Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Mais filtros

Base de dados
Ano de publicação
Tipo de documento
Intervalo de ano de publicação
1.
Artigo em Inglês | VETINDEX | ID: vti-690446

Resumo

This study analyzed the diet and reproductive dynamics of Trachelyopterus lucenai Bertoletti, Pezzi da Silva & Pereira, 1995, an allochthonous fish species in the subtropical coastal lagoons of the Tramandaí River, Rio Grande do Sul, Brazil. The fecundity of the species is described for the first time. Specimens were captured in the interconnected lagoons Itapeva, Quadros and Malvas, on a monthly basis, from November 2008 to April 2010, with gillnets of different mesh sizes. The food items identified were assessed for abundance and frequency of occurrence. The sex ratio, reproductive period for males and females, for mature females, fecundity, were estimated. These results were analyzed with respect to seasonal variation. We captured 135 individuals, including 82 females and 53 males, especially in months with high temperatures (October 2009 to March 2010). Females were more abundant than males in all months. There was no difference between the mean size of females and males, and both sexes showed allometric growth. The feeding analysis showed a generalist-opportunist food habit; 26 items were consumed, with a predominance of autochthonous items (insects and fish). Temporal variations in diet were associated with variations in water and air temperature and rainfall in the region, but these variations did not differ between males and females. The sex ratio differed significantly from 1:1, with 1.5 females per male. The reproductive period occurred from October to March, with most activity in November and December, and showing no variation between the peaks of gonadal development of males and females. The mean fecundity of mature females was 1,536 oocytes per spawning (n = 17). The feeding habits and reproductive behavior of the species in the study site are similar to those described for where the species is native. Although clearly seasonal, the reproductive period was long, in spite of the low fecundity. These features facilitate the establishment of T. lucenai and make it a good competitor in the new environment.

2.
Artigo em Inglês | LILACS-Express | VETINDEX | ID: biblio-1504158

Resumo

This study analyzed the diet and reproductive dynamics of Trachelyopterus lucenai Bertoletti, Pezzi da Silva & Pereira, 1995, an allochthonous fish species in the subtropical coastal lagoons of the Tramandaí River, Rio Grande do Sul, Brazil. The fecundity of the species is described for the first time. Specimens were captured in the interconnected lagoons Itapeva, Quadros and Malvas, on a monthly basis, from November 2008 to April 2010, with gillnets of different mesh sizes. The food items identified were assessed for abundance and frequency of occurrence. The sex ratio, reproductive period for males and females, for mature females, fecundity, were estimated. These results were analyzed with respect to seasonal variation. We captured 135 individuals, including 82 females and 53 males, especially in months with high temperatures (October 2009 to March 2010). Females were more abundant than males in all months. There was no difference between the mean size of females and males, and both sexes showed allometric growth. The feeding analysis showed a generalist-opportunist food habit; 26 items were consumed, with a predominance of autochthonous items (insects and fish). Temporal variations in diet were associated with variations in water and air temperature and rainfall in the region, but these variations did not differ between males and females. The sex ratio differed significantly from 1:1, with 1.5 females per male. The reproductive period occurred from October to March, with most activity in November and December, and showing no variation between the peaks of gonadal development of males and females. The mean fecundity of mature females was 1,536 oocytes per spawning (n = 17). The feeding habits and reproductive behavior of the species in the study site are similar to those described for where the species is native. Although clearly seasonal, the reproductive period was long, in spite of the low fecundity. These features facilitate the establishment of T. lucenai and make it a good competitor in the new environment.

3.
Artigo em Inglês | VETINDEX | ID: vti-441406

Resumo

This study analyzed the diet and reproductive dynamics of Trachelyopterus lucenai Bertoletti, Pezzi da Silva & Pereira, 1995, an allochthonous fish species in the subtropical coastal lagoons of the Tramandaí River, Rio Grande do Sul, Brazil. The fecundity of the species is described for the first time. Specimens were captured in the interconnected lagoons Itapeva, Quadros and Malvas, on a monthly basis, from November 2008 to April 2010, with gillnets of different mesh sizes. The food items identified were assessed for abundance and frequency of occurrence. The sex ratio, reproductive period for males and females, for mature females, fecundity, were estimated. These results were analyzed with respect to seasonal variation. We captured 135 individuals, including 82 females and 53 males, especially in months with high temperatures (October 2009 to March 2010). Females were more abundant than males in all months. There was no difference between the mean size of females and males, and both sexes showed allometric growth. The feeding analysis showed a generalist-opportunist food habit; 26 items were consumed, with a predominance of autochthonous items (insects and fish). Temporal variations in diet were associated with variations in water and air temperature and rainfall in the region, but these variations did not differ between males and females. The sex ratio differed significantly from 1:1, with 1.5 females per male. The reproductive period occurred from October to March, with most activity in November and December, and showing no variation between the peaks of gonadal development of males and females. The mean fecundity of mature females was 1,536 oocytes per spawning (n = 17). The feeding habits and reproductive behavior of the species in the study site are similar to those described for where the species is native. Although clearly seasonal, the reproductive period was long, in spite of the low fecundity. These features facilitate the establishment of T. lucenai and make it a good competitor in the new environment.

