Purus River Research Articles

Polymorphic microsatellite markers for the overexploited Amazonian fish, Semaprochilodus insignis (Jardine and Schomburgk 1841)

We used a microsatellite-enriched library to isolate and characterize 16 di-nucleotide microsatellite loci in Semaprochilodus insignis. Microsatellites were characterized in a population sample from Piagacu-Purus (Purus River, Amazonas, Brazil) and in eight individuals each of S. brama from Itaipavas (Araguaia River, Para, Brazil), S. taeniurus from Novo Airao (Negro River, Amazonas, Brazil), S. kneri (Caura River, Venezuela), and Prochilodus nigricans also from Piagacu-Purus. In S. insignis observed heterozygosities ranged from 0.516 to 0.968, expected heterozygosities from 0.574 to 0.973, and the number of alleles per locus varied from 4 to 32 in 31 analyzed individuals. All loci were unlinked and three loci showed significant deviations from Hardy–Weinberg equilibrium. Most markers could be successfully transferred to the other four prochilodontids, making them potentially useful for conservation genetic studies of Semaprochilodus spp.

Structure and dynamics of stream fish communities in the flood zone of the lower Purus River, Amazonas State, Brazil

The structure and dynamics of fish communities were characterized by richness, abundance, diversity and stability, during high-water and low-water periods. These analyses were performed on data from the flood zone of four streams in the lower Purus River, in the Brazilian Amazon. A total of 188 species of fish were collected, distributed among 29 families and eight orders. The statistical test showed a difference in community diversity between periods. The high-water period showed higher evenness in comparison to the low-water season. The low-water period was marked by high species abundance. A great variation in community composition between the flood and low-water periods was encountered. The adjustments for species abundance models suggested that stochastic events structure the communities. Most of the species showed a temporal variation of abundance indicating low community stability. Changes in the physico-chemical conditions of the water caused by the seasonal hydrological regime may be influencing the structuring of the fish communities.

Caracterização de geoambientes da floresta nacional do purus, Amazônia ocidental: uma contribuição ao plano de manejo

A falta de estudos básicos necessários para o plano de manejo vem retardando a implementação efetiva de diversas Unidades de Conservação na região amazônica. Neste trabalho, interpretações de imagens orbitais e semiorbitais aliadas a trabalhos de campo foram utilizadas para a caracterização geoambiental da Floresta Nacional (FLONA) do Purus. Através da geração de mapas temáticos, criou-se uma base digital georreferenciada que constitui a primeira plataforma para o SIG da FLONA. Foram identificados quatro geoambientes principais: Platôs Dissecados com Mata sobre Latossolos e Argissolos; Encostas e Rampas com Mata sobre Argissolos; Planícies Aluviais Eutróficas com Neossolos Flúvicos e Gleissolos; e Planícies Aluviais Distróficas com Gleissolos. Os aluviões holocênicos na área sob influência do rio Purus são ricos em nutrientes (eutróficos), com influência de sedimentos subandinos. Em contraste, a maior parte da FLONA possui solos extremamente ácidos e pobres em nutrientes (distróficos), formados a partir do intemperismo de sedimentos da Formação Solimões. O manejo dessas áreas deve visar ao incremento do aporte de biomassa na superfície dos solos, aumentando a eficiência da ciclagem de nutrientes pela vegetação, já que a reserva química natural é extremamente baixa.

Poblaciones de babillas (caiman crocodilus) y caimán negro (melanosuchus niger) en la reserva biológica del abufari, amazonas, Brasil

En el presente estudio fueran investigadas la densidad, tallas de la población y la utilización de los ambientes por Melanosuchus niger y Caiman crocodilus en la Reserva Biológica de Abufari, situada en el bajo río Purus. El estudio fue desarrollado en septiembre de los años 2001 y 2003. Fueran observados 1.217 caimanes, donde M. niger y C. crocodilus corresponden al 76% y al 24%, respectivamente. Durante el estudio fueran investigados 33,3 km de margen del rio Purus y 28,3 km de margen en los lagos e tributarios. La abundancia relativa de caimanes observada en el año 2001 (24 caimanes /km) fueran mucho mayores que las del año 2003 (17 caimanes/km), pero las diferencias no fueran estadísticamente significativas. Los datos muestran que tanto la población de caimán negro como la populación de los babas están compuestas por individuos de tallas grandes. Muchos M. niger y C. crocodilus observados estaban por encima de la menor talla reproductiva 30,85% y 27,73%, respectivamente. Las distribuciones de caimanes en los ambientes fueran basadas en dados de distribución y abundancia que mostraron tres agrupamientos, siendo uno de estos predominantemente ocupado por caimán negro (M. niger), otro tanto por caimán negro como por baba (C. crocodilus) e un tercero donde predominaban el baba (C. crocodilus). La interacción hombre-caimán medida por el índice de disturbación, que fue mayor en los ríos y áreas próximas a las comunidades ribereñas do que nos canales de pequeños riachos, playas y áreas remotas. Investigaciones posteriores son necesarias, porque permitirán de una forma más precisa una mejor evaluación de las proporciones sexuales y permitirán también identificar los ambientes importantes para la reproducción de estas dos especies de caimanes. Además, es importante incluir las comunidades ribereñas en el proceso de investigación, conservación y uso sostenible del recurso

Reproductive and population parameters of discus fish Symphysodon aequifasciatus Pellegrin, 1904 (Perciformes: Cichlidae) from Piagaçu-Purus Sustainable Development Reserve (RDS-PP), lower Purus River, Amazonas, Brazil

The ornamental discus fish Symphysodon aequifasciatus Pellegrin, 1904, is a popular endemic cichlid species from the Amazon basin, however scientific information concerning biology and ecology in its natural habitat is scarce despite its importance on the international aquarium trade. In this study we evaluated reproductive parameters of S. aequifasciatus in natural habitat in Piagaçu-Purus Sustainable Development Reserve (RDS-PP), lower Purus River, Brazilian Amazon. Males are more frequent in the larger size classes and this might be related to the complex breeding behavior known for S. aequifasciatus. Values of L50 for both sexes corresponded to more than 60% of the maximum attained length which may indicate that energy allocation for somatic growth takes longer in S. aequifasciatus than in other species. Average fecundity for female discus was 1490, ranging from 950 to 1892 oocytes and its correlations with standard length and total weight were very low, probably due to the highly compressed discus' body shape. Egg size distribution showed four types of patterns, indicating one to four modes besides the reserve oocytes group. Our results indicate that S. aequifasciatus shows total spawning, in the beginning of flooding period, with the peculiar capacity of releasing multiple egg batches as a strategy that potentially enhances reproductive success.

First lizard remains (Teiidae) from the Miocene of Brazil (Solimões Formation)

The South American Teiidae fossil record is restricted to the Cenozoic, and the most conspicuous remains were found in Early to Late Miocene of Argentina and Middle Miocene of Colombia and Peru, all represented by Tupinambinae lizards. Here, we describe a right fragmentary dentary and one dorsal vertebra collected in the Solimoes Formation at the Talisma locality, situated on the Purus River, in the southwestern Brazilian Amazonia (Late Miocene). The material is tentatively conferred to the extinct genus Paradracaena. It represents the first record of lizards for the Neogene southwestern Brazilian Amazonia.

