Cite This Article
Mia, M.R., Uddin, M.S., Alam, M.T., Pandit, D. and Mazumder, S.K. 2022. Habitat and Biodiversity Degradation of the Surma River, Bangladesh and Implications for Future Management. Journal of Bangladesh Agricultural University, 20(1): 103–115.
https://doi.org/10.5455/JBAU.133514
ISSN 1810-3030 (Print) 2408-8684 (Online)
Journal of Bangladesh Agricultural University
Journal home page:http://baures.bau.edu.bd/jbau
Research Article
Habitat and Biodiversity Degradation of the Surma River, Bangladesh and Implications for Future Management
Md. Rasel Mia1, Md. Shahab Uddin1, Md. Tariqul Alam1, Debasish Pandit2 and Sabuj Kanti Mazumder3
1Department of Aquaculture, Sylhet Agricultural University, Sylhet-3100, Bangladesh
2Department of Aquatic Resource Management, Sylhet Agricultural University, Sylhet-3100, Bangladesh
3Department of Genetics and Fish Breeding, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur-1706, Bangladesh
ARTICLE INFO
A
BSTRACTThe investigation was carried out to provide an overview of the current resources and fisheries status of the Surma River and existing fisheries management strategies, especially focusing on fish diversity and conservation. Surma River is one of the largest aquatic ecosystems of Bangladesh and support huge amount of diverse fisheries communities. A monthly fish catch survey was carried out from March to August 2017 in the three most important catchment areas of Sylhet district; namely, Kushighat, Kanishailghat and Tuker bazar. It was completed by questionnaire interviews of fishers, focus group discussions, key informant interviews, and secondary data collection. A total of 16 different types of fishing gears were identified from the study area. Among these 7 lift net, 1 dip net, 2 gill net, 2 seine net, 1 cast net, 1 push net, and 2 hook and line were identified. The highest gear efficiency (0.77±0.06 kg.gear–1.h–1.person–1) from thela jal (Push net) in August and lowest (0.167±0.03 kg.gear–1.h–1.person–1) from jimti jal (Lift net) in March were recorded. A total of 18 sampling stations identified 53 fish species under 8 orders and 21 families, including prawns.
Cyprinidae was the leading family consisting of 34% of the total fish population. The Shannon- Weaver diversity index (H’) was found uppermost (2.68) in August and lowermost (2.14) in May.
Margalef richness index (D) was found maximum (4.86) in June and minimum (1.62) in March.
Contrariwise, Pielou’s evenness index (e) was highest (0.98) in March and lowest (0.61) in May.
However, richness index varied significantly different in all the month except in July and August (P<0.05). In 2016, the annual fish production was 268.13 MT, being almost three times than observed in 2012. Several management strategies were suggested by the stakeholders, and the findings are discussed in the context of overall developments in the Surma River fisheries related to habitat and biodiversity management.
Article history Received: 26 Dec 2021 Accepted: 02 Mar 2022 Published: 31 Mar 2022 Keywords Biodiversity loss, Surma River, Fish biodiversity, Gear efficiency, Management strategies Correspondence Sabuj Kanti Mazumder
Copyright ©2022 by authors and BAURES. This work is licensed under the Creative Commons Attribution International License (CC By 4.0).
Introduction
The Surma River, a part of the Surma-Meghna River system covering the eastern parts of Bangladesh, contains at least eight million people and making it a populous river basin in Bangladesh (Alam et al., 2007).
All these people depend on the Surma River for their household, industrial and other purposes. This river system is home to a large and diverse variety of fish.
This river conserves and supports a large variety of fish species, which in turn supports commercial fishery. But gradually the number of fishes was decreasing toward threatened status and also the water quality is deteriorating day by day due to human activities and
industrial effluents, which are built up on its bank. The Surma River is found to be highly turbid in the monsoon season. Water quality investigation indicates that water of Surma River is polluting from various sources like sewage and garbage disposal (Alam et al., 2007). So, it is very upsetting for our riverine capture fisheries which reducing its overall productivity. The most alarming issue revealed that there has been gradual reduction of fish diversity in the wetlands of the area of Sylhet district (Islam et al., 2015, 2019; Talukder et al., 2021).
