Publication Abstract

The role of gastric evacuation experiments in quantifying the feeding rates of predatory fish

P.J. Bromley

Food is usually broken down in the stomach of carnivorous fish through a combination of muscular contractions of the stomach wall and enzymatic action in an acid medium. Breakdown products areexpelld from the stomach through the pyloric sphincter into the small intestine in a process called gastric evacuation. Digestion and food absorption are completed in the small intestine and rectum. Gastric evacuation is mediated by nervous and hormonal control, including feedback mechanisms. A few studies have investigated the physiological mechanisms involved, but much of the theoretical basis for the subject is borrowed from mammalian studies.

gastric evacuation experiments have been undertaken on a wide range of fish, mainly teleosts, but including some elasmobranchs, fish of marine and freshwater habit, with wild and cultivated representatives. A few groups of fish have been particularly well studied. These include salmonids, flatfish, sunfish and the gadoids. In some species the stomach is absent or not clearly defined, and modifications to the techniques described in this paper need to be made in order to investigate the transit of food through the alimentary canal of such fish.

Reference:

P.J. Bromley, 1994. The role of gastric evacuation experiments in quantifying the feeding rates of predatory fish. Reviews in Fish Biology and Fisheries, 4: 36-66.