Navegando por Assunto "Arapaima gigas"

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Acesso aberto (Open Access)
Análise e caracterização do genoma mitocondrial: um estudo de caso de Cyprinodon sp. e Arapaima gigas
(Universidade Federal do Pará, 2025-05) MACEDO, Daralyns Borges; RAMOS, Rommel Thiago Juca; http://lattes.cnpq.br/1274395392752454; https://orcid.org/0000-0002-8032-1474
The advancement of next-generation sequencing technologies has enabled large-scale characterization of mitochondrial genomes across various species. However, even among fish — the group with the highest number of sequenced mitochondrial genomes — only 9.7% of valid species are represented in genetic databases. This gap limits conservation programs, which rely on genetic data to guide management strategies. The genus Cyprinodon, composed of several threatened species restricted to isolated habitats, is particularly vulnerable to habitat loss and interspecific hybridization. In this context, the present study aimed to sequence and characterize the mitochondrial genome of Cyprinodon sp., in order to clarify phylogenetic relationships and evolutionary aspects of the Cyprinodontidae family. The sample was sequenced using the Illumina HiSeq platform, assembled with Megahit software, and analyzed using tools such as MitoZ, Circos, ClustalW, MrBayes, and Figtree. The complete mitogenome comprises 16,500 bp and contains 37 genes. Concurrently, Arapaima gigas, an iconic Amazonian species historically important to fisheries, is currently threatened with extinction and classified as “Data Deficient” by the IUCN. In the Tocantins River, heavily impacted by human activities, fishers from 25 communities reported the near disappearance of the species, with only one recent sighting on Jaracuera Island. The disappearance of A. gigas has severe economic consequences for local communities. Without collaboration between fishery managers and local populations, the species faces an imminent risk of regional extinction, further exacerbated by the lack of data on its fishing dynamics in northern Brazil.
Acesso aberto (Open Access)
Crescimento e produção de pirarucu, Arapaima gigas, sob diferentes densidades de estocagem em associação com búfalas leiteiras
(Universidade Federal do Pará, 2001-10) IMBIRIBA, Emir Palmeira; LOURENÇO JÚNIOR, José de Brito; http://lattes.cnpq.br/2919433679918544
With the objective of evaluating four stock densities of pirarucu (Arapaima gigas) and to identify the one that provides the best productive performance, in length and weight gain to make possible its intensive culture, a research was carried out, during 360 days. using the densities of 5, 10, 15 and 20 fishes per 100 m2 of inundate area. Live tilapias (Tilapia nilotica), captured in a dam used for milk buffaloes management, equivalent to 6% of the pirarucu live weight, were used during four days per week. The design was completely randomized with four treatments and two replications. The data were analyzed on the basis of the application of the exponential model of growth. Mathematical expressions were obtained for each stockage density. Simple linear regression analysis were made. - However, until the first 120 days, no significant difference in weight could be observed among the four study densities. The values of the angular coefficient of the relation weight/length of pirarucu showed that its growth is of the allometric type. The maximum total size was 107.66 cm and the maximum weight was 13.43 kg, in the density of five fishes per 100 m2. However, the highest biomass, of 85.69 kg per 100 m2, was observed in the density of 10 fishes per 100 m2, suggesting that this density would be the most adequate for using in intensive systems. The excellent ponderal development of pirarucu, indicates the potential use of this species, in intensive systems associated with buffaloes.
Acesso aberto (Open Access)
Genética de populações de pirarucus (Arapaima gigas) da Reserva Mamirauá e considerações sobre estrutura genética para a espécie
(Universidade Federal do Pará, 2008-10-24) SILVA, Juliana Araripe Gomes da; SCHNEIDER, Horacio; http://lattes.cnpq.br/3621033429800270
The pirarucu (Arapaima gigas) is an important fishing resource in the Amazon which has been exploited since the XIXth century. There are indications of a decrease in population size in some parts of its distribution. Management is one of the strategies adopted to maintain fishing activity associated to the conservation of the species. We evaluate aspects of pirarucu populations in two places in the Mamirauá Reserve (Jarauá and Maraã), and compare these populations with those of Santarém and Tucuruí, analyzing their genetic variability and structure. In order to achieve this, seven microsatellite loci were genotyped for 463 pirarucus from Mamirauá Reserve collected along five years. Our results show a greater genetic diversity for this population in comparison to populations from Santarém and Tucuruí. Analyses indicate that management has been ecologically efficient, since there were no significant change in genetic diversity over the five years of study. Lateral migration, associated with a possible standardized return to lakes without spacial fidelity seems to have great importance for local genetic admixture. However, this admixture is limited in space, with a small degree of genetic differentiation seem between pirarucus from Jarauá and Maraã. When including more distant localities to the analysis, the differentiation is greater though geographic distance cannot explain all of this. We believe that a population decline in intermediate localities, probably caused by overexploiting is influencing the connectivity among the localities studied.