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Sample records for astyanax scabripinnis jenyns

  1. Occurrence of intersexuality in " Lambaris" , Astyanax scabripinnis (Jenyns, 1842, small characids from the Brazilian streams

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    Maria de Fátima Pereira de Sá

    2008-04-01

    Full Text Available During studies carried out with a small characid (Astyanax scabripinnis, from the Brazilian streams located in Cerrado biome, some gonads of fishes exhibited sparse oocytes in perinucleolar stage embedded in normally developing testicular tissues. Another pattern of gonad intersex with vitellogenic oocytes and mature lobules was observed in the gonads of fishes collected from a reservoir supplied by the Atlantic Forest stream. These gonads in different stages of maturation were examined histologically. The results revealed the patterns occurring in fishes of the same species, from four different populations.Durante estudos efetuados com pequenos caracídeos (Astyanax scabripinnis de riachos do Cerrado brasileiro, localizados nos Estados de Minas Gerais e de São Paulo, foram encontrados alguns peixes com gônadas exibindo oócitos em estágio perinucleolar dispersos, embebidos em tecidos testiculares em desenvolvimento. Em exemplares da mesma espécie, provenientes de um riacho situado na Mata Atlântica do Estado de São Paulo, outro padrão de gônadas intersexuadas foi registrado, mostrando oócitos vitelogênicos e lóbulos maduros presentes na mesma gônada. As gônadas em diferentes estágios de maturação foram submetidas a análises histológicas. Os resultados obtidos mostram os padrões morfológicos e as freqüências de ocorrência dos intersexos encontrados em peixes do " complexo" A. scabripinnis provenientes de quatro diferentes populações. São discutidas as prováveis causas ambientais responsáveis por estas alterações.

  2. Comparative cytogenetic and morphological analysis of Astyanax scabripinnis paranae (Pisces, Characidae, Tetragonopterinae

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    Maistro Edson Luis

    1998-01-01

    Full Text Available Cytogenetic and morphological studies were carried out on nine local populations of Astyanax scabripinnis paranae. All populations exhibited 2n = 50 chromosomes as well as conspicuous differences involving karyotype morphology, number and position of nucleolar organizer regions (NORs and amount and/or locations of constitutive heterochromatin blocks. A quantitative study of the cytogenetic data showed that eight populations possessed different karyotypes. Morphological analyses based on nine measurements and two meristic parameters were effective in establishing clear identification of five populations. Comparative analysis of cytogenetic and morphological traits suggests that chromosomal changes have occurred at a more rapid rate than morphological differentiation. Despite the close morphological similarity found among some populations, chromosomal differentiation was identified in all of them, even in those presenting only small morphological differences.

  3. Identification and chromosome mapping of repetitive elements in the Astyanax scabripinnis (Teleostei: Characidae) species complex.

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    Barbosa, Patrícia; de Oliveira, Luiz Antonio; Pucci, Marcela Baer; Santos, Mateus Henrique; Moreira-Filho, Orlando; Vicari, Marcelo Ricardo; Nogaroto, Viviane; de Almeida, Mara Cristina; Artoni, Roberto Ferreira

    2015-02-01

    Most part of the eukaryotic genome is composed of repeated sequences or multiple copies of DNA, which were considered as "junk DNA", and may be associated to the heterochromatin. In this study, three populations of Astyanax aff. scabripinnis from Brazilian rivers of Guaratinguetá and Pindamonhangaba (São Paulo) and a population from Maringá (Paraná) were analyzed concerning the localization of the nucleolar organizer regions (Ag-NORs), the As51 satellite DNA, the 18S ribosomal DNA (rDNA), and the 5S rDNA. Repeated sequences were also isolated and identified by the Cot - 1 method, which indicated similarity (90%) with the LINE UnaL2 retrotransposon. The fluorescence in situ hybridization (FISH) showed the retrotransposon dispersed and more concentrated markers in centromeric and telomeric chromosomal regions. These sequences were co-localized and interspaced with 18S and 5S rDNA and As51, confirmed by fiber-FISH essay. The B chromosome found in these populations pointed to a conspicuous hybridization with LINE probe, which is also co-located in As51 sequences. The NORs were active at unique sites of a homologous pair in the three populations. There were no evidences that transposable elements and repetitive DNA had influence in the transcriptional regulation of ribosomal genes in our analyses.

  4. Ocorrência e ecologia trófica de quatro espécies de Astyanax (Characidae em diferentes rios da bacia do rio Tibagi, Paraná, Brasil Occurrence and trophic ecology of four species of Astyanax (Characidae in different rivers of the Tibagi River Basin, Paraná, Brazil

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    Sirlei Terezinha Bennemann

    2005-09-01

    Full Text Available Na bacia do rio Tibagi, trechos dos rios Fortaleza, Iapó e Tibagi foram amostrados mensalmente, de maio de 2001 a abril de 2002, com tarrafas e redes de espera de diferentes malhagens. Foram capturados indivíduos de quatro espécies de Astyanax. Para conhecer como essas espécies utilizam o hábitat desses rios, foi calculada a constância, e as freqüências em número de exemplares foram comparadas pela análise de similaridade Bray-Curtis. A composição percentual dos alimentos consumidos foi ordenada usando-se a Análise de Componentes Principais (ACP. As proporções dos recursos alimentares foram avaliadas e classificadas quanto à natureza (animal ou material vegetal e origem (alóctone e autóctone. A constância e a baixa similaridade na abundância revelaram que as espécies têm preferências quanto ao porte do rio ou por determinado hábitat. Astyanax altiparanae Garutti & Britski, 2000 e A. fasciatus (Cuvier, 1819 ocorreram nos de maior porte, mas foram constantes somente no rio Tibagi. Astyanax eigenmanniorum (Cope, 1894 ocorreu em todos os rios, mas prefere hábitats próximos às desembocaduras de afluentes de grandes rios. Astyanax scabripinnis (Jenyns, 1842 esteve restrita ao Fortaleza, o rio de menor porte, subafluente do rio Tibagi. O número de itens alimentares consumidos variou de 11 a 23. Entre os alimentos principais, três itens foram comuns para as quatro espécies: restos de plantas (folhas e sementes de plantas terrestres, restos de insetos (de diferentes origens e não identificados e plantas aquáticas. Os vegetais e os insetos foram os principais alimentos para todas as espécies. A maior distinção na composição da dieta foi constatada para A. eigenmaniorum, devido à sua habilidade em explorar as plantas aquáticas, presentes em abundância, consumidas junto com carvão/sedimento, que estavam nas margens rochosas do rio Iapó. A similaridade quanto à origem e ao tipo de alimento consumido pelas quatro esp

  5. Plasticity in the diet of Astyanax taeniatus in a coastal stream from south-east Brazil.

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    Manna, L R; Rezende, C F; Mazzoni, R

    2012-11-01

    In this work we aimed to characterise the diet of Astyanax taeniatus (Jenyns 1842) (Characiformes, Characidae) along the Mato Grosso stream and we hypothesised that the diet of this species would vary according to spatial, seasonal and ontogenetic differences. Specimens were collected every second month at three sites with different physical attributes. The feeding habits of 651 specimens were analysed using the Alimentary Index (IA(i)). Analysis of the diet showed an effect of spatial, temporal and ontogenetic factors. Vegetal allochthonous items were more important in the diet of Astyanax taeniatus in upstream sites while animal autochthonous items were more important downstream. Ontogenetic differences in the diet were significant only in upstream sites, where adults consumed a greater amount of vegetal matter than juveniles. These results reinforce the idea that Astyanax species are opportunistic and show trophic plasticity.

  6. Restriction fragment length polymorphisms of mitochondrial DNA among five freshwater fish species of the genus Astyanax (Pisces, Characidae

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    Cinthia Bachir Moysés

    2002-01-01

    Full Text Available Restriction fragment length polymorphism (RFLP analysis of mitochondrial DNA (mtDNA was employed to characterize species and populations of Astyanax, a Neotropical freshwater fish genus. Samples of five species, A. altiparanae, A. fasciatus, A. lacustris, A. scabripinnis paranae and A. schubarti, from the Upper Paraná and São Francisco river basins were analyzed. Two out of the ten restriction enzymes employed generated species-specific mtDNA patterns for each of the five species. MtDNA exhibited considerable polymorphism within and among populations. All populations sampled showed relatively high values of haplotype diversity. Geographically localized haplotypes were detected for A. altiparanae and A. fasciatus from the Upper Paraná and São Francisco basins. The relationships between populations are discussed.

  7. Highlighting Astyanax Species Diversity through DNA Barcoding

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    Oliveira, Carlos Alexandre Miranda; de Melo, Filipe Augusto Gonçalves; Bertaco, Vinicius de Araújo; de Astarloa, Juan M. Díaz; Rosso, Juan J.; Foresti, Fausto; Oliveira, Claudio

    2016-01-01

    DNA barcoding has been used extensively to solve taxonomic questions and identify new species. Neotropical fishes are found in a wide variety of shapes and sizes, with a large number of species yet to be described, many of which are very difficult to identify. Characidae is the most species-rich family of the Characiformes, and many of its genera are affected by taxonomic uncertainties, including the widely-distributed, species-rich genus Astyanax. In this study, we present an extensive analysis of Astyanax covering almost its entire area of occurrence, based on DNA barcoding. The use of different approaches (ABGD, GMYC and BIN) to the clustering of the sequences revealed ample consistency in the results obtained by the initial cutoff value of 2% divergence for putative species in the Neighbor-Joining analysis using the Kimura-2-parameter model. The results indicate the existence of five Astyanax lineages. Some groups, such as that composed by the trans-Andean forms, are mostly composed of well-defined species, and in others a number of nominal species are clustered together, hampering the delimitation of species, which in many cases proved impossible. The results confirm the extreme complexity of the systematics of the genus Astyanax and show that DNA barcoding can be an useful tool to address these complexes questions. PMID:27992537

  8. Distinct classical and molecular cytogenetics of Astyanax marionae ...

    Indian Academy of Sciences (India)

    This study aimed to analyse the karyotype of different populations of Astyanax fasciatus (Corumbataí River basin) using Giemsa staining, C-band technique, and fluorescence in situ hybridization for the H3 histone and 5S rRNA genes, in addition we describe for the first time the chromosomal organization of H3 histone and ...

  9. Characteristics of infection of Diplectanum sp. (Monogenea: Monopisthocolytea: Diplectanidae in Cynoscion analis Jenyns (Pisces: teleostei: Scianidae

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    José Iannacone

    2014-06-01

    Full Text Available 120 Cynoscion analis Jenyns were collected from Chorrillos fishmarket, Lima, Perú, between January and February 2000 and necropsied to study ectoparasite monogenean Diplectanum sp. from branchial filaments. This parasite was considered a core specie, because it parasites 2/3 hosts examined. Of the fishes collected 80 were female and 40 male. Females and males showed a standard length between 16,4-27,0 cm (mean = 21,08 ± 2,24 and 16,5-26,3 cm (mean = 20,47 ± 2,06, respectively. The prevalence of infection of Diplectanurn was 72,5%, mean intensity and abundance were 3,16 ± 2,84 and 2,29 ± 2,80 respectively. This monogenean showed an overclispersal spatial distribution (2,55 at level of fish hosts. We observed a correlation between mean intensity of infestation and standard length of C. analis. Males (4,14 ± 3,75 showed a higher mean intensity than females (2,67 ± 2,14. A high prevalence, intensity and abundance of Diplectanum to 11 gill was found. However, we did not find neither preference when we separated each gill in three parts (fore, middle and hind respectively. Finally, we compared our results of population assemblages of other ectoparasite monogeneans in marine fishes. Diplectanurn sp. is a new record to C. analis and to Peru.

  10. Parallel speciation in Astyanax cave fish (Teleostei) in Northern Mexico.

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    Strecker, Ulrike; Hausdorf, Bernhard; Wilkens, Horst

    2012-01-01

    We investigated differentiation processes in the Neotropical fish Astyanax that represents a model system for examining adaptation to caves, including regressive evolution. In particular, we analyzed microsatellite and mitochondrial data of seven cave and seven surface populations from Mexico to test whether the evolution of the cave fish represents a case of parallel evolution. Our data revealed that Astyanax invaded northern Mexico across the Trans-Mexican Volcanic Belt at least three times and that populations of all three invasions adapted to subterranean habitats. Significant differentiation was found between the cave and surface populations. We did not observe gene flow between the strongly eye and pigment reduced old cave populations (Sabinos, Tinaja, Pachon) and the surface fish, even when syntopically occurring like in Yerbaniz cave. Little gene flow, if any, was found between cave populations, which are variable in eye and pigmentation (Micos, Chica, Caballo Moro caves), and surface fish. This suggests that the variability is due to their more recent origin rather than to hybridization. Finally, admixture of the young Chica cave fish population with nuclear markers from older cave fish demonstrates that gene flow between populations that independently colonized caves occurs. Thus, all criteria of parallel speciation are fulfilled. Moreover, the microsatellite data provide evidence that two co-occurring groups with small sunken eyes and externally visible eyes, respectively, differentiated within the partly lightened Caballo Moro karst window cave and might represent an example for incipient sympatric speciation. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Comparative cytogenetics in Astyanax (Characiformes: Characidae with focus on the cytotaxonomy of the group

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    Renata Cristina Claudino de Oliveira Tenório

    Full Text Available Astyanax is a diverse group of Neotropical fishes, whose different forms occupy different environments. This great diversity is also reflected on cytogenetic aspects and molecular markers, which have repeatedly been demonstrated by cytogenetic studies. In order to characterize the karyotype of species of this genus, six species were studied: Astyanax altiparanae, A.argyrimarginatus, A. elachylepis, A. xavante, and two new species provisionally called Astyanax sp. and A. aff. bimaculatus. A detailed cytogenetic study based on conventional staining with Giemsa, AgNORs, C-banding, base-specific fluorochromes, and FISH using ribosomal genes 18S and 5S was conducted, aiming to understand some of the chromosomal mechanisms associated with the high diversification that characterizes this group and culminated with the establishment of these species. The results showed 2n = 50 chromosomes for five species and a karyotype with 52 chromosomes in Astyanax sp. Small variations in the macrostructure of the karyotypes were identified, which were quite relevant when analyzed by classical banding, fluorochromes, and FISH methods. These differences among Astyanax spp. (2n = 50 are largely due to changes in the amount and types of heterochromatic blocks. Astyanax sp (2n = 52, in addition to variations due to heterochromatic blocks, has its origin possibly by events of centric fission in a pair of chromosomes followed by minor rearrangements.These results show an interesting karyotypic diversity in Astyanax and indicate the need of a review of the group referred as A. aff. bimaculatus and the description of Astyanax sp., including the possibility of inclusion of this unit in another genus.

  12. Next generation phylogeography of cave and surface Astyanax mexicanus.

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    Coghill, Lyndon M; Darrin Hulsey, C; Chaves-Campos, Johel; García de Leon, Francisco J; Johnson, Steven G

    2014-10-01

    The loss of traits is a commonly observed evolutionary pattern in cave organisms, but due to extensive morphological convergence, inferring relationships between cave and surface populations can be difficult. For instance, Astyanax mexicanus (the blind Mexican cavefish) is thought to have repeatedly lost its eyes following colonization of cave environments, but the number of evolutionarily independent invasions of this species into caves remains unclear. Because of these repeated losses, it has become a model organism for studying the genetic basis of phenotypic trait loss. Here we reconstruct a high-resolution phylogeography for A. mexicanus inferred from both mitochondrial DNA and several thousand single nucleotide polymorphisms. We provide novel insight into the origin of cave populations from the Sabinos and Río Subterráneo caves and present evidence that the Sabinos cave population is part of a unique cave lineage unrelated to other A. mexicanus cave populations. Our results indicate A. mexicanus cave populations have at least four independent origins. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Spatial and temporal events in tooth development of Astyanax mexicanus.

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    Atukorala, Atukorallaya Devi Sewvandini; Franz-Odendaal, Tamara Anne

    2014-11-01

    The Mexican tetra (Astyanax mexicanus), a freshwater teleost fish, is an excellent vertebrate model organism to study tooth development, specifically the spatiotemporal events related to the development of the oral and pharyngeal dentitions. In contrast to the coordinated early tooth development in the premaxilla and mandible, the maxillary teeth develop much later in life at 60 dpf. By analysing a growth series of bone and cartilage stained tetra and histological sectioning of the tooth bearing bones, we track the developmental events of tooth development over ontogeny of this animal. Whole mount in situ hybridisation with bone morphogenetic proteins and their inhibitor Noggin was conducted to track the late tooth development events. Our data show that the first generation teeth are small and unicuspid irrespective of their location. Oral jaw teeth become multicuspid and large over ontogeny while the pharyngeal dentition remains unicuspid and disorganised. Tooth eruption occurs late in the maxillary bone. The distinct expression pattern of the BMP antagonist, Noggin, suggests that Noggin plays an inhibitory role by preventing early tooth development in the maxillary bone. These data further support and highlight the use of the Mexican tetra in understanding the spatio-temporal differences in tooth development in vertebrate jaws. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. A new species of Astyanax (Characiformes: Characidae) from Dolina Água Milagrosa, Rio Paraguai basin, Mato Grosso, Brazil.

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    da Graça, W J; Oliveira, C A M; Lima, F C T; da Silva, H P; Fernandes, I M

    2017-10-01

    A new species of Astyanax is described from the upper Rio Paraguai basin, Mato Grosso State, Brazil. The new species can be distinguished from congeners by having the body intensely yellowish in life (v. silvery, reddish or lightly yellow) and by morphometric and meristics traits. Astyanax dolinae n. sp. cannot be assigned to any of the Astyanax species complex currently recognized for the genus. It is only known from the Dolina Água Milagrosa, a karstic sinkhole lake, entirely fed by groundwater, surrounded by Cerrado, the savannah-like vegetation of central South America. © 2017 The Fisheries Society of the British Isles.

  15. Genome editing using TALENs in blind Mexican Cavefish, Astyanax mexicanus.

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    Li Ma

    Full Text Available Astyanax mexicanus, a teleost fish that exists in a river-dwelling surface form and multiple cave-dwelling forms, is an excellent system for studying the genetic basis of evolution. Cavefish populations, which independently evolved from surface fish ancestors multiple times, have evolved a number of morphological and behavioral traits. Quantitative trait loci (QTL analyses have been performed to identify the genetic basis of many of these traits. These studies, combined with recent sequencing of the genome, provide a unique opportunity to identify candidate genes for these cave-specific traits. However, tools to test the requirement of these genes must be established to evaluate the role of candidate genes in generating cave-specific traits. To address this need, we designed transcription activator-like effector nucleases (TALENs to target two genes that contain coding changes in cavefish relative to surface fish and map to the same location as QTL for pigmentation, oculocutaneous albinism 2 (oca2 and melanocortin 1 receptor (mc1r. We found that surface fish genes can be mutated using this method. TALEN-induced mutations in oca2 result in mosaic loss of melanin pigmentation visible as albino patches in F0 founder fish, suggesting biallelic gene mutations in F0s and allowing us to evaluate the role of this gene in pigmentation. The pigment cells in the albino patches can produce melanin upon treatment with L-DOPA, behaving similarly to pigment cells in albino cavefish and providing additional evidence that oca2 is the gene within the QTL responsible for albinism in cavefish. This technology has the potential to introduce a powerful tool for studying the role of candidate genes responsible for the evolution of cavefish traits.

  16. Bases biológicas para el cultivo del puye Galaxias maculatus (Jenyns, 1842: una revisión

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    Rolando Vega

    2013-07-01

    Full Text Available Galaxias maculatus (Jenyns, 1842 es un pez gourmet de importancia comercial cuyas pesquerías están sobre-explotadas, siendo esencial el estudio de su biología para desarrollar su tecnología de cultivo (galaxicultura, que se encuentra en etapa piloto. Los objetivos de éste trabajo son: 1 entregar una síntesis de la información de la literatura sobre la biología de la especie, y 2 identificar la carencia de conocimiento científico y puntos críticos para el desarrollo de su tecnología de cultivo comercial. G. maculatus es un pequeño pez carnívoro, con poblaciones eurihalinas diferenciadas en diadrómicas y dulceacuícolas. Las poblaciones diadrómicas desovan en los estuarios y la larva migra al mar, retornando a la edad de seis meses para metamorfosearse en adulto. Son escasos los estudios de su sistemática, poblaciones y estado larvario en aguas chilenas, pero los correspondientes a alimentación, reproducción y enfermedades son más numerosos. Las hembras de un año desovan, aproximadamente, 1.200 huevos adhesivos pero un número importante muere después del primer desove (40%. La especie tiene un crecimiento rápido (1,1% dia-1 y alto metabolismo, con un promedio de vida de dos años. Se puede cultivar en cautividad, desovar, incubar sus huevos y obtener larvas; los adultos comen starter pelletizado de salmón y crecen en estanques. El protozoo ciliado Ichtyophthirius multifilis (ich produce altas mortalidades, en ejemplares en cautiverio, que pueden ser controladas con baños de sal. Los problemas de investigación a resolver para una futura piscicultura comercial son: identificar y seleccionar las poblaciones adecuadas para cultivo, aumentar el número de huevos desovados por hembra, desarrollar alimentos para larvas y reproductores, y controlar las enfermedades ectoparasitarias. El punto crítico es la masificación de la producción mediante el mejoramiento de las técnicas de reproducción y larvicultura.

  17. Evolutionary history of the fish genus Astyanax Baird & Girard (1854) (Actinopterygii, Characidae) in Mesoamerica reveals multiple morphological homoplasies.

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    Ornelas-García, Claudia Patricia; Domínguez-Domínguez, Omar; Doadrio, Ignacio

    2008-12-22

    Mesoamerica is one of the world's most complex biogeographical regions, mostly due to its complex geological history. This complexity has led to interesting biogeographical processes that have resulted in the current diversity and distribution of fauna in the region. The fish genus Astyanax represents a useful model to assess biogeographical hypotheses due to it being one of the most diverse and widely distributed freshwater fish species in the New World. We used mitochondrial and nuclear DNA to evaluate phylogenetic relationships within the genus in Mesoamerica, and to develop historical biogeographical hypotheses to explain its current distribution. Analysis of the entire mitochondrial cytochrome b (Cytb) gene in 208 individuals from 147 localities and of a subset of individuals for three mitochondrial genes (Cytb, 16 S, and COI) and a single nuclear gene (RAG1) yielded similar topologies, recovering six major groups with significant phylogeographic structure. Populations from North America and Upper Central America formed a monophyletic group, while Middle Central America showed evidence of rapid radiation with incompletely resolved relationships. Lower Central America lineages showed a fragmented structure, with geographically restricted taxa showing high levels of molecular divergence. All Bramocharax samples grouped with their sympatric Astyanax lineages (in some cases even with allopatric Astyanax populations), with less than 1% divergence between them. These results suggest a homoplasic nature to the trophic specializations associated with Bramocharax ecomorphs, which seem to have arisen independently in different Astyanax lineages. We observed higher taxonomic diversity compared to previous phylogenetic studies of the Astyanax genus. Colonization of Mesoamerica by Astyanax before the final closure of the Isthmus of Panama (3.3 Mya) explains the deep level of divergence detected in Lower Central America. The colonization of Upper Mesoamerica apparently

  18. Evolutionary history of the fish genus Astyanax Baird & Girard (1854 (Actinopterygii, Characidae in Mesoamerica reveals multiple morphological homoplasies

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    Doadrio Ignacio

    2008-12-01

    Full Text Available Abstract Background Mesoamerica is one of the world's most complex biogeographical regions, mostly due to its complex geological history. This complexity has led to interesting biogeographical processes that have resulted in the current diversity and distribution of fauna in the region. The fish genus Astyanax represents a useful model to assess biogeographical hypotheses due to it being one of the most diverse and widely distributed freshwater fish species in the New World. We used mitochondrial and nuclear DNA to evaluate phylogenetic relationships within the genus in Mesoamerica, and to develop historical biogeographical hypotheses to explain its current distribution. Results Analysis of the entire mitochondrial cytochrome b (Cytb gene in 208 individuals from 147 localities and of a subset of individuals for three mitochondrial genes (Cytb, 16 S, and COI and a single nuclear gene (RAG1 yielded similar topologies, recovering six major groups with significant phylogeographic structure. Populations from North America and Upper Central America formed a monophyletic group, while Middle Central America showed evidence of rapid radiation with incompletely resolved relationships. Lower Central America lineages showed a fragmented structure, with geographically restricted taxa showing high levels of molecular divergence. All Bramocharax samples grouped with their sympatric Astyanax lineages (in some cases even with allopatric Astyanax populations, with less than 1% divergence between them. These results suggest a homoplasic nature to the trophic specializations associated with Bramocharax ecomorphs, which seem to have arisen independently in different Astyanax lineages. We observed higher taxonomic diversity compared to previous phylogenetic studies of the Astyanax genus. Colonization of Mesoamerica by Astyanax before the final closure of the Isthmus of Panama (3.3 Mya explains the deep level of divergence detected in Lower Central America. The

  19. Alterations in Mc1r gene expression are associated with regressive pigmentation in Astyanax cavefish.

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    Stahl, Bethany A; Gross, Joshua B

    2015-11-01

    Diverse changes in coloration across distant taxa are mediated through alterations in certain highly conserved pigmentation genes. Among these genes, Mc1r is a frequent target for mutation, and many documented alterations involve coding sequence changes. We investigated whether regulatory mutations in Mc1r may also contribute to pigmentation loss in the blind Mexican cavefish, Astyanax mexicanus. This species comprises multiple independent cave populations that have evolved reduced (or absent) melanic pigmentation as a consequence of living in darkness for millions of generations. Among the most salient cave-associated traits, complete absence (albinism) or reduced levels of pigmentation (brown) have long been the focus of degenerative pigmentation research in Astyanax. These two Mendelian traits have been linked to specific coding mutations in Oca2 (albinism) and Mc1r (brown). However, four of the seven caves harboring the brown phenotype exhibit unaffected coding sequences compared to surface fish. Thus, diverse genetic changes involving the same genes likely impact reduced pigmentation among cavefish populations. Using both sequence and expression analyses, we show that certain cave-dwelling populations harboring the brown mutation have substantial alterations to the putative Mc1r cis-regulatory region. Several of these sequence mutations in the Mc1r 5' region were present across multiple, independent cave populations. This study suggests that pigmentation reduction in Astyanax cavefish evolves through a combination of both coding and cis-regulatory mutations. Moreover, this study represents one of the first attempts to identify regulatory alterations linked to regressive changes in cave-dwelling populations of A. mexicanus.

  20. Diet of Astyanax species (Teleostei, Characidae in an Atlantic Forest River in Southern Brazil

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    Fábio Silveira Vilella

    2002-06-01

    Full Text Available Feeding habits of six species of Astyanax from river Maquiné are described. Fishes were sampled bi-monthly from November/95 to September/96 in two zones of the river. Items were identified, counted and had their abundance estimated according to a semi-quantitative scale. Frequency of occurrence, alimentary importance index (IFI values and a similarity analysis of diets for each species-river zone sample were examined. All the species were considered typically omnivorous, with insects and vegetal matter being the most important items in their diet. These species could act as seed dispersers, particularly for macrophytes. Intra-specific spatial differences were not observed in comparisons of samples from two diferent regions of the river, except for A. fasciatus. The presence of Podostemaceae macrophytes in the mid-course of the river seemed to be important both as an autochthonous food resource and as habitat for several organisms preyed by the Astyanax species.Seis espécies do gênero Astyanax, presentes no rio Maquiné, RS, foram estudadas quanto aos seus hábitos alimentares. Os exemplares foram amostrados bimensalmente de novembro de 1995 a setembro de 1996 nas zonas ritral e potamal do rio. Os itens alimentares foram identificados e quantificados de acordo com uma escala semi-quantitativa de abundância, utilizando-se para análise a frequência de ocorrência e um índice de importância alimentar para cada espécie e zona do rio. Análises multivariadas de agrupamento e ordenação foram utilizadas para comparar as dietas intra e interespecíficas. Todas as espécies foram consideradas onivoras, sendo que os itens mais importantes foram os insetos e restos de vegetais superiores. Sugere-se que as espécies estudadas possam atuar como dispersoras de sementes, particularmente para macrófitas. Diferenças espaciais intraespecíficas não foram encontradas, exceto para A. fasciatus. A presença de Podostemaceae no curso médio do rio parece

  1. The sensitivity of lateral line receptors and their role in the behavior of Mexican blind cavefish (Astyanax mexicanus)

    NARCIS (Netherlands)

    Yoshizawa, Masato; Jeffery, William R; van Netten, Sietse M; McHenry, Matthew J

    2014-01-01

    The characid fish species Astyanax mexicanus offers a classic comparative model for the evolution of sensory systems. Populations of this species evolved in caves and became blind while others remained in streams (i.e. surface fish) and retained a functional visual system. The flow-sensitive lateral

  2. Cytogenetic data on Astyanax jacuhiensis (Characidae in the lago Guaíba and tributaries, Brazil

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    Rosiley B. Pacheco

    Full Text Available Cytogenetic analyses were performed in Astyanax jacuhiensis from lago Guaíba, Brazil. The diploid number was 50, with a karyotype composed of 8m+30sm+4st+8a chromosomes, FN = 92. The AgNORs were observed in 2 to 5 chromosomes, with intra- and interindividual variation. The sm pair 8 observed always carried NORs on the short arms, presenting size heteromorphism between homologous. Fluorescence in situ hybridization (FISH with an 18S rDNA probe only confirmed the location of ribosomal cistrons in the sm pair 8, and heteromorphism of these regions between the homologous chromosomes. C-banding revealed the occurrence of weak C-positive heterochromatin in the pericentromeric regions of several chromosomes, in addition to more evident bands interstitially located on some chromosome pairs and in the terminal region of the short arms in pair 8. C-banding plus CMA3 revealed light fluorescent signals in different chromosomes of the karyotype, with a strong terminal site in pair 8, indicating the occurrence of several GC-rich heterochromatic regions in this species. Our results provide the first description of the Astyanax jacuhiensis karyotype, showing karyotype similarities when compared to various populations of A. altiparanae and A. bimaculatus, indicating that chromosomal features are very similar for these three species.

  3. Identification of Astyanax altiparanae (Teleostei, Characidae in the Iguaçu River, Brazil, based on mitochondrial DNA and RAPD markers

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    Prioli Sônia M.A.P.

    2002-01-01

    Full Text Available Astyanax fishes are among the most important food-web components of South America rivers. In the Iguaçu River basin, the Astyanax genus is represented mainly by endemic species. For millions of years, that hydrographic basin has been geographically isolated from the Paraná River basin by the Iguaçu Falls. Recently, a species from the Upper Paraná River basin identified as Astyanax bimaculatus was revised and described as a new species named Astyanax altiparanae Garutti & Britski, 2000. Fauna endemism and geographic isolation triggered interest in investigations to evaluate the identification and genetic relatedness among two A. altiparanae populations from the Upper Paraná River basin and the population identified as A. bimaculatus in the Iguaçu River, upstream from the Iguaçu Falls. Mitochondrial DNA sequences and RAPD markers revealed high genetic diversity within each population, as well as low genetic distance, high gene flow, and high mitochondrial DNA similarity among all three populations. In conjunction with morphological similarities, these results demonstrated that the population presently known as Astyanax bimaculatus in the Iguaçu River should actually be stated as Astyanax altiparanae. Furthermore, it could be inferred that the A. altiparanae population is not endemic and most likely it was recently introduced in the Iguaçu River basin, maintaining the ancestral genetic identity.

  4. A pleiotropic interaction between vision loss and hypermelanism in Astyanax mexicanus cave x surface hybrids.

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    Gross, Joshua B; Powers, Amanda K; Davis, Erin M; Kaplan, Shane A

    2016-06-30

    Cave-dwelling animals evolve various traits as a consequence of life in darkness. Constructive traits (e.g., enhanced non-visual sensory systems) presumably arise under strong selective pressures. The mechanism(s) driving regression of features, however, are not well understood. Quantitative trait locus (QTL) analyses in Astyanax mexicanus Pachón cave x surface hybrids revealed phenotypic effects associated with vision and pigmentation loss. Vision QTL were uniformly associated with reductions in the homozygous cave condition, however pigmentation QTL demonstrated mixed phenotypic effects. This implied pigmentation might be lost through both selective and neutral forces. Alternatively, in this report, we examined if a pleiotropic interaction may exist between vision and pigmentation since vision loss has been shown to result in darker skin in other fish and amphibian model systems. We discovered that certain members of Pachón x surface pedigrees are significantly darker than surface-dwelling fish. All of these "hypermelanic" individuals demonstrated severe visual system malformations suggesting they may be blind. A vision-mediated behavioral assay revealed that these fish, in stark contrast to surface fish, behaved the same as blind cavefish. Further, hypermelanic melanophores were larger and more dendritic in morphology compared to surface fish melanophores. However, hypermelanic melanophores responded normally to melanin-concentrating hormone suggesting darkening stemmed from vision loss, rather than a defect in pigment cell function. Finally, a number of genomic regions were coordinately associated with both reduced vision and increased pigmentation. This work suggests hypermelanism in hybrid Astyanax results from blindness. This finding provides an alternative explanation for phenotypic effect studies of pigmentation QTL as stemming (at least in part) from environmental, rather than exclusively genetic, interactions between two regressive phenotypes. Further

  5. Complex Evolutionary and Genetic Patterns Characterize the Loss of Scleral Ossification in the Blind Cavefish Astyanax mexicanus

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    O’Quin, Kelly E.; Doshi, Pooja; Lyon, Anastasia; Hoenemeyer, Emma; Yoshizawa, Masato; Jeffery, William R.

    2015-01-01

    The sclera is the tough outer covering of the eye that provides structural support and helps maintain intraocular pressure. In some fishes, reptiles, and birds, the sclera is reinforced with an additional ring of hyaline cartilage or bone that forms from scleral ossicles. Currently, the evolutionary and genetic basis of scleral ossification is poorly understood, especially in teleost fishes. We assessed scleral ossification among several groups of the Mexican tetra (Astyanax mexicanus), which exhibit both an eyed and eyeless morph. Although eyed Astyanax surface fish have bony sclera similar to other teleosts, the ossicles of blind Astyanax cavefish generally do not form. We first sampled cavefish from multiple independent populations and used ancestral character state reconstructions to determine how many times scleral ossification has been lost. We then confirmed these results by assessing complementation of scleral ossification among the F1 hybrid progeny of two cavefish populations. Finally, we quantified the number of scleral ossicles present among the F2 hybrid progeny of a cross between surface fish and cavefish, and used this information to identify quantitative trait loci (QTL) responsible for this trait. Our results indicate that the loss of scleral ossification is common–but not ubiquitous–among Astyanax cavefish, and that this trait has been convergently lost at least three times. The presence of wild-type, ossified sclera among the F1 hybrid progeny of a cross between different cavefish populations confirms the convergent evolution of this trait. However, a strongly skewed distribution of scleral ossicles found among surface fish x cavefish F2 hybrids suggests that scleral ossification is a threshold trait with a complex genetic basis. Quantitative genetic mapping identified a single QTL for scleral ossification on Astyanax linkage group 1. We estimate that the threshold for this trait is likely determined by at least three genetic factors which

  6. Astyanax fasciatus as bioindicator of water pollution of Rio dos Sinos, RS, Brazil

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    SCHULZ U. H.

    2001-01-01

    Full Text Available The effects of an increasing downriver pollution gradient on the reproductive system of Astyanax fasciatus were investigated in the Rio dos Sinos, RS. The comparison of mean oocyte diameters, gonadal indices and gonado-somatic relationships of specimens captured in polluted areas with individuals from unpolluted reference sites revealed a significant decrease of these parameters with increasing water pollution. High loads of organic and industrial sewage are considered responsible for these effects. Condition factors showed an inverse relationship, and increased significantly in downriver polluted areas. The declining gonadal indices showed that energy was allocated to somatic growth. The results of the study recommend the use of A. fasciatus in biomonitoring essays.

  7. Genotoxic effects of water from São Francisco River, Brazil, in Astyanax paranae.

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    Ribeiro, Diego Luis; Barcelos, Gustavo Rafael Mazzaron; d'Arce, Luciana Paula Grégio

    2014-09-01

    Aquatic monitoring is an important tool for identifying potential compounds in rivers that may damage the environment. Here, we evaluate the potential genotoxic effects of water samples from São Francisco River (Brazil) using the micronuclei (MN) assay in resident species, Astyanax paranae. Four seasonal collections occurred between the years 2009 and 2010, at three locations between two nearby cities in the region. It was clearly observed an increase of MN frequency in fish caught in the river. This result is most likely due to the sewage contamination from the treatment plant, the waste pesticides from crops and the lack of riparian vegetation along the river, especially during the winter when there was a significant increase in the frequencies of MN. These results indicate that compounds in waters from São Francisco River may have genotoxic effects and consequently, cause damage to the environment as well as to human health.

  8. Variación morfológica de las especies de Astyanax, subgénero Zygogaster (Teleostei, Characidae

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    Ruiz-C., R. I.

    2011-06-01

    Full Text Available Morphological variation of Astyanax species, subgenus Zygogaster (Teleostei, Characidae The diverse Neotropical fish genus Astyanax inhabits a variety of aquatic environments. As with other species in this genus, the taxonomic status and phylogenetic relationships of species of this subgenus remain largely undetermined. Based on 354 individuals, we analyzed the morphological variation of four species of the subgenus Zygogaster (A. atratoensis, A. caucanus, A. filiferus, and A. magdalenae using procrustes analysis and compared findings with two species of the sister group: subgenus Poecilurichthys (A. orthodus and A. superbus. The PCA (Principal Component Analysis and CVA (Canonical Variates Analysis showed morphological affinity between the subgenera and indicated variance in body depth, anterior trend of dorsal fin origin and humeral spot, depression on the dorsal surface of the skull, and ventral displacement of the orbit and snout. The variation in these structures may provide evidence supporting adaptive speciation as an alternative to speciation driven by geographical isolation.

  9. Evolution du système nerveux et du comportement chez le poisson cavernicole aveugle Astyanax mexicanus

    OpenAIRE

    Elipot, Yannick

    2013-01-01

    Astyanax mexicanus is a teleost fish model used for evolution studies. Among the same species, there are several populations of sighted surface fish (SF) that live in Mexican rivers and at least twenty nine populations of blind cavefish (CF) that live in perpetual darkness. Several of these cave populations are independently-evolved, and they derived from surface fish-like ancestors. CF have lost their eyes and their pigmentation, and they have also evolved a number of behavioral traits. Most...

  10. Population structure, fluctuating asymmetry and genetic variability in an endemic and highly isolated Astyanax fish population (Characidae

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    Maria Claudia Gross

    2004-01-01

    Full Text Available Morphological and chromosomal markers were used to infer the structure and genetic variability of a population of fish of the genus Astyanax, geographically isolated at sinkhole 2 of Vila Velha State Park, Paraná, Brazil. Two morphotypes types were observed, the standard phenotype I and phenotype II which showed an anatomical alteration probably due to an inbreeding process. Fluctuating asymmetry (FA analysis of different characters showed low levels of morphological variation among the population from sinkhole 2 and in another population from the Tibagi river (Paraná, Brazil. The Astyanax karyotype was characterized in terms of chromosomal morphology, constitutive heterochromatin and nucleolar organizer regions. Males and females presented similar karyotypes (2n=48, 6M+18SM+14ST+10A with no evidence of a sex chromosome system. One female from sinkhole 2 was a natural triploid with 2n=3x=72 chromosomes (9M+27SM+21ST+15A. The data are discussed regarding the maintenance of population structure and their evolutionary importance, our data suggesting that Astyanax from the Vila Velha State Park sinkhole 2 is a recently isolated population.