4.
Artigo em Português | VETINDEX | ID: vti-437709

Resumo

This study presents the composition of species, the distribution and dominance patterns, and the structure of sizes of the assemblage of fish in distinct habitats (littoral, deeper and near shore limnetic zone) of the Mangueira lake, in the southern Brazil. Samples were taken in the north, south and central regions of the lake from 2001 to 2007 using a multi-gear approach (gillnet, cast net, beach seine, dip net and bottom trawling). A total of 52 species were identified, 46 in the littoral zone, 33 in the near shore limnetic zone and 26 in the deep zone, distributed in 17 families, of the which, Characidae, Cichlidae, Loricariidae, and Atherinopsidae were the most diverse. The dominant species summed up 91.1 %, 92.9 % and 82.7 % of the all individuals caught in the littoral, deeper and limnetic zone, respectively. The littoral zone was comprised of small fishes, nearly 70 % between 25 and 50 TL mm. The dominance patterns showed that, in this zone, 19,5 % of the species were dominant, although four of those also prevailed in the other zones. In the deep zone, 7,6% of the captured species were dominant, with similar sizes to the littoral zone. For the other species, the sizes resemble to the near shore limnetic zone. The near shore limnetic zone was comprised of larger fishes, the major part between 150 and 200 TL mm, such as the great characins, the toothless characin and the silverside fishes. A larger difference was observed in the composition of species between the littoral and limnetic zones, with the species Jenynsia multidentata, Bryconamericus iheringii, Hyphessobrycon luetkenii and Gymnogeophagus gymnogenys dominating exclusively in the littoral, and the species Oligosarcus jenynsii, Cyphocharax voga, Odontesthes perugiae and Astyanax fasciatus dominating exclusively the near shore limnetic zone. The littoral zone presented differences in the composition and dominance of the species among the portions north and south of the lake. The 52 species registered in this study represent a high diversity of fishes in Mangueira lake, specially when compared to other coastal lakes of RS. Differentiated patterns of composition and abundance of species seem to reflect characteristics different from the coastal habitats sampled.


Este estudo apresenta a composição de espécies, os padrões de distribuição e dominância, e a estrutura de tamanhos da assembleia de peixes em diferentes unidades de hábitat (zonas litoral, profunda e limnética costeira) da lagoa Mangueira, no extremo sul do Brasil. As amostras foram obtidas no norte, centro e sul da lagoa, entre os anos de 2001 e 2007 utilizando-se de diversos amostradores (rede de emalhe, tarrafa, rede de arrasto de praia, puçá e rede de arrasto de fundo). Um total de 52 espécies foi identificado, 46 na zona litoral, 33 na limnética costeira e 26 na profunda, distribuídas em 17 famílias, das quais, Characidae, Cichlidae, Loricariidae e Atherinopsidae foram as mais diversas. As espécies dominantes somaram 91,1 %, 92,9 % e 82,7 % dos indivíduos capturados nas zonas litoral, profunda e limnética costeira respectivamente. A zona litoral é constituída de pequenos peixes, quase 70 % entre 25 e 50 mm de comprimento. Os padrões de dominância mostraram que, nesta zona, 19,5 % das espécies foram dominantes, embora quatro dessas também predominaram nas demais zonas. Na zona profunda, 7,6 % das espécies capturadas foram dominantes, com tamanhos semelhantes aos da zona litoral. Para as demais espécies, os tamanhos se assemelham aos da zona limnética costeira. A zona limnética costeira é constituída de peixes de maior porte, a maioria entre 150 e 200 mm de comprimento total, tais como os grandes caracídeos, o birú e os peixes-rei. Observou-se uma maior diferença na composição de espécies entre as zonas litoral e limnética costeira, com as espécies Jenynsia multidentata, Bryconamericus iheringii, Hyphessobrycon luetkenii e Gymnogeophagus gymnogenys dominando exclusivamente no litoral, e as espécies Oligosarcus jenynsii, Cyphocharax voga, Odontesthes perugiae e Astyanax fasciatus dominando exclusivamente a zona limnética costeira. A zona litoral apresentou diferenças na composição e dominância das espécies entre as porções norte e sul da lagoa. As 52 espécies registradas neste estudo representam uma alta riqueza de peixes na lagoa Mangueira, sobretudo quando comparada a outras lagoas costeiras do RS. Padrões diferenciados de composição e abundância de espécies parecem refletir características distintas dos habitats litorâneos amostrados.

