| Resumo: |
Reproduction of white croaker collected during 1991-1993 in the Argentine-Uruguayan Common Fishing Zone (CFZ)(34°-39°30'S), was studied by means of histological analysis of ovaries. Areal and seasonal maturity stage distributions were compared; ripeness degree was correlated to horizontal salinity gradients. During June and July an overall predominance of the resting stage was observed; nevertheless, a high proportion of females in early maturation was detected near Cabo San Antonio and Punta Piedras. In late October-early November an increase of maturing individuals was observed. Females in advanced maturity stage and partially spent,with postovulatory follicles, were collected mainly in estuarine waters with wide bottom salinity ranges (between 9-25 psu), in agreement with the saline front. This suggests that spawning areas of Micropogonias furnieri could be associated with this oceanographical feature. Late November showed a high proportion of females in partial spent stage, which indicates an increase in spawning activity. In early April a high percentage of individuals in reproductive activity was observed. Nevertheless, the increase of atretic oocytes suggested that the end of the spawning was imminent.
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