Presence of the Genus Eunectes (Serpentes, Boidae) in the Neogene of Southwestern Amazonia, Brazil

The extant genus Eunectes was first reported for the Middle Miocene of Colombia, represented by the extinct species Eunectes stirtoni. Here, we describe vertebral remains referable to this genus collected in the Neogene Solimoes Formation at the Talisma locality, situated on the right-hand bank upstream of the Purus River, in the South of Amazonas State, Brazil. The material consists of isolated mid- and posterior trunk vertebrae characterized by the following combination of features that distinguishes the genus from other Neotropical boids: large size, slightly depressed neural arch, relatively low neural spine, robust and moderately thick zygosphene, with a prominent median tubercle, paracotylar foramen irregularly present, and a strong lateroventral projection of the paradiapophyses on the posterior trunk vertebrae. The presence of Eunectes in the Solimoes Formation represents the first fossil record of snakes from the southwestern Brazilian Amazonia and supports the origin of this genus in the Miocene or before.

Novel sources of witches’ broom resistance (causal agent Moniliophthora perniciosa) from natural populations of Theobroma cacao from the Brazilian Amazon

Witches' broom is a severe disease of Theobroma cacao L. (cacao), caused by the basidio- mycete Moniliophthora perniciosa. The use of resistant cultivars is the ultimate method of con- trol, but there are limited sources of resistance. Further, resistance from the most widely used source ('Scavina 6') has been overcome after a few years of deployment. New sources of resistance have been intensively searched for in the Amazon basin. Here, we evaluated for witches' broom resistance, cacao accessions from various natural cacao populations originally collected in the Brazilian Amazon. Resis- tance of 43 families was evaluated under nursery and/ or field conditions by artificial or natural infection, respectively, based on disease incidence. Screening for resistance by artificial inoculation under nursery conditions appeared to be efficient in identifying these novel resistance sources, confirmed by natural field evaluation over a nine-year period. The increase in natural field infection of 'Scavina 6' was clearly demonstrated. Among the evaluated families with the least witches' broom incidence, there were accessions originally collected from distinct river basins, includ- ing the Jamari river ('CAB 0371'; 'CAB 0388'; 'CAB 0392'; and 'CAB 0410'); Acre ('CAB 0169'); Javari ('CAB 0352'); Solimoes ('CAB 0270'); and from the Purus river basin, the two most outstanding resistant accessions, 'CAB 0208' and 'CAB 0214'. The large genetic diversity found in cacao popula- tions occurring at river basins from Acre and Amazonas states, Brazil, increased the chance that the selected resistant accessions would be genetically more dissimilar, and represent distinct sources of resistance to M. perniciosa from 'Scavina 6'.

Aspectos ecológicos e epidemiológicos de acidentes ofídicos em comunidades ribeirinhas do baixo rio Purus, Amazonas, Brasil

Acidentes ofídicos foram registrados em dez comunidades ribeirinhas do baixo rio Purus através de entrevista às vítimas. Os ribeirinhos responderam perguntas sobre a percepção ambiental da ecologia das serpentes envolvidas nos acidentes. O tamanho das serpentes e a altura da mordida no corpo foram estimados com fita métrica. A correspondência entre os nomes locais e científicos das serpentes foi levantada utilizando descrições e imagens das espécies. Para outras 17 comunidades dados adicionais do número de famílias com vítimas de acidentes ofídicos foram avaliados através do diagnóstico sócio-ambiental da Reserva de Desenvolvimento Sustentável Piagaçu-Purus. Foram entrevistados 18 ribeirinhos e registrados 28 acidentes ofídicos em cinco comunidades. O número de vítimas por comunidade não teve relação com o tamanho da população. O número de famílias com vítimas foi maior em comunidades maiores (r²= 0,444; p= 0,003). Aproximadamente 88% das mordidas foram nos membros inferiores. Não houve relação do tamanho estimado da serpente com a altura da mordida. A maioria dos acidentes ocorreu de dia (82,14%) e no período de cheia (64,28%) na época de exploração da castanha-da-Amazônia e da madeira pelos ribeirinhos, atividades que despendem maior tempo na floresta. Um único caso de morte por acidente ofídico foi registrado. A serpente Bothrops atrox foi à espécie mais relacionada com acidentes na região. O reconhecimento das serpentes pelos ribeirinhos revelou várias sinonímias, com 20 nomes locais atribuídos a 33 espécies. Na percepção dos ribeirinhos as serpentes B. atrox e Lachesis muta foram às espécies mais temidas e diferem no comportamento de ataque.

