Publications
Bottlenose dolphin (Tursiops truncatus) aggregations at Cocos Island National Park, Puntarenas, Costa Rica, between 2017-2022
Research on bottlenose dolphin (Tursiops truncatus) aggregations at Cocos Island National Park, Costa Rica, from 2017 to 2022 reveals that the northeastern and southwestern quadrants serve as critical feeding grounds, likely due to high productivity near seamounts. The study found no significant seasonal or annual differences in sightings but noted an increase in individuals per group during 2020-2021, possibly linked to reduced human activity during the COVID-19 pandemic. While juveniles and pups were consistently present until 2022, their absence that year suggests potential shifts in habitat use or population dynamics. The research used systematic monitoring via the PRONAMEC protocol, dividing the park into quadrants and analyzing group composition, location, and seasonality to inform conservation strategies for this remote yet ecologically vital marine area.
Microplastic distribution in the marine and freshwater ecosystems of Cocos Island National Park, Costa Rica
A uniform distribution of microplastics (MPs) around Cocos Island National Park, Costa Rica, suggests that local human activities are not significant sources of MP pollution. The study, which analyzed 288 samples from marine and freshwater ecosystems, identified 178 MPs, with higher abundance and larger sizes found in the marine environment. While ocean currents likely contribute to marine MP distribution, sources in the freshwater ecosystem remain uncertain but may stem from atmospheric deposition, air-sea exchange, or long-range transport. These findings highlight Cocos Island's vulnerability to plastic pollution due to its insular nature and underscore the need for global conservation efforts to address MPs as a planetary boundary threat.
Seamount aggregation effects for threatened species at Cocos Island National Park: Insights from a Long-Term Monitoring Framework in the Eastern Tropical Pacific
A long-term monitoring study from 2021 to 2024 at Cocos Island National Park revealed that seamounts, particularly the West Cocos and Gemelas seamounts, serve as critical aggregation sites for threatened pelagic species such as hammerhead sharks, thresher sharks, and silky sharks. The research found significantly higher abundance and diversity of these species near the seamount peaks compared to areas 10 nautical miles away, highlighting the localized biological importance of these underwater features. Hammerhead shark populations were particularly sensitive to environmental factors like water temperature, thermocline depth, and oxygen levels. This study provides a baseline for assessing the effectiveness of the expanded Cocos Island National Park and supports the establishment of a regional seamount monitoring initiative through the MigraMar network, aiming to protect these vulnerable species in the Eastern Tropical Pacific.
Microplastics found in the World Heritage Site Cocos Island National Park, Costa Rica
A comprehensive study reveals the widespread presence of microplastics (MPs) in both marine and freshwater environments of Cocos Island National Park, Costa Rica. MPs were detected in 93% of marine sediments, 20% of marine fish, and 51% of marine lobsters, with ocean currents, tourism, and illegal fishing gear identified as primary sources. Unexpectedly, MPs were also found in freshwater environments, including 32% of freshwater sediments, 20% of freshwater fish, and 15% of freshwater shrimps, though their origins remain unclear. The study employed a multi-faceted sampling approach, collecting sediment samples and biota from both marine and freshwater habitats using nonselective nets, fishing rods, cages, and scuba diving techniques.
The Terrestrial Reptiles of Australia's Island Territories [1983]
Australia's oceanic territories, including Cocos Island National Park, harbor diverse but understudied reptile faunas. A 1983 survey of Norfolk, Christmas, and Cocos (Keeling) Islands revealed distinct reptile compositions, distributions, and conservation needs across these remote Pacific and Indian Ocean islands. Conducted over two-week periods by the Australian National Parks and Wildlife Service, the study aimed to document the current status of terrestrial reptiles, identifying species richness, local abundance, and potential threats. Findings highlighted the unique herpetofaunal characteristics of these islands, emphasizing the need for targeted conservation efforts to protect their biodiversity.
Approximation of the benefits of socioeconomic activities in Cocos Island National Park and the effects of climate change
In 2019, Cocos Island National Park (CINP) generated approximately US$19.7 million in socioeconomic benefits, with 88% of this value derived at the national level. The study highlights the park's significance as a driver for economic activities, particularly through its rich biodiversity, including critical marine species like the hammerhead shark (Sphyrna lewini). Researchers used cluster analysis and a value chain approach to map productive and non-productive activities linked to the CINP across local, regional, national, and international scales. The findings underscore the vulnerability of these economic benefits to threats such as overfishing and climate change, emphasizing the need for robust conservation measures to safeguard both ecological integrity and socioeconomic returns.
Rhodolitica on rhodoliths: a new stoloniferan genus (Anthozoa, Octocorallia, Alcyonacea)
Scientists have discovered and described a new genus of octocoral, Rhodolitica occulta, found exclusively on rhodoliths within Cocos Island National Park. This species, characterized by its unique tubular anthosteles interconnected by thin stolons and distinctive sclerite morphology, stands out due to the absence of fused sclerites in its anthosteles while retaining them in stolons. The research employed an integrative taxonomic approach, combining morphological comparisons with molecular phylogenetic analysis, to distinguish this genus from similar ones. The discovery highlights the biodiversity richness of Cocos Island and contributes to our understanding of marine life in the eastern tropical Pacific.
