~ 640 ~ Journal of Entomology and Zoology Studies 2018; 6(1): 640-645 E-ISSN: 2320-7078 P-ISSN: 2349-6800 JEZS 2018; 6(1): 640-645 © 2018 JEZS Received: 28-11-2017 Accepted: 29-12-2017 Naresh Raj Keer 1) Department of Aquaculture, College of Fisheries, CAU (I), Lembucherra, Agartala, Tripura, India 2) Division of Aquaculture, ICAR - Central Institute of Fisheries Education, Versova, Mumbai, Maharashtra, India Mrinal Kanti Datta Department of Aquaculture, College of Fisheries, CAU (I), Lembucherra, Agartala, Tripura, India Arun Bhai Patel Department of Aquaculture, College of Fisheries, CAU (I), Lembucherra, Agartala, Tripura, India Raj Priyanka Rathor Department of aquaculture, College of Fisheries, MPUAT, Rajasthan, India Manmohan Kumar 1) Department of Aquaculture, College of Fisheries, CAU (I), Lembucherra, Agartala, Tripura, India 2) Division of Aquaculture, ICAR - Central Institute of Fisheries Education, Versova, Mumbai, Maharashtra, India Satyajit Das Department of Aquaculture, College of Fisheries, CAU (I), Lembucherra, Agartala, Tripura, India Correspondence Naresh Raj Keer 1) Department of Aquaculture, College of Fisheries, CAU (I), Lembucherra, Agartala, Tripura, India 2) Division of Aquaculture, ICAR - Central Institute of Fisheries Education, Versova, Mumbai, Maharashtra, India Effect of stocking density on growth and survival of Cirrhinus reba (Hamilton, 1822) during spawn to fry nursing (outdoor) Naresh Raj Keer, Mrinal Kanti Datta, Arun Bhai Patel, Raj Priyanka Rathor, Manmohan Kumar and Satyajit Das Abstract To study the effects of stocking density of Cirrhinus reba (Reba carp) in nursing of spawn for 15 days on growth performance, survival and digestive enzyme’s activities were studied from 7 th to 22 nd July, 2015. The present experiment was conducted in 20 m 3 tanks in triplicate at the College of Fisheries, Lembucherra. Three different treatments @ T1: 3.0; T2: 5.0 and T3: 7.0 lakh spawn ha -1 and fed with 30% protein diet. Significantly (p<0.05) highest mean final weight (0.77±0.00 g), final length (3.74±0.21 cm), survival (55.80±0.81%), protease activity (1.32 units/ mg protein/ min), lowest AFCR (0.57±0.02) and highest APER (5.80±0.17) was found in the in T1 with lowest stocking density (3 million ha -1 ) in nursery rearing of spawn. There were no significant difference ( p>0.05) observed in condition factor, hepato-somatic index and relative fatness. Thus, 3 million spawn ha -1 appear to be most suitable stocking density for nursing of Reba. Keywords: AFCR, Cirrhinus reba, digestive enzyme’s activities, relative fatness, spawn 1. Introduction Reba carp, Cirrhinus reba is an important food fish, which is distributed over Indian sub- continent [27, 34, 42] . It is locally known as bhagna bata, raik or tatkini, and considered as one of the most important indigenous minor carp species. The natural production of Reba has declined considerably due to increased fishing pressure and various anthropological activities leading to siltation, aquatic pollution, and loss of natural habitat for spawning and growth [23] . Reba carp mainly inhabits in rivers and clear streams but is also found in tanks, canals, ponds, beels and inundated fields [33, 34, 42] . It is primarily plankton feeder but also feeds on detritus, mud, vegetables, crustaceans and insect larvae [42] . Spawning season of Reba carp is April to August with peak spawning occurring during the monsoon season [1, 23] . Relative fecundity of Reba carp was documented between 2.0-2.5 lakh egg kg -1 body weight of female [23] . Stocking density is related to number of fishes stocked in per unit of volume. It is an important parameter in aquaculture, since it has direct effect on the growth and survival and hence production [4] . Stocking density is an important indicator that determines the economic viability of the culture system. Positive effect of stocking density on growth is reported in some species and it is critical factor for many aquatic animals for their growth and survival [37, 45] . Decrease in stocking density results in decrease stress, which leads to lower energy requirements, causing higher growth rate and food utilization in the aquaculture production system. Stocking density is directly related with the competition for food and space in ecosystem [37] . Generally, fish needs to compete less for food and space in lower stocking density than the higher this minor carp is an eco-friendly fish and an important source of proteins, fats, carbohydrates, vitamins and minerals [43] . Its flesh is oily, tasteful and people would like to eat due to its lucrative size, high nutrition, and attractive flavor and less spines [31, 33, 39] . It is a congruous species for aquaculture but the wild population of Reba is rapidly declining due to sundry causes [31, 39] . Hence to meet the increasing demand of protein in India adaptation of semi- intensive and intensive culture practice on some important species of fishes is very important. The present investigation was undertaken to develop a practical and economically viable methodology for mass seed production and nursing of spawn of C. reba under controlled nursery management system in cemented tanks.