World Journal of Fish and Marine Sciences 7 (1): 21-28, 2015 ISSN 2078-4589 © IDOSI Publications, 2015 DOI: 10.5829/idosi.wjfms.2015.7.1.92103 Indigenous Freshwater Piscine Resources of Indian Sundarban Biosphere Reserve: Status and Prospects 1 Sourabh Kumar Dubey, 1Raman Kumar Trivedi and 2Bimal Kinkar Chand 1 Department of Aquatic Environment Management, Faculty of Fishery Sciences, West Bengal University of Animal and Fishery Sciences, 5 Budherhat Road, Kolkata-700094, India 2 Directorate of Research, Extension and Farms, West Bengal University of Animal and Fishery Sciences, Kolkata-700037, India Abstract: Study of indigenous piscine resources is utmost important because these fish species in its natural setting serves as ecological indicators. This contribution focuses on diversity and conservation aspects of freshwater indigenous fish resources of Indian Sundarban Biosphere Reserve. The study revealed the occurrence of 62 ichthyofauna belonging to 45 genera, 28 families and 9 orders. Of these fishes, 6% fish belonged to Endangered category and 2% were Vulnerable and Critically Endangered category. This article also addresses the culture potential of the small indigenous fishes as well as threat and conservation issues. Key words: Indigenous Fish Fish Diversity Sundarban Biosphere Reserve Conservation low-lying islands, of which 48 islands are occupied by human habitation in 5,363 km2 area. On the Indian side, it extends 19 community development blocks over two districts; 13 blocks in South 24 Parganas and 6 blocks in North 24 Parganas districts with total 190 Gram Panchayats and 1064 villages. The freshwater flows from the mainstream rivers and the tidal ingress from the sea result in a gradient of salinity that varies both spatially and temporally within the Biosphere Reserve. In general, the salinity is higher nearer the coast and the water in the inland side boundary of the Sundarban is nearly fresh [5]. Freshwater domains closed to blind rivers, creeks and canals in the Sundarban biosphere are about 891 km 2. The Sundarban biosphere Reserve is endowed with a vast expanse of often inland waters in the form of canals, estuaries, lakes, ponds, tanks, wetlands and paddy fields etc which always attracted attention for its cosmic aquatic recourses with rich indigenous fish diversity. Although the total estuarine habitat occupy a significant component available to fishes and play important roles as nursery and foraging grounds. The rural population, specially the rural poor, are dependent to varying degrees on these fishery resources for their livelihoods, income and food. It is well known that small indigenous fish species is significantly INTRODUCTION The inland water resources of India are renowned for their heterogeneity in fish diversity as for as their magnificent productive potential. India is the one of the mega-biodiversity countries in the world and occupies 9th position in terms of freshwater mega-biodiversity [1]. The Indian fish fauna is an assemblage of about 2500 species depicting diverse characteristics, of which 930 species belonging to 326 genera, inhabit the inland waters [2] and 1570 are found in marine water [3]. Out of these, 400 species are commercially important, which include cultured, cultivable and wild species. Globally, Indian fish represents 11% of total species, 24% of total genera and 57% of the total families [4]. The Indian Sundarban Biosphere Reserve (between 21°40'N and 22°40'N, lat. and 88°03'E and 89°07'E long.) is a UNESCO declared World heritage Site, lies on the southern fringes of the West Bengal state of India, where the Gangetic plain meets the Bay of Bengal. The Sundarban, world’s largest mangrove ecosystem, is an archipelago of several hundred islands, spread across 9,630 km2 in India and 16,370 km2 in Bangladesh. The Indian Sundarban delta comprises of 102 Corresponding Author: Sourabh Kumar Dubey, Department of Aquatic Environment Management, Faculty of Fishery Sciences, West Bengal University of Animal and Fishery Sciences, 5 Budherhat Road, Kolkata-700094, India. E-mail: sourabhkumardb@gmail.com. 21 World