Fish-to-Fish Attraction and the Facilitation of Feeding Behavior as Mediated by Visual Stimuli in Striped Mullet, Mugil cephalus

Abstract

Single juvenile striped mullet, Mugil cephalus, tested in a specially designed experimental tank system, were allowed visual contact with a group of fish located in one of four adjacent tanks. Attraction of mullet isolates was greatest to a group of species mates, and less to bluefish, Pomatomus saltatrix, and Atlantic mackerel, Scomber scombrus, groups, respectively.To study the role of visual stimuli in feeding behavior, responses of mullet isolates were measured under three different test conditions: 1) absence of a group of species mates, 2) presence of a feeding group, and 3) presence of a nonfeeding group. Isolates tested in the absence of a group began feeding only after some delay, although the total number of subsequent feeding responses remained high. When isolates viewed a feeding group, the initiation of feeding was greatly facilitated, with the total number of feedings remaining high until the latter part of a test. Isolates viewing a nonfeeding group showed inhibition in the latency to feed as well as a low number of grazing responses. The significance of these observed responses is discussed.