Collins et a I.: Reproductive patterns, sex ratio, and fecundity of Mycteroperca microlepis 
425 
quency, and annual fecundity). Varying amounts 
of “missing” hydrated oocytes due to partial 
spawning would have then caused the low r 2 s. 
An incomplete hydration process in some of the 
gag is another possible explanation for the low 
r 2 values; samples were taken from gag caught 
at different times of the day, causing variable 
hydration (Hunter et al., 1985). Relatively low 
r 2 values for the relation between batch fecun- 
dity and length and weight were also found for 
black drum (r 2 <0.47, in Nieland and Wilson, 
1993) and swordfish, Ziphias gladius (r 2 <0.41, 
in Taylor and Murphy, 1992). Because dockside 
sampling was also used in these studies, de- 
layed preservation may have caused some black 
drum and swordfish POFs to be missed, thereby 
causing low r 2 values. 
In this study, we used histological sections to 
identify sex in gag with heavy abdominal pig- 
mentation. Because male behaviors are associ- 
ated with fish demonstrating this pigment pat- 
tern (Gilmore and Jones, 1992), the assump- 
tion is widespread that all these fish are males. 
Yet we found that 5% of such pigmented fish 
were females. It is possible that these fish were 
actually in the early stages of sex change, a 
phase undetectable even with histology. 
Our observation of a lining of hydrated oo- 
cytes around the outside of the abdominal cav- 
ity in gag suggests that the ovary or the ovi- 
duct, or both, had ruptured at the time of hy- 
dration. This rupture probably did not occur 
during the fish’s capture and handling because 
the lining of hydrated oocytes was dry and firm 
when we observed this phenomenon on the boat. 
A similar rupture may have occurred in a cap- 
tive population of laboratory-matured female 
gag where two individuals spontaneously de- 
veloped hydrated oocytes but did not ovulate; 
no oocytes were shed although no ovarian rup- 
ture was noted, possibly due to the absence of a 
male. 4 Although the proportion of males re- 
quired for adequate fertilization is unknown for 
gag, the sharp decline of males observed by 
Coleman et al. (1996), Koenig et al. (1996), 
McGovern et al. (in press), and in this study 
suggests a restricted availability of males dur- 
ing the spawning period. Ovarian hydration in 
females in the absence of males could lead to 
ovarian rupture. 
Although recent studies have increased our knowl- 
edge of gag reproduction, several significant ques- 
LU 
Li. 40 
cn 
* 
¥ 
3 4 5 6 7 
Age (years) 
1991 ▼ 1993 * 1994 
Figure 6 
Gag spawning frequency estimates (SFE) by age and year, for 
ages with n > 5 by year. 
4 Carr, W. 1992. Whitney Laboratory, University of Florida, 
St. Augustine, FL. Personal commun. 
tions remain. Gag appear to spawn at a discrete 
depth; therefore should only those females from a 
known spawning area be used for spawning fre- 
quency and fecundity estimates? Do fewer males in 
proportion to females prevent some mature female 
gag from spawning every year (Coleman et al., 1996; 