Biodiversity deteriorate due to over-exploitation, pollution and contamination, siltation on riverbed, lack of awareness also include lack of government initiatives and effective steps from NGOs (Uddin, 2015; Pandit et
al., 2015; Talukder et al., 2021). In recent decades, man- made threats such as upstream dam construction, over exploitation, use of illegal fishing gears, destruction of fish sanctuaries and various ecological changes have caused gradual degradation of ordinary habitats as well as decreasing aquatic diversity, a vital problem in Bangladesh (Hossain et al., 2012; Pandit et al., 2015, 2021; Islam et al., 2019; Akter et al., 2020; Barman et al., 2021; Saha et al., 2021). All these findings clearly indicate the need for detailed biodiversity study, which is essential to assess the present status and sustainable management of a body of water (Galib et al., 2009;
Imteazzaman and Galib, 2013; Islam et al., 2019).
Despite this biological and socioeconomic significance, no systematic research and/or management strategies for the Surma River have yet been implemented. This paper describes the current status of habitat and fish biodiversity in Surma River with their compositions and rational management of these resources.
Materials and Methods
The present study was conducted in Surma River at Sylhet Sadar Upazila (24°53' 30.12'' N 91° 52' 59.88'' E)
for a period of 6 (six) months from March to August, 2017 (Figure 1). Total area of the Sylhet Sadar Upazila is 323.17 sq. km. It is bounded by Companiganj, Gowainghat and Jaintiapur upazila on the north, Dakshin surma upazila on the south, Jaintiapur and Golapganj upazila on the east, Chhatak and Bishwanath upazila on the west. Three sampling stations were selected on the basis of fishing activity, location of fishermen village, market location, water depth etc.
These are Kushighat, Tuker bazar, Khanishilghat and most of these considered as fishing grounds and fish landing centers. In a month 4 times frequent field visit in each site were conducted during the study period.
Data were collected from interviews and focus group discussions (FGDs) with primary and secondary stakeholders; direct sampling; and secondary literature.
Semi structured and structured questionnaires were developed, pretested and adapted prior to the survey proper. Key issues addressed included; present status of fish biodiversity; and habitat and biodiversity degradation and their possible management strategies.
Figure 1. Map depicting the study area (Map modified by Mazumder et al., 2020).
The stakeholders
A total of 300 stakeholders including fishermen (200), aratdars (commission agents) (20), fish traders (16), housewives (20), local leaders (10), fish farmers (10), school teachers (10), crops farmer (10), Upazila Fisheries Officer (UFO) (1), Upazila Agricultural Officer (UAO) (1), Upazila Agricultural Extension Officer (UEO) (1) and District Fisheries Officer (UFO) (1) were
participated in this study. A total of 10 Focus Group Discussion (FGD) were conducted in the study area at different places (River bank, Market, Villages and boat of fishers) with 6 to 10 members each. The characteristics of the stakeholder, including the nature of any primary dependency on the river, are summarized in Table 1.
Table 1. Categorization of key stakeholder groups and their roles in study Sl.
No.
Stakeholders No. Stakeholders Role /Contribution Involvement in
Study 1 Fishers 200 Socio-economic condition and livelihood status of fishers depend on the
Surma river.
Interview and FGD†
2
Fish farmers 10 Rare fish fry, fingerling, seed and supply. Interview Carry on various government project in the Surma river.
Promote fish production.
3
UFO
1 To inspire and support fishermen to maintain sustainable fishing practice. Interview By field based survey, identify the fishers’ problems and take the possible strategies to overcome those problems.
Minimizing political interference.
Arrange various seminar to build up the practical links and supply government message.
Implement fish acts and taking part in leasing process.
Inspiring people for fish conservation and habitat restoration to increase fish production.
4 Local leaders 10 Minimize the local conflict and regulate their sub- ordinate to maintain blameless environment.
Interview 5 School teachers 10 Create awareness among the people for sustainable use of river
resources.
Interview 6 Housewives 20 Involvement in dry fish produced, net making and mending. Interview 7
Aratders
20 Accumulate fish from fishers. Interview
Selling fish to other parties.
Act as a middle man.
8
UAO
1 Monitoring the condition of standing crops and forecast production prospects.
Interview Regulate the all agricultural activities within the Upazila.
Responsible for extension services within Upazila.
9
UEO
1 Inspire farmers to adopt new and improved methods of farming. Interview To aid the farmers to make better decisions to increase agricultural
production.
To interconnect higher authority respect to any field situation and problems.
Act as an intermediaries between research and farmers.
10 Crop farmers 10 Depend on Surma River for irrigation. Interview
11 Fish traders 16 Buying fish from fishers and other sources. Interview and Participate or Capitalize in fish business. FGD
Selling fish fry/fingerling for ranching in natural waters.
Selling and promoting fish in local market.
12
DFO
1 Contribution in policy making, planning and management is expected to lead to more realistic and effective policies and plans, as well as improve their implementation.
