Tayrona National Natural Park Research Articles

Reproductive phenology of coralline algae Porolithon antillarum and Lithophyllum sp. under seasonal upwelling conditions, Colombian Caribbean

Crustose coralline algae are a group of calcified algae that has an important ecological role in coral reefs, such as cementation and stabilization of the reef framework, as well as providing habitat and food for different marine associates. Among the common genera, Lithophyllum and Porolithon (Corallinales) are conspicuous components of the Santa Marta reef communities in the Colombian Caribbean. From December to April, this area is influenced by seasonal trade winds, a phenomenon that is related to the upwelling of subsurface waters that causes a decrease in temperature from ∼29 °C to ∼22 °C and pH from ∼ 8.5 to ∼8.0. The aim of this study was to evaluate the effect of upwelling and non-upwelling (2017, 2018, and 2021) on the reproductive phenology of Lithophyllum sp. and Porolithon antillarum based on counts of superficial conceptacles per cm2 and a determination of the reproductive stages of the algae collected in Tayrona National Natural Park and Punta Venado, Santa Marta. The algae presented the highest number of mature conceptacles during the upwelling period for P. antillarum and Lithophyllum sp. (46 and 27 conceptacles cm2, respectively). Moreover, the tetrasporangial stage was the most frequent in all the thalli, thus indicating the predominance of this phase in the reproductive cycle of the algae studied. These results are important as they indicate the influence of seasonality on the reproductive stages of CCA and bring the need to do more research into the influence of the environment on the physiological mechanisms that determine the changes in the life cycle of these algae.

Seasonal Upwelling Conditions Modulate the Calcification Response of a Tropical Scleractinian Coral

Natural processes such as upwelling of deeper-water masses change the physical-chemical conditions of the water column creating localized ocean acidification events that can have an impact on the natural communities. This study was performed in a coral reef system of an archetypical bay within the Tayrona National Natural Park (PNNT) (Colombia), and aimed to quantify net calcification rates of a foundational coral species within a temporal context (6 months) taking into account the dynamics of seasonal upwelling that influence the study area. Net calcification rates of coral fragments were obtained in situ by the alkalinity anomaly technique in short-term incubations (~2.5 h). We found a significant effect of the upwelling on net calcification rates (Gnet) (p < 0.05) with an 42% increase in CaCO3 accretion compared to non-upwelling season. We found an increase in total alkalinity (AT) and dissolved inorganic carbon (DIC) with decreased aragonite saturation (Ωara) for the upwelling months, indicating an influence of the Subtropical Under Water mass (SAW) in the PNNT coral community. Significant negative correlations between net calcification with temperature and Ωara, which indicates a positive response of M. auretenra with the upwelling conditions, thus, acting as “enhancer” of resilience for coral calcification.

First record of the dinoflagellate Prorocentrum borbonicum in the continental coast of Colombian Caribbean: A new 42 hydroxi-palytoxin producer

The dinoflagellate genusProrocentrumincludes several harmful toxigenic species, predominantly benthic ones. In the past, fast-acting toxicity in mice has been observed in extracts of the epibenthic speciesP. borbonicum, with the finding of two compounds termed as borbotoxins-A and -B. The presence of palytoxin-like compounds was also suggested from electrophysiological experiments. In the present study, a strain ofP. borbonicumwas isolated in the continental coast of Colombian Caribbean, in seagrass beds ofThalassia testudinumin Bonito Gordo, Tayrona National Natural Park (PNNT). The morphological and molecular characteristics were consistent with the original and former descriptions for this species. Typical haemolytic activity due to palytoxin was confirmed inP. borbonicumextracts in presence of ouabain, the toxin contents being estimated as 1.9 pg palytoxin equivalents cell-1. HPLC-HRMS analyses of these extracts unambiguously identified the presence of borbotoxins and 42-hidroxy-palytoxin (42-OH-PLTX). This is the first report of palytoxin-like compounds in another dinoflagellate genus thanOstreopsisand the first record ofP. borbonicumin Colombia and the Caribbean region.

