Consequences of climate change on fish diversity in Dekhar Haor Bangladesh

Abstract

The study has explored the implications of climate change on fish biodiversity as experienced by the local people of Dekhar Haor. It also expressed the local community's perceptions about the manifestations and consequences of climate change. In the study area, about 77.5% of people were involved with full-time fishing and 16.3% with part-time fishing. About 78.33% respondents thought that the weather has changed abruptly within the last 10 years. The study showed that the first and foremost factor is high temperature (100%). Considering biodiversity aspects, a total of 63 species under 20 families were found during the study period whereas 80 fish species under 29 families found 10 years back. The species availability status was remarked in four categories and obtained as 22 species highly available, 25 species moderately available, 16 species very low in availability and 17 species are not available. Alteration in several climatic factors like temperature, rainfall, increased drought, siltation and early flood caused overall 21.25% fish biodiversity loss where 16.67% carps, 27.27% catfishes, 10% barbs and minnows, 20% snakeheads, 20% eels, 23.08% perches, 50% featherbacks, 33.33% loaches and 16.67% miscellaneous species have been lost over a decade. Climate change in Dekhar Haor resulted in a shift to the breeding season, reduced fish biodiversity, wide variations in fish growth and taste.

Full text

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International Journal of Fisheries and Aquatic Studies 2019; 7(6): 118-124
E-ISSN: 2347-5129
P-ISSN: 2394-0506
(ICV-Poland) Impact Value: 5.62
(GIF) Impact Factor: 0.549
IJFAS 2019; 7(6): 118-124
© 2019 IJFAS
www.fisheriesjournal.com
Received: 22-09-2019
Accepted: 24-10-2019
Nirmal Chandra Roy
Professor, Department of Fish
Biology and Genetics, Sylhet
Agricultural University,
Sylhet-3100, Bangladesh
Ripon Chandra Sen
MS Student, Department of Fish
Biology and Genetics, Sylhet
Agricultural University,
Sylhet-3100, Bangladesh
Md. Atick Chowdhury
MS Student, Department of Fish
Biology and Genetics, Sylhet
Agricultural University,
Sylhet-3100, Bangladesh
Corresponding Author:
Nirmal Chandra Roy
Professor, Department of Fish
Biology and Genetics, Sylhet
Agricultural University,
Sylhet-3100, Bangladesh
Consequences of climate change on fish diversity in
Dekhar Haor Bangladesh
Nirmal Chandra Roy, Ripon Chandra Sen and Md. Atick Chowdhury
Abstract
The study has explored the implications of climate change on fish biodiversity as experienced by the
local people of Dekhar Haor. It also expressed the local community’s perceptions about the
manifestations and consequences of climate change. In the study area, about 77.5% of people were
involved with full-time fishing and 16.3% with part-time fishing. About 78.33% respondents thought that
the weather has changed abruptly within the last 10 years. The study showed that the first and foremost
factor is high temperature (100%). Considering biodiversity aspects, a total of 63 species under 20
families were found during the study period whereas 80 fish species under 29 families found 10 years
back. The species availability status was remarked in four categories and obtained as 22 species highly
available, 25 species moderately available, 16 species very low in availability and 17 species are not
available. Alteration in several climatic factors like temperature, rainfall, increased drought, siltation and
early flood caused overall 21.25% fish biodiversity loss where 16.67% carps, 27.27% catfishes, 10%
barbs and minnows, 20% snakeheads, 20% eels, 23.08% perches, 50% featherbacks, 33.33% loaches and
16.67% miscellaneous species have been lost over a decade. Climate change in Dekhar Haor resulted in a
shift to the breeding season, reduced fish biodiversity, wide variations in fish growth and taste.
Keywords: Climate change, climatic factors, fish diversity, Dekhar Haor, Haor community
1. Introduction
The vulnerability of the fisheries sector in Bangladesh is very much linked to the climate
change effects due to the dependency on the fisheries sector for her economics, diets and
socioeconomics. Climatic changes affect natural and human systems independently or in
combination with other determinants to alter the productivity, diversity, resources, functions of
ecosystems and livelihoods [1, 2]. Therefore, the effect of climate change will not only depend
on the climatic changes themselves in that area but also ecological, social and economic
factors [3]. Climate change is likely to affect adversely both the freshwater and marine fisheries
in Bangladesh. It may directly affect fishery production along with many pathways [4].