Interview Implement fishing acts and regulating the whole fishing activities.
Influence the overall fishing process and outcome.
†FGD – focus group discussion: target-driven informal discussions with small groups (6 to 10) of people, generally with same profession or belonging to same stratum of community
Fish catch sampling
Fish sample was collected once a week from each site during the study period with each sample performed in triplicate. When possible, fish were identified, counted, weighed and then released onsite. The collected fish were recognized on the basis of the descriptions of Rahman (2005). With the aim of estimate fishing gears
efficiency, each of the gear sample or values was taken three times from the study sites. The results were triangulated against other available secondary data sources, namely, the Department of Fisheries reports;
although non-government organization reports, scientific journal articles and other published reports and materials also were consulted. In order to estimate
the inter month catch changes of the most abundance fish species, the catch co-efficient of variation was calculated using the following formula CVw=100Sm/Xm, where, Xm and Sm are the mean and standard deviation of the monthly abundance (Glen, 2022).
Abundance and fish biodiversity
In this study, fish species diversity was calculated by Shannon-Weaver index (H′) (Shannon and Weaver, 1949), species richness by Margalef index (D) (Margalef, 1968) and evenness by Pielou’s index (e) (Pielou, 1966):
H' = Sum [pi x log (pi)]
(i) Where, H' = Shannon-Weaver index, Pi = ni/N, ni = Number of individuals of a species, N = Total number of individuals
D = (S-1)/log (N)
(ii) Where, S = Total species, N = Total individuals and, (J’) = H(s)/H (max)
(iii) H(s) = The Shannon-Weaver information function, H (max.) = The theoretical maximum value for H(s) if all species in the sample were equally abundant.
Statistical analysis
Prior to the statistical analysis, all data were tested for normality and homogeneity of variance among the different groups using a Kolmogornov-Smirnov (K-S) test on residuals and Bartlett’s test for homogeneity of variance (Sokal and Rohlf, 1995). For the presentation of the analyzed data, numerous tables, pie-charts and graphical figures were used. Mean values of H', D, e and fish production were compared among the different treatments with one way ANOVA test. In cases where the ANOVA reported significant differences, a pairwise post-hoc Tukey test was used to determine specifically which groups were different (Zar, 1984). All results were expressed as means ± S.E. All statistical analyses were performed using OriginTM Version 9.0 and Minitab version 17 computer software and the significance was indicated by P-values of less than 5%.
Results and Discussion Fishing gears
Diverse fishing gears and traps were used by seasonal, subsistence and professional fishers. A total of sixteen different types of fishing gears were identified (Table 2).
All fishing nets were categorized into 6 grouped based on their mode of operation or action and catching of fish viz., lift net, dip net, gill net, seine net, cast net, and push net. Among them seven lift net, one dip net, two gill net, two seine net, one cast net, one push net and one type of hook and one type of line was recognized.
Dimensions, deployment patterns and the area covered by gears are quite variable (Table 2).
The gear efficiency (kg h–1 gear–1 person–1) of the seven most common gears that were used in Surma River was mentioned in Figure 2. There was no significant (P >
0.05) variation, however, among gear, month, and interaction between gear and month observed when all three sample sites were compared together (Table 3).
Fish diversity
A total of 53 fish species under 8 order and 21 families were identified from study area based on the local fishermen speech, direct catch assessment and market visit. List of different fish species with their order, family name, scientific name, local name, common name or English name were mentioned in Table 4. Cyprinidae was the most prominent family consisting of 18 species with 34% of the total recorded fish species. Bagridae, Schilbeidae and Mastacembelidae contributed 11%, 8%
and 6% respectively of the total documented fish species (Figure 3).
A total of 10 most abundant fish species were recognized and documented based on month-wise weight of fish species during direct catch assessment period (Figure 4) The mean number of individual per kg fish catch (Dw) and variability (CVw) of several species illustrated in Table 5 and showed significant variations among sites (P < 0.05).
Diversity index of fish species
The species diversity index (H') was not significantly different among the different months (P>0.05). The highest H' was observed in August (2.68±0.04) while the lowest was observed in May (2.14±0.23) (Figure 5a).
However, the species richness index (D) was significantly differ among the months studied (P<0.05) (Figure 5b). In case of Plelou’s evenness index, the value of March was significantly varied than the value of May (P<0.05). However, other months were not significantly differed (P>0.05) (Figure 5c).
