Resumen (Objetivo). Se evaluó el manglar de Chacarita en el Pacífico Central de Costa Rica, a través de la composición florística y las poblaciones de moluscos asociados de interés comercial, con el fin de proponer actividades de aprovechamiento sustentables en el manglar. (Metodología). Mensualmente y durante un año, se realizaron visitas al área de estudio, con el propósito de establecer una base florística de árboles de mangle y medir el almacenamiento de carbono en el lugar, además, de recolectar moluscos bivalvos para analizar el estado de las poblaciones, con base en las abundancias de organismos hallados y otras características como las longitudes y la masa de estos. En los mangles, se obtuvo el diámetro de la altura de pecho (DAP en cm), la altura (m), el índice de valor de importancia (IVI) y las reservas de carbono (Mg C·ha-1). En cuanto a los moluscos, se examinaron cuatro especies de interés comercial, evaluando la longitud (cm), la masa (g) y el índice gonadosomático. Finalmente, se realizaron valoraciones económicas de los datos obtenidos en el manglar, del turismo e información histórica de pesca para el acopio de Chacarita. (Resultados). Se hallaron cinco especies de mangles, Rhizophora mangle, Rizophora racemosa, Laguncularia racemosa, Avicennia germinans y Pelliciera rhizophorae; P. rhizophorae fue la de mayor índice de valor de importancia. Se obtuvo un almacenamiento de carbono equivalente a 78.49 Mg C·ha-1. Se contabilizaron 357 organismos, de los cuales el 18 % correspondió a Anadara similis, 37.5 % a Anadara tuberculosa, 41.46 % a Leukoma spp. y 3.08 % a Mytella guyanensis. Tomando en cuenta el valor económico de las reservas de carbono y los moluscos bivalvos presentes en los muestreos, se obtuvieron valoraciones económicas de 9812.63 USD·ha-1 y 28 USD·ha-1, respectivamente. (Conclusiones). Las bajas densidades poblacionales de moluscos, especialmente del género Anadara, hacen necesario establecer medidas de gestión que permitan recuperar las poblaciones de estos. La presente investigación propone actividades de aprovechamiento sustentables, como turismo comunitario con fines educativos y culturales.

Resumo (Objetivo). O mangue de Chacarita, no Pacífico Central da Costa Rica, foi avaliado por meio da composição florística e das populações de moluscos associados de interesse comercial, com o objetivo de propor atividades de uso sustentável no mangue. (Metodologia). Foram feitas visitas mensais à área de estudo durante um ano para estabelecer uma base florística de árvores do mangue e medir o armazenamento de carbono no local, bem como para coletar moluscos bivalves para analisar o status das populações, com base na abundância de organismos encontrados e em outras características, como comprimento e massa de tais organismos. Nos manguezais, foram obtidos o diâmetro à altura do peito (DAP em cm), a altura (m), o índice de valor de importância (IVI) e as reservas de carbono (Mg C-ha-1). No que diz respeito aos moluscos, foram examinadas quatro espécies de interesse comercial., avaliando o comprimento (cm), a massa (g) e o índice gonadossomático. Por fim, foram feitas avaliações econômicas de dados de mangue, turismo e informações históricas de pesca para a coleção Chacarita. (Resultados). Foram encontradas cinco espécies de mangue, Rhizophora mangle, Rizophora racemosa, Laguncularia racemosa, Avicennia germinans e Pelliciera rhizophorae; a P. rhizophorae apresentou o índice de valor de importância mais alto. Foi obtido um armazenamento de carbono equivalente a 78.49 Mg C-ha-1. Foram calculados um total de 357 organismos, dos quais 18% correspondeu a Anadara similis, 37.5% Anadara tuberculosa, 41.46% Leukoma spp. e 3.08% Mytella guyanensis. Levando em conta o valor econômico das reservas de carbono e dos moluscos bivalves presentes nas amostras, foram obtidas avaliações econômicas de US$ 9812.63 ha-1 e US$ 28 ha-1, respectivamente. (Conclusões). As baixas densidades populacionais de moluscos, especialmente do gênero Anadara tornam necessário o estabelecimento de medidas de manejo para permitir a recuperação dessas populações. Esta pesquisa propõe atividades de uso sustentável, como o turismo comunitário para fins educacionais e culturais.

Abstract (Objective). The floristic composition and populations of associated molluscs of commercial interest of the Chacarita mangrove forest on the Central Pacific of Costa Rica were evaluated to guide proposals for sustainable exploitation activities in the mangrove forest. (Methodology). Monthly visits to the study area were conducted for one year to establish a floristic baseline of mangrove trees and measure carbon storage. Additionally, bivalve molluscs were collected to analyze the state of their populations based on the abundances of organisms found, as well as other characteristics such as length and mass. Data regarding the mangrove trees included their diameter at breast height (DBH, cm), height (m), importance value index (IVI), and carbon reserves (Mg C·ha-1). Four mollusc species of commercial interest were analyzed, using data on their length (cm), weight (g), and gonodosomatic index. Economic evaluations were also conducted using data obtained from the mangrove forest, as well as tourism and historical fishing data for the collection of Chacarita. (Results). Five species of mangroves were identified: Rhizophora mangle, Rizophora racemosa, Laguncularia racemosa, Avice germinans, and Pelliciera rhizophorae, while P. rhizophorae had the highest importance value index. The study revealed a carbon storage equivalent to 78.49 Mg C·ha-1. A total of 357 organisms were counted, with Anadara similis accounting for 18% of the total count, followed by Anadara tuberculosa (37.5%), Leukoma spp. (41.46%), and Mytella guyanensis (3.08%). When considering the economic value of carbon stocks and the bivalve molluscs obtained from the samples, economic valuations of 9,812.63 USD·ha-1 and 28 USD·ha-1 were determined, respectively. (Conclusions). The low population densities of molluscs, particularly those belonging to the Anadara genus, necessitate the establishment of management measures to facilitate the recovery of these mollusk populations. This research proposes sustainable use activities such as community tourism for educational and cultural purposes.