Ocorrência da Mansonella ozzardi (Nematoda, Onchocercidae) em comunidades ribeirinhas do rio Purus, Município de Boca do Acre, Amazonas, Brasil

The study aimed to estimate the prevalence of Mansonella ozzardi and calculate the parasitic infection rate in simuliid blackflies. The research was conducted in communities on the Purus River, Boca do Acre municipality, Amazonas State, Brazil. Prevalence was measured using the thick smear method. Captured blackflies were dissected to verify the parasitic infection rate. M. ozzardi prevalence was 27.30% (77/282). The study showed higher prevalence in men (31.97%) than women (22.22%), farmers (48.99%), and individuals in the 38-47 (60.00%), 48-57 (66.66%), and 58-67-year age brackets (75.00%). Microfilaremia was higher in individuals 58 to 67 years of age (average= 58.41 mf/40 microl), men (41.44 mf/40 microl), and farmers (49.94 mf/40 microl). Only the simuliid Cerqueirellum amazonicum was found infected with a parasitic infection rate of 0.98%.

Etnografia e manejo de recursos naturais pelos índios Deni, Amazonas, Brasil

São raros os estudos envolvendo o uso múltiplo de recursos naturais por populações amazônicas. Este trabalho apresenta um panorama de como os índios Deni, habitantes da região de interflúvio entre dois dos maiores afluentes de água branca da bacia amazônica, os rios Juruá e Purus, utilizam dos recursos disponíveis em seu território. Os Deni são, atualmente, índios que vivem da exploração de recursos da terra firme e de regiões alagadas. São um misto de horticultores e caçadores/coletores, que utilizam toda a sua área para a obtenção de recursos para subsistência. Como regra, deslocam periodicamente seus assentamentos, evitando o esgotamento local de recursos, e provocando a modificação local do ambiente. Esta alteração aumenta temporariamente a disponibilidade de alimento. Áreas com aldeias, pomares e roçados abandonados, por sua vez, tornam-se locais onde se concentram inúmeros recursos da flora e da fauna, posteriormente explorados. O impacto provocado por este sistema é aparentemente mínimo. Os Deni estão contextualizados na periferia de um sistema capitalista, onde a única fonte de renda para adquirir bens que são hoje considerados pelos índios como indispensáveis para sua sobrevivência são os recursos naturais. Estes são e continuarão sendo explorados de maneira a produzir um excedente a ser comercializado para a obtenção de uma série de produtos industrializados, independentemente das opiniões externas. É sobre este patamar que devemos avaliar a sustentabilidade do atual manejo da área.

Selección de locales de nidificación y sobrevivencia de los nidos de las tortugas podocnemis del bajo rio purus, amazonas, Brasil.

Este estudio fue realizado en las playas Del rio Abufari que hace parte de la Reserva Biológica de Abufari, situada en El bajo rio Purus, Amazonas, Brasil. El estudio se condujo en los períodos secos (agosto/diciembre) desde 1998 hasta 2004. Fue analizada la selección de microhábitat de desove de Podocnemis expansa, P. sextuberculata y P. unifilis. Fue verificado que las tres especies estudiadas poseen patrones distintos en la escogencia del local de postura de su nido. P. expansa desova en grandes aglomeraciones y en las porciones más altas de la playa (encima de 400 cm), P. sextuberculata también desova en locales con altura elevada, sin embargo, los nidos están dispersos a la largo de la playa. No fue observado un patrón de selección de locales de desove para P. unifilis. La principal causa de pérdida de nidos de P. expansa es la remoción de nidadas de esta especie hecha por las hembras que ingresan a la playa a desovar al final del período de nidificación. En los casos de P. sextuberculata e P. unifilis las causas de pérdida de nidos en la playa de Abufari se relacionan con depredación causada principalmente por el lagarto Tupinambis sp. y por el ave Coragips atratus, y la inundación ocasionada por las aguas del rio Purus, dado que los nidos de la playa se encontraban por debajo de 100 cm de altura en relación al nivel, lo que les daba una mayor probabilidad de ser anegados

Primer registro de amblyodus taurus westwood, 1878 (scarabaeidae: dynastinae: phileurini) en Brasil.