J. Fish & Marine Sci., 7 (1): 21-28, 2015 contributed global food security through its high quality vitamin and mineral sources [6, 7], however very less interest has been rewarded on their role in production enhancement, processing, captive breeding and conservation approaches. Subsequently in Indian Sundarban coastal biome, many indigenous fishes has become a major concern due to its constant environmental changes, over exploitation of resources, habitat destruction, pollution, demographic pressure, introduction of exotic varieties, modern agriculture etc which might be responsible for species turn over. Thus, knowledge on species and communities can reveal crucial facts necessary to the management of the ecosystems as well as to the identification of important genetic resources. Documentations on indigenous fish resources from West Bengal were carried out by several workers [8-10]. Various workers explored estuarine, marine piscine resources from water of Indian Sundarban in a scattered way [11-15]. However, detail documentations on freshwater indigenous fish resources of Indian Sundarban biosphere are really scanty. In continuation to the fact, the present works deals with an aim to explore available freshwater indigenous fish fauna from Indian Sundarban Biosphere. were associated with this survey (Paribesh Unnayan Parishad for Sagar block and Joygopalpur Gram Vikash Kendra for Basanti block). Sampling Methodology: During the survey period, fish specimens have been collected using different kinds of nets (hand net, gill net, scoop net and cast net) from almost all kinds of waterbodies like canals, beels, derelict waterbodies, ponds and road side ditches. Sampling has been conducted during early morning in between 6 to 8 AM involving the local fishermen. After collection, all the fishes captured have been immediately segregated according to their family. Those species was not identified in field, were preserved in 10% formaldehyde and brought to laboratory for further investigations. Identifications were made after following standard literatures [2, 16-18]. Conservation status of the fishes was determined according to CAMP report [19], National Bureau of Fish Genetic Resources [20] and IUCN Red list of Threatened Species [21]. Farmer’s perceptions on loss of indigenous fish diversity were noted based on cross-sectional questionnaire-based survey and focused group discussion (FGD). Threat ranks of fishes were established in 1-10 ranked hypothetical scale. RESULTS MATERIALS AND METHODS From the present short span study, total 62 ichthyofauna belonging to 45 genera, 28 families and 9 orders have been recorded from the two blocks of Indian Sundarban Biosphere Reserve (Table 1). Order perciformes represented maximum number of species distribution followed by siluriformes, cypriniformes and synbranchiformes (Figure 1). Family wise species heterogeneity was conspicuous and cyprinidae family demonstrated maximum number of individuals (13 species) followed by bagridae (6 species), channidae and gobidae (5 species each). Family siluridae, mastacembelidae and osphronemidae represented 3 individuals respectively. Likewise family ambassidae, notopteridae and tetraodontidae represented 2 individuals respectively, whereas 18 families were found to share only 1 individual species (Figure 2). It is noted that out of 62 numbers of species, 17 fish species (family bagridae, gobidae, tetraodontidae, eleotridae, anguillidae, plotosidae, belonidae) have been encountered from both freshwater and brackish water region. The present set of data also revealed that out of 62 species, 6% indigenous fish belonged to Endangered category and 2% were Study Area: A rapid survey work has been conducted for collecting and or recording the available indigenous freshwater fish fauna in two selected deltaic blocks of Indian Sundarban Biosphere Reserve namely Basanti and Sagar block under district South 24 Parganas during the months of September to December, 2011. The largest deltaic block, Sagar Island is located in the extreme western sector of Sundarban lies between 21°53' N and 88°02' to 88°15' E. This island with an area of around 300 km² is surrounded by two rivers, Hoogly and Muriganga. Both the rivers meet Bay of Bengal on either side of the Sagar Island and are totally disconnected from mainland. Basanti is located in the eastern part of Indian Sundarban biosphere lies between 22°11'21?N and 88°40'14?E with an area of 286.03 km2. It is bounded by the Matla and Vidyadhari rivers and numerous creeks. Both islands are surrounded by century old man made embankments which possible freshwater sphere within the land masses. 