Fish production
During the study period, different types of water body such as River, Khal, Beel, Haor were found in the study area Table 6. According to the data from Fisheries Office, fish production showed in increasing trends in the Surma River between 2012 and 2016 (Figure 6). The Surma River serves as an excellent feeding and nursing ground for many important indigenous fish species. In addition, during the late monsoon (September to October), when the flood waters recede, fishermen indiscriminately harvest fish of all sizes using non- selective gears. Other anthropological effects, including construction of roads, dams, embankments and human settlements, also obstruct migratory routes, causing other adverse effects on the aquatic ecosystems. Thus, the recruitment of migratory species in the river is
adversely affected. Non-migratory resident spawners are also affected by overexploitation and draining of
seasonal waterbodies for other purposes, contributing to the overall low abundance of many species.
Table 2. Types of fishing gears and period of operation in Surma River
Category Types of gear
Name of gear
Main habitat
type
People Operate
Length (m)
width (m)
Volume Dm Mesh size (mm)
Durability of gears
(Years)
Construction Cost (BDT)
Target species Period
Fish nets Lift net Afa/Molli jal R 2 8.23 6.86 56.43 ─ 50.8-254 5-10 1500-3000 Boal, Khalibaus, Ilish, Gania. Mirka, Ayre, Bighead, Carpio
April-Nov.
Basta/ Dora jal
R 3 6.86 4.57 112.57 4.57 12.7 4-7 10,000-
15,000
Bele, Baim, Punti, Tengra
Nov-April
Jimti Jal 1-2 5.47 5.47 58.39 ─ 5─10 1-2 10,00-2500 SIS March-Nov
Chitka/chit jal /Dharma jal
RC 1 4.57 4.57 20.90 ─ 12.7-101.6 3-8 3,500-5000 Boal, Khalibaus, Gania. Mirka and SIS
June-Sept.
Golfa Jal R 1 91.44-
274.32
5.47 1002.2 ─ 25.4-101.5 5-7 5,000-8,000 Ayre/Aor, Rita, Baghair, Khalibaus, Gagla
Nov-April
Jam jal R 8 45.72 45.72 2090.32 ─ 25.4-101.6 4-8 15,000- 20,000
Punti, Tengra, Baim, Pabda, Gagla, Ayre,
Nov-April Goaler/
boaler jal
R 1 4.572 3.6576 16.7 ─ 50.8-101.6 2-5 1,000-2,000 Boal, Sarpunti, Khalibaus, Ilish, Gania
March-April Dip net Bal/Khora Jal RC 1 14.63 14.63 214.05 ─ 6.35-12.7 5-7 6,000-10,000 Tengra,Punti,Kakila,
Gutum,Icha,Rita, Boal, Pabda, Kalibaus, Lasu, Chapila, Chela, Rani Chingri
May-Sept.
Gill net Current Jal/
Moka/ Fash jal
RBHBaC 1 27.43 0.92 25.08 ─ 6.35-12.7 1-2 1.000-15000 Chela, Chapila, Mola, Punti,Tengra
Throughout the year Rock /sotar/
Faia jal/
Chelapata jal
RBHBa 1 137.16- 274.32
1.37 282.2 ─ 50.8-254 5-8 6,000- 10G,000
Tengra, Punti, Baim, Poa, Gagla, Ayre, Kalibaus
Nov-April
Seine net
Ber jal RBHPBa ≥ 6 228.6 9.14 2090.32 ─ 0.00 5-6 80,000- 150,000
All October-
March Utar Jal R 2 7.11 9.144 1625.26 10.92 25.4-38.1 3-7 15,000-
20,000
Tengra, Punti, Baim, Kalibaus, Mirka, Boal,
March- August Cast
net
Jhaki jal RPBH 1 6.86 4.57 860.59 10.78 ≤12.7 5-10 2,500-5,000 Tengra,Chingri, Icha,Koi, Poa, Bata, Baim, Bele, Punti, Gutum,Mola, Bacha, Khalisa,Chapila,Chela, Taki, Shing, Darkina, Catla, Sarpunti,Dela
Throughout the year
Push net
Ponar jal/Thela Jal
RBH 1 1.83 1.37 2.51 ─ 0.00 3-5 250-400 Tengra, Koi, Icha,
chingri, Punti, Taki, Kachki, Guchi baim, Meni, Chanda, Mola, Dela,
Throughout the year
Hook and line
Borshi RBHPBaC 1 1.372-
13.72
─ ─ ─ 1-2 50-150 Baim, Punti, Tengra,
Buguri Tengra, Gulsa Tengra
Throughout the year Tana kachi
Borshi
R 1─2 137.16-
274.32 (Length of line)
1-1.5 (Length
of Borshi
rope)
─ ─ ─ 2-4 3,000-4,000 Baim,Boal, Rita, Gagla, Baghair, Bacha, Laria or Gaura
June-Oct.
