Preliminary Observations on the Cost of Producing Fingerling Channel Catfish, Ictalurus punctatusStocked as Sac Fry or as Hatchery-Fed Swim-Up Fry

Abstract

Some producers of channel catfish, Ictalurus punctatusfingerlings stock sac fry in nursery ponds as early as two days after hatching to reduce hatchery operating costs associated with the traditional practice of feeding swim-up fry for 7–10 days prior to stocking. It is not known if the reduced costs associated with the elimination of hatchery feeding of swim-up fry are countered by reduced production of fingerlings from ponds stocked with unfed sac fry. This study was conducted to determine if stocking catfish fry two days after hatch (unfed sac fry) or 10 days after hatch (hatchery-fed swim-up fry) had significant effects on the subsequent production of fingerlings and the profitability of a fingerling production operation under practical production conditions. In two consecutive years, catfish fry were stocked in 0.08-ha ponds in the spring of the year and harvested about six months later. Sac fry were stocked at a density (mean±SD of both years) of 24,953±2,876/ ha; swim-up fry at a density of 31,473±9,260/ha. Fry were fed a 45%-protein mash for several weeks after stocking and then a 38%-protein crumble for the remainder of the production trial each year. There were no statistically significant (P > 0.05) differences in yield (sac fry, 40±39 kg/pond; swim-up fry, 30±17 kg/pond), number harvested (sac fry, 2,521±2,720 fish/ha; swim-up fry, 1,988±3,059 fish/ha), or survival (sac fry, 10±11%; swim-up fry, 6±9%) of fingerling catfish stocked as either sac fry or swim-up fry. Total annual savings were estimated to be $17,636 (1% of total specified expenses) for a medium-sized hatchery that produced sac fry, compared with a hatchery that produced and fed swim-up fry. Fry survival was a critical factor influencing revenue. In this study, feeding catfish swim-up fry in the hatchery for seven days prior to stocking in ponds for grow-out to fingerling size provided no benefit, in terms of fish survival or the quantity of fingerlings produced, when compared with fingerling yields from ponds stocked with two-day old (unfed) sac fry. Thus, hatchery feeding of swim-up fry may be an uneconomical practice that might be effectively replaced by the stocking of sac fry within 48 hours of hatching. Additional research is needed to determine if the results obtained in this study can be expected to occur under a wider range of production conditions before recommendations on the stocking of catfish sac fry are developed.