Juan Diego Pacheco-Polanco - Academia.edu (original) (raw)
Papers by Juan Diego Pacheco-Polanco
Revista de Biología Tropical
Introduction: The coastal form of pantropical spotted dolphins (Stenella attenuata graffmani) is ... more Introduction: The coastal form of pantropical spotted dolphins (Stenella attenuata graffmani) is commonly found along the Pacific coast of Costa Rica. Within Golfo Dulce, a fiord-like-embayment bordering the Osa Peninsula, pantropical spotted dolphins are sympatric with inshore bottlenose dolphins (Tursiops truncatus) and these marine predators provide an important source of revenue for local communities through boat-based tours. Objective: Here we estimated the population size and demographic parameters of the coastal pantropical spotted dolphins in Golfo Dulce. Methods: The study area was surveyed using non-random boat surveys. Upon encounter, dolphins were individually photo-identified using natural marks in their dorsal fins to estimate population abundance and survival using three emigration scenarios. Results: A total of 280 dolphins were photoidentified, 65 % of which were observed only once. A total of 30 models were produced, and only two were considered to be parsimonious....
Revista de Biología Tropical
Introduction: Lobomycosis, is a chronic mycotic disease of the skin and sub-dermal tissue caused ... more Introduction: Lobomycosis, is a chronic mycotic disease of the skin and sub-dermal tissue caused by Paracoccidioides ceti, which affects dolphins worldwide. In Costa Rica, the incidence of lobomycosis Like Disease (LLD) has been documented in inshore common bottlenose dolphins (Tursiops truncatus) from the waters of Golfo Dulce, South Pacific. Objective: Examine the prevalence pattern of LLD in inshore T. truncatus from Costa Rica Pacific waters, specifically in Golfo Dulce and Golfo de Nicoya. Methods: We examined over 20 000 photographs of T. truncatus, collected during long-term research on cetaceans in 2005-2020 (n = 476 surveys), in Golfo Dulce, as well of nine sightings T. truncatus from the Golfo de Nicoya , obtained during 17 samplings events in 2014-2022, these records for the presence of LLD allowed to calculate the prevalence rate with a confidence interval. Results: The prevalence rate of LLD in adult photo-identified individuals was 13.1 % (CI: 12 -14.2) in Golfo Dulce...
El Golfo Dulce resguarda una población residente de delfines nariz de botella (T. truncatus), así... more El Golfo Dulce resguarda una población residente de delfines nariz de botella (T. truncatus), así como poblaciones migratorias de ballenas jorobadas (M. novaeangliae, poblaciones Pacífico Norte y Sur). Este estudio ofrece un análisis espacial de la distribución de uso de delfines nariz de botella (2005-2014: n= 407) y ballenas jorobadas (2010-2014: n= 167), valorando los impactos potenciales del desarrollo costero, por un proyecto de marina, al solaparse con hábitats críticos de las especies en estudio. Registros con información espacial y de conducta fueron evaluados mediante: 1) el índice promedio del vecino más cercano y 2) estimados de densidad kernel, con dos contornos de distribución de uso, 50% para las áreas núcleo críticas y 95% para el ámbito hogar potencial. Agregaciones no azarosas de delfines nariz de botella (KDE-adaptativo: Densidad 21.36 registros/km2; H=0.25; H-REF= 0.49), se asociaron a todas las desembocaduras de ríos mayores en la cuenca interna y del área del umbral del Golfo Dulce, lo que representa un hábitat crítico de alimentación. Agregaciones no azarosas de ballenas jorobadas, incluyendo pares madre-cría (KDE-adaptativo: Densidad 1.33 registros/km2; H=0.25; H-REF= 0.49), usarían la costa oeste del área del umbral como hábitat crítico de reproducción-cría, adicionalmente, ballenas cantando se agregaron en un área discreta del centro del umbral. Los resultados sugieren que la construcción de una marina en el Golfo tiene el potencial de afectar negativamente los hábitats críticos de ambas especies, al convertirse en una fuente importante de impactos antropogénicos por el incremento del tráfico marítimo y la contaminación sónica asociada.