R, river; B, beel; H, haor; P, pond; Ba, baor; C, canal; Dm, diameter
Table 3. Analysis of variance (ANOVA) of effect of gear, month, and interaction between gear and month on fish catches with seven commonly used gear in Surma River 2017
Source DF Sum of squares Mean square F-Value P-Value
Gear 2 0.423 0.2115 0.100 0.906
Month 2 12.146 6.073 2.860 0.11
Gear*Month 4 0.950 0.2376 0.110 0.975
Error 9 19.140 2.1266
0.0 0.3 0.6 0.9 1.2 1.5
Thela Jal Khora Jal Fas jal Afa Jal
Borshi Jhaki Jal
G ea r effi ci en cy ( kg .g ea r
-1.h
-1.p er so n
-1)
Gear
March April May June July August
Jimti Jal
Figure 2. Gear efficiency (kg.gear–1.h–1.person–1) of the seven most used gears in Surma River, March-August 2017. Values are mean ± S.E.
Table 4. Fish species occurrence in Surma River with their IUCN status
Order Family Scientific Name Local Name Common Name/ English
name
IUCN status
Beloniformes Belonidae Xenentodon cancila Kakila Fresh water gar fish LC
Cypriniformes
Cyprinidae Labeo calbasu Kalibaus Black rohu LC
Cyprinidae Cyprinus carpio Carpio Common carp LC
Cyprinidae Catla catla Catla Indian major carp LC
Cyprinidae Labeo rohita Rui Indian major carp LC
Cyprinidae Labeo bata Bata Minor Carp LC
Cyprinidae Cirrhinus reba Lachu Reba Carp LC
Cyprinidae Cirrhinus cirrhosis Mrigal Indian major carp NT
Cyprinidae Labeo gonius Goniya Kuria Labeo NT
Cyprinidae Hypophthalmicthys molitrix
Silver Carp Silver Carp LC
Cyprinidae Hypophthalmichthys nobilis
Bighead carp Bighead Carp DD
Cyprinidae Amblypharyngodon mola Mola Mola carplet LC
Cyprinidae Puntius ticto Tit punti Ticto barb LC
Cyprinidae Puntius sarana Sarpunti Olive barb LC
Cyprinidae Puntius sophore Jat punti/Punti Spot fin swamp barb LC
Cyprinidae Osteobrama cotio Dhela Cotio NT
Cyprinidae Chela phulo Chela Fine scale Razor belly
Minnow
VU
Cyprinidae Esomus danricus Darkina Gangeticrasbora LC
Cyprinidae Aplocheilus panchax Kanpona/
Choukkani
Top-minnows/ Blue panchax
LC
Order Family Scientific Name Local Name Common Name/ English name
IUCN status
Cobitidae Botio dario Rani Bengal loach EN
Clupeiformes
Clupeidae Gudusia chapra Chapila Indian river shad VU
Clupeidae Tenualosa ilisha Ilish The Great Ilish ,Hilsa LC
Decapoda Palaemonidae Macrobrachium rosenbergii
Golda Prawn LC
Palaemonidae Macrobrachium malcomsonii
Icha/Gura Chingri Monsoon river prawn LC
Perciformes Anabantidae Anabas testudineus Koi Climbing perch LC
Ambassidae Chanda nama Lamba chanda High fin glassy perchlet LC Cichlidae Oreochromis mossambicus Tilapia Mozambique tilapia NT Cobitidae Lepidocephalichthys
guntea
Gutum Guntea loach LC
Gobiidae Glossogobius giuris Bele Bar eyed goby LC
Channidae Channa punctatus Taki Spotted snakehead LC
Sciaenidae Otolithoides pama Poa Pama croaker/Long-
finned croaker
VU Nandidae Nandus nandus Meni/Bheda/Roina Gangetic leaffish/ottled
nandus and mud perch
NT
Siluriformes Bagridae Sperata aor Ayre/Aor Long-whiskered catfish VU
Bagridae Mystus tengra Bujuri/KaloTengra Stripped dwarf catfish LC
Bagridae Mystus vittatus Tengra Striped dwarf catfish LC
Bagridae Mystus cavasius Gulsha Tengra Long Whiskered Catfish LC
Bagridae Hemibagrus menoda Gagla Menoda Catfish LC
Bagridae Rita rita Rita Rita EN
Siluridae Wallago attu Boal Freshwater shark VU
Siluridae Ompok pabda pabda Pabdah catfish CR
Schilbeidae Pseudeutropius atherinoides
Batashi Indian Potasi EN
Schilbeidae Eutropiichthys vacha Bacha Batchwa Bacha LC
Schilbeidae Ailia coilia Kajoli Gangetic Ailia NT
Schilbeidae Clupisoma garua Garua Garua Bachcha EN
