Academia Journal of Agricultural Research 4(2): 072-081, February 2016 DOI: 10.15413/ajar.2015.0198 ISSN: 2315-7739 ©2015 Academia Publishing Research Paper Identification of fishing technologies and their probable impacts on fish folk diversity in the Bishkhali River of Jhalakathi District in Bangladesh Accepted 12th January, 2015 ABSTRACT The Bishkhali River, situated at Jhalakathi district under Barisal division of Bangladesh has immense importance as it supports lifeline of thousands of people. Different types of gears are used in the river to harvest fish species. Therefore, an attempt was undertaken to know the existing fishing gears and their impacts on fish fauna for a period of 10 months from January, 2015 to October, 2015. Results of the study revealed that a total of 18 fishing gears belong to 7 major groups. In total, 51 species under 11 orders, 27 families and 42 genera were identified in the catches of different gears. Among the different orders, Perciformes formed the largest dominant order contributing 16 species (32%) followed by Siluriformes Rahman M B1*, Sazedul Hoque1, Mizanur having 13 species (24.49%). A total of 1,4579 individuals of fishes were caught of Rahman1 which abundant species was Corica soborna, having 1,944 individuals (13.33%). 1Department of Fisheries Technology, Out of 51 species, 16 species were identified as threatened. The species diversity Faculty of Fisheries, Patuakhali Science was analyzed using the following diversity indices: Shannon-Weiner index (H); and Technology University, Dumki, Gibson’s evenness (E); Simpson dominance index (D); Simpson index of diversity Patuakhali-8602, Bangladesh. 2Department of Fisheries Management, (1-D) and Margalef’s index. Shannon-Weiner index (H); Gibson’s evenness (E) and Faculty of Fisheries, Patuakhali Science Margalef’s index showed higher values at sampling sites S1. The ecology of the and Technology University, Dumki, Bishkhali river is in great threat due to excess fishing pressure by illegal fishing Patuakhali-8602, Bangladesh. gears, pollution and siltation. Therefore, scientific based study is prerequisite to *Corresponding author e-mail: protect the fish fauna from extinction. [email protected] Tel: +8801710450610. Key words: Bishkhali river, conservation, fish fauna, fishing gears, impacts. INTRODUCTION Bangladesh is utterly inventive with extremely rich and Fish is deliberated as one of the most significant food extensive inland, coastal and marine water resources which items from the very beginning of human civilization (Akter mainly consists of floodplains, haors, baors, beels, rivers, et al., 2012). It is one of the major important elements in estuaries, coastal belt and seashore which all together offer the aquatic habitat and plays a key role in economy of many tremendous opportunities for fisheries development and nations as they have been a stable item in the diet of many livelihood support of the people living around these inland people (Kouamelan et al., 2003). Again, Fisheries is a sub- water bodies. Along with potential water resources, sector of Agriculture, having significant role and main Bangladesh is also rich in the diversity of various fish source of animal protein, employment opportunities, food species and other important aquatic biota. Hence, it is security, foreign incomes and socio-economic improvement ranked fourth (DoF, 2015) in fish biodiversity in Asia (Siddiq et al., 2013). This sector contributes 3.69% to GDP behind China, India and Thailand, with approximately 800 and 22.76% to agricultural GDP. Fish supplements to about species of fish from fresh, brackish and marine water 60% of our daily animal protein intake (DoF, 2015) to meet (Hussain and Mazid, 2001). the country’s health demand and thereby helps to reduce Academia Journal of Agricultural Research; Rahman et al. 073 Figure 1. Geographical location of study area; (a) map of Bangladesh and (b) map of Bishkhali River with four sampling stations (S1, S2, S3 and S4 manifested as red rounded). malnutrition problem. considering government rules related to aquatic The importance of fish biodiversity is always noteworthy biodiversity and conservation. Consequently, fish fauna of which can never be negligible. But freshwater fishes of the river are under threat. As a result, recording of fishing Bangladesh are the most threatened group and therefore, gears including their mesh sizes, fish diversity and their conservation is a pre-requisite to protect the fish fauna conservation status has become a central aspect to from near extinction. To commence these conservation understand the river ecosystem and conserve the fish initiatives, basic informations of fishes like breeding fauna. The information from this investigation will serve as seasons and conservation status are essential tools. Study a baseline data for carrying out further study on ecology, of fish fauna in any water body would be of great help to conservation, sustainability