Inclusion of Pangasiid Catfish in Polycultures of Major Indian Carps (Catla, Rohu and Mrigal) Increases Yield and Economic Gain

摘要

An experiment was conducted in twelve 0.02-ha rain-fed earthen ponds for 18 weeks to evaluate the effects of including pangasiid catfish (Pangasius hypophthalmus) in poly cultures of major Indian carps, catla (Catla catla}, rohu (Labeo rohita), and mrigal (Cirrhinus cirrhosus), on yield and economic gain. Treatment 1 (T_1) consisted of 5,000 catla+2,500 rohu+2,500 mrigal per ha, treatment 2 (T_2) consisted of 5,000 catla+2,500 rohu+2,500 mrigal+2,500 pangasiid catfish per ha, treatment 3 (T_3) consisted of 5,000 catla+2,500 rohu+2,500 mrigal + 5,000 pangasiid catfish per ha, and treatment 4 (T_4) consisted of 5,000 catla+2,500 rohu+2,500 mrigal+7,500 pangasiid catfish per ha. The growth performance of fishes was evaluated by calculating specific growth rate, daily weight gain, and percent weight gain. Inclusion of pangasiid catfish in the carp polyculture resulted in significant increases in the growth and yield of catla and rohu. Catla and rohu grew most in T_4, with 7,500/ha of pangasiid catfish.The presence of pangasiid catfish did not influence the growth of mrigal. The growth of pangasiid catfish varied with stocking density, and they grew best at 5,000/ha (T_3). The carp and the combined fish yields were significantly higher in the carp polycultures with pangasiid catfish than with carps alone. The total carp and the combined fish yields were highest in T_4, in which the density of pangasiid catfish was greatest. However, the total carp and the combined fish yields in T_3 and T_4 were notsignificantly different. Profit differed significantly among treatments. Economic gain was highest in T_3, with 5,000/ha of pangasiid catfish, and lowest in TI. The inclusion of pangasiid catfish in major carp polycultures results in higher fish yields and greater economic gain.