Fleur Visser

I am interested in the social behaviour and ecology of marine mammals, and how these can be affected by human influences. My current research focus is on understanding the effects of man-made sounds on the social behaviour of cetaceans. Most marine mammals are highly social species. They live in groups and to a large extent depend on group members for foraging, protection from predators, access to females and alloparental care. Social behaviour can therefore be a strong driver of population health. Sound is of fundamental importance for many aspects of cetacean behaviour and ecology. Many species rely on echolocation to find prey, and on vocalisations and hearing for communication with conspecifics. Man-made noise can have severe effects on various aspects of these behaviours, ranging from the masking of sounds to, in the extreme case, strandings. These interferences can negatively affect survival and reproductive success. I investigate sound effects on cetacean behaviour within the larger framework of Behavioural Response Studies, international, multidisciplinary research projects which aim to study the effect of naval sonar on cetacean behaviour. I link different measures of behaviour, measured at both group and individual level, to gain an understanding of behavioural changes in response to a disturbance. The study of natural behaviour is at the centre of this study: the concept of ‘change’ is not only relevant in terms of responses to disturbances; it is also a characteristic of natural behaviour. Therefore, the interpretation and evaluation of behaviouralresponses will rely on underlying knowledge of natural behavioural patterns.