Centromochlus meridionalis was recently described from streams of Brazilian Amazon. The marbled d... more Centromochlus meridionalis was recently described from streams of Brazilian Amazon. The marbled dark brown and black color pattern together with the use of submersed leaf litter accumulations for shelter differentiates this species among its congeners. We present information about the biology of C. meridionalis based on data gathered in streams and under captivity, as well as on a dietary analysis. Behavioral observations were made in captivity (aquaria). Dietary analysis was performed based on stomach contents of 38 specimens. The species was found in 8 out of 12 small streams sampled, where specimens were captured predominantly amidst submerged leaf litter. Nine types of behavioral acts were identified, of which “swimming near the substratum” and “charging the substratum for food” were the most frequent. Thirty (~ 79 %) out of the 38 stomachs had food, and the diet was composed of 27 types of food items. Centromochlus meridionalis can be considered a generalist microcarnivore, con...
A aquicultura é a atividade que mais cresce entre os setores de produção de alimentos, porém, se ... more A aquicultura é a atividade que mais cresce entre os setores de produção de alimentos, porém, se executada inadequadamente, pode causar a deterioração da qualidade da água. O objetivo do trabalho foi avaliar a utilização do Índice de Estado Trófico (IET) como ferramenta de monitoramento de atividades aquícolas, especificamente do Parque Aquícola Sucupira, área de cultivo de peixes em tanques-rede no reservatório do Lajeado em Palmas/TO. O monitoramento foi realizado entre janeiro e agosto de 2017, envolvendo a coleta de amostras para análises dos parâmetros de fósforo total e clorofila-a. Paralelamente, houve coleta de dados de temperatura, turbidez, oxigênio dissolvido, condutividade, pH e sólidos totais dissolvidos. As variáveis limnológicas (temperatura, condutividade, turbidez, oxigênio dissolvido, pH e sólidos totais dissolvidos), com exceção do fósforo total, apesar das pequenas variações de oxigênio e sólidos totais, estão de acordo com as recomendações da Resolução CONAMA 35...
A new species of Pimelodella is described from the Rio Ipitinga, Rio Jari basin, a left bank trib... more A new species of Pimelodella is described from the Rio Ipitinga, Rio Jari basin, a left bank tributary of the Rio Amazonas in Brazil. The new species is diagnosed from all congeners by having a dark oval mark on the humeral region. It also differs from all congeners by a unique set of characters, including the presence of 47 to 49 total vertebrae, unpigmented areas dorsally and ventrally adjacent to the dark midlateral stripe, and maxillary barbels reaching at least to vertical through caudal fin insertion. Faunal similarities between the southern part of the eastern Guiana Shield and coastal drainages in the Guianas and Suriname are discussed.
New data are presented on the sex chromosomes of the fish species Eigenmannia virescens (Gymnotif... more New data are presented on the sex chromosomes of the fish species Eigenmannia virescens (Gymnotiformes, Sternopygidae). A new finding, involving the occurrence of ZZ/ZW sex chromosomes, is described in specimens sampled from the São Francisco and Amazon river basins in Brazil. All individuals had a chromosome number of 2n = 38. The homologs of the sex chromosome pair from the São Francisco river basin sample differed only in their morphology, while those from the Amazonian sample differed both in morphology and heterochromatin pattern. A possible model for the evolution of the sex chromosomes in E. virescens is proposed, including data from populations from the Paraná (Brazil) river basin, in which male heterogamety has already been described. The occurrence of different sex chromosome systems in species and populations of the neotropical freshwater fish fauna is discussed.
Introducão O rio Tocantins, com 2.750 km de extensão, nasce no Planalto Central Brasileiro e flui... more Introducão O rio Tocantins, com 2.750 km de extensão, nasce no Planalto Central Brasileiro e flui no sentido sul-norte, desaguando no rio Pará, estuário do Amazonas. Seu maior tributário, o rio Araguaia, com 2.200 km de extensão, também tem sua origem no Planalto Central, correndo paralelamente e desaguando pouco acima da cidade de Marabá. O rio Tocantins, na maior parte de seu curso, flui encaixado e muitas de suas lagoas têm contato com o canal principal do rio somente em anos de grandes cheias (Goulding et al., 2003). O rio Tocantins é classificado como rio de água clara (Sioli, 1950, 1984), cuja vazão anual média está entre 10.000 e 11.000 m 3 /s. As variações na descarga do rio são grandes e o débito máximo pode ser dez vezes superior ao mínimo. Muitos tributários de pequeno e médio porte, no alto e médio Tocantins, são temporários e, freqüentemente, se apresentam completamente secos ou com fluxo parcialmente interrompido durante a maior parte do ano. No período das chuvas, o n...
