182 
Fishery Bulletin 112(2-3) 
Table 1 
Sample size (n), mean total length (TL, in millimeters) and minimum and maximum TL values by 
month and sex for Southern Kingfish (Menticirrhus americanus ) collected in Mississippi Sound, 
Mississippi, from April 2008 to May 2009. 
Female Male 
Date 
n 
Mean TL 
Min TL 
Max TL 
n 
Mean TL 
Min TL 
Max 1 
April 2008 
45 
232 
192 
267 
3 
234 
227 
244 
May 2008 
3 
270 
231 
303 
- 
- 
- 
- 
June 2008 
45 
217 
164 
312 
29 
193 
173 
224 
July 2008 
42 
243 
163 
348 
10 
226 
180 
256 
August 2008 
33 
254 
219 
331 
7 
231 
212 
267 
September 2008 
51 
252 
191 
328 
3 
233 
226 
242 
October 2008 
49 
238 
182 
341 
6 
222 
215 
240 
November 2008 
16 
258 
205 
307 
2 
212 
203 
220 
December 2008 
3 
266 
246 
278 
2 
233 
221 
244 
February 2009 
45 
239 
181 
283 
10 
217 
198 
263 
March 2009 
49 
229 
135 
279 
6 
210 
171 
244 
April 2009 
11 
246 
148 
280 
2 
199 
198 
200 
May 2009 
42 
232 
184 
300 
5 
207 
191 
224 
Overall 
434 
- 
135 
348 
85 
- 
171 
267 
ed with hook and line, 7 were collected in otter trawls, 
and 4 were collected from crab pots. All haphazardly 
sampled specimens were within the normal size dis- 
tribution (trawls, 187-300 mm TL; crab pots, 263-280 
mm TL). Sizes of females were recorded in ranges of 
135-348 mm TL and 24.8-530.2 g; males fell in size 
ranges of 171-267 mm TL and 49.4-213.4 g (Table 1; 
Fig. 2, A and B). There was a significant linear rela- 
tionship between TL and SL for both sexes (Table 2; 
males: P< 0 . 0001 , coefficient of multiple determination 
[i? 2 ]=0.98; females: P< 0 . 0001 , R 2 = 0.96). 
Comparison of the mean values and confidence inter- 
vals derived in the VBGF analysis indicated that males 
reach a significantly smaller asymptotic TL (a=0.05) 
and grow faster than females (Fig. 2, A and B; Table 
2). Females at all ages had a greater mean length than 
that of males (Fig. 20. The estimated longevity, cal- 
culated with the mean VBGF parameters, was 3. 1-4.3 
years for males and 3.6-5. 1 years for females (Table 
2). Significant differences in both a and b parameters 
were observed by comparing mean and 95% Cl values 
in the weight-at-length relationship (parameter a was 
the coefficient of the power function). Females had a 
significantly greater mean value of the power function 
exponent (parameter b) than had males: 3.26 versus 
2.88 (a=0.05; Table 2). 
Age determined from otoliths 
Alternating opaque and translucent annuli were dis- 
tinctive in the prepared cross sections of Southern 
Kingfish otoliths (Fig. 3A). Marginal increment analy- 
sis showed that Southern Kingfish in the GOM form 
opaque annuli during April and May, on the basis 
of the presence of fish with a margin code of 1 ( 0 % 
translucence above the opaque annulus; Fig. 3B). A 
single fish had a margin code of 1 in June, although 
2 was the dominant margin code in June and July 
(78% and 73% of fish, respectively). Fish with a mar- 
gin code of 2 showed active accretion of the otolith 
beyond the formation of the opaque annulus. Mar- 
gin codes 3 and 4 were most common from August to 
March; margin code 4 was dominant in February and 
March, just before the deposition of the opaque annu- 
lus (Fig. 3B). 
There were 5 age classes (age 0-4) observed in the 
sampled mature population (n=123) of Southern King- 
fish in the northcentral GOM. Fish of age 1 and 2 were 
the largest groups, accounting for 39% and 33% of the 
total, respectively. Because of the sampling technique 
used, young-of-the-year (age- 0 ) fish composed only 12 %, 
and fish of age 3 and 4 represented 13% and 3% of the 
sample, respectively. 
Reproductive characteristics 
Of the 519 Southern Kingfish collected, ovary samples 
from 397 females were processed for histological analy- 
sis. The smallest female observed to reach sexual ma- 
turity was 163 mm TL and age 1. Only 3.5% of the 
397 females histologically examined were found to be 
immature. Estimated size at L 50 was 171 mm TL (Fig. 
4; i? 2 =0.71, az= 396 ). All females >211 mm TL were sexu- 
ally mature and were age 1 or older. 
