Appendix 1 Description of oocyte developmental stages

Stage 1: Undifferentiated – where follicular structure is indistinct and there is no sex cell primordial.
Stage 2: Differentiated – where oocyte development commences, primary oogonia are visible, sex cell range from 15–25 μm in diameter.

Stage 3: Developing – where there are mostly pre-vitellogenic and vitellogenic oocytes, follicle lumen is open or only partially occluded and oocyte diameter ranges from 30–70 μm.
Stage 4: Ripe – where gonads show packed follicles, the follicular lumen is occluded, there is no inter-follicular space visible, and oocytes range 60–70 μm in diameter.
Stage 5: Spawning – where the follicle lumen is opening, follicle size diminishing and ripe oocytes range 60–70 μm.
Stage 6: Spent – where follicles are empty and frequently filled with haemocyte aggregations on slide preparations and an occasionally atretic oocyte is present.
Stage 2: Differentiated Stage 3: Developing
Stage 4: Ripe Stage 6: Spent