Marine biodiversity of an Eastern Tropical Pacific oceanic island, Isla del Coco, Costa Rica
Isla del Coco, a remote oceanic island in the Eastern Tropical Pacific and part of Costa Rica's largest national park, hosts one of the highest marine biodiversity concentrations in its region. A comprehensive compilation of published records identifies at least 1688 species, with gastropods, bony fishes, and crustaceans being the most diverse groups. Notably, 45 species (2.7% of the total) are endemic to the island's national park, underscoring its unique ecological significance. Despite this wealth of biodiversity, significant knowledge gaps remain, particularly in poorly studied regions such as the south side, pelagic environments, and deeper waters, as well as groups like flatworms, nematodes, nemerteans, and gelatinous zooplankton. This study synthesizes scattered historical and contemporary data to highlight both the richness and the unexplored potential of Isla del Coco's marine ecosystems.
Ultraviolet radiation at Isla del Coco (Cocos Island) National Park, Costa Rica.
Research at Cocos Island National Park, Costa Rica, reveals significant variations in ultraviolet (UV) radiation exposure, critical for understanding ecosystem dynamics and protecting coral reefs. The study found that UV index (UVI) averages ranged from 14 to 3 on sunny versus cloudy days in Chatham Bay, and 12 to 4 in Wafer Bay, with the sunniest conditions peaking at UVI 16. High UV exposure occurred between 9:00–15:00 in Chatham and 9:00–14:30 in Wafer during sunny periods. The study used automatic Davis weather stations to measure UV radiation over multiple expeditions (2008–2012), providing valuable data for modeling ecosystem impacts, ranger operations, and tourism planning.
Shifting elasmobranch community assemblage at Cocos Island—an isolated marine protected area
A significant decline in the relative abundance of eight elasmobranch species, including iconic sharks and rays such as scalloped hammerhead sharks (−45%), whitetip reef sharks (−77%), mobula rays (−78%), and manta rays (−89%), has been documented over 21 years at Cocos Island National Park. Conversely, the probability of occurrence for tiger, Galapagos, blacktip, and whale sharks increased significantly during this period. The study used mixed effects models to analyze data collected by divers, accounting for observer variation and abiotic factors. These findings highlight that marine protected areas (MPAs) may not effectively protect elasmobranch species unless enforcement efforts against fishing are strengthened. The research underscores the importance of tailored conservation strategies that consider life history traits and vulnerability to fishing pressure.
Optimizing enforcement and compliance in offshore marine protected areas: a case study from Cocos Island, Costa Rica
Illegal fishing at Cocos Island National Park, Costa Ricafollows predictable spatial and temporal patterns, offering potential for optimized enforcement. Analysis of patrol records revealed that illegal activity is concentrated on a seamount within the park and peaks during the third quarter of each year, likely due to oceanographic conditions. The lunar cycle also significantly influences the timing of incursions, suggesting that patrol efforts could be strategically allocated to reduce costs while maintaining compliance. Repeat offenders are common, with unenforced regulations and weak governance potentially contributing to non-compliance. The study provides actionable recommendations for improving enforcement efficiency, governance, and policy design in marine protected areas, with broader applicability to other conservation challenges.
Polychaetes (Annelida: Polychaeta) of Cocos Island National Park, Pacific Costa Rica
A comprehensive survey of Cocos Island National Park, Pacific Costa Rica, identified 106 polychaete species, with 103 being new records for the site. This highlights the island's rich but understudied biodiversity, particularly in comparison to the Galápagos Islands. The study suggests limited isolation between Cocos Island and mainland populations, likely due to larval or adult transport mechanisms such as rafting. Only two species had not been previously recorded along the Pacific coastline from Mexico to Chile, underscoring the island's unique but connected fauna.
The LanceletAsymmetron lucayanumComplex in Cocos Island National Park, Pacific Costa Rica
Researchers document the first occurrence of the lancelet Asymmetron lucayanum complex in the eastern Pacific, specifically within Cocos Island National Park. This discovery is significant as it expands the known distribution of this circumtropical species, which was previously unrecorded in the region. The study, conducted during a benthic survey, analyzed taxonomically significant characters such as myotome count and gonad placement to confirm the identification. Lancelets were found in subtidal sandy bottoms (5–42 m) with slightly gravelly, poorly sorted sediment. This finding contributes valuable baseline data for understanding marine biodiversity in this remote and ecologically important site.
Morphology and taxonomy of a new species of Leptogorgia (Cnidaria: Octocorallia: Gorgoniidae) in Cocos Island National Park, Pacific Costa Rica
A new species of shallow-water gorgonian coral, Leptogorgia tricorata, has been discovered at Cocos Island National Park, Costa Rica. This species is distinguished by its unique branching pattern, small size, bright yellow coloration, elongated spindles (up to 0.2 mm), and the presence of tentacular rods. Found at depths of 14–22 meters on rocky islets, L. tricorata represents a rare addition to the shallow-water gorgoniid diversity in the region, with only three species currently documented in the area. The discovery was made through morphological and taxonomic analysis, comparing the new species with other Leptogorgia species reported from the eastern Pacific. This finding contributes to our understanding of marine biodiversity in Cocos Island National Park.
The orchid flora of Cocos Island National Park, Puntarenas, Costa Rica
Cocos Island National Park, a remote oceanic island off Costa Rica's Pacific coast, hosts a diverse orchid flora comprising five species within its 24 km² area. Among these, three are endemic to the island: Epidendrum cocoense, E. insulanum, and E. jimenezii, alongside Camaridium micranthum and Ornithidium adendrobium (formerly classified under Maxillaria). The study describes these species morphologically, provides analytical illustrations, and offers a field identification key based on their characteristics. It also delves into their biogeography, ecology, taxonomy, evolution, and conservation status, contributing valuable insights to the understanding of this unique island ecosystem.
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