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We employed a meta-analysis to determine if the presumed resilience of decapods to ocean acidification extends to all biological aspects, environments, and life stages. Most response categories appeared unaffected by acidification. However, certain fitness-related traits (growth, survival, and, to some extent, calcification) were impacted. Acid-base balance and stress response scaled positively with reductions in pH, which maintains homeostasis, possibly at the cost of other processes. Juveniles were the only stage impacted by acidification, which is believed to reduce recruitment. We observed few differences in responses to acidification among decapods inhabiting contrasting environments. Our meta-analysis shows decapods as a group slightly to moderately sensitive to low pH, with impacts on some biological aspects rather than on all specific life stages or habitats. Although extreme pH scenarios may not occur in the open ocean, coastal and estuarine areas might experience lower pH levels in the near to medium future, posing potential challenges for decapods.

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Introduction: Echinoids (sea urchins) provide shelter for a variety of facultative or obligatory ectosymbionts. Objective: To evaluate the hypothesis that decapods and fishes prefer to associate with echinoid individuals and species that have longer spines. Methods: We visually studied the frequency of decapod crustaceans and fishes associated with echinoids in shallow water (< 4 m) and deeper water (5-20 m) at Los Cabos, Baja California Sur, Mexico, during 1-6 January 2019. Results: We inspected 1 058 echinoids of six species. Five decapod species associated with three species of echinoids. When compared with other echinoid species, in shallow water, decapods associated 5.1 times more often with the longest-spined echinoid Diadema mexicanum (7.0 times more decapods per individual D. mexicanum); in deeper water, association frequency was similar for all echinoid species. Fourteen fish species associated with four echinoid species. In shallow water, fishes associated 2.6 times more with D. mexicanum (4.5 times more fishes per individual). There was no preferred echinoid species in deeper water. Longer-spined D. mexicanum had more decapods and fishes. Associations were more frequent in shallow water. Multiple individuals and species of decapods and fish often associated together with a single D. mexicanum. The decapod that presumably is Tuleariocaris holthuisi showed a possible obligatory association with one of the equinoids (D. mexicanum); the other decapods and all fish species are facultative associates. Conclusion: Our results support the hypothesis that decapods and fishes associate most frequently with echinoids with the longest spines, presumably to reduce the risk of predation.

Introducción: Los equinoideos (erizos de mar) brindan refugio a una variedad de ectosimbiontes facultativos u obligatorios. Objetivo: Evaluar la hipótesis de que los decápodos y los peces prefieren asociarse con individuos y especies de equinoideos con espinas más largas. Métodos: Estudiamos visualmente la frecuencia de crustáceos decápodos y peces asociados con equinoideos en aguas poco profundas (< 4 m) y aguas más profundas (5-20 m) en Los Cabos, Baja California Sur, México, del 1-6 de enero 2019. Resultados: Examinamos 1 058 equinoideos de seis especies. Cinco especies de decápodos se asociaron con tres especies de equinoideos. Al comparar con otras especies de equinoideos, en aguas poco profundas, los decápodos se asociaron 5.1 veces más frecuentemente con la especie de equinoideo de espinas más largas, Diadema mexicanum (7.0 veces más decápodos por individuo en D. mexicanum); en aguas más profundas, la frecuencia fue similar para todas las especies de equinoideos. Catorce especies de peces se asociaron con 4 especies de equinoideos. En aguas poco profundas, los peces se asociaron 2.6 veces más con D. mexicanum (4.5 veces más peces por individuo). No hubo preferencia por una especie de equinoideo en aguas más profundas. Individuos de D. mexicanum con espinas largas tuvieron más asociación con decápodos y peces. Las asociaciones se dieron con mayor frecuencia en aguas poco profundas. Múltiples individuos y especies de decápodos y peces a menudo se asociaron con un solo D. mexicanum. Un decápodo que presumiblemente es Tuleariocaris holthuisi mostró una posible asociación obligatoria con uno de los equinoideos (D. mexicanum); las otras especies de decápodos y todas las especies de peces presentaron asociaciones facultativas. Conclusión: Nuestros resultados apoyan la hipótesis de que los decápodos y los peces se asociaron con mayor frecuencia con los equinoideos con las espinas más largas, presumiblemente para reducir el riesgo de depredación.

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In order to understand the role of lower order tributaries in the population structuring of the freshwater anomuran crab Aegla parana Schmitt, 1942, a study on the distribution of demographic categories was carried out along Negro River and in its tributary Totó River that belong to Upper Iguaçu Basin, southern Brazil. Two collection points were established along the main channel of Negro River, in a 7.00 km long stretch, and three points in the entire creek Totó River with 6.61 km long. The animals were captured with Surber net and baited traps and had the carapace length (CL) measured. A total 146 crabs were obtained from Negro River and 361 from Totó River, performing 507 analyzed aeglids. From the point 1 of Negro River, males measured 27.68 ± 12.68 mm CL and females 18.98 ± 5.88 mm CL; from point 2 of the same river, the values were 24.45 ± 13.70 mm CL and 27 ± 8.50 mm CL, respectively. There was a positive and direct relationship between the mean CL of the aeglids from Totó River and the distance of the collection points from its source. Males: point 1 (source of the creek): 7.90 ± 1.23 mm CL; point 2: 9.55 ± 3.06 mm CL; point 3: 9.91 ± 2.62 mm CL. Females: point 1 (source): 6.68 ± 1.70 mm CL; point 2: 9.01 ± 1.94 mm CL; point 3: 10.49 ± 2.57 mm CL. The sexually immature aeglids are distributed mainly in the lower order tributary (= Totó River), and the mature ones in the main channel of Negro River, indicating that this population perform ontogenetic migrations from tributary to the main river. The spatial partition can be explained under three aspects that are quite contrasting between Negro River and Totó River: 1. substrate architecture; 2. depth of the water column and 3. quality of available food.(AU)

