Reproduction of the lambariAstyanax scabripinnis(Jenyns, 1842) (Pisces: Characidae) in a small stream in Southeastern Brazil

Autor: José Enemir dos Santos, M. D. M. Barros, R. S. L. Barata, V. C. Veloso-Júnior, Rodrigo J. Guimarães-Cruz
Rok vydání: 2009
Předmět:
Zdroj: Journal of Applied Ichthyology. 25:314-320
ISSN: 1439-0426
0175-8659
DOI: 10.1111/j.1439-0426.2008.01152.x
Popis: Summary The reproduction of Astyanax scabripinnis captured bimonthly in the Cristais small stream (20 o 00¢03¢S and 43 o 56¢46¢W), in the Das Velhas River basin, was studied using gross anatomical and histological techniques. Standard length of females (56 ± 8 mm) was longer than males (49 ± 6 mm). The diameter of the nucleus of the primary spermatogonia was 7.5 ± 0.9 lm and of the spermatozoon head 1.8 ± 0.4 lm. For the females, the oogonia nuclei measured 10.2 ± 2.2 lm and the vitellogenic oocyte nuclei measured 675.0 ± 66.7 lm. The following stages of the reproductive cycle were established: developing, mature, partially spent ⁄ spawned and completely spent ⁄ spawned. Maximum number of males (61.3%) and females (58.2%) at the mature stage was observed during November ⁄ December. The gonadosomatic index of males and females was highest during the mature stage (2.4 ± 0.6; 7.5 ± 1.3, respectively) and decreased in subsequent stages. In females, the hepatosomatic index was highest during the developing stage (2.8 ± 0.3), and slightly decreased in the following stages. The highest stomach repletion index found for males was observed during the partially spent stage (2.0 ± 1.2), while for the females, this index varied discretely between the reproductive stages. The highest values of Fultons condition factor were registered during the mature stage in both sexes (2.9 ± 0.4 for males; 3.0 ± 0.3 for females). The continuous reproductive period and the presence of partially spawned females during the entire sampling period indicated that the species has fractional spawning.
Databáze: OpenAIRE
Externí odkaz: