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Fig. 1. Germ cell features (A,C,E) and panoramic views of ovaries (B,D,F). (A)
Small aggregation of oogonia. Note the large, pale nucleus, single nucleoli
and scarce cytoplasm. Scale bar, 10 µm. (B) Ovary in the resting stage from
a fish captured in July. Previtellogenic oocytes show a very basophilic
cytoplasm and various perinuclear nucleoli. It is possible to observe oocytes
in different sizes, some may be in very early stages of vitellogenesis. Scale
bar, 50 µm. (C) Oocyte in lipid yolk stage. Note the lipid droplets, the
numerous perinuclear nucleoli and the chorion. Scale bar, 50 µm. (D) Ovary
in the recovering stage from a fish captured in October. Oocytes are mainly
previtellogenic and lipid yolk. Scale bar, 100 µm. (E) Two oocytes in the
protein yolk stage. The protein yolk has pushed the lipid droplets to the
periphery. The chorions are wide. Note the follicular cells between the
oocytes. Scale bar, 50 µm. (F) Mature ovary from a fish captured in
December. It is possible to observe oocytes in all stages of development.
Fully grown oocytes, others in process of protein yolk deposition, lipid yolk
oocytes and previtellogenic oocytes. Scale bar, 100 µm.. The maturing
ovary, present in October and November is not shown. (G) Cell-type
distribution represented by relative area of four different types of oocytes
in ovaries of freshly captured females in June (N=4, non-breeding
season), October (N=4), and December (N=4, breeding season).
White, previtellogenic oocytes; cross-hatched pattern, lipid yolk oocytes;
hatched pattern, protein yolk oocytes; black, fully grown oocytes.
Previtellogenic oocytes are present throughout the year. ch, chorion; fg,
fully grown oocyte; fc, follicular cells; l, lipid yolk; lo, lipid yolk
oocyte; n, nucleolus; og, oogonia; p, protein yolk; po, protein yolk oocyte;
pv, previtellogenic oocyte.
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