Santa Elena Peninsula Research Articles

A new species of Heterogorgia Verrill, 1868 (Octocorallia, Malacalcyonacea) from a mesophotic fishing shoal in the eastern Pacific

Heterogorgia abdita sp. nov. is a newly identified mesophotic octocoral species collected at Tigre shoal off Santa Elena Peninsula (Pacific Costa Rica). The new species is described based on distinctive morphological characters that classify it within the genus Heterogorgia. It is characterised by its conspicuous small branching colony with prominent calyces and thin branches. While its scleroma aligns with the genus, the presence of club-like spindles is notable, as these have previously been observed only in the sole Atlantic Heterogorgia species. This study enhances our understanding of the intriguing genus Heterogorgia and contributes to the knowledge of octocoral biodiversity within the Área de Conservación Guanacaste north Pacific Costa Rica and the broader marine biodiversity of the eastern tropical Pacific.

Sustainable Design for Geotourism Interpretation Centres: Enhancing the Santa Elena Peninsula Geopark Project Experience

Geosites represent important elements of geoheritage for promoting geotourism sustainable practices aimed at education and conservation. The Santa Elena Peninsula Geopark Project has several locations with geological, cultural and historical richness and the potential for geosites and tourist development. However, these places lack infrastructures that improves tourist reception and local geoeducation. In this study, Geotourism Interpretation Centres (GICs) were designed using sustainable and architectural criteria to improve geoeducation and geotourism in geosites of the Santa Elena Peninsula Geopark Project. The work included two stages: (i) selection of the geosites and (ii) design of the GICs. Four geosites were selected for the design: Barrio Ingles Ancon Parish, Manglaralto’s Coastal Aquifer, San Vicente Hot Springs, and San Rafael Mines. A GIC design adaptable to the four sites is proposed based on three zones: recreational–passive, services and cultural. The design prioritises sustainability, considering four criteria: political–economic, social, cultural and environmental. The proposal takes advantage of the area’s natural materials and the natural climatic conditions to offer a space that improves the geotourism experience in mimicry with the environment, promoting cultural roots and community benefit.

Percepção dos atores educacionais: aulas presenciais para as virtuais em tempos de pandemia

Introduction: experimentation is an essential tool in learning, allowing an explanation of how knowledge integrates within a scientific academic community. Objective: to analyze the perception of students, teachers, and administrative staff regarding the delivery of practical classes in General Chemistry through virtual modality (use of laboratories) at the State University of the Santa Elena Peninsula (UPSE) in Santa Elena, Ecuador, amidst the health emergency caused by COVID-19 during 2020. Methodology: a mixed approach with an exploratory scope was employed, utilizing survey techniques with an instrument consisting of 15 parametric questions (10 closed-ended and 5 open-ended), exhibiting a reliability of 0.767 in Cronbach's Alpha; the research was non-experimental, adopting a cross-sectional cohort, encompassing the entire sample (133 individuals). Results: Over 50% of educational stakeholders encountered difficulties adapting to the new educational system, highlighting the limited use of ICT. Conclusion: the COVID-19 pandemic exposed certain institutions' lack of readiness for remote learning, unveiling numerous challenges when transitioning from in-person to virtual classes across the educational community. While the quarantine was initially a temporary measure, it has been regarded as a starting point to envision the future of higher education, where virtuality could establish itself as a new norm.

Evaluating the impacts of agricultural development and climate change on the water-energy nexus in Santa Elena (Ecuador)

A combination of a changing global climate coupled with rapid socio-economic development is putting unprecedented pressure on water, energy, and food resources. Addressing these issues within a nexus approach can help to identify appropriate management practices and strategic policies to ensure natural resources are used more sustainably thus avoiding exacerbating issues of water scarcity and food insecurity. In this study, we used an integrated water resource planning and irrigation model (WEAP) to assess emerging water-energy nexus issues on the Santa Elena peninsula in Ecuador. Simulated water demands showed that current water resources availability is insufficient to meet full irrigation requirements, especially during the dry season. Annual average energy demand for water conveyance in the SEP was significantly higher than for irrigation with 94.5 GWh and 13.5 GWh being used, respectively. Future challenges associated with changes in agricultural irrigation and urban demands within the SEP were evaluated using scenario analysis. This included considering various scenarios such as agricultural expansion, climate change, population growth, and a shift to export-oriented agriculture. The study underscores the significance of nexus thinking in guiding policy and decision-making in Santa Elena, although the limited data prevents its use in an operational framework. The benefits of adopting an integrated modelling approach to analyse water and energy nexus trade-offs are also discussed.

