~ 548 ~ International Journal of Fisheries and Aquatic Studies 2016; 4(3): 548-551 ISSN: 2347-5129 (ICV-Poland) Impact Value: 5.62 (GIF) Impact Factor: 0.352 IJFAS 2016; 4(3): 548-551 © 2016 IJFAS www.fisheriesjournal.com Received: 19-03-2016 Accepted: 20-04-2016 Snigdha Chakraborty Research Scholar, Department of Zoology, Gauhati University, India. MM Goswami Professor (Retd.), Department of Zoology, Gauhati University, Guwahati-14, India. Correspondence Snigdha Chakraborty Research Scholar, Department of Zoology, Gauhati University, India. Length- Weight relationship and relative condition factor of Peacock eel (Macrognathus aral (Bloch and Schneider, 1801) from Dora Wetland of Assam Snigdha Chakraborty and MM Goswami Abstract Macrognathus aral (Bloch and Schneider, 1801) commonly known as peacock eel belongs to the family Mastacembelidae. The present study describes the length-weight relationship of the fish collected from Dora Beel. A total of 94 specimens were investigated in the study. The fishes were separated into male and female to calculate length- weight relationship of each individual of the species. The growth performance in both male & female are found high since the correlation co-efficient ‘r’ exhibits high degree of correlation between the length-weight relationships. The correlation co-efficient ‘r’ in Macrognathus aral is closer to 1.0. The length-weight relationship showed a positive allometric growth in both sexes of this species. Keywords: Dora beel, Macrognathus aral, allometric growth, correlation. 1. Introduction The standard spiny eel Macrognathus aral (Bloch and Schneider, 1801) is commonly known as peacock eel. The body of the fish is long and eel like with a long fleshy snout and a rounded tail fin which is separated from dorsal and anal fin. The body color is brownish to yellowish ventrally and marked with two long dark bands on either side of the body. There are 3-11 ocelli at the base of the dorsal fin. Both the dorsal and caudal fins have several fine streaks. This species is distributed to India, Pakistan, Bangladesh, Sri Lanka, Myanmar and Nepal (Talwar and Jhingran, 1991) [32] . Macrognathus aral has high demand as an ornamental fish as well as in the export market due to its playful behavior, brilliant coloration and eye-catching body shape (Das and Kalita, 2003) [10] . Since it is difficult and time consuming to record weight in the field, length-weight relationship is extensively used in the analysis of fishery data (Andrade and Camos, 2002) [2] . The relationship is frequently used to convert growth in length equation for prediction of weight at age and used in stock assessment models (Pauly, 1930) [27] . Length and weight of fish are very important morphometric characters which can be used for the purpose of taxonomy and fish stock assessment (Goel et al., 2011) [15] . According to Arslan et al (2004) [4] , it is easier to measure length than weight and weight can be predicted later on using the length-weight relationship. A variation from the expected weight or length of an individual or group of fish indicates the general well-being and state of gonadal development (Mathur and Bhatara, 2007) [26] . The condition factor gives information on well- being of a fish. It is based on the hypothesis that havier fish of a given length are in better condition (Bagenal and Tesch, 1978) [6] . The condition factor also used as an index of growth and feeding intensity (Fagade, 1979) [13] . Fish specimens of a given length, exhibiting higher weight are said to be in better condition (Anyanwu et al., 2007) [3] . The study on length-weight relationship is still scanty for most tropical and sub- tropical fish species. (Martine- Smith, 1996; Harrison, 2009; Ecoutin et al., 2005; Hossain et al., 2009 a & b) [25, 16, 12, 19, 20] . So far not much work has been done on Mastacembelidae family from this north eastern region of India. So the present study aims to provide information on length-weight relationship and relative condition factor of Macrognathus aral from Dora wetland of Assam. 2. Materials and Methods 2.1 Study Site: The study area, Dora wetland (beel) is situated in Kamrup district, Assam. It is a floodplain wetland in the south bank of river Brahmaputra.