Sisoridae Bagarius yarrellii Baghair Gangetic Goonch CR
Heteropneusdae Heteropneustes fossilis Shing Stinging Catfish LC Erethistidae Erethistes pusillus Kutakanti/ kotkoti Conta catfish LC Synbranchiformes Synbranchidae Ophisternon bengalense Bamush Bengal eel VU
Synbranchidae Monopterus cuchia Kuchia Swamp eel/Mud eel VU
Mastacembelidae Mastacembelus pancalus Guchi baim Striped spiny eel LC Mastacembelidae Mastacembelus armatus Shal/Boro baim Tire-track spiny eel EN Mastacembelidae Macrognathus aculeatus Tara baim One striped spiny eel LC Osteoglossiformes Notopteridae Notopterus notopterus Foli Bronze featherback VU
*CR = critically endangered, EN = endangered, VU = vulnerable, NT = near threatened and LC = least concern, DD=Data Deficient, *Source: IUCN 2015
Notopteridae Cobitidae Clupeidae Palaemonidae Chandidae Siluridae Synbranchidae Mastacembelidae Schilbeidae Belonidae Anabantidae Cichlidae Gobiidae Sciaenidae Nandidae Sisoridae Heteropneustidae Erethistidae
Figure 3. Percentage of fish species diversity under different family documented in the Surma River.
0 1000 2000 3000 4000 5000 6000 7000
Chela
Gulsa tengra
Kalibaus
Gutum
Baim
Guchi baim
Mola
Punti
Tengra
Boal
Abundance (kg)
March April May June July August
Figure 4. Abundance of 10 most available fish species found in the study area. Values are mean ± S.E.
Table 5. Mean number of individuals per kg fish catch (Dw) and Co-efficient of variation (CVw) within month for most abundant species in Surma river
Species Dw CVw
Kushighat
Wallago attu 0.061±0.03 323.00±85.46
Mystus vittatus 7.496±4.62 287.50±28.54
Puntius ticto 7.376±6.41 345.46±45.34
Amblypharyngodon mola 3.133±2.63 487.50±98.43
Mastacembelus pancalus 2.287±1.83 775.87±157.34
Mastacembelus armatus 0.103±0.10 382.74±22.45
Lepidocephalichthys guntea 0.673±0.69 398.21±49.07
Labeo calbasu 0.281±0.48 599.43±142.45
Mystus cavasius 0.662±0.47 776.81±302.34
Chela phulo 8.212±0.78 853.65±206.76
Kanishailghat
Wallago attu 0.024±0.02 504.00±130.00
Mystus vittatus 1.915±0.69 328.00±57.23
Puntius ticto 3.203±1.25 257.80±56.78
Amblypharyngodon mola 1.011±0.85 422.00±189.67
Mastacembelus pancalus 1.31±1.05 751.89±279.45
Mastacembelus armatus 0.067±0.05 411.80±28.98
Lepidocephalichthys guntea 0.603±0.73 373.13±147.56
Labeo calbasu 0.101±0.17 647.75±167.23
Mystus cavasius 0.448±0.55 758.93±197.9
Chela phulo 3.785±1.21 1002.73±160.87
Tuker bazar
Wallago attu 0.028±0.03 389.00±145.50
Mystus vittatus 2.513±1.62 423.40±72.45
Puntius ticto 3.689±2.49 373.34±67.43
Amblypharyngodon mola 0.989±0.61 379.54±187.34
Mastacembelus pancalus 1.296±142 689.87±231.00
Mastacembelus armatus 0.035±0.013 425.86±59.52
Lepidocephalichthys guntea 0.404±0.250 370.23±106.41
Labeo calbasu 0.103±0.093 692.80±71.32
Mystus cavasius 0.295±0.220 760.92±312.30
Chela phulo 2.426±0.245 994.32±192.40
March April May June July August
0 1 2 3 4 5
a a
a a
a
Shanon-Weaver index (H)
(a)
a
Month
March April May June July August
1 2 3 4 5
Margalef ndex (D)
Month (b)
a a
b
c d
cd
March April May June July August
0.6 0.8 1.0 1.2
ab
ab ab
Pielou's index (e)
Month (c)
a
b ab
Figure 5. Box plot showing monthly indexes of fish species in Surma River, Bangladesh. The box plots indicate the lower and upper quartiles (bottom and top box lines), the median (horizontal line in the box), the minimum and maximum values (top and bottom whiskers) and the means (open squares inside the box). Different letters on top of the box designate significant differences at P < 0.05.