Cambios ambientales en los últimos 1800 años en el manglar de Neguanje, Parque Nacional Natural Tayrona, Caribe colombiano

We reconstructed changes in vegetation and climate conditions during the last 1800 years in a column of sediment 4 m deep (Playa Pozo sector, Neguanje Bay, Tayrona National Natural Park, department of Magdalena, Colombia). We characterized the main components (mineral elements, organic matter), micro-stratigraphy (types of organic matter), humidity variations (%), organic and inorganic carbon, and palynological associations (specifically pollen grains), and counted spores of fungi, algae, ferns, plant debris, and insects. The palynological associations (dominant elements) were defined and related to the current types of vegetation. The definition of the dominant groups in the palynological spectrum and their relationship with the current vegetation types was associated with the stratigraphic conditions of the sediments to detect the changes that occurred during this period. In the reconstruction of the paleoenvironments, we determined the relationship between the defined palynological associations and the stratigraphy of the sediments, the humidity (precipitation), and the covered area. For this purpose, we used the temperature calibration curves of the last 2000 years proposed by various authors. We did not recover enough palynomorphs at the base of the column between 400 and 380 cm deep (2000-1693 years BP), but organic components of marine origin predominated in the sediment, a condition associated with a warm period in the central and eastern Colombian Caribbean coastal environments. In zone I (1693-1294 years B.P.), the mangrove was consolidated and in zone II (1294-1078 years A.P.), it expanded with the vegetation of flooded areas. In zone III (1078-654 years B.P.), we detected the occurrence of the greatest mangrove development, especially by the dominant species Rhizophora mangle. In zones IV and V (654 years A.P.-present), the mangrove cover decreased. This period was less warm than the previous ones, similar to the prevailing conditions in the Ciénaga Grande de Santa Marta and its surroundings.

Effect of Maritime Traffic on Water Quality Parameters in Santa Marta, Colombia

Since 2013, there has been an increase (>23%) in naval traffic using maritime routes and ports on the coastal fringe of Santa Marta, Colombia. Of major concern, and described by several studies, is the relationship between maritime traffic and coastal contamination. This study proposed a maritime traffic indicator considering the simultaneous effects of several relevant measurements of water quality parameters to estimate the impact of naval activity. The approach involved developing a model including the number of vessels, hull length, and permanence time in berths. In addition, water quality variables, considering climatic seasons, were used to verify association with maritime traffic and touristic activities. The high concentrations of total coliforms (TC) and dissolved/dispersed petroleum hydrocarbons in chrysene equivalents (DDPH) reported by the International Marina of Santa Marta (SM) were affected by the local anthropic activities, including tourism, naval traffic, and urban wastewater discharges. Moreover, our results suggest the occurrence of multiple chemical impacts within Tayrona National Natural Park (PNNT) affecting conservation goals. The estimation of the maritime traffic indicator proposed in this study may be an easy and more complete tool for future studies evaluating the impact of naval activities on environmental quality.

Morphological and molecular characterization of Gambierdiscus caribaeus (Dinophyceae), with a confirmation of its occurrence in the Colombian Caribbean Tayrona National Natural Park

Abstract Dinoflagellates in the genus Gambierdiscus are known to produce potent neurotoxins known as ciguatoxins. These toxins vector through the food web and can reach sufficiently high levels to cause ciguatera fish poisoning (CFP). In many regions of the Caribbean, little is known about the occurrence of CFP-causing species or the incidence of CFP, despite its apparent regional increase over the last few decades. Given the intraspecific variability in content and potencies of these toxins among Gambierdiscus species, the precise identification of local species of this genus is crucial. In this study we confirm the presence of the epibenthic dinoflagellate Gambierdiscus caribaeus in the Colombian continental Caribbean. Cells were collected in seagrass beds of Thalassia testudinum in Bonito Gordo, a site located on the western side of Bahía Concha, Tayrona National Natural Park, near the city of Santa Marta, Colombia. Subsequently, a single strain of Gambierdiscus could be established for further identification. Morphological (light and scanning electron microscopy), and molecular results (partial LSU and ITS rDNA sequencing) were consistent with the original description of G. caribaeus, as well as with the morphological characteristics shown by other authors in organisms obtained near the sampling area.

