Figure 1

Oocyte stages. Micrographs of various oocyte stages considered for European hake (Merluccius merluccius), ranging from previtellogenic oocytes (PVO1-4c) via cortical alveoli oocytes (CAO) to early (EVO) and medium-late vitellogenic oocytes (VTO). PVOs are classified as belonging to primary oocytes, while CAO, EVO and VTO are secondary oocytes. The shape of the illustration mimics the increasing numerical reduction with oocyte stage.