Structural evolution of the southern Ecuadorian forearc in the Santa Elena Peninsula region

The southern Ecuadorian forearc system is related to the subduction of the oceanic Farallon/Nazca Plate beneath the continental South American Plate since the Late Cretaceous, and currently evolves with the dynamic of a tectonic block called North Andean Sliver. To explore the structural architecture and processes controlling the Upper Cretaceous-Cenozoic growth of the forearc, we built a ∼143 km-long onshore-offshore crustal-scale cross-section in the Santa Elena Peninsula region using seismic reflection profiles and well and field data. The structure of the Santa Elena Peninsula forearc system is controlled by imbrication of Upper Cretaceous-Palaeocene oceanic basement and Cenozoic sedimentary units, and underplating of distal Cenozoic sequences stacked at the trench zone. This led to the progressive construction of an accretionary wedge through time. The forearc substratum is mainly formed by the Upper Cretaceous-Palaeocene basement developed during the docking of oceanic terranes. It is later deformed by NW-trending landward-dipping, normal to strike-slip faults during the Middle Eocene, and renewed compression by inversion of inherited faults from the Oligocene onwards. Recent deformation consists in N-trending oceanward-dipping normal faults in the frontal slope domain and fault-controlled uplift of marine terraces along the coastal area. Therefore, the Upper Cretaceous to present-day structural evolution of the Santa Elena Peninsula forearc is controlled by the long-lasting subduction dynamics and structural inheritance of the upper plate.

A scenario-specific nexus modelling toolkit to identify trade-offs in the promotion of sustainable irrigated agriculture in Ecuador, a Belt and Road country

Increased demand for food due to development and population growth has prompted irrigated agriculture expansion, posing enhanced global challenges to water, energy, and food security. To confront these challenges, an approach that considers the water-energy-food-environment nexus can address multidimensional trade-offs that complicate the efficient use of resources and the achievement of Sustainable Development Goals. In order to provide insights into solutions to these challenges for a specific case, this study develops a modelling toolkit that integrates biophysical and socioeconomic aspects of nexus components in the context of agro-export and irrigation expansion in Ecuador, a Belt and Road Country. The nexus toolkit is applied to agricultural-development scenarios defined in participatory workshops and incorporates a water resources model, a lifecycle environmental assessment, and a socioeconomic analysis. The modelling exercise is constructed around specific scenario-determined land use patterns in the Santa Elena peninsula of Ecuador. Agriculture in the peninsula is water-limited, relying on delivery infrastructure and transfers from a neighbouring catchment. Impacts on nexus components are analysed for ten crops under two potential land-use scenarios: a substantial increase in irrigated area due to investment in irrigation infrastructure; and a substantial shift in land use towards export crops. The two have distinct impact on water and energy use, global warming potential, freshwater eutrophication, terrestrial acidification, and fine particulate matter formation. The results provide insights into future water and energy resource challenges and environmental and socioeconomic trade-offs associated with likely changes in irrigation expansion. The results for scenarios show that, for example, banana production has the greatest environmental impacts (e.g. a 519% increase in global warming potential and 452% increase in fine particulate matter form for scenario 2), primarily due to water and energy requirements, despite the crop being mainly produced organically. In addition, total net income and labour demand increase (net income increases by 43% and 217% under scenarios 1 and 2, respectively) due to a larger crop area and crop intensification. Scale effects on labour demand are mainly due to labour intensity of maize in Ecuador, which is disadvantaged in the crop export scenario (an unexpected result). However, expanding irrigated areas would also increase total water and energy demand for irrigation, global warming potential, and freshwater eutrophication. This type of information enables stakeholders and decision-makers to design policies that achieve equitable and sustainable agricultural production, water use, and economic growth.