  11. Lens apoptosis in the Astyanax blind cavefish is not triggered by its small size or defects in morphogenesis.

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    Hélène Hinaux

    Full Text Available Blindness is a convergent trait in many cave animals of various phyla. Astyanax mexicanus cavefish is one of the best studied cave animals; however the mechanisms underlying eye degeneration in this species are not yet completely understood. The lens seems to play a central role, but only relatively late differentiation defects have been implicated in the cavefish lens apoptosis phenotype so far. Here, we used genetic crosses between Astyanax cavefish and surface fish to confirm that during development, lens size is independent of retina size. We then investigated whether the small size of the cavefish lens could directly cause cell death. Laser ablation experiments of lens placode cells in surface fish embryos showed that a small lens size is not sufficient to trigger lens apoptosis. We further examined potential lens morphogenesis defects through classical histology and live-imaging microscopy. From lens placode to lens ball, we found that lens invagination and formation of the lens epithelium and fiber cells occur normally in cavefish. We conclude that the main and deleterious defect in the Astyanax cavefish lens must concern the molecular control of lens cell function.

  12. Assessment of Water Pollution Signs in the Brazilian Pampa Biome Using Stress Biomarkers in Fish (Astyanax sp.

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    Mauro Nunes

    2015-01-01

    Full Text Available Located in southern Brazil, the Pampa biome has been under constant threat due to improper management of human effluents and use of pesticides. These contaminants accumulate mainly in water resources resulting in chronic poisoning of aquatic biota. Up to date, no studies on the assessment of environmental quality in the Brazilian portion of Pampa biome have been undertaken. Thereby, our main goal in this study was to investigate the ecotoxicological risks caused by human activity in the Santa Maria River, a major water course in the Brazilian Pampa biome. Brain and muscle tissues were used for determining oxidative stress and cholinesterase biomarkers in fish (Astyanax sp. exposed to urban and agricultural effluents. A substantial decrease in fish muscle acetylcholinesterase activity was observed in exposed animals, compared to controls (kept under laboratory conditions. In parallel, increased lipid peroxidation and significant changes in stress-responsive antioxidant enzymes (GST, CAT, GPx, and TrxR were detected. In the fish brain, a significant increase in GST activity is reported. In conclusion, our results showed significant changes in biomarkers of water contamination in Astyanax captured in Santa Maria River, pointing to important levels of water pollution in the region and validating the use of Astyanax in biomonitoring programs within the Pampa biome borders.

  13. Review of species of the Astyanax bimaculatus "caudal peduncle spot" subgroup sensu Garutti & Langeani (Characiformes, Characidae) from the rio La Plata and rio São Francisco drainages and coastal systems of southern Brazil and Uruguay.

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    Lucena, Carlos Alberto S De; Soares, Helena Gouvea

    2016-01-28

    The species of the Astyanax bimaculatus 'caudal peduncle spot' subgroup of the drainages of the rios La Plata and São Francisco, as well as southeastern coastal systems of Brazil and Uruguay, are revised. Two nominal species are considered valid and are redescribed: Astyanax lacustris and A. abramis. Astyanax jacuhiensis, A. asuncionensis and A. altiparanae are recognized as new junior synonyms of A. lacustris. Bertoniolus paraguayensisis recognized as a new junior synonym of A. abramis. The names Astyanax orbignyanus, A. vittatus, and A. borealis are considered species inquirendae. Notes on A. maculisquamis, included in the 'caudal peduncle spot' subgroup from rio Guaporé (rio Madeira drainage), and Astyanax bahiensis from Bahia, mistakenly considered of the same subgroup, are presented.

  14. Cranial asymmetry arises later in the life history of the blind Mexican cavefish, Astyanax mexicanus.

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    Amanda K Powers

    Full Text Available As a consequence of adaptation to the cave environment, the blind Mexican cavefish, Astyanax mexicanus, has evolved several cranial aberrations including changes to bone sizes, shapes and presence of numerous lateral asymmetries. Prior studies of cranial asymmetry in cavefish focused strictly on adult specimens. Thus, the extent to which these asymmetries emerge in adulthood, or earlier in the life history of cavefish, was unknown. We performed a geometric morphometric analysis of shape variation in the chondrocranium and osteocranium across life history in two distinct cavefish populations and surface-dwelling fish. The cartilaginous skull in juveniles was bilaterally symmetric and chondrocranial shape was conserved in all three populations. In contrast, bony skull shapes segregated into significantly distinct groups in adults. Cavefish demonstrated significant asymmetry for the bones surrounding the collapsed eye orbit, and the opercle bone posterior to the eye orbit. Interestingly, we discovered that cavefish also exhibit directional "bends" in skull shape, almost always biased to the left. In sum, this work reveals that asymmetric craniofacial aberrations emerge later in the cavefish life history. These abnormalities may mirror asymmetries in the lateral line sensory system, reflect a 'handedness' in cavefish swimming behavior, or evolve through neutral processes.

  15. Transport of Astyanax altiparanae Garutti and Britski, 2000 in saline water

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    Ana Lúcia Salaro

    2015-08-01

    Full Text Available Two experiments were performed. The first aimed to assess the tolerance of fingerlings Astyanax altiparanae to water salinity. Fish were exposed to salinity of 0, 3, 6, 9, 12 or 15 g NaCl L-1 for 96 hours. The fish mortality was 0%, in the levels of 0, 3 and 6 g L-1; 75% in the level of 9 g L-1and 100% at 12 and 15 g L-1 of common salt. The second experiment aimed to assess the parameters of water quality, mortality and blood glucose during transport. For this, A. altiparanae were stored in plastic bags at 22, 30 and 37 g of fish L-1 stocking densities and salinity of 0, 3, 6 and 9 g L-1, for. Fish showed similar mortality levels in the different salinities and stocking densities. The increase in fish density reduced the dissolved oxygen levels and salinity decreased the pH. The blood glucose levels were higher in those fish with 0 g L-1 salinity and higher stocking densities. The addition of salt to the water reduces the stress responses of A. altiparanae during transport.

  16. Replacement of animal protein with vegetable protein in the diets of Astyanax altiparanae

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    Fábio Rosa Sussel

    2014-09-01

    Full Text Available The aim of this study was to evaluate the effect of replacing animal protein with vegetable protein sources on the productive performance of Astyanax altiparanae (lambari-do-rabo-amarelo. Five experimental diets were formulated with increasing replacement levels of animal protein by vegetable protein. A total of 9000 individuals (initial mean weight 1.18 ± 0.12 g, initial mean length 2.1 ± 0.3 cm were distributed in 20 net cages (1 m3 with a density of 450 ind. m-3. Cages were randomly placed in a pond (180 m2, 1.5 m deep, 10% water renewal per day. After 63 days of cultivation, total count and individual biometrics from 20% of each experimental unit were taken. Mean weight, total length, survival, feed conversion, biomass weight gain and proximate body composition were evaluated. The experimental design was completely randomized with five treatments and four replications. The reduction in the formulation cost achieved by increasing levels of vegetable protein compensated the slight decrease in biomass gain. Besides that, inclusion of vegetable protein resulted in greater fat deposition, suggesting future exploration of A. altiparanae as a functional food.

  17. Intestinal and liver morphometry of the Yellow Tail Tetra (Astyanax altiparanae fed with oregano oil

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    POLLYANNA M.F. FERREIRA

    2016-06-01

    Full Text Available ABSTRACT This study aimed to evaluate the effect of oregano oil on the intestinal and liver morphometry of yellow tail tetra, Astyanax altiparanae. Fish (1.46 ± 0.09 g were kept in a 60-L aquaria, at a stocking density of 0.5 fi sh L-1. Six diets containing varying amounts of oregano oil were evaluated (0.0; 0.5; 1.0; 1.5; 2.0 and 2.5 g of oregano oil kg-1. At the end of 90 days, the fi sh were euthanised. Four intestines and four livers were collected per treatment, which were fi xed in Bouin and embedded in resin. For height and width folds, the absorption surface area and thickness of the muscular layer a positive linear effect of oregano oil was observed. A decrescent linear effect on the total number of goblet cells was also observed. For the cytoplasmic percentage of hepatocytes and liver glycogen, a positive linear effect of oregano oil was observed. There was a decreasing linear effect on the percentage of nuclei in the hepatocytes and capillaries. Thus, the oregano essential oil promotes increased absorption areas, modulates the amount of goblet cells involved in protecting the intestinal mucosa and promotes cytoplasmic increase with greater deposition of liver glycogen in yellow tail tetra.

  18. Curcuma longa as additive in the diet for Astyanax aff. bimaculatus.

    Science.gov (United States)

    de Moraes França Ferreira, Pollyanna; Martins, Maria Tatiana Soares; Caldas, Débora Werneck; Gomes, Juliana Rodrigues; de Oliveira, Jerusa Maria; Salaro, Ana Lucia; Rocha, Juliana Silva; Zuanon, Jener Alexandre Sampaio

    2017-06-01

    The aim of the present study was to evaluate the effect of turmeric (Curcuma longa) as additive in the diet for Astyanax aff. bimaculatus. Fish (0.83 ± 0.04 g) were fed, for 60 days, with six diets containing 0.0, 20.0, 40.0, 60.0, 80.0, and 100.0 g turmeric kg -1 feed. There was an increasing linear effect of turmeric on the thickness of the muscular layer, and height and width of the folds of the intestine. In the liver, a quadratic effect was observed of turmeric on the percentage of hepatocyte cytoplasm and a decreasing linear effect on the percentage of sinusoid capillaries. A quadratic effect was also observed of turmeric on the liver glycogen. There was no effect of turmeric on the antioxidant activity in the liver, carcass composition or productive performance of the fish. Thus, we concluded that Curcuma longa has trophic effects on the epithelium and the muscular layer of the intestine of A. aff. bimaculatus. Additionally, low levels of Curcuma longa cause increased deposition of liver glycogen and high levels cause reduction.

  19. The lateral line system is not necessary for rheotaxis in the Mexican blind cavefish (Astyanax fasciatus).

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    Van Trump, William J; McHenry, Matthew J

    2013-11-01

    Fish resist being swept downstream by swimming against a current. Mexican blind cavefish (Astyanax fasciatus) exhibit this innate behavior, rheotaxis, without the aid of vision, but it has been debated whether this ability requires sensing flow with the lateral line system. We tested the role of the lateral line by comparing swimming in a flow chamber in a group of cavefish with a compromised lateral line with a control group. Consistent with previous studies, we found that cavefish orient toward flow and more frequently swim upstream at a higher flow speed. We found that these responses to flow were indistinguishable between fish with compromised and functioning lateral line systems. Rheotaxis was also unaltered by exposing fish to varying degrees of turbulence. These results suggest that the sensing of flow is unnecessary for rheotaxis in cavefish. It appears that tactile stimuli provide a sufficient means of executing this behavior in fish and that rheotaxis may not be a major function of the lateral line system.

  20. Gonadotropin subunits of the characiform Astyanax altiparanae : Molecular characterization, spatiotemporal expression and their possible role on female reproductive dysfunction in captivity

    NARCIS (Netherlands)

    de Jesus, Lázaro Wender O; Bogerd, Jan|info:eu-repo/dai/nl/098250531; Vieceli, Felipe M; Branco, Giovana S; Camargo, Marília P; Cassel, Mônica; Moreira, Renata G; Yan, Chao Y I; Borella, Maria I.

    2017-01-01

    To better understand the endocrine control of reproduction in Characiformes and the reproductive dysfunctions that commonly occur in migratory fish of this order when kept in captivity, we chose Astyanax altiparanae, which has asynchronous ovarian development and multiple spawning events, as model

  1. Molecular cloning and expression analysis of dmrt1 and sox9 during gonad development and male reproductive cycle in the lambari fish, astyanax altiparanae

    NARCIS (Netherlands)

    Adolfi, Mateus C.; Carreira, Ana C O; Jesus, Lázaro W O; Bogerd, Jan; Funes, Rejane M.; Schartl, Manfred; Sogayar, Mari C.; Borella, Maria I.

    2015-01-01

    Background: The dmrt1 and sox9 genes have a well conserved function related to testis formation in vertebrates, and the group of fish presents a great diversity of species and reproductive mechanisms. The lambari fish (Astyanax altiparanae) is an important Neotropical species, where studies on

  2. Effects of acidic water, aluminum, and manganese on testicular steroidogenesis in Astyanax altiparanae.

    Science.gov (United States)

    Kida, Bianca Mayumi Silva; Abdalla, Raisa Pereira; Moreira, Renata Guimarães

    2016-10-01

    Metals can influence the gonadal steroidogenesis and endocrine systems of fish, thereby affecting their reproduction. The effects of aluminum and manganese in acidic water were investigated on steroidogenesis in sexually mature male Astyanax altiparanae. Whether mature male fish recover from the effects of metals in metal-free water was also assessed. The fish were exposed to 0.5 mg L(-1) of isolated or combined aluminum and manganese in acidic pH (5.5) to keep the metals bioavailable. The fish underwent 96 h of acute exposure, and samples were taken 24 and 96 h after the beginning of the experiment. The fish were then maintained in metal-free water for 96 h. Plasma levels of testosterone, 11-ketotestosterone, 17β-estradiol, and cortisol were measured. Acidic water increased the plasma concentration of testosterone and 11-ketotestosterone. Aluminum increased the testosterone levels after 96 h of exposure. Manganese increased the 17β-estradiol levels after 24 h of exposure and maintained at high levels until the end of the experiment. With the exception of acidic pH, which increased cortisol levels after 24 h of exposure, no changes were observed in this corticosteroid during the acute experiment. Aluminum and manganese together also altered steroid levels but without a standard variation. The fish recovered from the effects of most exposure conditions after 96 h in metal-free water. A. altiparanae could use reproductive tactics to trigger changes in testicular steroidogenesis by accelerating spermatogenesis and spermiogenesis, which may interfere with their reproductive dynamics.

  3. A Flow Cytometry Protocol to Estimate DNA Content in the Yellowtail Tetra Astyanax altiparanae.

    Science.gov (United States)

    Xavier, Pedro L P; Senhorini, José A; Pereira-Santos, Matheus; Fujimoto, Takafumi; Shimoda, Eduardo; Silva, Luciano A; Dos Santos, Silvio A; Yasui, George S

    2017-01-01

    The production of triploid yellowtail tetra Astyanax altiparanae is a key factor to obtain permanently sterile individuals by chromosome set manipulation. Flow cytometric analysis is the main tool for confirmation of the resultant triploids individuals, but very few protocols are specific for A. altiparanae species. The current study has developed a protocol to estimate DNA content in this species. Furthermore, a protocol for long-term storage of dorsal fins used for flow cytometry analysis was established. The combination of five solutions with three detergents (Nonidet P-40 Substitute, Tween 20, and Triton X-100) at 0.1, 0.2, and 0.4% concentration was evaluated. Using the best solution from this first experiment, the addition of trypsin (0.125, 0.25, and 0.5%) and sucrose (74 mM) and the effects of increased concentrations of the detergents at 0.6 and 1.2% concentration were also evaluated. After adjustment of the protocol for flow cytometry, preservation of somatic tissue or isolated nuclei was also evaluated by freezing (at -20°C) and fixation in saturated NaCl solution, acetic methanol (1:3), ethanol, and formalin at 10% for 30 or 60 days of storage at 25°C. Flow cytometry analysis in yellowtail tetra species was optimized using the following conditions: lysis solution: 9.53 mM MgCl2.7H20; 47.67 mM KCl; 15 mM Tris; 74 mM sucrose, 0.6% Triton X-100, pH 8.0; staining solution: Dulbecco's PBS with DAPI 1 μg mL(-1); preservation procedure: somatic cells (dorsal fin samples) frozen at -20°C. Using this protocol, samples may be stored up to 60 days with good accuracy for flow cytometry analysis.

  4. Origin of B chromosomes in the genus Astyanax (Characiformes, Characidae) and the limits of chromosome painting.

    Science.gov (United States)

    de A Silva, Duílio M Z; Daniel, Sandro Natal; Camacho, Juan Pedro M; Utsunomia, Ricardo; Ruiz-Ruano, Francisco J; Penitente, Manolo; Pansonato-Alves, José Carlos; Hashimoto, Diogo Teruo; Oliveira, Claudio; Porto-Foresti, Fábio; Foresti, Fausto

    2016-06-01

    Eukaryote genomes are frequently burdened with the presence of supernumerary (B) chromosomes. Their origin is frequently investigated by chromosome painting, under the hypothesis that sharing the repetitive DNA sequences contained in the painting probes is a sign of common descent. However, the intragenomic mobility of many anonymous DNA sequences contained in these probes (e.g., transposable elements) adds high uncertainty to this conclusion. Here we test the validity of chromosome painting to investigate B chromosome origin by comparing its results for seven B chromosome types in two fish species genus Astyanax, with those obtained (1) by means of the physical mapping of 18S ribosomal DNA (rDNA), H1 histone genes, the As51 satellite DNA and the (AC)15 microsatellite, and (2) by comparing the nucleotide sequence of one of these families (ITS regions from ribosomal DNA) between genomic DNA from B-lacking individuals in both species and the microdissected DNA from two metacentric B chromosomes found in these same species. Intra- and inter-specific painting suggested that all B chromosomes that were assayed shared homologous DNA sequences among them, as well as with a variable number of A chromosomes in each species. This finding would be consistent with a common origin for all seven B chromosomes analyzed. By contrast, the physical mapping of repetitive DNA sequences failed to give support to this hypothesis, as no more than two B-types shared a given repetitive DNA. Finally, sequence analysis of the ITS regions suggested that at least some of the B chromosomes could have had a common origin.

  5. Gene flow and population structure in the Mexican blind cavefish complex (Astyanax mexicanus

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    Bradic Martina

    2012-01-01

    Full Text Available Abstract Background Cave animals converge evolutionarily on a suite of troglomorphic traits, the best known of which are eyelessness and depigmentation. We studied 11 cave and 10 surface populations of Astyanax mexicanus in order to better understand the evolutionary origins of the cave forms, the basic genetic structuring of both cave and surface populations, and the degree to which present day migration among them affects their genetic divergence. Results To assess the genetic structure within populations and the relationships among them we genotyped individuals at 26 microsatellite loci. We found that surface populations are similar to one another, despite their relatively large geographic separation, whereas the cave populations are better differentiated. The cave populations we studied span the full range of the cave forms in three separate geographic regions and have at least five separate evolutionary origins. Cave populations had lower genetic diversity than surface populations, correlated with their smaller effective population sizes, probably the result of food and space limitations. Some of the cave populations receive migrants from the surface and exchange migrants with one another, especially when geographically close. This admixture results in significant heterozygote deficiencies at numerous loci due to Wahlund effects. Cave populations receiving migrants from the surface contain small numbers of individuals that are intermediate in both phenotype and genotype, affirming at least limited gene flow from the surface. Conclusions Cave populations of this species are derived from two different surface stocks denoted "old" and "new." The old stock colonized caves at least three times independently while the new stock colonized caves at least twice independently. Thus, the similar cave phenotypes found in these caves are the result of repeated convergences. These phenotypic convergences have occurred in spite of gene flow from surface

  6. Morphometric variation between two morphotypes within the Astyanax Baird and Girard, 1854 (Actinopterygii: Characidae) genus, from a Mexican tropical lake.

    Science.gov (United States)

    Ornelas-García, Claudia P; Bastir, Markus; Doadrio, Ignacio

    2014-07-01

    Phenotypic variation is important for evolutionary processes because it can allow local adaptation, promote genetic segregation, and ultimately give rise to speciation. Lacustrine systems provide a unique opportunity to study the mechanisms by which sister species can co-occur by means of ecological segregation. The fish genus Astyanax is characterized by high levels of phenotypic variability, providing an excellent model for the study of local specialization. Here, we analyze the morphological specializations through geometric morphometrics of two sympatric species described as different genera: Bramocharax caballeroi endemic to Lake Catemaco, and the widely distributed Astyanax aeneus. Additionally, we assess the correlation between phenotypic and genetic structure, and the phylogenetic signal of morphological variation. We examined body size and shape variation in 196 individuals and analyzed mitochondrial cytochrome b sequences in 298 individuals. Our results confirm the striking morphological divergence among the sympatric characids. Differences between them were mainly found in the body depth and profile and orientation of the head, where B. caballeroi in contrast with the A. aeneus, presented a fusiform body and an upward mouth. Moreover, different growth trajectories were observed among morphotypes, suggesting that a heterochronic process could be involved in the diversification of our study system. Morphological differences did not correspond with the molecular differentiation, suggesting high levels of homoplasy among the lineages of B. caballeroi morphs. © 2014 Wiley Periodicals, Inc.

  7. La dieta y fauna de endoparásitos del pejesapo Gobiesox marmoratus Jenyns, 1842 (Pisces: Gobiesocidae en el litoral central de Chile están conectadas pero no correlacionadas Feeding habits and endoparasite fauna of the clingfish Gobiesox marmoratus Jenyns, 1842 (Pisces: Gobiesocidae on the central coast of Chile are intertwined, but not correlated

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    M. Cecilia Pardo-Gandarillas

    2004-12-01

    Full Text Available Se documenta una alta similitud en la composición de la fauna parasitaria y de la dieta de 108 ejemplares del pejesapo Gobiesox marmoratus Jenyns, 1842 recolectados de la costa de la zona centro-sur de Chile, desde tres localidades separadas por al menos 400 km de su(s vecina(s. La longitud total de los pejesapos fue similar entre localidades y su parasitofauna estuvo compuesta por 16 taxa de metazoos (incluyendo cinco Myxozoa. En el 38,8 % de los 108 pejesapos se encontraron parásitos, en tanto que en el 32,4 % de los mismos ejemplares había contenido estomacal, en los que se determinaron 37 ítems presa. La aún más baja ocurrencia conjunta de parásitos y presas imposibilitó el uso de parejas de datos parasitarios y dietarios, para evaluar, por ejemplo, si había correlación entre la amplitud dietaria y la riqueza parasitaria. Aunque la composición de la fauna de endoparásitos necesariamente depende de la composición de la dieta de los pejesapos, encontramos muy pocos parásitos en uno de los sitios de estudio. Es decir, las propiedades numéricas de este sistema hospedador-parásito limitaron la posibilidad de hallar asociaciones entre ambos tipos de variables. Tanto la composición de la dieta como de las infracomunidades de parásitos variaban con la ontogenia del huésped. La dieta de los pejesapos juveniles y adultos consistía principalmente de anfípodos, crustáceos decápodos y moluscos en las tres localidades. La similitud de los descriptores numéricos de la dieta y de las infracomunidades (abundancia total, diversidad y riqueza entre las localidades, en parte puede deberse al escaso tamaño corporal máximo alcanzado por G. marmoratus, a la escasa longitud total del tracto digestivo, a las diferencias en las tasas de ingreso y tiempo de residencia de parásitos y presas, al nivel de resolución taxonómica alcanzado en presas y/o parásitos, y al efecto de decidir excluir o no de los análisis a las especies rarasA high

  8. Two - three loci control scleral ossicle formation via epistasis in the cavefish Astyanax mexicanus.

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    Anastasia Lyon

    Full Text Available The sclera is the protective outer layer of the eye. In fishes, birds, and reptiles, the sclera may be reinforced with additional bony elements called scleral ossicles. Teleost fish vary in the number and size of scleral ossicles; however, the genetic mechanisms responsible for this variation remain poorly understood. In this study, we examine the inheritance of scleral ossicles in the Mexican tetra, Astyanax mexicanus, which exhibits both a cave morph and a surface fish morph. As these morphs and their hybrids collectively exhibit zero, one, and two scleral ossicles, they represent a microcosm of teleost scleral ossicle diversity. Our previous research in F2 hybrids of cavefish from Pachón cave and surface fish from Texas suggested that three genes likely influence the formation of scleral ossicles in this group through an epistatic threshold model of inheritance, though our sample size was small. In this study, we expand our sample size using additional hybrids of Pachón cavefish and Mexican surface fish to (1 confirm the threshold model of inheritance, (2 refine the number of genes responsible for scleral ossicle formation, and (3 increase our power to detect quantitative trait loci (QTL for this trait. To answer these three questions, we scored surface fish and cavefish F2 hybrids for the presence of zero, one, or two scleral ossicles. We then analyzed their distribution among the F2 hybrids using a chi-square (χ2 test, and used a genetic linkage map of over 100 microsatellite markers to identify QTL responsible for scleral ossicle number. We found that inheritance of scleral ossicles follows an epistatic threshold model of inheritance controlled by two genes, which contrasts the three-locus model estimated from our previous study. Finally, the combined analysis of hybrids from both crosses identified two strong QTL for scleral ossicle number on linkage groups 4.2 and 21, and a weaker QTL on linkage group 4.1. Scleral ossification remains

  9. Reproductive traits and population structure of Astyanax aeneus (Characiformes: Characidae from a subtropical river in Mexico

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    Patricia Trujillo-Jiménez

    2013-06-01

    Full Text Available Champotón River is an unknown area within the Mesoamerican hotspot in Southestern México. Reproductive traits and population structure of Astyanax aeneus were analyzed along an environmental gradient of the upper, middle and lower sections of the river, where diverse environmental factors were recorded. For this, nets were cast for 1h at each site and A. aeneus were collected from all sections with sweep nets (5 and 10m long by 5m deep, 0.03m mesh size and a casting net (0.05m mesh size. At each study site and campaign, a total of 80 specimens (in average were collected and were fixed in 10% formaldehyde for further analysis. Population structure by size was analyzed for each study site, based on the relative frequencies by standard length classes. The length-weight relationship was determined, and the identification of gonadal developmental stages, reproductive period, size at first sexual maturity, relative fecundity, sex ratio and somatic indexes (gonadosomatic, hepatosomatic and Fulton’s condition factor were also assessed. Seven size classes were found in the upper and middle sections, and nine downstream, with seasonal and spatial pattern in size-class frequency distribution. Size at first maturity was 45.7mm for females and 40.8mm for males. The maximum relative fecundity was recorded at the downstream site and was positively correlated with body weight and standard length. Sex ratio (1.8:1 males: females differed significantly from expected values (1:1. Gonadosomatic index scores indicated that the reproductive period of this species in the Champotón River was from April to July, during the warm and wet season. Hepatosomatic index was negatively correlated with the Gonadosomatic index, evidencing transfer of energy from the liver towards gamete production. This strategy enabled A. aeneus to maintain robustness during the study period with tiny changes in condition factor. A. aeneus in the Champotón River, as opposed to South

  10. Cytogenetic analysis in the incertae sedis species Astyanax altiparanae Garutti and Britzki, 2000 and Hyphessobrycon eques Steindachner, 1882 (Characiformes, Characidae) from the upper Paraná river basin

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    Martinez, Emanuel R. M.; Alves, Anderson L.; Silveira, Sara M.; Foresti, Fausto; Oliveira, Claudio

    2012-01-01

    Abstract Cytogenetic analyses were accomplished in two populations of Astyanax altiparanae Garutti & Britzki, 2000 and one population of Hyphessobrycon eques Steindachner, 1882, considered incertae sedis in Characidae family. Two populations of Astyanax altiparanae (Mogi-Guaçu and Tietê rivers) presented 2n=50, with the same karyotype formula: 6M+12SM+20ST+12A (FN=88). Hyphessobrycon eques from Capivara river presented 2n=52 and karyotype formula 14M+16SM+4ST+18A (FN=86). In each karyotype, the nucleolus organizer regions were detected at the end of the short arm of a single medium-sized subtelocentric chromosome. The Chromomycin A3 (CMA3) marking is coincident for the NORs in chromosomes of the two species and present additionally in two different chromosomes of Astyanax altiparanae thus showinginterpopulation differences in this species. In Hyphessobrycon eques, weak heterochromatic blocks in the position of centromeres and telomeres of most chromosomes and negative C-banding for the NOR bearing chromosome were visualized. The obtained results contribute both to the understanding of karyotype evolution of these species and to the clarifying their phylogenetic relationships. PMID:24260651

  11. Three sympatric karyomorphs in the fish Astyanax fasciatus (Teleostei, Characidae do not seem to hybridize in natural populations

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    Maressa Ferreira-Neto

    2012-01-01

    Full Text Available Ninety individuals of the characid fish Astyanax fasciatus (Cuvier, 1819 were collected at Água da Madalena stream (Botucatu, São Paulo, Brazil and analyzed for diploid chromosome number 2n and karyotype composition as well as for the chromosomal location of the 5S and 18S ribosomal DNA (rDNA. Whereas no chromosome differences were associated with sex, three different karyomorphs with diploid chromosome numbers 2n=46, 2n=48 and 2n=50 were found. No intermediate 2n numbers were discovered. The 2n=50 karyomorph showed some differences in 18S rDNA location compared to the two other karyomorphs. Finally, all specimens with the 2n=46 karyomorph showed the presence of a partly heterochromatic macro supernumerary chromosome, which was absent in all individuals with the two other karyomorphs. All these results suggest that indviduals of the three different karyomorphs are not likely to hybridize in the examined populations. Our findings strongly suggest the presence of three separate species (sensu biological species concept easily diagnosed on the basis of differences in the diploid chromosome numbers and other chromosomal markers.

  12. Morphology of the urogenital papilla and its component ducts in Astyanax altiparanae Garutti & Britski, 2000 (Characiformes: Characidae

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    Diógenes Henrique de Siqueira-Silva

    Full Text Available The histological description of the urogenital papilla is an important tool to comprehension of the reproductive mechanisms in fish, as well as a pre-requisite to germ cell transplantation in adult fish, besides to be a good biological indicator to environmental changes. Was performed the histological description of the urogenital papilla and its component ducts in the tetra Astyanax altiparanae. The genital and urinay ducts pass separately throughout most part of its extension, joining in a single duct before opening. In males this opening is asymmetric and seems to have double origin, being completely surrounded by striated muscle fibers, while in females it is symmetric and the muscle fibers does not surround it totally. Spermatic duct and oviduct undergo changes throughout their extension, mainly in the morphology of the surrounding epithelium. In the spermatic duct, squamous epithelial cells change to columnar and cuboid with possible secretory activity, close to testes. In the oviduct, anteriorly epithelial cells are also squamous, however, close to ovary there are lamellae composed by a pseudostratified epithelium with columnar and cuboid cells. The urinary duct is highly similar for both sexes presenting globoid cells, which description is known in mammals, however, rare in fish.

  13. Estimation of the dietary essential amino acid requirements of colliroja Astyanax fasciatus by using the ideal protein concept

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    Wilson Massamitu Furuya

    2015-11-01

    Full Text Available Colliroja, Astyanax fasciatus, is a new aquaculture species, and information on its dietary essential amino acid requirements is lacking. The whole body composition of 120 farmed fish (16.2 ± 8.8 g was determined to estimate the dietary essential amino acid requirement based on the ideal protein concept ((each essential amino acid/lysine x100, and the findings were correlated to the whole body essential amino acid content of Nile tilapia Oreochromis niloticus. The dietary essential amino acids, including cysteine and tyrosine, accounted for 5.46, 4.62, 1.16, 3.28, 5.63, 2.01, 2.59, 2.84, 4.66, 3.39, 0.65, and 3.51% of the total protein for lysine, arginine, histidine, isoleucine, leucine, methionine, methionine+tyrosine, phenylalanine, phenylalanine+tyrosine, threonine, tryptophan, and valine, respectively. There were positive linear and high correlations (r = 0.971 between the whole body amino acid profiles of colliroja and Nile tilapia. Thus, the whole body amino acid profile of colliroja might be used to estimate accurately the essential amino acid requirement.

  14. Spatial and temporal biomarkers responses of Astyanax jacuhiensis (Cope, 1894(Characiformes: Characidae from the middle rio Uruguai, Brazil

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    Vania Lucia Loro

    Full Text Available Due to intense agricultural activity in the rio Uruguai (South Brazil, there is the potential for aquatic contamination by agrochemicals. In this region, there are many reservoirs to meet the water demand for rice fields, forming lentic environments. In line with this information, the aim of this study was to show a comparative analysis of some biomarkers, such as lipid peroxidation (TBARS, gluthatione S-transferase (GST, non-protein thiols (NPSH, amino acids (AA and piscine micronucleus tests (MNE in Astyanax jacuhiensis from lentic and lotic environments in the middle rio Uruguai region, comparing warm and cold seasons. Eight pesticides were found in water samples, with propoxur having the highest concentration found in both environments and seasons. Fish from the warm season showed higher levels of biochemical biomarkers, and fish from the cold season showed higher levels of MNE and AA. TBARS and AA presented higher levels in fish from the river, while GST, NPSH, MNE and AA presented higher levels in fish from dams. These environments have different characteristics in terms of redox potential, aeration, sedimentation, trophic structure, agrochemicals input and others, which may affect the physiological and biochemical responses of fish in against adverse situations.

  15. A potential benefit of albinism in Astyanax cavefish: downregulation of the oca2 gene increases tyrosine and catecholamine levels as an alternative to melanin synthesis.

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    Bilandžija, Helena; Ma, Li; Parkhurst, Amy; Jeffery, William R

    2013-01-01

    Albinism, the loss of melanin pigmentation, has evolved in a diverse variety of cave animals but the responsible evolutionary mechanisms are unknown. In Astyanax mexicanus, which has a pigmented surface dwelling form (surface fish) and several albino cave-dwelling forms (cavefish), albinism is caused by loss of function mutations in the oca2 gene, which operates during the first step of the melanin synthesis pathway. In addition to albinism, cavefish have evolved differences in behavior, including feeding and sleep, which are under the control of the catecholamine system. The catecholamine and melanin synthesis pathways diverge after beginning with the same substrate, L-tyrosine. Here we describe a novel relationship between the catecholamine and melanin synthesis pathways in Astyanax. Our results show significant increases in L-tyrosine, dopamine, and norepinephrine in pre-feeding larvae and adult brains of Pachón cavefish relative to surface fish. In addition, norepinephrine is elevated in cavefish adult kidneys, which contain the teleost homologs of catecholamine synthesizing adrenal cells. We further show that the oca2 gene is expressed during surface fish development but is downregulated in cavefish embryos. A key finding is that knockdown of oca2 expression in surface fish embryos delays the development of pigmented melanophores and simultaneously increases L-tyrosine and dopamine. We conclude that a potential evolutionary benefit of albinism in Astyanax cavefish may be to provide surplus L-tyrosine as a precursor for the elevated catecholamine synthesis pathway, which could be important for adaptation to the challenging cave environment.

  16. A potential benefit of albinism in Astyanax cavefish: downregulation of the oca2 gene increases tyrosine and catecholamine levels as an alternative to melanin synthesis.

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    Helena Bilandžija

    Full Text Available Albinism, the loss of melanin pigmentation, has evolved in a diverse variety of cave animals but the responsible evolutionary mechanisms are unknown. In Astyanax mexicanus, which has a pigmented surface dwelling form (surface fish and several albino cave-dwelling forms (cavefish, albinism is caused by loss of function mutations in the oca2 gene, which operates during the first step of the melanin synthesis pathway. In addition to albinism, cavefish have evolved differences in behavior, including feeding and sleep, which are under the control of the catecholamine system. The catecholamine and melanin synthesis pathways diverge after beginning with the same substrate, L-tyrosine. Here we describe a novel relationship between the catecholamine and melanin synthesis pathways in Astyanax. Our results show significant increases in L-tyrosine, dopamine, and norepinephrine in pre-feeding larvae and adult brains of Pachón cavefish relative to surface fish. In addition, norepinephrine is elevated in cavefish adult kidneys, which contain the teleost homologs of catecholamine synthesizing adrenal cells. We further show that the oca2 gene is expressed during surface fish development but is downregulated in cavefish embryos. A key finding is that knockdown of oca2 expression in surface fish embryos delays the development of pigmented melanophores and simultaneously increases L-tyrosine and dopamine. We conclude that a potential evolutionary benefit of albinism in Astyanax cavefish may be to provide surplus L-tyrosine as a precursor for the elevated catecholamine synthesis pathway, which could be important for adaptation to the challenging cave environment.

  17. Biologia reprodutiva de Astyanax henseli (Teleostei, Characidae do curso superior do Rio dos Sinos, RS, Brasil Reproductive biology of Astyanax henseli (Teleostei, Characidae in the upper Rio dos Sinos, RS, Brazil

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    Renato B Dala-Corte

    2010-09-01

    Full Text Available No presente estudo é descrita a biologia reprodutiva de uma população de Astyanax henseli Melo & Buckup, 2006 do curso superior do rio dos Sinos, Caraá, Rio Grande do Sul, Brasil. Foram analisados 336 exemplares, sendo 169 machos, 154 fêmeas e 13 cujo sexo não foi possível ser determinado. O período reprodutivo teve aproximadamente cinco meses de duração, ocorrendo entre agosto e dezembro, com pico do índice gonadossomático (IGS em outubro, correspondendo ao final do inverno e a primavera no hemisfério sul. Não houve correlação estatisticamente significativa do IGS com os fatores abióticos (temperatura, precipitação e fotoperíodo. No entanto, sugere-se que estes fatores estejam atuando como desencadeadores da maturação gonadal. Fatores bióticos como o índice de repleção estomacal (IR e índice hepatossomático (IHS, também não mostraram correlação estatisticamente significativa com o IGS. Apesar disso, os valores de IR indicam que A. henseli continua se alimentando ativamente durante o período reprodutivo, enquanto que os baixos valores de IHS durante do pico reprodutivo sugerem um maior gasto das reservas hepáticas neste período. A proporção sexual de 1:1 foi encontrada ao longo dos meses do ano, nas classes de comprimento e na população como um todo. O comprimento de primeira maturação gonadal foi estabelecido em 69 mm para os machos e 60 mm para as fêmeas. A média da fecundidade absoluta foi de 3.038 ovócitos e a da fecundidade relativa 0,13 ovócitos mg-1. O desenvolvimento ovocitário indicou uma desova total.This study describes the reproductive biology of a population of Astyanax henseli Melo & Buckup, 2006 from the upper Rio dos Sinos, Caraá, Rio Grande do Sul, Brazil. A total of 336 specimens was analyzed, comprising 169 males, 154 females and 13 individuals of undetermined sex. The reproductive season lasted approximately five months, from August to December, gonadossomatic index (GSI peaked

  18. Chromosomal Mapping of Repetitive DNA Sequences in Five Species of Astyanax (Characiformes, Characidae) Reveals Independent Location of U1 and U2 snRNA Sites and Association of U1 snRNA and 5S rDNA.

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    Silva, Duilio M Z A; Utsunomia, Ricardo; Pansonato-Alves, José C; Oliveira, Cláudio; Foresti, Fausto

    2015-01-01

    Astyanax is a genus of Characidae fishes currently composed of 155 valid species. Previous cytogenetic studies revealed high chromosomal diversification among them, and several studies have been performed using traditional cytogenetic techniques to investigate karyotypes and chromosomal locations of 18S and 5S rDNA genes. However, only a few studies are currently available about other repetitive sequences. Here, the chromosomal location of small nuclear RNA genes, identified as U1 and U2 snRNA clusters, was established and compared to the distribution of 5S rDNA and histone clusters in 5 Astyanax species (A. paranae, A. fasciatus, A. bockmanni, A. altiparanae, and A. jordani) using FISH. The cytogenetic mapping of U1 and U2 snRNA demonstrated a conserved pattern in the number of sites per genome independent of the location in Astyanax species. The location of the U1 snRNA gene was frequently associated with 5S rDNA sequences, indicating a possible interaction between the distinct repetitive DNA families. Finally, comparisons involving the location of U1 and U2 snRNA clusters in the chromosomes of Astyanax species revealed a very diverse pattern, suggesting that many rearrangements have occurred during the diversification process of this group. © 2015 S. Karger AG, Basel.