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Introducción: El proceso de invasión biológica es una de las mayores amenazas a la biodiversidad y ecosistemas, con actuales y potenciales impactos en la salud pública y conservación. Procambarus clarkii es un crustáceo decápodo, originario del sur de Estados Unidos y noreste de México, que puede adaptarse a diferentes condiciones ambientales debido a su plasticidad ecológica. Objetivo: Se caracterizó el nicho ecológico fundamental existente de Procambarus clarkii con el fin de predecir las áreas con idoneidad ambiental para el potencial establecimiento de la especie en Suramérica y Colombia. Métodos: Usamos modelos de nichos ecológicos calibrados en el área nativa, elaborados con el algoritmo Maxent, basados en datos de presencia extraídos de GBIF y variables hidroclimáticas de ecosistemas acuáticos a una resolución de 1 km2. Resultados: En Suramérica el modelo indicó un potencial geográfico amplio de invasión mostrando áreas ambientalmente idóneas para la presencia y expansión hacia Colombia, Venezuela, Perú, Ecuador, Brasil, Guyana, Surinam, Bolivia, Uruguay, Argentina, Paraguay y Chile. En Colombia, el modelo predijo que las áreas idóneas se ubican principalmente en el norte y oriente, incluidos diversos ecosistemas, como: bosques tropicales, bosques basales, bosques riparios y sabanas. La especie tiene una alta posibilidad de expandirse hacia áreas de distribución de latitudes bajas, ocupando zonas hacia la parte norte de la región Caribe colombiana, en departamentos de Magdalena, Cesar, Córdoba y Atlántico. También se predijo áreas con idoneidad ambiental en el oriente de Colombia, hacia la extensión de la planicie oriental de la Orinoquia, una región de baja altitud en: Arauca, Casanare, Meta y Vichada. Conclusión: En este estudio se aplican modelos de nichos ecológicos, que puede ser de interés en la planeación de estrategias o la creación de planes de manejo, como sistemas de alerta temprana para evitar el establecimiento de esta especie.

Introduction: Biological invasions are a major threat to biodiversity and ecosystems, with current and potential impacts on public health and conservation. Procambarus clarkii is a decapod crustacean, native to the Southern United States and Northeastern Mexico, which may adapt to different environmental conditions due to its ecological plasticity. Objective: The existing fundamental ecological niche of Procambarus clarkii was characterized in order to predict areas with environmental suitability for the potential establishment of the species in South America and Colombia. Methods: We used models of calibrated ecological niches in the native area, elaborated with the Maxent algorithm, based on occurrence data extracted from GBIF and hydroclimatic variables of aquatic ecosystems at a resolution of 1 km2. Results: The model indicated a wide geographic area for invasion potential in South America, predicting environmentally suitable areas for the presence and expansion towards Colombia, Venezuela, Peru, Ecuador, Brazil, Guyana, Surinam, Bolivia, Uruguay, Argentina, Paraguay and Chile. In Colombia, suitable areas predicted by the model are located mainly in the North and East of the country, spanning a diversity of ecosystems, such as tropical forests, basal forests, riparian forests and savannas. The species has a high possibility of expanding into low latitude distribution areas, occupying areas towards the Northern part of the Colombian Caribbean region, in the departments of Magdalena, Cesar, Cordoba and Atlántico. Suitability areas environmental were also predicted in Eastern Colombia, towards the extension of the Eastern plain of the Orinoquia, a low altitude region in Arauca, Casanare, Meta and Vichada. Conclusion: This study applies ecological niche models, which may be of interest in the planning of strategies or the creation of management plans, such as early warning systems that prevent the establishment of this species.

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This study evaluated the protein requirement of Litopenaeus vannamei post-larvae during the initial rearing phase in a biofloc system. Five different diets were evaluated with increasing concentrations of crude protein: 31.28, 36.29, 41.57, 46.34, and 51.74 g 100 g-¹ CP. Post-larvae (0.16 ± 0.01 g) were stocked at a density of 450 PL m-³ in 400 L tanks. Water quality parameters were maintained within the limits recommended for shrimp farming. After 38 days, a regression analysis revealed that levels of CP content (65.29–72.83%), EE (10.45–11.65%) and body N (10.45–11.64%) increased with increasing protein levels in the diet. A similar trend was observed in the biofloc sludge with respect to CP and N. Survival exceeded 80%, and the shrimp with diets containing 31.28 to 46.34 g 100 g-¹ CP presented an increase in final weight (1.52–2.61 g), productivity (0.69–1.10 kg m-³), weight gain (1.38–2.44 g), and feeding efficiency (77.28–101.68%), whereas these indices decreased to 51.74 g 100 g-¹ CP. Crude protein content from 44.26 to 47.12 g 100 g-¹ provided the best growth performance during the initial rearing phase of Pacific white shrimp L. vannamei in a biofloc system.