Geochemistry and microbiology of tropical serpentine soils in the Santa Elena Ophiolite, a landscape-biogeographical approach

The Santa Elena Ophiolite is a well-studied ultramafic system in Costa Rica mainly comprised of peridotites. Here, tropical climatic conditions promote active laterite formation processes, but the biogeochemistry of the resulting serpentine soils is still poorly understood. The aim of this study was to characterize the soil geochemical composition and microbial community of contrasting landscapes in the area, as the foundation to start exploring the biogeochemistry of metals occurring there. The soils were confirmed as Ni-rich serpentine soils but differed depending on their geographical location within the ophiolite area, showing three serpentine soil types. Weathering processes resulted in mountain soils rich in trace metals such as cobalt, manganese and nickel. The lowlands showed geochemical variations despite sharing similar landscapes: the inner ophiolite lowland soils were more like the surrounding mountain soils rather than the north lowland soils at the border of the ophiolite area, and within the same riparian basin, concentrations of trace metals were higher downstream towards the mangrove area. Microbial community composition reflected the differences in geochemical composition of soils and revealed potential geomicrobiological inputs to local metal biogeochemistry: iron redox cycling bacteria were more abundant in the mountain soils, while more manganese-oxidizing bacteria were found in the lowlands, with the highest relative abundance in the mangrove areas. The fundamental ecological associations recorded in the serpentine soils of the Santa Elena Peninsula, and its potential as a serpentinization endemism hotspot, demonstrate that is a model site to study the biogeochemistry, geomicrobiology and ecology of tropical serpentine areas.Graphical

Academic dishonesty and its impact on virtual education

Academic dishonesty has been widely addressed in studies worldwide, highlighting the increase that this practice has had in regard to the educational context. The interest of the authors was to present a broader view of a real problem in higher education. The main objective of this research was to examine the incidence of academic dishonesty in virtual education from a perspective framed in the context of university education based on theoretical analysis and empirical investigation. The study was based on a predominantly qualitative mixed approach, where theoretical and empirical methods were applied, such as the analytical-synthetic in which theoretical references on the subject were analyzed, determining the main indicators that laid the conceptual bases of the investigation, the deductive -inductive that circumscribed the framework of the research and as an empirical instrument the survey with closed questions applied to 260 students of different academic levels from three universities in the coastal region of the country, which are: Santa Elena Peninsula State University, Salesian Polytechnic University of the Ecuador and the Technical University of Manabí. The results were obtained by quantifying the percentage of frequency in each of the response options for each question.

Geochemical characterization of crude oils and potential source rocks from southern coastal Ecuador: Hypothetical petroleum systems

This research paper encompasses an organic geochemical investigation on oils and sedimentary rocks from the southern coastal region of Ecuador that examines the hydrocarbon generation and accumulation in the strata of Progreso Basin Province. This petroliferous province represents an interesting area for an oil geochemistry study due to its non-elucidated petroleum systems. The present work focuses on the analysis of eighty-five oils and forty rock samples to determine kerogen types, depositional paleoenvironments, levels of thermal maturity, and in-reservoir petroleum biodegradation stages as well as to assess correlations between source facies and oil samples. Potential source rocks were selected and analysed from different outcrops and wells throughout the basin and the southern Gulf of Guayaquil. Classic biomarker, extended diamondoid, and isotope studies indicated that almost all oils from the Progreso Basin Province underwent biodegradation and were generated from multiple Tertiary source rocks deposited in a marine setting with significant influx of terrestrial organic material. Three families of oils were identified. Oil-source rock correlations suggest that the Socorro, Dos Bocas and San Eduardo formations can be considered as contributors to the studied oils. Geochemical data and previous thermal models point towards two probable hydrocarbon kitchens defined in the deepest parts of the basin as well as a third possible kitchen extended offshore beyond the Santa Elena Peninsula.