  19. Environmental risk assessment in five rivers of Parana River basin, Southern Brazil, through biomarkers in Astyanax spp.

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    Barros, Ivaldete Tijolin; Ceccon, Juliana Parolin; Glinski, Andressa; Liebel, Samuel; Grötzner, Sonia Regina; Randi, Marco Antonio Ferreira; Benedito, Evanilde; Ortolani-Machado, Claudia Feijó; Filipak Neto, Francisco; de Oliveira Ribeiro, Ciro Alberto

    2017-07-01

    In the current study, water quality of five river sites in Parana River basin (Brazil), utilized for public water supply, was assessed through a set of biomarkers in fish Astyanax spp. Population growth and inadequate use of land are challenges to the preservation of biodiversity and resources such as water. Some physicochemical parameters as well as somatic indexes, gills and liver histopathology, genotoxicity, and biochemical biomarkers were evaluated. The highest gonadosomatic index (GSI) and antioxidant parameters (catalase and glutathione S-transferase activities, non-protein thiols), as well as the lowest damage to biomolecules (lipid peroxidation, protein carbonylation, DNA damage) were observed in site 0 (Piava River), which is located at an environmental protected area. Site 1, located in the same river, but downstream site 0 and outside the protection area, presents some level of impact. Fish from site 2 (Antas River), which lack of riparian forest and suffer from silting, presented the highest micronucleus incidence and no melanomacrophages. Differently, individuals from site 3 (Xambrê River) and site 4 (Pinhalzinho River) which receive surface runoff from Umuarama city, urban and industrial sewage, have the highest incidences of liver and gill histopathological alterations, including neoplasia, which indicated the worst health conditions of all sites. In particular, site 4 had high levels of total nitrogen and ammonia, high turbidity, and very low oxygen levels, which indicate important chemical impact. Comparison of the biomarkers in fish allowed classification of the five sites in terms of environmental impact and revealed that sites 3 and 4 had particular poor water quality.

  20. DNA sequences of troglobitic nicoletiid insects support Sierra de El Abra and the Sierra de Guatemala as a single biogeographical area: Implications for Astyanax

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    Luis Espinasa

    2014-03-01

    Full Text Available The blind Mexican tetra fish, Astyanax mexicanus, has become the most influential model for research of cave adapted organisms. Many authors assume that the Sierra de Guatemala populations and the Sierra de El Abra populations are derived from two independent colonizations. This assumption arises in part from biogeography. The 100 m high, 100 m wide Servilleta Canyon of the Boquillas River separates both mountain ranges and is an apparent barrier for troglobite dispersion. Anelpistina quinterensis (Nicoletiidae, Zygentoma, Insecta is one of the most troglomorphic nicoletiid silverfish insects ever described. 16S rRNA sequences support that this species migrated underground to reach both mountain ranges within less than 12,000 years. Furthermore, literature shows a plethora of aquatic and terrestrial cave restricted species that inhabit both mountain ranges. Thus, the Servilleta canyon has not been an effective biological barrier that prevented underground migration of troglobites between the Sierra de Guatemala and the Sierra de El Abra. The Boquillas River has changed its course throughout time. Caves that in the past connected the two Sierras were only recently geologically truncated by the erosion of the new river course. It is likely that, with the geological changes of the area and throughout the 2-8 million years of evolutionary history of cave Astyanax, there have been opportunities to migrate across the Servilleta canyon.

  1. The occurence of black spot disease in Astyanax aff. fasciatus(characiformes: characidae in the Guaíba Lake basin, RS, Brazil

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    F Flores-Lopes

    Full Text Available Black spot disease is common in freshwater fish and is usually caused by the metacercaria stage of digenetic trematodes, normally from the Diplostomidae family. The present study evaluated the prevalence and intensity of this disease in Astyanax aff. fasciatus(Teleostei: Characiformes in the Guaíba Lake basin (RS, Brazil, including body parts assessment and the points of sampling with higher occurrence of black spots. Fish samples were taken seasonally from December 2002 until October 2004. The samples were collected with the use of a seine net at eleven points. The specimens were fixed in 10% formalin and stored in 70% ethanol. Black spot disease showed a low frequency in the Guaíba lake basin (2.07% and no specificity to the species Astyanax aff. fasciatus was observed. A high prevalence among the individuals and high intensity of infection levels was found in the ventral and dorsal regions in relation to other body parts (e.g., pectoral, pelvic and anal regions. Among the sampling points studied, we observed a higher prevalence on samples collected at points Gasômetro, Saco da Alemoa and Sinos, located in open areas with less occurrence of mollusks.

  2. Dieta de Astyanax asuncionensis (Characiformes, Characidae, em riachos da bacia do rio Cuiabá, Estado do Mato Grosso = Diet of Astyanax asuncionensis (Characiformes, Characidae, in streams of the Cuiabá river basin, Mato Grosso State

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    Cristina da Silva Borba

    2008-01-01

    Full Text Available A dieta de Astyanax asuncionensis, em riachos da bacia do rio Cuiabá, Estado do Mato Grosso, durante períodos de chuva e seca, foi descrita, sendo suas variações associadas ao grau de integridade da vegetação ciliar. Para isso, foram realizadas amostragens mensais,entre janeiro e dezembro de 2003, em quatro riachos, com o emprego de pesca elétrica. Foram analisados 213 estômagos, e a dieta foi descrita por meio das porcentagens de ocorrência e volume, combinados ao Índice Alimentar (IAi. Os aspectos da dieta abordadosconsistiram na composição, na origem dos recursos e na amplitude do nicho alimentar (Índice de Levins. O espectro alimentar incluiu 22 itens, sendo que os recursos alóctones dominaram, principalmente insetos, independente do local e período. A amplitude do nichoalimentar foi, em geral, maior no período de chuva. Os resultados obtidos mostraram que essas populações de A. asuncionensis são sustentadas por recursos de origem terrestre, especialmente Hymenoptera e demonstram a importância da mata ciliar no aporte dealimento. Considerando que os riachos apresentam diferentes graus de degradação da mata ciliar, estes resultados indicam que a manutenção da vegetação e a recuperação das áreas degradadas é condição altamente relevante para manutenção desta espécie nestes riachos.The goal of this study was to assess the diet of A. asuncionensis in four streams. Fish samples were carried out monthly from January to December 2003, using electrofishing. Stomach contents of 213 individuals were analyzed, and the diet was described as for occurrence and volumetric percentage of each item combined in a feeding index (IAi. The diet composition, importance of allochthonous and autochthonous resources, and diet breadth (Levin’s index were assessed among streams and between seasons (dry and rainy. The diet was composed of 22 feeding items; allochthonous resources (especially insects dominated the diet in all streams

  3. Mapping of the 18S and 5S ribosomal RNA genes in Astyanax altiparanae Garutti & Britski, 2000 (Teleostei, Characidae from the upper Paraná river basin, Brazil

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    Carlos Alexandre Fernandes

    2006-01-01

    Full Text Available Fluorescence in situ hybridization (FISH was undertaken in order to determinate the chromosomal distribution pattern of 18S and 5S ribosomal DNAs (rDNA in four populations of the characid fish Astyanax altiparanae from the upper Paraná river basin, Brazil. The 18S rDNA probe FISH revealed numerical and positional variations among specimens from the Keçaba stream compared to specimens of the other populations studied. In contrast to the variable 18S rDNA distribution pattern, highly stable chromosomal positioning of the 5S rDNA sites was observed in the four A. altiparanae populations. Divergence in the distribution pattern of 18S and 5S rDNA sites is also discussed.

  4. Albinism in phylogenetically and geographically distinct populations of Astyanax cavefish arises through the same loss-of-function Oca2 allele

    Science.gov (United States)

    Gross, J B; Wilkens, H

    2013-01-01

    The Mexican tetra, Astyanax mexicanus, comprises 29 populations of cave-adapted fish distributed across a vast karst region in northeastern Mexico. These populations have a complex evolutionary history, having descended from ‘old' and ‘young' ancestral surface-dwelling stocks that invaded the region ∼6.7 and ∼2.8 MYa, respectively. This study investigates a set of captive, pigmented Astyanax cavefish collected from the Micos cave locality in 1970, in which albinism appeared over the past two decades. We combined novel coloration analyses, coding sequence comparisons and mRNA expression level studies to investigate the origin of albinism in captive-bred Micos cavefish. We discovered that albino Micos cavefish harbor two copies of a loss-of-function ocular and cutaneous albinism type II (Oca2) allele previously identified in the geographically distant Pachón cave population. This result suggests that phylogenetically young Micos cavefish and phylogenetically old Pachón cave fish inherited this Oca2 allele from the ancestral surface-dwelling taxon. This likely resulted from the presence of the loss-of-function Oca2 haplotype in the ‘young' ancestral surface-dwelling stock that colonized the Micos cave and also introgressed into the ancient Pachón cave population. The appearance of albinism in captive Micos cavefish, caused by the same loss-of-function allele present in Pachón cavefish, implies that geographically and phylogenetically distinct cave populations can evolve the same troglomorphic phenotype from standing genetic variation present in the ancestral taxon. PMID:23572122

  5. Morphological and neurotoxicological findings in tropical freshwater fish (Astyanax sp.) after waterborne and acute exposure to water soluble fraction (WSF) of crude oil.

    Science.gov (United States)

    Akaishi, F M; de Assis, H C Silva; Jakobi, S C G; Eiras-Stofella, D R; St-Jean, S D; Courtenay, S C; Lima, E F; Wagener, A L R; Scofield, A L; Ribeiro, C A Oliveira

    2004-02-01

    The water-soluble fraction (WSF) of crude oil is a complex highly volatile and toxic mixture of hydrocarbon chains (polyaromatics, heterocyclics), phenols, and heterocyclic compounds containing nitrogen and sulfur. To evaluate the toxic effects of WSF in tropical freshwater teleosts and to develop methodologies that could investigate the toxic mechanisms of WSF in tropical organisms, an acute toxicity experiment was conducted with Astyanax sp. Three dilutions (15%, 33%, and 50%) of WSF obtained from Campos Bay's crude oil (Brazil) were used to study morphological and biochemical responses of the fish. Prior to exposure, the distribution and rate of volatilization of the WSF into each aquarium for the same exposure period was quantified by spectrofluorimetry. Five individuals of Astyvanax sp. were exposed to duplicate WSF of 0, 15, 33, and 50% for each of 12-, 24-, and 96-h exposures for a total of 120 individuals. Liver and gills were sampled from five fish from each treatment and were analyzed by histology, scanning and transmission electron microscopy. A fragment of muscle was also collected from each fish to measure acetylcholinesterase activity. Water analysis showed that only 4 h after dilution, an important loss of hydrocarbons in 33% and 50% of WSF was observed. In addition, 50% of hydrocarbon mass was lost in all tested dilutions after 24 h with significant difference for the 50% WSF at all measured times, demonstrating the high volatility of WSF in freshwater. Damage in the liver and the gills included the presence of necrosis, loss of hepatocytes limit, inflammation areas, cellular proliferation, aneurysms, and disorganization of the second lamellae. The 33% WSF significantly reduced acetylcholinesterase activity in fish. Our study demonstrated that the WSF of crude oil caused damage in organs and tissues of tropical freshwater Astyanax sp. and provided also the basis for a better understanding of the toxic mechanisms of WSF in freshwater fishes.

  6. Chromosomal mapping of H3 histone and 5S rRNA genes in eight species of Astyanax (Pisces, Characiformes) with different diploid numbers: syntenic conservation of repetitive genes.

    Science.gov (United States)

    Piscor, Diovani; Parise-Maltempi, Patricia Pasquali

    2016-03-01

    The genus Astyanax is widely distributed from the southern United States to northern Patagonia, Argentina. While cytogenetic studies have been performed for this genus, little is known about the histone gene families. The aim of this study was to examine the chromosomal relationships among the different species of Astyanax. The chromosomal locations of the 5S rRNA and H3 histone genes were determined in A. abramis, A. asuncionensis, A. altiparanae, A. bockmanni, A. eigenmanniorum, A. mexicanus (all 2n = 50), A. fasciatus (2n = 46), and A. schubarti (2n = 36). All eight species exhibited H3 histone clusters on two chromosome pairs. In six species (A. abramis, A. asuncionensis, A. altiparanae, A. bockmanni, A. eigenmanniorum, and A. fasciatus), syntenic clusters of H3 histone and 5S rDNA were observed on metacentric (m) or submetacentric (sm) chromosomes. In seven species, clusters of 5S rDNA sequences were located on one or two chromosome pairs. In A. mexicanus, 5S rDNA clusters were located on four chromosome pairs. This study demonstrates that H3 histone clusters are conserved on two chromosome pairs in the genus Astyanax, and specific chromosomal features may contribute to the genomic organization of the H3 histone and 5S rRNA genes.

  7. Population structure, reproductive biology and feeding of Astyanax fasciatus (Cuvier, 1819 in an Upper Paraná River tributary, Misiones, Argentina Estrutura populacional, biologia reprodutiva e alimentação de Astyanax fasciatus (Cuvier, 1819 em um tributário do alto Rio Paraná, Misiones, Argentina

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    Lourdes María Hirt

    2011-03-01

    Full Text Available AIM: The genus Astyanax is one of the richest in number of species and has one of the widest geographical distributions in Argentina, being possible to find in nine ichthyogeographic ecoregions. The aim of the present work was to analyze the population structure of Astyanax fasciatus in the Garupá Stream, Province of Misiones, Argentina, considering its distribution by size, standard length-total weight relationship and aspects of its reproductive and feeding biology; METHODS: A total of eight experimental fishing campaigns were carried out between September 2002 and May 2004, in agreement with the seasons of the year, using a set of gillnets; RESULTS: We captured a total of 386 individuals, 70% of which in the Middle Basin in autumn and winter. The following gonad stages were identified in both males and females: resting, maturing, mature and spawning. The highest gonadal activity corresponded to the autumn-winter period. The Middle Basin showed the highest capture of individuals in reproductive activity, thus reflecting the seasonality of spawning. The average fecundity was of 4000 oocytes, being 1100 µm the largest oocyte diameter. The mean standard length of the total catch was 99.3 mm and females reached larger sizes than males (P OBJETIVO: O gênero Astyanax é um dos mais ricos em número de espécies e tem uma das maiores distribuições geográficas na Argentina, sendo possível encontrar em nove ecorregiões ictiogeográfica. O objetivo do presente trabalho foi analisar a estrutura populacional de Astyanax fasciatus no arroio Garupá, Província de Misiones, na Argentina, considerando a sua distribuição por tamanho, relação peso-padrão de comprimento total e aspectos de sua biologia reprodutiva e alimentação; MÉTODOS: Foram realizadas oito operações de pescaria sazonais, entre setembro de 2002 e maio de 2004, com uma bateria de redes de emalhar; RESULTADOS: Foram capturados 386 indivíduos, 70% na Bacia Média no outono e

  8. Spatial, seasonal and ontogenetic variation in the diet of Astyanax aff. fasciatus (Ostariophysi: Characidae in an Atlantic Forest river, Southern Brazil

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    Luciano Lazzarini Wolff

    Full Text Available This study described the feeding habits of the characin Astyanax aff. fasciatus. The diet compositions of specimens from two sites (A and B on a river in Southern Brazil were compared according to the size of individuals and seasonal period. The collections were performed monthly from March 2005 to February 2006, where the stomach contents of 290 specimens were assessed. Food items for A. aff. fasciatus were basically composed of plants and insects, especially leaf fragments, seeds, fruits, filamentous algae, aquatic and terrestrial insects and insect fragments. At site A, the most common items were insect and plant fragments. Conversely at site B, plant fragments were more representative. In general, all items of animal origin showed the highest feeding index values at site A, whereas at site B detritus and grass items were more abundant. The composition of items varied seasonally, with higher diversity of items being recorded during the spring at both sites. Smaller individuals preferred items of animal origin, while the larger ones consumed mainly items of plant origin. According to its size, A. aff. fasciatus in this study may be considered a species with insectivorous tendencies when immature or herbivorous tendencies when adult. Nevertheless, its feeding habits may be flexible according to resource availability, showing wide ontogenetic, besides spatial and temporal variation.

  9. A new species of Henneguya, a gill parasite of Astyanax altiparanae (Pisces: Characidae from Brazil, with comments on histopathology and seasonality

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    Barassa Bianca

    2003-01-01

    Full Text Available A new species of Myxosporea, Henneguya chydadea, is described parasitizing the gills of Astyanax altiparanae collected from a lake on Rio das Pedras farm near Campinas, state of São Paulo, Brazil. Of the fish examined, 88.3% had gills parasitized by myxosporeans. The prevalence of the parasite ranged from 80% in the spring and fall, 93% in the summer and 100% in the winter. The parasite induced the formation of white, oval-shaped cysts measuring 40-64 µm x 64-80 µm which deformed the gill lamellae, compressed the capillaries, and caused retraction of the neighboring lamellae. The mature spores were elongated and had two identical, parallel elongate polar capsules. Each capsule contained a polar filament with 9-10 turns. There was no mucous envelope or iodinophilous vacuole. Morphometric differences between this parasite and other species of the genus Henneguya indicated, that he parasite observed in A. altiparanae is a new species. This is the first report of a myxosporeanparasitizing A. altiparanae.

  10. Quantifying structural modifications of gills of two fish species Astyanax altiparanae (Lambari) and Prochilodus lineatus (Curimbatá) after exposure to biodegradable detergents in urban lake water.

    Science.gov (United States)

    Fiorelini Pereira, Bruno; Alves, Anderson Luis; Senhorini, José Augusto; Hakime Scalize, Priscilla; Tocchini De Figueiredo, Fellipe Augusto; Pitol, Dimítrius Leonardo; Caetano, Flávio Henrique

    2017-01-01

    Anthropic actions in rivers and urban lakes are a cause for concern to our ecosystem. The effects on fauna and flora of substances discharged into waterways have become a focus for investigations globally. Biodegradable detergents are widely used in residences and small industries, but little is known regarding the consequences on fish fauna. The objective of the present study was to identify modifications in gill structure in two fish species, Astyanax altiparanae and Prochilodus lineatus, after treatment with water obtained from an urban lake and an exposure to 1 ppm diluted biodegradable detergents (linear alkylbenzene sulfonate). Data demonstrated exposure to urban lake produced various alterations in gill functions such as lamellar fusions, aneurysms, mucous, and chlorine cell proliferation, which may be attributed to the presence of detergents in the water but may also be a consequence of synergetic actions of detergents with other pollutants. Results showed that the levels of NO(-)2, Na, F(-), Cl(-), and Fe were significantly higher in urban lake water but in the presence of detergents Ni was also detected. Evidence indicates that biodegradable detergents produce damage to gill functions, which subsequently alters the fish physiology and reduces the ability to cope with stress and survival.

  11. Delimiting the origin of a B chromosome by FISH mapping, chromosome painting and DNA sequence analysis in Astyanax paranae (Teleostei, Characiformes.

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    Duílio M Z de A Silva

    Full Text Available Supernumerary (B chromosomes have been shown to contain a wide variety of repetitive sequences. For this reason, fluorescent in situ hybridisation (FISH is a useful tool for ascertaining the origin of these genomic elements, especially when combined with painting from microdissected B chromosomes. In order to investigate the origin of B chromosomes in the fish species Astyanax paranae, these two approaches were used along with PCR amplification of specific DNA sequences obtained from the B chromosomes and its comparison with those residing in the A chromosomes. Remarkably, chromosome painting with the one-arm metacentric B chromosome probe showed hybridization signals on entire B chromosome, while FISH mapping revealed the presence of H1 histone and 18S rDNA genes symmetrically placed in both arms of the B chromosome. These results support the hypothesis that the B chromosome of A. paranae is an isochromosome. Additionally, the chromosome pairs Nos. 2 or 23 are considered the possible B chromosome ancestors since both contain syntenic H1 and 18S rRNA sequences. The analysis of DNA sequence fragments of the histone and rRNA genes obtained from the microdissected B chromosomes showed high similarity with those obtained from 0B individuals, which supports the intraspecific origin of B chromosomes in A. paranae. Finally, the population hereby analysed showed a female-biased B chromosome presence suggesting that B chromosomes in this species could influence sex determinism.

  12. IMPACTS OF FISH FARM DAMS ON TEMPORAL AND SPATIAL DISTRIBUTION OF Astyanax cf. bimaculatus IN MICROBASINS OF THE MACHADO RIVER (RONDÔNIA, BRAZIL

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    Marcos de Almeida Mereles

    2017-06-01

    Full Text Available The present study evaluated the effects of fish farm dams on spatial and temporal distribution of lambari Astyanax cf. bimaculatus in five headwater streams of the Machado River basin, Rondônia State, Brazil. The results show that fish farm dams are spatially separating wild lambari populations into upstream and downstream groups. Moreover, it was observed that the dry and rainy seasons influence the abundance and presence of A. cf. bimaculatus in these areas, while limnological parameters did not differ y in the streams. Additionally, it was shown that fish farm dams built in the headwater stream areas impede the migratory routes of A. bimaculatus, and also possibly the local movements of resident fish populations. Therefore, before the implementation of new farm dams using natural streams in the future, mitigation plans should include adequate access routes for fish to travel between upstream and downstream areas, in order to avoid adversely affecting their wild populations. Keywords: Fish farm dams; lambari fish; Madeira River; microbasins; population parameters.

  13. Gill histopathology and micronucleus test of Astyanax jacuhiensis (Cope, 1894 (Teleostei, Characidae to evaluate effects caused by acute exposure to aluminum

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    Thaís Dalzochio

    2016-02-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2016v29n1p75 The contamination of aquatic environments by aluminum (Al is usually caused by several anthropogenic activities. Diverse morphological, physiological and biochemical alterations in aquatic organisms have been attributed to exposure to Al. In this context, the aim of this study was to investigate the effects of acute exposure to different concentrations of Al on the histology of gills and frequency of micronucleus (MN and nuclear abnormalities (NA in erythrocytes of the fish Astyanax jacuhiensis. Fish were exposed to sublethal concentrations of 0.3 mg/L and 30 mg/L of aluminum at neutral pH for 72 h. A control group was kept in filtrated water. The alterations in the gills were characterized by epithelial hyperplasia and hypertrophy, lamellar fusion, edema, epithelial lifting, aneurism and necrosis. A significant increase (p<0.05 in the frequency of abnormal lamellae was observed in groups exposed to both concentrations of Al in comparison with the control group. On the other hand, no statistical differences were observed in the frequencies of MN and NA. Although no evidence of genotoxicity was observed, the results found in the gill morphological analysis suggest that Al was toxic to the fish at both concentrations tested under neutral pH.

  14. Determination of growth curve throwgh scales lecture in different body regions of Astyanax bimaculatus (Linnaeus, 1758 (Pisces, Characidae, in Ibitinga reservoir, São Paulo State

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    Maria Teresa Duarte Giamas

    1992-12-01

    Full Text Available Com o objetivo de determinar a curva de crescimento segundo a expressão de von Bertalanffy, referente à espécie Astyanax bimaculatus presente na Represa de Ibitinga (21°46’S e 48°59’, foi empregado o método de contagem dos anéis etários de escamas. Para a extração destas estruturas, foi também identificada dentre seis áreas, a mais adequada do corpo, quanto à precisão de leitura, segundo WERDER e SOARES18 (1984. Foram examinados 50 exemplares, amostrados no período de julho de 1989 a junho de 1990. Observaram-se 8 classes etárias, e os comprimentos totais médios de 1 a 8 anos foram, respectivamente: 61,03 mm: 75,30 mm; 86,67 mm; 97,92  mm; 109,80 mm; 121,75 mm; 134,13 mm e 144,40 mm. A curva de crescimento determinada foi: ^Lt = 223,14 [1 – e -0,1027 (t + 1,8549

  15. Ocorrência e ecologia trófica de quatro espécies de Astyanax (Characidae) em diferentes rios da bacia do rio Tibagi, Paraná, Brasil

    OpenAIRE

    Sirlei Terezinha Bennemann; Ana Maria Gealh; Mário Luís Orsi; Leda Maria de Souza

    2005-01-01

    Na bacia do rio Tibagi, trechos dos rios Fortaleza, Iapó e Tibagi foram amostrados mensalmente, de maio de 2001 a abril de 2002, com tarrafas e redes de espera de diferentes malhagens. Foram capturados indivíduos de quatro espécies de Astyanax. Para conhecer como essas espécies utilizam o hábitat desses rios, foi calculada a constância, e as freqüências em número de exemplares foram comparadas pela análise de similaridade Bray-Curtis. A composição percentual dos alimentos consumidos foi orden...

  16. Use of cholinesterase activity as a biomarker of pesticide exposure used on Costa Rican banana plantations in the native tropical fish Astyanax aeneus (Günther, 1860).

    Science.gov (United States)

    Mena, F; Azzopardi, M; Pfennig, S; Ruepert, C; Tedengren, M; Castillo, L E; Gunnarsson, J S

    2014-01-01

    In Costa Rica, thousands of tones of agricultural pesticides have been used for decades and their use is continuously increasing due to intensive and expanding production of coffee, pineapple, rice, ornamental plants and bananas. The objective of this study was to evaluate whether choline esterase (ChE) activity could be used as a biomarker of exposure to pesticides in the Costa Rican native fish Astyanax aeneus (characidae). Three methods used in order to evaluate the ChE biomarker were as follows: Laboratory studies where A. aeneus was exposed to organophosphate pesticide (ethoprophos); In situ 48 hr exposure assessment using caging experiments with fish exposed upstream and downstream of banana plantations and ChE activity estimation of in fish captured directly at sites with different degrees of pesticide exposure. Results from the laboratory studies showed that ChE activity in both brain and muscle tissue was significantly lower in fish exposed to ethoprophos than in controls. Fish from the caging experiments showed no difference in ChE activity neither in brain nor in muscle tissue between the four tested sites and was attributed to the short duration of the exposure. Asignificant difference in ChE activity was determined in muscle of fish captured from Laguna Madre de Dios compared to fish from Canal Batán. Although our laboratory results revealed that ChE activity in A. aeneus was highly responsive to ethoprophos, results from field experiments were less conclusive and showed that the captured fish showed large variability in ChE activity and that more research is needed before ChE activity can be used as reliable biomarker of pesticide exposure.

  17. A novel role for Mc1r in the parallel evolution of depigmentation in independent populations of the cavefish Astyanax mexicanus.

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    Joshua B Gross

    2009-01-01

    Full Text Available The evolution of degenerate characteristics remains a poorly understood phenomenon. Only recently has the identification of mutations underlying regressive phenotypes become accessible through the use of genetic analyses. Focusing on the Mexican cave tetra Astyanax mexicanus, we describe, here, an analysis of the brown mutation, which was first described in the literature nearly 40 years ago. This phenotype causes reduced melanin content, decreased melanophore number, and brownish eyes in convergent cave forms of A. mexicanus. Crosses demonstrate non-complementation of the brown phenotype in F(2 individuals derived from two independent cave populations: Pachón and the linked Yerbaniz and Japonés caves, indicating the same locus is responsible for reduced pigmentation in these fish. While the brown mutant phenotype arose prior to the fixation of albinism in Pachón cave individuals, it is unclear whether the brown mutation arose before or after the fixation of albinism in the linked Yerbaniz/Japonés caves. Using a QTL approach combined with sequence and functional analyses, we have discovered that two distinct genetic alterations in the coding sequence of the gene Mc1r cause reduced pigmentation associated with the brown mutant phenotype in these caves. Our analysis identifies a novel role for Mc1r in the evolution of degenerative phenotypes in blind Mexican cavefish. Further, the brown phenotype has arisen independently in geographically separate caves, mediated through different mutations of the same gene. This example of parallelism indicates that certain genes are frequent targets of mutation in the repeated evolution of regressive phenotypes in cave-adapted species.

  18. Controle alternativo de helmintos de Astyanax cf. zonatus utilizando fitoterapia com sementes de abóbora (Cucurbita maxima e mamão (Carica papaya

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    Rodrigo Y. Fujimoto

    2012-01-01

    Full Text Available O objetivo do trabalho foi avaliar a eficácia de sementes de abóbora e mamão desidratadas e moídas, no controle de helmintos parasitos de Astyanax cf. zonatus. Sessenta peixes foram distribuídos em doze recipientes, um peixe/litro. O experimento constituiu de quatro tratamentos e três repetições: TJ = peixes deixados em jejum; TRC = peixes alimentados com ração comercial; TSA = peixes alimentados ad libitum com abóbora, e TSM = peixes alimentados ad libitum com mamão. Após sete dias de alimentação, todos os peixes foram pesados, e o sangue foi retirado para extensão sanguínea. A eficácia foi determinada, verificando a presença de parasitos nas brânquias, no estômago e no intestino. Os peixes do TJ e TSM apresentaram perda de peso (39% e 25%, respectivamente. O TSA apresentou melhor eficácia no controle de nematóides do intestino e do estômago (95,26% e 92,48%. No controle de monogenéticos TSM promoveu 72% de eficácia. Na hematologia observou-se aumento de monócitos nos peixes do TSM e os valores de eosinofilos diminuíram nos tratamentos TSA, TSM e TRC. Assim pode-se concluir que a alimentação com abóbora pode ser utilizado como um controle alternativo eficaz de nematóides intestinais do lambari.

  19. Oxidative stress markers in fish (Astyanax sp. and Danio rerio) exposed to urban and agricultural effluents in the Brazilian Pampa biome.

    Science.gov (United States)

    Costa-Silva, D G; Nunes, M E M; Wallau, G L; Martins, I K; Zemolin, A P P; Cruz, L C; Rodrigues, N R; Lopes, A R; Posser, T; Franco, J L

    2015-10-01

    Aquatic ecosystems are under constant risk due to industrial, agricultural, and urban activities, compromising water quality and preservation of aquatic biota. The assessment of toxicological impacts caused by pollutants to aquatic environment using biomarker measurements in fish can provide reliable data to estimate sublethal effects posed by chemicals in contaminated areas. In this study, fish (Astyanax sp. and Danio rerio) exposed to agricultural and urban effluents at the Vacacaí River, Brazil, were tested for potential signs of aquatic contamination. This river comprehends one of the main watercourses of the Brazilian Pampa, a biome with a large biodiversity that has been neglected in terms of environmental and social-economic development. Sites S1 and S2 were chosen by their proximity to crops and wastewater discharge points, while reference site was located upstream of S1 and S2, in an apparently non-degraded area. Fish muscle and brain tissues were processed for determination of acetylcholinesterase as well as oxidative stress-related biomarkers. The results showed signs of environmental contamination, hallmarked by significant changes in cholinesterase activity, expression of metallothionein, antioxidant enzymes, glutathione levels, and activation of antioxidant/cell stress response signaling pathways in fish exposed to contaminated sites when compared to reference. Based on these results, it is evidenced that urban and agricultural activities are posing risk to the environmental quality of water resources at the studied area. It is also demonstrated that cell stress biomarkers may serve as important tools for biomonitoring and development of risk assessment protocols in the Pampa biome.

  20. Atividades de lactato desidrogenase e malato desidrogenase de Astyanax bimaculatus (lambari da bacia hidrográfica do rio Una como biomarcadoras de impacto ambiental

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    Anne Caroline Ribeiro

    2015-11-01

    Full Text Available Os peixes vivem todo o ciclo de vida na água e recebem a influência dos seus componentes físico-químicos e biológicos ao longo do tempo. As atividades de lactato desidrogenase (LDH e malato desidrogenase (MDH de organismos aquáticos podem ser alteradas devido à presença de poluentes na água. O objetivo deste estudo foi determinar se as atividades de LDH e MDH nas brânquias e no fígado de Astyanax bimaculatus (lambari do rabo amarelo podem ser utilizadas como biomarcadoras do impacto ambiental na bacia hidrográfica do rio Una (SP. Para isso, esses lambaris foram coletados em três corpos d’água dessa bacia, denominados p1 (rio Itaim, p2 (córrego à beira da Estrada Municipal de Remédios e p3 (lago na Estrada Municipal Dr. José Luiz Cembranelli. As brânquias e o fígado foram homogeneizados e, a seguir, esse material foi centrifugado e o sobrenadante foi utilizado para determinação das atividades de LDH e MDH, através do método espectrofotométrico que determina a taxa de oxidação de NADH. As atividades de LDH e MDH no fígado e de MDH branquial não foram estatisticamente diferentes nos lambaris coletados nos três locais. No tecido branquial a atividade de LDH foi inferior nos peixes de p3 em relação aos de p1. Essa inibição da atividade de LDH, bem como a qualidade inferior da água nesse ponto, sugerem a ocorrência de poluentes nessa água. Conclui-se que LDH branquial de lambari possui potencial para utilização como marcador bioquímico de impacto ambiental no rio Una.

  1. A multi-approach analysis of the genetic diversity in populations of Astyanax aff. bimaculatus Linnaeus, 1758 (Teleostei: Characidae from Northeastern Brazil

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    Vanessa de Carvalho Cayres Pamponet

    Full Text Available Few reports are available about the ichthyofauna of typical semi-arid rivers, although the regional diversity has been constantly threatened by human activities, mainly related to impoundment and construction of dams. The goal of the present work was to evaluate using different methods, the population genetic structure of a characin fish, Astyanax aff. bimaculatus, widespread throughout hydrographic basins of Bahia, Northeastern Brazil. Morphological (meristic and morphometric data, cytogenetic (karyotype and Ag-NOR, and molecular (RAPD and SPAR analyses were carried out in specimens collected upstream and downstream of Pedra Dam, in the main channel of Contas River (Contas River Basin, and in the Mineiro stream, which belongs to the adjacent Recôncavo Sul basin. Few external differences were detected among populations, where the individuals collected upstream of Pedra Dam were slightly larger than the others. Cytogenetic data also showed a similar karyotypic pattern (2n=50; 6m+28sm+12st+4a; FN= 96 and NORs located on the short arms of up to two chromosome pairs, with numerical inter- and intra-populational variation. Nonetheless, RAPD and SPAR analyses differentiated reliably the three populations, revealing striking differences in the allele frequencies among the localities studied and a significant difference in population structure index (Fst=0.1868, P<0.0001. The differences between populations within a same river were as significant as those between distinct hydrographic basins, indicating that the dam/reservoir represents an effective barrier to gene flow. Additionally, environmental peculiarities from each locality are also believed to influence the genetic patterns detected herein. On the other hand, the similarity between samples from Contas River and Recôncavo Sul basins could be related to a common evolutionary history, since both basins are geographically close to each other. Finally, the present study shows that a multi

  2. A new species of Auriculostoma (Digenea: Allocreadiidae) in the Mexican tetra Astyanax mexicanus (Actinopterygii: Characidae) from Central Veracruz, Mexico, described with the use of morphological and molecular data.

