Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 13, 2005
Publication Date: January 2, 2006
Citation: Pearson, P.R., Duke, S.E., Green, B.W., Minchew, C.D., Beecham, R.V., Kim, J.M. 2006. Evaluation of a diffused oxygen aeration system under on-farm harvest conditions. North American Journal of Aquaculture. 68:47-52.
Channel catfish are typically raised in large earthen culture ponds, and are harvested by using a large seine to move the fish into one corner of the pond. The fish are transferred from the seine to a smaller grading net, where they are held overnight. Grading nets are designed to hold food-size catfish, while smaller, or sub-marketable catfish escape through the mesh sides. During hot summer weather, the oxygen dissolved in culture pond water may be quickly consumed by the confined fish. Catfish producers attempt to provide more oxygen to the fish by using a tractor-powered paddlewheel to move a current of aerated water through a loaded grading net. In 2004, the aeration effectiveness of a new technology using diffused oxygen to provide supplemental oxygen to catfish held in grading nets was compared to the aeration effectiveness of a tractor-powered paddlewheel. Data collected on six channel catfish harvests showed that performance of the diffused oxygen system equaled or exceeded that of a tractor-powered paddlewheel. An informal economic analysis showed that a diffused oxygen system can be operated for about the same cost per hour as a tractor-powered paddlewheel. Results of the study indicate that the diffused oxygen system is a viable alternative to the tractor-powered paddlewheel for aeration of channel catfish in grading nets.
The aeration effectiveness of a diffused oxygen system was compared to that of a tractor-powered paddlewheel during eight channel catfish Ictalurus punctatus harvests at Top Cat II Fishery in Chicot County Arkansas. Dissolved oxygen and water temperature data were collected from a grading net aerated by the diffused oxygen system, from a grading net aerated by a paddlewheel, and from the open culture pond between the two grading nets, and were not significantly different. However, comparison of estimated oxygen consumption by the biomass confined in each grading net indicated that the aeration effectiveness of the diffused oxygen system equaled or exceeded that of a paddlewheel on six field trials. An informal cost comparison indicated that a diffused oxygen system can be put in service for a smaller capital investment than a tractor-powered paddlewheel, and that the hourly operating expense of the diffused oxygen system is comparable to that of the paddlewheel. Results of the study indicate that the diffused oxygen system is a viable alternative to the tractor-powered paddlewheel for aeration of channel catfish held in grading nets.