Heupel et al. : Demographic characteristics of exploited tropical lut|anids 
425 
in a lack of definition of early growth in the un- 
constrained curves when compared to constrained 
estimates. Both constrained and unconstrained 
growth curves for L. carponotatus and L. fulvi- 
flamma were relatively “square-shaped” (Choat and 
Robertson, 2002), revealing little growth over most 
of their life spans. Several species had K values 
>0.30/yr, indicating rapid growth to maximum size 
at a young age. 
Comparison of growth rate among 5-12 year 
olds revealed significant differences among species 
(F 4 2503=1543.8, PcO.OOOl). Post hoc tests indicated 
that each species had a unique growth rate. Exami- 
nation of age at 50% L x indicated some differences 
between constrained and unconstrained fits (Table 
1), but in all cases, 50% of asymptotic length was 
reached at relatively young ages compared with 
estimated longevity, and only L. gibbus took longer 
than 10% of expected longevity to reach 50% of 
asymptotic size (Table 1). 
Lutjanus carponotatus was the only species with 
a sample size sufficient for regional analysis of 
growth data. Likelihood ratio tests indicated that 
patterns of growth differed significantly between 
Lizard Island, Mackay, and Storm Cay regions 
(^ 2 = 68.34, P<0.001) but there were similar L x 
values among regions, and quite variable K val- 
ues (Table 1). The most notable difference was the 
greater (and lower K) in the Storm Cay region 
(Table 1). 
Total mortality (Z) estimates calculated from 
catch curves varied significantly among the five 
species examined (F 441 =5.61, P=0.001) (Fig. 6). 
Z was highest for L. gibbus and A. virescens and 
lowest for L. fulviflamma (Table 2). Mortality rates 
calculated by the Hoenig method resulted in more 
homogeneous estimates, of which highest rates were 
for L. gibbus and lowest for S. nematophorus. Mor- 
tality estimates calculated from catch curves were 
higher than those estimated by Hoenig’s method for 
all species except L. fulviflamma (Table 2). Z for L. 
carponotatus did not vary significantly among the three 
regions (P 2 2 9 = 2.24, P=0.15) and therefore a single catch 
curve was fitted to data pooled across regions. 
All except one of the individuals sampled (282-mm 
L. gibbus ) were sexually mature, making analysis of 
size and age at maturity impossible. Adult sex ratios 
in a few of the sampled populations differed from a 1:1 
sex ratio (Table 3), despite the expected gonochoristic 
nature of these species. Sex ratios of L. carponotatus, 
L. gibbus, and L. vitta were biased significantly toward 
males. 
Discussion 
Many coral reef fish species have overlapping spatial 
distributions, are found in similar habitats, and grow to 
roughly similar sizes. It might be expected that superfi- 
cially similar species from the same family would have 
similar demographic characteristics and life history 
strategies. The results of this case study of lutjanid 
species, however, indicate that it is impossible to make 
generalizations about the life histories of members of a 
family, even where they grow to similar sizes and coexist 
in the same habitats. Even this small subset of seven 
lutjanid species had quite different growth, mortality, 
and longevity characteristics. Our results support pre- 
vious findings for individual species but also provide 
evidence of the considerable differences among species 
in this family and highlight the need for careful, and 
potentially species-specific, approaches to managing the 
harvest of lutjanid assemblages. 
Demographic characteristics of the lutjanid species 
described here must be considered in the context of 
the limitations of size selectivity of the fishing gear 
used to sample populations. No individuals below 200 
mm FL were collected for any species, meaning the 
youngest age classes were not fully selected, resulting 
