Abstract

Fish fed using demand feeders often display highly variable feeding activity across days. In order to quantify this pattern, data from 10 groups of self-feeding rainbow trout, Oncorhynchus mykiss (Walbaum), with a mean start weight of 30-120 g were examined for repeating patterns using time series analysis. The number of bites on a self-feeding trigger were recorded and summarised on both an hourly and daily basis. Significant peaks in trigger-biting activity occurred in the morning and evening at lights on and lights off. It is suggested that this activity pattern corresponds to an evolutionary trade-off between predation risk and feed availability. Across days, peaks in trigger-biting activity are significantly higher every second day. A possible explanation for this pattern is the time required for gastric evacuation and the return of appetite. (c) 2005 Elsevier B.V. All rights reserved

Keywords

Time series; Behavioural patterns; Self-feeding activity; Rainbow trout; Oncorhynchus mykiss; Appetite

Published in

Aquaculture
2006, volume: 254, number: 1-4, pages: 355-360
Publisher: ELSEVIER SCIENCE BV

Authors' information