    Science.gov (United States)

    Razo-Mendivil, Ulises; Mendoza-Garfias, Berenit; de León, Gerardo Pérez-Ponce; Rubio-Godoy, Miguel

    2014-06-01

    Auriculostoma totonacapanensis n. sp. is described from the Mexican tetra, Astyanax mexicanus (Actinopterygii, Characidae) collected in a tributary creek of the Bobos River in Filipinas, Veracruz, Mexico. The new species is set apart from all congeners by the combination of some morphological characters such as the testes position (oblique in most specimens), the ventral to oral sucker ratio (1:1.2 × 1:1.1), the cirrus sac originating at the ovarian region, and by having vitelline follicles not confluent in the posttesticular region. Auriculostoma totonacapanensis n. sp. closely resembles Auriculostoma platense (Szidat, 1954) Scholz, Aguirre-Macedo, and Choudhury, 2004 and Auriculostoma diagonale Curran, Tkach and Overstreet, 2011 by possessing oblique testes; however, it differs from both species by possessing a genital pore located at level of the cecal bifurcation and by having vitelline follicles extending anteriorly up to the cecal bifurcation level, instead of a genital pore located between the anterior margin of the ventral sucker and cecal bifurcation, and vitelline follicles extending anteriorly to the mid level of the esophagus as in A. platense or to the pharynx level as in A. diagonale. Additionally, the new species differs from A. diagonale by having vitelline follicles not confluent or scarcely confluent in the posttesticular region rather than extensively confluent. Scanning electron microscopy micrographs of the new species demonstrated the presence of a single pair of muscular lobes on either side of the oral sucker, with a broad base, stretching from the ventrolateral to the dorsolateral side. Maximum parsimony and Bayesian inference analyses of the 28S rRNA gene sequences placed A. totonacapanensis as sister species of Auriculostoma astyanace Scholz, Aguirre-Macedo, and Choudhury, 2004 . Nucleotide variation between A. totonacapanensis and A. astyanace was 2.0% and 3.6% for the 28S rRNA gene and ITS2 sequences, respectively. Sequence variation

  3. Reproductive biomarkers responses induced by xenoestrogens in the characid fish Astyanax fasciatus inhabiting a South American reservoir: An integrated field and laboratory approach

    Energy Technology Data Exchange (ETDEWEB)

    Prado, Paula S.; Pinheiro, Ana Paula B. [Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, UFMG, Belo Horizonte, C.P. 486, 30161-970, Minas Gerais (Brazil); Bazzoli, Nilo [Programa de Pós-Graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais, PUC Minas, Belo Horizonte 30535-610, Minas Gerais (Brazil); Rizzo, Elizete, E-mail: ictio@icb.ufmg.br [Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, UFMG, Belo Horizonte, C.P. 486, 30161-970, Minas Gerais (Brazil)

    2014-05-01

    Field studies evaluating the effects of endocrine disruption chemicals (EDCs) on the fish reproduction are scarce worldwide. The goal of this study was to assess hepatic levels of vitellogenin (Vtg), zona radiata proteins (Zrp) and insulin-like growth factors (IGF-I and IGF-II), and relating them to reproductive endpoints in a wild fish population habiting a reservoir that receive domestic sewage, agricultural and industrial residues. Adult fish Astyanax fasciatus were sampled during the reproductive season in five sites from the Furnas Reservoir, Grande River, and Paraguay–Paraná basin. As a control to field data, fish were experimentally exposed via dietary intake, to oestradiol benzoate (OB) for 7 days. Fish from site with little anthropogenic interference showed hepatic levels of Vtg, Zrp and IGF-I and IGF-II similar to those from the non-treated experimental group. In sites located immediately downstream from the municipal wastewater discharges, the water total oestrogen was >120 ng/l, and male fish displayed increased Vtg and Zrp and decreased IGF-I levels similar to OB treated fish. In females, levels of Vtg, Zrp, IGF-I and IGF-II suggest an impairment of final oocyte maturation and spawning, as also detected by frequency of over-ripening, follicular atresia and fecundity. At the sites that receive agricultural and industrial residues, the water total oestrogen was <50 ng/l and females showed decreased Zrp and increased IGF-II levels associated to reduced diameter of vitellogenic follicles, indicating an inhibition of oocyte growth. Overall, the current study reports oestrogenic contamination impairing the reproduction of a wild fish from a hydroeletric reservoir and, the data contribute to improving the current knowledge on relationship between hepatic Vtg, Zrp and IGF-I and IGF-II, and reproductive endpoints in a teleost fish. In addition, our data point out novel reproductive biomarkers (IGF-I, IGF-II and over-ripening) to assessing xenoestrogenic

  4. Dieta de Astyanax asuncionensis (Characiformes, Characidae, em riachos da bacia do rio Cuiabá, Estado do Mato Grosso - DOI: 10.4025/actascibiolsci.v30i1.1442 Diet of Astyanax asuncionensis (Characiformes, Characidae, in streams of the Cuiabá river basin, Mato Grosso State - DOI: 10.4025/actascibiolsci.v30i1.1442

    Directory of Open Access Journals (Sweden)

    Gisele Caroline Novakowski

    2008-03-01

    Full Text Available A dieta de Astyanax asuncionensis, em riachos da bacia do rio Cuiabá, Estado do Mato Grosso, durante períodos de chuva e seca, foi descrita, sendo suas variações associadas ao grau de integridade da vegetação ciliar. Para isso, foram realizadas amostragens mensais, entre janeiro e dezembro de 2003, em quatro riachos, com o emprego de pesca elétrica. Foram analisados 213 estômagos, e a dieta foi descrita por meio das porcentagens de ocorrência e volume, combinados ao Índice Alimentar (IAi. Os aspectos da dieta abordados consistiram na composição, na origem dos recursos e na amplitude do nicho alimentar (Índice de Levins. O espectro alimentar incluiu 22 itens, sendo que os recursos alóctones dominaram, principalmente insetos, independente do local e período. A amplitude do nicho alimentar foi, em geral, maior no período de chuva. Os resultados obtidos mostraram que essas populações de A. asuncionensis são sustentadas por recursos de origem terrestre, especialmente Hymenoptera e demonstram a importância da mata ciliar no aporte de alimento. Considerando que os riachos apresentam diferentes graus de degradação da mata ciliar, estes resultados indicam que a manutenção da vegetação e a recuperação das áreas degradadas é condição altamente relevante para manutenção desta espécie nestes riachosThe goal of this study was to assess the diet of A. asuncionensis in four streams. Fish samples were carried out monthly from January to December 2003, using electrofishing. Stomach contents of 213 individuals were analyzed, and the diet was described as for occurrence and volumetric percentage of each item combined in a feeding index (IAi. The diet composition, importance of allochthonous and autochthonous resources, and diet breadth (Levin’s index were assessed among streams and between seasons (dry and rainy. The diet was composed of 22 feeding items; allochthonous resources (especially insects dominated the diet in all

  5. Feeding and morphological analysis of the digestive tract of four species of fish (Astyanax altiparanae, Parauchenipterus galeatus, Serrasalmus marginatus and Hoplias aff. malabaricus from the upper Paraná River floodplain, Brazil

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    D. Peretti

    Full Text Available The present study is inspired by the great wealth of species exhibited by the ichthiofauna. Not only concepts and techniques of ecology deserve attention, but also knowledge in other biological areas, such as zoology and anatomy, are necessary. The intention of the present work is to discover the morphology of fish through the study of the digestive tract morphology, associating it to diet data, in order to better understand the biology of four fish species of the upper Paraná River floodplain. The samples were collected quarterly in the year 2000 with gillnets of different meshes. The stomach content was analyzed under a stereoscopic microscope and the frequencies of occurrence (FO and volumetric (FV and the alimentary index (IAi were calculated. Various morphologic characteristics were analyzed and schematized using a light chamber. The species were grouped into two trophic guilds - insectivores (Astyanax altiparanae and Parauchenipterus galeatus and piscivores (Serrasalmus marginatus and Hoplias aff. malabaricus. The first two, although consumers of insects, preyed on different alimentary groups, notably Hymenoptera in the case of A. altiparanae and Coleoptera in the case of P. galeatus. Serrasalmus marginatus and H. aff. malabaricus consumed mainly fishes. However, only pieces of prey were usually found in the stomach content of the first species, whereas whole fishes were found in the stomach content of the second. Astyanax altiparanae exhibited characteristics that allowed it to obtain food in several compartments of the water column. Similarly P. galeatus consumed food resources that were available in all aquatic compartments, although the abilities to capture, to manipulate and to absorb food differed, as shown by the importance of teeth plates and pharyngeal teeth. Serrasalmus marginatus and H. aff. malabaricus, although resembling each other in many aspects of the digestive tract morphology, differed in the strategies used to capture

  6. Ichthyofauna from the Emas National Park region: composition and structure

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    E. Benedito-Cecilio

    Full Text Available The relationship between habitats and the ichthyofauna composition in the Parque Nacional das Emas (PNE and adjacent areas (the Araguaia and Sucuriú rivers are provided and could be applied in determining the Park's future zoning. Samples of the ichthyofauna and limnological parameters were obtained during both dry (September 1999 and wet (December 1999 seasons. Ichthyofauna collections resulted in the capture of 4,740 specimens of 22 species. The most abundant species in the Araguaia River during the two sampling seasons were Astyanax sp. 2 and Hasemania sp. In the Sucuriú River and PNE, Astyanax scabripinnis cf. paranae and Hoplias aff. malabaricus were the most frequent species. The largest number of species and diversity index were recorded for the Araguaia River. However, sound management policies require more detailed studies on the fish communities of the Cerrado biome.

  7. Reproductive traits and population structure of Astyanax aeneus (Characiformes: Characidae from a subtropical river in Mexico Rasgos reproductivos y estructura de la población de Astyanax aeneus (Characiformes: Characidae de un río subtropical en México

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    Patricia Trujillo-Jiménez

    2013-06-01

    Full Text Available Champotón River is an unknown area within the Mesoamerican hotspot in Southestern México. Reproductive traits and population structure of Astyanax aeneus were analyzed along an environmental gradient of the upper, middle and lower sections of the river, where diverse environmental factors were recorded. For this, nets were cast for 1h at each site and A. aeneus were collected from all sections with sweep nets (5 and 10m long by 5m deep, 0.03m mesh size and a casting net (0.05m mesh size. At each study site and campaign, a total of 80 specimens (in average were collected and were fixed in 10% formaldehyde for further analysis. Population structure by size was analyzed for each study site, based on the relative frequencies by standard length classes. The length-weight relationship was determined, and the identification of gonadal developmental stages, reproductive period, size at first sexual maturity, relative fecundity, sex ratio and somatic indexes (gonadosomatic, hepatosomatic and Fulton’s condition factor were also assessed. Seven size classes were found in the upper and middle sections, and nine downstream, with seasonal and spatial pattern in size-class frequency distribution. Size at first maturity was 45.7mm for females and 40.8mm for males. The maximum relative fecundity was recorded at the downstream site and was positively correlated with body weight and standard length. Sex ratio (1.8:1 males: females differed significantly from expected values (1:1. Gonadosomatic index scores indicated that the reproductive period of this species in the Champotón River was from April to July, during the warm and wet season. Hepatosomatic index was negatively correlated with the Gonadosomatic index, evidencing transfer of energy from the liver towards gamete production. This strategy enabled A. aeneus to maintain robustness during the study period with tiny changes in condition factor. A. aeneus in the Champotón River, as opposed to South

  8. Phylogeography in Galaxias maculatus (Jenyns, 1848) along Two Biogeographical Provinces in the Chilean Coast

    Science.gov (United States)

    González-Wevar, Claudio A.; Salinas, Pilar; Hüne, Mathias; Segovia, Nicolás I.; Vargas-Chacoff, Luis; Astorga, Marcela; Cañete, Juan I.; Poulin, Elie

    2015-01-01

    Major geologic and climatic changes during the Quaternary exerted a major role in shaping past and contemporary distribution of genetic diversity and structure of aquatic organisms in southern South America. In fact, the northern glacial limit along the Pacific coast, an area of major environmental changes in terms of topography, currents, and water salinity, represents a major biogeographic transition for marine and freshwater species. We used mitochondrial DNA sequences (D-loop) to investigate the consequences of Quaternary glacial cycles over the pattern of genetic diversity and structure of G. maculatus (Pisces: Galaxiidae) along two biogeographical provinces in the Chilean coast. Extreme levels of genetic diversity and strong phylogeographic structure characterize the species suggesting a low amount of influence of the last glacial cycle over its demography. However, we recognized contrasting patterns of genetic diversity and structure between main biogeographical areas here analyzed. Along the Intermediate Area (38°–41° S) each estuarine population constitutes a different unit. In contrast, Magellanic populations (43°–53° S) exhibited low levels of genetic differentiation. Contrasting patterns of genetic diversity and structure recorded in the species between the analyzed biogeographic areas are consistent with the marked differences in abiotic factors (i.e., different coastal configurations, Quaternary glacial histories, and oceanographic regimes) and to inherent characteristics of the species (i.e., salt-tolerance, physiology, and reproductive behavior). PMID:26161896

  9. Efecto de la salinidad en la supervivencia embrionaria de puye Galaxias maculatus (Jenyns, 1842

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    Juan Barile

    2015-05-01

    Full Text Available Se evaluó e l efecto de la salinidad en la supervivencia embrionaria, período embrionario y período de eclosión de puye, Galaxias maculatus. Se utilizaron ocho tratamientos, con salinidades de 0, 4, 8, 12, 16 y 20 obteniéndose supervivencias embrionarias promedios respectivas de 84,9; 84,0; 85,5; 86,1; 82,6 y 75,8%, sin diferencias significativas entre ellas, mientras que con salinidad de 24 se obtuvo sobrevivencia de 10,4%, significativamente diferente al resto de los tratamientos y con salinidad de 28 causó 100% de mortalidad. A diferencia del estado juvenil y adulto, el embrión es incapaz de resistir la salinidad marina y su umbral de tolerancia se encuentra entre salinidades de 24 y 28. Las mayores supervivencias promedios larvales a 10 días de vida fueron con salinidades intermedias de 8, 12 y 16 de 79,3; 80,3 y 74,6% respectivamente, sin diferencias significativas entre ellas, demostrando alta viabilidad del embrión post-eclosión. Los períodos embrionarios promedios (50% más breves fueron a bajas salinidades 0, 4, 8, 12 con 28,7; 28,0; 29,7 y 29,7 días y los más extensos en los tratamientos con salinidades de 16 y 20, con 34,0 y 34,3 días, sin diferencias significativas entre ellos. Los períodos de eclosión promedio (50% con salinidades de 0, 4, 8, 12, 16, 20 y 24 fueron de 5,0; 5,5; 7,5; 8,8; 13,0; 14,3 y 15,8 días respectivamente, sin diferencias significativas entre ellos.

  10. Isolation Driven Divergence in Osmoregulation in Galaxias maculatus (Jenyns, 1848 (Actinopterygii: Osmeriformes.

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    Ignacio Ruiz-Jarabo

    Full Text Available Marine species have colonized extreme environments during evolution such as freshwater habitats. The amphidromous teleost fish, Galaxias maculatus is found mainly migrating between estuaries and rivers, but some landlocked populations have been described in lakes formed during the last deglaciation process in the Andes. In the present study we use mtDNA sequences to reconstruct the historical scenario of colonization of such a lake and evaluated the osmoregulatory shift associated to changes in habitat and life cycle between amphidromous and landlocked populations.Standard diversity indices including the average number of nucleotide differences (Π and the haplotype diversity index (H indicated that both populations were, as expected, genetically distinctive, being the landlocked population less diverse than the diadromous one. Similarly, pairwise GST and NST comparison detected statistically significant differences between both populations, while genealogy of haplotypes evidenced a recent founder effect from the diadromous stock, followed by an expansion process in the lake. To test for physiological differences, individuals of both populations were challenged with a range of salinities from 0 to 30 ppt for 8 days following a period of progressive acclimation. The results showed that the landlocked population had a surprisingly wider tolerance to salinity, as landlocked fish survival was 100% from 0 to 20 ppt, whereas diadromous fish survival was 100% only from 10 to 15 ppt. The activity of ATPase enzymes, including Na+/K+-ATPase (NKA, and H+-ATPase (HA was measured in gills and intestine. Activity differences were detected between the populations at the lowest salinities, including differences in ATPases other than NKA and HA. Population differences in mortality are not reflected in enzyme activity differences, suggesting divergence in other processes.These results clearly demonstrate the striking adaptive changes of G. maculatus osmoregulatory system, especially at hyposmotic environments, associated to a drastic shift in habitat and life cycle at a scale of a few thousand years.

  11. Distribuição de peixes na microbacia do Ribeirão Grande, Serra da Mantiqueira Oriental, São Paulo, Brasil Fish distribution in the Ribeirão Grande Basin, Eastern Serra da Mantiqueira, São Paulo, Brazil

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    Francisco Manoel de Souza Braga

    Full Text Available Foram amostrados oito pontos de coleta no sistema do Ribeirão Grande (22º47'08"S, 45º28'17"W, de julho de 2001 a abril de 2002. Os peixes foram amostrados quatro vezes em cada ponto, no inverno (julho de 2001, na primavera (outubro de 2001, no verão (fevereiro de 2002 e no outono (abril de 2002. Em cada ponto obteve-se a condutividade, pH, temperatura da água e oxigênio dissolvido, a elevação foi obtida em metros utilizando-se de um receptor GPS. A dimensão da distribuição espacial foi a principal fonte de variabilidade na distribuição de peixes no sistema do Ribeirão Grande. Foi capturado um total de 37 espécies e as dez espécies mais abundantes correspondem a quase 90% do total capturado. Pareiorhina rudolphi foi capturada principalmente na encosta; Characidium lauroi, Trichomycterus itatiayae, Neoplecostomus microps, Astyanax scabripinnis, Taunaya bifasciata e Harttia carvalhoi foram capturadas no pediplano; Characidium alipioi, Imparfinis minutus e Loricariichthys sp. foram capturadas na planície do vale. Os pontos amostrais P6 e P7, localizados na transição entre tributários e o canal principal, foram considerados um ecótono, onde a diversidade de espécies foi mais alta.Eight sites were surveyed in the Ribeirão Grande system (22º47'08"S, 45º28'17"W from July 2001 to April 2002. Fishes were sampled four times each site, during the winter (July 2001, spring (October 2001, summer (February 2002 and autumn (April 2002. Conductivity, pH, water temperature and dissolved oxygen were measured for each site, and elevations in meters were taken by a GPS receiver. The spatial dimension was the main source of variability in the fish distribution in the Ribeirão Grande system. A total of 37 species were caught and the ten most abundant species correspond almost 90% of the total catch. Pareiorhina rudolphi was caught principally in the slope; Characidium lauroi, Trichomycterus itatiayae, Neoplecostomus microps, Astyanax

  12. Distinct classical and molecular cytogenetics of Astyanax marionae ...

    Indian Academy of Sciences (India)

    DIOVANI PISCOR

    2017-08-24

    Aug 24, 2017 ... America (ed. R. Reis, E. S. O. Kullander and C Jr Ferraris), pp. 106–169. Edipucrs, Porto Alegre, Brazil. Martins C. and Galetti Jr P. M. 1999 Chromosomal localization of 5S rDNA genes in Leporinus fish (Anostomidae, Characi- formes). Chromosome Res. 7, 363–367. Mirande J. M. 2010 Phylogeny of the ...

  13. A comunidade de peixes de um riacho de Floresta com Araucária, alto rio Iguaçu, sul do Brasil The fish community in an Araucaria Forest stream, upper Iguaçu River basin, southern Brazil

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    Vinicius Abilhoa

    2008-06-01

    Full Text Available Foram avaliadas a composição, a dieta, as táticas alimentares e ocupação espacial da ictiofauna em um pequeno riacho dentro de um remanescente de Floresta com Araucária. Seis espécies de peixes foram coletadas, pertencentes a três ordens e quatro famílias, totalizando 110 exemplares. No ambiente de corredeira foram coletados e observados apenas Trichomycterus castroi Pinna, 1992 and Trichomycterus davisi Haseman, 1911, enquanto que no ambiente de remanso foram observados e capturados exemplares de Astyanax aff. scabripinnis (sensu Eigenmann, 1921, Astyanax totae Haluch & Abilhoa, 2005, Trichomycterus castroi Pinna, 1992, T. davisi, Phalloceros caudimaculatus (Hensel, 1868 e Jenynsia eigenmanni Haseman, 1911. Dezoito itens alimentares de origem autóctone, seis de alóctone e três de origem incerta foram identificados e tiveram sua freqüência de ocorrência calculada. Uma grande quantidade de itens exclusivos foi registrada, todavia os insetos constituíram a base alimentar mais importante, principalmente na forma de fragmentos e estágios imaturos (larvas e pupas, o que permitiu inferências a respeito de sobreposição alimentar. As espécies registradas no riacho foram classificadas em quatro guildas tróficas e quatro grupos funcionais. As espécies estudadas são capazes de utilizar diversos recursos alimentares e microambientes, o que é favorecido provavelmente pelo seu pequeno porte. O remanescente florestal estudado exerce grande importância no fornecimento de alimento, hábitats e refúgios, fatores importantes para manutenção da biota aquática.The species composition, diet, feeding tactics, and spatial occupation of fishes in a headwater stream which flows within a remaining fragment of Araucaria Forest were studied. One hundred and ten fishes of six species were collected, members of three orders and four families. In riffle areas, only Trichomycterus castroi Pinna, 1992 and Trichomycterus davisi Haseman, 1911 were

  14. Effect of UV radiation on the genetic inactivation of sperm of the bullseye puffer Sphoeroides annulatus (Jenyns, 1842); Efecto de la radiacion UV en la inactivacion genetica del esperma de botete diana Sphoeroides annulatus (Jenyns, 1842)

    Energy Technology Data Exchange (ETDEWEB)

    Arias-Rodriguez, Lenin; Rodriguez-Ibarra, Luz Estela; Del Valle-Pignataro, Gabriela [Laboratorio de Genetica, Centro de Investigacion en Alimentacion y Desarrollo, A. C., Sinaloa (Mexico)

    2004-09-15

    Genetic (DNA) inactivation of fish sperm with ultraviolet irradiation is generally accompanied by a paradoxical effect on survival rates (Hertwig effect). In the present study, sperm samples from ten males bullseye puffer fish (Sphoeroides annulatus) were diluted 1:50 using Cortland's extender solution and used to test the effect of nine ultraviolet doses (0.2-1.0 J cm{sup -}2 ) on motility time in seconds, motility index, and embryo survival rate after fertilizing eggs from five bullseye puffer females. Motility time of sperm irradiated with 0.2-0.9 J cm{sup -}2 were not statistically different from the controls, but sperm irradiated with a dosage of 1.0 J cm{sup -}2 dosage had significant lower motility time. Motility indices (MI) allowed for the statistical differentiation of four groups in relation to their response to different radiation doses: the first had high MI, and included the controls and 0.2-0.3 J cm{sup -}2 treatments; the second had lower MI and included the 0.4-0.7 J cm{sup -}2 treatments; the third showed recovery of MI and included the 0.8-0.9 J cm{sup -}2 treatments; and the fourth showed the lowest MI with the 1.0 J cm{sup -}2 treatment. Embryo survival was highest for the controls and 0.2 J cm{sup -}2 treatment, decreasing in the 0.3-0.4 J cm{sup -}2 treatments, increasing again in the 0.5-0.8 J cm{sup -}2 treatments, until reaching lowest survival in the 0.9-1.0 J cm{sup -}2 treatments. These results indicate that the best ultraviolet dosage to achieve genetic inactivation of sperm of this species is close to 0.7 J cm{sup -}2, a dosage in which fish fry showed typical haploid syndrome characteristics. [Spanish] La inactivacion genetica (ADN) del esperma de peces se realiza mediante luz ultravioleta que, en irradiaciones crecientes, genera efectos paradojicos (efecto Hertwig) en los porcentajes de supervivencia. En este trabajo se diluyeron muestras de semen provenientes de diez machos de botete diana (Sphoeroides annulatus) en solucion extendedora Cortland modificada en dilucion 1:50, y se utilizaron para probar el efecto de nueve dosis de radiacion ultravioleta (0.2-1.0 J cm{sup -}2 ) sobre la duracion de la motilidad en segundos, el indice de motilidad del esperma, y los porcentajes de superviviencia de embriones obtenidos de la fertilizacion de huevos provenientes de cinco hembras de la misma especie. Los tiempos de motilidad del esperma en las muestras irradiadas con 0.2-0.9 J cm{sup -}2 resultaron estadisticamente no diferentes de los controles, mientras que las muestras irradiadas con 1.0 J cm{sup -}2 fueron significativamente menores. El indice de motilidad (IM), por otra parte, permitio la diferenciacion estadistica de cuatro grupos en cuanto a su respuesta a diferentes dosis de radiacion. El primer grupo se caracterizo por valores altos del IM, e incluyo a los controles y a las muestras irradiadas con 0.2-0.3 J cm{sup -}2; el segundo agrupo a las irradiaciones de 0.4 a 0.7 J cm{sup -}2, en las cuales se observo un descenso del IM; en el tercer grupo (0.8-0.9 J cm{sup -}2 ) el IM aumento nuevamente; y en el ultimo (1.0 J cm{sup -}2) se observo el menor IM. En cuanto a los porcentajes de supervivencia, se observo una curva descendente con valores altos de supervivencia en los controles y en las muestras irradiadas con 0.2 J cm{sup -}2, con un descenso en los tratamientos de 0.3 a 0.4 J cm{sup -}2, y una recuperacion significativa a partir del tratamiento de 0.5 y hasta 0.8 J cm{sup -}2, observandose nuevamente un decremento en la supervivencia de los tratamientos de 0.9 a 1.0 J cm{sup -}2 . Ambos resultados, IM y supervivencia, indican que la dosis optima para la produccion de organismos haploides se encuentra cercana a 0.7 J cm{sup -}2. En el tratamiento de 0.7 J cm{sup -}2 se observaron larvas con las caracteristicas tipicas del sindrome haploide, indicando nuevamente que esta puede ser la dosis mas adecuada para producir organismos ginogeneticos.

  15. Multibiomarker response in ten spotted live-bearer fish Cnesterodon decemmaculatus (Jenyns, 1842) exposed to Reconquista river water.

    Science.gov (United States)

    Ossana, N A; Eissa, B L; Baudou, F G; Castañé, P M; Soloneski, S; Ferrari, L

    2016-11-01

    The aim of this paper is to assess the water quality to chemical pollution at Roggero Dam, the headwater of the Reconquista river, and to perform a Cadmium (Cd) contamination pulse simulation through a wide battery of biomarkers which included: genotoxicity and enzymatic biomarker parameters on a neotropical teleost fish namely Cnesterodon decemmaculatus. Water samples were taken in order to determine the river's physicochemical profile. An integrative approach was applied using a biomarker index. The bioassay involved the use of laboratory culture adult animals, acclimatized in moderately hard water (MHW) and fed ad libitum. A semi-static 96h bioassay was conducted and the experimental groups were as follows: [1] river water (Rg); [2] river water + 2mg/L Cd (RgCd); [3] MHW + 2mg/L Cadmium (Cd), positive metal control; [4] MHW + 5mg/L Cyclophosphamide (positive genotoxicity control -CP); [5] MWH, negative control (NC). At the end of the exposure time fishes were sectioned and the following biomarkers were determined: 1) condition factor rate (CF); 2) for the anterior section (A) (head): glutathione (GSH) and protein (Pr) content; 3) for the body midsection (M) (viscera): Pr, GSH, Glutathione-S-transferase (GST), catalase (CAT) and superoxide dismutase (SOD). Blood samples were also taken from the fish specimens to estimate the frequency of micronuclei (MN) as well as other nuclear abnormalities (NA). The physicochemical profile of the river water sample indicated high Copper concentrations. CAT and SOD activity and total Pr content did not show any significant changes. GST activity decreased in fish exposed to Rg, while GSH content decreased significantly for all treatments compared to controls in MHW. These results would seem to point to a reduction in cell defense capability as a result of the depletion antioxidants such as GSH. The NA frequency increased significantly in all treated groups while MN frequency was increased only in Cd and CP groups. Using some the biomarkers measured, a biomarker index was estimated which revealed that fish exposed to Rg were 90% affected or highly affected, while those exposed to RgCd were 80% and Cd 68% affected or highly affected. The obtained results indicate the usefulness of the use of a battery of variables by means of the biomarker index to analyze water quality. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Improved estimates of age, growth and reproduction for the regionally endemic Galapagos sailfin grouper Mycteroperca olfax (Jenyns, 1840).

    Science.gov (United States)

    Usseglio, Paolo; Friedlander, Alan M; DeMartini, Edward E; Schuhbauer, Anna; Schemmel, Eva; Salinas de Léon, Pelayo

    2015-01-01

    The Galapagos Sailfin grouper, Mycteroperca olfax, locally known as bacalao and listed as vulnerable by the IUCN, is culturally, economically, and ecologically important to the Galapagos archipelago and its people. It is regionally endemic to the Eastern Tropical Pacific, and, while an important fishery resource that has shown substantial declines in recent years, to date no effective management regulations are in place to ensure the sustainability of the Galapagos fishery for this species. Previous estimates of longevity and size at maturity for bacalao are inconsistent with estimates for congeners, which brings into question the accuracy of prior estimates. We set out to assess the age, growth, and reproductive biology of bacalao in order to provide more accurate life history information to inform more effective fisheries management for this species. The oldest fish in our sample was 21 years old, which is 2-3 times greater than previously reported estimates of longevity. Parameter estimates for the von Bertalanffy growth function (k = 0.11, L ∞ = 110 cm TL, and to = - 1.7 years) show bacalao to grow much slower and attain substantially larger asymptotic maximum length than previous studies. Mean size at maturity (as female) was estimated at 65.3 cm TL, corresponding to a mean age of 6.5 years. We found that sex ratios were extremely female biased (0.009 M:1F), with a large majority of the individuals in our experimental catch being immature (79%). Our results show that bacalao grow slower, live longer, and mature at a much larger size and greater age than previously thought, with very few mature males in the population. These findings have important implications for the fishery of this valuable species and provide the impetus for a long-overdue species management plan to ensure its long-term sustainability.

  17. Improved estimates of age, growth and reproduction for the regionally endemic Galapagos sailfin grouper Mycteroperca olfax (Jenyns, 1840

    Directory of Open Access Journals (Sweden)

    Paolo Usseglio

    2015-09-01

    Full Text Available The Galapagos Sailfin grouper, Mycteroperca olfax, locally known as bacalao and listed as vulnerable by the IUCN, is culturally, economically, and ecologically important to the Galapagos archipelago and its people. It is regionally endemic to the Eastern Tropical Pacific, and, while an important fishery resource that has shown substantial declines in recent years, to date no effective management regulations are in place to ensure the sustainability of the Galapagos fishery for this species. Previous estimates of longevity and size at maturity for bacalao are inconsistent with estimates for congeners, which brings into question the accuracy of prior estimates. We set out to assess the age, growth, and reproductive biology of bacalao in order to provide more accurate life history information to inform more effective fisheries management for this species. The oldest fish in our sample was 21 years old, which is 2–3 times greater than previously reported estimates of longevity. Parameter estimates for the von Bertalanffy growth function (k = 0.11, L∞ = 110 cm TL, and to = − 1.7 years show bacalao to grow much slower and attain substantially larger asymptotic maximum length than previous studies. Mean size at maturity (as female was estimated at 65.3 cm TL, corresponding to a mean age of 6.5 years. We found that sex ratios were extremely female biased (0.009 M:1F, with a large majority of the individuals in our experimental catch being immature (79%. Our results show that bacalao grow slower, live longer, and mature at a much larger size and greater age than previously thought, with very few mature males in the population. These findings have important implications for the fishery of this valuable species and provide the impetus for a long-overdue species management plan to ensure its long-term sustainability.

  18. So Long and Thanks for All the Fish: Overexploitation of the Regionally Endemic Galapagos Grouper Mycteroperca olfax (Jenyns, 1840).

    Science.gov (United States)

    Usseglio, Paolo; Friedlander, Alan M; Koike, Haruko; Zimmerhackel, Johanna; Schuhbauer, Anna; Eddy, Tyler; Salinas-de-León, Pelayo

    2016-01-01

    The regionally endemic Galapagos Grouper, locally known as bacalao, is one of the most highly prized finfish species within the Galapagos Marine Reserve (GMR). Concerns of overfishing, coupled with a lack of fishing regulations aimed at this species raises concerns about the current population health. We assessed changes in population health over a 30-year period using three simple indicators: (1) percentage of fish below reproductive size (Lm); (2) percentage of fish within the optimum length interval (Lopt); and (3) percentage of mega-spawners in the catch. Over the assessed period, none of the indicators reached values associated with healthy populations, with all indicators declining over time. Furthermore, the most recent landings data show that the vast majority of the bacalao caught (95.7%,) were below Lm, the number of fish within the Lopt interval was extremely low (4.7%), and there were virtually no mega-spawners (0.2%). Bacalao fully recruit to the fishery 15 cm below the size at which 50% of the population matures. The Spawning Potential Ratio is currently 5% of potential unfished fecundity, strongly suggesting severe overfishing. Our results suggest the need for bacalao-specific management regulations that should include minimum (65 cm TL) and maximum (78 cm TL) landing sizes, slot limits (64-78 cm TL), as well as a closed season during spawning from October to January. It is recognized that these regulations are harsh and will certainly have negative impacts on the livelihoods of fishers in the short term, however, continued inaction will likely result in a collapse of this economically and culturally valuable species. Alternative sources of income should be developed in parallel with the establishment of fishing regulations to limit the socio-economic disruption to the fishing community during the transition to a more sustainable management regime.

  19. Toxicidade subcrônica de lambaris Astyanax aff. bimaculatus expostos ao zinco

    OpenAIRE

    Condessa, Suellen Silva

    2009-01-01

    Muitos metais ocorrem naturalmente em ambientes aquáticos e são classificados como poluentes somente quando adicionados pelo homem em quantidades suficientes para produzir efeitos deletérios em organismos. Dentre estes metais já existentes no ambiente aquático pode-se citar o zinco (Zn) que é um elemento essencial para os seres vivos. Em concentrações elevadas, o Zn pode se tornar tóxico aos seres vivos por reduzir os níveis séricos de cobre, causando a diminuição da imunidade. O presente est...

  20. Carryover of aflatoxins from feed to lambari fish (Astyanax altiparanae) tissues.

    Science.gov (United States)

    Michelin, E C; Massocco, M M; Godoy, S H S; Baldin, J C; Yasui, G S; Lima, C G; Rottinghaus, G E; Sousa, R L M; Fernandes, A M

    2017-02-01

    The aim of this study was to verify the carryover of aflatoxin B1 from feed to lambari fish. Aflatoxins (AF) were incorporated into feed, checking the levels by HPLC. Treatments were: Control, feed without toxin; A, feed + 10 µg AFB1 kg(-)(1); B, feed + 20 µg AFB1 kg(-)(1); and C, feed + 50 µg AFB1 kg(-)(1). Juveniles of lambari fish were placed in 12 aquariums at a density of 50 fish/m(2). Fish were fed twice a day with extruded feed, at 5% of animal biomass. The unit sample was constituted by a pool of 10 fish. AFs B1, B2, G1, G2 and M1 were quantified by HPLC in fish muscle and liver after 30, 60, 90 and 120 days of experiment. There was accumulation of AFs is fish liver and muscle, mainly after 90 days. Fish from treatment C had higher levels of AFB1 in muscle when compared with the others, and AFB1 in muscle at 120 days was similar to the levels in feed. Therefore, when lambari fish is exposed on a daily and long-term basis to AFs in feed, the regulation limits for AFs in animal feed do not guarantee safety for consumers.

  1. Population structure and reproductive aspects of puffer fish Sphoeroides annulatus (Jenyns, 1842 (Osteichthyes: Tetraodontidae, landed in Teacapán, Sinaloa, Mexico

    Directory of Open Access Journals (Sweden)

    María Candelaria Valdez-Pineda

    2014-03-01

    Full Text Available The puffer fish Sphoeroides annulatus is an important target species for the artisanal fishing fleets of NW Mexico. To obtain information on population structure of the local stock, we determined the total length and total weight (TL and TW ranges, sex ratio and reproductive stages of 745 specimens of this species, landed from May 2010 to April 2011 in Teacapán, Sinaloa, NW Mexico. TL ranged from 15 to 40 cm and TW from 100 to 1600 g. There were no differences between mean TL (27.41 ± 4.14 cm and TW (534.5 ± 226.0 g of males and females respectively. Sex ratio was not significantly different (χ2 = 0.03, P > 0.05 from 1F:1M. The length-weight relationship for both sexes was TW = 0.044TL2.815, R² = 0.895. The value of the slope b was significantly lower than 3 (P < 0.05, and indicated negative allometric growth. The distribution of maturity stages indicated one main reproductive period from June to September and one less intense, from November to December for females, and in December for males. Size at first maturity (L50% of females was 26.52 cm and that of males was 27.41 cm.

  2. Feeding ω-3 PUFA enriched rotifers to Galaxias maculatus (Jenyns, 1842 larvae reared at different salinity conditions: effects on growth parameters, survival and fatty acids profile

    Directory of Open Access Journals (Sweden)

    Patricio Dantagnan

    2013-07-01

    Full Text Available Despite the well known importance of ω-3 polyunsaturated fatty acids (PUFA in marine and freshwater fish larvae, there are few studies on how essential fatty acid requirements and composition on whole body can be altered by changes in water salinity. The present study aimed to determine the effect of salinity on ω-3 PUFA requirements, larval growth survival and fatty acid composition of Galaxias maculatus larvae cultured at two different salinities (0 and 15 g L-1 for 20 days while fed rotifers containing two different levels of ω-3 PUFA (1.87 and 3.16%. The results denoted a marked difference in ω-3 PUFA requirements and in the pattern of fatty acid deposition in the whole body of larvae reared at different salinities, depending of ω-3 PUFA in diets. Thus, to improve growth and survival larvae of G. maculatus reared at 0 g L-1 require higher levels of ω-3 PUFA, principally 18:3 ω-3. Larvae reared at salinities of 15 g L-1 require low levels of ω-3 PUFA for optimal survival, especially 18:3 ω-3. Eicosapentaenoic acid and docosahexaenoic acid content in the whole body of larvae was also affected by water salinity.

  3. Efecto de la ración alimenticia sobre la maduración gonadal y acumulación de grasa de anchoveta peruana (Engraulis ringens Jenyns, 1842 en cautiverio Effect of feeding ration on gonad maturation and fat accumulation in Peruvian anchovy (Engraulis ringens Jenyns, 1842 in captivity

    Directory of Open Access Journals (Sweden)

    Carlos Espinoza

    2009-01-01

    Full Text Available Se evaluó el efecto de la ración alimenticia sobre la tasa de maduración gonadal, el desempeño de las gónadas maduras y la redistribución de la energía consumida en gónada, músculo o grasa corporal en ejemplares de anchoveta peruana Engraulis ringens en condiciones de cautiverio Estos resultados ayudan a comprender los procesos reproductivos ocurridos en el medio natural ante alteraciones de factores ambientales tales como los eventos El Niño y La Niña, de gran implicancia en el ecosistema y las pesquerías del Pacífico oriental. El tiempo trascurrido desde el estadio inmaduro hasta vitelogénico fue de 45 días bajo condiciones alimenticias energéticamente óptimas y temperatura alrededor de 16,5°C (46,1 cal g-1 pez día-1 . Las hembras alimentadas con 138,3 cal g-1 pez día-1 alcanzaron la máxima vitelogénesis en 30 días y, aunque el alimento fue excesivo, no incrementaron su masa muscular pero si presentaron mayor acumulación de grasa corporal y presencia de ovocitos más grandes, lo cual indica un incremento en el almacenamiento energético en la hembra y su progenie. Los ovocitos vitelogénicos de los peces alimentados con 46,1 cal g-1 pez día-1 presentaron atresia más rápido que los ovocitos vitelogénicos de peces alimentados con 138,3 cal g-1 pez día-1 . Aunque la cantidad de alimento fue adecuada, las hembras no desovaron durante el experimento. En machos, la disponibilidad de alimento también aceleró la maduración gonadal pero la expulsión de espermatozoides parece haber estado condicionada por la presencia de hembras con ovocitos en máximo estado de vitelogénesis.We analyzed the effect that feeding rations have on gonad maturation, mature gonad performance, and the redistribution of the energy taken up by the gonads, muscle, and body fat in captive specimens of Peruvian anchovy (Engraulis ringens. These results help us understand the reproductive processes occurring in the natural environment given changes in the environmental factors such as El Niño and La Niña events, which heavily affect the ecosystem and fisheries in the East Pacific. The specimens required 45 days under optimal feeding conditions (46.1 cal g-1 fish day-1 and at a temperature of 16,5°C to go from an unyoked to a vitellogenic stage. Those females fed 138.3 cal g-1 fish day-1 reached maximum vitellogenesis in 30 days. Despite the excessive amount of food, the specimens' muscle mass did not increase. However, greater body fat accumulation and larger vitellogenic ovocytes were observed, indicating augmented energy storage for the female and her offspring. The yoked oocytes from fish fed 46.1 cal g-1 fish day-1 became atretic earlier than oocytes from fish fed 138.3 cal g-1 fish day-1. Although the food supply was adequate, the females did not spawn during the experiment. In males, food availability also accelerated gonad maturation, but the release of sperm was apparently conditioned by the presence of females with ovocytes in the advanced vitellogenic stage.

  4. Dynamics and cytochemistry of oogenesis in Astyanax fasciatus (Cuvier (Teleostei, Characiformes, Characidae from Rio Sapucaí, Minas Gerais State, Brazil

    Directory of Open Access Journals (Sweden)

    José Antônio Dias Garcia

    2001-12-01

    Full Text Available Oogenesis involves a set of transformations which are undergone by female germ cells These cells change into oogonias and then into mature oocytes. Sexually mature female fish were collected monthly, during one year, from the Sapucaí River, a tributary of the Rio Grande, which is part of the Furnas Reservoir in the state of Minas Gerais. During the several stages of maturation, we observed small round oogonias with a large nucleus, a single nucleolus, and weakly stained cytoplasm with eosinophilic granules. The primary oocytes showed a large basophilic nucleus, with a developed peripheral nucleolus and a reduced cytoplasm. The previtellogenic oocytes presented voluminous cytoplasm and nucleus with several small peripheral nucleoli. The oocytes underwent vitellogenesis with the development of the zona radiata and the follicle cells. Their cytochemical reactions indicated that the two layers of the zona radiata of A. fasciatus contained proteins and polysaccharides. The initially squamous follicle cells, became cuboidal. In mature oocytes, the nucleus moved toward the periphery, next to the micropyle, and the yolk granules formed by proteins, fulfilled the cytoplasm. The clear unstained vesicles are likely to be the cortical alveoli in the perivitelline region.

  5. Níveis de inclusão do ácido linoléico conjugado (CLA) em dietas para lambaris-do-rabo-amarelo (Astyanax altiparanae)

    OpenAIRE

    Campelo,Daniel Abreu Vasconcelos

    2012-01-01

    Entre as pesquisas relacionadas ao estudo de ácidos graxos, a utilização do ácido linoléico conjugado (CLA) tem se destacado por promover efeitos no crescimento, eficiência alimentar e composição corporal dos peixes, melhorando assim, a produção final. Para a saúde humana, muitos trabalhos com a utilização do CLA, vêm sendo realizados em função de seus efeitos benéficos, principalmente por sua ação anticancerígena e de prevenção da obesidade. Estudos correlacionando os efeitos benéficos do co...

