Diel feeding rhythms of greenback flounderRhombosolea tapirina(Günther 1862): the role of light-dark cycles and food deprivation

Abstract

The role of light–dark (LD) cycles and food deprivation in the regulation of diel feeding rhythms in greenback flounder Rhombosolea tapirina (Günther 1862) was examined. A computerized monitoring system was developed to record uneaten pellets, and food intake was estimated as the difference between pellets presented and those uneaten. Three groups of five fish each (75–281 g) were exposed sequentially to the LD cycles: LD 12:12, LD 12:12 (scotophase advanced by 9 h), LD 6:18, DD, LD 6:6:6:6, LL and LD 12:12 (return to the initial cycle). Illumination was 120 lux at the water surface (complete darkness at scotophase), and water temperature was 15 ± 1 °C. Fish fed mainly during the light hours under LD 12:12 and resynchronized to the scotophase‐advanced LD 12:12 regime after about 12 h. Feeding started at the onset of light and extended to the early scotophase under LD 6:18. A circadian feeding rhythm was detected in fish under DD and LD 6:6:6:6 regimes. Under the LL regime, two groups of fish displayed arrhythmic feeding patterns and did not resynchronize to LD 12:12 for at least 13 days. In contrast, the third group of fish exhibited a circadian feeding rhythm under the LL regime and immediately re‐entrained to LD 12:12. Fish were deprived of food for a single period of 26–57 h once feeding patterns had been established under LD 12:12, LD 12 : 12 (scotophase advanced by 9 h) and DD regimes, and feed delivery was resumed during the scotophase or subjective night; the timing of feeding rhythms was shifted by the reintroduction of feed, but progressively resynchronized to the LD cycles. The results suggest that the greenback flounder is a diurnal feeder, that a LD 12:12 cycle is a potent environmental cue to entrain circadian feeding rhythms, and that a biological clock is involved in the timing of feeding.

The effect of feeding regime on growth, locomotor activity pattern and the development of food anticipatory activity in greenback flounder

“… sub-optimal. This agreed with field and laboratory observations that greenback flounder prefer to feed during light hours (Crawford, 1984;Chen et al, 1999). The regime of one 3 h meal during photophase (1M/L) resulted in equally good growth as under the other feeding regimes except 1M/D (Table I).…”

“…data). A recent study (Chen et al, 1999) has revealed that the fish prefer to feed during the photophase, but a bout of feeding activity occurs also during the scotophase particularly after a period of food deprivation.…”

Comparative behavior of red lionfish Pterois volitans on native Pacific versus invaded Atlantic coral reefs

“…Changes in diel activity of fishes are a common response to differences in biotic and abiotic environmental factors, including predator abundance, prey availability, presence/absence of competitors, habitat structure, depth, and abiotic conditions such as temperature and light levels (Chen et al 1999, Reebs 2002, Hansen et al 2004, Andrews et al 2009, Côté & Maljković 2010. Because these factors may vary regionally, and because invasion is often accompanied by release from the natural controls of competition and predation (Mack et al 2000), behavioral differences in invasive species are therefore likely between native and invaded locations.…”

A dynamic fish digestion–assimilation model: oxygen consumption and ammonia excretion in response to feeding

“…Ad libitum feeding is often affected by light: some fish are nocturnal feeders (European sea bass: Boujard et al 1996) and some are diurnal (greenback flounder: Chen et al 1999;spotted wolffish: Foss et al 2003). OC and AE inevitably follow the natural feeding pattern; however, if feed is provided at specific times unrelated to the circadian rhythm, fish can often adjust to the imposed schedule (walleye: Yager and Summerfelt 1994; European sea bass: Boujard et al 1996;Azzaydi et al 1998;tench: Zakes et al 2006).…”