Medium and large-sized mammals in dry forests of the Colombian Caribbean

Mammalian populations are fundamental at functional and ecological levels within ecosystems and are inconstant threat of reduction world wide and in the Neotropic. We evaluated population variables, habitat use, and threats to medium and large mammals (weight > 1 kg) in the terrestrial part of the Tayrona National Natural Park (Santa Marta-Colombia). We carried out in direct annual observations with camera traps between 2012 and 2017, both in rainy and dry seasons. We estimated the richness, relative abundance (RAI), and functional diversity of the mammals present in the area. We recorded 15 species, distributed in seven orders (Carnivora, Rodentia, Pilosa, Cingulata, Lagomorpha, Didelphimorphia, and Cetartiodactyla), 11 families and 13 genera. The species with the highest capture frequency was Dasyprocta punctata (142, RAI = 0.85), followed by Cuniculus paca (56, RAI = 0.33), Odocoileus virginianus (51, RAI = 0.30), and Cerdocyon thous (41, RAI = 0.24). We observed a marked use and preference of habitat in the seasonal dry ever green forest. This finding coincides with the highest value of functional richness (S1= 293.88) for this ecosystem, probably due to its features, such as green vegetation and abundant water streams. Our results reveal stability of the species richness across the years studied, suggesting good health of the mammal populations in the studied area.

Valoración actual de las poblaciones de Acropora palmata y Acropora cervicornis en el Parque Nacional Natural Tayrona, Caribe colombiano

La última valoración sobre la extensión, estado y cobertura viva (%) de las formaciones de Acropora palmata (29) y A. cervicornis (12) en el Parque Nacional Natural Tayrona fue realizada en 2001 y publicada en 2004. Estas mismas formaciones, incluyendo una adicional en isla Aguja, fueron evaluadas de nuevo entre 2016 y 2018 teniendo en cuenta las mismas variables, y adicionalmente el registro de condición de las colonias. Para A. palmata se encontraron 24 formaciones con una reducción en área de 28,9 %. La cobertura promedio aumentó cerca de 2,0 %, y se observó una amplia distribución de frecuencia de tallas y una proporción importante de colonias con territorios de peces damisela (Stegastes). El área de las formaciones de A. cervicornis se redujo 99,3 % y solo se encontró una formación en Nenguange, aunque se registran dos nuevas y pequeñas en Cinto y otra en Chengue. La cobertura promedio fue de 8,0 %, en su mayoría constituida por colonias de talla pequeña y principalmente afectadas por blanqueamiento, macroalgas, enfermedades y depredadores. Claramente el estatus de las dos especies es diferente por lo que requieren esfuerzos diferentes para su manejo y conservación. Las formaciones de A. palmata han persistido, pero es necesario realizar estudios continuos que permitan detectar cambios temporales, con evaluaciones de aspectos ecológicos como las afectaciones por los peces damisela. El estado de A. cerviconis es crítico, por lo que demanda acciones urgentes de restauración y otras medidas de manejo para mitigar la tendencia a su desaparición en el área.

Estructura de la comunidad de céspedes algales en interacciones con corales masivos en arrecifes del Parque Nacional Natural Tayrona, Caribe colombiano

ecidos y en interacción directa con corales masivos, y se relacionó su complejidad estructural con la capacidad de retención de sedimentos. Para ello, se determinó la composición taxonómica y se cuantificaron la altura del dosel, la cobertura y densidad de filamentos y la biomasa algal de los céspedes que crecían sobre colonias vivas de cuatro especies de corales. Los resultados mostraron que existen diferencias estructurales importantes entre arrecifes y tipo de sustrato. En el arrecife de Granate (10-16 m), los céspedes forman tapetes discontinuos entre algas costrosas, y están constituidos por algas calcáreas articuladas, pequeñas corticadas y juveniles de algas frondosas, principalmente del género Dictyota. Durante el afloramiento costero este género crece profusamente formando transitoriamente tapetes densos que luego se desprenden. Por el contrario, en el arrecife de Nenguange (4-6 m), los céspedes son perennes, forman tapetes muy bajos, tupidos y densos con escasas algas costrosas, y están dominados por algas filamentosas y pequeñas corticadas. Se sugiere que la presencia de territorios de damiselas del género Stegastes ayuda a controlar la complejidad estructural de los céspedes, y que la propagación vegetativa es el mecanismo de crecimiento más frecuente. Además, se encontró que los céspedes morfológicamente más complejos retienen mayor cantidad de sedimentos (limos-arcillas). Este material particulado les sirve de soporte; pueden avanzar lateralmente y ahogar el tejido coralino adyacente. Esta investigación provee los primeros datos cuantitativos de la estructura y cantidad de sedimentos retenidos por céspedes algales que crecen sobre corales arrecifales de Colombia.

