Anadara Tuberculosa Research Articles

Climate change drives spatiotemporal mismatches between bivalves and mangrove in the Colombian Pacific coast

The Piangua Anadara tuberculosa and Anadara similis are bivalve species thrive among mangrove roots and are crucial for vulnerable human communities, providing both economic and nutritional support. In the Colombian Pacific coast, significant efforts have been directed towards understanding the abundance and population structure of these mangrove bivalves. However, the impact of climate change on the spatiotemporal relationship between the potential distribution of these bivalves and their potential habitat, Rhizophora mangle, remains underexplored. We developed distinct Ecological Niche Models (ENMs) for both bivalve species and their potential habitat based on species presence-pseudo-absence data, soil physicochemical attributes, and bioclimatic variables projected for the present and future in the Colombian Pacific coast. The projections for 2030 and 2050 were formulated using the optimistic (Shared Socioeconomic Pathways –SSP1), intermediate (SSP2), and pessimistic (SSP5) climate change scenarios as proposed by the Intergovernmental Panel on Climate Change (IPCC) in its sixth report. Currently, there is a significant correlation between the potential distribution of the Piangua species and the mangroves on the Colombian Pacific coast. However, this relationship is expected to undergo spatiotemporal changes due to future climate shifts, especially by 2050 under the most pessimistic climate scenario (SSP5). Our findings offer valuable insights for the management and conservation of both the Piangua and the mangroves in the Colombian Pacific coast. Conservation efforts for the Piangua species should prioritize areas that are likely to remain suitable for both the species and its associated habitat, the mangroves.

Biological and economic feasibility of cultivating the mangrove cockle Anadara tuberculosa (Sowerby, 1833) in a shrimp farm reservoir with estuarine influence in Santa Elena, Ecuador

The extraction of Anadara tuberculosa, a commercially valuable species in the tropical Eastern Pacific mangroves, presents significant ecological risks. To mitigate these risks, captive production of A. tuberculosa is crucial. This study examines the somatic conditions of laboratory-produced A. tuberculosa spat and their cultivation on a pilot scale in a canal-reservoir of a shrimp farm. Spat measuring 6.2 ± 0.9 mm were placed in baskets and cultured in suspension at a density of 776.6 ± 26.0 cockles (0.54 cockle per square centimeter). Environmental variables at the culture site were monitored. After 24 months of culture, the cockles reached a size of 44.7 ± 0.6 mm with a survival rate of 65.0 ± 0.6%. These production results were extrapolated to evaluate the economic viability of production in a shrimp farm canal-reservoir with estuarine influence. The proposed economic model yielded 325,000 market-ready Anadara tuberculosa mangrove cockles (in five culture cycles) with an estimated net present value (NPV) of $22,914.00. The modified internal rate of return (MIRR) reached 15.20 percent, and the cost-benefit ratio was $1.96. Economic projections indicate that the initial capital investment could be recovered within five years and one month (payback). This research provides evidence of the biological feasibility, including somatic growth, survival rates, and the relationship with environmental variables at the site, as well as the economic feasibility of cultivating A. tuberculosa in a canal of a shrimp farm with estuarine influence. The findings offer valuable insights for scaling up aquaculture production and initiating restoration processes for this species.

Quantification of Heavy Metal Content in Anadara tuberculosa from the Gulf of Guayaquil Using ICP-OES: Assessing Marine Contamination

The present study was conducted to quantify the heavy metals cadmium, lead, copper, chromium, nickel, and zinc in the bivalve mollusk concha prieta (Anadara tuberculosa) using inductively coupled plasma optical emission spectroscopy (ICP-OES). This research aims to identify whether the bioaccumulated content of heavy metals exceeds the maximum limits established by various public health bodies such as the ONU, FAO, Codex Alimentarius, EEC, and NHI. Samples of the species were collected randomly from three locations in Puerto El Morro, Playas Municipal Market, and La Libertad Seafood Market in the Gulf of Guayaquil. Thirty-three soft tissue samples of Anadara tuberculosa were evaluated, and the values quantified in mg/kg were in the following order: Zn > Cu > Cd > Ni > Cr > Pb.

