Effect of Using Threadfin Shad as Forage for Channel Catfish Fed Daily or Every Third Day

Abstract

AbstractWe evaluated whether stocking threadfin shad Dorosoma petenense as a forage fish in multiple‐batch production ponds for channel catfish Ictalurus punctatus could substitute for formulated feed when channel catfish were fed daily or every 3 d. A completely randomized design in a 2 × 2 factorial arrangement was used for the experiment, which was conducted in twelve 0.1‐ha earthen ponds. Prespawn adult threadfin shad were stocked at 404 kg/ha in six of the ponds, whereas the remaining ponds received no threadfin shad. Channel catfish stockers (0.35 kg/fish) were stocked at 5,040 kg/ha, and fingerlings (28.2 g/fish) were stocked at 14,820 fish/ha. Channel catfish were fed a floating feed (32% protein) to apparent satiation daily (D; 6 ponds) or every 3 d (3D; 6 ponds). After 144 d, mean channel catfish total net yield was unaffected by the presence of threadfin shad but was significantly greater for fish in the D treatment (7,256 kg/ha) than for fish in the 3D treatment (2,431 kg/ha). Mean fish weight at harvest also was greater in the D treatment than in the 3D treatment. The amount of feed administered in the 3D treatment was 62% of that used in the D treatment, thus reducing net total yield by 66% and slowing growth in fish from the 3D treatment. Nearly 90% of stockers in the 3D treatment failed to reach market size (0.68 kg/fish) and would have required a third season to reach harvest weight. At the rate used in this experiment, stocking of threadfin shad as forage fish into channel catfish production ponds did not appear to be a viable method of substituting for formulated feed during the growing season.