424 
Fishery Bulletin 108(4) 
differed among species (Fig. 3) and the oldest fish was 
a 36-year-old S. nematophorus. 
Regional and sex-specific differences in length- and 
age-frequency distributions could only be analyzed for 
L. carponotatus because of low sample sizes for all 
other species. There was a significant effect of sex on 
lengths (Kolmogorov-Smirnov test: n 1 =1279, n 2 = 399, 
d max = 0 - 336 , D = 0.078, P<0.05) and ages (n 1 = 1279, 
n 2 - 399, c? max =0.281, .0=0.078, P<0.05) for the frequency 
distributions and a greater proportion of males than fe- 
males in the larger size classes and younger age classes 
(Fig. 4). Differences in growth by sex were significantly 
different (^ 2 = 68.34, PcO.OOOl), with males reaching 
a significantly greater maximum size than females 
(female: L^- 278, ,K=0.43, t 0 =-2.55; male: 0^=293, 
K= 0.55, f 0 =-1.43). 
The unconstrained fits of the VBGF differed substan- 
tially among species with L. carponotatus, A. virescens, 
and L. fulviflamma reaching a maximum size relatively 
early in life (Fig. 5). Symphorus nematophorus reached 
a maximum size somewhat later in life, and the growth 
curve for L. gibbus was not asymptotic. The lack of 
juvenile fish collected for all species, but particularly 
for L. carponotatus, L. fulviflamma, and L. gibbus, re- 
sulted in relatively flat fits of the unconstrained VBGF. 
The nonasymptotic growth pattern for L. gibbus indi- 
cates that under-sampling of larger individuals may 
also have occurred. VBGF parameter estimates for all 
species from the unconstrained 
fit are likely to be biased and 
should be interpreted with some 
caution. 
Constraining the VBGF by 
setting t 0 =0 produced similar 
estimates of K and L x to those 
for the unconstrained estimates 
for L. carponotatus and L. ful- 
viflamma. Despite limited sam- 
pling of the youngest individu- 
als, this similarity indicates 
that a sufficiently wide range 
of age classes were sampled in 
these populations to produce bi- 
ologically reasonable estimates 
of growth without the need to 
constrain t Q . Constraining t 0 re- 
sulted in faster initial growth 
estimates (greater estimate 
of K) and smaller asymptotic 
length (LJ than the uncon- 
strained fits for S. nematopho- 
rus, A. virescens, and L. gibbus. 
The constrained fit produced a 
more asymptotic growth curve 
for L. gibbus, indicating that 
constraining t 0 may have pro- 
vided a more biologically realis- 
tic estimate of length-at-age for 
this species. 
Both constrained and uncon- 
strained growth curves differed 
across species. These species 
showed distinct differences in 
the rate of growth at young 
ages and the age at which 
they reached average maxi- 
mum length: smaller species 
grew fast in the first couple of 
years and reached asymptotic 
length early, whereas larger 
species grew slightly slower in 
the first few years to reach an 
asymptotic FL later. The lack of 
small-size individuals resulted 
S. nematophorus 
o= 168 
i£U 
ri n~HT-n 
,[_ix i 
□ , n n n 
■(NICMCMCNCNIfOfOfOCO 
ill 
L gibbus 
a=166 
10 
L fulviflamma 
o=55 
IQ 
Age 
Figure 3 
Age-frequency distributions for five lutjanid species on the Great Barrier Reef 
between 1995 and 2005 (note difference in y axes). 