Esse estudo avaliou a exigência proteica do Litopenaeus vannamei na fase inicial de cultivo em sistema de bioflocos. Cinco dietas com quantidades crescentes de proteína bruta (31,28; 36,29; 41,57; 46,34 e 51,74 g 100 g-¹ PB) foram avaliadas. As pós-larvas (0,16 ± 0,01 g) foram estocadas na densidade de 450 PL m-³ em tanques de 400 L. A qualidade de água manteve-se dentro dos limites adequados para o cultivo. Após 38 dias, uma análise de regressão revelou que teores de PB (65,29–72,83%), EE (10,45–11,65%) e N corporal (10,45–11,64%) aumentaram com os níveis crescente de proteína na dieta. A mesma análise foi realizada para o lodo do bioflocos, que apresentou aumento crescente de PB e N. A sobrevivência foi superior a 80% e os camarões alimentados com dietas contendo 31,28 à 46,34g 100 g-¹ PB obtiveram aumento no peso final (1,52–2,61 g), produtividade (0,69–1,10 kg m-³), ganho em peso (1,38–2,44 g) e eficiência alimentar (77,28–101,68%), enquanto esses índices decresceram no tratamento 51,74 g 100 g-¹ PB. O conteúdo de proteína bruta entre 44,26 à 47,12 g 100 g-¹ PB proporcionou o melhor desempenho de crescimento durante a fase inicial do cultivo do camarão-branco-do-pacífico L. vannamei em bioflocos.

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This study evaluated the protein requirement of Litopenaeus vannamei post-larvae during the initial rearing phase in a biofloc system. Five different diets were evaluated with increasing concentrations of crude protein: 31.28, 36.29, 41.57, 46.34, and 51.74 g 100 g-¹ CP. Post-larvae (0.16 ± 0.01 g) were stocked at a density of 450 PL m-³ in 400 L tanks. Water quality parameters were maintained within the limits recommended for shrimp farming. After 38 days, a regression analysis revealed that levels of CP content (65.29–72.83%), EE (10.45–11.65%) and body N (10.45–11.64%) increased with increasing protein levels in the diet. A similar trend was observed in the biofloc sludge with respect to CP and N. Survival exceeded 80%, and the shrimp with diets containing 31.28 to 46.34 g 100 g-¹ CP presented an increase in final weight (1.52–2.61 g), productivity (0.69–1.10 kg m-³), weight gain (1.38–2.44 g), and feeding efficiency (77.28–101.68%), whereas these indices decreased to 51.74 g 100 g-¹ CP. Crude protein content from 44.26 to 47.12 g 100 g-¹ provided the best growth performance during the initial rearing phase of Pacific white shrimp L. vannamei in a biofloc system.(AU)

Esse estudo avaliou a exigência proteica do Litopenaeus vannamei na fase inicial de cultivo em sistema de bioflocos. Cinco dietas com quantidades crescentes de proteína bruta (31,28; 36,29; 41,57; 46,34 e 51,74 g 100 g-¹ PB) foram avaliadas. As pós-larvas (0,16 ± 0,01 g) foram estocadas na densidade de 450 PL m-³ em tanques de 400 L. A qualidade de água manteve-se dentro dos limites adequados para o cultivo. Após 38 dias, uma análise de regressão revelou que teores de PB (65,29–72,83%), EE (10,45–11,65%) e N corporal (10,45–11,64%) aumentaram com os níveis crescente de proteína na dieta. A mesma análise foi realizada para o lodo do bioflocos, que apresentou aumento crescente de PB e N. A sobrevivência foi superior a 80% e os camarões alimentados com dietas contendo 31,28 à 46,34g 100 g-¹ PB obtiveram aumento no peso final (1,52–2,61 g), produtividade (0,69–1,10 kg m-³), ganho em peso (1,38–2,44 g) e eficiência alimentar (77,28–101,68%), enquanto esses índices decresceram no tratamento 51,74 g 100 g-¹ PB. O conteúdo de proteína bruta entre 44,26 à 47,12 g 100 g-¹ PB proporcionou o melhor desempenho de crescimento durante a fase inicial do cultivo do camarão-branco-do-pacífico L. vannamei em bioflocos.(AU)

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Introduction: Sporadic aggregations of decapod crustaceans can occur for various reasons and in some cases their drivers are poorly understood. Objective: Here, we present our observations of an apparently rare massive aggregation of pelagic swimming crabs, Euphylax dovi. Methods: During a research cruise at Cocos Island (5°32'34" N, 87°05'06" W), we encountered large numbers of E. dovii in surface waters in the evenings of May 6-7, 2015, some of which we collected for identification prior to returning to the water. Results: Crabs of both sexes were identified, yet no females were bearing eggs. Crabs aggregated around a small dinghy used for scientific surveying from 4pm through 8pm each evening, and around our research vessel throughout the night, presumably attracted by the lights. On both occasions, the aggregation dissipated around dawn. Crabs were not seen prior to or after the two nights. Conclusions: Sea surface temperatures at Cocos during this period were markedly warm, with no perceptible thermocline down to at least 40 m, coinciding with the onset of the 2015 El Niño event. It appears that the aggregation formed in response to El Niño conditions, yet the biological reason behind it remains unknown.