The Chongón/Colonche orocline transrotational bending and the coeval opening of the Progreso basin in southwestern Ecuador

Integration of geological and geophysical studies of Progreso Basin in SW Ecuador provided a unique opportunity to propose an unorthodox model for the Progreso Basin opening within a strike slip regime. Shearing couple transrotation of the Chongón/Colonche (C/C) orocline bending accounted for the atypical, isosceles triangle shape, Progreso Basin opening during the Oligocene oblique convergence amid the Farallon and South America plates. Transrotation commenced with the sinistral strike slip reactivation of the Paleocene Chongón-Jipijapa-Jama (CJJ) Suture. This suture is inferred based on field kinematics of Cretaceous outcrops in the Santa Elena Peninsula and published high resolution potential field maps. The reactivated suture worked as the sinistral La Cruz (LCF) Fault and their “en echelon” synthetic Riedels C/CF, Consuelo (COF), and Carrizal (CAF) faults accommodated most of the basin heterogeneous transtension and transrotation. While the synthetic Riedels migrated northward along the La Cruz Fault, a narrow segment of the Paleogene foredeep and the intra-oceanic arc sequence of the C/C High attached to the Estancia Hills was scrapped off and rotated. The shearing couple between the “en echelon” Riedels enhanced the transrotation and transtension and triggered the counterclockwise crustal rotation of the C/C High. The subvertical block rotation involved significant lithospheric decoupling of this high that set off the C/C Orocline development and coeval opening of the Progreso Basin.Early Zapotal Formation deposition characterized by alluvial fan aggradation rapidly filled the graben between the Consuelo and Carrizal faults as the Consuelo Fault underwent strain hardening and confining. In doing so, the sediment input by the active alluvial fan complex spilled over the Carrizal Fault displaying down lapping and progradation along the hanging wall. Its listric behavior on other hand, set off the tilting of the pre-extensional Paleogene sequences, which in turn caused the onlapping and diachronous deposition of the Zapotal Formation toward the La Cruz Fault. Protracted marine incursion and deposition of a fine grained siliciclastic sequence that encompassed the whole Oligocene took place around the already opened basin toward the south.Early Miocene breakup of the Farallon Plate not only increased the convergence rate but also gradually changed the convergence from oblique to orthogonal. Multiple intraformational unconformities and high sedimentation and subsidence rates in the Dos Bocas Formation documented this change. Recurrent deposition of the diatomaceous Villingota Formation suggested episodic upwelling in the basin enriched by the high siliceous tuffs supply from the coeval Saraguro Arc volcanism in the Western Cordillera. Basin transtension terminated during Late Miocene inception of the Rodeo and Playas synthetic Riedels to the reactivated Pallatanga Suture known as the dextral Chingual-Cosanga-Pallatanga-Puna (CCPP) fault system. However, as this fault continued into the Gulf of Guayaquil, the transtension was transferred to this area. Hitherto, the Progreso Basin underwent a sagging phase characterized by the onlapping of the Subibaja and Progreso formations against the La Cruz Fault High as well as a localized, subtle tectonic inversion due to space problems linked to the synthetic Riedels inception.

Reconstructing lost plates of the Panthalassa Ocean through paleomagnetic data from circum-Pacific accretionary orogens

The Panthalassa Ocean, which surrounded the late Paleozoic-early Mesozoic Pangea supercontinent, was underlain by multiple tectonic plates that have since been lost to subduction. In this study, we develop an approach to reconstruct plate motions of this subducted lithosphere utilizing paleomagnetic data from accreted Ocean Plate Stratigraphy (OPS). We first establish the boundaries of the Panthalassa domain by using available Indo-Atlantic plate reconstructions and restorations of complex plate boundary deformation at circum-Panthalassa trenches. We reconstruct the Pacific Plate and its conjugates, the Farallon, Phoenix, and Izanagi plates, back to 190 Ma using marine magnetic anomaly records of the modern Pacific. Then, we present new and review published paleomagnetic data from OPS exposed in the accretionary complexes of Cedros Island (Mexico), the Santa Elena Peninsula (Costa Rica), the North Island of New Zealand, and Japan. These data provide paleolatitudinal plate motion components of the Farallon, Phoenix and Izanagi plates, and constrain the trajectories of these plates from their spreading ridges towards the trenches in which they subducted. For 83 to 150 Ma, we use two independent mantle frames to connect the Panthalassa plate system to the Indo-Atlantic plate system and test the feasibility of this approach with the paleomagnetic data. For times prior to 150 Ma, and as far back as Permian time, we reconstruct relative and absolute Panthalassa plate motions such that divergence is maintained between the Izanagi, Farallon and Phoenix plates, convergence is maintained with Pangean continental margins in Japan, Mexico and New Zealand, and paleomagnetic constraints are met. The reconstruction approach developed here enables data-based reconstruction of oceanic plates and plate boundaries in the absence of marine magnetic anomaly data or mantle reference frames, using Ocean Plate Stratigraphy, paleo-magnetism, and constraints on the nature of circum-oceanic plate boundaries. Such an approach is a crucial next step towards quantitative reconstruction of the currently largely unknown tectonic evolution of the Earth9s oceanic domains in deep geological time.

