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Fishery Bulletin 95(3), 1997 
Figure 1 
Oocytes in arrowtooth flounder, Atheresthes stomias, at different stages of 
development. (A) Oocytes of a 57-cm-FL female at the cortical alveoli stage 
as well as less mature oocytes. (B) Oocyte of a 66-cm-FL female at the 
early vitellogenesis stage. (C) Oocytes of a 82- cm- FL female at the migra- 
tory nucleus stage. Bar = 0.1 mm; ON = oogonial nest; CN = chromatin 
nucleolus; EP = early perinucleus; LP = late perinucleus; CA = either cor- 
tical alveoli stage oocytes or cortical alveoli structures (with arrow); N = 
nucleus; Nu = nucleolus; YG = yolk globule. 
section, making them unavailable for 
the lobe-weight comparison. 
In the five-tier macroscopic staging 
scale for females (Table 1), fish were 
classified only as “immature” (stage A), 
“developing” (stage B), or “spent or rest- 
ing” (stage E). No females were found 
with hydrated oocytes (“gravid,” stage 
C) or that were “ripe and running” 
(stage D). The two-tier macroscopic 
maturity scale for males was abandoned 
early in the study because of lack of con- 
fidence in assigning stages — nearly all 
males appeared to be “immature.” 
Histological analysis revealed that all 
females were in stages 3-8 and stage 
11 of oocyte development (from early 
perinucleus to the migratory nucleus 
stage, and the atretic stage, Table 2). 
The lack of hydrated oocytes or post- 
ovulatory follicles in any of the ovaries 
indicated that these samples were col- 
lected prior to the spawning season. 
None of the males were ready to spawn 
but in some specimens, spermatids and 
spermatozoa were present, indicating 
that the males were preparing to spawn. 
Figure 1 shows photographs of histo- 
logical sections taken from females at 
three different stages of maturity. The 
progression of size increase of oocytes 
from the oogonial nest stage through the 
cortical alveoli stage can be seen in Fig- 
ure 1A. Some specimens in early vitel- 
logenesis, such as shown in Figure IB, 
had yolk globules arranged in a spoke- 
like configuration in the cytoplasm. The 
increase in oocyte size in the migratory 
nucleus stage, in comparison with oo- 
cyte size in the early perinucleus stage, 
and the increase in size of yolk globules 
are shown in Figure 1C. 
The categories of maturity stages, 
based on macroscopic examination, are 
shown in Table 2. Most of the females 
classified macroscopically as “imma- 
ture” (stage A, n= 76, length range 14- 
64 cm) were in the early or late peri- 
nucleus stage (n=6 2, 81.6%). A total of 
18.4% (14 of 76) of these females classi- 
fied macroscopically as “immature” were 
either in the process of maturing (corti- 
cal alveoli stage) or showed evidence that 
they had been mature the previous sea- 
son (atresia of previously yolked oocytes). 
