Nocturnal/diurnal demand-feeding pattern of yellowtail Seriola quinqueradiata under different keeping conditions

Abstract

SUMMARY: Demand‐feeding behavior of juvenile yellowtails was examined under two different light conditions: in an experimental room and in the outdoors. In the indoor experiment, five groups of 20 juvenile yellowtails (mean bodyweight, 16.0 g) were allocated individually to five 200 L cylindrical tanks set up in the experimental room. A rod‐type tactile switch was used for activating the feeding device which delivered 5–10 pellets per actuation. Each tank was illuminated by an overhead fluorescent lamp with a LD 12:12 photoperiod regime. In the outdoor experiment, 69 juvenile yellowtails (mean bodyweight, 79.8 g) were allocated to a 7000 L cylindrical tank. A switch with a string that ends in a rubber, pellet‐like knob was used. The feeding device delivered 90–120 pellets by activation of the switch. In both experiments, yellowtail learned demand‐feeding within 1–3 days. The number of feeder actuations gradually increased during the experimental period in both experiments, presumably relating both to the rate of learning and to growth of the fish. The yellowtails in the indoor system showed a clear diurnal feeding pattern synchronizing to the given photoperiod, whereas those in the outdoor system showed a clear nocturnal feeding pattern also synchronizing to the outdoor natural photoperiod. Thus, the results showed that yellowtail has an ability for demand‐feeding both in light and dark phases. These exact opposite results may have been caused by the difference in intensity of the luminance between the inside of the experimental room and the outdoors.

Weaning of greater amberjack (Seriola dumerilii Risso 1810) juveniles from moist to dry pellet

“…In the wild under a natural photoperiod, Japanese yellowtail (Seriola quinqueradiata) is a nocturnal species as it prefers to feed during dawn and dusk (Mitani 1958;Kohbara et al 2000Kohbara et al , 2003. Under our experimental conditions (also under natural photoperiod), greater amberjack consumed more food during the afternoon than during the morning feeding when offered the moisturized diets.…”

Egg-laying patterns and in vivo egg production in the monogenean parasites Heteraxine heterocerca and Benedenia seriolae from Japanese yellowtail Seriola quinqueradiata

“…At this stage it is unclear what host behavioural trait these rhythms are associated with. Kohbara et al (2000) demonstrated that S. quinqueradiata displays a nocturnal feeding pattern when maintained in tanks located outdoors and exposed to natural illumination and, a diurnal feeding pattern when maintained in tanks indoors and exposed to fluorescent illumination. Oxygen consumption by hatchery reared Seriola lalandi peaks at dawn and dusk before declining to a minimum during the night (personal communication).…”

Photic and circadian regulation of self-feeding activity in ayu

“…10,23,27 However, in other studies on rainbow trout photoperiod length under LD affects appetite. 14,18 Studies on rainbow trout, European sea bass and European catfish have shown that both diurnal and nocturnal feeding patterns can occur in the same species depending on experimental conditions and/or time of year, and there is also evidence that both diurnal and nocturnal phasing of feeding can occur among individuals kept under the same conditions.…”