2012 2013 2014 2015 2016
0 50 100 150 200 250
Fi sh p ro du cti on (m t)
Year 97.16
118.75
143.67
210
268.13
Figure 6. Fish production trends in Surma River, 2012–2016.
Source: This study; Upazila Fisheries Offices (2017).
Table 6. Total fish production in different water bodies in Sylhet Sadar Upazila
Type of water body Total Area (ha) Total fish Production (MT) Production (kg.ha-1)*
Bagjur river 32.36 5.24 319.10
Changer Khal/River 227.87 36.90 363.15
Khurshi river 267.57 43.33 315.28
Barshia river 25.35 4.11 429.19
Surma river 891.85 144.42 323.30
Khal 18.9 12.5 1190.48
Beel 1110.76 1055.57 1173.47
Haor 688 365.00 705.67
Total 3262.66 1667.07 4819.64
*Calculation of per unit production: Total production is divided by area of water body in monsoon season.
Source: This study; Upazila Fisheries Offices (2017).
Water body management strategies
Although much of the damage to the habitat and biodiversity of the Surma River over recent decades is likely to be irreversible, it has been estimated that three to four times more fish production could be ensured annually if the existing water areas were brought under proper management (Figure 6). Suggestions solicited by the stakeholders most dependent on the resource in relation to habitat restoration, biodiversity conservation, as well as increased fish production, are discussed below:
Establishment of fish sanctuaries
Conservation of fish biodiversity and healthy stock will remain keys to the success in fisheries sector in the long run. For this purpose, suitable areas in the river should be declared as protected areas like as fish sanctuaries
to facilitate conservation and protection of fish diversity, and also protection of breeding, nursing, growth, habitats, etc. Sanctuary has been tested and found as a powerful tool for protection and conservation of fish stock in the haor region of Bangladesh (Khan et al., 2018).
Minimization of domestic and agro-chemical waste products and their runoff
Land based pollution involving primarily of solid wastes such as plastics, polythene, packaging materials, toxic substances and untreated industrial effluents must be prohibited from entering into the river. In the studied area, there are three channels (locally called Chara) that carry industrial disposal and residential waste into the Surma Waterway. This Chara is located in Kazi Bazar, Akhali, and Mashimpur. These water washed away the
residues of agrochemicals used in agricultural land to the Surma River.
Establishment of fish-friendly infrastructures
Dams and barrages are greatly detrimental to river ecosystems. Improvident construction of bridges, culverts, flood control embankments, etc., has interrupted the spawning, breeding and feeding migration of fish and other aquatic animals in the river ecosystems. Fish friendly structure like fish pass may be a good option for reopen migration route between river and haor or beel and consequently mitigate the loss of nursing, feeding and breeding of indigenous fishes having positive impact on fish production and biodiversity (Alam and Ahmed, 2005).
Proper implementation of existing fisheries rules and regulations
Existing government rules and regulations for open- water fisheries management are often ignored by local people and fishers in the present study area. Thus, their upgraded enforcement is urgently needed to maintain sustainable fisheries. Policy makers should think about eco-management of such common resource pool (Sunny et al., 2021)
Implementation of proper institutional arrangements and frameworks
Lack of sufficient or administrative frame works, and appropriate policies, weak implementation of present policies, lack of integration of sectoral activities are the main threat to biodiversity in Surma River. So suitable coordination and cross sectoral integration, strong national information system and adequate knowledge on structure and function are vital factor to maintain biodiversity. Understanding fishers’ livelihood through a sustainable livelihood approach is urgent to maintain healthy and friendly eco-system in the studied area (Sunny et al., 2021).
Strengthening monitoring networks
Monitoring is mainly important in understanding the fate of ecosystems, habitats and rare and endangered species. Various illegal activities perform in the Surma River due to lack of proper monitoring system. Fishers’
involvement in the management system is also important here.
Education, training and publicity
Education, training and publicity about river management help to raise awareness among fishermen, fishing associations and other relevant groups about the need for better management; and to promote implementation of rules and regulation in the river ecosystems. As a result, the level of pollution will be reduced.