Revista Ciencias Marinas y Costeras, 2011
Este estudio trata sobre la distribución espacial de depredadores marinos topes, particularmente ... more Este estudio trata sobre la distribución espacial de depredadores marinos topes, particularmente cetáceos odontocetos y misticetos migratorios. Se describe el riesgo potencial de afectación por el establecimiento de instalaciones asociadas con operaciones locales de maricultura: jaulas de engorde para atún. Por medio de un enfoque teórico y empírico se establece cuantitativamente como la profundidad máxima, un factor limitante en la distribución y definición del nicho ecológico de cetáceos, se solaparía en valores con el área propuesta para el establecimiento de las jaulas, lo que induciría dos escenarios probables de afectación: el desplazamiento de las poblaciones de depredadores de un hábitat-nicho de alimentación potencial y la interacción progresiva entre los depredadores con la fauna acompañante alrededor de las instalaciones de la operación de cultivo, lo anterior implicaría un riesgo perenne de captura incidental de dichos depredadores. Adicionalmente, la presencia de ballen...
Frontiers in Marine Science
Warming events in the Pacific Ocean are becoming more frequent, intense, and on a larger temporal... more Warming events in the Pacific Ocean are becoming more frequent, intense, and on a larger temporal and spatial scale. This has caused critical habitats of marine species to lose their quality and marine organisms respond by modifying their critical feeding and reproduction behaviors, as well as their distribution. The Northeast Pacific humpback whale of the Central America distinct population segment (DPS) remains Endangered due to its small population size and because its response to climate change and human interventions is unknown. In this work, we showed the encounter rates of humpback whales in their breeding grounds in Costa Rica for breeding seasons comprised in the period 2000-2020. We analyze the influence of climatic indices that influence the Pacific and environmental variables related to temperature and productivity in the feeding grounds of this population (United States). We hypothesize that the more intense the warming events, the fewer humpback whales complete their m...
ABSTRACT Humpback whales (Megaptera novaeangliae) aggregate in winter breeding and calving ground... more ABSTRACT Humpback whales (Megaptera novaeangliae) aggregate in winter breeding and calving grounds along continental margins, coastal islands, or archipelagos located in tropical waters. Migration to these breeding sites requires a long journey from northern feeding areas in temperate and circumpolar latitudes. The humpback whales habitat preference is generally restricted to coastal areas, and their tendency to concentrate in specific locations to reproduce exposes them to anthropogenic threats such as fishing, coastal development, water pollution, and marine traffic. There has been an increasing interest for coastal development projects that intent to capitalize the natural attributes of Golfo Dulce, in the southern Pacific coast of Costa Rica, potentially threatening the stability of the ecosystem and creating habitat disruption for the wintering population of humpback whales in the area. This contributions focalize in important ecological aspect related with areas use, particularly behavioral elements associated with the spatial aggregation of competitive groups, mother – calf pairs and vocalizing humpback whales. We identify areas with significant aggregation of mother-calf pairs that can be categorized as critical nursing areas, producing key baseline information to promote effective conservation and management strategies such as Marine Spatial Planning.
Revista De Biologia Tropical, 2020
Introduction: False killer whale (Pseudorca crassidens) is a tropical and subtropical social spec... more Introduction: False killer whale (Pseudorca crassidens) is a tropical and subtropical social species that live in groups with individuals of mixed ages and sex classes. False killer whales have been documented since the late 1990s in Southwestern Costa Rica. Objective: To estimate the abundance of false killer whales in Osa Peninsula waters. Methods: Cetacean surveys off the Osa Peninsula Waters (OPW), Costa Rica, yielded opportunistic encounters with false killer whales in Drake Bay and Caño Island (2001-2019) and observations during formal surveys in Golfo Dulce (2005-2015). Photo-identification data was analyzed using capture-markrecapture models in the study area, through an open population (POPAN) framework, considering the effect of time on the parameters apparent survival and capture probability, producing an abundance estimate for a superpopulation in the entire study area. Results: False killer whale abundance in OPW is characterized by a small population size of no more th...
Revista De Biologia Tropical, 2015
Diversity of cetaceans in coastal seascape Golfo Dulce, Osa Peninsula, Costa Rica. Golfo Dulce is... more Diversity of cetaceans in coastal seascape Golfo Dulce, Osa Peninsula, Costa Rica. Golfo Dulce is a fiord-lilke embayment located in the southern Pacific of Costa Rica, this coastal-marine ecosystem harbors an important wealth in marine biodiversity, including cetaceans. In this study we describe the cetacean commu- nity of Golfo Dulce, in relation to the diversity of habitats constituting the seascape. Sighting data collected in periodic systematic surveys has yielded 943 records (2005-2014≈3 490h≈64 533km), of 12 species of cetaceans. A gradient of cetacean diversity is observed from the inner basin to the transitional-oceanic area at the entrance of the Gulf, with coastal bottlenose dolphin and spotted dolphin dominating the inner basin, and bottlenose dolphins and migratory humpback whales the sill area. Transitional oceanic habitat holds the greatest species diversity dominated by oceanic species, particularly piscivorous delphinids, including the off-shore form of bottlenose d...