The ichthyofauna of 24 stretches of streams, all of 100 m length and of fi fth or lower order and... more The ichthyofauna of 24 stretches of streams, all of 100 m length and of fi fth or lower order and most of second and third order, were sampled along four left bank tributaries (Rio do Peixe, Rio Aguapeí, Rio São José dos Dourados, lower Rio Tietê) of the main channel of the Rio Paraná in the state of São Paulo, southeastern Brazil. Sampling of the fi sh fauna at each of the six sites in the four basins incorporated a standardized fi sh collecting methodology and a standardized documentation of environmental data serving as the basis for a comparative analysis of the collecting locations. The 8,189 fi sh specimens collected represented six orders, 18 families, 42 genera, and 56 species, with a total biomass of 28.8 kg. Approximately 52 % of the collected species were characiforms, 28 % siluriforms, 9 % gymnotiforms, 5 % cyprinodontiforms, 4 % perciforms, and 2 % synbranchiforms. The most abundant of the species were the characiforms Astyanax altiparanae (15 % of total) and Knodus moe...
Centromochlus meridionalis was recently described from streams of Brazilian Amazon. The marbled d... more Centromochlus meridionalis was recently described from streams of Brazilian Amazon. The marbled dark brown and black color pattern together with the use of submersed leaf litter accumulations for shelter differentiates this species among its congeners. We present information about the biology of C. meridionalis based on data gathered in streams and under captivity, as well as on a dietary analysis. Behavioral observations were made in captivity (aquaria). Dietary analysis was performed based on stomach contents of 38 specimens. The species was found in 8 out of 12 small streams sampled, where specimens were captured predominantly amidst submerged leaf litter. Nine types of behavioral acts were identified, of which “swimming near the substratum” and “charging the substratum for food” were the most frequent. Thirty (~ 79 %) out of the 38 stomachs had food, and the diet was composed of 27 types of food items. Centromochlus meridionalis can be considered a generalist microcarnivore, con...
Centromochlus meridionalis was recently described from streams of Brazilian Amazon. The marbled d... more Centromochlus meridionalis was recently described from streams of Brazilian Amazon. The marbled dark brown and black color pattern together with the use of submersed leaf litter accumulations for shelter differentiates this species among its congeners. We present information about the biology of C. meridionalis based on data gathered in streams and under captivity, as well as on a dietary analysis. Behavioral observations were made in captivity (aquaria). Dietary analysis was performed based on stomach contents of 38 specimens. The species was found in 8 out of 12 small streams sampled, where specimens were captured predominantly amidst submerged leaf litter. Nine types of behavioral acts were identified, of which “swimming near the substratum” and “charging the substratum for food” were the most frequent. Thirty (~ 79 %) out of the 38 stomachs had food, and the diet was composed of 27 types of food items. Centromochlus meridionalis can be considered a generalist microcarnivore, con...
A aquicultura é a atividade que mais cresce entre os setores de produção de alimentos, porém, se ... more A aquicultura é a atividade que mais cresce entre os setores de produção de alimentos, porém, se executada inadequadamente, pode causar a deterioração da qualidade da água. O objetivo do trabalho foi avaliar a utilização do Índice de Estado Trófico (IET) como ferramenta de monitoramento de atividades aquícolas, especificamente do Parque Aquícola Sucupira, área de cultivo de peixes em tanques-rede no reservatório do Lajeado em Palmas/TO. O monitoramento foi realizado entre janeiro e agosto de 2017, envolvendo a coleta de amostras para análises dos parâmetros de fósforo total e clorofila-a. Paralelamente, houve coleta de dados de temperatura, turbidez, oxigênio dissolvido, condutividade, pH e sólidos totais dissolvidos. As variáveis limnológicas (temperatura, condutividade, turbidez, oxigênio dissolvido, pH e sólidos totais dissolvidos), com exceção do fósforo total, apesar das pequenas variações de oxigênio e sólidos totais, estão de acordo com as recomendações da Resolução CONAMA 35...