Resumen Se analizan 21 elementos de concha procedentes de distintos contextos arqueológicos del interior de la provincia de Santa Cruz, lo cual incrementa considerablemente la muestra existente para el sur de Patagonia. Se discuten sus características y distribución en relación con la información disponible respecto de las formas de aprovechamiento y circulación de valvas de moluscos a escala regional. En términos espaciales, los resultados refuerzan el patrón definido para el Holoceno tardío en la región, que indica una dispersión más acotada para los restos de volutas respecto de las cuentas y otras clases de moluscos. Se aporta nueva información para la caracterización tecnomorfológica de artefactos elaborados sobre conchas de Volutidae y se reporta el hallazgo más austral registrado hasta el momento para cuentas elaboradas sobre el gasterópodo terrestre Megalobulimus sp.

Abstract Twenty-one shell elements from different archaeological contexts in the interior of Santa Cruz province are analyzed in this paper, considerably increasing the existing sample for Southern Patagonia. Their characteristics and distribution are discussed in relation to the information available regarding the forms of exploitation and circulation of mollusk shells on a regional scale. In spatial terms, the results reinforce the pattern defined for the Late Holocene in the region which indicates a more limited dispersion for the remains of volutes with respect to beads and other mollusk classes. New information is provided for the technomorphological characterization of artifacts made from Volutidae shells, and the southernmost finding recorded to date for beads made from the terrestrial gastropod Megalobulimus sp. is reported.

Resumo Achatina fulica é um molusco terrestre conhecido como caramujo gigante africano que está relacionado a problemas ambientais, econômicos, urbanos e de saúde pública. Como medidas de controle para esse molusco, são utilizados sal de cozinha (NaCl) e óxido de cálcio (CaO), e as iscas são compostas de metaldeído. No entanto, essas medidas têm toxicidade ambiental e impactam o solo. Desta forma, produtos naturais foram testados neste molusco para descobrir e desenvolver uma substância para combater esta praga urbana e agrícola. Este artigo tem como objetivo avaliar estudos envolvendo produtos naturais para controle da população de Achatina fulica. Artigos e trabalhos publicados em livros foram incluídos no presente trabalho. Um total de 1.103 trabalhos foram encontrados durante a pesquisa. Destes, 14 trabalhos atendiam ao objetivo desta revisão e foram incluídos neste artigo. Os testes não possuem padronização metodológica, não possuem concentração máxima para serem considerados ativos ou tempo máximo de exposição. Observou-se uma falta de padronização na metodologia de testes em A. fulica. A realização de testes em outras fases da vida do molusco, bem como testes que analisem outros parâmetros, são essenciais. Apenas um artigo analisado apresentou análise fitoquímica. Também não foram relatados testes de ecotoxicidade. Alguns extratos apresentaram resultados promissores, com destaque para o extrato aquoso de Capsicum frutescens. Mais estudos investigando a atividade molusquicida de produtos naturais sobre A. fulica são necessários. É muito relevante que os novos estudos apresentem uma análise fitoquímica dos extratos testados, bem como estudos de ecotoxicidade.

Abstract Achatina fulica is a terrestrial mollusk known as the giant African snail that is related to environmental, economic, urban, and public health problems. As control measures for this mollusk, cooking salt (NaCl) and calcium oxide (CaO) are used, and baits are composed of metaldehyde. However, these measures have environmental toxicity and impact the soil. In this way, natural products have been tested on this mollusk to discover and develop a substance to combat this urban and agricultural pest. This article aims to evaluate studies involving natural products to control the population of Achatina fulica. Articles and works published in books were included in the present work. A total of 1,103 works were found during the search. Of these, 14 works met the objective of these review and were included in this article. The tests do not possess methodological standardization, do not have a maximum concentration to be considered active, or a maximum exposure time. A lack of standardization in the methodology of tests on A. fulica was observed. The performance of tests on other life stages of the mollusk, as well as tests that analyze other parameters, are essential. Only one article analyzed presented phytochemical analysis. No ecotoxicity tests were reported either. Some extracts showed promising results, highlighting the aqueous extract of Capsicum frutescens. More studies investigating the molluscicidal activity of natural products on A. fulica are needed. It is very relevant that the new studies present a phytochemical analysis of the tested extracts, as well as ecotoxicity studies.