20 Gram Panchayats in the 2 blocks were covered during this survey (9 Gram Panchayats in Sagar block, 11 Gram Panchayats in Basanti block) and two reputed local NGOs 22 World J. Fish & Marine Sci., 7 (1): 21-28, 2015 Table 1: Checklist of indigenous freshwater ichthyofauna of Sundarban Biosphere Reserve with their endemic status Sl Order Family and Scientific name Cypriniformes Cyprinidae Amblypharyngodon mola (Hamilton) Brachydanio rerio (Hamilton) Chela laubuca (Hamilton) Puntius conchonius (Hamilton) Puntius phutunio (Hamilton) Systomus sarana (Hamilton) Puntius sophore (Hamilton) Puntius terio (Hamilton) Esomus danricus (Hamilton) Rasbora daniconius (Hamilton) Pethia gelius (Hamilton) Pethia ticto(Hamilton) Salmostoma bacalia (Hamilton) Cobitidae Lepidocephalus guntea (Hamilton) Aplocheilidae Aplocheilus panchax (Hamilton) Belonidae Xenentodon cancila (Hamilton) Bagridae Mystus cavasius(Hamilton) Mystus gulio(Hamilton) Mystus tengara (Hamilton) Mystus vittatus (Bloch) Sperata aor (Hamilton) Sperata seenghala (Sykes) Siluridae Ompok pabda (Hamilton) Ompok bimaculatus (Bloch) Wallago attu (Schneider) Plotosidae Plotosus canius (Hamilton) Schilbeidae Ailia coila (Hamilton) Pangasidae Pangasius pangasius (Hamilton) Sisoridae Bagarius bagarius (Hamilton) Clariidae Clarias batrachus (Linnaeus) Heteropneustidae Heteropneustes fossilis (Bloch) Ophichthidae Pisodonophis boro (Hamilton) Anguillidae Anguilla bengalensis (Gray) Muraenesocidae Muraenesox cinereus (Forsskål) Mastacembelidae Mastacembelus armatus (Lecepede) Macrognathus aral (Bloch) Macrognathus panculus (Hamilton) Synbranchidae Amphipnous cuchia (Hamilton) Channidae 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Cyprinodontiformes 15 Beloniformes 16 Siluriformes 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Anguilliformes 32 33 34 Synbranchiformes 35 36 37 38 Perciformes Vernacular name 23 Mourola Anju Dankena Kunchon Punti Sar Punti Deshi Punti Teri punti Darikhana Darikhana Gili punti Tit Punti Conservation status LRlc LRnt LRlc VU LRlc VU LRnt LRnt LRlc LRlc LC LRnt LRlc Gunte LC Trichokha LC Bogo LRnt Kabasi tangra Nona Tangra Tangra Sona Tangra Aor Aor LRnt LC LC VU VU LC Pabda Pabda Boal EN NT LRnt Kan magur NE Kajri VU Pangus CR Bag mach VU Magur VU Singi VU Baim LC Sona Bam EN VU Bam/Pankal Tara bam Tora/Pankal LC LRnt LRnt Cuche LRnt World J. Fish & Marine Sci., 7 (1): 21-28, 2015 Table 1: Continue 39 Channa gachua (Hamilton) Chang VU 40 Channa marulius (Hamilton) Sal/Gajal LRnt 41 Channa orientalis (Bloch) Ulko VU 42 Channa punctata (Bloch) Lata LRnt 43 Channa striata (Bloch) Sol LRlc Pod Koi VU Nadosh /Veda LRnt Gang Bele LRnt Badidae 44 Badis badis (Hamilton) Nandidae 45 Nandus nandus (Hamilton) Gobidae 46 Boleophthalmus boddarti (Pallas) 47 Glossogobius giuris (Hamilton) NE 48 Stigmatogobius sadanundio (Hamilton) 49 Pseudapocryptes lanceolatus (Cuvier) Gule LC 50 Odontamblyopus rubicundus (Hamilton) Lal chewa NE Kalo Bele LC NE Eleotridae 51 Eleotris fusca (Forster) Ambassidae 52 Chanda nama(Hamilton) Kath Chanda NE 53 Parambassis ranga (Hamilton) Lal Chanda LC Koi VU Anabantidae 54 Anabas testudineus (Bloch) Polynemidae 55 Polynemus paradiseus (Linnaeus) Topse Osphronemidae 56 Trichogaster fasciata (Schneider) Kholse 57 Trichogaster lalius(Hamilton) Lal Kholse NE 58 Trichogaster chuna (Hamilton) Chuno Kholse NE Osteoglossiformes LRnt Notopteridae 59 Chitala chitala (Hamilton) Chitol EN 60 Notopterus notopterus (Pallas) Pholui LRnt Tetraodontiformes Tetraodontidae 61 Tetraodon cutcutia (Hamilton) Tepa LRnt 62 Tetraodon fluviatilis (Hamilton) Potka LRnt CR: Critically endangered; EN: Endangered; LC: Least Concern; LRlc: Lower risk-least concern; LRnt: Lower risk-near threatened; NE: Not Evaluated; NT: Near Threatened; VU: Vulnerable Fig 1: Order wise distribution of indigenous freshwater fishes of Sundarban Biosphere Reserve 24 World J. Fish & Marine Sci., 7 (1): 21-28, 2015 Fig 2: Family wise number of indigenous freshwater fishes of Sundarban Biosphere Reserve Fig 3: Conservation status of indigenous freshwater fishes of Sundarban Biosphere Reserve Vulnarable and Critically Endangered category. However, 37 % species belonged to Lower Risk-Near Threatened category (Figure 3). The freshwater food fishes and their fishery occupied an important portion in Sundarban Biosphere Reserve. The fishes are mostly belonged to order cypriniformes, perciformes and siluriformes. The cypriniformes includes both major and minor carps. At the time of field survey it has been observed that, the major indigenous carp species viz., Labeo rohita (Hamilton), Catla catla (Hamilton) and Cirrhinus mrigala (Hamilton) along with three exotic carps mainly Cyprinus carpio (Linnaeus), Ctenopharyngodon idella, (Valenciennes) and Hypophthalmichthys molitrix (Valenciennes) were widely cultured. Farmers also stocked minor carps like Labeo bata (Hamilton), Labeo calbasu (Hamilton) along with Indian major carps. Other exotic varieties like Barbodes gonionetus (Bleeker), Hypophthalmichthys nobilis (Richardson), Oreochromis mossambicus (Peters), Oreochromis niloticus (Linnaeus) were very popular. In recent years, invasive alien species like Pygocentrus nattereri (Kner), Clarius gariepinus (Burchell) were introduced in Sundarban region and cultured in freshwater pond along with other fish. During the study period, it has been observed that freshwater indigenous carps also cultured and grew nicely in slight brackish water (> 10 ppt salinity). Among small indigenous fishes, most of them are natural breeders and can easily breed during the period of monsoon and grow up with the carps. Indigenous brackish water fishes like Lates calcarifer (Bloch), Chelon (Liza) parsia (Hamilton), Chelon planiceps (Liza tade) (Valenciennes), Chelon (Liza) macrolepis (Smith), Mugil cephalus (Linnaeus), Rhinomugil corsula (Hamilton), Etroplus suratensis (Bloch), Scatophagus argus (Linnaeus), Toxotes chatareus (Hamilton), Terapon jarbua (Forsskal) etc were found abundantly in freshwater areas and few of them were widely cultured in freshwater ponds in Sundarban region. Based on survey, some small indigenous fish species are noted out, which populations are drastically reducing since last thirty years. Farmers were rated threat rank of 25 World J. Fish & Marine Sci., 7 (1): 21-28, 2015 Table 2: Threat rank of some indigenous fishes: Farmer’s perception on loss of indigenous fish diversity since last 30 years at Sagar and Basanti block of Indian Sundarban Sagar ----------------Threat Rank Name of Fish C. gachua W. attu C. batrachus, H. fossilis S. sarana O. pabda C. marulius, C.striata, C. punctata N. nandus A. bengalensis A. testudineus A. mola Name of Fish I II III IV V VI VII VIII IX X N. nandus W. attu C. marulius, C.striata, C. punctata A. testudineus C. gachua A. bengalensis C. nama C. batrachus, H. fossilis S. sarana T. fasciata each species on 1-10 ranked hypothetical scale which are listed in Table 2. According to the farmers of Sagar Island, Channa gachua was ranked first and Amblypharyngodon mola was ranked last based upon their availability status. In Basanti block, Nandus nandus was ranked first and Trichogaster fasciata was ranked last based upon their availability status. Basanti --------------Threat Rank I II III IV V VI VII VIII IX X in India, about 23% (104 species) are highly important as food and aquarium trade and provides local livelihood security [24]. However, over exploitation of bio resources, ever expanding population pressure, pollution etc is threatened Sundarban day by day. In addition to this, temperature variability, climate induced sea level rise and subsequent erosion coupled with frequent extreme weather events, increasing