Temperature, rainfall and hydrology all affect fish reproduction, growth and migration patterns
[5, 6].
Climate change has both direct and indirect impacts on aquatic biodiversity which are
exploited commercially [7]. Brander (2007) identified that the direct effects of climate change
act on physiology, behavior, growth, reproduction, mortality and distribution and the indirect
effects alter the productivity, structure and composition of the aquatic ecosystems on which
fish depend for food and shelter [8]. Climate change stresses will have complex pressure on
fisheries and aquaculture and threatened the fish production and livelihood of the
communities. These changes have major consequences for the productivity and species
composition of fisheries resources in the region [7]. Climate change impacts gradually over a
wide range of livelihoods in different settings. Drought and siltation together are reducing
overwintering habitat for the self-recruiting fish species resulting in less recruitment in the
grazing field to grow open water inland fisheries [9]. This is limiting the livelihoods of the
thousands of the fishers who are poorest of the poor. Hossain (2015) described that, reduce
water flow in the Ganges river basin has resulted in a severe depletion of fisheries [9]. The
floodplains of the country are now among the fastest disappearing of ecological systems.
Fishing pressure from an ever-growing population has increased dramatically and has
seriously affected the abundance of inland fishes of Bangladesh, particularly small fishes like
minor carps, loaches, minnows, small catfishes, gobies, featherbacks, snakehead and eels.

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International Journal of Fisheries and Aquatic Studies http://www.fisheriesjournal.com
Haor is the important capture fisheries resource which are
large saucer-shaped floodplain depressions located mostly in
the north-eastern region of Bangladesh covering about 1.99
million ha area and accommodating about 19.37 million
people. There are about 373 Haors located in the districts of
Sunamganj, Sylhet, Maulovibazar, Habiganj, Brahmanbaria,
Netrokona and Kishoreganj, and covering an area of about
858,000 ha which is around 43% of the total area of the Haor
region [8]. Haors are unique, in terms of rich ecosystems and
biodiversity. Over the years, due to natural and manmade
causes, aquatic biodiversity especially fish diversity and other
aquatic organisms have been declining sharply. Despite the
economic importance of the Haors, people in the region are
poorer than in any other part of the country. More than 28%
of the total population here lives below the lower poverty line
(LPL) [8].
Natural disasters are the main reason for poverty, which is
aggravated by the lack of availability of basic infrastructure
and social amenities, inequity in resource acquisition and poor
access to natural resources [10]. Haor fisheries are under great
stress and their sustainability is in danger due to changing
aquatic ecosystem, siltation, unplanned construction of flood
control and drainage structure, water drainage, agro-chemical
and industrial pollutants, use of destructive fishing gears and
climate change effects [10, 11].
The climate in Bangladesh is changing and it is becoming
more unpredictable every year. The higher temperatures,
more variable precipitation, more extreme weather events,
and sea-level rise impacts are already experienced in
Bangladesh and will be intensified shortly [12]. Climate change
poses nowadays severe threat mostly in the fisheries sector
and food security among all other affected sectors. However,
climate change is likely to pose a threat to water resources
and fishery resources like Haor fisheries in Bangladesh. This
is visible in the form of temperature increase, enhanced
anomalies in the rainfall pattern and frequency and severity of
extreme events like rainfall may increase causing frequent and
devastating flash floods. A large portion of the area could face
major challenges in terms of displaced populations and their
loss of income due to climate change induced inundation. As
the agriculture and fisheries sector are the largest consumer of
water, so these sectors are highly vulnerable due to its direct
dependence on climate parameters. As a consequence of
climate change; pH change, temperature increase may affect
the fish species and also increase the occurrence of intensive
natural disasters. The main objectives of this study are to
examine the impacts that climate change poses on the Haor
resources.
2 Materials and Methods
2.1 Study area
Dekhar Haor is located in the North-East part of Bangladesh,
lies between 24°34´N to 25°12´N and 90°56´E to 91°49´E.