  6. Diet of Cnesterodon decemmaculatus (Poeciliidae and Jenynsia multidentata (Anablepidae in a hypertrophic shallow lake of Uruguay Dieta de Cnesterodon decemmaculatus (Poeciliidae y Jenynsia multidentata (Anablepidae en un lago hipereutrófico de Uruguay

    Directory of Open Access Journals (Sweden)

    Federico Quintans

    2009-03-01

    Full Text Available Se analizaron las dietas de Cnesterodon decemmaculatus (Jenyns, 1842 y Jenynsia multidentata (Jenyns, 1842 en el Lago Rodó, un lago urbano hipereutrófico de Montevideo, Uruguay. Ambas especies mostraron un comportamiento omnívoro. Los ítems más consumidos por C. decemmaculatus fueron zooplancton, perifiton, fitoplancton y detritos; la dieta de J. multidentata incluyó zooplancton, insectos, crustáceos y peces juveniles. Estos resultados sugieren que ambas especies pueden actuar como planctívoros facultativos. La comunidad de peces de este lago se caracteriza por la dominancia de C. decemmaculatus y J. multidentata. Bajo esta condición, la depredación sobre el zooplancton de gran tamaño podría indirectamente estar contribuyendo a una alta abundancia de fitoplancton y una baja transparencia del agua.Diet of Cnesterodon decemmaculatus (Jenyns, 1842 and Jenynsia multidentata (Jenyns, 1842 were analysed in Lake Rodó, an urban hypertrophic lake from Montevideo, Uruguay. Both species displayed omnivory. The most consumed items for C. decemmaculatus were zooplankton, periphyton, phytoplankton and detritus; the diet of J. multidentata included zooplankton, insects, crustaceans and juvenile fish. Our results suggest that both species could be acting as facultative planktivores. The fish community of this lake is characterised by the dominance of C. decemmaculatus and J. multidentata. Under this condition, predation on large-bodied zooplankton could indirectly be contributing to maintain a high phytoplankton abundance and a low water transparency.

  7. Avaliação da toxicidade de nanopartículas de dióxido de titânio (TiO2) e chumbo inorgânico (Pbll) em Astyanax altiparanae (Characidae)

    OpenAIRE

    Lirola, Juliana Roratto

    2016-01-01

    Orientadora : Profª Drª Marta Margarete Cestari Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Genética. Defesa: Curitiba, 22/03/2016 Inclui referências : f. 70-85 Resumo: O aumento das indústrias juntamente ao crescimento populacional tem elevado de forma considerável os níveis de poluição no meio ambiente e o ambiente aquático é o ecossistema mais suscetível ao despejo de substâncias. Diversas alterações estrutura...

  8. Feeding of two Cichlidae species (Perciformes in an hypertrophic urban lake

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    Yafe Alejandro

    2002-01-01

    Full Text Available Diet of two cichlid species, Cichlasoma facetum (Jenyns, 1842, and Gymnogeophagus rhabdotus Hensel, 1870, was studied in Rodó Lake, an urban hypertrophic lake in Uruguay. The stomach contents from 192 individuals of C. facetum and 202 of G. rhabdotus, obtained through seasonal sampling in the year 2000, were analyzed. The occurrence frequency and the alimentary importance index of each food item were calculated for each season and size class in both species. Cichlasoma facetum fed upon insects (mainly chironomid larvae and pupae, fish (Cnesterodon decemmaculatus Jenyns, 1842, and vegetals (algae, periphyton and macrophytes debris; large individuals also fed upon the freshwater shrimp Palaemonetes argentinus Nobili, 1901. Gymnogeophagus rhabdotus consumed zooplankton (mainly copepods, vegetals (algae and detritus and Chironomidae larvae in a lesser extent.

  9. The Comparative Organismal Approach in Evolutionary Developmental Biology: Insights from Ascidians and Cavefish.

    Science.gov (United States)

    Jeffery, William R

    2016-01-01

    Important contributions to evolutionary developmental biology have been made using the comparative organismal approach. As examples, I describe insights obtained from studies of Molgula ascidians and Astyanax cavefish. © 2016 Elsevier Inc. All rights reserved.

  10. Evolutionary Convergence on Sleep Loss in Cavefish Populations

    National Research Council Canada - National Science Library

    Duboué, Erik R; Keene, Alex C; Borowsky, Richard L

    2011-01-01

    .... The characin fish, Astyanax mexicanus, has eyed surface and numerous blind cave populations. The cave populations are largely independent in their origins, and the species is ideal for studying the genetic bases of convergent evolution...

  11. Variation in the diet of a small characin according to the riparian zone coverage in an Atlantic Forest stream, northeastern Brazil/Variação na dieta de um pequeno Characidae de acordo com a cobertura da mata ripária em um riacho da Mata Atlântica, nordeste do Brasil

    National Research Council Canada - National Science Library

    Márcia Emília de Jesus Trindade; Alexandre Peressin; Maurício Cetra; Ricardo Jucá-Chagas

    2013-01-01

      In this study, the authors present data from the diet of Astyanax vermilion which were used as a tool to compare two sites of streams with different vegetation cover in Ribeirao Limoeiro, Cachoeira River Basin, BA...

  12. Lepeophtheirus simplex sp. n., a caligid copepod (Siphonostomatoida) parasitic on "botete" (bullseye puffer, Sphoeroides annulatus) in Sinaloa, Mexico.

    Science.gov (United States)

    Ho, J S; Gómez, S; Fajer-Avila, E

    2001-01-01

    A new species of caligid copepod, Lepeophtheirus simplex sp. n., parasitic on bullseye puffer, Sphoeroides annulatus (Jenyns) in Sinaloa, Mexico is described. The new species is distinguished from its congeners by the possession of (1) a maxillule with simple dentiform process; (2) a sternal furca with sharply pointed, curved tines; (3) a 2-segmented exopod of leg 3 with simple, slender spine on proximal segment; (4) a 3-segmented exopod of leg 4 with a long proximal, outer spine; and (5) the terminal claw of male antenna with a large, tridentate, medial protuberance.

  13. The life history of Pygidiopsis macrostomum Travassos, 1928 (Digenea: Heterophyidae

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    Susana Balmant Emerique Simões

    2009-02-01

    Full Text Available The life history of the trematode Pygidiopsis macrostomum Travassos, 1928 is described for the first time. Rediae and cercariae were obtained from naturally infected snails Heleobia australis (d´Orbigny, a new first intermediate host. Metacercariae were found encysted in the mesenteries of three naturally infected guppies, Phalloptychus januarius (Hensel, Jenynsia multidentata (Jenyns (new host records and Poecilia vivipara Bloch and Schneider. Experimental infections were successfully completed in the intermediate hosts H. australis and Poe. vivipara reared in the laboratory and hamsters Mesocricetus auratus Waterhouse were utilised as a definitive host.

  14. Parasites of four ornamental fish from the Chumucuí River (Bragança, Pará, Brazil).

    Science.gov (United States)

    Fujimoto, Rodrigo Yudi; Barros, Zaira Monik Nunes de; Marinho-Filho, Adjalbas Nunes; Diniz, Daniel Guerreiro; Eiras, Jorge Costa

    2013-01-01

    The objective of the present study was to evaluate the parasite fauna of four species of ornamental fish collected in the Chumucuí River, municipality of Bragança, Pará, Brazil. From June 2006 to December 2007. Fishes (n=307) belonging to four species were collected, including 23 specimens of Moenkhausia sanctaefilomenae (redeye tetra), 37 Carnegiella strigata (marbled hatchetfish), 7 Chilodus punctatus (spotted headstander), and 240 Astyanax bimaculatus (twospot astyanax). The parasites found belonged to three taxa: monogeneans in the gills, nematodes (larvae of Capillaria sp. and Contracaecum sp.) in the digestive tract and liver and acanthocephalans (Quadrigyrus torquatus, Q. brasiliensis and Q. nickoli) in the stomach and intestine. Astyanax bimaculatus presented higher prevalence of acanthocephalans in the wet season, and lower prevalence of nematodes in the dry season. The possible importance of these parasites in the exportation of ornamental fish is discussed.

  15. Reprodução de peixes (Osteichthyes em afluentes do reservatório de Volta Grande, Rio Grande, Sudeste do Brasil

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    Braga Francisco Manoel de Souza

    2001-01-01

    Full Text Available The most abundant species caught in the tributaries of the Volta Grande dam, Buriti, Divisa and Água Comprida streams were Plagioscion squamosissimus (Heckel, 1840, Pimelodus maculatus Lacépède 1803, Myleus tiete (Eigenmann & Norris, 1900, Astyanax bimaculatus (Linnaeus, 1758 and A. fasciatus (Cuvier, 1819. Plagioscion squamosissimus and Pimelodus maculatus do not have reproduction activity in the area, they just use the creeks to food and growth. Myleus tiete and Astyanax bimaculatus use the area to reproduction whereas A. fasciatus uses it to reproduction, food and growth.

  16. Markiana nigripinnis (Perugia, 1891 as a putative member of the subfamily Stevardiinae (Characiformes: Characidae: spermatic evidence

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    Clarianna Martins Baicere-Silva

    Full Text Available The genus Markiana was until recently recognized as incertae sedis in the family Characidae, even though alternative placements for this genus have been advanced since its original description. More recently, it was hypothesized that Markiana nigripinnis is part of a clade informally named the Astyanax clade, indicating the putative close relationship of Markiana with the genus Astyanax. Examination of sperm ultrastructure of representatives of Astyanax and M. nigripinnis shows no evidence for this hypothesized close relationship. Rather, the spermatozoa of M. nigripinnis share characters found in spermatozoa of the non-inseminating members of the subfamily Stevardiinae, such as an angle of nuclear rotation equal to 85º resulting in a lateral position of the double nuclear fossa and flagellum. As with the non-inseminating Stevardiinae, sperm nuclei are also slightly elongate toward the flagellum, the proximal centriole is partially inside the nuclear fossa and anterior and oblique to the distal centriole, and the midpiece is short and strongly asymmetric. Additionally, M. nigripinnis shares with the other members of the Stevardiinae the presence of only four teeth in the inner row of the premaxillary and a short triangular ectopterygoid, which is never more than twice the length of the palatine.

  17. Functional modularity in lake-dwelling characin fishes of Mexico

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    Claudia Patricia Ornelas-García

    2017-09-01

    Full Text Available Modular evolution promotes evolutionary change, allowing independent variation across morphological units. Recent studies have shown that under contrasting ecological pressures, patterns of modularity could be related to divergent evolution. The main goal of the present study was to evaluate the presence of modular evolution in two sister lacustrine species, Astyanax aeneus and A. caballeroi, which are differentiated by their trophic habits. Two different datasets were analyzed: (1 skull X-rays from 73 specimens (35 A. aeneus and 38 A. caballeroi to characterize skull variation patterns, considering both species and sex effects. For this dataset, three different modularity hypotheses were tested, previously supported in other lacustrine divergent species; (2 a complete body shape dataset was also tested for four modularity hypotheses, which included a total of 196 individuals (110 Astyanax aeneus and 86 A. caballeroi. Skull shape showed significant differences among species and sex (P < 0.001, where Astyanax caballeroi species showed an upwardly projected mandible and larger preorbital region. For the skull dataset, the modularity hypothesis ranked first included three partitioning modules. While for the complete body dataset the best ranked hypothesis included two modules (head vs the rest of the body, being significant only for A. caballeroi.

  18. Parasites of four ornamental fish from the Chumucuí River (Bragança, Pará, Brazil Parasitas de quatro peixes ornamentais do Rio Chumucuí (Bragança-Pará, Brasil

    Directory of Open Access Journals (Sweden)

    Rodrigo Yudi Fujimoto

    Full Text Available The objective of the present study was to evaluate the parasite fauna of four species of ornamental fish collected in the Chumucuí River, municipality of Bragança, Pará, Brazil. From June 2006 to December 2007. Fishes (n=307 belonging to four species were collected, including 23 specimens of Moenkhausia sanctaefilomenae (redeye tetra, 37 Carnegiella strigata (marbled hatchetfish, 7 Chilodus punctatus (spotted headstander, and 240 Astyanax bimaculatus (twospot astyanax. The parasites found belonged to three taxa: monogeneans in the gills, nematodes (larvae of Capillaria sp. and Contracaecum sp. in the digestive tract and liver and acanthocephalans (Quadrigyrus torquatus, Q. brasiliensis and Q. nickoli in the stomach and intestine. Astyanax bimaculatus presented higher prevalence of acanthocephalans in the wet season, and lower prevalence of nematodes in the dry season. The possible importance of these parasites in the exportation of ornamental fish is discussed.O objetivo do presente trabalho foi avaliar a fauna parasitária de quatro espécies de peixes ornamentais capturados no rio Chumucuí, no município de Bragança-PA. Foram coletados um total de 307 peixes pertencentes a 4 espécies, sendo elas: Moenkhausia sanctaefilomenae (olho de fogo, n = 23, Carnegiella strigata (borboleta, n = 37, Chilodus punctatus (cabeça-para-baixo, n = 7 e Astyanax bimaculatus (lambari, n = 240 coletados de junho de 2006 a dezembro de 2007. Foram observados 3 taxa parasitando os peixes: monogenéticos nas brânquias, nematóides (larvas de Capillaria sp. e Contracaecum sp. no trato digestório e fígado e acantocéfalos (Quadrigyrus torquatus, Q. brasiliensis e Q. nickoli no estômago e intestino. Astyanax bimaculatus apresentou maior prevalência de acantocéfalos na estação chuvosa, menor prevalência de nematóides na estação seca. Discute-se a eventual importância destes parasitas na exportação de peixes ornamentais.

  19. Caracterización del consumo de larvas de culícidos (Diptera en dos especies de peces indígenas de la zona central de Argentina

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    Alejo F. Bonifacio

    2014-09-01

    Full Text Available Los mosquitos representan una amenaza para la salud del hombre y de los animales debido a que actúan como vectores de distintas enfermedades. Especies de peces nativos son potenciales candidatos a tenerse en cuenta para control biológico de poblaciones de culícidos. Experiencias de consumo de media hora y de 24 horas por Cnesterodon decemmaculatus (Jenyns, 1842 y Jenynsia multidentata (Jenyns, 1842 se llevaron a cabo con larvas de Culex pipiens (Linnaeus, 1758, midiéndose longitud estándar, ancho de boca y peso en individuos de las dos especies. En ambas pruebas, J. multidentata consumió más C. pipiens que C. decemmaculatus, consumiendo las hembras de esta última especie más que los machos (e igual a ambos sexos de J. multidentata en la prueba de 24 horas de duración. Estos resultados no variaron cuando se compararon tantos consumos absolutos o relativos para las pruebas de media hora, sin embargo cuando se compararon los consumos relativos al peso no se encontraron diferencias entre las especies para las pruebas de 24 horas. Análisis de regresión entre las tasas de consumo versus las variables morfométricas y el peso mostraron poco valor explicativo en las pruebas de media hora de duración, mientras que en las pruebas de 24 horas de duración los análisis de regresión tuvieron un mayor valor explicativo, especialmente con el ancho de la boca. Por último, pruebas de media hora de duración fueron llevadas a cabo exponiendo a hembras de C. decemmaculatus con larvas de C. pipiens y Aedes aegypti (Linnaeus, 1742 observándose una fuerte preferencia por las últimas. Este trabajo permitió evidenciar que las especies de peces en estudio presentan grandes diferencias en las tasas de consumo de C. pipiens en periodos cortos. Estas diferencias se atenuaron cuando las tasas de consumo se prolongaron y hasta llegar a desaparecer cuando el peso se tuvo en cuenta.

  20. Markiana nigripinnis (Perugia, 1891 as a putative member of the subfamily Stevardiinae (Characiformes: Characidae: spermatic evidence

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    Clarianna Martins Baicere-Silva

    2011-06-01

    Full Text Available The genus Markiana was until recently recognized as incertae sedis in the family Characidae, even though alternative placements for this genus have been advanced since its original description. More recently, it was hypothesized that Markiana nigripinnis is part of a clade informally named the Astyanax clade, indicating the putative close relationship of Markiana with the genus Astyanax. Examination of sperm ultrastructure of representatives of Astyanax and M. nigripinnis shows no evidence for this hypothesized close relationship. Rather, the spermatozoa of M. nigripinnis share characters found in spermatozoa of the non-inseminating members of the subfamily Stevardiinae, such as an angle of nuclear rotation equal to 85º resulting in a lateral position of the double nuclear fossa and flagellum. As with the non-inseminating Stevardiinae, sperm nuclei are also slightly elongate toward the flagellum, the proximal centriole is partially inside the nuclear fossa and anterior and oblique to the distal centriole, and the midpiece is short and strongly asymmetric. Additionally, M. nigripinnis shares with the other members of the Stevardiinae the presence of only four teeth in the inner row of the premaxillary and a short triangular ectopterygoid, which is never more than twice the length of the palatine.O gênero Markiana até recentemente foi reconhecido como incertae sedis na família Characidae, apesar da localização alternativa para este gênero desde sua descrição original. Mais recentemente, surgiu a hipótese de que Markiana nigripinnis faz parte de um clado chamado informalmente de "Astyanax clade", indicando a suposta relação de Markiana com o gênero Astyanax. A análise da ultraestrutura dos espermatozoides de representantes do gênero Astyanax e M. nigripinnis não mostra nenhuma evidência de estreita relação. Pelo contrário, os espermatozóides de M. nigripinnis compartilham o padrão encontrado nos espermatozoides dos membros n

  1. Cavefish eye loss in response to an early block in retinal differentiation progression.

    Science.gov (United States)

    Stemmer, Manuel; Schuhmacher, Laura-Nadine; Foulkes, Nicholas S; Bertolucci, Cristiano; Wittbrodt, Joachim

    2015-02-15

    The troglomorphic phenotype shared by diverse cave-dwelling animals is regarded as a classical example of convergent evolution. One unresolved question is whether the characteristic eye loss in diverse cave species is based on interference with the same genetic program. Phreatichthys andruzzii, a Somalian cavefish, has evolved under constant conditions in complete darkness and shows severe troglomorphic characteristics, such as complete loss of eyes, pigments and scales. During early embryonic development, a complete eye is formed but is subsequently lost. In Astyanax mexicanus, another blind cavefish, eye loss has been attributed to interference during eye field patterning. To address whether similar pathways have been targeted by evolution independently, we investigated the retinal development of P. andruzzii, studying the expression of marker genes involved in eye patterning, morphogenesis, differentiation and maintenance. In contrast to Astyanax, patterning of the eye field and evagination of the optic vesicles proceeds without obvious deviation. However, the subsequent differentiation of retinal cell types is arrested during generation of the first-born cell type, retinal ganglion cells, which also fail to project correctly to the optic tectum. Eye degeneration in both species is driven by progressive apoptosis. However, it is retinal apoptosis in Phreatichthys that progresses in a wave-like manner and eliminates progenitor cells that fail to differentiate, in contrast to Astyanax, where lens apoptosis appears to serve as a driving force. Thus, evolution has targeted late retinal differentiation events, indicating that there are several ways to discontinue the development and maintenance of an eye. © 2015. Published by The Company of Biologists Ltd.

  2. A new species of Auriculostoma (Trematoda: Allocreadiidae) from the intestine of Brycon guatemalensis (Characiformes: Bryconidae) from the Usumacinta River Basin, Mexico, based on morphology and 28S rDNA sequences, with a key to species of the genus.

    Science.gov (United States)

    Hernández-Mena, David Iván; Lynggaard, Christina; Mendoza-Garfias, Berenit; DE León, Gerardo Pérez-Ponce

    2016-11-22

    We describe a new species of Auriculostoma Scholz, Aguirre-Macedo & Choudhury, 2004 based on several sources of information including morphology (light and scanning electron microscopy [SEM]), sequences of two nuclear genes, host association, and geographical distribution. Morphologically, the new species most closely resembles Auriculostoma astyanace Scholz, Aguirre-Macedo & Choudhury, 2004, but differs by having deeply lobated testes and cirrus-sac extending posteriorly to seminal receptacle level. Auriculostoma lobata n. sp. can be readily distinguished from all the other congeners by the combination of the following characters: testes located in tandem, testes deeply lobated, and larger body size. A phylogenetic analysis using 28S rDNA sequences along with those available for other allocreadiid trematodes, revealed that the new species is a sister taxon of A. astyanace, a species described from the banded astyanax, Astyanax fasciatus (Cuvier) in Nicaragua. Auriculostoma totonacapanensis Razo-Mendivil, Mendoza-Garfias, Pérez-Ponce de León & Rubio-Godoy, 2014 from the Mexican tetra, Astyanax mexicanus (De Filippi) in Mexico is the sister taxon of A. astyanace plus the new species. Genetic divergence levels for the 28S rDNA and ITS2 were estimated among the Middle-American species of Auriculostoma infecting characiforms. The validity of the new species is then established by reliable morphological differences, its host association to bryconids (Brycon guatemalensis Regan), restricted geographical distribution (Usumacinta and Lacantun River basins), and genetic divergence levels, albeit relatively low. A morphometric comparison between the new species and the other seven congeneric species was undertaken and, in addition, a taxonomic key to identify the species contained in the genus Auriculostoma, widely distributed across the Americas, is provided.

  3. Food-resource partitioning among fish species from a first-order stream in northwestern Paraná, Brazil

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    Jislaine Cristina da Silva

    Full Text Available This study addressed the feeding ecology of fish fauna from a first-order stream located in a rural area. The purposes were to evaluate the influence of interspecific, seasonal and spatial factors on the diet, examine the dietary overlap, and determine the predominant food sources. Sampling was conducted in December 2007, September 2008, and March 2009, in three 50-m stretches of Itiz stream (upstream, intermediate, and downstream, through electrofishing. A total of 1,102 stomach contents were analyzed from 14 species, by the volumetric method. In general, allochthonous resources were predominant in the diets. Astyanax aff. fasciatus, Astyanax aff. paranae, Astyanax bockmanni, and Bryconamericus aff. iheringi consumed a higher proportion of plant remains, and Bryconamericus stramineus consumed predominantly Hymenoptera. The diets of Cetopsorhamdia iheringi, Characidium aff. zebra, Imparfinis schubarti, and Trichomycterus sp. consisted of aquatic insects, especially immature forms of Trichoptera, Ephemeroptera, Plecoptera, and Diptera. Hypostomus ancistroides, Hisonotus sp., Poecilia reticulata, and Rineloricaria aff. pentamaculata exploited mainly detritus, while Rhamdia quelen used a variety of items, predominantly terrestrial insects. Detrended Correspondence Analysis (DCA showed a clear distinction among the species, with different morphology and feeding tactics. The Multi-Response Permutation Procedure (MRPP supported this differentiation, and also indicated significant spatial and temporal variations in the dietary composition; the Indicator Value Method (IndVal indicated the main items that contributed to these differences. The diet overlap among species was low (< 0.4 to around 78% of pairs, and the mean value did not vary significantly among the sites or between hydrological periods within each site. According to the null model of Pianka’s index, the values for dietary overlap were significantly higher than expected at random, showing

  4. Three monogeneans parasitic on marine sciaenid fish from Peru including description of Cynoscionicola veranoi n. sp. (Microcotylidae), and redescription of C. americanus Tantaleán, Martínez and Escalante, 1987 and Hargicotyle sciaenae Oliva and Luque, 1989 (Diclidophoridae).

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    Chero, Jhon D; Cruces, Celso L; Saez, Gloria; Luque, José L

    2017-09-26

    Cynoscionicola veranoi n. sp. (Monogenea: Microcotylidae) is described based on specimens collected from the gills of lorna drum Sciaena deliciosa (Tschudi, 1846) (Sciaenidae) from Peru. The new species can be differentiated from the other congeneric species by the combination of the following characteristics: (1) haptor with two types of clamps, (2) number and shape of the spines in anterolateral pouches of genital atrium (10-11 curved spines and 3-4 short and bifid spines with a knob in each lateral margin), (3) number and shape of the spines in posterolateral pouches of genital atrium (13-18 bifid spines), (4) 4-6 small spherical unarmed pouches in the genital atrium, and (5) 10-15 testes. In addition, a redescription of Cynoscionicola americanus Tantaleán, Martínez and Escalante, 1987 and Hargicotyle sciaenae Oliva and Luque, 1989 (Diclidophoridae) based on examination of type material and newly collected specimens from snakehead kingcroaker Menticirrhus ophicephalus (Jenyns, 1840) and S. deliciosa (type hosts), respectively, are provided herein.

  5. Abundance patterns of early stages of the Pacific sardine (Sardinops sagax during a cooling period in a coastal lagoon south of the California Current

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    René Funes-Rodríguez

    2011-11-01

    Full Text Available Abundance patterns of eggs and larvae of the Pacific sardine, Sardinops sagax (Jenyns, 1842, in Bahía Magdalena, Baja California Sur, were analysed during a cooling period south of the California Current from 2005 to 2009. The thermohaline characteristics and zooplankton abundance were good descriptors of the potential spawning habitat. Individual quotient analyses showed a predominance of eggs and larvae within a SST range of 16 to 18°C, at low salinities (33.9-34.1 and at low density gradient variability (0.009-0.029, associated with deeper waters (25-40 m near the main entrance, where the transparency was intermediate (6-8 m and zooplankton abundance was relatively high ( > 316 ml/1000 m3. Increments within different class intervals meant that neither dissolved inorganic nitrogen (DIN, phosphates nor chlorophyll a predominated. The large interannual fluctuations in sardine spawning activity and preferential temperatures observed in historical and recent data suggest that two sardine stocks spawn in Bahia Magdalena: one stock spawned in the period 1981-1989 and one stock spawned in the period 1997-2009. The influence of cooling and warming periods as additional components of the regional environmental framework is analysed and discussed.

  6. Novas considerações morfológicas e sistemáticas sobre os Procamallanus brasileiros (Nematoda, Camallanoidea On Brazilian Procamallanus (Nematoda, Camallanoidea

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    R. Magalhães Pinto

    1976-01-01

    Full Text Available Mais uma vez os autores apresentam os resultados obtidos, após examinarem 62 amostras de Procamallanus brasileiros parasitas de peixes dulcícolas. Duas novas espécies são propostas: Procamallanus (Spirocamallanus pexatus e Procamallanus (Procamallanus peraccuratus, esta representando a primeira ocorrência do subgênero no Brasil. Procamallanus (Spirocamallanus probus pinto & fernandes, 1972, é considerada sinônimo de Procamallanus (Spirocamallanus inopinatus Travassos, Artigas & Pereira, 1928. Um lote não identificado, por insuficiência de dados, é incluído como Procamallanus (Spirocamallanus sp.After studying 63 Procamallanus samples recovered from Brazilian freshwater fishes, the authors in this third article on the subject propose two new species: Procamallanus Spinocamallanus pexatus from Pygidium brasiliensis (Reinh. and Procamallanus (Procamallanus peraccuratus from Geophagus brasiliensis (Quoy & Gmard. and Cichlasoma facetum (Jenyns (Cichlaurus facetus as well as consider Procamallanus (Spirocamallanus probus Pinto & Fernandes, 1972, synonym of Procamallanus (Spirocamallanus inopinatus Travassos, Artigas & Pereira, 1928, after rechecking the type amount of the former. They also affix an unidentified sample as Procamallanus (Spirocamallanus sp.

  7. Morphological development of Corydoras aff. paleatus (Siluriformes, Callichthyidae and correlation with the emergence of motor and social behaviors

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    Daniel Rodríguez-Ithurralde

    2014-06-01

    Full Text Available Here we examine major anatomical characteristics of Corydoras aff. paleatus (Jenyns, 1842 post-hatching development, in parallel with its neurobehavioral evolution. Eleutheroembryonic phase, 4.3-8.8 days post-fertilization (dpf; 4.3-6.4 mm standard length (SL encompasses from hatching to transition to exogenous feeding. Protopterygiolarval phase (8.9-10.9 dpf; 6.5-6.7 mm SL goes from feeding transition to the commencement of unpaired fin differentiation, which marks the start of pterygiolarval phase (11-33 dpf; 6.8-10.7 mm SL defined by appearance of lepidotrichia in the dorsal part of the median finfold. This phase ends with the full detachment and differentiation of unpaired fins, events signaling the commencement of the juvenile period (34-60 dpf; 10.8-18.0 mm SL. Eleutheroembryonic phase focuses on hiding and differentiation of mechanosensory, chemosensory and central neural systems, crucial for supplying the larval period with efficient escape and nutrient detection-capture neurocircuits. Protopterygiolarval priorities include visual development and respiratory, digestive and hydrodynamic efficiencies. Pterygiolarval priorities change towards higher swimming efficacy, including carangiform and vertical swimming, necessary for the high social interaction typical of this species. At the end of the protopterygiolarval phase, simple resting and foraging aggregations are seen. Resting and foraging shoals grow in complexity and participant number during pterygiolarval phase, but particularly during juvenile period.

  8. Variação espaço-temporal da ictiofauna da zona de arrebentação da Praia do Cassino, Rio Grande do Sul, Brasil Spatiotemporal variation in the fish fauna of Praia do Cassino, Rio Grande do Sul, Brazil

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    Mauro Sergio Pinheiro Lima

    2009-09-01

    Full Text Available This study analyzes the spatiotemporal variation of the ichthyofauna of the surf zone of Praia do Cassino, municipality of Rio Grande (state of Rio Grande do Sul, Brazil from October 2005 to September 2006. Fishes were collected monthly and during daytime using a large beach seine net (30 m x 1.8 m, with 12 mm uniform mesh manufactured with monofilament nylon wire. Five hauls were conducted on each of three sampling sites: one near the jetties of Patos Lagoon and two located 5 km and 10 km south from the jetties, respectively. We caught 10,066 fishes, weighting 128,486 g, distributed in 37 species belonging to 18 families that are similar in species composition to the dominant fish fauna - Trachinotus marginatus (Cuvier, 1832, Atherinella brasiliensis (Quoy & Gaimard, 1825, Brevoortia pectinata (Jenyns, 1842, Mugil platanus (Gunther, 1880, Menticirrhus americanus (Linnaeus, 1758, Menticirrhus littoralis (Holbrook, 1847, and Oncopterus darwinii (Steindachner, 1874 - usually collected in the beaches of Rio Grande do Sul with a smaller net. The dominant size classes were between 50 and 100 mm TL and represent 43% of total catch. Based on CCA analysis we suggested that the ichthyofauna is primarily structured by seasonal variation in the physicochemical and environmental parameters and secondarily by the spatial difference between areas nearer ( approximately 10 km from the Patos Lagoon's jetties. The composition and dominance of the fish community of the surf zone of Cassino Beach changed little in the latest 20 years, indicating a possible stability of the system.

  9. Functional modularity in lake-dwelling characin fishes of Mexico.

    Science.gov (United States)

    Ornelas-García, Claudia Patricia; Bautista, Amando; Herder, Fabian; Doadrio, Ignacio

    2017-01-01

    Modular evolution promotes evolutionary change, allowing independent variation across morphological units. Recent studies have shown that under contrasting ecological pressures, patterns of modularity could be related to divergent evolution. The main goal of the present study was to evaluate the presence of modular evolution in two sister lacustrine species, Astyanax aeneus and A. caballeroi, which are differentiated by their trophic habits. Two different datasets were analyzed: (1) skull X-rays from 73 specimens (35 A. aeneus and 38 A. caballeroi) to characterize skull variation patterns, considering both species and sex effects. For this dataset, three different modularity hypotheses were tested, previously supported in other lacustrine divergent species; (2) a complete body shape dataset was also tested for four modularity hypotheses, which included a total of 196 individuals (110 Astyanax aeneus and 86 A. caballeroi). Skull shape showed significant differences among species and sex (P modularity hypothesis ranked first included three partitioning modules. While for the complete body dataset the best ranked hypothesis included two modules (head vs the rest of the body), being significant only for A. caballeroi.

  10. Effects of river damming in Neotropical piscivorous and omnivorous fish: feeding, body condition and abundances

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    Larissa Strictar Pereira

    Full Text Available ABSTRACT The increase in abundance of small-sized fishes is common after a reservoir is formed. There is an increase in the consumption of fish, from typically piscivorous fish to opportunistic species that take advantage of abundant resources. This study aims to evaluate the effects of diet changes induced by damming on the feeding activity and condition factor of typically piscivorous (Hoplias aff. malabaricus and Oligosarcus longirostris and opportunistic (Astyanax lacustris (ex Astyanax altiparanae and Pimelodus britskii . Sampling was conducted before and after the impoundment in the Iguaçu River in the region of Salto Caxias, Paraná State, Brazil. Stomach contents were analysed by the volumetric method. Feeding activity and body condition were inferred by the mean stomach repletion index and the mean condition factor. Typically piscivorous species presented a general tendency of decreased feeding activity and increased condition factor, while opportunistic species, presented a decrease in condition and feeding activity in the most affected sites. The increase in the condition factor of piscivorous fish suggests that these species benefit by the increased abundance of small size prey fish. Some opportunist species that do not have adjustments for the piscivorous diet, regardless of the intensity of consumption and resource availability, can suffer negative reflex when adopting a piscivorous diet.

  11. Nuclear DNA content determination in Characiformes fish (Teleostei, Ostariophysi from the Neotropical region

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    Carvalho Margarida Lima

    2002-01-01

    Full Text Available In the present study, nuclear DNA content was analyzed in 53 species of Characiformes fish from the Neotropical region. Diploid number ranged from 2n = 48 in Astyanax fasciatus, Gymnocorymbus ternetzi and Hyphessobrycon griemi to 2n = 102 in Potamorhina squamoralevis, with a modal number of 54 chromosomes. Nuclear DNA content ranged from 1.70 ± 0.04 pg of DNA per diploid nucleus in Acestrorhynchus pantaneiro to 3.94 ± 0.09 pg in Tetragonopterus chalceus. A general analysis showed a mean value of 2.9 pg of DNA per diploid nucleus. Very similar DNA content values were observed in the species of the family Cynodontidae which showed a variation of 3% between the two genera studied. Small variations were observed between populations of Gymnocorymbus ternetzi, Astyanax fasciatus and Moenkhausia sanctaefilomenae (Characidae, Tetragonopterinae. The subfamilies Tetragonopterinae and Acestrorhynchinae (Characidae presented the widest range, about 96%. Even in those families in which diploid number and karyotypic formulae were conserved such as the families Anostomidae, Curimatidae, and Prochilodontidae, episodes leading to losses or gains of genetic material became fixed in their evolutionary history.

  12. Habitat use and food partitioning of the fishes in a coastal stream of Atlantic Forest, Brazil

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    J. M. R. Aranha

    1998-12-01

    Full Text Available We analysed the fish assemblage in the "Mergulhão" stream (southern Brazil with underwater observations for habitat use, considering water depth, current velocity, bottom type, shadow from vegetation cover, distance of stream-edge, and vertical position. Stomach contents or foregut content samples of the most abundant species were collected from 26 species (10 families. The fish assemblage occupied the bottom stream. The similarity analysis of spatial occupation of species grouped four habitat use guilds: A "lambaris" (Astyanax sp. and Deuterodon langei, Characidium spp. (C. lanei and C. pterostictum and Rineloricaria kronei used the bottom in deep sites and waters with middle current; B Pimelodella pappenheimi and Corydoras barbatus used the bottom in sites with lower current; C Mimagoniates microlepis used the surface of the water column; and D Phalloceros caudimaculatus used shallow sites and waters without current. Species with few records were analysed descriptively. Diet similarity suggested seven trophic guilds: Microglanis sp. and Pimelodella pappenheimi: omnivorous/carnivorous guild; Corydoras barbatus: omnivorous/insectivorous guild; Characidium lanei: aquatic insectivorous guild, mainly aquatic insects; Mimagoniates microlepis: terrestrial insectivorous guild, mainly terrestrial insects; Deuterodon langei and Astyanax sp.: omnivorous/herbivorous guild; Rineloricaria kronei, Kronichthys subteres, Schizolecis guntheri, Hisonotus leucofrenatus and Pseudotothyris obtusa: herbivorous guild; and Phalloceros caudimaculatus: algivorous guild. When the guilds were similar, the species were generalists in diet and in habitat use.

  13. Integrative taxonomy detects cryptic and overlooked fish species in a neotropical river basin.

    Science.gov (United States)

    Gomes, Laís Carvalho; Pessali, Tiago Casarim; Sales, Naiara Guimarães; Pompeu, Paulo Santos; Carvalho, Daniel Cardoso

    2015-10-01

    The great freshwater fish diversity found in the neotropical region makes management and conservation actions challenging. Due to shortage of taxonomists and insufficient infrastructure to deal with such great biodiversity (i.e. taxonomic impediment), proposed remedies to accelerate species identification and descriptions include techniques that combine DNA-based identification and concise morphological description. The building of a DNA barcode reference database correlating meristic and genetic data was developed for 75 % of the Mucuri River basin's freshwater fish. We obtained a total of 141 DNA barcode sequences from 37 species belonging to 30 genera, 19 families, and 5 orders. Genetic distances within species, genera, and families were 0.74, 9.5, and 18.86 %, respectively. All species could be clearly identified by the DNA barcodes. Divergences between meristic morphological characteristics and DNA barcodes revealed two cryptic species among the Cyphocharax gilbert and Astyanax gr. bimaculatus specimens, and helped to identify two overlooked species within the Gymnotus and Astyanax taxa. Therefore, using a simplified model of neotropical biodiversity, we tested the efficiency of an integrative taxonomy approach for species discovery, identification of cryptic diversity, and accelerating biodiversity descriptions.

  14. Six new and one previously described species of Pseudorhabdosynochus (Monogenoidea, Diplectanidae) infecting the gills of groupers (Perciformes, Serranidae) from the Pacific coasts of Mexico and Panama.

    Science.gov (United States)

    Mendoza-Franco, Edgar F; Violante-González, Juan; Rojas Herrera, Agustín A

    2011-02-01

    Six new and 1 previously described species of Pseudorhabdosynochus (Diplectanidae) are described and/or reported from the gill lamellae of 5 serranid (Perciformes) fish species from the Pacific waters in Guerrero State of Mexico and Panama City, Panama. These species are Pseudorhabdosynochus guerreroensis n. sp. from the Pacific mutton hamlet Alphestes inmaculatus Breder (type host), rivulated mutton hamlet Alphestes multiguttatus (Günther), and spotted grouper Epinephelus analogus Gill from Mexico; Pseudorhabdosynochus urceolus n. sp. from the Pacific graysby Cephalopholis panamensis (Steindachner) from Taboga Island in Panama; Pseudorhabdosynochus spirani n. sp. from the starry grouper Epinephelus labriformis (Jenyns) from Mexico and the Perlas Archipelago and Taboga Island in Panama; Pseudorhabdosynochus fulgidus n. sp. from E. labriformis from Mexico and the Perlas Archipelago and Taboga Island (type locality) in Panama; Pseudorhabdosynochus tabogaensis n. sp. from E. labriformis from Mexico and the Perlas Archipelago and Taboga Island (type locality) in Panama; Pseudorhabdosynochus anulus n. sp. from E. labriformis from Mexico and Taboga Island (type locality) in Panama; and Pseudorhabdosynochus amplidiscatum (Bravo-Hollis, 1954) Kritsky and Beverley-Burton, 1986 from E. analogus and E. labriformis from Mexico and the Perlas Archipelago and Taboga Island in Panama. All new species are mainly distinguished from other species of the genus by the shape and size of the sclerotized vagina and haptoral structures. The present specimens of Alphestes, Cephalopholis, and Epinephelus spp. represent new host records and Panama represents a new geographic record for species of Pseudorhabdosynochus. The apparent common feature supporting a close similarity of these diplectanids is a single, secondary ejaculatory bulb with thickened wall.

