Oocyte development of Metapenaeopsis dalei (Penaeidae, Decapoda, Crustacea)

Summary

Oocyte development in the small penaeid shrimp Metapenaeopsis dalei was studied histologically. Seven stages were distinguished, namely (1) oocytes 10μm in diameter are strongly basophilic and spherical, (2) weakly basophilic ooplasm appears around the germinal vesicle, (3) follicle cells appear, (4) lipid globules appear in the ooplasm, (5) yolk granules start to appear in the ooplasm, (6) the germinal vesicle shrinks and migrates marginally, (7) the follicle cells disappear. This is the first report of a fully matured penaeid oocyte without cortical crypts which release materials forming a jelly coat when the eggs are exposed to seawater. Since ovulated oocytes occur in the same section of the ovary as earlier stages, M. dalei is concluded to be a multiple spawner which has short spawning intervals.

Key words:

• Oocyte development
• Metapenaeopsis dalei
• penaeid shrimp
• cortical crypt
• multiple spawning