Introducción: Las agregaciones esporádicas de crustáceos decápodos ocurren por varias razones, y en algunos casos no se conocen los factores que las provocan. Objetivos: En esta publicación presentamos nuestras observaciones sobre un evento aparentemente no muy común, de una agregación masiva de cangrejos pelagicos Euphylax dovii. Métodos: Durante una expedición científica a Isla del Coco (5°32'34" N, 87°05'06" W), encontramos grandes cantidades de cangrejos pelágicos en las aguas superficiales en las noches del 6 al 7 de mayo, 2015. Colectamos algunos individuos para identificarlos antes de liberarlos nuevamente. Resultados: Identificamos cangrejos de ambos sexos, pero ninguna hembra en estado ovígero. Los cangrejos se agregaron alrededor de una pequeña panga que utilizamos para realizar actividades de muestreo científico entre las 4pm y las 8 pm cada tarde, y alrededor de nuestro buque de investigación durante la noche, presumiblemente atraídos por las luces. En ambas ocasiones, la agregación disipó antes del amanecer. No se avistaron cangrejos en las noches anteriores o posteriores. Conclusiones: Las temperaturas superficiales marinas en Isla del Coco durante este periodo fueron altas, sin termoclina hasta al menos 40 m, coincidiendo con el inicio del evento El Niño de 2015. Parece que la agregación se formó en respuesta a las condiciones del Niño, pero las razones biológicas dicha agregación no se conocen.

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Introduction: Crustaceans have economic and ecological importance and the role of caridean crustaceans in lentic environments is crucial to maintain the trophic structure. The species Atya scabra is occasionally associated with fisheries, especially in Northeast and Northern Brazil. Objective: To determine the population structure, reproductive period, patterns of growth and distribution of size classes among sexes in a population of the prawn A. scabra in the De Contas River, Bahia, Brazil. Methods: Individuals were sampled in a period of one year by passing sieves through marginal vegetation and using dragnets. In the laboratory, we recorded the sex of the individuals and measured them using a pachymeter with 0.001 mm precision. The dimensions measured were CL (carapace length), TL (total length) and CW (carapace width). In order to analyze data, linear models for the relationships CL × CW were constructed and the type of allometry for each sex was determined. Individuals were grouped into size classes of 5 mm intervals. A chi-square test (χ2) was used to test deviation from the 1:1 sex ratio. The proportion of ovigerous females was registered for each month to determine the breeding period. Results: A total of 517 individuals were collected, 328 were males and 186 females of which 169 were ovigerous. Males showed a polymodal distribution in size classes and were significantly larger than females, which presented a unimodal distribution in size classes. The observed growth patterns demonstrated that both sexes present negative allometry. However, sexual dimorphism was detected when comparing the growth parameters. Ovigerous females were sampled the entire year and size-frequency data demonstrated that recruitment also occurs throughout the year, which allowed us to classify their reproduction as continuous. Conclusions: Our data is essential to draw sustainable fishery management strategies. We suggest a minimum capture size of 70 mm and capture restrictions from May to August.

Introducción: Los crustáceos tienen importancia económica y ecológica y el papel de los crustáceos carideanos en los entornos lénticos es crucial para mantener la estructura trófica. La especie Atya scabra se asocia ocasionalmente con la pesca, especialmente en el noreste y norte de Brasil. Objetivo: Determinar la estructura de la población, período reproductivo, patrones de crecimiento y la distribución de las clases de tamaño entre los sexos en una población de gambas A. scabra en el río de Contas, Bahía, Brasil. Métodos: Se tomaron muestras de los individuos en un período de un año pasando tamices en la vegetación marginal y usando redes de arrastre (dragnets). En el laboratorio, registramos el sexo de los individuos y los medimos utilizando un paquímetro con precisión de 0.001 mm. Las dimensiones medidas fueron CL (longitud del caparazón), TL (longitud total) y CW (ancho del caparazón). Para analizar los datos, se construyeron modelos lineales para las relaciones CL × CW y se determinó el tipo de alometría para cada sexo. Los individuos se agruparon en clases de tamaño de intervalos de 5 mm. La prueba de chi-cuadrado (χ2) se utilizó para determinar desviaciones en la proporción de sexos 1:1. La proporción de hembras ovígeras se registró en cada mes para determinar el período de reproducción. Resultados: Se recolectaron un total de 517 individuos, 328 machos y 186 hembras, de las cuales 169 eran ovígeras. Los machos mostraron una distribución polimodal en las clases de tamaño y fueron significativamente más grandes que las hembras, las cuales presentaron una distribución unimodal en las clases de tamaño. Los patrones de crecimiento observados demostraron que ambos sexos presentan alometría negativa. Sin embargo, se detectó dimorfismo sexual al comparar los parámetros de crecimiento. Se tomaron muestras de hembras ovígeras durante todo el año y los datos de frecuencia de tamaño demostraron que el reclutamiento también se produce durante todo el año, lo que nos permitió clasificar la reproducción como continua. Conclusiones: Nuestros datos son esenciales para elaborar estrategias sostenibles de gestión pesquera. Sugerimos un tamaño mínimo de captura de 70 mm y restricciones de captura desde mayo hasta agosto.

