التفاصيل البيبلوغرافية
| العنوان: |
The reproductive biology of Plagioscion squamosissimus ( Heckel, 1840) in the Pará River estuary ( Amazon Estuary). |
| المؤلفون: |
Barbosa, N. D.1, Rocha, R. M.2, Lucena Frédou, F.3 |
| المصدر: |
Journal of Applied Ichthyology. Oct2012, Vol. 28 Issue 5, p800-805. 6p. 2 Black and White Photographs, 3 Charts, 4 Graphs. |
| مصطلحات موضوعية: |
*SCIAENIDAE, *ESTUARIES, *SEX ratio, *CHROMATIN, *REPRODUCTION |
| مصطلحات جغرافية: |
PARA River (Brazil), BRAZIL |
| مستخلص: |
This study describes the reproductive biology of the South American silver croaker Plagioscion squamosissimus ( Heckel, 1840) in the Pará River estuary. Data were collected bimonthly from June 2007 to May 2008. In all, 334 specimens were examined. The gonads were processed with histological techniques, and the ovaries were subjected to morphometric analysis. The length at first maturity (L50) values were 16.14 and 21.43 cm total length for females and males, respectively. The sex ratio based on the total number of individuals favoured the females (1.11 females: one male). Macroscopically, the gonads were classified as immature ( A), maturing ( B), mature ( C) and spent ( D). Microscopically, four germ cell types were distinguished based on the development of the ovaries. Chromatin nucleolus ( I), perinucleolar ( II), cortical alveoli ( III) and full-vitellogenic ( IV) oocytes were observed in all ovarian stages, except that of the mature individuals which showed the largest number of full-vitellogenic oocytes ( IV), with a mean diameter of 565.4 μm (±147.4). Substantial percentages of individual P. squamosissimus were found to be in a reproductive condition. Reproductive activity was recorded throughout the year in the Pará River estuary, primarily in February/ March and August/ September. [ABSTRACT FROM AUTHOR] |
| قاعدة البيانات: |
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