Abstract In this study, we aimed to evaluate the synergistic effect between the Amazon seasonality and the El Niño climate anomaly (2015/16 event) on the growth of oysters cultivated on the Amazon coast in comparison with the growth of oysters in a normal year (2013). It should be noted that both experiments determined the absolute growth of oysters Crassostrea gasar by reading microgrowth using an internal calcein marker. the results clearly indicate the synergistic effect of the Amazon seasonality with the El Niño climatic anomaly. thus, in normal years, the best oyster growth performance occurs in the dry season, while in El Niño years it occurs in the wet season. This is the first study carried out in the Amazon region that aims to analyze the effects of El Niño on the production of fishery resources from aquaculture. Such information enables adaptations in the planning of the production cycle of oyster farming, serving as an investment indicator. 2015/16 201516 2015 16 (2015/1 event 2013. 2013 . (2013) marker thus season aquaculture farming indicator 2015/1 20151 201 1 (2015/ (2013 2015/ 20 (2015 (201 2 (20 (2 (

Resumo: Objetivo O objetivo foi avaliar a diversidade beta de macroinvertebrados associados a macrófitas aquáticas em uma planície de inundação de um rio regulado por hidrelétrica. Testamos duas hipóteses: (1) macroinvertebrados associados a macrófitas aquáticas têm maior diversidade beta (em ambos os componentes turnover e nestedness) em áreas a jusante próximas ao Rio São Francisco se comparadas a áreas a montante, e (2) lagos próximos são mais similares, independente de sua posição em relação à barragem. Métodos Foram amostrados quatro lagos, sendo dois a montante (L1- natural e L2- regulado pela Pequena Central Hidrelétrica - PCH) e dois a jusante (L3, L4- não regulados pela PCH). Resultados Nossa primeira hipótese foi corroborada porque encontramos maior turnover no lago próximo ao Rio São Francisco (L4 a jusante), onde ocorre maior riqueza de espécies não nativas de moluscos, enquanto aninhamento foi mais importante nos lagos a montante e a jusante da PCH (L1, L2, L3). Nossa segunda hipótese também foi corroborada porque lagos mais próximos são mais similares do que lagos distantes. Finalmente, essas diferenças foram consistentes entre lagos para as macrófitas emergentes, com folhas flutuantes e submersas. Conclusões As macrófitas aquáticas são importantes habitats para macroinvertebrados na bacia do Rio Pandeiros, com maior diversidade beta no lago mais próximo ao Rio São Francisco. Resumo hidrelétrica hipóteses 1 (1 nestedness 2 (2 barragem L1 L (L1 L2 L3, L3 (L3 L4 PCH. . (L jusante, , jusante) moluscos L1, L3. L3) distantes Finalmente emergentes submersas Pandeiros (

Abstract: Aims We assessed the beta diversity of macroinvertebrates associated with aquatic macrophytes in a dam-regulated river floodplain. We tested two hypotheses: (1) macroinvertebrates associated with aquatic macrophytes have higher beta diversity (higher turnover and nestedness components) in the downstream areas closer to the São Francisco River compared to upstream sites; (2) closer lakes share a higher similarity of aquatic macroinvertebrates, disregarding their position relative to the dam. Methods We sampled four lakes, including two upstream (L1- natural and L2- regulated by a Small Hydropower Dam - SHD) and two downstream (L3, L4, unregulated) by the SHD. Results We corroborated our first hypothesis because we found a higher turnover of macroinvertebrates associated with aquatic macrophytes close to the São Francisco River (L4 downstream), where higher non-native mollusk species richness occurs, while we found higher nestedness upstream and downstream of the SHD (L1, L2, L3). We corroborated our second hypothesis, as closer lakes are more similar than distant lakes. Finally, these differences were consistent between lakes for emergent, floating leaf, and submerged aquatic macrophytes. Conclusions Aquatic macrophytes are essential habitats for macroinvertebrates in the Pandeiros River basin, with higher beta diversity in the lake closer to the São Francisco River. Abstract damregulated dam floodplain hypotheses 1 (1 components sites 2 (2 L1 L (L1 L2 L3, L3 (L3 L4 unregulated (L downstream, , downstream) nonnative non native occurs L1, L3. . L3) Finally emergent leaf basin (

Resumo: Objetivo Inventariar os danos causados aos ambientes naturais ou à biodiversidade nativa por por espécies exóticas é desafiador. Nós testamos se o número de detecções de espécies exóticas é afetado pelo número total de espécies exóticas ou pela riqueza de exóticas invasoras, com o intuito de predizer que grupos de espécies são mais prováveis futuros invasores. Métodos Nós apresentamos informações obtidas de um senso nacional conduzido sobre organismos exóticos anelídeos, anfíbios, cnidários, crustáceos, macrófitas aquáticas, microrganismos, moluscos, nematelmintos, peixes, platelmintos e répteis para todas as bacias hidrográficas do país. Utilizamos o número de detecções como variável dependente da riqueza de espécies exóticas, por grupo taxonômico e da riqueza de espécies exóticas invasoras. Resultados Nós obtivemos 1.896 detecções de diferentes 183 espécies aquáticas. Peixes e moluscos foram os invasores comuns já que suas detecções são mais frequentes do que o esperado ao acaso, considerando todas as espécies ocorrendo nos ecossistemas de água doce do país. Nós também encontramos relações positivas e robustas entre as detecções por grupo taxonômico e a riqueza em espécies por grupo. Conclusões Os resultados ilustram como o ambiente de água doce brasileiro é frágil a invasões biológicas e destacam a necessidade de ações efetivas direcionadas à questão. A incerteza científica a respeito do status de espécies exóticas e seu podencial invasor é grande, o que leva à necessidade de precaução a respeito destas espécies. Apesar do cenário atual, novas políticas abrem opotunidades para que parques aquáticos com organismos exóticos se dispersem mais no Brasil o que deve aumentar ainda mais a pressão sobre ecossistemas naturais e espécies nativas, reforçando a necessidade já manifestada pela comunidade científica, de maior atenção ao tema. Resumo desafiador invasoras anelídeos anfíbios cnidários crustáceos aquáticas microrganismos nematelmintos peixes país 1896 1 896 1.89 18 acaso questão grande atual nativas tema 189 89 1.8 8 1.