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Assessments of the effectiveness of marine protected areas (MPAs) usually assume that fishing patterns change exclusively due to the implementation of an MPA. This assumption increases the risk of erroneous conclusions in assessing marine zoning, and consequently counter-productive management actions. Accordingly, it is important to understand how fishers respond to a combination of the implementation of no-take zones, and various climatic and human drivers of change. Those adaptive responses could influence the interpretation of assessment of no-take zone effectiveness, yet few studies have examined these aspects. Indeed, such analysis is often unfeasible in developing countries, due to the dominance of data-poor fisheries, which precludes full examination of the social-ecological outcomes of MPAs. In the Galapagos Marine Reserve (Ecuador), however, the availability of long-term spatially explicit fishery monitoring data (1997-2011) for the spiny lobster fishery allows such an analysis. Accordingly, we evaluated how the spatiotemporal allocation of fishing effort in this multiple-use MPA was affected by the interaction of diverse climatic and human drivers, before and after implementation of no-take zones. Geographic information system modelling techniques were used in combination with boosted regression models to identify how these drivers influenced fishers' behavior. Our results show that the boom-and-bust exploitation of the sea cucumber fishery and the global financial crisis 2007-09, rather than no-take zone implementation, were the most important drivers affecting the distribution of fishing effort across the archipelago. Both drivers triggered substantial macro-scale changes in fishing effort dynamics, which in turn altered the micro-scale dynamics of fishing patterns. Fishers' adaptive responses were identified, and their management implications analyzed. This leads to recommendations for more effective marine and fishery management in the Galapagos, based on improved assessment of the effectiveness of no-take zones.

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The aim of the present study was to evaluate the influence of abiotic factors (conductivity, dissolved oxygen, pH, precipitation, and water temperature) on the abundance of Macrobrachium amazonicum (Heller, 1862), as well as to compare the relative growth among demographic groups throughout the seasons in a lagoon system located in the municipality of Perdões, Minas Gerais. Monthly, from August/2013 to July/2014, the prawns were collected on macrophytes of the genus Eichhornia using a semi-circular sieve. In the laboratory, the specimens were categorized into juveniles, males, ovigerous females and non-ovigerous females, and measured as total length (TL), carapace length (CL), and abdomen length (AL). The predominance of juveniles was evident, representing 74.4%, followed by 16.7% males, 2.8% ovigerous females and 6.1% non-ovigerous females. The total abundance and the abundance of juveniles, males, and females were negatively correlated with conductivity. [...] The highest abundance of juveniles can be related to its occurrence in microhabitats that provide refuge, as Eichhornia. Despite some similar characteristics here observed in relation to the other populations throughout its distribution, as the high number of juveniles and the smaller size of males compared to females, the present study provides information that expands the knowledge on the plasticity of M. amazonicum, considering the sampled local - a lateral lagoon system. The obtained results promote the comprehension of the vast occurrence of the species and its adaptations to each specific environment, contributing to the elaboration of conservation and management guidelines for M. amazonicum and for the environment where it inhabits.(AU)

O objetivo do presente estudo foi avaliar a influência de fatores abióticos (condutividade, oxigênio dissolvido, pH, precipitação e temperatura da água) na abundância de Macrobrachium amazonicum (Heller, 1862), bem como comparar o crescimento relativo entre as categorias demográficas ao longo das estações do ano, em uma lagoa marginal localizada no município de Perdões, em Minas Gerais. Os camarões foram coletados mensalmente, de agosto de 2013 a julho de 2014, em macrófitas do gênero Eichhornia com o uso de uma peneira semicircular. [...] A abundância total e a abundância de juvenis, machos e fêmeas foram correlacionadas negativamente com a condutividade. O crescimento relativo do CT e CA, em relação ao CC, foi diferente para juvenis, machos e fêmeas ao longo de todo ano, exceto durante o verão (para CT e CA) e o outono (para CA), quando o mesmo padrão foi observado para as três categorias demográficas (p>0,05), possivelmente devido à maior abundância de indivíduos jovens obtida durante estas estações. Esta maior abundância de juvenis pode estar relacionada à sua ocorrência em microhabitats que forneçam refúgio como Eichhornia. Apesar de algumas características semelhantes aqui observadas em relação às demais populações ao longo de sua distribuição geográfica, como o elevado número de juvenis e o menor tamanho dos machos em comparação às fêmeas, o presente estudo fornece informações que ampliam o conhecimento sobre a plasticidade de M. amazonicum, principalmente com relação ao local de amostragem - uma lagoa marginal. Desta forma, os resultados obtidos ampliam a compreensão sobre a vasta ocorrência da espécie e suas respectivas adaptações nos mais variados habitats, contribuindo para a elaboração de diretrizes de conservação e manejo para M. amazonicum e para o meio que habita.(AU)

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Species loss from upper trophic levels can result in some major changes in community structure and ecosystem functions. Here, we experimentally excluded macroconsumers (e.g., fish and shrimp) in a Brazilian karst tropical stream during the dry season to investigate if their loss affected the accrual of calcium, dry mass (DM) and ash-free dry mass (AFDM) of sediment, benthic invertebrates, and chlorophyll-a. We found that the exclusion of macroconsumers decreased accrual of calcium. The absence of fish and shrimp may have promoted increased grazing by mayflies and snails in the electrified treatment as expressed by the depressed calcium accrual and shift in periphyton community composition. However, the exclusion of macroconsumers had no effect on DM and AFDM, chlorophyll-a, or total abundance of invertebrates. Our findings shed new light on the impact of macroconsumer loss and consequences for calcium accrual in karstic streams.

