Navegando por Assunto "Ictiologia"

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Acesso aberto (Open Access)
Efeito da perda de cobertura florestal sobre a diversidade de peixes de riachos em uma zona de transição Cerrado-Amazônia
(Universidade Federal do Pará, 2019-02-28) FREITAS, Pâmela Virgolino; JIQUIRIÇÁ, Paulo Ricardo Ilha; http://lattes.cnpq.br/3392388693636935; SILVA, Karina Dias da; http://lattes.cnpq.br/2271768102150398
Currently, the expansion of the agricultural frontier in the Amazon represents a profound change in the world’s vegetation cover. This expansion causes decrease of forest cover, affecting the environmental integrity of streams, as well as the richness of associated communities. We aimed to evaluate the effects of loss of forest cover on the physical integrity of streams, and on the taxonomic and functional diversity of fish assemblages in a Cerrado-Amazon transitional zone. We sampled nine streams in the Alto Xingu river basin. The streams possess microbasins covered by different percentages of transitional Cerrado-Amazon forest and croplands. We did not detect the effect of loss of forest cover on the physical integrity of streams, and neither on fish taxonomic diversity. However, we found a negative effect on the functional diversity. The physical integrity of streams was not associated with taxonomic and functional diversity of fish assemblages. The conversion of forest areas to croplands, on the riparian zone, affects negatively the functional richness of fish assemblages, acting as an environmental filter, leading to the disappearance of species that could have performed important ecosystem functions. Furthermore, the establishment of restoring and conservation strategies of areas affected by deforestation must be a priority on all streams drainage systems, especially on the riparian zone scale, to minimize impacts on species. To understand which factors can better structure fish assemblages in streams, it is necessary to do research, that can give basis to formulate strategies for the preservation of those organisms.
Acesso aberto (Open Access)
First occurrence of Quadrigyrus nickoli (Acanthocephala) in the ornamental fish Hyphessobrycon eques
(2013-03) FUJIMOTO, Rodrigo Yudi; SARMENTO, Aline de Melo Braun; DINIZ, Daniel Guerreiro; EIRAS, Jorge Costa; MARTINS, Maurício Laterça
The objective of this work was to report the first seasonal occurrence of the acanthocephalan Quadrigyrus nickoli Schmidt & Hugghins, 1973 (Quadrigyridae), in the “Mato Grosso” Hyphessobrycon eques (Characidae) (Steindachner, 1882), collected from the Chumucuí River, state of Pará, Brazil. The fish were collected between July 2006 (rainy season) and June 2007 (dry season) and were examined for parasites using pattern techniques. A total of 75 parasites were found in the stomach and intestine. Among 83 fish examined (50 in the dry season and 33 in the rainy season), 22 were parasitized by cystacanths of Q. nickoli. The importance of H. eques as a paratenic host for Q. nickoli is discussed. This is the first study on the biology of and infection by Q. nickoli occurring in the eastern Amazon region.
Acesso aberto (Open Access)
Sistemática das espécies de cascudos “acari-cachimbo” do gênero Hemiodontichthys bleeker, 1862 (Siluriformes: Loricariidae) com a descrição de quatro espécies novas
(Universidade Federal do Pará, 2012) MENDONÇA, Marina Barreira; WOSIACKI, Wolmar Benjamin; http://lattes.cnpq.br/0040413891328104
The taxonomic revision of the genus Hemiodontichthys Bleeker, 1862 resulted in the recognition of five valid species, including four new species. A new diagnosis for the genus is provided, H. acipenserinus is redescribed, an identification key is included, and a distribution map for the genus is provided. Hemiodontichthys sp. “Coari” occurs in the Urucu basin, Hemiodontichthys sp. “Tocantins” in the Tocantins drainages, Hemiodontichthys sp. “Peru1” in the Madre de Dios , Ucayali and Nanay rivers, on Peru, Hemiodontichthys sp. “Peru2” has an inaccurate location on Iquitos, and the type-species H. acipenserinus, occurs on Guaporé river, Madeira river, and in the middle and lower Amazon river. Comments about the monophyly of Hemiodonthichthys are presented.
Acesso aberto (Open Access)
Variação geográfica em Schizodon dissimilis (Garman, 1890) e diversidade genética e filogeográfica do grupo Schizodon fasciatus sensu lato (Characiformes: Anostomidae)
(Universidade Federal do Pará, 2013) ABREU, João Marcelo da Silva; SCHNEIDER, Horacio; http://lattes.cnpq.br/3621033429800270