Unveiling potential virulence determinants in Vibrio isolates from Anadara tuberculosa through whole genome analyses.

The genus Vibrio includes pathogenic bacteria able to cause disease in humans and aquatic organisms, leading to disease outbreaks and significant economic losses in the fishery industry. Despite much work on Vibrio in several marine organisms, no specific studies have been conducted on Anadara tuberculosa. This is a commercially important bivalve species, known as "piangua hembra," along Colombia's Pacific coast. Therefore, this study aimed to identify and characterize the genomes of Vibrio isolates obtained from A. tuberculosa. Bacterial isolates were obtained from 14 A. tuberculosa specimens collected from two locations along the Colombian Pacific coast, of which 17 strains were identified as Vibrio: V. parahaemolyticus (n = 12), V. alginolyticus (n = 3), V. fluvialis (n = 1), and V. natriegens (n = 1). Whole genome sequence of these isolates was done using Oxford Nanopore Technologies (ONT). The analysis revealed the presence of genes conferring resistance to β-lactams, tetracyclines, chloramphenicol, and macrolides, indicating potential resistance to these antimicrobial agents. Genes associated with virulence were also found, suggesting the potential pathogenicity of these Vibrio isolates, as well as genes for Type III Secretion Systems (T3SS) and Type VI Secretion Systems (T6SS), which play crucial roles in delivering virulence factors and in interbacterial competition. This study represents the first genomic analysis of bacteria within A. tuberculosa, shedding light on Vibrio genetic factors and contributing to a comprehensive understanding of the pathogenic potential of these Vibrio isolates.IMPORTANCEThis study presents the first comprehensive report on the whole genome analysis of Vibrio isolates obtained from Anadara tuberculosa, a bivalve species of great significance for social and economic matters on the Pacific coast of Colombia. Research findings have significant implications for the field, as they provide crucial information on the genetic factors and possible pathogenicity of Vibrio isolates associated with A. tuberculosa. The identification of antimicrobial resistance genes and virulence factors within these isolates emphasizes the potential risks they pose to both human and animal health. Furthermore, the presence of genes associated with Type III and Type VI Secretion Systems suggests their critical role in virulence and interbacterial competition. Understanding the genetic factors that contribute to Vibrio bacterial virulence and survival strategies within their ecological niche is of utmost importance for the effective prevention and management of diseases in aquaculture practices.

Estimation of Growth and Size at First Maturity under a Multimodel Approach of Anadara tuberculosa (Sowerby, 1833) on the Southeast Coast of the Gulf of California

The clam fishery in northwestern Mexico encompasses the mangrove cockle Anadara tuberculosa. It is extracted manually, at low tides and between the roots of mangroves. Biological samplings were carried out in Estero Las Lajitas, Sinaloa, from May 2021 to April 2022. A total of 661 A. tuberculosa organisms were analyzed, of which 126 were males, were 363 females and 172 were undifferentiated, yielding a statistically different overall sex ratio between females and males (1♀:0.3♂) (X2 = 113.19; p < 0.05). The length–weight relationship showed a potential type (W = 0.0002L3.125) (95% CI 3.027–3.222 for b). To determine the growth of the species, five models were employed: von Bertalanffy, Gompertz, Logistic, Richards, and Gompertz using an oscillatory component (GO). The Akaike Corrected Information Index for Small Samples (AICC) was used. The GO model yielded the lowest AICC (L∞ = 80.98 mm 95% CI 77.59–84.36, k = 1.02 year−1 95% CI 0.89–1.16), a low growth oscillation intensity (C = 0.03), and slower growth in August (WP = 1.67). The Logistic and Gompertz models were used to calculate the size-at-maturity (L50%). Gompertz obtained the lowest AICC with L50% = 32.53 mm (95% CI 30.67–34.31). Considering the lack of biological information and the parameters generated in the present investigation, as regards A. tuberculosa on the coast of Sinaloa, Mexico, its dissemination is essential for the adequate management of the fishery.

