishing methods in elaborate detail. One particularly notable fishing practice, also seen by Hamilton-
Buchanan (p. 138) is that of byanas, which are brushpile traps comprising branches and twigs, or
vegetation debris, placed within erected bamboo poles to attract fish, and circled by fine-sized mesh
screens. The traps of the present-day are exactly matching with the descriptions provided by
Hamilton-Buchanan nearly two hundred years ago.
A brushpile trap. Photo: Nachiket Kelkar.

27
The diversity of fishing practices in the Mahananda includes a range of nets and
gears. These include a variety of gillnets and encircling nets with variable mesh sizes, cast
nets, and mosquito nets, several kinds of basket traps and box-stake traps, fyke nets, dip or
push-nets, lift-nets, scoop-nets, brushpile traps, vegetation “fish aggregating sites”, large
barricades erected in channel inlets, and hook-line fishing. Importantly, both active and
passive methods of fishing are employed throughout the river channels, regularly. In the
lower river reaches, the intensity of trap-based fishing is staggering. In general, fishing is
more intensive in West Bengal than in Bihar. A major part of fishing is diurnal in most areas,
unlike other rivers where gillnets are often placed overnight. As we were able to survey
fisheries activity in the peak fishing season of the year (post-monsoon: November), our
documentation can be assumed to indicate the highest levels of effort possible. Fishing was
carried out not only from boats, but also by walking along shallow channels and drifting small
gillnets in shallow water areas.
Figure 8 shows the overall intensity of fishing boats and multi-purpose boats (e.g. tin
boats) to be similar, whereas motorized ferry-crossing boats seem to be higher in number
mainly downstream from southern Katihar district. In this region, we also recorded some
villages where fishing boats were motorized with large in-board engines fitted into the boat
hulls. Motorized fishing boats lead to sharp increases in fishing intensity due to the increased
efficiency and coverage possible to expand fishing effort. Figure 9 shows the differential
intensity of gillnets and cast-nets, traps, and barricade nets used in the Mahananda, which
may show the observed patterns in correlation with the tenure systems in place in different
areas. However, oil-bait fishing with hook-lines seems restricted to specific villages.
Figure 8. Relative densities (grey heatmap shades) of fishing boats, multi-purpose boats, and larger
ferry-crossing boats along the Mahananda.

28
Figure 9. Gillnets and cast nets are used almost throughout the entire river stretch, and fishing traps
dominate in the Malda district, whereas barricading mosquito-nets are mostly restricted to the section
in Katihar district. This is an interesting contrast possibly linked to leasing systems in different areas.
Conservation implications
Putting all our observations and studies together, our mapping of river depth, fishing
intensity, and Ganges river dolphin occurrences showed that dolphins mostly occurred in
deeper channels with greater fishing intensity. This observation will have important positive
and negative consequences for how Mahananda could potentially managed in the future,
keeping in mind its common importance for river dolphin conservation, biodiversity, and
fishery livelihoods. It is clear at the most basic levels that the four major districts involved are
quite different in the scope and space that they offer for future conservation interventions.
The scope is delimited not only by ecological and hydrological differences in the river
channels flowing in each section, but also with the institutional and social attributes of the
districts or different regions. Each district thus offers different opportunities and challenges.
Table 3 provides a breakup of Ganges river dolphin abundance and encounter-rates
in the river lengths (km) from our survey start point (Piyajimore) to end point (Ganga-
Mahananda confluence). This information is vital for conservation interventions and
awareness/outreach programs undertaken by the Bihar state Department of
Environment, Forests, and Climate Change at the forest division level. For instance, in
the case of Kishanganj, a decline in the number of dolphins is possible. Dey and team, in
April 2019, had surveyed 45 km of the Mahananda river within Kishanganj district (Sonapur
Hat to Dauk confluence) and found 14 dolphins. In the same stretch, we detected a total of
three dolphins. It is likely that, due to low water levels, river dolphins may have moved
downstream or that they suffered mortality due to nets or other threat factors. Future
monitoring needs to be undertaken to estimate population trends in specific river sections
under district-level forest divisions and in trans-boundary areas of West Bengal and Bihar, in
relation to hydrological change and fisheries management systems.

29
Table 3. Ganges river dolphin counts and encounter-rates divided by district and state, along the 250
km of the Mahananda River. Nearly 90% of the total counts occurred from 118 km onwards to 250
km. The highest dolphin encounter-rates were recorded in Katihar, Maldah, and Purnia districts.
River
distance (km)
Length
(km)
State
Districts
Ganges river
dolphin count
Ganges river
dolphin encounter-
rate (dolphins/km)
0-13
13
WB
Darjeeling/
Uttar
Dinajpur
0
0
13-85
72
BR
Kishanganj
4
0.055
85-91
6
WB
Uttar
Dinajpur
0
0
91-95
4
BR
Kishanganj
3
0.6
95-112
17
BR
Purnia
10
0.59
112-113
1
BR
Katihar
1
1
113-116
3
BR
Purnia
1
0.33
116-118
2
BR
Katihar
0
0
118-130
12
BR
Purnia
23
1.92
130-204
74
BR
Katihar
88
1.19
204-212
8
WB
Maldah
21
2.625
212-218
6
BR
Katihar
7
1.17
218-250
32
WB
Maldah
35
1.09
Note: Dolphins occurring exactly at the border of districts or states have been counted as belonging to
both boundary-sharing states for the purpose of this table.
Adding up the counts in Table 3, Katihar and Malda districts account for nearly 80%
of the dolphin population in the Mahananda. At the metapopulation level, the Mahananda is
a really important riverine habitat for Ganges river dolphins. With our baseline-setting
study, as far as the known range of Ganges dolphins is concerned, every single river
in India has now been surveyed at least once. The survey results bide well for the
state of Bihar, which holds the highest dolphin population for any state in India. From
its tally of about 1650 Ganges dolphins, our estimate directly takes the state tally to
around 1850 dolphins in Bihar alone!
The Mahananda river ecosystem offers a hopeful outlook for the conservation of
endangered Ganges river dolphins. Notwithstanding its significantly large dolphin population
and intensive fisheries, the Mahananda may provide scope to enhance community support
for conservation. We found, in particular, that the stretch between Rupauli and Dakra English
villages (Katihar district) may be conducive for outreach towards community-based
conservation planning. In this region, villagers were not only curious but also displayed
interest in learning about dolphins or the Susu, Sishu, Shushuk they are familiar with.