A thyasirid-dominated methane-seep deposit from Montañita, southwestern Ecuador, from the Oligocene-Miocene boundary

A mass occurrence of the thyasirid bivalve Thyasira montanita in a limestone bed, exposed at Punta Montañita on the northern side of the Santa Elena peninsula in southeastern Ecuador, is here identified as an ancient methane-seep deposit. The massive to nodular limestone shows carbonate phases and microfabrics typical of seep limestones, such as banded and botryoidal cements. Its δ13Ccarbonate values, as low as −52.6‰, suggest a biogenic methane source. Furthermore, the carbonate microfabrics and biomarkers typical of ANME-2 archaea indicate high seepage rates. Tubular fossils previously interpreted as worm tubes show cone-shaped projections and an internal structure consistent with that of crustacean cuticle and are here interpreted as crustacean fragments. Seep deposits with mass occurrences of thyasirid bivalves have so far only been reported from the Cretaceous, making the Montañita seep deposit the first such example from the Cenozoic. The faunal and biomarker inventories of this deposit indicate deposition on an open shelf; the oysters on the upper surface of the limestone are likely secondary encrusters that arrived only after the emergence of this deposit in shallower water.

Reef environments of Murciélago Islands and Santa Elena peninsula, Guanacaste conservation area, Costa Rican pacific

The ecology of the marine environments of the Murciélago Islands and the Santa Elena Peninsula have been studied little despite their high biodiversity. This area is influenced by a coastal upwelling. In 2014, 2016 and 2018, the region was visited to assess the composition and diversity of its reef environments. Bottom coverage, macroinvertebrate diversity and abundance, and reef fish biomass were quantified. The substrate was dominated by turf and crustose calcareous algae. Live coral coverage has decreased compared to previous reports for the area. Sea urchins were the macroinvertebrates with the highest densities, while species of commercial interest presented low densities, this may suggest some degree of fishing pressure. 84 reef fish species were identified, making the islands area with the greatest diversity of reef fish in the North Pacific of Costa Rica. Coral biotopes in this region are key to the conservation of connectivity between reef areas due to their high diversity.

FORAMINÍFEROS PLANCTÓNICOS VIVOS EN EL MAR ECUATORIANO: TAXONOMÍA Y DISTRIBUCIÓN*

The sensitivity to changes of the environment marine of planktonic species, such as planktonic foraminifera, makes them in detection tools of marine ecosystem changes, at any given time. The principal purpose of this paper is about of taxonomy and distribution of planktonic foraminifera species found in the Ecuadorian sea, since 1973 until 1998. Zooplankton samples were collected aboard oceanographic cruises realized between the mainland coast until 92 °W, to west of Galapagos Islands,and in the fxed station “La Libertad” (Santa Elena Peninsula). The total population of planktonic foraminifera comprised 25 species distributed in three families and seven genera: Globigerina,Globigerinoides, Globoquadrina, Globorotalia, Orbulina, Hastigerina and Globigerinita. Of these, Globigerinoides sacculifer and G. ruber predominated in waters with major in?uence of warm waters of the Panama Bay and, Globigerina bulloides in cold waters of the Humboldt Current. G. sacculiferand G. ruber predominated during the event “El Niño” 97-98 all along the Ecuadorian coast

Identificación de parásitos gastrointestinales predominantes en bovinos de la Península de Santa Elena