IWC Journal of Cetacean Research and Management
The aim of this assessment is to advance our understanding in the spatial ecology of the resident... more The aim of this assessment is to advance our understanding in the spatial ecology of the resident inshore and offshore population of bottlenosedolphins in Golfo Dulce (GD) and Osa Peninsula Waters (OPW). Our approach used niche-based models (Phillips et al., 2006, Thorne et al., 2012,Friedlaender et al., 2011), which provided details of how dolphins use coastal and oceanic habitats, describing the factors that influence theirdistribution in the study area and identifying the critical habitats to be considered for management and conservation. Our analyses indicate severalimportant aspects of the distribution of these two ecotypes of bottlenose dolphins. As expected in the study area, these two ecological races occurin close proximity, but differ in the structural factors of the habitat they occupy. The inshore population uses areas close to the mouths of the riversas critical foraging habitats, being influenced by tidal cycles and seasonal changes in water temperature and salinity. T...
Revista de Biología Tropical
El tiburón ballena (Rhincodon typus), es el condrictio viviente más grande del mundo, con una dis... more El tiburón ballena (Rhincodon typus), es el condrictio viviente más grande del mundo, con una distribución cosmopolita, encontrándose tanto en mares tropicales como subtropicales. La Unión Mundial para la Conservación (IUCN) lo clasifico como vulnerable y con una tendencia poblacional en disminución, conocido por realizar grandes agregaciones alrededor del mundo, relacionadas a procesos oceanográficos que incrementan la productividad primaria del ambiente marino. Por primera vez, se reporta cuatro eventos de alimentación de tiburón ballena dentro de la cuenca interna de Golfo Dulce, un fiordo tropical ubicado en la costa del Pacífico Sur de Costa Rica. Los avistamientos fueron realizados en enero y agosto del 2009, marzo 2012 y enero del 2013, donde la estructura y tamaño de los grupos se mantuvo constante en el tiempo encontrándose una proporción similar de adultos y juveniles. Estas agregaciones fueron observadas en la costa occidental de Golfo Dulce en un área que abarcaba los 23...
Revista Ciencias Marinas y Costeras, 2015
Revista de biologia tropical
Whale shark, Rhincodon typus (Orectolobifoms: Rhincodontidae) feeding aggregations in Golfo Dulce... more Whale shark, Rhincodon typus (Orectolobifoms: Rhincodontidae) feeding aggregations in Golfo Dulce, Osa Peninsula, Costa Rica. The zooplanktivorous whale shark (Rhincodon typus), is the largest living chondrichthyan and a cosmopolitan species, living in tropical, warm and temperate waters. It is considered vulnerable by the International Union for Conservation of Nature (IUCN), and is known for big aggregations in many parts of the world. These are associated with particular oceanographic features where primary productivity is thought to be high. For the first time, four whale shark feeding aggregations are documented in Golfo Dulce, Costa Rica, a tropical fjord-like embayment located in the south Pacific region of the country. structure and size remained constant over time with an equal proportion of adults and juveniles in the same area. These aggrega-tions were observed on the northwestern coast of Golfo Dulce's inner basin, close to the Rincón and Tigre rivers. These two rive...
The bottlenose dolphins (Tursiops truncatus) is the second most commonly encountered odontocete o... more The bottlenose dolphins (Tursiops truncatus) is the second most commonly encountered odontocete off the southern Pacific coast of Costa Rica, after the coastal pantropical spotted dolphin (Stenella attenuata graffmani). The species occurs beyond the 200 m isobath off Osa Peninsula, with frequent incursions to coastal waters. Bottlenose dolphins are also frequently sighted within inshore habitats of Golfo Dulce. This study examines the spatial distribution pattern of both ecotypes by analyzing the sighting records and relative density of bottlenose dolphins in two sub-areas: off Osa Peninsula (2001 -2006, n= 238) and Golfo Dulce (2005 -2011, n= 172). Kernel distribution maps were produced and the spatial distribution pattern quantified by means of the near neighbor index. Based on the external morphology of the animals seen and their off-shore / in-shore occurrence, we conclude that all records off Osa peninsula represent the oceanic ecotype (primarily off-shore sightings), whereas t...