  15. A Bayesian analysis of the parasitic ecology in Jenynsia multidentata(Pisces: Anablepidae

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    Martin M. Montes

    2017-09-01

    Full Text Available ABSTRACT Jenynsia multidentata Jenyns, 1842 (one-sided livebearers are euryhaline viviparous fish of small size, used in the laboratory experiment, important as resource for biological control of mosquito’s larva and a key species to recover eutrophic lakes. Works have been published dealing with parasite biodiversity of this host, but little has been studied about the parasite community ecology. From early 2009 to ends of 2010 specimens of J. multidentata were collected from two places, the Salado Relief Channel (S.R.C. on Samborombón Bay and the Sauce Chico River near to the city of Bahia Blanca (B.B.. All fish were sexed, measured and grouped into sizes/age classes. The fishes from both sites harbored 16 parasitic species: nine digenean, one monogenean, one metacestode, one acanthocephalan, two nematode and two copepods. Lecithaster confusus Odhner, 1905, the metacercariae Hemiuridae gen. sp. indet., metacercariae Thylodelphys sp. (inside the eye, Glossocercus sp. nematode L4 (intestine and Ergasilus sieboldii Nordmann, 1832 are new records for the host. The high number of larval stages made of this fish a link between micro and macroecosystems. The size 2 had the higher biodiversity in both sites, which could be the most suitable age to store the maximal number of parasite of the environment and have a more equitability in their distribution on the host. In B.B. some parasites had higher prevalence and mean abun dance due to the small size of the waterbody compared with the S.R.C. Despite that, in S.R.C. exist a higher specific richness and biodiversity due the daily flow of saline and freshwater and proximity of the sample site to the mouth of the channel in the bay. This is the first approximation to an analysis of the parasitic ecology on this host.

  16. Evaluation of waterborne exposure to oil spill 5 years after an accident in Southern Brazil.

    Science.gov (United States)

    Silva, C A; Oliveira Ribeiro, C A; Katsumiti, A; Araújo, M L P; Zandoná, E M; Costa Silva, G P; Maschio, J; Roche, H; Silva de Assis, H C

    2009-02-01

    Fish (Astyanax sp.) were exposed to water samples from the Arroio Saldanha, locality of an oil spill, and the Barigui River (upstream and downstream of the confluence of the river and Arroio Saldanha), Brazil. Histopathological and biochemical biomarkers, as acetylcholinesterase (AchE), ethoxyresorufin-O-deethylase (EROD), catalase (CAT), glutathione-S-transferase (GST) activities, lipid peroxidation (LPO) levels, and amounts of polynuclear aromatic hydrocarbon residues (PAHs) in bile were evaluated. PAHs, metals, and surfactants were investigated in the water samples. CAT and GST activities increased in the Arroio Saldanha sample, whereas CAT activity and LPO levels were increased in the upstream and downstream sites. The results suggested a toxic action of the free radicals and disturbance of the antioxidant defense mechanisms. However, the EROD and AchE activities were not affected. Histopathology studies showed severe lesions. The oil is still bioavailable to biota, moreover, other pollution sources continue to affect the water in the Barigui River.

  17. Feeding association between benthic and nektonic Neotropical stream fishes

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    Fabrício Barreto Teresa

    Full Text Available Following behaviour among Neotropical stream fishes have been scarcely reported. This type of feeding association was observed in a small stream in the upper rio Paraná system between the catfish, Aspidoras fuscoguttatus, acting as a nuclear species, and Knodus moenkhausii, Poecilia reticulata, and Astyanax altiparanae as follower species. Aspidoras fuscoguttatus individuals dug in the bottom during feeding, causing sediment suspension. Their followers picked food items in the "cloud" of suspended particles. Food items of sediment are no longer consumed by the catfish when in suspension, but are still available for K. moenkhausii, P. reticulata and A. altiparanae. Following behaviour is an alternative feeding tactic for these species, which reinforces the general idea of behavioural plasticity among follower species.

  18. Conspecific and heterospecific alarm substances induce behavioral responses in juvenile catfish Rhamdia quelen

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    Carina Vogel

    2017-04-01

    Full Text Available ABSTRACT The recognition of chemical information indicating the presence of a predator is very important for prey survival. In this study we tested antipredator behavioral response of juvenile silver catfish (Rhamdia quelen against predator odor released by two different potential predators, Hoplias malabaricus and the snake Helicops infrataeniatus, and alarm cues and disturbance cues released by conspecifics and by non-predator species, Megaleporinus obtusidens and Astyanax lacustris. We used juvenile catfish that were naive to predators. The trials consisted of a 10-min prestimulus and a 10-min post-stimulus observation period. The behavioral response displayed by silver catfish exposed to alarm cues comprised a decrease in shelter use and an increase in locomotion, and also a longer latency period before feeding. Our results showed that juvenile silver catfish can perceive chemical cues released by predators, heterospecifics and conspecifics.

  19. Alimentação de Oligosarcus longirostris Menezes & Gèry (Osteichthyes, acestrorhynchinae do Reservatório de Salto Segredo, Paraná, Brasil Feeding of Oligosarcus longirostris Menezes & Gèry (Osteichthyes, acestrorhynchinae of the Salto Segredo Reservoir, Paraná, Brazil

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    Ana Maria Gealh

    1998-12-01

    Full Text Available In the feeding study of O. longirostris Menezes & Gèry, 1983, 211 stomachs from fish caught between March 1993 and February 1994 were analysed. Diet composition was analysed by the index of relative importance which deals with the numerical and gravimetric occurrence frequency. Results indicated that the species is piscivorous and its preferential food consisted oíAslyanax sp. 2. It was also found that Astyanax sp. 3 became an important food item, depending on the site of capture and its availability. Availability of prey seems to have a strong influence on the diet of O. longirostris. This same tendency has been observed during the different seasons of the year. Ontogenetic changes have also been found in the basic diet.

  20. Structure and integrity of fish assemblages in streams associated to conservation units in Central Brazil

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    Thiago Belisário d'Araújo Couto

    Full Text Available This study aims to characterize the spatial and seasonal distribution of the fish assemblage and evaluate the integrity of streams in a sustainable use area that includes integral protection conservation units in Distrito Federal, Central Brazil (Cerrado biome. For the study, 12 stretches of 8 streams were sampled in 2008 (dry season and 2009 (wet season. For that evaluation was estimated the Physical Habitat Index (PHI, vegetation cover (VC, pH, dissolved oxygen, turbidity, and conductivity. We recorded 22 species, about eight undescribed species, by a total of 2,327 individuals. The most representative families in number of species were Characidae (31.8%, Loricariidae (31.8%, and Crenuchidae (13.6%. Knodus moenkhausii was the most abundant species with 1,476 individuals, added to Astyanax sp., Phalloceros harpagos, and Hasemania sp. they represent over 95% of the total abundance. The species Astyanax sp. (occurring in 79.2% of the stretches and K. moenkhausii (50.0% were considered constant in both seasons. The longitudinal gradient (River Continuum exerts a strong influence on the studied assemblage. According to CCA, the variables that structure the fish assemblage are based on aspects related to water volume and habitat complexity. No seasonal variation in richness, diversity, abundance, and mass were detected. A cluster analysis suggests a separation of species composition between the stretches of higher and lower orders, which was not observed for seasonality. The streams were considered well preserved (mean PHI 82.9±7.5%, but in some stretches were observed anthropogenic influence, detected in the water quality and, mainly, on the riparian vegetation integrity. The exotic species Poecilia reticulata was sampled in the two stretches considered most affected by anthropogenic activities by PHI, conductivity, and VC.

  1. Distribution of fish assemblages in Lajes Reservoir, Rio de Janeiro, Brazil

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    F. G. ARAÚJO

    Full Text Available Spatial distribution of fish assemblages in Lajes Reservoir, a 30 km² impoundment in Rio de Janeiro State (Lat. 22º42'-22º50'S; Long. 43º53'-44º05'W was assessed to detect patterns of available habitat use by the fish. A standardized monthly sampling program was carried out from January to December 1994 at three zones of the reservoir (upper, near tributary mouths; middle; and lower, near the dam. Fishes were caught by gillnets, (50 m long, 3 m height, with mesh ranging having from 25 to 45 mm between knots, submerged during 12 hours. A total of 5,089 fishes were collected comprising 15 species, 14 genera and 9 families. Loricariichthys spixii, Astyanax bimaculatus, Parauchenipterus striatulus, Astyanax fasciatus parahybae, Oligosarchus hepsetus, Rhamdia parahybae, Hypostomus affinis, and Geophagus brasiliensis were the most abundant species, each contributing above 1% of the total number. Loricariichthys spixii was the dominant species, contributing over 80% of total number and biomass. Fish abundance, number of species, and biomass were higher in the upper zone, but differences from this overall pattern were shown by some species. Loricariichthys spixii and Rhamdia parahybae were more abundant in the upper zone, while all other species showed no differences in their abundance among the zones. Seasonal environmental variables of temperature, pH, transparency, and water level did not show a clear association with fish occurrence. Most fish used the different zones of the reservoir with no clear sign of spatial separation. High dominance of L. spixii, reduced abundance of reolific species Leporinus copelandii and Cyphocharax gilberti, and presence of introduced species such as Cichla monoculus and Tilapia rendalli are indications of antropic effects in the fish community.

  2. Evidence for herbaceous seed dispersal by small-bodied fishes in a Pantanal seasonal wetland

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    RML Silveira

    Full Text Available We analysed the germination of seeds after their passage through the digestive tract of small floodplain fishes. Samples were collected in five open flooded fields of the northern Pantanal in March 2011. All fishes were sacrificed and their intestinal contents were removed. The fecal material was weighed and stored at 4°C in a GF/C filter wrapped in aluminum foil. The material was then transferred to a receptacle containing sterilised soil from the sampling area. The fecal samples were kept in a germination chamber for 68 days and then transferred to a greenhouse for another 67 days. We collected a total of 45 fish species and 1014 individuals which produced a total amount of 32g of fresh fecal mass and 11 seedlings. We were able to identify six seedlings: two Banara arguta, two Steinchisma laxa, one Hymenachne amplexicaulis and one Luziola sp.. The fish species that produced samples with seedlings were Astyanax assuncionensis, Metynnis mola, Plesiolebias glaucopterus, Acestrorhyncus pantaneiro and Anadoras wendelli. With the exception of B. arguta the remaining plant species and all fish species were not known to be associated with the seed dispersal process of these plants. We found a ratio of 0.435 seedlings.g–1 of fresh fecal material, which is 100 times higher than the amount of seedlings encountered in fresh soil mass (92,974 grams in seed bank studies conducted in the same study area. In particular, Astyanax assuncionensis and Metynnis mola were among the most frequent and most abundant fish taxa in the area. Together with the high seed concentration in the fish fecal material, this evidence allows us to conclude that such fish species may play an important role in seed dispersal in the herbaceous plants of the Pantanal.

  3. Evidence for herbaceous seed dispersal by small-bodied fishes in a Pantanal seasonal wetland.

    Science.gov (United States)

    Silveira, R M L; Weiss, B

    2014-08-01

    We analysed the germination of seeds after their passage through the digestive tract of small floodplain fishes. Samples were collected in five open flooded fields of the northern Pantanal in March 2011. All fishes were sacrificed and their intestinal contents were removed. The fecal material was weighed and stored at 4°C in a GF/C filter wrapped in aluminum foil. The material was then transferred to a receptacle containing sterilised soil from the sampling area. The fecal samples were kept in a germination chamber for 68 days and then transferred to a greenhouse for another 67 days. We collected a total of 45 fish species and 1014 individuals which produced a total amount of 32 g of fresh fecal mass and 11 seedlings. We were able to identify six seedlings: two Banara arguta, two Steinchisma laxa, one Hymenachne amplexicaulis and one Luziola sp.. The fish species that produced samples with seedlings were Astyanax assuncionensis, Metynnis mola, Plesiolebias glaucopterus, Acestrorhyncus pantaneiro and Anadoras wendelli. With the exception of B. arguta the remaining plant species and all fish species were not known to be associated with the seed dispersal process of these plants. We found a ratio of 0.435 seedlings.g-1 of fresh fecal material, which is 100 times higher than the amount of seedlings encountered in fresh soil mass (92,974 grams) in seed bank studies conducted in the same study area. In particular, Astyanax assuncionensis and Metynnis mola were among the most frequent and most abundant fish taxa in the area. Together with the high seed concentration in the fish fecal material, this evidence allows us to conclude that such fish species may play an important role in seed dispersal in the herbaceous plants of the Pantanal.

  4. DNA barcodes discriminate freshwater fishes from the Paraíba do Sul River Basin, São Paulo, Brazil.

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    Pereira, Luiz H G; Maia, Gláucia M G; Hanner, Robert; Foresti, Fausto; Oliveira, Claudio

    2011-10-01

    Considering the promising use of DNA barcoding for species identification, the importance of the freshwater fish fauna of the Paraíba do Sul River Basin, and its advanced stage of degradation, the present study evaluated the effectiveness of DNA barcoding to identify the fish species in this basin. A total of 295 specimens representing 58 species belonging to 40 genera, 17 families, and 5 orders were sequenced. The DNA barcodes discriminated all species analyzed without ambiguity. The results showed a pronounced difference between conspecific and congeneric pair-wise sequence comparisons, demonstrating the existence of a "barcode gap" for the species analyzed. The nearest-neighbor distance analysis showed only three cases with Kimura two-parameter values lower than a 2% divergence threshold. However, the patterns of divergence observed in each case remained sufficient to discriminate each species, revealing the accuracy of DNA barcoding even cases with relatively low genetic divergence. At the other extreme, three species displayed high genetic sequence divergence among conspecifics. For two cases, Characidium alipioi and Geophagus proximus, barcoding proved effective at flagging possible new species. For another case, Astyanax bimaculatus, the use of DNA barcoding of the comparison of shared freshwater fish fauna between different basins revealed itself as highly useful in disclosing that the previously identified A. bimaculatus "cluster A" probably represents the species Astyanax altiparanae. The present study is among the first to assess the efficiency of barcoding for the Brazilian freshwater fishes. The results demonstrate the utility of barcoding to identify the fauna from this basin, contribute to an enhanced understanding of the differentiation among species, and to help flag the presence of overlooked species.

  5. Movement patterns of stream-dwelling fishes from Mata Atlântica, Southeast Brazil

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    Rosana Mazzoni

    2012-12-01

    Full Text Available The identification of mechanisms of spatial-temporal variation, obtained from the quantification of natural populations, is a central topic of ecological research. Despite its importance to life-history theory, as well as to conservation and management of natural populations, no studies concerning movement patterns and home range of small stream-dwelling fishes from Brazilian rain forests are known. In the present study we aimed to describe the longitudinal pattern of long distance movement as well as local patterns of short movement (daily home-range of fishes from a Mata Atlântica stream from Southeast Brazil. We gathered information about movement dynamic in order to discuss the relationship between swimming ability, fish morphology and home range. Long distance movement data were obtained in a mark-recapture experiment held in the field between June and September - 2008, on five sites along the Ubatiba stream. For this study, we had one day to mark fishes, on June-19, and 14 events for recapture. Considering the ten species that inhabit the study area, our study showed that four species: Astyanax janeiroensis, Astyanax hastatus, Parotocinclus maculicauda and Pimelodella lateristriga, moved at least 6 000m in 60 days. The other six species did not present long distance movements, as they were recaptured in the same site 90 days after being marked. For short distance study, movement data were obtained in one mark-recapture experiment held in a 100m long site subdivided into five 20m stretches where fishes were marked with different elastomer colours. We marked 583 specimens that after recapture showed two groups of different movement patterns. The first group was called “Long Movement Group” and the second one was called “Short Movement Group”. The Long Movement Group showed, on average, 89.8% of moving fishes and 10.2% of non moving fishes, against 21.3% and 78.7%, respectively, for the Short Movement Group. It was concluded that

  6. Estrutura da comunidade de peixes da represa “Lago del Fuerte”, Tandil, Argentina Fish community structure of “Lago del Fuerte” reservoir, Tandil, Argentina

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    Fabián Grosman

    1999-07-01

    Full Text Available A represa “Lago del Fuerte” constitui um centro de atividades recreativas onde a pesca esportiva do peixe-rei Odontesthes bonariensis, espécie introduzida para tal fim, tem um lugar de importância. Este trabalho tem como objetivo determinar a estrutura da comunidade de peixes, sua distribuição, principais relações tróficas e os parâmetros demográficos da população do peixe-rei. A vegetação marginal submersa da represa forma um ambiente favorável para o desenvolvimento dos peixes de pequeno porte; em compensação, o peixe-rei utiliza as águas livres. A competição interespecífica é reduzida pela segregação dos habitats e/o dos nichos tróficos. Astyanax eigenmanniorum é principalmente herbívoro; O. bonariensis, zooplanctófago e Cichlasoma facetum, onívoro. Existem relações muito estreitas entre os diferentes níveis energéticos presentes no sistema. A disponibilidade de zooplâncton regula os parâmetros da população do peixe-rei, o qual regula a composição do mesmo através da predação; na ausência de ictiófagos, o pescador é o responsável por influir nas variações demográficas do peixe-rei.Lago del Fuerte reservoir is a leisure center where sport fishing of silverside (Odontesthes bonariensis, a species stocked for this purpose, is very important. The objective of this paper is to determine the current fish community structure in this reservoir, their distribution, main trophic relationships and demographic parameters of the silverside population. The demersed vegetation present in the littoral region shapes favourable microenvironments for the development of shorter fish species; the silverside population use the pelagic region. The interspecific competition is reduced by means of habitat and/or trophic niche segregation. Astyanax eigenmanniorum is principally herbivorous; O. bonariensis is principally zooplanktophagous, and Cichlasoma facetum has a generalistic diet. There are very strong

  7. The fish fauna in tropical rivers: The case of the Sorocaba river basin, SP, Brazil

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    Welber Senteio Smith

    2003-09-01

    Full Text Available A survey was carried out on the fish species in the Sorocaba River basin, the main tributary of the left margin of the Tietê River, located in the State of São Paulo, Brazil. The species were collected with gill nets. After identification of the specimens, their relative abundance, weight and standard length were determined. Up to the present moment there are not any studies that focus this subject in this hydrographic basin. Fifty-three species, distributed in eighteen families and six orders were collected. Characiformes were represented by twenty-eight species, Siluriformes by seventeen species, the Gymnotiformes by three species, Perciformes and Cyprinodontiformes by two species, and the Synbranchiformes by one species. Among the collected species there were two exotic. The most abundant species were Astyanax fasciatus and Hypostomus ancistroides. In relation to total weight the most representative species were Hoplias malabaricus and Hypostomus ancistroides. Cyprinus carpio, Prochilodus lineatus, Schizodon nasutus and Hoplias malabaricus were the most representative species in relation to average weight. Largest standard length were recorded for Sternopygus macrurus, Steindachnerina insculpta, Eigenmannia aff. virescens and Cyprinus carpioSe realizó un análisis de las especies de peces de la cuenca del Río Sorocaba, el principal tributario de la margen izquierda del Río Tietê, localizado en el estado de Sao Paulo, Brasil. Las especies fueron recolectadas con redes agalleras. Luego de la identificación de los especímenes, fue determinada su abundancia relativa, peso, y longitud estandar. Hasta el presente, no hay ningún otro estudio que analice estos aspectos en dicha cuenca hidrográfica. Fueron recolectados 55 especies, distribuidas en 18 familias y 6 ordenes. Los Characiformes estuvieron representados por 28 especies, Siluriformes por 17 especies, Gymnotiformes por 3 especies, Perciformes y Cyprinodontiformes por 2 especies, y

  8. Reproductive strategies and genetic variability in tropical freshwater fish

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    Maria Dolores Peres Lassala

    2007-01-01

    Full Text Available We estimated the genetic variability of nine fish species from the Brazilian upper Paraná River floodplain (Astyanax altiparanae, Hoplias malabaricus, Leporinus lacustris, Loricariichthys platymetopon, Parauchenipterus galeatus, Pimelodus maculatus, Rhaphiodon vulpinus, Roeboides paranensis and Serrasalmus marginatus based on data for 36 putative allozyme loci obtained using corn starch gel electrophoresis of 13 enzymatic systems: aspartate aminotransferase (EC 2.6.1.1, acid phosphatase (EC 3.1.3.2, esterase (EC 3.1.1.1, glycerol-3-phosphate dehydrogenase (EC 1.1.1.8, glucose-6-phosphate dehydrogenase (EC 1.1.1.49, glucose-6-phosphate isomerase (EC 5.3.1.9, Iditol dehydrogenase (EC 1.1.1.14, isocitrate dehydrogenase - NADP+ (EC 1.1.1.42, L-lactate dehydrogenase (EC 1.1.1.27, malate dehydrogenase (EC 1.1.1.37, malate dehydrogenase-NADP+ (EC 1.1.1.40, phosphoglucomutase (EC 5.4.2.2 and superoxide dismutase, (EC 1.15.1.1. The mean expected heterozygosity varied from zero to 0.147. When data from the literature for 75 species of tropical fish were added to the nine species of this study, the heterozygosity values differed significantly among the groups of different reproductive strategies. The highest mean heterozygosity was for the non-migratory without parental care, followed by the long-distance migratory, and the lowest mean was for the non-migratory with parental care or internal fecundation.

  9. Sport fishing in Cachoeira de Emas in Mogi-Guaçu River, State of São Paulo, Brazil

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    J. Peixer

    Full Text Available Sport fishing is an important leisure activity in many countries. It directly and indirectly generates income and jobs for millions of people. In some places, its landing outstrips production from professional fishing but this fact is not always taken into account in the establishment of management actions. In the area of Cachoeira (Waterfall de Emas there are reports of intense fishing since the 20's. The objective of this paper is to identify the profile of the sporting fishers who frequent this place and to characterise this fishing. From February to October of 2006, we interviewed 107 sporting fishers that visited Cachoeira. We describe the fishing and the socio-economic status of the sport fishers. Most of the fishers are men, coming from the state of São Paulo, with a mean family income of US$ 1,212.3 (R$ 2,558.10, US$ 1 = R$ 2.11, July/2007, being aged 50.2 years old on average. A large amount of them (49.5% only have incomplete first grade education. The main captured species are curimba Prochilodus lineatus, mandi Pimelodus maculatus, P. heraldoi, Pimelodella spp., lambari Astyanax fasciatus, A. schubarti, A. altiparanae, Roeboides paranensis and piava Leporinus lacustris, L. friderici, L. octofasciatus. Fishers have had a strong connection with this place for many years and even with low captures (2.8 kg/day, they are quite satisfied.

  10. Monogeneans of freshwater fishes from cenotes (sinkholes) of the Yucatan Peninsula, Mexico.

    Science.gov (United States)

    Mendoza-Franco, E F; Scholz, T; Vivas-Rodríguez, C; Vargas-Vázquez, J

    1999-01-01

    During a survey of the parasites of freshwater fishes from cenotes (sinkholes) of the Yucatan Peninsula the following species of monogeneans were found on cichlid, pimelodid, characid and poeciliid fishes: Sciadicleithrum mexicanum Kritsky, Vidal-Martinez et Rodriguez-Canul, 1994 from Cichlasoma urophthalmus (Günther) (type host), Cichlasoma friedrichsthali (Heckel), Cichlasoma octofasciatum (Regan), and Cichlasoma synspilum Hubbs, all new host records; Sciadicleithrum meekii Mendoza-Franco, Scholz et Vidal-Martínez, 1997 from Cichlasoma meeki (Brind); Urocleidoides chavarriai (Price, 1938) and Urocleidoides travassosi (Price, 1938) from Rhamdia guatemalensis (Günther); Urocleidoides costaricensis (Price et Bussing, 1967), Urocleidoides heteroancistrium (Price et Bussing, 1968), Urocleidoides anops Kritsky et Thatcher, 1974, Anacanthocotyle anacanthocotyle Kritsky et Fritts, 1970, and Gyrodactylus neotropicalis Kritsky et Fritts, 1970 from Astyanax fasciatus; and Gyrodactylus sp. from Gambusia yucatana Regan. Urocleidoides chavarriai, U. travassosi, U. costaricensis, U. heteroancistrium, U. anops, Anacanthocotyle anacanthocotyle and Gyrodactylus neotropicalis are reported from North America (Mexico) for the first time. These findings support the idea about the dispersion of freshwater fishes and their monogenean parasites from South America through Central America to southeastern Mexico, following the emergence of the Panamanian isthmus between 2 and 5 million years ago.

  11. Diet of fish (Characiformes: Characidae during early developmental stages in the Upper Paraná river basin, Brazil

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    Claudemir Martins Soares

    2017-11-01

    Full Text Available This study analyzed the diet during early developmental stages of Astyanax lacustris (AA, Piaractus mesopotamicus (PM, Megaleporinus obtusidens (MO and Prochilodus lineatus (PL, under experimental conditions. Fish larvae, 350 of each species, were stocked separately in 16 fiber-cement tanks (500 L, from which, three larvae of each species were collected every three days, for 36 days. Tanks were fertilized (1.5 g NPK-7: 14: 8 and had 50% of the surface with macrophytes. Larvae were grouped in age classes = I: 5 to 11, II: 14 to 20, III: 23 to 29 and IV: 32 to 38 days and, dissected for analysis of the digestive tract. Methodologies of dominance, frequency of occurrence and points of food items were used. For AA and PM larvae, measurements were taken for the number and size of organisms to determine the percent participation in biovolume. Changes in diets of larvae in different age classes were found as well as between different species, with the same age. Rotifers were dominant in the content of digestive tracts of all species at Class I, and the larvae diets became more distinct with increasing age, in which AA consumed mainly rotifers, PM, larger organisms (mainly cladocerans, PL, algae (diatoms as the main item and PP with a more diversified diet (rotifers, ostracodes and algae. In conclusion, early stages of these species presented distinct diets, undergoing remarkable changes in the first 38 days of life.

  12. Water quality assessment of the Sinos River - RS, Brazil.

    Science.gov (United States)

    Steffens, C; Klauck, C R; Benvenuti, T; Silva, L B; Rodrigues, M A S

    2015-12-01

    Worldwide environmental pollution is increasing at the same rate as social and economic development. This growth, however, is disorganized and leads to increased degradation of water resources. Water, which was once considered inexhaustible, has become the focus of environmental concerns because it is essential for life and for many production processes. This article describes monitoring of the water quality at three points along the Sinos River (RS, Brazil), one in each of the upper, middle and lower stretches. The points were sampled in 2013 and again in 2014. The water samples were analyzed to determine the following physical and chemical parameters plus genotoxicity to fish: metals (Cr, Fe, Al), chemical oxygen demand, biochemical oxygen demand, chlorides, conductivity, total suspended solids, total phosphorous, total and fecal coliforms, pH, dissolved oxygen, turbidity, total Kjeldahl nitrogen nitrate and ammoniacal nitrogen. Genotoxicity was tested by exposing individuals of the species Astyanax jacuhiensis to water samples and then comparing them with a control group exposed to water from the public water supply. The results confirmed the presence of substances with genotoxic potential at the sample points located in the middle and lower stretches of the river. The results for samples from the upper stretch, at P1, did not exhibit differences in relation to the control group. The physical and chemical analyses did not detect reductions in water quality in the lower stretch, as had been expected in view of the large volumes of domestic and industrial effluents discharged into this part of the river.

  13. Manipulation of Fgf and Bmp signaling in teleost fishes suggests potential pathways for the evolutionary origin of multicuspid teeth

    Science.gov (United States)

    Jackman, William R; Davies, Shelby H; Lyons, David B; Stauder, Caitlin K; Denton-Schneider, Benjamin R; Jowdry, Andrea; Aigler, Sharon R; Vogel, Scott A; Stock, David W

    2014-01-01

    Teeth with two or more cusps have arisen independently from an ancestral unicuspid condition in a variety of vertebrate lineages, including sharks, teleost fishes, amphibians, lizards, and mammals. One potential explanation for the repeated origins of multicuspid teeth is the existence of multiple adaptive pathways leading to them, as suggested by their different uses in these lineages. Another is that the addition of cusps required only minor changes in genetic pathways regulating tooth development. Here we provide support for the latter hypothesis by demonstrating that manipulation of the levels of Fibroblast growth factor (Fgf) or Bone morphogenetic protein (Bmp) signaling produces bicuspid teeth in the zebrafish (Danio rerio), a species lacking multicuspid teeth in its ancestry. The generality of these results for teleosts is suggested by the conversion of unicuspid pharyngeal teeth into bicuspid teeth by similar manipulations of the Mexican Tetra (Astyanax mexicanus). That these manipulations also produced supernumerary teeth in both species supports previous suggestions of similarities in the molecular control of tooth and cusp number. We conclude that despite their apparent complexity, the evolutionary origin of multicuspid teeth is positively constrained, likely requiring only slight modifications of a pre-existing mechanism for patterning the number and spacing of individual teeth. PMID:25098636

  14. La expiación femenina de la guerra en Las Troyanas de Eurípides

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    Ethel Beatriz Junco de Calabrese

    2016-07-01

    Full Text Available En Las Troyanas de Eurípides observamos la imagen de la guerra en la conciencia occidental como matriz de futuras identidades ante dos claves: el distanciamiento de lo divino y la reacción femenina. La lógica de la guerra se revierte en la virtud purificatoria de la madre, que sostiene su capacidad de dar vida mediante la compasión, concretada en el entierro, acto central de la obra. La sepultura por antonomasia de Troya, corporizada en el escudo de Héctor que velará por Astianacte, es signo de reconciliación por el sacrificio y reclamo a través de los siglos de la superioridad de la paz. In The Trojan Women by Euripides we observe the image of war in Western consciousness as the matrix of future identities facing two keys: the spacing of the divine and the female reaction. The logic of war is reversed in the purification virtue of the mother, holding her ability to give life through compassion, embodied in the burial, central act of the play. The burial for antonomasia of Troy, embodied in the shield of Hector to ensure Astyanax, is a sign of reconciliation by sacrifice and claim through the centuries of the superiority of peace.

  15. Integrating ontogenetic shift, growth and mortality to determine a species' ecological role from isotopic signatures.

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    Nelson F Fontoura

    Full Text Available Understanding species linkages and energy transfer is a basic goal underlying any attempt at ecosystem analysis. Although the first food-web studies were based on gut contents of captured specimens, the assessment of stable isotopes, mainly δ13C and δ15N, has become a standard methodology for wide-range analyses in the last 30 years. Stable isotopes provide information on the trophic level of species, food-web length, and origin of organic matter ingested by consumers. In this study, we analyzed the ontogenetic variability of δ13C and δ15N obtained from samples of three Neotropical fish species: silver sardine (Lycengraulis grossidens, n=46, white lambari (Cyanocharax alburnus, n= 26, and the red-tail lambari (Astyanax fasciatus, n=23 in Pinguela Lagoon, southern Brazil. We developed a new metric, called the Weighted Isotopic Signature (φ 15N or φ 13C, ‰, that incorporates ontogenetic variability, body growth, and natural mortality into a single number.

  16. Water quality assessment of the Sinos River – RS, Brazil

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    C. Steffens

    Full Text Available Worldwide environmental pollution is increasing at the same rate as social and economic development. This growth, however, is disorganized and leads to increased degradation of water resources. Water, which was once considered inexhaustible, has become the focus of environmental concerns because it is essential for life and for many production processes. This article describes monitoring of the water quality at three points along the Sinos River (RS, Brazil, one in each of the upper, middle and lower stretches. The points were sampled in 2013 and again in 2014. The water samples were analyzed to determine the following physical and chemical parameters plus genotoxicity to fish: metals (Cr, Fe, Al, chemical oxygen demand, biochemical oxygen demand, chlorides, conductivity, total suspended solids, total phosphorous, total and fecal coliforms, pH, dissolved oxygen, turbidity, total Kjeldahl nitrogen nitrate and ammoniacal nitrogen. Genotoxicity was tested by exposing individuals of the species Astyanax jacuhiensis to water samples and then comparing them with a control group exposed to water from the public water supply. The results confirmed the presence of substances with genotoxic potential at the sample points located in the middle and lower stretches of the river. The results for samples from the upper stretch, at P1, did not exhibit differences in relation to the control group. The physical and chemical analyses did not detect reductions in water quality in the lower stretch, as had been expected in view of the large volumes of domestic and industrial effluents discharged into this part of the river.

  17. Induced reproduction in a migratory teleost species by water level drawdown

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    Chayrra Chehade

    Full Text Available Captive reproduction is one of the problems faced in aquaculture requiring the manipulation of environmental factors and/or hormonal treatment. Thus, we seek to verify experimentally which gonadal changes were present in mature individuals of Astyanax altiparanae arising from decreased water level. Collections were made every four hours, initiated four hours before and finished 28 hours after stimulation, at the Fish Farming Station of Companhia Energética de São Paulo, São Paulo, Brazil. The gonads were analyzed by light microscopy. The females had ovaries in the spawning capable phase until 12h; in 16h, in a more advanced stage of spawning capable phase; and, from 20h, in the regressing phase. Males had testes in the spawning capable phase until 8h; in 12h, in a more advanced stage of spawning capable phase; and, from 16h, the return to the spawning capable phase. The morphological description was corroborated by the proportion of cell classes. Females presented variation on the gonadosomatic index, but it was not found an emptying of the gonad for neither sex. The process of inducing reproduction with water level drawdown was considered satisfactory, since both sexes presented a reduction in the number of mature gametes at the end of the sample period.

  18. Habitat preferences of common native fishes in a tropical river in Southeastern Brazil

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    Marcus Rodrigues da Costa

    Full Text Available We determined in this study the habitat preferences of seven native fish species in a regulated river in Southeastern Brazil. We tested the hypothesis that fishes differ in habitat preference and that they use stretches of the river differing in hydraulic characteristics and substrate type. We surveyed fishes in four 1-km long river stretches encompassing different habitat traits, where we also measured water depth, velocity, and substrate type. We investigated preference patterns of four Siluriformes (Loricariichthys castaneus, Hoplosternum littorale, Pimelodus maculatus, and Trachelyopterus striatulus and three Characiformes (Astyanax aff. bimaculatus, Oligosarcus hepsetus, and Hoplias malabaricus, representing approximately 70% of the total number of fishes and 64% of the total biomass. We classified fishes into four habitat guilds: (1 a slow-flowing water guild that occupied mud-sand substrate, composed of two Siluriformes in either shallow ( 8 m, L. castaneus waters; (2 a run-dwelling guild that occurs in deep backwaters with clay-mud substrate, composed of the Characiformes A. aff. bimaculatus and O. hepsetus; (3 a run-dwelling guild that occurs in sandy and shallow substrate, composed of T. striatulus; and (4 a fast-flowing guild that occurs primarily along shorelines with shallow mud bottoms, composed of H. malabaricus and P. maculatus. Our hypothesis was confirmed, as different habitat preferences by fishes appear to occur in this regulated river.

  19. Sedentary behavior as a factor in determining lateral line contributions to rheotaxis.

    Science.gov (United States)

    Bak-Coleman, Joseph; Coombs, Sheryl

    2014-07-01

    Rheotaxis is a robust, multisensory behavior with many potential benefits for fish and other aquatic animals. Visual (optic flow) cues appear to be sufficient for rheotaxis, but other sensory cues can clearly compensate for the loss of vision. The role of various non-visual sensory systems, in particular the flow-sensing lateral line, is poorly understood, largely because of widely varying methods and sensory conditions for studying rheotaxis. Here, we examine how sedentary behavior under visually deprived conditions affects the relative importance of lateral line cues in two species: one that is normally sedentary (the three-lined corydoras, Corydoras trilineatus) and one that normally swims continuously along the substrate (the blind cavefish, Astyanax mexicanus). No effect of lateral line disruption on rheotactic performance was found in blind cavefish, which were significantly more mobile than three-lined corydoras. By contrast, rheotaxis was significantly impaired at low, but not high, flow speeds in lateral-line-disabled corydoras. In addition, lateral-line-enabled corydoras were characterized by decreased mobility and increased rheotactic performance relative to lateral-line-disabled fish. Taken together, these results suggest that sedentary behavior is an important factor in promoting reliance on lateral line cues. © 2014. Published by The Company of Biologists Ltd.

  20. Proteomic identification of hair cell repair proteins in the model sea anemone Nematostella vectensis.

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    Tang, Pei-Ciao; Watson, Glen M

    2015-09-01

    Sea anemones have an extraordinary capability to repair damaged hair bundles, even after severe trauma. A group of secreted proteins, named repair proteins (RPs), found in mucus covering sea anemones significantly assists the repair of damaged hair bundle mechanoreceptors both in the sea anemone Haliplanella luciae and the blind cavefish Astyanax hubbsi. The polypeptide constituents of RPs must be identified in order to gain insight into the molecular mechanisms by which repair of hair bundles is accomplished. In this study, several polypeptides of RPs were isolated from mucus using blue native PAGE and then sequenced using LC-MS/MS. Thirty-seven known polypeptides were identified, including Hsp70s, as well as many polypeptide subunits of the 20S proteasome. Other identified polypeptides included those involved in cellular stress responses, protein folding, and protein degradation. Specific inhibitors of Hsp70s and the 20S proteasome were employed in experiments to test their involvement in hair bundle repair. The results of those experiments suggested that repair requires biologically active Hsp70s and 20S proteasomes. A model is proposed that considers the function of extracellular Hsp70s and 20S proteasomes in the repair of damaged hair cells. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Composition and diversity of ichthyofauna in La Viña reservoir (Córdoba, Argentina

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    M. Mancini

    Full Text Available Several dams have been built in central and north Argentina. There are more than 20 reservoirs in Córdoba province, with a total estimated surface area of around 15,000 ha. Although construction of dams continues, some aspects about the richness, abundance and diversity of ichthyofauna in many of these environments are unknown, which prevents adequate management of fish resources. The goal of this work was to evaluate specific richness and diversity of ichthyofauna in La Viña reservoir (31° 47' S and 65° 01' W, 1,050 ha, 846 m asl, one of the major reservoirs in Córdoba. Fifteen seasonal samplings were made in 1999-2002 using trawl nets and gillnets. A total of 3,242 specimens belonging to 7 species distributed in 5 orders and 5 families were caught. The tetra Astyanax eigenmanniorum (52.9% and the silverside Odontesthes bonariensis (29.3% were the most abundant species; the latter is the main target species for lake fishing and had greatest biomass (63.8%. Average diversity for all samples was H'T = 1.63 (95% confidence interval 1.49 to 1.77. Shannon-Wiener and Simpson diversity indexes values were generally intermediate. Specific richness of La Viña reservoir was moderate compared with other impoundments in central and north Argentina.

  2. Evolution and development in cave animals: from fish to crustaceans

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    Protas, Meredith; Jeffery, William R.