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A study on relative growth, sexual dimorphism and ontogenetic trajectory was carried out in a population of the aeglidAegla marginata coming from Barrinha River, Iguape River Basin, Tunas do Paraná, Paraná State, Brazil. The size the of morphological sexual maturity was estimated for males and females. The analysis of sexual dimorphism and ontogenetic trajectory were performed using geometric morphometric technique. Males reach maturity with 10.58 mm of carapace length (CL) and females with 10.38 mm CL. Sexual size dimorphism was only visible among adults, with males reaching larger sizes. This is probably related to the reproductive strategy of males. However, sexual shape dimorphism was found for both juveniles and adults: the posterior region of the carapace was wider in females. As the contrast of this feature was stronger in adults, it can be considered that large abdomen is advantageous for egg incubation. The allometric trajectories of juveniles presented similar directions, becoming divergent during the adult phase. The shape variation inA. marginataoccurred gradually throughout its development, with no abrupt transformation upon reaching sexual maturity. The reproductive adaptation is the main reason for the morphological variation within populations ofA. marginata.

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Although larval stages are often considered particularly vulnerable to stressors, for many marine invertebrates studies of thermal tolerance have focused on adults. Here we determined the upper thermal limit (LT50) of the zoea I of four Caribbean crab species (Macrocoeloma trispinosum, Aratus pisonii, Armases ricordi, and Minuca rapax) and compared their thermal tolerance over time and among species. The zoea from the subtidal species M. trispinosum and tree climbing mangrove species A. pisonii had a lower thermal tolerance, 35 and 38.5 °C respectively, than did the semiterrestrial A. ricordi and M. rapax. In all four species tested, the estimates of thermal tolerance depend on the duration of exposure to elevated temperatures. Longer exposures to thermal stress produce lower estimates of LT50, which decreased by ~1 °C from a two- to a six-hour exposure. Crab embryos develop on the abdomen of the mother until the larvae are ready to hatch. Therefore, the thermal tolerances of the embryos which need to coincide with the environmental conditions experienced by the adult stage, may carry over into the early zoea stage. Our results suggest that semiterrestrial species, in which embryos may need to withstand higher temperatures than embryos of subtidal species also produce larvae with higher thermal tolerances. Over the short term, the larvae of these tropical crab species can withstand significantly higher temperatures than those experienced in their marine habitat. Longer term rearing studies are necessary to determine the temperature at which chronic exposure has a negative impact on embryonic and larval survival.

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Although larval stages are often considered particularly vulnerable to stressors, for many marine invertebrates studies of thermal tolerance have focused on adults. Here we determined the upper thermal limit (LT50) of the zoea I of four Caribbean crab species (Macrocoeloma trispinosum, Aratus pisonii, Armases ricordi, and Minuca rapax) and compared their thermal tolerance over time and among species. The zoea from the subtidal species M. trispinosum and tree climbing mangrove species A. pisonii had a lower thermal tolerance, 35 and 38.5 °C respectively, than did the semiterrestrial A. ricordi and M. rapax. In all four species tested, the estimates of thermal tolerance depend on the duration of exposure to elevated temperatures. Longer exposures to thermal stress produce lower estimates of LT50, which decreased by ~1 °C from a two- to a six-hour exposure. Crab embryos develop on the abdomen of the mother until the larvae are ready to hatch. Therefore, the thermal tolerances of the embryos which need to coincide with the environmental conditions experienced by the adult stage, may carry over into the early zoea stage. Our results suggest that semiterrestrial species, in which embryos may need to withstand higher temperatures than embryos of subtidal species also produce larvae with higher thermal tolerances. Over the short term, the larvae of these tropical crab species can withstand significantly higher temperatures than those experienced in their marine habitat. Longer term rearing studies are necessary to determine the temperature at which chronic exposure has a negative impact on embryonic and larval survival.(AU)

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Three new species of freshwater crabs of the genus Pseudothelphusa (De Saussure, 1857) from south-central Mexico are described: Pseudothelphusa acahuizotla n. sp., P. ixtapan n. sp., and P. purhepecha n. sp. The new species are included in Pseudothelphusa due to a male gonopod with torsion and the presence of the characteristic mesial process and caudomarginal projection. Pseudothelphusa acahuizotla n. sp. is morphologically similar to P. belliana Rathbun, 1898, but can be distinguished by the relative size of the distal lobe of the caudomarginal projection and by the presence of a conical tooth on the caudal surface of the mesial process of the male gonopod. Pseudothelphusa ixtapan n. sp. is similar to P. dilatata Rathbun, 1898, and P. morelosis Pretzmann, 1968, and can be distinguished by a mesial process of the male gonopod with only one lateral tooth and an inferior margin with small teeth. Pseudothelphusa puerhepechae n. sp. exhibits a mesial process of the male gonopod with two triangular spines on its lateral margin, a character that with some variations is present in P. nayaritae Álvarez & Villalobos, 1994, P. rechingeri Pretzmann, 1965, P. lophophallus Rodríguez & Smalley, 1969, and P. parabelliana Álvarez 1989; but it can be distinguished by the separation and shape of the two spines of the mesial process and the shape of the lobes of the caudomarginal projection. With the new species described herein there are now 29 species in the genus Pseudothelphusa.

