World Journal of Fish and Marine Sciences 12 (1): 06-15, 2020 ISSN 2078-4589 © IDOSI Publications, 2020 DOI: 10.5829/idosi.wjfms.2020.06.15 Assessment of Fish Diversity in the Baleshwari River: Present Status, Threats and Conservation Perspectives 1Mst Tahira Jahan, 2,3Shaharior Hossen, 2,3Md. Rajib Sharker, 2Zahid Parvez Sukhan, 45Md. Belal Hossain, Mir Mohammad Ali and 6Md. Kyume Sharder Shadin 1Department of Aquaculture, Patuakhali Science and Technology University, Patuakhali 8602, Bangladesh 2Department of Fisheries Science, Chonnam National University, Yeosu 59626, Korea 3Department of Fisheries Biology and Genetics, Patuakhali Science and Technology University, Patuakhali 8602, Bangladesh 4Department of Fisheries and Marine Science, Noakhali Science and Technology University, Noakhali 3802, Bangladesh 5Department of Aquaculture, Sher-e-Bangla Agricultural University, Dhaka 1207, Bangladesh 6Department of Aquaculture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh Abstract: The River Baleshwari is one of the important fish reserves in southern coastal Bangladesh due to plentiful aquatic organisms especially fishes. The Greatest mangrove forest Sundarban is situated at the western side of the river. The river act as baseline of thousands of people in terms of fishing for livelihood and food. Therefore, the objectives of the present study are to list out fish diversity and conservation status of Baleshwari River. An attempt has been undertaken for duration of one year from January to December 2016 to understand the present status, diversity index and conservation status of fishes. The study revealed a total 77 fish species belonging 13 orders, 37 families and 60 genera including 11 exotic species and 5 native carps. Percifomes (32.48%) was found as dominant order followed by the nearest dominant orders was Siluriformes (22.08%), Cypriniformes (22.07%) and Clupiformes (5.20%). The findings of the study showed that Baleshwari river is the habitat of 26 threatened species (4 critically endangered, 6 endangered and 16 vulnerable as per IUCN). Calculated value of Shannon Weiner index, Gibson’s Evenness, Simpson’s dominance index, Simpson’s index of diversity and Margalef’s index of threatened species was ranges between 2.62 to 2.82, 0.55 to 0.67, 0.07 to 0.10, 0.90 to 0.93 and 2.71 to 2.77. Ranges of water quality parameter were between the favorable ranges for inhabiting the threatened fish species of which water temperature, salinity was found as major influential factors for threatened species distribution in this river. The study advocates the need to declare the Baleshwari river as a fish conservation reserve to maintain habitats for spawning, feeding and migration of threatened fish species. Key words: Fish Biodiversity Diversity Index IUCN Conservation Bangladesh INTRODUCTION location [1-4]. The southern coastal rivers of Bangladesh are categorized by high levels of commercial fish Bangladesh is a land of river which associated with catch which has direct and indirect effect to the economy a vast riverine system and for that reason the country is of the country [5-10]. The Baleshwari River is located very rich in riverine biodiversity due to geo-graphic in Bangladesh, forming part of the eastern border of Corresponding Author: Md. Rajib Sharker, Department of Fisheries Science, Chonnam National University, Yeosu 59626, Korea & Department of Fisheries Biology and Genetics, Patuakhali Science and Technology University, Patuakhali 8602, Bangladesh. E-mail: [email protected]. 6 World J. Fish & Marine Sci., 12 (1): 06-15, 2020 Bagerhat District and the western border of Barguna the study period from three selected locations namely District [11]. It borders on the east the largest mangrove Betmor Rajpara, Bara Machchua and Sapleza in Mathbaria forest in the world, in the Ganges-Brahmaputra delta, the Upazila of Pirojpur district. The locations (Figure 1) are Bangladesh part of which is set aside as the Sundarbans situated in the Mathbaria Upazila in between 22°09' and Mangrove Forest and flows south into the Haringhata 22°24' north latitudes and in between 89°52' and 90°03' River, which flows into the Bay of Bengal. Due to east longitudes (Bangladesh population census 2001). presence of Sundarban, the river comprises as a vast biodiversity including fish, shell fish, birds, mammals and Collection of Data: Primary data was collected from market other animals. In Bangladesh, there are 265 fish species visit, market survey and sample collection. Combination under 154 genera and 55 families [12]. Nowadays, fish of participatory, qualitative and quantitative data was biodiversity and management of associated habitats is a used for primary data collection. Data was collected great challenge [13, 14]. Throughout