Effects of Commercial Feed Provision on Live Prey Selection By Juvenile Channel Catfish

Commercial feeds are commonly added to ponds to enhance juvenile fish growth and survival.  However, the effects of commercial feed provision on fish diets during early life are virtually unknown.  We present results from an experiment that quantified the effects of three different rates of commercial feed provision (no feeding, 1%, or 3% body weight/day) on diet composition, live prey selection, and growth of 14–70 day-old channel catfish (Ictalurus punctatus) reared in ponds.  We found that commercial feed supplemented the diets and enhanced fish growth relative to the no-feeding treatment.  However, diet composition and live prey selection by fish did not differ across feeding treatments.  Surprisingly, all fish ate mainly chironomid larvae during the early weeks in ponds, and then switched to cladoceran zooplankton among live prey.  Because live prey items are likely important for growth of channel catfish and most other fishes during early life, we conclude that zooplankton populations should be carefully managed in rearing ponds, especially those that receive feed additions. To develop the most effective pond fertilization and feeding methods for any species, future studies should quantify the relative importance of live prey and feed for fish growth during early life.