Abstract: Aim Assessing the damage caused to natural environments and native biodiversity by alien species is challenging. We tested whether the number of detections of alien species is affected by total alien or total invader alien species richness, considering the importance of predicting which species are more probable future invaders. Methods We summarized a research information survey conducted on alien amphibians, annelids, aquatic macrophytes, cnidarians, crustaceans, fish, microorganisms, mollusks, nemathelminths, platyhelminths, and reptiles, and for Brazilian watersheds. We used linear regressions between detections and total alien species richness and between detections and invader species richness. Results We obtained 1,896 alien detections of 183 aquatic species in Brazil. Fish and mollusk species were the commonest invaders due to their detections being more frequent than expected by chance, considering all the alien species occurring in Brazilian freshwater ecosystems. We also found positive and robust linear relationships between alien species detections and alien species richness. Conclusions Our results illustrate how Brazilian freshwater systems are fragile to alien invasions and highlight the need for effective action to address this question. Scientific uncertainty in Brazil regarding the status of some alien species and their potential harm is high, highlighting the need for a cautionary overview of invaders. Despite this scenario, new policies create opportunities for aquatic parks with exotic organisms to spread further in Brazil, which, in actual Brazilian conditions, is likely to increase the pressure on natural ecosystems and native species. This reinforces the already expressed need by the scientific community for greater attention to the issue. Abstract challenging amphibians annelids macrophytes cnidarians crustaceans fish microorganisms mollusks nemathelminths platyhelminths reptiles watersheds 1896 1 896 1,89 18 chance question high scenario conditions issue 189 89 1,8 8 1,

Resumo: Um dos impactos ambientais mais comuns que tem causado efeitos irreversíveis nos ecossistemas é a introdução de espécies exóticas. Além dos desastres ecológicos que podem ser provocados, como o declínio e a extinção de espécies nativas, este fenómeno pode gerar perdas económicas significativas e a possibilidade de propagação de parasitas que são transmitidos por estas espécies exóticas. Esses processos podem ser acentuados pelas mudanças climáticas, que ao longo do tempo alteram o padrão de distribuição global das espécies afetadas, gerando casos de sobreposição de nicho com espécies que compartilham nichos semelhantes. Nesse sentido, o conhecimento sobre as áreas com possível ocorrência dessas espécies pode direcionar as medidas de monitoramento e controle. Neste estudo, desenvolvemos modelos de previsão atuais e futuros para identificar áreas de adequabilidade na região Neotropical para Melanoides tuberculata (Müller, 1774) e nove espécies de moluscos nativos do continente americano, utilizando a ferramenta de modelagem de nicho ecológico. Além disso, avaliamos a sobreposição de nicho ecológico entre a espécie invasora e as espécies nativas de moluscos de água doce para verificar se os efeitos das mudanças climáticas alterariam a distribuição desses organismos. Para a elaboração dos modelos de predição, foram adotados os seguintes procedimentos metodológicos: registros de ocorrência dos moluscos em diferentes bases de dados e busca de dados ambientais para condições climáticas em cenários atuais e futuros no WorldClim 2.0 (SSP2-4.5 e SSP2-8.5). Além disso, foram realizados procedimentos de modelagem utilizando sete pacotes do software R, avaliação dos modelos utilizando a métrica True Skill Statistic (TSS), construção de mapas e quantificação e sobreposição de nicho ecológico das espécies incluídas na análise. Os resultados indicaram que várias áreas da região Neotropical são adequadas para a ocorrência de M. tuberculata nos cenários atuais. Além disso, as áreas adequadas para a sua ocorrência serão provavelmente alargadas em ambos os cenários futuros. Para as espécies nativas, houve diferenças significativas em relação às áreas de aptidão, com uma redução para algumas espécies. Testes de similaridade de nicho indicaram sobreposição significativa apenas entre M. tuberculata e o planorbídeo Biomphalaria straminea (Dunker, 1848). Verificamos que a expansão de M. tuberculata pode ter consequências negativas, incluindo a redução de espécies nativas de gastrópodes e a disseminação de trematódeos de importância médica e veterinária que este molusco pode transmitir. Resumo exóticas provocados afetadas semelhantes sentido controle estudo Müller, Müller (Müller 1774 americano disso organismos predição metodológicos 20 2 0 2. SSP24.5 SSP245 SSP SSP2 4.5 4 5 (SSP2-4. SSP28.5. SSP285 8.5 . 8 SSP2-8.5) R TSS, TSS , (TSS) análise M aptidão Dunker, Dunker (Dunker 1848. 1848 1848) negativas transmitir 177 SSP24 SSP24. 45 4. (SSP2-4 SSP28 SSP28.5 85 8. SSP2-8.5 (TSS 184 17 (SSP2- SSP28. SSP2-8. 18 1 (SSP2 SSP2-8 (SSP SSP2-