Human health risk assessment for consumption of microplastics and plasticizing substances through marine species

A special characteristic of MP (microplastics) in the ocean is they may act as carriers of additives specific to the plastic materials used in their manufacture, such as plasticizers, among which Bisphenol-A (BPA), bis (2-ethylhexyl) phthalate (DEHP), dybuthyl phthalate (DBP). Both MP as the plasticizers were searched in composite samples of mangrove cockle (Anadara tuberculosa), Stolzmann's weakfish (Cynoscion stolzmanni) and arched swimming crab (Callinectes arcuatus). Extraction of MP was done through physical-chemical techniques and identification was carried out employing the techniques of light microscopy, energy dispersive spectrometer (EDS), scanning electron microscope (SEM) and Raman spectroscopy; the sizes of MP obtained were between 0.5 μm and 106 μm, the following average results being obtained: for Arched swimming crab 4.0 ± 1.0 MP/g; mangrove cockle 3.3 ± 2.9 MP/g; and for Stolzmann's weakfish, the average was 2.4 ± 1.3 MP/g; the most observed shapes were fibers and irregular segments; the most identified MP was polyethylene terephthalate (PET). Regarding extraction and quantification of plasticizers, the extraction stage was carried out using QuEChERS tubes; and the identification and quantification with gas chromatography coupled to a mass spectrometer (GC-MS). Regarding the plasticizing substances, DEHP was found in detectable levels in all the samples; BPA was found in 84% of the composite samples analyzed; DBP was found in 50% of them, of the analyzed samples 34% were positive for the 3 analytes. The dietary exposure of people to plasticizers was calculated and for BPA the exposure obtained was compared with respect to the TDI (tolerable intake dose) for pregnant women and the new TDI proposed by EFSA in 2021 according to the estrogenic effect of this substance in the fetus. The objective of the work was to determine if a relationship could be established between both PM and plasticizers, which gave a positive relationship.

Ideal settlement substrate and effect of darkness on spat production of the mangrove cockle Anadara tuberculosa

The mangrove cockle (Anadara tuberculosa) is considered overharvested. Therefore, its spat production in hatchery is needed for aquaculture and restocking of natural banks. However, larval settlement and metamorphosis are critical phases that need to be further explored. The use of different substrates on the settlement and two photoperiods on spat production of A. tuberculosa were evaluated. Furthermore, its embryonic development is described. In the first experiment, the settlement and survival of pediveliger larvae distributed in a completely dark experimental system provided with different diameters natural substrates: sand (≤500 μm), sand (≤200 μm), crushed shells of A. tuberculosa (≤200 μm), a mixture of sand and crushed shells of A. tuberculosa (≤200 μm), not-crushed shells of A. tuberculosa (5–10 mm), and nylon mesh (150 μm mesh size) were compared. In a second experiment, metamorphosed postlarvae were placed under 12 h light and 12 h dark (12 L: 12D) versus 0 h light and 24 h dark (0 L: 24D), to compare survival and growth. Additionally, a culture cycle from early larval stages until spat production under dark conditions was exanimated and described. The mesh base resulted the best substrate for a fast settlement and high larval survival. The photoperiod 0 L:24D enhanced spat growth compared to 12 L:12D. The average growth rate for shell height was 11.43 μm d−1 in the larval phase and 23.71 μm d−1 during postlarval phase. After metamorphosis, the larval growth increased rapidly until spat. A dark period and nylon mesh substrate should be considered as a preponderant factor in the massive spat production of A. tuberculosa.