A new species of Pimelodella is described from the Rio Ipitinga, Rio Jari basin, a left bank trib... more A new species of Pimelodella is described from the Rio Ipitinga, Rio Jari basin, a left bank tributary of the Rio Amazonas in Brazil. The new species is diagnosed from all congeners by having a dark oval mark on the humeral region. It also differs from all congeners by a unique set of characters, including the presence of 47 to 49 total vertebrae, unpigmented areas dorsally and ventrally adjacent to the dark midlateral stripe, and maxillary barbels reaching at least to vertical through caudal fin insertion. Faunal similarities between the southern part of the eastern Guiana Shield and coastal drainages in the Guianas and Suriname are discussed.
New data are presented on the sex chromosomes of the fish species Eigenmannia virescens (Gymnotif... more New data are presented on the sex chromosomes of the fish species Eigenmannia virescens (Gymnotiformes, Sternopygidae). A new finding, involving the occurrence of ZZ/ZW sex chromosomes, is described in specimens sampled from the São Francisco and Amazon river basins in Brazil. All individuals had a chromosome number of 2n = 38. The homologs of the sex chromosome pair from the São Francisco river basin sample differed only in their morphology, while those from the Amazonian sample differed both in morphology and heterochromatin pattern. A possible model for the evolution of the sex chromosomes in E. virescens is proposed, including data from populations from the Paraná (Brazil) river basin, in which male heterogamety has already been described. The occurrence of different sex chromosome systems in species and populations of the neotropical freshwater fish fauna is discussed.
Introducão O rio Tocantins, com 2.750 km de extensão, nasce no Planalto Central Brasileiro e flui... more Introducão O rio Tocantins, com 2.750 km de extensão, nasce no Planalto Central Brasileiro e flui no sentido sul-norte, desaguando no rio Pará, estuário do Amazonas. Seu maior tributário, o rio Araguaia, com 2.200 km de extensão, também tem sua origem no Planalto Central, correndo paralelamente e desaguando pouco acima da cidade de Marabá. O rio Tocantins, na maior parte de seu curso, flui encaixado e muitas de suas lagoas têm contato com o canal principal do rio somente em anos de grandes cheias (Goulding et al., 2003). O rio Tocantins é classificado como rio de água clara (Sioli, 1950, 1984), cuja vazão anual média está entre 10.000 e 11.000 m 3 /s. As variações na descarga do rio são grandes e o débito máximo pode ser dez vezes superior ao mínimo. Muitos tributários de pequeno e médio porte, no alto e médio Tocantins, são temporários e, freqüentemente, se apresentam completamente secos ou com fluxo parcialmente interrompido durante a maior parte do ano. No período das chuvas, o n...
The ichthyofauna of 24 stretches of streams, all of 100 m length and of fi fth or lower order and... more The ichthyofauna of 24 stretches of streams, all of 100 m length and of fi fth or lower order and most of second and third order, were sampled along four left bank tributaries (Rio do Peixe, Rio Aguapeí, Rio São José dos Dourados, lower Rio Tietê) of the main channel of the Rio Paraná in the state of São Paulo, southeastern Brazil. Sampling of the fi sh fauna at each of the six sites in the four basins incorporated a standardized fi sh collecting methodology and a standardized documentation of environmental data serving as the basis for a comparative analysis of the collecting locations. The 8,189 fi sh specimens collected represented six orders, 18 families, 42 genera, and 56 species, with a total biomass of 28.8 kg. Approximately 52 % of the collected species were characiforms, 28 % siluriforms, 9 % gymnotiforms, 5 % cyprinodontiforms, 4 % perciforms, and 2 % synbranchiforms. The most abundant of the species were the characiforms Astyanax altiparanae (15 % of total) and Knodus moe...
Centromochlus meridionalis was recently described from streams of Brazilian Amazon. The marbled d... more Centromochlus meridionalis was recently described from streams of Brazilian Amazon. The marbled dark brown and black color pattern together with the use of submersed leaf litter accumulations for shelter differentiates this species among its congeners. We present information about the biology of C. meridionalis based on data gathered in streams and under captivity, as well as on a dietary analysis. Behavioral observations were made in captivity (aquaria). Dietary analysis was performed based on stomach contents of 38 specimens. The species was found in 8 out of 12 small streams sampled, where specimens were captured predominantly amidst submerged leaf litter. Nine types of behavioral acts were identified, of which “swimming near the substratum” and “charging the substratum for food” were the most frequent. Thirty (~ 79 %) out of the 38 stomachs had food, and the diet was composed of 27 types of food items. Centromochlus meridionalis can be considered a generalist microcarnivore, con...
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