Abstract: One of the most common environmental impacts that has caused irreversible effects on ecosystems is the introduction of exotic species. In addition to the ecological disasters that can be caused, such as the decline and extinction of native species, this phenomenon can generate significant economic losses and the possibility of the spread of parasites that are transmitted by these exotic species. These processes can be accentuated by climate change, which over time alters the global distribution pattern of the affected species, generating cases of niche overlap with species that share similar niches. In this sense, the knowledge about the areas with possible occurrence these species can direct the monitoring and control measures. In this study, we developed current and future prediction models to identify areas of suitability in the Neotropics for Melanoides tuberculata (Müller, 1774) and nine species of mollusks native to the American continent using the ecological niche modeling tool. In addition, we evaluated the ecological niche overlap between the invasive species and the native species of freshwater mollusks to verify whether the effects of climate change would alter the distribution of these organisms. The following methodological procedures were adopted to prepare the forecasting models: records of occurrence of the mollusks in different databases and search of environmental data for climate conditions in current and future scenarios in WorldClim 2.0 (SSP2-4.5 and SSP2-8.5). Besides, modeling procedures using seven packages of R software, evaluation of the models using the true skill statistic (TSS) metric, construction of maps and quantification and overlapping of ecological niche of the species included in the analysis. The results indicated that several areas of the Neotropics are suitable for the occurrence of M. tuberculata in the current scenarios. Moreover, the suitable areas for its occurrence will probably be expanded in both future scenarios. For native species, there were significant differences in relation to the areas of suitability, with a reduction for some species. Niche similarity tests indicated significant overlap only between M. tuberculata and the planorbid Biomphalaria straminea (Dunker, 1848). We discuss that the expansion of M. tuberculata can have negative consequences, including the reduction of native gastropod species and the spread of trematodes of medical and veterinary importance that this mollusk can transmit. Abstract niches sense measures study Müller, Müller (Müller 1774 tool organisms 20 2 0 2. SSP24.5 SSP245 SSP SSP2 4.5 4 5 (SSP2-4. SSP28.5. SSP285 8.5 . 8 SSP2-8.5) Besides software TSS (TSS metric analysis M Moreover Dunker, Dunker (Dunker 1848. 1848 1848) consequences transmit 177 SSP24 SSP24. 45 4. (SSP2-4 SSP28 SSP28.5 85 8. SSP2-8.5 184 17 (SSP2- SSP28. SSP2-8. 18 1 (SSP2 SSP2-8 (SSP SSP2-

Abstract. Mercury (Hg) is mainly incorporated into humans through the consumption of contaminated foods. Mercury was measured and the methyl-Hg (MeHg) concentration was estimated in canned mollusks sold in northwestern Mexico to assess the health risk to consumers. Five mollusk types were considered: oysters, clams, octopuses, mussels, and squids. The Hg concentration of mussels was significantly (P < 0.05) lower than those of the other bivalves (oysters and clams) and cephalopods (squids and octopuses). The average Hg concentration in bivalves (0.013 mg·kg-1) was significantly (P < 0.05) lower than that of cephalopods (0.018 mg·kg-1). The estimated MeHg concentrations were also lower in bivalves than in cephalopods. Based on our results, no health risk is associated with the consumption of canned mollusks that are sold in northwestern Mexico. The Hg and MeHg concentrations followed the order of octopuses > squids = clams > oysters > mussels. The Hg and MeHg concentrations in the mollusks evaluated in this study were below the maximum permissible limits for human consumption in Mexico.

Resumen. El mercurio (Hg) se incorpora principalmente en los seres humanos a través del consumo de alimentos contaminados. Se midió el Hg y se estimó el metilmercurio (MeHg) en moluscos enlatados que se venden en el noroeste de México para evaluar el riesgo para la salud de los consumidores. Se consideraron 5 tipos de moluscos: ostiones, almejas, pulpos, mejillones y calamares. La concentración de Hg en los mejillones fue significativamente (P < 0.05) más baja que la de los otros bivalvos (ostras y almejas) y cefalópodos (calamares y pulpos). La concentración promedio de Hg en los bivalvos (0.013 mg·kg-1) fue significativamente (P < 0.05) menor que la de los cefalópodos (0.018 mg·kg-1). Las concentraciones estimadas de MeHg también fueron menores en los bivalvos que en los cefalópodos. De acuerdo con nuestros resultados, no existe riesgo relacionado con el consumo de moluscos enlatados en el noroeste de México. La secuencia de las concentraciones de Hg fue pulpos > calamares = almejas > ostiones > mejillones. Las concentraciones de Hg y MeHg en los moluscos evaluados en este estudio estaban por debajo de los límites máximos permitidos para el consumo humano en México.

