The interaction of factors influencing the predatory behaviour of the pike Esox lucius L.
The work submitted in this thesis describes three investigations of the relationship between stimuli, the pike and the pike's inclination to feed. Consideration is given to the importance of relating internal and external factors to the causation of behaviour. The effects of individual pike and the time lapsed after feeding on predatory behaviour are firstly assessed. Use of multivariate analysis determined key behaviours in the repertoire of pike that could be successfully employed in analysing prey-capture sequences. The modifying influence of hunger, as categorised by stomach content, on prey capture sequences is presented and discriminant function analysis is used as a method of describing differences in predatory behaviour. A simple treatment of bout criteria is also given. The interaction of the components of visual stimuli and its influence on predatory response revealed that particular movements and shape of a stimulus altered the attack behaviour of pike. The relative strength of a visual cue, for example, how "fish-like" a stimulus is, has dependence on how inclined an individual is to feed. A view of how these factors influence the behaviour of pike in a wider context is expressed.