La investigación se realizó en el Centro de Faenamiento Regional del cantón La Libertad, provincia de Santa Elena; el objetivo fue identificar la presencia o ausencia y tipos de parásitos gastrointestinales que se encuentran en los bovinos, para el estudio se utilizó la técnica coproparasitaria de flotación por sacarosa-glucosa y de frotis directo, la toma de muestras fecales se realizó en cincuenta animales post-mortem seleccionando aquellos provenientes de la zona peninsular, se tomó una muestra de heces, se identificó y conservó hasta su posterior análisis en el laboratorio de investigaciones agropecuarias de la Facultad de Ciencias Agrarias de la Universidad Estatal Península de Santa Elena, los resultados obtenidos se procesaron en el paquete estadístico SPSS 21.0. En los resultados se observó principalmente, parásitos gastrointestinales predominando los Nematodos con 87%, Cestodos 9% y quistes de Protozoos 4%; en donde la mayor presencia de los diferentes tipos de parásitos fueron Oesophagostomun spp (Nematodos) con 31%, Moniezia expansa 50% (cestodos) y Balantidium coli (protozoo) con 43%, cabe recalcar que, el método más eficiente en las condiciones para este estudio empleado fue el de la técnica de flotación con sacarosa en el cual se obtuvo un 55% de carga parasitaria en comparación con la de glucosa 35% y con el directo un 10%. Los resultados indican que, de acuerdo con los parámetros establecidos, es necesario realizar un plan sanitario en las diferentes zonas de la Península de Santa Elena para determinar los principales antiparasitarios que se deben utilizar para contrarrestar los nematodos, cestodos y protozoos dentro del tracto digestivo del bovino y poder bajar su presencia en la zona, mejorando el comportamiento productivo de los animales.

Análisis de los productos turísticos: caso Península de Santa Elena, Ecuador

The Santa Elena Peninsula (PSE as peer abbreviation in Spanish) is a coastal tourist destination in Ecuador. It has a variety of attractions that have not been fully analyzed as tourist products. It needs analysis and evaluation, in as much as it is a part of the "Coast World" destination that is promoted by the country at international markets. The research has a qualitative focus; it uses secondary sources as well as the SWOT analysis tool. This tool permits distinguishing variables that define the tourism product portfolio which is offered by the Santa Elena Peninsula. It is concluded that it is difficult to avoid typecasting the PSE as a Sun and Beach destination. This makes it hard to adapt new tourism products; there is but poor publicity management and low natural and cultural resource valuation; tourism product structuring is inadequate, which affects new market search.

Metodologías participativas en las prácticas pre-profesionales de la Carrera Gestión Social y Desarrollo de la Universidad Estatal Península de Santa Elena.

El propósito de este trabajo es presentar los resultados obtenidos del proceso de construcción del modelo de gestión de las prácticas pre-profesionales de la carrera de Gestión Social y Desarrollo de la Universidad Península de Santa Elena, en el que se incorporan metodologías participativas, que parten de la investigación-acción como su base teórica que genera fortalezas en todos los actores con quienes se trabaja encaminadas a una articulación, compromiso y transformación social, sobre todo en los países empobrecidos. Se involucró a los actores de la academia (Vicerrectorado Académico, Decanato, Dirección de la Carrera, docentes de la Carrera, estudiantes y personal administrativo). Las metodologías participativas que se aplicaron son: ficha descriptiva de información, deriva o transecto, entrevista semi-estructurada, taller, mapeo de actores y sociograma. Las conclusiones más representativas revelaron que las metodologías participativas permiten implementar la investigación-acción participativa; desde una visión de construcción colectiva, se establece una relación sujeto-sujeto para un aprendizaje de doble vía, (academia-sociedad). Desde la academia se permite articular las funciones sustantivas: docencia, investigación y vinculación. Desde la sociedad se cuenta con metodologías que posibilitan la solución de problemas y necesidades para transformar la realidad.

Geosites and Georesources to Foster Geotourism in Communities: Case Study of the Santa Elena Peninsula Geopark Project in Ecuador

Santa Elena Peninsula is characterized by beautiful geological features, historical geoscientific knowledge, and mineral and tourism resources that could all be combined for the sake of community development. This article provides an overview of the Santa Elena Peninsula Geopark Project through the assessment of six areas that are considered by inhabitants and researchers possible geosites to foster geotourism. The methodology included: (i) a technical description and assessment of the areas of interest evaluating their geological relevance, representativeness, geotouristic prominence, geotouristic scientific interpretation, and conservation criteria; (ii) an assessment through questionnaires carried out on inhabitants; and (iii) a SWOT Plus analysis to propose strategies for promoting geotourism. Results show that the areas of interest are highly valued as geosites, since they integrate geodiversity, biodiversity, and sociocultural aspects. For example, Ancon is a historical icon of early oil exploitation, Baños de San Vicente is a natural spring of thermal water and mud volcano, and Anconcito has bituminous exudations of natural occurrence together with a spectacular landscape produced by erosion. Overall, 90% of these sites were proved to be of high and very high interest in scientific terms. Geotourism is believed to be beneficial for the inhabitants of the Santa Elena Peninsula with respect to education, valorization of resources, and the strengthening of cultural identity of communities.

