298
approached trawlers and followed them for up to 11 h, suggesting that at least some
dolphins might have develop a dependency on this resource.
The third most common cetacean in the Pacific coast of Costa Rica is the humpback whale. Humpback whales make seasonal migrations from high-latitude feeding grounds to low latitude breeding areas where whales give birth and mate. Costa
Rica receives humpback whales from two main feeding grounds: off CaliforniaOregon- Washington in the Eastern North Pacific (northern whales) between
December and April (Steiger et al. 1991; Acevedo and Smultea 1995; Calambokidis
et al. 2000; Rasmussen et al. 2012) and off Chile and Antarctica between July to
November (Acevedo et al. 2007; Rasmussen et al. 2007).
Southern humpback whales have been previously documented off the Pacific
coast of Central America during the austral wintering season (Townsend 1935;
Acevedo and Smultea 1995; Florez-González et al. 1998; Rasmussen et al. 2007;
Best 2008). Central America is unique because it harbors the northernmost breeding
area of any southern hemisphere humpback whale population, with whales migrating approximately 8300 km from the feeding areas (Acevedo et al. 2007; Rasmussen
et al. 2007). As mentioned before these whales have been linked to feeding areas off
Chile and Antarctica (Acevedo et al. 2007; Rasmussen et al. 2007) as well as to
adjacent breeding areas off Colombia (Florez-González et al. 1998), and are part of
the IWC-designated “Breeding Stock G” (BSG). In Panama, one of the most studied
breeding grounds for southern humpback whales is the Gulf of Chiriquí. This gulf
lies in the western part of Panama, and is bordered by the Azuero Peninsula to the
east, and Punta Burica to the west. Here, humpback whales are frequently sighted,
predominantly in shallow waters near island groups and close to shore. Approximately
half of the sightings contained calves, many of which were small in size, suggesting
the females are calving in these waters or in waters very close by. Similar patterns
are found in Costa Rica, where 64% of the sightings between Caño Island and
Drake Bay are mothers with calves (Palacios-Alfaro et al. 2014) (Figs. 12.1, 12.2,
12.3, 12.4, 12.5, 12.6, 12.7, 12.8, 12.9, 12.10, 12.11, 12.12, 12.13, 12.14).
Although, research on humpbacks whales in Costa Rica was initially focused on
northern whales, over the last years a perceived decrease in the number of these
whales is raising concerns among local scientists. For this reason whale-watching
activities are now only targeted towards southern whales. According to the National
Oceanographic Atmospheric Administration (NOAA) while most humpback whale
populations are recovering, the Central American humpback whales remain endangered. Therefore, future research should focus on determining if the number of
northern whales breeding in Costa Rica is indeed decreasing, and if so what are the
factors responsible for this decrease.
The Gulf of Chiriqui is also an important habitat for six other species of cetacean. The most common dolphin is the spotted dolphin both in number of sightings
and abundance, followed by bottlenose dolphins, which are sighted both in estuarine waters and offshore waters near islands. Bryde’s whales (Balaenoptera edeni)
are seen occasionally near the Islas Contreras and the Islas Secas. Less common are
false killer whales (Pseudorca crassidens), sighted twice near the Islas Secas; one
L.J. May-Collado et al.
approached trawlers and followed them for up to 11 h, suggesting that at least some
dolphins might have develop a dependency on this resource.
The third most common cetacean in the Pacific coast of Costa Rica is the humpback whale. Humpback whales make seasonal migrations from high-latitude feeding grounds to low latitude breeding areas where whales give birth and mate. Costa
Rica receives humpback whales from two main feeding grounds: off CaliforniaOregon- Washington in the Eastern North Pacific (northern whales) between
December and April (Steiger et al. 1991; Acevedo and Smultea 1995; Calambokidis
et al. 2000; Rasmussen et al. 2012) and off Chile and Antarctica between July to
November (Acevedo et al. 2007; Rasmussen et al. 2007).
Southern humpback whales have been previously documented off the Pacific
coast of Central America during the austral wintering season (Townsend 1935;
Acevedo and Smultea 1995; Florez-González et al. 1998; Rasmussen et al. 2007;
Best 2008). Central America is unique because it harbors the northernmost breeding
area of any southern hemisphere humpback whale population, with whales migrating approximately 8300 km from the feeding areas (Acevedo et al. 2007; Rasmussen
et al. 2007). As mentioned before these whales have been linked to feeding areas off
Chile and Antarctica (Acevedo et al. 2007; Rasmussen et al. 2007) as well as to
adjacent breeding areas off Colombia (Florez-González et al. 1998), and are part of
the IWC-designated “Breeding Stock G” (BSG). In Panama, one of the most studied
breeding grounds for southern humpback whales is the Gulf of Chiriquí. This gulf
lies in the western part of Panama, and is bordered by the Azuero Peninsula to the
east, and Punta Burica to the west. Here, humpback whales are frequently sighted,
predominantly in shallow waters near island groups and close to shore. Approximately
half of the sightings contained calves, many of which were small in size, suggesting
the females are calving in these waters or in waters very close by. Similar patterns
are found in Costa Rica, where 64% of the sightings between Caño Island and
Drake Bay are mothers with calves (Palacios-Alfaro et al. 2014) (Figs. 12.1, 12.2,
12.3, 12.4, 12.5, 12.6, 12.7, 12.8, 12.9, 12.10, 12.11, 12.12, 12.13, 12.14).
Although, research on humpbacks whales in Costa Rica was initially focused on
northern whales, over the last years a perceived decrease in the number of these
whales is raising concerns among local scientists. For this reason whale-watching
activities are now only targeted towards southern whales. According to the National
Oceanographic Atmospheric Administration (NOAA) while most humpback whale
populations are recovering, the Central American humpback whales remain endangered. Therefore, future research should focus on determining if the number of
northern whales breeding in Costa Rica is indeed decreasing, and if so what are the
factors responsible for this decrease.
The Gulf of Chiriqui is also an important habitat for six other species of cetacean. The most common dolphin is the spotted dolphin both in number of sightings
and abundance, followed by bottlenose dolphins, which are sighted both in estuarine waters and offshore waters near islands. Bryde’s whales (Balaenoptera edeni)
are seen occasionally near the Islas Contreras and the Islas Secas. Less common are
false killer whales (Pseudorca crassidens), sighted twice near the Islas Secas; one
L.J. May-Collado et al.