Hyndes et a I.: Age composition, growth, reproductive biology, and recruitment of Sillaginodes punctata 
261 
282 mm from November to January, and from 251 to 
403 mm from August to October, when this group of 
fish had just commenced their third year of life, and 
thus represents early 2+ fish (Fig. 2A). Between Au- 
gust and October, the lengths of 3+, 4+, and 5+ fish 
ranged from 340 to 425, from 403 to 480, and from 
431 to 495 mm, respectively. Sillaginodes punctata 
attained maximum ages of 14+ and lengths of 596 
mm in the case of females and maximum ages of 13+ 
and lengths of 555 mm with males. 
Growth curves derived for female and male S. 
punctata (Fig. 3) differed significantly (P<0.05). The 
asymptotic length (LJ and growth coefficient (K) for 
Table 1 
Von Bertalanffy growth parameters (+95% CL) derived 
from length at age data for Sillaginodes punctata caught 
on the lower west coast of Australia. L x is the asymptotic 
length, K is the growth coefficient, t 0 is the hypothetical 
age at which fish would have zero length, r 2 is the regres- 
sion coefficient, n is the sample size. 
von Bertalanffy parameters 
L„ K r 2 n 
Females 532.4+6.9 0.47 +0.02 0.13+0.02 0.97 760 
Males 500.1 +7.7 0.53+0.02 0.16+0.02 0.96 637 
females were 532 mm and 0.47, respectively, whereas 
for males they were 500 mm and 0.53, respectively 
(Table 1). 
Age and length at sexual maturity 
For determining the length and age at maturity of 
female S. punctata, the data for mature (stages V- 
VII ) and recovering or spent ( stage VIII ) ovaries were 
combined (Fig. 4). During the spawning period, which 
was determined as occurring from June to Septem- 
ber (see below), the proportion of female fish with 
mature and recovering or spent ovaries increased 
sharply from 4% in the 350-399 mm length class to 
71% in the 400-449 mm length class, and 100% in 
fish >500 mm (Fig. 4A). The length at which 50% of 
female S. punctata were mature, represented by the 
L 50 , was 413 mm. Maturity was first attained by fe- 
males at the end of their third year of life, when ca. 
15% offish possessed mature ovaries (Fig. 4B). How- 
ever, by the end of the fourth year of life, the propor- 
tion of mature females had increased markedly to 
72% and in subsequent years to 100%. A similar pat- 
tern was shown by the maturity stages for male fish 
(data not shown). 
Gonadal and oocyte development 
Because the vast majority ofS. punctata did not reach 
maturity until the end of their fourth year of life, the 
following monthly trends shown by gonadal stages 
were derived from fish that were >3.4 years old and 
thus these fish were expected to reach maturity in 
the following spawning period. Between January and 
May, the ovaries of all female S. punctata >3.4 years 
old were at either stages III or IV (Fig. 5). Mature 
ovaries were found in over 70% of females by June 
and in 90 and 100% by July and August, respectively. 
The proportion of mature ovaries declined markedly 
to 43% in September, whereas the contribution of 
