Circadian self-feeding rhythms in greater amberjack Seriola dumerili (Risso)
Abstract:In the present study, 10 greater amberjack Seriola dumerili held individually were given free access to self-feeder, and trigger actuations were continuously monitored. Most (80%) of greater amberjack developed stable self-feeding activity within 1 week. The fish was a rigidly diurnal feeder under a 12L:12D cycle, with a feeding peak of 1–3 h occurring just after the onset of lights. Under constant conditions, all 10 individual fish exhibited free-running self-feeding rhythms, which persisted for 43 days without a sign of damping out. As far as is known, this seems to be the longest record of free-running behavioural rhythms in fishes. Except one fish free-ran at a period length () of 25·2 h, of free-running self-feeding rhythms in the other nine fish was shorter than 24 h, ranging from 20·0 h to 21·5 h. In addition, phase transients of feeding activity were observed in response to the advancement of lights on. It is concluded that feeding activity in greater amberjack is mediated by endogenous circadian oscillators.
Document Type: Regular Paper
Affiliations: Oita Marine Biological Technology Center, Central Research Laboratories, Nippon Suisan Kaisha, Ltd, 508-8 Ariakeura, Oaza, Tsurumi, Saiki, Oita 876-1204, Japan
Publication date: 2007-02-01