Assessment of mercury and lead contamination using the bivalve Anadara tuberculosa (Arcidae) in an estuary of the Colombian Pacific

Buenaventura Bay is considered the main estuary on the Pacific coast of Colombia, because of port and industrial activities. Mining and agriculture are major sources of contamination in the estuary. This study used the bivalve Anadara tuberculosa to evaluate the presence of mercury and lead in the Dagua River estuary (Colombia), one of the main tributaries coming into the bay. Five samplings for sediments and six for tissues of A. tuberculosa were carried out between 2016 and 2017. Additionally, a series of bioassays were conducted to determine its ability to bioaccumulate metals. A mean mercury concentration of 0.57 ± 0.74 mg*kg−1 and lead concentration of 0.87 ± 0.68 mg*kg−1 in sediment were found. Bioassays allowed us to conclude that at low mercury exposure concentrations (0.25 mg*kg−1), lesions are generated in animal tissue, mainly in sexual cells. The high concentrations of mercury found in organisms exceed the maximum permitted concentration established in Colombia. In addition, the contamination factors for mercury and lead were considered very high. This research aims at contributing to the use of Anadara tuberculosa, as prospective bioindicator for pollution biomonitoring in mangrove coastal ecosystems.

Total mercury determination in bivalves Anadara tuberculosa sold in open markets from Quito, Ecuador

This study aimed to quantify the amount of total mercury in bivalves Anadara tuberculosa supplied from Esmeraldas Province and sold in markets in the Metropolitan District of Quito, Ecuador. The determined total mercury concentration was compared to the permissible limits established by the European Commission and World Health Organization-Food and Agriculture Organization and health risk subsequently assessed. Sampling was conducted in five open markets and involved collecting fifteen specimens from each market. Total mercury was measured through cold vapor atomic fluorescence spectrophotometry. Results showed that samples did not exceed the total mercury threshold value (0.5 mg kg−1). However, samples of Anadara tuberculosa from the Ofelia market, which receives fresh products from Eloy Alfaro canton, contained the highest mean levels of mercury contamination, 0.055 mg kg−1. This result could be associated to the influence of illegal mining activity in this area. In addition, methylmercury potential non-carcinogenic risk for consumers exceeded the threshold limit (>1) established by the US Environmental Protection Agency. The daily consumption rate (Rclim) was determined to be 26.61–38.50 g for a child weight of 14.5 kg, and 128.44–185.84 g for an adult weight of 70 kg. Thus, consuming a higher amount of Anadara tuberculosa could negatively affect human health.

RETRACTED ARTICLE: Toward a characterization of Ecuadorian ceviche: much more than shrimp

Ceviche is present in all the Pacific coast of Latin America. Its origin and history are still debated. The consensus is that it arises from creolization between local and Eurasian ingredients and techniques. Ecuadorian ceviche is both traditional and iconic, present in one form or another in its twenty-four provinces, adapting to the availability of products and becoming part of the identity of regions, parishes, and cities. The objective of this work is to confirm ceviche as a traditional Ecuadorian dish, to assess the most popular types of Ecuadorian ceviche, condiments and sides, and also to glimpse the wide variety of preparations that appear through adaptation to ingredient availability and food customs. We performed a review of both scientific and gray literature, a relative search volume analysis and a survey among culinary professionals (n = 403). The most popular in Ecuador is shrimp (Litopenaeus vannamei) ceviche with 54% of the responses, followed by fish, regardless of species (29%), and both lupin (Lupinus mutabilis) and black clam (Anadara tuberculosa) with 5%. The most utilized condiments are onion, lemon juice and cilantro a “holy trinity” with more than 90% usage. These results are in good agreement with those provided by Web search volumes. The variety of main ingredients, condiments and sides is ample, though, and suggests further research. Sustainability concerns related to ceviche are the sustainability of shrimp farming and fish capture, and the preservation of mollusks and their ecosystems.

