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the state of knowledge of the ecology and conservation status of the cetaceans of
Costa Rica and Panama. Along this line, we describe the consensus of our small
scientific community on what relates to future scientific research and conservation.
The cetacean species richness of Costa Rica and Panama represents about 36% of
the species described worldwide. The dolphin family, Delphinidae is the most
diverse group of cetaceans in these countries, with some species having year-round
resident populations in coastal habitats like the bottlenose dolphins (Tursiops truncatus), the pantropical spotted dolphins (Stenella attenuata), and the Guiana dolphin (Sotalia guianensis). Other dolphin species are found primarily in oceanic and
neritic waters like the rough-toothed dolphins (Steno bredanensis), striped dolphins
(Stenella coeruleoalba), spinner dolphins (S. longirostris), and common dolphins
(Delphinus delphis) (Rodriguez-Fonseca 2001; May-Collado et al. 2005). Among
baleen whales, the humpback whale (Megaptera novaeangliae) is by far the most
common species, and both Costa Rica and Panama possess important habitats used
by these whales during their breeding season (Steiger et al. 1991; Calambokidis
et al. 2000; Rasmussen et al. 2007, 2012).
The economic value of cetaceans in Costa Rica and Panama has increased in the
past 20 years particularly due to whale watching activities, an activity that has
become highly profitable across Latin America (Hoyt and Iñiguez 2008). Profitable
whale watching can mutually benefit humans and wild animal populations, resulting in successful conservation. However, high observation intensities may nevertheless negatively affect animals. In Costa Rica and Panama whale watching is
boat-based, and cetaceans are exposed daily to various levels of engine noise, which
has been shown to elicit avoidance behaviors and stress, and mask important acoustic signals. For example bottlenose dolphins of Bocas del Toro, Panama, are exposed
daily to high levels of underwater noise associated with dolphin-watching boats. In
response, these dolphins modify their communicative signal frequency and duration
presumably to decrease signal masking (e.g., May-Collado and Wartzok 2008,
2015; May-Collado and Quinones-Lebron 2014). Although cetaceans have evolved
ways to compensate for masking by natural ambient noise, noise from human activities represent a new challenge that these animals may not be able to circumvent.
The only option may be to avoid contact with these noises in which case noise acts
R. González-Barrientos • G. Hernández-Mora
Ministerio de Agricultura y Ganadería, Servicio Nacional de Salud Animal (SENASA),
Heredia, Costa Rica
e-mail: cristyrocio@gmail.com; gabbytica@gmail.com
D.M. Palacios
Marine Mammal Institute and Department of Fisheries and Wildlife, Oregon State University,
Corvallis, OR, USA
e-mail: daniel.palacios@oregonstate.edu
J.D. Palacios-Alfaro
Fundacion Keto, San Jose, Costa Rica
e-mail: pala1611@gmail.com
L.J. May-Collado et al.
the state of knowledge of the ecology and conservation status of the cetaceans of
Costa Rica and Panama. Along this line, we describe the consensus of our small
scientific community on what relates to future scientific research and conservation.
The cetacean species richness of Costa Rica and Panama represents about 36% of
the species described worldwide. The dolphin family, Delphinidae is the most
diverse group of cetaceans in these countries, with some species having year-round
resident populations in coastal habitats like the bottlenose dolphins (Tursiops truncatus), the pantropical spotted dolphins (Stenella attenuata), and the Guiana dolphin (Sotalia guianensis). Other dolphin species are found primarily in oceanic and
neritic waters like the rough-toothed dolphins (Steno bredanensis), striped dolphins
(Stenella coeruleoalba), spinner dolphins (S. longirostris), and common dolphins
(Delphinus delphis) (Rodriguez-Fonseca 2001; May-Collado et al. 2005). Among
baleen whales, the humpback whale (Megaptera novaeangliae) is by far the most
common species, and both Costa Rica and Panama possess important habitats used
by these whales during their breeding season (Steiger et al. 1991; Calambokidis
et al. 2000; Rasmussen et al. 2007, 2012).
The economic value of cetaceans in Costa Rica and Panama has increased in the
past 20 years particularly due to whale watching activities, an activity that has
become highly profitable across Latin America (Hoyt and Iñiguez 2008). Profitable
whale watching can mutually benefit humans and wild animal populations, resulting in successful conservation. However, high observation intensities may nevertheless negatively affect animals. In Costa Rica and Panama whale watching is
boat-based, and cetaceans are exposed daily to various levels of engine noise, which
has been shown to elicit avoidance behaviors and stress, and mask important acoustic signals. For example bottlenose dolphins of Bocas del Toro, Panama, are exposed
daily to high levels of underwater noise associated with dolphin-watching boats. In
response, these dolphins modify their communicative signal frequency and duration
presumably to decrease signal masking (e.g., May-Collado and Wartzok 2008,
2015; May-Collado and Quinones-Lebron 2014). Although cetaceans have evolved
ways to compensate for masking by natural ambient noise, noise from human activities represent a new challenge that these animals may not be able to circumvent.
The only option may be to avoid contact with these noises in which case noise acts
R. González-Barrientos • G. Hernández-Mora
Ministerio de Agricultura y Ganadería, Servicio Nacional de Salud Animal (SENASA),
Heredia, Costa Rica
e-mail: cristyrocio@gmail.com; gabbytica@gmail.com
D.M. Palacios
Marine Mammal Institute and Department of Fisheries and Wildlife, Oregon State University,
Corvallis, OR, USA
e-mail: daniel.palacios@oregonstate.edu
J.D. Palacios-Alfaro
Fundacion Keto, San Jose, Costa Rica
e-mail: pala1611@gmail.com
L.J. May-Collado et al.