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Fishery Bulletin 95(4), 1997 
females because smaller individuals put more energy 
into somatic growth rather than into reproductive 
tissue (Rothschild, 1986). Zhao and McGovern 4 found 
that an apparent population size threshold at 30% 
of the virgin spawning biomass existed for vermilion 
snapper ( Rhomboplites aurorubens) in the SAB, be- 
low which recruitment failure was almost inevitable. 
A similar situation may exist for red porgy in the 
SAB, with recruitment failure exacerbated by the re- 
duction in size of mature females. 
Reproductive (i.e. recruitment) failure may also be 
affected by the change in size of male red porgy, as 
well as the changes in sex ratio that have occurred 
since 1972-74. Currently, some red porgy undergo 
transition at 200-250 mm FL. The sex ratio in 1991- 
94 at 352—400 mm FL was 1.3 males for each female. 
In 1972-74, the sex ratio for this size class was 0.06 
males per female (Manooch, 1976, macroscopic sex- 
ing). Males began to outnumber females only above 
451 mm FL. Koenig et al. (1996) have hypothesized 
that sperm limitation may be a factor in the decline 
of gag, Mycteroperca microlepis, in the northern Gulf 
of Mexico as the number of males in the population 
has declined. The size and number of male red porgy 
4 Zhao, B., and J. C. McGovern. 1995. Population character- 
istics of the vermilion snapper, Rhomboplites aurorubens , from 
the southeastern United States. Report to the South Atlantic 
Fishery Management Council, 1 South Park Circle, Charles- 
ton, SC 29422, 35 p. 
in the population have similarly been greatly re- 
duced. The reduction in size and number of males 
may also be a significant factor in the decline in the 
number of 1-year-old red porgy recruiting to the SAB 
population. 
Huntsman et al. 2 concluded that the red porgy 
population of the SAB was overfished and that the 
population was severely depressed. These conclusions 
were based on the results of Murphy and separable 
VPA’s that used only two age length keys — one from 
1972-74 and one from 1986 — and that used von 
Bertalanffy parameters and a length-weight relation 
from 1972-74. The life history of red porgy has changed 
markedly since 1986. In fact, as this study shows, sig- 
nificant decreases in size-at-age have occurred within 
a matter of years in this heavily fished population. The 
dramatic changes in the life history of red porgy and 
the resultant changes in parameters used for stock as- 
sessment suggest the status of the population in the 
SAB needs to be reassessed. 
Protogynous fishes may be particularly vulnerable 
to sustained heavy fishing pressure and size selec- 
tive mortality (Huntsman and Schaaf, 1994), particu- 
larly if sex reversal occurs primarily in response to 
exogenous controls (sociodemographic factors) (Koe- 
ning et al., 1996). The decline in size at sex transi- 
tion since 1979 suggests that the timing of transi- 
tion in red porgy is not determined by size, but rather 
by some social or behavioral stimulus. 
Red porgy probably do not ag- 
gregate to spawn; instead they ap- 
pear to be permanently schooled on 
the available areas of live bottom 
in the SAB. Koenig et. al. (1996) 
suggested that if a population of 
protogynous fish remained aggre- 
gated throughout the year, tran- 
sition could occur year-round and 
thus the normal male to female 
ratio could be maintained. If the 
numerical sex ratio is main- 
tained, the impact of overfishing 
on a protygynous species is re- 
duced (Huntsman and Schaaf, 
1994). The increase in the sex 
ratio seen from 1979-81 to 1988- 
90 may represent overcompensa- 
tion for the depletion of males 
from the population. The males 
of many reef-associated proto- 
gynous sparids show strong ter- 
ritoriality (van der Elst, 1988). If 
these males are more aggressive 
and are more likely to be caught 
by fishermen (Koenig et. al., 