Revista de biologia tropical
Diversity of cetaceans in coastal seascape Golfo Dulce, Osa Peninsula, Costa Rica. Golfo Dulce is... more Diversity of cetaceans in coastal seascape Golfo Dulce, Osa Peninsula, Costa Rica. Golfo Dulce is a fiord-lilke embayment located in the southern Pacific of Costa Rica, this coastal-marine ecosystem harbors an important wealth in marine biodiversity, including cetaceans. In this study we describe the cetacean community of Golfo Dulce, in relation to the diversity of habitats constituting the seascape. Sighting data collected in periodic systematic surveys has yielded 943 records (2005-2014≈3 490h≈64 533km), of 12 species of cetaceans. A gradient of cetacean diversity is observed from the inner basin to the transitional-oceanic area at the entrance of the Gulf, with coastal bottlenose dolphin and spotted dolphin dominating the inner basin, and bottlenose dolphins and migratory humpback whales the sill area. Transitional oceanic habitat holds the greatest species diversity dominated by oceanic species, particularly piscivorous delphinids, including the offshore form of bottlenose dolp...
Diseases of aquatic organisms, Jan 16, 2014
Lacaziosis (also known as lobomycosis) is a chronic dermal disease caused by the fungal agent Lac... more Lacaziosis (also known as lobomycosis) is a chronic dermal disease caused by the fungal agent Lacazia loboi, which affects both humans and dolphins. Photographic data have been used to identify lacaziosis-like disease (LLD) among dolphins in the waters of North and South America, and here we report LLD in bottlenose dolphins Tursiops truncatus off the coast of Costa Rica, the first reporting in Central American waters. During the periods of 1991 to 1992 and 2010 to 2011, 3 research teams conducted separate dolphin surveys in the Pacific tropical fiord Golfo Dulce, and each documented skin lesions in the resident population of bottlenose dolphins. Photo-ID records were used to identify LLD-affected bottlenose dolphins and to assess their lesions. Findings showed between 13.2 and 16.1% of the identified dolphins exhibited lesions grossly resembling lacaziosis. By combining efforts and cross-referencing photographic data, the teams explored the presence of LLD in Golfo Dulce over a time gap of approximately 20 yr. Our findings expand the geographical range of the disease and offer insight into its longevity within a given population of dolphins.
The identification of critical habitats for cetaceans is the foundation in the design and impleme... more The identification of critical habitats for cetaceans is the foundation in the design and implementation of Marine Spatial Planning, including the creation of Marine Protected Areas, associated with local cetacean fauna. Golfo Dulce is a tropical fjord-like embayment located in the southern Pacific coast of Costa Rica; it is among the best preserved marine habitats in the Osa Peninsula ecosystem. Baseline data on cetacean occurrence have been gathered in this region since 2005, focusing primarily on two sympatric populations of coastal delphinids, the pantropical spotted dolphin (Stenella attenuata graffmani) and bottlenose dolphin (Tursiops truncatus). The current study investigates the underlying behavioral mechanisms that govern patterns of niche differentiation and the resulting conservation implications. We focus on the foraging areas/habitats of high conservation importance due to the role they play in the day-to-day needs of the two dolphin species in their year-round presence in the inner basin of Golfo Dulce.
Humpback whales (Megaptera novaeangliae) aggregate in winter breeding and calving grounds along c... more Humpback whales (Megaptera novaeangliae) aggregate in winter breeding and calving grounds along continental margins, coastal islands, or archipelagos located in tropical waters. Migration to these breeding sites requires a long journey from northern feeding areas in temperate and circumpolar latitudes. The humpback whales habitat preference is generally restricted to coastal areas, and their tendency to concentrate in specific locations to reproduce exposes them to anthropogenic threats such as fishing, coastal development, water pollution, and marine traffic. There has been an increasing interest for coastal development projects that intent to capitalize the natural attributes of Golfo Dulce, in the southern Pacific coast of Costa Rica, potentially threatening the stability of the ecosystem and creating habitat disruption for the wintering population of humpback whales in the area. This contributions focalize in important ecological aspect related with areas use, particularly behavioral elements associated with the spatial aggregation of competitive groups, mother – calf pairs and vocalizing humpback whales. We identify areas with significant aggregation of mother- calf pairs that can be categorized as critical nursing areas, producing key baseline information to promote effective conservation and management strategies such as Marine Spatial Planning.