the last century, personally through face to face interviews. During this riverine ecosystems have suffered from intense human study, the PRA tool focus group discussion (FGD) was intervention resulting in habitat loss and degradation conducted with fish farmers/fishermen to get an overview and as a consequence, many fish species have become on fish distribution and marketing systems, constrains of highly endangered, particularly in rivers where heavy marketing etc. A total of 4 FGD sessions were conducted demand is placed on freshwaters [15-23]. Unimaginable where each group size was 3-4 persons and the duration evidence also indicates that increased saltwater of each session was approximately 1h. For questionnaire intrusion from the Bay of Bengal into the coastal region interviews traders, retailers, suppliers and aratdars were poses an imminent threat to coastal ecosystems and selected through simple random sampling. Information their bio-diversity [24]. As a result, a total of 64 fish about fish marketing, pricing policy, trading actions, species of Bangladesh have been declared as threatened constrains of fish marketing and socio-economic of which 9 species were recorded as critically endangered, conditions of traders are the consequences of the 30 species as endangered and the remaining 25 species interviews. Secondary data was collected by people living as vulnerable and also 27 species of fish were near the market area. assessed as near threatened by IUCN Bangladesh [25]. This situation clearly indicates the needed of detailed Sample Collection, Identification and Preservation: biodiversity study is imperative to assess the present Fish fauna collected from the study areas were status and sustainable management of water resources identified based on their morphometric and meristic in southern Bangladesh [26]. Though a very few characters following Rahman [34] and Esmeyer [35]. research works have been conducted on fish fauna in After identification, fish species were systematically different water bodies of Bangladesh [27-32] but, to the classified according to Nelson. Some fish species are best knowledge of the authors, biodiversity of tidal difficult to identify at fishing spot, however they are open waters like the Baleshwari River has not yet been preserved in 7-10% buffered formalin solution and studied. Considering the vast significance of fisheries brought to the laboratory of faculty of fisheries, resources and involvement of many fishermen in Patuakhali science and Technology University for Baleshwari River, the present study was conduct with the identification and further study. aim to explore the existing fish fauna and to formulate recommendations for effective conservation and fisheries Statistical Analysis: The collected data were analyzed by management of the river Baleshwari near eastern border of Microsoft Office Excel 2010 and then presented in textual, Bagerhat District and the western border of Barguna tabular and graphical forms to understand the present District. status of the livelihood status, threats and conservation recommendations for the fishermen and fishing MATERIALS AND METHODS community of the Baleshwari River. Study Period and Location: The study was conducted Biodiversity Parameters: In this study biodiversity, for a period of one-year from January to December 2016. evenness, richness and dominance was evaluated by the The sample and data were collected weekly throughout following formula: 7 World J. Fish & Marine Sci., 12 (1): 06-15, 2020 Fig. 1: Map of the study area Shannon-Weiner diversity index, H = - P×ii ln P [36] Simpson’s index of diversity, 1-D = 1- nii (n-1)/N (N- 1) [37]. where, Pii = n/N; n i = number of individuals of each species in the where, sample; N = total number of individuals of all species in the sample. ni = number of individuals of each species in the sample; N = total number of individuals of all species in the H Evenness,E = [26]. sample. In S S −1 where, Margalef’s richness index, d = [38] H= diversity index; S = total number of species. In N where, Simpson’s dominance index, D = nii (n-1)/N (N-1) S = total number of species, N = total number of [37]. individuals. 8 World J. Fish & Marine Sci., 12 (1): 06-15, 2020 RESULTS percent composition of families, genera and species under various orders are placed in Table 2. The dominant order According to IUCN [39], Fishes Order, Families, was Percifomes (32.48%) comprising of all the number species, English name, local name and present status in of species recorded. Nearest dominant orders were Bangladesh are mentioned in Table 1. The present study Siluriformes (22.08%), Cypriniformes (22.07%) and on fish diversity in the Baleshwari river of Bangladesh Clupiformes (5.20%). recorded a total