Individual identification patterns as a monitoring strategy for American crocodiles: Tayrona National Natural Park as a study case

Abstract Population numbers of the American crocodile in Colombia have shown an increasing trend during the last decades. However, the lack of monitoring programs has restricted our understanding about this species’ ecology, limiting the ability to develop sound conservation plans. We assessed the effectiveness and robustness of the Individual Identification Pattern Recognition (IIPR) method for remotely monitoring American crocodile populations based on photographs taken by researchers, tourists, locals, and employees at the Tayrona National Natural Park (TNNP). We catalogued a total of 97 events from 2008 to 2020; 34.02% of which were suitable to analyze using IIPR. We identified eight individuals across 33 events that required only 4.71 ± 1.70 transverse scute lines to obtain complete identification, with the lowest levels of variation in the post occipital and nuchal regions compared with the dorsal area. The probabilities of repeating both the most and least common patterns found in the TNNP were 1.88 × 10−6 and 1.81 × 10−12, respectively, and the probabilities of repeating the same pattern of each individual identified ranged between 48.73 × 10−11 and 15.24 × 10−8. Animals B and C were continuously identified between 2012 and 2020 along the Arrecife beach coastline, whereas animals A, H, E, and F were occasionally registered between 2008 and 2019 at the Cañaveral beach. Overall, the IIPR method looks as a promising tool for monitoring American crocodile populations in the TNNP albeit some improvements in data collection that must be done to increase the number of useful events and analysis quality.

Tracking a voyager: mitochondrial DNA analyses reveal mainland-to-island dispersal of an American crocodile (Crocodylus acutus) across the Caribbean

Abstract Conservation efforts have allowed American crocodile (Crocodylus acutus) populations to recover to the point that dispersal movements are beginning to be documented. The environmental authority of San Andres Island in Colombia reported, for the first time, the arrival of two C. acutus from unknown localities in 2012 and 2018. The former was sacrificed, and the latter was captured and kept in captivity to determining its potential origin. We used wildlife forensics to establish the origin of the animal that arrived in 2018 based on two mitochondrial genes (COI and Cytb). Additionally, five other samples from Tayrona National Natural Park (TNNP), and Salamanca Island Road Park (SIRP) were sequenced for molecular attribution of these populations to the currently described lineages. Phylogenetic and phylogeographic analyses showed that the American crocodile found in San Andrés belongs to a continental evolutionary lineage endemic to Colombia, showing also a strong genetic similarity with animals from SIRP. Thus, the most likely origin for this individual was not the nearest continental area but somewhere around the central Colombian Caribbean, located ~700 km from the island. We discuss the implication of our findings in the systematics and conservation of the species and the potential of mitochondrial DNA analysis to identify such migrants.

Does ecotourism impact biodiversity? An assessment using dung beetles (Coleoptera: Scarabaeinae) as bioindicators in a tropical dry forest natural park

Abstract Ecotourism can be defined as an environmental activity that takes place in well-preserved areas for recreation and with the responsibility of promoting their conservation. Nowadays, ecotourism is seen as a friendly pastime, but it can potentially affect negatively community diversity and structure by a number of processes such as soil compaction, erosion, and habitat alteration, among many others. Nonetheless, there is hardly any information on the impact of ecotourism in the Tropical Dry Forests and protected areas of the Neotropical region. In an attempt to fill this knowledge gap, the effect of ecotourism was evaluated in a study of a Tropical Dry Forest in the Tayrona National Natural Park of Colombia using dung beetles as bioindicators. A large-scale sampling of three sites with different levels of tourism intensity (no tourism – NT, low tourism – LT, and high tourism – HT) was performed using pitfall tramps baited with human/pig dung during two climatic seasons (rainy and dry). A total of 3238 individuals belonging to nine genera and 15 species were collected. Significant differences in abundances, richness, and the Shannon Wiener diversity index were observed between areas with tourism and those without. These differences disappeared during the dry season in response to the strong reduction in species abundance and richness associated to that time of year. All areas maintained a homogeneous beetle structure in terms of functional groups present irrelevant of the intensity level of tourism. Beta diversity analysis shows that the dung beetle assemblage has a nested structure, indicating that the pressure exerted by tourism entails the loss of particular species. Our results advocate that it is necessary to implement conservation strategies in order to reduce the negative impact of tourism on the National Park’s biodiversity.