Revista de Biología Tropical
Introduction: The coastal form of pantropical spotted dolphins (Stenella attenuata graffmani) is ... more Introduction: The coastal form of pantropical spotted dolphins (Stenella attenuata graffmani) is commonly found along the Pacific coast of Costa Rica. Within Golfo Dulce, a fiord-like-embayment bordering the Osa Peninsula, pantropical spotted dolphins are sympatric with inshore bottlenose dolphins (Tursiops truncatus) and these marine predators provide an important source of revenue for local communities through boat-based tours. Objective: Here we estimated the population size and demographic parameters of the coastal pantropical spotted dolphins in Golfo Dulce. Methods: The study area was surveyed using non-random boat surveys. Upon encounter, dolphins were individually photo-identified using natural marks in their dorsal fins to estimate population abundance and survival using three emigration scenarios. Results: A total of 280 dolphins were photoidentified, 65 % of which were observed only once. A total of 30 models were produced, and only two were considered to be parsimonious....
Revista de Biología Tropical
Introduction: Lobomycosis, is a chronic mycotic disease of the skin and sub-dermal tissue caused ... more Introduction: Lobomycosis, is a chronic mycotic disease of the skin and sub-dermal tissue caused by Paracoccidioides ceti, which affects dolphins worldwide. In Costa Rica, the incidence of lobomycosis Like Disease (LLD) has been documented in inshore common bottlenose dolphins (Tursiops truncatus) from the waters of Golfo Dulce, South Pacific. Objective: Examine the prevalence pattern of LLD in inshore T. truncatus from Costa Rica Pacific waters, specifically in Golfo Dulce and Golfo de Nicoya. Methods: We examined over 20 000 photographs of T. truncatus, collected during long-term research on cetaceans in 2005-2020 (n = 476 surveys), in Golfo Dulce, as well of nine sightings T. truncatus from the Golfo de Nicoya , obtained during 17 samplings events in 2014-2022, these records for the presence of LLD allowed to calculate the prevalence rate with a confidence interval. Results: The prevalence rate of LLD in adult photo-identified individuals was 13.1 % (CI: 12 -14.2) in Golfo Dulce...
El Golfo Dulce resguarda una población residente de delfines nariz de botella (T. truncatus), así... more El Golfo Dulce resguarda una población residente de delfines nariz de botella (T. truncatus), así como poblaciones migratorias de ballenas jorobadas (M. novaeangliae, poblaciones Pacífico Norte y Sur). Este estudio ofrece un análisis espacial de la distribución de uso de delfines nariz de botella (2005-2014: n= 407) y ballenas jorobadas (2010-2014: n= 167), valorando los impactos potenciales del desarrollo costero, por un proyecto de marina, al solaparse con hábitats críticos de las especies en estudio. Registros con información espacial y de conducta fueron evaluados mediante: 1) el índice promedio del vecino más cercano y 2) estimados de densidad kernel, con dos contornos de distribución de uso, 50% para las áreas núcleo críticas y 95% para el ámbito hogar potencial. Agregaciones no azarosas de delfines nariz de botella (KDE-adaptativo: Densidad 21.36 registros/km2; H=0.25; H-REF= 0.49), se asociaron a todas las desembocaduras de ríos mayores en la cuenca interna y del área del umbral del Golfo Dulce, lo que representa un hábitat crítico de alimentación. Agregaciones no azarosas de ballenas jorobadas, incluyendo pares madre-cría (KDE-adaptativo: Densidad 1.33 registros/km2; H=0.25; H-REF= 0.49), usarían la costa oeste del área del umbral como hábitat crítico de reproducción-cría, adicionalmente, ballenas cantando se agregaron en un área discreta del centro del umbral. Los resultados sugieren que la construcción de una marina en el Golfo tiene el potencial de afectar negativamente los hábitats críticos de ambas especies, al convertirse en una fuente importante de impactos antropogénicos por el incremento del tráfico marítimo y la contaminación sónica asociada.
