Stages of gonadal development and mean length at first maturity of wild Females of white shrimp (Litopenaeus schmitti – decapoda, penaeidae) in southern Brazil

Abstract

The stages of gonadal development for the female of white shrimp (Litopenaeus schmitti (Burkenroad, 1936)) were characterized based on histological analysis. Four stages (immature, developing, ripe and spawned) were determined according to the structure and arrangement of cells in the ovary. Each stage corresponds macroscopically to a characteristic color, except stages I (immature) and IV (spawned), in which colors are very similar and can be distinguished only microscopically. The chromatic scale varies from white/translucent (stage I), gray/green (developing), dark green to black (ripe). The mean size of cells was 54.01 μm (±3.5) (stage I), 136.80 μm (±8.8) (stage II) and 199.80 μm (±6.4) (stage III). The size frequency of cells was polymodal, and different cell stages were observed in ripe ovary, suggesting the occurrence of multiple spawning. The smallest ripe female measured 146 mm and the largest 180 mm of the total length. Estimated mean length at first maturity was 152 mm and the length at which 100% of females are mature is 170 mm.