Autumn feeding cycle of the bull-dog fish, <i>Gnathonemus macrolepidotus</i> (Pisces, mormyridae)

Abstract

It is often postulated that the time of day at which a fish is caught may influence the measured food volume and composition, but little is actually known about the dimensions of this 24-hourly rhythm (Darnell & Meierotto 1962, Keast & Welsh 1968). The rhythm may vary considerably due to habitat circumstances and generalizations must therefore be made with great caution. In order to evaluate the influence on the feeding cycle of the bull-dog fish, Gnathonemus macrolepidotus, a 24-hour study was undertaken in Loskop Dam, Transvaal, starting on 1 April 1970.