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A preliminary assessment of the deep-sea Decapoda is proposed for Guadeloupe Island based solely on high definition macro photographs taken during the KARUBENTHOS 2015 Expedition to the Island (R/V Antea, 7-29 June 2015). Overall, 190 species are recognized, several of which are depicted with their fresh color for the first time. Previous records in the Lesser Antilles are documented and the geographic distribution of the species in these Islands is given. The historical contribution of the steamer Blake (1878-1879) in the Lesser Antilles is emphasized. All species inventoried during KARUBENTHOS 2015 were already reported in the western Atlantic but 34 of them are new records for the Lesser Antilles and 116 are reported for the first time from Guadeloupe Island. This preliminary inventory is estimated to include about 38% of the deep-sea Decapoda potentially occurring around Guadeloupe Island.

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The first stage of the fiddler crab Minuca mordax is described here. Zoea larvae obtained from four ovigerous female were reared in the laboratory until the development of the first crab stage. The development from zoea I to the first juvenile instar lasted 35 days after hatching. The first crab stage of Minuca mordax can be morphologically distinguished from those of Minuca burgersi and Leptuca cumulanta by a 2segmented antennule endopod (3segmented in M. burgersi, unsegmented in L. cumulanta), an unsegmented maxillule endopod (2segmented in M. burgersi and L. cumulanta), and a 4segmented first and second maxilliped endopod (respectively unsegmented and 5segmented in M. burgersi and L. cumulanta). The three species have the following characters in common: segmented peduncle of antennule 2; endopod of antennule unsegmented; presence of aesthetascs on the antennule; peduncle of antenna 3segmented; flagellum of antenna 6segmented; mandible 3segmented; maxilla with coxal and basal endite bilobed; first, second and third maxillae with exopod 2segmented and abdomen with six somites that are wider than long.

O primeiro estágio juvenil do caranguejo chama-maré Minuca mordax foi descrito. Larvas zoea foram obtidas de fêmeas ovígeras e cultivadas em laboratório até atingir o primeiro estágio juvenil. O desenvolvimento de zoea I até o primeiro estágio juvenil teve duração de 35 dias após a eclosão. O cultivo foi mantido em um aquário com salinidade 20‰, sob fotoperíodo (claro: escuro/12:12) e temperatura (25°C) constante. Os juvenis foram dissecados e os apêndices desenhados e descritos. O primeiro estágio juvenil de M. mordax pode ser morfologicamente distinto do mesmo estágio de M. burgersi and L. cumulanta por apresentar antênula com endopodito bisegmentado (3-segmentos em M. burgersi, não segmentado em L. cumulanta), maxílula com endopodito não segmentado (2-segmentos em M. burgersi e L. cumulanta), e primeiro e segundo maxilípodo com endopodito 4-segmentado (respectivamente não segmentado e 5-segmentos em M. burgersi e L. cumulanta). Os seguintes caracteres são comuns a estas três espécies: pedúnculo da antênula bissegmentado; antênula com endopodito não segmentado; presença de estetascos na antênula; pedúnculo da antena trisegmentado; flagelo da antena 6-segmentado; mandíbula trisegmentada; maxila com coxal e basal endito bilobado; primeira, segunda e terceira maxila com exopodito bissegmentado e abdômen com seis somitos que são mais largos do que longos.

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The first stage of the fiddler crab Minuca mordax is described here. Zoea larvae obtained from four ovigerous female were reared in the laboratory until the development of the first crab stage. The development from zoea I to the first juvenile instar lasted 35 days after hatching. The first crab stage of Minuca mordax can be morphologically distinguished from those of Minuca burgersi and Leptuca cumulanta by a 2segmented antennule endopod (3segmented in M. burgersi, unsegmented in L. cumulanta), an unsegmented maxillule endopod (2segmented in M. burgersi and L. cumulanta), and a 4segmented first and second maxilliped endopod (respectively unsegmented and 5segmented in M. burgersi and L. cumulanta). The three species have the following characters in common: segmented peduncle of antennule 2; endopod of antennule unsegmented; presence of aesthetascs on the antennule; peduncle of antenna 3segmented; flagellum of antenna 6segmented; mandible 3segmented; maxilla with coxal and basal endite bilobed; first, second and third maxillae with exopod 2segmented and abdomen with six somites that are wider than long.(AU)

O primeiro estágio juvenil do caranguejo chama-maré Minuca mordax foi descrito. Larvas zoea foram obtidas de fêmeas ovígeras e cultivadas em laboratório até atingir o primeiro estágio juvenil. O desenvolvimento de zoea I até o primeiro estágio juvenil teve duração de 35 dias após a eclosão. O cultivo foi mantido em um aquário com salinidade 20‰, sob fotoperíodo (claro: escuro/12:12) e temperatura (25°C) constante. Os juvenis foram dissecados e os apêndices desenhados e descritos. O primeiro estágio juvenil de M. mordax pode ser morfologicamente distinto do mesmo estágio de M. burgersi and L. cumulanta por apresentar antênula com endopodito bisegmentado (3-segmentos em M. burgersi, não segmentado em L. cumulanta), maxílula com endopodito não segmentado (2-segmentos em M. burgersi e L. cumulanta), e primeiro e segundo maxilípodo com endopodito 4-segmentado (respectivamente não segmentado e 5-segmentos em M. burgersi e L. cumulanta). Os seguintes caracteres são comuns a estas três espécies: pedúnculo da antênula bissegmentado; antênula com endopodito não segmentado; presença de estetascos na antênula; pedúnculo da antena trisegmentado; flagelo da antena 6-segmentado; mandíbula trisegmentada; maxila com coxal e basal endito bilobado; primeira, segunda e terceira maxila com exopodito bissegmentado e abdômen com seis somitos que são mais largos do que longos.(AU)