The Haor covers four upazilas namely Sunamganj Sadar,
Dakshin Sunamganj, Dowarabazar and Chhatak under the
Sunamganj district. The total area of the Dekhar Haor is about
11,516 hectares. Dekhar Haor wetland is made up of 36 small,
medium and large interconnecting beels (both perennial and
seasonal), canals, rivers and croplands. In monsoon, the Haor
is full of water and in the dry season, it becomes almost dry
except for some deeper beels [13]. Fishermen living in 9
villages named Joykalash, Chandrapur, Enatnagar, Parbotipur,
Raypur, Kadipur, Modonpur, Ujanigoan and Noyagaon were
selected for this study.
2.2 Data sources for the study
The study was conducted for a period of twelve months from
July 2015 to June 2016. Primary and secondary sources of
data were considered for this study. Primary data were
collected from fishermen through Face to Face (F2F)
questionnaire interviews, Focus Group Discussions (FGD)
meeting and Key Informant Interview (KIIs) were conducted
from different actors related to fisheries. The secondary
information was collected from different sources, books,
journals and thesis. A total of 160 fishermen were randomly
selected for questionnaire interviews where 4 FGDs were
made at different places of the study areas each with 12 to 20
members and 8 KIIs data was collected under this study.
Upazila Fisheries Officer (UFO), District Fishery Officer
(DFO), UP Chairman and Members, leaders of the fishermen
community, fish market leaders and school teachers were
interviewed for KIIs.
2.3 Data processing and analysis
The collected data were computed for analysis after verified
to eliminate all possible errors and inconsistencies. Data were
analyzed by using Microsoft office excels 2013 and SPSS
version 22. The tabular technique was applied for processing
the data by using simple statistical tools.
3 Results & Discussions
3.1 Fish diversity in the study areas
Haor region is naturally a fishery resourceful zone of
Bangladesh because it is rich in fish and other aquatic
biodiversity. The Haor ecosystems play a vital role in
sustaining the biodiversity of fish fauna and contribute to the
supply of animal protein and the overall economy of the
country through fish production. According to the availability
of fish species (Table 1), they were categorized into four
groups like Very low (+), Moderate (++), Higher (+++) and
Not available (NA). According to IUCN categories of fishes,
the threatened species were considered as critically
endangered (CR), endangered (EN), and vulnerable (VU) [14].
The least concerned (LC) and exotic species were also
identified (Table 1). The fish species which were found 10
years back but presently unavailable in the study areas are
presented in both Table 1 and Table 2.
Table 1: A list of different fish species as recorded during the study period
S. No.
Family
Local name
English name
Scientific name
Availability
Remarks (IUCN, 2015)
1
Cyprinidae
Catla
Indian Major Carp
Catla catla
++
LC
2
Rohu
Indian Major Carp
Labeo rohita
+++
LC
3
Mrigal
Indian Major Carp
Cirrhinus cirrhosus
+++
LC
4
Carpio
Common Carp
Cyprinus carpio
++
Exotic
5
Kalibaush
Black Rohu
Labeo calbasu
++
EN
6
Grass Carp
Grass Carp
Ctenopharyngodon idella
++
Exotic
7
Goniya
Kuria Labeo
Labeo gonius
+
EN

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8
Silver Carp
Silver Carp
Hypophthalmicthys molitrix
++
Exotic
9
Bata
Minor Carp
Labeo bata
+
EN
10
Lachu
Reba Carp
Cirrhinus reba
++
VU
11
Bagridae
Tengra
Striped Dwarf Catfish
Mystus vittatus
+++
LC
12
Bujuri
Long Bled Catfish
Mystus tengra
+++
LC
13
Golsha
Long Whiskered Catfish
Mystus cavasius
++
VU
14
Rita
Rita
