DIFFERENTIAL DIGESTIBILITIES OF CHANNEL CATFISH, BLUEGILL, AND GIZZARD SHAD - INVITRO STANDARDS FOR GASTRIC DIGESTION BY SEABIRDS

I determined relative rates of digestion of three fish species in vitro by mimicking the gastric juices of piscivorous birds. Bluegill (Lepomis macrochirus) were digested more slowly than Channel Catfish (Ictalurus punctatus) and Gizzard Shad (Dorosoma cepedianum). Digestion kinetics of Bluegill were linear; those of Channel Catfish and Gizzard Shad nonlinear. These digestibility data may be used to predict in vivo digestibility, to correct estimates of food habits of individuals in field studies where gut contents are sampled, or to estimate nutritional contribution of different fish to the diets of birds.