Revista Ciencias Marinas y Costeras, 2011
Este estudio trata sobre la distribución espacial de depredadores marinos topes, particularmente ... more Este estudio trata sobre la distribución espacial de depredadores marinos topes, particularmente cetáceos odontocetos y misticetos migratorios. Se describe el riesgo potencial de afectación por el establecimiento de instalaciones asociadas con operaciones locales de maricultura: jaulas de engorde para atún. Por medio de un enfoque teórico y empírico se establece cuantitativamente como la profundidad máxima, un factor limitante en la distribución y definición del nicho ecológico de cetáceos, se solaparía en valores con el área propuesta para el establecimiento de las jaulas, lo que induciría dos escenarios probables de afectación: el desplazamiento de las poblaciones de depredadores de un hábitat-nicho de alimentación potencial y la interacción progresiva entre los depredadores con la fauna acompañante alrededor de las instalaciones de la operación de cultivo, lo anterior implicaría un riesgo perenne de captura incidental de dichos depredadores. Adicionalmente, la presencia de ballen...
Frontiers in Marine Science
Warming events in the Pacific Ocean are becoming more frequent, intense, and on a larger temporal... more Warming events in the Pacific Ocean are becoming more frequent, intense, and on a larger temporal and spatial scale. This has caused critical habitats of marine species to lose their quality and marine organisms respond by modifying their critical feeding and reproduction behaviors, as well as their distribution. The Northeast Pacific humpback whale of the Central America distinct population segment (DPS) remains Endangered due to its small population size and because its response to climate change and human interventions is unknown. In this work, we showed the encounter rates of humpback whales in their breeding grounds in Costa Rica for breeding seasons comprised in the period 2000-2020. We analyze the influence of climatic indices that influence the Pacific and environmental variables related to temperature and productivity in the feeding grounds of this population (United States). We hypothesize that the more intense the warming events, the fewer humpback whales complete their m...
ABSTRACT Humpback whales (Megaptera novaeangliae) aggregate in winter breeding and calving ground... more ABSTRACT Humpback whales (Megaptera novaeangliae) aggregate in winter breeding and calving grounds along continental margins, coastal islands, or archipelagos located in tropical waters. Migration to these breeding sites requires a long journey from northern feeding areas in temperate and circumpolar latitudes. The humpback whales habitat preference is generally restricted to coastal areas, and their tendency to concentrate in specific locations to reproduce exposes them to anthropogenic threats such as fishing, coastal development, water pollution, and marine traffic. There has been an increasing interest for coastal development projects that intent to capitalize the natural attributes of Golfo Dulce, in the southern Pacific coast of Costa Rica, potentially threatening the stability of the ecosystem and creating habitat disruption for the wintering population of humpback whales in the area. This contributions focalize in important ecological aspect related with areas use, particularly behavioral elements associated with the spatial aggregation of competitive groups, mother – calf pairs and vocalizing humpback whales. We identify areas with significant aggregation of mother-calf pairs that can be categorized as critical nursing areas, producing key baseline information to promote effective conservation and management strategies such as Marine Spatial Planning.
Revista De Biologia Tropical, 2020
Introduction: False killer whale (Pseudorca crassidens) is a tropical and subtropical social spec... more Introduction: False killer whale (Pseudorca crassidens) is a tropical and subtropical social species that live in groups with individuals of mixed ages and sex classes. False killer whales have been documented since the late 1990s in Southwestern Costa Rica. Objective: To estimate the abundance of false killer whales in Osa Peninsula waters. Methods: Cetacean surveys off the Osa Peninsula Waters (OPW), Costa Rica, yielded opportunistic encounters with false killer whales in Drake Bay and Caño Island (2001-2019) and observations during formal surveys in Golfo Dulce (2005-2015). Photo-identification data was analyzed using capture-markrecapture models in the study area, through an open population (POPAN) framework, considering the effect of time on the parameters apparent survival and capture probability, producing an abundance estimate for a superpopulation in the entire study area. Results: False killer whale abundance in OPW is characterized by a small population size of no more th...
Revista De Biologia Tropical, 2015
Diversity of cetaceans in coastal seascape Golfo Dulce, Osa Peninsula, Costa Rica. Golfo Dulce is... more Diversity of cetaceans in coastal seascape Golfo Dulce, Osa Peninsula, Costa Rica. Golfo Dulce is a fiord-lilke embayment located in the southern Pacific of Costa Rica, this coastal-marine ecosystem harbors an important wealth in marine biodiversity, including cetaceans. In this study we describe the cetacean commu- nity of Golfo Dulce, in relation to the diversity of habitats constituting the seascape. Sighting data collected in periodic systematic surveys has yielded 943 records (2005-2014≈3 490h≈64 533km), of 12 species of cetaceans. A gradient of cetacean diversity is observed from the inner basin to the transitional-oceanic area at the entrance of the Gulf, with coastal bottlenose dolphin and spotted dolphin dominating the inner basin, and bottlenose dolphins and migratory humpback whales the sill area. Transitional oceanic habitat holds the greatest species diversity dominated by oceanic species, particularly piscivorous delphinids, including the off-shore form of bottlenose d...