Magnitude and Causes of Beach Accretion on the Eastern Margin of the Tayrona National Natural Park (Colombian Caribbean)

Manzolli, R.P.; Portz, L.; Villate, D.A.; Contreras, M.D.; Padilla, L.C.J., and Alcantará-Carrió, J., 2020. Magnitude and causes of beach accretion on the eastern margin of the Tayrona National Natural Park (Colombian Caribbean), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 299–303. Coconut Creek (Florida), ISSN 0749-0208.Beaches on the eastern margin of Tayrona National Natural Park experienced stability and even accretion over the last decade, in contrast to general erosion along the Colombian Caribbean coast. The objective of this study is to characterize shoreline change and analyze the factors contributing to the accretionary trend. Orthorectified satellite images, combined with topography from both drone images and RTK-DGPS measurements, were used to map successive shorelines from 2002-2008. Net shoreline movement and shoreline migration rates revealed these beaches had an accretionary trend, with the exception of Piscina Beach that eroded during the time period. The maintenance of natural inputs of sediment from local rivers, redistributed by littoral drift with sediment bypassing across the small headlands limiting the beaches, the resilience of the beaches to the impact of hurricanes and low human pressure allows for a positive sedimentary budget for the beaches. Piscinas Beach is the most cut off from fluvial sediment input, and despite it has a coral reef barrier, its dissipative profile indicate that it is the most exposed to wave impact.

Parámetros de crecimiento de Cardisoma guanhumi en el departamento del Magdalena, Colombia

In Colombia, the blue land crab Cardisoma guanhumi faces two main threats: extraction and habitat loss. This project aims to show an approximation of the growth parameters of C. guanhumi in protected areas within the Magdalena department. Individuals were captured monthly from May to October 2016 in five localities in the Tayrona National Natural Park (PNNT) and the Salamanca Island Road Park (VIPIS). A total of 816 crabs were collected, each of which was measured, weighed, sexed and released. Both sexes showed a negative allometric length-to-weight ratio. Using the FiSAT II program's ELEFAN I routine, the size frequencies obtained were analyzed in order to determine the growth parameters for 1) the department, considering gender, and 2) the PNNT, where the data from VIPIS wasexcluded. The asymptotic carapace width was higher for males (109.16 mm) than for females (96.74 mm), but the growth coefficient (K) was higher for females (0.19 year-1) than for males (0.15 year-1). Growth performance indexes were similar: 3.252 for males and 3.250 for females. The FISAT II length converted catch curve routine was used to calculate the total (Z), natural (M), and fishing (F) mortalityrates, as 0.41, 0.36, and 0.05 year-1 respectively. The grow coefficient K was higher for the PNNT (0.29 year-1) than for the Magdalena department (0.15 year-1), thus, longevity was lower for the PNNT (tmax= 10.42 years) compared to the department (tmax= 20.06 years). Ingeneral terms, the C. guanhumi population in the study area is longevous, slow growing, with low extraction morality. The data obtained in this work are important in the management of this species, as its slow growth makes it vulnerable to overfishing.

Mortalidad de vertebrados silvestres en la carretera Troncal del Caribe, Magdalena, Colombia

Road networks cause great impacts on the environment, from the direct mortality of wild animals that are hit by moving vehicles to the reduction of connectivity in the landscape and the isolation of natural populations. In Colombia, studies on wildlife roadkill are incipient, and there are still many gaps in the generation of primary information, especially on the roads of the Caribbean coast. For this reason, we selected two road stretches in the Colombian Caribbean region: 1) Isla Salamanca National Natural Park highway (45 km) and 2) Tayrona National Natural Park highway (34 km). On both roads, monthly trips were made on board a vehicle at a maximum speed of 30 km/h during 5 months, between October 2016 and January 2017. We recorded a total of 208 roadkills (46 identified species), being reptiles and mammals the most affected groups in segments 1 and 2, respectively. Finally, we calculated the roadkill rate (TA) for each species. The species Boa constrictor and Procyon cancrivorus stand out because they obtained highest TA values reported in Latin America

Molecular detection of Rickettsia spp., Anaplasma platys and Theileria equi in ticks collected from horses in Tayrona National Park, Colombia.

Horses are among the domestic animals that closely interact with humans and are highly parasitized by ticks, which are the primary vectors of zoonoses. As horses in Tayrona National Natural Park (PNNT) are used as a means of transporting goods, luggage and people, they are in constant contact with wild animals, workers and tourists from different countries. These factors increase the transmission risk of hemoparasites. The purpose of this study was to determine the presence of Rickettsia sp., Anaplasma sp., and Theileria sp., in horse ticks in this protected area using conventional PCR. We collected 343 ticks of genera Amblyomma, Rhipicephalus and Dermacentor. Of the 61 samples analyzed by PCR, 18 (29.5%) individuals were positive for Rickettsia sp., 15 (24.5%) for Anaplasma sp. and 4 (6.6%) for Theileria sp. This is the first report of these hemoparasite genera in ticks associated with horses in this preserved natural area, demonstrating the importance of additional studies on the presence and epidemiology of hemoparasites and their vectors in domestic and wild animals in conserved areas with a high flow of tourists.

