Effects of Winter Feeding of Channel Catfish on Production in Multibatch Systems

Abstract

AbstractMost channel catfish Ictalurus punctatus are produced in multibatch production systems, but winter feeding studies typically have used single‐batch systems. Winter feeding studies that reflect commercial production practices are needed. Two pond studies (winters of 2005–2006 [study 1] and 2006–2007 [study 2]) were conducted in ten 0.10‐ha ponds; fish in five ponds received feed, whereas fish in the five remaining ponds did not. Ponds were stocked with sub‐market‐sized (<0.57 kg) channel catfish at a rate of 2,957 kg/ha and market‐sized fish (>0.57 kg) at 986 kg/ha. Net yield (kg/ha) in both treatment and control ponds was negative over both winters. The decrease in net yield of fish was significantly less in ponds that received feed than in those that did not receive feed in study 2; the decrease in net yield did not differ between treatments in study 1, which had a colder winter and fewer feeding days than study 2. There was no significant difference in mean weight at harvest for market‐sized fish in fed and unfed treatments, but sub‐market‐sized fish in the fed treatment were significantly larger than those in the unfed treatment. A disease challenge conducted in aquaria showed that mortality after exposure to Edwardsiella ictaluri was significantly higher for unfed fish than for fed fish. Six concrete vats were used to measure feed consumption during the winter of 2007–2008. Channel catfish continued to feed at temperatures as low as 7°C. The amount of feed consumed (expressed as a percentage of body weight) was similar to published recommendations, but fish continued to consume feed daily at lower temperatures than previously assumed. Additional research is needed to determine an optimal frequency of winter feeding.Received February 23, 2010; accepted July 24, 2010