Impact of Minimum Dissolved Oxygen Concentration on Grow‐Out Performance of Blue Catfish with Comparison to Channel Catfish

Abstract

AbstractFeed intake, the feed conversion ratio (FCR), and the production of blue catfish Ictalurus furcatus and channel catfish I. punctatus were examined in 1‐acre ponds maintained at either a high or low minimum dissolved oxygen (DO) concentration (mean values of 4.29 and 2.54 ppm [55% and 32% air saturation], respectively). Two additional studies were conducted examining only blue catfish in 0.25‐acre ponds maintained at either a high (mean values of 4.43 and 4.46 ppm [56% and 55% air saturation] in the two studies) or low (mean values of 1.41 and 1.64 ppm [18% and 20% air saturation]) minimum DO concentration. Blue and channel catfish exhibited similar feed intake (13,432 versus 13,063 lb/acre), growth (1.40 versus 1.49 lb/fish), gross production (6,662 versus 6,663 lb/acre), and net production (5,935 versus 5,813 lb/acre) in the high‐DO treatments in the 1‐acre ponds. Within the low‐DO treatment, feed intake was not significantly different (13,555 versus 12,398 lb/acre for blue and channel catfish, respectively), but both gross production (6,796 versus 5,810 lb/acre) and net production (6,069 versus 4,960 lb/acre) were significantly lower in the channel catfish ponds. The FCR was similar between species (2.25 versus 2.38) and was not affected by DO treatment. In the blue catfish studies in the 0.25‐acre ponds, ponds in the high‐DO treatments had significantly higher feed intake (+23.0% and +33.4% in 2006 and 2007, respectively) and net weight gain (+38.0% versus +42.3%) than those in the low‐DO treatments; both gross production (16,898 versus 12,963 lb/acre) and net production (14,768 versus 10,855 lb/acre) were significantly higher in the high‐DO treatment in 2006. Food conversion ratios averaged 1.86 in 2006 and 2007 and were similar in fish among DO treatments in both years. Data from these and other similar controlled studies indicate that most blue catfish production variables tend to be affected less by low DO concentrations than are channel catfish.