600 
Fishery Bulletin 95(3), 1997 
1995) or showed atresia of vitellogenic oocytes. Males P x = l/( l+e ax+b ), 
whose testes contained either spermatids or sper- 
matogonia were classified as mature. The proportion where P x is the proportion mature at a given length 
mature at each length was calculated by 
x, and a and b are constants. Size at fifty percent 
Table 1 
Macroscopic and histological descriptions of developmental stages used to classify male and female arrowtooth flounder, Atheresthes 
stomias (adapted from Rickey, 1995). Mean oocyte diameter in parentheses. 
Macroscopic stage and description 
Histological stage and description 
Females 
A Immature Ovaries small and pink 
with no oocytes visible. 
1 Oogonia Very small (2.5 p) and staining dark purple. 
2 Chromatin nucleolus Nucleus large, one nucleolus, cytoplasm layer 
thin, both staining dark purple (25-75 p). 
3 Early perinucleus Nuclear material granular, several nucleoli around 
perimeter of dark-purple-staining nucleus, lighter purple vacuoles (cortical 
alveoli) forming around nucleus and moving outward in dark-purple-staining 
cytoplasm. Cytoplasm growing in thickness (37.5-75 p). 
4 Late perinucleus Material in nucleus often moving to one side leaving 
much of nucleus clear, becoming fibrous with lampbrush chromosomes. Many 
nucleoli evenly spaced around perimeter of nucleus, cytoplasm staining less 
purple, ring of light purple vacuoles (cortical alveoli) still moving outward, 
sometimes dividing cytoplasm into two zones (150-162.5 p). 
B Developing Ovaries white to yellow, 
firm, oocytes visible. 
5 Cortical alveoli Some lampbrush chromosomes still present, but 
nuclear material dispersing and nucleus turning light purple, collapsing 
inward. Vacuoles in cytoplasm (cortical alveoli) near cell wall, clear, one to 
three layers thick, cytoplasm much lighter purple (325-375 p). 
6 Early vitellogenesis Nucleus light purple to pink in color, collapsing 
inward. Cortical alveoli increasing in diameter, on the outer margin of the cell 
wall. First yolk globules (pink) in cytoplasm, generally closer to the center of 
the oocyte than the cortical alveoli, sometimes in spokelike configuration. 
Cytoplasm less than 50% filled with yolk (375-425 p). Yolk globules 7.5 p. 
7 Late vitellogenesis Pink-staining yolk globules occupy 50-100% of 
the cytoplasm. Oocyte diameter 500 p and yolk globules expanding to 12.5 p. 
8 Migratory nucleus Yolk globules coalescing and increasing in 
diameter (25-37.5 p), nucleus sometimes visible as a crescent shape, cortical 
alveoli no longer visible near edge of cytoplasm, oocyte large (625-725 p). 
C Gravid Hydrated oocytes present. 
9 Hydrated Nucleus no longer visible, yolk coalescing and filling 
cytoplasm as continuous material. 
D Ripe and running Oocytes ex- 
truded with light pressure. 
10 Spawning Postovulatory follicles present. 
E Spent or resting Ovaries bloodshot, 
flaccid, and dark red to purple. 
11 Atretic Atresia of large, previously yolked oocytes, no stages beyond 
late perinucleus present. 
Males 
Immature Testes small and threadlike, 
pink. 
Spermatogonia, primary or secondary. Spermatocytes present. 
Mature Testes enlarged, folded, brown 
or white in color. 
Spermatids or spermatogonia present. 