The scarab beetle Amblyodus taurusWestwood, 1878 (Scarabaeidae: Dynastinae: Phileurini) is record for the first time in Brazil (Brazilian Amazon), based upon several specimens collected in terra firme primary rainforest, in the interfluvial region between the Juruá river and the Purus river, Amazonas State.

Influência da precipitação na qualidade da água do Rio Purus

Os impactos da precipitação na qualidade da água ao longo do rio Purus, localizado no estado do Amazonas, foi investigado por meio de dados de precipitação, estimada por satélites, e informações sobre a temperatura da água, condutividade, pH, turbidez, oxigênio dissolvido e sólidos suspensos totais, adquiridas em quatro diferentes áreas ao longo do rio. Os resultados mostraram correlação negativa entre precipitação e turbidez e positiva entre precipitação e temperatura, condutividade, oxigênio dissolvido, sólidos suspensos totais e pH. O uso do solo, juntamente com o regime de precipitação, parecem ser os fatores principais que determinam a qualidade da água nos pontos de amostragem.

Mansonellosis at Medium Purus River (Brazilian Amazon)

Mansonella ozzardi is a filarial autochthonous parasite of the American continent that is frequently found infecting human beings in the Brazilian Amazon. The human infection by M. ozzardi is still seen as non pathogenic despite the variety of symptoms related to it such as fever, articular pain, headache, lymphadenopathy, eosinophily and pruritic skins eruptions. During an expedition in the Acre State, we were able to visit the Kamikuã, an Indian village located along the Purus river, close to the city of Boca do Acre (Amazonas State). The inhabitants had been diagnosed as harboring dog´s worms (Dirofilaria immitis) but our blood samples collections from some individuals evidenced M. ozzardi infections. In fact, human populations from endemic areas are always complaining about symptoms of M. ozzardi infection and remain living together with high parasitic loads in the expectation of correct diagnostic and treatment. Studies on mansonellosis chemotherapy and control should be carried out in order to add knowledge about the infection and to provide hope and answers for those who live in endemic areas.

Mansonelose no Médio Rio Purus (Amazônia Brasileira)

Mansonella ozzardi is a filarial autochthonous parasite of the American continent that is frequently found infecting human beings in the Brazilian Amazon. The human infection by M. ozzardi is still seen as non pathogenic despite the variety of symptoms related to it such as fever, articular pain, headache, lymphadenopathy, eosinophily and pruritic skins eruptions. During an expedition in the Acre State, we were able to visit the Kamikua, an Indian village located along the Purus river, close to the city of Boca do Acre (Amazonas State). The inhabitants had been diagnosed as harboring dog´s worms (Dirofilaria immitis) but our blood samples collections from some individuals evidenced M. ozzardi infections. In fact, human populations from endemic areas are always complaining about symptoms of M. ozzardi infection and remain living together with high parasitic loads in the expectation of correct diagnostic and treatment. Studies on mansonellosis chemotherapy and control should be carried out in order to add knowledge about the infection and to provide hope and answers for those who live in endemic areas.