5.
Artigo em Português | LILACS-Express | VETINDEX | ID: biblio-1484106

Resumo

This study presents the composition of species, the distribution and dominance patterns, and the structure of sizes of the assemblage of fish in distinct habitats (littoral, deeper and near shore limnetic zone) of the Mangueira lake, in the southern Brazil. Samples were taken in the north, south and central regions of the lake from 2001 to 2007 using a multi-gear approach (gillnet, cast net, beach seine, dip net and bottom trawling). A total of 52 species were identified, 46 in the littoral zone, 33 in the near shore limnetic zone and 26 in the deep zone, distributed in 17 families, of the which, Characidae, Cichlidae, Loricariidae, and Atherinopsidae were the most diverse. The dominant species summed up 91.1 %, 92.9 % and 82.7 % of the all individuals caught in the littoral, deeper and limnetic zone, respectively. The littoral zone was comprised of small fishes, nearly 70 % between 25 and 50 TL mm. The dominance patterns showed that, in this zone, 19,5 % of the species were dominant, although four of those also prevailed in the other zones. In the deep zone, 7,6% of the captured species were dominant, with similar sizes to the littoral zone. For the other species, the sizes resemble to the near shore limnetic zone. The near shore limnetic zone was comprised of larger fishes, the major part between 150 and 200 TL mm, such as the great characins, the toothless characin and the silverside fishes. A larger difference was observed in the composition of species between the littoral and limnetic zones, with the species Jenynsia multidentata, Bryconamericus iheringii, Hyphessobrycon luetkenii and Gymnogeophagus gymnogenys dominating exclusively in the littoral, and the species Oligosarcus jenynsii, Cyphocharax voga, Odontesthes perugiae and Astyanax fasciatus dominating exclusively the near shore limnetic zone. The littoral zone presented differences in the composition and dominance of the species among the portions north and south of the lake. The 52 species registered in this study represent a high diversity of fishes in Mangueira lake, specially when compared to other coastal lakes of RS. Differentiated patterns of composition and abundance of species seem to reflect characteristics different from the coastal habitats sampled.


Este estudo apresenta a composição de espécies, os padrões de distribuição e dominância, e a estrutura de tamanhos da assembleia de peixes em diferentes unidades de hábitat (zonas litoral, profunda e limnética costeira) da lagoa Mangueira, no extremo sul do Brasil. As amostras foram obtidas no norte, centro e sul da lagoa, entre os anos de 2001 e 2007 utilizando-se de diversos amostradores (rede de emalhe, tarrafa, rede de arrasto de praia, puçá e rede de arrasto de fundo). Um total de 52 espécies foi identificado, 46 na zona litoral, 33 na limnética costeira e 26 na profunda, distribuídas em 17 famílias, das quais, Characidae, Cichlidae, Loricariidae e Atherinopsidae foram as mais diversas. As espécies dominantes somaram 91,1 %, 92,9 % e 82,7 % dos indivíduos capturados nas zonas litoral, profunda e limnética costeira respectivamente. A zona litoral é constituída de pequenos peixes, quase 70 % entre 25 e 50 mm de comprimento. Os padrões de dominância mostraram que, nesta zona, 19,5 % das espécies foram dominantes, embora quatro dessas também predominaram nas demais zonas. Na zona profunda, 7,6 % das espécies capturadas foram dominantes, com tamanhos semelhantes aos da zona litoral. Para as demais espécies, os tamanhos se assemelham aos da zona limnética costeira. A zona limnética costeira é constituída de peixes de maior porte, a maioria entre 150 e 200 mm de comprimento total, tais como os grandes caracídeos, o birú e os peixes-rei. Observou-se uma maior diferença na composição de espécies entre as zonas litoral e limnética costeira, com as espécies Jenynsia multidentata, Bryconamericus iheringii, Hyphessobrycon luetkenii e Gymnogeophagus gymnogenys dominando exclusivamente no litoral, e as espécies Oligosarcus jenynsii, Cyphocharax voga, Odontesthes perugiae e Astyanax fasciatus dominando exclusivamente a zona limnética costeira. A zona litoral apresentou diferenças na composição e dominância das espécies entre as porções norte e sul da lagoa. As 52 espécies registradas neste estudo representam uma alta riqueza de peixes na lagoa Mangueira, sobretudo quando comparada a outras lagoas costeiras do RS. Padrões diferenciados de composição e abundância de espécies parecem refletir características distintas dos habitats litorâneos amostrados.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA