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Fishery Bulletin 109(1 ) 
Table 1 
Diagnostic microscopic criteria (after Pears et al., 2007) and key to classification of sexual identity, maturation, and reproductive 
status of female and male Hawaiian grouper ( Hyporthodus quernus), including gonadosomatic indices ( GSIs ) for each sex and 
diameter of the most advanced group of oocytes present in female ovaries. HYD=hydrated oocytes; POF=postovuiatory follicles; 
GifBVF=gonad-free body weight; OD=diameter of largest mode of viable oocytes; SE=standard error; n=sample size. 
Gonadal maturity 
Stage 
(0-10) 
Microscopic characteristics 
Mean ±SE (?i) 
GSI 
(as % of GFBW) 
Mean ±SE 
( n ) 
OD (pm) 
Mature? 
(yes/no) 
Immature bisexual 
0 
Vestigial gonad: sex indeterminate; 
primitive sex cells of either one or both 
sexes present 
0.08 ±0.009 (36) 
44 ±9 (3) 
no 
Immature female 
1 
Undeveloped ovary: only primordial 
(weakly nucleate) oocytes present 
0.08 ±0.007 (71) 
76 ±3 (28) 
no 
Developing female 
2 
Ovaries contain perinucleolar (cortical 
alveoli-stage) oocytes with nucleolated 
nuclei 
0.19 ±0.015 (85) 
110 ±4(22) 
no 
Ripening female 
3 
Oocytes largely previtellogenic; some 
eosin (pink) staining yolk vesicles 
0.54 ±0.079 (13) 
252 ±15 (13) 
yes 
Ripe female 
4 
Oocytes vitellogenic but not fully yolked; 
neither HYDs nor POFs present 
0.70 ±0.129 (12) 
313 ±13 (12) 
yes 
Imminent female 
5A 
Fully yolked oocytes; may have migratory 
nucleus; HYDs present 
1.41 ±0.061 (151) 
480 ±11 (29) 
yes 
Spawning female 
5B 
Fully yolked oocytes; POFs (or POFs and 
HYDs) present 
0.23 ±0.281 (34) 
533 ±12 (22) 
yes 
Resting female 
6 
Regressing or inactive, but previously 
spawned ovary: perinucleolar oocytes 
present; atretic oocytes, brown bodies, 
or both also present 
0.48 ±0.031 (138) 
111 ±6(23) 
yes 
Transitional male 
7 
Gonad contains inactive ovarian tissue; 
brown bodies usually present along with 
developing testicular tissue (Sertoli cells 
in sperm crypts) 
0.61 ±0.163 (5) 
yes 
Developing male 
8 
Recrudescing testes with spermatogonia; 
brown bodies may be present 
0.21 ±0.016 (22) 
— 
yes 
Active male 
9 
Ripe testes with spermatozoa in ducts or 
sinuses; brown bodies may still be present 
0.21 ±0.015 (31) 
— 
yes 
Resting male 
10 
Resting testes with evidence of prior 
spawning; sperm crypts present but no 
active spermatogenesis 
0.32 ±0.102 (2) 
yes 
(Table 1). All histological preparations were examined 
by a single experienced reader (DeMartini). 
Estimation of body sizes at maturation and at sex change 
Nonlinear regression with maximum likelihood esti- 
mation was used to relate fish body lengths to sexual 
maturity and to size at sex change (Proc nlin; SAS for 
Windows, vers. 9.1, SAS Inst., Inc., Cary, NC). Speci- 
mens were binned by 10-mm length classes; the propor- 
tions mature (female, male) were then related to length 
class by using the 2-parameter logistic model, 
( 1 ) 
where a and b are fitted constants; 
P x = percentage mature at x TL; and 
L 50 = (-alb). 
The proportions of mature and sex-changed fish were 
fitted by maximum likelihood by using Marquardt’s 
algorithm. Mean proportions per 10-mm length class 
were weighted by square root of the respective sample 
size. Estimates of size at sexual maturity were further 
compared between early and recent collection series 
by using likelihood ratio statistics (Quinn and Deriso, 
1999). A maximum likelihood chi-square test (Quinn 
and Keough, 2002) was used to compare adult sex ratios 
between collection series. 
P x = 100 / ( 1 + exp ta ~ b ' TL) ), 
