There are 11-12 different cetacean species documented for the Península de Osa area, between 1979-2002, where the most frequently sighted dolphins are spotted dolphins (Stenella attenuata). This species appear to maintain a year-round population in Golfo Dulce, a gulf located 60 km south Drake Bay. Rasmussen et al., were emphatic about the expansion of resorts and tourist activities in Drake Bay (located in Península de Osa) over the last 8 years of their research. The Osa Conservation Area (to which Drake Bay belongs), estimated a total of 88 lodging businesses, from which 48 (55%) are localized along the coast, and own at least one vessel for ecotourism services. These vessels are used permanently, or in an opportunistic way, to offer tourists whale-watch activities, in addition or combined with sport fishing, swim with dolphin, and diving activities. Unfortunately, most of these companies lack proper training and they seem to be creating constant stressful situations to these species.

Several studies have detected changes in cetaceans’ behaviour due to whale-watching: horizontal avoidance, increased dive intervals, increased speed, and vocalizations. Cetaceans’ spatial distribution is influenced by a number of environmental factors, biotic factors and anthropogenic factors, like fishing activity and boat traffic, among others. Special concerns are raised by the sounds of vessels used to approach cetaceans for science and tourism, since they can cause animals to avoid certain areas, effectively reducing or degrading their habitat.