Fish stock enhancement program
Stock enhancement is a management tool used to recover depleted species populations that have faced threats such as overfishing, habitat loss, or ocean acidification. Fish Stock enhancement program is urgently necessary in Surma River because standing stock of the Surma River is extremely depleted. During the study, nearby individuals and anglers said that the most profitable fish, such as rani, rita, foli, baghair, etc., are not available at this time. So an annual stock enhancement program should be undertaken to reestablish and maintain a sustainable year-round standing biomass. A number of species performed very well in floodplain stock enhancement programmes, including rui, catla, mrigal, kalibaus, silver carp, common carp and Thai sarpunti (Ali and Islam 1998).
Adjustment of selective fishing gears, mesh sizes, and fishing dewatering
Destructive fishing practices are the causes of irreversible damage to aquatic habitats and ecosystems.
Regulation of selective fishing gears and mesh sizes must be implemented. Illegal fishing, undersized fishing, indiscriminate killing of brood by illegal fishing gear, destroy fish seeds by dewatering and use of monofilament nets in any season should be strictly prohibited. The use of seine net (ber jal) and gill net (current jal) must be prohibited to enforce the fish protection and conservation act.
Use of sound dose pesticides and insecticides and inorganic fertilizers
Pesticide affects the aquatic ecosystem by interrupting the aquatic food chain of open water fish species resulting loss of natural diversity (Juthi et al., 2017;
Alam et al., 2016; Parveen and Faisal, 2003). Use of sound dose pesticides and insecticides and inorganic fertilizers will help to mitigate the loss of fish diversity in Surma River.
Proper management of industrial effluents
Local people dumping their all domestic waste in this three identified Chara and finally this waste fall into river by this channel. This unfavorable effect ultimately destroys fish diversity in the Surma River. Therefore, it is necessary for Effluent Treatment Plants to maintain the water quality of the Surma River.
Establishment of community-based organizations (CBO) Management of open water fisheries through auction can perform exactly in many open water systems. At present the Surma River system under sylhet sadar upazila divided into various parts to maintain good management practice. In this management system specific fisherman catches fish in specific area or part
that reduced the conflicts among the fisherman or fishing villagers.
Excavation of silted area of Surma River system to maintain minimum water depth during dry season The dry season is the critical time for the fishes, when water levels in the rivers are greatly reduced. Fish are exposed to greater predation and increased susceptibility to fishing pressure. The complete removal of fish by dewatering during the dry season should be banned, and a minimum of 1 m water depth should be maintained in the main basins through regulation and water transfers, where necessary (Hossain et al., 2009).
River maintenance and erosion control
Soil erosion increases the turbidity during rainy season.
So strong embankment establish can reduce the riverbank erosion. During survey it was noted that some area of Riverbank of Surma River was coved by rock block. But it is not sufficient.
Public awareness
Public awareness is a key tool for management of water quality as well as healthy water body. Every day many people dumping their waste material into the River willingly or unwillingly. Majority of the people are not conscious about the environmental impact of biodiversity loss. So awareness raising program should be adopted surrounding the River area for the conservation of the biodiversity.
Conclusion
The Surma River is one of the largest water ecosystems covering the north- eastern part of Bangladesh. It plays a major role in sustaining life forms, supporting humankind in different ways, and contributes to the total economy of the country through fish production.
Nowadays, manmade factors especially habitat destruction are the main threats to loss the fish diversity of the Surma River. Therefore, necessary steps should have to take for the protection and conservation of these valuable fisheries resources. Restriction on fishing practices during breeding season, controlled discharge of domestic wastes, proper management of industrial effluents, banning the use of illegal fishing gears during fishing, controlling overfishing, establishment of fish sanctuaries, adjustment of selective fishing gears and mesh sizes, education, training and publicity etc. can be done. Data distribution and collaboration between academic institutions and governmental agencies are particularly indispensable for the effectiveness of fish conservation.
The researchers, investigators, policymakers, government, and local NGOs, national and international bodies and people of all classes should come forward to
conserve the fish species using both in situ and ex situ approaches.
Author’s Contribution
M.R.M.: Design, formulation, field data collection, and writing of manuscript. M.S.U.: Design and supervision.
M.T.A.: Supervision and review. D.P.: Writing, editing, and review of manuscript. S.K.M.: Writing and review of manuscript.
Acknowledgements
We wish to acknowledge the Upazila Fisheries Officers (UFO), Upazila Agriculture Officers (UAO) and other stakeholders for their sincere cooperation and assistance in this research.
Competing interests
The authors have declared that no competing interests exist.
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