Quantitative analysis and modelling of the behavioural dynamics of Salvelinus fontinalis (brook trout)

Behavioural sequences of juvenile brook trout Salvelinus fontinalis were in vestigated by time-lapse video-recording in the laboratory. A repertoire of six behavioural states was considered. Time-dependent probabilities of bei ng in a given state, staying in the same state or changing of state, were d erived from the behavioural profiles recorded continuously over time for ea ch fish, during 2 h on 2 days. A two-way factorial design with doubly repea ted measures was applied to test the effects of stocking density (3 vs. 6 f ish.150 l), ration level (1.2 vs. 2.5%), feeding (before vs. after feeding) and time on these time-dependent probabilities. Feeding and time affected significantly the transition probabilities. A state space model was introdu ced using the estimated time-dependent probabilities to capture the tempora l structure of fish behaviour. The generated forecasts corresponded well to observed fish behaviour with R'(2) greater than or equal to 0.50 for four behavioural states. (C) 1999 Elsevier Science B.V. All rights reserved.