30
Whenever we would reach the destined sites to camp for the night by kayaks, little children from the
nearby villages would flock to see the boats, machines, and people that were entirely a new
experience for them. Photo: Nachiket Kelkar.
Box 5. The Mahananda and inland waterways.
The Government of India has been planning to develop waterways along most of its rivers, and the
Mahananda is also included in the list of national waterways under this. A Final Feasibility Report and
FSR of the Mahananda was also prepared by the Inland Waterways Authority of India and B.S.
Geotech Pvt. Ltd (2019). The section identified for conversion to waterways is an 80.4 km stretch of
the Mahananda distributary channel that flows through Malda and into Bangladesh. Thus, the
Mahananda stretch within India is not likely to have impacts from waterways development, which may
be a great conservation opportunity to conserve river dolphins in the Mahananda main river stem and
to protect it from any negative impacts of commercial waterway development.

31
Recommendations for future research, monitoring, and conservation
1. We recommend regular monitoring of Ganges river dolphin abundance, and studies
on seasonal changes in abundance and habitat use in the Mahananda River. The
dry-season months (March-April) will be critical to conduct seasonal assessments.
Seasonal data can help get a better sense of the overall capacity of the Mahananda
river system to support Ganges river dolphins.
2. Hydrological surveys and studies on the impacts of flow regulation are required to
ascertain the level of dependence of species on current dry-season flows. The
Mahananda, being a smaller tributary than the Gandak and Kosi, could offer us a
chance to investigate, in a space-for-time sense, the potential future effects of river
flow regulation by imminent barrages, dams, and link projects.
3. It is essential to highlight the role of the Mahananda basin tributaries, especially the
western rivers, in sustaining the overall flow of the Mahananda. The Parman river, in
particular, deserves to be studied hydrologically and surveyed once. It may not be an
overstatement to say that the Mahananda main stem river would not be the same
without its tributaries. Future water development projects being planned on the
tributaries (e.g. Kosi-Mechi link
5
) can negatively impact the flow availability for the
Mahananda main stem as well.
4. There is a need to assess the extent of dolphin mortality in fishing nets, and to check
whether extraction of oil from dolphins is practiced. This appears to be the case.
Regular monitoring of fisheries catches would be the only way forward in indirectly
estimating the levels of the above. Also, it may help to investigate if fishers on the
Mahananda are also a part of clandestine supply chains in eastern India that deal
with sale or procurement of dolphin oil.
5. Impacts of sand-mining and hunting on river turtles, in particular, needs to be studied.
6. The profile of the Mahananda as a critical habitat for Ganges river dolphins needs to
still be raised. Current conservation efforts are entirely focussed on the Ganga, and a
few of its large tributaries. Here, emphasizing on the importance of the Mahananda
will be really important.
7. Community support for river conservation needs to be harnessed especially in
localities where dolphins are commonly encountered near villages. This could be a
way to also tie in local concerns of flood erosion, embankments, livelihood security
and so on with biodiversity conservation programs.
5
http://nwda.gov.in/content/innerpage/kosi-mechi-link-project.php

32
Significance of the Survey Report
The report summarizes the main findings from the first ever thorough survey of the
Mahananda River in India, and provides the first estimate of Ganges river dolphin population
from the river at about 230 dolphins. This result is of immense significance for the imminent
“India-wide” population estimation exercises being planned by the Wildlife Institute of India
with state forest departments and other partner organizations. We have established a
baseline for the Mahananda River, which we hope will inspire further studies, monitoring
efforts, and active conservation interventions where needed, from the side of the Bihar State
Department of Environment, Forests, and Climate Change (DEFCC). The Department
expressed recent interest in developing conservation plans for all rivers of Bihar, which will
include the Mahananda, and to which our survey has already contributed. We look forward
to continued engagement with the DEFCC, Government of Bihar, to further explore and
assess with the implementation of the recommendations made in our report.
We regularly engaged ourselves in conversation with local villagers at the sites where we camped, in
order to not only do some quick awareness spreading about river dolphins and the importance of
conserving them (shown here is our campsite near the Kurhaila village). This would lead to helpful
information leads from villagers at times regarding Ganges river dolphins. Photo: Subhasis Dey.

33
Funding Support
Wildlife Conservation Trust
DSP HMK Holdings Pvt. Ltd.
BNP Paribas India Foundation
Duleep Matthai Nature Conservation Trust
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