297
intense dolphin watching activities and that negative effects can be minimized if
operators comply with regulations.
While coastal spotted dolphins are found along the Pacific coast, bottlenose dolphins do not showed a continuous in their distribution. For instance, bottlenose
dolphins are rarely observed in the Gulf of Papagayo and surrounding areas, whereas
in the gulfs of Nicoya and Dulce they appear to be more common. In Gulf Dulce
spotted and bottlenose partition the gulf by differences in habitat use and physical
characteristics of the gulf such as bathymetry and topographic characteristics. For
instance, bottlenose dolphins are primarily associated with all major river drainages
at the inner basin and sill area of the gulf, likely representing a key critical habitat
where they main prey is located (Acevedo and Buckhart 1998; Herrera-Miranda
et al. 2016). Dietary information is not available yet, but observations on their feeding behavior suggest bottlenose dolphins feed primarily on demersal fish while
coastal spotted dolphins seem to feed mainly on pelagic fish (Oviedo 2007).
May-Collado et al. (2005) distribution maps indicate that the Gulf of Nicoya is
potentially an important habitat for spotted and bottlenose dolphins. The gulf and
surrounding areas are considered the most important fishing ground in Costa Rica
(Vargas 1995). To put this in perspective, between the two main fishing ports
(located in Puntarenas and Quepos), just in 2014 they accounted for 7511 tons of
fish (including sharks). This is about 62% of total catches in the country for the
same period (INCOPESCA 2016). This high productivity likely explains the regular
presence of spotted and bottlenose dolphins. In addition, other 13 species of cetaceans, including beaked whales, humpback whales, pilot whales, false killer whales,
among others have also been observed in this area (May-Collado et al. 2005;
Martinez-Fernandez et al. 2014). While high species richness may be associated to
food, Palacios-Alfaro pers. comm. (2016) also suggest that the short distance
between coast and continental shelf may also increase the probability of observing
deep water species.
Although the Gulf of Nicoya and surrounding areas represent important habitats
for cetaceans we still know very little about their population dynamics and interactions with human activities in the area. The Central Pacific coast of Costa Rica has
the highest fishing effort in the country, mainly due to artisanal fishing activities that
use of bottom lines and gillnets, purse seine, trawling, and long lines at small and
medium scales. Serious concerns about the potential impact of the fishery industry
in the local cetaceans stems from previous work by Palacios and Gerrodette (1996)
who estimated that the Costa Rican cetacean bycatch in gillnets was considerably
high in comparison with other Central American countries, such as Panama, and by
anecdotal accounts of fisherman witnessing bottlenose dolphin calves being trapped
in sardine nets (Jose D. Palacios Alfaro pers. comm. 2016).
An indirect impact of fisheries is creating dependence for resources. For example, Palacios-Alfaro (2007a, b) found that dolphins can potentially change their
foraging patterns in areas where shrimp fishing occurrence is high. He observed
pantropical spotted dolphins and bottlenose dolphins regularly following trawlers to
feed on the discarded demersal and pelagic fish. Some dolphin groups consistently
12 Ecology and Conservation of Cetaceans of Costa Rica and Panama
intense dolphin watching activities and that negative effects can be minimized if
operators comply with regulations.
While coastal spotted dolphins are found along the Pacific coast, bottlenose dolphins do not showed a continuous in their distribution. For instance, bottlenose
dolphins are rarely observed in the Gulf of Papagayo and surrounding areas, whereas
in the gulfs of Nicoya and Dulce they appear to be more common. In Gulf Dulce
spotted and bottlenose partition the gulf by differences in habitat use and physical
characteristics of the gulf such as bathymetry and topographic characteristics. For
instance, bottlenose dolphins are primarily associated with all major river drainages
at the inner basin and sill area of the gulf, likely representing a key critical habitat
where they main prey is located (Acevedo and Buckhart 1998; Herrera-Miranda
et al. 2016). Dietary information is not available yet, but observations on their feeding behavior suggest bottlenose dolphins feed primarily on demersal fish while
coastal spotted dolphins seem to feed mainly on pelagic fish (Oviedo 2007).
May-Collado et al. (2005) distribution maps indicate that the Gulf of Nicoya is
potentially an important habitat for spotted and bottlenose dolphins. The gulf and
surrounding areas are considered the most important fishing ground in Costa Rica
(Vargas 1995). To put this in perspective, between the two main fishing ports
(located in Puntarenas and Quepos), just in 2014 they accounted for 7511 tons of
fish (including sharks). This is about 62% of total catches in the country for the
same period (INCOPESCA 2016). This high productivity likely explains the regular
presence of spotted and bottlenose dolphins. In addition, other 13 species of cetaceans, including beaked whales, humpback whales, pilot whales, false killer whales,
among others have also been observed in this area (May-Collado et al. 2005;
Martinez-Fernandez et al. 2014). While high species richness may be associated to
food, Palacios-Alfaro pers. comm. (2016) also suggest that the short distance
between coast and continental shelf may also increase the probability of observing
deep water species.
Although the Gulf of Nicoya and surrounding areas represent important habitats
for cetaceans we still know very little about their population dynamics and interactions with human activities in the area. The Central Pacific coast of Costa Rica has
the highest fishing effort in the country, mainly due to artisanal fishing activities that
use of bottom lines and gillnets, purse seine, trawling, and long lines at small and
medium scales. Serious concerns about the potential impact of the fishery industry
in the local cetaceans stems from previous work by Palacios and Gerrodette (1996)
who estimated that the Costa Rican cetacean bycatch in gillnets was considerably
high in comparison with other Central American countries, such as Panama, and by
anecdotal accounts of fisherman witnessing bottlenose dolphin calves being trapped
in sardine nets (Jose D. Palacios Alfaro pers. comm. 2016).
An indirect impact of fisheries is creating dependence for resources. For example, Palacios-Alfaro (2007a, b) found that dolphins can potentially change their
foraging patterns in areas where shrimp fishing occurrence is high. He observed
pantropical spotted dolphins and bottlenose dolphins regularly following trawlers to
feed on the discarded demersal and pelagic fish. Some dolphin groups consistently
12 Ecology and Conservation of Cetaceans of Costa Rica and Panama