salinity level etc has a serious and emergent problem in Indian Sundarban over the past two decades [25]. Due to salinity intrusion in freshwater areas, many freshwater fish species are subjected to severe stress and threat due to their inability to cope up with such extreme conditions. These may have serious impacts on the distribution, feeding regimes, breeding periodicity of indigenous freshwater fish gene pool of Sundarban. Lethal effect of salinity on two small indigenous species, A. Mola and P. ticto from Indian Sundarban was already noted by Dubey et al. [26]. Invasive alien fish species has been emerging as a growing threat to biodiversity of small indigenous fishes, as some are highly carnivorous and predatory [27-28]. In this back drop, achieving sustainable utilisation of indigenous fishes, appropriate planning for conservation and management strategies are of utmost importance. Among the indigenous fishes, many species have wider potentialities as a candidate species in freshwater aquaculture domain. These are mainly A. mola, N. notopterus, C. chitala, O. pabo and Puntius group. Murrels (Channa spp.) and air breathing fishes like A. testudineus, C. batrachus and H. fossilis are becoming a candidate species for aquaculture in India and also fetching high price in domestic markets. Non-air breathing cat fishes like M. cavasius, M. vittatus, M. tengara, S. aor etc also attracted attention for culture due to their growth DISCUSSION Marine and freshwater catches are dominated by a great diversity of small species [22]. On the contrary, aquaculture is characterized by production of a limited number of large freshwater fish species. Owing food security, lowering of indigenous freshwater fish diversity is now global concern in many developing countries. In neighboring country Bangladesh, 15% of species reported to have disappeared, 20% critically endangered and the rate of disappearance increasing in recent years due to various reasons [23]. A total number of 62 indigenous fishes occurring in freshwater zones of Sundarban Biosphere Reserve were recorded from the present short span study. In earlier study, Sen [11] reported 61 finfish species, Mandal and Nandi [12] documented 141 species under 100 genera, Nandi et al. [13] reported 76 species belonging to 28 family and Bose et al. [15] reported 74 species. Recently, Basu et al. [9] reported 52 indigenous freshwater fishes from South 24 Parganas district alone. This indicates a good health of freshwater indigenous fish co-occurring in Indian Sundarban region. Noteworthy, among documented fishes from the present investigations, maximum species have ornamental value which has been already noted by various authors [9-10]. Based on the assessment of NBFGR, among 450 small indigenous fishes 26 World J. Fish & Marine Sci., 7 (1): 21-28, 2015 and market value [24]. Based on wild seed collection, some of the fishes are being cultured in small scale. For large scale propagation, proper seed production technology and scientific farming is needed to be popularized and diversified in Sundarban area. It is also noted that, successful artificial breeding of several species like A. Mola, N. notopterus, C. chitala, O. pabo, M. Vittatus, M. gulio, S. sarana, C. batrachas, A. testudineus, N. nandus were achieved [29-31]. Maintaining piscine diversity is important because fish species in its natural setting serves as ecological indicators. To conserve and augment the sustainability of indigenous fishes in Sundarban Biosphere Reserve, research and policy framework is essential for diversification of potential cultivable indigenous fishes. In situ and ex situ conservation practice is need to be developed in various pockets of Sundarban to protect the native fish gene pool. In addition to this, through creating freshwater aquatic sanctuaries (FAS) within the protected area, public awareness can be expanded. 2. 3. 4. 5. 6. 7. CONCLUSION It can be concluded that Indian Sundarban Biosphere Reserve sustains a unique and wealthy resources of freshwater indigenous ichthyofauna. 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