Whale-watching tourism is a billion dollar industry that has experienced a constant growth since the 90's. This tourist activity is a two-edged sword. In fact, it often brings money to communities in poor areas of the world and awareness of threatened species but at the same time, it represents a possible disturbance to the same species.

Previous studies have shown how this activity could have an impact on the populations of cetaceans making them change their behaviour. In fact, on different occasions, both dolphins and whales modified several aspects of their behaviour when “disturbed” by Whale-watching vessels such as:

- Increased group cohesion
- Increased group synchrony
- Changes in behavioural state
- Increased dive duration 
- Changes in habitat use 

The aims of this study were:

• Investigate the interaction behaviour with whale-watching boats of different species of cetaceans.
• Investigate the influence of a different number of whale watching vessels on the behaviours of different species of cetaceans.
• Investigate whether a different behavioural state antecedent the observation influences the behaviours of different cetaceans species.