Rotavirus in Oysters, Lettuce, and Feces in Children with Diarrhea from Panama

Rotavirus infections are the most common causes of infectious diarrhea in young children worldwide. We performed a genotyping of rotavirus strains by RT-PCR for G (VP7) and P (VP4), in Anadara tuberculosa, Lactuca sativa and feces samples of children with diarrhea collected in Panama. Combinations of genotypes G (VP7) and P (VP4) were identified in Anadara tuberculosa: 30 (15%) corresponding to G12P[8], 26 (13%) to G12P[6], 28 (14%) to G1P[8], 7 (3.5%) to G2P [6]. Lactuca sativa: 42 (18%) corresponding to G12P[8], 33 (14%) to G1P[8]. In feces of children with diarrhea: 39 (13%) corresponding to G12P[8], 14 (4.6%) to G9P[8], 12 (4%) to G12P[6], 2 (0.6%) to G2P[x], 1(0.3%) to G3P[8], 6(2%) to G2P[4] were identified. This research represents the first report of rotavirus strains identified in Anadara tuberculosa and Lactuca sativa in Panama and the Central American region.

Early life cycle description and effects of microalgal diets on larval and post‐larval development of the mangrove cockleAnadara tuberculosa(Sowerby, 1833)

Natural populations of the edible mangrove cockle (Anadara tuberculosa) are threatened by overexploitation and environmental degradation due to anthropogenic activities. The indoor production of larvae and early spat of mangrove cockles requires knowledge regarding the evolutionary characteristics of their larval morphology, associated with the appropriate use of microalgae. Therefore, we describe the larval and early post-larval development of A. tuberculosa raised in the laboratory and the effect of six microalgae on its growth and survival. Additionally, microalgae ingestion–digestion was determined using epifluorescence microscopy, and the fatty acid profile of the microalgae was analysed. Microscopic observations indicated the presence of D veliger larvae 18 h post fertilization, and the first batch of spat was obtained after 45 days of culture. The spat reached a manoeuvrable size at 90 days post fertilization (3 mm). Best shell lengths of oculated larvae (157.62 and 172.47 µm), daily growth rates (4.77 and 4.52 µm/day), survivals (30% and 23%) and settlement rates (23% and 11%) were obtained with the diatoms Chaetoceros gracilis and Chaetoceros muelleri respectively. Diets Tetraselmis chuii, Thalassiosira sp. and Pavlova lutheri, despite being ingested–digested, did not result in oculated larvae, which possibly indicates an inadequate lipid content for A. tuberculosa larvae culture. Larvae seem to have a high nutritional requirement for myristic acid, palmitoleic acid, hexadecadienoic acid, stearic acid and eicosapentaenoic acid. Our findings show the feasibility of producing spat in captivity, which contributes to promoting its production and thereby developing ecological restoration plans and/or diversifying aquaculture in Ecuador.

Performance and Challenges in the Value Chain of the Anadara tuberculosa Bivalve Mollusk in Ecuador

The bivalve mollusk, Anadara tuberculosa (Black Shell, in Spanish Concha Prieta), is found on America’s Pacific coast, where it is harvested for subsistence and commercial markets. This paper aims to diagnose the performance of the black shell’s value chain. We also identify several challenges that must be addressed to improve the sustainability of the black shell fishery in Ecuador. The applied methodology was quantitative and descriptive. Its design was non-experimental, field, cross-sectional and ex post facto. The investigation was carried out from January to October 2019 in the Jambelí archipelago, El Oro province, Ecuador. The study population consisted of 565 individuals, shellfish collectors, shellfish associations managers, traders, and restaurants from the A. tuberculosa production chain. The sample size was estimated at 222 informants. The type of sampling used was probabilistic, random, stratified, and with proportional allocation, with an effective participation rate of those selected of approximately 80%. The questionnaire was applied personally through the structured survey method, in writing, in the work area, and with their consent. The performance of the value chain was diagnosed in the dimensions of productivity, competitiveness, and quality of life, reaching a 75.1% index, a result that indicates that the value chain has a moderate to good performance level. The competitiveness dimension reached the highest performance, followed by productivity. Quality of life was the dimension with the lowest performance. The value chain can be improved if the following challenges are met: (1) Restoration of the mangrove ecosystem, (2) Promotion of low-intensity shellfish aquaculture, (3) Good sanitary management and purification, (4) Promotion of value-focused ventures, (5) Strengthening of organizations and agreements for the use and custody of mangroves, and (6) Strengthening of institutions that contribute to the advancement of these challenges.

