Hyndes et al.: Age composition, growth, reproductive biology, and recruitment of Sillaginodes punctata 
263 
Age (years) 
Figure 3 
Von Bertalanffy growth curves fitted to total length-at-age data de- 
rived from sagittal otoliths of female and male Sillaginodes punctata. 
Although the vast majority of S. punctata 
caught by anglers in embayments and estu- 
aries at depths of 2-6 m were <370 mm in 
length and <4 years of age, those that were 
collected outside embayments and estuaries 
and in the vicinity of reefs at depths of 6-50 m 
were predominantly greater than this length 
and age (Fig. 8, A and B). Furthermore, S. 
punctata that contained mature (stages V- 
VII) or recovering or spent (stage VIII) go- 
nads were caught predominantly in and 
around reefs and at the edges of seagrass 
beds adjacent to these areas, where water 
depths exceeded 6 m (Fig. 8). 
Discussion 
Sexual maturity and spawning period 
Gonadal data indicate that, in southwestern 
Australia, female S. punctata reach matu- 
rity at the end of their fourth year of life or 
when they have attained a length of ca. 410 
mm. This length far exceeds the 350 mm at 
which 50% of the members of this species 
reach maturity in southeastern Australian 
waters (see Cockrum and Jones 2 ). However, 
the data of Cockrum and Jones 2 suggest that 
the length at maturity of S. punctata in 
southeastern Australia has declined since 
the 1950’s as a result of fishing pressure, a 
trend that has been observed with increased 
fishing pressure in other species of teleosts 
(Wootton, 1990). Such a conclusion would be 
consistent with the fact that in southwest- 
ern Australia, where S. punctata is not at 
present as heavily exploited, the length at 
maturity (ca. 410 mm) is similar to that re- 
corded in South Australia in the 1950’s 
(Scott, 1954; Cockrum and Jones 2 ). 
Because large numbers of yolk granule and 
hydrated oocytes and postovulatory follicles were first 
found in the ovaries of large female S. punctata in 
June and were prevalent in ovaries through Septem- 
ber, we conclude that this species spawns during this 
four-month period between early winter and early 
spring. Because the advanced oocytes present in ova- 
ries in October and November were usually under- 
going atresia, the spawning period of S. punctata 
rarely extends beyond September. The spawning of 
<S. punctata during winter to early spring in south- 
western Australia contrasts with the autumn and 
early winter spawning period found for S. punctata 
in southeastern Australia (Bruce, 1989; Jenkins and 
May, 1994; Fowler and Short, 1996; Cockrum and 
Jones 2 ). Thus, although the duration of the spawn- 
ing period of S. punctata is similar in both regions, it 
is initiated three months later on the lower west coast 
of Australia. It may thus be relevant that, in both 
regions, this species spawns when water tempera- 
tures are declining from their maxima and that this 
decline occurs more rapidly in southeastern Austra- 
lia than on the lower west coast of Australia (Fig. 1 
in Hyndes and Potter, 1996; Fowler 4 ). The above 
4 Fowler, A. 1995. SAUDI (South Australian Research and De- 
velopment Institute), PO Box 120, Henley Beach, Adelaide, 
South Australia 5022, Australia. 