Rita rita
+
CR
15
Ayre
Long Whiskered Catfish
Mystus aor
+
VU
16
Gagla
Menoda Catfish
Hemibagrus menoda
+
LC
17
Schilbeidae
Batashi
Indian Potasi
Pseudeutropius atherinoides
+
LC
18
Bacha
Batchwa Bacha
Eutropiichthys vacha
+
CR
19
Gharua
Gharua Bacha
Clupisoma garua
++
CR
20
Kajoli
Gangetic Ailia
Ailia coilia
++
LC
21
Siluridae
Pabda
Pabo Catfish
Ompok pabo
+++
EN
22
Modhu Pabda
Butter Catfish
Ompok pabda
+++
EN
23
KaniPabda
Indian Butter Catfish
Ompok bimaculatus
++
EN
24
Boal
Freshwater Shark
Wallago attu
++
LC
25
Chacidae
Chaka
Indian Chaca
Chaca chaca
NA
EN
26
Pangasidae
Pangus
Indigenous Pungus
Pangasius pangasius
NA
CR
27
Sisoridae
Gang Tengra
Clown Catfish
Gagata chenia
NA
LC
28
Baghair
Gangetic Goonch
Bagarius yarrellii
NA
CR
29
Plotosidae
Gang Magur
Canine Catfish
Plotosus canius
NA
VU
30
Olyridae
Bot Shingi
Himalayan Olyra
Olyralongic audata
NA
DD
31
Clariidae
Magur
Walking Catfish
Clarius batrachus
+++
LC
32
Heteropneustidae
Shing
Stinging Catfish
Heteropneustes fossilis
+++
LC
33
Cyprinidae
Mola
Carplet
Amblypharyngodon mola
+++
34
Dhela
Cotio
Osteobrama cotio
++
EN
35
Chela
Finescale Razorbelly Minnow
Chela phulo
++
LC
36
Darkina
Flaying Barb
Esomus danricus
+
DD
37
Tit Punti
Ticto Barb
Puntius ticto
+++
VU
38
Jat Punti
Spot Fin Swamp Barb
Puntius sophore
+++
LC
39
Teri Punti
One Spot Barb
Puntius terio
+++
LC
40
Raj Punti
Java Barb
Puntius gonionotus
++
Exotic
41
Shar Punti
Olive Barb
Puntius sarana
+
CR
42
Kosa Punti
Cosuatis Barb
Puntius cosuatis
NA
LC
43
Nanid
Nandi Labeo
Labeo nandina
NA
CR
44
Mohashol
Tor Mahseer
Tor tor
NA
CR
45
Clupeidae
Chapila
Indian River Shad
Gaduasia chapra
+
LC
46
Kachki
Ganga River Sprat
Corica soborna
++
LC
47
Channidae
Cheng
Asiatic Snakehead
Channa orientalis
+++
VU
48
Taki
Spotted Snakehead
Channa punctatus
+++
LC
49
Shol
Snakehead Murrel
Channa striatus
++
LC
50
Gozar
Giant Snakehead
Channa marulius
+
EN
51
Pipla Shol
Barca
Channa barca
NA
CR
52
Mastacembelidae
Tara Baim
One Striped Spiny Eel
Macrognathus aculeatus
+++
VU
53
Baro Baim
Two-track Spiny Eel
Mastacembelus armatus
++
EN
54
Guchi Baim
Striped Spiny Eel
Macrognathus pancalus
+++
LC
55
Sybranchidae
Cuchia
Gangetic Mud Eel
Monopterus cuchia
+
VU
56
Anguillidae
Bamosh
Indian Longfin Eel
Anguilla bengalensis
NA
VU
57
Anabantidae
Chota Khalisha
Honey Gourami
Colisa chuno
++
LC
58
Baro Khalisha
Striped Gourami
Colisa fasciatus
+++
LC
59
Lal Khalisha
Dwarf Gourami
Colisa lalia
+
LC
60
Koi
Climbing Perch
Anabas testudineus
+++
LC
61
Ambassidae
Gol Chanda
Indian Glass Fish
Parambassis ranga
+++
VU
62
Lal Chanda
Indian Glass Perchlet
Parambasis lala
+
EN
63
Lamba Chanda
Elongated Glass Perchlet
Chanda nama
++
VU
64
Cichlidae
Tilapia
Mozambique Tilapia
Oreochromis mossambicus
++
Exotic
65
Gobiidae
Bele
Bar Eyed Goby
Glossogobius giuris
++
LC
66
Nuna Bele
Bumblebee Goby
Brachygobius nunus
NA
LC
67
Nandidae
Meni
Mud Perch
Nandus nandus
+++
VU
68
Mugilidae
Khorsula
Corsula Mullet
Rhinomugil corsula
NA
LC
69
Pristolepidae
Napit Koi
Blue Perch
Badis badis
NA
EN
70
Notopteriidae
Foli
Bronze Featherback
Notopterus notopterus
++
VU
71
Chital
Humped Featherback
Notopterus chitala
NA
EN
72
Cobitidae
Gutum
Guntea Loach
Lepidocephalichthys guntea
+++
LC
73
Bou Rani
Bengal Loach
Botio dario
+
EN
74
Maitta Rani
Hora Loach
Botia dayi
NA
DD
75
Beloniidae
Kakila
Fresh Water Gar Fish
Xenentodon cancila
++
LC

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76
Hemiramphidae
Ekthute
Congaturi Halhbeak
Hyporamphus limbatus
NA
LC
77
Tetraodontidae
Potka
Ocellated Puffer fish
Tetraodon cutcutia
+
LC
78
Palaemonidae
Golda
Prawn
Macrobrachium rosenbergii
++
LC
79
Sada Icha
Prawn
Macrobrachium sp.
