McGovern et al.: Changes in the sex ratio and size at maturity of Mycteroperca microlepis 
799 
Tabie 1 
Histological criteria used to determine reproductive state in gag, Mycteroperca microlepis (based on Moe, 1969; Hunter and 
Macewicz, 1985; Hunter al. 1986; Collins et al., 1987; West, 1990; Ferreira, 1993; Shapiro et al., 1993a, 1993b). 
Reproductive state 
Male 
Female 
Immature 
No primary males found. “Immature 
males” in Moe (1969) considered late 
transitional because sex transition is not 
yet completed. 
No evidence of atresia. In comparison to resting female, 
oogonia more abundant along the margin of lamellae, 
most previtellogenic oocytes <80 pm in diameter, area 
of transverse section of ovary is smaller, lamellae lack 
muscle and connective tissue bundles, lamellae are not 
as elongate, and ovarian wall is thinner. 
Developing 
Development of cysts containing primary 
and secondary spermatocytes through 
some accumulation of spermatozoa in 
lobular lumina and peripheral sinuses 
within gonadal wall. 
Oocytes undergoing cortical granule (alveoli) formation 
through nucleus migration and partial coalescence of 
yolk globules. 
Running ripe 
Predominance of spermatozoa in lobules 
and peripheral sinuses. Little or no 
occurrence of spermatogenesis. 
Completion of yolk coalescence and hydration in the 
most advanced oocytes. Zona radiata becomes thin. 
Postovulatory follicles sometimes present. 
Spent 
No spermatogenesis. Some residual sperma- 
tozoa in lobules and peripheral sinuses. 
More than 50% of vitellogenic oocytes in alpha or beta 
stage of atresia. 
Resting 
Little or no spermatocyte development. 
Empty lobules and sinuses evident. 
Traces of atresia. In comparison to immature female, 
oogonia less abundant along margin of lamellae, most 
previtellogenic oocytes >80 pm in diameter, area of 
transverse section of ovary is larger, lamellae have 
muscle and connective tissue bundles, lamellae are more 
elongate and convoluted, and ovarian wall is thicker. 
Developing, 
recent spawn 
Not assessed. 
Developing stage as described above plus presence of 
postovulatory follicles. 
Mature specimen, 
state unknown 
Mature, but inadequate quantity of tissue 
or postmortem histolysis prevent further 
assessment of reproductive state. 
Mature, but inadequate quantity of tissue or postmor- 
tem histolysis prevents further assessment of reproduc- 
tive state. 
Transitional 
Proliferation of spermatogonia through limited spermatogenesis within lamellae of resting ovary and development of peripheral 
sinuses in musculature of ovarian wall. 
be compared. The sex ratio for 1995 was based on 
mature individuals that were collected during the 
early portion of the emergency rule (18 January to 
18 April 1995). Recent data were analyzed by region: 
North Carolina, South Carolina, Georgia, northern 
Florida, and southern Florida (south of New Smyrna 
Beach). Plots of reproductive seasonality were based 
on all individuals that were collected during 1994 
and 1995. Females that possessed hydrated oocytes 
or postovulatory follicles were considered to be in 
spawning condition. 
Data for all females collected during the two peri- 
ods were used in size-at-maturity analyses. The 
probit procedure (SAS, 1990) was used to fit a gompit 
model with the Gompertz distribution function to 
maturity data in 5-cm-TL intervals. This procedure 
provided estimates of length at 50% maturity (L 50 ) 
and a comparison of size at maturity between peri- 
ods. Analysis of variance (AN OVA) and the Duncan 
multiple range test were used to determine if there 
was a significant difference in the mean size of gag 
collected by month for mature individuals. AN OVA 
and the Duncan multiple range test were also used 
to determine if there was a significant difference in 
the monthly mean size of gag between 889 and 1050 
mm TL to reduce the potential for bias that might 
result from selection of larger fishes during the lat- 
ter part of the emergency rule. The results of all sta- 
tistical tests were considered significant if P was 
<0.05. 
