Stephen et al.: Comparison of life history parameters for landed and discarded fish off the southeastern United States 
297 
for all ages (F values from 26.8 to 497.4, all P values 
were <0.001, df=l; Fig. 3C). 
Sex and maturity status were assigned to 943 
scamp (821 females and 122 males). Sex ratios of 
legal- and sublegal-size fish were significantly dif- 
ferent from 1:1 (legal-size fish: ^ 2 = 68.5, P<0.001, 
df=l; sublegal-size fish: ^ 2 = 525.1, P<0.001, df= 1). 
There were low numbers of males captured, and sex 
ratios favord females for both legal- and sublegal-size 
scamp (legal-size fish 1:2.40 and sublegal-size fish 
1:134.25). Immature scamp were between two and 
six years old (Table 3) and 307 to 473 mm FL (Table 
4). Because a limited number of immature legal fe- 
males were collected (n= 2), probability of maturity at 
size and age were calculated by using both legal- and 
sublegal-size fish. Length and age at 50% maturity 
were estimated at 331 mm FL and two years, and 
length and age at 100% maturation were estimated 
at 474 mm FL and seven years, respectively. Sexual 
transition occurred over a wide range of ages and 
lengths (3-13 years; 440-720 mm FL; n= 26) and 
consisted entirely of adult fish. Probabilities of sexual 
transition were calculated from the entire data set 
because of the low number of sublegal-size males. 
Length at 50% and 100% sexual transition were 629 
mm FL and 740 mm FL, respectively, whereas age 
at 50% sexual transition was 9.7 years and at 100% 
sexual transition, 14 years. 
Discussion 
Vermilion snapper 
Vermilion snapper were reported in the South East 
Data, Assessment, and Review (SEDAR) 2008 stock 
assessment as experiencing overfishing, but were not 
overfished, with an F of 0.49 (SEDAR, 2008). This 
species has been managed with a 12 inch TL (274 
mm FL) commercial minimum size limit since 1999. 
Despite the minimum size limit regulation, F has 
continued to increase (SEDAR, 2008). The compari- 
son of the life history parameters of commercially 
caught legal- and sublegal-size vermilion snapper 
show that commercial fishing crews are capturing 
young, but large vermilion snapper — a fast growing 
phenotype. Comparing growth curves to previous 
time periods (1979-81 and 1985-93, Zhao et al., 1997), 
we found an increased growth rate for the current time 
period, particulary for the young fish (<5 yr), although 
asymptotic length, L m , values are similar to those found 
from 1979 to 1981 (Fig. 4A). This increased growth rate 
allows fish to reach the minimum size limit at an earlier 
age. Interestingly, the for this study is only 25 mm 
greater than the minimum size limit. 
Size at maturity is not a good indicator of differen- 
tial fishing pressure on fast growing phenotypes for 
vermilion snapper because all immature fish in the 
collections were female and sublegal. This is not an 
unexpected result because vermilion snapper mature at 
400 
350 
300 
250 - 
200 
150 
100 -*-r 
A (vermilion snapper) 
* 5 5 5 
5 5 
o o re n 2 
10 
12 
450 
400 
350 
0J 
O 300 
250 
200 
900 
800 
700 
600 - 
500 
400 
B (red porgy) 
* I 
I 
2 
2 I 
2 
0 2 
6 8 10 12 14 16 
300 
C (scamp) 
5 5 
il 
I 
6 8 10 12 
Age (years) 
14 
16 
Figure 3 
Mean fork length at age (±2 standard errors) for sublegal- 
(white) and legal-size (black) fish by species: (A) Rhombo- 
plites aurorubens (vermilion snapper), (B) Pagrus pagrus 
(red porgy), and (C) Mycteroperca phenax (scamp). 
a very small size and age. In a study on the reproduc- 
tive biology of vermilion snapper, Cuellar et al. (1996) 
found no immature fish (n = 1004, size range=165-375 
mm FL). Comparison with other studies (Zhao and 
McGovern, 1997), shows that vermilion size and age at 
maturity has decreased since the 1980s, a period when 
maximum length decreased. 
The observed sex ratios in our study favored males, 
in contrast to either 1:1 ratios or more females from 
other studies (Zhao and McGovern, 1997; Hood and 
Johnson, 1999; Allman, 2007; SEDAR, 2008). These 
differences may be attributed to location and gear se- 
lectivity. Hood and Johnson (1999) noted that the ver- 