Structural Equations Model of the Concha Prieta (Anadara tuberculosa) Agribusiness Management and Value Chain Performance in the Ecuadorian Mangroves

Mangroves are tropical and sub-tropical ecosystems that fulfill multiple beneficial functions for preserving life on the planet and the economic support of families living in their surroundings. Such is the case of the mangroves in Ecuador, in which the Concha Prieta (Anadara tuberculosa) is produced through the manual extraction of natural populations. However, this production system is threatened by deforestation and overexploitation. This research aims to formulate an agribusiness management model that impacts the A. tuberculosa's value chain performance levels using as validation tools the structural equations model. A non-experimental, cross-sectional, and ex-post-facto field research methodology was applied. The population under study was made up of the production chain participants, through a representative sample of 138 shellfish collectors, 12 managers of shellfish associations, 27 merchants, and 45 restaurants. The study was carried out in the Jambeli archipelago, in El Oro province, Ecuador, in 2019. Likewise, a questionnaire for each stage of the research was designed and validated through experts' judgment. The collected data were processed and analyzed through the structural equations model, using SPSS and AMOS software. The result obtained shows an interdependence relationship between both latent variables, with a covariance index of 0.45, which allows us to infer that as the processes integrated into Agribusiness Management are improved, higher levels are reached in the Performance components of the mollusk value chain and vice-versa. In particular, the exogenous variable Agribusiness Management is related to the endogenous variables mentioned below, with their respective factorial load: Evaluation (0.72); Process innovation (0.69); Internal factors of innovation (0.67); Planning (0.65); Execution (0.58) and External factors of innovation (0.38). Likewise, the exogenous variable Value Chain Performance is related to the endogenous variables mentioned below and their respective factorial load: Physical productivity (0.86); Economic productivity (0.83); Percentage indicator of net income (0.35); Operational profitability (0.21); Quality of life (-0.07) and Leadership in costs (-0.06). We conclude that the Agribusiness Management and Value Chain Performance constructs are interdependent and that the Physical Productivity and Evaluation indicators are the ones that have the most significant influence on this relationship. We recommend simulating these effects and relationships to propose improvement strategies to the said value chain.

An Overview of Cadmium, Chromium, and Lead Content in Bivalves Consumed by the Community of Santa Rosa Island (Ecuador) and Its Health Risk Assessment

Santa Rosa Island community members derive their income and livelihoods from bio-aquatic resources, principally bivalves of the genus Anadara, both for subsistence use and commercial purposes. Bivalve mollusks have a sedentary lifestyle and feed by filtering water, meaning they absorb all surrounding substances, including harmful elements like toxic metals. This study aimed to analyze different-sized samples of Anadara tuberculosa and Anadara similis, sediment, and Rhizophora mangle leaves to determine their total amount of cadmium, lead, and chromium as a first approach to the evaluation of the health risk related to the consumption of bivalves. For both species from four sampling sites, the results revealed metal concentrations in the bivalves between 0.211 and 0.948 mg·kg-1, 0.038 and 0.730 mg·kg-1, and 0.067 and 0.923 mg·kg-1 for Cd, Cr, and Pb, respectively. The calculated potential risk (>1) for cadmium, considering all body weights, showed a high health risk for consumers. In the case of lead, the results showed a high health risk in children. There was no risk found for chromium. For sediments, the mean values were 2.14, 29.99, and 12.37 mg·kg-1 and for the Rhizophora mangle leaves were 2.23, 4.22, and 3.35 mg·kg-1 for Cd, Cr, and Pb, respectively. These results did not show a relation with the metal content in bivalves.