Fish, upper Purus River, state of Acre, Brazil

The ichthyofauna of the headwaters of the main tributaries of the mighty Solimões/Amazonas River has been little studied. Considering the importance of those environments for the overall fish diversity in that river system, we surveyed the composition of the fish fauna of the upper portion of Purus River and two of its tributaries (Caeté and Macapá rivers), state of Acre, Brazil. The collections were done in November 2004, using a seine net and a set of gillnets of different mesh sizes. A total of 735 specimens belonging to 86 species and 28 families were collected. Eight species, Creagrutus occidaneus, Phenacogaster pectinatus, Prionobrama filigera, Moenkhausia cf. lepidura, Leptagoniates pi (Characidade), Henonemus punctatus (Trichomycteridae), Toracocharax stellatus (Gateropelecidae), and Eigenmannia macrops (Sternopygidae) composed nearly half of the specimens collected. This survey adds 48 new records to the ichthyofauna of Purus River and elevates to 243 the number of known fish species in that river, but a greater sampling effort is necessary to produce a reasonably complete picture of the fish diversity in the basin.

Avaliação do desembarque pesqueiro efetuado em Manacapuru, Amazonas, Brasil

A atividade comercial pesqueira na Amazônia Central é predominantemente direcionada para Manaus, porém o perfil das atividades pesqueiras efetuadas nos demais centros também é fundamental para o planejamento do setor. Neste contexto, o presente trabalho visa caracterizar o perfil da produção pesqueira que abastece a cidade de Manacapuru, um dos principais centros urbanos da Amazônia Central. Os desembarques ocorreram a partir de canoas a remo, canoas motorizadas, barcos de pesca e recreios. A média mensal de pescado desembarcado foi de 175,36 ± 39,50 t em 2001 e de 172,13 ± 18,88 t em 2002, não apresentando diferença significativa entre anos (P>0,05). Dos 35 nomes específicos comuns registrados, observa-se que curimatã (Prochilodus nigricans), jaraquis (Semaprochilodus spp.), cubiu (Anodus spp.), mapará (Hypophthalmus spp.), e tambaqui (Colossoma macropomum) foram os itens mais importantes nos dois anos, e piramutaba (Brachyplatystoma vaillantii) em 2002. Sete sub-regiões foram visitadas pela frota pesqueira, destacando-se Baixo-Solimões e o rio Purus.

Soroprevalência de tripanossomíase americana em adultos de uma área da Amazônia ocidental Brasileira

From January to March 2001 a seroepidemiological survey for American trypanosomiasis (Chagas disease) was carried out among urban and rural human populations in areas of the Upper Purus basin, in the western Brazilian Amazon region, using serial testing with three different serological techniques. The sample was composed of 1,055 individuals: 844 from urban and 211 from rural areas. Autochthonous infection was identified in nine individuals aged 16 to 72 years: five from urban and four from rural areas. The estimated prevalences of Chagas infection for the urban and rural areas were 0.6% (95% CI: 0.2-1.4) and 1.9% (95% CI: 0.6-4.5) respectively. An apparent clustering trend was noted: seven were born along the Purus river: three lived at the same locality and two of them in the same dwelling.

Epidemiological studies of Mansonella ozzardi (Nematoda, Onchocercidae) in indigenous communities of Pauini municipality, Amazonas, Brazil

The Mansonella ozzardi has a widespread distribution among the indigenous and riverine communities of Amazonas, Brazil. We estimated the prevalence of Mansonella ozzardi in indigenous communities of the Pauini municipality, Amazonas state, Brazil and the rate of parasitic infection in vectors. We collected thick blood smears from individuals from six Apurinã indigenous communities along the Purus River and its tributaries. Collections of simuliids were made and dissected, and the larval instars of M. ozzardi identified. The overall prevalence of M. ozzardi was 28.40%, with the highest incidence among males and agricultural workers. Among age groups, children 2-9 years of age had the lowest incidence, while individuals older than 58 exhibited the highest rates of infection. We found infected simuliids in three communities, with Parasitic Infection Rates (PIR) of 0.34-6.58%. The prevalence of M. ozzardi among the Apurinã people is high, possibly related to the diary activities of the riparian people, where a high abundance of the vectors exists.