+++
LC
80
Kalo Icha
Monsoon River Prawn
Macrobrachium malcolmsonii
++
LC
NA: Not available; +: Very low; ++: Moderate; +++: Higher.
CR= Critically endangered; EN= Endangered; VU= Vulnerable; LC= Least concern; DD= Data deficient.
Table 2: Changes in fish availability of different group at Dekhar Haor
Name of the fish
groups
No. of available fish species 10 years
before
No. of available fish species at
present
Fish biodiversity loss over 10 years
(%)
Carps
12
10
16.67%
Catfishes
22
16
27.27%
Barbs and Minnows
10
9
10.00%
Clupeids
2
2
0.00%
Snakeheads
5
4
20.00%
Eels
5
4
20.00%
Perches
13
10
23.08%
Featherbacks
2
1
50.00%
Loaches
3
2
33.33%
Miscellaneous
6
5
16.67%
Total
80
63
21.25%
Among 63 available fish species, the highest percentage of
fishes was catfishes (25.4%) and the lowest was featherback
(1.59%). Among other groups, there were 15.87% perches,
14.29% barbs and minnows, 15.87% carps, 6.35% snakeheads
as well as eels, 3.17% loaches as well as Clupeids and 7.94%
other miscellaneous fish species (Figure 1).
Fig 1: Different types of fish groups recorded during the study
period
3.2 Impact of climate change on fisheries
3.2.1 Temperature and rainfall fluctuation of Haor
operation
Temperature and rainfall fluctuation greatly affects the fish
living and breeding condition of the Haor areas [15]. Majority
of the fish farmers, beels owners mentioned that various
problems occurred due to climate change such as over heat of
Haor and beels water, bad water quality or quality loss,
disease prevalence, insufficient water in the beels and reduce
feeding area hampered the fish growth and survival in the
open water body.
3.2.2 Delay spawning
During high temperatures, the brood fish stay at the bottom of
the waterbody to keep their body temperature in normal
condition. This condition hampers the spawning of brood fish.
During low temperature, fish body metabolism becomes slow.
Thus reducing the spawning rate.
3.2.3 Reduce body immunity
Temperature fluctuation reduces body immunity. Different
unwanted diseases may take place. As a result, fish mortality
may increase.
3.2.4 Stress of mother/brood fish
Fluctuation of temperature increase fish mobility and thus
may cause serious stress of brood fish.
3.2.5 Suffocation of brood fish
Temperature change causes loss of dissolved oxygen and
creates suffocation of brood fish. Brood fish seem to gulp at
the surface of the pond.
3.2.6 Fermentation of fish food
During high temperatures, some microorganisms may grow.
They are responsible for the fermentation of fish food. Thus,
fish nutrients may reduce in the ponds. As a result, brood
fishes face malnutrition problems. This reduces the spawning
rate.
3.2.7 Alter spawning
Brood fish requires a good spawning environment. Without
proper rainfall, the spawning rate may reduce. Even in the
artificial environment created by the hatchery operators
giving a shower of water, the spawning rate is not so high as
the natural one.
3.2.8 Elevate mortality
Improper rainfall elevates mortality. The availability of
dissolved oxygen depends greatly on proper rainfall. As a
result, the lack of rainfall causes fish mortality.
3.3 High temperature and less rainfall hampered Haor
fish
100% respondents of both non-fishermen and fishermen
perceived that temperature is increasing (Table 3).
Approximately 75% and 62.5% respondents of fishermen and
non-fishermen perceived incidents of drought have increased,
while 25% and 37.5% respondents of fishermen and non-

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fishermen perceived decrease of drought respectively. 100%
respondent of both fishermen and non-fishermen perceived
that rainfall is decreasing.
