Samenvatting

Azorean waters have long been known to be inhabited by a vast number of cetacean species, representing a hotspot for marine wildlife within the North Atlantic. Various ecological factors are related to the complex habitat requirements of marine species such as water temperature, physiography and presence of prey. Rhythmic patterns created by environmental cycles such as lunar and tidal phases generate and influence ocean currents. These, in turn, indirectly influence the movement patterns of prey species leading to an indirect influence on the presence, abundance and distribution of cetaceans. The present study investigated how the effects of environmental cycles impact the habitat use of cetaceans in the Azores. The emerging research questions are: ‘What is the relation between the lunar cycle and the abundance and behaviour of cetaceans in the Azores?’ and ‘What is the relation between the semi-diurnal tidal cycle and the abundance, distribution and behaviour of cetaceans in the Azores?’.