55 Indian J. Fish., 56(1) : 55-59, 2009 Growth performance of the chocolate mahseer Neolissocheilus hexagonolepis (Mc Clelland) in pond system in Arunachal Pradesh BONI AMIN LASKAR, D. N. DAS 1 AND B. C. TYAGI 2 National Research Centre on Coldwater Fisheries (ICAR) Project station, Government Fish Seed Farm, Lower Dibang Valley District, Roing -792 110, Arunachal Pradesh, India 1 Department of Zoology, Rajiv Gandhi University, Rono Hills, Itanagar, Arunachal Pradesh, India 2 National Research Centre on Coldwater Fisheries (ICAR), Bhimtal, Nainital District, Uttaranchal - 263 136, India e-mail: aminboni@rediffmail.com, aminboni@gmail.com ABSTRACT Growth performance of the chocolate mahseer Neolissocheilus hexagonolepis (Mc Clelland) cultured in an earthen pond was studied separately for adults and yearlings in terms of specific growth rate and net length gain during October 2003 - June 2004 and September 2004 - August 2005, respectively. Forty five adult fishes having an average length of 190.30 mm and average weight of 88.05 g were cultured in the pond at a stocking density of 1 no. /13.4 m 2 . The gross increment in size of adult fishes after 278 days of culture was 82.87 mm (29.80% days) in length and 119.01 g in weight. Four hundred fifty numbers of yearlings of average length 127.39 mm and weight 19.58 g were cultured at a stocking density of 1no. /1.34 m 2 for 333 days. The yearlings gained a net length of 78.86 mm and a net weight of 61.40 g. Key words : Neolissocheilus hexagonolepis, Chocolate mahseer, Growth, Pond system The mahseers are very important hill stream carps. They provide constant source of unparallel recreation to innumerable sportsmen from home as well as from abroad. Mahseers are also valuable food fishes and play an important role in the nutrition of the people especially in the hilly regions of India. Arunachal Pradesh (A. P.), the most eastern state of India, harbours three species of the total seven Indian mahseers. Our survey on mahseer in Dibang valley district of A. P. (N 28 0 10 / ; E 95 0 20 / to 96 0 40 / ; alt. 150 to 5300 msl) (Fig. 1) encountered two species viz., Neolissocheilus hexagonoplepis, the chocolate mahseer and Tor putitora, the golden mahseer. N. hexagonoplepis is commonly called by local Idu-Mishmi tribal people as “Abro”. But in nearby area, it is called as "Buka pitia" by Assamesse people and as "Katli" by Bengalese in North Bengal and Nepalese in Sikim. Mahseer fishery in the Indian sub-continent is constituted by seven species, out of which six species are placed under the genus Tor. In the existing milieu, lots of information are available on T. khudree, T. mussullah, T. tor and T. putitora (Karamchandani, 1967; Desai, 1970; Kulkarni, 1971; Chaturvedi, 1976; Kulkarni and Ogale, 1978; Nautiyal and Lal, 1984,1985; Sehgal, 1999; Ogale, 1997, 2002). Some information on the general biology Note Fig. 1. Map of Dibang Valley and Lower Dibang Valley showing the principal rivers and streams