IWC Journal of Cetacean Research and Management
The aim of this assessment is to advance our understanding in the spatial ecology of the resident... more The aim of this assessment is to advance our understanding in the spatial ecology of the resident inshore and offshore population of bottlenosedolphins in Golfo Dulce (GD) and Osa Peninsula Waters (OPW). Our approach used niche-based models (Phillips et al., 2006, Thorne et al., 2012,Friedlaender et al., 2011), which provided details of how dolphins use coastal and oceanic habitats, describing the factors that influence theirdistribution in the study area and identifying the critical habitats to be considered for management and conservation. Our analyses indicate severalimportant aspects of the distribution of these two ecotypes of bottlenose dolphins. As expected in the study area, these two ecological races occurin close proximity, but differ in the structural factors of the habitat they occupy. The inshore population uses areas close to the mouths of the riversas critical foraging habitats, being influenced by tidal cycles and seasonal changes in water temperature and salinity. T...
Revista de Biología Tropical
El tiburón ballena (Rhincodon typus), es el condrictio viviente más grande del mundo, con una dis... more El tiburón ballena (Rhincodon typus), es el condrictio viviente más grande del mundo, con una distribución cosmopolita, encontrándose tanto en mares tropicales como subtropicales. La Unión Mundial para la Conservación (IUCN) lo clasifico como vulnerable y con una tendencia poblacional en disminución, conocido por realizar grandes agregaciones alrededor del mundo, relacionadas a procesos oceanográficos que incrementan la productividad primaria del ambiente marino. Por primera vez, se reporta cuatro eventos de alimentación de tiburón ballena dentro de la cuenca interna de Golfo Dulce, un fiordo tropical ubicado en la costa del Pacífico Sur de Costa Rica. Los avistamientos fueron realizados en enero y agosto del 2009, marzo 2012 y enero del 2013, donde la estructura y tamaño de los grupos se mantuvo constante en el tiempo encontrándose una proporción similar de adultos y juveniles. Estas agregaciones fueron observadas en la costa occidental de Golfo Dulce en un área que abarcaba los 23...
Revista Ciencias Marinas y Costeras, 2015
Revista de biologia tropical
Whale shark, Rhincodon typus (Orectolobifoms: Rhincodontidae) feeding aggregations in Golfo Dulce... more Whale shark, Rhincodon typus (Orectolobifoms: Rhincodontidae) feeding aggregations in Golfo Dulce, Osa Peninsula, Costa Rica. The zooplanktivorous whale shark (Rhincodon typus), is the largest living chondrichthyan and a cosmopolitan species, living in tropical, warm and temperate waters. It is considered vulnerable by the International Union for Conservation of Nature (IUCN), and is known for big aggregations in many parts of the world. These are associated with particular oceanographic features where primary productivity is thought to be high. For the first time, four whale shark feeding aggregations are documented in Golfo Dulce, Costa Rica, a tropical fjord-like embayment located in the south Pacific region of the country. structure and size remained constant over time with an equal proportion of adults and juveniles in the same area. These aggrega-tions were observed on the northwestern coast of Golfo Dulce's inner basin, close to the Rincón and Tigre rivers. These two rive...
The bottlenose dolphins (Tursiops truncatus) is the second most commonly encountered odontocete o... more The bottlenose dolphins (Tursiops truncatus) is the second most commonly encountered odontocete off the southern Pacific coast of Costa Rica, after the coastal pantropical spotted dolphin (Stenella attenuata graffmani). The species occurs beyond the 200 m isobath off Osa Peninsula, with frequent incursions to coastal waters. Bottlenose dolphins are also frequently sighted within inshore habitats of Golfo Dulce. This study examines the spatial distribution pattern of both ecotypes by analyzing the sighting records and relative density of bottlenose dolphins in two sub-areas: off Osa Peninsula (2001 -2006, n= 238) and Golfo Dulce (2005 -2011, n= 172). Kernel distribution maps were produced and the spatial distribution pattern quantified by means of the near neighbor index. Based on the external morphology of the animals seen and their off-shore / in-shore occurrence, we conclude that all records off Osa peninsula represent the oceanic ecotype (primarily off-shore sightings), whereas t...
