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Fishery Bulletin 108(4) 
represented in the sample, resulting in overestimates 
of Z from catch curves. Estimates of Z derived from 
Hoenig’s equation may be more appropriate for these 
species. Similarly, older individual L. gibbus and L. 
fulviflamma may not have been collected by the gear 
and if so, under-sampling may have resulted in overes- 
timates of Z from the catch curves and Hoenig’s method. 
Notwithstanding these potential biases, comparison 
of mortality rates revealed that A. virescens had a 
similar mortality rate to that of L. gibbus, indicating 
that A. virescens also has a relatively high population 
turnover rate. Aprion virescens grows quickly to a large 
size but may not live as long as other lutjanid species, 
despite attaining relatively large sizes. Symphorus 
nematophorus, for example, attained the largest size 
and had the second lowest mortality rate of the species 
examined. Lutjanus fulviflamma mortality estimates 
differed most between estimation methods, with catch 
curve estimates resulting in lowest mortality rates for 
this species (0.14/yr), but the Hoenig estimate revealed 
higher mortality rates (0.25/yr), similar to those for 
A. virescens and L. gibbus. The Hoenig estimate was 
also similar to rates previously reported for L. fulvi- 
flamma (0.29/yr, Grandcourt et ah, 2006), indicating 
some bias in the estimate from catch curves. Like L. 
gibbus, L. carponotatus under six years of age could 
not be used in catch curve estimates of mortality, but 
the 6-23 year age classes yielded mortality estimates 
for L. carponotatus of 0.30/yr (catch curve) and 0.18/yr 
(Hoenig), similar to estimates calculated previously for 
this species (0.20/yr, Newman et al., 2000a; 0.26-0.29/ 
yr, Kritzer, 2004). The range of mortality estimates for 
the species examined in this analysis agree well with 
those for other lutjanids (Newman et ah, 1996, 2000a; 
Amezcua et al., 2006) and are another indication of the 
variability in life history strategies within the family. 
Maturity and sex ratio 
All except one individual sampled across all species 
were sexually mature, supporting the conclusion that 
these lutjanids reach sexual maturity early in life. 
Biased sex ratios were observed for all of the species 
sampled although the apparent biases were statistically 
significant for only three species. Two species (L. fulvi- 
flamma, A. virescens ) showed large but nonsignificant 
female-biased sex ratios, whereas all others showed a 
male-biased ratio, and three (L. carponotatus, L. vitta, 
L. gibbus) were not significantly different from 1:1. 
Lutjanids are gonochoristic species and therefore it 
may be expected that adult sex ratios would be close 
to 1:1 in local populations, although at least three 
other studies have revealed biased sex ratios. Kritzer 
(2004) found that L. carponotatus had a female-biased 
sex ratio, whereas Newman et al. (2000a) reported a 
strongly male-biased sex ratio for the same species in 
similar locations to those that we examined. Studies of 
L. fulviflamma from different locations showed widely 
variable sex ratios. Kaunda-Arara and Ntiba (1997) 
reported a male-biased sex ratio in Kenya, and Grand- 
court et al. (2006) reported a female-biased sex ratio in 
the southern Arabian Gulf. It is difficult, therefore, to 
establish generic patterns of sex ratios across, or even 
within, lutjanid species given the contradictory patterns 
in the literature and among the species sampled here. It 
is possible that sex-ratio bias is a result of a differential 
survival of males and females or sex-specific patterns 
in distribution that would result in males and females 
having different probabilities of capture in the sampling 
strategies used in various studies, including the present 
one. Kritzer (2004) was one of the few to have examined 
mortality by sex, but no difference in mortality by sex 
was found. This single result may indicate that differ- 
ential spatial distributions may be a more likely cause 
of sex-ratio biases in samples of lutjanid populations. 
It has been suggested that sex ratio may be more even 
during spawning events (Kritzer, 2004), but no data are 
available to test this hypothesis. 
Implications for management of lutjanid populations 
An improved understanding of the demographic param- 
eters of gonochoristic species is crucial to furthering 
research on the effects of fishing on their populations. 
Results here clearly demonstrate that all or even super- 
ficially similar (e.g., in size) subsets of lutjanid species 
should not be treated in the same manner in these types 
of analyses and that vulnerability is likely to be variable 
within the family. Careful consideration of the inherent 
life history variability of these species is required in the 
development of theories and generalizations about this 
family and others. 
This case study of seven lutjanid species clearly in- 
dicates that data from one species cannot be applied 
to another in determining appropriate management 
measures for these populations. Some species appeared 
to be more susceptible than others to overexploitation 
by fisheries because of their longer life spans and lower 
rates of mortality. Symphoi'us nematophorus is a good 
example of a species with a long life span, large size, 
and low mortality. The combination of these factors 
could make this species a desirable fisheries target 
(owing to its larger size than other lutjanids), but also 
one of the most vulnerable because of its life history 
characteristics. Symphorus nematophorus and L. gibbus 
are currently no-take species within the GBR and have 
historically been avoided because of a potential risk of 
ciguatera (a form of food poisoning from eating large 
reef fish), and therefore these species are largely pro- 
tected from harvest within this region, although this 
may not be the case in other parts of their range. 
In comparison, the longevity of L. carponotatus and 
L. adetii in relation to other lutjanid species may make 
them more vulnerable to overfishing than sibling spe- 
cies (Newman et al., 1996). Despite their small size and 
fast growth, these populations may be more vulnerable 
than similar species such as L. vitta which have shorter 
longevities and hence potentially faster population turn- 
over rates (Newman et al., 2000a). Notably, most of the 
species examined here recruited to the fishing gear at 