and management of fisheries take appropriate conservation steps in the water body. resources of this water body. Though a very few research works have been conducted on fish fauna in different water bodies of Bangladesh (Islam et al., 2015; Galib et al., 2013; Imteazzaman et al., 2013; MATERIALS AND METHODS Mohsin et al., 2009), there is no satisfactory information found in the literature regarding fish fauna and fishing Study area and duration of research gears used to capture fish of the Bishkhali River. The Bishkhali is a coastal river under Jhalakathi district of The present investigation was imposed on Bishkhali River, Bangladesh. The river is the harbor of diversified fish fauna. located at Jhalakathi district under Barisal division of Thus, the rivers influence the life style of countless people Bangladesh. Its center lies between 21.9833°N latitude living along and near the coast of the river. At the same and 89.9833°E longitude and falls into the Bay of Bengal time, it is observed that numerous non-selective and illegal (Figure 1) through the mouth of the Baleswar-Haringhata mesh size gears are used to capture fishes without at 13 km down of Patharghata. The total length of the river Academia Journal of Agricultural Research; Rahman et al. 074 is 96 km with average depth about 16 m. To execute the Analysis of findings objectives of the existing work relevant data were collected fortnightly basis, that is, twice a month for a period of 10 For the analysis of present findings statistical analyses months from January, 2015 to October, 2015. were carried out using Microsoft Excel 2007 and Statistical Packages for Social Sciences (SPSS) version 16.00. Measurement of fishing gears RESULTS AND DISCUSSION The fishing gears were surveyed based on participatory Fishing gears rural appraisal (PRA) such as focus groups discussion (FGD), social mapping and cross checking key informant Fishing gears are equipments used to catch aquatic biota interviews (KIA) with fisher’s community fishing in the four especially fishes. For fishing, different types of fishing gears different spots of Bishkhali River. The mesh size of the and traps were employed in Bishkhali River over a period gears was estimated using a centimeter scale (CRESCENT, of time. Table 1 represents the summary of fishing gears Made in China). The fishing gears were categorized under used in Bishkhali River. From the study, a total 18 different different major groups followed by Ahmed (1971). types of fishing gears were identified under 7 major groups such as gill nets (current jal, poma jal, ayre jal,tengra jal, punti jal, ilish jal and fash jal), cast nets (jhaki jal), push nets Fish specimen collection and identification (moia jal and thela jal), seine net (ber jal), fixed purse nets (char jal and badha jal), lift nets (dharma jal, chabi jal and Fish specimens were collected from four fishing spots (S1, ghuchoin jal ) and traps (bitte and kholsun) (Table 1). No S2, S3 and S4) of Bishkhali River. Twelve fishermen were previous study on fishing gears was available in the hired temporarily, three from S1, S2, S3 and S4 each Bishkhali River and thus comparison of present findings operating current jal, jagat ber jal and badha jal under the with previous one was not possible. However, same group of gill net, seine net and fixed purse net, respectively numbers of fishing gears were also observed from Lohalia following lunar periodicity (full moon and new moon) and (Ali et al., 2014), Meghna river (Siddique et al., 2013) and during these periods higher abundance of fishes were Tista river (Khan et al., (2013), but lower numbers of reported by the fishermen and fish vendors. Fish samples fishing gears were recorded from Dogger Beel (Siddiq et al., were also collected from the local fish landing centers and 2013) and Shitalakshya river (Miah et al., 2010). fish markets from previously contacted fishermen. Total Mesh size of the nets varied depending mostly on numbers of individual species were counted in each targeted fish species as well as, water body and seasons. sampling day from these stations. From Table 1, maximum (10 to 12 cm) and minimum (0.2 For laboratory study, 30% of the total catch was taken to 0.3 cm) mesh size was found in the case of ilish jal and from each sampling station and preserved in 10% buffered char jal under the group of gill net and fixed net. Present formalin solution in a previously leveled plastic jars findings on mesh sizes were supported by other studies (Ali according to species and size. In the laboratory, the et al., 2014; Siddiqu et al., 2013). collected specimens were identified to species level with the help of standard taxonomic keys of Talwar and Jhingran (1991), Nelson (1994), Rahman (2005) and Hossain et al. Species assemblages (2007). Fish Base software was also used as a guide. A total of 51 species belonging to 11 orders, 27 families and 42 genera were identified during the study period (Figure 2 and Table 2).