    2013-01-01

    Cave animals are excellent models to study the general principles of evolution as well as the mechanisms of adaptation to a novel environment: the perpetual darkness of caves. In this article, two of the major model systems used to study the evolution and development (evo–devo) of cave animals are described: the teleost fish Astyanax mexicanus and the isopod crustacean Asellus aquaticus. The ways in which these animals match the major attributes expected of an evo–devo cave animal model system are described. For both species, we enumerate the regressive and constructive troglomorphic traits that have evolved during their adaptation to cave life, the developmental and genetic basis of these traits, the possible evolutionary forces responsible for them, and potential new areas in which these model systems could be used for further exploration of the evolution of cave animals. Furthermore, we compare the two model cave animals to investigate the mechanisms of troglomorphic evolution. Finally, we propose a few other cave animal systems that would be suitable for development as additional models to obtain a more comprehensive understanding of the developmental and genetic mechanisms involved in troglomorphic evolution. PMID:23580903

  3. Genotoxic and mutagenic effects of polluted surface water in the midwestern region of Brazil using animal and plant bioassays

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    Priscila Leocádia Rosa Dourado

    Full Text Available Abstract This study aimed to evaluate DNA damage in animal and plant cells exposed to water from the Água Boa stream (Dourados, Mato Grosso do Sul, Brazil by using bioassays, and to identify the chemical compounds in the water to determine the water quality in the area. Through the cytotoxicity bioassay with Allium cepa, using micronucleus test, and comet assay, using Astyanax altiparanae fish, the results indicated that biological samples were genetically altered. Micronuclei were observed in erythrocytes of A. altiparanae after exposure to water from locations close to industrial waste discharge. The highest DNA damage observed with the comet assay in fish occurred with the exposure to water from locations where the presence of metals (Cu, Pb, Cd, Ni was high, indicating the possibility of genotoxic effects of these compounds. Thus, these results reinforce the importance of conducting genotoxicity tests for developing management plans to improve water quality, and indicate the need for waste management before domestic and industrial effluents are released into the rivers and streams.

  4. Assessment of the impact of chlorophyll derivatives to control parasites in aquatic ecosystems.

    Science.gov (United States)

    Erzinger, Gilmar Sidnei; Souza, Suellen Carolina; Pinto, Luciano Henrique; Hoppe, Roberto; Del Ciampo, Lineu Fernando; Souza, Ozair; Correia, Cláudia Hack Gumz; Häder, Donat-Peter

    2015-05-01

    Several research groups have studied new biopesticides which are less toxic to the environment and capable of controlling the vectors of parasitic diseases, especially in aquatic ecosystems. Pest control by photodynamic substances is an alternative to chemical or other measures, with chlorophyll and its derivatives as the most studied substances supported by their easy availability and low production costs. The impact of chlorophyll derivatives on four different species, a small crustacean (Daphnia similis), a unicellular alga (Euglena gracilis) and two species of fish (Astyanax bimaculatus and Cyprynus carpio) were tested under short-term conditions. In addition, the effects of long-term exposure were evaluated in D. similis and E. gracilis. In short-term tests, mortality of D. similis (EC50 = 7.75 mg/L) was most strongly affected by chlorophyllin, followed by E. gracilis (EC50 = 12.73 mg/L). The fish species showed a greater resistance documented by their EC50 values of 17.58 and 29.96 mg/L in C. carpio and A. bimaculatus, respectively. A risk quotient is calculated by dividing an estimate of exposure by an estimate of effect. It indicated that chlorophyll derivatives can be applied in nature to control the vectors of parasitic diseases under short-term conditions, but long-term exposure requires new formulations.

  5. Trematode Centrocestus formosanus infection and distribution in ornamental fishes in Mexico.

    Science.gov (United States)

    Ortega, César; Fajardo, Raúl; Enríquez, Ricardo

    2009-03-01

    The aim of this study was to determine the ornamental fish species affected by the metacercariae of the digenean trematode Centrocestus formosanus and its distribution in 48 fish farms in Morelos, central Mexico. The parasite was found to form various numbers of branchial cysts in 11 of the 25 species analyzed. Goldfish Carassius auratus was the most commonly affected species; 20 of 30 farms were positive for this parasite, the fish showing severe clinical signs and having a high mortality rate. For the first time in the region, koi (a variant of common carp Cyprinus carpio), zebrafish Danio rerio, suckermouth catfish Hypostomus plecostomus and blue gourami Trichogaster trichopterus (also known as the threespot gourami) were positive; meanwhile, Mexican tetra Astyanax mexicanus, which had previously been reported positive in other studies in this region, was found to be negative. The parasite was observed in fish from 27 of the 48 farms studied. Ten of 15 municipalities had farms that were positive for the parasite. These results suggest that the distribution of C. formosanus is closely related to the use of water that had been contaminated with the parasite and to the presence of a snail, the red-rimmed melania Melanoides tuberculata.

  6. Ictiofauna de sistemas cárstico-palustres con impacto antrópico: los petenes de Campeche, México

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    Ivette Liliana Torres-Castro

    2009-06-01

    Full Text Available Los petenes son pequeños manantiales y arroyos asociados que drenan a sistemas palustres en áreas cársticas costeras. Se estudió la composición, distribución y abundancia de la ictiofauna en dos petenes del noroeste de Campeche, en el manantial principal, el arroyo asociado, y pequeños ojos de agua secundarios (temporales, en dos épocas del año. Se registraron variables ambientales y tipos de impacto antrópico en cada petén. Se encontraron en total 27 especies de peces, con extensiones de ámbito de ‘Cichlasoma’ salvini, Rivulus tenuis, Phallichthys fairweatheri, Xiphophorus hellerii y X. maculatus. La especie dominante en ambas épocas fue Astyanax (probables híbridos A. aeneus × altior en Hampolol, A. altior en El Remate. Hubo diferencia significativa en diversidad entre ambos petenes. El análisis de conglomerados diferenció dos agrupaciones dentro de cada petén: aguas permanentes y sitios temporales. Las variables ambientales (excepto salinidad presentaron diferencias significativas por sitio y época; un análisis de correspondencia canónica indicó que la distribución de los conjuntos de peces tuvo influencia de las variables ambientales en ambas temporadas. En términos de composición, los factores históricos juegan un papel en las diferencias ictiológicas entre ambos petenes, sobre todo por lo que concierne a la presencia de híbridos de Astyanax, así como Xiphophorus hellerii en el petén del sur (Hampolol y de Poecilia velifera en el petén del norte (El Remate.Ichthyofauna of karstic wetlands under anthropic impact: the "petenes" of Campeche, Mexico. "Petenes" are small springs and associated streams that drain into wetlands near the coast in karstic areas. We studied composition, distribution, and abundance of the ichthyofauna in Los Petenes region (northwest Campeche. Two petenes displaying different degrees and types of anthropic impact were selected, Hampolol and El Remate. Hampolol has a smaller area but

  7. Experimental assessment of the effects of a Neotropical nocturnal piscivore on juvenile native and invasive fishes

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    Alejandra F. G. N. Santos

    Full Text Available We experimentally examined the predator-prey relationships between juvenile spotted sorubim Pseudoplastystoma corruscans and young-of-the-year invasive and native fish species of the Paraná River basin, Brazil. Three invasive (peacock bass Cichla piquiti, Nile tilapia Oreochromis niloticus, and channel catfish Ictalurus punctatus and two native (yellowtail tetra Astyanax altiparanae and streaked prochilod Prochilodus lineatus fish species were offered as prey to P. corruscans in 300 L aquaria with three habitat complexity treatments (0%, 50% and 100% structure-covered. Prey survival was variable through time and among species (C. piquiti < O. niloticus < A. altiparanae < P. lineatus < I. punctatus, depending largely on species-specific prey behavior but also on prey size and morphological defenses. Habitat complexity did not directly affect P. corruscans piscivory but some prey species changed their microhabitat use and shoaling behavior among habitat treatments in predator's presence. Pseudoplatystoma corruscans preyed preferentially on smaller individuals of those invasive species with weak morphological defensive features that persisted in a non-shoaling behavior. Overall, our results contrast with those in a companion experiment using a diurnal predator, suggesting that nocturnal piscivores preferentially prey on different (rather diurnal fish species and are less affected by habitat complexity. Our findings suggest that recovering the native populations of P. corruscans might help controling some fish species introduced to the Paraná River basin, particularly C. piquiti and O. niloticus, whose parental care is expected to be weak or null at night.

  8. Can weight/length relationship predict size at first maturity? A case study with two species of Characidae

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    Nelson F. Fontoura

    2010-01-01

    Full Text Available A weight/length relationship was established for Astyanax jacuhiensis (Cope, 1894 (n = 370 and Cheirodon ibicuhiensis Eigenmann, 1915 (n = 701, from samples taken monthly in Fortaleza Lagoon, Cidreira, Rio Grande do Sul, from December 1991 through November 1992. Both species showed a polyphasic allometric growth pattern, each stanza described by an independent power equation controlled by a switch function. For C. ibicuhiensis, this change in the growth pattern occurred at 2.948 cm standard length (SL, close to published sizes for the attainment of female maturity. The change in the growth pattern of A. jacuhiensis (SL = 3.481 cm was below the predicted size at first maturity, and merits further investigation. Although not conclusive, our data suggest that a complex growth pattern is frequent in nature, and perhaps is not usually identified because trends are obscured by natural variability. Despite the increased complexity resulting from the application of a more-complex equation, the identification of a change in the growth pattern could indicate important aspects of fish biology, including the attainment of sexual maturity.A relação peso/comprimento para Astyanax jacuhiensis (Cope, 1894 (n = 370 e Cheirodon ibicuhiensis Eigenmann, 1915 (n = 701 foi estimada a partir de amostras mensais efetuadas na lagoa Fortaleza, Cidreira, Rio Grande do Sul (dezembro de 1991 a novembro de 1992. As espécies analisadas apresentaram padrão de crescimento alométrico polifásico, sendo cada fase descrita por uma equação potência independente controlada por uma função interruptora. Para C. ibicuhiensis foi identificada uma modificação no padrão de crescimento com 2,948 cm de comprimento padrão (CP, valor próximo à dados publicados relativos ao início da maturação sexual. A alteração observada no padrão de crescimento de A. jacuhiensis (CP = 3,481 cm encontra-se abaixo do tamanho previsto para a primeira maturação e sugere a necessidade de

  9. Biologia reprodutiva e reprodução induzida de duas espécies de Characidae (Osteichthyes, Characiformes da bacia do São Francisco, Minas Gerais, Brasil Reproductive biology and induced breeding of two Characidae species (Osteichthyes, Characiformes from the São Francisco River basin, Minas Gerais, Brazil

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    Yoshimi Sato

    2006-03-01

    Full Text Available Astyanax bimaculatus (Linnaeus, 1758 e Tetragonopterus chalceus Spix & Agassiz, 1829 são duas importantes espécies de peixes forrageiros da bacia do São Francisco. Espécimes destas duas espécies foram submetidos à indução da desova através de hipofisação, para observação de aspectos reprodutivos e obtenção de subsídios para definição de protocolo de reprodução artificial. Machos e fêmeas receberam dose única de extrato bruto de hipófise de carpa comum (6 mg/kg de peixe. A extrusão de ovócitos foi realizada cerca de 12,8 e 11 h após a aplicação da injeção de hipófise, respectivamente para A. bimaculatus e T. chalceus, com a temperatura da água a 26ºC. Mais de 70% das fêmeas das duas espécies responderam positivamente ao tratamento e as taxas médias de fertilização dos ovos foram acima de 70%. Os ovócitos de A. bimaculatus e T. chalceus são esféricos, opacos, demersais, levemente adesivos, de coloração amarela ou parda, e contendo em média respectivamente 4774 e 2563 ovos por grama de ova. O desenvolvimento embrionário nas duas espécies foi rápido, com duração de menos de um dia, estando a temperatura da água entre 24 e 25ºC.Astyanax bimaculatus (Linnaeus, 1758 and Tetragonopterus chalceus Spix & Agassiz, 1829 are two important foraging species occurring at the São Francisco River basin. Specimens from both species were submitted to spawning induction through hypophysation, to study some reproductive features and to obtain subsidiary information for the definition of the artificial reproduction protocol. Males and females were treated with a single dose of crude carp pituitary extract (6 mg/kg. In water at 26ºC, the extrusion of the oocytes was made 12,8 and 11 hours after the hypophisis injection, for A. bimaculatus and T. chalceus respectively. More than 70% of the females of both species showed a positive response to the treatment and mean egg fertilization rates were above 70%. The eggs of A

  10. Development of habitat suitability criteria for Neotropical stream fishes and an assessment of their transferability to streams with different conservation status

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    Fabrício Barreto Teresa

    Full Text Available We assessed the preference of 10 fish species for depth and velocity conditions in forested streams from southeastern Brazil using habitat suitability criteria (HSC curves. We also tested whether preference patterns observed in forested streams can be transferred to deforested streams. We used data from fish sampled in 62 five-meter sites in three forested streams to construct preference curves. Astyanax altiparanae, A. fasciatus, Knodus moenkhausii, and Piabina argentea showed a preference for deep slow habitats, whereas Aspidoras fuscoguttatus, Characidium zebra, Cetopsorhamdia iheringi, Pseudopimelodus pulcher, and Hypostomus nigromaculatus showed an opposite pattern: preference for shallow fast habitats. Hypostomus ancistroides showed a multimodal pattern of preference for depth and velocity. To evaluate whether patterns observed in forested streams may be transferred to deforested streams, we sampled 64 five-meters sites in three deforested streams using the same methodology. The preference for velocity was more consistent than for depth, as success in the transferability criterion was 86% and 29% of species, respectively. This indicates that velocity is a good predictor of species abundance in streams, regardless of their conditionNeste estudo avaliamos a preferência de 10 espécies de peixes por condições de profundidade e fluxo em riachos florestados do sudeste do Brasil por meio do critério de adequabilidade de habitat (habitat suitability criteria - curvas HSC. Testamos também se os padrões de preferência observados nos riachos florestados podem ser transferidos para riachos desmatados. Foram realizadas amostragens da ictiofauna em 62 trechos de cinco metros de extensão em três riachos florestados para a construção das curvas de preferência. Astyanax altiparanae, A. fasciatus, Knodus moenkhausii e Piabina argentea apresentaram preferência por habitats lentos e profundos, enquanto Aspidoras fuscoguttatus, Characidium zebra

  11. An Index of Biotic Integrity for shallow streams of the Hondo River basin, Yucatan Peninsula

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    Schmitter-Soto, Juan J., E-mail: jschmitt@ecosur.mx; Ruiz-Cauich, Lissie E.; Herrera, Roberto L.; Gonzalez-Solis, David

    2011-01-15

    An Index of Biotic Integrity (IBI) is proposed, based on the fish communities and populations in streams of the Hondo River basin, Mexico-Belize. Freshwater environments in this area are threatened by exotic fishes, eutrophication, and pesticide pollution, among other problems. This IBI should allow to identify the most vulnerable sites and eventually guide rehabilitation efforts. Data on composition, structure, and function of fish communities were evaluated. Twenty-three sites in the Mexican part of the basin were explored; a stratified sample of 13 sites was used to design the IBI, and the rest were used to test and refine the index. Thirty-four candidate indicator metrics were scanned for their correlation with an index of water and habitat quality (IWHQ), as well as for the possible influence of stream width and altitude or distance to the Hondo River mainstem. Twelve variables were selected to constitute the IBI: relative abundances of Astyanax aeneus, 'Cichlasoma' urophthalmus, Poecilia mexicana, Poecilia sp. (a new species, probably endemic to the upper Hondo River basin), Xiphophorus hellerii, and X. maculatus; relative abundances of bentholimnetic, herbivore, and sensitive species; percentage of native and tolerant species; and Pielou's evenness index. Most of the sites have a low-medium quality and integrity, showing impact due to partial channelization or to suboptimal water quality, reflected in scarcity or absence of sensitive species, frequent excess of tolerant species, occasional presence of exotics, dominance of herbivores (perhaps due to proliferation of filamentous algae), or dominance of the opportunistic species P. mexicana. The streams with better water and habitat quality are those farthest away from the river mainstem, probably because of lower human population and economical production. - Research Highlights: {yields} An Index of Biotic Integrity based on fishes is proposed for streams of the Hondo River basin. {yields

  12. Metazoários parasitos de seis espécies de peixes do Reservatório de Lajes, Estado do Rio de Janeiro, Brasil Metazoan parasites of six fishes species from Lajes Reservoir in the State of Rio de Janeiro, Brazil

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    Aline R. Paraguassú

    2007-09-01

    Full Text Available Entre abril de 2002 e julho de 2003, foram necropsiados 231 espécimes de peixes: 39 Astyanax bimaculatus (Linnaeus, 1758, 79 A. fasciatus (Cuvier, 1819, 23 Hypostomus affinis (Steindachner, 1877, 26 Hoplias malabaricus (Bloch, 1794, 30 Loricariichthys castaneus (Castelnau, 1855 e 34 Trachelyopterus striatulus (Steindachner, 1876 provenientes do Reservatório de Lajes (22º42' - 22º50'S, 43º53' 44º05'O, Estado do Rio de Janeiro, Brasil, para estudo das suas comunidades parasitárias. A maioria dos espécimes de H. affinis (95,6% e H. malabaricus (84,6% estavam parasitados por pelo menos uma espécie de metazoário. Em A. bimaculatus, A. fasciatus, L. castaneus e T. striatulus 41%, 39,2%, 56,7% e 14,7% dos espécimes estavam parasitados, respectivamente. Foram coletadas oito diferentes espécies de metazoários parasitos: 2 em A. bimaculatus, 3 em A. fasciatus, 3 em H. affinis, 4 em H. malabaricus, 4 em L. castaneus e 1 em T. striatulus. As comunidades de metazoários parasitos das seis espécies de peixes estudadas apresentaram típico padrão de distribuição agregada. Foram observados dois casos de correlação negativa entre a abundância e a prevalência parasitárias e o comprimento total dos hospedeiros. A comunidade parasitária de L. castaneus apresentou os maiores valores de intensidade média, índice de dispersão e diversidade. As comunidades parasitárias dos peixes estudados apresentaram escassez de correlação entre a abundância, riqueza parasitária e diversidade com o comprimento total dos hospedeiros. Os baixos valores de riqueza e diversidade das comuni-dades parasitárias podem ser atribuídos as características oligotróficas do Reservatório de Lajes.From April 2002 to July 2003, 231 freshwater fishes from Lajes Reservoir in the State of Rio de Janeiro, Brazil (22º42' - 22º50'S, 43º53' - 44º05'W were necropsied to study their community metazoan parasites: 39 Astyanax bimaculatus (Linnaeus, 1758, 79 A. fasciatus

  13. Sondeo ecológico rápido de las comunidades de peces tropicales en un área de explotación minera en Costa Rica

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    Mario Espinoza Mendiola

    2008-12-01

    Full Text Available El impacto de las minerías de oro ha generado una gran preocupación por el deterioro de los hábitats acuáticos y la fragmentación de los sistemas naturales. Las perturbaciones antropogénicas sobre la estructura y heterogeneidad del sistema pueden influir en la estabilidad de las comunidades acuáticas. Sondeos ecológicos rápidos (1996, 2002, 2007 fueron empleados para determinar la estructura, composición y distribución de las comunidades de peces tropicales en varios ríos y quebradas del área de una minería de oro en el Cerro Crucitas, Costa Rica. Además, la composición de especies y abundancia relativa se relacionó con la estructura del hábitat. Se registró un total de 35 especies, de las cuales la sardina Astyanax aeneus (Characidae y la olomina Alfaro cultratus (Poeciliidae fueron las especies más abundantes (71%. La mayor riqueza de especies se observó en el Caño Crucitas (s = 19 y la quebrada Minas (s = 18. Se encontró una gran variación en la estructura y composición de las comunidades de peces, principalmente, en el río Infiernillo y Minas (λ = 0.0, F132, 66 = 2.24, p Rapid ecological assessment of tropical fish communities in a gold mine area of Costa Rica. Gold mining impacts have generated a great concern regarding aquatic systems and habitat fragmentation. Anthropogenic disturbances on the structure and heterogeneity of a system can have an important effect on aquatic community stability. Ecological rapid assessments (1996, 2002, and 2007 were employed to determine the structure, composition and distribution of tropical fish communities in several rivers and smaller creeks from a gold mining area in Cerro Crucitas, Costa Rica. In addition, species composition and relative abundance were related with habitat structure. A total of 35 species were registered, among which sardine Astyanax aeneus (Characidae and livebearer Alfaro cultratus (Poeciliidae were the most abundant fish (71%. The highest species

  14. Movement patterns of stream-dwelling fishes from Mata Atlântica, Southeast Brazil

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    Rosana Mazzoni

    2012-12-01

    Full Text Available The identification of mechanisms of spatial-temporal variation, obtained from the quantification of natural populations, is a central topic of ecological research. Despite its importance to life-history theory, as well as to conservation and management of natural populations, no studies concerning movement patterns and home range of small stream-dwelling fishes from Brazilian rain forests are known. In the present study we aimed to describe the longitudinal pattern of long distance movement as well as local patterns of short movement (daily home-range of fishes from a Mata Atlântica stream from Southeast Brazil. We gathered information about movement dynamic in order to discuss the relationship between swimming ability, fish morphology and home range. Long distance movement data were obtained in a mark-recapture experiment held in the field between June and September - 2008, on five sites along the Ubatiba stream. For this study, we had one day to mark fishes, on June-19, and 14 events for recapture. Considering the ten species that inhabit the study area, our study showed that four species: Astyanax janeiroensis, Astyanax hastatus, Parotocinclus maculicauda and Pimelodella lateristriga, moved at least 6 000m in 60 days. The other six species did not present long distance movements, as they were recaptured in the same site 90 days after being marked. For short distance study, movement data were obtained in one mark-recapture experiment held in a 100m long site subdivided into five 20m stretches where fishes were marked with different elastomer colours. We marked 583 specimens that after recapture showed two groups of different movement patterns. The first group was called “Long Movement Group” and the second one was called “Short Movement Group”. The Long Movement Group showed, on average, 89.8% of moving fishes and 10.2% of non moving fishes, against 21.3% and 78.7%, respectively, for the Short Movement Group. It was concluded that

  15. Estudio comparativo de la frecuencia de micronúcleos y anormalidades nucleares en eritrocitos de tres especies ícticas Comparative studies of the frequency of micronuclei and nuclear abnormalities in erythrocytes of three species fishes

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    Favio E Pollo

    2012-12-01

    Full Text Available Los ecosistemas acuáticos cercanos a las zonas urbanas sufren un deterioro constante ocasionado por diversos factores físico-químicos relacionados con la actividad antrópica, representando un riesgo para los organismos que los habitan, en especial los peces. Estos efectos pueden ser biomonitoreados mediante técnicas de amplia utilización, como el Test de Micronúcleos (Mn y el de Anormalidades nucleares (AN, entre otros. El objetivo de este trabajo fue verifcar y comparar la frecuencia de micronúcleos y anormalidades nucleares en tres especies ícticas colectadas en un lago urbano, Cyprinus carpio, Astyanax eigenmanniorum y Cheirodon interruptus. Luego de la captura y anestesia de los peces, se extrajo de cada individuo una muestra de sangre y se registró el peso y la longitud total. Las muestras fueron fjadas y luego teñidas con Giemsa al 10%, posteriormente se las analizó con microscopio (1000X y se les tomaron fotografías con cámara digital. Se calculó, además, el índice de condición corporal (K para cada uno de los ejemplares capturados. Se aplicó un análisis de correlación de rangos de Spearman (rs entre frecuencia de Mn y AN vs K para cada especie. La prueba de Kruskal-Wallis se aplicó para evaluar diferencias de Mn y AN entre las especies. Los resultados no mostraron una correlación estadísticamente signifcativa (P> 0,05 entre las frecuencias de Mn y AN vs K. Las frecuencias de Mn entre las diferentes especies no arrojaron diferencias signifcativas (P> 0,05, mientras que las AN sí (PAquatic ecosystems near urban areas suffer a steady deterioration caused by physical and chemical factors related to human activity, representing a danger to organisms that inhabit them, especially the fsh. These effects may be biomonitored by widely used techniques, such as the Micronucleus Test (Mn and Nuclear Abnormalities (NA, among others. The aim of this study was to verify and compare the frequency of micronuclei and nuclear

  16. Food resources used by three species of fish in the semi-arid region of Brazil

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    Márcio J. da Silva

    2010-01-01

    Full Text Available Temporary and semi-permanent aquatic habitats in semi-arid Brazil have been reported as important sites supporting a diverse fish fauna. As such, they must be able to trophically sustain fish species that feed at different trophic levels. This study aims to describe the diets of Astyanax aff. bimaculatus, Hoplias malabaricus and Prochilodus brevis in aquatic systems in semi-arid Brazil, providing evidence of the importance of these habitats as supporters of large consumers like fish. The diet of the three species studied was diverse, feeding on a range of food items, from microalgae to fish. Despite that, a few items were more important to each of the study species. These results and the relatively high rates of stomach fullness indicate that a diverse and abundant food range is available in the study sites, but species seem to select some food resources. The present study provides evidence that despite being highly variable, intermittent and semi-permanent aquatic systems in semi-arid Brazil are able to trophically sustain large consumers.Os ambientes aquáticos temporários e semi-permanentes do semiárido brasileiro tem sido mostrados como importantes sítios que possuem uma diversa fauna de peixes. Desta forma, esses ambientes devem ser capazes de sustentar, do ponto de vista trófico, populações de peixes que se alimentam em diversos níveis tróficos. O presente estudo tem como objetivo descrever o hábito alimentar de Astyanax aff. bimaculatus, Hoplias malabaricus e Prochilodus brevis em ambientes aquáticos do semiárido brasileiro, fornecendo evidências da importância desses habitats para manutenção da diversidade de consumidores como os peixes. A composição da dieta das espécies estudadas foi diversificada, já que alimentaram-se de uma variedade de classes de itens, desde microalgas até peixes. Apesar disso, alguns itens foram mais importantes para cada uma das três espécies. Estes resultados, e as altas taxas de reple

  17. Caracterização da piscicultura na região do Vale do Ribeira - SP Characterization of fish farming in the Ribeira Valley region - SP

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    Daniela Castellani

    2005-02-01

    Full Text Available Este trabalho buscou caracterizar a piscicultura na Região do Vale do Ribeira quanto aos sistemas de manejo. Estudaram-se quarenta e duas pisciculturas sendo que, destas, 36 praticam o sistema semi-intensivo e seis o sistema intensivo, com os seguintes objetivos: engorda de peixes, produção de alevinos e pesque-pagues. Foram listadas 41 espécies de peixes cultivadas. Apenas 6 espécies são nativas da Bacia do Rio Ribeira de Iguape: lambari (Astyanax sp Linneaus, 1758, traíra (Hoplias malabaricus Bloch, 1794, robalo (Centropomus ssp Cuvier e Valenciennes, 1928, jundiá (Rhamdia quelen Quoy e Gaimard, 1824, cascudo (Hypostomus sp Marschall, 1873 e cará (Geophagus brasiliensis Quoy e Gaimard, 1824. Em 95% das pisciculturas foram verificadas fugas de peixes exóticos e alóctones dos cultivos. A tilápia nilótica (Oreochromis niloticus Linneaus, 1758 foi a espécie mais freqüente em escapes, e também é a segunda mais cultivada pelos piscicultores, perdendo somente para o pacu (Piaractus mesopotamicus Halmberg, 1887. Foi possível verificar mediante o cálculo da conversão alimentar, que há um desperdício anual de cerca de 32% da ração utilizada nos cultivos pesquisados. A piscicultura encontra-se em plena expansão nesta região, e já representa a atividade agropecuária mais importante após a bananicultura.The aim of this work was to characterize the fish farming in the Ribeira de Iguape Basin, southern São Paulo State (Brazil, in relation to the management systems. Forty two farms were studied. A semi-intensive system is used by 36 farmers, while an intensive system is used only by 6 studied farmers. Their objectives were raising fish, juvenile fish production and sportive fishery. Forty one fish species were found to be cultivated, but only six were native species from Ribeira Valley: lambari (Astyanax sp Linneaus, 1758, traíra (Hoplias malabaricus Bloch, 1794, robalo (Centropomus ssp Cuvier and Valenciennes, 1928, jundi

  18. Systematic variation in the pattern of gene paralog retention between the teleost superorders Ostariophysi and Acanthopterygii.

    Science.gov (United States)

    Garcia de la Serrana, Daniel; Mareco, Edson A; Johnston, Ian A

    2014-04-01

    Teleost fish underwent whole-genome duplication around 450 Ma followed by diploidization and loss of 80-85% of the duplicated genes. To identify a deep signature of this teleost-specific whole-genome duplication (TSGD), we searched for duplicated genes that were systematically and uniquely retained in one or other of the superorders Ostariophysi and Acanthopterygii. TSGD paralogs comprised 17-21% of total gene content. Some 2.6% (510) of TSGD paralogs were present as pairs in the Ostariophysi genomes of Danio rerio (Cypriniformes) and Astyanax mexicanus (Characiformes) but not in species from four orders of Acanthopterygii (Gasterosteiformes, Gasterosteus aculeatus; Tetraodontiformes, Tetraodon nigroviridis; Perciformes, Oreochromis niloticus; and Beloniformes, Oryzias latipes) where a single copy was identified. Similarly, 1.3% (418) of total gene number represented cases where TSGD paralogs pairs were systematically retained in the Acanthopterygian but conserved as a single copy in Ostariophysi genomes. We confirmed the generality of these results by phylogenetic and synteny analysis of 40 randomly selected linage-specific paralogs (LSPs) from each superorder and completed with the transcriptomes of three additional Ostariophysi species (Ictalurus punctatus [Siluriformes], Sinocyclocheilus species [Cypriniformes], and Piaractus mesopotamicus [Characiformes]). No chromosome bias was detected in TSGD paralog retention. Gene ontology (GO) analysis revealed significant enrichment of GO terms relative to the human GO SLIM database for "growth," "Cell differentiation," and "Embryo development" in Ostariophysi and for "Transport," "Signal Transduction," and "Vesicle mediated transport" in Acanthopterygii. The observed patterns of paralog retention are consistent with different diploidization outcomes having contributed to the evolution/diversification of each superorder.

  19. Ictiofauna de los humedales del río San Pedro, Balancán, Tabasco, México

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    Alfonso Castillo-Domínguez

    2011-06-01

    Full Text Available Los humedales de San Pedro sostienen redes tróficas del sistema fluvial debido a la alta disponibilidad de hábitats y a sus variaciones espacio-temporales. En esta investigación se estudió la composición, densidad y biomasa de la ictiofauna de los humedales; se capturaron 1 049 organismos de 25 especies, dos son exóticas: Oreochromis niloticus y Parachromis managuense. Con 23 especies capturadas en el sitio I, 17 en el II y 14 en el III. En la época de secas se obtuvo mayor riqueza con 21 especies, lluvias con 17 y cinco en nortes. La mayor densidad se mostró en el sitio II (0.23ind./m², seguido de los sitios I y III (0.12, 0.12ind./m². La mayor biomasa fue en secas (8.30g/m², seguida de lluvias (2.1g/m² y por último nortes (0.01g/m². La mayor densidad se mostró en secas (0.43ind./m² y la mínima en nortes (0.023ind./m². Las especies dominantes en densidad según el diagrama Olmstead-Tukey fueron: Petenia splendida, Vieja heterospila, Vieja synspila, Dorosoma petenense y Astyanax aeneus. Por lo tanto, existieron diferencias significativas en los parámetros ecológicos y ambientales. Al considerar la variación en la riqueza podemos concluir que los humedales del río San Pedro, es un sistema donde la composición de la ictiofauna responde a las fluctuaciones espaciales y temporales.

  20. Caracterización de la estructura de peces ornamentales durante dos períodos hidrológicos en el caño agua limón, departamento de Arauca, Colombia

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    Ruiz Moreno Andrés Ricardo

    2006-06-01

    Full Text Available Se realizó un inventarió de los peces ornamentales en el caño Agua Limón, en el municipio de Arauca, Arauca (Colombia, en los períodos comprendidos de febrero a mayo de 2005 y de septiembre a agosto de 2005. Como estrategia metodológica para el estudio se realizó un esfuerzo de captura de dos horas por jornada empleando como artes de pesca el trasmallo de fibra de nylon y el aro. Se registraron 4.753 individuos que
    corresponden a 74 especies pertenecientes a 21 familias donde las especies más abundantes fueron Ctenobrycon spilurus (22%, Astyanax sp. (18% y Gephyrocharax sp. (10%. Los órdenes con mayor representación específica fueron Characiformes y Siluruformes (reuniendo el 71% de las capturas. Las familias con mayor riqueza de especies fueron Characidae (24 spp. y Loricariidae (12 spp. seguidas por las familias Cichlidae (6 spp., Apteronotidae y Pimelodidae con cuatro especies, Auchenipteridae y Callichthydae con tres especies cada una. La mayor riqueza de especies se encontró en los meses de septiembre, agosto y marzo, se sugiere que estos resultados están relacionados con las variaciones del régimen hidrológico de esta región dando como consecuencia cambios de distribución en los cuerpos de agua que frecuentan las especies. El mes de mayo tiene la menor diversidad y al
    mayor abundancia de especies.

  1. Cobalt Chloride Treatment Used to Ablate the Lateral Line System Also Impairs the Olfactory System in Three Freshwater Fishes.

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    Julie M Butler

    Full Text Available Fishes use multimodal signals during both inter- and intra-sexual displays to convey information about their sex, reproductive state, and social status. These complex behavioral displays can include visual, auditory, olfactory, tactile, and hydrodynamic signals, and the relative role of each sensory channel in these complex multi-sensory interactions is a common focus of neuroethology. The mechanosensory lateral line system of fishes detects near-body water movements and is implicated in a variety of behaviors including schooling, rheotaxis, social communication, and prey detection. Cobalt chloride is commonly used to chemically ablate lateral line neuromasts, thereby eliminating water-movement cues to test for mechanosensory-mediated behavioral functions. However, cobalt acts as a nonspecific calcium channel antagonist and could potentially disrupt function of all superficially located sensory receptor cells, including those for chemosensing. Here, we examined whether CoCl2 treatment used to ablate the lateral line system also impairs olfaction in three freshwater fishes, the African cichlid fish Astatotilapia burtoni, goldfish Carassius auratus, and the Mexican blind cavefish Astyanax mexicanus. To examine the impact of CoCl2 on the activity of peripheral receptors, we quantified DASPEI fluorescence intensity of the olfactory epithelium from fish exposed to control and CoCl2 solutions. In addition, we examined brain activation in olfactory processing regions of A. burtoni immersed in either control or cobalt solutions. All three species exposed to CoCl2 had decreased DASPEI staining of the olfactory epithelium, and in A. burtoni, cobalt treatment caused reduced neural activation in olfactory processing regions of the brain. To our knowledge this is the first empirical evidence demonstrating that the same CoCl2 treatment used to ablate the lateral line system also impairs olfactory function. These data have important implications for the use of

  2. Mutagenic effects of tributyltin and inorganic lead (Pb II on the fish H. malabaricus as evaluated using the comet assay and the piscine micronucleus and chromosome aberration tests

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    Marcos Vinícius M. Ferraro

    2004-01-01

    Full Text Available Genotoxicity studies on toxic metals and their organic compounds are very important, especially so in the investigation of the effects of these compounds on the aquatic environments where they tend to accumulate. The use of endemic aquatic organisms as biological sentinels has proved useful to environmental monitoring. We assessed the mutagenic potential of tributyltin (TBT and inorganic lead (PbII using samples of the fish Hoplias malabaricus (commonly called traíra using the comet assay and the piscine micronucleus and chromosome aberration tests. Eighteen H. malabaricus were acclimatized in three individual aquariums, each containing six fish, six fish being exposed to 0.3 mg/g of body weight (bw of TBT, six to 21 mg/g bw of PbII and six being used as controls. Exposure to TBT and PbII was achieved by feeding the fish every five days with Astyanax (a small fish that is part of the normal diet of H. malabaricus which had been injected with solutions of TBT, PbII or with water (the control group. After two months the H. malabaricus were sacrificed and their peripheral blood collected and subjected to the comet and micronucleus assays, the chromosome aberration assay being conducted using kidney-tissue. Although the comet assay showed now mutagenic effects at the lead concentrations used but encountered results with TBT, the micronucleus and chromosome aberrations assays both indicated that TBT and PbII are potentially mutagenic (p < 0.01, the micronucleus assay showing morphological alterations of the nucleus.

  3. Mesohabitat indicator species in a coastal stream of the Atlantic rainforest, Rio de Janeiro-Brazil

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    Carla Ferreira Rezende

    2010-12-01

    Full Text Available The Mato Grosso is a typical Atlantic Forest stream located on the East coast of Brazil, approximately 70km from Rio de Janeiro city. From its source at about 800m a.s.l, the stream drains a 30km² area of the Northwestern part of the municipality of Saquarema, state of Rio de Janeiro and flows into the Saquarema Lagoon system. We hypothesized that fish species occupy distinct mesohabitats, with the prediction that their occurrences and densities differ among the microhabitats of riffles, runs and pools. A 250m-long stretch of the stream located in its uppermost part was selected for this study, where it becomes second-order. Mesohabitat description and their fish characterization were undertaken. Fish sampling was conducted by electroshocking and after their identification and counting, they were returned to the stream. For mesohabitat characterization, a Discriminant Function Analysis (DA was applied. The total number of samples was estimated by the Zippin method and the recorded densities were used as an Indicator Species Analysis (ISA, followed by a Monte Carlo test for 1 000 permutations. The DA significantly separated the three predetermined mesohabitats (pool, riffle and run (WL=0.13, F=187.70, p=0.001. We found five species of fishes, belonging to four families and three orders. The fishes Rhamdia quelen, Phalloceros harpagos, Pimelodella lateristriga and Astyanax taeniatus are indicators of the pool environment in the Mato Grosso stream, whereas Characidium cf. vidali is an indicator of the riffle environment. The Monte Carlo test detected non-random mesohabitat use only for P. lateristriga and A. taeniatus in the pools and for Characidium cf. vidali in the riffles. We concluded that the Mato Grosso stream contains three well-defined mesohabitats, with indicator species present in two of these mesohabitats. Rev. Biol. Trop. 58 (4: 1479-1487. Epub 2010 December 01.

  4. Lake size and fish diversity in southern Brazil coastal lagoons

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    Lucia Ribeiro Rodrigues

    2015-10-01

    Full Text Available The coastal plain of Rio Grande do Sul, southern Brazil, presents a series of shallow lagoons with diverse size and morphology. The objective of this study is to determine whether the size of the lagoon is an effective factor for structuring fish diversity. In this regard, nine lagoons with distinct areas were sampled: three with an area up to 40 hectares, three with area between 40 and 80 hectares, and three with an area of over 80 hectares. Each lagoon was sampled once on the littoral and pelagic zones. At each point, fish were captured through a set of gill nets with different mesh sizes. Captured specimens were identified, quantified and evaluated for weight and length. A total of 24 fish species belonging to 10 families was obtained, with Characidae presenting the highest species richness. Cyanocharax alburnus was the only species that occurred in all lagoons. Cyphocharax voga, Astyanax eigenmmaniorum, Oligosarcus jenynsii and O. robustus were also frequent species, present in most of the sampled lagoons. Lycengraulis grossidens was captured in just two lagoons with increased conductivity. The community structure showed the highest species richness in lakes with an area over 40 ha, however the highest mean diversity values were observed in ponds up to 40 ha. Cluster Analysis yielded the formation of two groups: a group formed by just one lagoon and a second one cluster grouping all the other lagoons. This pattern may be associated with the presence of Lycengraulis grossidens as a dominant species in this lagoon clustered apart. The results indicate that lagoons with up to 40 ha present greater homogeneity on the species composition and higher average values of diversity; while intermediate ponds (between 40 and 80 ha have lower average diversity for the fish fauna due to increased heterogeneity in species abundance.

