Since 1966,1 a study has been conducted in earthen ponds of the Auburn University Agricultural Experiment Station, Auburn, Alabama, to evaluate the potential of suspended cages for culturing catfish, Ictalurus punctatus (Rafinesque), from fingerlings to marketable size, and to develop the basic techniques necessary for the extension of the culture. This paper presents the developments obtained in the study. Experiments on effects of stocking density per volume of cage, cage positioning relative to the environment and to other cages, and cage mesh size on production are discussed. Observations on feeding behavior, feeding enclosures, feed efficiency, cage materials, cage covers, parasites and disease and other aspects of cage culture are discussed to a limited extent. Stocking densities tested ranged up to 500 fish per mS of cage. The highest standing crop produced was 421 lb. per mS cage stocked with 500 fish. In a 40-day period these fish grew from a mean weight of 0.43 lb. to a mean weight of 0.83 lb. The mean weight gained per mS cage per day was 4.94 lb.; feed conversion was 1.34 using floating pelleted feed. Cage positions in ponds relative to other cages and to exposure to wind induced water currents of open water were found to have an effect on production of fish in those cages. Cages enclosed with 0.25-inch mesh hardware cloth were found to be significantly inferior to cages enclosed with 0.50-inch mesh for raising channel catfish. From these and other results, frequency of water exchange was considered to be a major limiting factor in production of channel catfish in cages suspended in ponds. For all experiments during 1967 and 1968, a net total of 10, 121 lb. of fish was produced with 12,713 lb. of feed for a conversion of 1.25. The lowest mean feed conversion was 1.03 (range of 0.97 to 1.09) among three replications of a treatment stocked at 300 fish per mS of cage. Wood and hardware cloth have certain characteristics that make each undesirable as ultimate cage construction materials. In each of 2 years, approximately 2,000 lb. of channel catfish in cages and 200 to 400 lb. of other fishes in open water were produced per surface acre of pond. Observations indicate that channel catfish in cages are more susceptible to mortalities as a result of low oxygen-high free carbon dioxide concentrations in ponds than tolerated by fishes in open water of those ponds. Indications are that bacterial diseases may be another major limiting factor to the culture of channel catfish in cages suspended in ponds.
