Clardy et at: Life history of Menticirrhus amencanus and other sciaenids 
189 
Table 5 
Mean batch fecundity (number of eggs) and relative batch fecundity (number of eggs 
per gram of ovary-free body weight) by month and age class for Southern King- 
fish (Menticirrhus americanus) collected between April 2008 and May 2009 from the 
northcentral Gulf of Mexico (Mississippi Sound, Mississippi). Standard errors of the 
mean (SE) are provided in parentheses. 
Mean batch 
Mean relative 
Month or age 
n 
fecundity (SE) 
batch fecundity (SE) 
May 
2 
33,944 (2408) 
228.0 (25.1) 
July 
3 
35,150 (12,213) 
201.6 (18.9) 
August 
3 
38,722 (20,888) 
259.6 (124.9) 
September 
3 
33,924 (12,544) 
168.1 (70.3) 
Age 1 
4 
33,730 (15,591) 
235.7 (91.5) 
Age 2 
7 
36,622 (6122) 
200.2 (29.4) 
Overall 
11 
35,571 (6405) 
213.1 (35.7) 
estimated birth dates in late March (n= 5), the great- 
est frequencies occurred between June and August, 
and this period marks the plateau in GSI values and 
the highest percentages of actively spawning fish not- 
ed from histological analysis. This evidence indicates 
that the notion of 2 discrete spawning periods within 
the season does not apply to this population. Further- 
more, our data are in close agreement with recent his- 
tological analyses of Southern Kingfish from the SAB, 
where this species also has a single spawning period. 
McDowell and Robilland (2013) found spawning fish 
in Georgia estuaries from March to July, although 
spawning-capable females were seen also in August 
and September. 
Fecundity data provide information that will aid in 
Table 6 
Summary of loadings from principal components analy- 
sis (PCA) of the 5 somatic and reproductive variables 
onto the 2 most meaningful principal components (PC 
1 and PC 2). Loadings represent Pearson’s correlations 
of original metrics to each component. Only correlation 
values | >0.60 | (shown in bold) are considered useful for 
naming components (Hair et al., 1984). Maximum total 
length is presented in millimeters, duration of spawn- 
ing season is shown in months, relative batch fecundity 
is reported in number of eggs per gram of ovary-free 
body weight and age at maturity is presented in years; 
6=slope of length-weight power function. 
Variable 
PC 1 
PC 2 
Maximum total length 
0.853 
-0.210 
Spawning-season duration 
-0.297 
0.830 
Relative batch fecundity 
- 0.626 
-0.396 
Age at maturity 
0.861 
-0.252 
b 
0.023 
0.708 
the determination of the spawning potential of South- 
ern Kingfish at different lengths and ages; however, 
fecundity measurements are poorly understood for the 
Southern Kingfish across its range. Previously report- 
ed estimates for 20 females in the northcentral GOM 
(Fritzsche and Crowe 3 ) were a mean BF of 105,359 
eggs (range: 46,024-332,229 eggs) and a mean RBF of 
527 eggs g _1 OFBW, but these 2 estimates are based 
on all oocytes >300 pm. Our data show that vitello- 
genic oocytes between 300 and 350 pm do not undergo 
OM and, therefore, represent several potential batch- 
es. Batch fecundity estimates in our study were lower 
than those found by Fritzsche and Crowe 3 because only 
hydrated oocytes or those oocytes undergoing OM were 
used. Militelli et al. (2013) reported RBF estimates for 
8 Southern Kingfish from Argentina as 217 eggs g _1 
OFBW (SE 70) — a finding that is similar to our results 
of 231 eggs g _1 OFBW (SE 36) for fish in the north- 
central GOM. McDowell and Robillard (2013) did not 
directly report RBF data for Southern Kingfish from 
Georgia, but we calculated RBF to be 308.6 eggs g _1 
total weight (SE 27.6) on the basis of information in 
their manuscript. 
The lack of a significant relationship in our data be- 
tween BF or RBF and TL, OFBW, or age is unusual, 
but it may be linked to our small sample size and the 
potential for significant variation in fecundity among 
individuals within a protracted spawning season (Low- 
erre-Barbieri et al., 2009). McDowell and Robillard 
(2013) had a more robust sample size of 36 fish and 
found a significant relationship between batch fecundi- 
ty and both length and weight. Therefore, our fecundity 
estimates should be viewed with caution, despite their 
similarity to fecundity estimates of the Argentinean 
stock. Overall, Southern Kingfish exhibit some of the 
lowest reported RBF values for sciaenids (Appendix), a 
trait shared with the other members of group B in the 
PCA (see Fig. 7): Sand Seatrout, White Croaker, and 
Queenfish. 