  5. The fish fauna in the fish passage at the Ourinhos Dam, Paranapanema River

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    Marlene Sofia Arcifa

    Full Text Available The composition and abundance of the fish assemblage were evaluated in the fish ladder of Ourinhos Dam, the newest dam (closed in 2005 in the cascade of dams constructed on the Paranapanema River. Samplings were carried out three times on a diel cycle, in three sampling periods, two in the warm season and one in the cold season of 2008 - 2009. The ladder was closed and emptied and the entire fish assemblage was sampled and identified. Most individuals were released alive downstream of the dam. The assemblage found in the ladder was compared with the fish fauna sampled in the reservoir and in downstream sites, in the same period. Twenty seven species and a total of 4682 individuals were caught in the ladder. Pimelodus maculatus was the only migratory species, which was caught in low number in the ladder (0.04% of the total captured, where small sedentary species predominated. The most abundant species were the non-migratory Apareiodon affinis, Bryconamericus stramineus, Astyanax fasciatus and Parodon nasus. Individuals observed in the ladder's window were moving up- and down the passage. The fish ladder is a microhabitat inhabited by an abundant association of benthic organisms that is probably used as a food resource for the fish assemblage in the ladder. The similarity between the fish fauna in the ladder and that of the Ourinhos Reservoir was low (26%. The species richness of migrants in the stretch between the uspstream reservoir (Chavantes and the downstream one (Salto Grande, before the Ourinhos dam closure (23 species was reduced to 16 and 12 species in Salto Grande and Ourinhos reservoirs, respectively, after the dam closure, and to a single species in the ladder.

  6. Biochemical responses in freshwater fish after exposure to water-soluble fraction of gasoline.

    Science.gov (United States)

    Bettim, Franciele Lima; Galvan, Gabrieli Limberger; Cestari, Marta Margarete; Yamamoto, Carlos Itsuo; de Assis, Helena Cristina Silva

    2016-02-01

    The water-soluble fraction of gasoline (WSFG) is a complex mixture of mono-polycyclic aromatic hydrocarbons. The study aimed to evaluate the effects of WSFG diluted 1.5% on freshwater fish. Astyanax altiparanae were exposed to the WSFG for 96 h, under a semi-static system, with renewal of 25% of the gasoline test solution every 24 h. In addition, a decay of the contamination (DC) was carried out. During DC, the fish was exposed to the WSFG for 8 d, followed by another 7 d with renewal of 25% of volume aquaria with clean water every 24 h. For depuration, fish were transferred to aquaria with clean water, and in addition, 25% of the water was replaced every 24 h. The liver and kidney biotransformation, antioxidant defenses and lipid peroxidation (LPO) levels were evaluated. In the liver, the WSFG 1.5% caused reduction of glutathione S-transferase (GST) after 96 h and DC. In the kidney, only in depuration an increased GST activity was observed, and after DC a higher LPO levels. An increase of the superoxide dismutase (SOD) activity occurred at 96 h in both tissues; however, in the liver was also observed during the depuration. In WSFG 96 h, the glutathione peroxidase (GPx) activity in the kidney increased. As biomarkers of neurotoxicity, the brain and muscle acetylcholinesterase activities were measured, but the WSFG 1.5% did not change them. Therefore, this study brought forth more data about WSFG effects on freshwater fish after lower concentrations exposure and a DC, simulating an environmental contamination. Copyright © 2015. Published by Elsevier Ltd.

  7. A Genomic Survey of SCPP Family Genes in Fishes Provides Novel Insights into the Evolution of Fish Scales

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    Yunyun Lv

    2017-11-01

    Full Text Available The family of secretory calcium-binding phosphoproteins (SCPPs have been considered vital to skeletal tissue mineralization. However, most previous SCPP studies focused on phylogenetically distant animals but not on those closely related species. Here we provide novel insights into the coevolution of SCPP genes and fish scales in 10 species from Otophysi. According to their scale phenotypes, these fishes can be divided into three groups, i.e., scaled, sparsely scaled, and scaleless. We identified homologous SCPP genes in the genomes of these species and revealed an absence of some SCPP members in some genomes, suggesting an uneven evolutionary history of SCPP genes in fishes. In addition, most of these SCPP genes, with the exception of SPP1, individually form one or two gene cluster(s on each corresponding genome. Furthermore, we constructed phylogenetic trees using maximum likelihood method to estimate their evolution. The phylogenetic topology mostly supports two subclasses in some species, such as Cyprinus carpio, Sinocyclocheilus anshuiensis, S. grahamin, and S. rhinocerous, but not in the other examined fishes. By comparing the gene structures of recently reported candidate genes, SCPP1 and SCPP5, for determining scale phenotypes, we found that the hypothesis is suitable for Astyanax mexicanus, but denied by S. anshuiensis, even though they are both sparsely scaled for cave adaptation. Thus, we conclude that, although different fish species display similar scale phenotypes, the underlying genetic changes however might be diverse. In summary, this paper accelerates the recognition of the SCPP family in teleosts for potential scale evolution.

  8. Cobalt Chloride Treatment Used to Ablate the Lateral Line System Also Impairs the Olfactory System in Three Freshwater Fishes.

    Science.gov (United States)

    Butler, Julie M; Field, Karen E; Maruska, Karen P

    2016-01-01

    Fishes use multimodal signals during both inter- and intra-sexual displays to convey information about their sex, reproductive state, and social status. These complex behavioral displays can include visual, auditory, olfactory, tactile, and hydrodynamic signals, and the relative role of each sensory channel in these complex multi-sensory interactions is a common focus of neuroethology. The mechanosensory lateral line system of fishes detects near-body water movements and is implicated in a variety of behaviors including schooling, rheotaxis, social communication, and prey detection. Cobalt chloride is commonly used to chemically ablate lateral line neuromasts, thereby eliminating water-movement cues to test for mechanosensory-mediated behavioral functions. However, cobalt acts as a nonspecific calcium channel antagonist and could potentially disrupt function of all superficially located sensory receptor cells, including those for chemosensing. Here, we examined whether CoCl2 treatment used to ablate the lateral line system also impairs olfaction in three freshwater fishes, the African cichlid fish Astatotilapia burtoni, goldfish Carassius auratus, and the Mexican blind cavefish Astyanax mexicanus. To examine the impact of CoCl2 on the activity of peripheral receptors, we quantified DASPEI fluorescence intensity of the olfactory epithelium from fish exposed to control and CoCl2 solutions. In addition, we examined brain activation in olfactory processing regions of A. burtoni immersed in either control or cobalt solutions. All three species exposed to CoCl2 had decreased DASPEI staining of the olfactory epithelium, and in A. burtoni, cobalt treatment caused reduced neural activation in olfactory processing regions of the brain. To our knowledge this is the first empirical evidence demonstrating that the same CoCl2 treatment used to ablate the lateral line system also impairs olfactory function. These data have important implications for the use of CoCl2 in future

  9. Utilization of the fish ladder at the Engenheiro Sergio Motta Dam, Brazil, by long distance migrating potamodromous species

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    Sérgio Makrakis

    Full Text Available Utilization of the fish ladder installed at the Engenheiro Sergio Motta Dam (also known as Porto Primavera on the Paraná River, Southern Brazil, by long-distance migrating potamodromous species (sampling Protocol I, and ascending and descending movements (Protocol II were evaluated. Three pools along the fish ladder (designated as lower, middle, and upper were sampled monthly between December, 2004 and March, 2005 to determine the abundance of species in the ladder. The ascending and descending movements of the species in the ladder were also analyzed in the same period. In the samples for both protocols, 37 species representing 17 families and 5 orders (Characiformes, Siluriformes, Perciformes, Gymnotiformes, and Myliobatiformes were recorded. Characiformes were represented by 21 species. Long- distance migratory species (11 species predominated in the ladder (60% of the total number of individuals, with high abundance of Rhinelepis aspera (5645 individuals. For protocol I, mean abundance varied greatly among the months and pools, with lowest values in December and March for all pools, and highest in January for the lower pool due to high capture of R. aspera. Fish abundance declined from the lower to the upper pool, especially for R. aspera and Rhaphiodon vulpinus. For Protocol II, 17 species were recorded ascending the ladder, where Astyanax altiparanae and Leporinus friderici were the most abundant species (684 and 111 individuals, respectively. However, 18 species showed descending movements, with high captures of Metynnis maculatus and A. altiparanae (339 and 319 individuals, respectively. Twelve species (52% moved in both directions, and among the seven migratory species sampled, four were recorded ascending and descending, and three species only ascending the ladder. The fish ladder appears to selectively favor species with high swimming capabilities. A discussion is presented on the requirements for future research on attraction to the

  10. Longitudinal habitat disruption in Neotropical streams: fish assemblages under the influence of culverts

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    José Roberto Mariano

    Full Text Available This study assessed differences in fish assemblages existing upstream and downstream two types of culverts, one on each of two different Neotropical streams. We analyzed the composition and structure of the ichthyofauna and tested for spatial patterns. Fish sampling was carried out monthly between November 2009 and October 2010 using different fishing gears. We collected 2,220 fish of 33 species; 901 in stretches of the Lopeí stream - circular culvert and 1,310 in stretches of the Pindorama stream - box culvert. Fish abundance was similar in upstream and downstream stretches of the circular culvert, whereas it was slightly higher in the upstream than downstream stretch for the box culvert. Characiformes predominated in the upstream stretch of both culverts. On the other hand, Siluriformes was abundant in the downstream stretch of the circular culvert, with similar abundance in the stretches of the box culvert. Species richness and diversity (Shannon-Weiner Index were higher in the downstream stretch of the circular culvert, but they were similar in both stretches of the box culvert. The most abundant species were Astyanax altiparanae, A. paranae, A. fasciatus, Ancistrus sp., and Hypostomus sp. The last two species were more abundant in the downstream stretch of the circular culvert, and similar in stretches of the box culvert. Our study indicated variations in the species abundance, richness, and diversity between upstream and downstream stretches in particular of the circular culvert in the Lopeí stream, suggesting that fish movements are restrained more intensively in this culvert, especially for Siluriformes. The drop in the circular culvert outlet probably created passage barriers especially for those fish that has no ability to jump, where downstream erosion could lead to culvert perching. Studies on appropriate road crossing design or installation are fundamental whereas improvements in these structures can restore the connectivity of

  11. An Index of Biotic Integrity for shallow streams of the Hondo River basin, Yucatan Peninsula.

    Science.gov (United States)

    Schmitter-Soto, Juan J; Ruiz-Cauich, Lissie E; Herrera, Roberto L; González-Solís, David

    2011-01-15

    An Index of Biotic Integrity (IBI) is proposed, based on the fish communities and populations in streams of the Hondo River basin, Mexico-Belize. Freshwater environments in this area are threatened by exotic fishes, eutrophication, and pesticide pollution, among other problems. This IBI should allow to identify the most vulnerable sites and eventually guide rehabilitation efforts. Data on composition, structure, and function of fish communities were evaluated. Twenty-three sites in the Mexican part of the basin were explored; a stratified sample of 13 sites was used to design the IBI, and the rest were used to test and refine the index. Thirty-four candidate indicator metrics were scanned for their correlation with an index of water and habitat quality (IWHQ), as well as for the possible influence of stream width and altitude or distance to the Hondo River mainstem. Twelve variables were selected to constitute the IBI: relative abundances of Astyanax aeneus, 'Cichlasoma' urophthalmus, Poecilia mexicana, Poecilia sp. (a new species, probably endemic to the upper Hondo River basin), Xiphophorus hellerii, and X. maculatus; relative abundances of bentholimnetic, herbivore, and sensitive species; percentage of native and tolerant species; and Pielou's evenness index. Most of the sites have a low-medium quality and integrity, showing impact due to partial channelization or to suboptimal water quality, reflected in scarcity or absence of sensitive species, frequent excess of tolerant species, occasional presence of exotics, dominance of herbivores (perhaps due to proliferation of filamentous algae), or dominance of the opportunistic species P. mexicana. The streams with better water and habitat quality are those farthest away from the river mainstem, probably because of lower human population and economical production. Copyright © 2010 Elsevier B.V. All rights reserved.

  12. Trophic structure of a fish community in Bananal stream subbasin in Brasília National Park, Cerrado biome (Brazilian Savanna, DF

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    Mariana Schneider

    Full Text Available The aim of this study was to determine the trophic structure of the fish community in the Bananal stream subbasin, which belongs to a well-preserved Cerrado area (Brazilian Savanna in Brasília National Park, Brazil. We also evaluated the influence of environmental variations in the diet of fish species. Four samples were taken in each 30 m long established transect, two in the rainy season and two in the dry season. A total of 1,050 stomachs of the 13 most abundant species were analyzed. A total of 36 food items were consumed, where 24 were autochthonous, 8 allochthonous, and 4 of undetermined origin. Non-metric multidimensional scaling (NMDS analysis, in addition to the results of frequency of occurrence and abundance charts, was used to determine four groups of feeding guilds: detritivores, omnivores (tending toward herbivory and invertivory, invertivores and piscivores. Around 69% of the volume of resources consumed was allochthonous, which proves the importance of the resources provided by riparian vegetation. The contribution of autochthonous and allochthonous items in the diet differed due to seasonality for Aspidoras fuscoguttatus, Astyanax sp., Characidium xanthopterum, Hyphessobrycon balbus, Kolpotocheirodon theloura, Moenkhausia sp., Phalloceros harpagos, and Rivulus pictus. Despite the Cerrado climate characteristics, there was no significant influence of season on the fish diet. The absence of seasonal variation and the predominance of allochthonous items in the fish diet are probably associated with the presence of riparian vegetation, which acts as a transition area in the Cerrado biome and provides resources for the aquatic fauna. This work shows the importance of studies in non-disturbed areas considered here as a source of information concerning the biology of fish species and as a guide for direct conservation policies on the management of aquatic resources, recovery of damaged areas and determination of priority areas for

  13. Distinct genetic architecture underlies the emergence of sleep loss and prey-seeking behavior in the Mexican cavefish.

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    Yoshizawa, Masato; Robinson, Beatriz G; Duboué, Erik R; Masek, Pavel; Jaggard, James B; O'Quin, Kelly E; Borowsky, Richard L; Jeffery, William R; Keene, Alex C

    2015-02-20

    Sleep is characterized by extended periods of quiescence and reduced responsiveness to sensory stimuli. Animals ranging from insects to mammals adapt to environments with limited food by suppressing sleep and enhancing their response to food cues, yet little is known about the genetic and evolutionary relationship between these processes. The blind Mexican cavefish, Astyanax mexicanus is a powerful model for elucidating the genetic mechanisms underlying behavioral evolution. A. mexicanus comprises an extant ancestral-type surface dwelling morph and at least five independently evolved cave populations. Evolutionary convergence on sleep loss and vibration attraction behavior, which is involved in prey seeking, have been documented in cavefish raising the possibility that enhanced sensory responsiveness underlies changes in sleep. We established a system to study sleep and vibration attraction behavior in adult A. mexicanus and used high coverage quantitative trait loci (QTL) mapping to investigate the functional and evolutionary relationship between these traits. Analysis of surface-cave F2 hybrid fish and an outbred cave population indicates that independent genetic factors underlie changes in sleep/locomotor activity and vibration attraction behavior. High-coverage QTL mapping with genotyping-by-sequencing technology identify two novel QTL intervals that associate with locomotor activity and include the narcolepsy-associated tp53 regulating kinase. These QTLs represent the first genomic localization of locomotor activity in cavefish and are distinct from two QTLs previously identified as associating with vibration attraction behavior. Taken together, these results localize genomic regions underlying sleep/locomotor and sensory changes in cavefish populations and provide evidence that sleep loss evolved independently from enhanced sensory responsiveness.

  14. ESTADO DEL CONOCIMIENTO DE LAS CONCENTRACIONES DE MERCURIO Y OTROS METALES PESADOS EN PECES DULCEACUÍCOLAS DE COLOMBIA

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    NÉSTOR JAVIER MANCERA-RODRÍGUEZ

    2006-01-01

    Full Text Available Una de las problemáticas ambientales más importantes en el país se refiere al uso indiscriminado de precursores químicos en actividades ilícitas, el uso de metales pesados como mercurio en actividades mineras, el vertimiento de aguas servidas y otro tipo de compuestos relacionados con actividades industriales y prácticas agrícolas inadecuadas. Lo anterior, ha llevado a que la contaminación química en especial por metales pesados, constituya una de las más peligrosas para los ecosistemas acuáticos y las especies presentes en ellos. Los peces tienen la capacidad de almacenar en su organismo una concentración mayor de estos compuestos en comparación con la presente en el medio, por lo que son un indicador importante de la contaminación, pero también esto implica que su consumo se puede convertir en un problema de salud para las poblaciones que se alimentan de este recurso. La concentración de meta- les pesados en peces de agua dulce es conocida de mejor manera en la cuenca del río Magdalena, especialmente en la región de la Mojana y en las ciénagas del sur del departamento de Bolívar donde se han estudiado los niveles de contaminación por mercurio y otros metales producida por el desarrollo de múltiples actividades indus- triales, entre las cuales sobresalen la minería de oro y la petroquímica. Sin embargo, es escaso el conocimiento que se tiene en el país de la problemática generada por la disposición en los cuerpos de agua de metales pesados y su impacto sobre el recurso íctico, el deterioro de ecosistemas y la salud humana. Con base en las normas vigentes se han realizado bioensayos como criterio para comprobar los efectos de la contami- nación acuática con organismos dulceacuícolas y la evaluación de por lo menos tres parámetros (metales pesados, temperatura, efluentes, utilizando ocho especies de pe- ces dulceacuícolas: Carassius auratus, Oreochromis spp., Piractus brachypomus, Prochilodus magdalenae, Astyanax

  15. Evidence for Adaptation to the Tibetan Plateau Inferred from Tibetan Loach Transcriptomes

    Science.gov (United States)

    Wang, Ying; Yang, Liandong; Zhou, Kun; Zhang, Yanping; Song, Zhaobin; He, Shunping

    2015-01-01

    Abstract Triplophysa fishes are the primary component of the fish fauna on the Tibetan Plateau and are well adapted to the high-altitude environment. Despite the importance of Triplophysa fishes on the plateau, the genetic mechanisms of the adaptations of these fishes to this high-altitude environment remain poorly understood. In this study, we generated the transcriptome sequences for three Triplophysa fishes, that is, Triplophysa siluroides, Triplophysa scleroptera, and Triplophysa dalaica, and used these and the previously available transcriptome and genome sequences from fishes living at low altitudes to identify potential genetic mechanisms for the high-altitude adaptations in Triplophysa fishes. An analysis of 2,269 orthologous genes among cave fish (Astyanax mexicanus), zebrafish (Danio rerio), large-scale loach (Paramisgurnus dabryanus), and Triplophysa fishes revealed that each of the terminal branches of the Triplophysa fishes had a significantly higher ratio of nonsynonymous to synonymous substitutions than that of the branches of the fishes from low altitudes, which provided consistent evidence for genome-wide rapid evolution in the Triplophysa genus. Many of the GO (Gene Ontology) categories associated with energy metabolism and hypoxia response exhibited accelerated evolution in the Triplophysa fishes compared with the large-scale loach. The genes that exhibited signs of positive selection and rapid evolution in the Triplophysa fishes were also significantly enriched in energy metabolism and hypoxia response categories. Our analysis identified widespread Triplophysa-specific nonsynonymous mutations in the fast evolving genes and positively selected genes. Moreover, we detected significant evidence of positive selection in the HIF (hypoxia-inducible factor)-1A and HIF-2B genes in Triplophysa fishes and found that the Triplophysa-specific nonsynonymous mutations in the HIF-1A and HIF-2B genes were associated with functional changes. Overall, our study

  16. Uso de biomarcadores para monitoramento das águas do Córrego Arara no município de Rio Brilhante, MS, Brasil

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    Elisangela Bortoluci Maceda

    2015-01-01

    Full Text Available O objetivo deste trabalho foi avaliar a mutagenicidade, genotoxicidade e citotoxicidade de amostras de água provenientes do Córrego Arara no município de Rio Brilhante, MS, Brasil, por meio de testes toxicológicos utilizando biomarcadores. Para avaliar a mutagenicidade utilizou-se o teste de micronúcleo, para a genotoxicidade o ensaio cometa, ambos com Astyanax altiparanae, e para analisar a citotoxicidade utilizou-se o teste de Allium cepa. As coletas foram realizadas nos meses de abril e junho de 2013, em três pontos distintos (pontos 1, 2 e 3 do Córrego Arara e no Tanque de Irrigação da UFGD (ponto 4. Os resultados indicaram aumento significativo na frequência de micronúcleos pisceos na coleta do mês de junho quando comparada com a realizada em abril. No teste de Allium cepa, o efeito citotóxico apresentou-se significativamente maior na coleta de abril, porém a genotoxicidade das águas não apresentou diferença estatística entre os meses de coleta. O maior número de danos no ensaio cometa ocorreu no ponto 4, em ambos períodos de coleta. A análise química da água indicou níveis de cádmio, cromo, cobre, chumbo e níquel, com valores superiores ao permitido pela legislação vigente. A presença de metais acima dos níveis permitidos nas amostras de água analisadas do Córrego Arara indica possíveis potenciais mutagênicos, genotóxicos e citotóxicos aos organismos devido a esses poluentes derivados ou não de ações antrópicas. Assim sendo, este trabalho pode contribuir como ferramenta adicional ao controle da qualidade da água do Córrego Arara, considerando sua utilização e importância para a região.

  17. [Rapid ecological assessment of tropical fish communities in a gold mine area of Costa Rica].

    Science.gov (United States)

    Espinoza Mendiola, Mario

    2008-12-01

    Gold mining impacts have generated a great concern regarding aquatic systems and habitat fragmentation. Anthropogenic disturbances on the structure and heterogeneity of a system can have an important effect on aquatic community stability. Ecological rapid assessments (1996, 2002, and 2007) were employed to determine the structure, composition and distribution of tropical fish communities in several rivers and smaller creeks from a gold mining area in Cerro Crucitas, Costa Rica. In addition, species composition and relative abundance were related with habitat structure. A total of 35 species were registered, among which sardine Astyanax aeneus (Characidae) and livebearer Alfaro cultratus (Poeciliidae) were the most abundant fish (71%). The highest species richness was observed in Caño Crucitas (s=19) and Minas Creek (s=18). Significant differences in fish communities structure and composition from Infiernillo river and Minas creek were observed (lamda = 0.0, F(132, 66) = 2.24, p < 0.001). Presence and/or absence of certain species such as Dormitor gobiomorus, Rhamdia nicaraguensis, Parachromis loiseillei and Atractosteus tropicus explained most of the spatial variation among sites. Habitat structure also contributed to explain differences among sites (lamda = 0.004, F(60.183) = 5.52, p < 0.001). Substratum (soft and hard bottom types) and habitat attributes (elevation, width and depth) explained most of the variability observed in Infiernillo River, Caño Crucitas and Tamagá Creek. In addition, a significant association between fish species and habitat structure was observed. This study reveals a high complexity in tropical fish communities that inhabit a gold mine area. Furthermore, it highlights the importance of habitat heterogeneity in fish community dynamics. The loss and degradation of aquatic systems in Cerro Crucitas can have a strong negative effect on fish community structure and composition of local species. A better understanding of the use of specific

  18. ESTADO DEL CONOCIMIENTO DE LAS CONCENTRACIONES DE MERCURIO Y OTROS METALES PESADOS EN PECES DULCEACUÍCOLAS DE COLOMBIA Current State of Knowledge of the Concentration of Mercury and Other Heavy Metals in Fresh Water Fish in Colombia

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    NÉSTOR JAVIER MANCERA-RODRÍGUEZ

    2006-06-01

    Full Text Available Una de las problemáticas ambientales más importantes en el país se refiere al uso indiscriminado de precursores químicos en actividades ilícitas, el uso de metales pesados como mercurio en actividades mineras, el vertimiento de aguas servidas y otro tipo de compuestos relacionados con actividades industriales y prácticas agrícolas inadecuadas. Lo anterior, ha llevado a que la contaminación química en especial por metales pesados, constituya una de las más peligrosas para los ecosistemas acuáticos y las especies presentes en ellos. Los peces tienen la capacidad de almacenar en su organismo una concentración mayor de estos compuestos en comparación con la presente en el medio, por lo que son un indicador importante de la contaminación, pero también esto implica que su consumo se puede convertir en un problema de salud para las poblaciones que se alimentan de este recurso. La concentración de metales pesados en peces de agua dulce es conocida de mejor manera en la cuenca del río Magdalena, especialmente en la región de la Mojana y en las ciénagas del sur del departamento de Bolívar donde se han estudiado los niveles de contaminación por mercurio y otros metales producida por el desarrollo de múltiples actividades industriales, entre las cuales sobresalen la minería de oro y la petroquímica. Sin embargo, es escaso el conocimiento que se tiene en el país de la problemática generada por la disposición en los cuerpos de agua de metales pesados y su impacto sobre el recurso íctico, el deterioro de ecosistemas y la salud humana. Con base en las normas vigentes se han realizado bioensayos como criterio para comprobar los efectos de la contaminación acuática con organismos dulceacuícolas y la evaluación de por lo menos tres parámetros (metales pesados, temperatura, efluentes, utilizando ocho especies de peces dulceacuícolas: Carassius auratus, Oreochromis spp., Piractus brachypomus, Prochilodus magdalenae, Astyanax

  19. Efeito anestésico do óleo de cravo em alevinos de lambari Anesthetic effect of clove oil on lambari

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    Elyara Maria Pereira-da Silva

    2009-09-01

    Full Text Available Para avaliar o efeito anestésico do óleo de cravo em lambaris (Astyanax altiparanae, cinco grupos de 30 alevinos (0,6±0,1g foram expostos às concentrações de 50, 75, 100, 125 e 150mg L-1, medindo-se, respectivamente: tempo de indução à anestesia profunda (caracterizada pela perda de equilíbrio, pela ausência de natação, pela redução dos movimentos operculares e pelas respostas apenas a estímulos táteis mais intensos, tempo de recuperação e taxa de mortalidade após a exposição. Em uma segunda etapa (10 peixes/tratamento, registraram-se, para cada concentração, os tempos de indução e de recuperação após anestesia cirúrgica (movimentos operculares lentos e irregulares e perda de reações a estímulos, anotando-se a mortalidade após seis minutos de exposição. Observou-se redução linear no tempo de indução à anestesia (0,01min mg-1 de anestésico acrescido e aumento quadrático do tempo de recuperação com a elevação da concentração (resposta máxima estimada em 7,1 minutos. A anestesia profunda foi alcançada em tempo inferior a 1,5 minuto para todas as concentrações, com recuperação mais rápida e sem mortalidade para 50mg L-1. Para indução à anestesia cirúrgica, foram registrados menores tempos nas concentrações 75 e 100mg L-1; porém, com mortalidade de 80% e 100%, respectivamente. A concentração 50mg L-1 promoveu anestesia cirúrgica e recuperação em 3,29±0,71 e 4,97±0,63 minutos, respectivamente, sem mortalidade. Concluiu-se que o óleo de cravo possui efeito anestésico para alevinos de lambari, sendo 50mg L-1 a concentração eficiente e segura para indução à anestesia profunda em até 1,5 minuto e de anestesia cirúrgica em até 3,3 minutos de exposição.The anesthetic effect of clove oil on lambari (Astyanax altiparanae was evaluated by exposing five groups of 30 fry (0.6±0.1g to concentrations of 50, 75, 100, 125 and 150mg L-1 and measuring the induction time to deep

  20. Ictiofauna de los humedales del río San Pedro, Balancán, Tabasco, México

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    Alfonso Castillo-Domínguez

    2011-06-01

    Full Text Available Los humedales de San Pedro sostienen redes tróficas del sistema fluvial debido a la alta disponibilidad de hábitats y a sus variaciones espacio-temporales. En esta investigación se estudió la composición, densidad y biomasa de la ictiofauna de los humedales; se capturaron 1 049 organismos de 25 especies, dos son exóticas: Oreochromis niloticus y Parachromis managuense. Con 23 especies capturadas en el sitio I, 17 en el II y 14 en el III. En la época de secas se obtuvo mayor riqueza con 21 especies, lluvias con 17 y cinco en nortes. La mayor densidad se mostró en el sitio II (0.23ind./m², seguido de los sitios I y III (0.12, 0.12ind./m². La mayor biomasa fue en secas (8.30g/m², seguida de lluvias (2.1g/m² y por último nortes (0.01g/m². La mayor densidad se mostró en secas (0.43ind./m² y la mínima en nortes (0.023ind./m². Las especies dominantes en densidad según el diagrama Olmstead-Tukey fueron: Petenia splendida, Vieja heterospila, Vieja synspila, Dorosoma petenense y Astyanax aeneus. Por lo tanto, existieron diferencias significativas en los parámetros ecológicos y ambientales. Al considerar la variación en la riqueza podemos concluir que los humedales del río San Pedro, es un sistema donde la composición de la ictiofauna responde a las fluctuaciones espaciales y temporales.Ichthyofauna from wetlands of San Pedro, Balancán, Tabasco, México. San Pedro River’s wetlands sustain trophic nets in the fluvial system, due to the high habitat availability, and space and temporal variations. In order to describe the relationship between environmental parameters and ichthyofauna, this study evaluated fish assemblages composition, distribution, abundance, density, biomass, richness species, diversity and equitability in the wetlands. Sampling considered three different sites and climatic seasons (dry, rainy and cold fronts. The physical and chemical parameters considered were dissolved oxygen, temperature, pH, water

  1. Níveis de energia digestível e proteína bruta em rações para alevinos de lambari tambiú Dietary levels of digestible energy and crude protein for lambari tambiú fingerlings

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    Jorge Luiz Vieira Cotan

    2006-06-01

    Full Text Available Com o objetivo de determinar os níveis de energia digestível (ED em função do nível de proteína bruta (PB da ração para alevinos de lambari tambiú (Astyanax bimaculatus, foram utilizados 600 peixes com 1,30 ± 0,01 g, distribuídos em 40 aquários de 100 L, dotados de abastecimento de água, com temperatura controlada e sistema de aeração individual. O experimento foi realizado em um esquema fatorial 5 x 2 (cinco níveis de ED: 2.900, 3.000, 3.100, 3.200 e 3.300 kcal/kg combinados com dois níveis de PB: 32,0 e 38,0%, em delineamento inteiramente ao acaso, com quatro repetições e 15 peixes por unidade experimental. Os peixes foram submetidos à alimentação controlada com base no consumo diário médio dos peixes dos tratamentos com rações contendo nível mais alto de energia (3.300 kcal/kg para cada nível protéico, corrigido diariamente, durante 49 dias. Foi avaliado o ganho de peso, a taxa de crescimento específico, os consumos de ração, de PB e de ED, a conversão alimentar, a taxa de eficiência protéica, o rendimento de carcaça, a eficiência de retenção de nitrogênio e os teores de umidade, proteína e gordura corporais. Com o nível de 32% de PB, foram obtidos maiores consumos de ração e de ED, mais altas taxas de eficiência protéica e de retenção de nitrogênio, menores consumo de PB e rendimento de carcaça, além de reduzida umidade corporal. Com níveis crescentes de ED nas rações com 32% de PB, os peixes apresentaram menor taxa de crescimento específico, mais baixa taxa de eficiência protéica e maior conversão alimentar, enquanto com as rações com 38% de PB apresentaram maior rendimento de carcaça. A exigência de ED para lambari tambiú é de 2.900 kcal/kg para rações com 32 e 38% de PB.Six hundred lambari tambiú (Astyanax bimaculatus averaging initial weight of 1.30 ± 0.01 g, placed in 40 aquariums (100 L with water renewal, controlled temperature and individual aeration, were used to

  2. Trophic structure of a fish community in Bananal stream subbasin in Brasília National Park, Cerrado biome (Brazilian Savanna, DF

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    Mariana Schneider

    2011-01-01

    Full Text Available The aim of this study was to determine the trophic structure of the fish community in the Bananal stream subbasin, which belongs to a well-preserved Cerrado area (Brazilian Savanna in Brasília National Park, Brazil. We also evaluated the influence of environmental variations in the diet of fish species. Four samples were taken in each 30 m long established transect, two in the rainy season and two in the dry season. A total of 1,050 stomachs of the 13 most abundant species were analyzed. A total of 36 food items were consumed, where 24 were autochthonous, 8 allochthonous, and 4 of undetermined origin. Non-metric multidimensional scaling (NMDS analysis, in addition to the results of frequency of occurrence and abundance charts, was used to determine four groups of feeding guilds: detritivores, omnivores (tending toward herbivory and invertivory, invertivores and piscivores. Around 69% of the volume of resources consumed was allochthonous, which proves the importance of the resources provided by riparian vegetation. The contribution of autochthonous and allochthonous items in the diet differed due to seasonality for Aspidoras fuscoguttatus, Astyanax sp., Characidium xanthopterum, Hyphessobrycon balbus, Kolpotocheirodon theloura, Moenkhausia sp., Phalloceros harpagos, and Rivulus pictus. Despite the Cerrado climate characteristics, there was no significant influence of season on the fish diet. The absence of seasonal variation and the predominance of allochthonous items in the fish diet are probably associated with the presence of riparian vegetation, which acts as a transition area in the Cerrado biome and provides resources for the aquatic fauna. This work shows the importance of studies in non-disturbed areas considered here as a source of information concerning the biology of fish species and as a guide for direct conservation policies on the management of aquatic resources, recovery of damaged areas and determination of priority areas for

  3. Feeding ecology of stream-dwelling fishes from a coastal stream in the Southeast of Brazil

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    Rosana Mazzoni

    2007-07-01

    Full Text Available The relationship between ontogenetic variation of intestine length and feeding habits of five stream-dwelling fish species from the Ubatiba River were investigated. Analysed data were based on two size categories (juveniles and adults and two food categories (animal and vegetal. Diet composition of each size category revealed that Astyanax janeiroensis and Geophagus brasiliensis changed food preference throughout ontogeny and switched from omnivorous/carnivorous to omnivorous/herbivorous and from omnivorous/carnivorous to omnivorous, respectively. These changes were followed by ontogenetic changes in the Intestinal Coefficient (IC. No ontogenetic differences were registered for IC and food categories consumed by Hoplias malabaricus but significant differences in the size of consumed preys as well as positive correlation between fish size (predator and prey size was observed. Food items (within animal category consumed by the adult Pimelodella lateristriga were mainly based on allochthonous arthropods whereas juvenile individuals fed with the same intensity on allochthonous and autochthonous arthropods; both juveniles and adult individuals of Mimagoniates microlepis were mainly allochthonous feeders. Mean IC values of Pimelodella lateristriga and Mimagoniates microlepis did not change along body growth. Although changes in food category consumption were not common among all the studied species, changes in the resource exploitation strategy was a rule among them, except for Mimagoniates microlepis.Foi investigada a relação entre as variações ontogenéticas do comprimento do intestino e os hábitos alimentares de cinco espécies de peixes do rio Ubatiba, RJ. Os dados analisados foram baseados em duas categorias de tamanho (jovens e adultos de cada espécie e duas categorias de alimento (animal e vegetal. A composição da dieta de cada categoria de tamanho revelou que Astyanax janeiroensis e Geophagus brasiliensis mudaram a prefer

  4. Estado del conocimieno de las concentraciones de mercurio y otros metales pesados en peces dulceacuícolas de Colombia Current State of Knowledge of the Concentration of Mercury and Other Heavy Metals in Fresh Water Fish in Colombia

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    Álvarez-León Ricardo

    2006-06-01

    Full Text Available Una de las problemáticas ambientales más importantes en el país se refiere al uso indiscriminado de precursores químicos en actividades ilícitas, el uso de metales pesados como mercurio en actividades mineras, el vertimiento de aguas servidas y otro tipo de compuestos relacionados con actividades industriales y prácticas agrícolas inadecuadas. Lo anterior, ha llevado a que la contaminación química en especial por metales pesados, constituya una de las más peligrosas para los ecosistemas acuáticos y las especies presentes en ellos. Los peces tienen la capacidad de almacenar en su organismo una concentración mayor de estos compuestos en comparación con la presente en el medio, por lo que son un indicador importante de la contaminación, pero también esto implica que su consumo se puede convertir en un problema de salud para las poblaciones que se alimentan de este recurso. La concentración de metales pesados en peces de agua dulce es conocida de mejor manera en la cuenca del río Magdalena, especialmente en la región de la Mojana y en las ciénagas del sur del departamento de Bolívar donde se han estudiado los niveles de contaminación por mercurio y otros metales producida por el desarrollo de múltiples actividades  industriales, entre las cuales sobresalen la minería de oro y la petroquímica. Sin embargo, es escaso el conocimiento que se tiene en el país de la problemática generada por la disposición en los cuerpos de agua de metales pesados y su impacto sobre el recurso íctico, el deterioro de ecosistemas y la salud humana. Con base en las normas vigentes se han realizado bioensayos como criterio para comprobar los efectos de la contaminación acuática con organismos dulceacuícolas y la evaluación de por lo menos tres parámetros (metales pesados, temperatura, efluentes, utilizando ocho especies de peces
    dulceacuícolas: Carassius auratus, Oreochromis spp., Piractus brachypomus, Prochilodus magdalenae, Astyanax

  5. Viirastuse ja illusiooni vahel: Trooja Jean Racine’i traagilises dispositiivis / Between Delusion and Illusion: Troy in Jean Racine’s Tragic Dispositive

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    Maria Einman

    2014-12-01

    Full Text Available This paper explores the role of Troy in the space-time continuum of Jean Racine’s (1639-1699 two most widely known, secular tragedies „Iphigenia“ (1667 and „Andromache“ (1674. The tragic space-time continuum and its effect on the image of Troy is analysed according to the theory of operative devices. Stéphane Lojkine adapted this theory to the analysis of the space created by fictional texts. In the first section, the paper gives a brief overview of the history of the theory of operative devices and the principles and primary concepts involved, then describes the space-time of Racine’s tragedy as an operative device, which functions because the tensions created between the different zones and levels of space-time are mediated on a scopic level (i.e. the character’s viewpoints. The second section takes a closer look at how the images of the Trojan War that are created shift and change within these zones, depending on whether the events of war take place in the present or the future vis-à-vis the events of the tragedy.  In „Andromache“, Troy has already been destroyed. One of the Greek commanders, King Pyrrhus, is driven by sentimentality and wishes to restore it „within the walls“ of his kingdom. However, in „Iphigenia“, the characters are only just making preparations for war and their main desire is to be free of the curse of the gods that has rendered the waterway leading under the walls of Troy impenetrable. The male protagonists of both tragedies wish to bring Troy into their own, present space-time continuum. The conflicts in both tragedies revolve around a character who is the „key“ to Troy: in „Andromache“, it is Astyanax, the son of Hector, the dead king of Troy, and in „Iphigenia“, it is the main character’s double, Eriphyle, the daughter of beautiful Helen and Theseus. The delusional city in „Andromache“ materializes when Pyrrhus places the crown on Andromaque’s head, thereby ensuring