Favorable temperature and good rainfall are most important
for successfully fish breeding as well as the nursery of this
area [15]. However, high temperatures and less rain restrict fish
breeding and the nursery of Dekhar Haor. Beels owners of the
Haor areas mentioned that various factors like fish do not
ovulate, eggs not fertilized or less fertilized and lower
hatching rate occurred.
3.4 Siltation and sedimentation
Approximately 68.75% and 50% respondents of fishermen
and non-fishermen respectively perceived increased siltation
(Table 3). Due to increasing siltation in the canals and beels,
the quantity of water flow reduced and made many of the
beels much shallower, which in turn has declined the fish
production [9].
Table 3: The respondents’ perceptions of the change of climatic factors in Dekhar Haor
Perceived effects
Fishermen /Fish farmers (%)
( No. of respondent, n = 64)
Non- fishermen (%)
(No. of respondent, n = 64)
Temperature
Warmer
100%
100%
Colder
0%
0%
No change
0%
0%
Rainfall
Increased
0%
0%
Decreased
100%
100%
No change
0%
0%
Flood
Early
0%
0%
Late
87.5%
81.25%
No change
12.5%
18.75%
Drought
Increased
75%
62.5%
Decreased
25%
37.5%
Siltation
Increased
68.75%
50%
Decreased
12.5%
18.75%
No change
18.75%
31.25%
Cyclone
Frequent
0%
0%
Rare
87.5%
68.75%
Not occur
12.5%
31.25%
Wind flow
Changed
81.25%
62.5%
No change
18.75%
37.5%
3.5 Erratic or untimely flooding
Flood is one of the important climatic variables. According to
the questionnaire interviews, farmers mentioned that flood
causes disastrous problems in aquaculture. Approximately
87.5% and 81.25% respondents of fishermen and non-
fishermen perceived late arrival of floods (Table 3). Farmers
identified that fishes of Dekhar Haor suffered devastating
floods in 1974, 1987, 1988, 1998, 2004, and 2007. Floods are
becoming more frequent allegedly due to erratic rainfall
which is the outcome of climate change. Farmers stated that it
has several impacts on fish biodiversity of Haor with its grow-
out operation as well as production.
3.6 Increased intensity of cyclone and winds
Approximately 81.25% and 62.5% respondents of fishermen
and non-fishermen respectively perceived that the flow of
wind in the Haor areas is changed (Table 3). IPCC (2007)
reported that there is evidence of a 5-10% increase in intensity
(wind speed) that would contribute to enhanced storm surges
and coastal flooding and also project a 20% increase in the
intensity of associated precipitation that would contribute to
flooding [16]. Cyclone winds are likely to increase in intensity
because of the positive correlation with sea surface
temperature. In November 2007, for example, the tropical
cyclone Sidr, with a 100 miles long front covering the breadth
of the country and with winds up to 240 km per hour, hit
Bangladesh [17, 18]. This was noted to be an unusual occurrence
given the intensity and timing of the storm, particularly given
that it occurred in the same year as two recurrent floods [17].
The IPCC also noted that climate change will be associated
with greater precipitation extremes, which includes more
intense monsoonal rainfall.
3.7 Increasing drought
According to the questionnaire interviews, farmers identified
drought was one of the most important climatic variables that
have a negative impact on freshwater aquaculture.
Approximately 75% and 62.5% respondents of fishermen and
non-fishermen, respectively perceived increasing drought
(Table 3). They reported that droughts are common in Haor
and affects water supplies. Drought affects plant growth
leading to loss of primary production, food shortage and
increases fish mortality during the dry season [19]. “Rought” is
a local term used in Haor area which refers that in the winter
season mostly in Chaitro mash due to continuous sunshine the
beels of Haor suddenly dried out fully, as a result, the
fisherman catches the all of the fish from the bottom of the
beels which has negative effects on the fish diversity [19].
3.8 Climatic change reduce the fish diversity
The number of available fish species during the study period
was 63 (Table 2). Although the Haor was rich with 80 fish
species according to the questionnaire interview survey. Less
rainfall, prolonged drought and sifting season had drastically
reduced fish diversity and other organisms in open water
bodies in the study area [9, 10].