An overview of cadmium, chromium, and lead content in bivalves consumed by the community of Santa Rosa Island (Ecuador) and its health risk assessment

Santa Rosa Island community members derive their income and livelihoods from bio-aquatic resources, principally bivalves of the genus Anadara, both for subsistence use and commercial purposes. Bivalve mollusks have a sedentary lifestyle and feed by filtering water, meaning they absorb all surrounding substances, including harmful elements like toxic metals. This study aimed to analyze different-sized samples of Anadara tuberculosa and Anadara similis, sediment, and Rhizophora mangle leaves to determine their total amount of cadmium, lead, and chromium as a first approach to the evaluation of the health risk related to the consumption of bivalves. For both species from four sampling sites, the results revealed metal concentrations in the bivalves between 0.211 and 0.948 mg·kg-1, 0.038 and 0.730 mg·kg-1, and 0.067 and 0.923 mg·kg-1 for Cd, Cr, and Pb, respectively. The calculated potential risk (>1) for cadmium, considering all body weights, showed a high health risk for consumers. In the case of lead, the results showed a high health risk in children. There was no risk found for chromium. For sediments, the mean values were 2.14, 29.99, and 12.37 mg·kg-1 and for the Rhizophora mangle leaves were 2.23, 4.22, and 3.35 mg·kg-1 for Cd, Cr, and Pb, respectively. These results did not show a relation with the metal content in bivalves.

Estimación del riesgo ecológico y a la salud humana del mercurio en una zona de manglar del estuario La Puntilla, provincia de El Oro, sur del Ecuador

El presente estudio se centra en la evaluación de los niveles de concentración de mercurio total y la estimación del riesgo ecológico (Er), el índice de riesgo ecológico (RI) y el coeficiente de riesgo tóxico o peligro (HQ) para la salud humana en un área de manglar junto a las desembocaduras de los ríos Chaguana y Siete, en el estuario de La Puntilla en el sur de Ecuador. Para la determinación de Er, RI y HQ, identificamos tres indicadores de contaminación por mercurio: sedimentos, raíz de mangle y tejido blando del bivalvo Anadara tuberculosa. En el área de manglar que bordea la desembocadura del río Chaguana, las concentraciones de mercurio fluctuaron entre 0,11±0,06 mg/kg en sedimentos, 0,06±0,01mg/kg en raíz de mangle, con una consistente presencia de A. tuberculosa, pero solo una muestra del bivalvo registró un nivel de 0,034 mg/kg de mercurio. En contraste, en el área de manglar adyacente a la desembocadura del río Siete, las concentraciones de mercurio oscilaron entre 0,77±0,42 mg/kg en sedimentos y 0,15±0,12 mg/kg en la raíz de manglar, siendo imperceptible la presencia de A. tuberculosa. Los resultados del análisis de riesgo indicaron que en la desembocadura del río Chaguana, el Er y el índice de RI se colocaron en la categoría “baja”. En contraste, en la desembocadura del río Siete, el Er resultó “alto” y RI resultó “moderado”. El riesgo potencial para la salud humana fue bajo, en consistencia con el valor de HQ < 1 que considera el consumo de A. tuberculosa y el contacto dérmico a través de sedimentos; sin embargo, la escasa presencia del bivalvo en la desembocadura del río Siete es de preocupación.