Revista de biologia tropical
Diversity of cetaceans in coastal seascape Golfo Dulce, Osa Peninsula, Costa Rica. Golfo Dulce is... more Diversity of cetaceans in coastal seascape Golfo Dulce, Osa Peninsula, Costa Rica. Golfo Dulce is a fiord-lilke embayment located in the southern Pacific of Costa Rica, this coastal-marine ecosystem harbors an important wealth in marine biodiversity, including cetaceans. In this study we describe the cetacean community of Golfo Dulce, in relation to the diversity of habitats constituting the seascape. Sighting data collected in periodic systematic surveys has yielded 943 records (2005-2014≈3 490h≈64 533km), of 12 species of cetaceans. A gradient of cetacean diversity is observed from the inner basin to the transitional-oceanic area at the entrance of the Gulf, with coastal bottlenose dolphin and spotted dolphin dominating the inner basin, and bottlenose dolphins and migratory humpback whales the sill area. Transitional oceanic habitat holds the greatest species diversity dominated by oceanic species, particularly piscivorous delphinids, including the offshore form of bottlenose dolp...
Diseases of aquatic organisms, Jan 16, 2014
Lacaziosis (also known as lobomycosis) is a chronic dermal disease caused by the fungal agent Lac... more Lacaziosis (also known as lobomycosis) is a chronic dermal disease caused by the fungal agent Lacazia loboi, which affects both humans and dolphins. Photographic data have been used to identify lacaziosis-like disease (LLD) among dolphins in the waters of North and South America, and here we report LLD in bottlenose dolphins Tursiops truncatus off the coast of Costa Rica, the first reporting in Central American waters. During the periods of 1991 to 1992 and 2010 to 2011, 3 research teams conducted separate dolphin surveys in the Pacific tropical fiord Golfo Dulce, and each documented skin lesions in the resident population of bottlenose dolphins. Photo-ID records were used to identify LLD-affected bottlenose dolphins and to assess their lesions. Findings showed between 13.2 and 16.1% of the identified dolphins exhibited lesions grossly resembling lacaziosis. By combining efforts and cross-referencing photographic data, the teams explored the presence of LLD in Golfo Dulce over a time gap of approximately 20 yr. Our findings expand the geographical range of the disease and offer insight into its longevity within a given population of dolphins.
The identification of critical habitats for cetaceans is the foundation in the design and impleme... more The identification of critical habitats for cetaceans is the foundation in the design and implementation of Marine Spatial Planning, including the creation of Marine Protected Areas, associated with local cetacean fauna. Golfo Dulce is a tropical fjord-like embayment located in the southern Pacific coast of Costa Rica; it is among the best preserved marine habitats in the Osa Peninsula ecosystem. Baseline data on cetacean occurrence have been gathered in this region since 2005, focusing primarily on two sympatric populations of coastal delphinids, the pantropical spotted dolphin (Stenella attenuata graffmani) and bottlenose dolphin (Tursiops truncatus). The current study investigates the underlying behavioral mechanisms that govern patterns of niche differentiation and the resulting conservation implications. We focus on the foraging areas/habitats of high conservation importance due to the role they play in the day-to-day needs of the two dolphin species in their year-round presence in the inner basin of Golfo Dulce.
Humpback whales (Megaptera novaeangliae) aggregate in winter breeding and calving grounds along c... more Humpback whales (Megaptera novaeangliae) aggregate in winter breeding and calving grounds along continental margins, coastal islands, or archipelagos located in tropical waters. Migration to these breeding sites requires a long journey from northern feeding areas in temperate and circumpolar latitudes. The humpback whales habitat preference is generally restricted to coastal areas, and their tendency to concentrate in specific locations to reproduce exposes them to anthropogenic threats such as fishing, coastal development, water pollution, and marine traffic. There has been an increasing interest for coastal development projects that intent to capitalize the natural attributes of Golfo Dulce, in the southern Pacific coast of Costa Rica, potentially threatening the stability of the ecosystem and creating habitat disruption for the wintering population of humpback whales in the area. This contributions focalize in important ecological aspect related with areas use, particularly behavioral elements associated with the spatial aggregation of competitive groups, mother – calf pairs and vocalizing humpback whales. We identify areas with significant aggregation of mother- calf pairs that can be categorized as critical nursing areas, producing key baseline information to promote effective conservation and management strategies such as Marine Spatial Planning.