White background stimulates the food intake of a pleuronectiform fish the barfin flounder, Verasper moseri (Jordan and Gilbert).

摘要

In the present study, in order to examine whether a white background stimulates feed intake of barfin flounder (Verasper moseri) or not, we compared the self-feeding activity and somatic growth of fish reared in white or black tanks under natural photoperiod and water temperature (Experiment 1). We further examined the effects of background colour (white and black) on feed intake of individual fish under artificial conditions (Experiment 2). In Experiment 1, total length (TL) and body weight (BW) of fish were significantly higher in the white tank than in the black tank on Days 28 and 50. The number of daily self-feeder activations and specific growth rate (SGR) were significantly higher in the white tank than in the black tank. The results indicate that a white background stimulates self-feeding behaviour and somatic growth in barfin flounder. In Experiment 2, although no significant differences were observed in TL, BW was significantly higher in the white tank than in the black tank on Day 15. Feed intake (g/fish/day) was significantly higher in the white tank than in the black tank in Phase I. Feed intake decreased significantly when fish were transported from the white (Phase I) to the black tank (Phase II). Feed intake tended to be higher in the white tank than in the black tank in Phase II (Fig. 4). These results also indicate that a white background stimulates feed intake and somatic growth in barfin flounder. It is necessary to confirm this result by using larger tanks so that it may be applied to barfin flounder culture in the future.