Abstract. Marine mollusks provide important ecosystem services. They create habitats for benthic organisms, filter water, biodeposit organic carbon in the seafloor, and serve as food sources for other organisms. Studies of mollusk diversity require time-consuming methods to process samples and identify species. Thus, it is not surprising that most studies have focused on macromollusks that can be collected and processed easily, ignoring micromollusk species. Without understanding the ecology and distributions of micromollusks properly, it is impossible to assess their populations and implement adequate conservation measures. Here we present microgastropods collected in Bahia de los Angeles at the family level for September 2013 (summer) and February 2014 (winter). During each season, we sampled 6 coastal sediment stations, and analyzed depth, salinity, temperature, granulometry, and organic matter. A total of 20,353 specimens were collected: 15,310 in summer and 5,043 in winter. Seven micromollusk families were identified: Barleeidae, Caecidae, Cerithiidae, Eulimidae, Pyramidellidae, Rissoidae, and Tornidae. Caecidae and Barleeidae exhibited the highest densities among all families in summer and winter, respectively (278,044 ind·m-2, 142,222 ind·m-2). The lowest densities for summer and winter were observed for the Tornidae family (~1,867 ind·m-2, ~1,411 ind·m-2). Barleeidae, Caecidae, Cerithiidae, Rissoidae, and Tornidae were classified as herbivorous and detritivorous; Eulimidae and Pyramidellidae, as carnivorous and ectoparasitic. Tornidae and Eulimidae showed symbiotic relationships with various invertebrate species. The Bayesian analysis of variance indicated a high probability of differences only in summer (BF > 3). When comparing the stations in both periods, all stations, except station 6, showed differences between periods (BF > 3). The canonical correlation analysis indicated some associations between family abundances and temperature. This study provides valuable information that expands the knowledge of micromollusk biodiversity in the coastal area of Bahia de los Angeles, an important site for conservation in Mexico.

Resumen. Los moluscos marinos brindan importantes servicios ecosistémicos debido a que generan hábitats para organismos bentónicos, filtran agua, biodepositan carbono orgánico en el fondo marino y sirven como fuente de alimento para otros organismos. Los estudios de diversidad de moluscos requieren métodos de muestreo e identificación de especies muy tardados. Por lo tanto, no sorprende que la mayoría de los estudios se centren en los macromoluscos, los cuales son fácilmente recolectados y procesados, ignorando las especies de micromoluscos cuya identificación es difícil y tardada. Si no se comprende la ecología y distribución de los micromoluscos, es imposible evaluar sus poblaciones e implementar medidas de conservación. Aquí presentamos microgasterópodos recolectados en Bahía de los Ángeles a nivel de familia en 2 muestreos, en septiembre de 2013 (verano) y en febrero de 2014 (invierno). En cada temporada, muestreamos 6 estaciones costeras y realizamos mediciones de profundidad, salinidad, temperatura, granulometría y contenido de materia orgánica. Se recolectaron 20,353 ejemplares: 15,310 en verano y 5,043 en invierno. Se identificaron 7 familias: Barleeidae, Caecidae, Cerithiidae, Eulimidae, Pyramidellidae, Rissoidae y Tornidae. Caecidae y Barleeidae presentaron la máxima densidad en verano e invierno, respectivamente (278,044 ind·m-2, 142,222 ind·m-2). Tornidae presentó las densidades más bajas para verano e invierno (~1,867 ind·m-2, ~1,411 ind·m-2). Barleeidae, Caecidae, Cerithiidae, Rissoidae y Tornidae se clasificaron como herbívoros y detritívoros; Eulimidae y Pyramidellidae, como carnívoros y ectoparásitos. Tornidae y Eulimidae muestran relaciones simbióticas con varias especies de invertebrados. El análisis bayesiano indicó una alta probabilidad de diferencias para verano (BF > 3). Al comparar la misma estación entre muestreos, solo la estación 6 mostró diferencias entre periodos (BF > 3). Este estudio brinda información valiosa que amplía el conocimiento de la biodiversidad de micromoluscos en la zona costera de Bahía de los Ángeles, un importante sitio de conservación en México.

Abstract: Oyster Crassostrea spp. is the bivalve mollusk with the largest commercial volume in Cuba. Populations should be assessed for their management and conservation, which has been performed but with different methodologies and only in certain localities, making it difficult to evaluate and compare between periods and regions. Therefore, current state of the resource was to be determined according to maximum sustainable yield (MSY), biomass for the maximum sustainable yield (BMSY), and corresponding fishing mortality rate (FMSY). Catch Maximum Sustainable Yield (CMSY) model was applied with Monte Carlo method, resource biomass and exploitation were evaluated for northwestern (NW), northeastern (NE), southeastern (SE), and southwestern (SW) regions of the insular platform, as well as for periods (1960-1991 and 1992-2020). From 1992-2020, a 50% reduction in oyster landings was recorded when compared with 1960-1991 period, which was reflected in population indicators according to estimated fishery reference points. Based on applied model and method, current oyster fishery management is perceived as unsustainable with stock depletion and overfishing in NW, NE, and SW regions. Cuban SE region shows a more favorable status. Oyster farming should increase to obtain higher production and broodstock biomass to decrease fishing effort on wild populations.

Resumen: En Cuba, la ostra Crassostrea spp. es el molusco bivalvo de mayor volumen comercial. La evaluación de sus poblaciones es necesaria para su manejo y conservación, pero se ha realizado con diferentes metodologías y solo en localidades puntuales, lo que dificulta su evaluación y comparación entre periodos y regiones. Por lo tanto, se determinó el estado actual del recurso según el rendimiento máximo sostenible (MSY), biomasa para el rendimiento máximo sostenible (BMSY) y la tasa de mortalidad por la pesca (FMSY) correspondiente. Se aplicó el modelo CMSY con método de Monte Carlo, y se evaluó la biomasa y la explotación del recurso para las regiones noroeste (NW), noreste (NE), sureste (SE) y suroeste (SW) de la plataforma insular, así como por periodos (1960-1991 y 1992-2020). Durante 1992-2020 se registró una reducción del 50% en los desembarques de ostras respecto al periodo 1960-1991, lo que se reflejó en los indicadores poblacionales según los puntos de referencia evaluados. De acuerdo con el modelo y método aplicados, la gestión pesquera actual de la ostra se percibe no-sostenible, con agotamiento del stock y sobrepesca en las regiones NW, NE y SW. La región SE del país presenta un estado más favorable. Se sugiere incrementar la ostricultura para obtener mayor producción y biomasa de reproductores para disminuir el esfuerzo de pesca sobre las poblaciones silvestres.

