264 
Fishery Bulletin 96(2), 1998 
spawning periods for S. punctata contrast with those 
of the majority of other temperate marine teleost 
species, including other whiting species, which typi- 
cally breed at some period between late spring and 
early autumn (Morton, 1985; Vouglitois et al., 1987; 
Conover, 1992; Hyndes and Potter, 1996, 1997; 
Hyndes et al., 1996b). Because some of the estuaries 
of southwestern Australia often become closed from 
the sea by a sand bar in summer, a winter spawning 
period would allow the juveniles to become recruited 
into those estuaries (see “Nursery and spawning 
grounds” heading). 
The presence in some ovaries of S. punctata of large 
numbers of yolk granule oocytes, together with ei- 
ther hydrated oocytes or postovulatory follicles, sug- 
gests that this species releases its eggs in batches. 
Furthermore, the presence of hydrated oocytes or 
postovulatory follicles, or both, in many of those ova- 
ries which also contained advanced oocytes indicates 
that, although many oocytes were close to being re- 
leased from those ovaries, others had recently been 
discharged. There is thus strong circumstantial evi- 
dence that S. punctata spawns on more than one oc- 
casion and possibly frequently during each breeding 
period. The conclusion that S. punctata is a multiple 
spawner (sensu de Vlaming, 1983) supports the con- 
clusions of Cockrum and Jones 2 and parallels the 
situation recorded for several other sillaginid spe- 
cies (Morton, 1985; Hyndes and Potter, 1996, 1997; 
Hyndes et al., 1996b) and other teleosts in marine 
and estuarine waters in southwestern Australia (e.g. 
Hyndes et al., 1992b; Sarre et al., 1997). 
Age and growth 
The asymptotic lengths (L x ) and growth coefficients 
( K) of female and male S. punctata in southwestern 
Australia, i.e. 532 and 0.47, and 500 mm and 0.53, 
respectively, lie within the range calculated for 
this species in southeastern Australia. How- 
ever, these two parameters varied markedly 
in different localities within that latter region, 
i.e. 444 to 715 mm and 0.15 to 0.45 (Scott, 1954; 
Gilmour, 1969; Jones, 1980; Caton 1 ; Jones et 
al. 3 ). Such variation reflects either differences 
in the patterns of growth of this species in dif- 
ferent locations or errors associated with de- 
riving the age of fish from growth zones in 
scales or whole otoliths. 
Sillaginodes punctata reaches a far greater 
size and age than the five other sillaginid spe- 
cies in southwestern Australia, all of which be- 
long to the genus Sillago (Table 2). Further- 
more, <S. punctata does not attain maturity 
until it is four years old, which is far older than 
the age at which most of those Sillago species 
first spawn (Table 2). Because size and age at 
maturity are usually related to the length and 
age attained by teleosts (e.g. Beverton, 1992; 
Hyndes and Potter, 1997), this difference pre- 
sumably reflects the greater size and age at- 
tained by S. punctata. 
Nursery and spawning grounds 
100 r 
Gonad 
stage 
ii 
□ 
hi 
11 
IV 
m 
V-VIII 
0 L 
i i i i i i i i i i i 
100 200 300 400 500 600 
Total length (mm) 
O- 100 r 
1 23456789 10-13 
Age (years) 
Figure 4 
Percent frequency of occurrence of sequential stages in gonadal 
development in (A) each sequential 50-mm length class, and at 
(B) each age of female Sillaginodes punctata caught between June 
and September. The logistic curve, derived from the percentage of 
mature gonads for each length class, is also shown. Sample sizes 
are given above each length and age class. 
0+ S. punctata were first caught in the shel- 
tered nearshore waters of marine embayments 
of southwestern Australia in late September, 
when their lengths ranged from 14 to 24 mm. 
Because this length range approximates that 
at which this species settles to a benthic habit 
(Jenkins and May, 1994; Bruce, 1995), these 
early juvenile fish would only recently have 
moved into those nearshore waters. The fact 
