Boldness Impairs Spatial Learning Ability in Brook Trout

Fish populations display high inter-individual variation in behavior. Heterogeneity can often be attributable to the presence of individuals with different behavioral temperaments (defined as a suite of behavioral traits that co-vary across time and space). For example, within the bold-shy axis, boldness is correlated to higher levels of exploration, risk-taking, and aggression. How boldness influences learning and decision making has been tested in terrestrial animals, but little work has explored this in fish. We investigated the ability of shy and bold brook trout to use spatial cues to find and track food in a four-armed maze. Fish were trained for five days to find a hidden food patch which was associated with a visual landmark. The location of the landmark and food were subsequently moved, and the searching strategy of the fish was analyzed to determine if boldness influenced the ability to use landmarks. There was a negative correlation between boldness and time spent in the maze arm with the visual cue. Further, bold fish performed poorly during training, suggesting they were slower to learn the location of food. Taken together, this study indicates that bold fish rely less on spatial cues to locate areas of preferred habitat.