Importancia de la producción de la concha prieta (Anadara tuberculosa) en las costas ecuatorianas

La extracción de la concha prieta (Anadara tuberculosa) es una actividad productiva ancestral, que se realiza de manera espontánea e intuitiva y cuya importancia no ha sido suficientemente ponderada, destacada y reconocida en los diversos ámbitos gubernamentales, empresariales y académicos del Ecuador y de otros países que también la producen. Esta investigación tiene por objetivo indagar sobre los indicadores que determinan la importancia económica, social y ambiental a nivel global y nacional de la producción del molusco bivalvo concha prieta. A tal fin, se aplicó una metodología de investigación bibliográfica de fuentes primarias, secundarias y terciarias. Se obtuvo como resultado que su aporte al PIB ecuatoriano es de 15 millones de USD al año, si se incluye el valor que se agrega a la concha prieta a nivel de restaurante, picanterías y cevicherías, que genera unos 8000 puestos de trabajo de tiempo completo y parcial, la mayoría por cuenta propia. Contribuye a preservar más de 156 mil hectáreas de superficie de manglar existentes todavía en las costas ecuatorianas. Se concluye que la producción de la concha prieta registra una relevancia significativa en términos económicos, sociales y ambientales, con un gran potencial para insertarse de manera formal en el circuito exportador ecuatoriano, de mejorar los niveles de ingresos y calidad de vida de los concheros y de contribuir al manejo sostenible del ecosistema manglar. Se recomienda profundizar en el estudio de las variables económicas, sociales y ambientales que tienen mayor incidencia sobre sus niveles de sostenibilidad y competitividad.

Production of specific pathogen free larvae from genetically characterized populations of Anadara tuberculosa (Bivalvia), for stock enhancement and aquaculture in the Peru Northeast Biosphere Reserve

The pustulose ark, Anadara tuberculosa , is considered as an emblematic species of the east Pacific mangrove ecosystem. The decline of its populations is of increasing preoccupation, in particular in Peru. The use of hatchery-produced larvae for stock enhancement or aquaculture is attractive but raises strong criticisms from an ecological point of view, as it could conduce to loss of genetic diversity in wild populations and favor the disease spreading from hatcheries to the environment. In this works, spat production through traditional aquaculture/biotechnology technologies was associated with pathogen molecular diagnostics and with genetic diversity estimation to produce specific pathogen-free (SPF) larvae from genetically characterized populations. All PCR and nested-PCR diagnostics of common bivalve pathogens, such as Bonamia , Martelia , Perkinsus and OsHV1, led to negative results for healthy or moribund adults and spat samples. Microbiological and molecular analyses realized during mortalities led to identifying a pathogenic Pseudomonas strain present on culture tank walls, in moribund spats and adults´ blood. Population genetic variation was assessed by mitochondrial COI gene sequences which showed 36.7% haplotype diversity. This study with hatchery production, pathology and genetic components for an overexploited native bivalve represents an original model for successful mollusk stock enhancement or/and innovative aquaculture programs. Normal 0 21 false false false ES-EC X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabla normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri,sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-ansi-language:ES-MX; mso-fareast-language:ES-MX;}

Genetic structure, phylogeography, and demography of Anadara tuberculosa (Bivalvia) from East Pacific as revealed by mtDNA: Implications to conservation.

Wild populations of the pustulose ark, Anadara tuberculosa (Bivalvia), an emblematic species of the East Pacific mangrove ecosystem declined in South American countries (Colombia, Ecuador, and Peru) mainly due to overharvesting and habitat loss or degradation. Understanding the genetic aspects of geographic variations and population structure of A. tuberculosa, currently unknown, appears as a priority to fishery authorities in order to elaborate integrated and collaborative conservation policies for fishery management, aquaculture, and stock enhancement programs. We used mtDNA sequence data to investigate haplotype diversity, genetic structure, and demography of A. tuberculosa. Results indicate genetic homogeneity of populations distributed north and south of the equator, respectively. However, statistically significant differentiation emerged between northern and southern populations with pairwise ф ST values ranging between 0.036 and 0.092. The oceanic current system acting in the area (Panama Current and Humboldt Current) might play a role in limiting the larval dispersal of the species, still poorly understood. Demography reconstruction supported recent population expansion, possibly started after last glacial maximum. Our results would suggest separate and independent management of populations north and south of the equator.