GROWTH OF CHANNEL CATFISH IN MIXED-SEX AND MONOSEX POND CULTURE

Growth of male and female channel catfish (Ictalurus punctatus) was mo nitored for 6 months in triplicate 0.04-ha ponds (7500 fish/ha) stocke d with mixed sexes (60-65% male), monosex males (90-98% male) or monos ex females (98-100% female). Average weight and length and total weigh t were not different among treatment groups at any of the monthly samp les. Harvest size of males was similar in ponds stocked with mixed sex es (mean +/- s.e.; 579 +/- 10 g and 324 +/- 2 mm, n = 184), monosex ma les (596 +/- 9 g and 326 +/- 2 mm, n = 282) and monosex females (607 /- 48 g and 333 +/- 6 mm, n = 3), parallel to the pattern observed for females in ponds stocked with mixed sexes (474 +/- 10 g and 305 +/- 2 mm, n = 116), monosex males (458 +/- 21 g and 302 +/- 5 mm, n = 18) a nd monosex females (494 +/- 7 g and 311 +/- 1 mm, n = 297). Males were significantly heavier and longer than females in ponds with mixed sex es and with monosex males, but females and the small number of males i n monosex female ponds were not statistically different in size. Feed conversion efficiencies were similar among treatment groups at each mo nthly sample, but the overall average for ponds with monosex males (0. 743 +/- 0.01) was significantly higher than ponds with mixed sexes (0. 670 +/- 0.02) and monosex females (0.676 +/- 0.01). Intrinsic growth p atterns for both sexes were retained in monosex and mixed sex culture, demonstrating that the superior growth of males has a genetic compone nt and is not due simply to more aggressive feeding behavior. The aver age weight of channel catfish harvested from monosex male ponds was ab out 8.5% higher than fish in mixed sex ponds and 15% higher than fish in monosex female ponds, suggesting that culture of monosex male chann el catfish could provide an economic benefit.