Climate changes affect the fisheries through a diversity of
direct and indirect pathways whose importance varies
depending on the type of fishery and ecosystem. During the
survey, the local personnel outlined some major causes of
lower fish diversity in the Haor area (Table 4). Based on the
overall study, some of the pathways regulating climate change
scenarios identified during this study are pointed out as
follows.

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1. Precipitation and evapotranspiration change the
hydrology of inland waters: river flows and flood timing
and extent change, affecting fish reproduction, growth
and mortality, as well as other elements of wetland-based
livelihoods (agriculture, pastorals, forestry).
2. Haor, beels including river water temperature changes the
aquatic ecology; shifting range of fish species, change in
habitat for fish species, appropriate environment for
breeding, disruption to fish reproductive patterns and
migratory routes.
3. Increased frequency of extreme events: more frequent
loss of fishing days due to bad weather, increasing loss of
nets, traps and long lines, damage to boats, increased loss
of life among fishermen, increase damage to wetland
communities.
Table 4: Major causes for diminishing local fishes outlined from the questionnaire interview
Causes
Fishers (%)
(n = 20)
Fish farmer (%)
(n = 20)
Local leader
(%) (n = 10)
School teacher
(%) (n = 10)
Housewife
(%) n = 10
Fish traders
(%) (n = 10)
Changes of climatic parameter
80
85
80
85
70
70
Lack of water around the year
65
70
65
70
60
70
Fishing through drying of beels
70
65
62
80
60
70
Chemicals use in fishing
45
45
78
75
50
60
Fishing broods
55
60
72
70
60
70
Lack of awareness
60
55
48
60
50
50
Use of current jal and kuna jal
45
40
40
50
30
60
Fishing of mother fishes
30
40
30
40
30
40
Obstacle in entering water such as
embankments, dams
20
25
15
20
20
30
Disobey the fishing act
45
55
25
30
20
30
n = No. of respondent
During the period of study, total 63 species of fish fauna
under 20 families including prawn species were available in
the study areas (Table 2). Among them, 10 species of carps,
16 species catfishes, 9 species of barbs and minnows, 2
species of clupeid, 4 species of snakeheads, 4 species of eels,
10 species of perches, 1 species of featherback, 2 species of
loaches and other miscellaneous 5 species were found
including 3 species of prawns with varying level of
availability. Bangladesh has a globally important wetland
ecosystem and associated with approximately 260 indigenous
freshwater fish species [20], but during the study period, only
63 species were found in the study areas. Therefore, fish
biodiversity is very little in comparison with the total
freshwater fish biodiversity of Bangladesh.
According to the statement of local fishermen, ten years ago
Dekhar Haor was rich with various types of fish species. At
that time, there were 80 species of fishes which included
carps (12), catfishes (22), barbs and minnows (10), clupeids
(2), snakeheads (5), eels (5), perches (13), featherbacks (2),
loaches (3) and other miscellaneous (6) (Table 2). Fishermen
were then satisfied with their everyday catch from the
wetlands.
It is revealed that there has been a gradual reduction in the
fish diversity in the Haor areas that is from the earlier
recorded 80 species to present 63 species (21.25% declined
within a decade) in the Dekhar Haor. This situation reflects
the current scenario of fishes in the open waterbodies of
Bangladesh that fish diversity is rapidly decreasing.
4. Conclusion
The study was conducted to understand the implications of
climate change on fish diversity as experienced by local
people of Dekhar Haor, Sunamganj, Bangladesh. The study
was based on a field survey method, where an appropriate
questionnaire was prepared and used for collecting data from
the villages surrounding the Haor. Most of the respondents
mentioned that flood, drought, rainfall, and temperature is
responsible for decreasing fish diversity in the Haor.
Moreover, respondents mentioned increased temperature is
also responsible for diminishing fish breeding. Besides,
seasonal changes, pollution, lack of water, habitat destruction,
fishing by completely drying and siltation are also important
causes of fish diversity degradation of the Haor area. The
study has identified that fish diversity severely affected by
climate change. Climate change is a challenge for aquaculture
in that region. Awareness training program on improved
management of environmental risk and adaptive capacity
would be very effective to conserve and enhance fish
diversity in the Haor region of Bangladesh.
5. Acknowledgement
The authors are gratefully acknowledged to the Ministry of
Science and Technology (MOST), Bangladesh for providing
financial support under Special Allocation Project for
successful implementation of this research work.
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