Captura incidental en nasas del pez león Pterois volitans (Scorpaeniformes: Scorpaenidae) en el Caribe colombiano

Incidental catch in traps of the lionfish Pterois volitans (Scorpaeniformes: Scorpaenidae) in the Colombian Caribbean. Since 2011, small-scale fishermen from Taganga Bay (Colombian Caribbean) have been catching lionfish in traps in the Tayrona National Natural Park, which had caused them to believe that the lionfish is the cause of the decrease in overall fishing. In order to determine the changes in the species captured and to know the abundance of the lionfish in this fishing method, we analyzed the historical landings in traps between 1993 and 2014, as well as the landing of three fishing units between March 2012 and July 2014. The historical analysis showed that the decline in species and kilograms landed has been occurring since 2000. A total of 4 913 specimens were landed between March 2012 and July 2014, of which 85 % were species of commercial interest, and the rest were used by fishermen for consumption. Landings between 2012 and 2014 were conditioned by climatic conditions, where the co-occurrence between Pterois volitans and the main commercial species and self-consumption did not provide evidence of the lionfish affecting its abundance. This confirms the presence of the lionfish as a new member in the landings in traps the Taganga Bay.

Evaluación de la sustentabilidad de los prestadores de servicios turísticos del Parque Nacional Natural Tayrona en el departamento de Magdalena, Colombia

Se presenta un modelo de evaluación de sustentabilidad de los prestadores de servicios turísticos (PST) que operan el Parque Nacional Natural Tayrona, Magdalena, Colombia. Para su desarrollo, se contó con experiencias sobre buenas prácticas realizadas por los PST en parques naturales. Esta revisión permitió avanzar en el desarrollo de una investigación cuantitativa, en la que se valoró la sustentabilidad de los PST, basado en un modelo estadístico de construcción de índice sumatorio ponderado. Se analizaron 157 buenas prácticas, donde los resultados muestran que el 9,1% de los PST se encuentra en nivel alto del índice de sustentabilidad, mientras que el 27,3% se encuentra en el nivel bajo. En conclusión, la figura jurídica de concesión no es la mejor estrategia de gestión ni tampoco los PST son mejores en el momento de implementación de buenas prácticas.

Primer registro del pez vaca cola amarilla Hypoplectrus chlorurus (Serranidae) en el Caribe continental colombiano

The yellowtail hamlet, Hypoplectrus chlorurus (Cuvier) (Serranidae), is reported for the first time in the Colombian continental Caribbean. One individual of this species was collected during January 2014 in Bahía Concha (Concha Bay), Parque Nacional Natural Tayrona (Tayrona National Natural Park), at a depth of eight meters.

Dinoflagelados epífitos de Thalassia testudinum en dos sistemas costeros del Caribe colombiano

Studies on potentially toxic epibenthic dinoflagellates have been increased in the last years due to growing number of harmful events attributed to some of these microalgae. These events represent a risk to human health, as well as to diverse economic activities. With the aim of confirming the presence of these dinoflagellates in Tayrona National Natural Park, Colombian Caribbean, monthly samples of the seagrass Thalassia testudinum were collected between January 2014 and December 2015 in two coastal systems (Bay and Lagoon) located in Chengue Bay (11°20´ N y 74°07´W). Grass leaves were manually collected, placed in plastic bags with seawater and transferred to laboratory for detachment of epibenthic microalgae by vigorous shaking. To identify the species, three types of microscopy were used (optical, inverted with epifluorescence and scanning electron microscopy). Fourteen species of potentially toxic epiphytic dinoflagellates, distributed in four genera (Gambierdiscus, Coolia, Ostreopsis and Prorocentrum) were identified. Prorocentrum was the most representative genus. Ostreopsis cf. ovata, P. hoffmannianum and P. lima were the most frequent species in the Bay, whereas Prorocentrum sp. 1 and P. rhathymum were the most frequent in the Lagoon. This study depicts the main features of the observed species, considering that precise identification at species level is required for any ecological study that seeks to provide elements for risk management against the toxic or harmful effects caused by epibenthic dinoflagellates.