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ResumenPara la jaiba café (Callinectes bellicosus) capturada en Sonora, México dentro del Golfo de California desde 1986, durante 20 años se ha observado una tendencia decreciente en la biomasa. Se estimaron las tasas de crecimiento poblacional (r) y proporción de sexos de C. bellicosus además de tres parámetros que describen su hábitat: temperatura del mar, extensión de humedales y tamaño del hábitat en cuatro zonas a lo largo de la costa de Sonora. La proporción de sexos se estimó de 25 556 jaibas muestreadas de las capturas comerciales en los años 19982002 y 2012; la temperatura media en el período de desove (mayo-agosto) se generó a partir de sensores remotos en los mismos años; la cobertura de humedales se obtuvo de reportes publicados; y el tamaño del hábitat se estimó como la superficie de pesca. Para cada zona se estimó r mediante un método desarrollado para situaciones de escasa información utilizando las capturas comerciales (t) de 1986 a 2013. Con los datos de las cuatro zonas se desarrollaron modelos de regresión lineal simple y múltiple para evaluar las sensibilidades teóricas de r a variaciones en la proporción de sexos y en los parámetros ambientales. Los machos dominaron (68.8 %) sobre las hembras en el período de estudio en las cuatro zonas; un análisis de conglomerados identificó dos grupos de acuerdo a la proporción de sexos: un grupo norteño con las zonas 1 y 2, y otro sureño con las zonas 3 y 4. Los valores de r fueron diferentes en las cuatro zonas (P<0.001) igual que la proporción de sexos (P=0.037); no se encontraron diferencias en la temperatura entre los años considerados en el estudio (P>0.995). Tanto los datos estimados como los análisis de sensibilidad sugieren que r dependen directa y positivamente de la proporción de hembras de jaiba y el tamaño de los humedales. Por lo anterior planteamos la hipótesis de que la pesca excesiva de hembras es la causa del descenso de la biomasa de jaiba café en Sonora, y concluimos que es conveniente implementar refugios pesqueros dentro de humedales costeros para proteger las hembras en el período de desove.

Abstract:The brown swimming crab (Callinectesbellicosus) is an economically important species in the Gulf of California, and its fishing activity, held in Sonora from 1986, has been affected by a 20-year declining trend in its biomass. With the aim to understand the possible reasons of this species population changes along time, we estimated population growth rate (r) and sex ratio of C. bellicosus, and combined them with three parameters describing its habitat: sea temperature, wetland extension and habitat size in four areas along the coast of Sonora. For this, monthly mean sex ratio was estimated from crabs samples obtained from commercial catches during 1998-2002 and 2012; mean sea surface temperature for the spawning period (May-August) were derived from remote sensors for the same years; while wetland coverages were obtained from published reports, and habitat size was estimated as the fishing surface. For each area, r was estimated using a method developed for limited data situations using commercial landings (t) from 1986-2013. With data from the four areas, simple and multiple linear regression models were developed to ascertain theoretical sensitivities of r to variations in sex ratio and environmental parameters. A total of 24 556 crabs were sampled; males dominated (68.8 %) over females during the study period and in all areas; a cluster analysis identified two groups according to sex ratio: a Northern group with zones 1 and 2, and a Southern group with zones 3 and 4. r values were different in all zones (P<0.001) as was sex ratio (P=0.037); no differences in temperature were identified within the study years (P>0.995). Both the estimated data and sensitivity analyses suggest the existence of a direct and positive dependence of r on the proportion of female crabs and wetland size. We hypothesize that excess fishing of females caused the declining biomass trend of the brown swimming crab in Sonora, and concluded on the convenience of implementing harvest refugia inside coastal wetlands to protect females during the spawning season. Rev. Biol. Trop. 64 (3): 1259-1271. Epub 2016 September 01.

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The present study deals with shrimps of the family Alpheidae collected in the shallow waters around the remote Trindade & Martin Vaz Archipelago, situated 1200 km off the coast of Espírito Santo, Brazil. A few additional samples came from dredges on top of the seamounts of the Vitória-Trindade Seamount Chain. A total of 23 species in eight genera are reported, the vast majority representing new records for the area. One species is described as new, Synalpheus trinitatis sp. nov., based on the type material from Trindade Island. The new species clearly belongs to the Synalpheus brooksi Coutière, 1909 species complex, differing from all its other members by at least two morphological features. Four species represent new records for Brazil and the southwestern Atlantic: Alpheopsis aequalis Coutière, 1897 sensu lato, Alpheopsis chalciope de Man, 1910 sensu lato, Alpheus crockeri (Armstrong, 1941) and Prionalpheus gomezi Martínez-Iglesias & Carvacho, 1991; the two species of Alpheopsis are recorded from the Atlantic Ocean for the first time. The colour pattern of the recently described Alpheus rudolphi Almeida & Anker, 2011, a species endemic to Brazil, is shown for the first time and compared to the colour patterns of the four closely related species of the A. armatus Rathbun, 1901 complex from the Caribbean-Florida region. A brief zoogeographical analysis of the alpheid fauna of the oceanic islands of the tropical southern Atlantic (Trindade & Martin Vaz, Fernando de Noronha, Atol das Rocas, São Pedro & São Paulo, Ascension, Saint Helena, Cape Verde, São Tomé & Príncipe) is also provided.

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