SPECIES COMPOSITION AND ABUNDANCE OF FISH AND PRAWN SPECIES IN ATARAN RIVER, MON STATE Naw Zar Chi Linn1, Than Than Soe2, Win Win Myint3 ABSTRACT The Ataran river, one of the tributaries of the Thanlwin river, was rich both freshwater and brackish fish and prawn species and contribute significantly to a numerous of ecosystem services for inland fisheries. The present research was done to evaluate the species composition and abundance of fish and prawn species along the Ataran river at fish landing sites of Naungbinseik, Ngabyama and Chaungnakwa from December, 2019 to March, 2020. In this research, a total of 47 fish species belonging to 27 families, 41 genera under 13 orders and seven prawn species from two genera of Palaemonidae were recorded and identified. Species numbers and abundance of fish and prawn were highly observed in December while those were lowly in March in all study areas. The highest fish species number was shown by Nyaungbinzeik area (41 species), followed by Chaungnakwa area (37 species) and Ngabyama area (35 species). Relative abundance of fish indicated eight species as very common, 15 species as common and 24 species as uncommon in the study areas. Of the 47 fish species recorded, one species Wallago attu has been assessed as Vulnerable and one endemic species Esomus altus (Fishbase,2017). A toad fish species, Allerbatrachus grunniens (locally called Nga-oak-phar) is for the first record from Ataran river, Mon State. The highest number of recorded prawn species was observed in Chaungnakwa followed by Naungbinzeik and Ngapyama. The highest composition and abundance of prawn species Macrobrachium rosenbergii was observed in all study areas and the lowest in M. malcolmsonii. Relative abundance of prawn indicated four species as very common, two species as common and one species as uncommon in the study areas. Key words: Ataran river, relative abundance, fish, prawn, species. INTRODUCTION Myanmar has a long coast line of (2832) km with many rivers flowing into the extended, so there are a lot of prawn and shrimp fishery resources. In Myanmar, a total of 1107 species of fish (Fishbase, 2017) and 35 species of prawn (Sann Aung and Hla Htay,1986) were recorded. The tributaries of the Thanlwin river are also rich both freshwater and brackish prawn species and a distinctive region for inland fisheries. The inland artisanal fishery is one of the most important components of fishery sector in the study area (Than Than Soe, 2018). The Ataran river is one of the tributaries of the Thanlwin river. It arises by the confluence of the Zami river and Winyaw river at Chaungnakwa area in Mon State and discharges into the Gyine river near Mawlamyine at Thanlwin river mouth. The River is facing tidal intrusion and freshwater discharge so forming estuarine regions and habitats for variety of fresh and brackish fish and prawn faunas. Several fish species from Ataran river were traded as aquarium fish as Botia Kubotai, Parambassis pulcinella, Mictodevario kubotai and Caelatoglanis zonatus (http://en.wikipedia. org/wiki/ Ataran river). The Ataran river is a vital role for lives livelihood of local populace. Fish and prawn fauna of the Ataran river is very important not only for consumption but also for incomes. They are fished by artisanal units and exploited by traditional gears. Fishery resources are sent to neighboring areas and townships for local consumption Although fishery resources of the Ataran river have been exploited for many years, there is little information concerned with these resources. Khin Hla Myint (1997) identified and described 51 species of fish of the Ataran river from Nyaungbinzeik to 1 Dr. Lecturer, Department of Zoology, Mawlamyine University 2 Dr. Lecturer, Department of Zoology, Mawlamyine University 3 Dr. Professor & Head, Department of Zoology Mawlamyine University, 1 Chaungnakwa. Than Than Soe (2012) recorded 17 species of Macrorachium species in the Thanlwin river and adjacent waters were identified. Than Than Soe (2018) also reported one species of Leptocarpus: 14 species of Macrorachium belonging to two genera and one family were recorded in the Thanlwin river and its tributaries as Gyine river and Donthami River. Thus, the present work is aimed to conduct as follow: - to identify the species level of fish and prawn fauna of the Ataran river - to assess fish and prawn composition and abundance from the study areas. MATERIALS AND METHODS Sample collections were carried out at the landing sites of Nyaungbinzeik, Ngabyama and Chaungnakwa which areas are located along the Riverside of the Ataran river. It is generally situated between 16°17´ - 16° 48´ north latitudes and 97°67´ - 97°96´ East Longitudes (Fig.1). The present study was carried out from December, 2019 to March, 2020. Specimens were collected twice (spring tide and neap tide) per month from the local fishermen using bag-net (Kyar-pa-zat), net-fence (la-tar), trammel net (thone-htat-hmaw) at the study areas. The collected samples were recorded and preserved with 10% of formaldehyde solution for future study. The most important morphological characteristics of specimens were observed and identified according to Day (1878), Talwar and Jhingram (1991), Jayaram (2013), Holthuis (1950 and 1980), George (1966), De Bruin et.al (1994), Chan (1998) and Cai and Ng (2002), Hla Phone (2005) and Than Than Soe (2012). Local names of fishes and prawns were recorded according to local fisherfolks. Valid names and IUCN Redlist Status were checked by Fishbase (2017). Fish and prawn samples were sorted out and each category was counted. The percentage composition and monthly abundance of prawns was estimated base on catch per trip. Relative abundance of fish and prawn were calculated by method of Bisht et al. (2004). No .of individuals of species Relative abundance = Totalno. of individuals of all the species The average relative abundance was categorized as by method of Bisht et al. (2004). uC = (uncommon) having relative abundance less than 0.0100 C = (common) having relative abundance of 0.0100 and above but less than 0.0500 vC = (very common) having relative abundance of 0.500 and above 2 97º 39' 97º 45' 97º 51' 97º 57' Thanlwin river Gyine river N 16º 33' Nyaungbinzeik Mawlamyine 16º 27' Kyaikmaraw Ngabyma 16º 21' 16º 15' Chungnakwa f tt a l o u r r w n W f m i y G o M a v 16º 09' i a Study sites e 30 km Zami river Fig.1 Map showing the study areas RESULTS Species composition and relative abundance of prawn and fish species in Nyaungbinzeik area, Ngabyama area and Chaungnakwa area which are situated along the Ataran river was conducted from December, 2019 to March, 2020. During the four months study period, a total (2435 individuals) representing of 47 fish species belonging to 27 families, 41 genera under 13 orders (Table 1). A total of (9521 individuals) of seven prawn species from two genera of Palaemonidae (Table 2). Species composition and relative abundance of recorded fish species in Orders Among the 13 orders concerned in the present work, the order Siluriformes was represented with 11 species (23.40%) is the highest composition fish species followed by Cypriniformes ( n= 9; 19.15%), Perciformes (n= 7; 14.89%), Gobiiformes (n= 5;10.64%), Pleuronectiformes (n= 3; 6.38%), and the orders: Anguilliformes, Clupeiformes, Anabantiformes, Synbranchiformes constituted (n=2; 4.26%) and the lowest in each (2.13%) order Osteoglossiformes, Batrachoidiformes, Cyprinodontiformes and Scorpaeniformes respectively (Table 1). With regard to the different study areas, the total number of all fish species (n=2435) was found to be greater in Chaungnakwa (n=1245) followed by Ngabyama (n= 768) and the least was in Nyaungbinzeik with (n= 422) (Table 4) In the present study, the relative abundance of fish species were calculated and shown in (Table 4) Fish species is very rich in Nyaungbinzeik (total number of 41 species), followed by Chaungnakwa (total number of 37 species), 31 species were found in Ngabyama. In the case of relative abundance of Nyaungbinzeik, five species of fish (A.mola, E. altus. X. cancila and O.pama P.paradiseus ) were taken very common, 27 species as common and 19 species as uncommon. Relative abundance of fish in Ngabyama, seven species of fish (P. chola, 3 A.mola, E. altus, X. cancila , O.binaculatus and G.giuris) were taken very common, nine species as common and 17 species as uncommon. Relative abundance of fish in Chaungnakwa, eight species of fish (O. feae, P. chola, A.mola, E. altus, O.binaculatus X. cancila, G.giuris and M.aral ) were taken very common, seven species as common and 22 species as uncommon. Species composition and relative abundance of recorded prawn species During the study period, a total (9521 individuals) representing of seven prawn species under family Palaemonidae of two genera was recorded. Of which, six Macrobrachium species, one Leptocarpus and various fish species contributed to the artisanal fishery. Seven prawn species except M. malcolmsonii were caught throughout the study period and found in Nyaungbinzeik area, Chaungnakwa area while M. malcolmsonii not occurred in the catches of Ngabyama area. Despite having a higher overall percentage composition than the other species in three difference study areas, Macrobrachium rosenbergii composed of (29.79%) followed Leptocarpus fluminicola composed of (27.26%) , M. lanchesteri (14.82%) M .mirabile (11.24%), M. neglectum (8.63%), and (9.50%), M. lanatum (7.95%), and M. malcolmsonii (0.32%) and the species was formed the bulk of fishery throughout the study period. In the present study, the total number of all prawn species (n=9521) was found to be greater in Chaungnakwa (n=5010; 52.62%) followed by Nyaungbinzeik (n= 2290; 24.04%) and the least was in Ngabyama with (n=2222; 23.34%) (Table 2).