'Personality' in two species of temperate damselfish

The extent and importance of consistent individual differences in behaviour, often referred to as 'personality' or 'temperament', is a relatively recent question in ecology. It indicates that animal behaviour is much less flexible than usually assumed, and suggests that individuals consistently differ in the way they perceive and react to changes in the environment. There is evidence of animal personality in a wide variety of animal taxa, including many freshwater fish species, but there seems to be very little evidence for this phenomenon in marine fish. To address this paucity, we repeatedly measured 3 behavioural traits of 2 temperate marine damselfish species, Parma microlepis and P. unifasciata, over a 2 wk period. Consistent individual differences in boldness, aggressiveness and activity were observed in both species, but average levels of these traits did not differ between species. A correlation between personality traits was also observed, with bolder individuals also tending to be more aggressive. The existence of personality in marine fish has implications for practical issues such as sampling bias, vulnerability to harvest and links between personality and life-history traits that affect fitness.