Cetacean social behaviour

Marine mammals are highly social species. They live in groups and to a large extent depend on conspecifics for foraging, group defence, alloparental care and access to females. Social behaviour can therefore be a strong driver of population health and there is a growing interest in how behaviours and decision-making processes are structured at the group level. KMR has developed a strong expertise in the study of cetacean social behaviour, by integrated recordings of activities at the surface and under water, including social behaviour, vocalisation, movement and diving patterns.

Effects of man-made noise on cetacean behaviour

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 and detection of predators. 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. The ubiquitous presence, high levels and diversity of man-made noise in the oceans represent a major concern for marine life. There is a pressing need to investigate potential effects of noise in the oceans, to support management measures and to enable mitigation of negative effects. To investigate the effects of sound on cetacean behaviour, KMR collaborates within international and multidisciplinary behavioural response studies.

Developing methodology for group-level research

Groups are ephemeral structures of cetacean societies. Therefore, defining a group, and staying with this group throughout an observation can be challenging. Visual sampling of behaviour also relies on the recording of parameters that can be reliably observed. This is of particular importance for cetaceans, which may perform a large part of their behaviours out of sight. To overcome these sampling difficulties, KMR has developed a sampling protocol that describes the social context of individual behaviour. The protocol uses a dynamic definition of 'group', centred around a focal individual, and an ethogram quantifying directly observable characteristics of the group. The social behaviour sampling protocol is currently applied in several studies and is freely available.

Cetacean ecology and environmental change

Mechanisms for orientation, timing and navigation during migration in cetaceans still largely remain a mystery. If these include environmental cues, such as sea water temperature or prey availability, migration could be affected by the current changes in the environment. We showed that the timing of spring migration of baleen whales at the Azores was determined by the timing of the onset of the spring bloom. The spring bloom is a major biological event, dictated by changes in temperature and light conditions, and known to be sensitive to global warming. These results indicate that climate warming can have fitness effects for migratory whales, as it can affect their potential for feeding during migration.

Cetacean populations and habitat-use

Knowledge on the habitat-use of cetacean populations forms essential information in the designation of protected areas and other management efforts dedicated to their conservation. Coastal populations may be particularly vulnerable. Habitat-use and home ranges of dolphin populations are studied using photo-identification and high resolution tracking techniques, allowing for the identification of dolphin communities, their home ranges and site fidelity, and their ranging patterns.