Nutrition dynamics of "tambiú” Astyanax bimaculatus Linnaeus, 1758 (Pisces, Characiformes, Characidae) in Ibitinga Reservoir, São Paulo State, Brazil

Authors

  • Ricardo Amaro dos SANTOS Pesquisador Cientí­­fico- Seção de Controle e Orientação da Pesca -  Divisão de Pesca Interior -  Instituto de Pesca - CPA/SAA
  • Maria Teresa Duarte GIAMAS Pesquisador Cientifico - Seção de Biologia Aquática -  Divisão de Pesca Interior de Pesca -  CPA/SAA
  • Elmar Cardozo CAMPOS Pesquisador Cientí­­fico- Seção de Controle e Orientação da Pesca -  Divisão de Pesca Interior -  Instituto de Pesca -CPA/ SAA
  • Jaime José Casari da CAMARA Pesquisador Cientí­­fico- Seção de Controle e Orientação da Pesca -  Divisão de Pesca Interior -  Instituto de Pesca -CPA/SAA
  • Harry VERMULM JUNIOR Assistente Técnico Á  Pesquisa Cientí­­fica e Tecnológica - Seção de Controle e Orientação da Pesca -  Divisão de Interior Instituto de Pesca - CPA/SAA

Keywords:

Astyanax bimaculatus, , Ibitinga Reservoir, nutrition

Abstract

Respecting to Astyanax bimaculatus in Ibitinga Reservoir, seasonal variations of average index of stomach repletion (r), condition factor (Ñ"ž) and reIative frequency of repletion stages (fr) were analyzed. From July/1989 to June/1990, 704 individuals (379 females and 325 males) were examined. When males and females were considered together, relative frequency of demi-full stomachs remained around 50% during the year; the lowest frequency of full stomachs, which was close to the highest frequency of the empty ones, occurred in springs, and the highest, in autumn (in contrary progression relatively to that one observed for empty stomachs frequencies), when the condition factor has been maximum, after reaching its minimum in spring, what emphasizes the period of reproduction activity. When females were considered separately, full stomachs frequencies were higher in summer (maximum level) and autumn, and the minimum one occurred in spring, when demi-full stomachs frequency has been highest and both average index of stomach repletion and condition factor were lowest what evidentiated again the period of reproduction process

Published

2018-09-13

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