Foraging behaviour of shoaling fishes : information gathering and prey competition

Firstly I investigated the use of asocial and social information use; the potential for inexpensively acquiring information about prey resources is one advantage of social foraging. Threespine sticklebacks (Gasterosteus aculeatus) assimilated and used private information about prey distribution between different social information cues, and when these conflicted with their private information, they based their foraging decisions upon the former, suggesting that there are costs associated with non-conformist foraging behaviour.;Secondly, I investigated prey competition, a major cost associated with social foraging. I found that increasing group stability, and by inference familiarity, led to a decrease in the rate of kleptoparasitic prey competition within shoals when they were foraging for dispersed prey. When prey were concentrated however there was no effect of group stability upon prey competition level. Prey competition was less intense between familiar individuals that were embedded in unfamiliar shoals than it was between these and their unfamiliar shoal mates.;Finally I investigated the role of individual behavioural variation in relation to social information use and prey competition. Boldness across a number of contexts was seen to correlate with individual competitive ability, predicting the outcomes of both inter- and intra-specific prey competition interactions. Interestingly, the use of public information, a risk-averse strategy consistent with the shy behavioural phenotype, was not seen to be related to individual boldness.;The broader significance of the findings of this thesis is considered in the context of previous research, and directions for future work are identified and discussed.