Resumen El carbonato de calcio está presente en muchas estructuras biológicas, como la concha de bivalvo, que se compone principalmente de dos polimorfos de CaCO3: calcita y aragonito. Sin embargo, existen otras formas de carbonato de calcio como vaterita y carbonato de calcio amorfo (ACC) que no se reportan comúnmente. La selección de polimorfos está influenciada por la concentración de sal, los iones cofactores y la presencia de proteínas de la matriz de la cubierta (SMP) que regulan la deposición de carbonato de calcio, entre otros factores. En este estudio, se evaluó la cristalización in vitro de carbonato de calcio de cuatro soluciones salinas diferentes (1: 40 mM CaCl2, MgCl2, 100 mM NaHCO3; 2: CaCl2, 100 mM Na2CO3; 3: 40 mM CaCl2, MgSO4, 100 mM Na2CO3; 4: CaCl2/MgCl2, 100 mM NaHCO3) en dos molaridades (40 o 100 mM)con diferentes concentraciones la proteína Ps19 (0.2, 0.7 y 1.2 µg/µL) una proteína insoluble extraída de la concha de Pteria sterna, descrita anteriormente como promotora de la cristalización de plaquetas de aragonita. Las cristalizaciones in vitro mostraron que Ps19 es capaz de inducir la deposición de aragonita y calcita de forma dependiente de la dosis, pero también de vaterita en determinadas condiciones, actuando como promotor e inhibidor de la cristalización. Los resultados contribuyen a comprender cómo Ps19 controla la precipitación de polimorfos de calcio en el crecimiento de la capa prismática y de nácar de la concha de P. sterna.

Abstract Calcium carbonate is present in many biological structures such as bivalve shells, which is composed mainly of two CaCO3 polymorphs: calcite and aragonite. However, other forms of calcium carbonate exist like vaterite and amorphous calcium carbonate (ACC) that are not commonly reported. Polymorph selection is influenced by salt concentration, cofactor ions, and the presence of shell matrix proteins (SMPs) which regulates calcium carbonate deposition, among other factors. In this study, in vitro calcium carbonate crystallization of four different saline solutions (1: 40 mM CaCl2, MgCl2, 100 mM NaHCO3; 2: CaCl2, 100 mM Na2CO3; 3: 40 mM CaCl2, MgSO4, 100 mM Na2CO3; 4: CaCl2/MgCl2, 100 mM NaHCO3) at two molarities (40 o 100 mM) was evaluated with increased concentrations of the Ps19 protein (0.2, 0.7 y 1.2 µg/µL), an insoluble extracted protein from the Pteria sterna shell, previously described as a promotor of aragonite platelet crystallization. In vitro crystallizations showed that Ps19 is capable to induce aragonite and calcite deposition in a dose-dependent manner, but also vaterite under certain conditions, acting as a promoter and inhibitor of crystallization. The results contribute to understand how Ps19 control precipitation of calcium polymorphs in the growth of the prismatic and nacre layer of the shell of P. sterna.

ABSTRACT The snail Trochita trochiformis is a mollusk captured on the coasts of Jalisco and Guerrero of the Mexican Pacific. Despite its importance in artisanal fisheries, information on its population parameters is still being determined. This research aimed to determine the diameter-weight relationship, sex ratio, cohorts, and growth of this species. Specimens were captured from October 2019 to September 2021. Shell diameter (Sd), total weight (TW), and the sex of the organisms were gathered from a total of 1763 females and 956 males. The sex ratio was 1.84:1, and the X2 test (P < 0.05) indicated significant differences. The Sd-Tw relationship for females and males was potential-type. The values of the allometry coefficient for both sexes were b = 2.61, b = 2.60 for females, and b = 2.62 for males. In all three cases, the t-Student test indicated negative allometric growth, which indicates that the species first grows in shell diameter, then in body weight. The ANCOVA did not show significant differences in the Sd-Tw relationships between sexes (P = 0.902). The Kolmogorov-Smirnov test applied to the Sd data showed differences between sexes (P < 0.001). In females, differences were observed in 71.5% by monthly comparisons, while in males, differences were found in 58.1%. Multinomial analysis showed three modal groups and 14 individual cohorts for both females and males. Case 2 of the Schnute model was the best for females (wi = 0.39) and males (wi = 0.53), showing sigmoidal Gompertz-type growth. The resulting growth curves showed that females exhibit accelerated growth concerning males and that both sexes reach their maximum size, 88.04 and 86.23 mm, respectively, at approximately 10 years of age.