Distribución espacial, estructura social y amenazas de conservación de una pequeña comunidad de delfines nariz de botella, Tursiops trunca (Odontoceti: Delphinidae) en Ecuador

Socio-ecological and conservation aspects of a small community of bottlenose dolphins Tursiops truncatus (Odontoceti: Delphinidae) in Santa Elena, Ecuador. A resident community of bottlenose dolphins (Tursiops truncatus) has been studied irregularly between 2005 and 2018 around the tip of the Santa Elena Peninsula, Ecuador (2°11'S, 81°0.7'W). Opportunistic sightings and systematic surveys from the beach and at sea from a boat were carried out along 40 km of coast, accounting for 917.2 km of tracking by car from land and 707.4 km of boat tracking by sea. Average group size was 5.31 dolphins/group (SD= 1.97, range 1-10), with no significant changes throughout the study period. From land, however, the group size was underestimated 32% on the average. This small dolphin community currently has only nine individuals, including six adults, one immature and two calves. The relative abundance ranged between 0.03 dolphins/km in the northwestern part and 0.32 dolphins/km in the south, where dolphins concentrate their activities, possibly because human activities are less intense. Dolphins were generally distributed in the first 200 m from the shore, reaching up to 1,200 in the northern shallower part and where port and tourist activities concentrate. The dolphins’ speed was significantly higher when they were followed from a boat at close range (5.87 km/h) than when they were monitored from the beach (2.9 km/h) (P < 0.01), which suggests that boat tracking had an effect on dolphin´s movements. Pairwise cluster analysis showed that animals from this community show high rates of association among each other (average 0.67, range 0.01-1.0), indicating this is highly cohesive population unit. Dolphins also showed high level of residence (average occurrence index = 0.62). During the study, two main threats were identified, a gillnet fishery in the southwestern part and an intense fishing boat traffic in the northwestern. This coastal bottlenose dolphin community is the smallest of this species ever reported in the Gulf of Guayaquil, probably is a remnant of a larger population that would be in process of extinction. Most of the study area is currently part of a coastal-marine protected area created in 2008, which offers an opportunity for the recovery and conservation of this dolphin community. Given the fragility of this population unit, we recommend to environment authorities addressing potential threats by eliminating gillnets, implementing an exclusion zone for fishing gear and fishing boat traffic of 1 km width from the shore and limit the speed of any type of vessel to 10 knots within the reserve.

Spatial and temporal spatfall of the winged Pearl Oyster Pteria sterna (Gould, 1851), in Equatorial Coasts

The aim of the present study was to determine the spatial and temporal spatfall of the winged pearl oyster Pteria sterna in three different synthetic collectors (green mesh bags + mesh fence and mosquito net), deployed at three depths (2, 4 and 6 m). Samples from the bags were obtained over a period of 45 days, while environmental variables including chlorophyll a (Chl-a), oxygen, total particulate matter (TPM) and organic fraction (POM), salinity and temperature were measured each 3-week period. The study was conducted between November 2016 and October 2017 at El Palmar, Santa Elena Peninsula, Ecuador. Results showed significant differences in the spatial and temporal spatfall of the winged pearl oyster, with higher spatfall during November to early December 2016, followed by lower spat availability from later December to March 2017. A further increment of spatfall was observed from May–June and intensified for the last period of June–July 2017. The number of spat decreased during the following August–September and September–October periods. An ANOVA II analysis showed higher significant differences between deployment depths of collectors and the type of collector, as well as their interaction. Furthermore, Principal components analysis only showed a significant and negative relationship between spatfall and temperature, although results suggest that Chl-a may be a trigger that could induce oyster spawning events. Based on these results, possible strategies to improve the collection of the spat of winged pearl oyster P. sterna on the Ecuadorian coastline are discussed.