266 
Fishery Bulletin 96(2), 1 998 
ported by the fact that juveniles of S. punctata are 
absent in nearshore waters along the southern coast- 
line of southwestern Australia (Lenanton, 1982; 
Ayvazian and Hyndes, 1995), where the shoreline is 
more exposed to rough sea conditions (Hegge et al., 
1996). The relative paucity of sheltered nearshore 
marine habitats on this coastline would account for 
the relatively high densities of juvenile S. punctata 
that are found in the relatively protected waters of 
estuaries in this region (Potter et al., 1993; Potter 
and Hyndes, 1994). 
Estuaries along the southern coast of southwest- 
ern Australia, where the adjacent marine waters 
are exposed to wave and swell activity, may thus pro- 
vide particularly important nursery habitats for 
S. punctata. Many estuaries in this region, however, 
become closed off from the sea during the summer 
and autumn, when, as a result of low freshwater dis- 
charge, a sand bar forms at their mouths (Lenanton 
and Hodgkin, 1985). It is thus relevant that S. punc- 
tata spawns during winter, because this would en- 
able juveniles to enter those estuaries before their 
mouths become closed. This event parallels the situ- 
ation with the mugilids Mugil cephalus and 
xi 
S 
3 
Z 
23 September 
7 October 
20 
* ( 100 ) 
10 
0 
20 
■ ( 100 ) 
10 
0 
20 
' ( 100 ) 
10 
0 
21 October 
20 r 
10 - 
0 - 
20 r 
10 - 
0 - 
( 100 ) 
(52) 
0 
10 
20 
5 December 
_i i i i i 
30 40 50 60 70 
Standard length (mm) 
Figure 7 
Frequency histograms for standard lengths of Sillaginodes 
punctata caught at two weekly intervals by the 5.5-m seine 
net in sheltered nearshore marine waters between Sep- 
tember and December 1994. The numbers in parentheses 
represent the number of fish measured. 