ABSTRACT Iphigenia brasiliensis is a bivalve mollusk exploited as a shellfish and subsistence resource on the Brazilian coast, mainly in the north and northeast regions. Genetic (allozyme electrophoresis revealed eight gene loci) and morphological variations (multivariate morphometry of valves used 13 linear measurements of traditional and 19 Fourier coefficients of geometric morphometry) were studied, considering the geographic (445 km of the southwest tropical Atlantic), environmental (mangroves and channels of communication with the sea of three estuaries in the state of Rio de Janeiro), and temporal dimensions (over two years). I. brasiliensis showed high levels of genetic variation (the average number of alleles per locus ranged from 2.8 to 3.4, and the average heterozygosity ranged from 0.441 to 0.675). Bayesian analysis of population partitioning showed that the highest LnP(D) value was achieved for K = 3. These results indicated mixed ancestry, possibly oscillations in the dispersion dynamics among the different sampling groups, and temporal oscillations in the population sizes due to the anthropogenic influence on the studied estuaries. The results of morphological variation, inferred by the PERMANOVA from the Fourier analysis, indicated that a similar influence might occur in valves (also, the discriminant analysis showed that different groups could be consistently identified). In this sense, the studied populations may be organized in a dynamic of metapopulations. Finally, these are the first data on morphological and genetic variation of the species in the latitudinal, environmental, and temporal dimensions studied simultaneously, thus providing relevant information for the exploration, management, and conservation of this commercially important species.

Abstract Disarticulated shells of three bivalve mollusk species (Anomalocardia brasiliana, Codakia orbicularis, and Divaricella quadrisulcata) were experimentally tested in laboratory flumes to determine the threshold of motion and final orientation of the valves. A total of 150 current flow experiments were conducted on single shells resting on a fixed sand bed. This study demonstrated that shells in the convex-up position are more resistant to flow when the umbo is pointing downstream rather than upstream. Moreover, species with higher frontal areas were more likely to be entrained at lower flow velocities. Results of dimensionless shear stress exhibited values far below the threshold of grains movement for beds of uniform roughness (Shields curve). It was observed that circular shells in convex-up positions were mostly orientated with the umbo pointing downstream. Conversely, elliptical shells in convex-up position tended to align their longer axis parallel to the flow with the posterior side of the valve pointing downstream. These results are not only directly applicable in interpretations of incipient shell motions and in paleocurrent analyses from field and sample data, but also support construction of accurate geological models. Anomalocardia brasiliana orbicularis quadrisulcata valves 15 bed convexup convex up upstream Moreover velocities Shields curve. curve . curve) Conversely data models 1

Abstract Many studies about fasciolosis control have been carried out, whether acting on the adult parasite or in Pseudosuccinea columella, compromising the development of the larval stages. The present study aimed to evaluate, under laboratory conditions, the susceptibility of P. columella to Heterorhabditis bacteriophora HP88, during for 24 and 48 hours of exposure. The snails were evaluated for 21 days for accumulated mortality; number of eggs laid; hatchability rate; biochemical changes; and histopathological analysis. We found that exposure induced a reduction in glucose and glycogen levels, characterizing a negative energy balance, due to the depletion of energy reserves as a result of the direct competition established by the nematode/endosymbiont bacteria complex in such substrates. A mortality rate of 48.25% and 65.52% was observed in the group exposed for 24 h and 48 h, respectively, along with significant impairment of reproductive biology in both exposed groups in relation to the respective controls. The results presented here show that P. columella is susceptible to the nematode H. bacteriophora, with the potential to be used as an alternative bioagent in the control of this mollusk, especially in areas considered endemic for fascioliasis, in line with the position expressed by the World Health Organization Health. out stages evaluate conditions P HP88 HP 2 4 laid changes analysis levels balance nematodeendosymbiont endosymbiont substrates 4825 25 48.25 6552 65 52 65.52 respectively controls H mollusk fascioliasis HP8 482 48.2 655 6 5 65.5 48. 65.

Resumo Muitos estudos têm sido realizados sobre o controle da fasciolose, seja atuando no parasito adulto, seja em Pseudosuccinea columella, comprometendo o desenvolvimento das fases larvais. O presente estudo teve como objetivo avaliar, em condições laboratoriais, a suscetibilidade de P. columela à Heterorhabditis bacteriophora HP88, durante 24 e 48 horas de exposição. Os moluscos foram avaliados por 21 dias para mortalidade acumulada; número de ovos postos; taxa de eclodibilidade; alterações bioquímicas; e análise histopatológica. Constatou-se que a exposição induziu a redução nos níveis de glicose e glicogênio, caracterizando um balanço energético negativo, devido ao esgotamento das reservas energéticas, decorrentes da competição direta estabelecida pelo complexo nematoide/bactéria endossimbionte nesses substratos. Foi observada uma taxa de mortalidade de 48,25% e65,52% no grupo exposto por 24 h 48 h, respectivamente, juntamente com comprometimento significativo da biologia reprodutiva em ambos os grupos expostos em relação aos respectivos controles. Os resultados aqui apresentados, mostram que P. columela é suscetível ao nematódeo H. bacteriophora, com potencial para ser utilizada como um bioagente alternativo no controle dess molusco, especialmente em áreas consideradas endêmicas para fasciolose, em linha com a posição expressa pela Organização Mundial da Saúde. fasciolose adulto columella larvais avaliar laboratoriais P HP88 HP 2 4 acumulada postos eclodibilidade bioquímicas histopatológica Constatouse Constatou se glicogênio negativo energéticas nematoidebactéria nematoide bactéria substratos 4825 25 48,25 e6552 e65 52 e65,52 respectivamente controles apresentados H molusco Saúde HP8 482 48,2 e655 e6 5 e65,5 48, e65,